Extractive spectrophotometric determination of TRODAT-1 hydrochloride in lyophilized kit

A simple, sensitive, and accurate spectrophotometric method has been developed for the assay of TRODAT-1 hydrochloride in lyophilized kit. The method is based on the formation of ion-pair association complex of TRODAT-1 with bromothymol blue (BTB) in disodium hydrogen phosphate/citric acid buffer of pH 4.0. The colored product was extracted with chloroform, and measured spectrophotometrically at 414 nm. Beer's law was obeyed in the range of 5-25 mu g/ml with molar absorptivity of 2.75 x 10(4) l/mol/cm. Optimization of experimental conditions was described for the method. The proposed method has been successfully applied for the analysis of TRODAT-1 hydrochloride in lyophilized kit. No interference with pharmaceutical excipients was observed.