Droplet delivery device for delivery of fluids to the pulmonary system and methods of use

A breath actuated droplet delivery device for delivering a fluid as an ejected stream of droplets to the pulmonary system of a subject, the device comprising:

• a housing;
• a combination reservoir/ejector mechanism module in fluid communication with the housing for receiving a volume of fluid and generating an ejected stream of droplets;
• the ejector mechanism comprising a piezoelectric actuator and an aperture plate comprising a domed shape, 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;
• at least one differential pressure sensor positioned within the housing;
• the at least one differential pressure sensor configured to activate the ejector mechanism to generate the ejected stream of droplets upon sensing a pre-determined pressure change within the housing when a subject applies an inspiratory breath to an airflow exit side of the housing;
• the ejector mechanism configured to generate the ejected stream of droplets wherein at least about 50% of the droplets have an average ejected droplet diameter of less than about 10 microns, such that at least about 50% of the mass of the ejected stream of droplets is delivered in a respirable range to the pulmonary system of the subject during use.