Pharmaceutica Analytica Acta

Abstract

Validated Stability-Indicating UPLC and Derivative Synchronous Fluorescence Spectroscopy Methods for the Determination of Atomoxetine Hydrochloride in Pharmaceutical Preparation

Suzan Mahmoud Soliman, Heba MY El-Agizy and Abd El Aziz El Bayoumi

Two stability-indicating methods were developed for the determination of atomoxetine hydrochloride (ATM) and validated in the presence of its degradation products. Method I is based on (UPLC) separation of ATM from its alkaline, oxidative, and acidic degradation products on Zorbax SB C18 column using acetonitrile -aqueous 0.01M triethylamine, pH 4.2 (50:50, v/v) mobile phase. Photodiode array detection at 205 nm was used for quantitation of ATM over the range of 0.1-35 μg/ml. The run time was 2.5 min within which ATM and its degradation products were well separated. The method was also applied to the determination of ATM in spiked human plasma over the range of 0.1-4 μg/ml. Moreover, the produced acidic degradation products were isolated, and structural elucidation of the degradates was done by LC/MS spectrometry studies. A proposal of the acid hydrolysis pathway was presented. Method IIA describes direct measurement of the intrinsic fluorescence intensity of both ATM and its known acid degradates using sodium dodecyl sulfate as fluorescence enhancer in aqueous solutions. This method was extended to (Method IIB) to apply first derivative synchronous fluorescence spectroscopy for the simultaneous analysis of ATM and its acidic depredates. The proposed methods were successfully applied to quantify ATM in commercial capsules and the results were in good agreement with those obtained using a reference method.