Microcapsules with an aqueous core containing at least one water-soluble cosmetic or dermatological active principle and cosmetic or dermatological compositions containing them

• US 6,531,160 B2
• Filed: 05/07/2001
• Issued: 03/11/2003
• Est. Priority Date: 05/05/2000
• Status: Expired due to Term

• Current Assignee: L'Oreal SA
• Original Assignee: L'Oreal SA
• Inventors: Biatry, Bruno, Lheureux, Eric
• Primary Examiner(s): Dees, Jose′ G.
• Assistant Examiner(s): Lamm, Marina
• Application Number:
  US09/849,514
• Publication Number:
  US 20020022038A1
• Time in Patent Office: 673 Days
• Field of Search: 424/401, 424/451, 424/455, 424/457, 424/489, 424/490, 424/494, 424/497, 424/498, 424/501, 424/502, 424/59, 424/70.8
• US Class Current: 424/490
• CPC Class Codes: A61K 2800/412 Microsized, i.e. having sizes between 0.1 and 100 microns
• CPC Class Codes: A61K 2800/52 Stabilizers
• CPC Class Codes: A61K 2800/58 Metal complex; Coordination compounds
• CPC Class Codes: A61K 8/11 Encapsulated compositions
• CPC Class Codes: A61K 8/494 with more than one nitrogen as the only hetero atom
• CPC Class Codes: A61K 8/66 Enzymes
• CPC Class Codes: A61K 8/676 Ascorbic acid, i.e. vitamin C
• CPC Class Codes: A61K 9/5026 obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyvinyl pyrrolidone, poly(meth)acrylates
• CPC Class Codes: A61K 9/5042 Cellulose; Cellulose derivatives, e.g. phthalate or acetate succinate esters of hydroxypropyl methylcellulose
• CPC Class Codes: A61P 17/00 Drugs for dermatological disorders
• CPC Class Codes: A61Q 19/00 Preparations for care of the skin

Abstract

The present invention relates to microcapsules with an aqueous core containing at least one water-soluble cosmetic or dermatological active principle, and with a polymeric and/or waxy envelope, in which the said envelope consists

of at least one polymer chosen from polycaprolactone, poly(3-hydroxybutyrate), poly(ethylene adipate), poly(butylene adipate), cellulose esters of at least one C₁-C₄ carboxylic acid, copolymers of styrene and of maleic anhydride, copolymers of styrene and of acrylic acid, styrene-ethylene/butylene-styrene block terpolymers, styrene-ethylene/propylene-styrene block terpolymers and terpolymers of ethylene, of vinyl acetate and of maleic anhydride, and/or

of at least one wax chosen from beeswax, polyglycerolated beeswax, hydrogenated plant oils, paraffin with a melting point above 45° C., and silicone waxes.

Claims

1. Microcapsules with an aqueous core containing at least one water-soluble cosmetic or dermatological active principle, and an impermeable polymeric envelope, an impermeable waxy envelope, or an impermeable polymeric waxy envelope comprising

at least one polymer selected from the group consisting of polycaprolactone, poly(3-hydroxybutyrate), poly(ethylene adipate), poly(butylene adipate), cellulose esters of at least one C₁-C₄ carboxylic acid, copolymers of styrene and maleic anhydride, copolymers of styrene and acrylic acid, styrene-ethylene/butylene-styrene block terpolymers, styrene-ethylene/propylene-styrene block terpolymers and terpolymers of ethylene, vinyl acetate and maleic anhydride,

at least one wax selected from the group consisting of beeswax, polyglycerolated beeswax, hydrogenated plant oils, paraffin with a melting point above 45°

C., and silicone waxes, or

a combination thereof.

2. The microcapsules of claim 1, wherein the cosmetic or dermatological active principle is an unstable active principle which is sensitive to the surrounding physicochemical conditions.

3. The microcapsules of claim 2, wherein the cosmetic or dermatological active principle is selected from the group consisting of free-radical scavengers, detoxifying agents, keratolytic agents, tanning accelerators, depigmenting active agents, UV screening agents, self-tanning active agents, liporegulators, moisturizers, antidandruff agents, optical brighteners, colorants, and mixtures thereof.

