NOVEL POLYMORPHIC FORMS OF l-BENZYL-4-[(5,6-DIMETHOXY-l-INDANONE)-2-YL]METHYL PIPERIDINE [DONEPEZIL] AND PROCESS FOR PREPARING THE SAME

摘要

Disclosed herein novel crystalline polymorphic forms of 1-benzyl-4-(5,6-dimethoxy-1-indanon-2-yl)methylpiperidine (Donepezil) base having higher stability. Said polymorphic forms are designated as Form D and E and characterized by employing analytical tools such as infrared absorption spectrum, X-ray powder diffraction pattern, thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and/or melting point. The present invention also disclosed a process for preparing said polymorphic forms. Further an improved process for preparing polymorphic form B of 1-benzyl-4-(5,6-dimethoxy-1-indanon-2-yl)methylpiperidine (Donepezil) base is also disclosed.