LC/MS ‐MS and confirmation by LC/HRMS hair tests to evidence use of tizanidine by racing cyclists

AbstractTizanidine, an imidazoline derivative close to clonidine, is a central alpha-2 adrenergic receptor agonist. Therapeutically, the drug is used as a muscle relaxant under the trade names Sirdalud ™ or Zanaflex™. The drug is not prohibited by the World Anti-Doping Agency, but, for therapeutic purposes, can only be obtained via a nominative temporary use authorisation. The French public health police requested the laboratory to test for tizanidine in head hair specimens collected from inte rnational racing cyclists. Using LC/MS-MS and confirmation by LC/HRMS, after pH 9.5 borate buffer overnight incubation of 20 mg and subsequent solvents extraction, tizanidine was identified in the hair of 3 athletes at 1.1, 3.7 and 11.1 pg/mg. This is the first evidence that tizanidine is incorporat ed in human hair. However, it was not possible to interpret the data in terms of doses and frequency of use due to a lack of controlled study.
Source: Drug Testing and Analysis - Category: Drugs & Pharmacology Authors: Tags: RESEARCH ARTICLE Source Type: research