Simultaneous Quantitation of Nebivolol Hydrochloride and Benidipine Hydrochloride from Tablet Formulation using Validated Stability Indicating HPLC Method

A robust validated stability-demonstrating high-performance liquid chromatography (HPLC) method is proposed to simultaneously quantify Nebivolol HCl and Benidipine HCl in a tablet formulation. The method was designed to accurately quantify the active pharmaceutical ingredients (APIs) in the presence of their degradation products, ensuring its application for stability studies. The separation was successfully done on C18 column using Methanol, H2O and Acetonitrile in a 70:15:15 (v/v/v) mobile phase ratio with flow rate of 1.0mL/min at 220nm wavelength. The method was validated according to the guidelines of International Conference on Harmonisation (ICH) for accuracy, precision, linearity, specificity, robustness, and limits of detection (LOD) and quantitation (LOQ). Both APIs showed good linearity within the concentration range of 250-750 mcg/mL for Nebivolol hydrochloride and 200-600mcg/mL for Benidipine hydrochloride in the mixture, with correlation coefficients of 0.9994 and 0.9985 respectively. The degradation studies were performed under various stress conditions including acidic, basic, oxidative and photolytic environments. The degradation products were separated from the APIs, confirming the method's stability-indicating capability. Nebivolol HCl was susceptible to oxidative stress while Benidipine HCl was found to underwent degradation under acidic and oxidative conditions. This methods effectiveness was demonstrated by its application to the assay of commercial tablet formulation, demonstrating its reliability for routine quality control and stability testing of combined Nebivolol HCl and Benidipine HCl formulations.