Developing A Quantitative Surrogate Peptide Assay: Peptide Mapping Through MRM Optimization For Measuring Dulaglutide In A Rat PK Study

The development of fusion protein therapeutics, such as dulaglutide (marketed as TRULICITY™), is experiencing significant growth, which creates a pressing need for universal and efficient workflows to support the rapid development of quantitative LC-MS/MS assays. This application note presents a comprehensive and streamlined workflow specifically designed for the assay development of Fc-containing therapeutics. The process begins with peptide mapping experiments, which are employed to thoroughly characterize the therapeutic protein and identify suitable peptides for accurate quantification. Following this, multiple reaction monitoring (MRM) transitions are optimized using an automated workflow that integrates MassLynx with Skyline, enhancing both precision and efficiency. Sample preparation is carried out using a generic immunoaffinity capture method, followed by a fast and reproducible enzymatic digestion protocol. To ensure selectivity and sensitivity, peptide-level solid-phase extraction (SPE) is employed.

Explore how this robust workflow enables the assay to achieve a lower limit of quantification (LLOQ) as low as 1 ng/mL for dulaglutide.