Spectrophotometric determination of dobutamine hydrochloride using 3-methylbenzothiazolin-2-one hydrazone

Abstract

A spectrophotometric procedure is described for the determination of dobutamine hydrochloride. The proposed method uses 3-methylbenzothiazolin-2-one hydrazone as the chromogenic reagent. A mixture of aqueous solutions of the drug and reagent is treated with cerium(IV) ammonium sulphate in an acidic medium. Dobutamine reacts to give a pink colour with a λ_max. at 510 nm (ε_max.= 1.5 × 10⁴ l mol^–1 cm^–1). Beer's law is obeyed in the concentration range 4–20 µg ml^–1 of dobutamine in the final assay solution. The procedure described was successfully applied to the determination of the bulk drug and its dosage form (Dobutrex vials).