In order to evaluate the fibrinolytic activities of 3 kinds of urokinase preparation, the fibrinplate, fibrin-tube and modified Chandler's loop method developed by us were compared.
1) The modified Chandler's loop method was found to be most sensitive and physiological of the 3 assay methods.
2) Preparations A and B, consisting mainly of high molecular weight of 54, 000 daltons showed satisfactorily high value by the 3 assays, but preparation C with low molecular weight of 33, 000 daltons showed relatively lower activity by the modified Chandler's loop method. These results support the validity of Lormeau's theory (1978).
3) Three kinds of urokinase preparation were stable when they were dissolved in buffer solution at pH 7.2 at room temperature for several hours.
