Glycation during storage and administration of monoclonal antibody formulations

Covalent modifications of therapeutic proteins are of interest for the biotech industry as they potentially impact the quality of the material. This study focuses on covalent protein modifications by the reducing monosaccharide glucose via the glycation reaction. In particular, we examined (i) to which extent different therapeutic monoclonal antibodies are glycated, (ii) the glycation during storage in sucrose-containing formulation buffers where non-reducing sucrose potentially could hydrolyze into its reducing constituent monosaccharides and (iii) the risk of glycation in the course of short-term incubation in Dextrose infusion bags in simulated administration testing. A boronate affinity chromatography method was employed to detect and quantify glycation products in different antibody formulations. For confirmation and to determine the degree of glycation per molecule, selected samples were analyzed via LC-ESI-MS. We could demonstrate that different antibodies differed drastically regarding the degree of glycation, probably a result of their respective fermentation conditions and protein glycation susceptibility. We also demonstrated that sucrose is a non-critical excipient with respect to glycation when stored long-term at intended storage conditions (2-8 degrees C). Finally, we could show that short-term incubation of antibodies in Dextrose infusion bags might lead to huMAb glycation, suggesting to test on glycated products when considering diluting protein drug products in infusion media containing reducing sugars.