Development and Validation of a Stability-Indicating RP-HPLC Method for The Simultaneous Estimation of Lansoprazole and Domperidone in Bulk and Capsule Dosage Forms

The present research focuses on the development and validation of a simple, precise, and robust reverse-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous estimation of lansoprazole and domperidone in bulk and capsule dosage forms. The method was designed in accordance with International Council for Harmonisation (ICH) guidelines to ensure reliability and reproducibility for routine pharmaceutical analysis. Chromatographic separation was achieved using a C18 column with an optimized mobile phase composition, flow rate, and detection wavelength, resulting in well-resolved peaks for both drugs without interference from excipients. System suitability parameters, including retention time, theoretical plates, and tailing factor, were evaluated and found within acceptable limits, confirming the adequacy of the chromatographic system. Linearity was established over the concentration ranges of 5–25 µg/mL for lansoprazole and 10–50 µg/mL for domperidone, with correlation coefficients (r²) greater than 0.999, indicating excellent linearity. Accuracy studies demonstrated recovery values between 98–102%, validating the reliability of the method. Precision, assessed through intra-day and inter-day studies, showed %RSD values less than 2%, confirming reproducibility. Sensitivity was established with low limits of detection (LOD) and quantification (LOQ), highlighting the method’s capability to detect and quantify trace levels of both drugs. Robustness studies, performed by deliberate variations in flow rate and mobile phase composition, revealed no significant changes in results, thereby confirming method stability. The validated RP-HPLC method was successfully applied to the analysis of capsule dosage forms, demonstrating its suitability for routine quality control and pharmaceutical formulation studies. The method’s simplicity, accuracy, precision, and robustness make it a valuable analytical tool for simultaneous drug estimation in both academic and industrial laboratories. This study contributes to the advancement of analytical methodologies by providing a reliable approach for the quality assurance of lansoprazole and domperidone formulations, ensuring compliance with regulatory standards and supporting therapeutic efficacy.