Distinction of clenbuterol intake from drug or contaminated food of animal origin in a controlled administration trial – the potential of enantiomeric separation for doping control analysis

ABSTRACT

The differentiation of clenbuterol abuse and unintentional ingestion from contaminated meat is crucial with respect to the valuation of an adverse analytical finding in human sports doping control. The proportion of the two enantiomers of clenbuterol may serve as potential discriminating parameter. For the determination of the individual enantiomers, specific methods were developed and validated for the different matrices under investigation based on chiral chromatography coupled to tandem mass spectrometry. Data are presented from the administration to humans of clenbuterol from a pharmaceutical preparation, and from cattle meat and liver containing residues. A shift in the proportion of the enantiomers in cattle meat is detected and this signature is also found in human urine after ingestion. Thus, an altered enantiomeric composition of clenbuterol may be used to substantiate athletes’ claims following adverse analytical findings in doping control. However, in meat, the enantiomeric composition was found to be highly variable. Species as well as tissue dependent variances need to be considered in interpreting enantiomer discrimination. Analysis of post administration urines from a controlled experiment comparing the administration of racemic clenbuterol from a registered pharmaceutical preparation and the administration of residue-containing meat and liver (nonracemic mixture) from treated animals is reported. Furthermore doping control samples from Mexican U17 World Championship 2011 of the Fédération Internationale de Football Association (FIFA), with adverse analytical findings for clenbuterol, were re-analysed.

GRAPHICAL ABSTRACT

KEYWORDS:

• Clenbuterol
• food residues
• enantiomers
• chiral SFC-MS/MS
• chiral LC-MS/MS
• cattle
• growth promoter
• doping

Acknowledgements

This project was funded by the World Anti-Doping Agency within their research grants 11A18SS and 13D23SS. It was carried out with support of Steiner & Co. Deutsche Arzneimittelgesellschaft mbH & Co. KG, Dr Andreas Springer, MS Core Facility Biosupramol of FU-Berlin, and the Ministry of Sport and Tourism of the Republic of Poland. The authors also thank the doping control laboratories of Lausanne and Cologne for providing samples from a controlled administration study and from FIFA U17 world championship in Mexico. Dr Groot (RIKILT) is acknowledged for her help with the animal experiments and the collection of the meat for human consumption.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary material

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Additional information

Funding

This work was supported by the World Anti-Doping Agency [11A18SS]; [13D23SS].