CA2042722C - Polymeric gas or air filled microballoons usable as suspensions in liquid carriers for ultrasonic echography - Google Patents
Polymeric gas or air filled microballoons usable as suspensions in liquid carriers for ultrasonic echographyInfo
- Publication number
- CA2042722C CA2042722C CA002042722A CA2042722A CA2042722C CA 2042722 C CA2042722 C CA 2042722C CA 002042722 A CA002042722 A CA 002042722A CA 2042722 A CA2042722 A CA 2042722A CA 2042722 C CA2042722 C CA 2042722C
- Authority
- CA
- Canada
- Prior art keywords
- microballoons
- polymer
- membrane
- phase
- hydrophobic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
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Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/22—Echographic preparations; Ultrasound imaging preparations ; Optoacoustic imaging preparations
- A61K49/222—Echographic preparations; Ultrasound imaging preparations ; Optoacoustic imaging preparations characterised by a special physical form, e.g. emulsions, liposomes
- A61K49/223—Microbubbles, hollow microspheres, free gas bubbles, gas microspheres
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
Abstract
Air or gas filled microballoons bounded by an interfacially deposited polymer membrane which can be dispersed in aqueous carrier liquids to be infected into living organisms or administered orally, rectally and urethrally for therapeutic or diagnostic purposes (echography). The properties of the polymeric membrane of the microballoons (elasticity) permeability, biodegradability) can be controlled at will depending on the selected polymer, the interfacial deposition conditions, and the polymer additives.
Description
2~,~27 22 POLYMERIC GAS OR AIR FILLED MICROBALLOONS
USABLE AS SUSPENSIONS IN LIQUID CARRIERS
FOR ULTRASONIC ECHOGRAPHY
The present invention concerns air or gas filled micro-capsules or microballoans enclosed by an organic polymer envelope which can De dispersed or suspended in aqueous media and used in this form for oral, rectal and urethral applications or for in,)ection into living beings, for instance for the purpose of ultrasonic echography and other medical applications.
The invention also comprises a method for making said microballoons in the dry state, the latter being instantly dis-persible in an aqueous liquid carrier to give suspensions with improved properties over existing similar products. Hence, suspensions of the microballoons 1n a carrier liquid ready for administration are also part of the invention.
It is well known that microbodies or microglobules of air ox a gas, e.g. microspheres like microbubbles or microballoons, suspended in a liquid are exceptionally efficient ultrasound reflectors for echography. In this disclosure the term of "microbubble" specifically designates air or gas microspheres in suspension in a carrier liquid which generally result from the introduction therein of air or a gas in divided form, the liquid preferably also containing surfactants or tensides to control the surface properties and the stability of the bubbles. In the microbubbles) the gas to liquid interface essentially comprises loosely bound molecules of the carrier liquid. The term of "microcapsule" or "microballoon" designates preferably air or gas bodies with a material boundary or envelope of molecules other than that of the carrier liquid, i.e. a polymer membrane wall. Both microbubbles and microballoons are useful as ultra-sonic contrast agents. For instance infecting into the blood-stream of living bodies suspensions of gas microbubbles or microballoons (in the range of 0.5 to 10 ~tm) in a carrier liquid will strongly reinforce ultrasonic echography imaging, thus aid-ing in the visualisation of internal organs. Imaging of vessels 20 4~ 27 2 2 and internal organs can strongly help in medical diagnosis, for instance for the detection of cardiovascular and other diseases.
The formation of suspensions of microbubbles in an in,~ectable liquid carrier suitable for echography can be produced by the release of a gas dissolved under pressure in this liquid) or by a chemical reaction generating gaseous products) or by admixing with the liquid soluble or insoluble solids containing air or gas trapped or adsorbed therein.
For instance, in US-A-4,446,442 (Schering), there are dis-closed a series of different techniques for producing suspen-sions of gas microbubbles in a sterilised in,)ectable liquid carrier using (a) a solution of a tenside (surfactant) in a carrier liquid (aqueous) and (b) a solution of a viscosity enhancer as stabilizer. For generating the bubbles, the techni-ques disclosed there include forcing at high velocity a mixture of (a), (b) and air through a small aperture; or in,)ecting (a) into (b) shortly before use together with a physiologically acceptable gas; or adding an acid to (a) and a carbonate to (b), both components being mixed together dust before use and the acid reacting with the carbonate to generate C02 bubbles; or adding an over-pressurized gas to a mixture of (a) and (b) under storage, said gas being released into microbubbles at the time when the mixture is used for infection One problem with microbubbles is that they are generally short-lived even in the presence of stabilizers. Thus) in EP-A-131.540 (Schering)) there is disclosed the preparation of microbubble suspensions in which a stabilized in,~ectable carrier liquid, e.g. a physiological aqueous solution of salt) or a solution of a sugar like maltose) dextrose, lactose or galac-tose, is mixed with solid microparticles (in the 0.1 to 1 ~tm range) of the same sugars containing entrapped air. In order to develop the suspension of bubbles in the liquid carrier, both liquid and solid components are agitated together under sterile conditions for a few seconds and, once made, the suspension must then be used immediately, i.e. it should be in,)ected within 5-10 minutes for echographic measurements; indeed, because the bubbles are evanescent, the concentration thereof becomes too low for being practical after that period.
Another problem with microbubbles for echography after in,~ection is sire. As commonly admitted, microbubbles of useful sire for allowing easy transfer through small blood vessels range from about 0.5 to 10 ~tm; with larger bubbles, there are risks of clots and consecutive emboly. For instance) in the bubble suspensions disclosed in US-A-4,446,442 (Schering) in which aqueous solutions of surfactants such as lecithin) esters and ethers of fatty acids and fatty alcohols with polyoxyethylene and polyoxyethylated polyols like sorbitol, glycols and glycerol, cholesterol, or polyoxy-ethylene-polyoxypropylene polymers, are vigorously shaken with solutions of viscosity raising and stabilising compounds such as mono- and polysaccharides (glucose, lactose, sucrose, dextran, sorbitol);
polyols) e.g. glycerol, polyglycols; and polypeptides like pro-teins, gelatin, oxypolygelatin and plasma protein) only about 50% of the microbubbles are below 40-50 pm which makes such suspensions unsuitable in many echographic application.
In contrast, microcapsules or microballoons have been developed in an attempt to cure some or the foregoing defi-ciencies. As said before, while the microbubbles only have an immaterial or evanescent envelope, i.e. they are only surrounded by a wall of liquid whose surface tension is being modified by the presence of a surfactant) the microballoons or microcapsules have a tangible envelope made of substantive material other than the carrier itself) e.g. a polymeric membrane with definite mechanical strength. In other terms) they are microspheres of solid material in which the air or gas is sore or less tightly encapsulated.
For instance, US-A-4,276,885 (Tickner et al.) discloses using surface membrane microcapsules containing a gas for enhancing ultrasonic images) the membrane including a multi-plicity of non-toxic and non-antigenic organic molecules. In a disclosed embodiment) these microbubbles have a gelatin membrane which resists coalescence and their preferred sire is 5-10 pm.
The membrane of these microbubbles is said to be sufficiently stable for making echographic measurements; however it is also 20 r27 22 said that after a period of time the gas entrapped therein w111 dissolve in the blood-stream and the bubbles will gradually disappear, this being probably due to slow dissolution of the gelatin. Before use, the microcapsules are kept in gelatin solutions in which they are storage stable, but the gelatin needs to be heated and melted to become liquid at the time the suspension is used for making in,~ection.
Microspheres of improved storage stability although without gelatin are disclosed in US-A-4,718,433 (Feinstein). These microspheres are made by sonication (5 to 30 KHz) of viscous protein solutions like 5% serum albumin and have diameters in the 2-20 ~tm range, mainly 2-4 ~tm. The licrospheres are stabilized by denaturation of the membrane forming protein after sonication, for instance by using heat or by chemical means, e.g. by reaction with formaldehyde or glutaraldehyde. The concentration of stable microspheres obtained by this technique is said to be about 8 x 106/m1 in the 2-4 ~tm range) about 106/m1 in the 4-5 ~tm range and less than 5 x 105 in the 5-6 ~tm range.
The stability time of these microspheres is said to be 48 hrs or longer and they permit convenient left heart imaging after intravenous infection. For instance, the sonicated albumin licrobubbles when in,)ected into a peripheral vein are capable of transpullonary passage. This results in echocardiographic opacification of the left ventricle cavity as well as myocardial tissues.
Recently still further improved microballoons for in,)ection ultrasonic echography have been reported in EP-A-324.938 (Widder). In this document there are disclosed high concentra-tions (more than l08) or air-filled protein-bounded sicrospheres of less than 10 ~tm which have life-times of several months or sore. Aqueous suspensions of these sicroballoons are produced by ultrasonic cavitation of solutions of denaturable proteins, e.g.
human serul albusin, which operation also leads to a degree of foaling of the mesbrane-forming protein and its subsequent hardening by heat. Other proteins such as hesoglobin and collagen are said to be convenient also.
Still sore recently M.A. Wheatley et al., Biosaterials 11 2042~~~
(1990), 713-717, have reported the preparation of polymer-coated microspheres by ionotropic gelation of alginate. The reference mentions several techniques to generate the microcapsules; in one case an alginate solution was forced through a needle in an air bet which produced a spray of nascent air filled capsules which were hardened in a bath of 1.2% aqueous CaCl2. In a second case involving co-extrusion of gas and liquid, gas bubbles were introduced into nascent capsules by means of a triple-barelled head, i.e. air was infected into a central capillary tube while an alginate solution was forced through a larger tube arranged coaxially with the capillary tube, and sterile air was flown around it through a mantle surrounding the second tube. Also in a third case, gas was trapped in the alginate solution before spraying either by using a homogeneiser or by sonication. The microballoons thus obtained had diameters in the range 30-100 um, however still oversised for easily passing through lung capillaries.
The high storage stability of the suspensions of micro-balloons disclosed in EP-A-324.938 enables them to be marketed as such, i.e. with the liquid carrier phase, which is a strong commercial asset since preparation before use is no longer necessary. However, the protein material used in this document may cause allergenic reactions with sensitive patients and) moreover) the extreme strength and stability of the membrane material has some drawbacks: for instance, because of their rigidity) the membranes cannot sustain sudden pressure variations to which the microspheres can be subjected, for instance during travel through the blood-stream, these varia-tions of pressure being due to heart pulsations. Thus, under practical ultrasonic tests, a proportion of the microspheres w111 be ruptured which makes imaging reproducibility awkward;
also, these microballoons are not suitable for oral application as they will not resist the digestive ensymes present in the gastrointestinal tract. Moreover, it is known that microspheres with flexible walls are more echogenic than corresponding microspheres with rigid walls.
Furthermore) in the case of infections) excessive stability of the material forming the walls of the microspheres will slow down its biodegradation by the organism under test and may result into metabolization problems. Hence it is much preferable to develop sustaining microballoons bounded by a soft and elastic membrane which can temporarily deform under variations of pressure and endowed with enhanced echogenicity; also it might be visualized that microballoons with controllable biodegradability, for instance made of semi-permeable biodegradable polymers with controlled micro-porosity for allowing slow penetration of biological liquids, would be highly advantageous.
These desirable features have now been achieved with the microballons of the present invention. More specifically, in one aspect, the invention provides microballoons having a mean size in the range of a fraction of a micron to 1,000 microns comprising a biodegradable polymer membrane filled with air or a gas suitable, when in the form of suspensions in a liquid carrier, to be administered to human or animal patients for therapeutic or diagnostic applications, characterised in that the membrane polymer is a synthetic, deformable, resilient and interfacially depositable polymer, the membrane having a thickness between 50 and 500 nm.
In a further aspect, the invention provides air or gas A
filled microballoons comprising an elastic interfacial synthetic polymeric membrane, adapted to form, with a physiologically acceptable aqueous liquid carrier, stable aqueous suspensions capable of being taken orally, rectally and urethrally, or injectable into living organisms for therapeutic or diagnostic purposes, the microballoons being non-coalescent, dry and instantly dispersible in said liquid carrier, the polymeric membrane having a thickness between 50 and 500 nm.
Moreover, although the present microspheres can generally be made relatively short-lived, i.e. susceptible to biodegradation to cope with the foregoing metabolization problems by using selected types of polymers, this feature (which is actually controlled by the fabrication parameters) is not a commercial drawback because either the microballoons can be stored and shipped dry, a condition in which they are stable indefinitely, or the membrane can be made substantially impervious to the carrier liquid, degradation starting to occur only after injection. In the first case, the microballoons supplied in dry powder form are simply admixed with a proportion of an aqueous phase carrier before use, this proportion being selected depending on the needs. Note that this is an additional advantage over the prior art products because the concentration can be - 6a -.F
20 ~2~ Za chosen at will and initial values far exceeding the aforementioned 108/m1, i.e. in the range 105 to 101°, are readily accessible. It should be noted that the method of the invention (to be disclosed hereafter) enables to control porosity to a wide extent; hence microballoons with a substantially impervious membrane can be made easily which are stable in the form of suspensions in aqueous liquids and which can be marketed as such also.
Microspheres with membranes of interfacially deposited polymers as defined above, although in the state where they are filled with liquid, are well known in the art. They may - 6b -' 2042722 normally result from the emulsification into droplets (the size of which is controllable in function to the emulsification parameters) of a first aqueous phase in an organic solution of polymer followed by dispersion of this amulsion into a second water phase and subsequent evaporation of the organic solvent.
During evaporation of the volatile solvent, the polymer deposits interfacially at the droplets boundary and forms a microporous membrane which efficiently bounds the encapsulated first aqueous phase from the surrounding second aqueous phase. This technique, although possible, is not preferred in the present invention.
Alternatively, one may emulsify with an emulsifier a hydro-phobic phase in an aqueous phase (usually containing viscosity increasing agents as emulsion stabilizers) thus obtaining an oil-in-water type emulsion of droplets of the hydrophobic phase and thereafter adding thereto a membrane forming polymer dissolved in a volatile organic solvent not miscible with the aqueous phase.
If the polymer is insoluble in the hydrophobic phase) it will deposit interfacially at the boundary between the droplets and the aqueous phase. Otherwise, evaporation of the volatile solvent will lead to the formation of said interfacially depo-sited membrane around the droplets of the emulsified hydrophobic phase. Subsequent evaporation of the encapsulated volatile hydrophobic phase provides water filled microspheres surrounded by interfacially deposited polymer membranes. This technique which is advantageously used in the present invention is disclosed by R. Uno et al, in J. Microencapsulation 1 (1984)) 3-8 and R. Makino et al., Chem. Pharm. Bull. 33 (1984), 1195-l201.
As said before, the size of the droplets can be controlled by changing the emulsification parameters) i.e. nature of emul-sifier (more effective the surfactant, i.e. the larger the hydrophilic to lipophilic balance, the smaller the droplets) and the stirring conditions (faster and more energetic the agita-tion) the smaller the droplets).
In another variant) the interfacial wall forming polymer is dissolved in the starting hydrophobic phase itself; the latter is emulsified into droplets in the aqueous phase and the 20 ~ 27 2 2 membrane around the droplets w111 form upon subsequent evapora-tion of this encapsulated hydrophobic phase. An example of this is reported by J.R. Farnand et al,) Powder Technology 22 (1978), 11-16 who emulsify a solution of polymer (e.g. polyethylene) in naphthalene in boiling water, then after cooling they recover the naphthalene in the form of a suspension of polymer bounded microbeads in cold water and, finally, they remove the naphthalene by subjecting the microbeads to sublimation, whereby 25 ~tm microballoons are produced. Other examples exist, in which a polymer is dissolved in a mixed hydrophobic phase comprising a volatile hydrophobic organic solvent and a water-soluble organic solvent, then this polymer solution is emulsified in a water phase containing an emulsifier, whereby the water-soluble sol-vent disperses into the water phase, thus aiding in the formation of the emulsion of microdroplets of the hydrophobic phase and causing the polymer to precipitate at the interface;
this is disclosed in EP-A-274.961 (H. Fessi).
The aforementioned techniques can be adapted to the pre-paration of air or gas filled microballoons suited for ultra-sonic imaging provided that appropriate conditions are found to control sphere sire in the desired ranges, cell-wall permeabi-lity or imperviousness and replacement of the encapsulated liquid phase by air or a selected gas. Control of overall sphere sire is obviously important to adapt the microballoons to use purposes, i.e. in,~ection or oral intake. The siee conditions for in,~ection (about 0.5 - 10 pm average sire) have been discussed previously. For oral application) the range can be much wider, being considered that echogenicity increases with sire; hence microballoons in several sire ranges between say 1 and 1000 ~tm can De used depending on the needs and provided the membrane is elastic enough not to break during transit in the stomach and intestine. Control of cell-wall permeability is important to ensure that Infiltration by the in~ectable aqueous carrier phase is absent or slow enough not to impair the echographic measurements but) in cases, still substantial to ensure relatively fast after-test biodegradability, l.e. ready metaboli-2ation of the suspension by the organism. Also the microporous .__ structure of the microballoons envelope (pores of a few nm to a few hundreds of nm or more for microballoons envelopes of thickness ranging from 50-500 nm) is a factor of resiliency, i.e. the microspheres can readily accept pressure variations without breaking. The preferred range of pore sizes is about 50-2000 nm.
The conditions for achieving these results are met by using a method for making air or gas filled microballoons usable as suspensions in a carrier liquid for oral, rectal and urethral applications, or for injections into living organisms, said method comprising the steps of:
(1) emulsifying a hydrophobic organic phase into a water phase so as to obtain droplets of said hydrophobic phase as an oil-in-water emulsion in said water phase:
(2) adding to said emulsion a solution of at least one polymer in a volatile solvent insoluble in the water phase, so that a layer of said polymer will form around said droplets (3) evaporating said volatile solvent so that the polymer will deposit by interfacial precipitation around the droplets which then form beads with a core of said hydrophobic phase encapsulated by a membrane of said polymer, said beads being in suspension in said water phase and (4) subjecting said suspension to reduced pressure under conditions such that said encapsulated hydrophobic phase is removed by evaporation; wherein said hydrophobic phase is selected so that it evaporates substantially simultaneously with the water phase and is replaced by air or gas, whereby dry, free flowing, readily dispersible microballoons are obtained.
