CA1338595C

CA1338595C - Gelled emulsion particles and compositions in which they are present

Info

Publication number: CA1338595C
Application number: CA000594608A
Authority: CA
Inventors: Anne Clement; Pierre Fodor; Nathalie Lilienthal; Gerard Guth
Original assignee: Parbel of Florida Inc
Current assignee: Parbel of Florida Inc
Priority date: 1988-03-29
Filing date: 1989-03-23
Publication date: 1996-09-17
Anticipated expiration: 2013-09-17
Also published as: US5738839A; ATE77050T1; DE68901739D1; EP0336817A1; ES2032121T3; BR8901454A; JP2758198B2; JPH0214735A; AU608427B2; US5508022A; US5208028A; EP0336817B1; AU3221489A; DE68901739T2; FR2629363B1; FR2629363A1

Abstract

The present invention relates to gelled emulsion particles obtained when predetermined volumes, especially drops, of an emulsion with an aqueous external phase, containing an appropriate reagent in solution in the said aqueous phase, are added to a gelling solution and left therein for a period of time which depends on the degree of gelling desired for the said particles.
It further relates to compositions - especially solutions, gels or emulsions with an aqueous external phase - in which the said particles are present.

Description

The present invention relates to gelled emulsion particles and to the compositions in which they are present.
According to the invention, the Applicant proposes a novel type of presentation for emulsions with an aqueous external phase. The emulsion particles according to the invention are gelled, at least partially rigidified and individualized in entities of various shapes - especially in the form of spheroidal particles - reversibly if appropriate.
this particular feature of their presentation offers numerous advantages in terms of their use.
The gelled emulsion particles according to the invention can advantageously be used in cosmetology, in pharmacy or in the agri-foodstuffs sector, according to the products which they contain.
In the remainder of the present description, the invention will be described more particularly with reference to the cosmetic sector.
To make cosmetic preparations convenient to use, or even simply for aesthetic reasons, presentation in the form of capsules or spheres has already been used.
The said preparations are inside an envelope or capsule which has to be broken before they can be collected and applied.
In other cases, heterogeneous preparations have been proposed for the inclusion of one or more active ingredients in a chemically unfavorable medium or for the release of these active ingredients at the time of use.
The said active ingredients are trapped in an appropriate material, which is broken by mechanical action.
Where microencapsulation is used, the effect produced on the skin is undetectable; in the case of larger capsules, the envelope remains, bringing the obvious disadvantages.

