Simple and facile methods for the determination of carvedilol in pharmaceuticals

Abstract

Simple and sensitive methods for the determination of carvedilol (CAR) are described. The methods are based on the reaction of CAR with ninhydrin (NIN) in basic medium to form coloured iminium salt having absorption maximum at 402 nm and also with acetaldehyde (AA) in presence of sodium nitroprusside in basic medium to form coloured product having absorption maximum at 558 nm. The calibration graphs are found to be linear over 0.2 - 1.2 and 0.6 - 2.0 µg mL⁻¹ with molar absorptivity values of 2.571 × 10⁴ and 1.617 × 10⁴ L mol⁻¹ cm⁻¹ for CAR-NIN and CAR-AA respectively. The optimum reaction condition and other analytical parameters were evaluated. The statistical evaluations of the methods were examined by determining intra-day and inter-day precision. The methods were successfully applied to the assay of CAR in tablet formulations. The accuracy and reliability of the methods were further ascertained by parallel determination by a reference method and by calculating the Student’s t-test and F-test values at 95% confidence level.