Supramolecular hydrogels formed from biodegradable ternary COS-g-PCL-b-MPEG copolymer with alpha-cyclodextrin and their drug release.

On the basis of the synthesis of novel biodegradable amphiphilic MPEG-b-PCL-grafted chitooligosaccharide (COS-g-PCL-b-MPEG) copolymers, supramolecular hydrogels were fabricated rapidly via their inclusion complexation with alpha-cyclodextrin (alpha-CD) in aqueous solutions. The graft copolymers were characterized by (1)H NMR spectroscopy, gel permeation chromatography (GPC), and fluorescence measurement, and the supramolecular structure of the resultant hydrogels was confirmed by X-ray diffraction measurements. Rheological studies of as-obtained hydrogels indicate that the physical properties could be modulated by controlling the concentration and the graft content of the graft copolymers as well as the molar feed ratio of the graft to alpha-CD. The in vitro release kinetics studies of bovine serum albumin (BSA) entrapped in the hydrogels show that the drug release profiles are dependent on the supramolecular hydrogel compositions.