Optimized and validated spectrophotometric methods for the determination of amiodarone hydrochloride in commercial dosage forms using N-bromosuccinimide and bromothymol blue

Two optimized and validated spectrophotometric methods have been developed for the determination of amiodarone hydrochloride in commercial dosage forms. Method A is based on the reaction of tertiary amino group of the drug with N-bromosuccinimide in methanol-acetone medium resulting in the formation of a yellow colored product, which absorbed maximally at 353 nm. Method B involves the formation of a colored chloroform extractable ion-pair complex of the drug with bromothymol blue at pH 2.32 absorbing maximally at 400 nm. Beer's law is obeyed in the concentration ranges 50-600 and 2-55 μg mL−1 with molar absorptivity of 1.58 × 102 and 1.50 × 104 L mol−1 cm−1 for methods A and B, respectively. The regression analysis yields the calibration equations: A = 4.012 × 10−4 + 1.16 × 10−3 C and A = 9.612 × 10−4 + 2.198 × 10−2 C for methods A and B, respectively. The application of the proposed methods to commercial dosage forms is presented.