International collaborative study to establish the 3rd International Standard for Streptokinase

Abstract

Summary. An international collaborative study was organized to calibrate a replacement for the current (2nd) International Standard (IS) for Streptokinase, stocks of which are almost exhausted. Two candidate preparations were assayed against the 2nd IS in a study involving 16 laboratories in 12 countries: preparation 88/824 (coded B), and preparation 00/464 (C and D, coded duplicates). Laboratories could use two methods provided, either a fibrin clot lysis assay or a solution chromogenic method, or an in-house method. Laboratories were encouraged to perform more than one method if possible. With the exception of one laboratory which gave outlying results for preparation 00/464, there was good agreement within and between laboratories and no significant differences between potencies using the different methods employed. This study demonstrates that a solution chromogenic assay is an acceptable format for potency determination of the streptokinase preparations in this study and fibrin is not necessary. It has now been agreed that a solution chromogenic plasminogen activation assay replace the current euglobulin reference method for streptokinase activity determination in the European Pharmacopoeia. Study participants, SSC of the International Society on Thrombosis and Haemostasis and the Expert Committee on Biological Standardization (ECBS) at the World Health Organization approved preparation 00/464 (C,D in the study) as the 3rd IS for Streptokinase with a potency of 1030 IU per ampoule.

Constitutive Expression and Optimization of Nutrients for Streptokinase Production by Pichia pastoris Using Statistical Methods

“…Plasminogen Activation Assay [24] ChromogenicS-2251 substrate was used in quantification of SK plasminogen activation. Briefly human plasminogen was activated with SK at 37°C for 15 min and the formation of plasmin mediated by streptokinase was measured by its hydrolysis of the chromogenic H-D-Val-Leu-Lys-pNA substrate S-2251.…”

Biosimilars: the process is the product. The example of recombinant streptokinase

“…Potency estimates obtained for rSK (Fig. (A) left panel) were consistent with native streptokinase, whereby the presence of fibrin had no significant effect on activity . When rSK‐Met was compared in the same three assay systems (Fig.…”

Validation of the Chromogenic Bioassay for the Potency Assessment of Streptokinase in Biopharmaceutical Formulations

“…The validated SCSA was applied to the potency assessment of streptokinase in biopharmaceutical products, giving values within 92.20 and 108.97% of the stated potency, as shown in Table 4, meeting the specifications which claim 90-110% of the stated potency [8]. In addition, as the production of STK can be accompanied by the formation of streptodornase, the activity was assessed by the in vitro assay, giving results lower than 9.79 IU per 100 000 IU of STK, as demonstrated in Table 5.…”

“…It was demonstrated that the chromogenic substrate assay (SCSA), due to its ability to activate the fibrinolytic system, converting plasminogen to plasmin, is a suitable procedure for the potency determination of the streptokinase preparations [8,9].…”