Self-assembled supramolecular hydrogels formed by biodegradable PLA/CS diblock copolymers and β-cyclodextrin for controlled dual drug delivery

The supramolecular hydrogel based on inclusion complexation between PLA/CS diblock copolymer and β-CD has been demonstrated. The PLA/CS diblock copolymer confirmed by FIIR and 1HNMR were synthesized by in situ polymerization. The supramolecular hydrogel formed due to the complexation of PLA/CS with β-cyclodextrin was demonstrated by XRD and FIIR analysis. These results indicate that the carbonyl groups of PLA can form hydrogen bonds with the hydroxyl groups of β-CD and CS in the complexes. The supramolecular hydrogel presented a porous network structure observed by positive fluorescence microscopy (PFM) was found to be thixotropic and reversibl. The gel kinetics has been studied by monitored the viscosity of the supramolecular system, which was well illustrated according to the Stokes-Einstein equation. The in vitro release kinetics studies of the two model drug from the hydrogel show the co-encapsulation of heparin sodium (HPS) and bovine serum albumin (BSA) exhibits better sustained release behaviors. Furthermore, the release rate of HPS is lower than that of BSA was explored by the two-dimensional UV correlation spectroscopy. The supramolecular hydrogel can be formulated to be a promising candidate for controlled dual drug delivery systems.