title: A simple and reliable method for determining plasma concentration of dehydroxymethylepoxyquinomicin by high performance liquid chromatography with mass spectrometry.
abstract: We have developed a simple and reliable method for determining plasma concentration of dehydroxymethylepoxyquinomicin (DHMEQ), a new low molecular weight NF-kappaB inhibitor, using high performance liquid chromatography with mass spectrometry (LC-MS). An experiment of mass spectrometry with electrospray ionization in the negative ionization mode was performed to detect ion transitions at m/z 260.05 [M-H](-) for DHMEQ and 240.29 for mefenamic acid as an internal standard. The samples were purified using liquid-liquid extraction with ethyl acetate. The method yielded a standard curve which was linear for the concentration range of 0.1-125 ng/mL when 0.05 mL plasma was used. The correlation coefficients of all standard curves were greater than or equal to 0.999. The limit of detection was 50 pg/mL (signal/noise >3). Daily fluctuation of plasma standard curve was small. The intra- and inter-assay precision ranged from 2.84 to 4.76% (n=6) and 2.91 to 7.03% (n=6), respectively. The LC-MS technique described provides a simple and reliable liquid chromatographic method for the determination of DHMEQ level and for use in studies involving pharmacokinetics.
authors.affiliation: Department of Medication Use Analysis and Clinical Research, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Watanabe
authors.forename: Nobuo
authors.initials: N
authors.lastname: Mochizuki
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Ajima
authors.forename: Keiko
authors.initials: K
authors.lastname: Ohno
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Shiino
authors.forename: Kazuo
authors.initials: K
authors.lastname: Umezawa
authors.forename: Moto
authors.initials: M
authors.lastname: Fukai
authors.forename: Michitaka
authors.initials: M
authors.lastname: Ozaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Furukawa
authors.forename: Satoru
authors.initials: S
authors.lastname: Todo
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kishino
mesh_terms: D000818:Animals; D001549:Benzamides / Q000097:blood*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003512:Cyclohexanones / Q000097:blood*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001549:Benzamides; D003512:Cyclohexanones; C464444:dehydroxymethylepoxyquinomicin