Ion Selective Membrane Electrodes for Stability-Indicating Determination of Amisulpride

This work describes the construction and electrochemical response characteristicsfor three different polyvinyl chloride (pvc) membrane sensors for determination ofamisulpride in presence of its degradation products and commonly used excipients. the firsttwo sensors are based on the ion association complexes of amisulpride cation with sodiumtetraphenyl borate (tpb) [sensor 1] or ammonium reineckate (r) [sensor 2] counter anions asion exchange sites in pvc matrix. b-cyclodextrin (b-cd)-based technique with tpb as afixed anionic site in pvc matrix was used for fabrication of the third membrane sensor[sensor 3]. the performance characteristics, sensitivity and selectivity of these electrodes inpresence of amisulpride degradation products were evaluated according to iupacrecommendations. fast, stable and linear response was obtained for amisulpride over theconcentration range 1×10-6-1×10-2 m for sensors 1 and 3 while for sensor 2 it was found to be1×10-5-1×10-2 m. the proposed sensors showed stable nernstian responses of 29.1, 28.2 and31.1 mv per concentration decade with sensors 1, 2 and 3, respectively. these sensors exhibitfast response time (10-20 s) and good stability (4-6 weeks). the direct potentiometricdetermination of amisulpride in its pure form using the proposed sensors gave averagerecoveries of 99.93±0.72, 100.01±0.93 and 99.94±0.87 for sensors 1, 2 and 3, respectively.the sensors were used for determination of amisulpride, in pure form, in presence of itsdegradation products, in tablets and in plasma. validation of the method shows suitability ofthe proposed sensors for use in the quality control assessment of amisulpride and for routineanalysis as stability indicating method. the developed method was found to be simple,accurate and precise when compared with a reported rp-hplc method.