title: Comparison of urine analysis and dried blood spot analysis for the detection of ephedrine and methylephedrine in doping control.
abstract: When the misuse of stimulants is determined in doping control tests conducted during the in-competition period, athletes are asked to account for the violation of the rules. This study was designed to evaluate whether the urinary threshold values (10 µg/mL) for ephedrine and methylephedrine set by the World Anti-Doping Agency (WADA) can be exceeded after the oral administration of each substance (25 mg). In addition, the study describes the validity of a liquid chromatography-tandem mass spectrometric method using dried blood spot testing to detect ephedrine and methylephedrine by comparing it to a quantitative laboratory urine assay. After administration of ephedrine, the urinary concentration of ephedrine did not exceed the threshold at 4-10 h in two subjects, whereas the threshold was exceeded in both the subjects at 12 h after administration. For methylephedrine, the urinary concentrations of all the subjects failed to reach the threshold for up to 10 h after administration. The concentrations reached the threshold at 12-24 h after administration in some volunteers. In contrast, the blood concentrations of ephedrine and methylephedrine reached their maximum levels at 2-8 h after administration. The blood concentrations showed a low inter-individual variability, and the results suggested that the urinary excretion of ephedrine and methylephedrine can be strongly affected by urine pH and/or urine volume. These facts suggest that urinary concentrations cannot reflect the psychoactive level of ephedrines in circulation. Thus, dried blood analysis might be suitable for the adequate detection of stimulants during in-competition testing.
authors: Anti-Doping Laboratory, LSI Medience Corporation, Tokyo, Japan.
authors: Asami
authors: A
authors: Kojima
authors: Anti-Doping Laboratory, LSI Medience Corporation, Tokyo, Japan.
authors: Yasunori
authors: Y
authors: Nishitani
authors: Anti-Doping Laboratory, LSI Medience Corporation, Tokyo, Japan.
authors: Mitsuhiko
authors: M
authors: Sato
authors: Anti-Doping Laboratory, LSI Medience Corporation, Tokyo, Japan.
authors: Shinji
authors: S
authors: Kageyama
authors: Medical Centre, Japan Institute of Sports Sciences, Tokyo, Japan.
authors: Michiko
authors: M
authors: Dohi
authors: Anti-Doping Laboratory, LSI Medience Corporation, Tokyo, Japan.
authors: Masato
authors: M
authors: Okano
mesh_terms: D000328:Adult; D002138:Calibration; D000697:Central Nervous System Stimulants / Q000097:blood* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid; D004300:Doping in Sports / Q000379:methods*; D059788:Dried Blood Spot Testing; D004809:Ephedrine / Q000031:analogs & derivatives* / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D015813:Substance Abuse Detection; D053719:Tandem Mass Spectrometry; D016482:Urinalysis
chemical_list: D000697:Central Nervous System Stimulants; C041707:N-methylephedrine; D004809:Ephedrine
keywords: LC-MS; doping; dried blood spot; ephedrine; methylephedrine; sports; urine