RESUMO
Objective: To establish and validate a high performance liquid chromatography(HPLC)method for the determination of related substances in etoricoxib tablets. Methods: The related substances in the etoricoxib tablets were determined by HPLC. The Waters C18 column(4.6 mm×150 mm,3.5 μm)was used. The mobile phase consisted of the aqueous 0.02 mol/L sodium dihydrogen phosphate solution and acetonitrile(71:29,V/V)and the flow rate was 0.6 ml/min. The detection wavelength was 235 nm. The column temperature was 40℃ and the injection volume was 10 μl. Results: The etoricoxib related substances and other degraded substances in the forced degradation test of etoricoxib were com- pletely separated under the HPLC conditions. The quantification limit and the detection limit were 0.5 ng and 1.0 ng both for etoricoxib and its N-oxide,respectively. The calibration curves showed a good linearity within the range of 61.14- 152.85 μg/ml for etoricoxib and 61.50-153.75 μg/ml for the N-oxide. The recoveries of etoricoxib and its N-oxide were both within the range of 98%-102%. The solution used for determining the related substances were kept stable within 12 h at room temperature. Conclusion: The established HPLC method showed good specificity,sensitivity and accuracy,which could be used for the determination of related substances in the etoricoxib tablets.