MEDICINE FOR COSMETIC AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain a medicine for cosmetic which is excellent in water resistance, processability, miscibility with other components and stability and shows low skin permeability and low toxicity by formulating a specific polymer bearing a UV-light absorbent organic group thereto. SOLUTION: This medicine contains a polymer of formula I (R and R' are each H, an alkali metal, an ammonium and an alkyl; X is a direct linkage and an oxoalkylene bearing an alkylene or 0; Y is a UV-light absorbent organic group; (n) is 2-800). Among compounds of formula I, a compound in which R' is an 8-20C alkyl and a compound in which Y is a group absorbing a light of wavelength of 200-400nm are preferable. As the Y, e.g. groups of formula II and formula III are illustrated. The polymer of formula I is obtained by polymerizing maleic anhydride with a monomer of formula IV.