Generating an in vitro-in vivo correlation for metabolism and liver enrichment of a hepatitis C virus drug, faldaprevir, using a rat hepatocyte model (HepatoPac)

Drug Metab Dispos. 2014 Mar;42(3):407-14. doi: 10.1124/dmd.113.055947. Epub 2013 Dec 23.

Abstract

Hepatocytes provide an integrated model to study drug metabolism and disposition. As a result of a loss of polarity or a significant decrease in the expression of enzymes and transporters, suspended and sandwich-cultured hepatocytes have limitations in determining hepatocellular drug concentrations. Underprediction of the extent of glucuronidation is also a concern for these hepatocyte models. Faldaprevir is a hepatitis C virus protease inhibitor in late-stage development that has demonstrated significant liver enrichment in in vivo rat models based on quantitative whole-body autoradiography (QWBA) and liver-to-plasma area under-the-curve ratio. In bile duct cannulated rats, the primary biliary metabolite was a glucuronide. Owing to ethical concerns, it is difficult to assess liver enrichment in humans, and a lack of in vitro and in vivo correlation of glucuronidation has been reported. The current study was conducted to verify whether a hepatocyte model, rat HepatoPac, could overcome some of these limitations and provide validity for follow-up studies with human HepatoPac. With rat HepatoPac, liver enrichment values averaged 34-fold and were consistent with rat QWBA (26.8-fold) and in vivo data (42-fold). In contrast, liver enrichment in suspended hepatocytes was only 2.8-fold. Furthermore, the extent of faldaprevir glucuronidation in HepatoPac studies was in agreement with in vivo results, with glucuronidation as the major pathway (96%). Suspended rat hepatocytes did not generate the glucuronide or two key hydroxylated metabolites that were observed in vivo. Overall, our studies suggest that HepatoPac is a promising in vitro model to predict in vivo liver enrichment and metabolism, especially for glucuronidation, and has demonstrated superiority over suspended hepatocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoisobutyric Acids
  • Animals
  • Antiviral Agents / metabolism*
  • Antiviral Agents / pharmacokinetics
  • Bile / metabolism
  • Biological Transport
  • Biotransformation
  • Cells, Cultured
  • Coculture Techniques
  • Cryopreservation
  • Culture Media
  • Dose-Response Relationship, Drug
  • Drug Stability
  • Fibroblasts / cytology
  • Glucuronides / metabolism*
  • Hepacivirus / drug effects*
  • Hepatocytes / cytology
  • Hepatocytes / drug effects*
  • Hepatocytes / metabolism
  • Leucine / analogs & derivatives
  • Liver / metabolism*
  • Male
  • Metabolic Clearance Rate
  • Molecular Structure
  • Oligopeptides / metabolism*
  • Oligopeptides / pharmacokinetics
  • Proline / analogs & derivatives
  • Quinolines
  • Rats
  • Rats, Long-Evans
  • Rats, Sprague-Dawley
  • Thiazoles / metabolism*
  • Thiazoles / pharmacokinetics

Substances

  • Aminoisobutyric Acids
  • Antiviral Agents
  • Culture Media
  • Glucuronides
  • Oligopeptides
  • Quinolines
  • Thiazoles
  • faldaprevir
  • Proline
  • Leucine