Dual-responsive supramolecular hydrogels from water-soluble PEG-grafted copolymers and cyclodextrin.

Novel temperature and pH dual-responsive hydrogels were constructed by inclusion of poly(PEGMA)-co-poly(DMA) with alpha-cyclodextrin in aqueous solution. The temperature- or pH-induced sol/gel transition in the hydrogels was completely reversible. Studies on structure/property relationships show that chain uniformity, graft density and copolymer concentration affect the hydrogel behavior. A dual-responsive mechanism is proposed. The in vitro release of a model drug from this hydrogel was studied. It was found that the release kinetics were greatly accelerated at higher temperature and at acidic pH conditions, indicating potential applications in controlled drug delivery.