US2338102A - Ampoule - Google Patents

Description

Jan. 4, 1944. M. R. Fl ELDS 2,338,102

AMPULE Filed Sept, 3, 1940 INVENTOR MacK'RFiEZ 5 ATTQRN EY mate 1.... 4,1944

. attain maroon:v 'Mack Robert Fields, Chicago, 111. Application September s, 1940, sesam 355,135 11 Claims. (Cl. 128-272) This invention relates to ampoules such as are used with syringes for hypodermic or other iniections, particularly dental ampoules.

Ampoules of the type with which the present invention is concerned comprise a tube, generally of glass, which is closed at both ends by closure plugs; One of the closure plugs comprises a piston which may be forced into the tube to elect the liquid contents thereof through a hypodermic needle, which needle pierces either the piston closure or a pierceable plug at the opposite end of the tube.

In dealing with ampoules of the type wherein the hypodermic needle pierces a closure at an end of the tube opposite the piston plug, certain difflculties are frequently encountered due to a plugged hypodermic needle., As pressure is applied to the piston closure to force it into the tube the liquid within the tube is placed under the contents of the ampoule are confined against escape.

. It has heretofore been proposed to cover the outside of the pierceable closure plug with a thin layer of plastic material which extends over and onto the adjacent part of the glass tube. It has been found thatsuch a film as heretofore applied cannot hold the pierceable plug in place under appreciable pressure. It is one of the ob- Jects of the present invention to provide means for causing a sealing film to adhere to the glass of the tube with such tenacity and such form as to positively prevent expulsion of the pierceable piston plug and yet at the same time not interfere 'with the piercing thereof by a hypodermic needle. In accordance with one preferred embodiment of the present invention the end of the glass tube is etched to provide a roughened surface against which a sealing film will adhere tenaciously. The closure plug or disc is positioned in the ampoule tube with the end of the ampoule tube projecting beyond the end of the closure'for a very short distance, a distance of the order of a, of an inch or more. This provides a cavity within which a and the wall of the tube; In accordance with the 4 bit of thermo-plastic material may be placed and which will adhere to the closure disc and also adhere to the etched surface of the tube wall and form a thickened portion at, the interior surface of the tube wall to prevent shearing of thethermo-plastic layer by an outward force exerted thereagainst by the closure plug.

The preferred plastic film is one which has the property of adhering to glass with great tenacity, one which is easily pierceable by a hypodermic needle and will not dull the needle, one which is not frangible and will not break off when it is pierced by the needle and thus plug the needle opening during .piercing, and one which is sumciently flexible to prevent shearing of the plastic layer at the glass ampoule under pressure. I have found that an acrylic resin, known as 'Acryloid 3-72, is a suitable material. It is a toluol solution and in its commercial liquid form is 30% solid and 10% solvent. Toluol is a rubbersolvent and therefore as the liquid plastic is drying the toluol dissolves some of the rubber of the closure plug with which it is in contact sothat upon complete'drying of the plastic the plastic is integrally united with the rubber.

Heretofore it has been suggested to coat the end of an ampoule with plastic by dipping the ampoule into the liquid plastic in solution. I have found that the dipping process is not appli cable efficiently for coating the end of a tube wherein the closure disc is recessed within the tube. In a recessed structure dipping of the end downward into a viscous liquid plastic traps a bubble of air, preventing the'spread of the liquid plastic outwards from the center and upwards. It is essential that the liquid plastic spreads in an unbroken film without any trapping of minuteair bubbles along the juncture of the rubber plug principles of the present invention this difllculty is overcome by avoiding the dipping operation entirely. Instead the tube is held vertically with the end to be coated located uppermost, and one or several drops of liquid plastic is deposited in the recess formed by the inset disc in the end of the tube. As the plasticsolvent dries, the remaining solid material adheres to the surface of the glass tube and forms a layer which is appreciably thicker around the periphery of the disc than at the center. This acts as a positive stop to prevent forcing of the closure plug outwardly of the tube, since such forcing action would necessitate shearing of a thick mass of theme-plastic material.

ened rim of plastic material in proper position around; the inner periphery of the glass tube adjacent the outer surface of the closure plug the glass tube is squar ground at its end as distinuished from the usual flamed or rounded end of the glass tubes heretofore used. This facilitates formation of a thick layer of thermoplastic along the periphery of the closur plug andsassures holding. of the same against outward ejection.

