Characterization of a non-approved selective androgen receptor modulator drug candidate sold via the Internet and identification of in vitro generated phase-I metabolites for human sports drug testing

• RATIONALE: Potentially performance-enhancing agents, particularly anabolic agents, are advertised and distributed by Internet-based suppliers to a substantial extent. Among these anabolic agents, a substance referred to as LGD-4033 has been made available, comprising the core structure of a class of selective androgen receptor modulators (SARMs). METHODS: In order to provide comprehensive analytical data for doping controls, the substance was obtained and characterized by nuclear magnetic resonance spectroscopy (NMR) and liquid chromatography/electrospray ionization high resolution/high accuracy tandem mass spectrometry (LC/ESI-HRMS). Following the identification of 4-(2-(2,2,2-trifluoro-1-hydroxyethyl) pyrrolidin-1-yl)-2-(trifluoromethyl) benzonitrile, the substance was subjected to in vitro metabolism studies employing human liver microsomes and Cunninghamella elegans (C. elegans) preparations as well as electrochemical metabolism simulations. RESULTS: By means of LC/ESI-HRMS, five main phase-I metabolites were identified as products of liver microsomal preparations including three monohydroxylated and two bishydroxylated species. The two most abundant metabolites (one mono-and one bishydroxylated product) were structurally confirmed by LC/ESI-HRMS and NMR. Comparing the metabolic conversion of 4-(2-(2,2,2-trifluoro-1-hydroxyethyl) pyrrolidin-1-yl)-2-(trifluoromethyl) benzonitrile observed in human liver microsomes with C. elegans and electrochemically derived metabolites, one monohydroxylated product was found to be predominantly formed in all three methodologies. CONCLUSIONS: The implementation of the intact SARM-like compound and its presumed urinary phase-I metabolites into routine doping controls is suggested to expand and complement existing sports drug testing methods.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinsk bioteknologi -- Medicinsk bioteknologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Medical Biotechnology -- Medical Biotechnology (hsv//eng)

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ref (subject category)

art (subject category)