Virus inactivation in a factor VIII/VWF concentrate treated using a solvent/detergent procedure based on polysorbate 20

Treatment with solvent/detergent is a widely used method for ensuring the virus safety of plasma products. In the present study, virus inactivation by a novel solvent/detergent combination, i.e. TnBP (tri-n-butyl phosphate) and polysorbate 20 during the manufacture of the factor VIII/VWF concentrate Optivate® has been investigated. The inactivation of most enveloped viruses was rapid, i.e. >5 log in 2 min, although the inactivation of vaccinia virus was slower, i.e. 4 log in 1 h. Virus inactivation was effective over a wide range of conditions, i.e. solvent/detergent concentration, protein concentration and temperature, irrespective of whether tested individually or in combination. This confirms the effectiveness and robustness of this alternative version of the solvent/detergent procedure, and allows appropriate control limits to be set for this manufacturing step. Polysorbate 20 provides an alternative to the non-ionic detergents currently in use with the solvent/detergent procedure.