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 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.
2. The method of claim 1 , wherein the ejected stream of droplets are subjected to an approximate 90 degree change of trajectory within the electronically breath 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 electronically breath actuated droplet delivery device to the pulmonary system of the subject.
3. The method of claim 2 , wherein the filtering of droplets having a diameter greater than about 5 μm increases the mass of the ejected stream of droplets delivered to the pulmonary system of the subject during use.
4. The method of claim 1 , wherein the ejected stream of droplets further comprise at least a portion of droplets having an average ejected droplet diameter of between about 5 μm to about 10 μm.
5. 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.
6. The method of claim 1 , wherein the electronically breath actuated droplet delivery device further comprises a surface tension plate between the aperture plate and the reservoir, wherein the surface tension plate is configured to increase contact between the volume of fluid and the aperture plate.
7. The method of claim 1 , wherein the aperture plate of the electronically breath actuated droplet delivery device comprises a domed shape.
8. The method of claim 6 , wherein the ejector mechanism and the surface tension plate are configured in parallel orientation therebetween.
9. The method of claim 8 , wherein the surface tension plate is located within 2 mm of the aperture plate so as to create sufficient hydrostatic force to provide capillary flow between the surface tension plate and the aperture plate.
10. The method of claim 1 , wherein the aperture plate is composed of a material selected from the group consisting of poly ether ether ketone (PEEK), polyimide, polyetherimide, polyvinylidine fluoride (PVDF), ultra-high molecular weight polyethylene (UHMWPE), Ni, NiCo, Pd, Pt, NiPd, metal alloys, and combinations thereof.
11. The method of claim 1 , wherein one or more of the plurality of openings of the aperture plate have different cross-sectional shapes or diameters to thereby provide ejected droplets having different average ejected droplet diameters.
12. The method of claim 1 , wherein the laminar flow element is located opposite the mouthpiece located at the airflow exit side of the housing.
13. The method of claim 1 , wherein the mouthpiece is removeably coupled with the housing.
14. The method of claim 1 , wherein the reservoir is removably coupled with the housing.
15. The method of claim 1 , wherein the reservoir is coupled to the ejector mechanism to form a combination reservoir/ejector mechanism module, and the combination reservoir/ejector mechanism module is removably coupled with the housing.
16. The method of claim 1 , wherein the electronically breath actuated droplet delivery device further comprises a wireless communication module.
17. The method of claim 1 , wherein the electronically breath actuated droplet delivery device further comprises one or more sensors selected from an infra-red transmitter, a photodetector, an additional pressure sensor, and combinations thereof.
18. The method of claim 1 , wherein the laminar flow element comprises an array of openings formed there through and configured to increase or decrease internal pressure resistance within the droplet delivery device during use.