Biocompatible poly(N-isopropylacrylamide)-g-carboxymethyl chitosan hydrogels as carriers for sustained release of cisplatin

The therapeutic concentration of cisplatin (CDDP) is usually associated with dose-limiting side effects. To avoid these harmful effects, a biocompatible hydrogel carrier which consisted of poly(N-isopropylacrylamide) and carboxymethyl chitosan was designed to deliver CDDP to the local environment of a solid tumor. The poly(N-isopropylacrylamide)-g-carboxymethyl chitosan hydrogels were synthesized by chemical crosslinking. Scanning electronic microscopy images showed that the hydrogels exhibited a cross-linked structure with the average pore size from 100 to 200 A mu m. Water contact angles and swelling studies suggested that the hydrogels had good hydrophilicity and the lower critical solution temperature lay in the vicinity of 32 A degrees C. The MTT assays implied that the hydrogels were non-cytotoxic on NIH3T3 cells. In vitro release experiment demonstrated that the release of CDDP was controllable and sustained over a long period. Moreover, the released CDDP retained its anticancer activity on A549 cells. The hydrogels are promising carriers for sustained release of cisplatin.