Determination of N-desmethyl- and N-bisdesmethyl metabolites of Sibutramine in doping control analysis using liquid chromatography-tandem mass spectrometry

Eur. J. Mass Spectrom. DOI: 10.1255/ejms.797

Determination of N-desmethyl- and N-bisdesmethyl metabolites of Sibutramine in doping control analysis using liquid chromatography-tandem mass spectrometry

Mario Thevis^* Gerd Sigmund, Anna-Katharina Schiffer and Wilhelm Schänzer
Institute of Biochemistry and Center for Preventive Doping Research, German Sport University Cologne, Carl-Diem Weg 6, 50933 Cologne, Germany. Email: m.thevis@biochem.dshs-koeln-de

ABSTRACT:

Since January 2006, the list of prohibited substances established by the World Anti-Doping Agency includes the antidepressant / anti-obesity drug Sibutramine. Due to its rapid degradation to its active metabolites N-desmethyl and N-bisdesmethyl Sibutramine, reference compounds were synthesized and included into an existing screening assay to allow the unambiguous determination of these metabolic products in human urine using liquid-liquid extraction followed by liquid chromatography/tandem mass spectrometry. Characteristic product ions, obtained after electrospray ionization and collision-induced dissociation, were elucidated using high resolution/high accuracy mass measurements with a hybrid linear ion trap/orbitrap mass analyzer. Based on diagnostic product ions, the extended screening procedure was validated for both Sibutramine metabolites using a triple quadrupole mass spectrometer. Items such as lower limits of detection (6–40 ng mL^–1), recoveries (39–42%), intraday precision (low: 5.5–10.6%, medium: 4.9–5.9%), high: 12.8–16.4%) and interday precision (low: 15.0–22.8%, medium: 17.7–18.6%), high: 16.5–25.6%) were evaluated, and a clinical spot urine sample was analyzed to demonstrate the applicability of the developed assay in sports drug testing.

Keywords: sport, stimulant, doping, antidepressant, fragmentation, collision-induced dissociation

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