Flow injection potentiometric determination of Chlorphenoxamine Hydrochloride

New Chlorphenoxamine (Ch) ion selective plastic membrane electrodes for both conventional and coated wire types based on the ion associate of Ch-HCl with sodium tetraphenylborate (NaTPB) and phosphotungestic acid (PTA) were prepared. The conventional type electrode was fully characterized in terms of membrane composition, plasticizer, filling solution, life span, pH, ionic strength, temperature. The membranes of optimum compositions were used for the preparation of both graphite and cupper coated wire electrodes. The prepared electrodes were used for the potentiometric determination of the investigated drug in raw material and pharmaceutical preparations under batch and flow injection analysis conditions. The selectivity of the electrodes towards a large number of excipients like inorganic cations, sugars, amino acids and other antihistaminic drugs was tested. Determination of Ch-HCl, the solubility product of the ion associate and the formation constant of the precipitation reaction leading to the ion associate formation of Ch-HCl with NaTPB and PTA were carried out using conductimetric measurements.