A high-throughput method for fast detecting unfolding of monoclonal antibodies on cation exchange resins

A fast method for assessing the stability of monoclonal antibodies (mAbs) adsorbed on ion exchange resins has been developed. The method exploited a real time polymerase chain reaction equipment to determine the temperature of protein phase transition, i.e., the so called melting temperature, based on differential scanning fluorimetry. Changes to the melting temperature were screened under various adsorption conditions and correlated with the protein stability upon adsorption. The method was tested for two different mAbs bound to various types of strong cation exchangers at different pH and loading concentrations. The mAbs destabilized upon adsorption due to strong binding, which manifested itself in aggregate formation and recovery reduction. The phenomenon depended on the resin type and binding conditions. However, regardless of the process conditions and resins used, drop in the melting temperatures to a critical value of about 30° could serve as an indicator of destructive changes in the protein structure in the adsorbed phase. The measurements were simultaneously accomplished for a number of samples with very small material consumption. Therefore, the method may be applied for screening resins and operating variables for a given mAb to exclude conditions that induce structure destabilization and aggregation.