RT Journal Article
SR Electronic
T1 Analysis of phase I and phase II metabolites of tamoxifen in breast cancer patients.
JF Drug Metabolism and Disposition
JO Drug Metab Dispos
FD American Society for Pharmacology and Experimental Therapeutics
SP 1119
OP 1124
VO 21
IS 6
A1 Poon, G K
A1 Chui, Y C
A1 McCague, R
A1 Lłnning, P E
A1 Feng, R
A1 Rowlands, M G
A1 Jarman, M
YR 1993
UL http://dmd.aspetjournals.org/content/21/6/1119.abstract
AB This study describes the application of LC/MS/MS to the determination of phase I and phase II metabolites of tamoxifen in urine and plasma samples of breast cancer patients. In the plasma extracts, in addition to the parent drug and N-desmethyltamoxifen, a minor metabolite tamoxifen N-oxide was identified for the first time in human. Four intact glucuronides of tamoxifen metabolites were isolated in the 24-hr posttreatment urine sample. They were the glucuronides of 4-hydroxytamoxifen, 4-hydroxy-N-desmethyltamoxifen, dihydroxytamoxifen, and a monohydroxy-N-desmethyltamoxifen. Hydroxylation followed by glucuronidation is a well-established metabolic route of tamoxifen, and this study describes for the first time direct analyses of these metabolites in human urine samples using on-line LC tandem MS.