title: Simultaneous quantitation of hydrochlorothiazide and metoprolol in human plasma by liquid chromatography-tandem mass spectrometry.
abstract: A rapid and sensitive method for the simultaneous quantitation of hydrochlorothiazide (HCT) and metoprolol (MET) in human plasma based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated. MS/MS detection involved switching the electrospray ionization (ESI) mode during chromatography from negative to detect HCT and its internal standard (I.S.) 5-bromouracil to positive to detect MET and its I.S. tramadol. Sample preparation by liquid-liquid extraction with diethyl ether-dichloromethane (60:40, v/v) was followed by chromatography on a Venusil MP-C18 column using methanol-ammonium acetate (10mM)-formic acid (pH 3.4) (50:50:0.05, v/v/v) at a flow rate of 0.8mL/min. The method was linear in the concentration range 3-1000ng/mL for both HCT and MET using 100microL human plasma. Intra- and inter-day precisions (as relative standard deviation) for HCT were 2.9-3.9% and 3.9-4.7%, respectively and for MET were 2.4-4.1% and 4.7-6.2%, respectively. Accuracies (as relative error) were +/-3.8% and +/-2.6% for HCT and MET, respectively. The assay was successfully applied to a pharmacokinetic study involving a single oral dose of a combination tablet (25mg HCT, 50mg MET) in healthy volunteers.
authors.affiliation: Research Center for Drug Metabolism, College of Life Science, Jilin University, Changchun 130021, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Mengliang
authors.initials: M
authors.lastname: Zhang
authors.forename: Xiangyong
authors.initials: X
authors.lastname: Cui
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Wang
authors.forename: Yantong
authors.initials: Y
authors.lastname: Sun
authors.forename: Jingkai
authors.initials: J
authors.lastname: Gu
mesh_terms: D000284:Administration, Oral; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D002138:Calibration; D002853:Chromatography, Liquid / Q000592:standards; D004338:Drug Combinations; D006801:Humans; D006852:Hydrochlorothiazide / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D006863:Hydrogen-Ion Concentration; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics; D015588:Observer Variation; D012015:Reference Standards; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000592:standards; D013607:Tablets; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D000959:Antihypertensive Agents; D004338:Drug Combinations; D013607:Tablets; D006852:Hydrochlorothiazide; D008790:Metoprolol