Patent ID: 8759322

Claim:
A hyaluronic acid derivative containing a hydrophobic group, comprising at least one repeating unit represented by the formula (I): wherein R 1 , R 2 , R 3 , and R 4 are each independently selected from a hydrogen atom, C 1-6 alkyl, formyl, and C 1-6 alkylcarbonyl; Z represents a direct bond; X 1 is a hydrophobic group selected from the groups represented by the following formulas: —NR b —COO—R, R a , and R b are each independently selected from a hydrogen atom, and C 1-6 alkyl; R is a steryl group; Y is C 2-30 alkylene or —(CH 2 CH 2 O) m —CH 2 CH 2 ; and m is an integer selected from 1 to 100.