title: Effect of quercetin on the plasma and intracellular concentrations of saquinavir in healthy adults.
abstract: OBJECTIVE
  To determine if quercetin, a bioflavonoid that inhibits p-glycoprotein, alters plasma saquinavir concentrations, and to explore the potential influence on intracellular concentrations.
  
  
  METHODS
  Prospective pharmacokinetic analysis.
  
  
  METHODS
  University-affiliated general clinical research center.
  
  
  METHODS
  Ten healthy adults (four women, six men) with a mean +/- SD age of 30.7 +/- 9.4 years.
  
  
  METHODS
  All subjects received saquinavir 1200 mg 3 times/day with food on days 1-11 and quercetin 500 mg 3 times/day with food on days 4-11.
  
  
  RESULTS
  On days 4 and 11, nine blood samples and four peripheral blood mononuclear cell samples were drawn during a steady-state dosing interval. Pharmacokinetic parameters were calculated by using standard noncompartmental techniques. Plasma saquinavir concentrations were similar regardless of quercetin administration. Geometric mean ratios for the area under the concentration-time curve during an 8-hour dosing interval (AUC0-8), maximum concentration in the dosing interval, and minimum concentration in the dosing interval were 0.99 (95% confidence interval [CI] 0.65-1.50), 0.99 (95% CI 0.64-1.54), and 1.06 (95% CI 0.68-1.67), respectively. Intracellular saquinavir concentrations displayed substantial intra- and intersubject variability, which limited the ability to determine the influence of quercetin coadministration (geometric mean ratio for AUC0-8 = 0.51 [95% CI 0.14-1.95], six patients).
  
  
  CONCLUSIONS
  Quercetin coadministration did not influence plasma saquinavir concentrations. Because of substantial inter- and intrasubject variability, more study is necessary to determine if saquinavir intracellular concentrations are altered by coadministration of quercetin.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, Buffalo, New York, 14642, USA. robert_dicenzo@urmc.rochester.edu
authors.forename: Robert
authors.initials: R
authors.lastname: DiCenzo
authors.forename: Valerie
authors.initials: V
authors.lastname: Frerichs
authors.forename: Panupong
authors.initials: P
authors.lastname: Larppanichpoonphol
authors.forename: Lisa
authors.initials: L
authors.lastname: Predko
authors.forename: Amy
authors.initials: A
authors.lastname: Chen
authors.forename: Richard
authors.initials: R
authors.lastname: Reichman
authors.forename: Marilyn
authors.initials: M
authors.lastname: Morris
mesh_terms: D000328:Adult; D005260:Female; D017320:HIV Protease Inhibitors / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D011794:Quercetin / Q000494:pharmacology*; D019258:Saquinavir / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D017320:HIV Protease Inhibitors; D011794:Quercetin; D019258:Saquinavir