Abstract:
The inhaler for aerosol medication is an inhaler having a recirculation chamber or rebreather. The inhaler has an aerosol holding chamber having an inlet end for attaching a holder for aerosol medication or nebulizer device thereto and an outlet end for attachment to a mouthpiece or mask for dispensing the medication or substance to the user, with a recirculation chamber depending from the outlet end of the holding chamber or from a mask extending from the outlet end of the chamber. The recirculation chamber has a filter to capture particles of the dispensed substance and prevent their escape from the device to the ambient air. The recirculation chamber may be folded or collapsed for storage within the volume of the aerosol holding chamber. The aerosol holding chamber may be stored within the recirculation chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/924,681, filed May 25, 2007. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to devices for dispensing medication and related substances. More particularly, the present invention relates to an inhaler for aerosol medication. 
   2. Description of the Related Art 
   Inhalers for dispensing aerosol medication and related substances have been known for quite some time. These devices are commonly used to dispense medication in aerosol form for asthma attacks and other respiratory and medical conditions. Such devices include metered dose inhalers (MDI) and nebulizers. The MDI includes a canister and a sleeve. The canister releases a measured dose of medication when squeezed that is released as a puff of medication through the sleeve. Nebulizers generally are machines that use an air compressor or the like to convert liquid medication into a fine mist. Nebulizers generally require the use of a power supply, although lightweight, handheld nebulizers that operate on battery power are available. Nebulizers often use a face mask for delivery of the medication. 
   A problem with such devices is that they are not particularly efficient. Generally, a person suffering from an asthma attack is incapable of taking a deep breath, so much of the medication does not reach the lungs where it is needed, at least in the first few breaths. Consequently, the unabsorbed medication is retained in the mouth and the throat, or may merely be exhaled into the ambient air. For this reason, metered dose inhalers are often used with a spacer (a tube or other reservoir) disposed between the sleeve and the patient&#39;s mouth to hold the metered dose of medication until the patient is able to breathe deeply enough to inhale more of the medication into the lungs. Nevertheless, a substantial quantity of the medication does not reach the lungs, and may be exhaled, either mediately after a retention period in the mouth and throat, or immediately. 
   Such medications (e.g., corticosteroids, long term or short term beta-agonists (bronchodilators), and other medications used in aerosol form to treat certain medical conditions) can be harmful to the eyes. Yet with such relatively simple inhalers, the user, caregivers, and others in the immediate vicinity of the patient are subjected to the aerosolized medication, at least upon exhalation. 
   German Patent No. 19,700,838, published on Jul. 16, 1998, describes (according to the drawings and English abstract) a tube that connects to an aerosol inhaler, together with a collapsible, flexible bag or pouch extending from the opposite end of the tube. The bag or pouch includes a mouthpiece at the end distal from the tube, with the interior volume of the pouch communicating with that of the tube to allow the nebulized or vaporized substance to flow from the inhaler through the tube and pouch and into the mouth of the user. The pouch is formed of a flexible material and may be collapsed and stored within the tube for compact storage. 
   Thus, an inhaler for aerosol medication solving the aforementioned problems is desired. 
   SUMMARY OF THE INVENTION 
   The inhaler for aerosol medication is an inhaler that includes a recirculation chamber or rebreather. The inhaler includes an aerosol holding chamber having an inlet end for the attachment of a holder of aerosol medication or nebulizer device thereto. The opposite outlet end of the holding chamber attaches to a mouthpiece or mask for dispensing the medication or substance to the user. 
   The inhaler includes a recirculation chamber depending from the outlet end of the aerosol holding chamber, or from a mask extending from the outlet end of the aerosol holding chamber. The recirculation chamber has a filter at its distal end to capture particles of the dispensed medication or other substance and prevent their escape from the device to the ambient air. 
   Different valve arrangements may be incorporated in different embodiments of the inhaler to allow or prevent recirculation into and from the aerosol holding chamber and to provide different pathways for the flow. In at least one embodiment, the recirculation chamber may be folded or collapsed for storage within the volume of the aerosol holding chamber. In at least one other embodiment, the aerosol holding chamber may be stored within the recirculation chamber for compact storage. 
   These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a first embodiment of an inhaler for aerosol medication according to the present invention. 
       FIG. 1A  is a perspective view of a modification of the inhaler of  FIG. 1 , wherein a flexible rebreather bag is substituted for the rigid rebreather chamber of  FIG. 1 . 
       FIG. 2  is a right side elevation view in section of the inhaler of  FIG. 1 , showing various internal details thereof and the flow path therethrough. 
       FIG. 3  is a perspective view of a second embodiment of an inhaler for aerosol medication according to the present invention, wherein the device includes a face mask. 
