POLAROGRAPHIC-BEHAVIOR AND DETERMINATION OF OXAMNIQUINE IN DOSAGE FORMS

A highly sensitive method is described for the determination of oxamniquine in its pure form and in capsules. The proposed method depends upon the polarographic activity of oxamniquine in Britton-Robinson buffer, whereby a well-defined cathodic wave, followed by a more negative ill-defined one, was produced over the whole pH range. The first wave was characterized as being irreversible and diffusion-controlled with limited absorption properties. The current-concentration relationship was found to be rectilinear over the ranges 1 x 10(-5) to 5 x 10(-4) and 1 10(-6) to 5 x 10(-4) M in the direct current (DCT) and differential pulse polarography (DPP) modes, respectively, with a minimum detectability of 1 x 10(-7) M. The number of electrons involved in the reduction process was established through coulometric measurement at an applied potential. The mechanism of the electrode reaction was verified and confirmed through chemical reactions of the electrolyzed solution. The proposed method was successfully applied to the determination of oxamniquine in capsules, and the results obtained were in accordance with those found using the United States Pharmacopeia (USP) XXII method.