Comparative analysis of the activity and content of different streptokinase preparations.

AIMS: The dosage of fibrinolytic agents such as streptokinase must be controlled carefully to maximize therapeutic activity while avoiding adverse effects. Therefore, the integrity and activity of streptokinase products is likely to be clinically relevant. This study was conducted to compare the in vitro characteristics of different streptokinase preparations. METHODS AND RESULTS: Sixteen streptokinase preparations (three of which were recombinant) were compared in a chromogenic substrate activity assay by native, and reducing, sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis (PAGE), and N-terminal sequencing. Deficiencies in streptokinase activity were observed in most of the products: only three fulfilled the minimum requirements of the European Pharmacopoeia. These were Icikinase (ICI Pharm Ltd, India, only one of two batches tested), Kabikinase (Pharmacia Upjohn, Sweden), and Streptase (Aventis Behring GmbH, Germany). The remaining products exhibited activities ranging from 20.8 to 86.6% of the label claim. Differences in composition and purity were demonstrated by both native and reducing SDS-PAGE. N-terminal sequencing of the recombinant preparations showed differences compared with the native protein--indeed, for one product, the 15 N-terminal amino acids bore no resemblance to streptokinase. CONCLUSION: There are wide variations in the activity, purity, and composition of the available streptokinase preparations.     

Characterization of factor VIII/von Willebrand factor concentrates using a modified method of von Willebrand factor multimer analysis

In order to provide patients with von Willebrand disease a factor VIII (FVIII)/von Willebrand factor (vWF) concentrate of reproducible quality, an SDS-agarose gel electrophoresis method has been established to determine the content of the high molecular weight multimers (band 11 and higher) of vWF. This method has been used to characterize the content of high molecular weight vWF multimers in Humate^® P/Haemate^® P, a commercial FVIII/vWF concentrate. The average content of high molecular weight vWF multimers of 47 batches of Humate^® P/Haemate^® P has been determined to be 84.1% of the corresponding bands in normal human plasma. Use of this multimer analysis method for the characterization of five further commercial products revealed clear differences with respect to the high molecular weight vWF multimer content. Furthermore, there is a linear correlation ( r ² = 0.73) between the content of high molecular weight vWF multimers and the specific activity of vWF (determined as vWF:RCoF/vWF:Ag). The method described here for analysis of the content of high molecular weight vWF multimers is a reliable and reproducible method to characterize this class of factor concentrates with respect to vWF multimer composition.