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

This research focuses on the identification and quantification of fluoxymesterone, an anabolic steroid used in horse racing, by using gas chromatography/mass spectrometry. This process revealed a previously unreported metabolite of fluoxymesterone in horse urine, which could potentially be used for doping tests in the future.

Understanding Fluoxymesterone and its Usage

• Fluoxymesterone, an anabolic steroid characterized by its 17alpha-methyl,17beta-hydroxy group, is developed as a therapeutic oral formulation. Despite being used for medical purposes, it is illegally used to enhance performance in horse racing. Detecting this steroid in horses is a challenge, particularly as there is a lack of thorough understanding regarding its metabolites.

Discovery a New Metabolite

• In this study, by employing gas chromatography/mass spectrometry (GC/MS), the researchers discovered a new metabolite of fluoxymesterone named 9alpha-fluoro-17,17-dimethyl-18-norandrostane-4,13-dien-11beta-ol-3-one in horse urine. This points towards the production and excretion of this specific metabolite when Fluoxymesterone is ingested.

Synthesis of Reference Standard

• The researchers synthetized this newly-discovered metabolite to create a reference standard. This standard was characterized with (1)H Nuclear Magnetic Resonance ((1)H NMR) and (13)C Nuclear Magnetic Resonance ((13)C NMR) spectra, as well as GC/MS EI mass spectra of TMS derivatives.

The Metabolite as the Main Excretion

• This metabolite becomes the main substance excreted in horse’s urine. The process to synthesize its reference standard is fairly easy, making it a viable candidate for potential employment in future anti-doping tests.

Implications for Doping Tests

• Considering these findings, further studies could be conducted to investigate this metabolite as a potential target for fluoxymesterone doping tests in competitive horse racing. As abuse of anabolic steroids is a consistent issue in the sport, the development of new detection methods is crucial to level the playing field and promote animal welfare.