Urinary phenylethylamine metabolites as potential markers for sports drug testing purposes

Carbon isotope ratios of phenethylamine and its urinary metabolite phenylacetylglutamine

Phenethylamine (PEA) is a naturally occurring trace amine that acts as a modulator in the central nervous system. It is widely sold as a dietary supplement and advertised for its mood enhancing effects and should support weight loss. It is prohibited in sports and itemized as a stimulant on the Prohibited List issued by the World Anti-Doping Agency (WADA). After oral administration of PEA, its urinary concentration is found only slightly elevated while metabolites of PEA show a significant increase. Besides 2-(2-hydroxyphenyl)acetamide sulfate, especially phenylacetylglutamine (PAG) was found at significantly elevated urinary concentrations after the administration. Due to large inter- and intra-individual variations in urinary concentrations of all metabolites, establishing a concentration or concentration ratio-based threshold remained complicated to unambiguously identify post-administration samples. In accordance with the approach employed in detecting testosterone misuse, the applicability of isotope ratio mass spectrometry to differentiate between endogenously elevated concentrations and PEA administrations was investigated. A method encompassing solid-phase extraction combined with acetylation and high-performance liquid chromatography (HPLC)-based clean-up was developed and validated for PEA. The more abundant metabolite PAG was purified by a direct injection approach on the HPLC and could be analyzed without the need for derivatization. Both methods were validated considering applicable WADA regulations. A reference population encompassing n = 57 samples was investigated to establish population-based thresholds considering the carbon isotope ratios (CIRs) found at natural abundance for PAG. The derived threshold was tested for its applicability by re-analysis of numerous post-administration samples encompassing single- and multi-dose trials.

Temperature and time after urine collection affect the detection of phenethylamine, a substance prohibited in sports

2-Phenylethylamine (phenethylamine) and its derivatives are stimulant drugs, which are prohibited in sports because of their potential performance-enhancing properties. If phenethylamine is detected in an athlete's urine, the athlete may be subjected to serious sanctions, such as disqualification for both domestic and international competitions. Given the serious consequences athletes face for phenethylamine detection, great care should be taken to avoid false positive tests. In forensic medicine, it is widely known that phenethylamine is produced by putrefactive bacteria in autopsy urine samples; it is possible that this process could also occur in an athlete's urine sample without proper storage. In this study, human urine samples were stored at -20, 4, or 22°C for 14 days, and phenethylamine in the samples was quantitatively analyzed using ultra-high-performance liquid chromatography-tandem mass spectrometry. No phenethylamine was detected in urine samples stored at -20°C throughout 14-day period. Nevertheless, phenethylamine was detected after 6 days in these samples stored at 4°C and after only 1 day in samples stored at 22°C. Additionally, the concentration of phenethylamine in these samples increased each day after detection. These results suggest that urine samples should be stored immediately at -20°C after collection when testing athletes for phenethylamine, especially if the sample must be stored for extended period before testing.

Annual banned-substance review-Analytical approaches in human sports drug testing 2021/2022

Also in 2021/2022, considerable efforts were invested into advancing human sports drug testing programs, recognizing and taking into account existing as well as emerging challenges in anti-doping, especially with regard to substances and methods of doping specified in the World Anti-Doping Agency's 2022 Prohibited List. In this edition of the annual banned-substance review, literature on recent developments published between October 2021 and September 2022 is summarized and discussed. Focus is put particularly on enhanced analytical approaches and complementary testing options in human doping controls, appreciating the exigence and mission in anti-doping and, equally, the contemporary "new normal" considering, for example, the athlete's exposome versus analytical sensitivity and applicable anti-doping regulations for result interpretation and management.