BIOLOGY 445 Lecture Notes - Lecture 5: Pharmacotherapy, Ion, Hypoalbuminemia
18 Sep 2017
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Pharmacology lecture 5a- pharmacokinetics ii: describe the two phases of drug metabolism. Phase i: modification- usually convert the parent drug to a more polar metabolite by introducing or unmasking a functional group: oxidation, reduction, hydrolysis. Phase ii: conjugation: glucuronidation, sulfation, acetylation, methylation, others (glycine, glutathione, explain the importance of the hepatic microsomal (cytochrome p450) enzyme system in drug metabolism. In this oxidation-reduction process, two microsomal enzymes play a role: 1. Oxidized (fe+3) p450 combines with a drug substrate to form a binary complex(step 1) Nadph donates an electron to the flavoprotein p450 reductase which in turn reduces the oxidized p450-drug complex (step 2) A second electron is introduced from nadph via the same p450 reductase, which serves to reduce molecular oxygen and to form an (cid:498)activated oxygen(cid:499)- This complex in turn transfers activated oxygen to the drug substrate to form the oxidized product (step 4: explain the clinical significance of individual variation in drug metabolism.
