Protein stability is known to be sensitive to interfacial stresses. While processing protein formulations, it is unavoidable that solutions will come into contact with an external interface of some kind. This exposure can occur through filtration, filling, or drying techniques. Biopharmaceutical products such as spray-dried powders and lyophilized cakes are usually along with high surface areas. Surface regions tend to have increased quantities of surface-active species, such as proteins or surfactants. Protein aggregation at interfaces frequently involves alterations in conformation, as proteins adjust their higherorder structure in reaction to interfacial pressures such as hydrophobicity, charge, and mechanical stress.