The Role of Moisture in Protein Stability

Abstract

The importance of water sorption on solid state stability of proteins can be addressed through an understanding of properties of the sorbed water and its impact on the properties of the protein. Most decomposition reactions are minimal at or below the monolayer level of hydration. Sorption of water beyond that of the monolayer generally results in increased rates of decomposition due to the increased conformational flexibility of the protein and the ability of the less tightly bound water to mobilize reactants. In many cases the rates of decomposition can be influenced by the addition of excipients. An understanding of how such excipients can influence water sorption and stability will allow for improved development strategies to minimize the decomposition of proteins in the solid state.