Studies on in situ gelling system for better ocular drug therapy

Currently, very few new ophthalmic drug delivery systems have been commercialized. Effective treatment of ocular diseases is a formidable challenge for scientists in the field especially because of the nature of diseases and presence of the multiple ocular barriers imposed by the eye against the entry of xenobiotics. There is a multiplicity of reasons for increased interest in alternate dosage forms. A basic concept shared by most scientists in ophthalmic research and development is that the therapeutic efficacy of an ophthalmic drug can be greatly improved by prolonging its contact with corneal surface. For achieving this purpose, viscosity enhancing agents such as methyl cellulose are added into eye drop preparations, or the ophthalmic drug is provided as an ointment to sustain the duration of intimate drug/eye contact. Unfortunately, these dosage forms give only marginally more sustained drug/eye contact than the eye drop solutions and do not yield a constant drug bioavailability as originally hoped. Repeated medications are still required throughout the day. As the pharmaceutical companies adjust their strategies to one of disease management, novel drug delivery offers us the capability of developing a series of niche and line extensions to enhance the product line offered around the disease focused. In addition to cost containment, novel drug delivery systems can impart important advantages such as extending the duration of drug activity, which allows greater patient compliance owing to elimination of multiple dosing schedules; reducing side effects due to optimization of the blood concentration-time profile; addressing chronological issues by temporal optimization of dosing and by using feedback control self-regulatory polymers and other systems. The principal categories of products in the ophthalmic market are glaucoma treatments, anti-inflammatories, anti-infectives, surgical adjuncts and artificial tear products. Glaucoma is the leading cause of preventable blindness and Conjunctivitis is the most ...