Bioanalysis of Dermorphin, an Opioid Peptide in Equine Urine: Benefit of the VIP-Heated ESI Technology for the Quantitative Analysis of Thermally Labile Molecules

Dermorphin is an opioid hepta-peptide derived from the skin secretions of South American frogs (Phyllomedusa sauvagei)1. It is 30-to-40 times more potent an analgesic than morphine2 and is unique because it contains D-alanine, a property that makes it highly resistant to protease mediated degradation (Figure 1). While d-amino acid peptides are sought after for their low immunogenic response and in peptidomimetic drug design, it was dermorphin’s use in horse racing that catapulted this opioid peptide from obscurity into the headlines. The pain-killing properties of dermorphin were used to drive racehorse performance beyond normal physical limits often injuring the animal. As a result, dermorphin is now a Class I prohibited substance as decreed by the Association of Racing Commissioners International (RCI) Model Rules3.