Laser-activated drug implant for controlled release to the posterior segment of the eye

Posterior segment eye diseases such as age-related macular degeneration (AMD), diabetic macular edema (DME) and proliferative vitreoretinopathy (PVR) are serious choric diseases that may result in vision loss. The current standard of care for the posterior segment eye diseases involves frequent intravitreal injections or intravitreally injectable sustained-release implants. However, dosage is not controllable once the implant is inserted in the vitreous, resulting in serious local side effects, such as elevated intraocular pressure and cataract formation. We previously developed a size-exclusive nanoporous biodegradable PLGA capsule and combined with light-activatable drug-encapsulated liposomes, to create a light-activated dose-controllable implant for posterior eye disease treatment. We demonstrated the stability and safety of the implant in rabbit eyes for 6 months. In this study, we focused on the drug release from the dose-controllable implant by laser irradiation both in vitro and in vivo. Drug release kinetics upon laser irradiation were analyzed with two different total dosages. Drug release by laser irradiation in the rabbit eyes was determined by fluorescence intensity. Optical and histology examination confirmed no damage on the retina. The results demonstrated feasibility of using the implant as an on-demand dose-controllable drug delivery system to the posterior segment of the eye.