Ocular Drug Delivery System – An Update Review

Eye being a unique and complex organ the access of exogenous substances to the ocular tissues are restricted by its physiology and defense mechanism. Thus the delivery of therapeutic agents to the ocular tissues is not an easy assignment. Cornea an important component present in eye is protected by very effective protective mechanisms which provide the pharmaceutical scientists a challenge of designing a formulation and delivering it to the targeted sites in sufficient concentrations. Development of newer approaches and novel therapeutic agents continue to provide delivery system a high therapeutic efficacy. Due to the defects in the traditional treatment, and also the therapeutic drug levels in targeted site is not maintained for longer time, the search of new type of ophthalmic approaches and technologies has drawn more and more attentions. In past two decades research in ocular delivery system have been accelerated towards a novel, safe and patient compliance formulation and medical devices to surpass the barriers and maintain the therapeutic level in tissues. Recently various technologies with good efficacy and biocompatibility have also been developed to treat the ocular diseases at both the anterior and posterior portion of eye. Anterior segment approaches for ocular treatment, advances are witnessed through the modulation of conventional topical drops with permeation enhancers and it also includes the development as ointments, gels etc. Several nano-formulations are also introduced for treating the anterior portion of the eye. Furthermore for posterior delivery, research focused immensely towards the development of releasing devices and also nano-formulation. Therefore these novel approaches and devices are easy to formulate, possess negligible irritation, prolonged precorneal residence time, sustained drug release, and enhanced bioavailability. An update of research advancement in ocular drug delivery provides and helps the scientists to modulate and develop safe drug delivery strategies. This review article gives update information about various approaches for delivering the drug to ocular region.