C ~

2 1338~9S

- Finally, other type~ of co~metic preparation exist in which ~phere~ or drops of cream are included in a gelled and, in particular, tran~parent medium. Thi~ gives the preparation a novel appearance, but the included 05 ~pheres cannot move without the risk of mixing with the gelled medium.
According to the invention, gelled, individualized emul~ion particles are propo~ed which have sufficient rigidity to be included in media of variable vi~cosity, or even to move in media of low viscosity, without the risk of breaking and mixing. Their rigidity i~ sufficiently low, however, for them to be able to be u~ed a~ such or introduced into a medium. Advantageously, they are intro-duced into a medium ~uitable for reducing their rigidity.
They thereby gain flexibility and are capable of mixing very intimately with the ~aid inclu~ion medium when the product i~ taken with the finger and then spread on the ckin or when it pa~es through an appropriate system ~uch a~ a pumping system.
The gelled emulsion particle~ according to the invention are obtained when predetermined volumes of an emulsion with an aqueou~ external pha~e, containing an appropriate reagent in solution in the ~aid aqueou~ pha~e, are added to a gelling solution and left therein for a period of time which depends on the de~ired degree of gelling.
The particles according to the invention can be obtained from any emul~ion with an aqueous external phase.
In the present patent application, emulsion is under~tood a~ meanin8 any type of emulsion with an aqueou~
external pha~e - macroemul~ion or microemul~ion, oil-in-water emulsion or multiple emulsion, with or without emul~ifier - or any other equivalent ~y~tem with an aqueou~ external pha~e, e~pecially a di~per~e sy~tem.
The Raid emul~ion contain~ an appropriate reagent 3 1338~95 in 301ution in its aqueous pha~e. The said reagent i~ at lea~t one compound which, on contact with the gelling solution, cause~ at least partial rigidification of the volumes of emulsion introduced therein.
05 The said gelling ~olution contain~ at least one product capable of reacting with the said reagent con-tained in the emulsion.
The reaction involved is a reaction which instan-taneously generates an insoluble material from two ~oluble compounds, respectively present in the emul~ion with an aqueou~ external phaqe and in the gelling solution The emulsion particle~ are trapped in the ~truc-ture of this insoluble compound.
The consistency of the insoluble entities obtained can obviously vary according to the nature and the concen-tration of the reagent in the emulsion and those of the gelling ~olution.
It also depends on the period of time for which the said entitie~, i.e. the said volume~, are left in the ~aid gelling ~olution.
Different product~ can be obtained according to the invention by varying the ~aid period of time:
- products of the gelatin capsule type which are gelled at their periphery only, over a greater or lesser thickness; or - products gelled and rigidified to the core.
The~e different types of particle~ form an in-tegral part of the invention. ~owever, the particles gelled to the core represent a preferred variant of the invention.
Such particle~, gelled to the core, are advan-tageously obtained after ageing, i.e. after they have been left in contact with the gelling solution for a sufficient period of time to enable the reaction involved to reach equilibrium. Once the said equilibrium has been reached, the particles are perfectly stable.
According to different variants, the addition of the emulsion to the gelling ~olution can be carried out hot or cold. In particular, it i~ carried out hot with 05 vi~cou~ emul~ions uch as creams. The size, shape and consistency of the particle~ can be varied by modifying numerou~ parameters, especially the size of the orifice of the extrusion system, the viscosity of the emul~ion, it~
extrusion temperature, the concentration of the gelling ~olution, etc Thu~ spheroidal particle~ are obtained by adding the emulsion dropwi e. Thi~ i3 a preferred variant of the invention.
According to other variant~, it i~ possible to obtain filament~ or other entities of variou~ shape~.
The said entitie~ can be collected by decantation or filtration.
They can also be kept in the ~olution in which they were prepared, in which case the latter advan-tageou~ly contain~ preservative~.
The compound~ which are ~oluble in the aqueous external phase of the emul~ion and in the gelling ~olution and capable of generating an inqoluble material on contact are preferably salt~ which interact by ion exchange.
The appropriate reagent in the emul~ion with an agueous external pha~e is advantageously selected from products having a polymeric ~tructure and more par-ticularly from product~ having a polysaccharide structure carrying acid group , and mixtureY thereof.
According to the invention, it i~ advantageous to u~e compounds selected from soluble alginates (for example sodium alginate~), soluble carrageenan, ~oluble chitin derivative~ and mixtures thereof.
Such compounds are generally present in a propor-tion of 0.2 to 1.5% by weight in the emul~ion. In fact, ' -5 13~859~

the amount of reagent pre~ent depend~ on the nature of the latter. Thu~, for example, alginate~ are advantageously pre~ent in a proportion of 0.3 to 0.6% and carrage~
in a proportion of about 1%.
05 Examples of compound~ u~ed in the gelling solution for reacting with the ~aid product~ are ~oluble metal salt3, e~pecially alkali metal or alkaline earth metal ~alt~ or mixture~ thereof. Calcium chloride, pota~ium chloride etc. are u~ed in particular.
The gelling ~olution advantageously contains between 0.01 and 0.05 mol/l of ~uch ~alt~.
Tho~e Akilled in the art will know how to optimize the ~aid concentration~ - concentration of the reagent in the emul~ion, concentration of the product used to react with the ~aid reagent in the gelling ~olution - in order to obtain the desired re~ult.
Thu3 gelled emul~ion particle~ according to the invention can advantageou~ly be obtained when predeter-mined volume~, especially drop~, of an emul~ion with an aqueou~ external pha~e, containing Yodium alginate, are added to a ~olution of calcium chloride. The ~aid par-ticle~ are recovered, preferably after ageing, by decan-tation or filtration.
The calcium chloride and the ~odium alginate are in solution. The ~aid sodium alginate in contact with the said calcium chloride generates a ~alt - calcium alginate - who~e qtructure, of the cro~31inked type, cau~e~ the emulsion to solidify or, more preci~ely, trap~ the emul~ion particles.
The time after which the particle~ are recovered i~ advantageou~ly that which allow~ an equilibrium of calcium/~odium ion~ to establi~h between the gelling solution and the ~aid in~tantaneou~ly obtained particle~.
Thi~ ageing time i~ about 8 day~.
The particle~ can al~o be recovered before thi~

