RESUMEN
Δ6-Methyltestosterone was reported as the main active ingredient of the purported "dietary supplement" Jungle Warfare. This compound is structurally similar to 17α-methyltestosterone, containing an additional Δ6 double bond, and is reported to possess notable androgenic activity, raising concerns over the potential for abuse of Jungle Warfare in sport. The in vivo metabolism of Δ6-methyltestosterone in greyhounds was investigated. Urinary phase I (unconjugated) and phase II (glucuronide) metabolites were detected following oral administration using liquid chromatography-mass spectrometry. No phase II sulfate metabolites were detected. The major phase I metabolite was confirmed as 16α,17ß-dihydroxy-17α-methylandrosta-4,6-dien-3-one by comparison with a synthetically-derived reference material. Minor amounts of the parent drug were also confirmed. Glucuronide conjugated metabolites were also observed, but were found to be resistant to hydrolysis using the Escherichia coli ß-glucuronidase enzyme. Qualitative excretion profiles, limits of detection, and extraction recoveries were determined for the parent drug and the major phase I metabolite. These results provide a method for the detection of Jungle Warfare abuse in greyhounds suitable for incorporation into routine screening methods conducted by anti-doping laboratories.
Asunto(s)
Anabolizantes , Doping en los Deportes , Animales , Perros , Metiltestosterona/análisis , Metiltestosterona/metabolismo , Cromatografía de Gases y Espectrometría de Masas/métodos , Glucurónidos , Andrógenos , Espectrometría de Masas , Anabolizantes/metabolismo , Detección de Abuso de Sustancias/métodosRESUMEN
Pre-race dosing of horses with alkalinising agents to manipulate performance has been evident in racing worldwide for over 30 years. To regulate the use of alkalinising agents, racing authorities adopted thresholds for total plasma carbon dioxide (TCO2 ) in racehorses. Traditionally, racing laboratories have measured plasma TCO2 using ion selective electrode (ISE) technology, with the Association of Official Racing Chemists (AORC) approving the use of only three ISE instruments for measurement. Because of the manufacture and support of these instruments ceasing, racing laboratories have explored alternative techniques to measure plasma TCO2 . In this study, headspace gas chromatography mass spectrometry (HSGCMS) with fully automated sample preparation was investigated as an alternative technique to ISE. Sample preparation was carried out online on a Gerstel robot, where plasma was aspirated directly from sealed vacutainer tubes before further treatment and headspace injection into a GCMS. The method was successfully cross validated against a Beckman Unicel DxC®600, meeting all criteria stipulated in the AORC cross-validation protocol. The method achieved an accuracy of 99.8%, within-run relative standard deviation of 0.22% and interday reproducibility of 0.04 mM, all significant improvements on the authors ISE method. A population study was also conducted to ensure the plasma TCO2 threshold, established with ISE methodology, did not change with the developed HSGCMS method. The concentrations and standard deviations for the two methods were almost identical, HSGCMS mean 30.62 mM, standard deviation 1.65 mM, and ISE 30.65 and 1.55 mM. The results indicate that the fully automated HSGCMS method is suitable for measurement of equine plasma TCO2 for regulatory purposes.
Asunto(s)
Dióxido de Carbono , Plasma , Animales , Cromatografía de Gases y Espectrometría de Masas , Caballos , Reproducibilidad de los ResultadosRESUMEN
Samples of the 'dietary supplement' Furazadrol sourced through the internet have been reported to contain the designer anabolic androgenic steroids [1',2']isoxazolo[4',5':2,3]-5α-androstan-17ß-ol (furazadrol F) and [1',2']isoxazolo[4',3':2,3]-5α-androstan-17ß-ol (isofurazadrol IF). These steroids contain an isoxazole fused to the A-ring and were designed to offer anabolic activity while evading detection, raising concerns over the potential for abuse of this preparation in sports. The metabolism of Furazadrol (F:IF, 10:1) was studied by in vivo methods in greyhounds. Urinary phase II Furazadrol metabolites were detected as glucuronides after a controlled administration. These phase II metabolites were subjected to enzymatic hydrolysis by Escherichia coli ß-glucuronidase to afford the corresponding phase I metabolites. Using a library of synthetically derived reference materials, the identities of seven urinary Furazadrol metabolites were confirmed. Major confirmed metabolites were isofurazadrol IF, 4α-hydroxyfurazadrol 4α-HF and 16α-hydroxy oxidised furazadrol 16α-HOF, whereas the minor confirmed metabolites were furazadrol F, 4ß-hydroxyfurazadrol 4ß-HF, 16ß-hydroxyfurazadrol 16ß-HF and 16ß-hydroxy oxidised furazadrol 16ß-HOF. One major hydroxyfurazadrol and two dihydroxyfurazadrol metabolites remained unidentified. Qualitative excretion profiles, limits of detection and extraction recoveries were established for furazadrol F and major confirmed metabolites. These investigations identify the key urinary metabolites of Furazadrol following oral administration, which can be incorporated into routine screening by anti-doping laboratories to aid the regulation of greyhound racing.