Development and Validation a Method for Estimation of Lamotrigine using RP-HPLC

Abstract

A stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the quantitative estimation of lamotrigine in bulk and tablet formulations. The method utilized a Thermo C18 column (250 × 4.6 mm, 5 μm) with a mobile phase of 10 mM potassium dihydrogen phosphate (pH 3.5, adjusted with orthophosphoric acid) and acetonitrile (15:85 v/v) at a flow rate of 1.0 mL/min. Detection was performed at 224 nm. The method was validated as per ICH Q2(R1) guidelines, demonstrating linearity (5–25 μg/mL, r² = 0.999), accuracy (98.28– 99.34% recovery), precision (%RSD < 2), and robustness. Forced degradation studies under acidic, alkaline, oxidative, and thermal conditions confirmed the method’s stability-indicating capability, with degradation ranging from 3.35% to 16.68%. The method was successfully applied for assaying lamotrigine in commercial tablets (99.40% assay, %RSD = 0.125), proving its suitability for routine quality control in pharmaceutical analysis.