Yamamoto C H, Pinto T J
Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Brazil.
J AOAC Int. 1996 Mar-Apr;79(2):434-440.
The standard, quantitative determination of neomycin activity by the agar diffusion method requires an 18 to 24 h incubation time. To reduce incubation time, an alternative method using triphenyltetrazolium chloride has been developed. The inhibition zone appears much earlier; hence, an effort was made to standardize it. This indicator develops a physical response, related to the biological one, after a determined period. A Staphylococcus epidermidis suspension inoculated into solid medium at a concentration low enough that growth is not visible can reduce the dye to formazan. There is enough contrast to read the inhibition zone optically after a 7 h incubation. There is no significant difference between standard curves for 7 and 24 h incubations. Comparative assays for some pharmaceutical drugs containing neomycin in different forms show that it is possible to reduce incubation time. This modification is valid because no dispersion of results was detected by statistical analysis, which indicates that they belong to the same population. Thus, a rapid microbiological assay of neomycin has been validated and standardized.
通过琼脂扩散法对新霉素活性进行标准定量测定需要18至24小时的孵育时间。为了缩短孵育时间，已开发出一种使用氯化三苯基四氮唑的替代方法。抑菌圈出现得要早得多；因此，人们努力对其进行标准化。该指示剂在一段确定的时间后会产生与生物学反应相关的物理反应。将表皮葡萄球菌悬浮液以足够低的浓度接种到固体培养基中，使其生长不可见，该悬浮液可将染料还原为甲臜。孵育7小时后，有足够的对比度以光学方式读取抑菌圈。7小时和24小时孵育的标准曲线之间没有显著差异。对一些含有不同形式新霉素的药物进行的比较测定表明，可以缩短孵育时间。这种改进是有效的，因为通过统计分析未检测到结果的离散，这表明它们属于同一总体。因此，新霉素的快速微生物测定法已得到验证和标准化。
