PHAR 230 Lecture Notes - Lecture 4: Cytochrome P450, Aldehyde Dehydrogenase, Portal Vein
21 Feb 2017
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Define biotransformation and describe the different types of reactions that contribute to it. Aka biotransformation: enzyme-catalyzed conversion of drugs to their metabolites. Often results in deactivation of the drug (detoxification) Liver is primary site: high conc of enzymes and high blood flow. Lung, intestine, kidney also has significant conc of enzymes (skin and gonads to lesser extent) Explain first-pass metabolism and how it relates to drug biotransformation and bioavailability. Reduction of internal concentration of a drug prior to reaching systemic circulation. Oral drugs pass directly to the liver: oral drug gets absorbed across epithelial membranes from small intestine into portal vein, portal veins transports drug directly into the liver. Iv has 100% bioavailability reduced bioavailability for oral drugs. Describe the sequence of different reactions that can occur with regards to drug metabolism, using specific examples. Phase i: unmasking of functional group create or unmask a chemical group (polar group) that allow for phase ii biotransformation.
