An inhalable powder comprising: (a) an active substance consisting essentially of a compound of formula 1 ##STR00001## wherein X.sup.- is a pharmaceutically acceptable anion; and (b) a physiologically acceptable excipient having an average particle size of 10 .mu.m to 50 .mu.m, processes for preparing the inhalable powder, and methods of administration for the treatment of respiratory complaints, particularly for the treatment of chronic obstructive pulmonary disease (COPD) and asthma.