PHAR 315 Lecture Notes - Lecture 3: Drug Metabolism, Xenobiotic, Biotransformation
23 Feb 2016
School
Department
Course
Professor
Document Summary
If you don"t biotransform hexobarbital (or other lipophilic xenobiotics), it would be excreted so slowly that it would eventually overwhelm and kill you. If xenobiotics undergo biotransformation, their biological effect is altered: importance for pharmacology: some drugs must undergo biotransformation to exert their effect (i. e. pro- drugs). Biotransformation can also help with targeting systems (ex. A cancer drug that is cleaved at its site of action so it isn"t toxic to the rest of the body: importance for toxicity: some xenobiotics must undergo biotransformation before they exert toxic effects. Biotransformation can sometimes be harmful to the person. Enzymes that catalyze the biotransformation reactions are often responsible for determining a drug"s intensity/ duration of action and are key players for toxicity/ chemical tumorigenesis. Example: fish show a lower capacity to metabolize xenobiotics eliminate xenobiotics unchanged across their gills. The aqueous environment also contributes: the xenobiotics they come in contact with are less lipophilic and can"t be absorbed as well.
