Multivesicular liposomes for sustained release of bevacizumab in treating laser-induced choroidal neovascularization

Bevacizumab is an anti-vascular endothelial growth factor drug that can be used to treat choroidal neovascularization (CNV). Bevacizumab-loaded multivesicular liposomes (Bev-MVLs) have been designed and developed to increase the intravitreal retention time of bevacizumab and reduce the number of injection times. In this study, Bev-MVLs with high encapsulation efficiency were prepared by double emulsification technique, and antibody activity was determined. The results revealed that 10% of human serum albumin (HSA) could preserve the activity of bevacizumab. In vitro release of Bev-MVLs appeared to be in a more sustained manner, the underlying mechanisms of Bev-MVLs indicated that bevacizumab was released from MVLs through diffusion and erosion. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that bevacizumab could retain its structural integrity after being released from MVLs in vitro. In vivo imaging was used to evaluate the retention time of antibody in rat eyes, while pharmacokinetic analysis was performed on rabbit eyes. These results indicated that Bev-MVLs exhibited sustained release effects as compared to bevacizumab solution (Bev-S). Bev-MVLs could effectively inhibit the thickness of CNV lesion as compared to Bev-S at 28 days after treatment. Furthermore, these data suggest that Bev-MVLs are biologically feasible to increase the retention time of bevacizumab in vitreous humor. This novel Bev-MVLs may therefore serve as a promising sustained release drug delivery system for the treatment of CNV.