title: Simultaneous determination of the HIV-protease inhibitors indinavir, nelfinavir, saquinavir and ritonavir in human plasma by reversed-phase high-performance liquid chromatography.
abstract: A sensitive high-performance liquid chromatographic method has been developed for the simultaneous determination of the four licensed HIV-protease inhibitors indinavir, nelfinavir, saquinavir and ritonavir. An aliquot of 500 microl plasma, spiked with internal standard, was extracted with 0.5 ml 0.1 M NH4OH and 5 ml methyl tert.-butyl ether. After evaporating, the residue was dissolved in eluent consisting of acetonitrile-50 mM phosphate buffer, pH 5.63 (40:60, v/v). Subsequently, the eluent was washed with hexane. Chromatography was performed using a C18 reversed-phase column and gradient elution with a linear increase of acetonitrile from 36 to 66%. Ultraviolet detection at 215 nm was used. Linearity of the method was obtained in the concentration range of 45-30 000 ng/ml for all four analytes. The method was validated extensively and stability tests under various conditions were performed. The assay is now in use to analyse plasma samples from patients treated with (combinations of) HIV-protease inhibitors.
authors.affiliation: Department of Clinical Pharmacy, University Hospital Nijmegen, The Netherlands. p.hugen@klinfarm.azn.nl
authors.forename: P W
authors.initials: PW
authors.lastname: Hugen
authors.forename: C P
authors.initials: CP
authors.lastname: Verweij-van Wissen
authors.forename: D M
authors.initials: DM
authors.lastname: Burger
authors.forename: E W
authors.initials: EW
authors.lastname: Wuis
authors.forename: P P
authors.initials: PP
authors.lastname: Koopmans
authors.forename: Y A
authors.initials: YA
authors.lastname: Hekster
mesh_terms: D019380:Anti-HIV Agents / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy; D017320:HIV Protease Inhibitors / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use; D006801:Humans; D019469:Indinavir / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D019888:Nelfinavir / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D015203:Reproducibility of Results; D019438:Ritonavir / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D019258:Saquinavir / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D013056:Spectrophotometry, Ultraviolet
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D019469:Indinavir; D019888:Nelfinavir; D019258:Saquinavir; D019438:Ritonavir