Donepezil hydrochloride is a reversible inhibitor of the enzyme acetylcholinesterase, known chemically as (±)-2, 3-dihydro-5, 6-dimethoxy-2-[[1-(phenylmethyl)-4-piperidinyl]methyl]-1H-inden-1-one hydrochloride[1]. Donepezil hydrochloride is commonly referred to in the pharmacological literature as E2020. It has an empirical formula of C24H29NO3HCl and a molecular weight of 415.96. Donepezil hydrochloride is a white crystalline powder and is freely soluble in chloroform, soluble in water and in glacial acetic acid, slightly soluble in ethanol and in acetonitrile, and practically insoluble in ethyl acetate and in n-hexane[2].

Donepezil hydrochloride is a second-generation highly selective acetylcholinesterase inhibitor developed by the Japanese company Eisai Pharmaceutical Company. It was first marketed in the United States in 1997 for the treatment of Alzheimer's disease[3]. Donepezil is the second drug approved by the FDA for the treatment of Alzheimer's disease. It is a highly selective, long-acting, reversible acetylcholinesterase inhibitor with a piperidine group. Compared with tacrine, donepezil hydrochloride is more selective for neuronal acetylcholinease, has better pharmacodynamics, pharmacokinetics and safety indicators, and is well tolerated[4]. It is an alternative drug to tacrine. Donepezil hydrochloride is a cholinesterase inhibitor. After taking it, patients mainly increase the content of acetylcholine in the synapses that are directly involved in nerve transmission by inhibiting the activity of acetylcholine lipase. Donepezil hydrochloride can Effectively improve patients 'brain function and improve patients' cognitive ability. Currently, donepezil hydrochloride is a commonly used drug in the treatment of mild to moderate senile dementia. Donepezil hydrochloride tablets are suitable for the treatment of memory degeneration of dementia caused by various reasons. Donepezil hydrochloride has the effect of nourishing brain neurons, repairing damaged brain nerves, and can rapidly improve patients' cognitive function and memory[5].

In addition, donepezil has synergistic effects with other cholinesterase inhibitors (such as succinylcholine) taken at the same time, and can antagonize with anticholinergic drugs[6]. Donepezil has a number of advantages: long duration of action: only once a day orally; strong drug efficacy, 3 times more effective than tacrine, high safety, and less adverse drug reactions. Donepezil does not show liver toxicity. The main side effects, such as nausea, diarrhea, muscle cramps and fatigue, are tolerable by most patients[7].

References

[1] Imai A, Ishihama Y, Kajima T, et al. Polymorphs of donepezil hydrochloride and process for production[J]. 1999.

[2] Hydrochloride D. Donepezil hydrochloride in the treatment of senile Alzheimer's disease, early stage[J]. 2014.

[3] Yan, Yi-Dong, Woo, Jong Soo, Kang, Joon Heok. Preparation and Evaluation of Taste-Masked Donepezil Hydrochloride Orally Disintegrating Tablets[J]. Biological & Pharmaceutical Bulletin, 33(8):1364-1370.

[4] YM Greene, Pierre N. Tariot, Heather Wishart. A 12-Week, Open Trial of Donepezil Hydrochloride in Patients with Multiple Sclerosis and Associated Cognitive Impairments[J]. Journal of Clinical Psychopharmacology, 2000, 20(3):350-356.

[5] KOSASA,T. Inhibitory effect of orally administered donepezil hydrochloride (E2020), a novel treatment for Alzheimer's disease, on cholinesterase activity in rats[J]. European Journal of Pharmacology, 2000, 389.