Quantitative determination of the anti-tumor agent tasquinimod in human urine by liquid chromatography–tandem mass spectrometry

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 961; no. May 14; pp. 42 - 48
• Main Authors: van de Merbel, Nico C., Walland, Peter, Tiensuu, Mikael, Sennbro, Carl J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.06.2014
• Subjects: Antineoplastic Agents - urine; Arbetsmedicin och miljömedicin; Chromatography; Chromatography, Liquid - methods; Drugs; Environmental Health and Occupational Health; Female; Health Sciences; Human; Humans; Hälsovetenskap; Incurred sample stability; LC–MS/MS; Liquid chromatography; Liquid-Liquid Extraction; Male; Medical and Health Sciences; Medicin och hälsovetenskap; Metabolites; Parents; Prostate cancer; Prostatic Neoplasms; Quinolines - urine; Quinolones; Reproducibility of Results; Sampling; Sensitivity and Specificity; Tandem Mass Spectrometry - methods; Tasquinimod; Urine; Urine analysis; Prostate cancer; LC–MS/MS; Incurred sample stability; Tasquinimod; Urine analysis
• ISSN: 1570-0232; 1873-376X; 1873-376X
• DOI: 10.1016/j.jchromb.2014.05.007

•An LC–MS/MS method was developed and validated for the quantitation of the oncolytic drug tasquinimod in human urine.•The LLOQ of 0.100nM (40pg/mL) is 10-fold lower than previously reported for this compound in plasma.•Extraction with n-chlorobutane selectively removes endogenous urine compounds that interfere with the ionization process.•Urinary metabolites of tasquinimod can be back-converted to parent drug at 37°C and at all relevant urine pH values (4.5–8.5).•The method was used to determine the urinary excretion of tasquinimod in healthy volunteers and renally impaired patients. Tasquinimod is an anti-tumor drug that is currently in clinical development for the treatment of solid cancers. After oral administration, tasquinimod and a number of its metabolites are excreted in the urine. The quantitative determination of tasquinimod in urine is challenging because of the required sensitivity (down to 0.1nM or 40pg/mL), the highly variable nature of this biological matrix and the presence of potentially unstable metabolites, which may convert back to the parent drug. In this article, an LC–MS/MS method is described for the determination of tasquinimod in human urine in the concentration range 0.1–200nM. Liquid–liquid extraction with n-chlorobutane was used to extract tasquinimod from 100μL human urine and to remove interfering endogenous urinary constituents. Reversed-phase liquid chromatography coupled to a triple quadrupole mass spectrometer equipped with an ESI source was used for quantification of tasquinimod in a 2.5-min run. A stable-isotope labeled internal standard was used for response normalization. The intra- and inter-day coefficients of variation (precision) as well as the bias (accuracy) of the method were below 7%. Although considerable conversion of conjugated tasquinimod metabolites back to parent drug was observed when incurred samples were stored at 37°C for a prolonged time, tasquinimod as well as its metabolites were sufficiently stable under all relevant sampling, storage and analysis conditions. The method was successfully applied to determine the urinary excretion of tasquinimod in healthy volunteers and patients with renal impairment after a 0.5-mg oral dose.