Abstract
Two easy and accurate kinetic spectrophotometric approachs for determination of darifenacin hydrobromide (DAR) in bulk and in their pharmaceutical preparation have been-examined, Method I depended on measuring the producing green manganate species after oxidation of-the drug with alkaline KMnO4. Method II depended on measuring the decrease in yellow colour of ceric ammonium sulphate at 318 nm after the oxidation of darifenacin with Ce (IV) ion in acidic condition. Those reactions were followed on spectrophotometrically by assess the rate of color development at fixed time at optimum wavelength of 610 and 318 nm for the reaction with KMnO4 and Ce(IV), respectively. The different experimental conditions affecting the producing colors were carefully considered and optimized. The initial rate and fixed time procedures were used for determination of darifenacin. The calibration range was from 0.3-4.8 and 3-30 mu g/mL. The lower limit of detection were 0.21 and 0.97 mu g/mL for KMnO4 and Ce(IV), respectively. The accuracy and precision of the proposed methods were statistically validated. The results obtained by the proposed methods were compared with reference method, which showed good agreement with each other. The proposed methods have been good applied for the assay of DAR in its dosage form.