Abstract:
Devices and methods for nebulizing a fluid are described. A replaceable fluid assembly may include a reservoir and a fluid cartridge. The reservoir may be detachable from the fluid cartridge and may be assembled by the prior prior to loading into the nebulizing device.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention is directed to the field of devices for nebulizing fluids. In particular, the nebulizing device of the present invention is directed to an inhalation device for delivering a nebulized fluid. 
     The present invention is also directed to devices and methods for storing and delivering fluids to be nebulized. 
     SUMMARY OF THE INVENTION 
     The present invention provides a nebulizing device which is preferably a hand-held nebulizing device for inhalation of the nebulized fluid. The device has a mouthpiece through which the user inhales the nebulized fluid. The nebulizing element is preferably a vibrating element with holes through which the fluid is ejected although other suitable nebulizing elements may be used without departing from numerous aspects of the invention. 
     The fluid is held in a container which holds a number of doses of the fluid. The container delivers the fluid to a reservoir. The reservoir is designed to minimize the residual volume in the reservoir. The inner surface of the reservoir is preferably hydrophobic to encourage fluid to flow downward to the nebulizing element. The reservoir is also preferably tear-drop shaped and has a smooth inner surface which is free of seams and corners to further encourage downward flow. The container and reservoir may be replaced independently or at the same time. The reservoir and container may also be a single unit or may be separate units mounted to the device by the user. 
     The reservoir also has a collection area located adjacent to the vibrating element where a final volume of fluid accumulates. The final volume is drawn over the holes in the vibrating element when the vibrating element is vibrated thereby reducing the residual volume. The reservoir is also designed so that the nebulizing element is positioned at a relatively low hydrostatic position when the nebulizer is positioned in a preferred operating orientation. For example, the nebulizing element may be positioned so that less than 25%, and even less than 10%, of the volume of the reservoir is positioned below the nebulizing element. 
     The reservoir also has one or more vent holes for smooth fluid delivery into the reservoir during filling and out of the reservoir when the fluid is being nebulized. The vent hole is sized to prevent the fluid from escaping therethrough. 
     The fluid path between the container and reservoir includes a valve which prevents contamination of the container and fluid path. The valve maintains the sterility of the container so that the container does not need to be pierced a number of times as may otherwise be necessary. The valve may be positioned at a wall of the reservoir so that the valve isolates the entire fluid path together with the container. 
     Various aspects of the present invention are also directed to a container. The container is similar to a standard vial with the addition of a specialized connector. The connector mates with the nebulizing device and, in another aspect, may mate with the reservoir as well. The connector has a protrusion which engages an L-shaped slot in the device for a bayonette-type connection. The connector also has a number of tabs or hooks which engage the reservoir to lock the reservoir to the container. 
     The mouthpiece may be separable from the rest of the housing. The nebulizing element may also be contained within the mouthpiece so that the nebulizing element may be cleaned along with the mouthpiece. The mouthpiece also has a port which receives a pressure sensing conduit. The pressure sensing conduit leads from a mouthpiece chamber to a pressure sensor. The pressure sensor is used for breath-actuation of the device by sensing the drop in pressure when the user inhales on the mouthpiece. 
     These and other aspects of the invention are disclosed and described in the following description, drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         FIG. 1  shows a nebulizer. 
         FIG. 2  shows a fluid assembly formed by a reservoir and a container. 
         FIG. 3  shows the nebulizer with a mouthpiece and fluid assembly removed. 
         FIG. 4  show the fluid assembly mounted to the nebulizer with the mouthpiece removed. 
         FIG. 5  shows the container. 
         FIG. 6  is a perspective, cross-sectional view of the reservoir. 
         FIG. 7  is the perspective view of device with the mouthpiece removed. 
         FIG. 8  is a perspective view of  FIG. 7  with the mouthpiece attached to the housing. 
         FIG. 9  is a cross-sectional view of the nebulizer with the reservoir empty. 
         FIG. 10  is a cross-sectional view of the nebulizer with the reservoir filled with a volume of fluid. 
