Determination of tamoxifen and its active metabolite Endoxifen in human plasma by UPLC-MS/MS and its application
Objective To establish a rapid and convenient UPLC-MS/MS method for the determination of tamoxifen and its active metabolite endoxifen in plasma of patients with breast cancer.Methods With diazepam as the internal standard,the plasma sample was precipitated with acetonitrile and methanol-acetonitrile was used as mobile phase.The samples were separated by chromatographic column ZORBAX Eclipse plus C18(18 μm,2.1 mm x50 mm)and scanned by electrospray ion source and positive ion multiple reaction monitoring mode.The ion channels were detected as tamoxifen m/z 372.0→72.1,endoxifen m/z 374.0→58.2 and diazepam m/z 285→192.9.Results The linearity of tamoxifen and endoxifen were good in the concentration range of 1-500 ng·mL-1(R2=0.999 5)and 0.5-250 ng·mL-1,respectively(R2=0.999 9).The intra-day and inter-day precision of low,medium and high quality control concentrations were all less than 10%.Tamoxifen and endoxifen were stable at low temperature and stable after repeated freeze-thaw.Conclusion The experimental results show that the method meets the requirements of biological sample analysis,and the sample treatment is simple,specific,and can be used for the accurate and rapid determination of tamoxifen and indoloxifen in human plasma.