It i a further object of the present invention to uses. closure plug of sheet rubber material as distinguished from the usual molded closure plugs. Rubber is inherently porous. When sheet material is used it is possible to treat the surfaces of the rubber to close the pores. This may be done before the sheet material is cut or stamped to form the individual closure plugs. Such treatme may comprise calendering, or coating a surface of the sheet with an inert material such as wax, a thermo-plastic, or the like. This provides a non-porous closure plug for the tube. In adaaaaroa I Inthe drawing:

Figure l is an enlarged longitudinal sectional view through a partially completed ampoule and illustrating one step in the process of complet- "ing the same;

Figure 2 is a longitudinal sectional view through a partially completed ampoule;

dition to the porosity of the molded plugs the rubber itself is not entirely chemically inert with the solutionin the tube. The use of sheet material makes possible an inexpensive method of treating chemically or applying an inert film to the sheet to render inert the surface of the subsequently cut disc-that is to be in contact with the chemicals in the tube.

l the tube I.

It is a still further object of the present inven tion to provide an improved method of filling and sealing an ampoule. In accordance with the preferred method rubber discs or diaphragms, which are ultimatelyto constitute sealing closures, are positioned in opposite ends of the ampoule at a substantial angle to the axis thereof so as not to prevent the flow of fluid into and through the ampoule tube. This may be done under nonsterile conditions. Thereafter, superheated steam is passed through the tube to sterilize the tube and the closure diaphragms, and then the ampoule may be filled with its sterile solution and th diaphragms righted. The diaphragms then provide temporary seals for maintaining the contents of the tube sterile while further operations for completing the ampoule are performed.

It is another object of the present invention to provide an improved piston closure plug for an The piston is preferably made of a ampoule. plurality of parts which includes a facing dia- .phragm that is capable of effecting a temporary sealin closure at the end of the ampoule. In the manufacture of the ampoule the diaphragm is positioned in the tube and at an angle to the Figure 3 is a lon itudinal sectional view through one end of the ampoule at a later stage in the process of manufacture;

Figure 4 is a longitudinal sectional view similar to Figure 3 and showing the ampoule in a still later stage in theprocess of making the same;

Figure 5 is a longitudinal sectional view through the same end of the completed ampoule; and

Figure 6 is a longitudinal sectional view through another type of ampoule embodying ,the present invention.

Reference may now be had more particularly to Figure 1 of the drawing- The ampoule of the present invention comprises a tube I of glass or other suitable material, which tube is circular in ,cross section and of uniform diameter throughout. The opposite ends 2--8 of the tube are ground to be perfectly flat and at right angles to the longitudinal axis of the tube, thus forming right angle corners between the surfaces 2 and 8 and the inner and outer peripheral walls of Because the tube is ground'perfect- 1y flat at the end surfaces 2 and 8 these surfaces can be located a fixed and predetermined distance a art, thus facilitating quantity assembly and filling of the ampoules.

Two end closure discs or diaphragms, indicated at 8 and 8, are then inserted into the tube. The

one surface 'of the sheet need be thus treated.

Each diaphragm is inserted into the tube 1 so that the treated end will ultimately be the end in contact with the solution within the tube. The diaphragms. 8 and 8 are circular in cross section and of adiameter slightly in excess of the internal diameter of the. tube. They. are inserted into the tube at an acut angle to the longitudinal axis of the tube, a illustrated in Figure 1, so that they do not close the ends of the tube but they are nevertheless held firmly axis thereof to permit the free passage of fiuid past the facing diaphragm. This i done before sterilization. After sterilization the diaphragm is righted to seal the end of the tube. The rest of the piston closure, of which the diaphragm is to constitute the face, may then be assembled.

The rest of the piston preferably comprises discs,

of rubber which form a seal with the tube wall, and discs of fiber or the like between the rubber discs, for assuring that the pressure is transmitted from onerubber disc to th next in an axial direction. This eliminates, or very greatly reduces, the tendency for'a long piston to bind or look with thesurface of theempoule tube when pressure is exerted thereagainst.

in position within the tube, since they are slightly oversized.

The interior of the tube may then be sterilized.

This may be accomplished by passing live superheated steam through the tube. The tube and the closure discs. 8 and 8 are thus completely sterilized. The tube I may then be placed in firm contact with a sterile sheet or plate I2 of yielding and moisture-proof material so that the end 8 5 forms a temporary seal with the plate I2. The

tion extending across the tube I.