One factor which enables to control the permeability of the microballoons membrane is the rate of evaporation of the hydrophobic phase relative to that of water in step (4) of the method, e.g., under conditions of freeze drying. For instance if the evaporation in is carried out between about -40 and 0°C, and hexane is used as the hydrophobic phase, polystyrene being the interfacially deposited polymer, beads with relatively large pores are obtained: this is so because the vapour pressure of the hydrocarbon in the chosen temperature range is significantly greater than that of water, which means that the pressure difference between the inside and outside of the spheres will tend to increase the size of the pores in the spheres membrane through which the inside material will be evaporated. In contrast, using cyclooctane as the hydrophobic phase (at -17°C the vapour pressure is the same as that of water) will provide beads with very tiny pores because the difference of pressures - 9a -between the inside and outside of the spheres during evaporation is minimized.
Depending on degree of porosity the microballoons of this invention can be made stable in an aqueous carrier from several hours to several months and give reproducible echographic signals for a long period of time. Actually, depending on the polymer selected, the membrane of the microballoons can be made substantially impervious when suspended in carrier liquids of appropriate osmotic properties, i.e. containing solutes in appropriate concentrations. It should be noted that the existence of micropores in the envelope of the microballoons of the present invention appears to be also related with the - 9b -~. :_:
l~ 20 Q27 22 echographic response, i.e.) a11 other factors being constant, microporous vesicles provide more efficient echographic signal than corresponding non-porous vesicles. The reason is not known but it can be postulated that when a gas is in resonance in a closed structure, the damping properties of the latter may be different if it is porous or non-porous.
Other non water soluble organic solvents which have a vapour pressure of the same order of magnitude between about -!0°C and 0°C are convenient as hydrophobic solvents in this invention. These include hydrocarbons such as for instance n-octane, cyclooctane) the dimethyicyclohexanes, ethyl-cyclo-hexane, 2-, 3- and 4-aethyl-heptane) 3-ethyl-hexane, toluene, xylene) 2-methyl-2-heptane, 2,2,3,3-tetramethylbutane and the like. Esters such as propyl and isopropyl butyrate and isobuty-rate) butyl-formats and the like, are also convenient in this range. Another advantage of freese drying is to operate under reduced pressure of a gas instead of air) whereby gas filled microballoons will result. Physiologically acceptable gases such as C02, H20, methane, Freon~;~'helium and other rare gases are possible. Gases with radioactive tracer activity can be contemplated.
As the volatile solvent insoluble in water to be used for dissolving the polymer to be precipitated interfacially, one can cite halo-compounds such as CC1,1, CH38r) CH2C12) chloroform, Freon, low boiling esters such as aethyl) ethyl and propyi acetate as well as lower ethers and ketones of low water solubi-lity. When solvents not totally insoluble in water are used, e.g. diethyl-ether) it is advantageous to use, as the aqueous phase, a water solution saturated with acid solvent beforehand.
The aqueous phase in which the hydrophobic phase is emul-sified as an oil-in-water emulsion preferably contains 1-20x by weight of water-soluble hydrophilic coapounds lilts sugars and polymers as stabilisers, e.g. polyvinyl alcohol (PVA)) polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), gelatin) polyglu-tamic acid, albuain) and polysaccharides such as starch, dextran, agar, xanthan and the like. Siailar aqueous phases can be used as the carrier liquid in which the microballoons are .
suspended before use.
Part of this Water-soluble polymer can remain in the envelope of the microballoons or it can be removed by washing the beads before subjecting them to final evaporation of the encapsulated hydrophobic core phase.
The emulsifiers to be used (0.1-5% by weight) to provide the oil-in-water emulsion of the hydrophobic phase in the aqueous phase include most physiologically acceptable emulsi-fiers, for instance egg lecithin or soya bean lecithin, or synthetic lecithins such as saturated synthetic lecithins) for example) dimyristoyl phosphatidyl choline) dipalmitoyl phospha-tidyl choline or distearoyl phosphatidyl choline or unsaturated synthetic lecithins, such as dioleyl phosphatidyl choline or dilinoleyl phosphatidyl choline. Emulsifiers also include sur-factants such as free fatty acids) esters of fatty acids with polyoxyalkylene compounds like polyoxypropylene glycol and polyoxyethylene glycol; ethers of fatty alcohols with polyoxy-alkylene glycols; esters of fatty acids with polyoxyalkylated sorbitan; soaps; glycerol-polyalkylene stearate; glycerol-poly-oxyethylene ricinoleate; homo- and copolymers of polyalkylene glycols; polyethoxylated soya-oil and castor oil as well as hydrogenated derivatives; ethers and esters of sucrose or other carbohydrates with fatty acids, fatty alcohols, these being op-tionally polyoxyalkylated; mono-, di- and triglycerides of satu-rated or unsaturated fatty acids; glycerides or soya-o11 and sucrose.
The polymer which constitutes the envelope or bounding membrane of the in~ectable microballoons can be selected from most hydrophilic, biodegradable physiologically compatible poly-mers. Among such polymers one can cite polysaccharides of low water solubility) polylactides and polyglycolides and their copolysers) copolymers of lactides and lactones such as e-caprolactone, a-valerolactone, polypeptides) and proteins such as gelatin) collagen) globulins and albumins. The great versatility in the selection of synthetic polymers is another advantage of the present invention since, as with allergic patients, one may wish to avoid using microballoons made of natural proteins (albumin, gelatin) like in US-A-4,276,885 or EP-A-324.938. Other suitable polymers include poly-(ortho)esters (see for instance US-A-4,093,709; US-A-4,13l,648; US-A-4,138,344; US-A-4,180,646); polylactic and poiyglycoiic acid and their copoly~era, for instance DEXON (see J. Heller) Biomateriala ~ (l980), 51; poly(DL-lactide-co-d-caprolactone), poly(DL-lactide-co-d-valerolactone), poly(DL-lactide-co-~ -butyrolactone)) polyalkylcyanoacrylates; polyamides, polyhydroxy-butyrate; polydioxanone; poly-S-aminoketonea (Polymer ~ (1982), 1693); polyphoaphasenes (Science ~ (l976)) 1214); and polyanhydridea. References on biodegradable polymers can be found in R. Longer et al., Nacromol. Chem. Phys. ~ (1983), 61-126. Polyamino-acids such as polyglutamic and polyaspartic acids can also be used as well as their derivatives, i.e. partial eaters with lower alcohols or glycols. One useful example of such polymers la poly-(t. butyl-glutamate). Copolymers with other amino-acids such as methionine, leucine, valine) proline, glycine, alamine) etc. are also possible. Recently some novel derivatives of polygiutamic and polyaspartic acid with controlled biodegradability have been reported (see W087/03891;
US 4,888,398 and EP-l30.935. These polyeera (and copolymers with other amino-acids) have forwulne of the following types -(NH-CHA-CO)x(NH-CHX-CO)y where X designates the aide chain of an amino-acid residue and A
is a group of formula -(CH2)nC00RiR2-OCOR (II), with R1 and R2 being H or lower altyls) and R being alkyl or aryl; or R and R1 ere connected together by a substituted or unsubstituted linking member to provide 5- or 6- mesbered rings.
A can also represent groups of formulae:
-(CH2)nC00-CHRiC00R (I) and h ..
-(CH2)nC0(NH-CHX-CO)mNH-CH(COOH)-(CH2)pC00H (III) and corresponding anhydrides. In a11 these formulae n) m and p are lower integers (not exceeding 5) and x and y are also integers selected for having molecular weights not below 5000.
The aforementioned polymers are suitable for caking the microballoons according to the invention and) depending on the nature of substituents R, Rl, R2 and X, the properties of the membrane can be controlled, for instance, strength, elasticity and biodegradability. For instance X can be methyl (alanine), isopropyl (valine), isobutyl (leucine and isoleucine), benzyl (phenylalanine).
Additives can be incorporated into the polymer wall of the microballoons to modify the physical properties such as disper-sibility, elasticity and water permeability. For incorporation in the polymer, the additives can be dissolved in the polymer carrying phase, e.g. the hydrophobic phase to be emulsified in the water phase, whereby they will co-precipitate with the polymer during inter-facial membrane formation.
Among the useful additives, one may cite compounds which can "hydrophobise" the microballoons membrane in order to decrease water permeability, such as fats) waxes and high molecular-weight hydrocarbons. Additives which improve dispersi-bility of the microballoons in the in~ectable liquid-carrier are amphipatic compounds like the phospholipids; they also increase water permeability and rate of biodegradability.
Hon-biodegradable polymers for making microballoons to be used in the digestive tract can be selected from most water-insoluble) physiologically acceptable) bioresistant polymers including polyolefins (polystyrene), acrylic resins (polyacry-lates, polyacrylonitrile), polyesters (polycarbonate), polyure-thanes, polyurea and their copolyuers. ABS (acryl-butadiene-styrene) is a preferred copolymer.
Additives which increase membrane elasticity are the plas-ticizers like isopropyl myristate and the like. Also, very useful additives are constituted by polymers akin to that of the mee~brane itself but with relatively low molecular weight. For __ 2 0 4~ 2 7 2 ~
1 ~!
instance when using copolymers of polylactic/polyglycolic type as the membrane forming materiel, the properties of the membrane can be modified advantageously (enhenced softness and biodegra-dability) by incorporating, as additives) loW molecular weight (1000 to 15,000 Dalton) polyglycolidea or ~polylactides. Also polyethylene glycol of moderate to low Mw (e.g. PEG 2000) is a useful softening additive.
The quantity of additives to be incorporated in the polymer forming the inter-tacially deposited membrane of the present microballoona is extremely variable and depends on the needs. In some cases no additive is used at all; in other cases amounts of additives which may reach about 20% by weight of the polymer are possible'.
The in~ectable microballoons of the present invention can be stored dry in the presence or in the absence of additives to improve conservation and prevent coalescence. As additives, one may select from O.l to 25% by weight of water-soluble physiolo-gically acceptable compounds such as mannitol) galactose) lactose or sucrose or hydrophilic polymers like dextran) xanthan, agar, starch, PVP) poiyglutamic acid) polyvinylalcohol (PVA)) albumin and gelatin. The useful life-time of the microbailoons in the in~ectable liquid carrier phase, i.e. the period during which useful echographic signals are observed, can be controlled to last from a few minutes to several months depending on the needs; this can be done by controlling the porosity of the membrane from substantial imperviousness toward carrier liquids to poroaities having pores of a few nanometers to several hundreds of nanometers. This degree of porosity can be controlled) in addition to properly selecting the membrane forming polymer and polymer additives, by adjusting the evaporation rate and temperature in step (~) of the method and properly selecting the nature o! the compound (or mixture of compounds) constituting the hydrophobic phase, i.e.
the greater the differences in its partial pressure of evapora-tion with that of the water phase, the coarser the pores in the microballoons membrane will be. Of course, this control by se-lection of the hydrophobic phase can be further refined by the 204~'~22 choice of stabilizers and by ad,~usting the concentration thereof in order to control the rate of water evaporation during the forming of the microballoons. A11 these changes can easily be made by skilled ones without exercizing inventiveness and need not be further discussed.
It should be remarked that although the microballoons of this invention can be marketed in the dry state, more parti-cularly when they are designed with a limited life time after in,~ection, it may be desirable to also sell ready preparations, i.e. suspensions of microballoons in an aqueous liquid carrier ready for in,~ection or oral administration. This requires that the membrane of the microballoons be substantially impervious (at least for several months or more) to the carrier liquid. It has been shown in this description that such conditions can be easily achieved with the present method by properly selecting the nature of the polymer and the interfacial deposition parameters. Actually parameters have been found (for instance using the polyglutamic polymer (where A is the group of formula II) and cyclooctane as the hydrophobic phase) such that the porosity of the membrane after evaporation of the hydrophobic phase is so tenuous that the microballoons are substantially impervious to the aqueous carrier liquid in which they are suspended.
A preferred administrable preparation for diagnostic purposes comprises a suspension in buffered or unbuffered saline (0.9% aqueous NaCl; buffer 10 wM tris-HC1) containing 108-1010 vesicles/ml. This can be prepared mainly according to the directions of the Examples below, preferably Examples 3 and 4, using poly-(DL-lactide) polymers from the Company Boehringer, Ingelheim) Germany.
The following Examples illustrate the invention practically.
Example 1 One gram of polystyrene was dissolved in 19 g of liquid naphthalene at 100°C. This naphthalene solution was emulsified at 90-95°C into 200 ml of a water solution of polyvinyl alcohol ib 20 427 22 (PVA) (4% by weight) containing 0.1X of Tween-40 eaulsifier. The eaulsifying head vas a Polytron PT-3000 at about 10,000 rpa.
Then the eaulaion vas diluted under agitation with 500 al of the aaae aqueous phase at 15°C whereby the naphthalene droplets solidified into Deads of lean than 50 Vita as ascertained by passing through a 50 Vita aeah screen. The suspension was centrifugated under l000 g and the beads were washed with water and recentrifugated. This step vas repeated twice.
The beads were reauapended in 100 al of water with 0.8 g of dissolved lactose and the suspension was frown into a block at -30°C. The block was thereafter evaporated under about 0.5-2 Torr between about -20 and -10°C. Air filled aicroballoons of average sire 5-10 ua and controlled porosity were thus obtained which gave an echographic signal at 2.25 and 7.5 MHs after being dispersed in water (3% dispersion by weight). The stability of the aicroballoons in the dry state was effective for an indefinite period of tine; once suspended in an aqueous carrier liquid the useful life-tine for echography was about 30 sin or sore. Polystyrene being non-biodegradable, this aateriai was not favored for infection echography but was useful for digestive tract investigations. This Exaaple clearly establishes the feasibility of the aethod of the invention.
Exaanle 2 A 50i50 copolyAer aixture (0.3 g) of DL-lactide and glycolide (Du Pont Me.d.iaorb) and 16 ag of egg-lecithin were dissolved in 7.5 al of CHC13 to give solution (1).
A solution (2) containing 20 ag of paraffin-wax (M.P. 54-56°C) in 10 al of cyclooctane (M.P. 10-13 °) was prepared and eaulaified in 150 al of a water solution (0.13% by weight) of Pluronic F-108 (a block copolyaer of ethylene oxide and propy-lene oxide) containing also 1.2 g of CHC13. Eaulsification vas carried out at rooa teaperature for 1 sin with a Polytron head at 7000 rpa. Then solution (1) was added under agitation (7000 rpa) and) after about 30-60 $ec, the eaulsifier head vas replaced by a helical agitator (500 rpa) and stirring vas conti-nued for about 3 hrs at rooa teaperature (22°C). The suspension 1~ 20 ~z~ 22 was passed through a 50 ~tm screen and frosen to a block which was subsequently evaporated between -20 and 0°C under high-vacuum (catching trap -60 to -80°C). There were thus obtained 0.264 g (88%) of air-filled microballoons stable in the dry state.
Suspensions of said microballoons in water (no stabilisers) gave a strong echographic signal for at least one hour. After infection in the organism, they biodegraded in a few days.
Example 3 A solution was made using 200 ml of tetrahydrofuran (THF), 0.8 g of a 50i50 DL-lactide/glycolide copolymer (Boehringer AG), 80 mg of egg-lecithin, 64 mg of paraffin-wax and 4 ml of octane.
This solution was emulsified by adding slowly into 400 ml of a 0.1% aqueous solution of Pluronic F-l08 under helical agitation (500 r.p.m.). After stirring for 15 min, the milky TM
dispersion was evaporated under 10-12 Torr 25°C in a rotavapor until its volume was reduced to about 400 ml. The dispersion was sieved on a 50 ~tm grating) then it was frosen to -40°C and freese-dried under about 1 Torr. The residue, 1.32 g of very fine powder, was taken with 40 ml of distilled water which provided, after 3 min of manual agitation, a very homogeneous dispersion of microballoons of average alas 4.5 ~Cm as measured TM
using a particle analyser (Nastersiser from Malvern). The concentration of microballoons (Couiter Counter) was about 2 x 109/m1. This suspension gave strong echographic signals which persisted for about 1 hr.
If in the present example, the additives to the membrane polymer are omitted) i.e. there is used only 800 mg of the lactide/glycoiide copolyAer in the THF/octane solution) a dramatic decrease in cell-wall permeability is observed, the echographic signal of the dispersion in the aqueous carrier not being significantly attenuated after 3 days.
Using intermediate quantities of additives provided beads with controlled intermediate porosity and life-time.
EXBmDle 4 There was used in this Example a polymer of formula defined in claim 8 in which the side group has formula (II) where R1 and R2 are hydrogen and R is tert.butyi. The preparation of this polymer (defined as poly-POMEG) is described in !JS-A-4,888,398.
The procedure was like in Example 3, using 0.1 g poly-POMEG, 70 ml of THF, 1 ml of cyclooctane and 100 ml of a 0.1%
aqueous solution of Pluronic'~' F-108. No lecithin or high-molecular weight hydrocarbon was added. The milky emulsion was evaporated at 27C/10 Torr until the residue was about 100 ml, then it was screened on a 50 ~tm mesh and frosen. Evaporation of the frown block was carried out (0.5-1 Torr) until dry. The yield was 0.18 g because of the presence of the surfactant. This was dispersed in l0 ml of distilled water and counted with a Coulter Counter. The measured concentration was found to be 1,43 x l09 microcapsules/ml, average sire 5.21 ~tm as determined with a particle analyser (Mastersiser from Malvern). The dispersion was diluted 100 x, i.e. to give about 1.5 x 107 microspheres/ml and measured for echogenicity. The ampiitude of the echo signal was 5 times greater at 7.5 MHs than at 2.25 MHs.
These signals were reproducible for a long period of time.
Echogenicity measurements were performed with a pulse-echo system consisting of a plexigiaa specimen holder (diameter 30 mm) with a 20 ~tm thick Mylar acoustic window, a transducer holder immersed in a constant temperature water bath) a puiser-receiver (Accutron M3010JS) with an external pre-amplifier with a fixed gain of 40 dB and an internal amplifier with gain ad~ustabie from -40 to +40 dB and interchangeable 13 mm unfocused transducers. A 10 MHs low-pass filter was inserted in the receiving part to improve the signal to noise ratio. The A/D
board in the IBM PC was a Sonotek STR 832. Measurements were carried out at 2.25, 3.5, 5 and 7.5 MHs.
If in the present Example, the polymer used is replaced by lactic-lactone copolymers, the lactones being ~ -butyrolactone, a-valerolactone or e-caprolactone (see Fukusaki et al., J.
