The present invention relates to drug formulations in dry powder form for administration by inhalation and indicated for the treatment of obstructive airway syndromes such as asthma and chronic obstructive pulmonary disease (COPD). In particular, the invention relates to an inhalable pharmaceutical composition comprising a first powder consisting of budesonide, or one of its pharmaceutically allowable salts, in a quantity greater than 5% w/w of said first powder, leucine in a quantity in the range of 5 to 70% w/w of said first powder, and lactose in a quantity in the range of 20 to 90% w/w of said first powder； a second powder consisting of formoterol, or one of its pharmaceutically allowable salts, in a quantity greater than 1% w/w of said second powder, leucine in a quantity in the range of 5 to 70% w/w of said second powder, and lactose in a quantity in the range of 20 to 90% w/w of said second powder； and a third powder consisting of leucine in a quantity in the range of 5 to 70% w/w of said third powder, and lactose in a quantity in the range of 20 to 90% w/w of said third powder. Said composition has a fine particle fraction (FPF) greater than 60% and a delivered fraction (DF) greater than 90%.
