Intravitreal Devices for the Treatment of Vitreous Inflammation

Abstract

The eye is a well-suited organ for local delivery of therapeutics to treat vitreous inflammation as well as other pathologic conditions that induce visual loss. Several conditions are particularly challenging to treat and often require chronic courses of therapy. The use of implantable intravitreal devices for drug delivery is an emerging field in the treatment of vitreous inflammation as well as other ophthalmologic diseases. There are unique challenges in the design of these devices which include implants, polymers, and micro- and nanoparticles. This paper reviews current and investigational drug delivery systems for treating vitreous inflammation as well as other pathologic conditions that induce visual loss. The use of nonbiodegradable devices such as polyvinyl alcohol-ethylene vinyl acetate polymers and polysulfone capillary fibers, and biodegradable devices such as polylactic acid, polyglycolic acid, and polylactic-co-glycolic acid, polycaprolactones, and polyanhydrides are reviewed. Clinically used implantable devices for therapeutic agents including ganciclovir, fluocinolone acetonide, triamcinolone acetonide, and dexamethasone are described. Finally, recently developed investigational particulate drug delivery systems in the form of liposomes, microspheres, and nanoparticles are examined.

Ocular delivery of proteins and peptides: Challenges and novel formulation approaches

“…Ozurdex (Allergan®) is one such biodegradable PLGA based implant approved by FDA for macular edema and noninfectious posterior uveitis [202]. The PLGA copolymer matrix releases loaded dexamethasone (0.7 mg) in the vitreal cavity for a period of 6 months [203]. A similar formulation has been evaluated for the delivery of brominidine tartrate in clinical trials (NCT02087085).…”

Ocular delivery of macromolecules

“…Ozurdex (Allergan, Irvine, CA) is approved for the treatment of macular edema but has been used off-label for uveitis too [163, 164]. Ozurdex is a biodegradable implant consisting of 0.7 mg of dexamethasone within a PLGA copolymer matrix that is implanted in the vitreal cavity and releases drug for 6 months [165]. The formulation approach used in Ozurdex was also evaluated for delivery of brimonidine tartrate in clinical trials [166].…”

A sustained intravitreal drug delivery system with remote real time monitoring capability

“…[10] To extend vitreous half-life and alleviate the need for frequent injections, a variety of drug delivery systems have been proposed, including liposomes[11], nano/microspheres[12], micelles[13] as well as porous silicon particles[14-16] [17]. With extended residence time in the eye comes a need to understand the complex ocular pharmacokinetics of the drug and delivery system, which demands a large number of animals and significant investment in research effort and resources.…”