Purpose: To assess the effect of sugar molecules on solution viscosity at high protein concentrations.
Methods: A high throughput dynamic light scattering method was used to measure the viscosity of monoclonal antibody solutions. The effects of protein concentration, type of sugar molecule (trehalose, sucrose, sorbitol, glucose, fructose, xylose and galactose), temperature and ionic strength were evaluated. Differential scanning fluorimetry was used to reveal the effect of the same sugars on protein stability and to provide insight into the mechanism by which sugars increase viscosity.
Results: The addition of all seven types of sugar molecules studied result in a significant increase in viscosity of high concentration monoclonal antibody solutions. Similar effects of sugars were observed in the two mAbs examined; viscosity could be reduced by increasing the ionic strength or temperature. The effect by sugars was enhanced at higher protein concentrations.
Conclusions: Disaccharides have a greater effect on the solution viscosity at high protein concentrations compared to monosaccharides. The effect may be explained by commonly accepted mechanisms of interactions between sugar and protein molecules in solution.