AN IMPROVED PROCESS FOR THE PREPARATION OF DONEPEZIL - Patent Application WO/2008/010235 An improved, novel and simple industrial process for the preparation of Donepezil of formula (I) and its pharmaceutically acceptable salts manufactured by the condensation of 5,6-dimethoxy indanone of formula (III) with 1-benzyl-4-piperidine carboxaldehyde of formula (IV) to give 1-benzyl-4-[(5,6-dimethoxy-1-indanon)-2-ylidenyl] methyl piperidine in the presence of base in organic solvents or an aqueous solvent or mixture thereof followed by the reduction carried out using at least one metal borohydride in the presence of catalytic amount of cobalt salts and suitable solvent or mixture thereof. 2. A process for the preparation of donepezil of formula (I) or a pharmaceutically acceptable salt thereof, (I) the process comprising: (a) condensing 5,6dimethoxy indanone of formula (III) (III) with a 1 benzyl4piperidine carboxaldehyde of formula (IV) (IV) to obtain lbenzyl4[(5,6dimethoxylindanon)2ylidenyl] methyl piperidine in the presence of alkali or alkaline earth metal hydroxide in organic solvent selected from the group comprising of dimethoxyethane, 1,3dioxalane, ethylacetate, acetonitrile, tetrahydrofuran; dimethylformamide; diemthylacetamide; dimethylsulfoxide; dioxane; aromatic hydrocarbons, halogenated, carboxylates or an aqueous solvent or mixture thereof. (b) reducing lbenzyl4[(5,6dimethoxylindanon)2ylidenyl] methyl piperidine of formula (II) (H) with metal borohydride in the presence of catalytic amount of cobalt salt in an organic solvents or an aqueous solvent or mixture thereof: and (c) optionally converting formula (I) to its pharmaceutically acceptable salt.