In the past decade, multimodal chromatography has been an area of active research, from both a fundamental perspective and with regards to process development applications. While much of the recent work has focused on multimodal cation exchange (MM CEX) chromatography, the increasing prevalence of non-mAb therapeutics as well as challenging mAb-aggregate separations motivates further development in the multimodal anion exchange (MM AEX) space. The objective of this work was to investigate multimodal anion exchange chromatography, with an eye towards potential applications for both mAb and non-mAb biologics. A library of novel MM AEX prototypes developed by Bio-Rad Laboratories was evaluated using linear salt gradient experiments with model proteins in bind and elute mode. Several of the resins showed unique selectivities compared to the commercially available Capto Adhere. Five of these resins were selected for further evaluation with three antibodies with diverse surface properties. In each resin system, the range of mAb adsorption behavior  (i.e. from flow through to fully retained) was classified at various pH conditions. The results of this screen then were used to identify optimal conditions at which to evaluate aggregate removal and recovery for industrial mAb-aggregate samples. This work suggests that a more diverse MM AEX ligand library could not only facilitate mAb-aggregate separations but could also enable MM AEX ligands to be used for finer resolution separations such as the removal of product related variants by expanding the pH operating range of this class of ligands. Expanding the MM AEX library could also potentially have important implications for the purification of non-mAb biologics, particularly low pI proteins, by providing new selectivities compared to the existing commercial resins.

Exploring the mulitmodal anion exchange space: Fundamental investigations and applications

255th National Meeting (2018)

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