Frontal chromatography purification of monoclonal antibodies with high loadings using a cation exchange hydrogel membrane

The application of frontal chromatography with cation exchange (CEX) resins to the downstream polishing of therapeutic monoclonal antibodies (mAbs) enables the selective removal of impurities, such as mAb aggregates and host cell proteins, with very high loadings relative to bind and elute processes. However, using CEX resins for frontal chromatography requires long loading times that are challenging to implement into manufacturing processes. CEX membranes can substantially reduce these long loading times because they bind proteins by a convective mechanism and thus can be operated at much higher flow rates. However, until recently commercially available CEX membranes have had considerably lower capacities for mAbs relative to CEX resins, limiting their possible loadings during frontal chromatography processes. This study demonstrates the advantages of a high ionic density hydrogel CEX membrane that has significantly higher capacities for mAbs. It was found that the CEX hydrogel membrane in frontal chromatography mode was effective for the removal of aggregates from four mAb feeds up to a loading of 1,000 g/L, which was notably higher than what was possible with two lower-capacity commercially available CEX membranes. Finally, it was demonstrated that the CEX hydrogel membrane operating in frontal chromatography mode could be cycled 35 times over 20 hrs with a consistent monomer recovery and impurity removal (mAb aggregates, host cell proteins).