Biomedical Mater. Res. 25 (l991), 315-328), similar favorable results were obtained. Also in a similar context, polyalkylcyano-i9 2042722 acrylatea and particularly a 90:10 copolymer poly(DL-lactide-co-glycolide) gave satisfactory results. Finally, a preferred poly-mer is a poly(DL-lactide) from the Company Boehringer-Ingelheim sold under the trademark "Resomer R-206" or Resomer R-207.
Example Two-dimensional echocardiography was performed using an Acuson-128 apparatus with the preparation of Example 4 (l.43 x 109/m1) in an experimental dog following peripheral vein infection of 0.1-2 ml of the dispersion. After normally expected contrast enhancement imaging of the right heart, intense and persistent signal enhancement of the left heart with clear outlining of the endocardium was observed) thereby confirming that the microballoons made with poly-POMEG (or at least a significant part of them) were able to cross the pulmonary capillary circulation and to remain in the blood-stream for a time sufficient to perform efficient echographic analysis.
In another series of experiments, persistent enhancement of the Doppler signal from systemic arteries and the portal vein vas observed in the rabbit and in the rat following peripheral vein infection of 0.5-2 ml of a preparation of microballoons prepared as disclosed in Example 4 but using poly(DL-lactic acid) as the polymer phase. The composition used contained 1.9 x 108 veaiclea/ml.
Another composition prepared also according to the direc-tions of Example 4 was achieved using poly(tert.butyl-glutamate). This composition (0.5 ml) at dilution of 3.4 x l08 microballoona/mi was infected in the portal vein of rata and gave persistent contrast enhancement of the liver parenchyma.
Examvle 6 A microballoon suspension (l.l x 109 vesicles/mi) was prepared as disclosed in Example 1 (resin = polystyrene). One ml of this suspension vas diluted with 100 ml of 300 mM mannitol solution and 7 ml of the resulting dilution vas administered intragaatricaliy to a laboratory rat. The animal was examined with an Acuaon-l28 apparatus for 2-dimensional echography 20 ~2~ Za imaging of the digestive tract Which clearly shoaled the single loops of the small intestine and of the colon.
USABLE AS SUSPENSIONS IN LIQUID CARRIERS
FOR ULTRASONIC ECHOGRAPHY
The present invention concerns air or gas filled micro-capsules or microballoans enclosed by an organic polymer envelope which can De dispersed or suspended in aqueous media and used in this form for oral, rectal and urethral applications or for in,)ection into living beings, for instance for the purpose of ultrasonic echography and other medical applications.
The invention also comprises a method for making said microballoons in the dry state, the latter being instantly dis-persible in an aqueous liquid carrier to give suspensions with improved properties over existing similar products. Hence, suspensions of the microballoons 1n a carrier liquid ready for administration are also part of the invention.
It is well known that microbodies or microglobules of air ox a gas, e.g. microspheres like microbubbles or microballoons, suspended in a liquid are exceptionally efficient ultrasound reflectors for echography. In this disclosure the term of "microbubble" specifically designates air or gas microspheres in suspension in a carrier liquid which generally result from the introduction therein of air or a gas in divided form, the liquid preferably also containing surfactants or tensides to control the surface properties and the stability of the bubbles. In the microbubbles) the gas to liquid interface essentially comprises loosely bound molecules of the carrier liquid. The term of "microcapsule" or "microballoon" designates preferably air or gas bodies with a material boundary or envelope of molecules other than that of the carrier liquid, i.e. a polymer membrane wall. Both microbubbles and microballoons are useful as ultra-sonic contrast agents. For instance infecting into the blood-stream of living bodies suspensions of gas microbubbles or microballoons (in the range of 0.5 to 10 ~tm) in a carrier liquid will strongly reinforce ultrasonic echography imaging, thus aid-ing in the visualisation of internal organs. Imaging of vessels 20 4~ 27 2 2 and internal organs can strongly help in medical diagnosis, for instance for the detection of cardiovascular and other diseases.
The formation of suspensions of microbubbles in an in,~ectable liquid carrier suitable for echography can be produced by the release of a gas dissolved under pressure in this liquid) or by a chemical reaction generating gaseous products) or by admixing with the liquid soluble or insoluble solids containing air or gas trapped or adsorbed therein.
For instance, in US-A-4,446,442 (Schering), there are dis-closed a series of different techniques for producing suspen-sions of gas microbubbles in a sterilised in,)ectable liquid carrier using (a) a solution of a tenside (surfactant) in a carrier liquid (aqueous) and (b) a solution of a viscosity enhancer as stabilizer. For generating the bubbles, the techni-ques disclosed there include forcing at high velocity a mixture of (a), (b) and air through a small aperture; or in,)ecting (a) into (b) shortly before use together with a physiologically acceptable gas; or adding an acid to (a) and a carbonate to (b), both components being mixed together dust before use and the acid reacting with the carbonate to generate C02 bubbles; or adding an over-pressurized gas to a mixture of (a) and (b) under storage, said gas being released into microbubbles at the time when the mixture is used for infection One problem with microbubbles is that they are generally short-lived even in the presence of stabilizers. Thus) in EP-A-131.540 (Schering)) there is disclosed the preparation of microbubble suspensions in which a stabilized in,~ectable carrier liquid, e.g. a physiological aqueous solution of salt) or a solution of a sugar like maltose) dextrose, lactose or galac-tose, is mixed with solid microparticles (in the 0.1 to 1 ~tm range) of the same sugars containing entrapped air. In order to develop the suspension of bubbles in the liquid carrier, both liquid and solid components are agitated together under sterile conditions for a few seconds and, once made, the suspension must then be used immediately, i.e. it should be in,)ected within 5-10 minutes for echographic measurements; indeed, because the bubbles are evanescent, the concentration thereof becomes too low for being practical after that period.
Another problem with microbubbles for echography after in,~ection is sire. As commonly admitted, microbubbles of useful sire for allowing easy transfer through small blood vessels range from about 0.5 to 10 ~tm; with larger bubbles, there are risks of clots and consecutive emboly. For instance) in the bubble suspensions disclosed in US-A-4,446,442 (Schering) in which aqueous solutions of surfactants such as lecithin) esters and ethers of fatty acids and fatty alcohols with polyoxyethylene and polyoxyethylated polyols like sorbitol, glycols and glycerol, cholesterol, or polyoxy-ethylene-polyoxypropylene polymers, are vigorously shaken with solutions of viscosity raising and stabilising compounds such as mono- and polysaccharides (glucose, lactose, sucrose, dextran, sorbitol);
polyols) e.g. glycerol, polyglycols; and polypeptides like pro-teins, gelatin, oxypolygelatin and plasma protein) only about 50% of the microbubbles are below 40-50 pm which makes such suspensions unsuitable in many echographic application.
In contrast, microcapsules or microballoons have been developed in an attempt to cure some or the foregoing defi-ciencies. As said before, while the microbubbles only have an immaterial or evanescent envelope, i.e. they are only surrounded by a wall of liquid whose surface tension is being modified by the presence of a surfactant) the microballoons or microcapsules have a tangible envelope made of substantive material other than the carrier itself) e.g. a polymeric membrane with definite mechanical strength. In other terms) they are microspheres of solid material in which the air or gas is sore or less tightly encapsulated.
For instance, US-A-4,276,885 (Tickner et al.) discloses using surface membrane microcapsules containing a gas for enhancing ultrasonic images) the membrane including a multi-plicity of non-toxic and non-antigenic organic molecules. In a disclosed embodiment) these microbubbles have a gelatin membrane which resists coalescence and their preferred sire is 5-10 pm.
The membrane of these microbubbles is said to be sufficiently stable for making echographic measurements; however it is also 20 r27 22 said that after a period of time the gas entrapped therein w111 dissolve in the blood-stream and the bubbles will gradually disappear, this being probably due to slow dissolution of the gelatin. Before use, the microcapsules are kept in gelatin solutions in which they are storage stable, but the gelatin needs to be heated and melted to become liquid at the time the suspension is used for making in,~ection.
Microspheres of improved storage stability although without gelatin are disclosed in US-A-4,718,433 (Feinstein). These microspheres are made by sonication (5 to 30 KHz) of viscous protein solutions like 5% serum albumin and have diameters in the 2-20 ~tm range, mainly 2-4 ~tm. The licrospheres are stabilized by denaturation of the membrane forming protein after sonication, for instance by using heat or by chemical means, e.g. by reaction with formaldehyde or glutaraldehyde. The concentration of stable microspheres obtained by this technique is said to be about 8 x 106/m1 in the 2-4 ~tm range) about 106/m1 in the 4-5 ~tm range and less than 5 x 105 in the 5-6 ~tm range.
The stability time of these microspheres is said to be 48 hrs or longer and they permit convenient left heart imaging after intravenous infection. For instance, the sonicated albumin licrobubbles when in,)ected into a peripheral vein are capable of transpullonary passage. This results in echocardiographic opacification of the left ventricle cavity as well as myocardial tissues.
Recently still further improved microballoons for in,)ection ultrasonic echography have been reported in EP-A-324.938 (Widder). In this document there are disclosed high concentra-tions (more than l08) or air-filled protein-bounded sicrospheres of less than 10 ~tm which have life-times of several months or sore. Aqueous suspensions of these sicroballoons are produced by ultrasonic cavitation of solutions of denaturable proteins, e.g.
human serul albusin, which operation also leads to a degree of foaling of the mesbrane-forming protein and its subsequent hardening by heat. Other proteins such as hesoglobin and collagen are said to be convenient also.
Still sore recently M.A. Wheatley et al., Biosaterials 11 2042~~~
(1990), 713-717, have reported the preparation of polymer-coated microspheres by ionotropic gelation of alginate. The reference mentions several techniques to generate the microcapsules; in one case an alginate solution was forced through a needle in an air bet which produced a spray of nascent air filled capsules which were hardened in a bath of 1.2% aqueous CaCl2. In a second case involving co-extrusion of gas and liquid, gas bubbles were introduced into nascent capsules by means of a triple-barelled head, i.e. air was infected into a central capillary tube while an alginate solution was forced through a larger tube arranged coaxially with the capillary tube, and sterile air was flown around it through a mantle surrounding the second tube. Also in a third case, gas was trapped in the alginate solution before spraying either by using a homogeneiser or by sonication. The microballoons thus obtained had diameters in the range 30-100 um, however still oversised for easily passing through lung capillaries.
The high storage stability of the suspensions of micro-balloons disclosed in EP-A-324.938 enables them to be marketed as such, i.e. with the liquid carrier phase, which is a strong commercial asset since preparation before use is no longer necessary. However, the protein material used in this document may cause allergenic reactions with sensitive patients and) moreover) the extreme strength and stability of the membrane material has some drawbacks: for instance, because of their rigidity) the membranes cannot sustain sudden pressure variations to which the microspheres can be subjected, for instance during travel through the blood-stream, these varia-tions of pressure being due to heart pulsations. Thus, under practical ultrasonic tests, a proportion of the microspheres w111 be ruptured which makes imaging reproducibility awkward;
also, these microballoons are not suitable for oral application as they will not resist the digestive ensymes present in the gastrointestinal tract. Moreover, it is known that microspheres with flexible walls are more echogenic than corresponding microspheres with rigid walls.
Furthermore) in the case of infections) excessive stability of the material forming the walls of the microspheres will slow down its biodegradation by the organism under test and may result into metabolization problems. Hence it is much preferable to develop sustaining microballoons bounded by a soft and elastic membrane which can temporarily deform under variations of pressure and endowed with enhanced echogenicity; also it might be visualized that microballoons with controllable biodegradability, for instance made of semi-permeable biodegradable polymers with controlled micro-porosity for allowing slow penetration of biological liquids, would be highly advantageous.
These desirable features have now been achieved with the microballons of the present invention. More specifically, in one aspect, the invention provides microballoons having a mean size in the range of a fraction of a micron to 1,000 microns comprising a biodegradable polymer membrane filled with air or a gas suitable, when in the form of suspensions in a liquid carrier, to be administered to human or animal patients for therapeutic or diagnostic applications, characterised in that the membrane polymer is a synthetic, deformable, resilient and interfacially depositable polymer, the membrane having a thickness between 50 and 500 nm.
In a further aspect, the invention provides air or gas A
filled microballoons comprising an elastic interfacial synthetic polymeric membrane, adapted to form, with a physiologically acceptable aqueous liquid carrier, stable aqueous suspensions capable of being taken orally, rectally and urethrally, or injectable into living organisms for therapeutic or diagnostic purposes, the microballoons being non-coalescent, dry and instantly dispersible in said liquid carrier, the polymeric membrane having a thickness between 50 and 500 nm.
Moreover, although the present microspheres can generally be made relatively short-lived, i.e. susceptible to biodegradation to cope with the foregoing metabolization problems by using selected types of polymers, this feature (which is actually controlled by the fabrication parameters) is not a commercial drawback because either the microballoons can be stored and shipped dry, a condition in which they are stable indefinitely, or the membrane can be made substantially impervious to the carrier liquid, degradation starting to occur only after injection. In the first case, the microballoons supplied in dry powder form are simply admixed with a proportion of an aqueous phase carrier before use, this proportion being selected depending on the needs. Note that this is an additional advantage over the prior art products because the concentration can be - 6a -.F
20 ~2~ Za chosen at will and initial values far exceeding the aforementioned 108/m1, i.e. in the range 105 to 101°, are readily accessible. It should be noted that the method of the invention (to be disclosed hereafter) enables to control porosity to a wide extent; hence microballoons with a substantially impervious membrane can be made easily which are stable in the form of suspensions in aqueous liquids and which can be marketed as such also.
Microspheres with membranes of interfacially deposited polymers as defined above, although in the state where they are filled with liquid, are well known in the art. They may - 6b -' 2042722 normally result from the emulsification into droplets (the size of which is controllable in function to the emulsification parameters) of a first aqueous phase in an organic solution of polymer followed by dispersion of this amulsion into a second water phase and subsequent evaporation of the organic solvent.
During evaporation of the volatile solvent, the polymer deposits interfacially at the droplets boundary and forms a microporous membrane which efficiently bounds the encapsulated first aqueous phase from the surrounding second aqueous phase. This technique, although possible, is not preferred in the present invention.
Alternatively, one may emulsify with an emulsifier a hydro-phobic phase in an aqueous phase (usually containing viscosity increasing agents as emulsion stabilizers) thus obtaining an oil-in-water type emulsion of droplets of the hydrophobic phase and thereafter adding thereto a membrane forming polymer dissolved in a volatile organic solvent not miscible with the aqueous phase.
If the polymer is insoluble in the hydrophobic phase) it will deposit interfacially at the boundary between the droplets and the aqueous phase. Otherwise, evaporation of the volatile solvent will lead to the formation of said interfacially depo-sited membrane around the droplets of the emulsified hydrophobic phase. Subsequent evaporation of the encapsulated volatile hydrophobic phase provides water filled microspheres surrounded by interfacially deposited polymer membranes. This technique which is advantageously used in the present invention is disclosed by R. Uno et al, in J. Microencapsulation 1 (1984)) 3-8 and R. Makino et al., Chem. Pharm. Bull. 33 (1984), 1195-l201.
As said before, the size of the droplets can be controlled by changing the emulsification parameters) i.e. nature of emul-sifier (more effective the surfactant, i.e. the larger the hydrophilic to lipophilic balance, the smaller the droplets) and the stirring conditions (faster and more energetic the agita-tion) the smaller the droplets).
In another variant) the interfacial wall forming polymer is dissolved in the starting hydrophobic phase itself; the latter is emulsified into droplets in the aqueous phase and the 20 ~ 27 2 2 membrane around the droplets w111 form upon subsequent evapora-tion of this encapsulated hydrophobic phase. An example of this is reported by J.R. Farnand et al,) Powder Technology 22 (1978), 11-16 who emulsify a solution of polymer (e.g. polyethylene) in naphthalene in boiling water, then after cooling they recover the naphthalene in the form of a suspension of polymer bounded microbeads in cold water and, finally, they remove the naphthalene by subjecting the microbeads to sublimation, whereby 25 ~tm microballoons are produced. Other examples exist, in which a polymer is dissolved in a mixed hydrophobic phase comprising a volatile hydrophobic organic solvent and a water-soluble organic solvent, then this polymer solution is emulsified in a water phase containing an emulsifier, whereby the water-soluble sol-vent disperses into the water phase, thus aiding in the formation of the emulsion of microdroplets of the hydrophobic phase and causing the polymer to precipitate at the interface;
this is disclosed in EP-A-274.961 (H. Fessi).
The aforementioned techniques can be adapted to the pre-paration of air or gas filled microballoons suited for ultra-sonic imaging provided that appropriate conditions are found to control sphere sire in the desired ranges, cell-wall permeabi-lity or imperviousness and replacement of the encapsulated liquid phase by air or a selected gas. Control of overall sphere sire is obviously important to adapt the microballoons to use purposes, i.e. in,~ection or oral intake. The siee conditions for in,~ection (about 0.5 - 10 pm average sire) have been discussed previously. For oral application) the range can be much wider, being considered that echogenicity increases with sire; hence microballoons in several sire ranges between say 1 and 1000 ~tm can De used depending on the needs and provided the membrane is elastic enough not to break during transit in the stomach and intestine. Control of cell-wall permeability is important to ensure that Infiltration by the in~ectable aqueous carrier phase is absent or slow enough not to impair the echographic measurements but) in cases, still substantial to ensure relatively fast after-test biodegradability, l.e. ready metaboli-2ation of the suspension by the organism. Also the microporous .__ structure of the microballoons envelope (pores of a few nm to a few hundreds of nm or more for microballoons envelopes of thickness ranging from 50-500 nm) is a factor of resiliency, i.e. the microspheres can readily accept pressure variations without breaking. The preferred range of pore sizes is about 50-2000 nm.
The conditions for achieving these results are met by using a method for making air or gas filled microballoons usable as suspensions in a carrier liquid for oral, rectal and urethral applications, or for injections into living organisms, said method comprising the steps of:
(1) emulsifying a hydrophobic organic phase into a water phase so as to obtain droplets of said hydrophobic phase as an oil-in-water emulsion in said water phase:
(2) adding to said emulsion a solution of at least one polymer in a volatile solvent insoluble in the water phase, so that a layer of said polymer will form around said droplets (3) evaporating said volatile solvent so that the polymer will deposit by interfacial precipitation around the droplets which then form beads with a core of said hydrophobic phase encapsulated by a membrane of said polymer, said beads being in suspension in said water phase and (4) subjecting said suspension to reduced pressure under conditions such that said encapsulated hydrophobic phase is removed by evaporation; wherein said hydrophobic phase is selected so that it evaporates substantially simultaneously with the water phase and is replaced by air or gas, whereby dry, free flowing, readily dispersible microballoons are obtained.
