Abstract:
A spacer used with aerosol inhalers designed to lower plume force to comfortable levels and to be compact in size in order to conveniently fit in a pocket or purse as part of a drug delivery/actuator system with the geometry and material of the spacer have been selected to provide easy attachment to inhalers, to minimize drug retention, and to provide efficient dose delivery.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a spacer for use with a breath coordinated inhaler having a connection member for the inhaler providing improved dispensing of medicament, as well as attachment, and stowage with a breath coordinated inhaler. The spacer comprises a longitudinal air chamber shaped to be held in hand and compact enough to be conveniently portable with a breath coordinated inhaler.  
           [0003]    2. Description of the Prior Art  
           [0004]    In the prior art, it is well known that pressurized metered dose inhalers (pMDIs) can be used to deliver aerosol drugs or other inhalants to a patient. Typically drug from pMDIs exit the spray jet orifice in the form of aerosolized particles at velocities in excess of 50 meters/second. When the aerosol particles reach the back of the throat, the velocity can be 20 meters/second or more.  
           [0005]    Conventional pMDIs by the very nature of their drug delivery mode can produce an inconsistency in dose and region of deposition in the lung. Problems can include: a chilling effect of the propellant which may cause patients to cease the necessary inhalation maneuver prior to completion; a high velocity of aerosol which tends to encourage rapid inhalation restricting drug distribution in the lung; and the impact upon the throat of high velocity aerosol frequently causing gagging which can alter or halt the inhalation process.  
           [0006]    To minimize these problems and to deliver the drug in a more respirable form, spacers exist that are of numerous physical shapes and designs. Some are as simple and straightforward as extension tubes placing the mouth at a greater distance from the spray. Others decelerate the aerosol by means of tortuous flow path routes or bluff body impact areas. While effective in minimizing the problems of dose delivery by conventional pMDIs, the designs used for existing spacers can contribute to the loss of drug within the spacers.  
           [0007]    Another spacer category used to minimize the problems of conventional pMDIs are expansion chambers into which pMDIs are discharged. Medication is presented as a cloud having little or no exit impact force. An advantage is that the patient inhales the cloud created by aerosolizing a solution or suspension or dry powder with no need for concern regarding a synchronized pMDI discharge and inhalation maneuver. Problems arise with dose variability associated with retained drug. The time interval between presenting the aerosol to the chamber and inhalation may be such to cause “Rain Out”, i.e. the settling of drug onto the walls of the chamber. “Rain Out” can contribute to the loss of drug.  
           [0008]    Also, material selection can cause drug loss. Since spacers must be manufactured from bio-compatible and drug compatible materials, these materials can carry an electrostatic charge. Materials which carry static charge can significantly increase drug retention in actuators and spacers.  
           [0009]    As a result of the different design and material types of spacers as well as designs of attachment to inhalers; deposition and retention of the delivered dose of drug can be inconsistent. Because of this inconsistency, all of these devices retain drug, several over 50% requiring dispensing of larger doses to ensure adequate delivery. Since many of the drugs administered by inhalants are very expensive, more efficient delivery is an economic imperative.  
           [0010]    Also, with few exceptions all spacers are relatively large. That is, they are not conveniently portable with the inhaler in a pocket or a purse. Those few which are smaller and part of the inhaler actuator are among those retaining the most drug; therefore, more efficient delivery in a compact spacer can be practical as well as economic in use.  
           [0011]    Examples of prior art in this field include U.S. Pat. No. 4,534,343 entitled “Metered Dose Inhaler” issued to Nowacki et al. on Aug. 13, 1986; U.S. Pat. No. 4,674,491 entitled “Inhaler” issued to Brugger et al. on Jun. 23, 1987; U.S. Pat. No. 4,796,614 entitled “Collapsible Inhalation Valve” issued to Nowacki et al. on Jan. 10, 1989; U.S. Pat. No. 4,852,561 entitled “Inhalation Device” issued to Sperry on Aug. 01, 1989; U.S. Pat. No. 4,926,852 entitled “Medication Delivery System Phase One” issued to Zoltan et al on May 22, 1990; U.S. Pat. No. 5,012,803 entitled “Modular Medication Inhaler” issued to Foley et al. on May 7, 1991; U.S. Pat. No. 5,012,804 entitled “Medication Inhaler With Adult Mask” issued to Foley et al. on May 7, 1991; U.S. Pat. No. 5,505,194 entitled “Elliptical Cylinder Portions” issued to Adjei et al. on Apr. 19, 1996; and U.S. Pat. No. 5,904,139 entitled “Breath Coordinated Inhaler” issued to Hauser on May 18, 1999.  
