USE OF POLYAMINO ACID AS HUMECTANT AND COSMETIC OR PHARMACEUTICAL COMPOSITION CONTAINING THE SAME POLYAMINO ACID

摘要

PROBLEM TO BE SOLVED: To provide an agent used for improving moisture retention of the skin or the mucous membrane and applied to the skin or the mucous membrane. SOLUTION: A polyamino acid derivative composed of at least one polyamino acid derivative represented by the formula (I) [wherein X is selected from O, S and NR and R represents hydrogen atom or a straight-chain or branched saturated or unsaturated 1-6C hydrocarbon based group; R1 is selected from hydrogen atom, a straight-chain or branched saturated or unsaturated 1-40C hydrocarbon based group or the like; n is such average number of >=2 recurring units that molecular weight of polyamino acid derivative becomes 200 to 200,000] is used.