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Phage passage after extended processing in small-virus-retentive filters.
Scott Lute1, Mark Bailey, Jessica Combs
1Division of Monoclonal Antibodies, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA.
Biotechnology and Applied Biochemistry
|February 9, 2007
Summary
Small phages like PhiX-174 and pp7 can model mammalian viruses for testing virus-retentive filters. Their similar retention across filter brands validates their use in evaluating filter performance.
Area of Science:
- Biotechnology
- Filtration Technology
- Virology
Background:
- Direct-flow, small-virus-retentive filters are critical for biopharmaceutical manufacturing.
- Evaluating the efficacy of these filters against small viruses is essential for process validation.
Purpose of the Study:
- To assess the retention capabilities of four different small-virus-retentive filter brands using two small bacteriophages.
- To determine the suitability of PhiX-174 and pp7 bacteriophages as surrogates for small mammalian viruses in filter performance testing.
Main Methods:
- Commercial process fluid was challenged with PhiX-174 and pp7 bacteriophages.
- Phage passage, flux, and log reduction values (LRV) were measured across Viresolve NFP, Virosart CPV, Ultipor DV20, and Planova 20N filters.
- Filter performance was analyzed under overloaded conditions and in relation to cumulative phage load.
Main Results:
- All tested filters exhibited some phage passage, particularly under overloaded conditions.
- Clearance of pp7 and PhiX-174 was comparable for each filter brand, indicating their equivalence for testing.
- Flux patterns and instantaneous log reduction values varied between filter brands, highlighting unique performance attributes.
Conclusions:
- PhiX-174 and pp7 bacteriophages serve as effective and equivalent models for evaluating small-virus-retentive filters.
- Phage-based validation offers a robust and attractive alternative to current methods for assessing filter performance against small viruses.
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