title: A LC-MS method to quantify tenofovir urinary concentrations in treated patients.
abstract: Tenofovir disoproxil fumarate is a prodrug of tenofovir used in the treatment of HIV and HBV infections: it is the most used antiretroviral worldwide. Tenofovir is nucleotidic HIV reverse trascriptase inhibitor that showed excellent long-term efficacy and tolerability. However renal and bone complications (proximal tubulopathy, hypophosphatemia, decreased bone mineral density, and reduced creatinine clearance) limit its use. Tenofovir renal toxicity has been suggested as the consequence of drug entrapment in proximal tubular cells: measuring tenofovir urinary concentrations may be a proxy of this event and it may be used as predictor of tenofovir side effects. No method is currently available for quantifying tenofovir in this matrix: then, the aim of this work was to validate a new LC-MS method for the quantification of urinary tenofovir. Chromatographic separation was achieved with a gradient (acetonitrile and water with formic acid 0.05%) on an Atlantis 5 μm T3, 4.6 mm × 150 mm, reversed phase analytical column. Detection of tenofovir and internal standard was achieved by electrospray ionization mass spectrometry in the positive ion mode. Calibration ranged from 391 to 100,000 ng/mL. The limit of quantification was 391 ng/mL and the limit of detection was 195 ng/mL. Mean recovery of tenofovir and internal standard were consistent and stable, while matrix effect resulted low and stable. The method was tested on 35 urine samples from HIV-positive patients treated with tenofovir-based HAARTs and did not show any significant interference with antiretrovirals or other concomitantly administered drugs. All the observed concentrations in real samples fitted the calibration range, confirming the capability of this method for the use in clinical routine. Whether confirmed in ad hoc studies this method may be used for quantifying tenofovir urinary concentrations and help managing HIV-positive patients treated with tenofovir.
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Simiele
authors.affiliation: Pharmacy Department, Amedeo di Savoia Hospital of Turin, Turin, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Carcieri
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Amedeo
authors.initials: A
authors.lastname: De Nicolò
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ariaudo
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Sciandra
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Calcagno
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonora
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Di Perri
authors.affiliation: Laboratory of Clinical Pharmacology and Pharmacogenetics, Department of Medical Sciences, University of Turin, Amedeo di Savoia Hospital, Turin 10149, Italy. Electronic address: antonio.davolio@unito.it.
authors.forename: Antonio
authors.initials: A
authors.lastname: D'Avolio
mesh_terms: D023241:Antiretroviral Therapy, Highly Active / Q000379:methods; D002138:Calibration; D002845:Chromatography; D002853:Chromatography, Liquid / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods; D015658:HIV Infections / Q000188:drug therapy; D006509:Hepatitis B / Q000188:drug therapy; D006801:Humans; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D015203:Reproducibility of Results; D000068698:Tenofovir / Q000032:analysis / Q000652:urine*; D014481:United States; D014486:United States Food and Drug Administration; D016482:Urinalysis
chemical_list: D000068698:Tenofovir
keywords: HBV; HIV; Mass spectrometry; TDF; Therapeutic drug monitoring; Urine