6 133859~

ageing time has elapsed, in which case they will be gelled to a lesser extent.
Likewise, gelled emul~ion particles according to the invention are advantageously obtained when predeter-05 mined volumes, especially drops, of an emulsion with anaqueous external phase, containing carrageenan, are added to a solution of potassium chloride. The particles obtained are recovered in the same way, preferably after ageing, by decantation or filtration.
Determination of the parameters of this manipula-tion~- concentration of salt in the gelling solution, concentration of reagent in the emulsion, presence of additives (preservatives if appropriate), total volume of emulsion transferred into the solution, volume of the said solution used, size of the predetermined volumes, residence time, etc. - is within the domain of those skilled in the art.
They will easily be able to vary the said para-meters to give harder or softer particles.
A~ specified above, it is possible according to the invention to obtain gelled particles from any emulsion with an agueous external pha~e. In particular, gelled particles can be prepared with emulsions contA;n;~E amino acids such as arginine, or with emulsions containing di-hydroxyacetone, or with emulsion~ containing vitamin C, and 80 on.
According to the invention, the proposed novel presentation for emulsions with an aqueous external phase improves their ~torage, their introduction and their pre-servation in another medium. Advantageously, the inven-tion will be put into practice when it is desired to store mutually incompatible products in the same container (for simultaneous use~.
The particles of the invention can be obtained with emulsions containing different type~ of active in-gredient~, for example active principle~ of drug~, activeingredient~ of co~metics or even different raw materials in the agri-food~tuffs ~ector. The invention can therefore be utilized advantageou~ly in the pharma-05 ceutical, agri-foodstuffs or co~metic indu~tries.
It wa~ indicated above that the gelled emul~ion particle~ obtained according to the pre~ent invention can be used aA ~uch or introduced into a medium of variable vi~co~ity, ~uch a u~e being po~ible on account of their relative rigidity.
The invention therefore further relate~ to com-po~itionA, e~pecially pharmaceutical, co~metic or agri-foodstuff~ compo~ition~, which contain gelled emul~ion particles Auch a~ de~cribed above.
The ~aid compo~itions actually contain at lea~t one of the ~aid particle~ and advantageously such par-ticle~ obtained from emulsions of different types.
It i8 in fact of particular value to use particle~
of the invention for ~toring volume~ of emul~ion~ con-taining different products, eApecially mutually incom-patible product~, in the ~ame medium, in the ~ame compo-~ition. The~e product~ can thus be ~tored and pre~erved together, without interacting, prior to u~e for a common purpo~e.
A non-limiting example which may be mentioned i~
the po~ibility, afforded by the pre~ent invention, of preparing emulsion particles contA;n;np dihydroxyacetone on the one hand and amino acid~ such a~ arginine on the other, of including the~e two type~ of product in the form of gelled particle~ in a medium and of preserving them therein with no observable color reaction.
The compo~itions contA;n;n~ the gelled particle~
of the invention can con~iAt of ~olutions, gels or emul-~ion~.
The term "emulsion" ha~ the same meaning here a~

8 133859~

previously, i.e. any kind of emulsion, especially a dis-peræion, with an aqueous external phase.
The gel can be obtained from any water-dispersible gelling agent and more particularly from gelling agents 05 having a carboxyvinylic structure (carbomers), or from acrylic polymers, carboxymethyl, ethyl or propyl cellu-loses or xanthan gums.
The gelled particles are introduced into the said compositions simply by mixing. Depending on the desired result, a greater or lesser amount thereof can be intro-duced: for example from 5 to 50% by weight or even more.
The compositions in which gelled emulsion par-ticles of the invention are included advantageously contain a sufficient amount of a base which is capable of producing an "opposite reaction" to that which led to the gelling of the said particles (a reaction which renders the said particles "fragile").
It is possible to use one base or a mixture of at least two bases.
The base iæ selected from bases compatible with the medium which can be used safely and are capable of generating a new, soluble compound from the insoluble gelled particles, especially a new, soluble salt from in-soluble salts such as calcium alginate or potassium carrageenate. It will preferably be selected from the following list of compounds: sodium hydroxide, triethanol-amine, diisopropanolamine, basic amino acids such as arginine and lysine, and mixtures thereof.
To obtain the desired re~ult, from 0.01 to O.lX by weight of base i8 generally present in the inclusion medium for the particles.
However, the~e figure~ are given by way of indi-cation; thoæe skilled in the art will know how to optimize the said amount of base in a particular case.
It is specified here that, in certain particular g I338595 ca~e~, the inclu~ion medium for the ~aid particles may contain a much larger amount of base: thu~ the amount of base required to render the particle~ fragile can be added to a certain amount of ba~e required to neutralize the gel 05 u~ed.
The reactions involved in preparing the particle~
of the invention and rendering them fragile are ~pecified below, in one particular case, by way of example.
In the production of particles, it i~ po~ible to u~e the following reaction:

