Determination of cilnidipine related substances by RP-HPLC

Aim To establish an RP-HPLC method for the determination of cilnidipine related substances.Methods The separation was performed on octadecylsilane chemically boned silica column.The mobile phase was composed of acetonitrile∶0.025 mol·L-1ammonium dihydrogen phosphate solution∶cyclohexane(60∶ 39∶ 1).Column temperature was 40℃,and the flow rate was 1.5 ml·min-1.The detection was carried out with UV detector at 240 nm.Results Through intensity destructive test under this detection,main peak and impurity peak were well separated,with not being disturbed.Specificity calibration curves were linear within 1～16 mg·L-1(r=0.999 992).RSD was 0.42%(n=6).Conclusion The test shows that this method is suitable for the determination of cilnidipine related substances.