ReviewPost screenProtein delivery to the back of the eye: barriers, carriers and stability of anti-VEGF proteins

- Development and delivery of novel anti-VEGF proteins for posterior segment eye disease.
- Several static and dynamic physiological barriers encountered in protein delivery to the back of the eye.
- Strategies for controlled release of protein drugs to the posterior segment includes systems that can be injected as well as implant based systems.
- Preserving the stability of protein therapeutics during drug development and controlled release is crucial as well as challenging.

Utilization of the full clinical potential of many novel therapeutic proteins designed for diseases affecting the posterior segment of the eye has often been limited because of their inherent instability and the difficulty in overcoming various ocular barriers. Intravitreal injection is currently the only approved mode of administration, although it is suboptimal because it is painful and has to be done every 1-2 months as a result of high protein clearance rates from the vitreous humor. In this review, we discuss the status of protein drug delivery to back of the eye in terms of novel protein drugs developed, physiological barriers encountered, strategies for carrier design to overcome these limitations, and protein stability. We focus on the most promising approaches as well as on current shortcomings.