In Vitro Metabolism of Metonitazene in Camels: High-Resolution Mass Spectrometric Characterization for Doping Control

Novel psychoactive substances, especially those within the benzimidazole class such as metonitazene, are powerful psychoactive agents with considerable potential for misuse in both human and animal sports. Implementing a robust detection and monitoring system is crucial to ensure fair competition and welfare of the athletes involved.

In vitro studies were conducted using camel liver homogenates to investigate the metabolism of metonitazene in camels. The metabolites were analyzed using a Thermo Fisher Orbitrap Exploris LC-MS system. Method validation for qualitative determination was performed using in-house developed methods, while data analysis and metabolite identification were performed using the Compound Discoverer software.

A total of seven Phase I metabolites of metonitazene were successfully identified. The metabolic transformations were predominantly characterized by dealkylation reactions. These metabolites hold promise as potential markers for the long-term detection of metonitazene in camels for doping control applications.

This study highlights the effectiveness of advanced high-resolution LC-MS techniques in identifying and characterizing the in vitro metabolites of metonitazene in camels. Considering the high potency and potential for abuse of metonitazene in camel racing, the metabolites identified offer a valuable basis for establishing robust doping control strategies. These results support the development of regulatory frameworks designed to protect animal welfare and uphold the integrity of the sport.