A DRUG-LOADED GEL BASED ON GRAFT RADICAL CO-POLYMERIZATION OF N-VINYLPYRROLIDONE AND 4-VINYLPYRIDINE WITH CHITOSAN

A drug-loaded gel based on chitosan was prepared by radical graft co-polymerization of N-vinylpyrrolidone and 4-vinylpyridine with chitosan and cross-linking by N,N'-methylene-bis-acrylamide. The structure and properties of the hydrogel were characterized by FTIR, XRD and SEM. The surface and morphology of the gel were observed using SEM. The swelling behavior of the prepared hydrogel, with the optimal amount of gelator, was investigated. Also, the in vitro controlled release behavior of doxocyline, as model drug, from the prepared hydrogels, was studied. The release profiles of doxocyline from the hydrogels were determined by UV-Vis absorption measurement under different conditions. The results showed that the new hydrogels exhibit a pH and temperature-responsive swelling ratio, while the pH and temperature were also found to strongly influence the drug release. In addition, the release mechanism of the drug was analysed by fitting the amount of the drug released to the Higuchi, Korsmeyere-Peppas and Hixon-Crowell kinetic models. The drug release occurred through the non-Fickian diffusion mechanism and the release profile was best fitted with the Higuchi square root model.