title: A rapid and sensitive method for determination of dimethyl benzoylphenyl urea in human plasma by using LC/MS/MS.
abstract: Dimethyl benzoylphenyl urea (BPU), a poorly water-soluble benzoylphenyl urea derivative, inhibits tubulin polymerization and causes microtubule depolymerization in vitro with activity against solid tumors. BPU is currently being tested in Phase I clinical trials. A rapid, sensitive and specific method using LC/MS/MS has been developed for the quantitation of BPU in human plasma to perform pharmacokinetic (PK) and pharmacodynamic (PD) studies of BPU administered orally once a week. BPU is extracted from plasma into acetonitrile-n-butylchloride and separated on a Waters X-Terra MS C18 (50 x 2.1 mm, 3.5 microm) column with acetonitrile/water mobile phase (80:20, v/v) containing 0.1% formic acid using isocratic flow at 0.15 ml/min for 5 min. The analyte of interest was monitored by tandem-mass spectrometry with electrospray positive ionization with a cone voltage 15 V for BPU and 30 V for the internal standard, paclitaxel. The detector settings allowed the monitoring of the [MH](+) ion of BPU (m/z 470.3) and the [MH](+) of internal standard paclitaxel (m/z 854.5), with subsequent monitoring of the product ions of BPU (m/z 148.0) and paclitaxel (m/z 286.1). Calibration curves were generated over the range of 0.05-10 ng/ml with values for coefficient of determination of >0.99. The values for precision and accuracy were <20 and < or =15%, respectively. Following administration of BPU 5 mg as a weekly oral dose to a patient with advanced solid tumor malignancies, the maximum plasma concentration was 6.5 ng/ml and concentrations were quantifiable up to 173 h after administration. The lower limit of quantitation (LLOQ) of 0.05 ng/ml allows for successful measurement of plasma concentrations in patients receiving therapy with BPU as a once weekly oral dose.
authors: The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Bunting-Blaustein Cancer Research Bldg, Room 1M86, 1650 Orleans Street, Baltimore, MD 21231-1000, USA.
authors: Ming
authors: M
authors: Zhao
authors: Yelena
authors: Y
authors: Zabelina
authors: Michelle A
authors: MA
authors: Rudek
authors: Antonio C
authors: AC
authors: Wolff
authors: Sharyn D
authors: SD
authors: Baker
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D014508:Urea / Q000097:blood* / Q000737:chemistry; D014992:Xylenes / Q000097:blood* / Q000737:chemistry
chemical_list: D014992:Xylenes; D014508:Urea