Effective use of gamma irradiation for pathogen inactivation of monoclonal antibody preparations.

Gamma irradiation has been used for decades as an effective method of pathogen inactivation of relatively inert materials. Until recently, its application to biologicals has resulted in unacceptable losses in functional activity. In this report we demonstrate that the damaging secondary effects of gamma irradiation can be controlled while maintaining the pathogen inactivation properties due to damage by primary effects. Control is achieved by a combination of protection from free radical damage to a monoclonal antibody through the use of the antioxidant ascorbate and by freeze-drying to minimize the potential for generating free radicals. The data demonstrate a synergy of these two approaches that results in quantitative recovery of functional activity while maintaining the ability to inactivate greater than 5 logs of porcine parvovirus infectivity.