~odium alginate + CaClz > calcium alginate in which the emulsion particles are trapped.
If the particle~ containing the ~aid calcium alginate are included in a medium containing triethanol-amine (TEA), part of the calcium alginate will be con-~erted to TEA alginate, which i~ a soluble ~alt. Con-sequently, the particles based on calcium alginate loserigidity and are rendered fragile.
Therefore, when a base is pre~ent in the medium into which the gelled particles according to the invention are introduced, their rigidity is seen to decrease and the emulsion returns at least partially to its initial vis-co~ity.
By choo~ing the nature of the bage and determ~ n; ne its proportion, it is possible to ensure that the entitie~
retain their ~hape and their stability in the medium, while becoming extremely flexible. They are then capable of blending into the ~aid medium to generate a perfectly homogeneous product under any kind of mechanical action.
This mean~ in particular that no special effort is re-quired to reconstitute a perfectly homogeneous product in~tantaneou~ly when taking the mixture - medium + gelled lo 1338595 particles within it - and spreading it on the skin.
The heterogeneous mixture - medium + gelled par-ticles within it - can be used in a pump-action bottle. A
perfectly homogeneous mixture, prepared immediately before 05 u~e, i~ obtained simply by actuating the mechanism.
In general, such a mixture can advantageously be used in a container equipped with a diqpensing system which iq such that the said heterogeneous mixture becomes homogeneou~ on pas~ing through the said ~y~tem, the gelled emulsion particles blending into their inclusion medium.
Further advantages and characteri~tic~ of the in-vention will be underqtood more clearly from the following description of Examples of the preparation of gelled emulsion particles according to the invention and their incorporation into an appropriate medium.

I - PrepAr~t;on of the ~m~ ion~
The percentages expressed below are percentages by weight.
AMpr~ emul~ion of the milk type Two phases, A and B, are prepared:

r %
I Stearic acid 1.00 Stearyl alcohol 2.00 Glyceryl isostearate 3.50 I Polysorbate 60 1.20 A I Sorbitan sesquioleate 0 30 I Mineral oil (and) lanolin alcohol 3.00 Dimethicone 1.00 Sgualane 1.50 L

Glycerol 5.00 I Triethanolamine 0.20 B I Sodium alginate 0.50 05 I Demineralized water qs100.00 I Pre~ervative q~
L

C Fragrance qs Pha~es A and B are heated to 75C. The emulsion is prepared by pouring A into B, with ~tirring.
The emulsion is cooled ~lowly. The fragrance i~
added at 40C.
~X~PT.T~ 2: emulsion of the milk type containing dihydroxy-acetone Two phases, A and B, are prepared:

r Sorbitan tristearate 0.50 PEG-40 stearate 1.25 Cetyl palmitate 3.50 Glyceryl stearate 2.00 25 A I Caprylic/capric triglyceride 6.00 Dimethicone 2.00 Tocopherol 3.00 PPG-15 stearyl ether 5.00 L

` -12 1~3859a Glycerol 5.00 I Sodium alginate 0.40 B I Demineralized water q8 100.00 05 I Pre~ervative~ q8 I Dihydroxyacetone 10.00 L

