Determination and enantioselective separation of zilpaterol in human urine after mimicking consumption of contaminated meat using high‐performance liquid chromatography with tandem mass spectrometry techniques

Abstract

Rationale: The synthetic β-adrenoreceptor agonist zilpaterol is legitimately used as an animal feed supplement in selected countries due to its known effects on lipolysis and protein biosynthesis. These pharmacological characteristics of zilpaterol have contributed to its classification as doping agent in sport by the World Anti-Doping Agency. However, the use as a feed supplement can lead to residues of the drug in edible tissues and, possibly, also in the urine of consumers.Methods: To provide urinary elimination profiles of microdosed zilpaterol and to determine whether the ingestion of zilpaterol below or at the acceptable daily intake level of 0.04 μg/kg bodyweight can result in an adverse analytical finding (AAF) in doping controls, healthy volunteers were administered single or multiple oral doses of 0.5 μg or 3 μg zilpaterol to mimic ingestion of contaminated cattle meat. Urine samples were collected and analyzed using a validated high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/ MS) method and a newly developed chiral high-performance liquid chromatographyatmospheric pressure chemical ionization-tandem mass spectrometry (HPLC-APCI-MS/MS) method.Results: Urinary peak concentrations of zilpaterol were observed for all volunteers 1.5-12.5 h after ingestion, and maximum levels >5 ng/mL, which would constitute an AAF in doping controls, were found after the intake of 3 μg of zilpaterol on five consecutive days in one out of five study participants. Noteworthy, the enantiomeric ratio of excreted zilpaterol remained constant over time. Conclusion:This study provides first insights into the urinary excretion of microdosed zilpaterol. Furthermore, a method was successfully developed and applied for the separation of the zilpaterol enantiomers with mass spectrometric detection.

Evaluating Impact of Social Media Marketing, Celebrity Endorsement and E-WOM on Online Repurchase Intention with the Mediating Role of Perceived Usefulness

“…Associations have exceptional controlling command over made spokespersons since they cultivate these qualities. They can develop characters agreeable with their brands and ideal vested parties, and assurance that these characters guarantee simply a solitary explicit thing (Euler, Wagener, Thomas, & Thevis, 2022). On the other hand, in the occurrence of hotshot endorsers, associations have confined control over the whiz's persona as they have made their public persona all through the long haul.…”

Annual banned‐substance review—Analytical approaches in human sports drug testing 2021/2022–

“…A different but yet related scenario was investigated by Euler et al, who simulated the ingestion of residues of zilpaterol, a feed additive approved for cattle in the farming industry 52 . Study participants ingested single or multiple doses of either 0.5 μg or 3 μg of zilpaterol, and urine samples were collected before and up to 12 days after administration.…”

“…With an LOD of 9 pg/ml, RAD140 (and its metabolites) was detected up to 9 days following a single oral dose of 1 μg and up to 38 days after the consecutive administration of 50 μg/day for 5 days. Various metabolite ratios indicated timedependent changes, which were however not as pronounced as in case of LGD-4033; nevertheless, the mere presence/absence of some metabolites as well as selected abundance ratios of hydroxylated species were found to provide useful information contributing to verifying or falsifying potential drug exposure scenarios.A different but yet related scenario was investigated by Euler et al, who simulated the ingestion of residues of zilpaterol, a feed additive approved for cattle in the farming industry 52. Study participants ingested single or multiple doses of either 0.5 μg or 3 μg of zilpaterol, and urine samples were collected before and up to 12 days after administration.…”

Presence of β2‐agonist growth promoters in human urine samples: GC‐MS/MS evaluation of the excretion profiles of ractopamine administered in microdoses

“…Recently, the elimination profiles of ZIL administered in single or repeated oral micro‐doses of 0.5 and 3 μg were studied in several volunteers. Maximum urinary levels were reached from 1.5 to 12.5 h post‐dosing, and while in most cases all were below 1 and 2 ng/ml, the MRL set by WADA was exceeded in 1 out of 10 volunteers having consumed the largest dose for 5 days with a measured peak concentration at 6.2 ng/ml 25 …”

“…Maximum urinary levels were reached from 1.5 to 12.5 h post-dosing, and while in most cases all were below 1 and 2 ng/ml, the MRL set by WADA was exceeded in 1 out of 10 volunteers having consumed the largest dose for 5 days with a measured peak concentration at 6.2 ng/ml. 25 In comparison, very little is known about the excretion of RAC in humans, and it is limited to a single report, albeit inaccessible, widely referred to and cited. 26 After the administration of 40 mg to 6 young male volunteers, results were described as follows:…”