       FIG. 3A  is a perspective view of a modification of the inhaler of  FIG. 3 , wherein a flexible rebreather bag is substituted for the rigid rebreather chamber of  FIG. 3 . 
       FIG. 4  is a right side elevation view in section of the inhaler of  FIG. 3 , showing various internal details thereof and the flow path therethrough. 
       FIG. 5  is a perspective view of a third embodiment of the inhaler for aerosol medication according to the present invention, wherein the recirculation chamber comprises a collapsible bellows for compact storage. 
       FIG. 6  is a perspective view of the inhaler of  FIG. 5 , showing the recirculation bellows in a collapsed configuration. 
       FIG. 7  is a perspective view of the inhaler of  FIGS. 5 and 6 , showing the device completely folded and closed for storage. 
       FIG. 8  is a right side elevation view in section of the inhaler of  FIG. 5  in operation, showing various internal details thereof and the flow path therethrough. 
       FIG. 9  is a perspective view of a fourth embodiment of an inhaler for aerosol medication according to the present invention, wherein the holding chamber may be stored within the recirculation chamber. 
       FIG. 10  is an exploded perspective view of the inhaler of  FIG. 9 , showing the opened end of the recirculation chamber for insertion of the holding chamber therein. 
       FIG. 11  is an exploded perspective view of the inhaler of  FIGS. 9 and 10 , showing the closed recirculation chamber and the aerosol medication holder separated therefrom. 
       FIG. 12  is a right side elevation view in section of the inhaler of  FIG. 9  in operation, showing various internal details thereof and the flow path therethrough. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is an inhaler for aerosol medication having a recirculation chamber with a filtered outlet to preclude or greatly diminish the escape of medication to the ambient air.  FIGS. 1 and 2 , respectively, provide a perspective view and a right side elevation view in section of a first embodiment of the inhaler  110 , in which the inhaler  110  has a rigid recirculation chamber immovably affixed thereto. The inhaler  110  includes a hollow aerosol holding chamber  112  having a medication dispenser attachment end  114  and a delivery end  116  opposite the dispenser attachment end  114 . The dispenser attachment end  114  may accept a conventional metered dose inhaler (MDI) with its manually operated medication container or canister C, or, alternatively, a nebulizer N may be attached to the medication dispenser attachment end  114  of the aerosol holding chamber  112 , as shown in  FIG. 1 . The aerosol holding chamber  112  may have an octagonal cross section, as shown, or may have any other regular or irregular geometric cross-sectional shape, as desired. 
   An intermediate tube  118  extends from the delivery end  116  of the chamber  112 , with the intermediate tube having a first end  120  attached to the delivery end  116  of the chamber  112  and an opposite user interface device attachment end  122  extending therefrom. A user interface device, e.g., a mouthpiece  124 , as shown in  FIGS. 1 and 2 , may be removably or permanently affixed to the user interface device attachment end  122  of the intermediate tube  118 . 
   A recirculation chamber  126  has a rigid shell  128  with an attachment end  130  connected to, and communicating with, the intermediate tube  118 , and an opposite, distal end  132 . The recirculation chamber  126  may have any practicable geometric cross-sectional shape or configuration, as desired. An additional recirculation feedback passage  134  extends from the attachment end  130  of the recirculation chamber  126  to the aerosol holding chamber  112 , with the recirculation passage  134  communicating with the intermediate tube  118  of the embodiment  110  of  FIGS. 1 and 2  by means of the connection of both the delivery end  116  of the aerosol holding chamber  112  and the attachment end  130  of the recirculation chamber  126  to the intermediate tube  118 . 
   The inhaler  110  of  FIGS. 1 and 2  has a plurality of one-way check valves therein in order to control the flow of air and/or medication through the device. The side elevation view in section of  FIG. 2  illustrates the flow paths through the device, and the locations of the various check valves therein. The check valves may be of any suitable configuration, e.g., spring loaded ball check valves, spring loaded poppet valves, etc., but preferably comprise what are commonly known as membrane or “reed” type valves, i.e., a thin, flexible sheet of material secured to one side of an open frame, with the sheet freely flexing away from the frame as air (or other fluid) flows through the frame to push the sheet away from the frame, but sealing against fluid flow in the opposite direction as the flexible sheet is pushed against the frame by differential pressure. This type of valve, when incorporating a very thin, flexible sheet of rubber, vinyl, or similar material, is quite economical, reasonably durable, and operates very rapidly using very little differential air or fluid pressure. 
   Air is initially drawn into the aerosol holding chamber  112  through a pair of inlet check valves  136  installed in the side or top of the aerosol holding chamber  112  simultaneously with the injection of medication into the chamber  112  by means of the MDI or nebulizer N. The aerosol holding chamber inlet check valves  136  are oriented to permit air to flow into the aerosol holding chamber  112 , while blocking outflow. Thus, in the event that pressure within the aerosol holding chamber  112  becomes higher than ambient, air (and medication) cannot escape through the inlet check valves  136 . While two such inlet check valves  136  are illustrated in  FIGS. 1 and 2 , it should be noted that a single such valve, or more than two such valves, may be incorporated into the aerosol holding chamber  112 . 
