Release behavior of a polyanion‐crosslinked chitosan‐poly(N‐isopropylacrylamide) gel thermoresponsive material

ABSTRACT A novel type of temperature‐responsive hydrogel with sensitive release performance of an encapsulated compound was obtained. The temperature‐responsive hydrogel with a sensitive state change between 32 °C and 29 °C was prepared by physically crosslinking chitosan with a polyanion of tripolyphosphate and linear poly( N ‐isopropylacrylamide) (PNIPAAm). Cyanocobalamin was used as a model drug and was encapsulated in the prepared hydrogel. The swelling ratio and release behavior of cyanocobalamin were evaluated. Hydrogels containing 3.0% chitosan and 3.0% PNIPAAm had the best swelling ratio and the maximum amount of released encapsulated cyanocobalamin. The amount of released cyanocobalamin was quantified at 25 °C and 40 °C to evaluate the release behavior. The encapsulated cyanocobalamin remained within the hydrogels at 25 °C and was rapidly released at 40 °C. After 1 min at 40 °C, the released amount was approximately 50% of the encapsulated cyanocobalamin. The temperature‐responsive hydrogels obtained have good performance for use in drug delivery systems. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46732.