Simultaneous determination of paracetamol and caffeine by RP-HPLC in soft gelatin capsules

A rapid and stability-indicating RP-HPLC method was developed for simultaneous estimation of paracetamol and caffeine in soft gelatin capsules form especially to get some more advantages over other methods already developed for this combination. The method was validated according to ICH guideline with respect to accuracy, precision, specificity, linearity, solution stability, robustness, sensitivity, forced degradation and system suitability. For this, an isocratic condition of mobile phase comprising acetonitrile and phosphate buffer (pH 3.5) in a ratio of 15:85, v/v over YMC C18 column (250 × 4.6 mm, 5 μm) at a flow rate of 1 mL/minute at ambient temperature was maintained. The method showed excellent linear response with correlation coefficient (R2) values of 0.999 and 1.0 for paracetamol and caffeine respectively, which were within the limit of correlation coefficient (R2 > 0.995). The percent recoveries for two drugs were found within the acceptance limit of (98.0–102.0%). % RSD values for repeatability, reproducibility and Intermediate precisions were below 2.0. Forced degradation of the drug product was carried to establishing the stability-indicating property of this method and providing useful information about the degradation pathways, degradation products, and how the quality of a drug substance and drug product changes with time under the influence of various stressing conditions.