Investigation of in vitro generated metabolites of LGD-4033, a selective androgen receptor modulator, in homogenized camel liver for anti-doping applications

Rationale: The use of selective androgen receptor modulators (SARM) in sports is prohibited by the World Anti-Doping Agency (WADA) due to their potential as performance-enhancing drugs, offering an unfair advantage. LGD-4033 is a SARM known for its similarities to anabolic steroids and can be easily purchased online, leading to increased availability and misuse. Adverse analytical findings have revealed the presence of SARMs in dietary supplements. Although LGD-4033 misuse has been reported in human sports over the years, concerns also arise regarding its illicit use in animal sports, including camel racing. Although various studies have investigated the metabolism of LGD-4033 in humans, horse, and other species, there is limited research specifically dedicated to racing camels. Methods: This study focuses on the in vitro metabolism of LGD-4033 in homogenized camel liver using liquid chromatography–high-resolution mass spectrometry (LC-HRMS) to identify and characterize the metabolites. Results: The findings indicated the presence of 12 phase I metabolites and 1 phase II metabolite. Hydroxylation was responsible for the formation of the main phase I metabolites that were identified. A glucuronic acid conjugate of the parent drug was observed in this study, but no sulfonic acid conjugate was found. The possible chemical structures of these metabolites, along with their fragmentation patterns, were identified using MS. Conclusions: These findings provide valuable insights into the metabolism of LGD-4033 in camels and aid in the development of effective doping control methods for the detection of SARMs in camel racing.