ABSTRACT
This chapter provides a description of what are impurities and drug-related substances for therapeutic proteins and in particular for monoclonal antibody (mAbs). It explains how these compounds are formed during the manufacturing and/or storage of the drug, and their potential impact on the biological activity of the biopharmaceutical. The application of capillary electrophoresis (CE) techniques for biopharmaceutical analysis is continuously growing. The sources of natural heterogeneity of mAbs (post-translational modifications) are briefly introduced, while the specific domain of QC performed after mAb compounding at the hospital is presented. The chapter also explains the state-of-the-art of CE-based methods (mostly CZE, CGE, and CIEF) applicable for in- process controls, controls of drug-related substances, and identity control after mAb compounding. It discusses the specificity of each CE mode, their respective advantages and drawbacks, and their possible evolution toward miniaturization or coupling with mass spectrometry.
