PT - JOURNAL ARTICLE AU - O'Donnell, Sean AU - Bolton, Glen TI - Proceedings of 2019 Viral Clearance Symposium, Session 6: Virus Retentive Filtration AID - 10.5731/pdajpst.2021.012682 DP - 2021 Jan 01 TA - PDA Journal of Pharmaceutical Science and Technology PG - pdajpst.2021.012682 4099 - http://journal.pda.org/content/early/2021/12/15/pdajpst.2021.012682.short 4100 - http://journal.pda.org/content/early/2021/12/15/pdajpst.2021.012682.full AB - Manufactures of therapeutic biological products are required to incorporate downstream unit operations that can inactivate or remove potential viral contaminants from the manufacturing process. The viral filtration unit operation is one of the most robust virus removal steps incorporated into downstream manufacturing processes. The primary virus removal mechanism is size exclusion by a network of nanopores in the viral filter membrane. Even though the mechanism of virus removal is sized based there are many operational parameters that can affect virus retention. This article summarizes the current understanding of the operation and validation parameters of this unit operation.