A Collaborative Study Designed to Establish the 4th International Standard for Heparin

Summary

An international collaborative study, in which 22 laboratories participated, was carried out to establish a replacement for the International Standard for Heparin. A total of 248 assays were analyzed, including APTT, thrombin inhibition and anti-Xa assays, as well as pharmacopoeial assays. Overall, there was less than 5% difference in the mean potency estimates of the candidate preparations, by all assay methods. The freeze-dried preparation 82/502 demonstrated the closest parallelism by bioassay to the existing standard and was established by WHO as the 4th International Standard for Heparin, with an assigned unitage of 1780 i.u. per ampoule.

Keywords

Heparin - Standard

• References

• 1 Bangham DR, Woodward PM. A collaborative study of heparins from different sources. Bull WHO 1970; 42: 129-149
• 2 Brozovic M, Bangham DR. Standards for heparin. In: Heparin - Structure, Function and Clinical Implications. Bradshaw RA, Wessler S. (eds.) Plenium Press; New York - London: 1975. p 163
• 3 Finney DJ. Statistical Method in Biological Assay. 3. edition Griffin & Co.; London: 1978
• 4 United States Pharmacopeia. Twentieth Revision. 1980 p 365
• 5 Bliss CJ. The Statistics of Bioassay with Special Reference to the Vitamins. Academic Press Inc.; New York: 1952
• 6 Kirkwood TB L. Geometric means and measures of dispersion. Biometrics 1979; 35: 908-909
• 7 Pharmacopeial Forum, USP. 1984 p 3873
• 8 Bull Health Organization, League of Nations. 1943-44. 10. 02 151
• 9 WHO, Technical Report Series. No. 700 1984; p 18