Novel PVC-membrane electrode for flow injection potentiometric determination of Biperiden in pharmaceutical preparations

The construction and performance characteristics of Biperiden (BP) polyvinyl chloride (PVC) electrodes are described. Different methods for electrode fabrication are tested including; incorporation of BP-ion pairs (BP-IPs), incorporation of ion pairing agents, or soaking the plain electrode in BP-ion pairs suspension solution. Electrode matrices were optimized referring to the effect of modifier content and nature, plasticizer and the method of modification. The proposed electrodes work satisfactorily in the BP concentration range from 10−5 to 10−2 mol L−1, with fast response time (7 s) and adequate operational lifetime (28 days). The electrode potential is pH independent within the range 2.0–7.0, with good selectivity towards BP in presence of various interfering species. The developed electrodes have been applied for potentiometric determination of BP in pharmaceutical formulation under batch and flow injection analysis (FIA) conditions. FIA offers the advantages of accuracy and automation feasibility with high sampling frequency. The dissolution profile for Akineton tablets (2 mg BP/tablet) was studied using the proposed electrode in comparison with the official methods.