Use of CE-SDS gel for characterization of monoclonal antibody hinge region clipping due to copper and high pH stress.

CE-SDS gel technique has been used extensively in the field of monoclonal antibody (mAb) as a tool for product purity, stability, and characterization. It offers many advantages over the traditional labor-intensive SDS-PAGE slab gel technology with respect to speed and resolution. Monoclonal antibodies are known to cleave in the hinge region due to extreme pH, high temperature and in the presence of metals, especially copper. This cleavage will impact the shelf lifetime of mAb product hence its quality. CESDS gel method using Beckman PA800 with UV detection is used to characterize the effects of copper and other metals such as iron and zinc on mAb clipping. In addition, mAb integrity under high temperature and high pH stress conditions was also evaluated and the results clearly show that CE-SDS gel can distinguish clipping due to copper versus heat and/or high pH. The data presented illustrate the power of this simple CESDS gel technique in supporting the development of mAb from product quality and stability to the final product characterization.