Development and Validation of a Reversed-Phase Stability-Indicating HPLC Assay Method for the Simultaneous Determination of Esomeprazole Magnesium Trihydrate and Itopride Hydrochloride in Solid Dosage Forms

Research Article

Abstract

An isocratic reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of esomeprazole magnesium trihydrate and itopride hydrochloride in bulk drug and solid dosage forms. Separation was achieved on a HiQ Sil C18HS column (250 mm×4.6 mm, 5 μm) using a mobile phase consisting of acetonitrile and 2 mM phosphate buffer (pH 7.0) containing 0.06% w/v tetrabutylammonium hydrogen sulphate (15:85 v/v) at a flow rate of 1.0 mL/min. Photodiode array detection was performed at the isobestic wavelength of 290 nm, yielding retention times of 15.09 min for itopride and 17.67 min for esomeprazole. The method was validated according to International Council for Harmonisation guidelines, showing linear responses over 50 to 750 μg/mL for esomeprazole and 100 to 500 μg/mL for itopride. Method precision showed relative standard deviations below 1.0%, and mean recoveries from commercial capsules ranged from 98.78% to 99.49% for esomeprazole and 99.98% to 99.99% for itopride. The validated procedure was successfully applied to forced degradation studies conducted under hydrolytic (acidic, alkaline, neutral), oxidative, photolytic, and thermal stress conditions. Esomeprazole magnesium trihydrate exhibited substantial degradation under hydrolytic, oxidative, and photolytic conditions, producing up to eleven resolved degradation products, whereas itopride hydrochloride degraded selectively under concentrated acidic and alkaline reflux while remaining stable under neutral, oxidative, photolytic, and thermal stress. Photodiode array peak purity analyses confirmed that both drug peaks remained spectrally homogeneous without co-eluting degradants, establishing the method as stability-indicating for routine quality control and stability evaluations