Assessing the impact of sanitization methods for regenerated cellulose ultrafiltration/diafiltration membrane on membrane integrity and protein quality

Ultrafiltration/diafiltration (UF/DF) is typically the final step in downstream processing of recombinant monoclonal antibody (mAb) products, which serves for protein concentration and buffer exchange. For UF/DF membranes composed of regenerated cellulose (RC), sanitization with 0.1 M sodium hydroxide is generally recommended by the supplier, but it may not be sufficient for reducing bioburden during large scale manufacturing. Therefore, more stringent sanitization methods for RC membranes are required. However, chemicals used in such sanitization step may disrupt membrane integrity, while the corresponding residuals may reduce product quality. Previous work has shown that high concentration of sodium hydroxide or addition of peracetic acid (PAA) can effectively reduce bioburden, but their effects on the RC membranes remain unknown. In this work, we assessed the impact of two sanitization methods, 0.5 M sodium hydroxide and 30 mM PAA in combination with 0.5 M sodium hydroxide, on membrane integrity and protein quality of Millipore and pall corporation (PALL) membranes. Both methods showed a similar impact as the control after performing 15 cycles. However, the addition of PAA may cause residual chemical concerns, therefore, 0.5 M sodium hydroxide was recommended as an effective and safe sanitization method for RC UF/DF membranes.