Differential pulse voltammetric determination of chlorphenoxamine hydrochloride and its pharmaceutical preparations using platinum and glassy carbon electrodes

Voltammetric methods have been used for the determination of chlorphenoxamine hydrochloride (Ch-HCl) in raw material and in its pharmaceutical preparations (Allergex and Allergex caffeine tablet). It was found that Ch-HCl gives a characteristic cyclic voltammetric (CV) and differential pulse voltammetric (DPV) peak in acetonitrile using platinum and glassy carbon working electrodes. The I _p of the DPV peak increases linearly within the concentration range from 4.5 × 10⁻⁴ to 1.0 × 10⁻² mol L⁻¹ of the investigated drug. The concentration of Ch-HCl in raw drug material and in its pharmaceutical preparations was determined using the standard addition method, Randles–Sevcik equation and indirectly via its complexation with sodium tetraphenylborate (NaTPB). The obtained over all average recoveries were 101.44 and 100.49% with SD 0.45 and 0.38 (n = 4) for platinum and glassy carbon electrodes, respectively. The effect of scan rate, sample concentration, and supporting electrolyte on the I _p and E _p was also investigated.