MEMBRANE SENSORS FOR STATIC AND HYDRODYNAMIC POTENTIOMETRIC ASSESSMENT OF CETIRIZINE DRUG IN PHARMACEUTICAL FORMULATIONS

Abstract

The construction and electrochemical response characteristics of poly (vinyl chloride) (PVC) membrane sensors for the determination of cetirizine drug were described. These sensors were based on the use of the ion-association complexes of the cetirizinium cation (Cet + ) with phosphomolybdic acid (PMA) (sensor I), tetraphenylborate (TPB) (sensor II) and ammonium renickate (sensor III) counter anions as ion-exchange sites in a PVC matrix plasticized with dioctylphthalate (DOP). The sensors revealed fast, stable and Nernstian response between 9.0x10 -7 - 1.0x10 -3 mol L -1 and 5.2x10 -6 - 1.0x10 -3 mol L -1 with slope of 59.3±0.2, 60.6±0.3 and 61.5±0.2 mV and dection limits 5.3x10 -7 , 3.8x10 -6 and 5.2x10 -6 mol L -1 for sensor I, II and III respectively. The intrinsic characteristics of the detectors in a low dispersion manifold under hydrodynamic mode of operation are determined and compared with data obtained under batch mode of operation. Validation of the method reveals good performance characteristics including long life span, good selectivity for Cet + over a wide variety of other organic compounds, long term stability, high reproducibility, fast response, low detection limit, wide measurement range, acceptable accuracy and precision. Applications of the sensors for the determination of Cet + in pharmaceutical samples are also reported. The sensors offer several advantages over many of those previously described and are amenable for quality control/quality assurance assessment of the homogeneity, stability and purity of ephedrine drug tablets.