Charge Variant Analysis
Charge variants of a biological product can have implications on stability and biological function. Charge heterogeneity can be caused by sequence variants (e.g. C-terminal lysine clipping), chemical degradation products (e.g. deamidation) and some post-translational modification (e.g. glycans containing sialic acid). Variability can be inherently characteristic of the host cell line, or can be introduced by commercial manufacturing methods. Understanding and managing this heterogeneity is implicit in the requirements of ICH Q6b.
Ion Exchange Chromatography
Using chromatographic methods, proteins can be separated according to their overall net charge, based on the isoelectric point (pI). Ion Exchange Chromatography is a powerful technique which can distinguish between molecules that have minor differences in the net charge. Due to the amphoteric properties of several amino acid side chains, this characteristic is fundamental to understanding heterogeneity of the biologic.In efforts to prove biosimilarity, side by side analysis of the biosimilar material to a reference product can help highlight characteristics requiring further investigation.
Contact our scientists today to discuss your charge variant analysis requirements.