Validation of an HPLC Method for the Determination of Diclofenac Diethylamine and Three of Its Impurities in a Gel Pharmaceutical Form

Background: Monitoring impurities in drug products is a principal requirement of pharmaceutical regulatory authorities all over the world to ensure drug safety. For this reason, there is a great need for analytical QC of dugs products. Objective In this study, a simple, efficient, and direct HPLC method was developed for the determination of three impurities of diclofenac. Methods: The HPLC method was developed using a mobile phase which consisted of an HPLC grade mixture, acetonitrile-0.01M phosphoric acid adjusted to pH 2.3 (1 + 3, by volume). Results: The separation was performed in 15 min. The calibration curves of the three impurities were linear; the correlation coefficients were 0.999 at concentrations of 0.00015-0.003 mu g/mL. Conclusion: The validation of this method shows that it meets all validation criteria. This shows the reliability of this method for the routine control of diclofenac impurities. Highlights: The validation of a robust HPLC method for the determination of diclofenac impurities is of great importance for the pharmaceutical industry to control its products.