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

• US 20020022038A1
• Filed: 05/07/2001
• Published: 02/21/2002
• Est. Priority Date: 05/05/2000
• Status: Active Grant

• Current Assignee: L'Oreal SA
• Original Assignee: L'Oreal SA
• Inventors: Biatry, Bruno, Lheureux, Eric
• Granted Patent: US 6,531,160 B2
• Time in Patent Office: Days
• US Class Current: 424/401
• 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 with a polymeric and/or waxy envelope, characterized in that 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, preferably mixed cellulose esters of two types of 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.

2. Microcapsules according to claim 1, characterized in that the said envelope consists of at least one of the said polymers and of at least one of the said waxes.

3. Microcapsules according to either of the preceding claims, characterized in that the active principle is an unstable active principle which is sensitive to the surrounding physicochemical conditions such as the temperature, the pH, oxygen, the presence of oxidizing agents or of heavy metals, light or UV radiation.

4. Microcapsules according to claim 3, characterized in that the said active principle is chosen from free-radical scavengers and/or detoxifying agents, keratolytic agents, tanning accelerators, depigmenting active agents, UV screening agents, self-tanning active agents, liporegulators, moisturizers, antidandruff agents and optical brighteners or a mixture thereof.

5. Microcapsules according to claim 4, characterized in that the said active principle is ascorbic acid or the salts thereof.

6. Microcapsules according to any one of the preceding claims, characterized in that the concentration of the said active principle in the encapsulated inner aqueous phase is between 0.1% and 50% by weight and preferably between 5% and 25% by weight relative to the total weight of the encapsulated inner aqueous phase.

7. Microcapsules according to any one of the preceding claims, characterized in that the aqueous core also contains one or more polyols of low molecular mass.

8. Microcapsules according to any one of the preceding claims, characterized in that the aqueous core also contains one or more water-soluble polymers.

9. Microcapsules according to any one of the preceding claims, characterized in that the weight ratio of the encapsulated inner aqueous phase forming the core of the microcapsules to the wall of these microcapsules is between 0.1/1 and 50/1 and preferably between 0.5/1 and 10/1.

10. Microcapsules according to any one of the preceding claims, characterized in that the silicone waxes are chosen from alkyl- and alkoxydimethicones containing from 16 to 45 carbon atoms, for instance behenoxydimethicone and alkyl esters of C₁₆ -C₄₅ dimethiconol, for instance dimethiconol behenate.

11. Microcapsules according to any one of the preceding claims, characterized in that they have a mean diameter of between 1 μ

m and 1000 μ

m and preferably between 1 μ

m and 50 μ

m.

12. Cosmetic or dermatological composition containing, in a physiologically acceptable support, the microcapsules with an aqueous core and with a polymeric and/or waxy envelope according to any one of claims 1 to 12.

13. Cosmetic or dermatological composition according to claim 12, characterized in that it is in the form of a serum, a lotion, an aqueous, aqueous-alcoholic or oily gel, a water-in-oil or oil-in-water emulsion, or in anhydrous form.

14. Cosmetic or dermatological composition according to claim 12 or 13, characterized in that the polymer and/or wax concentration in the cosmetic composition is between 0.5% and 10% by weight and preferably between 1% and 5% by weight.

15. Process for manufacturing microcapsules according to any one of claims 1 to 11, comprising the following successive steps consisting

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

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

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

(d) in removing the organic solvent by evaporation so as to obtain an aqueous suspension of microcapsules, characterized in that the said polymers used in step (b) are chosen from the group formed by polycaprolactone, poly(3-hydroxybutyrate), poly(ethylene adipate), poly(butylene adipate), cellulose esters of at least one C₁-C₄ carboxylic acid, preferably mixed cellulose esters of two types of 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 the said waxes are chosen from beeswax, polyglycerolated beeswax, hydrogenated plant oils, paraffin with a melting point above 45°

C., and silicone waxes.

16. Process according to claim 15, characterized in that the water-immiscible organic solvent used in step (b) is chosen from dichloromethane, cyclohexane, heptane, 1-chlorobutane and ethyl acetate.

17. Process according to claim 15 or 16, characterized in that the said emulsion stabilizer used in step (c) is chosen from poly(vinyl alcohol), polyvinylpyrrolidone, styrene-maleic anhydride water-soluble copolymers, carboxymethylcellulose, starch, chitosan and polyacrylic acid.