ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Donepezil oxidation: complementary chemical and spectroscopic exploration of products, mechanism and kinetics

S. Malini, Kalyan Raj, N. Suresha, and K. S. Anantharaju

Department of Chemistry, B.M.S. College of Engineering, Bangalore, India

E-mail: malinis.chem@bmsce.ac.in

Received: 3 July 2021  Accepted: 11 October 2021

Abstract:

Oxidation is a vital step of drug metabolism and hence a pharmaceutically relevant process. This study explores the potential of Donepezil, a widely used drug against mild to moderately severe Alzheimer's disease, to undergo oxidation using a mild, versatile oxidant Chloramine-T in acidic medium. A first-order dependency of rate on Donepezil and oxidant, fractional-order dependency on acid medium, independency of the rate on ionic concentration and an elevation of rate with increasing dielectric constant are revealed by the kinetic studies. The stoichiometry, thermodynamic properties, rate equation, mechanistic details are outlined, and identification of reaction products is supported by consistent oxidative degradation related UV, IR, ¹H NMR and mass spectroscopic data. The spectroscopic results are in good agreement with theoretical predictions, providing an insight and deepen the understanding of oxidative metabolic pathway of Donepezil.

Keywords: Donepezil; Oxidative degradation; Kinetics; Chloramine-T; Spectrophotometric analysis

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-021-01934-y

Chemical Papers 76 (3) 1457–1470 (2022)