A large number of therapeutic medications have undesirable properties that may generate pharmacological, pharmaceutical, or pharmacokinetic barriers in clinical drug applications. Metabolism of drugs by Phase-I & Phase-II metabolic pathways for possibility of active metabolites, which could in turn useful for rational designing of bioprecursor prodrugs of the active principle of interest. This review summarizes various approaches & development of drugs, namely bioprecursor prodrugs and active metabolites related to bioprecursor prodrugs.