Ionisable substances chromatography: A new approach for the determination of Ketoprofen, Etoricoxib, and Diclofenac sodium in pharmaceuticals using ion – pair HPLC

An ion-pair HPLC method was developed and validated to analyze three of non-steroidal anti-inflammatory drugs (Ketoprofen, Etoricoxib, and Diclofenac sodium) in their pure and pharmaceuticals based on their ionisable characteristics. Cetyltrimethylammonium bromide (Cetrimide) was used as an ion pair reagent since it had not been used before for this purpose. Chromatographic analysis was accomplished using the C18 (250 × 4.6 mm, 5μm) column. Mobile phase consisted of a mixture of 50% Cetrimide [Formula: see text] M and 50% acetonitrile to analyze Ketoprofen and Etoricoxib, whereas for Diclofenac sodium, mobile phase was a mixture of 30% Cetrimide [Formula: see text] M and 70% acetonitrile. pH value was adjusted if necessary to 10 with ammonium hydroxide. The flow rate was 1mL/min and detection wavelengths were at 254 nm, 234 nm, and 254 nm for Ketoprofen, Etoricoxib, and Diclofenac sodium; respectively under ambient temperature. Retention times ([Formula: see text]) were 9.41, 7.34, and 6.66 for Ketoprofen, Etoricoxib, and Diclofenac sodium; respectively. The proposed method was evaluated for linearity, accuracy, precision, and specificity according to ICH guidelines. Ketoprofen, Etoricoxib, and Diclofenac sodium were detected in the following linear ranges: (0.031–0.500mg/mL), (0.007–0.110g/mL), and (0.016–0.250mg/mL); respectively with excellent mean recovery values (98.0–102.0%). RSD% was in an acceptable range (less than 2), proving the precision of the developed method. Specificity was proved in the presence of degradation products. Furthermore, a comparison between the results of this study and the reported HPLC methods indicated that this developed method was better in terms of simplicity, analysis time, and no use of buffers in the mobile phase. In conclusion, the developed method can successfully detect Ketoprofen, Etoricoxib, and Diclofenac sodium quantitatively and qualitatively in their dosage forms without any interference with excipients, making this method valuable, reliable, and practical to be applied in quality control laboratories.