A method for delivering a therapeutic dose of a bioactive agent to the pulmonary
system, in a single, breath-activated step, comprises administering from a receptacle
enclosing a mass of particles, to a subject's respiratory tract, particles which
have a tap density of less than 0.4 g/cm3 and deliver at least about
50% of the mass of particles. Another method of delivering a therapeutic dose of
a bioactive agent to the pulmonary system, in a single breath, includes administering
from a receptacle enclosing a mass of particles, to a subject's respiratory tract,
particles which have a tap density of at least 0.4 g/cm3 and deliver
at least about 10 milligrams of the bioactive agent. The receptacle can have a
volume of at least 0.37 cm3.
