Lightbown J W, Kogut M, Uemura K, Grab B
Bull World Health Organ. 1966;34(3):429-35.
The National Institute for Medical Research, London, was requested by the WHO Expert Committee on Biological Standardization to establish a second International Standard for Dihydrostreptomycin, since stocks of the first International Standard were depleted. A batch of 500 g of dihydrostreptomycin sulfate obtained in 1961 was distributed into ampoules in 200-mg amounts and dried in vacuo; the ampoules were then filled with dried nitrogen and sealed. The proposed replacement material has been assayed biologically in terms of the first International Standard in seven laboratories in six countries by means of both plate-diffusion and turbidimetric assays.Significant heterogeneity of the potencies obtained by the different laboratories was revealed by statistical analysis; this heterogeneity might be caused by slight differences in the content of streptomycin of the two samples. The material has been established as the Second International Standard for Dihydrostreptomycin with a defined potency of 820 IU/mg. The International Unit of Dihydrostreptomycin is defined as the activity of 0.001219 mg of the Second International Standard for Dihydrostreptomycin.
由于第一批国际标准品的库存已耗尽，世界卫生组织生物标准化专家委员会要求伦敦的国家医学研究所建立第二个双氢链霉素国际标准品。1961年获得的一批500克硫酸双氢链霉素被分装成每安瓿200毫克，并进行真空干燥；然后向安瓿中充入干燥氮气并密封。提议的替代材料已在六个国家的七个实验室中，通过平板扩散法和比浊法，按照第一个国际标准品进行了生物学测定。统计分析显示，不同实验室获得的效价存在显著异质性；这种异质性可能是由于两个样品中链霉素含量的细微差异所致。该材料已被确立为双氢链霉素第二个国际标准品，规定效价为820国际单位/毫克。双氢链霉素国际单位定义为0.001219毫克双氢链霉素第二个国际标准品的活性。