         FIG. 11  shows the nebulizing element delivering the nebulized fluid through the mouthpiece. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1-8 , a nebulizing device  2  is shown. The nebulizing device  2  is preferably a hand-held inhalation device although various aspects of the invention may be practiced with any other nebulizing device or inhalation device. The nebulizing device  2  has a housing  4  which includes a mouthpiece  6  through which the user inhales a nebulized fluid. The fluid is nebulized by a nebulizing element  8  and the nebulized fluid is entrained in air drawn into the device  2  through air inlet openings  10  in the mouthpiece  6 . 
     The fluid to be nublized is a container  12 , such as vial  15 , which preferably holds a number of doses of the fluid. The container  12  and replaced as necessary. The user selects a dose size or amount and delivers the dose from the container  12  to a reservoir  14 , which holds fluid. The reservoir  14  may be removed and replaced together with or separate from the container  12  as explained below. 
     The container  12  has a piston  16 , which is moved by dosing mechanism  18  to dispense a volume of the fluid. The dosing mechanism  18  may be any suitable dosing mechanism such as the dosing mechanism for insulin pen mechanisms. The dosing mechanism  18  is operated with a dosing control  20  which the user operates to select and deliver a quantity of fluid to the reservoir  14 . the housing  4  has a window to view the amount of fluid in the container  12 . 
     The container  12  has a body  22  similar to a standard vial. The container  12  does differ from a standard vial in that the container  12  has a connector  23 , such as a collar  24 , which mates with the reservoir  14  and the nebulizer  2 . The connector  23  helps to prevent the user from loading the wrong fluid into the nebulizer  2 . To this end, the connector  23  has a bayonet-type connection with the nebulizer  2 . The connector  23  has three projections  26  extending from a cylindrical body  28 . The projections register and slide within L-shaped  30  slots in the nebulizer  2 . The container  12  is loaded into the device  2  by pushing downward and then rotating the collar  24  to secure the collar  24 , and therefore container  12 , to the device  2 . The slots  30  may have a raised-portion or detent to lock the projection in the slot  30 . The position, size, spacing and orientation of the projections  26  and corresponding slots  30  may be altered for different fluids to prevent use of the improper fluid. The device  2  may also have a sensor  32  which detects proper engagement of the projection  26  within the slot  30  before the device  2  will dispense fluid. The container  12  may, of course, have any suitable connection with the nebulizer  2  which helps to prevent use of the improper fluid. 
     The container  12  also locks together with the reservoir  14  to provide a secure engagement with the reservoir. When the container  12  is mounted to the reservoir  14 , a needle  40  pierces the container  12 . The container also has three tabs or hooks  42  which lock together with mating connectors on the reservoir  14 . The tabs  42  are located about 120 degrees apart and each have a recess  44  and a shoulder  46  which engage complemtary features on a connector  43  on the reservoir  14 . The container  12  and reservoir  14  may, of course, mount to one another in any other suitable manner and the features may be altered for different fluids. 
     The container  12  and reservoir  14  form a fluid assembly  48 . The container  12  is preferably mounted to the reservoir  14  by the user immediately before loading the container  12  and reservoir  14 . Alternatively, the container  12  and reservoir  14  may be loaded sequentially. For example, the container  12  could be mounted to the device  2  followed by mounting the reservoir  14  to the container  12 . The fluid assembly  48  may also be provided as a single unit which the user replaces all at once. 
     The reservoir  14  has an opening  50  which delivers the fluid to the nebulizing element  8 . The opening  50  is oriented to form a feed angle of about 5 to 30 degrees, and may be about 15 degrees, relative to the longitudinal axis L of the container  12  as defined by the container  12  body. The opening  50  also may have a diameter of about 0.05 to 0.25 inch and may be about 0.15 inch. The opening  50  size and feed angle provide smooth delivery of the fluid from the reservoir  14  to the nebulizing element  8  particularly when the nebulizing element  8  is oriented somewhat upright. 
     The fluid travels along a fluid path  52  between the container  12  and reservoir  14 . The fluid path  52  includes the needle  40  and a channel leading from the needle  40  to the reservoir  14 . The fluid path  52  may, of course, be formed in any other manner including a simple lumen or tube extending between the container  12  and reservoir  14 . Furthermore, the fluid coupling between the container  12  and reservoir  14  may be any other suitable coupling other than needle  40 . 
