Ocular inserts: Novel approach for drug delivery into eyes

As an isolated organ, it is difficult to study eye from a drug delivery point of view. Ophthalmic drug delivery is extremely interesting and highly challenging attempt.  In recent scenario, most eye-diseases are treated with topical application of eye-drops. But these conventional eye-drops have two major problems. One is it needs frequent administration at every 4 hours or 1 hour if the infection is severe and another is formation of crystalline deposits on cornea due to its pH-dependent solubility which is very low. In order to provide the solution of above problems many novel formulations have been developed. Ocular insert is one of them. Ocular inserts are defined as sterile, thin, multilayered, drug-impregnated, solid or semisolid consistency devices placed into the cul-de-sac or conjuctival sac, whose size and shape are especially designed for ophthalmic application. The review study emphasizes on advantages of ocular inserts over conventional dosage forms. The study includes physiology of eye, various preparation and evaluation methods of ocular inserts.