Polysorbate 20 prevents the precipitation of a monoclonal antibody during shear

Monoclonal antibodies (MAbs) are widely used as therapeutic proteins and they are frequently exposed to a high degree of stress during manufacturing or delivery. MAbs shear thin upon increasing shear rates. After undergoing multiple shear cycles, with a cone-and-plate rheometer, the solution viscosity of high concentration antibodies increases due to the formation of insoluble aggregates. These shear-induced insoluble aggregates do not form when polysorbate 20 is present in solution. We hypothesize that monoclonal antibodies form a thin protein layer at the air-water interface. MAbs at the interface expose their hydrophobic core to air leading to unfolding, multiple non-specific intermolecular interactions and, upon continuous high shear, precipitation. Surface tension analysis confirms that monoclonal antibodies are surface active and that polysorbate 20 can prevent their interaction with the air-water interface. In addition, we complement these findings with a viscometer that measures bulk viscosity without the influence of an air-liquid interfacial viscosity and find that the bulk viscosity increases slightly when Mab solutions contained polysorbate 20. These methods of analysis could be used when designing manufacturing systems in which a protein solution is subject to shear forces.