Delivery of cisplatin from thermosensitive co-cross-linked chitosan hydrogels

The aim of the present study was to investigate the in vitro cisplatin release from thermosensitive chitosan hydrogels, produced by ionic cross-linking and by ionic/covalent co-cross-linking. For that, two types of cisplatin-loaded hydrogels were prepared: chitosan hydrogels cross-linked with glycerol-phosphate disodium salt (as an ionic cross-linker) and chitosan hydrogels ionic/covalent co-cross-linked (using different amounts of genipin as covalent cross-linker). Both hydrogels were able to be produced in situ at physiologic conditions. Regarding cisplatin release, all hydrogels exhibited a first initial rapid release reaching a maximum at about 3 h. However, the total amount of drug released was only 20% for the ionic hydrogel (without genipin) and about 60–70% for the ionic/covalent co-cross-linked hydrogels. This disparity was explained in terms of the type of cross-linking and hydrogels network structure. Changes in the initial drug loadings (0.6 and 1 mg/mL) as well as in the covalent cross-linker concentrations (0.10% and 0.20%, w/w) did not significantly affect the cisplatin release profiles.