Biodegradable polymeric device for sustained intravitreal release of ganciclovir in rabbits

Purpose. A scleral plug made of biodegradable polymer implanted at the pars plana was evaluated to determine its ability to control the intravitreal release of ganciclovir. Methods. Scleral plugs containing 25% ganciclovir were prepared with poly(lactic-glycolic acid) (molecular weight, 121 kDa). The release of ganciclovir was evaluated in vitro by spectrophotometry. in vivo intravitreal ganciclovir concentrations were measured by high performance liquid chromatography following plug implantation in pigmented rabbits. The biocompatibility of the device was determined by indirect ophthalmoscopy, electroretinography, and light and electron microscopy. Results. The in vitro study showed that the plug released ganciclovir throughout a 10-week period. The in vivo study demonstrated that the plugs maintained the drug concentration in the vitreous in a therapeutic range adequate to treat cytomegalovirus (CMV) retinitis for 12 weeks. No significant retinal toxicity was observed. Conclusions. This study demonstrated that this drug delivery system can potentially be useful to treat CMV retinitis.