One of the following is a prodrug

Ans. is 'a' i.e. Enalapril Remember, * The end result of drug metabolism is usually the abolition of activity of the drugs and conversion of drug from lipid soluble to water soluble compounds but sometimes the drug may be converted from its inactive form to active form.ProdrugsFew drugs are inactive as such and need conversion in the body to one or more active metabolites. Such a drug is called a prodrug.The prodrug may offer advantage over the active form in being more stable, having better bioavailability or other desirable pharmaco-kinetic properties or less side effects and toxicity.ProdrugActive form* LevodopaDopamine* EnalaprilEnalaprilat* S-methyldopaa methyl norepinephrine* DipivefrinEpinephrine* SulindacSulfide metabolites* Hydrazide MAO inhibitorsHydrazine derivatives* ProguanilProguanil Triazine* PrednisonePrednisolone* BacampicillinAmpicillin* Sulfasalazine5 Aminosalicylic acid* CyclophosphamideAldophosphamide, Phosphoramide mustard* FluorouracilFluoruridine monophosphate* MercaptopurineMethyl mercaptopurine ribonucleotide