Protein A chromatography is widely used as the affinity capture step of both mAbs and Fc-fusion proteins because of its high degree of selectivity. Variations in elution behavior of the protein A capture step require more process development work and could have an impact on the polishing step in the downstream process. Thus, minimizing the variation in elution pH between different molecules for example, makes it easier to platform the capture process.
Amsphere A3 was designed so that differences in washing and elution buffers (type, conductivity and pH) have minor effects on the characteristics of the elution pool (pH, impurity levels, yield, etc). In this application note, the impact of the elution buffer counter-ion, pH and molarity were evaluated on the key purification performance parameters (HCP removal, yield, elution volume and pH of the elution pool) of Amsphere A3. In total, 5 different mAbs were used for the study.