Evaluation of the Performance of Commercial Virus Filters in Biopharmaceutical Downstream Processes

Virus filtration in downstream biopharmaceutical processes is used to remove undesired viral particles from monoclonal antibodies or therapeutic proteins. It is a size-based removal process in which the virus is captured in the virus retentive region of the filter, and the product is transmitted through the filter. Virus filtration is often challenged by size similarity between the target virus and product, causing undesired virus breakthrough or protein retention (protein fouling) at the virus retentive site. Here, seven different membranes which composed of commercial virus filters were evaluated in terms of the filtrate flux and virus removal performance under the same feed solution conditions. Unique morphologies and surface properties of membranes were examined using scanning electron microscopy, X-ray photoelectron spectroscopy, and contact angle analysis. The surface properties showed no significant impact on the virus filtration performance, and the unique pore morphology of each membrane showed varied filtrate flux behavior. Not only the physical properties of virus filters but also feed solution conditions such as protein concentration and the type of model virus altered virus removal performance, indicating the need to choose appropriate feed solution conditions and model viruses for accurate validation of commercial virus filters.