   Air and medication mixed therewith passes from the aerosol holding chamber  112  to the intermediate tube  118  and thence to the user interface device  124  (or other device) through an intermediate one-way check valve  138  installed at the outlet or delivery end  116  of the aerosol holding chamber  112 . This intermediate valve  138  permits fluid flow from the holding chamber  112  into the intermediate tube  118 , and thence into the mouthpiece  124  (or other device), while blocking flow in the reverse direction from the mouthpiece  124  back into the holding chamber  112 . 
   Any air (and medication) exhaled by the user back into the mouthpiece  124  passes into the recirculation chamber  126  by way of the attachment end passage  130  thereof, which connects the recirculation chamber  126  to the intermediate tube  118 . A recirculation check valve  140  is provided at the outlet end of the recirculation passage  134 , where the recirculation passage  134  connects to the aerosol holding chamber  112 , in order to permit exhaled air and medication to flow back into the aerosol holding chamber  112  for recycling while preventing flow from the holding chamber  112  directly into the recirculation chamber  126  through the recirculation passage  134 . Alternatively, the recirculation check valve  140  may be installed in the attachment end  130  of the recirculation chamber  126 , i.e., the inlet side or passage of the recirculation chamber  126 . Such an alternative recirculation valve location is indicated as valve  140   a  in  FIG. 2 . Alternatively, the attachment end  130  of the recirculation chamber  126  may include two (or more) passages extending therefrom, with each passage including a separate one-way recirculation check valve  140   a . It will be understood that it is not necessary to provide both recirculation valves  140  and  140   a , as the inlet and outlet passages  130  and  134  of the recirculation chamber  126  comprise a plurality flow, so only a single recirculation valve  140  or  140   a  is required at some point in the inlet or outlet side of the recirculation chamber  126 . 
   The above-described system is a one-way system, i.e., no outflow is permitted through any of the passages other than the mouthpiece  124  (or other user interface device). Accordingly, some means must be provided to vent the device in order to allow the user to exhale back into the device in order to recirculate air and medication for efficient reuse. This is provided by an outflow check valve  142  located in the distal end  132  of the recirculation chamber  126 , along with an exhalation filter  144 . The exhalation filter  144  is preferably an HME (Heat and Moisture Exchanger) type filter, i.e., activated charcoal capable of capturing medication in suspended vapor form, viruses, etc., or a HEPA (High Efficiency Particulate Air) filter with much the same capabilities. In any event, the exhalation filter  144  should be capable of preventing the escape of vaporized or nebulized medication from the recirculation chamber  126 . 
     FIG. 1A  is a perspective view of an alternative inhaler for aerosol medication  110   a , based upon the inhaler embodiment  110  of  FIG. 1 . The aerosol holding chamber  112  with its provision for the attachment of a nebulizer N or MDI, mouthpiece  124 , and various check valves, are identical in both the inhaler  110  of  FIGS. 1 and 2  and the inhaler  110   a  of  FIG. 1A . However, the inhaler  110   a  of  FIG. 1A  includes a flexible recirculation bag  126   a , rather than the rigid recirculation chamber  126  of the inhaler  110 . The flexible recirculation bag  126   a  includes an outflow check valve and exhalation filter in its distal end  132 , which are substantially identical to the outflow check valve  142  and filter  144  of the rigid recirculation chamber  110  of  FIGS. 1 and 2 . The flexible recirculation bag  126   a  of the embodiment  110   a  of  FIG. 1A  provides advantages in the compact storage of the inhaler  110   a , as the flexible bag  126   a  may be collapsed for storage of the device. 
     FIGS. 3 and 4  respectively show a perspective view and a right side elevation view in section of a second embodiment of an inhaler for aerosol medication, designated as  210  in the drawings. The inhaler  210  includes many of the same basic components as the inhaler  110  of  FIGS. 1 and 2 , with equivalent components having three digit reference numerals with the same second and third digits as those used for the equivalent components of the inhaler  110 . The inhaler  210  includes an aerosol holding chamber  212  having a medication dispenser attachment end  214  and a delivery end  216  opposite the dispenser attachment end. The dispenser attachment end  214  may accept a conventional metered dose inhaler (MDI) with its manually operated medication container or canister C, or alternatively a nebulizer N may be attached to the medication dispenser attachment end  214  of the aerosol holding chamber  212 , as shown with the inhaler embodiment  110  of  FIG. 1 . The aerosol holding chamber  212  may have a round cross section, or any other practicable cross-sectional shape. 
