Patent ID: 6932984

Claim:
A method for the production of microcapsules for dermal application, wherein the microcapsules consist of a polymer shell and a core made of an encapsulated substance, said method comprising the steps of: (a) dissolving or dispersing the substance in an organic solvent of a kind that is partially miscible in water and is capable of dissolving or dispersing said substance, together with a wall-forming polymeric material selected from the group consisting of a polyacrylate, a polymethacrylate, a cellulose ether, a cellulose ester, and poly(styrene-co-maleic anhydride), to form an organic solution or dispersion; (b) preparing an aqueous continuous phase saturated with said organic solvent and comprising an emulsifier; (c) while agitating, pouring the organic solution or dispersion obtained in (a) into the aqueous continuous phase obtained in (b), to form an emulsion; (d) adding an excess amount of water to the emulsion obtained in (c) for extraction of the organic solvent from the emulsion, thus forming solid microcapsules; and (e) either (i) isolating the microcapsules, washing with water, and drying at a temperature not higher than 20° C., or (ii) immersing the microcapsules in an aqueous solution of alcohol, separating the microcapsules, and drying at a temperature not higher than 20° C.