Toxicity evaluation of biodegradable and thermosensitive PEG-PCL-PEG hydrogel as a potential in situ sustained ophthalmic drug delivery system.

In this work, a biodegradable poly(ethylene glycol)-poly(epsilon-caprolactone)-poly (ethylene glycol) (PEG-PCL-PEG, PECE) triblock copolymer was successfully synthesized, which was flowing sol at low temperature and turned to nonflowing gel at body temperature. The toxicity evaluation of PECE hydrogel as a potential in situ sustained opthalmic drug delivery system was performed, including the biodegradability of PECE hydrogel in the eye, its effect on cultured human lens epithelia, intraocular pressure, and ocular tissues. The results indicated that the prepared PECE hydrogel was biocompatible and biodegradable despite of temporary elevated intraocular pressure and slight corneal endothelial damage at specific concentration. Therefore, PECE hydrogel may be a safe candidate for sustained ophthalmic drug delivery system.