A prodrug is a drug administered in an inactive or significantly less active form. After administration, it is metabolized in vivo into an active metabolite. This enhances and helps optimize the rate of absorption, distribution, metabolism, and excretion. Prodrugs are usually designed to overcome the obstacle of poor absorption from the gastrointestinal tract and also the action of GI tract enzymes on the drugs. The use of a prodrug strategy increases the selectivity of the drug for its intended target as it can be activated only at its target site by the action of a certain local effector enzyme.