Controlled release bevacizumab in thermoresponsive hydrogel found to inhibit angiogenesis

Age-related macular degeneration (ARMD) and intraocular neovascular diseases have been treated clinically by anti-VEGF antibody drug bevacizumab. However, the use of bevacizumab in the treatment of retinal neovascular diseases has been limited due to the short half-life and frequent injections. In this research, novel amphiphilic hydrophilic-hydrophobic block copolymers of methoxy-poly (ethylene glycol)-block-poly (lactic-co-glycolic acid) were synthesized with ring-opening polymerization, and cross-linked with 2,2-bis (2-oxazoline) (BOX). The aqueous solution of the block copolymers can reverse the sol-gel-sol phase transition. After 1 month of intravitreal injection, the histomorphology of a rabbit's retina was preserved, which indicated the mPEG-PLGA-BOX hydrogel had no cytotoxicity in vivo. Released bevacizumab from the mPEG-PLGA-BOX hydrogel inhibited the RF/6A (Maraca mulatta retina epithelial cell) and HUVEC cell growth, and anti-angiogenesis in 3-D cultures, which showed the bioactivity of the anti-VEGF agent, were maintained in the hydrogel within the release process. In conclusion, the mPEG-PLGA-BOX hydrogel had a sol-gel behavior phase transition, and its intraocular biocompatibility and the characteristics of biodegradability and bioactivity appear to be a promising intravitreal injection carrier for bevacizumab delivery.