A consensus rating method for small virus-retentive filters. II. Method evaluation

Virus filters are membrane-based devices that remove large viruses (e.g., retroviruses) and/or small viruses (e.g., parvoviruses) from products by a size exclusion mechanism. In 2002, the Parenteral Drug Association (PDA) organized the PDA Virus Filter Task Force to develop a common nomenclature and a standardized test method for classifying and identifying viral-retentive filters. A test method based on bacteriophage PP7 retention was chosen based on developmental studies. The detailed final consensus filter method is published in the 2008 update of PDA Technical Report 41: Virus Filtration. Here, we evaluate the method and find it to be acceptable for testing scaled-down models of small virus-retentive filters from four manufacturers. Three consecutive lots of five filter types were tested (Pegasus SV4, Viresolve NFP, Planova 20N and 15N, Virosart CPV). Each passed the criteria specified in the test method (i.e., >4 log10 PP7 retention, >90% intravenous immunoglobulin passage, and passing integrity/installation testing) and was classified as PP7-LRV4.