Spectrophotometric determination of imipramine and promazine through ion-pair formation with molybdenum [V] and thio-cyanate

ABSTRACT

A new procedure for determining imipramine and promazine by forming ion-pairs with molybdenum [V]-thiocyanate complex is studied. The method consists of extracting the ion-pair formed into dichloromethane from hydrochlorid acid medium which is orange-red in color. The ion- pair has an absorption maximum at 472 nm with molar absorptivities of 1.27 x 104 and 1.64 x 104 M mole-1 cm-1 for imipramine and promazine hydrochlorides, respectively. The ion-pair is stable for over one week at room temperature [25C]. Bent and French's method indicated 1 4 2 composition for molybdenum [V]-thiocyanate- imipramine or promazine ion-pair. The method obeys Beer's law in the concentration range 1.0-30.0 mug ml-1 of imipramine hydrochloride and 0.8-24.0 mug ml-1 of promazine hydrochloride. The proposed method can be applied to the determination of imipramine and promazine hydrochlorides in pharmaceutical preparations