Characterization of monoclonal antibodies using polymeric cation exchange monoliths in combination with salt and pH gradients

The characterization of three different mAb formulations of pharmaceutical interest is demonstrated using cation exchange polymethacrylate-based monolithic columns as well as imaged CE (iCE). Elution of the mAbs from both a strong cation exchanger (ProSwiftTM SCX-1S) and a weak cation exchanger (ProSwift WCX-1S) was readily achieved employing a linear salt gradient or a mixed buffer pH gradient indicating that either approach can be used in purification or isolation. Using a linear salt gradient, the elution profile on the two types of exchangers was found to differ indicating that the combination of both strong and weak ion exchangers is needed for complete characterization. The elution profile of two of the mAbs on the strong cation exchanger used in combination with a linear pH gradient from pH 4 to 10 showed signs of charge heterogeneity. The use of iCE was found to be the best choice for characterization of charge heterogeneity, showing a clear charge distribution for all three mAbs.