Membrane sensors for the selective determination of tiapride in presence of its degradation products

Abstract

The construction and electrochemical response characteristics of polyvinyl chloride (PVC) membrane sensors for determination of tiapride in presence of its degradation products are described. The sensors are based on the ion association complexes of tiapride cation with sodium tetraphenyl borate (Tia-TPB) [sensor 1]) or ammonium reineckate (Tia-R) [sensor 2] counter anions as ion exchange sites in PVC matrix. The performance characteristics, sensitivity and selectivity of these electrodes in presence of tiapride degradation products were evaluated according to IUPAC recommendations. It reveals a fast, stable and linear response for tiapride over the concentration range 10-5-10-2 M with cationic slopes of 28.997 and 30.580 mV per concentration decade with sensors 1 and 2, respectively. These sensors exhibit fast response time (20-30 s), low quantitation limit (4.5×10-6 and 3.6×10-6, respectively), and good stability (6-8 weeks). The direct potentiometric determination of tiapride hydrochloride using the proposed sensors gave average recoveries of 99.95±0.678 and 99.92±1.157 for sensors 1 and 2, respectively. The sensors are used for determination of tiapride hydrochloride, in pure form, in presence of its degradation products in tablets, and in plasma. Validation of the method shows suitability of the proposed sensors for use in the quality control assessment of tiapride hydrochloride and for routine analysis as stability indicating method. The developed method was found to be simple, accurate and precise when compared with a reference company spectrophotometric method. © 2007 The Pharmaceutical Society of Japan.