One factor which enables to control the permeability of the microballoons membrane is the rate of evaporation of the hydrophobic phase relative to that of water in step (4) of the method, e.g., under conditions of freeze drying. For instance if the evaporation in is carried out between about -40 and 0°C, and hexane is used as the hydrophobic phase, polystyrene being the interfacially deposited polymer, beads with relatively large pores are obtained: this is so because the vapour pressure of the hydrocarbon in the chosen temperature range is significantly greater than that of water, which means that the pressure difference between the inside and outside of the spheres will tend to increase the size of the pores in the spheres membrane through which the inside material will be evaporated. In contrast, using cyclooctane as the hydrophobic phase (at -17°C the vapour pressure is the same as that of water) will provide beads with very tiny pores because the difference of pressures - 9a -between the inside and outside of the spheres during evaporation is minimized.
Depending on degree of porosity the microballoons of this invention can be made stable in an aqueous carrier from several hours to several months and give reproducible echographic signals for a long period of time. Actually, depending on the polymer selected, the membrane of the microballoons can be made substantially impervious when suspended in carrier liquids of appropriate osmotic properties, i.e. containing solutes in appropriate concentrations. It should be noted that the existence of micropores in the envelope of the microballoons of the present invention appears to be also related with the - 9b -~. :_:
l~ 20 Q27 22 echographic response, i.e.) a11 other factors being constant, microporous vesicles provide more efficient echographic signal than corresponding non-porous vesicles. The reason is not known but it can be postulated that when a gas is in resonance in a closed structure, the damping properties of the latter may be different if it is porous or non-porous.
Other non water soluble organic solvents which have a vapour pressure of the same order of magnitude between about -!0°C and 0°C are convenient as hydrophobic solvents in this invention. These include hydrocarbons such as for instance n-octane, cyclooctane) the dimethyicyclohexanes, ethyl-cyclo-hexane, 2-, 3- and 4-aethyl-heptane) 3-ethyl-hexane, toluene, xylene) 2-methyl-2-heptane, 2,2,3,3-tetramethylbutane and the like. Esters such as propyl and isopropyl butyrate and isobuty-rate) butyl-formats and the like, are also convenient in this range. Another advantage of freese drying is to operate under reduced pressure of a gas instead of air) whereby gas filled microballoons will result. Physiologically acceptable gases such as C02, H20, methane, Freon~;~'helium and other rare gases are possible. Gases with radioactive tracer activity can be contemplated.
As the volatile solvent insoluble in water to be used for dissolving the polymer to be precipitated interfacially, one can cite halo-compounds such as CC1,1, CH38r) CH2C12) chloroform, Freon, low boiling esters such as aethyl) ethyl and propyi acetate as well as lower ethers and ketones of low water solubi-lity. When solvents not totally insoluble in water are used, e.g. diethyl-ether) it is advantageous to use, as the aqueous phase, a water solution saturated with acid solvent beforehand.
The aqueous phase in which the hydrophobic phase is emul-sified as an oil-in-water emulsion preferably contains 1-20x by weight of water-soluble hydrophilic coapounds lilts sugars and polymers as stabilisers, e.g. polyvinyl alcohol (PVA)) polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), gelatin) polyglu-tamic acid, albuain) and polysaccharides such as starch, dextran, agar, xanthan and the like. Siailar aqueous phases can be used as the carrier liquid in which the microballoons are .
suspended before use.
Part of this Water-soluble polymer can remain in the envelope of the microballoons or it can be removed by washing the beads before subjecting them to final evaporation of the encapsulated hydrophobic core phase.
The emulsifiers to be used (0.1-5% by weight) to provide the oil-in-water emulsion of the hydrophobic phase in the aqueous phase include most physiologically acceptable emulsi-fiers, for instance egg lecithin or soya bean lecithin, or synthetic lecithins such as saturated synthetic lecithins) for example) dimyristoyl phosphatidyl choline) dipalmitoyl phospha-tidyl choline or distearoyl phosphatidyl choline or unsaturated synthetic lecithins, such as dioleyl phosphatidyl choline or dilinoleyl phosphatidyl choline. Emulsifiers also include sur-factants such as free fatty acids) esters of fatty acids with polyoxyalkylene compounds like polyoxypropylene glycol and polyoxyethylene glycol; ethers of fatty alcohols with polyoxy-alkylene glycols; esters of fatty acids with polyoxyalkylated sorbitan; soaps; glycerol-polyalkylene stearate; glycerol-poly-oxyethylene ricinoleate; homo- and copolymers of polyalkylene glycols; polyethoxylated soya-oil and castor oil as well as hydrogenated derivatives; ethers and esters of sucrose or other carbohydrates with fatty acids, fatty alcohols, these being op-tionally polyoxyalkylated; mono-, di- and triglycerides of satu-rated or unsaturated fatty acids; glycerides or soya-o11 and sucrose.
The polymer which constitutes the envelope or bounding membrane of the in~ectable microballoons can be selected from most hydrophilic, biodegradable physiologically compatible poly-mers. Among such polymers one can cite polysaccharides of low water solubility) polylactides and polyglycolides and their copolysers) copolymers of lactides and lactones such as e-caprolactone, a-valerolactone, polypeptides) and proteins such as gelatin) collagen) globulins and albumins. The great versatility in the selection of synthetic polymers is another advantage of the present invention since, as with allergic patients, one may wish to avoid using microballoons made of natural proteins (albumin, gelatin) like in US-A-4,276,885 or EP-A-324.938. Other suitable polymers include poly-(ortho)esters (see for instance US-A-4,093,709; US-A-4,13l,648; US-A-4,138,344; US-A-4,180,646); polylactic and poiyglycoiic acid and their copoly~era, for instance DEXON (see J. Heller) Biomateriala ~ (l980), 51; poly(DL-lactide-co-d-caprolactone), poly(DL-lactide-co-d-valerolactone), poly(DL-lactide-co-~ -butyrolactone)) polyalkylcyanoacrylates; polyamides, polyhydroxy-butyrate; polydioxanone; poly-S-aminoketonea (Polymer ~ (1982), 1693); polyphoaphasenes (Science ~ (l976)) 1214); and polyanhydridea. References on biodegradable polymers can be found in R. Longer et al., Nacromol. Chem. Phys. ~ (1983), 61-126. Polyamino-acids such as polyglutamic and polyaspartic acids can also be used as well as their derivatives, i.e. partial eaters with lower alcohols or glycols. One useful example of such polymers la poly-(t. butyl-glutamate). Copolymers with other amino-acids such as methionine, leucine, valine) proline, glycine, alamine) etc. are also possible. Recently some novel derivatives of polygiutamic and polyaspartic acid with controlled biodegradability have been reported (see W087/03891;
US 4,888,398 and EP-l30.935. These polyeera (and copolymers with other amino-acids) have forwulne of the following types -(NH-CHA-CO)x(NH-CHX-CO)y where X designates the aide chain of an amino-acid residue and A
is a group of formula -(CH2)nC00RiR2-OCOR (II), with R1 and R2 being H or lower altyls) and R being alkyl or aryl; or R and R1 ere connected together by a substituted or unsubstituted linking member to provide 5- or 6- mesbered rings.
A can also represent groups of formulae:
-(CH2)nC00-CHRiC00R (I) and h ..
-(CH2)nC0(NH-CHX-CO)mNH-CH(COOH)-(CH2)pC00H (III) and corresponding anhydrides. In a11 these formulae n) m and p are lower integers (not exceeding 5) and x and y are also integers selected for having molecular weights not below 5000.
The aforementioned polymers are suitable for caking the microballoons according to the invention and) depending on the nature of substituents R, Rl, R2 and X, the properties of the membrane can be controlled, for instance, strength, elasticity and biodegradability. For instance X can be methyl (alanine), isopropyl (valine), isobutyl (leucine and isoleucine), benzyl (phenylalanine).
Additives can be incorporated into the polymer wall of the microballoons to modify the physical properties such as disper-sibility, elasticity and water permeability. For incorporation in the polymer, the additives can be dissolved in the polymer carrying phase, e.g. the hydrophobic phase to be emulsified in the water phase, whereby they will co-precipitate with the polymer during inter-facial membrane formation.
Among the useful additives, one may cite compounds which can "hydrophobise" the microballoons membrane in order to decrease water permeability, such as fats) waxes and high molecular-weight hydrocarbons. Additives which improve dispersi-bility of the microballoons in the in~ectable liquid-carrier are amphipatic compounds like the phospholipids; they also increase water permeability and rate of biodegradability.
Hon-biodegradable polymers for making microballoons to be used in the digestive tract can be selected from most water-insoluble) physiologically acceptable) bioresistant polymers including polyolefins (polystyrene), acrylic resins (polyacry-lates, polyacrylonitrile), polyesters (polycarbonate), polyure-thanes, polyurea and their copolyuers. ABS (acryl-butadiene-styrene) is a preferred copolymer.
Additives which increase membrane elasticity are the plas-ticizers like isopropyl myristate and the like. Also, very useful additives are constituted by polymers akin to that of the mee~brane itself but with relatively low molecular weight. For __ 2 0 4~ 2 7 2 ~
1 ~!
instance when using copolymers of polylactic/polyglycolic type as the membrane forming materiel, the properties of the membrane can be modified advantageously (enhenced softness and biodegra-dability) by incorporating, as additives) loW molecular weight (1000 to 15,000 Dalton) polyglycolidea or ~polylactides. Also polyethylene glycol of moderate to low Mw (e.g. PEG 2000) is a useful softening additive.
The quantity of additives to be incorporated in the polymer forming the inter-tacially deposited membrane of the present microballoona is extremely variable and depends on the needs. In some cases no additive is used at all; in other cases amounts of additives which may reach about 20% by weight of the polymer are possible'.
The in~ectable microballoons of the present invention can be stored dry in the presence or in the absence of additives to improve conservation and prevent coalescence. As additives, one may select from O.l to 25% by weight of water-soluble physiolo-gically acceptable compounds such as mannitol) galactose) lactose or sucrose or hydrophilic polymers like dextran) xanthan, agar, starch, PVP) poiyglutamic acid) polyvinylalcohol (PVA)) albumin and gelatin. The useful life-time of the microbailoons in the in~ectable liquid carrier phase, i.e. the period during which useful echographic signals are observed, can be controlled to last from a few minutes to several months depending on the needs; this can be done by controlling the porosity of the membrane from substantial imperviousness toward carrier liquids to poroaities having pores of a few nanometers to several hundreds of nanometers. This degree of porosity can be controlled) in addition to properly selecting the membrane forming polymer and polymer additives, by adjusting the evaporation rate and temperature in step (~) of the method and properly selecting the nature o! the compound (or mixture of compounds) constituting the hydrophobic phase, i.e.
the greater the differences in its partial pressure of evapora-tion with that of the water phase, the coarser the pores in the microballoons membrane will be. Of course, this control by se-lection of the hydrophobic phase can be further refined by the 204~'~22 choice of stabilizers and by ad,~usting the concentration thereof in order to control the rate of water evaporation during the forming of the microballoons. A11 these changes can easily be made by skilled ones without exercizing inventiveness and need not be further discussed.
It should be remarked that although the microballoons of this invention can be marketed in the dry state, more parti-cularly when they are designed with a limited life time after in,~ection, it may be desirable to also sell ready preparations, i.e. suspensions of microballoons in an aqueous liquid carrier ready for in,~ection or oral administration. This requires that the membrane of the microballoons be substantially impervious (at least for several months or more) to the carrier liquid. It has been shown in this description that such conditions can be easily achieved with the present method by properly selecting the nature of the polymer and the interfacial deposition parameters. Actually parameters have been found (for instance using the polyglutamic polymer (where A is the group of formula II) and cyclooctane as the hydrophobic phase) such that the porosity of the membrane after evaporation of the hydrophobic phase is so tenuous that the microballoons are substantially impervious to the aqueous carrier liquid in which they are suspended.
A preferred administrable preparation for diagnostic purposes comprises a suspension in buffered or unbuffered saline (0.9% aqueous NaCl; buffer 10 wM tris-HC1) containing 108-1010 vesicles/ml. This can be prepared mainly according to the directions of the Examples below, preferably Examples 3 and 4, using poly-(DL-lactide) polymers from the Company Boehringer, Ingelheim) Germany.
The following Examples illustrate the invention practically.
Example 1 One gram of polystyrene was dissolved in 19 g of liquid naphthalene at 100°C. This naphthalene solution was emulsified at 90-95°C into 200 ml of a water solution of polyvinyl alcohol ib 20 427 22 (PVA) (4% by weight) containing 0.1X of Tween-40 eaulsifier. The eaulsifying head vas a Polytron PT-3000 at about 10,000 rpa.
Then the eaulaion vas diluted under agitation with 500 al of the aaae aqueous phase at 15°C whereby the naphthalene droplets solidified into Deads of lean than 50 Vita as ascertained by passing through a 50 Vita aeah screen. The suspension was centrifugated under l000 g and the beads were washed with water and recentrifugated. This step vas repeated twice.
The beads were reauapended in 100 al of water with 0.8 g of dissolved lactose and the suspension was frown into a block at -30°C. The block was thereafter evaporated under about 0.5-2 Torr between about -20 and -10°C. Air filled aicroballoons of average sire 5-10 ua and controlled porosity were thus obtained which gave an echographic signal at 2.25 and 7.5 MHs after being dispersed in water (3% dispersion by weight). The stability of the aicroballoons in the dry state was effective for an indefinite period of tine; once suspended in an aqueous carrier liquid the useful life-tine for echography was about 30 sin or sore. Polystyrene being non-biodegradable, this aateriai was not favored for infection echography but was useful for digestive tract investigations. This Exaaple clearly establishes the feasibility of the aethod of the invention.
Exaanle 2 A 50i50 copolyAer aixture (0.3 g) of DL-lactide and glycolide (Du Pont Me.d.iaorb) and 16 ag of egg-lecithin were dissolved in 7.5 al of CHC13 to give solution (1).
A solution (2) containing 20 ag of paraffin-wax (M.P. 54-56°C) in 10 al of cyclooctane (M.P. 10-13 °) was prepared and eaulaified in 150 al of a water solution (0.13% by weight) of Pluronic F-108 (a block copolyaer of ethylene oxide and propy-lene oxide) containing also 1.2 g of CHC13. Eaulsification vas carried out at rooa teaperature for 1 sin with a Polytron head at 7000 rpa. Then solution (1) was added under agitation (7000 rpa) and) after about 30-60 $ec, the eaulsifier head vas replaced by a helical agitator (500 rpa) and stirring vas conti-nued for about 3 hrs at rooa teaperature (22°C). The suspension 1~ 20 ~z~ 22 was passed through a 50 ~tm screen and frosen to a block which was subsequently evaporated between -20 and 0°C under high-vacuum (catching trap -60 to -80°C). There were thus obtained 0.264 g (88%) of air-filled microballoons stable in the dry state.
Suspensions of said microballoons in water (no stabilisers) gave a strong echographic signal for at least one hour. After infection in the organism, they biodegraded in a few days.
Example 3 A solution was made using 200 ml of tetrahydrofuran (THF), 0.8 g of a 50i50 DL-lactide/glycolide copolymer (Boehringer AG), 80 mg of egg-lecithin, 64 mg of paraffin-wax and 4 ml of octane.
This solution was emulsified by adding slowly into 400 ml of a 0.1% aqueous solution of Pluronic F-l08 under helical agitation (500 r.p.m.). After stirring for 15 min, the milky TM
dispersion was evaporated under 10-12 Torr 25°C in a rotavapor until its volume was reduced to about 400 ml. The dispersion was sieved on a 50 ~tm grating) then it was frosen to -40°C and freese-dried under about 1 Torr. The residue, 1.32 g of very fine powder, was taken with 40 ml of distilled water which provided, after 3 min of manual agitation, a very homogeneous dispersion of microballoons of average alas 4.5 ~Cm as measured TM
using a particle analyser (Nastersiser from Malvern). The concentration of microballoons (Couiter Counter) was about 2 x 109/m1. This suspension gave strong echographic signals which persisted for about 1 hr.
If in the present example, the additives to the membrane polymer are omitted) i.e. there is used only 800 mg of the lactide/glycoiide copolyAer in the THF/octane solution) a dramatic decrease in cell-wall permeability is observed, the echographic signal of the dispersion in the aqueous carrier not being significantly attenuated after 3 days.
Using intermediate quantities of additives provided beads with controlled intermediate porosity and life-time.
EXBmDle 4 There was used in this Example a polymer of formula defined in claim 8 in which the side group has formula (II) where R1 and R2 are hydrogen and R is tert.butyi. The preparation of this polymer (defined as poly-POMEG) is described in !JS-A-4,888,398.
The procedure was like in Example 3, using 0.1 g poly-POMEG, 70 ml of THF, 1 ml of cyclooctane and 100 ml of a 0.1%
aqueous solution of Pluronic'~' F-108. No lecithin or high-molecular weight hydrocarbon was added. The milky emulsion was evaporated at 27C/10 Torr until the residue was about 100 ml, then it was screened on a 50 ~tm mesh and frosen. Evaporation of the frown block was carried out (0.5-1 Torr) until dry. The yield was 0.18 g because of the presence of the surfactant. This was dispersed in l0 ml of distilled water and counted with a Coulter Counter. The measured concentration was found to be 1,43 x l09 microcapsules/ml, average sire 5.21 ~tm as determined with a particle analyser (Mastersiser from Malvern). The dispersion was diluted 100 x, i.e. to give about 1.5 x 107 microspheres/ml and measured for echogenicity. The ampiitude of the echo signal was 5 times greater at 7.5 MHs than at 2.25 MHs.
These signals were reproducible for a long period of time.
Echogenicity measurements were performed with a pulse-echo system consisting of a plexigiaa specimen holder (diameter 30 mm) with a 20 ~tm thick Mylar acoustic window, a transducer holder immersed in a constant temperature water bath) a puiser-receiver (Accutron M3010JS) with an external pre-amplifier with a fixed gain of 40 dB and an internal amplifier with gain ad~ustabie from -40 to +40 dB and interchangeable 13 mm unfocused transducers. A 10 MHs low-pass filter was inserted in the receiving part to improve the signal to noise ratio. The A/D
board in the IBM PC was a Sonotek STR 832. Measurements were carried out at 2.25, 3.5, 5 and 7.5 MHs.
