Validated stability indicating capillary electrophoresis method for the separation and determination of fixed dose combination of carvedilol and hydrochlorothiazide in tablets

Abstract

A novel fast, sensitive and specific capillary electrophoresis (CE) technique coupled to a diode array detector (DAD) has been developed for the separation and simultaneous determination of carvedilol (CRV) and hydrochlorothiazide (HCT) in their combination formulations. The proposed method utilized fused silica capillary (55cm × 75μm ID) and background electrolyte (BGE) composed of phosphate buffer (12.5mM, pH 7.4) – methanol (95:5, v/v). The separation was achieved at 30 KV applied voltage and at 24ºC. Atorvastatin (ATO), (80μg/mL) was chosen as the internal. The described method was linear over the range of 1-200 μg/mL and 0.2 - 150 μg/mL for CRV and HCT, respectively. Intra- and inter-day RSD (n=6) was ≤ 1.4%. The limit of detection of CRV and HCT were 0.26 and 0.07 μg/mL, respectively. The validated CE method was successfully applied to the analysis of their commercial tablets dosage forms. Forced degradation studies were performed on bulk samples of the two drugs using thermal, photolytic, hydrolytic, and oxidative stress conditions and the stressed samples were analysed by the proposed method. Degradation products produced as a result of stress studies did not interfere with the detection of CRV and HCT and the assay thus could be considered stability indicating.