title: Highly sensitive determination of saquinavir in biological samples using liquid chromatography-tandem mass spectrometry.
abstract: A selective and sensitive method for the determination of the HIV protease inhibitor saquinavir in human plasma, saliva, and urine using liquid-liquid extraction and LC-MS-MS has been developed, validated, and applied to samples of a healthy individual. After extraction with ethyl acetate, sample extracts were chromatographed isocratically within 5 min on Kromasil RP-18. The drug was detected with tandem mass spectrometry in the selected reaction monitoring mode using an electrospray ion source and 2H(5)-saquinavir as internal standard. The limit of quantification was 0.05 ng/mL. The accuracy of the method varied between -1 and +10% (SD within-batch) and the precision ranged from +4 to +10% (SD batch-to-batch). The method is linear at least within 0.05 and 87.6 ng/mL. After a regular oral dose (600 mg) saquinavir concentrations were detectable for 48 h in plasma and were well correlated with saliva concentrations (r(2)=0.9348, mean saliva/plasma ratio 1:15.1). The method is well suited for low saquinavir concentrations in different matrices.
authors.affiliation: Department of Internal Medicine VI, Bergheimer Strasse 58, University of Heidelberg, D-69115, Heidelberg, Germany. juergen_burhenne@med.uni-heidelberg.de
authors.forename: Jürgen
authors.initials: J
authors.lastname: Burhenne
authors.forename: Klaus Dieter
authors.initials: KD
authors.lastname: Riedel
authors.forename: Meret
authors.initials: M
authors.lastname: Martin-Facklam
authors.forename: Gerd
authors.initials: G
authors.lastname: Mikus
authors.forename: Walter E
authors.initials: WE
authors.lastname: Haefeli
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D017320:HIV Protease Inhibitors / Q000032:analysis* / Q000097:blood / Q000652:urine; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D012015:Reference Standards; D012463:Saliva / Q000737:chemistry; D019258:Saquinavir / Q000032:analysis* / Q000097:blood / Q000652:urine; D012680:Sensitivity and Specificity
chemical_list: D017320:HIV Protease Inhibitors; D019258:Saquinavir