Monitoring of Risperidone in Pharmaceutical Formulations by a Novel Solid-Contact PVC Membrane Potentiometric Sensor

Risperidone (RSP) is an antipsychotic medication commonly used in the treatment of schizophrenia, schizoaffective and some forms of bipolar disorder. A novel RSP all-solidstate potentiometric membrane electrode (ASS-PME) was introduced for assay of risperidone active ingredient in dosage forms. The ASS-PME was made of a copper wire coated with a layer of conductive graphite-epoxy resin, a layer of carbon dots and finally a PVC sensing layer. The PVC layer was composed of 30% of PVC, 61% of dibutylphthalate (DBP) as solvent mediator, 2% of an ionic additive (sodium tetraphenyl borate (NaTPB)) and 7% of an ion-pair of RSP-TPB as a sensing material. The device worked well under laboratory condition and showed a Nernstian response of 58.2±0.4 mV/decade from 1.0×10-7 M to 1.0×10-3 M of the analyte with lower detection limit of 8.3×10-8 M. The ASS-PME has excellent selectivity toward RIS in presence of excipients in its pharmaceutical dosage forms.