         SUMMARY OF THE INVENTION  
         [0012]    It is therefore a further object of the invention to provide a spacer small enough to be incorporated as part of an inhaler actuator.  
           [0013]    It is therefore an object of the invention to provide a spacer in which drug delivery is optimized with the use of a breath coordinated inhaler.  
           [0014]    It is therefore a still further object of the invention to provide a spacer small enough to be used as an attachable accessory.  
           [0015]    It is therefore a still further object of the invention to provide a spacer in which drug retention is minimized.  
           [0016]    It is therefore a further object of the invention to provide a spacer which inhibits the velocity of inhalant to the user.  
           [0017]    It is therefore a still further object of the invention to provide a spacer with a minimized impact of inhalant delivery to the user.  
           [0018]    To attain the objects described the spacer will be molded to have attachment points which will be easily accommodated with the spacer docking piece of the breath coordinated inhaler sometimes referred to herein as “(BCI)” of U.S. Pat. No. 5,904,139, the disclosure of which is incorporated herein by reference. When used with the BCI, the spacer has the advantages of an expansion chamber without the level of drug loss. Uniformity of dose delivery can be better assured as a result of discharge synchronization, with a controlled inspiration rate and delivery of a soft plume via the spacer.  
           [0019]    The spacer will be molded with a generally rectangular cross section with slightly curved walls. The ratio of wall height to width of the cross section is at a ratio which optimizes decelerating pMDI discharge. As a result, drug exiting the spacer has a low impact plume force of 1-5 mN and a velocity of less than 1 meter per second. Another advantage of this design is that drug retention is reduced. Combined with the spacer sealing efficiently with a breath coordinated inhaler, both the attributes of drug availability and dose uniformity will be enhanced.  
           [0020]    Also, based upon the ratio of wall height to cross section, the spacer can be made small enough to be incorporated as part of an inhaler actuator or to be used as an attachable accessory.  
           [0021]    Also, the spacer made of material that has a slight electrical conductivity (1 Megohm or less/cm). This slight electrical conductivity inhibits electrostatic surface effects that would otherwise attract and retain drug. This inhibition can also lead to greater drug availability and dose uniformity.  
           [0022]    These and other objects and characteristics of the present invention will become apparent from the further disclosure to be made in the detailed description given below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]    The preferred embodiments of the present invention will now be explained in detail with reference to the accompanying drawings, wherein:  
         [0024]    [0024]FIGS. 1A and 1B are isometric views of the spacer of the present invention.  
         [0025]    [0025]FIG. 2 is a cross-sectional view of the spacer of the present invention illustrating a flow pattern when a pressurized multidose inhaler (pMDI) is discharged into the spacer.  
         [0026]    [0026]FIG. 3 is an exploded assembly view of the spacer of the present invention and the breath coordinated inhaler of U.S. Pat. No. 5,904,139.  
         [0027]    [0027]FIG. 4 depicts the spacer of the present invention and breath coordinated inhaler in dose delivery mode.  
         [0028]    [0028]FIG. 5 depicts the attachment and detachment of the spacer of the present invention from the breath coordinated inhaler.  
         [0029]    [0029]FIG. 6 depicts the storage of the spacer of the present invention on the breath coordinated inhaler. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0030]    Referring now to the drawings in detail wherein like numerals refer to like elements throughout the several views.  
         [0031]    [0031]FIGS. 1A and 1B depict a molded spacer  10  made, preferably, of polypropylene, however, any other material suitable for purpose may be used. The polypropylene preferably includes additives of anti-static material. This anti-static material will be sufficiently electrically conductive (Resistivity of 1 Megohm or less/cm) to inhibit retained surface charge thereby reducing deposition of the drug in the spacer. This anti-static material is currently available as Stat Kon. Stat Kon may be obtained from LNP Engineering Plastics, Inc. 475 Creamery Way, Exton, Pa. 19341; (610) 363-4500.  
         [0032]    The body  12  of the spacer  10  is an elongated hollow housing. The body  12 , exclusive of the inhaler adapter  14 , is somewhat rectangular defined by lower and upper cross-sectional walls  15  which are supported by slightly curved (outwardly bowed) side-walls  16 . The ratio of the height of each side-wall  16  to the width of each cross-sectional wall  15  is 0.78 or approximately 3 to 4. In general, the cross-sectional width to height ratio of between 1 (a circle) and 0.70 have been found to be efficient in decelerating pMDI aerosol discharge with the least drug retention. The pMDI aerosol discharge can be efficiently decelerated to a velocity of less than 1 meter/second.  
