<unk>  of drugs.<unk>  refers to the circulation of biliary acids, bilirubin, drugs or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver.<unk>  is an especially important concept in the field of toxicology as many lipophilic xenobiotics undergo this process causing repeated liver damage.
Enterohepatic circulation
Enteroenteric circulation
Vascular permeability
Intestinal permeability
Intravasation
Extravasation 
Fresh gas flow
Vascular recruitment