   An intermediate tube  218  extends from the delivery end  216  of the chamber  212 , with the intermediate tube having a first end  220  attached to the delivery end  216  of the chamber  212  and an opposite user interface device attachment end  222  extending therefrom. A user interface device, e.g., a face mask  224  as shown in  FIGS. 3 and 4 , may be removably or permanently affixed to the user interface device attachment end  222  of the intermediate tube  218 . The use of a face mask  224 , rather than a mouthpiece, as the user interface device is the primary difference between the inhaler  110  of  FIGS. 1 and 2  and inhaler  210  of  FIGS. 3 and 4 . However, there are other differences in the arrangement of similar components, and the possible omission or addition of various valves. 
   Recirculation chamber  226  has a rigid shell  228  with an attachment end  230  connected to and communicating with the face mask  224 , and an opposite, distal end  232 . The recirculation chamber  226  may have any practicable geometric cross-sectional shape or configuration. An additional recirculation passage  234  extends from the attachment end  230  of the recirculation chamber  226  to an inlet in the face mask  224 , with the recirculation passage  234  communicating with the intermediate tube  218  of the embodiment  210  of  FIGS. 3 and 4  by means of the connection of both the attachment end  230  of the recirculation chamber  226  (with the recirculation passage  234  extending therefrom) to the face mask  224  and the attachment of the intermediate tube  218  to the face mask  224 . 
   The inhaler  210  of  FIGS. 3 and 4  further includes a plurality of one-way check valves therein in order to control the flow of air and/or medication through the device. The side elevation view in section of  FIG. 4  illustrates the flow paths through the device, and the locations of the various check valves therein. The check valves may be of any suitable configuration, as described further above in the description of the check valves for the embodiment  110  of  FIGS. 1 and 2 . 
   It will be noted that the inhaler  210  of  FIGS. 3 and 4  does not include any air inlet valves in the aerosol holding chamber  212 , unlike the chamber  112  of the embodiment of  FIGS. 1 and 2 . Rather, inhalation through the mask  224  draws ambient air in through a one-way inlet check valve  236  disposed within the face mask  224 . This check valve  236  is located laterally, symmetrically from the mask connection for the recirculation passage  234 , but the edge of the valve  236  may be seen in  FIG. 3 . The face mask inlet check valve  236  is oriented to permit air to flow into the face mask  224  while blocking outflow. Alternatively, two or more such inlet check valves  236  could be installed in the mask  224  to reduce restriction in the inflow of air to the mask. Such multiple inlet check valves are indicated as valves  136  in the inhaler  110  embodiment of  FIGS. 1 and 2 , valves  336  in the inhaler embodiment  310  of  FIGS. 5 through 8 , and valves  436  in the inhaler embodiment  410  of  FIGS. 9 through 12 . 
   Some means must be provided for mixing ambient air with the medication delivered to the aerosol holding chamber  212  by the MDI or nebulizer N, in view of the fact that the inhaler embodiment  210  does not include any inlet valves communicating directly with the interior of the holding chamber  212 . Accordingly, the inhaler embodiment  212  does not include any form of intermediate check valve between the holding chamber  112  and the intermediate passage  218  to the mask  224 . Thus, the user may draw in ambient air through the mask inlet check valve  236  and exhale freely back through the intermediate tube  218  into the aerosol holding chamber  212  to mix the vaporized medication from the MDI or nebulizer N with exhaled air. Alternatively, an inlet check valve(s) could be provided in the aerosol holding chamber  212  and the inlet check valve of the face mask  224  could be eliminated, if an intermediate check valve were to be installed within the intermediate tube of the embodiment  210  of  FIGS. 3 and 4 . 
   Any air (and medication) exhaled by the user back into the face mask  224  passes either into the aerosol holding chamber  212  as described above, or into the recirculation chamber  226  by way of the attachment end passage  230  thereof connecting the recirculation chamber to the face mask  224 . A recirculation check valve  240  may be provided at the outlet end of the recirculation passage  234  where the recirculation passage  234  connects to the face mask  224  to permit exhaled air and medication to flow back into the aerosol holding chamber  212  for recycling while preventing backflow through the recirculation passage  234 . It will be understood that the recirculation valve  240  is not absolutely necessary in the configuration illustrated in  FIG. 4 , with its lack of a check valve between the face mask  224  and the aerosol holding chamber  212 . The recirculation check valve  240  may only be required when one or more inlet valves are provided in the aerosol holding chamber  212 , rather than in the face mask  224 , and an intermediate check valve is installed between the holding chamber  212  and the face mask  224 . Another recirculation check valve  140   a  may be installed in the attachment end  230  of the recirculation chamber  226 , i.e., the inlet side or passage of the recirculation chamber  226  where it joins to the face mask  224 . The installation of the two recirculation check valves  140  and  140   a  ensures that flow will pass into the recirculation chamber  226  through the attachment end  230  thereof and exit through the recirculation passage  234 , as indicated by the flow arrows in  FIG. 4 . 
