Preparation and release profiles of pH/temperature-responsive carboxymethyl chitosan/P(2-(dimethylamino) ethyl methacrylate) semi-IPN amphoteric hydrogel

摘要

Thermo- and pH-responsive semi-IPN polyam-pholyte hydrogels were prepared by using carboxymethyl chitosan and P(2-(dimethylamino) ethyl methacrylate) with N,N'-Methylenebisacrylamide (BIS) as crosslinking agent.It was found that the semi-IPN hydrogel shrunk most at the isoelectric point (IEP) and swelled when pH deviated from the IEP.Its swelling ratio dramatically decreased between 30 and 50 °C at pH 6.8 buffer solution.It also showed good reversibility.The UV results showed that when the pH values of drug release medium were 3.7,6.8,and 9 at 25 °C,the cumulative release rates reached 83.1,51.5,and 72.2%,respectively.The release rate of coenzyme A (CoA) was higher at 50 °C than 37 and 25 °C at pH 6.8 solution.The release rate decreased with increasing the content of carboxymethyl chitosan at 25 °C in pH 6.8 solution.The results showed that semi-IPN hydrogel seems to be of great promise in pH/temperature drag delivery systems.