title: Membrane sensors for the selective determination of donepezil hydrochloride.
abstract: The construction and electrochemical response characteristics of polyvinylchloride (PVC) membrane sensors for donepezil HCl (DP) are described. The sensing membranes incorporated ion-association complexes of DP cation and sodium tetraphenyl borate (sensor 1), phosphomolybdic acid (sensor 2), or phosphotungstic acid (sensor 3) as electroactive materials. The sensors displayed a fast, stable, and near-Nernstian response over a relatively wide DP concentration range (1 x 10(-2) to 1 x 10(-6) M), with cationic slopes of 53.0, 54.0, and 51.0 mV/ concentration decade over a pH range of 4.0 to 8.0. The sensors showed good discrimination of DP from several inorganic and organic compounds. The direct determination of 2.5-4000.0 microg/mL DP showed average recoveries of 99.0, 99.5, and 98.5%, and mean RSDs of 1.6, 1.5, and 1.7% at 100.0 microg/mL for sensors 1, 2, and 3, respectively. The proposed sensors have been applied for direct determination of DP in two pharmaceutical preparations. The results obtained for determination of DP in tablets using the proposed sensors compared favorably with those obtained using an HPLC method. The sensors have been used as indicator electrodes for potentiometric titration of DP.
authors.affiliation: King Saud University, College of Pharmacy, Pharmaceutical Chemistry Department, PO Box 2457, Riyadh 11451, Saudi Arabia. gamal_most@yahoo.com
authors.forename: Gamal Abdel Hafiz
authors.initials: GA
authors.lastname: Mostafa
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hefnawy
authors.forename: Abdulrahman
authors.initials: A
authors.lastname: Al-Majed
mesh_terms: D002623:Chemistry Techniques, Analytical; D002800:Cholinesterase Inhibitors / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D000077265:Donepezil; D004305:Dose-Response Relationship, Drug; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007189:Indans / Q000737:chemistry*; D007477:Ions; D008567:Membranes, Artificial; D008956:Models, Chemical; D008982:Molybdenum / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D010772:Phosphotungstic Acid / Q000737:chemistry; D010880:Piperidines / Q000737:chemistry*; D011199:Potentiometry / Q000379:methods; D015203:Reproducibility of Results; D013775:Tetraphenylborate / Q000737:chemistry; D013997:Time Factors
chemical_list: D002800:Cholinesterase Inhibitors; D007189:Indans; D007477:Ions; D008567:Membranes, Artificial; D009930:Organic Chemicals; D010756:Phosphoric Acids; D010880:Piperidines; D010772:Phosphotungstic Acid; D013775:Tetraphenylborate; D008982:Molybdenum; D000077265:Donepezil; C003125:phosphomolybdic acid