Delivery Systems for the Treatment of Proliferative Vitreoretinopathy: Materials, Devices and Colloidal Carriers

Abstract

Proliferative vitreoretinopathy (PVR), the most serious complication causing retinal detachment surgery to fail, is one of the leading causes of vision-loss in developed countries. The pharmaceutical treatment of this disease, located in the posterior segment of the eye, is problematic because it is difficult to achieve effective drug levels in the vitreous and the retina through conventional forms of administration (topical or systemic). Intravitreal injections can deliver drugs to the retina without the side-effects associated with systemic administration. However, because PVR is a long-term complication and the half-life of most drugs in the vitreous cavity is short, repeated injections are needed but this can cause complications. Recent advances in ocular drug delivery methods and the development of novel bioactive compounds could lead to new ways for the treatment of PVR. This review will summarize recent literature concerning intraocular drug delivery of biopharmaceutical agents for the treatment and prevention of PVR.

Corticosteroids and Anti-Complement Therapy in Retinal Diseases

“…Drug release from these systems occurs either by degradation of the polymer or diffusion through a membrane. Even though some intravitreal implants require surgical implantation, bypassing some drug delivery barriers and reducing dosing frequency and associated side effects are some of their advantages (Jaffe et al 2006;Guidetti et al 2008). …”

Nanoparticulate Transscleral Ocular Drug Delivery

“…Metabolic barriers include enzyme systems such as cytochrome P450 and lysosomal enzymes, which have the ability to degrade or detoxify drugs. Mathematical models of posterior segment drug delivery by subconjunctival injection reveal that the dominant pathway for entry into the vitreous is direct penetration, while recirculation or movement from the aqueous to vitreous chambers is not significant [67][68][69][70]. Table 4: Barriers to transscleral drug delivery [66].…”

Basic Research and Clinical Application of Drug Delivery Systems for the Treatment of Age-Related Macular Degeneration

“…Many of these options include liposomes, microspheres, and microcapsules with diameters of 1-1000 μm, as well as nanospheres and nanocapsules with diameters of less than 1 μm, and biodegradable fibrin sealants (Bourges, Gautier, Delie, et al 2003;Bu, Gukasyan, Goulet, et al 2007;Guidetti, Azema, Malet-Martino, et al 2008;Kearns & Williams, 2009). Polymeric microspheres have been used to target the RPE.…”