The present invention relates to inhalation formulations of drugs in the form of dry powder for inhalation administration, suitable for the treatment of obstructive diseases of the airways, such as asthma and chronic obstructive pulmonary disease (COPD). In particular, the invention relates to a pharmaceutical composition for inhalation comprising a first powder comprising budesonide or a pharmaceutically acceptable salt thereof, in an amount greater than 5% by weight of said first powder, leucine in an amount from 5 to 70% by weight of said first powder, lactose in an amount from 20 to 90% by weight of said first powder； a second powder comprising formoterol or a pharmaceutically acceptable salt thereof, in an amount greater than 1% by weight of said second powder, leucine in an amount from 5 to 70% by weight of said second powder, lactose in an amount from 20 to 90% by weight of said second powder and a third powder comprising a mixture of a first lactose which has an X50 from 3 to 75 µm, with a second lactose which has an X50 from 1.5 to 10 µm, the content of said first and second lactose in said mixture being respectively from 85% to 96% and from 4% to 15%. Said composition has a fine particle fraction (FPF) greater than 60% and a delivered fraction (DF) greater than 80%.
