Abstract

Two simple, specific, accurate and precise methods, namely, reverse phase high performance liquid chromatography and high performance thin layer chromatography were developed for estimation of carvedilol in bulk drug and pharmaceutical formulations. For the high performance liquid chromatography method, Lichrospher 100 C-18, 5 µm column consisting of 200×4.6 mm i.d. in isocratic mode, with mobile phase containing 50 mM KH₂PO₄ buffer (pH 3.0±0.1): acetonitrile: methanol (60:50:10 v/v/v) was used. The flow rate was 1.0 ml/min and effluent was monitored at 242 nm. The retention time was 4.56±0.03 min. For the high performance thin layer chromatography method a Camag high performance thin layer chromatography system comprising of Linnomat V automatic sample applicator, Hamilton Syringe, Camag TLC Scanner-3, Camag Win CAT software with stationary phase precoated silica gel 60F₂₅₄ and mobile phase consisting of ethyl acetate: toluene: methanol (1:4:3.5 v/v/v). The detection of spot was carried out at 242 nm. The Rf value was 0.65±0.02. The methods were validated in terms of linearity, accuracy and precision. The linearity curves were found to be linear over 1-35 µg/ml for high performance liquid chromatography and 50-300 ng/spot for high performance thin layer chromatography. The limit of detection and limit of quantification for high performance liquid chromatography were found to be 0.2 and 0.85 µg/ml, respectively, and for high performance thin layer chromatography, 10 and 35 ng/spot, respectively. The proposed methods were successfully used to determine the drug content of marketed formulations.