Analytical Sciences 2008-07-01

Characterization and quantification of fluoxymesterone metabolite in horse urine by gas chromatography/mass spectrometry.

Masayuki Yamada, Sugako Aramaki, Tomoo Hosoe, Masahiko Kurosawa, Isao Kijima-Suda, Koichi Saito, Hiroyuki Nakazawa

Index: Anal. Sci. 24(7) , 911-4, (2008)

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Abstract

Fluoxymesterone, an anabolic steroid with the 17alpha-methyl,17beta-hydroxy group, has been developed as an oral formulation for therapeutic purposes. However, it is also used illegally in racehorses to enhance racing performance. In this study, we detected 9alpha-fluoro-17,17-dimethyl-18-norandrostane-4,13-dien-11beta-ol-3-one by gas chromatography/mass spectrometry (GC/MS), which has not been reported as a fluoxymesterone metabolite so far in horse. It was synthesized for use as a reference standard, and characterized on the basis of (1)H NMR and (13)C NMR spectra, as well as GC/MS EI mass spectra of TMS derivatives. It was excreted as the main metabolite in horse urine, and its reference standard could be synthesized easily. Therefore, this metabolite could be a useful target for a doping test of fluoxymesterone in racehorses.