Abstract
The ICH guideline Q14 on analytical procedure development underlines the importance of science and risk-based methods for the evaluation of the quality of medicines. Ultimately, a pharmaceutical company, the sponsor, is responsible that the analytical method is fit-for-purpose during routine use throughout its lifecycle. Part of the analytical procedure control strategy is the responsibility to assure availability of critical materials of the analytical method. For capillary zone electrophoresis (CZE) methods, the background electrolyte (BGE) composition is a key and critical material. In this study, we investigated whether key ingredients of the ε-aminocaproic acid (eACA) CZE (eACA-CZE) method for monoclonal antibodies can be replaced by structurally related chemicals. The complex heterogeneity patterns are compared, as well as the reportable results as the percentage main, acidic and basic peaks. Overall, the results underline the ruggedness of the eACA-CZE method and provide alternative options to eACA and triethyltetramine (TETA), in case there are quality or supply issues, thus de-risking and safeguarding release and stability studies for therapeutic mAbs.