     The fluid path  52  also includes a valve  54  which prevents contamination of the container  12 . The valve  54  eliminates the need to pierce the container  12  a number of times as may be necessary to maintain sterility if the valve were not provided. The valve  54  may be a one-way valve such as a slit valve, ball valve or duckbill valve. The valve  54  is preferably positioned to protect the entire fluid path between the container  12  and reservoir  14 . To this end, the valve  54  may be positioned at the end of the fluid path  52  such as at a wall  56  of the reservoir  14 . The valve  54  may also be positioned at a relatively low hydrostatic position relative to the reservoir  14  such that less than 25% of the reservoir  14 , and more preferably less than 10%, is positioned hydrostatically below the valve  54 . In this manner, the residual fluid volume in the reservoir  14  may be reduced since the valve  54  position can reduce the wetted surface of the reservoir  14  as compared to a valve positioned to dispense the fluid at a higher position in the reservoir. Of course, the valve  54  may be positioned at an elevated position in the reservoir  14  without departing from the invention. The valve  54  may also direct the fluid at the nebulizing element  8 . The valve  54  may direct a stream of fluid at the nebulizing element  8  so that air in the reservoir  14  near the nebulizing element  8  is actively removed. A problem which can occur when delivering fluid to the nebulizing element is that air can be trapped near the nebulizing element which can inhibit proper functioning of the device. The orientation of the valve  54  and the ability of the valve  54  to deliver a stream of fluid together reduce the risk of trapping air around the nebulizing element  8 . 
     The reservoir  14  has an inner wall  71  that has a tear-drop shape and is substantially free of corners, seams and edges to encourage fluid drainage. The reservoir  14  has a backwall  60  which forms an angle of about 20 to 70 degrees with respect to horizontal when the device is held in a preferred operating orientation. The inner wall  62  of the reservoir  14  is also preferably hydrophobic, but may be hydrophilic depending upon the application and particular fluid, to further reduce the residual volume. The reservoir  14  may also have a relatively small volume to minimize the surface area of the reservoir  14 . The tear-drop shape, smooth interior wall, angled backwall  60  and hydrophobic surface all encourage liquid in the reservoir  14  to flow downward toward the nebulizing element  8  thereby minimizing the residual fluid volume. 
     The nebulizing element  8  may be angled away from the reservoir  14  at an angle of about 0-45 degrees relative to vertical and may be about 15 degrees when the device is in the preferred operating orientation. The reservoir  14  may be made in any suitable manner and with any suitable materials. For example, the reservoir  14  may be made out of polypropylene and formed by injection molding. The nebulizing element  8  may be oriented in any other manner and may be any type of nebulizing element. 
     The mouthpiece  6  may be removable to load and remove the container  12  and/or reservoir  14 . Removal of the mouthpiece  6  also permits cleaning of the mouthpiece  6  and nebulizing element  8 . The nebulizing element  8  may be cleaned or removed after each use or at any predetermined interval such as, for example, after a predetermined number of containers  12  and/or reservoirs  14  have been used. The mouthpiece  6  or nebulizing element  8  may even be removed and replaced with each container  12  or assembly  48 . The mouthpiece  6  may be mounted with a suitable connection such as a snap-fit connection or latch with the rest of the housing. 
     The mouthpiece  6  has the air inlet opening  10 , preferably a number of openings  10 , which permit introduction of air to entrain the nebulized fluid for inhalation by the user. The nebulized fluid is entrained in the air entering a mouthpiece chamber  63  and the nebulized fluid is inhaled by the user when the user inhales on the mouthpiece. 
     The nebulizing element  8  may include a vibrating assembly  80 . The vibrating assembly  80  includes a piezoelectric element  82  mounted to a substrate  84 . The substrate  84  may be cup-shaped  86  or may have any other suitable shape such as a flat-ring or plate. A vibrating element  88  with a number of holes  90  is mounted to the substrate  84 . The vibrating element  88  is preferably dome-shaped and the holes  90  may be tapered. The vibrating element  88  and assembly  80  may, of course, be any other suitable element such as a flat-plate, thin mesh or flexible membrane without departing from the scope of the invention. Furthermore, various aspects of the invention may be practiced independent of the particular nebulizing method and device. 
