Patent ID: 7893225

Claim:
A sponge consisting of porous network of a crosslinked hyaluronic acid obtained by crosslinking a photoreactive hyaluronic acid to which a photo-crosslinking group having cinnamic acid or aminocinnamic acid as a photoreactive residue is bonded, and having the properties of the following (1), (2) and (3): (1) not less than 30 pores per 39,360 μm 2 among which not less than 50% of said pores have a pore diameter of 10 to 50 μm; (2) a water content calculated from the following formula is not less than 70%; {(Ww-Wd)/Ww}×100 wherein Ww is a weight of the sponge when immersed in an injection water for five seconds; and Wd is a weight of the sponge after completely removing water from the water-immersed sponge using a filter paper, and (3) a breaking strength of the hyaluronic acid sponge, which is prepared from 2 weight % hyaluronic acid solution, is not less than 191.6 g or more than 210.15 g as measured a maximum stress caused when a spherical probe having a diameter of 12.5 mm was pressed against the fixed sponge at a velocity of 1 mm/second by a texture analyzer.