If in the present Example, the polymer used is replaced by lactic-lactone copolymers, the lactones being ~ -butyrolactone, a-valerolactone or e-caprolactone (see Fukusaki et al., J.
Biomedical Mater. Res. 25 (l991), 315-328), similar favorable results were obtained. Also in a similar context, polyalkylcyano-i9 2042722 acrylatea and particularly a 90:10 copolymer poly(DL-lactide-co-glycolide) gave satisfactory results. Finally, a preferred poly-mer is a poly(DL-lactide) from the Company Boehringer-Ingelheim sold under the trademark "Resomer R-206" or Resomer R-207.
Example Two-dimensional echocardiography was performed using an Acuson-128 apparatus with the preparation of Example 4 (l.43 x 109/m1) in an experimental dog following peripheral vein infection of 0.1-2 ml of the dispersion. After normally expected contrast enhancement imaging of the right heart, intense and persistent signal enhancement of the left heart with clear outlining of the endocardium was observed) thereby confirming that the microballoons made with poly-POMEG (or at least a significant part of them) were able to cross the pulmonary capillary circulation and to remain in the blood-stream for a time sufficient to perform efficient echographic analysis.
In another series of experiments, persistent enhancement of the Doppler signal from systemic arteries and the portal vein vas observed in the rabbit and in the rat following peripheral vein infection of 0.5-2 ml of a preparation of microballoons prepared as disclosed in Example 4 but using poly(DL-lactic acid) as the polymer phase. The composition used contained 1.9 x 108 veaiclea/ml.
Another composition prepared also according to the direc-tions of Example 4 was achieved using poly(tert.butyl-glutamate). This composition (0.5 ml) at dilution of 3.4 x l08 microballoona/mi was infected in the portal vein of rata and gave persistent contrast enhancement of the liver parenchyma.
Examvle 6 A microballoon suspension (l.l x 109 vesicles/mi) was prepared as disclosed in Example 1 (resin = polystyrene). One ml of this suspension vas diluted with 100 ml of 300 mM mannitol solution and 7 ml of the resulting dilution vas administered intragaatricaliy to a laboratory rat. The animal was examined with an Acuaon-l28 apparatus for 2-dimensional echography 20 ~2~ Za imaging of the digestive tract Which clearly shoaled the single loops of the small intestine and of the colon.
Claims (49)
1. Microballoons in a size range between 0.5 to 1,000 µm bounded by a soft, elastic, 50 to 500 nm thick polymer membrane filled with air or a gas, said microballoons being suitable, when in the form of suspensions in an aqueous liquid carrier, for administration to human or animal patients for therapeutic or diagnostic applications, the membrane being temporarily deformable under pressure variations and made from synthetic, resilient and interfacially depositable polymer.
2. Air or gas filled microballoons comprising an elastic interfacial synthetic polymeric membrane, adapted to form, with a physiologically acceptable aqueous liquid carrier, stable aqueous suspensions capable of being taken orally, rectally and urethrally, or injectable into living organisms for therapeutic or diagnostic purposes, the microballoons being non-coalescent, dry and instantly dispersible in said liquid carrier, the polymeric membrane having a thickness between 50 and 500 nm.
3. Air or gas filled microballoons in a size range between 0.5 to 1,000 µn comprising an elastic, interfacial, synthetic, 50 and 500 nm thick polymeric membrane, adapted to form, with a physiologically acceptable aqueous liquid carrier, stable aqueous suspensions capable of being taken orally, rectally and urethrally, or injectable into living organisms for therapeutic or diagnostic purposes, the microballoons being non-coalescent, dry and instantly dispersible in said liquid carrier.
4. The microballoons of any one of claims 1 through 3, adapted for echography imaging.
5. The microballoons of any one of claims 1 through 4, having a size in the 0.5 - 10 µm range suitable for injection into the bloodstream of living beings wherein the membrane is either impervious or permeable to bioactive liquids for increasing the rate of biodegradation.
6. The microballoons of any one of claims 1 through 5, wherein the polymer membrane is porous and has a porosity ranging from a few nanometers to several thousands of nanometers.
7. The microballoons of any one of claim 6, wherein said porosity ranges from 50 - 2,000 nm.
8. The microballoons of any one of claims 1 through 7, wherein the polymer of the membrane is a biodegradable polymer selected from polysaccharides, polyamino-acids, polylactides and polyglycolides and their copolymers, copolymers of lactides and lactones, polypeptides, poly-(ortho)esters, polydioxanone, poly-.beta.-aminoketones, polyphosphazenes, polyanhydrides and polyalkyl(cyano)acrylates.
9. The microballoons of any one of claims 1 through 8, wherein the membrane polymer is selected from polyglutamic and polyaspartic acid derivatives and their copolymers with other amino acids.
10. The microballoons of claim 9, wherein the polyglutamic and polyaspartic acid derivatives are selected from esters and amides involving the carboxylated side functions thereof, said side functions having formulae (CH2)n COO-CHR1COOR (I), or (CH2)n COOCR1R2-O-COR (II), or (CH2)n CO(NH-CHX-CO)m NHCH(COOH)-(CH2)p COOH (III), wherein R is an alkyl or aryl substituent; R1 and R2 are H
or lower alkyls, or R and R1 are connected together by a substituted or unsubstituted linking member to form a 5- or 6-membered ring; n is 1 or 2; p is 1, 2 or 3; m is an integer from 1 to 5; and X is a side chain of an amino acid residue.
or lower alkyls, or R and R1 are connected together by a substituted or unsubstituted linking member to form a 5- or 6-membered ring; n is 1 or 2; p is 1, 2 or 3; m is an integer from 1 to 5; and X is a side chain of an amino acid residue.
11. The microballoons of claim 1, wherein the membrane polymer contains additives to control the degree of elasticity and the size and density of pores of said membrane polymer for permeability control.
12. The microballoons of claim 11, wherein said additives comprise plasticizers, amphipathic substances and hydrophobic compounds.
13. The microballoons of claim 12, wherein the plasticizers comprise isopropyl myristate and glyceryl monostearate to control flexibility, the amphipathic substances comprise surfactants and phospholipids to control permeability by increasing porosity and the hydrophobic compounds comprise high molecular weight hydrocarbons to reduce porosity.
14. The microballoons of claim 12, wherein the amphipathic substances comprise lecithins and the hydrophobic compounds comprise paraffin waxes.
15. The microballoons of claim 11, wherein the additives comprise polymers having a molecular weight in the range of 1,000 to 15,000 daltons to control softness and resiliency of the microballoon membrane.
16. The microballoons of claim 15, wherein the low molecular weight polymer additives are selected from polylactides, polyglycolides, polyalkylene glycols and polyols.
17. The microballoons of claim 16, wherein the polyalkylene glycols are selected from polyethylene glycol and polypropylene glycol and the polyol is polyglycerol.
18. The microballoons of any one of claims 1 through 3, having a size up to about 1,000 µm suitable for oral, rectal and urethral applications, wherein the membrane polymer is not biodegradable in the digestive tract and is impervious to biological liquids.
19. The microballoons of claim 18, wherein the polymer is selected from polyolefins, polyacrylates, polyacrylonitrile, non-hydrolyzable polyesters, polyurethanes and polyureas.
20. An injectable aqueous suspension of microballoons according to any one of claims 1-7, 10, 12-17 and 19, wherein the microballoons are present in a concentration of about 10 6 to 10 10 microballoons/ml, said suspension being stable for at least thirty days.
21. An injectable aqueous suspension of microballoons according to claim 8, wherein the microballoons are present in a concentration of about 10 6 to 10 10 microballoons/ml, said suspension being stable for at least thirty days.
22. An injectable aqueous suspension of microballoons according to claim 9, wherein the microballoons are present in a concentration of about 10 6 to 10 10 microballoons/ml, said suspension being stable for at least thirty days.
23. An injectable aqueous suspension of microballoons according to claim 11, wherein the microballoons are present in a concentration of about 10 6 to 10 10 microballoons/ml, said suspension being stable for at least thirty days.
24. An injectable aqueous suspension of microballoons according to claim 18, wherein the microballoons are present in a concentration of about 10 6 to 10 10 microballoons/ml, said suspension being stable for at least thirty days.
25. The injectable aqueous suspension of microballoons according to claim 20, wherein the microballoons are bounded by a membrane of interfacially deposited DL-lactide polymer defined by the commercial name of Resomer~.
26. The injectable aqueous suspension of microballoons according to any one of claims 21-24, wherein the microballoons are bounded by a membrane of interfacially deposited DL-lactide polymer defined by the commercial name of Resomer~.
27. A method for making air or gas filled microballoons usable as suspensions in a carrier liquid for oral, rectal and urethral applications, or for injections into living organisms, said method comprising the steps of:
(1) emulsifying a hydrophobic organic phase into a water phase so as to obtain droplets of said hydrophobic phase as an oil-in-water emulsion in said water phase (2) adding to said emulsion a solution of at least one polymer in a volatile solvent insoluble in the water phase, so that a layer of said polymer will form around said droplets:
(3) evaporating said volatile solvent so that the polymer will deposit by interfacial precipitation around the droplets which then form beads with a core of said hydrophobic phase encapsulated by a membrane of said polymer, said beads being in suspension in said water phase;
and (4) subjecting said suspension to reduced pressure under conditions such that said encapsulated hydrophobic phase is removed by evaporation;
wherein said hydrophobic phase is selected so that it evaporates substantially simultaneously with the water phase and is replaced by air or gas, whereby dry, free flowing, readily dispersible microballoons are obtained.
(1) emulsifying a hydrophobic organic phase into a water phase so as to obtain droplets of said hydrophobic phase as an oil-in-water emulsion in said water phase (2) adding to said emulsion a solution of at least one polymer in a volatile solvent insoluble in the water phase, so that a layer of said polymer will form around said droplets:
(3) evaporating said volatile solvent so that the polymer will deposit by interfacial precipitation around the droplets which then form beads with a core of said hydrophobic phase encapsulated by a membrane of said polymer, said beads being in suspension in said water phase;
and (4) subjecting said suspension to reduced pressure under conditions such that said encapsulated hydrophobic phase is removed by evaporation;
wherein said hydrophobic phase is selected so that it evaporates substantially simultaneously with the water phase and is replaced by air or gas, whereby dry, free flowing, readily dispersible microballoons are obtained.
28. The method of claim 27, wherein said polymer is dissolved in said hydrophobic phase, so that steps (2) and (3) can be omitted and the polymer membrane will form by interfacial precipitation during step (4).
29. The method of claim 27, wherein evaporation of said hydrophobic phase in step (4) is performed at a temperature where the partial vapour pressure of said hydrophobic phase is of the same order as that of water vapour.
30. The method of claim 27, wherein said evaporation of step (4) is carried out under freeze-drying conditions.
31. The method of claim 30, wherein freeze-drying is effected at temperatures of from -40°C to 0°C.
32. The method of claim 27 or 29, wherein the hydrophobic phase is selected from organic compounds having a vapour pressure of about 1 Torr at a temperature comprised in the interval of about -40°C to 0°C.
33. The method of claims 27 or 28, wherein the aqueous phase comprises, dissolved, from about 1 to 20% by weight of stabilizers comprising a hydrophilic compound selected from sugars, PVA, PVP, gelatin, starch, dextran, polydextrose and albumin.
34. The method of claim 28, wherein additives to control the degree of permeability of the microballoons membrane are added to the hydrophobic phase, the rate of biodegradability of the polymer after injecting the microballoons into living organisms being a function of said degree of permeability.
35. The method of claim 34, wherein said additives comprise hydrophobic solids, the presence of which in the membrane polymer of the microballoons will reduce permeability toward aqueous liquids.
36. The method of claim 35, wherein the hydrophobic solids are selected from fats, waxes and high molecular weight hydrocarbons.
37. The method of claim 34, wherein said additives comprise amphipathic compounds or polymers having a molecular weight in the range of 1,000 to 15,000 daltons, the presence of which in the membrane polymer will increase permeability of the microballoons to aqueous liquids.
38. The method of claim 37, wherein the amphipathic compound is a phospholipid.
39. The method of claim 28, wherein the hydrophobic phase subjected to emulsification in said water phase also contains a water-soluble solvent which, upon being diluted into said water phase during emulsification, will aid in reducing the size of droplets and induce interfacial precipitation of the polymer before step (4) is carried out.
40. Use of microballoons of any one of claims 1-7, 10, 12-17 and 19, for ultrasonic echography imaging of human or animal body.
