Publication / Source: Bioanalysis 4(17)
Authors: Wang Y, Qu Y, Bellows LC, Ahn SJ, Burkey LJ, Taylor WS
Background: Davalintide, an investigational therapeutic peptide for the treatment of obesity, is rapidly metabolized by enzymatic cleavage of its N-terminal lysine residue to produce an active des-Lys metabolite in vivo. While a sensitive ELISA assay is available, it is unable to distinguish davalintide from its metabolite. Consequently, we developed an online SPE–LC–MS/MS method for simultaneous quantification of the drug and its active metabolite in beagle and rat plasma samples and compared the resulting pharmacokinetic profiles with those determined by ELISA. Results: The total concentration of active drug measured by ELISA correlated well with the total concentration of davalintide and its metabolite using online SPE–LC–MS/MS. Conclusion: The technique is a viable alternative to immunochemistry-based methods for peptide quantitation in terms of sensitivity, reproducibility and specificity, and importantly, does not require developing antibody-based reagents.