Minimalistic Sample Preparation Strategies for LC-MS Quantification of Large Molecule Biopharmaceuticals: a Case Study Highlighting Alpha-1 Antitrypsin Protein.

BACKGROUND:Large molecule biotherapeutics pose a distinctive bioanalytical challenge for LC-MS assay development, particularly when optimizing sample enrichment steps. Alpha-1 antitrypsin (AAT) is used as an example for highlighting large-molecule assay-development strategies.RESULTS:Two sensitive and selective LC-MS/MS-based quantification assays were developed. Fit-for-purpose assay qualifications for BAL and serum matrices were performed by assessing sensitivity, precision and accuracy, dilution linearity and interferences.CONCLUSION:Our approach to sample preparation focuses on optimizing the simplest methodology necessary to generate fit-for-purpose bioanalytical assays. To measure AAT protein levels in preclinical species with selectivity and increased assay sensitivity, a minimalistic sample preparation strategy was adopted that included either traditional direct digestion or a more complicated immunoprecipitation enrichment process.