目的　建立离子抑制色谱法测定琥乙红霉素原料的含量及有关物质的方法 ,并研究其影响因素。方法　采用ZorbaxSB C18色谱柱 ,以 0 0 2mol·L-1KH2 PO4 —乙腈 (4 5∶5 5 ,用氨试液调至 pH 6 8)为流动相 ,流速 1 2mL·min-1,检测波长 2 10nm ,柱温 (30± 0 5 )℃。结果　在选定固定相条件下 ,流动相对组分的洗脱和选择性影响最大 ,柱温次之 ,琥乙红霉素在乙腈中比较稳定。测定了有效主成分琥乙红霉素A的含量以及 7个有关物质的总含量。琥乙红霉素A的平均回收率为 99 45 % ,(RSD =2 2 4% ,n =5 )。结论　本法可用于琥乙红霉素原料的含量测定和有关物质的检查 Objective To establish a method for determining the content of erythromycin ethylsuccinate and related substances by ion-suppressed chromatography and to study the influencing factors. Methods The mobile phase was a Zorbax SB C18 column with a flow rate of 12 mL · min-1 at a flow rate of 2 mL · min-1 with a flow rate of 0.2 mL · L-1 KH2 PO4-acetonitrile (45:55, adjusted to pH 6 8 with ammonia solution) 10nm, column temperature (30 ± 0) ℃. Results Under the condition of selected stationary phase, the elution and selectivity of the mobile phase were most affected. The column temperature followed by erythromycin ethylsuccinate was more stable in acetonitrile. The content of Erythromycin ethylsuccinate succinate and the total content of seven related substances were determined. The average recovery of erythromycin ethylsuccinate was 99 45% (RSD = 224%, n = 5). Conclusion This method can be used to determine the content of erythromycin ethylsuccinate and related substances