Rp-HPLC Method Development and Validation for Simultaneous Estimation of Polmacoxib and Paracetamol in Tablet Dosage Form

A simple, accurate, precise, and robust reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous estimation of Polmacoxib and Paracetamol in combined tablet dosage form. Chromatographic separation was achieved using a Shim-pack NT-ODS C18 column (250 × 4.6 mm, 5 µm). The mobile phase consisted of phosphate buffer (pH 5.5) and acetonitrile in the ratio of 40:60 (v/v), with the addition of 1 mL ortho-phosphoric acid, delivered at a flow rate of 1.0 mL/min. Detection was carried out at 238 nm using a PDA detector. The retention times for Paracetamol and Polmacoxib were found to be 4.16 min and 10.61 min, respectively, indicating efficient separation and good resolution between the two analytes. The developed method was validated according to ICH guidelines, evaluating parameters such as specificity, linearity, precision, accuracy, robustness, LOD and LOQ. The method showed excellent linearity over the concentration range of 325–975 µg/mL for Paracetamol and 2–6 µg/mL for Polmacoxib, with correlation coefficients approaching 0.999. Accuracy was confirmed through recovery studies, yielding results within the acceptable range of 98–102%. Precision studies demonstrated %RSD values below 2%, indicating good reproducibility. Forced degradation studies under acidic, basic, oxidative, and thermal conditions established the stability-indicating nature of the method, with Polmacoxib exhibiting greater stability than Paracetamol.