Final answer:
Properties of MTX that favor biliary excretion include metabolic stability, permeability across intestinal epithelial cells, and interaction with efflux transporters like P-glycoprotein (PgP).
Step-by-step explanation:
Properties of MTX that favor biliary excretion
MTX, or methotrexate, is a drug commonly used in chemotherapy to treat various types of cancer. It is important to understand the properties of MTX that favor its biliary excretion. Biliary excretion refers to the elimination of drugs or their metabolites through the bile into the gastrointestinal tract, eventually leading to their removal from the body through feces.
Several factors contribute to the biliary excretion of MTX. First, the metabolic stability of a drug plays a crucial role. In the case of MTX, the natural S,S,S configuration is more easily metabolized, which favors its biliary excretion. Second, the permeability of the drug across the intestinal epithelial cells also affects its biliary excretion. The Caco-2 cell monolayer test is often used to assess the permeability of drugs. Lastly, the interaction with efflux transporters like P-glycoprotein (PgP) can influence the biliary excretion of MTX. The efflux of a drug can be measured by the ratio of transport in the basolateral to apical direction (ba/ab ratio).