title: Liquid chromatography/tandem mass spectrometry for the determination of fluoxetine and its main active metabolite norfluoxetine in human plasma with deuterated fluoxetine as internal standard.
abstract: Fluoxetine (F) and its N-demehylated metabolite norfluoxetine (NF) are selective inhibitors of serotonin reuptake in humans. A new sensitive rapid method for the simultaneous determination of F and NF in plasma was established and validated, and was further applied to assess the bioequivalence of two oral formulations of F in 22 healthy Chinese male volunteers who received a single oral dose of each formulation (containing 20 mg of fluoxetine hydrochloride). The new method involves using liquid chromatography/tandem mass spectrometry (LC/MS/MS) in multiple reaction monitoring mode with deuterated fluoxetine (DF) as internal standard. High levels of analytical sensitivity and specificity of MS/MS detection enabled use of a simple liquid-liquid extraction procedure. The combination of a simple sample clean-up procedure and short chromatographic run-time (5 min) considerably increased the productivity of the analytical method. The method was validated for the plasma concentration range 0.27-22 ng/mL for both of the test compounds, and the calibration curves were linear with coefficients of correlation >0.999. The limit of detection was 0.1 ng/mL for plasma F and NF. Taking the plasma sample size (200 micro L) into account the new method for determination of F and NF is more sensitive than those described previously.
authors.affiliation: Shanghai Institute of Materia Medica, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 294 Taiyuan Road, Shanghai 200031, China. chli@mail.shcnc.ac.cn
authors.forename: Chuan
authors.initials: C
authors.lastname: Li
authors.forename: Zhouhua
authors.initials: Z
authors.lastname: Ji
authors.forename: Fajun
authors.initials: F
authors.lastname: Nan
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Shao
authors.forename: Ping
authors.initials: P
authors.lastname: Liu
authors.forename: Jieyu
authors.initials: J
authors.lastname: Dai
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhen
authors.forename: Hao
authors.initials: H
authors.lastname: Yuan
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.forename: Bin
authors.initials: B
authors.lastname: Huang
authors.forename: Meiyun
authors.initials: M
authors.lastname: Zhang
authors.forename: Cheng
authors.initials: C
authors.lastname: Yu
mesh_terms: D000328:Adult; D018687:Antidepressive Agents, Second-Generation / Q000097:blood*; D019540:Area Under Curve; D002138:Calibration; D002853:Chromatography, Liquid; D003903:Deuterium; D005473:Fluoxetine / Q000031:analogs & derivatives* / Q000097:blood* / Q000493:pharmacokinetics; D006207:Half-Life; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012997:Solvents
chemical_list: D018687:Antidepressive Agents, Second-Generation; D012997:Solvents; D005473:Fluoxetine; D003903:Deuterium; C036139:norfluoxetine