Use of plastic membrane ion-selective electrodes for the analysis of drug substances

Abstract

An overview is given on plastic membrane ion-selective electrodes of the conventional and/or coated-wire type constructed for 23 drug compounds. These are based on incorporation of ion-pairs or ion-associates in poly(vinyl chloride) network in the presence of dioctyl phthalate as a plasticizer. The electrodes are very selective to their respective drugs; a comparative study proved that stereospecifity is a major factor affecting their selectivity. They have a relatively large working pH-ranges (more than 4 pH units for most cases). The isothermal temperature coefficients. (dE°/dT) of the electrodes range from 2.5×10-5 to 32.0×10-4 V/°C over a wide temperature limits. The electrodes can be employed successfully for assaying the investigated drugs in many of their pharmaceutical preparations.