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

摘要

Nanoparticles containing retinoic acid have reduced irritancy of retinoic acid and are suitable for subcutaneous or intravenous administration, as well as for use in sustained-release preparation. The high skin permeability of the nanoparticles makes them suitable for use in pharmaceutical or non-pharmaceutical external preparations or cosmetics intended for skin application. The present invention provides a method for adjusting the particle size of such nanoparticles and nanoparticles produced by such a method. Specifically, the method involves dispersing retinoic acid dissolved in a lower alcohol in an aqueous alkali solution; adding a nonionic surfactant to the dispersion to form a mixed micelle; adding to the micelle a halide or acetate of divalent metal along with a carbonate or phosphate of alkali metal so that the molar ratio of the former to the latter is 1:0 to 1:1.0, thereby depositing a coating of inorganic salt of polyvalent metal on the surface of the micelle; and adjusting the average particle size of the resulting nanoparticles to 5 to 300 nm. The inorganic salt of polyvalent metal may be calcium carbonate, zinc carbonate, or calcium phosphate.