Chitosan-based hydrogel forming at body temperature

Chitosan was dissolved in HCl or HAc solution separately, and mixed with different weight of glycerophosphate disodium salt (GPDS). The viscosity values of these mixed solutions at equably elevated temperature were recorded, and the DSC curve of that mixed solution forming hydro gel at body temperature was obtained. The research results indicate that the viscosity of these mixed solutions increased as the temperature increased, and the rate enlarged suddenly at a given temperature which is the gelating temperature of this solution. The gelating temperature of these mixed solutions lowered as the weight of GPDS increased. If 2.7 g of chitosan and 6.0 g of GPDS were dissolved in 100 mL of HAc solution and this mixed solution was heated at 0.8 degrees C /min, the gelating temperature of this mixed solution reached 42 degrees C in about 25 min. If 2.0 g of chitosan and 6.0 g of GPDS were dissolved in 100 mL of HCl solution and this mixed solution was heated at 0.5 degrees C/min, the gelating temperature of this mixed solution reached 37 degrees C (body temperature) in about 24 min. The DSC result indicates that no exothermal or endothermal fluctuation was observed during the formation of chitosan hydrogel.