     The substrate  84  is coupled to the mouthpiece directly or by a mounting element  92  which secures the vibrating assembly  80  to the housing  4  and specifically the mouthpiece  6 . The vibrating assembly  80 , via the mounting element  92 , is coupled to the housing  4  by a flexible connection  94  such as a resilient connection  95 . The connection  94  may be formed in part by a spring, foam, or elastomeric element disposed between the vibrating assembly  80  and housing  4 . In the particular embodiment shown, an elastomeric element  96  having an oval cross-section is shown although a C-shaped cross-section or other suitable shape may be used such as U-shaped. The flexible or resilient connection  94  can reduce dampening of the vibrating assembly as compared to rigid connections with the mouthpiece or housing  6 . 
     The resilient connection  95  also provides a modest closing force on a fluid seal  98  between the nebulizing element  8  and reservoir  14 . The closing force created by the resilient connection  95  helps to prevent fluid from leaking out of the seal  98  between the reservoir  14  and nebulizing element  8 . The seal  98  is formed by a sealing element  100 , such as an o-ring on the mounting element  92 , and a complementary sealing element  102 , such as a groove on the reservoir  14 . The connection  94  naturally biases the sealing elements  100 ,  102  together in that the connection  94  is slightly compressed when the reservoir  14  is mounted. The proper alignment of the reservoir  14  is achieved when the mouthpiece  6  registers with the rest of the housing  4 . 
     The mounting element  92  may also engage the vibrating assembly  80 , such as the vibrating element  88 , and direct fluid to the vibrating element  88 . The mounting element  92  may engage the vibrating element  88  with any suitable connection. For example, the mounting element may be glued to the vibrating element  88  or may have an o-ring which engages the vibrating element. As mentioned above, the vibrating element is generally oriented within 45 degrees of vertical, and preferably about 15 degrees, during operation but may be oriented at any other angle without departing from the invention. 
     The device  2  is preferably breath-actuated in any suitable manner. In the preferred embodiment, a pressure sensor  110 , such as a pressure transducer  112 , measures pressure in the mouthpiece chamber  114  so that when the user inhales on the mouthpiece  6  the sensor  110  detects the pressure drop and triggers the nebulizing element  8  at a trigger pressure. The pressure sensor  110  may be mounted to the mouthpiece  6  but is preferably mounted to the body of the device  2 . A pressure sensing conduit  116  extends to a rear chamber  118  of the device  2  where the pressure sensor  110  is mounted. A pressure sensing port  118  in the mouthpiece  6  receives the conduit  116  to provide pressure communication between the mouthpiece chamber  63  and pressure sensor  110  via the conduit  116 . 
     Operation of the device is now described. The user detaches the mouthpiece and loads the fluid assembly into the device. The fluid assembly may be formed by the container and reservoir which are attached together by the user or mounted in sequence to the device. Once the container and reservoir are attached together, the interlocking feature may prevent disassembly and thus prevent improper usage of the device and parts thereof. The device may be primed in any suitable manner. For example, a volume of fluid equal to or just larger than the fluid path may be delivered when the container is loaded or when the first dose is delivered from a particular container. Alternatively, fluid may simply be delivered from the container until fluid is sensed in the reservoir. 
     When the user is prepared to inhale the nebulized fluid, the user operates the dosing controls to select and deliver a volume of fluid from the container to the reservoir. The dosing mechanism moves the piston to move fluid through the fluid path, out the valve and into the reservoir as shown in  FIGS. 9 and 10 . The user then operates the device by simply inhaling on the mouthpiece. When the user inhales, the pressure sensor detects the drop in pressure until the trigger pressure is reached at which time the nebulizing element is activated. Air is drawn into the chamber through the inlet openings and the nebulized fluid is entrained in the air which is inhaled by the user. The device continues to nebulize fluid while the user continues to inhale. This process is repeated until all of the solution has been nebulized. The device may also measure, detect or calculate when all of the fluid in the reservoir has been nebulized in any suitable manner. For example, the device may deactivate the nebulizing element by measuring the resonant frequency of the vibrating element before fluid is delivered and deactivating the nebulizing element just before the dry resonant frequency is reached again. 
     The invention has been described with respect to various specific embodiments but it can be appreciated that various modifications may be made without departing from the scope of the invention.