Antibody glycation during a CHO fed-batch process is following a constrained second order reaction
Glycation on lysine side chains of recombinant monoclonal antibodies (mAb) is a well known phenomenon in manufacturing processes of biopharmaceuticals that potentially alter the efficacy of the therapeutic protein. Previously, we reported a method to quantify the level of glycation formation directly from cell culture supernatants using boronate affinity chromatography (BAC). In this study, we report kinetic studies of glycation formation of the model protein Adalimumab, related to glucose and non-glycated protein in six CHO fed batch cultivations. An in-vivo model was demonstrated from glycation kinetic studies that is capable of estimating the reaction rate constant in static and dynamic bioprocesses, respectively. As anticipated, pseudo first order reactions with respect to present glucose concentration or non-glycated mAb were not sufficient to describe the glycation formation during the bioprocesses. However, second order reactions did not reveal linear relationship of glycated mAb to the product of glucose and non-glycated mAb, suggesting a reconsideration of kinetic equation. With the introduction of a constraint using only the newly formed product, i.e., the nascent protein, the second-order reaction was successfully implemented. These results show that the process knowledge derived from dynamic can be transferred to static experiments and vice versa. Hence, intensified DoE can be an applicable and useful tool in product quality studies in cell culture processes.