Xenobiotics are metabolized to ?
Correct Answer: Increase water solubility
Description: Ans. is 'a' i.e., Increase water solubility BIOTRANSFORMATION (METABOLISM) Most of the drugs are treated by the body as foreign substances (xenobiotics). Like other foreign substances (xenobiotics), body tries to eliminate drugs by various mechanisms for ridding itself of chemical intruders. Biotransformation means chemical alteration of the drug in the body. Why drug transformation is necessary ? Kidney plays a pivotal role in terminating the activity of drugs. For renal excretion the drug tends to be polar (lipid insoluble/water soluble) so that it can not diffuse back from tubular lumen and can be excreted. But pharmacologically active organic molecules (drugs) tend to be lipophlic (nonpolar) and remains unionized or only paially ionized at physiological pH. Biotransformation is needed to render nonpolar (lipid soluble) compounds polar (water soluble) so that they are not reabsorbed in the renal tubules and are excreted. Sites and processes of biotransformation Primary site of drug metabolism is liver, others are - kidney, intestine, lung and plasma. Biotransformation of drugs may lead to :- Active metabolite from an active drug Many drugs are paially conveed to one or more active metabolites. The effects observed are the sumtotal of that due to the parent drug and its active metabolite. Activation of inactive drugs Few drugs are inactive as such and need conversion in the body to one or more active metabolites. Such a drug is called prodrug.
Category:
Pharmacology
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