Population Pharmacokinetic Modeling of the Enterohepatic Recirculation of Fimasartan in Rats, Dogs, and Humans

AAPS J. 2015 Sep;17(5):1210-23. doi: 10.1208/s12248-015-9764-2. Epub 2015 May 20.

Abstract

Enterohepatic recirculation (EHC) can greatly enhance plasma drug exposures and therapeutic effects. This study aimed to develop a population pharmacokinetic model that can simultaneously characterize the extent and time-course of EHC in three species using fimasartan, a novel angiotensin II receptor blocker, as a model drug. All fimasartan plasma concentration profiles in 32 rats (intravenous doses, 0.3-3 mg/kg; oral doses, 1-10 mg/kg), 34 dogs (intravenous doses, 0.3-1 mg/kg; oral doses, 1-10 mg/kg), and 42 healthy volunteers (single or multiple oral doses, 20-480 mg) were determined via liquid chromatography-tandem mass spectrometry (LC-MS/MS) and simultaneously modeled in S-ADAPT. The proposed model quantitatively characterized EHC in three species after oral and intravenous dosing. The median (range) fraction of drug undergoing recirculation was 76.3% (64.9-88.7%) in rats, 33.3% (24.0-45.9%) in dogs, and 65.6% (56.5-72.0%) in humans. In the presence compared with the absence of EHC, the area under the curve in plasma was predicted to be 4.22-fold (2.85-8.85) as high in rats, 1.50-fold (1.32-1.85) in dogs, and 2.91-fold (2.30-3.57) in humans. The modeled oral bioavailability in rats (median (range), 38.7% (20.0-59.8%)) and dogs (median, 7.13% to 15.4%, depending on the formulation) matched the non-compartmental estimates well. In humans, the predicted oral bioavailability was 25.1% (15.1-43.9%) under fasting and 18.2% (12.2-31.0%) under fed conditions. The allometrically scaled area under the curve predicted from rats was 420 ng·h/mL for 60 mg fimasartan compared with 424 ± 63 ng·h/mL observed in humans. The developed population pharmacokinetic model can be utilized to characterize the impact of EHC on plasma drug exposure in animals and humans.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Administration, Intravenous
  • Administration, Oral
  • Angiotensin Receptor Antagonists / administration & dosage
  • Angiotensin Receptor Antagonists / pharmacokinetics
  • Animals
  • Area Under Curve
  • Biphenyl Compounds / administration & dosage
  • Biphenyl Compounds / pharmacokinetics*
  • Chromatography, Liquid
  • Dogs
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Enterohepatic Circulation*
  • Female
  • Humans
  • Male
  • Models, Biological*
  • Pyrimidines / administration & dosage
  • Pyrimidines / pharmacokinetics*
  • Rats
  • Rats, Sprague-Dawley
  • Species Specificity
  • Tandem Mass Spectrometry
  • Tetrazoles / administration & dosage
  • Tetrazoles / pharmacokinetics*

Substances

  • Angiotensin Receptor Antagonists
  • Biphenyl Compounds
  • Pyrimidines
  • Tetrazoles
  • fimasartan