Detecting AOD9604 Abuse: New Method Identifies Stable Metabolite for Longer Detection
Background
AOD9604 is a synthetic peptide derived from human growth hormone (hGH) fragment 177-191, with an added N-terminal tyrosine. It's known for its lipolytic (fat-burning) properties without the diabetogenic side effects often associated with full-length hGH, making it attractive as a performance-enhancing drug. Consequently, it is banned by the World Anti-doping Agency (WADA), yet its presence has been confirmed in confiscated vials. This study addresses the critical need to develop robust analytical methods for detecting AOD9604 and its metabolites to extend the window of abuse detection in athletes.
Results
The validated solid-phase extraction method demonstrated excellent performance for AOD9604 detection in urine, achieving a limit of detection (LOD) of 50 pg/mL. The method exhibited good linearity, precision of <20%, high specificity, and a recovery rate of 62%. Through in vitro incubation experiments, six potential metabolites of AOD9604 were identified in both serum and urine. Quantification of these metabolites in serum revealed a single, particularly stable metabolite, consisting of the amino acid sequence CRSVEGSCG, which was significantly more resistant to degradation compared to the other identified metabolites or the parent AOD9604 compound itself. This stable metabolite offers a promising target for extending the detection window.
Why It Matters
This research provides a critical advancement for anti-doping efforts, offering a highly sensitive and reliable method for detecting AOD9604 abuse. The identification of a significantly more stable metabolite, CRSVEGSCG, is particularly impactful, as it could enable anti-doping agencies to detect AOD9604 use over a much longer period than currently possible with the parent compound alone. Future steps involve integrating this stable metabolite into routine anti-doping screening protocols and potentially conducting in vivo studies to confirm its extended detection window in humans.