Simultaneous determination of carvedilol and hydrochlorothiazide in tablets by derivative spectrophotometric and high-performance liquid chromatographic methods

Abstract

Rapid, precise and accurate first derivative spectrophotometric method (1D) is used for the resolution and determination of the binary mixtures of carvedilol (CRV) and hydrochlorothiazide (HCT), using a zero-crossing technique of measurement at 248nm and 285nm (peak-height) for CRV and HCT, respectively. The assay was linear over the concentration ranges 0.05-1.5 µg ml-1 (r = 0.9995, n = 10) for CRV and 0.1 – 10 µg ml-1 (r = 0.9999, n = 10) for HCT. The limit of quantitation for CRV and HCT were found to be 0.02 and 0.05 µg ml-1, respectively; while the detection limits (3σ blank) are 5 ng ml-1 and 10 ng ml-1 for respectively. The proposed method was successfully applied to the determination of CRV and HCT in laboratory prepared mixtures and in combined tablets with high percentage of recovery, good accuracy and precision. The interday and intraday precision and accuracy were evaluated by calculating the % RSD and the % error, (n = 6), were found to be in the range of 0.47 – 2.66 and 0.30 – 1.71 % for both drugs, respectively. The developed method can be used for rapid routine analysis for content uniformity and assay of pharmaceutical preparations.