Therapeutic targets and delivery challenges for Alzheimer’s disease

Table 2 Current market status and ongoing clinical investigation for Alzheimer's disease therapeutics

Active	Mechanism of action	Drug delivery route	Clinical status	Ref.
Approved drugs
Tacrine (Cognex®)	AChEI	Oral	USFDA approved	[205]
Donepezil (Aricept®)	AChEI	Oral	USFDA approved
Galantamine (Razadyne, Reminyl®)	AChEI	Oral	USFDA approved
Rivastigmine (Exelon®)	AChEI	Transdermal patch	USFDA approved
Memantine (Namenda, Axura®, Ebixa®)	NMDA receptor inhibitor, glutaminergic system modifier	Oral	USFDA approved
Drugs under clinical investigation
EHT-0202	α-secretase activator	Oral	Phase 2	[29]
CTS-21166	β-secretase inhibitor	Oral	Phase 2	[35]
MK-0752	γ-secretase inhibitor	Oral	Phase 2	[29,36]
Immunoglobulin	AD immune activity	Intravenous	Phase 2	[170]
Omega-3-fatty acid treatment, nutritional supplement, physical exercise and cognitive stimulation	AD symptomatic management	Oral	Phase 3	[199]
Cerebrolysin and AChEI	Neirotropic, AChEI	Oral	Phase 4	[200,201]
Alzhemed™	Activity Aβ aggregation inhibitor	Oral (dietary supplement)	Phase 3	[206]

USFDA: United States Food and Drug Administration; AChEI: Acetylcholinesterase inhibitors; NMDA: N-methyl-D-aspartate; AD: Alzheimer’s disease.