An Insight to Ophthalmic Drug Delivery System

Treating various ailments of eye utilizes mostly two strategies i.e. delivery of the therapeutic agent by development of a novel delivery system or by enhancing the permeation of therapeutically active agent by the use of penetration enhancers or by the alteration of its physicochemical properties. Conventional ophthalmic drugs delivery system including eye drops, ointments and gels, are no longer sufficient to treat vision threatening disorders as they delivery drugs only to anterior segment of eye. A major problem in ocular therapeutics is attainment of an optimal drug concentration at the site of action. Poor bioavailability of drugs from ocular dosage forms is mainly due to the pre-corneal loss factors which include tear dynamics, non-productive absorption, transient residence time in the cul-de-sac, and the relative impermeability of the corneal epithelial membrane. This article reviews various novel approaches like in – situ gel, ocular films or ocuserts, nanoparticles, liposomes, niosomes, collagen shields, ionotophorosis, eye implants. These novel approaches have significant technological challenge with a corresponding problem of patient compliance with dosage forms. In near future, a great deal of attention will be paid to develop noninvasive sustained drug release for both anterior and posterior segment eye disorders. Current momentum in the invention of new drug delivery system holds a promise toward much improved therapies for the treatment of vision-threatening disorders.