Determination of Labetalol Hydrochloride by Kinetic Spectrophotometry Using Potassium Permanganate as Oxidant

Abstract

A simple and sensitive kinetic spectrophotometric method was developed for the determination of labetalol (LBT) hydrochloride. The method was based on the kinetic investigation of the oxidation of the drug with alkaline potassium permanganate at room temperature (25 ± 1°C). The increase in absorbance of coloured manganate ions was measured at 605 nm. All experimental variables affecting the de- velopment of the colour were investigated and optimized. The initial rate and fixed time (at 6 minute) methods were adopted for determin- ing the drug concentration. The calibration graphs were linear in the concentration ranges of 2-14 µg mL -1 and 1-10 µg mL -1 , using the initial rate and fixed time methods, respectively. The method was suc- cessfully applied to the determination of labetalol in laboratory made tablets and commercial tablets. The results were validated statistically and through recovery studies.