Multimodal chromatography: Characterization of protein binding and selectivity enhancement through mobile phase modulators.

The unique selectivity of mixed mode chromatography resins is driving increasing utilization of these novel selectivities into bioprocess applications. There is a need for improved fundamental understanding of protein binding to these stationary phases to enable the development of efficient and robust purification processes. A panel of four monoclonal antibodies and two model proteins were employed to characterize protein interaction with a mixed-mode chromatographic resin comprising a hydrophobic ligand with cation-exchange functionality. Binding of these proteins was studied as a function of salt concentration and pH in the presence of various mobile phase modulators. This knowledge was applied towards screening mobile phase modulators that could selectively decrease host cell protein levels during monoclonal antibody purification.