4. The microcapsules of claim 3, wherein the cosmetic or dermatological active principle is ascorbic acid or a salt thereof.

5. The microcapsules of claim 1, wherein the concentration of the cosmetic or dermatological active principle in an encapsulated inner aqueous phase is between 0.1% and 50% by weight relative to the total weight of the encapsulated inner aqueous phase.

6. The microcapsules of claim 1, wherein the aqueous core further comprises one or more polyols of low molecular mass.

7. The microcapsules of claim 1, wherein the aqueous core further comprises one or more water-soluble polymers.

8. The microcapsules of claim 1, wherein the weight ratio of the encapsulated inner aqueous phase forming the core of the microcapsules to the wall of the microcapsules is between 0.1/1 and 50/1.

9. The microcapsules of claim 1, wherein the microcapsules have a mean diameter of between 1 μ

m and 1000 μ

m.

10. A cosmetic or dermatological composition comprising the microcapsules of claim 1, in a physiologically acceptable support.

11. The cosmetic or dermatological composition of claim 10, wherein the composition is in a serum, a lotion, an aqueous, aqueous-alcoholic or oily gel, a water-in-oil or oil-in-water emulsion, or anhydrous form.

12. The cosmetic or dermatological composition of claim 10, wherein the envelope is between 0.5% and 10% by weight of the cosmetic composition.

13. A process for manufacturing the microcapsules of claim 1 comprising the following successive steps:

(a) dissolving at least one cosmetic or dermatological active agent in an aqueous phase,

(b) emulsifying the aqueous solution obtained in step (a) in a solution of at least one polymer, at least one wax, or both in a water-immiscible organic solvent,

(c) emulsifying the water-in-oil primary emulsion obtained in step (b) in an aqueous solution,

(d) removing the organic solvent by evaporation so as to obtain an aqueous suspension of microcapsules,

wherein the polymers used in step (b) are selected from the group consisting of polycaprolactone, poly(3-hydroxybutyrate), poly(ethylene adipate), poly(butylene adipate), cellulose esters of at least one C₁-C₄ carboxylic acid, copolymers of styrene and maleic anhydride, copolymers of styrene and acrylic acid, styrene-ethylene/butylene-styrene block terpolymers, styrene-ethylene/propylene-styrene block terpolymers and terpolymers of ethylene, vinyl acetate and maleic anhydride, and

wherein the wax is selected from the group consisting of beeswax, polyglycerolated beeswax, hydrogenated plant oils, paraffin with a melting point above 45°

C., and silicone waxes.

14. The process of claim 13, wherein the water-immiscible organic solvent used in step (b) is selected from the group consisting of dichloromethane, cyclohexane, heptane, 1-chlorobutane and ethyl acetate.

15. The process of claim 13, wherein the aqueous solution in step (c) contains an emulsion stabilizer.

16. The microcapsules of claim 1, wherein the cellulose esters are mixed cellulose esters of two types of carboxylic acid.

17. The microcapsules of claim 1, wherein the concentration of the cosmetic or dermatological active principle in an encapsulated inner aqueous phase is between 5% and 25% by weight relative to the total weight of the encapsulated inner aqueous phase.

18. The microcapsule of claim 1, wherein the weight ratio of the encapsulated inner aqueous phase forming the core of the microcapsules to the wall of the microcapsules is between 0.5/1 and 10/1.

19. The microcapsules of claim 1, wherein the microcapsules have a mean diameter of between 1 μ

m and 50 μ

m.

20. The process of claim 15, wherein the emulsion stabilizer used in step (c) is selected from the group consisting of poly(vinyl alcohol), polyvinylpyrrolidone, styrene-maleic anhydride water-soluble copolymers, carboxymethylcellulose, starch, chitosan and polyacrylic acid.

21. The microcapsules of claim 1, wherein the envelope consists of at least one of the polymers and at least one of the waxes.

22. The microcapsules of claim 1, wherein the silicone waxes are selected from the group consisting of alkyl- and alkoxydimethicones containing from 16 to 45 carbon atoms and alkyl esters of C₁₆-C₄₅ dimethiconol.

23. The microcapsules of claim 1, wherein the silicone waxes are behenoxydimethicones.

24. The microcapsules of claim 1, wherein the silicone waxes are dimethiconol behenates.