Transporters in the intestine limiting drug and toxin absorption

ABSTRACT

The pharmacokinetic behaviour of drugs strongly depends on transporters inintestine and liver. The extent of absorption in the intestine depends on diffusionacross the mucosa as well as transporter-mediated uptake across the apical membraneof enterocytes. Efflux pumps in this membrane may strongly reduce the extent of netuptake. These efflux pumps are ATP-binding cassette (ABC) transporters which arealso expressed in the apical membrane of the hepatocyte were they mediate excretioninto bile. This combined activity strongly determines whether drugs have access tothe systemic circulation (AU)