Virus removal by filtration.

Advances in membrane technology have allowed the expansion of the size-exclusion removal principle to viruses of concern in the processing of pharmaceutical drug products derived from biological fluids and cell-culture techniques. Direct flow- and cross-flow filters are complementary techniques for virus removal and may be used either independently or as an adjunct to other virus clearance methods. Representative virus titre reduction data for microfiltration and ultrafiltration membranes are presented along with a validation model using bacteriophages as challenge viruses. Non-destructive filter integrity tests before and after filtration and a stringent process validation regime are applied to enhance product safety.