R. Stack, P. Rudewicz
Jun 1, 1995
Citations
1
Influential Citations
9
Citations
Quality indicators
Journal
Journal of Mass Spectrometry
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 [14C] 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.