Methods for generating and delivering droplets to the pulmonary system using a droplet delivery device
A droplet delivery device and related methods for delivering precise and repeatable dosages to a subject for pulmonary use is disclosed. The droplet delivery device includes a housing, a reservoir, and ejector mechanism, and at least one differential pressure sensor. The droplet delivery device is automatically breath actuated by the user when the differential pressure sensor senses a predetermined pressure change within housing. The droplet delivery device is then actuated to generate a stream of droplets having an average ejected droplet diameter within the respirable size range, e.g, less than about 5 μm, so as to target the pulmonary system of the user.
1. 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 a piezoelectric actuated droplet delivery device, wherein at least about 70% 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 70% of the mass of the ejected stream of droplets is delivered to the pulmonary system of the subject during use;
wherein the piezoelectric actuated droplet delivery device comprises:
a housing comprising a mouthpiece located at an airflow exit of the housing, and an airflow inlet flow element positioned at an airflow entrance of the housing;
a fluid ampoule disposed within or in fluid communication with the housing comprising a fluid reservoir for receiving a volume of fluid comprising the therapeutic agent;
an electronically actuated ejector mechanism in fluid communication with the fluid ampoule 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;
wherein the housing, airflow inlet flow element, and mouthpiece are configured to facilitate non-turbulent airflow across an exit side of the aperture plate and to provide sufficient non-turbulent airflow through the device during use.
2. The method of claim 1 , wherein the ejected stream of droplets are subjected to an approximate 90 degree change of trajectory within the piezoelectric actuated droplet delivery device such that droplets having a diameter greater than about 5 μm are filtered from the ejected stream of droplets due to inertial forces, without being carried in entrained airflow through and out of the piezoelectric actuated droplet delivery device to the pulmonary system of the subject.
3. The method of claim 1 , wherein the ejected stream of droplets further comprise droplets having an average ejected droplet diameter of between about 5 μm to about 10 μm.
4. The method of claim 1 , wherein the ejected stream of droplets comprises a therapeutic agent for the treatment of a pulmonary disease, disorder, or condition.
5. The method of claim 1 , wherein the aperture plate of the piezoelectric actuated droplet delivery device comprises a domed shape.