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 µm. 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 °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.