Microcapsules comprising sunscreen agents

Abstract

Microcapsules comprised of a core comprising one or more sunscreen agents and a shell of a wall-forming polymeric material, which are non-rupturable upon rubbing or pressing on the skin, and processes of preparing same are disclosed. Topical formulations comprising the microcapsules, which can be, for example, sunscreen formulations or skin care formulations, are also provided.

1 . A microcapsule comprising a core comprising at least one sunscreen agent and a shell enveloping the core, the shell being comprised of a wall-forming polymeric material comprising at least one polymer or copolymer selected from the group consisting of a polyacrylate, a polymethacrylate, a cellulose ether, a cellulose ester, or any combination thereof, said shell being devoid of a plasticizer, the microcapsule being non-breakable when subjected to homogenization at 2000 rpm for 10 minutes and/or to ultrasonication at 15 W and 28 kHz for 1 minute, and is having a size within a range selected from about 1 μm to about 100 μm. 
     
     
         2 - 4 . (canceled) 
     
     
         5 . The microcapsule of  claim 1 , wherein the shell is transparent. 
     
     
         6 . The microcapsule according to  claim 1 , wherein the sunscreen agent is a water insoluble or water immiscible sunscreen agent. 
     
     
         7 . The microcapsule according to  claim 6 , wherein the sunscreen agent is selected from the group consisting of TiO 2 , avobenzone, p-aminobenzoic acid, bemotrizinol, benzophenone-9, bexophenome-3, bisoctrizole, 3-(4-methylbenzylidene)-camphor, cinoxate, diethylamino hydroxybenzoyl hexyl benzoate, dioxybenzone, drometrizole trisiloxane, ecamsule, ethylhexyl triazone, homosalate, menthyl anthranilate, octocrylene, octyl salicylate, iscotrizinol, isopentenyl-4-methoxycinnamate, octyl-dimethyl-p-aminobenzoic acid, octyl-methoxycinnamate, oxybenzone, polysilicone-15, trolamine salicylate, ZnO, and any combination thereof. 
     
     
         8 . The microcapsule according to  claim 7 , wherein the sunscreen agent is TiO 2 . 
     
     
         9 . (canceled) 
     
     
         10 . The microcapsule according to  claim 7 , wherein the sunscreen agent is avobenzone. 
     
     
         11 - 12 . (canceled) 
     
     
         13 . The microcapsule according to  claim 7 , wherein the sunscreen agent is a blend of TiO 2  and one or more of avobenzone, p-aminobenzoic acid, cinoxate, dioxybenzone, ecamsule, homosalate, menthyl anthranilate, octocrylene, octyl salicylate, octyl-methoxycinnamate, oxybenzone, trolamine salicylate, or ZnO. 
     
     
         14 - 15 . (canceled) 
     
     
         16 . The microcapsule according to  claim 1 , wherein the amount of the wall-forming polymeric material is within a range selected from about 20% to about 70%, from about 20% to about 50%, from about 20% to about 40%, or from about 20% to about 30%, or about 20% or 50%, by weight. 
     
     
         17 . (canceled) 
     
     
         18 . The microcapsule according to  claim 1 , further comprising a photostabilizer. 
     
     
         19 . The microcapsule according to  claim 18 , wherein the photostabilizer is selected from the group consisting of diethylhexyl-2,6-naphthalate, octocrylene, ethylhexyl methoxycrylene and 4-methylbenzylidene camphor. 
     
     
         20 . The microcapsule according to  claim 18 , wherein the amount of the photostabilizer in the microcapsule is within a range selected from about 5% to about 50%, from about 5% to about 40%, from about 5% to about 30%, or from about 10% to about 25%, or about 10% by weight. 
     
     
         21 - 22 . (canceled) 
     
     
         23 . A composition comprising a plurality of microcapsules, at least a portion of the microcapsules comprising a plurality of sunscreen agent-containing microcapsules according to  claim 1 . 
     
     
         24 . The composition of  claim 23 , wherein the microcapsules in the plurality of sunscreen agent-containing microcapsules are the same or different. 
     
     
         25 . (canceled) 
     
     
         26 . The composition according to  claim 23 , further comprising a photostabilizer. 
     
     
         27 . The composition according to  claim 23 , wherein at least a portion of microcapsules in the plurality of sunscreen agent-containing microcapsules further comprise a photo stabilizer. 
     
     
         28 . A process of preparing sunscreen agent-containing microcapsule of  claim 1 , the process comprising:
 (a) mixing a solution comprising the sunscreen agent, a wall-forming polymeric material and an organic solvent, to thereby obtain a homogeneous solution;   (b) mixing the homogeneous solution with an aqueous solution containing an emulsifier, under high shear stirring, to thereby form an emulsion; and   (c) adding to the formed emulsion an amount of water which initiates extraction of the organic solvent from the emulsion, thereby obtaining the microcapsules.   
     
     
         29 . The process of  claim 28 , further comprising isolating the microcapsules. 
     
     
         30 . The process of  claim 28 , further comprising drying and sifting the microcapsules, to thereby obtain a free flowing powder of the microcapsules. 
     
     
         31 - 32 . (canceled) 
     
     
         33 . A cosmetic or cosmaceutical formulation comprising the composition according to  claim 23 . 
     
     
         34 . The cosmetic or cosmaceutical formulation according to  claim 33 , further comprising a cosmetically or cosmaceutically acceptable carrier.