title: Simultaneous determination of flupirtine and its major active metabolite in human plasma by liquid chromatography-tandem mass spectrometry.
abstract: A rapid, selective and sensitive HPLC-tandem mass spectrometry method was developed and validated for simultaneous determination of flupirtine and its active metabolite D-13223 in human plasma. The analytes and internal standard diphenhydramine were extracted from plasma samples by liquid-liquid extraction, and chromatographed on a C18 column. The mobile phase consisted of acetonitrile-water-formic acid (60:40:1, v/v/v), at a flow rate of 0.5 ml/min. Detection was performed on a triple quadrupole tandem mass spectrometer by selected reaction monitoring (SRM) mode via atmospheric pressure chemical ionization (APCI). The method has a limit of quantitation of 10 ng/ml for flupirtine and 2 ng/ml for D-13223, using 0.5-ml plasma sample. The linear calibration curves were obtained in the concentration range of 10.0-1500.0 ng/ml for flupirtine and 2.0-300.0 ng/ml for D-13223. The intra- and inter-run precision (RSD), calculated from quality control (QC) samples was less than 7.2% for flupirtine and D-13223. The accuracy as determined from QC samples was less than 5% for the analytes. The overall extraction recoveries of flupirtine and D-13223 were determined to be about 66% and 78% on average, respectively. The method was applied for the evaluation of the pharmacokinetics of flupirtine and active metabolite D-13223 in volunteers following peroral administration.
authors.affiliation: Laboratory of Drug Metabolism and Pharmacokinetics, Shenyang Pharmaceutical University, China.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: D
authors.initials: D
authors.lastname: Zhong
authors.forename: H
authors.initials: H
authors.lastname: Xu
authors.forename: B
authors.initials: B
authors.lastname: Schug
authors.forename: H
authors.initials: H
authors.lastname: Blume
mesh_terms: D000631:Aminopyridines / Q000097:blood* / Q000378:metabolism / Q000493:pharmacokinetics; D000700:Analgesics / Q000032:analysis*; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods* / Q000592:standards; D004155:Diphenhydramine / Q000592:standards; D006801:Humans; D013058:Mass Spectrometry; D015203:Reproducibility of Results
chemical_list: D000631:Aminopyridines; D000700:Analgesics; D004155:Diphenhydramine; C034161:flupirtine