In vitro Antibacterial Activity of PLGA-PEG-PLGA Thermosensitive Hydrogels Loaded with Vancomycin

The poly (D, L-lactide-co-glycolide)-poly (ethylene glycol)-poly (D, L-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymer was synthesized via ring opening copolymerization of D, L-lactide (D, L-LA) and glycolide(GA) by PEG(M-n = 1500) as a macromolecular initiator. The chemical structure and composition of the copolymer were determined by H-1 NMR spectra. The sol-gel phase transitions of the PLGA-PEG-PLGA solutions in PBS(pH= 7. 4) were studied by the vial tilting method. The phase-transition temperatures of polymer with different concentrations were from 27 C-omicron to 32 C-omicron, which confirmed by rheology analysis. In addition, the degradation and biocompatibility of the 25% (mass fraction) hydrogels were investigated in vitro. And the results show a satisfied degradation behavior and good cyto-compatibility. Meanwhile, UV-Vis spectroscopy was used to measure the release properties of vancomycin loaded thermosensitive hydrogel. The release of vancomycin lasted to 12 d. The result of antibacterial experiment in vitro indicated that the vancomycin loaded thermosensitive hydrogels possessed excellent antibacterial properties. Therefore, the PLGA thermosensitive hydrogels hold potential as promising platforms for delivery of vancomycin for preventing infections in clinical treatment.