A method for the preparation of respirable zafirlukast monohydrate particles comprises the steps of preparation of an aqueous suspension of amorphous zafirlukast； size-reduction with conversion of the suspended zafirlukast into crystalline monohydrate nanoparticles； and isolation of the crystalline zafirlukast in the form of a dry powder. Also provided are zafirlukast respirable particles characterized by comprising crystalline monohydrate zafirlukast. Pharmaceutical compositions comprising the particles are also disclosed, as is the use of the particles or compositions for the treatment of respiratory diseases.
