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

Diphenylpyraline hydrochloride (Di-HCl) has been determined in raw material and its pharmaceutical prepara- tion 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 in- creases linearly within the concentration range 4.5 x 10 -4 -1x10 -2 mol/L of the investigated drug. The concentration of Di- HCl in raw drug material and in its pharmaceutical preparations was determined using standard addition method, Randles- Sevcik equation and indirectly via its complexation with sodium tetra phenylborate (NaTPB), the obtained average recov- eries were 101.44 and 100.49 with standard deviation (SD) 0.45 and 0.38 (n = 4) for platinum and glassy carbon elec- trodes 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 associa- tion 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).