41. Use of microballoons of claim 8, for ultrasonic echography imaging of human or animal body.
42. Use of microballoons of claim 9, for ultrasonic echography imaging of human or animal body.
43. Use of microballoons of claim 11, for ultrasonic echography imaging of human or animal body.
44. Use of microballoons of claim 18, for ultrasonic echography imaging of human or animal body.
45. Use of microballoons of any one of claims 1-7, 10, 12-17 and 19, for ultrasonic echography imaging of liver.
46. Use of microballoons of claim 8, for ultrasonic echography imaging of liver.
47. Use of microballoons of claim 9, for ultrasonic echography imaging of liver.
48. Use of microballoons of claim 11, for ultrasonic echography imaging of liver.
49. Use of microballoons of claim 18, for ultrasonic echography imaging of liver.
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EP90810367.4 | 1990-05-18 | ||
EP90810367 | 1990-05-18 |
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CA002042722A Expired - Lifetime CA2042722C (en) | 1990-05-18 | 1991-05-16 | Polymeric gas or air filled microballoons usable as suspensions in liquid carriers for ultrasonic echography |
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US (7) | US5711933A (en) |
EP (1) | EP0458745B2 (en) |
JP (1) | JP2897190B2 (en) |
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Families Citing this family (274)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6088613A (en) | 1989-12-22 | 2000-07-11 | Imarx Pharmaceutical Corp. | Method of magnetic resonance focused surgical and therapeutic ultrasound |
US6551576B1 (en) | 1989-12-22 | 2003-04-22 | Bristol-Myers Squibb Medical Imaging, Inc. | Container with multi-phase composition for use in diagnostic and therapeutic applications |
US6146657A (en) | 1989-12-22 | 2000-11-14 | Imarx Pharmaceutical Corp. | Gas-filled lipid spheres for use in diagnostic and therapeutic applications |
US5580575A (en) * | 1989-12-22 | 1996-12-03 | Imarx Pharmaceutical Corp. | Therapeutic drug delivery systems |
US5776429A (en) | 1989-12-22 | 1998-07-07 | Imarx Pharmaceutical Corp. | Method of preparing gas-filled microspheres using a lyophilized lipids |
US5469854A (en) | 1989-12-22 | 1995-11-28 | Imarx Pharmaceutical Corp. | Methods of preparing gas-filled liposomes |
US5585112A (en) | 1989-12-22 | 1996-12-17 | Imarx Pharmaceutical Corp. | Method of preparing gas and gaseous precursor-filled microspheres |
US6001335A (en) | 1989-12-22 | 1999-12-14 | Imarx Pharmaceutical Corp. | Contrasting agents for ultrasonic imaging and methods for preparing the same |
US20020150539A1 (en) * | 1989-12-22 | 2002-10-17 | Unger Evan C. | Ultrasound imaging and treatment |
US5542935A (en) * | 1989-12-22 | 1996-08-06 | Imarx Pharmaceutical Corp. | Therapeutic delivery systems related applications |
US5922304A (en) | 1989-12-22 | 1999-07-13 | Imarx Pharmaceutical Corp. | Gaseous precursor filled microspheres as magnetic resonance imaging contrast agents |
US5352435A (en) * | 1989-12-22 | 1994-10-04 | Unger Evan C | Ionophore containing liposomes for ultrasound imaging |
US5445813A (en) * | 1992-11-02 | 1995-08-29 | Bracco International B.V. | Stable microbubble suspensions as enhancement agents for ultrasound echography |
US20040208826A1 (en) * | 1990-04-02 | 2004-10-21 | Bracco International B.V. | Ultrasound contrast agents and methods of making and using them |
IN172208B (en) | 1990-04-02 | 1993-05-01 | Sint Sa | |
US6989141B2 (en) * | 1990-05-18 | 2006-01-24 | Bracco International B.V. | Ultrasound contrast agents and methods of making and using them |
USRE39146E1 (en) | 1990-04-02 | 2006-06-27 | Bracco International B.V. | Long-lasting aqueous dispersions or suspensions of pressure-resistant gas-filled microvesicles and methods for the preparation thereof |
US7083778B2 (en) | 1991-05-03 | 2006-08-01 | Bracco International B.V. | Ultrasound contrast agents and methods of making and using them |
US20010024638A1 (en) * | 1992-11-02 | 2001-09-27 | Michel Schneider | Stable microbubble suspensions as enhancement agents for ultrasound echography and dry formulations thereof |
US6613306B1 (en) | 1990-04-02 | 2003-09-02 | Bracco International B.V. | Ultrasound contrast agents and methods of making and using them |
US5578292A (en) | 1991-11-20 | 1996-11-26 | Bracco International B.V. | Long-lasting aqueous dispersions or suspensions of pressure-resistant gas-filled microvesicles and methods for the preparation thereof |
AU636481B2 (en) * | 1990-05-18 | 1993-04-29 | Bracco International B.V. | Polymeric gas or air filled microballoons usable as suspensions in liquid carriers for ultrasonic echography |
US20030194376A1 (en) * | 1990-05-18 | 2003-10-16 | Bracco International B.V. | Ultrasound contrast agents and methods of making and using them |
US5562099A (en) * | 1990-10-05 | 1996-10-08 | Massachusetts Institute Of Technology | Polymeric microparticles containing agents for imaging |
US5487390A (en) * | 1990-10-05 | 1996-01-30 | Massachusetts Institute Of Technology | Gas-filled polymeric microbubbles for ultrasound imaging |
US5370901A (en) | 1991-02-15 | 1994-12-06 | Bracco International B.V. | Compositions for increasing the image contrast in diagnostic investigations of the digestive tract of patients |
GB9106673D0 (en) * | 1991-03-28 | 1991-05-15 | Hafslund Nycomed As | Improvements in or relating to contrast agents |
GB9106686D0 (en) † | 1991-03-28 | 1991-05-15 | Hafslund Nycomed As | Improvements in or relating to contrast agents |
US5205290A (en) | 1991-04-05 | 1993-04-27 | Unger Evan C | Low density microspheres and their use as contrast agents for computed tomography |
US5874062A (en) * | 1991-04-05 | 1999-02-23 | Imarx Pharmaceutical Corp. | Methods of computed tomography using perfluorocarbon gaseous filled microspheres as contrast agents |
GB9107628D0 (en) * | 1991-04-10 | 1991-05-29 | Moonbrook Limited | Preparation of diagnostic agents |
US5993805A (en) * | 1991-04-10 | 1999-11-30 | Quadrant Healthcare (Uk) Limited | Spray-dried microparticles and their use as therapeutic vehicles |
JP3319754B2 (en) * | 1991-06-03 | 2002-09-03 | ニユコメド・イメージング・アクシエセルカペト | Improvements in or on contrast agents |
GB9116610D0 (en) * | 1991-08-01 | 1991-09-18 | Danbiosyst Uk | Preparation of microparticles |
NZ244147A (en) † | 1991-09-03 | 1994-09-27 | Hoechst Ag | Echogenic particles which comprise a gas and at least one shaping substance, and their use as diagnostic agents |
US5409688A (en) * | 1991-09-17 | 1995-04-25 | Sonus Pharmaceuticals, Inc. | Gaseous ultrasound contrast media |
US6875420B1 (en) | 1991-09-17 | 2005-04-05 | Amersham Health As | Method of ultrasound imaging |
MX9205298A (en) * | 1991-09-17 | 1993-05-01 | Steven Carl Quay | GASEOUS ULTRASOUND CONTRASTING MEDIA AND METHOD FOR SELECTING GASES TO BE USED AS ULTRASOUND CONTRASTING MEDIA |
US6723303B1 (en) | 1991-09-17 | 2004-04-20 | Amersham Health, As | Ultrasound contrast agents including protein stabilized microspheres of perfluoropropane, perfluorobutane or perfluoropentane |
HU218018B (en) * | 1991-09-17 | 2000-05-28 | Sonus Pharmaceuticals Inc. | Gaseous ultrasound contrast media and method for selecting gases for use as ultrasound contrast media |
GB9200388D0 (en) * | 1992-01-09 | 1992-02-26 | Nycomed As | Improvements in or relating to contrast agents |
GB9200391D0 (en) * | 1992-01-09 | 1992-02-26 | Nycomed As | Improvements in or relating to contrast agents |
IL104084A (en) * | 1992-01-24 | 1996-09-12 | Bracco Int Bv | Long-lasting aqueous suspensions of pressure-resistant gas-filled microvesicles their preparation and contrast agents consisting of them |
US5674468A (en) * | 1992-03-06 | 1997-10-07 | Nycomed Imaging As | Contrast agents comprising gas-containing or gas-generating polymer microparticles or microballoons |
CZ284844B6 (en) * | 1992-03-06 | 1999-03-17 | Nycomed Imaging A/S | Contrasting agent |
GB9204918D0 (en) | 1992-03-06 | 1992-04-22 | Nycomed As | Chemical compounds |
DE4219723A1 (en) * | 1992-06-13 | 1993-12-16 | Schering Ag | Microparticles, processes for their production and their use in diagnostics |
US6383470B1 (en) | 1992-09-26 | 2002-05-07 | Thomas Fritzsch | Microparticle preparations made of biodegradable copolymers |
DE4232755A1 (en) * | 1992-09-26 | 1994-03-31 | Schering Ag | Microparticle preparations made from biodegradable copolymers |
GB9221329D0 (en) * | 1992-10-10 | 1992-11-25 | Delta Biotechnology Ltd | Preparation of further diagnostic agents |
US5558855A (en) * | 1993-01-25 | 1996-09-24 | Sonus Pharmaceuticals | Phase shift colloids as ultrasound contrast agents |
IL108416A (en) | 1993-01-25 | 1998-10-30 | Sonus Pharma Inc | Phase shift colloids as ultrasound contrast agents |
WO1994016739A1 (en) * | 1993-01-25 | 1994-08-04 | Sonus Pharmaceuticals, Inc. | Phase shift colloids as ultrasound contrast agents |
US5855865A (en) * | 1993-07-02 | 1999-01-05 | Molecular Biosystems, Inc. | Method for making encapsulated gas microspheres from heat denatured protein in the absence of oxygen gas |
BR9406993A (en) * | 1993-07-02 | 1996-09-10 | Molecular Biosystems Inc | Microspheres of insoluble gases encapsulated with protein and their preparation and use as ultrasonic imaging agents |
DK0711179T3 (en) | 1993-07-30 | 2005-02-14 | Imcor Pharmaceutical Co | Stabilized ultrasound microbubble compositions |
US5798091A (en) | 1993-07-30 | 1998-08-25 | Alliance Pharmaceutical Corp. | Stabilized gas emulsion containing phospholipid for ultrasound contrast enhancement |
GB9318288D0 (en) * | 1993-09-03 | 1993-10-20 | Nycomed Imaging As | Improvements in or relating to contrast agents |
WO1995007072A2 (en) * | 1993-09-09 | 1995-03-16 | Schering Aktiengesellschaft | Active principles and gas containing microparticles |
US7083572B2 (en) * | 1993-11-30 | 2006-08-01 | Bristol-Myers Squibb Medical Imaging, Inc. | Therapeutic delivery systems |
KR100295173B1 (en) * | 1993-12-15 | 2001-09-17 | 엔. 토모브 | Gas Mixtures Useful as Ultrasonic Contrast Media |
CA2189366A1 (en) * | 1994-05-03 | 1995-11-09 | Kenneth J. Widder | Composition for ultrasonically quantitating myocardial perfusion |
US5730955A (en) * | 1994-08-02 | 1998-03-24 | Molecular Biosystems, Inc. | Process for making gas-filled microspheres containing a liquid hydrophobic barrier |
US5562893A (en) * | 1994-08-02 | 1996-10-08 | Molecular Biosystems, Inc. | Gas-filled microspheres with fluorine-containing shells |
US5965109A (en) * | 1994-08-02 | 1999-10-12 | Molecular Biosystems, Inc. | Process for making insoluble gas-filled microspheres containing a liquid hydrophobic barrier |
DE4428589C2 (en) * | 1994-08-12 | 1996-11-07 | Byk Gulden Lomberg Chem Fab | Oral echo contrast agent |
GB9417941D0 (en) * | 1994-09-06 | 1994-10-26 | Nycomed Imaging As | Improvements in or relating to contrast agents |
US5540909A (en) * | 1994-09-28 | 1996-07-30 | Alliance Pharmaceutical Corp. | Harmonic ultrasound imaging with microbubbles |
GB9423419D0 (en) * | 1994-11-19 | 1995-01-11 | Andaris Ltd | Preparation of hollow microcapsules |
US6333021B1 (en) * | 1994-11-22 | 2001-12-25 | Bracco Research S.A. | Microcapsules, method of making and their use |
US6743779B1 (en) | 1994-11-29 | 2004-06-01 | Imarx Pharmaceutical Corp. | Methods for delivering compounds into a cell |
US5830430A (en) | 1995-02-21 | 1998-11-03 | Imarx Pharmaceutical Corp. | Cationic lipids and the use thereof |
DE19510690A1 (en) | 1995-03-14 | 1996-09-19 | Schering Ag | Polymeric nano- and / or microparticles, processes for their production, and use in medical diagnostics and therapy |
US5759539A (en) * | 1995-06-06 | 1998-06-02 | Georgia Research Foundation, Inc. | Method for rapid enzymatic alcohol removal |
US5997898A (en) | 1995-06-06 | 1999-12-07 | Imarx Pharmaceutical Corp. | Stabilized compositions of fluorinated amphiphiles for methods of therapeutic delivery |
US6521211B1 (en) * | 1995-06-07 | 2003-02-18 | Bristol-Myers Squibb Medical Imaging, Inc. | Methods of imaging and treatment with targeted compositions |
US5820850A (en) * | 1995-06-07 | 1998-10-13 | Molecular Biosystems, Inc. | Gas-filled amino acid block co-polymer microspheres useful as ultrasound contrast agents |
US6033645A (en) | 1996-06-19 | 2000-03-07 | Unger; Evan C. | Methods for diagnostic imaging by regulating the administration rate of a contrast agent |
WO1996040277A2 (en) * | 1995-06-07 | 1996-12-19 | Brown University Research Foundation | Spray dried polymeric microparticles containing imaging agents |
US6139819A (en) | 1995-06-07 | 2000-10-31 | Imarx Pharmaceutical Corp. | Targeted contrast agents for diagnostic and therapeutic use |
US6231834B1 (en) | 1995-06-07 | 2001-05-15 | Imarx Pharmaceutical Corp. | Methods for ultrasound imaging involving the use of a contrast agent and multiple images and processing of same |
US5804162A (en) | 1995-06-07 | 1998-09-08 | Alliance Pharmaceutical Corp. | Gas emulsions stabilized with fluorinated ethers having low Ostwald coefficients |
AU1354497A (en) * | 1995-12-21 | 1997-07-14 | Drexel University | Hollow polymer microcapsules and method of producing |
US5611344A (en) * | 1996-03-05 | 1997-03-18 | Acusphere, Inc. | Microencapsulated fluorinated gases for use as imaging agents |
DK0904113T3 (en) * | 1996-03-05 | 2004-08-30 | Acusphere Inc | Microencapsulated fluorinated gases for use as imaging agents |
DE19611769A1 (en) * | 1996-03-14 | 1997-09-18 | Schering Ag | Microparticles, processes for their production and their use in ultrasound diagnostics |
ATE345682T1 (en) | 1996-05-01 | 2006-12-15 | Imarx Pharmaceutical Corp | IN VITRO METHOD FOR INTRODUCING NUCLEIC ACIDS INTO A CELL |
US5874064A (en) | 1996-05-24 | 1999-02-23 | Massachusetts Institute Of Technology | Aerodynamically light particles for pulmonary drug delivery |
US6652837B1 (en) | 1996-05-24 | 2003-11-25 | Massachusetts Institute Of Technology | Preparation of novel particles for inhalation |
US5985309A (en) * | 1996-05-24 | 1999-11-16 | Massachusetts Institute Of Technology | Preparation of particles for inhalation |
US5976501A (en) * | 1996-06-07 | 1999-11-02 | Molecular Biosystems, Inc. | Use of pressure resistant protein microspheres encapsulating gases as ultrasonic imaging agents for vascular perfusion |
US5837221A (en) * | 1996-07-29 | 1998-11-17 | Acusphere, Inc. | Polymer-lipid microencapsulated gases for use as imaging agents |
US6414139B1 (en) | 1996-09-03 | 2002-07-02 | Imarx Therapeutics, Inc. | Silicon amphiphilic compounds and the use thereof |
US6017310A (en) * | 1996-09-07 | 2000-01-25 | Andaris Limited | Use of hollow microcapsules |
US5846517A (en) † | 1996-09-11 | 1998-12-08 | Imarx Pharmaceutical Corp. | Methods for diagnostic imaging using a renal contrast agent and a vasodilator |
DE69737915T2 (en) | 1996-09-11 | 2008-03-13 | Bristol-Myers Squibb Medical Imaging, Inc. | Method of diagnostic imaging of the kidney region using a contrast agent and a vasodilator |
US6068600A (en) * | 1996-12-06 | 2000-05-30 | Quadrant Healthcare (Uk) Limited | Use of hollow microcapsules |
US6537246B1 (en) | 1997-06-18 | 2003-03-25 | Imarx Therapeutics, Inc. | Oxygen delivery agents and uses for the same |
US6143276A (en) | 1997-03-21 | 2000-11-07 | Imarx Pharmaceutical Corp. | Methods for delivering bioactive agents to regions of elevated temperatures |
US6120751A (en) | 1997-03-21 | 2000-09-19 | Imarx Pharmaceutical Corp. | Charged lipids and uses for the same |
US6090800A (en) | 1997-05-06 | 2000-07-18 | Imarx Pharmaceutical Corp. | Lipid soluble steroid prodrugs |
JP2001527547A (en) * | 1997-04-30 | 2001-12-25 | ポイント バイオメディカル コーポレイション | Microparticles useful as ultrasound contrast agents and for drug delivery to the bloodstream |
US20050019266A1 (en) * | 1997-05-06 | 2005-01-27 | Unger Evan C. | Novel targeted compositions for diagnostic and therapeutic use |
US6610764B1 (en) | 1997-05-12 | 2003-08-26 | Metabolix, Inc. | Polyhydroxyalkanoate compositions having controlled degradation rates |
US6867248B1 (en) | 1997-05-12 | 2005-03-15 | Metabolix, Inc. | Polyhydroxyalkanoate compositions having controlled degradation rates |
US6416740B1 (en) | 1997-05-13 | 2002-07-09 | Bristol-Myers Squibb Medical Imaging, Inc. | Acoustically active drug delivery systems |
US6045777A (en) * | 1997-06-30 | 2000-04-04 | Acusphere, Inc. | Method for enhancing the echogenicity and decreasing the attenuation of microencapsulated gases |
JP4841710B2 (en) | 1997-07-04 | 2011-12-21 | ジーイー・ヘルスケア・アクスイェ・セルスカプ | How to select pre-selected small air vesicles from small air vesicular drug products |
US6828357B1 (en) | 1997-07-31 | 2004-12-07 | Metabolix, Inc. | Polyhydroxyalkanoate compositions having controlled degradation rates |
DE69819309T2 (en) * | 1997-08-12 | 2004-07-15 | Bracco Research S.A. | AVAILABLE FORMULATIONS AND THEIR APPLICATION IN MRI |
US6548047B1 (en) | 1997-09-15 | 2003-04-15 | Bristol-Myers Squibb Medical Imaging, Inc. | Thermal preactivation of gaseous precursor filled compositions |
US7637948B2 (en) | 1997-10-10 | 2009-12-29 | Senorx, Inc. | Tissue marking implant |
US8668737B2 (en) | 1997-10-10 | 2014-03-11 | Senorx, Inc. | Tissue marking implant |
