RP-HPLC Method for the Simultaneous Determination of a Quaternary Mixture of Propyphenazone, Flavoxate HCl and Two of Their Official Impurities with Dissolution Profiling of Their Tablets

A reversed-phase-high performance liquid chromatography method for simultaneous determination of paracetamol, caffeine, drotaverine HCl and their related impurities with dissolution profiling of their tablets and greenness profile assessment

A sensitive, specific and eco-friendly reversed-phase-HPLC method was developed and validated for the determination of paracetamol, caffeine and drotaverine HCl along with their related impurities. The separation was accomplished using an X-bridge C₁₈ column (5 μm; 250 mm × 4.6 mm inner diameter) and a green mobile phase consisting of methanol and 0.02 M phosphate buffer at pH 5.0 in the gradient elution mode. The detector used was a diode array detector. The proposed method was validated in accordance with the International Conference on Harmonisation guidelines. Linear regressions were found in the range of 1-100, 1-100, 2-60, 1-20, 0.50-30 and 1-15 μg/mL for paracetamol, caffeine, drotaverine HCl, p-aminophenol, theophylline and 3,4-dimethoxyphenylacetic acid, respectively. The suggested method was successfully applied for the determination of the studied drugs in their tablet dosage form without interference from any excipients. No discernible difference was found between the obtained results and official or reported methods, statistically, in terms of both accuracy and precision. Dissolution profiling of the studied tablet was also performed using the suggested procedure. Moreover, the greenness profile was assessed using three different tools, namely, the National Environmental Methods Index, the Analytical Eco-Scale and the Analytical GREEnness Metric Approach. The acquired results assert the agreement of the assay with green chemistry principles.