Thromb Haemost 1993; 69(05): 430-435
DOI: 10.1055/s-0038-1651628
Original Article
Coagulation
Schattauer GmbH Stuttgart

An International Collaborative Study to Investigate Standardisation of Hirudin Potency

Colin Longstaff
The National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, UK
,
Man-Yu Wong
The National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, UK
,
Patrick J Gaffney
The National Institute for Biological Standards and Control, Potters Bar, Hertfordshire, UK
› Institutsangaben
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Publikationsverlauf

Received 29. Oktober 1992

Accepted after revision 14. Januar 1993

Publikationsdatum:
25. Juli 2018 (online)

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Summary

An international collaborative study has been carried out to investigate the reproducibility of hirudin assays in 13 laboratories using four recombinant hirudins and one natural, sulphated product. A simple assay procedure was proposed involving the titration of α-thrombin with inhibitor and measurement of residual activity using a chromogenic substrate. A standard α-thrombin preparation was supplied to ensure that this reagent was of uniform quality throughout the study. The method appeared to present no difficulties and laboratories reported similar potencies for the 5 hirudin samples, in line with expected values. This gave 200–222 Thrombin Inhibitory Units/ampoule (TIU/ampoule) of lyophilised hirudin, with geometric coefficient of variation (gcv) values ranging from 10.15–15.97%. This corresponds to specific activities of approximately 14,300–15,900 TIU/mg protein. This is close to the upper limit of previously reported values of specific activity. We conclude that the precision of this determination compared with the wider range of values in the literature (8,000–16,000 thrombin inhibitory units [TIU]/mg) results from the use of good quality standard α-thrombin by all laboratories. This study has important implications for hirudin standardisation.