Method Development and Validation for Estimation of Flunarizine in Tablet Formulation By HPLC

Abstract

A simple, precise, accurate, and robust reversed-phase high performance liquid chromatography (RP-HPLC) method was developed and validated for the estimation of Flunarizine Hydrochloride (FLU) in bulk drug and tablet dosage form. Chromatographic separation was achieved on a C18 column (Thermo Hypersil Gold, 4.6 × 250 mm, 5 μm) using an isocratic mobile phase composed of phosphate buffer (10 mM, pH 3.5) and acetonitrile (50:50 v/v) at a flow rate of 1.0 mL/min. Detection was carried out at 254 nm using a photodiode array (PDA) detector with a total run time of 10 minutes. The method was validated as per ICH Q2(R1) guidelines for system suitability, linearity, accuracy, precision (system precision, method precision, and intermediate precision/ruggedness), robustness, and specificity. The calibration curve showed excellent linearity over the concentration range of 5–15 μg/mL (50–150% of target concentration) with a regression equation of y = 54439x – 2511.1 and correlation coefficient R² = 0.9999. The mean recovery ranged from 99.17% to 99.87% at 80%, 100%, and 120% spike levels, confirming accuracy. Precision studies demonstrated %RSD values of 0.90% (system precision), 0.05% (method precision), and 0.05% (ruggedness), all well within acceptance criteria (NMT 2.0%). Robustness was established through deliberate variations in flow rate (±10%), organic phase composition (±10%), and detection wavelength (±2 nm), with all system suitability parameters remaining within limits. The assay of marketed formulation (Flunarin® tablets, 10 mg) yielded 99.84% of label claim (%RSD: 0.16%), confirming the method's applicability for routine quality control analysis.