Prevention of experimental proliferative vitreoretinopathy with a biodegradable intravitreal drug delivery system of all-trans retinoic acid

Purpose: To evaluate the antiproliferative effect of an all-trans retinoic acid (at-RA) drug delivery system (DDS) on experimental proliferative vitreoretinopathy (PVR). Methods: PVR was induced in rabbits with core vitrectomy and fibroblast injection. The DDS containing 420 mu g, 650 mu g, and 1,070 mu g of at-RA was implanted into the vitreous of treated groups 13, C, and D, respectively. Group A with no DDS and group E with nonmedicated DDS served as controls. The intravitreal at-RA concentration was measured with high-pressure liquid chromatography. The drug toxicity was evaluated histologically. Results: The severity of PVR was significantly reduced in groups C and D but not in groups A, B, and E. The drug release peaked at 6 weeks to 7 weeks. No signs of retinal toxicity were found in the DDS groups. Conclusion: Intravitreal implantation of at-RA DDS appears effective in inhibiting the development of PVR and is well tolerated in rabbit eyes.