cPLA2α x β2-adrenergic receptor x GR x M3 receptor

The overall objective is to asses the bronchodilator effect of Tiotropium/Salmeterol/Fluticasone combination delivered via Discair® twice daily as compared with original products Seretide Diskus 500 mcg Inhalation Powder twice daily and Spiriva 18 mcg Inhalation Powder once daily free combination treatment in patients with stable moderate to severe COPD.
Spirometric measurements will be performed totally at 15 different time points at pretreatment and post-treatment (pre-dose, 15. min, 30. min, 1. hr, 2. hr, 4.hr, 8.hr and 12.hr) during the first treatment day and at 16 different time points (15. min, 30. min, 1. hr, 2. hr, 4.hr, 6 hr, 8.hr and 12.hr) during the second treatment day.