Differential Pulse Voltammetric and Conductimetric Determination of Diphenylpyraline HCl in Raw Material and Pharmaceutical Preparation

Diphenylpyraline hydrochloride (Di-HCl) has been determined in raw material and its pharmaceutical preparation Eskornade capsule (5mg/capsule) using differential pulse voltammetry (DPV) and conductimetric determination. It was found that Di-HCl gives a characteristic cyclic voltammetric (CV) and differential pulse voltammetric (DPV) peak in acetonitrile using platinum and glassy carbon sensors as working electrodes. The peak current (Ip) of the DPV peak increases linearly within the concentration range 4.5 x 10 -4 -1x10 -2 mol/L of the investigated drug. The concentration of DiHCl in raw drug material and in its pharmaceutical preparations was determined using standard addition method, RandlesSevcik equation and indirectly via its complexation with sodium tetra phenylborate (NaTPB), the obtained average recoveries were 101.44 and 100.49 with standard deviation (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 peak current (Ip) and peak potential (Ep) was investigated. In addition a simple and sensitive conductimetric method was used for determination of Di-HCl based on its ion association with sodium tetraphenylborate (NaTPB). The effect of solvent, reagent concentration, temperature and molar ratio was studied. The obtained average recovery was 101.44 with SD 0.45 (n = 4).