Ultrasonic breath actuated respiratory droplet delivery device and methods of use
An ultrasonic droplet delivery device and related methods for delivering precise and repeatable amounts of a substance to a user for respiratory use is disclosed. The ultrasonic droplet delivery device generally comprises a body housing, a mouthpiece having an ejector mechanism, and a fluid cartridge having at least one fluid reservoir. In certain embodiments, the ejector mechanism may comprise at least one ultrasonic actuator and at least one aperture plate with a plurality of openings formed through its thickness for ejecting droplets. The device may further comprise at least one differential pressure sensor configured to activate the ejector mechanism upon sensing a pre-determined pressure change within the device to thereby generate the ejected stream of droplets.
1 . A droplet delivery device comprising:
a mouthpiece positioned at an airflow exit of the device, the mouthpiece comprising one or more air flow entrance ports, an airflow exit opening, an electronically actuated ejector, an ejection chamber, and a fluid transport mating extension;
a fluid cartridge including a volume of fluid and at least one self-sealing stopper, the fluid cartridge disposed within or in fluid communication with the mouthpiece;
a body housing comprising a power source and control board; and
at least one pressure sensor positioned within the mouthpiece or positioned within the housing and in fluid communication with the mouthpiece, the at least one pressure sensor operably coupled to the ejector to generate an ejected stream of droplets upon sensing a pre-determined pressure change within the mouthpiece;
wherein the electronically actuated ejector is in fluid communication with the volume of fluid at a fluid cartridge side of the ejector, the ejector 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 ejection chamber is located adjacent the ejector on the fluid cartridge side of the ejector;
wherein the fluid transport mating extension interfaces with or extends through the self-sealing stopper to create fluid communication between the fluid cartridge and the ejector;
wherein the fluid transport mating extension comprises a wicking element extending through the self-sealing stopper into the volume of fluid and configured to draw liquid from the fluid cartridge toward the ejector by capillary action;
wherein the mouthpiece further comprises at least one vent opening positioned on a fluid side of the aperture plate adjacent the ejector; and
wherein the at least one vent opening is configured to release air displaced by liquid transported by the wicking element to the ejector to reduce air bubble accumulation at the ejector and maintain substantially continuous droplet generation.
2 . The droplet delivery device of claim 1 , wherein at least about 50% of the droplets of the ejected stream of droplets have an average ejected droplet diameter of less than about 6 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 a subject during use.
3 . The droplet delivery device of claim 1 , wherein the one or more air flow entrance ports of the mouthpiece provide an air inlet flow element, and wherein the air inlet flow element and mouthpiece facilitate non-turbulent airflow across an exit side of the aperture plate and provide airflow through the mouthpiece during use.
4 . The droplet delivery device of claim 1 , wherein the at least one vent opening includes a vent filter.
5 . The droplet delivery device of claim 1 , wherein the mouthpiece and ejector are oriented such that the exit side of the aperture plate is perpendicular to the direction of air flow and the stream of droplets is ejected in parallel to the direction of air flow.
6 . The droplet delivery device of claim 1 , wherein the mouthpiece and ejector are oriented such that the exit side of the aperture plate is oriented at an angle relative to the direction of air flow and the stream of droplets is ejected at an angle to the direction of air flow.
7 . The droplet delivery device of claim 1 , wherein the mouthpiece is removably coupled to the fluid cartridge.
8 . The droplet delivery device of claim 1 , wherein at least one of the mouthpiece and fluid cartridge is removably coupled with the body housing.
9 . The droplet delivery device of claim 1 , wherein the fluid cartridge is coupled to the mouthpiece and forms a module that is removably coupled with the housing.
10 . The droplet delivery device of claim 1 , wherein one or more of the plurality of openings of the aperture plate have different cross-sectional shapes or diameters.
11 . The droplet delivery device 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), nickel, nickel-cobalt, nickel-palladium, palladium, platinum, metal alloys thereof, and combinations thereof.
12 . The droplet delivery device of claim 1 , further comprising a wireless communication module.
13 . The droplet delivery device of claim 1 , further comprising one or more sensors selected from the group consisting of an infra-red transmitter, a photodetector, an additional pressure sensor, and combinations thereof.
14 . The droplet delivery device of claim 1 , wherein the self-sealing stopper includes one or more cut openings.
15 . The droplet delivery device of claim 1 , wherein the self-sealing stopper comprises a polymer.
16 . The droplet delivery device of claim 15 , wherein the fluid transport mating extension comprises a polymer.
17 . The droplet delivery device of claim 15 , wherein the self-sealing stopper includes one or more cut openings.
18 . A method for delivering an agent as an ejected stream of droplets in a respirable range to a pulmonary system of a user, the method comprising:
(a) generating an ejected stream of droplets via the droplet delivery device of claim 1 , wherein at least about 50% of the ejected stream of droplets have an average ejected droplet diameter of less than about 6 μm; and
(b) delivering the ejected stream of droplets to the pulmonary system of the user 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 user during use.
19 . The method of claim 18 , wherein the ejected stream of droplets is delivered over a period of time less than about 2 seconds.