Chemical and Physical Characterization of Therapeutic Proteins in Solution and Amorphous Solids

Abstract

The chemical and physical stability of proteins in solution and solids was addressed in this dissertation. Protein-excipient interactions in lyophilized solids were studied by hydrogen/deuterium exchange with mass spectrometry (chapter 3) while glycosylation quanitification (chapter 4) and deamidation (chapter 5) was characterized in antibodies in solution. LC/ESI-MS was the method of choice for all studies. Hydrogen/deuterium exchange study showed that the method can be used to obtain region specific information about protein-excipient interactions in solids. It was demonstrated that exchange protection did not occur uniformly along the backbone of the protein and was dependant on excipient type and protein structure. The glycosylation quanitification study demonstrated that the Fc/2 (limited proteolysis followed by reduction) method was relatively quick and accurate and showed comparable values to the standard sugar release assay. Antibody deamidation study demonstrated that secondary structure played a pivotal role in determination of the deamidation products in antibodies.