TY - JOUR T1 - A pharmacokinetic model for enterohepatic recirculation in the rat: phenolphthalein, a model drug. JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 100 LP - 102 VL - 7 IS - 2 AU - W A Colburn AU - P C Hirom AU - R J Parker AU - P Milburn Y1 - 1979/03/01 UR - http://dmd.aspetjournals.org/content/7/2/100.abstract N2 - A classical compartmental pharmacokinetic model was developed to describe the systemic blood concentration-time profile of phenolphthalein and its glucuronide conjugate (total 3H) following a single intravenous bolus injection of [3H]phenolphthalein. The model incorporates a biliary transport system, including a finite lag time for the biliary phenophthalein glucuronide to be hydrolyzed in the intestine before absorption. Data obtained from bile duct-cannulated animals were fit to the same model excluding any component for intestinal absorption. Agreement between the rate constants obtained for both fits indicates that the model is internally consistent. The model was then used to simulate a 24-hour time-course of phenolphthalein-equivalent blood concentrations which indicates that the long apparent half-lives calculated during this period are artifacts of recirculation. ER -