Development and validation of a liquid chromatography-mass spectrometry assay for quantification of Z- and E- isomers of endoxifen and its metabolites in plasma from women with estrogen receptor positive breast cancer.

ABSTRACT: The selective estrogen receptor modifier tamoxifen (TAM) is widely used for the treatment of women with estrogen receptor positive (ER+ ) breast cancer. Endoxifen (ENDX) is a potent, active metabolite of TAM and is important for TAM's clinical activity. While multiple papers have been published regarding TAM metabolism, few studies have examined or quantified the metabolism of ENDX. To quantify ENDX and its metabolites in patient plasma samples, we have developed and validated a rapid, sensitive, and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitative determination of the E- and Z-isomers of ENDX (0.5-500 ng/ml) and the ENDX metabolites norendoxifen (1-500 and 0.5-500 ng/ml E and Z, respectfully), ENDX catechol (3.075-307.5 and 1.92-192 ng/ml E an

SUBMITTER: Buhrow SA 

PROVIDER: S-EPMC10249430 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature