Donepezil—an updated review of challenges in dosage form design

Abstract

Donepezil hydrochloride (DPH) was first launched in 1997 as a choline esterase inhibitor (ChEI). The USFDA has approved it for treatment of Alzheimer's disease since it effectively enhances cholinergic activity by slowing the clearance of acetylcholine in the brain. Although it is the most prescribed drug among ChEIs, a bitter taste with numbness to DPH is a substantial oral administration obstacle, and is a frequently reported adverse event. Several studies have been conducted to overcome this problem by adding sweeteners and flavors, application of physical barriers, preparation of ion exchange resins, and inclusion complexes. Based on the pharmacological activity, the gastrointestinal effect is a frequently reported adverse event. Therefore, novel dosage forms intended to deliver through oral, topical/transdermal, parenteral, and intranasal routes have been designed and developed. In this review, findings from recent studies on DPH are summarized, and the challenges and obstacles of DPH dosage form development are highlighted and discussed