Novel Modified Carbon Paste Sensors for Determination of Benzydamine Hydrochloride in Pharmaceutical Formulations and Biological Fluids

A simple, rapid and sensitive method for the determination of benzydamine hydrochloride (Benz) in pure, pharmaceutical compounds and biological fluids (human urine and plasma) using two novel carbon paste sensors was developed. The first sensor (sensor A) is based on benzydamine phosphotungstate as ion-pair and the second sensor (sensor B) based on benzydamine phosphomolybdate. Among five different solvent mediators tested, dibutyl phthalate (DBP) exhibited a proper behavior including Nernstian slopes of the calibration curves at 59.5±0.5 and 58.4±0.5 mV/decade for sensors A and B, respectively. The response times were 5 and 8 s; detection limits 4.1 x10-6 and 3.8 x10-6 mol L-1; the concentration range 7.2 x10-6 -1.0x10-2 mol L-1 and 5.8 x10-6 -1.0x10-2 mol L-1, respectively. The response is independent of the pH of test solution within the range 3–8 for both sensors. The present sensors show good discrimination of benzydamine hydrochloride from several inorganic cations, sugars and amino acids. Potentiometric and standard addition methods were applied successfully for the determination of benzydamine hydrochloride in pure solution, pharmaceutical compounds and biological fluids.