Virus retention by a hydrophilic triple-layer PVDF microporous membrane filter.

Retention of bacteriophages (phi 6, PR772, T1, and PP7) and mammalian viruses (poliovirus and influenza A virus) by a hydrophilic triple layer PVDF microporous membrane, the Ultipor VF grade DV50 membrane, was evaluated. Challenges of membrane discs or pleated filter cartridges were performed at concentrations of 10(6)-10(8) PFU/mL in one or more of the following carrier fluids: water, saline, gelatin (0.1%) in phosphate buffer, Dulbecco's Modified Eagle Medium (MEM), and MEM supplemented with 10% fetal bovine serum (MEM + 10). The data demonstrate a minimum log titer reduction (LTR) of 6 for viruses larger than 50 nm irrespective of the carrier fluid. Protein transmission levels of greater than 95% for IgG and albumin were achieved. For integral pleated filter cartridges, correlation between a nondestructive integrity test (using the forward flow integrity test method) and virus retention was demonstrated. The Ultipor VF grade DV50 filter can be applicable in the manufacture of biologicals and biopharmaceuticals, where high protein transmission and consistent viral titer reduction are desired.