Abstract: OBJECTIVE To improve the method for related substance determination and sample preparation of spironolactone tablets.METHODS The detection method was performed on the column of Welch Materials Eclipse XB-C₁₈column(4.6 mm×250 mm,5μm) with mobile phase of acetonitrile-water(54∶46) at flow rate of 1.0 mL·min^-1,detection wavelengths was 254 nm and 283 nm,column temperature was 35℃.The samples were extracted by flow phase ultrasonic method.RESULTS Related substances were completely separated from the principal component.The linear range of spironolactone and canrenone were 1.00-100.38μg·mL^-1 and 1.03-102.53μg·mL^-1(r=1.000),respectively.The average recovery rates were 99.52%and 99.23%,respectively.CONCLUSION The method is simple,accurate,reproducible and more convenient than the Chinese Pharmacopoeia method,which can provide reference for the optimization of the determination method of spironolactone tablets in the future.