Abstract

CURRENT TRENDS TOWARDS AN OCULAR DRUG DELIVERY SYSTEM: A REVIEW

Umakant Sharma* and Upendra Nath Nanda

Abstract

Ophthalmic drug delivery is one of the challenging endeavors facing pharmaceutical scientist today. The structural and functional aspects of the eye render this organ highly impervious to foreign substances. A significant challenge to the formulator is to overcome the protective barriers of the eye without causing permanent tissue damage. The major problem encountered with topical administration is the rapid pre-corneal loss caused by naso-lacrymal drainage and high tear fluid turnover which leads to only 10% drug concentrations available at the site of actions. Poor bioavailability of drugs from ocular dosage forms is mainly due to the tear production, non-productive absorption, transient residence time, and impermeability of corneal epithelium. Most ocular treatments like eye drops and suspensions call for the topical administration of ophthalmic drugs to the tissues around the ocular cavity. These dosage forms are easy to instill but have the inherent drawback that the majority of the medication in them is immediately diluted. An update of current research advancement in ocular drug delivery necessitates and helps drug delivery scientists to modulate their think process and develop novel and safe drug delivery strategies. Current review intends to summarize the existing conventional formulations for ocular delivery and their advancements followed by current nanotechnology based formulation developments. Major improvements are required in each of the technologies discussed in this review.

Keywords: Ophthalmic drug delivery, Iontophoresis, Drug delivery, Ocular inserts, Topical ocular.