Lightbown J W, Thomas A H, Grab B, Outschoorn A S
Bull World Health Organ. 1973;48(1):85-90.
Since supplies of the first International Standard for Polymyxin B were exhausted, it was replaced by a second international standard the potency of which was estimated from the results of a collaborative assay carried out by 5 laboratories in 4 countries. The wide variations in the results probably resulted from difficulties experienced in handling the first international standard. The potency finally agreed upon by the collaborating laboratories, on the basis of the overall mean values obtained after rejection of the most discrepant assays, was 8 403 IU/mg. That value was accepted by the WHO Expert Committee on Biological Standardization (1970), which consequently defined the International Unit of polymyxin B as the activity contained in 0.000119 mg of the second international standard.
由于首批多粘菌素B国际标准品的供应已耗尽，它被第二个国际标准品所取代，其效价是根据4个国家的5个实验室开展的协作测定结果估算得出的。结果差异很大，可能是因为在处理首批国际标准品时遇到了困难。合作实验室根据剔除差异最大的测定结果后得到的总体平均值，最终商定的效价为8403 IU/mg。该值被世界卫生组织生物标准化专家委员会（1970年）接受，因此将多粘菌素B的国际单位定义为0.000119 mg第二个国际标准品所含的活性。