   The above-described system is a one-way system, i.e., no outflow is permitted through any of the passages other than the face mask  224  (or other user interface device). Accordingly, some means must be provided to vent the device in order to allow the user to exhale back into the device in order to recirculate air and medication for efficient reuse. This is provided by an outflow check valve  242  located in the distal end  232  of the recirculation chamber  226 , along with an exhalation filter  244  of the general type and properties described further above for the exhalation filter  144  of the inhaler embodiment  110  of  FIGS. 1 and 2 . 
     FIG. 3A  is a perspective view of an alternative inhaler for aerosol medication  210   a , based upon the inhaler embodiment  210  of  FIGS. 3 and 4 . The aerosol holding chamber  212  with its provision for the attachment of a nebulizer N or MDI, face mask  224 , and various check valves, are identical in both the inhaler  210  of  FIGS. 3 and 4  and the inhaler  210   a  of  FIG. 3A . However, the inhaler  210   a  of  FIG. 3A  includes a flexible recirculation bag  226   a  substantially identical to the flexible recirculation bag  126   a  of  FIG. 1A , rather than the rigid recirculation chamber  226  of the inhaler  210 . The flexible recirculation bag  226   a  includes an outflow check valve and exhalation filter in its distal end  232 , which are substantially identical to the outflow check valve  142  and filter  144  of the rigid recirculation chamber embodiment  110  of  FIGS. 1 and 2 , and are also incorporated in the embodiment  210  of  FIGS. 3 and 4  as valve  242  and filter  244 . The flexible recirculation bag  226   a  of the inhaler  210   a  of  FIG. 3A  provides advantages in the compact storage of the inhaler  210   a , as the flexible bag  226   a  may be collapsed for storage of the device. 
     FIGS. 5 through 8  illustrate a third embodiment of the inhaler for aerosol medication, designated as inhaler  310 . The inhaler  310  includes many of the same basic components as the inhaler  110  of  FIGS. 1 and 2  and inhaler  210  of  FIGS. 3 and 4 , with equivalent components having three digit reference numerals with the same second and third digits as those used for the equivalent components of the inhalers  110  and  210 . The inhaler  310  includes a telescoping aerosol holding chamber  312  having an outer portion  312   a  with a medication dispenser attachment end  314 , an inner portion  312   b  with a delivery end  316  opposite the medication dispenser attachment end  314 , and a selectively closable cover  317  extending from the outer portion  312   a . The dispenser attachment end  314  may accept a conventional metered dose inhaler (MDI) with its manually operated medication container or canister C, or alternatively a nebulizer N may be attached to the medication dispenser attachment end  314  of the aerosol holding chamber  312 , as shown with the inhaler embodiment  110  of  FIG. 1 . The telescoping aerosol holding chamber  312  may have a rectangular cross section as shown, or any other practicable cross-sectional shape. 
   An intermediate tube  318  extends from the delivery end  316  of the chamber  312 , with the intermediate tube having a first end  320  attached to the delivery end  316  of the chamber  312  and an opposite user interface device attachment end  322  extending therefrom. A user interface device, e.g., a mouthpiece  124  as shown in  FIGS. 1 and 2  or a face mask  224  as shown in  FIGS. 3 and 4 , may be removably or permanently affixed to the user interface device attachment end  322  of the intermediate tube  318 . 
   A collapsible bellows recirculation chamber  326  has an attachment end  330  connected to and communicating with the intermediate tube  318 , and a distal end  332  opposite the attachment end. The recirculation chamber  326  may have any practicable geometric cross-sectional shape or configuration, with the cross-sectional shape being limited by the need to collapse the chamber  326  for compact storage. An additional recirculation passage  334 , shown in  FIGS. 6 and 8 , extends from the attachment end  330  of the recirculation chamber  326  to the inlet end  316  of the inner portion  312   b  of the aerosol holding chamber  312 , with the recirculation passage  334  communicating with the intermediate tube  318  of the inhaler  310  of  FIGS. 5 through 8  by means of the connection of the attachment end  330  of the recirculation chamber  326  (with the recirculation passage  334  extending therefrom) to the delivery end  316  of the inner portion  312   b  of the aerosol holding chamber  312  and the attachment of the chamber  312  to the intermediate tube  318 . 
   The inhaler  310  of  FIGS. 5 through 8  further includes a plurality of one-way check valves therein in order to control the flow of air and/or medication through the device. The side elevation view in section of  FIG. 8  illustrates the flow paths through the device and the locations of the various check valves therein. The check valves may be of any suitable configuration, as described further above in the description of the check valves for the embodiment  110  of  FIGS. 1 and 2 . 
