A validated stability-indicating UPLC method for determination of diclofenac sodium in its pure form and matrix formulations

The aim of this work is to develop a validated stability indicating reverse phase ultra performance liquid chromatography (UPLC) method for the rapid and accurate determination of diclofenac sodium in its pure form and in matrix formulations. This UPLC method is composed of isocratic mobile phase, 0.05M ammonium acetate buffer (pH=2.5) and acetonitrile (50:50), with flow rate 0.5ml/min, column BEH C18 (2.1×50mm, 1.7μm). The method is rapid (1.2min run), selective with well resoluted diclofenac peak with retention time 0.94min and sensitive (LOD=2ppm and LLOQ=6ppm) with UV detection at 254nm. The drug was subjected to acidic, alkaline media, boiling and oxidizing agent to apply stress conditions. The developed method was able to separate degradation product generated under forced degradation studies. The developed method was validated as per the FDA guidelines for specificity, linearity, accuracy, precision, LOD, LLOQ and found to be satisfactory. The study suggests that the developed UPLC method can be used for the assessment of drug purity and stability. It can be also used to monitor the drug content and release from different formulations without any interference of excipients and/or degradation products.