Paper Title
In vitro Assessment of Acetylcholinesterase Inhibitory Activity using Combination of Synthetic Drugs

Abstract
Cholinesterase inhibitors (Donepezil) and N-methyl D-aspartate (NMDA) receptor antagonists (Memantine) are the most widespread medication that use to control Alzheimer's disease. Donepezil suppresses the activity of acetylcholinesterase (AchE) that increases the activity of acetylcholine, which leads to improved cognitive function. In addition to that, NMDA receptor antagonists control glutamatergic receptors of the neurons, which are involved in synaptic plasticity, neuronal growth, and neuronal differentiation. By doing so, it enhances patients' cognition, learning, and memory. In this study, Donepezil and Memantine are used in combination to observe acetylcholinesterase inhibitory activity compared to Donepezil monotherapy. Modified Ellman's method was incorporated in this experiment to determine the activity of these medications. The maximum inhibitory activity is obtained 92.59% for Donepezil, a dose of 100 μg/ml. A maximum of 71.25% inhibition is accepted in combination therapy (Donepezil: 75 μg + Memantine: 25 μg) of the total 100 μg/ml dose. It is the first study where we used Memantine in combination with Donepezil to observe the acetylcholinesterase inhibitory effect. Further studies at different doses will help to establish whether combinations of these drugs are beneficial for the patients or not. Keywords - Acetylcholinesterase inhibitor, Donepezil, Memantine, Combination Therapy.