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Precision improvement for omeprazole determination through stability evaluation

Authors

  • Cecilia Mariana Peralta,

    Corresponding author
    1. Instituto de Química de San Luis (INQUISAL-CONICET), Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. ARGENTINA
    • Instituto de Química de San Luis (INQUISAL-CONICET) Facultad de Química, Bioquímica y Farmacia. Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. Argentina.
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  • Liliana Patricia Fernández,

    1. Instituto de Química de San Luis (INQUISAL-CONICET), Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. ARGENTINA
    2. Área de Química Analítica, Facultad de Química, Bioquímica y Farmacia. Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. ARGENTINA
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  • Adriana Noemí Masi

    1. Instituto de Química de San Luis (INQUISAL-CONICET), Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. ARGENTINA
    2. Área de Química Analítica, Facultad de Química, Bioquímica y Farmacia. Universidad Nacional de San Luis. Chacabuco y Pedernera. 5700 - San Luis. ARGENTINA
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Abstract

A new spectrofluorimetric method for the determination of omeprazole (OMP) based on its degradation reaction catalyzed by ultraviolet (UV) light is proposed. OMP in aqueous solution is very unstable, which renders a serious difficulty for controlling its quality. It does not show native fluorescence, but when exposed to UV radiation, it generates a highly fluorescent degradation product with adequate stability for indirect OMP quantification. Under the studied optimal experimental conditions (pH, temperature, exposure time to UV radiation), a specific rate constant of 2.851 min−1-described by zero-order kinetic—was obtained for the degradation reaction. Using λexc 293 nm and λem 317 nm, a linear relationship was obtained (r2 0.9998) in the concentration range of 0.1 to 1.3 µg mL−1, with a detection limit of 1.07 10−3 µg mL−1 (S/N = 3). The methodology developed was successfully applied to OMP quality control in pure drugs and tablet dosage forms without previous treatment, with good tolerance to common excipient, and a high level of concordance between the nominal and experimental values. This work constitutes an important contribution to knowledge of the degradation mechanism of OMP. It has been shown to be appropriate for OMP quality control, to have an adequate sampling rate, low cost instrument, and to be a less polluting procedure. Copyright © 2011 John Wiley & Sons, Ltd.

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