Regarding drug conversion which of the following is considered as useless

Ans) a ( Inactive drug ...) Ref Goodman and gilman ll'h ed, KDT 7"1 ed, general pharmacologyDirect pick from KDTBiotrasformation means chemical alteration of drug in the body.lt is needed to render nonpolar compounds polar, so that they are not reabsorbed in the renal tubules and are excreated. The primary site for drug metabolism is liver; other are kidney,intestine,lungs and plasma.Biotransformation of drugs may lead to the following and are considered useful1. Inactivation of active drug metabolite2. Active metabolite from an active drug3. Activation of an inactive drugSo coversion of inactive drug to inactive metabolite is useless in biotransformation.Most metabolic biotransformations occur at some point between absorption of the drug into the general circulation and its renal elimination.A few transformations occur in the intestinal lumen or intestinal wall. In general, all of these reactions can be assigned to one of two major categories called phase I and phase II reactionsPhase I reactions usually convert the parent drug to a more polar metabolite by introducing or unmasking a functional group (-OH, -NH2, -SH).Often these metabolites are inactive, although in some instances activity is only modified or even enhanced.Some times phase I undergo a subsequent reaction in which an endogenous substrate such as glucuronic acid, sulfuric acid, acetic acid, or an amino acid combines with the newly incorporated functional group to form a highly polar conjugate.Such conjugation or synthetic reactions are the hallmarks of phase II metabolism.For example, the hydrazide moiety of isoniazid is known to form an /V-acetyl conjugate in a phase II reaction. This conjugate is then a substrate for a phase I type reaction, namely, hydrolysis to isonicotinic acid. Thus, phase II reactions may actually precede phase I reactions.