HLSC 3P19 Lecture Notes - Lecture 1: Portal Vein, Active Metabolite, Biotransformation
15 Dec 2019
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Additional notes on pharmacokinetics: metabolism and excretion of drugs. Drug metabolism and excretion are responsible for the decline of the plasma drug concentration over time. Both processes contribute to the elimination of active drug from the body. Clearance: measure of the rate of elimination (of active drug) Biotransformation or drug metabolism is the enzyme-catalyzed conversion of drugs to their metabolites: most drug biotransformation takes place in the liver, however, drug-metabolizing enzymes are found in many other tissues, gut, kidneys, brain, lungs and skin. Drug metabolizing enzymes have a fundamental role: inactive and detoxify drugs and other foreign compounds (xenobiotics) that can harm the body. Drug metabolites are usually more water soluble than the parent molecule and more readily excreted by the kidneys. Relationship between biotransformation and pharmacological activity: not particularly, some drug metabolites are active, whereas others are inactive. Many drug molecules undergo attachment of polar groups, a process called conjugation for more rapid excretion.