The attainment of the above and further ob Jects of the present invention will be apparent from the following specification-taken in conjunction with the accompanying drawing forming a part thereof.

tube is then filled with the sterile medicine solution, being filled preferably to a height above the top of the disc 8 but certainly over the center of the disc 8. The disc 8 is then righted to a posi- This may be accomplished by a cylindrical plunger tool III of a diameter slightly less than the internal diameter of the tube I so that the tool can be inserted freely into the tube I.. The lower face of the plunger II 15 may be fiat across, or recessed as illustrated.

The tool or plunger II is mounted in a suitable mechanism adapted to rotate it'axially. The slowly rotating tool II is then lowered into the tube I. The tool first'engages the top II of the disc I and as the tool is further lowered, and

rotated, it rotates the disc I to a position such that its plane is at right angles to'the axis of the tube I, my pending application, Serial No. 340,329. This. as is pointed out above, is done after the tube has been filled with its solution. The or diaphragm I is then in a position within the tube such as illustrated in Figure I. The tool "II is then retracted from the tube I and the tube, with the contents thereof, and the closure sheet or plate II are reversed so that the disc or diaphragm I is now uppermost. The rotating tool II is then againlowered into the tube I to right the diaphragm I in the same manner that it righted the diaphragm I. Thereafter the diaphragm I may be pushed into the (tube I to push the diaphragm I is now necessary to convert these temporary seals into permanent seals. This may be accomplished under ordinary non-sterile conditions since the contents of the tube are maintained sterile and temporarily sealed from the atmosphere.. One end of the tube is built up to constitute the diaphragm I a facing surface of a slidable piston plunger II in the manner described in my pending application Serial No. 340,329, to which reference may ,be made for a further description. The other end is closed oil to form a permanent seal adapted toabe pierced by-a hypodermic needle. Either of the twoends may be sealed first.

Briefly, the piston plunger assembly, indicated at II, comprises the diaphragm I, two serrated rigid fiber" discs II, of a maximum outside diameter slightly less than the inside diameter of the tube I, and rubber closure plugs II making snug fits with the interior wall of the tube and having central holes II therein. The serrations II in the discs II, and the outer surfaces of the rubber closure plugs may be coated with glycerine which is medicated with a germicide and bactericide so that the glycerine acts as a lubricant to facilitate insertion of the closure plugs. As each closure plug II is assembled within the tube I the opening II therein constitutes an air passageway for the expulsion of air between the plug II and the ends adjacent theserrated disc II. Since the plugs 22 are never in contact with the medicine within the tube I they do not have to be made of a material which is resistant to the action of the medicine and which is chemically inert therewith. The plugs II may therefore bemade of a cheap grade of rubber.

An explanation will now be given of the manner of converting the temporary closure I into a bermanentseal. The tube is held with the end I lowermost and that end is then dipped into an etching solution to etch the end of the tube. The solution may comprise hydrofluoric acid which etches the glass but is inert with respect to the rubber I. The glass is etched along its outer periphery indicated in exaggerated form by the roughened part II and at its inner periphery as diately spreads out along the upper surface or the j diaphragm I to the wall of the tube I and rises along the periphery of the tube to the end I.

This may be due to a surface tension or capillary action' phenomenon. As the liquid contents of the thermo-plastic globule evaporate there is left a thin film I! which overlays and is adhered to the upper surface or the rubberdiaphrasm I and.

which also rises along the edge of the inner surface of the tube I to form a ridge or ring 28. This ridge or ring firmly adheresto the roughened or etched surface II of the tube and forms a liquidv tight, air-tight seal and also forms an abutment ring to prevent the expulsion of the dia hragm I by pressure within the ampoule I. A preferred thermo-plastic' material is an acrylic resin known as "Acryloid 13-72. It is a toluol solution and in its commercial liquid form is 30% solid and 70% solvent. Toluol is a rubber solvent and therefore as the liquid plastic is drying, the toluol dissolves some of the rubber of the closure diaphragm-with which it is in contact so that upon complete drying of the plastic the dried plastic is integrally united with the rubber. The pierceable closure end of the tube I is now in the condition illustrated in Figure 3. Thereafter another drop or globule of the same material as the globule II, but considerably thinned, as by the addition of toluol, so that it contains less solid and more solvent, is deposited upon the film I1. 20% solid and 80% solvent. It assumes the shape illustrated at II in Figure 4 overlying theend surface I of the tube. Thereafter as the solvent evaporates it forms a thin film 3| which overlies the end surface I of the tube I and is adhered thereto and extends over and is integrally united with the previously formed film or layer 21. There is thus formed a liquid-tight, air-tight seal over the end of the diaphragm I, which seal is firmly bonded to the glass l and includes the reglass tube, which ring is bonded to the etched surface of the glass to hold the ring firmly in place,