         [0033]    The length of the body  12  is, preferably, a minimum of two times the width of a cross-sectional wall  15 . The length of the body  12  combined with the contoured geometries of the cross-sectional wall  15  and side-walls  16  enhances aerosol expansion in a decelerated turbulent flow pattern as shown in FIG. 2.  
         [0034]    [0034]FIG. 2 illustrates a flow pattern within the spacer body  12  when a pressurized multi-dose inhaler (pMDI)  18  is discharged as the patient inhales through the mouthpiece  20 . The inhaler  18  is first shaken. The spacer body  12  is rotated down 90 degrees to the use position, slid back to engage the pMDI actuator body  22  and the mouthpiece  20  is inserted into patient&#39;s mouth. Upon depressing the pMDI canister  24 , drug is discharged via stem block  26  into spacer body  12 .  
         [0035]    Drug discharged  28  at high velocity enters spacer body  12  where it, along with patient&#39;s inhalation, cause ambient air  30  to enter from the inlet end  32  of the inhaler adapter  14 . This ambient air  30  becomes entrained along the interior  34  of the spacer body  12  providing a boundary layer  36  throughout transit of the spacer. This boundary layer  36  compresses the flow pattern within the spacer body  12  and limits the deposition and retention of drugs within the spacer body  12 . Propellant evaporation and turbulent flow with concomitant deceleration  38  occur as the drug discharged  28  moves toward the mouthpiece  20  to provide a plume  40 . There is some minimal exit velocity and a low impact force of 7 mN in the plume  40 . Minimal exit velocity is advantageous in decreasing “Rain Out” within the spacer. The low force of the plume  40  decreases impact on the user to a point similar to inhaling a suspended cloud of drug.  
         [0036]    [0036]FIGS. 1A and 1B detail the shape of the spacer  10 . In the spacer  10 , the distal end  42  of the body  12  is defined by the ends of cross-sectional walls  15  and side-walls  16 . The distal end  42  serves to receive a mouthpiece  20 . The mouthpiece  20  is provided with a flared end  44  sized to fit inside the distal end  42  of the body  12 . The mouthpiece  20  is hollow from end to end. The mouthpiece  20  tapers from the flared end  44  to an outlet end  46  with a smaller cross-sectional area. The outlet end  46  of the mouthpiece  20  has an elliptical diameter to accommodate the mouth of the patient.  
         [0037]    Covering the mouthpiece  20  when the inhaler is not in use is a mouthpiece cap  48 . The mouthpiece cap  48  is a hollowed contoured piece. The mouthpiece cap  48  is provided with a flared end  50  sized to cover the proximal end  52  of the mouthpiece  20  exterior of the distal end  42  of the body  12 . The mouthpiece cover  48  tapers from the flared end  50  to a solid end  54 , maintaining a slightly larger hollowed area than the exterior of the mouthpiece  20 . This provides for a conforming fit over the mouthpiece  20 . The solid end  54  has a smaller cross-sectional area than the flared end  50  and has an elliptical diameter to cover the outlet end  46  of the mouthpiece  20 .  
         [0038]    On the opposite end  56  of the spacer  10 , the body  12  reduces in cross-sectional area by tapering to accommodate the inhaler adapter  14 , an integral part of the body  12 . The inhaler adapter  14  is a longitudinally shaped chamber formed to receive a commercially available canister of medication under pressure ( 18  of FIG. 2) or a breath coordinated inhaler ( 76  of FIG. 3). In FIG. 1B, the inhaler adapter  14  is somewhat rectangular with a hollowed out center defined by lower and upper cross-sectional walls  58  which are supported by slightly curved (outwardly bowed) side-walls  60  and  62 .  
         [0039]    Side-walls  60 ,  62  have an axial protrusion  64  tapering outward from the inhaler adapter  14 . The axial protrusion  64  on side-wall  60  is not depicted in FIGS. 1A and 1B but is directly opposite the axial protrusion  64  on sidewall  62 . Recesses are located in the upper section  66  and the lower section  68  of the axial protrusion  64  to be attachment points for connection to a breath coordinated inhaler or pMDIs.  
         [0040]    The inlet end wall  70  of the inhaler adapter  14  has a circular aperture  71  to accommodate a breath coordinated inhaler as well as conventional inhalers. The outlet end of the inhaler adapter  14  is integral with and boundaried by the tapered end  72  of the truncated cross-sectional area  74 .  
