DOUBLE EMULSIONS COMPRISING A GELLED FATTY PHASE

Abstract

The present invention concerns a water-in-oil-in-water emulsion comprising an external continuous aqueous phase and a water-in-oil emulsion in the form of droplets (G1), each droplet (G1) comprising a continuous fatty phase and at least one droplet (G2) comprising an internal aqueous phase, said continuous fatty phase containing at least one gelling agent, said droplets (G1) comprising a shell formed of at least one anionic polymer (PA1) and at least one cationic polymer (PC).

Claims

1. A water-in-oil-in-water emulsion comprising an external continuous aqueous phase and a water-in-oil emulsion in the form of droplets, each droplet comprising a continuous fatty phase and at least one droplet comprising an internal aqueous phase, said continuous fatty phase containing at least one gelling agent, said droplets comprising a shell formed of at least one anionic polymer and at least one cationic polymer, and optionally said droplets comprising a shell formed of at least one anionic polymer, the same as or differing from, and of at least one cationic polymer.

2. The emulsion according to claim 1, wherein the gelling agent is selected from among organic or mineral, polymeric or molecular lipophilic gelling agents; fats solid at ambient temperature and pressure; and mixtures thereof.

3. The emulsion according to claim 1, wherein the gelling agent is selected from the group consisting of: polyacrylates; esters of sugar/polysaccharide and fatty acid(s), esters of inulin and fatty acid(s), esters of glycerol and fatty acid(s); polyamides; and mixtures thereof.

4. The emulsion according to claim 3, wherein the gelling agent is selected from the group consisting of: dextrin palmitates, dextrin myristates, dextrin palmitates/ethylhexanoates, and mixtures thereof.

5. The emulsion according to claim 1, wherein the gelling agent is selected from the group consisting of: optionally modified clays, silicas, and mixtures thereof.

6. The emulsion according to claim 1, comprising from 0.5% to 99.99% by weight of gelling agent(s) relative to the total weight of the fatty phase of droplets.

7. The emulsion according to claim 1, wherein the fatty phase of droplets comprises at least one oil selected from the group consisting of: hydrocarbon oils of vegetable origin, hydrocarbon oils of animal origin, synthetic esters and ethers, straight-chain or branched hydrocarbons of mineral or synthetic origin, silicone oils, fatty alcohols having 8 to 26 carbon atoms, partly hydrocarbon and/or silicone fluorinated oils and mixtures thereof.

8. The emulsion according to claim 1, comprising from 0% to 99.49% by weight of oil(s) relative to the total weight of the fatty phase of droplets.

9. The emulsion according to claim 1, wherein the anionic polymer(s), and optionally the anionic polymer(s), are polymers comprising monomeric units having at least one carboxylic acid function.

10. The emulsion according to claim 1, comprising from 0.01% to 5% by weight of anionic polymer(s), and optionally of anionic polymer(s) relative to the total weight of said emulsion.

11. The emulsion according to claim 1, wherein the cationic polymer has the following formula (I): ##STR00004## wherein: R.sub.1, R.sub.2 and R.sub.3 are each independently OH or CH.sub.3; R.sub.4 is a CH.sub.2 group or XNH group where X is a C.sub.3 or C.sub.4 divalent alkylene radical; x is an integer between 10 and 5 000; y is an integer between 2 and 1 000; and z is an integer between 0 and 10.

12. The emulsion according to claim 1, comprising from 0.01% to 10% by weight of cationic polymer(s) relative to the total weight of the fatty phase of droplets.

13. The emulsion according to claim 1, wherein the volume fraction (IF/(IF+MF)) is between 0.1 and 0.7, where: IF is the total volume of droplets, and MF is the total volume of droplets.

14. The emulsion according to claim 1, wherein the internal aqueous phase of droplets comprises at least one additional compound and/or active substance.

15. The emulsion according to claim 1, further comprising at least one active substance selected from among hydrating agents, healing agents, depigmenting agents, UV filters, peeling agents, antioxidants, active substances stimulating the synthesis of dermal and/or epidermal macromolecules, dermo-relaxants, anti-perspirants, soothing agents, anti-age agents, fragrances and mixtures thereof.

16. The emulsion according to claim 1, wherein the size of droplets is greater than 500 m and/or the size of droplets is greater than 10 m.

17. The emulsion according to claim 1, said emulsion not containing any surfactant.

18. A method for preparing an emulsion according to claim 1, comprising the following steps: a) placing an aqueous fluid FE1 in contact with an oily fluid F1; b) forming a water-in-oil emulsion composed of droplets, formed by aqueous fluid FE1, dispersed in a fatty phase formed by fluid F1; and c) forming droplets, each droplet being composed of at least one droplet, by contacting the water-in-oil emulsion obtained at step b) with an aqueous fluid FE2; wherein: the aqueous fluid FE1 at least comprises water and optionally at least one anionic polymer; the oily fluid F1 comprises at least one gelling agent and at least one cationic polymer, and optionally at least one oil; and the aqueous fluid FE2 at least comprises water and at least one anionic polymer, the same as or differing from the anionic polymer.

