Measuring Structural Changes as a Function of Protein Concentration using Infrared Spectroscopy

Many biopharmaceutical protein drugs are formulated at high protein concentrations. The high concentrations of these drugs alter their properties and increase their viscosities making them difficult to characterize. Infrared spectroscopy has long been used to deduce concentration and structural descriptions of proteins. We are developing new infrared methods to compare the structures, dynamics and functions of nearly identical biopharmaceutical protein samples. We have recently observed that infrared spectroscopy can be used to characterize both the structure of the protein as well as the associated water molecules. We will present our findings describing structural changes, induced by high concentration, in model polymers and proteins including the NIST reference monoclonal antibody.