Model-based development of an on-column PEGylation process

Abstract

Considering the high production cost of therapeutic proteins, post-translational modifications such as PEGylation have to be highly efficient and optimized so as not to waste the valuable protein to be modified. Among the different processes available, on-column PEGylation appears as an interesting alternative to the classical solution reaction for more selective synthesis of the targeted mono-PEGylated protein since it has the potential to restrict the coupling reaction to fewer reaction sites. In this work, the on-column PEGylation of α-lactalbumin using a strong anion-exchange resin is investigated. The influence of pH, reaction time, PEG to protein ratio and protein load is investigated. The on-column PEGylation process is shown to be more selective for lower degrees of PEGylation than the classical solution PEGylation reaction. Finally, the experimental results are described by a mathematical model in order to gain a more complete understanding of the mechanisms involved and develop a tool for process design and development.