Preparation of cross-linked biodegradable copolymers based polycarbanion of 3-arm PL(D)LA with brominated pluronic and stereocomplex mediated gelation behavior

We overcome rapidly dissolution properties of Pluronic hydrogels by chemical and physical crosslinking synergistic combination of gelation characteristics with polymer thermo-sensitivity. A new class of injectable sol-gel transition hydrogel was successfully prepared using biodegradable cross-linked poly(lactide)-Pluronic copolymers (PL(D)LA-Pluronic) via polycarbanion derived from enantiomeric 3-arm PLA using brominated Pluronic. The presence of enantiomeric PLA segments enables to form intermolecular stereocomplex, resulting in temperature-responsive injectable hydrogels. In contrast to the Pluronic which exhibits the temperature-dependent sol-gel transition at a concentration of 16% (w/v) or higher, the 3-arm PL(D)LA-Pluronic cross-linked stereocomplex copolymers showed much lower critical gelation concentration (~ 10 wt%). The stereocomplex formation was examined by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The elegant design of polymeric configurations and the suitable introduction of enantiomeric properties produced a new type of copolymer that can be widely implemented as injectable hydrogels for drug delivery systems.