19. The method according to claim 18, wherein at least the fluid F1, even aqueous fluid FE1, are heated to a temperature of 40 C. to 150 C. to perform step a), even steps b) and c), and optionally fluid FE2 is heated to a temperature of 40 C. to 150 C. to perform step c).

20. A composition comprising at least one emulsion according to claim 1 and a physiologically acceptable medium.

21. A non-therapeutic method for the cosmetic treatment of keratinous material comprising at least one step to apply onto said keratinous material at least one emulsion according to claim 1 or at least one composition according to claim 20.

22. (canceled)

23. A method for encapsulating at least one hydrophilic compound, and optionally at least one lipophilic compound, comprising contacting said hydrophilic compound with a water-in-oil-in-water emulsion, comprising an external continuous aqueous phase and a water-in-oil emulsion in the form of droplets, each droplet comprising a continuous fatty phase and at least one droplet comprising an internal aqueous phase, said droplets and being such as defined in claim 1.

Description

EXAMPLES

Example 1: Double Emulsion of the Invention with a Heat-Sensitive Gelling Agent in the Fatty Phase of Droplets (G1)

[0376] Below, composition of the external aqueous phase (OF), fatty phase (MF) and internal aqueous phase (IF):

TABLE-US-00001 Phase Trade name Supplier INCI name % w/w Phases OF EXTERNAL AQUEOUS GEL PHASE sub-total 100.00 Osmosed water / Aqua Q.S.* Microcare PE THOR Phenoxyethanol 0.93 Microcare PTG THOR Pentylenglycol 2.33 Glycerine codex INTERCHIMIE Glycerin 17.49 (99%) EDETA BD BASF Disodium EDTA 0.04 Tego carbomer 340 EVONIK Carbomer 0.09 FD Carbopol Ultrez 21 LUBRIZOL Acrylates/C10-30 Alkyl Acrylate 0.20 Polymer Crosspolymer Zemea propanediol DUPONT TALE ET Propanediol 5.83 LYLE Butylene glycol INTERCHIMIE Butylen glycol 5.83 Sodium Hydroxide PANREAC Sodium Hydroxyde 0.01 Pellets PRS codex MF OILY PHASE sub-total 100.00 DUB ININ Grade A STERAINERIE Isononyl Isononanoate 38.31 DUBOIS Rheopearl KL2 MYOSHI EUROPE Dextrin palmitate 20.00 DUB DPHCC STEARINERIE Dipentaerythrityl hexacaprylate/ 38.27 DUBOIS hexacaprate Fragrance Fragrance 3.24 CAS-3131 NUSIL Amodimethicone 0.18 IF INTERNAL AQUEOUS GEL PHASE sub-total 100.00 Osmosed water / Aqua Q.S. Microcare PE THOR Phenoxyethanol 0.93 Microcare PTG THOR Pentylenglycol 2.33 Glycerine codex INTERCHIMIE Glycerine 17.49 (99%) EDETA BD BASF Disodium EDTA 0.04 Carbopol Ultrez 21 LUBRIZOL Acrylates/C10-30 Alkyl Acrylate 0.20 Polymer Crosspolymer Zemea propanediol DUPONT TATE ET Propanediol 5.83 LYLE Butylene glycol INTERCHIMIE Butylene glycol 5.83 Sodium Hydroxide PANREAC Sodium Hydroxide 0.01 Pellets PRS codex Unicert Blue 05601-J Sensient CI 42090 0.00078 *Quantum Satis - sufficient quantity.

[0377] Below, composition of the sodium hydroxide solution (BF):

TABLE-US-00002 Trade name Supplier INCI name % w/w BF Osmosed water Q.S. Sodium Hydroxide PANREAC Sodium Hydroxide 0.42 Pellets PRS codex Total 100.00

[0378] The preparation of each of the above phases lies within the general reach of skilled persons.

[0379] The proportions of the different phases of the final emulsion (PF) are given in the table below.

TABLE-US-00003 % phases in PF IF 9.25% MF 9.25% OF 76.51% BF 4.99%

[0380] Experimental Device:

[0381] The equipment required to produce the emulsion in Example 1 is composed of: 4 syringe pumps (one for OF, MF, IF and BF), a syringe heater (for MF), a thermostatic bath, a concentric design 3-way microfluidic device (or nozzle) having coaxial outlets with, from the innermost channel to the outermost channel: [0382] the first channel is dedicated to IF throughput; [0383] the second channel is dedicated to MF throughput; and [0384] the third channel is dedicated to OF throughput.

[0385] The nozzle and the line conveying the oily phase (MF) are placed in a thermostatic bath heated to 85 C.

[0386] The microfluidic device is also adapted to add a sodium hydroxide solution (BF) after formation of droplets (G1) and (G2) for enhancement of OF viscosity.

[0387] The flow rates, from the outermost channel to the innermost channel of the nozzle, under consideration for the different phases are the following: [0388] OF: 76.70 mL/hr, [0389] MF: 10.190 mL/hr, [0390] IF: 9.273 mL/hr, et [0391] BF: 5.000 mL/hr.

