ABSTRACT
Prodrugs approach has been arguably effective for discovery of numeral clinically used pharmacologically active agents. Prodrug is the end product of active drug moieties, they are so designed that release the parent drug in the body by metabolic conversion. The alkyl ester and amide forms of ketorolac showed higher permeation across the skin than parent drug ketorolac. The prodrugs based targeted action may be achieved by conversion of prodrugs into active therapeutic constituent either through protection of prodrug until it reaches the target or through the stimuli associated with the target which causes the activation of prodrug. Gene-directed enzyme prodrug therapy mainly composed of five segments including nontoxic prodrug, gene coding for enzymes activation, carrier, enzyme and vector. A prodrug approach is one of the favorable strategies used for pharmacologically active agents to improve their solubility, permeability, stability, bioavailability and for sustained and targeted drug delivery.
