Patent Publication Number: US-2009235930-A1

Title: Unit dose dry powder inhaler

Description:
This application is a Continuation of U.S. patent application Ser. No. 11/130,959, filed May 17, 2005, and now pending, which claims priority to U.S. Provisional Application No. 60/575,138 filed May 28, 2004. 
    
    
     BACKGROUND OF INVENTION 
     The field of the invention is dry powder inhalers. 
     Certain medicines may be inhaled in dry powder form directly into the lungs. Inhalation bypasses the digestive system and avoids any potential metabolic inactivation or destruction of the medicine by the digestive system. Inhalation can also provide very rapid onset of the effect of the medicine. Inhalation may also allow smaller doses to be used to achieve the same desired results as orally ingested medicines. In other cases, it provides a delivery technique for medicines that display unacceptable side effects when taken by other methods. In addition, inhalation also avoids the potential risks of injection to both medical care givers and patients. 
     Various inhaler designs have been proposed, to allow dry powder medicines to be inhaled. Most of these inhalers are metered dose inhalers or multiple dose dry powder inhalers. Metered dose inhalers dispense a suspension of powder particles in a compressed propellant gas. Multiple dose dry powder inhalers generally repeatedly dispense individual doses from a bulk powder reservoir, or from a blister disk, cassette or tape. However, certain medicines, such as certain peptides or proteins, or medicines such as vaccines, antidotes, etc., are generally taken by a patient infrequently or may even be taken only once. Metered dose inhalers and multiple dose dry powder inhalers are not intended or well designed for one-time use, to deliver a single dose. These types of inhalers are typically too bulky, costly, inefficient, or difficult to use, when only a single dose is desired, and where the inhaler can be and its drug/dose unit practically discarded after use, in an environmentally acceptable way. 
     Several unit dose inhalers, intended for one-time use, have been proposed. However, they have not achieved widespread use. Disadvantages remain with unit dose inhalers relating to powder storage, dose uniformity, dispersion performance, ease of use, cost, and other factors. Accordingly, there is a need for an improved inhaler for efficiently providing a single dose of a powdered drug. 
     It is an object of the invention to provide such an improved dry powder inhaler. 
     SUMMARY OF THE INVENTION 
     A unit dose dry powder inhaler uses a dose unit containing a single dose of a pharmaceutical powder in a blister or other sealed container. As the dose unit is moved into the inhaler, the container is automatically opened, releasing the dose of powder for inhalation. This inhaler design is simple, compact, inexpensive and yet efficient. 
     In one aspect, the inhaler has a dispersion chamber including one or more beads. Upon inhalation, the beads move rapidly within the dispersion chamber to help disperse the powder into air. Accordingly, the powder is effectively dispersed via air flow resulting from inspiration of the user. While preferred, the beads are not an essential element. 
     In another aspect, a dose unit or assembly has a tab pivotably supported within the plane of a frame. The tab is separated from the frame by a slot. A container, such as a blister containing a single dose of powder medicine has a bottom surface or base layer attached to the tab. The base layer also extends over the slot and is attached to areas of the frame. As dose unit is moved typically linearly, within the inhaler, the tab pivots out of the plane of the frame. This shears or tears open the base layer releasing the powder into the inhaler. As a result, the dose of powder remains sealed within the blister or container, until moments just before inhalation. The disadvantages of prolonged exposure of the powder to the environment, such as oxidation, particle size growth, caking, etc. are reduced or avoided. In addition, the inhaler with the dose unit is very easy to use as it requires only a single simple push-button type of movement to open the container. 
     Other features and advantages are described below. The invention resides as well in subcombinations of the features shown and described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, wherein the same reference number indicates the same element in each of the views: 
         FIG. 1  is a rear perspective view of a unit dose dry powder inhaler. 
         FIG. 2  is a front and side perspective view of the inhaler shown in  FIG. 1 . 
         FIG. 3  is a front view of the inhaler shown in  FIG. 1 , in a packaged or storage position. 
         FIG. 4  is a front view of the inhaler of  FIG. 1 , in a ready for use condition. 
