Volume 2, Issue 11-12 p. 589-598
Research Article

Characterization of in vitro generated metabolites of the selective androgen receptor modulators S-22 and S-23 and in vivo comparison to post-administration canine urine specimens

Mario Thevis

Corresponding Author

Mario Thevis

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany.Search for more papers by this author
Enrico Gerace

Enrico Gerace

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

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Andreas Thomas

Andreas Thomas

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

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Simon Beuck

Simon Beuck

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

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Hans Geyer

Hans Geyer

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

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Nils Schlörer

Nils Schlörer

Institute of Organic Chemistry, University of Cologne, Greinstraße 4, 50939 Cologne, Germany

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Jeffrey D. Kearbey

Jeffrey D. Kearbey

GTx, Inc., 3 North Dunlap Street, Memphis, Tennessee 38163, USA

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James T. Dalton

James T. Dalton

GTx, Inc., 3 North Dunlap Street, Memphis, Tennessee 38163, USA

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Wilhelm Schänzer

Wilhelm Schänzer

Institute of Biochemistry - Center for Preventive Doping Research, German Sport University Cologne, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany

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First published: 22 October 2010
Citations: 42

Abstract

Selective androgen receptor modulators (SARMs) have great therapeutic potential in various diseases including cancer cachexia, sarcopenia, and osteoporosis, and the number of drug candidates has been growing over the last decade. The SARM drug candidates S-22 and S-23 belong to one of the most advanced groups of androgen receptor modulators and are based on an arylpropionamide-derived core structure. Due to their anabolic effects, SARMs have been prohibited in elite sports and have been a subject of sports drug testing programmes since January 2008. Consequently, the structure of analytically useful urinary metabolites should be elucidated to provide targets for sensitive and retrospective analysis. In the present study, the phase-I and -II metabolism of S-22 and S-23 was simulated using hepatic human enzymes, and resulting metabolites were characterized by means of state-of-the-art mass spectrometric approaches employing high resolution/high accuracy Orbitrap mass spectrometry. Subsequently, the newly defined target compounds including the glucuronic acid conjugates of S-22 and S-23, their corresponding monohydroxylated and bishydroxylated analogs, as well as their B-ring depleted counterparts were implemented into an existing routine doping control procedure, which was examined for its specificity for the added substances. In order to obtain proof-of-concept data for authentic urine specimens, canine urine samples collected up to 72 h after oral administration of S-22 to dogs were analyzed using the established approach outlining the capability of the presented assay to detect the glucuronide of S-22 as well as the B-ring-depleted metabolite (M3) in all samples following therapeutic (31.4 µg/kg) dosing. Finally, M3 was chemically synthesized, characterized by nuclear magnetic resonance spectroscopy and high resolution/high accuracy mass spectrometry, and chosen as primary target for future doping control analyses. Copyright © 2010 John Wiley & Sons, Ltd.