Abstract:
A pneumatic inhaler that is able to deliver a controlled burst or dose of aerosol from a reservoir of liquid medication. The inhaler is suitable for the aerosolization of liquid medication that is in solution or suspension form. The inhaler is also ideal for the delivery of unique and specialty liquid medications in short aerosol bursts because no additional formulation development is needed and has the further advantage of being able to deliver multiple medications, as mixed by the patient, doctor, or pharmacist, with a single burst at a repeatable output. Because medication and propellant are not mixed until aerosolization occurs, the inhaler is appropriate for more pharmaceutical agents than the current inhalers available and at a substantial cost savings.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of U.S. application Ser. No. 09/963,886 filed on Sep. 25, 2001, now U.S. Pat. No. ______ incorporated herein by reference, which in turn claims priority to U.S. provisional application serial No. 60/235,597 filed on Sep. 25, 2000, incorporated herein by reference, and from U.S. provisional application serial No. 60/305,088 filed on Jul. 12, 2001, incorporated herein by reference. 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable  
         INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC  
         [0003]    Not Applicable  
         NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION  
         [0004]    A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or records, but otherwise reserves all copyright rights whatsoever. The copyright owner does not hereby waive any of its rights to have this patent document maintained in secrecy, including without limitation its rights pursuant to 37 C.F.R. § 1.14.  
         BACKGROUND OF THE INVENTION  
         [0005]    1. Field of the Invention  
           [0006]    This invention pertains generally to aerosol generating devices, and more particularly to inhalers which may be used to dispense liquid medication in short bursts of aerosol.  
           [0007]    2. Description of the Background Art  
           [0008]    Some medicines cannot withstand the environment of the digestive tract and must be delivered to the bloodstream intravenously or by some other means. One effective means for delivery of such medications to the blood stream is through the membranes and air passageways of the lung.  
           [0009]    Inhalers of various types have been widely used for inhalation delivery of aerosols containing medication or other constituents to the conductive airways of the lung and the gas exchange regions of the deep lung. Aerosols are relatively stable suspensions of finely divided droplets or solid particles in a gaseous medium. When inhaled, aerosol particles may be deposited by contact upon the various surfaces of the respiratory tract leading to the absorption of the particles through the membranes of the lung into the blood stream and providing the desirable therapeutic action, or planned diagnostic behavior depending on the particular properties of the particles.  
           [0010]    Because of the high permeability of the membranes of the lung and the copious flow of blood through the lung, medications deposed in the lung can readily enter the blood stream for action throughout the body. This may also allow for lower initial doses than would be required to be taken orally to achieve the desired concentration of medication in the blood. Other medications can directly influence the airway epithelium and effect responses via various airway receptors.  
           [0011]    Properly generated and formulated aerosols can therefore be helpful in medical treatment. Inhalable aerosol particles capable of deposition within the lung are those with an aerodynamic equivalent diameter between 1 and 5 micrometers.  
           [0012]    Still other types of aerosol particles deposited in the lung can act as tracers of airflow or indicators of lung responses and otherwise be a valuable diagnostic tool.  
           [0013]    An inhaler produces a burst of aerosol consisting of fine particles intended for inhalation by a patient with a single breath. Inhalers are popular aerosol delivery devices because they are generally portable and are convenient to use. The particle size of the aerosol emitted from a typical inhaler is required to be considerably smaller than a conventional spray atomizer to ensure the appropriate deposition within the lungs. Atomizers are typically equipped with reservoirs, nozzles, and bulbs. Upon squeezing the bulb, liquid medication, which is placed within the reservoir, is entrained and sprayed by the nozzle for inhalation by the patient. However, the particle size produced by atomizers is too large for effective deposition in the lungs, although variants of the technique are still used for deposition of topical medication into the nasal cavity and associated tissues. A further disadvantage of atomizers is that they are unable to deliver a consistent dose due to discrepancies in user technique and the duration of each burst. Accordingly, atomizers are appropriate for delivery of medication to the sinus cavity, where the larger aerosol particle size is more effective for deposition but inappropriate for deposition in the deep lung.  
