METHOD OF CONTROLLING PARTICLE SIZE OF RETINOIC ACID NANOPARTICLES COATED WITH POLYVALENT METAL INORGANIC SALT AND NANOPARTICLES OBTAINED BY THE CONTROLLING METHOD

摘要

It is intended to provide a method of controlling the particle size of retinoic acid nanoparticles having relieved irritation, which can be subcutaneously and intravenously administered, is usable as a sustained release preparation, and has such a high skin-permeability as allowing the use thereof as an external preparation such as a drug or a quasi drug as well as a cosmetic to be applied to the skin, etc., and nanoparticles obtained by the controlling method. More specifically speaking, the controlling method comprises dispersing a solution of retinoic acid in a lower alcohol together with an aqueous alkali solution, further adding a nonionic surfactant thereto to give a mixture micell, adding a metal chloride or acetate and an alkali metal carbonate or phosphate at a molar ratio of from 1:0 to 1.0 to thereby form a film of a polyvalent metal inorganic salt on the micell surface, and then regulating the particle size to 5 to 300 nm. As the polyvalent metal inorganic salt, use is made of calcium carbonate, zinc carbonate or calcium phosphate.