Abstract: Apramycin was diluted to different concentrations and was added to bacterium suspension which is made of Staphylococcus aureus and antibiotics standardization medium Ⅲ. After cultivated for 3 to 4 h at 37 ℃, the linearity of the dose-response relationship was analysised. The accuracy of developing turbidimetric method was checked. At the concentration range from 2.9 to 7.2 U/mL, log values of concentrations of apramycin were linear correlation with corresponding opacities, which correlation coefficient was r=0.9988. By the t-test, regression effect of log values of concentrations of apramycin with corresponding opacities was significant. Average recovery is 99.82%, and average confidence rate is 2.48%, and relative standard deviation is 1.86%. Potencies were unitied which determined by turbidimetric method and cylinder-plate method. Turbidimetric method has low confidence rate, high sensitivity, high precision,so that can be used to determine apramycin and apramycin peprations.

Key words: turbidimetric method; cylinder-plate method; apramycin; potency