OBJECTIVE:To study the relationship between acidity and potency of amikacin sulfate & the content of sulfate radical in sample.METHODS:The sulfate radical moles in amikacin sulfate was assaged by barium sulfate gravimetric method,the potency and acidity of sample was determined.RESULTS:The content of sulfate radical in sample was related to its potency and acidity.CONCLUSION:Sulfate radical moles in Chinese Pharmacopeia (edition 1995) was not a match for the acidity range & content requirement. Here are three suggestions to adjust:①Modifying the sulfate radical moles in amikacin sulfate structure to less than 1.8.Then both the carrent acidity & content limit are not changed.②Adopting the regulation in USP ⅩⅩⅢ.③Readjusting the acidity range to pH 3.0～7.0 nad the equivalent of not less than 675μg amikacin per mg.