Antibody glycation during a Chinese hamster ovary 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. In the present study, we report kinetic studies of glycation formation of the model protein Adalimumab, relative to glucose and non-glycated protein in six Chinese hamster ovary (CHO) fed batch cultivations. We developed an in vivo model 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 either, suggesting that a reconsideration of the kinetic equation was necessary. With the introduction of a constraint using only the newly formed product (mAb_Δt ), the second-order reaction was successfully implemented. In addition, it is shown that the process knowledge derived from dynamic can be transferred to static experiments and vice versa. Hence, intensified design of experiments (iDoE) can be an applicable and useful tool in product quality studies in cell culture processes.