Spectrophotometric Determination of Catechol Amine Drugs in Pharmaceutical Preparations via Oxidative Coupling Reaction with 3-Amino Pyridine and Sodium Periodate

Abstract

A rapid and sensitive spectrophotometric method is described for the
determination of some Catechol amine drugs (methyldopa (I), adrenaline (II), and
dopamine (III)) in both pure and dosage forms. The proposed method uses 3-amino
pyridine as a chromogenic reagent. The method is based on the oxidative coupling
reaction of Catechol amine drugs with 3-amino pyridine and sodium periodate to form
an orange-water-soluble dye product, that has a maximum absorption at 476, 488 and
490 nm for (I), (II), and (III) respectively. The optimum reaction conditions and other
analytical parameter are evaluated. The proposed method was applied successfully to
the determination of these drugs in pharmaceutical formulation. The results have
demonstrated that the method is equally accurate and reproducible as the official
methods.