The enzyme PDE-4 is found mainly in inflammatory cells, and Roflumilast acts as a selective, long-acting inhibitor of PDE-4. It has anti-inflammatory effects and is under development as an orally administered drug for the treatment of inflammatory conditions of the lungs such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease (COPD). In vitro studies show that roflumilast inhibits the production of inflammatory mediators in a variety of human immune cells, suggesting a role for reducing COPD-related inflammation. Roflumilast is also found to decrease glucose levels in patients with newly diagnosed type-2 diabetes since diabetes is an important comorbidity associated with COPD.