title: Integration of preclinical and clinical data with pharmacokinetic modeling and simulation to evaluate fexofenadine as a probe for hepatobiliary transport function.
abstract: OBJECTIVE
  The suitability of fexofenadine as a probe substrate to assess hepatobiliary transport function in humans was evaluated by pharmacokinetic modeling/simulation and in vitro/in situ studies using chemical modulators.
  
  
  METHODS
  Simulations based on a pharmacokinetic model developed to describe fexofenadine disposition in humans were conducted to examine the impact of altered hepatobiliary transport on fexofenadine disposition. The effect of GF120918 on fexofenadine disposition was evaluated in human sandwich-cultured hepatocytes (SCH). Additionally, the effect of GF120918, bosentan, and taurocholate on fexofenadine disposition in perfused livers from TR(-) Wistar rats was examined.
  
  
  RESULTS
  Based on modeling/simulation, fexofenadine systemic exposure was most sensitive to changes in the hepatic uptake rate constant, and did not reflect changes in hepatic exposure due to altered hepatic efflux. GF120918 did not impair fexofenadine biliary excretion in human SCH. GF120918 coadministration significantly decreased Cl'(biliary) to 27.5% of control in perfused rat livers.
  
  
  CONCLUSIONS
  Simulations were in agreement with perfused liver data which predicted changes in fexofenadine systemic exposure primarily due to altered hepatic uptake. Fexofenadine is not a suitable probe to assess hepatic efflux function based on systemic concentrations. GF120918-sensitive protein(s) mediate fexofenadine biliary excretion in rat liver, whereas in human hepatocytes multiple efflux proteins are involved in fexofenadine hepatobiliary disposition.
authors.affiliation: Division of Pharmacotherapy and Experimental Therapeutics, Eshelman School of Pharmacy, The University of North Carolina at Chapel Hill, 311 Pharmacy Lane, C.B. #7360 Kerr Hall, Chapel Hill, North Carolina 27599-7360, USA.
authors.forename: Brandon
authors.initials: B
authors.lastname: Swift
authors.forename: Xianbin
authors.initials: X
authors.lastname: Tian
authors.forename: Kim L R
authors.initials: KL
authors.lastname: Brouwer
mesh_terms: D000818:Animals; D001659:Biliary Tract / Q000378:metabolism*; D002478:Cells, Cultured; D039563:Histamine H1 Antagonists, Non-Sedating / Q000493:pharmacokinetics*; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008954:Models, Biological; D015335:Molecular Probes; D051381:Rats; D017208:Rats, Wistar; D016593:Terfenadine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
chemical_list: D039563:Histamine H1 Antagonists, Non-Sedating; D015335:Molecular Probes; D016593:Terfenadine; C093230:fexofenadine