First-Pass Metabolism

The effect of the first liver passage For a perorally administered pharmaceutical agent to exert its effects at the site of action, it usually must enter the systemic circulation. To do so, it must pass through the intestinal wall, the liver, and part of the circulatory system. Despite complete absorption in the intestine, the bioavailability … First-Pass Metabolism

Cytochrome P450 (CYP)

CYP450 Cytochromes P450s are a family of enzymes that are of paramount importance in drug biotransformation. The most important isoenzymes for drug metabolism are: CYP1A1, CYP1A2 CYP2B6 CYP2C9, CYP2C19 CYP2D6 CYP2E1 CYP3A4, CYP3A5 and CYP3A7 The number after the abbreviation CYP stands for the family, the following letter for the subfamily and the last number … Cytochrome P450 (CYP)

Glucuronidation

Definition Glucuronidation refers to an intracellular metabolic reaction in which an endogenous or exogenous substrate is conjugated to glucuronic acid. The organism thereby makes the substrates more water soluble so that they can be rapidly excreted in the urine. Glucuronidation belongs to phase II metabolism (conjugations). UDP: uridine diphosphate UGT: UDP-glucuronosyltransferase Enzymes involved Glucuronidation is … Glucuronidation

Prodrugs

What are prodrugs? Not all active pharmaceutical ingredients are directly active. Some must first be converted to the active substance by an enzymatic or non-enzymatic conversion step in the body. These are the so-called . The term was introduced by Adrien Albert in 1958. It is estimated that up to 10% of all active ingredients … Prodrugs