Methods for generating and delivering droplets to the pulmonary system using a droplet delivery device

A method for generating and delivering a fluid as an ejected stream of droplets to the pulmonary system of a subject in a respirable range, the method comprising:

• (a) generating the ejected stream of droplets via an electronically breath actuated droplet delivery device, wherein at least about 50% of the ejected stream of droplets have an average ejected droplet diameter of less than about 5 μm;
• and
• (b) delivering the ejected stream of droplets to the pulmonary system of the subject such that at least about 50% of the mass of the ejected stream of droplets is delivered in the respirable range to the pulmonary system of the subject during use;
• wherein the electronically breath actuated droplet delivery device comprises:
• a housing comprising a mouthpiece located at an airflow exit side of the housing, and a laminar flow element;
• a reservoir disposed within or in fluid communication with the housing for receiving a volume of fluid;
• an electronically actuated ejector mechanism in fluid communication with the reservoir and configured to generate the ejected stream of droplets;
• at least one differential pressure sensor positioned within the housing, the at least one differential pressure sensor configured to activate the ejector mechanism upon sensing a pre-determined pressure change within the housing to thereby generate the ejected stream of droplets;
• the ejector mechanism comprising a piezoelectric actuator and an aperture plate, the aperture plate having a plurality of openings formed through its thickness and the piezoelectric actuator operable to oscillate the aperture plate at a frequency to thereby generate the ejected stream of droplets;
• the laminar flow element located at an airflow entrance side of the housing, wherein the housing, laminar flow element, and mouthpiece are configured to facilitate laminar airflow across an exit side of the aperture plate and to provide sufficient laminar airflow through the housing during use.