Novel Poly (vinyl chloride) Matrix Membrane Sensors for Determination of Cilostazol in Presence of Its Degradation Product and in Plasma

Three novel techniques for selective determination of Cilostazol in presence of its oxidative degradation product were described. The three techniques involve the construction and studying of electrochemical response characteristics of novel poly (vinyl chloride) [PVC] matrix membrane sensors for cilostazolcation by using the ion-association complexes of this cation with sodium tetraphenyl borate (NaTPB), phosphotungestic acid (PTA) and ammonium reineckate (amm.RNC) counter anions as ion exchange sites in a plasticized PVC matrix, either as ion selective membranes, microcoated wire or as micro sized graphite selective sensors. The preparation and full characterization of these sensors, including composition, life span, usable pH range, response time and temperature were described. The electrodes were used for potentiometric determination of cilostazol in pure form, pharmaceutical products, plasma and in presence of its oxidative degradation product. These sensors showed near-Nernstian slopes of 56.14, 58.82, 56.23, 56.7, 59.14, 56.84, 58.72, 59.44 and 58.37mV over the concentration ranges of 1.0×10-7-1.0×10-2 M for NaTPB and PTA sensors and 1.0×10-6-1.0×10-2 M for amm.RNC sensors. The electrodes show good selectivity for cilostazol relative to a large number of inorganic cations, organic cations, sugars and amino acids. The behavior of the three sensors in presence of human plasma was also studied and reasonable results were obtained. The methods were successfully applied for determination of the intact drug in bulk powder and in presence of its oxidative degradation product; therefore it can be used as stability indicating methods.