Mucoadhesive microparticles engineered for ophthalmic drug delivery

Although topical drug delivery is a convenient route of administration to treat various eye diseases, it has serious limitations due to rapid clearance of the formulation from the surface of the eye. In this study, we engineered microparticles for both sustained drug delivery and prolonged residence time on the extraocular surface. Microparticles were fabricated by emulsification using poly(lactic-coglycolic acid) (PLG) and poly(ethylene glycol) (PEG) as the core material and mucoadhesion promoter, respectively. The particle size wascontrolled to beless than l0pni to avoid eyeirritation and foreventual clearance through the lacrimal canals. Invitro mucoadhesion tests showed that PLG microparticles with PEG adhered better to the mucous membrane under the conditions employed in this study compared to the microparticles without PEG. When an aqueous suspension of microparticles with PEG was administered topically to the rabbit eye in vivo, microparticles were seen for up to 30 min on the ocular surface in the cul-de-sac, which was a dramatic increase in residence time as compared to conventional eye drop formulations. We conclude that mucoadhesive microparticles are promising vehicles for ophthalmic drug delivery. (c) 2007 Elsevier Ltd. All rights reserved.