   Air is initially drawn into the aerosol holding chamber  312  through a pair of inlet check valves  336  installed in the side or top of the aerosol holding chamber  312 , particularly in the top of the inner portion  321   b  thereof, simultaneously with the injection of medication into the chamber  312  by means of the MDI or nebulizer N. The aerosol holding chamber inlet check valves  336  are oriented to permit air to flow into the aerosol holding chamber  312  while blocking outflow. Thus, in the event that pressure within the aerosol holding chamber  312  becomes higher than ambient, air (and medication) cannot escape through the inlet check valves  336 . While two such inlet check valves  336  are illustrated in  FIGS. 5 and 8 , it should be noted that a single such valve, or more than two such valves, may be incorporated as desired. 
   Air and medication mixed therewith passes from the aerosol holding chamber  312  to the intermediate tube  318  and thence to the user interface device (e.g., the mouthpiece  124  of  FIGS. 1 and 2 , or the face mask  224  of  FIGS. 3 and 4 ) through an intermediate one-way check valve  338  installed at the outlet or delivery end  316  of the aerosol holding chamber  312 . This intermediate valve  338  permits fluid flow from the holding chamber  312  into the intermediate tube  318  and thence into the user interface device, while blocking flow in the reverse direction from the user interface device back into the holding chamber  312 . 
   Any air (and medication) that is exhaled by the user back through the user interface device passes into the recirculation chamber  326  by way of the attachment end passage(s)  330  thereof connecting the recirculation chamber to the intermediate tube  318 . A recirculation check valve  340  is provided within the recirculation passage  334  where the recirculation passage  334  connects to the aerosol holding chamber  312  (or more precisely, to its inner portion  312   b  adjacent the delivery end thereof) to permit exhaled air and medication to flow back into the aerosol holding chamber  312  for recycling while preventing flow from the holding chamber  312  directly into the recirculation chamber  326  through the recirculation passage  334 . Alternatively, the recirculation check valve may be installed in the attachment end passage(s)  330  of the recirculation chamber  326 , i.e., the inlet side or passage of the recirculation chamber  326 . Such an alternative recirculation valve location is indicated as valve  340   a  in  FIG. 8 . Alternatively, the attachment end  330  of the recirculation chamber  326  may include two (or more) passages extending therefrom, with each passage including a separate one-way recirculation check valve  340   a . It will be understood that it is not necessary to provide both recirculation valves  340  and  340   a , as the inlet and outlet passages  330  and  334  of the recirculation chamber  326  comprise a plurality flow, so that only a single recirculation valve  340  or  340   a  is required at some point in the inlet or outlet side of the recirculation chamber  326 . 
   The above-described system is a one-way system, i.e., no outflow is permitted through any of the passages other than the intermediate tube  318  and any user interface device connected thereto. Accordingly, some means must be provided to vent the device in order to allow the user to exhale back into the device in order to recirculate air and medication for efficient reuse. This is provided by an outflow check valve  342  located in the distal end  332  of the recirculation chamber  326 , along with an exhalation filter  344  of the general type and properties described further above for the exhalation filter  144  of the inhaler embodiment  110  of  FIGS. 1 and 2 . The distal end  132  and  232  of the embodiments  110  and  210 , with their respective exhalation check valves  142  and  242  and filters  144  and  244  have been shown respectively in  FIGS. 2 and 4  and discussed further above, and are indicated only generally in the cross-sectional side elevation view of  FIG. 8 . 
     FIGS. 5 through 7  also illustrate the general progression in converting the inhaler  310  from its deployed to its collapsed or stowed configuration for compact storage. The device  310  is shown fully deployed with the bellows recirculation chamber  326  fully extended in  FIG. 5  and ready for use, with perhaps the only additional component needed being the mouthpiece  124  of the embodiment of  FIGS. 1 and 2  or the face mask  224  of the embodiment of  FIGS. 3 and 4 . The inhaler  310  is collapsed for storage by first folding the collapsible bellows recirculation chamber  326 , as shown in  FIG. 6 . Normally, a cap or closure (not shown) would be placed over the otherwise exposed user interface connection end  322  of the intermediate tube  318  in order to assure that all vapor contained within the inhaler device  310  remains within the device. Any air and/or medication vapor contained within the expanded bellows chamber  326  is forced through the outflow check valve and exhalation filter assembly  342 ,  344  as the chamber  326  is collapsed, with any medication and/or other large molecule particulate matter being captured in the exhalation filter  344 . 
