pH–conductivity hybrid gradient cation-exchange chromatography for process-scale monoclonal antibody purification

The commercial production of recombinant human monoclonal antibody therapeutics demands robust processes. In this article we describe the development of a pH–conductivity hybrid gradient for a cation-exchange chromatography step to obtain high binding capacity and consistent purification resolution in scale process. Operational parameters and their ranges were characterized with DOE statistical method. Aggregate, DNA and leached protein A removal were examined during development. The advantages and disadvantages of hybrid gradient elution compared to sodium chloride gradient elution were explored. As this step was designed as a good fit for the compatibility of the feed and operating pH/conductivity conditions for next step, the effects of elution by either changing sodium chloride concentration or changing pH of elution buffers on overall separation efficiency were compared. The operation condition was further confirmed in six 2000 L scale runs. The thorough evaluation demonstrated process reliability of hybrid gradient cation-exchange chromatography with high step purity and yield.