Current and emerging drug therapies in Alzheimer’s disease: A pathophysiological Perspective

[Display omitted] •Alzheimer's disease (AD), a neurodegenerative disease, can be caused by extracellular accumulation of amyloid plaques and intracellular deposition of neurofibrillary tangles. They also cause other related complications that worsen the condition.•The current study primarily focuses on different properties of targeted and forthcoming drugs for the treatment of Alzheimer’s Disease. Targeted drugs are categorized under various classes of phase studies and mechanism-based therapies.•In this review, various physio-pathological causes of dysfunction in Alzheimer's disease are comprehensively discussed i.e. synaptic impairment, receptor or neurotransmitter-based impairment, cholinergic loss, and amyloid-tau-based symptoms.•Additionally, this study focuses on future targets that could lead to treatment of the main symptoms associated with this disease. Targeted new treatments address epigenetic regulation, oxidative stress, vascular dementia, and more. The analytical and experimental investigation of several targets and biomarkers that help in explaining significant cognitive deficits, covering drug development and precision medicine aimed at different chronic neurodegenerative conditions such as Alzheimer’s disease (AD), Parkinson’s disease, synaptic dysfunction, brain damage from neuronal apoptosis, and other disease pathologies; this served as the foundation for all phase studies. The focus of current therapeutic approaches is on developing humanized antibodies, agonist and antagonist drugs, receptors, signaling molecules, major targeted drug-metabolizing enzymes, and other metabolites to treat neurodegeneration in the AD brain brought on by tau hyperphosphorylation, amyloid plagues, or other cholinergic effects. The five A’s—amnesia, agnosia, aphasia, apraxia, and anomia—are the typical symptoms associated with AD. While the main goal of drug therapeutics studies is modified amino acids acting as pro-drugs, pharmacokinetics studies and trends in evaluating drug-drug interactions focus on interactions between drugs and antibodies, drugs and therapeutic biologics like metabolites, herbs, interleukin-based, and gene silencing mechanism-based. Studies on the biotransformation of xenobiotic compounds and the metabolism of exogenous and endogenous substances are conducted under Phase I, Phase II, and Phase III trials because the pivotal pharmacokinetic properties of drugs, such as absorption, distribution, metabolism, and excretion (ADME), aid in u