         FIG. 5  is a perspective view of the mouthpiece plate and dose unit shown in  FIGS. 1 and 2 . 
         FIG. 6  is a perspective view similar to  FIG. 5 , with the dose unit removed for clarity of illustration. 
         FIG. 7  is a perspective view of the base plate shown in  FIG. 1 , and also showing the reverse side of the dose unit shown in  FIG. 5 . 
         FIG. 8  is a perspective view similar to  FIG. 7 , with the dose unit removed for clarity of illustration. 
         FIG. 9  is a schematic illustration of the inhaler as shown in  FIG. 3 . 
         FIG. 10  is a schematic illustration of the inhaler as shown in  FIG. 4 . 
         FIG. 11  is a bottom view of the dose unit shown in  FIGS. 5 ,  7 ,  9  and  10 . 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     As shown in  FIGS. 1-4 , a unit dose dry powder inhaler  10  has a base or bottom plate  12  attached to a top or mouthpiece plate  14 , to form an inhaler housing  15 . 
     Referring now also to  FIGS. 5-8 , a dispersion chamber  22  is formed within the housing  15 , by a base chamber wall or section  28  on the base plate  12 , together with a top chamber wall or section  30  on the top plate  14 . One or more beads  24  are contained within the dispersion chamber  22 , as described in U.S. Pat. No. 6,427,688, and U.S. Published Patent Application No. 2001/0027790A1, both incorporated herein by reference. A cylindrical dose tube  32  is formed within the housing  15 . A tapered or conical area  35  is optionally provided at the inner end of the dose tube  32 . A chamber inlet passageway or tube  26  extends between and connects the dose tube  32  into the dispersion chamber  22 . A raised rim  33  may be provided on one or both of the base plate  12  and the top plate  14  surrounding the dose tube  32 , the chamber inlet passageway  26 , and/or the dispersion chamber  22 , for ease of manufacture, or to help confine air flow within these spaces, or both. 
     Referring to  FIGS. 1 ,  3  and  4 , a chamber tube  18  extends from the dispersion chamber  22  up through the mouthpiece  16 . Sheath air openings  20  are optionally provided in the mouthpiece  20 . A toroidal sheath air opening  21  may also be provided surrounding the chamber tube  18 . 
     Turning now to  FIGS. 5 ,  7  and  9 - 11 , a dose unit, generally designated  36 , has an end cap or button  38  on a plate  40 . An alignment ring or sector  42  extends outwardly from the plate  40 , similar to the cap  38 . A tab  48  is positioned within a tab slot or opening  58  in the plate  40 . The tab  48  is supported on a pair of pivot pins or supports  56 , allowing the tab  48  to pivot relative to the plate  40  under nominal force. A second or lever section  52  of the tab  48  is joined to a first or blister section  50  of the tab  48  at an obtuse angle, e.g., 100-160 degrees, 125-145 degrees, or about 130 degrees. The intersection of the lever section  52  and the blister section  50  of the tab  48  is advantageously located at or adjacent to the pivot axis  54  extending through the pivot pins  56 . 
     Referring to  FIGS. 9-11 , a blister  46  containing a dry powder  47  is provided on the tab  48 . The blister  46  includes a conical or domed top surface attached to a flat seal layer  44 . The seal layer  44 , typically a metal foil, is adhered or otherwise attached onto the tab  48 , as described in U.S. Pat. No. 5,622,166 and U.S. Pat. Des. 384,283, both incorporated herein by reference. The central area of the seal layer  44  is attached to the blister section  50  of the tab  48 , with the seal layer  44  of the blister  46  also overlying the tab slot or opening  58  and attached to the plate  40 , as shown in dotted lines in  FIG. 11 . 
