Table III

Summary of Commercially Available Virus Filters

Filter Vendor	Filter Brand	Virus Target Class^{^a}	Mode^{^b}	Membrane Pore Symmetry	Layers	Membrane Chemistry
Millipore	Viresolve NFR	Retro	DFF	Asymmetric	Triple layer	Hydrophilic polyethersulfone (PES)
	Viresolve NFP	Parvo	DFF	Asymmetric	Triple layer	Hydrophilic polyvinylidene fluoride (PVDF)
	Viresolve 70	Parvo	TFF	Asymmetric	Single layer	Hydrophilic PVDF
	Viresolve 180	Retro	TFF	Asymmetric	Single layer	Hydrophilic PVDF
	Viresolve Pro	Parvo	DFF	Asymmetric	Double layer	Hydrophilic PES
Sartorius Stedim Biotech	Virosart CPV	Parvo	DFF	Symmetric	Double layer	Hydrophilic PES
Pall	Ultipor VF grade DV50	Retro	DFF	Symmetric	Triple layer	Hydrophilic acrylate-modified PVDF
	Ultipor VF grade DV20	Parvo	DFF	Symmetric	Double layer	Hydrophilic acrylate-modified PVDF
	Pegasus grade LV6	Retro	DFF	Symmetric	Double layer	Hydrophilic acrylate-modified PVDF
	Pegasus grade SV4	Parvo	DFF	Symmetric	Double layer	Hydrophilic acrylate-modified PVDF
Asahi Kasei	Planova 35N	Retro	DFF/TFF^{^c}	Asymmetric	Hollow fiber	Hydrophilic cuprammonium regenerated cellulose
	Planova 20N	Parvo	DFF/TFF	Asymmetric	Hollow fiber	Hydrophilic cuprammonium regenerated cellulose
	Planova 15N	Parvo	DFF/TFF	Asymmetric	Hollow fiber	Hydrophilic cuprammonium regenerated cellulose
	Planova BioEX	Parvo	DFF/TFF	Asymmetric	Hollow fiber	Modified PVDF

↵a “Target virus class” can be a subjective concept based on the application and product type (i.e. biotech vs plasma product). Some large virus retentive filters can retain viruses smaller than retroviruses. Consultation with filter vendors is warranted if clearance of a particular virus is a process requirement.
↵b DFF, direct flow filtration; TFF, tangential flow filtration.
↵c Can be configured by end users to run in either mode.
This material is reproduced with permission from John Wiley & Sons, Inc. Miesegaes, G.; Lute, S.; Aranha, H.; Brorson, K. Virus Retentive Filters. In Encyclopedia of Industrial Biotechnology, Flickinger, M. C. Ed.; John Wiley & Sons, Inc.: New York, 2009.