| 초록 |
Polyethylene glycol – poly glycolide - ε-caprolactone (PCGA-PEG-PCGA) triblock copolymers were synthesized via a ring opening polymerization from polyethylene glycol, glycolide and ε-caprolactone with stannous octoate was used as a catalyst to made the temperature sensitive hydrogels copolymer. Oligomer sulfamethazine (OSM) was conjugated to PCGA-PEG-PCGA to make OSM- PCGA-PEG-PCGA-OSM by using the coupling polymerization between carboxyl acid end group of OSM and hydroxyl end group of PCGA-PEG-PCGA. 4-(dimethylamino) pyridine (DMAP) and 1,3-dicyclohexyl-carbodiimide (DDC) were used as catalysts in solution polymerization with dichloromethane as the solvent. Their physicochemical properties were investigated by using 1H-NMR spectroscopy and gel permeation chromatography. Sol-gel phase transition of OSM- PCGA-PEG-PCGA-OSM aqueous solution were investigated by remain stable method and injection method. Aqueous solution of OSM- PCGA-PEG-PCGA-OSM changed from a sol phase to a gel phase with increasing temperature and decreasing pH when their polymer concentrations are above a critical gel concentration. The sol-gel transition properties of these block copolymers are influenced by the hydrophobic/hydrophilic balance of the copolymer, block length, hydrophobicity, stereo-regularity of the hydrophobic of the block copolymer, and the ionization of the pH function groups in the copolymer depended on the changing of environmental pH. |
