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Comparison of thermospray and electrospray for the analysis of the conjugates of androgen receptor antagonist zanoterone
Author(s) -
Stack Robert F.,
Rudewicz Patrick J.
Publication year - 1995
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1190300611
Subject(s) - chemistry , thermospray , chromatography , glucuronide , metabolite , mass spectrometry , electrospray , high performance liquid chromatography , electrospray ionization , tandem mass spectrometry , biotransformation , conjugate , selected reaction monitoring , biochemistry , enzyme , mathematical analysis , mathematics
Abstract The use of both pneumatically‐assisted ionspray (IS) and thermospray (TS) in liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the determination of the biotransformation pathways of zanoterone in humans is described. After administration of a single oral dose of [ 14 C] zanoterone, 16% of the dose was excreted as four metabolites in urine. Initially TS LC‐MS/MS analysis indicated the presence of monohydroxylated metabolites; however, their high‐performance liquid chromatographic (HPLC) retention times indicated more polar structures. These conflicting results led to IS experiments, in which abundant molecular ions were obtained for all four metabolites, identifying them as either glucuronide or sulfate conjugates. A contour plot of the data from an IS neutral loss experiment revealed the presence of a minor metabolite not observed in either HPLC–flow scintillation or TS LC‐MS experiments. These data demonstrate the advantages of IS LC‐MS/MS for the analysis of drug conjugates.