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

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