Quilostigmine (also known as NXX-066) is an isoquinolinecarboxylate patented by Hoechst-Roussel Pharmaceuticals Inc as a memory enhancer. Quilostigmine acts as acetylcholinesterase inhibitor and studies as a potential drug for treating Alzheimer’s disease. Quilostigmine is well absorbed from the gastrointestinal tract, but the oral bioavailability poor to moderate in rats and dogs because of pre-systemic metabolism. In preclinical studies has demonstrated activity in animal models of memory function. In clinical trials, Quilostigmine was well tolerated in healthy subjects up to a single dose of 64 mg and multiple doses of 60 mg QD for seven days