Fast and high-resolution purification of a PEGylated protein using a z² laterally-fed membrane chromatography device

PEGylated proteins comprise a class of value-added biopharmaceuticals. High-resolution separation techniques are required for the purification of these molecules. In this study, we discuss the application of a newly developed z² laterally-fed membrane chromatography (or z²LFMC) device for carrying out high-resolution purification of a PEGylated protein drug. The device used in the current study contained a stack of anion exchange (Q) membranes. The membrane bed-height of this z²LFMC device being small, it could be operated at very high flow rates, at relatively low back pressures. The primary goal was to speedily and efficiently separate a mono-PEGylated protein from impurities present in the PEGylation reaction mixture. A resin-based anion exchange column having the same ligand and bed-volume was used as the control device. The purification performance of the z²LFMC device and the control column were compared terms of resolution, recovery and purity. The z²LFMC device outperformed the control column in terms of every metric compared in this study. Higher purity (85.4% as opposed to 77.9%) and higher recovery (28% greater) of the target mono-PEGylated protein were obtained using the z²LFMC device at 20-time higher speed. These results clearly demonstrate that the z²LFMC device could be a faster and more efficient alternative to resin-based columns for purification of biopharmaceuticals.