Unraveling the complexity of anti-doping analysis: reassessing meldonium detection and doping verdicts in a case study

BACKGROUND

The precision and accuracy of mass spectrometry (MS) made it a fundamental tool in anti-doping analysis. High-resolution (HR) mass spectrometers significantly improved compound identification. This study systematically analyzes data from an athlete (Subject 1) who tested positive for meldonium and compares it with data from a healthy volunteer (Subject 2) to examine the correctness of the doping verdict.

CASE PRESENTATION

The documentation related to Subject 1 was thoroughly processed and analyzed. A study involving a volunteer (Subject 2) replicated Subject 1 regimen and urine sample collection for data alignment with anti-doping results, with Subject 2 reporting not using meldonium. The anti-doping agency's analysis of Subject 1 showed the presence of meldonium at a concentration close to the established cut-off level. However, a closer examination revealed that one specific ion, crucial for meldonium identification, was absent from the mass spectra. Analyzing Subject 2 data, using the same methodology, the absence of the specific ion was confirmed, even though the volunteer did not consume meldonium. The European directive and the method that was validated and cited by the anti-doping agency identified meldonium on at least four specific ions, whereas the anti-doping analysis used only three ions. This discrepancy compromises the specificity of meldonium identification.

CONCLUSIONS

To enhance the analytical methodology, two strategic interventions are suggested: adjusting the meldonium cut-off value and expanding the analysis to include meldonium metabolites. By addressing these avenues, the precision of meldonium detection and doping verdicts can be improved. In conclusion, this study challenges the anti-doping agency's verdict and prompts a reevaluation of meldonium detection methodologies in anti-doping measures.

The atypical excretion profile of meldonium: Comparison of urinary detection windows after single- and multiple-dose application in healthy volunteers

Following a one-year monitoring program providing unequivocal analytical evidence for a high prevalence in international elite sports, meldonium has been included in the World Anti-Doping Agency's (WADA) list of prohibited substances that came into effect on 1 January 2016. Despite of the polar and hydrophilic nature of the molecule, an unusual long detection window was observed in pilot elimination studies. Consequently, in the present study, urinary excretion profiles after single-dose (5 volunteers, 1×500mg) and multiple-dose oral application (5 volunteers; 2×500mg/day for 6days) were determined in order to facilitate the result management concerning meldonium findings in doping controls. Particularly the option to differentiate between recent use and tapering concentrations was studied. Urinary meldonium concentrations were determined using an analytical approach based on hydrophilic interaction liquid chromatography and high resolution tandem mass spectrometry. The study corroborates the hypothesis of a non-linear, dose-depended and biphasic excretion profile after oral application of meldonium and demonstrates that urinary detection windows are of considerable extent with up to 65 and 117days (concentrations>LOQ of 10ng/mL) following single- and multiple-dose applications, respectively.

Determination of mildronate in human plasma and urine by liquid chromatography–tandem mass spectrometry

A sensitive and selective analytical method based on liquid chromatography-triple-quadrupole mass spectrometer has been developed to determine mildronate in human plasma and urine. The aim of this work was to find a valid method to study the pharmacokinetic profiles of mildronate in humans. Mildronate is a heart protection medicine, a carnitine's structural analogue, so levocarnitine was used as an internal standard for quantification. Under the electrospray ionization source positive ion mode, calibration curves with good linearities (r=0.9998 for plasma sample and r=0.9999 for urine sample) were obtained in the range of 1.0-20,000 ng ml(-1) for mildronate. The detection limit was 1 ng ml(-1). Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of mildronate in humans, and to the best of our knowledge, this is the first report on LC-MS-MS analysis of mildronate in plasma and urine.

Analysis of carnitine and acylcarnitines in urine by capillary electrophoresis

A capillary electrophoresis method is described for the simultaneous analysis of carnitine and short-chain acylcarnitines in aqueous standard solutions and urine samples. Samples were worked up using silica gel extraction and derivatization with 4'-bromophenacyl trifluoromethanesulfonate. Separation was performed in less than 8 min using a binary buffer system containing phosphate/phosphoric acid and sodium dodecyl sulfate. 3-(2,2,2-Trimethylhydrazinium)propionate (mildronate) was used as an internal standard. The method was developed with aqueous standard solutions and then applied successfully to spiked and unspiked human urine samples. The limit of detection for both carnitine and acetylcamitine is 3 microM.