Potentiometric sensor for hydroxyzine determination

A new polymeric membrane electrode has been developed for the determination of hydroxyzine. The electrode was constructed by solubilizing the hydroxyzine silicotungstate ion pair into a polyvinylchloride matrix plasticized by nitrophenyloctylether. The electrode exhibited a near-Nernstian response (57 mV/decade) in the concentration range comprised between 1 x 10-2 M and 6 × 10-7 with a lower limit of detection of 2.5 × 10-7 M. The electrode response was not sensitive to pH changes between 2.8 and 6.9 and not affected by possible interfering species such as cetirizine and pharmaceutical excipients. The electrode was successfully applied to the determination of hydroxyzine in pharmaceuticals and in a dissolution profile study of tablets. The results were validated by comparison with LC and spectrophotometric assays according to the USP Pharmacopoeia methods.