Patent ID: 8318695

Claim:
A process for preparing a degradation resistant crosslinked hyaluronic acid hydrogel, said process comprising: a) hydrating sodium hyaluronate fibers in a sodium hydroxide solution to produce hydrated sodium hyaluronate fibers; b) mixing the sodium hyaluronate fibers with a tetrafunctional polyethylene glycol-based-epoxide crosslinking agent to create a sodium hyaluronate fiber mixture; c) heating the sodium hyaluronate fiber mixture at a temperature between 40° C. to 70° C. for a time period of between 1 to 10 hours to produce a crosslinked hyaluronic acid hydrogel; and d) reacting the crosslinked hyaluronic acid hydrogel with a monofunctional polyethylene glycol-based pendant to provide a coating; wherein the polyethylene glycol-based pendant coating provides degradation resistance to the crosslinked hyaluronic acid hydrogel, thereby enhancing in vivo longevity the crosslinked hyaluronic acid hydrogel, and wherein the process uses the tetrafunctional polyethylene glycol-based epoxide crosslinking agent as the only crosslinking agent for preparing the degradation resistant crosslinked hyaluronic acid hydrogel.