Urinary metabolites indicative of the administration of hypoxen monitored by liquid chromatography-high resolution/accurate mass tandem mass spectrometry

Hypoxen, a poly(dihydroxyphenylene) thiosulfonate-based drug, has been investigated concerning its effect on mitochondrial respiration and the utilization of lactate, especially in the context of strenuous exercise. Since 2023, patterns of use regarding hypoxen amongst the athletic population are monitored by the World Anti-Doping Agency (WADA) and its accredited anti-doping laboratories, necessitating information on suitable urinary markers indicative of the administration of hypoxen. In this exploratory study, urine samples collected post-administration of 1.5 and 2.0 g of hypoxen were analyzed by means of liquid chromatography-high resolution/high mass accuracy (tandem) mass spectrometry, which allowed for the identification of eight analytes that were plausibly attributable to metabolites of hypoxen. The identified species were assigned to the unconjugated species of S-(2,2',5,5'-tetrahydroxy-[1,1'-biphenyl]-3-yl) sulfurothioate and its glucuronide and additional tentatively identified analytes comprising a mercaptobenzene core structure. Including the identified markers into routine doping control analytical procedures enabled the detection of hypoxen use in athletes' doping control samples, thus contributing relevant information to WADA's monitoring program.

Chromatographic-mass spectrometric analysis of peptidic analytes (2-10 kDa) in doping control urine samples

Peptides with a molecular mass between 2 and 10 kDa that are prohibited in elite sports usually require dedicated sample preparation and mass spectrometric detection that commonly cannot be combined with other (lower molecular mass) substances. In most instances, the physicochemical differences are too significant to allow for a generic analytical procedure. A simplification of established and comparably complex analytical approaches is therefore desirable and has been accomplished in the context of this study. With urine samples representing still the most frequently collected doping control specimens, efficient extraction of peptidic analytes from this matrix was a major goal of this method, as demonstrated for the included compounds such as insulins (human, lispro, aspart, glulisine, tresiba, glargine metabolite, bovine insulin, porcine insulin), growth hormone-releasing hormones (sermorelin, CJC-1295, tesamorelin) incl. their respective metabolites, insulin-like-growth factors (long-R3 -IGF-I, R3 -IGF-I, des1-3 -IGF-I), synacthen, gonadorelin and mechano growth factors (human MGF, MGF-Goldspink). Sample preparation and detection are controlled by five internal standards, covering all five included peptide drug categories. Nearly all requirements of the recent technical documents from the World Anti-Doping Agency (WADA) considering their minimum required performance levels (MRPL) are fulfilled, and the method was validated for its utilisation as initial testing procedure in doping controls. Finally, the approach was applied to authentic post-administration study urine samples (for insulins and gonadorelin) in order to provide proof of principle.

Mass spectrometry in sports drug testing-Analytical approaches and the athletes' exposome

Test methods in anti-doping, most of which rely on the most modern mass spectrometric instrumentation, undergo continuous optimization in order to accommodate growing demands as to comprehensiveness, sensitivity, retrospectivity, cost-effectiveness, turnaround times, etc. While developing and improving analytical approaches is vital for appropriate sports drug testing programs, the combination of today's excellent analytical potential and the inevitable exposure of humans to complex environmental factors, specifically chemicals and drugs at the lowest levels, has necessitated dedicated research, particularly into the elite athlete's exposome. Being subjected to routine doping controls, athletes frequently undergo blood and/or urine tests for a plethora of drugs, chemicals, corresponding metabolic products, and various biomarkers. Due to the applicable anti-doping regulations, the presence of prohibited substances in an athlete's organism can constitute an anti-doping rule violation with severe consequences for the individual's career (in contrast to the general population), and frequently the question of whether the analytical data can assist in differentiating scenarios of 'doping' from 'contamination through inadvertent exposure' is raised. Hence, investigations into the athlete's exposome and how to distinguish between deliberate drug use and potential exposure scenarios have become a central topic of anti-doping research, aiming at supporting and consolidating the balance between essential analytical performance characteristics of doping control test methods and the mandate of protecting the clean athlete by exploiting new strategies in sampling and analyzing specimens for sports drug-testing purposes.