         [0041]    [0041]FIG. 3 depicts an exploded assembly view of the mouthpiece cover  48 , mouthpiece  20 , spacer  10 , and breath coordinated inhaler  76 . The breath coordinated inhaler depicted is that is shown in U.S. Pat. No. 5,904,139 issued to Hauser. BCI  76  consists of a spacer docking piece  78  detachable from the breath coordinated inhaler  76 , to allow for cleaning. The spacer docking piece  78  is a three wall body where the two vertical walls  80 ,  82  are connected by concave bridge  84 . Protruding from the interior of walls  80 ,  82  are two pivot pins  84 ,  86 . Pivot pins  84 ,  86  are angled at 135 degrees relative to the bottom  88  of the spacer docking piece  88 . The angling of pivot pins  84 ,  86  assists in the attachment and detachment of spacer  10 .  
         [0042]    The bottom  88  of the spacer docking piece  78  curves upward to provide a lip  90 . The lip  90  provides additional sealing when the spacer  10  is in the stowed position as shown in FIG. 6. In FIG. 3, the distal end  92  of the spacer docking piece  78  has vertical protrusions  94 ,  96  along the exterior of walls  80 ,  82 . These vertical protrusions  94 ,  96  are used as securing points with the BCI  76 . Protrusions  94 ,  96  slide into notches  98 ,  100  which are integral to the lower housing member  102  of the BCI  76 .  
         [0043]    At the bottom of the lower housing member  102  is an aperture  104 . Aperture  104  mirrors the perimeter of the aperture  71  of inlet end wall  70  of the inhaler adapter  14 . The close fit of apertures  71  and  104  allows an enhanced seal between the spacer  10  and BCI  76 , when the canister  18  is discharged.  
         [0044]    Lower housing member  102  is a casing sized to accommodate the dimensional variations of canister  18 . The upper housing member  106  slidably fits into the matingly shaped lower housing member  102  and the plunger  108 . The upper housing member  106  is a casing sized to accommodate the upper dimensional variations of canister  18  while transmitting pressure applied to the plunger  108  to the cylinder  18 . The plunger  108  is a cap in which the interior is sized to accommodate the upper housing member  106  and which the exterior is shaped to accommodate the user.  
         [0045]    When the spacer  10  is used in conjunction with the breath coordinated inhaler  76 , the spacer  10  has the advantages of an expansion chamber without the level of drug loss. In FIG. 4, the spacer  10  and breath coordinated inhaler  76  are attached for dose delivery. The BCI  76  is first shaken. The spacer  10  is set perpendicular to the BCI  76  and is slid back in the direction of arrow  109  in a bayonet fashion to engage the lower housing member  102  of the BCI  76  at the axial protrusion  64  of sidewalls  60 ,  62  of the inhaler adapter  14 . This forms a seal between the spacer  10  and aperture  104  which, in the case of the use of the BCI type device, is important. The mouthpiece  20  is inserted into the user&#39;s mouth.  
         [0046]    Upon applying pressure  110  to the plunger  108 , pressure  110  is transmitted by way of the upper housing member  106  to the cylinder  18  within the BCI  76 . Drug is discharged through the aperture  104  of the lower housing member  102  to the aperture  71  of inhaler adapter  14  and into spacer  10 . Ambient air  112  enters through spacing between the upper housing member  106  and the plunger  108 . Ambient air  112  provides a boundary layer within the spacer  10  assisting in the delivery of the discharged drug. Drug discharged exits the mouthpiece  20  as a plume  40  which the user inhales. Uniformity of dose delivery is better assured as a result of BCI  76  discharge synchronization, with the result being a controlled inspiration rate and delivery of a soft plume  40  of medication via the spacer  10 .  
         [0047]    [0047]FIG. 5 depicts the attachment and detachment of the spacer  10  from the breath coordinated inhaler  76 . The spacer  10  would normally be detached from the BCI  76  for cleaning purposes. A spacer docking piece  78  of the BCI  76  is the mounting point for the spacer  10 . The axial protrusion  64  of sidewalls  60 ,  62  of the inhaler adapter  14  aligns at 45 degrees relative to the BCI  76  and then locks onto the extruding pivot points  84 ,  86  of the spacer docking piece  78 . This process allows easy attachment of the spacer  10  to the BCI  76 . The spacer  10  can also detach from the pivot points  84 ,  86  by sliding out at a 45 degree angle relative to the BCI  76  for cleaning or other purpose.  
         [0048]    [0048]FIG. 6 shows that the spacer  10  can be rotated ninety degrees upward from its discharge position (shown in FIG. 4) to be stowed within a recessed area  114  of the breath coordinated inhaler  76 . The spacer  10  rotates on pivot points  84 ,  86  to a vertical position with the inhaler adapter  14  resting within the spacer docking piece  76  with a protrusion or nub  116  providing a bearing surface releasibly locking it in place.  
         [0049]    While the invention has been described in connection with what is considered to be the most practical and preferred embodiment, it should be understood that this invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.