C Fragrance qs Pha~e~ A and B are heated to 75~C. The emul~ion is prepared by pouring A into B, with stirring.
The emulsion i~ cooled 810wly. The fragrance is added at 40C.
RXAMPT.~ 3 emul~ion of the milk type containing L-arginine Two phases, A and B, are prepared:

r %
I Sorbitan tristearate 0.50 PEG-40 stearate 1.25 I Cetyl palmitate 3.50 A I Glyceryl stearate 2.00 I Caprylic/capric triglyceride 6.00 I Dimethicone 2.00 Tocopherol 3.00 PPG-15 stearyl ether 5.00 L
r I Glycerol 5.00 I Sodium alginate 0.40 B I Demineralized water ~8 100.00 Preservatives gs I L-arginine 10.00 L

C Fragrance q8 Phase~ A and B are heated to 75C.
The emulsion is prepared by pouring A into B, with 05 stirring.
The emulsion is cooled ~lowly. The fragrance i~
added at 40C.

~XA~Pr.~ 4: emul~ion of the milk type containing a water-~oluble derivative of vitamin C
Two phases, A and B, are prepared:

I Sorbitan tristearate 0.50 I PEG-40 qtearate 1.25 I Cetyl palmitate 3.50 A I Glyceryl stearate 2.00 Caprylic/capric triglyceride 6.00 Dimethicone 2.00 PP~-15 stearyl ether 5.00 s r Glycerol 5.00 I Sodium alginate 0.40 25 B I Magnesium ascorbylphosphate3.00 Demineralized water qs 100.00 Pre~ervatives qs L

C Fragrance Phases A and B are heated to 75C.
The emulsion is prepared by pouring A into B, with stirring.
The emulsion is cooled slowly. The fragrance is -14 1338~9a added at 40C.

~XA~PT.F. 5: emul~ion of the cream type Two pha~e~, A and B, are prepared:

r %
I PEG-30 ~tearate and glyceryl stearats 6.00 A I Stearyl alcohol 3.00 I Mineral oil 15.00 L
r Sodium alginate 0.40 Glycerol 3 00 i Triethanolamine 0.35 B I Carbomer~934 0.30 Demineralized water q~ 100.00 Pre~ervative~ q8 L

C Fragrance q~

Pha~es A and B are heated to 80C.
The emulsion i~ prepared by pouring A into B, with ~tirring.
The emul~ion i~ left to cool to 50C before the fragrance i~ added.
The emul~ion i~ kept at 50C and u~ed at thi~ tem-perature, in view of it~ visco~ity, for pouring into the gelling solution (see below).
~XA~PT.~ 6: emul~ion of the cream type Two pha~e~, A and B, are prepared:

-1338a95 Sorbitan tristearate 0.50 I PEG-40 ~tearate 1.25 A I Cetyl palmitate 3.00 05 I Glyceryl monostearate (~elf-emulsifying) 3.50 I Mineral oil 16.00 L
r I Carrageenan 1.00 10 B I Glycerol 5.00 Demineralized water qs 100.00 Pre~ervatives q~
L

C Fragrance qq Phaseq A and B are heated to 80C.
The emulqion is prepared by mixing them, with stirring.
The fragrance iq added at 50C.
The emul~ion is kept at 50C and used at this tem-perature, in view of its viscosity, for pouring into the gelling ~olution (~ee below).

II - Pre~Ar~t;on of the eell ino .~olllt;on - Process uqing calcium chloride Calcium chloride 3.33 g Water q~ 1000 g - Process using potassium chloride Potassium chloride 3.70 g Water q~ 1000 g III - Prep~r~t;on of the eel ;nto wh;ch the eelle~
emtll~;on ~rt;cle~ ~cor~; n~ to the ;nvent;o~ Are i ntro~11]ce~

05 - Proce~ u~ing a carboxyvinylic polymer Carbomer 940 0.60 g Triethanolamine ~ q~ pH 6.5 Water and pre~ervative~ q~100 g - Proce~ u~ing an acrylic polymer Acrylate/~teareth 20 3.00 g PEG-20 5.00 g Imidazolidinylurea 0.30 g Triethanolamine 0.30 g Water q~100.00 g IV - ~xtrl~ion of the p~rt;cle~
The emul~ion~ of Example~ 1 to 6 above are intro-duced dropwise into the gelling ~olution.
The emul~ions of Examples 1 to 5 are introduced into the gelling ~olution contAin;ne calcium chloride; the emul~ion of Example 6 i~ introduced into the gelling ~olu-tion containing pota~sium chloride.
Thi~ dropwi~e introduction i~ carried out u~ing a container equipped with a ~ystem of multiple orifice~, provided the rate of introduction into the gelling ~olu-tion i~ con~tant, which i~ a condition for obtaining particles o~ identical dimenqion~.
The operation i8 carried out in the cold (room temperature) for emul-~ion~ of the milk type. If a cream i~ u~ed, heat (50C) has to be applied in order to adju~t the vi~co~ity.
Thi~ operation i~ de~cribed in greater detail below for the ca~e of any one of the emul~ion~ of Example~
1 to 5, by way of illu~tration.

