Development and validation of RP-HPLC method for simultaneous estimation of lidocaine and nifedipine in pure and combined dosage form

The simultaneous estimation of Lidocaine and Nifedipine using reversed-phase high-performance liquid chromatography (RP-HPLC) is essential for analysing both the bulk drug and its topical dosage form. The objective of this study was to develop a novel HPLC method for the simultaneous estimation of Lidocaine and Nifedipine. The method aimed to provide accurate and precise results for both the bulk drug and topical dosage form. The HPLC method employed a C18 column measuring (150 mm × 4.6 mm × 5 µm). A mobile phase consisting of a mixture of methanol and water in a ratio of 80:20 v/v was used. The flow rate was set at 1.0 ml/min, and the detection wavelength was set at λ-max 236 nm. The retention time for Lidocaine was determined to be 2.560 min, while for Nifedipine it was found to be 5.470 min. The developed HPLC method demonstrated good linearity for both Lidocaine and Nifedipine, as evidenced by the obtained correlation coefficients (R2) of 0.9890 and 0.9986, respectively. The accuracy studies yielded results within the acceptable range of 98.11% - 105%. Additionally, the precision of the method was established with % RSD values of less than 2% for routine analysis of lidocaine and nifedipine. This method provides a reliable and effective approach for the simultaneous estimation of lidocaine and nifedipine, contributing to the quality control and safety assessment of pharmaceutical formulations containing these compounds.