US6123923A (en) | 1997-12-18 | 2000-09-26 | Imarx Pharmaceutical Corp. | Optoacoustic contrast agents and methods for their use |
GB9727102D0 (en) * | 1997-12-22 | 1998-02-25 | Andaris Ltd | Microparticles and their therapeutic use |
ES2394953T3 (en) | 1997-12-22 | 2013-02-07 | Metalbolix Inc. | Polyhydroxyalkanoate compositions with controlled degradation rates |
US20010003580A1 (en) | 1998-01-14 | 2001-06-14 | Poh K. Hui | Preparation of a lipid blend and a phospholipid suspension containing the lipid blend |
IT1298269B1 (en) * | 1998-02-18 | 1999-12-20 | Promefarm S R L | USE OF A POLYETHYLENGLYCLE AS A MEANS OF CONTRAST IN ECHOGRAPHY |
US6347241B2 (en) | 1999-02-02 | 2002-02-12 | Senorx, Inc. | Ultrasonic and x-ray detectable biopsy site marker and apparatus for applying it |
US6238677B1 (en) * | 1998-08-18 | 2001-05-29 | The United States Of America As Represented By The Secretary Of Agriculture | Starch microcapsules for delivery of active agents |
US7983734B2 (en) | 2003-05-23 | 2011-07-19 | Senorx, Inc. | Fibrous marker and intracorporeal delivery thereof |
US6725083B1 (en) | 1999-02-02 | 2004-04-20 | Senorx, Inc. | Tissue site markers for in VIVO imaging |
US7651505B2 (en) | 2002-06-17 | 2010-01-26 | Senorx, Inc. | Plugged tip delivery for marker placement |
US6862470B2 (en) | 1999-02-02 | 2005-03-01 | Senorx, Inc. | Cavity-filling biopsy site markers |
US8498693B2 (en) | 1999-02-02 | 2013-07-30 | Senorx, Inc. | Intracorporeal marker and marker delivery device |
US8361082B2 (en) | 1999-02-02 | 2013-01-29 | Senorx, Inc. | Marker delivery device with releasable plug |
US20090216118A1 (en) | 2007-07-26 | 2009-08-27 | Senorx, Inc. | Polysaccharide markers |
US9820824B2 (en) | 1999-02-02 | 2017-11-21 | Senorx, Inc. | Deployment of polysaccharide markers for treating a site within a patent |
EP1159015A1 (en) | 1999-03-04 | 2001-12-05 | Tepha, Inc. | Bioabsorbable, biocompatible polymers for tissue engineering |
US6548569B1 (en) | 1999-03-25 | 2003-04-15 | Metabolix, Inc. | Medical devices and applications of polyhydroxyalkanoate polymers |
US6575991B1 (en) | 1999-06-17 | 2003-06-10 | Inrad, Inc. | Apparatus for the percutaneous marking of a lesion |
EP1202670A4 (en) * | 1999-08-13 | 2004-11-10 | Point Biomedical Corp | Hollow microspheres with controlled fragility for medical use |
AU6635900A (en) * | 1999-08-13 | 2001-03-13 | Point Biomedical Corporation | Microparticles useful as ultrasonic contrast agents and for lymphatic system |
US7678364B2 (en) | 1999-08-25 | 2010-03-16 | Alkermes, Inc. | Particles for inhalation having sustained release properties |
US6749835B1 (en) | 1999-08-25 | 2004-06-15 | Advanced Inhalation Research, Inc. | Formulation for spray-drying large porous particles |
US6368275B1 (en) | 1999-10-07 | 2002-04-09 | Acuson Corporation | Method and apparatus for diagnostic medical information gathering, hyperthermia treatment, or directed gene therapy |
US20030144570A1 (en) * | 1999-11-12 | 2003-07-31 | Angiotech Pharmaceuticals, Inc. | Compositions and methods for treating disease utilizing a combination of radioactive therapy and cell-cycle inhibitors |
DE10013850A1 (en) * | 2000-03-15 | 2001-09-20 | Schering Ag | Gas-filled microcapsules, useful for ultrasonic diagnosis, are prepared from functionalized poly(alkyl cyanoacrylate), allowing attachment of e.g. specific-binding agents |
EP1780283A1 (en) | 2000-04-21 | 2007-05-02 | Martek Biosciences Corporation | Trophic conversion of obligate photographic algae through metabolic engineering |
EP2279757A3 (en) | 2000-06-02 | 2011-08-03 | Bracco Suisse SA | Compounds for targeting endothelial cells |
DE10027393B4 (en) * | 2000-06-02 | 2007-05-16 | Wella Ag | Poly- and oligoesters of cationic hydroxy acids, process for their preparation and their use |
CA2775170C (en) | 2000-11-20 | 2017-09-05 | Senorx, Inc. | An intracorporeal marker delivery system for marking a tissue site |
EP1345629A2 (en) | 2000-12-29 | 2003-09-24 | Advanced Inhalation Research, Inc. | Particles for inhalation having sustained release properties |
WO2002078611A2 (en) * | 2001-03-30 | 2002-10-10 | Drexel University | Echogenic polymer microcapsules and nanocapsules and methods for production and use thereof |
US7897141B2 (en) * | 2002-04-01 | 2011-03-01 | Drexel University | Echogenic polymer microcapsules and nanocapsules and methods for production and use thereof |
AU2002253454A1 (en) * | 2001-04-06 | 2002-10-21 | Bracco Research S.A. | Method for improved measurement of local physical parameters in afluid-filled cavity |
DE10119522A1 (en) * | 2001-04-20 | 2002-12-05 | Innovacell Biotechnologie Gmbh | Preparation and application of a suspension composition with an ultrasound contrast medium |
EP1587944A4 (en) | 2002-03-01 | 2007-03-21 | Dyax Corp | Kdr and vegf/kdr binding peptides and their use in diagnosis and therapy |
JP2006514915A (en) | 2002-03-01 | 2006-05-18 | ダイアックス、コープ | KDR and VEGF / KDR binding peptides and their use in diagnosis and therapy |
US7261876B2 (en) | 2002-03-01 | 2007-08-28 | Bracco International Bv | Multivalent constructs for therapeutic and diagnostic applications |
US7794693B2 (en) * | 2002-03-01 | 2010-09-14 | Bracco International B.V. | Targeting vector-phospholipid conjugates |
US7211240B2 (en) | 2002-03-01 | 2007-05-01 | Bracco International B.V. | Multivalent constructs for therapeutic and diagnostic applications |
US8623822B2 (en) | 2002-03-01 | 2014-01-07 | Bracco Suisse Sa | KDR and VEGF/KDR binding peptides and their use in diagnosis and therapy |
US6890592B2 (en) | 2002-03-13 | 2005-05-10 | Appleton Papers Inc. | Uniform microcapsules |
US7462366B2 (en) | 2002-03-29 | 2008-12-09 | Boston Scientific Scimed, Inc. | Drug delivery particle |
US6919068B2 (en) * | 2002-05-17 | 2005-07-19 | Point Biomedical Corporation | Method of preparing gas-filled polymer matrix microparticles useful for echographic imaging |
US20030215394A1 (en) * | 2002-05-17 | 2003-11-20 | Short Robert E. | Microparticles having a matrix interior useful for ultrasound triggered delivery of drugs into the bloodstream |
US7842377B2 (en) | 2003-08-08 | 2010-11-30 | Boston Scientific Scimed, Inc. | Porous polymeric particle comprising polyvinyl alcohol and having interior to surface porosity-gradient |
US8012454B2 (en) | 2002-08-30 | 2011-09-06 | Boston Scientific Scimed, Inc. | Embolization |
US7883490B2 (en) | 2002-10-23 | 2011-02-08 | Boston Scientific Scimed, Inc. | Mixing and delivery of therapeutic compositions |
US20060036158A1 (en) | 2003-11-17 | 2006-02-16 | Inrad, Inc. | Self-contained, self-piercing, side-expelling marking apparatus |
KR101076053B1 (en) * | 2003-02-04 | 2011-10-21 | 브라코 인터내셔날 비.브이. | Ultrasound contrast agents and process for the preparation thereof |
US20070128117A1 (en) * | 2003-02-04 | 2007-06-07 | Bracco International B.V. | Ultrasound contrast agents and process for the preparation thereof |
EP1592456A1 (en) | 2003-02-13 | 2005-11-09 | BRACCO IMAGING S.p.A. | Contrast enhanced x-ray phase imaging |
SI2949658T1 (en) | 2003-03-03 | 2018-10-30 | Dyax Corp. | Peptides that specifically bind HGF receptor (cMet) and uses thereof |
US20040185108A1 (en) * | 2003-03-18 | 2004-09-23 | Short Robert E. | Method of preparing gas-filled polymer matrix microparticles useful for delivering drug |
ITFI20030077A1 (en) * | 2003-03-26 | 2004-09-27 | Actis Active Sensors S R L | METHOD FOR THE ECOGRAPHICAL SURVEY THROUGH CONTRAST MEANS |
ES2819189T3 (en) | 2003-05-08 | 2021-04-15 | Tepha Inc | Polyhydroxyalkanoate Medical Fibers and Fabrics |
US7877133B2 (en) | 2003-05-23 | 2011-01-25 | Senorx, Inc. | Marker or filler forming fluid |
US8021303B2 (en) | 2003-06-12 | 2011-09-20 | Bracco Research Sa | System for extracting morphological information through a perfusion assessment process |
JP4706003B2 (en) | 2003-06-12 | 2011-06-22 | ブラッコ・シュイス・ソシエテ・アノニム | Blood flow evaluation method using supplemental curve fitting in ultrasound contrast images |
JP2007522085A (en) * | 2003-06-27 | 2007-08-09 | スミスクライン・ビーチャム・コーポレイション | Stabilized topotecan liposome compositions and methods |
JP2007528853A (en) * | 2003-07-08 | 2007-10-18 | テファ, インコーポレイテッド | Poly-4-hydroxybutyrate matrix for sustained release drug delivery |
CA2536510C (en) * | 2003-08-22 | 2011-01-18 | Tepha, Inc. | Polyhydroxyalkanoate nerve regeneration devices |
US7976823B2 (en) | 2003-08-29 | 2011-07-12 | Boston Scientific Scimed, Inc. | Ferromagnetic particles and methods |
SE0302794D0 (en) * | 2003-10-24 | 2003-10-24 | Per Hansson | Novel microparticles for ultrasound contrast imaging and drug delivery |
EP1677738A2 (en) | 2003-10-31 | 2006-07-12 | Point Biomedical Corporation | Reconstitutable microsphere compositions useful as ultrasonic contrast agents |
US7901770B2 (en) | 2003-11-04 | 2011-03-08 | Boston Scientific Scimed, Inc. | Embolic compositions |
US20050273002A1 (en) | 2004-06-04 | 2005-12-08 | Goosen Ryan L | Multi-mode imaging marker |
EP1701745B1 (en) * | 2003-12-22 | 2014-12-10 | Bracco Suisse S.A. | Gas-filled microvesicle assembly for contrast imaging |
JP2007515471A (en) * | 2003-12-22 | 2007-06-14 | ブラッコ・リサーチ・ソシエテ・アノニム | Assembly of gas-filled microvesicles with active ingredients for contrast imaging |
US8708909B2 (en) | 2004-01-20 | 2014-04-29 | Fujifilm Visualsonics, Inc. | High frequency ultrasound imaging using contrast agents |
US7025726B2 (en) | 2004-01-22 | 2006-04-11 | The Regents Of The University Of Nebraska | Detection of endothelial dysfunction by ultrasonic imaging |
US7736671B2 (en) | 2004-03-02 | 2010-06-15 | Boston Scientific Scimed, Inc. | Embolization |
US8173176B2 (en) | 2004-03-30 | 2012-05-08 | Boston Scientific Scimed, Inc. | Embolization |
US7311861B2 (en) | 2004-06-01 | 2007-12-25 | Boston Scientific Scimed, Inc. | Embolization |
US8012457B2 (en) | 2004-06-04 | 2011-09-06 | Acusphere, Inc. | Ultrasound contrast agent dosage formulation |
PL1778305T3 (en) * | 2004-08-03 | 2011-04-29 | Tepha Inc | Non-curling polyhydroxyalkanoate sutures |
GB2445322B (en) | 2004-08-13 | 2008-08-06 | Stichting Tech Wetenschapp | Intravasular ultrasound techniques |
CA2575677C (en) | 2004-08-18 | 2013-01-22 | Bracco Research Sa | Gas-filled microvesicles composition for contrast imaging |
US8425550B2 (en) | 2004-12-01 | 2013-04-23 | Boston Scientific Scimed, Inc. | Embolic coils |
CN100556368C (en) | 2004-12-23 | 2009-11-04 | 伯拉考开发股份有限公司 | Perfusion assessment method and system based on bolus injection |
EP1853333A1 (en) * | 2004-12-23 | 2007-11-14 | Bracco Research S.A. | Liquid transfer device for medical dispensing containers |
JP2008528204A (en) * | 2005-01-28 | 2008-07-31 | テファ, インコーポレイテッド | Embolization using poly-4-hydroxybutyrate particles |
US7858183B2 (en) | 2005-03-02 | 2010-12-28 | Boston Scientific Scimed, Inc. | Particles |
US7727555B2 (en) | 2005-03-02 | 2010-06-01 | Boston Scientific Scimed, Inc. | Particles |
WO2006094951A1 (en) | 2005-03-03 | 2006-09-14 | Bracco Research Sa | Medical imaging system based on a targeted contrast agent |
EP1714642A1 (en) * | 2005-04-18 | 2006-10-25 | Bracco Research S.A. | Pharmaceutical composition comprising gas-filled microcapsules for ultrasound mediated delivery |
US10357328B2 (en) | 2005-04-20 | 2019-07-23 | Bard Peripheral Vascular, Inc. and Bard Shannon Limited | Marking device with retractable cannula |
US7963287B2 (en) | 2005-04-28 | 2011-06-21 | Boston Scientific Scimed, Inc. | Tissue-treatment methods |
US9463426B2 (en) | 2005-06-24 | 2016-10-11 | Boston Scientific Scimed, Inc. | Methods and systems for coating particles |
US8052658B2 (en) | 2005-10-07 | 2011-11-08 | Bard Peripheral Vascular, Inc. | Drug-eluting tissue marker |
US8007509B2 (en) | 2005-10-12 | 2011-08-30 | Boston Scientific Scimed, Inc. | Coil assemblies, components and methods |
US9198639B2 (en) | 2005-11-10 | 2015-12-01 | Bracco Suisse S.A. | Detection of immobilized contrast agent in medical imaging applications based on flow dynamics analysis |
WO2007058969A2 (en) * | 2005-11-10 | 2007-05-24 | Wolverine Tube, Inc. | Brazing material with continuous length layer of elastomer containing a flux |
US8634608B2 (en) | 2005-11-10 | 2014-01-21 | Bracco Suisse S.A. | Instantaneous visualization of contrast agent concentration in imaging applications |
EP1797919A1 (en) * | 2005-12-16 | 2007-06-20 | Bracco Research S.A. | Liquid transfer device for medical dispensing containers |
US8101197B2 (en) | 2005-12-19 | 2012-01-24 | Stryker Corporation | Forming coils |
US8152839B2 (en) | 2005-12-19 | 2012-04-10 | Boston Scientific Scimed, Inc. | Embolic coils |
US7947368B2 (en) | 2005-12-21 | 2011-05-24 | Boston Scientific Scimed, Inc. | Block copolymer particles |
JP2007196223A (en) * | 2005-12-28 | 2007-08-09 | National Institute Of Advanced Industrial & Technology | Manufacturing method of hollow microcapsule |
US7967753B2 (en) * | 2006-08-01 | 2011-06-28 | Stichting Voor de Technische Wetenschappen of Van Vollenhovenlaan | Pulse inversion sequences for nonlinear imaging |
EP2079385B1 (en) | 2006-10-23 | 2013-11-20 | C.R.Bard, Inc. | Breast marker |
US8414927B2 (en) | 2006-11-03 | 2013-04-09 | Boston Scientific Scimed, Inc. | Cross-linked polymer particles |
US7943683B2 (en) * | 2006-12-01 | 2011-05-17 | Tepha, Inc. | Medical devices containing oriented films of poly-4-hydroxybutyrate and copolymers |
WO2008073965A2 (en) | 2006-12-12 | 2008-06-19 | C.R. Bard Inc. | Multiple imaging mode tissue marker |
ES2432572T3 (en) | 2006-12-18 | 2013-12-04 | C.R. Bard, Inc. | Biopsy marker with imaging properties generated in situ |
WO2008075192A2 (en) * | 2006-12-19 | 2008-06-26 | Bracco International Bv | Targeting and therapeutic compounds and gas-filled microvesicles comprising said com ounds |
US8512249B2 (en) | 2006-12-21 | 2013-08-20 | Bracco International Bv | Detection of the detachment of immobilized contrast agent in medical imaging applications |
JP4967101B2 (en) * | 2006-12-28 | 2012-07-04 | 独立行政法人産業技術総合研究所 | Method for producing hollow microcapsules |
EP2476703A1 (en) | 2011-01-14 | 2012-07-18 | Bracco Imaging S.p.A | Human antibodies cross-reacting with a bacterial and a self antigen from atherosclerotic plaques |
EP2200652B1 (en) * | 2007-09-27 | 2018-03-21 | Children's Medical Center Corporation | Microbubbles and methods for oxygen delivery |
US10130342B2 (en) | 2007-12-28 | 2018-11-20 | Bracco Suisse Sa | Initialization of fitting parameters for perfusion assessment based on bolus administration |
WO2009083557A1 (en) | 2007-12-28 | 2009-07-09 | Bracco Research S.A. | Quantification analisys of immobilized contrast agent in medical imaging applications |
US8311610B2 (en) | 2008-01-31 | 2012-11-13 | C. R. Bard, Inc. | Biopsy tissue marker |
EP2090322A1 (en) | 2008-02-18 | 2009-08-19 | INSERM (Institut National de la Santé et de la Recherche Médicale) | Use of fsh receptor ligands for diagnosis and therapy of cancer |
EP2103313A1 (en) * | 2008-03-19 | 2009-09-23 | Koninklijke Philips Electronics N.V. | Method for the synthesis of hollow spheres |
GB0811856D0 (en) | 2008-06-27 | 2008-07-30 | Ucl Business Plc | Magnetic microbubbles, methods of preparing them and their uses |
EP2147684A1 (en) | 2008-07-22 | 2010-01-27 | Bracco Imaging S.p.A | Diagnostic Agents Selective Against Metalloproteases |
US9327061B2 (en) | 2008-09-23 | 2016-05-03 | Senorx, Inc. | Porous bioabsorbable implant |
US9192685B2 (en) * | 2008-10-07 | 2015-11-24 | Bracco Suisse S.A. | Targeting construct comprising anti-polymer antibody and contrast/therapeutic agents binding to the same |
EP2189112A1 (en) | 2008-11-24 | 2010-05-26 | Bracco Research S.A. | Real-time perfusion imaging and quantification |
JP5341205B2 (en) | 2008-12-16 | 2013-11-13 | ブラッコ・シュイス・ソシエテ・アノニム | Contrast agent bolus administration device |
ES2560515T3 (en) | 2008-12-30 | 2016-02-19 | C.R. Bard, Inc. | Marker administration device for tissue marker placement |
CN102460506B (en) | 2009-06-08 | 2017-07-21 | 博莱科瑞士股份有限公司 | The auto-scaling of parametric image |
US8929634B2 (en) | 2009-09-01 | 2015-01-06 | Bracco Suisse Sa | Parametric images based on dynamic behavior over time |
US8420259B2 (en) * | 2009-10-14 | 2013-04-16 | GM Global Technology Operations LLC | Electrodes including an embedded compressible or shape changing component |
ES2764971T3 (en) * | 2009-12-22 | 2020-06-05 | Evonik Corp | Emulsion-based process for preparing microparticles and working head assembly for use with it |
EP2345732A1 (en) | 2010-01-19 | 2011-07-20 | Universite Paris Descartes | Methods for intracellular delivery of nucleic acids |
EP2544593B1 (en) | 2010-03-09 | 2014-12-31 | Bracco Suisse SA | Initialization of fitting parameters for perfusion assessment based on bolus administration |
US20110269657A1 (en) * | 2010-04-28 | 2011-11-03 | Jiten Odhavji Dihora | Delivery particles |
EP2603242B1 (en) | 2010-08-09 | 2018-03-14 | Bracco Suisse SA | Targeted gas-filled microvesicles |
BR112013002945A2 (en) | 2010-08-09 | 2016-06-07 | Inst Nat Sante Rech Med | a pharmaceutical composition formulated with a microbubble echo-contrast agent and a therapeutic nucleic acid of interest for use in a method for treating an eye disease in a subject. |
EP2654788B1 (en) | 2010-12-24 | 2018-03-14 | Bracco Suisse SA | Gas-filled microvesicles for use as vaccine |
