Abstract

MODIFIED SCREEN PRINTED AND CONVENTIONAL CARBON PASTE ELECTRODES FOR DETERMINATION OF SILDENAFIL CITRATE IN TABLETS

Mohamed,G. G.; Nour El-Dien, F. A. F.; Frag, E. Y. Z.; Diab, M. M. A.*

*Chemistry Department, Faculty of Science, Cairo University, Gamaa Str., 12613, Giza,Egypt.

ABSTRACT

This work compares the electroactivity and the performancecharacteristics of two electrodes, the conventional modified carbonpaste(MCPE) and modified screen-printed (MSPE) electrodes for thedetermination of Sildenafil citrate (SILC) drug. The proposedelectrodes are fully characterized in terms of ion pair contents andtypes, plasticizer type, response time, life span, pH and temperature.The modified electrodes with SIL-TPB ion pair were only electrodesthat exhibite a linear responses with Nernstian slopes of 55.91 ± 1.44and 57.16 ± 0.52 mV decade-1, in the concentration ranges from 8.0 x10-7 to 1.0 x 10-2 and 5.0 x 10-7 to 1.0 x 10-2 mol L-1 for MCPE andMSPE, respectively with good reproducibility. Both MCPE and MSPEcould be used in the pH range 2.5 – 4.5 and 2.0 – 4.5 for MCPE andMSPE, respectively also the isothermal coefficients are found to be 1.04 and 1.43 mV/°C andthe limit of detection was found to be 7.07 x 10-7 and 5.62 x 10-7 mol L-1 for MCPE andMSPE, respectively. They were applied for the potentiometric determination of SILC in purestate and some pharmaceutical preparations under batch conditions. The MCPE and MSPEsensors display good selectivity for SILC drug over large number of inorganic cations, sugarsand amino acids commonly used in drug formulations.

Keywords: Modified Screen-printed electrode, Sildenafil citrate, Potentiometry,