Application of high-resolution MS in the quantification of a therapeutic monoclonal antibody in human plasma

Background: Monoclonal antibodies are the fastest growing class of protein therapeutics. Ligand-binding assays have been the technique of choice for the quantification of these large proteins; however, LC-MS and more recently LC-HRMS have been gaining momentum as robust alternatives for the bioanalysis of antibodies in biological matrices. Results: Optimization of sample preparation and LC-HRMS analysis in MRMHR mode has allowed us to develop a highly specific dual-peptide targeted assay for the quantification of Rituximab, in human plasma. The linearity of the assay was established from 1.0 to 200 mu g/ml for both light and heavy chain surrogate peptides, with accuracy and precision within 15%. Conclusion: LC-HRMS can be an effective tool for the quantification of monoclonal antibodies in regulated bioanalysis.