title: A new assay based on solid-phase extraction procedure with LC-MS to measure plasmatic concentrations of tenofovir and emtricitabine in HIV infected patients.
abstract: A new solid-phase extraction (SPE) method has been developed and validated on a liquid chromatography (LC) coupled with a mass spectrometer for the determination of plasma concentrations of tenofovir (TNF) and emtricitabine (FTC) in HIV infected patients. Chromatographic separation was achieved with a gradient (acetonitrile and water with formic acid 0.05%) on an Atlantis 4.6 mm x 150 mm, reversed phase analytical column. Detection of TNF, FTC, and internal standard (IS) was achieved by electrospray ionization mass spectrometry (ESI-MS) in the positive ion mode. Calibration ranged from 15.6 to 4000 ng/mL for TNF and 11.7 to 3000 ng/mL for FTC. Plasma was analyzed, and the limit of quantitation was 15.6 ng/mL for TNF and 11.7 ng/mL for FTC; limit of detection was 2 ng/mL for TNF and 1.5 ng/mL for FTC. Mean recovery of TNF, FTC, and IS were 46.5% [relative standard deviation (RSD): 8.8%] and 88.8% (RSD: 1.0%), and 81.7% (RSD: 3.1%), respectively. The method did not show any significant interference with antiretrovirals or other concomitant drugs administered to patients, and no significant "matrix effects" were observed. The method was applied for the determination of antiretroviral plasma concentration of HIV-positive patients treated with FTC and/or TNF, in combination with various other antiretrovirals.
authors.affiliation: Department of Infectious Diseases, University of Torino, Amedeo di Savoia Hospital, Corso Svizzera 164 - 10149 Turin (ITALY). antonio.davolio@unito.it
authors.forename: Antonio
authors.initials: A
authors.lastname: D'Avolio
authors.forename: Mauro
authors.initials: M
authors.lastname: Sciandra
authors.forename: Marco
authors.initials: M
authors.lastname: Siccardi
authors.forename: Lorena
authors.initials: L
authors.lastname: Baietto
authors.forename: Daniel
authors.initials: D
authors.lastname: Gonzalez de Requena
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonora
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Perri
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D019380:Anti-HIV Agents / Q000097:blood* / Q000627:therapeutic use; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D000068679:Emtricitabine; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D063065:Organophosphonates / Q000097:blood* / Q000627:therapeutic use; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D000068698:Tenofovir
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D003841:Deoxycytidine; D000068698:Tenofovir; D000068679:Emtricitabine; D000225:Adenine