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.
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.
Li
Chuan
C
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
Ji
Zhouhua
Z
Nan
Fajun
F
Shao
Qingxiang
Q
Liu
Ping
P
Dai
Jieyu
J
Zhen
Jiang
J
Yuan
Hao
H
Xu
Fang
F
Cui
Jian
J
Huang
Bin
B
Zhang
Meiyun
M
Yu
Cheng
C
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
D018687:Antidepressive Agents, Second-Generation; D012997:Solvents; D005473:Fluoxetine; D003903:Deuterium; C036139:norfluoxetine