Spectrophotometric determination of amlodipine besylate in tablets with trinitrobenzene sulphonic acid

A rapid and simple spectrophotometric method for the determination of amlodipine besylate was developed. The method was based on the formation of a colored derivative between the drug and trinitrobenzenesulphonic acid. The reaction proceeds at room temperature in alkaline media (pH 10). The product was extracted into chloroform and the absorbance was measured at 337 nm. The Beer law limits for the procedure with extraction step were between 6.0-30.0 μg·ml^-1 AB. All variables in the method were optimized and the applicability of the method was examined by analyzing tablets containing AB. Reproducibility of the results was 1.34 % as relative standard deviation and the recovery for pure AB added to preanalyzed tablets was 99.7 %. The results were statistically in concordance with that of chloranil method, which was formerly developed. Data obtained shows that the developed method can be used for determination of AB in tablets.