     In use, the inhaler  10  is typically provided within an envelope or package  11  in an assembled and ready to use condition. A dose unit assembly  36  is preinstalled within the chamber tube  18  of the housing  15 , as shown in  FIG. 3 . The lever section  52  of the tab  48  is adjacent to, or in light contact with, the tab ramp  34 , as shown in  FIGS. 5-7  and  9 . When the user is ready to inhale a dose of medicine  47 , the user pushes on the end cap  38  of the dose unit  36 . The dose unit  36  slides within the chamber tube  18 , from the position shown in  FIGS. 3 and 9 , to the position shown in  FIGS. 4 and 10 . As this occurs the lever section  52  moves against the tab ramp  34 . The tab  48  pivots about the pivot line  54 , or about the pivot pins  56 . The seal layer  44  is sheared out from the bottom of the blister  46 , as the blister section  50  of the tab  48  pivots downwardly. This movement releases the powder  47  into the inside or front end of the chamber tube  18 . 
     The user then places the mouthpiece  16  into the mouth and inhales. Air flows through the chamber tube  18  entraining and carrying the powder  47  through the chamber inlet  26  and into the dispersion chamber  22 . The beads  24  in the dispersion chamber  22  move rapidly within the chamber, helping to disperse the powder  47 . The dispersed powder/air mixture flows out of the dispersion chamber  22  into the chamber tube  18 , and into the user&#39;s lungs. Sheath air is optionally provided via sheath air passageways  20  or  21 , to help reduce deposition of powder particles on or in the mouthpiece  16 , or the user&#39;s mouth and throat. Improved deposition of powder  47  into the user&#39;s deep lung is achieved. 
     As shown in  FIGS. 4 and 10 , a cap recess  60  may be provided in the housing  15 , to reduce the potential for inadvertent pressing of the dose unit into the dose tube, during packaging, shipping, storage or handling. A detent or latching or locking device may optionally be provided on the dose unit  36 , to prevent its removal from the housing  15 , either before use, in the position shown in  FIG. 9 , or after use, in the position shown in  FIG. 10 . Alternatively, for certain medicines or dosing regimens, the dose unit may be dimensioned so that it can be easily pulled out of the housing, removed, and replaced with a new dose unit. This allows for repeated use of the inhaler. 
     The dose unit  36  is preferably molded of a plastics material, for ease of manufacture, and with the pivot pins  56  molded in place. 
     The alignment ring or sector  42  helps to center and align the dose unit  36  within the chamber tube  18 . Keying features may also be provided on the dose unit  36 , to ensure proper angular alignment of the dose unit  36  within the chamber tube  18 , so that the lever section  52  of the tab  48  properly aligns with and contacts the tab ramp  34  during use. As shown in dotted lines in  FIG. 11 , the dose unit  36  may include one or more wings  70  which are permanently broken, deflected, bent, or sheared off, when the dose unit  36  is pressed into the dose tube  32 . If the used dose unit is removed from the dose tube  32 , the wings  70  provide a visual indication that the dose unit is used and should be discarded. The potential for inadvertent attempts to use an already used and empty dose unit are therefore reduced. 
     Although the housing  15  is shown as a two-piece construction including the base plate  12  and the top plate  14 , single piece or multiple piece housing designs are also feasible. In addition, while the housing  15  is described here as formed by plates  12  and  14 , the housing  15  may of course have other shapes and construction characteristics. Similarly, other types of dispersion chambers, with or without beads  24 , may be used. For example, dispersion chambers  22  having baffles, deflection surfaces, impellers, etc., may be substituted for the dispersion chamber  22  described above. Similarly, various mouthpiece designs and configurations may also be used. While the mouthpiece  16  and chamber tube  18  are shown in the drawings as perpendicular to the chamber tube  18 , parallel/flow-through designs or other positional relationships between them may be used. These features described immediately above are not essential elements of the invention. 
     The specific size, shape and arrangement of various of the features shown  FIGS. 1 and 2  is arbitrary. The appearance of these features is a matter of design preference from a large array of options. These features may be selected or changed to create any desired ornamental external appearance of the inhaler  10 . 
     Thus, a novel inhaler has been shown and described. Various changes and substitutions may of course be made, without departing from the spirit and scope of the invention. The invention, therefore, should not be limited, except to the following claims, and their equivalents.