Aminoglycosides are scarcely absorbed via the gastro-intestinal tract, and for that reason they are often administered by injection, which is an invasive administration technique. Tobramycin for the treatment of pulmonary infections is currently also nebulised after early inhalation studies with this drug in the 1980s showed promising results against Pseudomonas aeruginosa in Cystic Fibrosis patients. However, nebulisation has many disadvantages. The technique is ineffective, laborious and time-consuming and, thus, a burden to the patient. Dry powder inhalation may be a suitable alternative administration method for this type of drug, but in contrast with many other high dose drugs aminoglycosides have rather inappropriate properties for inhalation. Moreover, it is relatively unknown which, and to what extent, solid state and particle properties of the aminoglycosides (e.g. tobramycin, kanamycin and amikacin) are relevant to dispersion and device retention during inhalation.
