Analytical QbD: development of a native gel electrophoresis method for measurement of monoclonal antibody aggregates

This paper presents a quality by design (QbD) based development of a novel native PAGE (N-PAGE) method as a low-cost analytical tool for analysis of aggregates of monoclonal antibodies. Comparability to the present gold standard of SEC has been established. The motivation is the fact that SEC requires relatively expensive equipment and consumables, thus making N-PAGE relevant to those academicians and other small companies involved in early-stage development of biotherapeutics that do not have access to SEC, especially in developing countries. Furthermore, SEC suffers from certain disadvantages including the possibility of secondary interactions between the stationary phase and analyte resulting in higher elution time and therefore underestimation of the analyte size. The proposed N-PAGE method can also serve as an orthogonal analytical method for aggregate analysis. A QbD-based approach has been used for development and optimization of the protocol. First, initial screening studies were carried out with parameters including the running buffer pH, running buffer molarity, gel buffer pH, loading dye, sample concentration, and running voltage. Next, optimization of operating parameters was performed using principles of design of experiments. The final optimized protocol was compared to the traditional SEC method and the results were found to be comparable. While N-PAGE has been in use for protein analysis for several decades, use of N-PAGE for analysis of mAb aggregates with data comparable to SEC such as the case presented here is novel.