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

Abstract

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.

What is claimed: 
     
         1 . A piezoelectric 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 reservoir disposed within or in fluid communication with the housing for receiving a volume of fluid;   an ejector mechanism in fluid communication with the reservoir, 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 an 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 an ejected stream of droplets;   the ejector mechanism configured to generate the ejected stream of droplets wherein at least about 70% of the droplets have an average ejected droplet diameter of less than about 5 microns, such that at least about 70% of the mass of the ejected stream of droplets is delivered in a respirable range to the pulmonary system of a subject during use.   
     
     
         2 . The droplet delivery device of  claim 1 , further comprising 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. 
     
     
         3 . The droplet delivery device of  claim 2 , wherein the ejector mechanism and the surface tension plate are configured in parallel orientation. 
     
     
         4 . The droplet delivery device of  claim 3 , 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. 
     
     
         5 . The droplet delivery device of  claim 1 , wherein the aperture plate comprises a domed shape. 
     
     
         6 . 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), Ni, NiCo, Pd, Pt, NiPd, metal alloys, and combinations thereof. 
     
     
         7 . The droplet delivery device of  claim 1 , wherein one or more of the plurality of openings have different cross-sectional shapes or diameters to thereby provide ejected droplets having different average ejected droplet diameters. 
     
     
         8 . The droplet delivery device of  claim 1 , further comprising a laminar flow element located at the airflow entrance side of the housing and configured to facilitate laminar airflow across the exit side of aperture plate and to provide sufficient airflow to ensure that the ejected stream of droplets flows through the droplet delivery device during use. 
     
     
         9 . The droplet delivery device of  claim 8 , further comprising a mouthpiece coupled with the housing opposite the laminar flow element. 
     
     
         10 . The droplet delivery device of  claim 1 , wherein the ejector mechanism is orientated with reference to the housing such that the ejected stream of droplets is directed into and through the housing at an approximate 90 degree change of trajectory prior to expulsion from the housing. 
     
     
         11 . The droplet delivery device of  claim 1 , wherein the reservoir is removably coupled with the housing. 
     
     
         12 . The droplet delivery device of  claim 1 , wherein 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. 
     
     
         13 . The droplet delivery device of  claim 1 , further comprising a wireless communication module. 
     
     
         14 . The droplet delivery device of  claim 13 , wherein the wireless communication module is a Bluetooth transmitter. 
     
     
         15 . The droplet delivery device of  claim 1 , wherein the device further comprises one or more sensors selected from an infer-red transmitter, a photodetector, an additional pressure sensor, and combinations thereof. 
     
     
         16 . 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 70% of the droplets have an average ejected droplet diameter of less than about 5 microns, such that at least about 70% of the mass of the ejected stream of droplets is delivered in a respirable range to the pulmonary system of the subject during use.   
     
     
         17 . The droplet delivery device of  claim 16 , wherein the domed-shape 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. 
     
     
         18 . The droplet delivery device of  claim 16 , further comprising a laminar flow element located at an airflow entrance side of the housing and configured to facilitate laminar airflow across the exit side of aperture plate and to provide sufficient airflow to ensure that the ejected stream of droplets flows through the droplet delivery device during use. 
     
     
         19 . The droplet delivery device of  claim 16 , further comprising a mouthpiece coupled with the housing opposite the laminar flow element. 
     
     
         20 . A method of filtering large droplets from an aerosolized plume using inertial forces, the method comprising:
 generating an ejected stream of droplets using the droplet delivery device of  claim 1 ,   wherein the ejector mechanism is orientated with reference to the housing such that the ejected stream of droplets is directed into and through the housing at an approximate 90 degree change of trajectory prior to expulsion from the housing; and   wherein droplets having an diameter greater than about 5 μm are deposited on the sidewalls of the housing due to inertial forces, without being carried in entrained airflow through and out of the droplet delivery device to the pulmonary system of the subject.