Analysis of tamoxifen and its metabolites in synthetic gastric fluid digests and urine samples using high-performance liquid chromatography with electrospray mass spectrometry.
We report on the transformation of tamoxifen at 37 degrees C in synthetic gastric fluid as studied by high-performance liquid chromatography with triple quadrupole mass spectrometry. The major transformation products detected were (E)-isomer of tamoxifen, metabolite D, and several unidentified components having m/z 404. Addition of pepsin to the gastric fluid inhibited formation of all of these products. We analyzed several urine samples from breast cancer patients undergoing tamoxifen treatment. Metabolite D was identified in the urine samples and in the gastric fluid digest at a retention time of 22.0 min eluting from a reversed-phase HPLC column. Although several metabolites were found in all the urine samples of patients, some metabolites were detected in one sample but not others, suggesting tamoxifen metabolism varies in patients.
Li
X F
XF
University of Alberta, Edmonton, Canada.
Carter
S
S
Dovichi
N J
NJ
Zhao
J Y
JY
Kovarik
P
P
Sakuma
T
T
D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000652:urine; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D020847:Estrogen Receptor Modulators / Q000378:metabolism* / Q000627:therapeutic use / Q000652:urine; D005750:Gastric Juice / Q000378:metabolism*; D006801:Humans; D021241:Spectrometry, Mass, Electrospray Ionization; D013629:Tamoxifen / Q000378:metabolism* / Q000627:therapeutic use / Q000652:urine
D020847:Estrogen Receptor Modulators; D013629:Tamoxifen