title: Simultaneous quantification of oxysophocarpine and its active metabolite sophocarpine in rat plasma by liquid chromatography/mass spectrometry for a pharmacokinetic study.
abstract: A sensitive, rapid and specific method for the simultaneous quantification of oxysophocarpine (OSC) and its active metabolite sophocarpine (SC) in rat plasma was developed and validated, using a liquid-liquid extraction procedure followed by liquid chromatography/electrospray ionization mass spectrometric (LC/ESI-MS) analysis. The separation was performed on a Zorbax Extend-C(18) column (2.1 mm i.d. x 50 mm, 5 microm) with a C(18) guard column using methanol-water containing 5 mm ammonium acetate (15:85, v/v) as mobile phase. Analysis was performed in selected ion monitoring (SIM) mode with an electrospray ionization (ESI) interface. [M + H](+) at m/z 263 for OSC, [M + H](+) at m/z 247 for SC and [M + H](+) at m/z 249 for matrine (internal standard) were selected as detecting ions, respectively. The method was linear in the concentration ranges 10-1000 ng/mL for OSC and 5-500 ng/mL for SC. The intra- and inter-day precisions (coefficient of variation) were within 7% for both analytes. Their accuracy (relative error) ranged from -6.4 to 1.5%. The limits of detection for OSC and SC were 3 and 1.5 ng/mL, respectively. The limits of quantitation for OSC and SC were 10 and 5 ng/mL, respectively. Recoveries of both analytes were greater than 85% at the low, medium and high concentrations. Both analytes were stable during all sample storage, preparation and analytic procedures. The method was successfully applied to a pharmacokinetic study after an oral administration of OSC to rats with a dose of 15 mg/kg.
authors.affiliation: Key Laboratory of Drug Metabolism and Pharmacokinetics, Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850, People's Republic of China.
authors.forename: Su-Jun
authors.initials: SJ
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Xiao-Tian
authors.initials: XT
authors.lastname: Li
authors.forename: Guang-Ji
authors.initials: GJ
authors.lastname: Wang
mesh_terms: D000470:Alkaloids / Q000097:blood* / Q000493:pharmacokinetics; D000818:Animals; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D000093842:Matrines
chemical_list: D000470:Alkaloids; C035933:sophocarpine; D000093842:Matrines