Purpose
To develop liposomal formulations for the sustained and controlled release of anti-VEGF antibodies to treat neovascularization associated with diabetic retinopathy and wet AMD.
Methods
Stable liposomal formulations were made using a modified lipid hydration and extrusion method. A model fluorescent protein was encapsulated in the liposomes for preliminary studies and evaluation of the vehicle. The liposomes were evaluated based on particle size, surface morphology, percentage drug encapsulation and time of release using dynamic light scattering, transmission electron microscopy, fluorescence spectroscopy and USP4 SOTAX dissolution apparatus, respectively.
Results
The liposomal formulations after extrusion exhibited a narrow size distribution of approximately 100-150 nm in diameter with around 85-92% encapsulation efficiency. From the in vitro drug release studies, we observed a timed release over a period of 6-8 months depending on the composition of the formulation.
Conclusions
Liposomes are non-toxic, biodegradable artificial vesicles composed of phospholipids and cholesterol. Abrishami et al have been able to obtain a sustained release of the anti-VEGF drugs up to a period of 42 days. Currently, we have been successful in encapsulating a model protein into our stable liposomal formulations and attain a controlled release over a period of 6 months in vitro. In the future, we are interested in encapsulating the protein drugs- Avastin and Lucentis to show the efficiency of our drug delivery vehicle. With this study, our efforts would be to decrease the frequency of intravitreal injections from 12 to 2 per year, thereby effectively making the treatment more economical.