Stability-indicating high performance liquid chromatographic determination of raubasine in its binary mixture with kinetic study of raubasine acid degradation
2011
El-Sayed, Mohammad A.
Stability-indicative determination of raubasine (RAB) in the presence of its degradate and its binary mixture with almitrine dismesylate (ALM) was investigated. The degradation product had been isolated, via acid-degradation, characterized and confirmed. Selective quantification of RAB and ALM in bulk form, pharmaceutical formulations and/or in the presence of RAB degradate was demonstrated. The analytical technique adopted for quantification was high performance liquid chromatography (HPLC). Separation was performed using a ZORBAX ODS column with a mobile phase consisting of acetonitrile+phosphate buffer pH 3.4 80:20 (v/v) with UV detection at 254nm. The method showed high sensitivity with good linearity over the concentration range of 5–120 and 5–60μgmL⁻¹ for RAB and ALM respectively. The HPLC method was used to study the kinetics of RAB acid degradation that was found to follow a first-order reaction. The activation energy could be estimated from the Arrhenius plot and it was found to be 18.152kcalmol⁻¹.
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