ABSTRACT
OBJECTIVE:To establish a method for the determination of related substances in Thioctic acid injection. METH-ODS:HPLC was performed on the column of Agilent Eclipse Plus C18 with mobile phase A of 0.005 mol/L potassium dehydroge-nate phosphate solution(adjusted with phosphoric acid to pH 3.0 to 3.1)and B of methanol:aoetonitrile(1∶1,V/V)(gradient elu-tion) at a flow rate of 1.2 ml/min;detection wavelength was 215 nm,column temperature was 35 ℃,and the injection volume was 20 μl. RESULTS:Under the established chromatographic conditions,thioctic acid with impurities and its degradation products were well separated;the linear range of thioctic acid was 0.828-52.992 μg/ml(r=0.999 9);RSDs of precision and stability tests were lower than 3%;recovery of impurity A was 98.45%-105.73%(RSD=2.41%,n=9);the largest single impurity content in mass fraction was 0.152%-0.189%,the total impurity content in mass fraction was 0.487%-0.516%. CONCLUSIONS:The meth-od is simple,accurate,specific and sensitivity,and can be used to determine the related substances of the Thioctic acid injection.