Lightbown J W, Bond J M, Mussett M V, Tackett L L
Bull World Health Organ. 1972;47(5):635-40.
As supplies of the International Standard for Chlortetracycline were practically exhausted, it was replaced. The potency of the second international standard was defined on the basis of an international collaborative assay comprising 157 individual assays performed in 9 laboratories in 6 countries. The mean potencies obtained in the participating laboratories, although they varied by only 7%, were heterogeneous. However, the mean potency for all the laboratories combined did not differ significantly from that of the first international standard. The International Unit for chlortetracycline was therefore defined as the activity contained in 0.001 mg of the second international standard, corresponding to a potency of 1 000 IU/mg.
由于金霉素国际标准品的供应几乎耗尽，它被替换了。第二个国际标准品的效价是基于一项国际协作测定确定的，该测定包括在6个国家的9个实验室进行的157次单独测定。参与实验室获得的平均效价虽然仅相差7%，但存在异质性。然而，所有实验室合并后的平均效价与第一个国际标准品的平均效价没有显著差异。因此，金霉素的国际单位被定义为0.001毫克第二个国际标准品中所含的活性，相当于效价为1000 IU/mg。
