RESUMO
A highly purified plasminogen concentrate, LYS-PLASMINOGEN Steam Treated, has been developed for thrombolytic therapy of arterial and venous occlusions in combination with fibrinolytic agents. In search of a highly efficient drug covering this indication, we decided to select the lys-form of plasminogen because of its higher affinity to fibrin in contrast to the glu-form. This property of lys-plasminogen also led us to expect an improved thrombolytic activity as opposed to other forms of the proenzyme. The intermediate product is manufactured from pooled human citrated plasma by ethanol fractionation after separation of coagulation factor proteins. Further processing includes specific transformation and purification steps. The final product is a freeze-dried preparation characterized by a high specific activity greater than or equal to 18.0 CU/mg protein and a content of lys-plasminogen of greater than or equal to 95%. To reduce the risk of viral infections, the plasma pool includes only plasma donations which are ALT tested and negative for HBsAg and anti-HIV. In addition the intermediate freeze-dried bulk powder is subjected to a virus inactivation procedure based on steam treatment for 10 hours under standardized product specific conditions without using special protein stabilizers. Physical parameters of steam treatment provide for a maximum virus killing effect without impairing the biological plasminogen activity or changing the molecular integrity of the product. In a preclinical test HIV was inactivated by 6 log 10 after 3 hours of steam treatment leaving a 7 hour safety margin for inactivation of more heat resistant viruses.(ABSTRACT TRUNCATED AT 250 WORDS)
