Separation and Online Characterization of Intact Monoclonal Antibody Charge Variants by Capillary Isoelectric Focusing-Mass Spectrometry Method (CAT#: STEM-ET-0350-ZJF)

Introduction

This service provides an online capillary isoelectric focusing-mass spectrometry (CIEF-MS) method for monoclonal antibody (mAb) charge variant analysis using an electrokinetically pumped sheath-flow nanospray ion source and a time-of-flight MS with pressure-assisted chemical mobilization. Use of recombinant mAbs as therapeutics is rapidly growing throughout the worldwide biopharma industry. Unlike synthesized chemical drugs, biologics are cell-originated and are subject to post-translational modifications (PTMs) such as glycosylation, C-terminal lysine truncation, deamidation, disulfide-scrambling, glycation, and methionine or tryptophan oxidation. As these PTMs usually lead to changes in protein isoelectric point (pI), mAb drug substances are known to exhibit charge heterogeneity, represented by multiple charge variants with different pIs. Comprehensive characterization of mAb charge variants is crucial, as the variants may affect the in vitro and in vivo properties related to its activity, safety, developability, and quality. In addition, charge variant characterization is also important for developing biosimilar mAbs.