a and which ring acts as an abutment against expulsion of the diaphragm I. The thermo-plastic fllm is non-frangible and will not break oil when it is pierced by the hypodermic needle and thus will not plug the needle during piercing. It has sufilcient flexibility to prevent shearing-of the helping to hold the thermo-plastic film in place and avoiding the formation of a loose edge which might otherwise "cause peeling of the thermo plastic film. The etched surface It also provides a place for placing an identifying mark on the tube.

When the tube I is inserted into a hypodermio syringe the hypodermic needle is caused to pierce the diaphragm I. Thereafter a plunger of the syringe presses against the piston comprising the diaphragm I, the discs II-II and the plugs II-II to force the piston into the tube to This substance may be enforcing ring II along the inner periphery of the If any part of.

eject the liquid contents thereof through the hy; podermic needle. At that time the piston is placed under pressure by. the plunger of the syringe and the piston places the liquid contents of the cartridge I under pressure. The material 8 and 22- 22 being compressible, and being placed under axial pressure, will tend to expand radially and thus exert a greater pressure against the inner wall of the tube I. The spaces between the serrations 21 in the discs 2 I-2I as well as the spaces 23 in the plugs 22-22 constitute spaces for receiving some of the rubber of the diaphragm 9 and the plugs 22-22 which are being compressed. This reduces the pressure that would otherwise be applied to the wall of the tube i by the rubber of the diaphragm 8 and the plugs 22-22, thus reducing the tendency for the rubber to bind to the glass tube. By building up the piston of thin layers 9, 22-22 of rubber separated by nonrubber discs 2l-2l, the pressure is transmitted through the rubber plugs 22-22 in an axial direction throughout, thereby further reducing the tendency for the rubber to bind against the wall of the tube as the rubber is compressed by the 1 pressure which forcesthe piston inwardly. Furthermore, because the plugs 22-22 are comparatively thin, they may be fonned by stamping the same out of sheet rubber, which is appreciably cheaper than molded rubber.

In Figure 6 I have illustrated another standard type of ampoule to which the present invention is applicable. This ampoule is of the type illustrated, for instance, in United States Patent No. 1,715,771

and includes a glass tube circular in cross section.

having a pieroeable closure ll! at one end adapted to be pierced by a hypodermic needle and having a piston plug II at the opposite end adapted to tion is not limited to the precise constructions here shown. the same being merely illustrative of the principles of the invention. What I consider new and desire to secure by Letters Patents is: r

1. A liquid-tight container comprising a tube open at at least one end, the part of the tube ad- Jacent the open end being etched around the entire periphery thereof to provide a roughened surface. and a liquid-tight coherent film of plastic material extending across and sealing the opening and adhered to the roughened surface to hold the film against rupture by internal pressure.

2. A container comprising a. tube open at an end, the inner peripheral surface at the open end of the tube being etched to provide a roughened surface, a closure disc closing said one end of the tube with the outer surface of the closure disc located within the tube so that the end of the tube projects beyond the outer surface of the disc, and an air-tight film adhered to the outer surface of the disc and to the adjacent inner periphery of the tube ot said roughened surface.

3. A container comprising a tube open at both ends, a piston plug closing one end of the tube, a closure disc closing the opposite end of the tube with the outer surface of the closure disc located be forced into the tube to expel the liquid contents thereof through a hypodermic needle that pierces the closure 40. In a tube of this type there is considerable danger that the closure plug 40 will be forced out of the tube by the pressure within the tube in the event that? the piston ll is forced in the tube while no needle has pierced the closure 40 or if the canula in a piercing needle is plugged. In order to prevent such expulsion the end of the glass ampoule maybe dipped into a glass etching solution such as hydrofluoric acid, to etch the end of the glass, as indicated at 25'. The solution used is one which does not react chemically with the rubber closure 40. The etched surface 2! extends around theentire periphery of the glass tube adjacent the ,end thereof. Thereafter the outside of the tube is washed clean and may be coated with a film 42 of thermo-plastic material in any desired manner as, for instance, by-dipping the tube into a suitable thermo-plastic medium such as above described. or the tube may be held vertically and the thermo-plastic material may be dropped on' the outer end of the closure plug. If a thick film is desired repeated 'dippings may be resorted to alternating with drying periods. The film 42 extends over the etched surface 2! of the ampoule which constitutes a foundation for the film 42 so that the film holds tenaciously to the end of the glass and thus holds the plug 40 against being forced out of the tube.

