A Randomized, Crossover, Single-Dose Bioequivalence Study of Two Extended-Release Tablets of Donepezil 23 mg in Healthy Human Volunteers under Fasting and Fed States

To assess the bioequivalence of two extended-release tablets of donepezil 23 mg, open label, randomized, single-dose, two-sequence, two-period crossover studies under fasting (n=74) and fed (n=94) conditions in healthy adult human volunteers were conducted. Subjects were randomized to either of the two treatment arms (test or reference) separated by a washout period of 28 days. Blood samples were collected up to 72 h post-dose and plasma samples were analyzed for donepezil using a validated LC-MS/MS method. Pharmacokinetic parameters were derived using a non-compartmental approach. Bioequivalence was evaluated in 69 subjects in the fasting study, and 71 subjects in the fed study. In the fasting study, the 90% CI of Cmax and AUC0-72 were 82.50-90.10 and 92.38-98.60, respectively. Corresponding values in the fed study were 91.82-98.05 and 97.27-100.27. Based on the results, the test product (donepezil) met the US regulatory criteria of bioequivalence relative to the reference product (Aricept(®)) under both fasting and fed conditions.