The invention generally relates to a method for pulmonary delivery of
therapeutic, prophylactic and diagnostic agents to a patient wherein the
agent is released in a sustained fashion, and to particles suitable for
use in the method. In particular, the invention relates to a method for
the pulmonary delivery of a therapeutic, prophylactic or diagnostic agent
comprising administering to the respiratory tract of a patient in need of
treatment, prophylaxis or diagnosis an effective amount of particles
comprising a polycationic complexing agent which is complexed with a
therapeutic, prophylactic or diagnostic agent or any combination thereof
having a charge capable of complexing with the polycationic complexing
agent upon association with the bioactive agent. The particles can
further comprise a pharmaceutically acceptable carrier. The amount of
polycationic complexing agent present in the particles is an amount
sufficient to sustain the release of diagnostic, therapeutic or
prophylactic agent from the particles. For example, the amount of
complexing agent present can be at about 5% weight/weight (w/w) or more
of the total weight of the complexing agent and therapeutic, diagnostic
or prophylactic agent. Release of the agent from the administered
particles occurs in a sustained fashion.