[0392] An emulsion according to Example 1 is of particular interest first in that it ensures particularly satisfactory encapsulation of the hydrophilic compounds by means of droplets (G2) but also of lipophilic compounds by means of droplets (G1). Secondly, the droplets (G1) and (G2) are macroscopic and monodisperse, and each droplet (G1) comprises a single droplet (G2). The emulsion is therefore given unique visual appearance. In addition, the emulsion is provided with a texture that is unique in the field of double emulsions which, for obvious reasons, meets continuing demand by consumers in this respect.

[0393] Also, the emulsion in Example 1 is of particular interest with regard to kinetic stability. Droplets (G1) additionally have satisfactory mechanical strength. An emulsion according to Example 1 is therefore able to remain stable over a timescale longer than 3 months, even longer than 6 months at 25 C. despite the absence of a shell for droplets (G2).

[0394] Optionally, the IF described above may also comprise a cationic polymer (PA2), in particular Carbomer Tego 340FD dEVONIK in a content of 0.10 weight % relative to the total weight of IF. The presence of this cationic polymer (PA2) in IF is advantageous in that it allows reinforcing of the kinetic stability of the emulsion of the invention, in particular the mechanical strength of droplets (G2).

[0395] Alternatively, Rheopearl KL2 (INCI: Dextrin palmitate) can be replaced by Rheopearl MKL2 (INCI: Dextrin Myristate). The resulting oily phase (MF), and hence the end emulsion obtained, has the advantage of displaying improved transparency.

[0396] Also, the oily phase (MF) may additionally comprise at least one phenyl silicone oil (e.g. phenyltrimethicone, and better still a diphenylsiloxyphenyltrimethicone (INCI: Diphenylsiloxy Phenyl Trimethicone)) which further improves the transparency of droplets (G1) comprising a gelling agent of Rheopearl KL2 and/or Rheopearl MKL2 type, and therefore improves the transparency of the final composition.

Example 2: Double Emulsion of the Invention with a Thixotropic Gelling Agent in the Fatty Phase of Droplets (G1)

[0397] Below, composition of the external aqueous phase (OF), fatty phase (MF) and internal aqueous phase (IF):

TABLE-US-00004 % w/w Phase Trade name Supplier INCI name Phases OF EXTERNAL AQUEOUS GEL PHASE sub-total 100.00 Osmosed water / Aqua Q.S. Microcare PE THOR Phenoxyethanol 0.80 Microcare PTG THOR Pentylenglycol 2.00 Glycerine codex (99%) INTERCHIMIE Glycerin 20.00 EDETA BD BASF Disodium EDTA 0.04 Tego carbomer 340 FD EVONIK Carbomer 0.25 Sodium Hydroxide / Sodium Hydroxide 0.11 Pellets PRS codex MF OILY PHASE sub-total 100.00 Myritol 318 Ami Chimie CAPRYLIC CAPRIC 96.80 TRIGYLCERIDE Aerosil R974 Azelis SILICA DIMETHYL 3.00 SILYLATE CAS-3131 NUSIL Amodimethicone 0.20 IF INTERNAL AQUEOUS GEL PHASE sub-total 100.00 Osmosed water / Aqua Q.S. Microcare PE THOR Phenoxyethanol 0.80 Microcare emollient PTG THOR Pentylenglycol 2.00 EDETA BD BASF Glycerin 0.04 Glycerine Codex 99% Interchimie Disodium EDTA 20.00 10% sodium hydrox. sol. / Acrylates/C10-30 Alkyl 0.11 Acrylate Crosspolymer Unicert Blue 05601-J Sensient CI 42090 0.45 0.1%

[0398] The preparation of each of the above phases lies within the general reach of skilled persons.

[0399] The proportions of the different phases of the final emulsion (PF) are given in the table below.

TABLE-US-00005 % phases in PF IF 3.57% MF 10.71% OF 85.71%

[0400] Experimental Device:

[0401] The equipment required to produce the emulsion in Example 2 is the same as used for Example 1, with the exception that Example 2 does not have recourse to the use of a syringe heater or thermostatic bath.

[0402] The flow rates under consideration for the different phases are the following: [0403] OF: 120 mL/hr, [0404] MF: 15 mL/hr, and [0405] IF: 5 mL/hr.

[0406] An emulsion according to Example 2 is of particular interest first in that it ensures satisfactory encapsulation of hydrophilic compounds by means of droplets (G2) but also of lipophilic compounds by means of droplets (G1), and secondly it is provided with unique visual appearance and texture in the field of double emulsions which, for obvious reasons, meets growing demand by consumers in this respect.

[0407] In addition, an emulsion according to Example 2 is of particular interest with regard to kinetic stability since droplets (G1) have sufficient mechanical strength to remain intact over a timescale longer than 3 months, even longer than 6 months at 25 C.

[0408] Optionally, the IF described above may further comprise a cationic polymer (PA2), in particular Carbomer Tego 340FDby 'EVONIK in a content of 0.10 weight % relative to the weight of the IF. The presence of this cationic polymer (PA2) in IF is advantageous in that it allows further reinforcing of the kinetic stability of the emulsion of the invention, in particular the mechanical strength of droplets (G2).