title: LC-MS/MS method for simultaneous determination of valproic acid and major metabolites in human plasma.
abstract: A rapid and sensitive method using liquid chromatography-tandem mass spectroscopy (LC-MS/MS) was developed and validated for simultaneous quantitative determination of valproic acid and three major metabolites (3-OH-valproic acid, 4-ene-valproic acid and 5-OH-valproic acid) in human plasma. The analytes and internal standard were isolated from 200 μL samples by solid phase extraction using a ZORBAX SB-C₈ column (3.5 μm, 2.1×100 mm) with an isocratic mobile phase consisting of methanol-10mM ammonium acetate (80:20, v/v) containing 0.1% formic acid at a flow rate of 0.3 mL/min. The method had a chromatographic total run time of 2.0 min. The lower limit of quantification of valproic acid, 3-OH-valproic acid, 4-ene-valproic acid and 5-OH-valproic acid of the method was 2030, 51.5, 50.15 and 51.25 ng/mL, respectively. The method was linear for valproic acid and the three metabolites with correlation coefficients >0.995 for all analytes. The intra-day and inter-day accuracy and precision of the assay were less than 15.0%. This analytical method was successfully used to assay plasma concentrations of valproic acid and the three metabolites in human plasma from epileptic patients.
authors.affiliation: Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, PR China.
authors.forename: Shouhong
authors.initials: S
authors.lastname: Gao
authors.forename: Haijun
authors.initials: H
authors.lastname: Miao
authors.forename: Xia
authors.initials: X
authors.lastname: Tao
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
authors.forename: Fei
authors.initials: F
authors.lastname: Cai
authors.forename: Yunlei
authors.initials: Y
authors.lastname: Yun
authors.forename: Jingxian
authors.initials: J
authors.lastname: Li
authors.forename: Wansheng
authors.initials: W
authors.lastname: Chen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000927:Anticonvulsants / Q000097:blood / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D000432:Methanol / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014635:Valproic Acid / Q000097:blood* / Q000378:metabolism
chemical_list: D000927:Anticonvulsants; D014635:Valproic Acid; D000432:Methanol