   When the bellows recirculation chamber  326  has been completely collapsed, as shown in  FIG. 6 , the inner portion or sleeve  312   b  of the aerosol holding chamber  312  is telescoped into the outer portion or sleeve  312   a  of the holding chamber. Air and/or vapor, etc., captured within the aerosol holding chamber  312  as it is collapsed is forced from the holding chamber  312  into the intermediate tube  318  through the intermediate check valve  338 , and thence into the collapsed bellows recirculation chamber  326  through the recirculation check valve  340   a  and out the outflow check valve and filter  342 ,  344 . Once this has been completed, the hinged cover or cap  317  is swung upwardly to cover the otherwise protruding intermediate tube  318  and its user interface connector end  322  to completely enclose the collapsed recirculation chamber  326 , intermediate tube  318 , and inner sleeve portion  312   b  of the aerosol holding chamber  312 , as shown in  FIG. 7 . The MDI or nebulizer N may be disconnected at this point, if so desired, and stored for future use. 
     FIGS. 9 through 12  illustrate a fourth embodiment of an inhaler for aerosol medication, designated as inhaler  410 . The inhaler  410  includes many of the same basic components as the inhaler  110  of  FIGS. 1 and 2 , inhaler  210  of  FIGS. 3 and 4 , and inhaler  310  of  FIGS. 5 through 8 , with equivalent components having three digit reference numerals with the same second and third digits as those used for the equivalent components of the inhalers  110 ,  210 , and  310 . The inhaler  410  includes a telescoping aerosol holding chamber  412  having an outer portion  412   a  with a medication dispenser attachment end  414 , and an inner portion  412   b  with a delivery end  416  opposite the medication dispenser attachment end  414 . The dispenser attachment end  414  may accept a conventional metered dose inhaler (MDI) with its manually operated medication container or canister C, or, alternatively, a nebulizer N may be attached to the medication dispenser attachment end  414  of the aerosol holding chamber  412 , as shown with the inhaler  110  of  FIG. 1 . The telescoping aerosol holding chamber  412  may have a rectangular cross section as shown, or any other practicable cross-sectional shape. 
   An intermediate tube  418  extends from the delivery end  416  of the chamber  412 , with the intermediate tube having a first end  420  attached to the delivery end  416  of the chamber  412  and an opposite user interface device attachment end  422  extending therefrom. A user interface device, e.g., a mouthpiece  124  as shown in  FIGS. 1 and 2  or a face mask  224  as shown in  FIGS. 3 and 4 , may be removably or permanently affixed to the user interface device attachment end  422  of the intermediate tube  418 . 
   A combination recirculation and aerosol holding chamber storage chamber  426  (hereinafter called the “combination chamber  426 ”) has a rigid shell  428  with an attachment end or attachment end passage(s)  430  removably connected and communicating with the intermediate tube  418 , a distal end  432  opposite the attachment end or attachment end passage(s)  430 , and a selectively openable cover  431  disposed upon the attachment end and secured thereto by hinges  433 . The combination chamber  426  may have any practicable geometric cross-sectional shape or configuration, with the cross-sectional shape being limited by the need for the combination chamber  426  to enclose the aerosol holding chamber  412  for compact storage. An additional recirculation passage  434  extends from the attachment end  430  of the combination chamber  426  to the inlet end  416  of the inner portion  412   b  of the aerosol holding chamber  412 , the recirculation passage  434  communicating with the intermediate tube  418  of the inhaler  410  of  FIGS. 9 through 12  by means of the connection of the attachment end  430  of the combination chamber  426  (with the recirculation passage  434  extending therefrom) to the delivery end  416  of the inner portion  412   b  of the aerosol holding chamber  412  and the attachment of the chamber  412  to the intermediate tube  418 . 
   The inhaler  410  of  FIGS. 9 through 12  further includes a plurality of one-way check valves therein, in order to control the flow of air and/or medication through the device. The side elevation view in section of  FIG. 12  illustrates the flow paths through the device, and the locations of the various check valves therein. The check valves may be of any suitable configuration, as described further above in the description of the check valves for the embodiment  110  of  FIGS. 1 and 2 . 
   Air is initially drawn into the aerosol holding chamber  412  through a pair of inlet check valves  436  installed in the side or top of the aerosol holding chamber, particularly in the top of the inner portion  421   b  thereof, simultaneously with the injection of medication into the chamber  412  by means of the MDI or nebulizer N. The aerosol holding chamber inlet check valves  436  are oriented to permit air to flow into the aerosol holding chamber  412 , while blocking outflow. Thus, in the event that pressure within the aerosol holding chamber  412  becomes higher than ambient, air (and medication) cannot escape through the inlet check valves  436 . While two such inlet check valves  436  are illustrated in the inhaler embodiment  410  of  FIGS. 9 through 12 , it should be noted that a single such valve, or more than two such valves, may be incorporated as desired. 
