PROCESS FOR THE PREPARATION OF ROFLUMILAST ANDRELATED IMPURITIES

摘要

ABSTRACT PROCESS FOR THE PREPARATION OF ROFLUMILAST AND RELATED IMPURITIES The present invention provides process for the preparation of roflumilast and related impurities. The invention also provides pure roflumilast and a pharmaceutical compositions comprising therapeutically effective amount of roflumilast and 4-cyclopropylmethoxy-N-(3, 5-dichloro-pyridin-4-yl)-3-difluoromethoxy benzamide (positional isomer of roflumilast), for oral administration to reduce the risk of COPD exacerbations in patients with severe COPD associated with chronic bronchitis.