Overcoming Obstacles In Final Ultrafiltration Steps
By Nick Hutchinson, Market Development Manager
Cross flow filtration can be used in a range of applications within biopharmaceutical manufacturing processes. Microfiltration technology is incorporated into perfusion bioreactor operations for cell retention and can be used for harvesting bioreactors used to manufacture extracellularly-expressed products. In downstream operations ultrafiltration can play a significant role in concentrating intermediately purified product pools, thereby minimizing processing volumes. Ultrafiltration typically also plays a key role in enabling product to be diafiltered into solutions that permit subsequent chromatography operations to achieve maximumseparation performance.
Often a critical application for ultrafiltration is at the end of the purification process prior to final bulk filtration. At this stage excipients are typically added and the final product concentration specification as it will occur in the vial must be met. Given the importance of the end purification step it attracts surprisingly little attention in literature and yet it can present great challenges to bioprocess engineers.