High Performance Liquid Chromatographic Determination of the Ternary Mixture of Caffeine, Dipyrone and Drotaverine Hydrochloride in Tablet Dosage Form

This work describes a simple, rapid, and reliable HPLC method for the simultaneous determination of caffeine (CAF), dipyrone (DIP) and drotaverine hydrochloride (DRV). Chromatographic separation was achieved using a reversed phase Waters Symmetry C18 (3.9×150 mm, 5 µm particle size) column with gradient elution of the mobile phase composed of 0.05 M orthophosphoric acid and acetonitrile. The gradient elution started with 15% (by volume) acetonitrile ramped up linearly to 60% in 3 min then kept at this percentage till the end of the run. The flow rate was 1mL/min. Quantification was based on measuring peak areas at 210 nm. The analytes were resolved with retention times 1.47, 2.39 and 7.17 min for DIP, CAF and DRV, respectively. Analytical performance of the proposed procedure was validated with respect to system suitability, linearity, ranges, precision, accuracy, robustness, detection and quantification limits. The linearity ranges were 10-200, 5-100 and 5-100 µg/mL for DIP, CAF and DRV, respectively. The validated HPLC method was applied to the simultaneous determination of the three drugs in several laboratory-prepared mixtures of different ratios. Finally, laboratory made tablets containing the three drugs were assayed using the developed procedure where no interfering peaks were encountered from the tablet additives.