   Air and medication mixed therewith passes from the aerosol holding chamber  412  to the intermediate tube  418  and thence to the user interface device (e.g., the mouthpiece  124  of  FIGS. 1 and 2 , or the face mask  224  of  FIGS. 3 and 4 ) through an intermediate one-way check valve  438  installed at the outlet or delivery end  416  of the aerosol holding chamber  412 . This intermediate valve  438  permits fluid flow from the holding chamber  412  into the intermediate tube  418  and thence into the user interface device, while blocking flow in the reverse direction from the user interface device back into the holding chamber  412 . 
   Any air (and medication) exhaled by the user back through the user interface device passes into the recirculation chamber  426  by way of the attachment end passage(s)  430  thereof connecting the recirculation chamber to the intermediate tube  418 . A recirculation check valve  440  is provided within the recirculation passage  434  where the recirculation passage  434  connects to the aerosol holding chamber  412  (or more precisely, to its inner portion  412   b  adjacent the delivery end thereof), to permit exhaled air and medication to flow back into the aerosol holding chamber  412  for recycling while preventing flow from the holding chamber  412  directly into the recirculation chamber  426  through the recirculation passage  434 . Alternatively, the recirculation check valve may be installed in the attachment end passage(s)  430  of the recirculation chamber  426 , i.e., the inlet side or passage of the recirculation chamber  426 . Such an alternative recirculation valve location is indicated as valve  440   a  in  FIG. 12 . Alternatively, the attachment end cover  431  of the recirculation chamber  426  may include two (or more) passages  430  extending therefrom, with each including a separate one way recirculation check valve  440   a . It will be understood that it is not necessary to provide both recirculation valves  440  and  440   a , as the inlet and outlet passages  430  and  434  of the recirculation chamber  426  comprise a plurality flow, so that only a single recirculation valve  440  or  440   a  may be required at some point in the inlet or outlet side of the recirculation chamber  426 . 
   The above-described system is a one-way system, i.e., no outflow is permitted through any of the passages other than the intermediate tube  418  and any user interface device connected thereto. Accordingly, some means must be provided to vent the device, in order to allow the user to exhale back into the device in order to recirculate air and medication for efficient reuse. This is provided by an outflow check valve  442  located in the distal end  432  of the recirculation chamber  426 , along with an exhalation filter  444  of the general type and properties described further above for the exhalation filter  144  of the inhaler embodiment  110  of  FIGS. 1 and 2 . The distal end  132  and  232  of the embodiments  110  and  210 , with their respective exhalation check valves  142  and  242  and filters  144  and  244 , have been shown in  FIGS. 2 and 4  and discussed further above, and are indicated only generally in the cross-sectional side elevation view of  FIG. 12 . 
     FIGS. 8 through 12  also illustrate the general progression in converting the inhaler  410  from its deployed to its collapsed or stowed configuration for compact storage. The device  410  is shown fully deployed with the rigid combination chamber  426  connected to the intermediate tube  418  in  FIG. 5  and ready for use, with perhaps the only additional component needed being the mouthpiece  124  of the embodiment of  FIGS. 1 and 2  or the face mask  224  of the embodiment of  FIGS. 3 and 4 . The inhaler  410  is collapsed for storage by first telescoping the inner portion or sleeve  412   b  of the aerosol holding chamber  412  the outer portion or sleeve  412   a  of the holding chamber  412 . Air and/or vapor, etc., captured within the aerosol holding chamber  412  as it is collapsed is forced from the holding chamber  412  into the intermediate tube  418  through the intermediate check valve  438 , and thence into the combination chamber  426  through the recirculation check valve  440   a  and out the outflow check valve and filter  442 ,  444 . Normally, a cap or closure (not shown) would be placed over the otherwise exposed user interface connection end  422  of the intermediate tube  418  in order to assure that all vapor contained within the inhaler device  410  remains within the device. 
   Once this has been accomplished, the combination chamber  426  is disconnected from its connections to the intermediate tube  418  and delivery end  416  of the aerosol holding chamber  412  by unplugging the attachment end passages  430  and recirculation passage  434 . This may allow any vapor within the combination chamber  426  to escape, so that it is best to accomplish this step in a location where the release of any vapors can do no harm. Once the combination chamber  426  has been removed from the intermediate tube  418  and aerosol holding chamber  412 , the end passage cap  446  may be installed over the passages  430  and  434  to close the combination chamber  426 . 
   At this point, the combination chamber cover  431  is opened (again, in a suitable location due to the release of vapor contained therein), and the collapsed aerosol holding chamber  412  is inserted into the combination chamber for storage therein. The MDI with its canister C or the nebulizer N will have been removed previously from the medication dispenser end  414  of the aerosol holding chamber, as shown in  FIG. 10  of the drawings. The combination chamber cover  431  is closed over the end of the combination chamber  426  to complete the storage of the device. 
   It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.