Pharmacokinetic model of presystemic metabolism.
A pharmacokinetic perfusion model is presented that describes the disposition of drugs that are subject to both first-pass hepatic and intestinal epithelial metabolism. Equations are developed to estimate hepatic and intestinal epithelial clearances by determining drug concentrations as a function of time in both portal and peripheral vein blood after oral and iv administration, and by determining or estimating the flow rate of blood perfusing the gastrointestinal tissues. A method that can be used, under the stated conditions, to approximate the systemic availability after oral administration of drugs subject to presystemic metabolism is also developed.
Pharmacokinetic model of presystemic metabolism. A pharmacokinetic perfusion model is presented that describes the disposition of drugs that are subject to both first-pass hepatic and intestinal epithelial metabolism. Equations are developed to estimate hepatic and intestinal epithelial clearances by determining drug concentrations as a function of time in both portal and peripheral vein blood after oral and iv administration, and by determining or estimating the flow rate of blood perfusing the gastrointestinal tissues. A method that can be used, under the stated conditions, to approximate the systemic availability after oral administration of drugs subject to presystemic metabolism is also developed.