Dual-stimuli-responsive hydrogels based on poly(N-isopropylacrylamide)/chitosan semi-interpenetrating networks

The synthesis and characterisation of semi-interpenetrating polymeric networks obtained by the radical-induced polymerisation of N-isopropylacrylamide in the presence of chitosan using tetraethyleneglycoldiacrylate as the crosslinker is described. The influence of the degree of crosslinking and that of the ratio of chitosan to poly(N-isopropylacrylamide) on the “pH/temperature induced” phase transition behaviour and swelling characteristics of the hydrogel system are investigated. The ability of the same system to act as a controlled release vehicle for pilocarpine hydrochloride is evaluated.