EP2474327A1 (en) | 2011-01-07 | 2012-07-11 | RWTH Aachen | Microdosing of ultrasound contrast agents |
WO2012095516A1 (en) | 2011-01-14 | 2012-07-19 | Bracco Imaging Spa | Human antibodies cross-reacting with a bacterial and a self antigen from atherosclerotic plaques |
DE102011005444A1 (en) * | 2011-03-11 | 2012-09-13 | Innora Gmbh | Solid, negative X-ray contrast agent for imaging of the gastrointestinal tract |
WO2012136813A2 (en) | 2011-04-07 | 2012-10-11 | Universitetet I Oslo | Agents for medical radar diagnosis |
EP2545908A1 (en) | 2011-07-11 | 2013-01-16 | RWTH Aachen | Medium for microbubbles or microparticles and preparation thereof |
WO2013013038A2 (en) * | 2011-07-19 | 2013-01-24 | Trustees Of Boston University | Doping agents and polymeric compositions thereof for controlled drug delivery |
US10357450B2 (en) | 2012-04-06 | 2019-07-23 | Children's Medical Center Corporation | Process for forming microbubbles with high oxygen content and uses thereof |
RU2508094C1 (en) * | 2012-08-03 | 2014-02-27 | Андрей Юрьевич Хоменко | Methods for preparing transdermal therapeutic systems based on poly(lactic-co-glycolic acid) (versions) |
EP2936433B1 (en) | 2012-12-21 | 2018-09-19 | Bracco Suisse SA | Segmentation in diagnostic imaging applications based on statistical analysis over time |
US20160030603A1 (en) | 2013-03-15 | 2016-02-04 | Westfaelische Wilhelms-Universitaet Muenster | Detection of acute renal allograft rejection |
WO2014144364A1 (en) | 2013-03-15 | 2014-09-18 | Children's Medical Center Corporation | Gas-filled stabilized particles and methods of use |
EP3016713B1 (en) | 2013-07-03 | 2023-03-01 | Bracco Suisse SA | Devices for the ultrasound treatment of ischemic stroke |
USD716451S1 (en) | 2013-09-24 | 2014-10-28 | C. R. Bard, Inc. | Tissue marker for intracorporeal site identification |
USD716450S1 (en) | 2013-09-24 | 2014-10-28 | C. R. Bard, Inc. | Tissue marker for intracorporeal site identification |
USD715942S1 (en) | 2013-09-24 | 2014-10-21 | C. R. Bard, Inc. | Tissue marker for intracorporeal site identification |
USD715442S1 (en) | 2013-09-24 | 2014-10-14 | C. R. Bard, Inc. | Tissue marker for intracorporeal site identification |
US10368842B2 (en) | 2014-04-07 | 2019-08-06 | Bracco Suisse S.A. | Estimation of acoustic level in-situ with non-fundamental analysis |
US10449156B2 (en) | 2014-07-23 | 2019-10-22 | Universidad Andrés Bello | Controlled release system including a gas or volatile encapsulated in a polymeric support and a matrix system, a method of preparing the system, and their use |
WO2016025329A1 (en) | 2014-08-15 | 2016-02-18 | Tepha, Inc. | Self-retaining sutures of poly-4-hydroxybutyrate and copolymers thereof |
US10626521B2 (en) | 2014-12-11 | 2020-04-21 | Tepha, Inc. | Methods of manufacturing mesh sutures from poly-4-hydroxybutyrate and copolymers thereof |
US9555155B2 (en) | 2014-12-11 | 2017-01-31 | Tepha, Inc. | Methods of orienting multifilament yarn and monofilaments of poly-4-hydroxybutyrate and copolymers thereof |
MX2017008721A (en) | 2014-12-31 | 2017-11-17 | Lantheus Medical Imaging Inc | Lipid-encapsulated gas microsphere compositions and related methods. |
JP2018538056A (en) | 2015-12-09 | 2018-12-27 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | Interleaved beam pattern for ultrasonic thrombolysis and other treatments via vascular acoustic resonator |
CN108289654B (en) | 2015-12-10 | 2021-03-30 | 博莱科瑞士股份有限公司 | Detection of immobilized contrast agents by dynamic thresholding |
AU2017218024B2 (en) | 2016-02-09 | 2020-12-17 | Bracco Suisse Sa | A recombinant chimeric protein for selectins targeting |
KR20180133527A (en) | 2016-05-04 | 2018-12-14 | 랜티우스 메디컬 이메징, 인크. | Method and apparatus for producing ultrasound contrast agent |
US9789210B1 (en) | 2016-07-06 | 2017-10-17 | Lantheus Medical Imaging, Inc. | Methods for making ultrasound contrast agents |
US11147890B2 (en) | 2017-02-28 | 2021-10-19 | Children's Medical Center Corporation | Stimuli-responsive particles encapsulating a gas and methods of use |
WO2019006029A1 (en) | 2017-06-27 | 2019-01-03 | Lawrence Livermore National Security, Llc | Elastomeric shape memory polymer composites |
CN115400230B (en) * | 2022-09-03 | 2023-12-22 | 福建医科大学附属协和医院 | Novel multifunctional gastrointestinal ultrasound contrast agent |
Family Cites Families (80)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3968203A (en) * | 1965-10-01 | 1976-07-06 | Jerome G. Spitzer | Aerosol astringent composition |
US3615972A (en) * | 1967-04-28 | 1971-10-26 | Dow Chemical Co | Expansible thermoplastic polymer particles containing volatile fluid foaming agent and method of foaming the same |
US3650831A (en) * | 1969-03-10 | 1972-03-21 | Armour Dial Inc | Method of cleaning surfaces |
US3900420A (en) * | 1970-05-18 | 1975-08-19 | Felix Sebba | Microgas emulsions and method of forming same |
US4027007A (en) * | 1970-12-09 | 1977-05-31 | Colgate-Palmolive Company | Antiperspirants formulated with borax |
US4089800A (en) * | 1975-04-04 | 1978-05-16 | Ppg Industries, Inc. | Method of preparing microcapsules |
GB1575343A (en) * | 1977-05-10 | 1980-09-17 | Ici Ltd | Method for preparing liposome compositions containing biologically active compounds |
CH624011A5 (en) * | 1977-08-05 | 1981-07-15 | Battelle Memorial Institute | |
CH621479A5 (en) * | 1977-08-05 | 1981-02-13 | Battelle Memorial Institute | |
US4235871A (en) * | 1978-02-24 | 1980-11-25 | Papahadjopoulos Demetrios P | Method of encapsulating biologically active materials in lipid vesicles |
US4192859A (en) * | 1978-09-29 | 1980-03-11 | E. R. Squibb & Sons, Inc. | Contrast media containing liposomes as carriers |
IL58965A (en) * | 1978-12-19 | 1982-08-31 | Mars Inc | Production of microcapsules |
US4276885A (en) * | 1979-05-04 | 1981-07-07 | Rasor Associates, Inc | Ultrasonic image enhancement |
US4265251A (en) * | 1979-06-28 | 1981-05-05 | Rasor Associates, Inc. | Method of determining pressure within liquid containing vessel |
US4316391A (en) * | 1979-11-13 | 1982-02-23 | Ultra Med, Inc. | Flow rate measurement |
US4681119A (en) * | 1980-11-17 | 1987-07-21 | Schering Aktiengesellschaft | Method of production and use of microbubble precursors |
US4442843A (en) * | 1980-11-17 | 1984-04-17 | Schering, Ag | Microbubble precursors and methods for their production and use |
US4657756A (en) * | 1980-11-17 | 1987-04-14 | Schering Aktiengesellschaft | Microbubble precursors and apparatus for their production and use |
US4675189A (en) * | 1980-11-18 | 1987-06-23 | Syntex (U.S.A.) Inc. | Microencapsulation of water soluble active polypeptides |
FR2504408B1 (en) * | 1981-04-24 | 1986-02-14 | Couvreur Patrick | PROCESS FOR THE PREPARATION OF SUBMICROSCOPIC PARTICLES, PARTICLES THUS OBTAINED AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM |
DE3141641A1 (en) * | 1981-10-16 | 1983-04-28 | Schering Ag, 1000 Berlin Und 4619 Bergkamen | ULTRASONIC CONTRAST AGENTS AND THEIR PRODUCTION |
US4511515A (en) * | 1983-06-28 | 1985-04-16 | Corning Glass Works | Method for making a volatile cerium diketonate compound |
US4572203A (en) * | 1983-01-27 | 1986-02-25 | Feinstein Steven B | Contact agents for ultrasonic imaging |
US4718433A (en) * | 1983-01-27 | 1988-01-12 | Feinstein Steven B | Contrast agents for ultrasonic imaging |
DE3313946A1 (en) * | 1983-04-15 | 1984-10-18 | Schering AG, 1000 Berlin und 4709 Bergkamen | MICROPARTICLES AND GAS BUBBLES CONTAINING ULTRASONIC CONTRASTING AGENTS |
DE3313947A1 (en) * | 1983-04-15 | 1984-10-18 | Schering AG, 1000 Berlin und 4709 Bergkamen | MICROPARTICLES AND GAS BUBBLES CONTAINING ULTRASONIC CONTRASTING AGENTS |
US5141738A (en) * | 1983-04-15 | 1992-08-25 | Schering Aktiengesellschaft | Ultrasonic contrast medium comprising gas bubbles and solid lipophilic surfactant-containing microparticles and use thereof |
US4900540A (en) * | 1983-06-20 | 1990-02-13 | Trustees Of The University Of Massachusetts | Lipisomes containing gas for ultrasound detection |
DE3324235A1 (en) * | 1983-07-01 | 1985-01-10 | Schering AG, 1000 Berlin und 4709 Bergkamen | NEW COMPLEX ILLUMINATORS, COMPLEX AND COMPLEX SALTS |
US5618514A (en) * | 1983-12-21 | 1997-04-08 | Nycomed Imaging As | Diagnostic and contrast agent |
CA1215922A (en) * | 1984-05-25 | 1986-12-30 | Connaught Laboratories Limited | Microencapsulation of living tissue and cells |
GB8504916D0 (en) * | 1985-02-26 | 1985-03-27 | Isc Chemicals Ltd | Emulsions of perfluorocarbons in aqueous media |
DE3529195A1 (en) * | 1985-08-14 | 1987-02-26 | Max Planck Gesellschaft | CONTRAST AGENTS FOR ULTRASONIC EXAMINATIONS AND METHOD FOR THE PRODUCTION THEREOF |
CH667874A5 (en) * | 1985-12-19 | 1988-11-15 | Battelle Memorial Institute | BIODEGRADABLE SYNTHETIC POLYPEPTIDE AND ITS USE FOR THE PREPARATION OF MEDICAMENTS. |
US4927623A (en) * | 1986-01-14 | 1990-05-22 | Alliance Pharmaceutical Corp. | Dissolution of gas in a fluorocarbon liquid |
DE3637926C1 (en) * | 1986-11-05 | 1987-11-26 | Schering Ag | Ultrasonic manometry in a liquid using microbubbles |
FR2608942B1 (en) * | 1986-12-31 | 1991-01-11 | Centre Nat Rech Scient | PROCESS FOR THE PREPARATION OF COLLOIDAL DISPERSIBLE SYSTEMS OF A SUBSTANCE, IN THE FORM OF NANOCAPSULES |
US5283067A (en) * | 1987-01-30 | 1994-02-01 | Ciba-Geigy Corporation | Parenteral suspensions |
US5089181A (en) * | 1987-02-24 | 1992-02-18 | Vestar, Inc. | Method of dehydrating vesicle preparations for long term storage |
CH672733A5 (en) * | 1987-05-22 | 1989-12-29 | Bracco Ind Chimica Spa | |
DE3721721C1 (en) * | 1987-07-01 | 1988-06-09 | Hoechst Ag | Process for coating granules |
DE3741201A1 (en) * | 1987-12-02 | 1989-06-15 | Schering Ag | ULTRASONIC PROCESS AND METHOD FOR IMPLEMENTING IT |
IE61591B1 (en) * | 1987-12-29 | 1994-11-16 | Molecular Biosystems Inc | Concentrated stabilized microbubble-type ultrasonic imaging agent and method of production |
US4844882A (en) * | 1987-12-29 | 1989-07-04 | Molecular Biosystems, Inc. | Concentrated stabilized microbubble-type ultrasonic imaging agent |
US5425366A (en) * | 1988-02-05 | 1995-06-20 | Schering Aktiengesellschaft | Ultrasonic contrast agents for color Doppler imaging |
US5730954A (en) * | 1988-08-23 | 1998-03-24 | Schering Aktiengesellschaft | Preparation comprising cavitate- or clathrate-forming host/guest complexes as contrast agent |
US4957656A (en) * | 1988-09-14 | 1990-09-18 | Molecular Biosystems, Inc. | Continuous sonication method for preparing protein encapsulated microbubbles |
DE3934656A1 (en) * | 1989-10-13 | 1991-04-18 | Schering Ag | METHOD FOR PRODUCING AQUEOUS DISPERSIONS |
US5088499A (en) * | 1989-12-22 | 1992-02-18 | Unger Evan C | Liposomes as contrast agents for ultrasonic imaging and methods for preparing the same |
US5228446A (en) * | 1989-12-22 | 1993-07-20 | Unger Evan C | Gas filled liposomes and their use as ultrasonic contrast agents |
US5776429A (en) * | 1989-12-22 | 1998-07-07 | Imarx Pharmaceutical Corp. | Method of preparing gas-filled microspheres using a lyophilized lipids |
US5123414A (en) * | 1989-12-22 | 1992-06-23 | Unger Evan C | Liposomes as contrast agents for ultrasonic imaging and methods for preparing the same |
US5209720A (en) * | 1989-12-22 | 1993-05-11 | Unger Evan C | Methods for providing localized therapeutic heat to biological tissues and fluids using gas filled liposomes |
DE4004430A1 (en) * | 1990-02-09 | 1991-08-14 | Schering Ag | CONSTRUCTED POLYALDEHYDE CONSTITUENTS |
US5556610A (en) * | 1992-01-24 | 1996-09-17 | Bracco Research S.A. | Gas mixtures useful as ultrasound contrast media, contrast agents containing the media and method |
US5445813A (en) * | 1992-11-02 | 1995-08-29 | Bracco International B.V. | Stable microbubble suspensions as enhancement agents for ultrasound echography |
US5578292A (en) * | 1991-11-20 | 1996-11-26 | Bracco International B.V. | Long-lasting aqueous dispersions or suspensions of pressure-resistant gas-filled microvesicles and methods for the preparation thereof |
IN172208B (en) * | 1990-04-02 | 1993-05-01 | Sint Sa | |
US5205287A (en) * | 1990-04-26 | 1993-04-27 | Hoechst Aktiengesellschaft | Ultrasonic contrast agents, processes for their preparation and the use thereof as diagnostic and therapeutic agents |
US5137928A (en) * | 1990-04-26 | 1992-08-11 | Hoechst Aktiengesellschaft | Ultrasonic contrast agents, processes for their preparation and the use thereof as diagnostic and therapeutic agents |
US5190982A (en) * | 1990-04-26 | 1993-03-02 | Hoechst Aktiengesellschaft | Ultrasonic contrast agents, processes for their preparation and the use thereof as diagnostic and therapeutic agents |
AU636481B2 (en) * | 1990-05-18 | 1993-04-29 | Bracco International B.V. | Polymeric gas or air filled microballoons usable as suspensions in liquid carriers for ultrasonic echography |
US5487390A (en) * | 1990-10-05 | 1996-01-30 | Massachusetts Institute Of Technology | Gas-filled polymeric microbubbles for ultrasound imaging |
US5149329A (en) * | 1990-12-12 | 1992-09-22 | Wayne State University | Surgical suture carrier and method for urinary bladder neck suspension |
DE4100470A1 (en) * | 1991-01-09 | 1992-07-16 | Byk Gulden Lomberg Chem Fab | Echo contrast agent |
GB9106673D0 (en) * | 1991-03-28 | 1991-05-15 | Hafslund Nycomed As | Improvements in or relating to contrast agents |
GB9106686D0 (en) * | 1991-03-28 | 1991-05-15 | Hafslund Nycomed As | Improvements in or relating to contrast agents |
US5874062A (en) * | 1991-04-05 | 1999-02-23 | Imarx Pharmaceutical Corp. | Methods of computed tomography using perfluorocarbon gaseous filled microspheres as contrast agents |
US5205290A (en) * | 1991-04-05 | 1993-04-27 | Unger Evan C | Low density microspheres and their use as contrast agents for computed tomography |
US5147631A (en) * | 1991-04-30 | 1992-09-15 | Du Pont Merck Pharmaceutical Company | Porous inorganic ultrasound contrast agents |
US5364612A (en) * | 1991-05-06 | 1994-11-15 | Immunomedics, Inc. | Detection of cardiovascular lesions |
AU2317592A (en) * | 1991-07-05 | 1993-02-11 | University Of Rochester | Ultrasmall non-aggregated porous particles entrapping gas-bubbles |
US5409688A (en) * | 1991-09-17 | 1995-04-25 | Sonus Pharmaceuticals, Inc. | Gaseous ultrasound contrast media |
GB9200388D0 (en) * | 1992-01-09 | 1992-02-26 | Nycomed As | Improvements in or relating to contrast agents |
IL104084A (en) * | 1992-01-24 | 1996-09-12 | Bracco Int Bv | Long-lasting aqueous suspensions of pressure-resistant gas-filled microvesicles their preparation and contrast agents consisting of them |
EP0679066A4 (en) * | 1992-11-02 | 1996-04-03 | Univ Drexel | Surfactant-stabilized microbubble mixtures, process for preparing and methods of using the same. |
US5716597A (en) * | 1993-06-04 | 1998-02-10 | Molecular Biosystems, Inc. | Emulsions as contrast agents and method of use |
BR9406993A (en) * | 1993-07-02 | 1996-09-10 | Molecular Biosystems Inc | Microspheres of insoluble gases encapsulated with protein and their preparation and use as ultrasonic imaging agents |
DK0711179T3 (en) * | 1993-07-30 | 2005-02-14 | Imcor Pharmaceutical Co | Stabilized ultrasound microbubble compositions |
US5601085A (en) * | 1995-10-02 | 1997-02-11 | Nycomed Imaging As | Ultrasound imaging |
-
1991
- 1991-04-29 AU AU76144/91A patent/AU636481B2/en not_active Expired
- 1991-05-14 EP EP91810366A patent/EP0458745B2/en not_active Expired - Lifetime
- 1991-05-14 AT AT91810366T patent/ATE112173T1/en not_active IP Right Cessation
- 1991-05-14 DK DK91810366T patent/DK0458745T4/en active
- 1991-05-14 ES ES91810366T patent/ES2061217T5/en not_active Expired - Lifetime
- 1991-05-14 DE DE69104264T patent/DE69104264T3/en not_active Expired - Lifetime
- 1991-05-15 IL IL9814391A patent/IL98143A/en not_active IP Right Cessation
- 1991-05-15 IS IS3707A patent/IS1862B/en unknown
- 1991-05-15 KR KR1019910007865A patent/KR0142180B1/en not_active IP Right Cessation
- 1991-05-16 NZ NZ238160A patent/NZ238160A/en unknown
- 1991-05-16 HU HU9101646A patent/HU226007B1/en unknown
- 1991-05-16 CA CA002042722A patent/CA2042722C/en not_active Expired - Lifetime
- 1991-05-16 ZA ZA913729A patent/ZA913729B/en unknown
- 1991-05-16 HU HU911646A patent/HUT58508A/en unknown
- 1991-05-16 PL PL91290271A patent/PL166827B1/en not_active IP Right Cessation
- 1991-05-17 RU SU4895423A patent/RU2110991C1/en active
- 1991-05-17 CN CN91103411A patent/CN1055414C/en not_active Expired - Lifetime
- 1991-05-17 IE IE168791A patent/IE66895B1/en not_active IP Right Cessation
- 1991-05-17 JP JP3113100A patent/JP2897190B2/en not_active Expired - Fee Related
-
1994
- 1994-08-10 US US08/288,550 patent/US5711933A/en not_active Expired - Lifetime
- 1994-08-16 US US08/291,542 patent/US5840275A/en not_active Expired - Lifetime
-
1997
- 1997-03-04 US US08/810,447 patent/US5863520A/en not_active Expired - Lifetime
- 1997-08-13 US US08/910,149 patent/US6139818A/en not_active Expired - Fee Related
- 1997-08-13 US US08/910,152 patent/US6200548B1/en not_active Expired - Fee Related
- 1997-09-12 US US08/929,274 patent/US6123922A/en not_active Expired - Fee Related
-
2003
- 2003-12-03 US US10/725,777 patent/US20040126322A1/en not_active Abandoned
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