Streamlining cation exchange chromatography process development for therapeutic monoclonal antibody purification

Cation exchange (CEX) chromatography plays a critical role in impurity clearance, notably in removing high molecular weight (HMW) species for therapeutic monoclonal antibody (mAb) purification. CEX is well-known for its selectivity and scalability as a polishing step. To develop more efficient and productive processes, five commercially available CEX resins (Capto S ImpAct, Poros 50 HS, Poros XS, Nuvia HR-S, and Eshmuno CPX) were evaluated using three mAbs, in order to identify optimal resins and to develop a process with superior DBC, impurity clearance, yield, and robustness. Initial pressure flow curve experiments examined operating velocity, and DBC studies determined column loading capacity. Linear salt gradient and screening studies employing high-throughput technology optimized column elution conditions. A systematic design of experiments (DOE) approach further characterized the process robustness. One superior CEX resin was identified, Poros XS, that excelled in binding capacity and robustness along with two comparable resins, Capto S ImpAct and Eshmuno CPX. In addition, a mechanistic model-based process development approach was used as a proof-of-concept for industry application with < 2 % deviation from experimental results. This study established a streamlined methodology for resin selection and CEX chromatography process development. Poros XS was chosen as the leading resin as it can be operated at high flow rates and a residence time of 3 min, high binding capacities with DBC_{10 %} values over 100 g/L at low pH and conductivity, effectively reduces HMW species from 5 % to 1 %, and maintains over 90 % yield with acceptable robustness across all three mAb molecules.