Viral clearance by virus-retentive filters is a crucial step in many biomanufacturing process streams, including production of monoclonal antibodies and cell culture media. Studies with model viruses or bacteriophage are needed to determine whether a specific filter should be categorized as a small or large virus retentive filter. In this study, viral retention and flowrates were compared between Meissner's 50 kDa and 500 kDa SepraPor® Hollow Fiber (HF) Ultrafiltration (UF) membranes used for Tangential Flow Filtration (TFF). These filters were challenged with ∼10 million plaque forming units (PFU) of the small bacteriophage ΦX174 suspended in deionized (DI) water. It was determined that the 50 kDa SepraPor® HF UF membranes gave log-reduction values (LRVs) ≥ 5 with flowrates ranging from 15.9 to 46.7 mL/min at 15 psi constant pressure. The 500 kDa SepraPor® HF UF membranes gave LRVs ≤ 0.74 with flowrates ranging from 8.8 to 286 mL/min. These results show that Meissner's 500 kDa SepraPor® filter membrane does not retain ΦX174 in water and does not function as a small virus retentive filter, while the 50 kDa SepraPor® filter membrane gives robust clearance of ΦX174 and can be categorized as a small virus retentive filter.
Bendiks et al. (Wed,) studied this question.