Typical purification processes for monoclonal antibodies (mAb) consist of one or two polishing chromatography steps designed to remove product-related aggregates. In many cases, robust aggregate clearance can be achieved by cation exchange chromatography media. With this approach, monomer and aggregate species are separated based on net surface charge differences, where resolution can significantly depend on structural properties of the ion-exchange media. In this work, cation exchange chromatography was explored as a first-intent polishing step for a specific mAb that exhibited high aggregate levels post-Protein A chromatography. Experimental studies with both step and linear gradient elution resulted in insufficient aggregate clearance, indicating that separation of the impurity was not possible by surface charge alone. To further explore separation limits, accelerated degradation methods were developed to generate samples of typical process-related aggregate species. Biochemical analysis and complementary computational studies were performed to characterize these aggregate species. The use of bioanalytical techniques to identify strategies for minimizing process-related aggregation and optimizing the final aggregate clearance chromatography step will be discussed.

Biochemical and chromatographic characterization of aggregate species for downstream process development

245th National Meeting (2013)

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