title: Pharmacokinetics of saquinavir hard gel/ritonavir (1000/100 mg twice daily) when administered with tenofovir diproxil fumarate in HIV-1-infected subjects.
abstract: OBJECTIVE
  To investigate whether the administration of tenofovir diproxil fumarate 300 mg once daily alters the plasma pharmacokinetics of the saquinavir hard gel/ritonavir combination in HIV-1 infected individuals.
  
  
  METHODS
  On day 1, 12 h pharmacokinetic profiles for saquinavir/ritonavir (1000/100 mg given twice daily) were obtained for 18 subjects. All subjects were receiving ongoing treatment with a saquinavir/ritonavir-containing regimen. Tenofovir diproxil fumarate 300 mg given once daily was then added to the regimen and blood sampling was repeated at days 3 and 14. Saquinavir and ritonavir concentrations were measured by HPLC-MS/MS, and tenofovir concentrations by HPLC with UV detection.
  
  
  RESULTS
  Following the addition of tenofovir diproxil fumarate to the regimen, saquinavir and ritonavir plasma concentrations were not significantly different compared with day 1. Thus the geometric mean ratios (95% confidence intervals) for the area under the concentration-time curve were 1.16 (0.97, 1.59) and 0.99 (0.87, 1.30) for saquinavir and 1.05 (0.92, 1.28) and 1.08 (0.97, 1.30) for ritonavir, on days 3 and 14, respectively.
  
  
  CONCLUSIONS
  Tenofovir diproxil fumarate did not alter the pharmacokinetics of saquinavir hard gel/ritonavir.
authors.affiliation: PK Research Ltd., St. Stephen's Centre, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, UK. marta.boffito@chelwest.nhs.uk
authors.forename: Marta
authors.initials: M
authors.lastname: Boffito
authors.forename: David
authors.initials: D
authors.lastname: Back
authors.forename: Meredith
authors.initials: M
authors.lastname: Stainsby-Tron
authors.forename: Andrew
authors.initials: A
authors.lastname: Hill
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Perri
authors.forename: Graeme
authors.initials: G
authors.lastname: Moyle
authors.forename: Mark
authors.initials: M
authors.lastname: Nelson
authors.forename: Jaqui
authors.initials: J
authors.lastname: Tomkins
authors.forename: Brian
authors.initials: B
authors.lastname: Gazzard
authors.forename: Anton
authors.initials: A
authors.lastname: Pozniak
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000494:pharmacology*; D019540:Area Under Curve; D004338:Drug Combinations; D004347:Drug Interactions; D005782:Gels; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics*; D015497:HIV-1; D006207:Half-Life; D006801:Humans; D008875:Middle Aged; D063065:Organophosphonates / Q000008:administration & dosage / Q000494:pharmacology*; D019438:Ritonavir / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019258:Saquinavir / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000068698:Tenofovir
chemical_list: D019380:Anti-HIV Agents; D004338:Drug Combinations; D005782:Gels; D017320:HIV Protease Inhibitors; D063065:Organophosphonates; D000068698:Tenofovir; D000225:Adenine; D019258:Saquinavir; D019438:Ritonavir