RESUMEN
OBJECTIVE: To establish a HPLC method for the detection of related substances of allergy and congestion relief. METHODS: An Ultimate C18 column (4.6 mm × 250 mm, 5 μm) was used. Gradient elution was used to determine the related substances of ibuprofen with phosphoric acid solution (pH 2.5) as mobile phase A and acetonitrile as mobile phase B. The flow rate was 1.0 mL·min-1 and the detection wavelength was set at 214 nm. As for the related substances of phenylephrine and chlorphenamine, gradient elution was used with acetonitrile -0.1% octanesulfonic acid sodium (pH was adjusted to 3.0 with phosphoric acid) (20:80) as mobile phase A and acetonitrile-phosphate buffer (1.15% ammonium dihydrogen phosphate, 0.1% octanesulfonic acid sodium, pH adjusted to 3.0 with phosphoric acid) (60:40)as mobile phase B. The flow rate was 1.5 mL·min-1, and the detection wavelength was set at 215 nm. RESULTS: The related substances were completely separated from the principal components. The detection limits were 50.5, 42.9, 52.5 and 47.4 ng·mL-1 for ibuprofen, ibuprofen's impurity C, phenylephrine, and chlorphenamine, respectively. CONCLUSION: The method is suitable for detection of the related substances in allergy and congestion relief.