Statistical significance of hair analysis of clenbuterol to discriminate therapeutic use from contamination

• Published in: Drug testing and analysis 2014-11, Vol.6 (11-12), p.1108-1116
• Main Authors: Krumbholz, Aniko, Anielski, Patricia, Gfrerer, Lena, Graw, Matthias, Geyer, Hans, Schänzer, Wilhelm, Dvorak, Jiri, Thieme, Detlef
• Format: Article
• Language: English
• Subjects: Adolescent; Adrenergic beta-2 Receptor Agonists - analysis; Adrenergic beta-2 Receptor Agonists - therapeutic use; Adult; Bicycling; clenbuterol; Clenbuterol - analysis; Clenbuterol - therapeutic use; doping; Doping in Sports; Female; Food Contamination; hair; Hair - chemistry; Humans; Indicators and Reagents; Male; Mexico; Reference Standards; Reproducibility of Results; Soccer; Young Adult
• ISSN: 1942-7603; 1942-7611
• DOI: 10.1002/dta.1746

Clenbuterol is a well‐established β2‐agonist, which is prohibited in sports and strictly regulated for use in the livestock industry. During the last few years clenbuterol‐positive results in doping controls and in samples from residents or travellers from a high‐risk country were suspected to be related the illegal use of clenbuterol for fattening. A sensitive liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed to detect low clenbuterol residues in hair with a detection limit of 0.02 pg/mg. A sub‐therapeutic application study and a field study with volunteers, who have a high risk of contamination, were performed. For the application study, a total dosage of 30 µg clenbuterol was applied to 20 healthy volunteers on 5 subsequent days. One month after the beginning of the application, clenbuterol was detected in the proximal hair segment (0‐1 cm) in concentrations between 0.43 and 4.76 pg/mg. For the second part, samples of 66 Mexican soccer players were analyzed. In 89% of these volunteers, clenbuterol was detectable in their hair at concentrations between 0.02 and 1.90 pg/mg. A comparison of both parts showed no statistical difference between sub‐therapeutic application and contamination. In contrast, discrimination to a typical abuse of clenbuterol is apparently possible. Due to these findings results of real doping control samples can be evaluated. Copyright © 2014 John Wiley & Sons, Ltd. An application study of clenbuterol in a sub‐therapeutic range and a field study with volunteers with high contamination risk were performed to detect clenbuterol residues in low concentrations in hair. Concentrations were detected between 0.02 and 4.76 pg/mg and no statistical differences were observed between the groups. Findings were used to interpret analytical results of doping control cases.