Stability Indicating Reverse Phase High-Performance Liquid Chromatographic Method of Isoliquiritigenin: Development, Validation, and Forced Degradation Studies.

A simple, stability-indicating RP-HPLC method was developed to estimate isoliquiritigenin (ISL) and assess its stability under acid, alkaline, oxidative, thermal, and UV stress conditions. Chromatographic separation was performed on a C18 column using UV-visible detection and a 20 μL injection volume, applying an isocratic elution approach to develop and optimize a method for quantifying ISL in stressed samples. At a constant flow rate of 1 mL/min, the mobile phase consisted of 0.1% v/v formic acid (aqueous) and acetonitrile (organic) in a 25:75 ratio. The maximum absorption wavelength (λmax) of ISL was found to be 361 nm. According to ICH Q2(R2) guidelines, the method was validated and showed linearity in the 2-10 μg/mL range (R = 0.9985) with high accuracy (98.38%-99.48% recovery) and precision (% RSD < 2%). Quantification and detection limits were 1.81 and 0.66 μg/mL, respectively. According to forced degradation testing, there was very little deterioration when subjected to thermal and photolytic stress, but there was considerable degradation when exposed to alkaline (93.40%), acidic (98.76%), and oxidative stress (63.80%) at 70°C. The developed method effectively evaluates ISL stability in both bulk and stressed conditions, supporting its use in routine quality control and pharmaceutical formulation.