In vitro metabolic profiling of weight-loss-inducing amylin receptor agonists in the context of preventive doping research.

Peptide hormone-based weight-loss therapeutics have gained increasing attention, driven amongst other reasons, by the clinical and commercial success of semaglutide. Their increasing accessibility raises concerns about their potential misuse in sports, especially in disciplines where weight management is decisive for athletic performance. Semaglutide has been included in the World Anti-Doping Agency's monitoring program since 2024. Given that amylin signalling is a key therapeutic target for next-generation weight-loss drugs, amylin receptor agonists such as pramlintide, cagrilintide and KBP-066 also warrant consideration as to metabolism and detection strategies in sports drug testing programs. This study aimed to characterize the metabolic profiles of pramlintide, cagrilintide and KBP-066, identify analytically suitable metabolites and develop and validate a LC-MS/MS-based detection approach. Comprehensive in vitro models, including human skin S9 fraction, kidney S9 fraction and biological fluids, were used to investigate metabolic pathways. HRMS/MS was employed to characterize metabolites and evaluate their suitability as analytical targets. For comparison, authentic post-administration rat samples were analysed for cagrilintide and respective biotransformation products. All three peptides underwent N-terminal and C-terminal degradation, yielding multiple stable metabolic products suitable as detection targets. Cagrilintide metabolites predicted from in vitro experiments were observed in authentic post administration rat plasma samples, confirming in vivo relevance. Finally, suitable preparation and detection methods were established and validated. This study provides the first systematic metabolic characterization of pramlintide, cagrilintide and KBP-066. The identified metabolites and LC-MS/MS detection approach offer a foundation for future monitoring of emerging weight-loss peptide hormone analogues in anti-doping contexts.