Method for preparing netilmicin sulfate freeze-dried powder injection

The invention provides a method for preparing a netilmicin sulfate freeze-dried powder injection. The method comprises the following steps: (a) mixing netilmicin sulfate, an antioxidant, an excipient and first injection water, sequentially performing pH value adjustment and adsorption treatment to obtain a mixed solution A; and (b) mixing the mixed solution A and second injection water in a mass ratio of 8:(1-3), and sequentially performing freezing treatment and drying treatment to obtain the netilmicin sulfate freeze-dried powder injection. Compared with the prior art, the netilmicin sulfate freeze-dried powder injection prepared by the method has good stability and high content of effective ingredients. Experiment results prove that the netilmicin sulfate freeze-dried powder injection prepared by the method does not have color changes after being stored for 24 months, is stable in a long term, and the content of effective ingredients is more than 95.30 percent.