The present invention provides a dosator for filling a capsule with dry powder when used in an inhalation device comprising: a tube which tapers from the top of the dosator to the bottom of the dosator having an axial passage therein forming an elongate cavity a stationary plunger disposed within the cavity a removable mesh screen having a mesh size that is smaller than the mass median diameter (D50) of the dry powder disposed between the stationary plunger and the bottom of the dosator a dosator chamber defined between the mesh screen and the bottom of the dosator of a predetermined height for receiving powder from a powder source and holding the powder until it is expelled into the capsule at least one vacuum pump operably linked to the dosator and capable of drawing dry powder into the dosator chamber from a powder source, compacting the powder into a slug of powder having a predetermined bulk density at least one source of positive pressure operably linked to the dosator and capable of providing positive pressure to expel the powder slug from the dosator and wherein the dry powder is characterised by a fine particle fraction of 40% or more and the mass diameter of the particles is between 5 micrometers and 18 micrometers.
