[Ar-CH=CH-COO- (CH2) n-NH-] m-HA, to form a cycloubutane ring, in which Ar represents an optionally substituted phenyl group, n represents an integer of 2 or 3, HA represents a carboxy residue of the hyaluronic acid, and m represents an amidation ratio of the hyaluronic acid to the total carboxyl group and is in the range of 3 to 50% relative to the total carboxyl group. The pharmaceutical composition of the present invention is an intra-articular formulation that exerts rapid analgesic effects after administration, and shows extremely long durable effects for a human joint disease with only a single administration rather than multiple administrations of a conventional way.
