Formulating high-concentration biopharmaceuticals presents unique challenges due to the increased viscosity caused by protein self assembly, which impacts manufacturing, stability, and injectability. This study investigates specifically the impact of electrostatic interactions on the aggregation behavior and rheology evolution of a biotherapeutic monoclonal antibody. The temperature-driven aggregation mechanism of a monoclonal antibody (mAb) formulation is analyzed, highlighting variations in aggregation behavior with the addition of monovalent and bivalent salts. The effects of pH on aggregation are also systematically explored. Viscosity measurements were conducted using the microfluidic piezoelectric sensor device, NanovisQ, while aggregation mechanisms were examined through diffusing wave spectroscopy (DWS). Both methods require minimal sample quantities, making them ideal for early-stage drug development. This research highlights the critical role of formulation variables in regulating protein-protein interactions, paving the way for the development of stable and highly concentrated monoclonal antibody biopharmaceuticals.
