New Coated Wire Sensors for Potentiometric Determination of Gemifloxacin in Pure Form, Pharmaceutical Formulations and Biological Fluids

A simple, accurate and precise potentiometric method was developed for the determination of gemifloxacin mesylate (GFX). Three ion selective coated wire sensors have been constructed from the incorporation of (GFX) with the ion-pairing agents phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and Ammonium reineckate salt (ARS). The three sensors show nearly Nernestian response over the concentration range 1.0x10 −7 -1.0 x10 −2 mol L -1 of the drug with slopes of 56.14±0.08, 57.66±0.14 and 55.06±0.32 mV decade -1 for (GFX-PTA), (GFX-PMA) and (GFX-ARS) coated wire sensors, respectively. The electrodes exhibit a fast dynamic response of 30, 15 and 20 s for a period of 30, 35 and 25 days for (GFX-PTA), (GFX-PMA) and (GFX-ARS) coated wire sensors, respectively. The sensors exhibit good selectivity for GFX with respect to some inorganic cations, amino acids and some pharmacologically related compounds. The electrodes display stable potential response in the pH range 6-9 which indicates the applicability of these electrodes in the specified range. The method is accurate and precise as indicated by the mean % recoveries 99.49±0.52, 99.56±0.41 and 99.41±0.45 for (GFX-PTA), (GFX-PMA) and (GFX-ARS) coated wire sensors, respectively. The proposed method was successfully applied for the determination of GFX in pure form, its pharmaceutical formulations and biological fluids.