title: Determination of metolazone in human blood by liquid chromatography with electrospray ionization tandem mass spectrometry.
abstract: A rapid, sensitive and accurate liquid chromatographic-tandem mass spectrometric method is described for the determination of metolazone in human blood. Metolazone was extracted from blood using ethyl acetate and separated on a C18 column interfaced with a triple quadrupole tandem mass spectrometer. The mobile phase consisting of a mixture of acetonitrile, 10 mmol/l ammonium acetate and formic acid (60:40:0.1, v/v/v) was delivered at a flow rate of 0.5 ml/min. Electrospray ionization (ESI) source was operated in positive ion mode. Selected reaction monitoring (SRM) mode using the transitions of m/z 366-->m/z 259 and m/z 321-->m/z 275 were used to quantify metolazone and the lorazepam (internal standard), respectively. The linearity was obtained over the concentration range of 0.5-500 ng/ml for metolazone and the lower limit of quantitation (LLOQ) was 0.5 ng/ml. For each level of QC samples, inter- and intra-run precision was less than 8.07 and 3.56% (relative standard deviation (RSD)), respectively, and the bias was within +/-4.0%. This method was successfully applied to the pharmacokinetic study of metolazone formulation after oral administration to humans.
authors.affiliation: Tianjin Key Laboratory of Pharmacokinetics and Pharmacodynamics, Tianjin Institute of Pharmaceutical Research, Tianjin 300193, PR China. weig1510@163.com
authors.forename: Guangli
authors.initials: G
authors.lastname: Wei
authors.forename: Shuhua
authors.initials: S
authors.lastname: Xiao
authors.forename: Changxiao
authors.initials: C
authors.lastname: Liu
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D008788:Metolazone / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D008788:Metolazone