1. Stability Indicating RP-HPLC Method for Simultaneous Determination of Bambuterol HCl and Na Benzoate in the Presence of Bambuterol HCl Alkaline Degradation Product in Bulk and Syrups: Application to Degradation Kinetics.
- Author
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Elkady, Ehab Farouk, Tammam, Marwa Hosny, and Elmaaty, Ayman Abo
- Subjects
HIGH performance liquid chromatography ,DRUG stability ,BENZOATES ,CHEMICAL decomposition kinetics ,BETA adrenoceptors ,BRONCHODILATOR agents - Abstract
Bambuterol HCl (BMT) (bronchodilator) was subjected to stress alkaline hydrolysis. BMT alkaline degradation product (BMT-DP) was prepared, isolated and verified chemically using Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance (1H-NMR) as well as mass spectrometry. Na benzoate (BNZ) is commonly co-formulated in oral pharmaceutical preparations as a preservative. Subsequently, a simple, selective and valid stability indicating reversed phase high performance liquid chromatography (RP-HPLC) method was developed for simultaneous estimation of BMT and BNZ in the presence of BMT-DP. Chromatographic separation was achieved using an isocratic mobile phase consisting of a mixture of (20 mM)-KH2PO4(containing 0.2% Triethylamine (TEA)v/v), pH adjusted to 3 with orthophosphoric acid]: acetonitrile (70:30,v/v) with a flow rate 1 mL/min at ambient temperature on a Eurospher II C18 (250 mm × 4.6 mm, 5 μm) column. Analysis was carried out with ultraviolet detection at 215 nm for BMT and BMT-DP, and 225 nm for BNZ. Linearity, accuracy and precision were found to be acceptable over a concentration range of (1-120 μg/mL) and (2-240 μg/mL) for BMT and BNZ, respectively. Limits of detection (LODs) for BMT and BNZ were 0.056 and 0.125 μg/mL, whereas limits of quantitation (LOQs) were 0.169 and 0.378 g/mL, respectively. Moreover, the kinetics of alkaline degradation of BMT was investigated. Arrhenius plot was constructed and the apparent pseudo first-order rate constant, half-life time, shelf-life time, and the activation energy of the degradation process could be calculated. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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