RESUMO
OBJECTIVE: To establish the determination method of the related substances in ibuprofen raw materials, tablets and capsules. METHODS: High performance liquid chromatography (HPLC) was used for the determination of 2-(4-isobutyl phenyl) propanoic acid, 4-isobutyl benzoic acid, sodium methyl hydroxybenzoate(provided by national institutes for food and drug control), 4′-isobutyl acetophenone (known impurities of JP), the relative substance A, J, N (known impurities of EP), and the unknown impurities. A Kromasil C18 column (4.6 mm × 250 mm, 5 μm) was used as the analytical column, acetonitrile-water (pH adjusted to 3.0 by phosphoric acid) (45:55) were used as the mobile phase, the flowing rate was 1.0 mL · min-1, the detection wavelength was set at 254 nm, and the column temperature was 35°C. RESULTS: The relative substances detected in ibuprofen raw materials and its preparations were mainly 4-isobutyl benzoic acid and 4′-isobutyl acetophenone. The contents of unknown impurities were also high in the preparations of some manufacturers. CONCLUSION: The method can be used for the analysis of the related substances in ibuprofen raw materials and its preparations.