Fabrication of a PVC-Membrane Potentiometric Sensor Based on a Bis (Trimethylaminoethylsulfanyl)diaminophthalocyanine Di(Methylsulfate) for Direct Determination of Donepezil in Pharmaceutical Formulation and Physiological Serum

Abstract

Donepezil hydrochloride is a cholinesterase inhibitor used in the treatment of Alzheimer's disease, which arises from damage to neurons in brain regions responsible for memory, learning, language, and reasoning. Overdose of donepezil may cause side effects such as fatigue, panic, sweating, vomiting, increased muscle tension, speech difficulties, and involuntary tremors. Therefore, accurate determination of donepezil is of great importance. In this study, a novel potentiometric sensor based on a poly (vinyl chloride) (PVC) membrane incorporating bis (trimethylaminoethylsulfanyl) diaminophthalocyanine di(methylsulfate) (13Pc) as the electroactive ionophore was developed. This work represents the first application of a phthalocyanine derivative as an ionophore for the determination of donepezil. The phthalocyanine derivative 13Pc, with its large conjugated It-system and strong electron-donating groups, enables selective interaction with the cationic form of donepezil. The optimum membrane composition was determined to be 3 % 13Pc, 32 % PVC, 64 % nitrophenyl octyl ether (NPOE), and 1 % potassium tetrakis(4-chlorophenyl) borate (KTpCIPB). The developed sensor exhibited a linear response over the concentration range of 1.0 x 10- 7 to 1.0 x 10- 2 M for donepezil hydrochloride, with a slope of 53.4 mV/decade and a detection limit (LOD) of 1.0 x 10- 7 M. The sensor's working pH range was 2.05 to 7.70, and the average response time was 10 s. The sensor was successfully applied for the determination of donepezil hydrochloride in pharmaceutical tablets and physiological serum samples. Additionally, the environmental sustainability of the developed potentiometric sensor was comprehensively evaluated using EVG (Efficiency, Validation, Greenness) and AGREE (Analytical GREEnness) assessment metrics.