In recent years, great interests have focused on in situ gel-forming polymers for therapeutic implants and vehicles.Ctitosan (CS) is an amino-polysaccharide obtained by alkaline deacetylation of chitin, a natural component of shrimp or crab shells.Chitosan is becoming increasingly attractive in the biomedical application and has been used as a vehicle for drug delivery because of its biocompatibility, biodegradability and low toxicity[1].