Study and preparation of pH and ionic strength sensitive chitosan hydrogel and its controlled delivery on coenzyme A

A kind of novel pH and ionic sensitive chitosan hydrogel CS-GA-ASP was synthesized by crosslinking reaction with chitosan, glutaraldehyde, and aspartic acid as materials. The effect of the content of crosslinking agent, pH, and ionic strength on the swelling ratio was studied. The hydrogel was also used to control release of coenzyme A. It was shown that the content of crosslinking agent, pH, and ionic strength has great effect on the swelling ratio of the hydrogel. Hydrogel can change reversibly well at different pH and ionic strength solution. The results of UV analysis showed that when the pH values of drug release medium were 3.7, 6.8 and 9, the cumulative release rates reached 78%, 92% and 87%, respectively, and the release rate of coenzyme A at pH 6.8 solution was fastest, and release rate at pH 3.7 solution was slowest.