` 17 1338S95 200 ml of an emulsion are run dropwise into 300 ml of a solution of calcium chloride containing 0.03 mol/l.
At e~uilibrium - after 8 days - the equivalent concentration of calcium ions in the particles and in the 05 ~olution i8 equal to 0.018 mol/l. Under these condition~, the particles have a stable rigidity and can be kept in the solution in which they were prepared, if the latter contains preservatives.
If appropriate, the resulting emulsion particle~
are introduced into the gel.
For example, 20% by weight thereof can be intro-duced.
They are introduced into the gel (carboxyvinylic or acrylic polymer containing triethanolamine) after rinsing with demineralized water.
Homogeneity i~ achieved by means of slow stirring;
this can be carried out using any type of mixer provided with an anchor or a planetary system enabling the ~peed of rotation to be adjusted.
Gelled particles, according to the invention, obtained from the emulsions of Examples 2 and 3 above were included in the same gel.
No coloration i8 observed.
The active ingredients do not react with one another, even after several days of accelerated ageing in an oven at 45C.
A reference product containing amino acid and di-hydroxyacetone, on the other hand, very rapidly develops a coloration The gelled particle~ according to the invention can therefore be used to prepare a very stable self-tan product. The said product is actually prepared by the u~er immediately before use, the active product~ being mixed by mechanical action.

Claims

1. A composition comprising (a) particles of gelled emulsion, said particles produced by adding discrete volumes of at least one emulsion to a gelling solution, said emulsion containing at least one active ingredient and having an aqueous external phase containing in solution therein a soluble reagent which produces gelling at least at the peripheries of said discrete volumes upon reaction with said gelling solution and (b) a medium containing a sufficient amount of base to decrease the rigidity of said particles of gelled emulsion, said particles being contained in said medium.

2. A composition according to claim 1 wherein said medium is a solution, gel or emulsion.

3. A composition according to claim 1 wherein said base is selected from the group consisting of sodium hydroxide, triethoxylamine, diisopropylamine, basic aminoacids and mixtures thereof.

4. A composition according to claim 3 wherein said base is triethanolamine.

5. A composition according to claim 1 wherein said soluble reagent comprises at least one compound having a saccharide structure carrying acid groups.

6. A composition according to claim 5 wherein said compound having a saccharide structure is selected from the group consisting of alginates, carrageenans, chitin derivatives and mixtures thereof.

7. A composition according to claim 1 wherein said gelling solution is an aqueous solution of at least one metal salt.

8. A composition according to claim 7 wherein said metal salt is an alkali metal or alkaline earth metal salt.

9. A composition according to claim 7 wherein said salt is calcium chloride or potassium chloride.

10. A composition according to claim 2 wherein said medium is a gel obtained from a water-dispersible gelling agent selected from the group consisting of gelling agents having a carboxyvinylic structure, acrylic polymers, carboxymethyl, carboxyethyl and carboxypropyl cellulose and xanthan gums.

11. A composition according to claim 1 wherein said at least one active ingredient is an active cosmetic ingredient.

12. A composition according to claim 11 wherein said cosmetic ingredient is selected from the group consisting of dihydroxy acetone, amino acids and vitamin C.

13. A composition according to claim 1 wherein said particles of gelled emulsion are obtained from at least two emulsions containing different active ingredients.

14. A composition according to claim 2 wherein said medium is a gel containing triethanolamine, and said particles of gelled emulsion comprise particles containing dihydroxyacetone and particles containing L-arginine.

15. A composition according to claim 1 which is packaged in a container equipped with an appropriate dispensing system, the passage of the said composition through the said system causing the gelled emulsion particles to "blend" into said inclusion medium.

16. A composition according to claim 13 in which the appropriate dispensing system is a pump-action bottle.