Controlled gamma-irradiation mediated pathogen inactivation of human urokinase preparations with significant recovery of enzymatic activity

Human sources of urokinase have led to the contamination of in-process lots of commercially available material with human pathogens. Effective pathogen inactivation of urokinase preparations can be achieved through the use of γ-irradiation. Additionally, the presence of a free radical scavenger (ascorbate) and the control of temperature have resulted in maintenance of the enzymatic activity of urokinase without a significant effect on the pathogen inactivation properties of γ-irradiation. In this study we have optimized the conditions during γ-irradiation to achieve inactivation of porcine parvovirus by 5 logs and vaccinia virus to levels below the limits of detection, while maintaining 92% of urokinase activity. Product specific optimization of γ-irradiation has the potential to provide effective pathogen inactivation while maintaining substantial functional activity for many therapeutic proteins.