Nguyen et al.: Determination of Carvedilol and its ImpuritiesThis study aimed to develop a simple and fast reverse-phase high performance liquid chromatographydiode array detection method for the simultaneous determination of carvedilol and five impurities (A, B, C, D, E) in tablets. The separation was carried out by Zorbax Eclipse XDB-C8 (150×4.6 mm; 5 µm) column. Isocratic elution was carried out using a mobile phase mixture of acetonitrile and phosphate buffer pH 2 (containing 1.5 mM 1-heptanesulfonic acid) in the ratio of 43:57 (v/v); while the flow rate was maintained at 0.7 ml/min. The impurity E was detected at 220 nm, carvedilol and other impurities were detected at 240 nm by a photodiode array detector. The good linearity was obtained with correlation coefficients (r 2 ) greater than 0.995 in the range of 0.01-1500 µg/ml for carvedilol, 0.04-3.0 µg/ml for impurity A and 0.1-3.0 µg/ml for impurities B, C, D, E. Inter-day and intra-day accuracy and precision data were within the acceptable limits. This new method has satisfactory applications in the quality control of pharmaceuticals containing carvedilol.