Patent ID: 7767806

Claim:
A hyaluronic acid modification product, in which one or more polymers are introduced into glucuronic acid moieties in hyaluronic acid or a derivative thereof, the one or more polymers being selected from the group consisting of polylactic acid, polyglycolic acid, and lactic acid-glycolic acid copolymer; wherein said hyaluronic acid modification product has resistance to degradation by hyaluronidase compared with an unmodified hyaluronic acid; and wherein the polymer is bonded to the carboxyl group of the hyaluronic acid or derivative thereof by an amide bond via a spacer, resulting in a repeating structure of the formula (I): where R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrogen atom, a C 1-6 alkyl group, and a C 1-6 alkylcarbonyl group, Ra and Rb are independently selected from the group consisting of a hydrogen atom and a C 1-6 alkyl group, Q is a polymer selected from the group consisting of polylactic acid, polyglycolic acid, and lactic acid-glycolic acid copolymer, and the polymer forms an amide bond with nitrogen at a terminal carboxyl group thereof, A is a single bond, —(CH 2 ) m —, —CH 2 —CH 2 —(O—CH 2 —CH 2 ) m —, or —NHCO—(CH 2 ) n —CONH—, m is an integer of 1 to 10, and n is an integer of 0 to 10; wherein a repeating structure represented by the formula (I) is contained in a molecule of the hyaluronic acid modification product; wherein the molecule of the hyaluronic acid modification product optionally contains a repeating structure of the formula (II): where R 1 , R 2 , R 3 , and R 4 are independently selected from the group consisting of a hydrogen atom, a C 1-6 alkyl group, and a C 1-6 alkylcarbonyl group, Ra and Rb are independently a hydrogen atom or a C 1-6 alkyl group, A is a single bond, —(CH 2 ) m —, —CH 2 —CH 2 —(O—CH 2 —C 2 ) m —, or —NHCO—(CH 2 ) n —CONH—, m is an integer of 1 to 10, and n is an integer of 0 to 10; and wherein carboxylic groups in glucuronic acid moieties of hyaluronic acid or a derivative thereof are modified to give the repeating structures represented by the formula (I) or (II) at a modification rate of 50% or more, of at least one repeating structure of formula (I) and optionally at least one repeating structure of formula (II); or a pharmaceutically acceptable salt thereof.