PLGA-PEG-PLGA hydrogel for ocular drug delivery of dexamethasone acetate

Aim: This study aims to investigate the suitability of thermosensitive triblock polymer poly-(DL-lactic acid-co- glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA as a matrix material for ocular delivery of dexamethasone acetate (DXA). Methods: The copolymer was synthesized and evaluated for its thermosensitive and gelation properties. DXA in situ gel-forming solution based on PLGA-PEG-PLGA copolymer of 20% (w/w) was prepared and evaluated for ocular pharmacokinetics in rabbit according to the microdialysis method, which was compared to the normal eye drop. Result: The copolymer with 20% (w/w) had a low critical solution temperature of 32 degrees C, which is close to the surface temperature of the eye. The C-max of DXA in the anterior chamber for the PLGA-PEG-PLGA solution was 125.2 mu g/mL, which is sevenfold higher than that of the eye drop, along with greater area under the concentration-time curves (AUC). Conclusion: These results suggest that the PLGA-PEG-PLGA copolymer is potential thermosensitive in situ gel-forming material for ocular drug delivery, and it may improve the bioavailability, efficacy of some eye drugs.