This application is a continuation in part of my co-pending application, Serial No. 340,329, filed June 13, 1940.

In compliance with the requirements of the patent statutes I have here'shown and described a few preferred embodiments of my invention. It is, however, to be understood that the invenwithin the tube so that the end of the tube pro- Jects beyond the outer surface of the disc, and a film of self setting air-tight material adhered to the outer surface of the disc and to the adjacent inner periphery of the tube, said film being thickened at its outer edge to constitute an abutment stop to hold the disc against expulsion by pressure within the tube.

4. An ampoule comprising a tubular body of uniform cross section throughout and having a pieroeable closure disc at one end adapted to be pierced by a hypodermic needle, the outermost end of the disc being within the tube, and an abutment ring within the tube and on the outer side of the disc and anchored to the tube for holding gal; disc against expulsion by pressure within the 5. An ampoule for a hypodermic syringe, said ampoule comprising a tubular body having within one end thereof a pierceable closure diaphragm adapted to be pierced by a hypodermic needle, said diaphragm being of rubber-like material which is self sealing to eal around a hypodermic needle piercing the same and to close the needle opening upon retraction of the needle, and means the outside of the diaphragm and sealed and anchoraged to the adjacent tube wall around the entire periphery of the diaphragm, the end of the tube wall being etched, and the film being anchored along its periphery. to the etchedpart of the tube.

6. The method of making an ampoule which comprises inserting into a tube a diaphragm of compressible sealing material of a diameter slightly in excess of the diameter ofthe tube and at a substantial angle to the normal to the longitudinal axis of the tube to permit the passage of fiuid past that diaphragm, sterilizing the tube and the diaphragm by passing superheated steam through the tube holding the tube vertical with the inclined diaphragm end uppermost. placing a closure over the lower end of the tube. filling the tube. and righting the inclined diaphragm.

7. The method of filling and closing a container having a tubular filling opening which comprises,

essence inserting into the opening a disc or compressible sealing material of a size slightly in excess of the size of the tubular opening and at an angle to the axis of the opening so that the disc does not close the opening, then filling the container by passing the filling material through the space between the interior wall oi the tubular opening and the inclined disc, then tilting the disc to a position closing the opening.

8. An ampoule comprising a tubular body and a piston closure in the body adapted to be moved therein to eject the contents thereoi. said piston closure comprising a facing diaphragm oi rubberized material and a backing therefor comprising alternate discs or compressible and incompressible materials, the compressible discs beingradially compressed by and in irictional engagement with the wall oi'the tubularbody, certain of said backing discs providing air apnea to allow for yielding movement or the compressible material as the piston closure is forced into the tube.

'9. The method of sealing a container having a tubular filling opening which comprises, placing a disc of compressible sealing material of a size slightly. in excess 01 the size of the tubular opening entirely within the container and at a substantial angle to the axis of the opening so that the disc does not close the opening, then tilting the disc to a position sealing the opening whereby the disc is positioned across the opening and substantially spaced from the adjacent end of the container, and then forming a second seal at the other end oisaid container.

10. The method of sealing a container having a tubular filling opening which comprises, placing 35 a disc of compressible sealing material of a size slightly in excess of the size of the tubular opening entirely within the container and at a substantial angle to the axis of the opening so that the disc does not close the opening, then tilting the disc to a position sealing the opening by pressing the disc inwardly of the container at an oil-center point on the disc above the center thereof, whereby the disc is positioned across the opening and substantially spaced from the adjacent end of the container, and then forming a second seal at said adjacent end of the container thereby sealing the outer end of said disc from the atmosphere.

11. The method of making an ampolue which comprises inserting into each end of a tube a diaphragm oi compressible sealing material of a diameter slightly in excess of the diameter of the tube, positioning each diaphragm adjacent its end or the tube and at a substantial angle to the normal to the axis of the tube to permit passage the liquid contents, removing the temporary closure, and then turning the second diaphragm to a position normal to the tube axis to efiect a liquid-tight closure of both ends of the tube.

MACK R. FIELDS.

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