[Progress in sustained-release drug delivery system for treatment of posterior segment eye diseases]

There is an urgent requirement to find effective therapeutic procedures for the treatment of refractory eye diseases of posterior segment such as posterior uveitis, proliferative vitreoretinopathy, and macular edema associated with diabetes and retinal vein occlusion. Due to systemic side effect developed from systemic drug administration and the low efficiency of topical drug administration, implantable drug devices for the treatment of posterior segment diseases have been explored. In recent years, three different intraocular implantable devices (ganciclovir, fluocinolone acetonide and dexamethasone) have been approved by FDA and showed exciting clinical efficacy. However, these devices have surgical complications and the drug-related side effects. Recently, transscleral drug delivery to the posterior segment has been investigated. Transscleral drug delivery has advantages of large scleral surface area, better safety profile, easily drug administration and could evolve into an effective route with the use of novel biomaterials and the study of drug delivery methods.