Roflumilast, chemically known as 3-cyclopropylmethoxy-4-difluoromethoxy-N-[3,5-di-chloropyrid-4-yl]-benzamide of Formula-I is an PDE4-inhibitor.

Roflumilast is an effective phosphodiesterase-4-inhibitor (PDE4-inhibitor), which can be used in the treatment of asthma, inflammation, bronchitis, allergy, and osteoporosis, dermatoses and disorders related to immune system, heart and kidney.
Roflumilast is sold under the trademark Daliresp® and is available as an orally administered tablet. It is recommended at 500 mcg once daily.
U.S. Pat. No. 5,712,298 claims Roflumilast and its analogs. This patent also discloses a process for the preparation Roflumilast.
U.S. Pat. No. 6,448,274, PCT Publication No. WO 2005/026095. and PCT Publication No. WO 2004/033430 also disclose processes for the preparation of Roflumilast.
Polymorphism of Roflumilast is not reported in the literature.
One aspect of the present invention provides a stable and industrially scalable novel crystalline form of Roflumilast and an improved process for the preparation of Roflumilast.
USPTO Backgrounds
USPTO Backgrounds