Disclosed is an Inhalable particles comprising a stabilised anhydrous amorphous form of tiotropium with a stabilising agent, which is a sugar derivative selected from the group consisting of a monosaccharide, a disaccharide, an oligosaccharide, a polysaccharide, and a polyalcohol. Also disclosed is where the tiotropium is tiotropium bromide and a method for preparing the inhalable particles.