The invention relates to the delivery of high doses of active pharmaceutical compds. via inhalation for the treatment of pulmonary diseases. A pharmaceutical formulation in the form of a powder suitable for inhalation comprises one or more active pharmaceutical ingredients, such as an antibiotic, a mucolytic agent and/or a buffer, wherein the formulation is free of carrier. A powder formulation comprising doxycycline monohydrate combined with sodium citrate filled into TwinCap devices was exemplified.