Removal of Charge Variants Assay

Many hypothetical post-translational modifications may lead to changes in the charge distribution of monoclonal antibodies (mAbs), which may affect their biological activity. Characterization and removal of these charge variants are key quality requirements to ensure stability and process consistency. Creative Biolabs provides a series of experimental assays to remove charge variants.

Introduction of Charge Variants

Based on the understanding and identification of key targets involved in inflammation, tumors and autoimmune diseases, mAbs are now recognized as pharmacological therapies. The existence of a charged state can significantly affect the structure, stability, binding affinity and efficacy of biotherapeutic drugs. Antibody charge variants have attracted wide attention in the biotechnology industry due to their potential impact on stability and biological activity. Fine variations in the relative proportions of charge variants are often observed during conventional biological manufacturing or process changes, which pose a challenge in proving product comparability. Studies have shown that the different biological characteristics of mAb variants depend on changes in surface charges rather than structural changes of proteins. Therefore, it is necessary to understand the characteristics of drugs in order to identify charge variants and remove them when necessary. This can help determine the micro-heterogeneity that is critical to the quality of the product and further improve the development and production of therapeutic antibody products.

Fig.1 Charge variant analysis of mAbs using cation exchange chromatography. (Füssl, 2018)

Removal of Charge Variants Assay in Creative Biolabs

The presence of positively charged and negatively charged amino acids and negatively charged polysaccharides (sialic acid) means that large proteins exist as species with multiple charges, and some side effects can lead to changes in net charges. Understanding which amino acids or glycans are involved and their specific locations in large biotherapeutic proteins are crucial. Variations in the antibody-antigen binding region may have a more profound effect on function. Ion exchange chromatography (IEX) can separate some charge variants, especially those located on the surface of proteins rather than hidden inside the structure.

Speed and accuracy are key criteria for conducting charge change analysis in laboratories. At Creative Biolabs, we are committed to providing self-confident and fast analytical services to the biopharmaceutical and biomimetic industries. At present, we have the ability to provide a series of buffer, ion exchange or hydrophobic interaction chromatographic column chemical reagents and ultra-high-performance liquid chromatography (UHPLC) instruments to meet the needs of reliable analysis, separation and removal of charge variants in mAbs and therapeutic proteins.

Fig.1 Separation of the charge variants of papain digested Cetuximab by salt-gradient based IEX. (Fekete, 2015)

If you are interested in our services, please feel free to contact us for more details.

References

Füssl, F.; et al. Charge variant analysis of monoclonal antibodies using direct coupled pH gradient cation exchange chromatography to high-resolution native mass spectrometry. Analytical chemistry. 2018, 90(7): 4669-4676.
Fekete, S.; et al. Method development for the separation of monoclonal antibody charge variants in cation exchange chromatography, Part I: salt gradient approach. Journal of pharmaceutical and biomedical analysis. 2015, 102: 33-44.

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