           [0014]    Inhalers known in the art employ several techniques to achieve effective aerosolization of medicines for deposition in the lung. Commonly, inhalers are pre-packaged containers containing a mixture of medication to be aerosolized and a low saturation pressure vapor or gas, such as chlorofluorocarbons (CFCs), which are used as a propellant. The canister carrying the mixture of medication and propellant is equipped with a valve. When the valve is actuated, the inhaler dispenses a set amount of liquid and medication through a jet orifice, creating a spray. Upon release into the atmosphere, the low saturation pressure propellant is able to evaporate quickly leaving small aerosol particles of medication that are suitable for immediate inhalation. One disadvantage to this approach is that the propellant and the medication must be mixed for a significant period of time prior to inhalation by the patient, making them unsuitable for many medications. Furthermore, the pre-mixing of the medication and the propellant requires a different approach to gain regulatory approval, necessitating significant development time and capital, thereby significantly increasing the ultimate cost to the patient than with liquid formulations of same medication. To prevent agglomeration of the medication within the canister, surfactants are also added to the formulation, which often leave an undesirable taste in the mouth of the patient after inhalation.  
           [0015]    Another inhaler strategy increasingly being employed is the aerosolization of dry medicament powders. Medicinal powders are prepared in advance and placed in a reservoir within the inhaler, or within blister pouches. Blister pouches have the advantage of being able to better preserve the powder from contamination and moisture. When the patient is ready for a dose of medication, they either access the reservoir to dispense an appropriate amount of powdered medication, or puncture a blister pouch containing the powder medicament. Aerosolization is typically achieved by the gas flow produced by the inhalation of the patient. However, the aerosolization of medicinal powders is plagued by problems of moisture contamination and the inconsistencies in inhalation effort by the patient from dose to dose. Furthermore, powder formulations are as expensive to develop as pre-mixed propellants.  
           [0016]    A third inhaler strategy employs ultrasonic energy to aerosolize bursts of liquid medication. These devices require precise electronic valves and associated electronic circuitry, making them expensive to manufacture and prone to malfunction. Additionally, the particle size of the aerosol produced by these devices is often too large for optimal deposition in the lung.  
           [0017]    Therefore, a need exists for a technology which can deliver aerosol bursts of liquid medication at a particle size that is appropriate for lung deposition and which is inexpensive for the patient, produces consistent output, uses a formulation which is inexpensive to develop and produce, that is reliable, that is easy to use, and which does not require the mixing of medication and propellant until the moment of aerosolization. The present invention satisfies this need, as well as others and has the further advantages of providing superior aerosol quality, and being lightweight and portable.  
         BRIEF SUMMARY OF THE INVENTION  
         [0018]    The present invention generally pertains to a pneumatic inhaler that is able to deliver a controlled burst or dose of aerosol from a reservoir of liquid medication. The invention is appropriate for the aerosolization of liquid medication that is in solution or in suspension form. The invention is also ideal for the delivery of unique and specialty liquid medications in short aerosol bursts because no additional formulation development is needed. The apparatus has the further advantage of being able to deliver multiple medications, as mixed by the patient, doctor, or pharmacist, with a single burst of aerosol at a repeatable output. Because the medication and the propellant are not mixed until aerosolization occurs, the current invention is appropriate for more pharmaceutical agents than can be used by currently available inhalers at a substantial cost savings.  
           [0019]    By way of example and not of limitation, a first embodiment of the present invention employs a cartridge or cylinder for containing virtually any type of compressed gas. Typically, carbon dioxide gas is used at a preferred pressure of approximately 750 psi, because the gas has a low critical temperature and pressure, allowing a small canister to carry significantly more than if filled with many other gases. The compressed gas is released in small bursts by a valve actuated by the patient, which delivers the gas to the supersonic shock nozzle. The nozzle comprises a jet orifice from which the compressed gas discharges into a sonic shock chamber. Provided that substantial backpressure is supplied, a supersonic jet exits from the jet orifice of the nozzle, which may be over expanded, under expanded or perfectly expanded. If the jet is over or under expanded, the supersonic jet, which remains at approximately the diameter of the jet orifice and which travels down the axis of the shock chamber, establishes a series of reflected compression and expansion shock waves. A perfectly expanded jet will have a cylindrical shock wave that envelops the entire jet. Although this would be preferable for the production of aerosol, it is impractical as a result of changes in supply pressure and the desired dimensional scale of the preferred embodiment of the current invention. Therefore, the nozzle is designed to be over expanded, and this is considered optimum.  
           [0020]    Upon formation of the jet and the resulting reflected shock waves in the shock chamber, a vacuum is generated which causes liquid from the reservoir to be entrained through the liquid feed channels into the shock chamber. The preferred design channels the incoming fluid circumferentially around the shock chamber. Upon entrainment of the liquid into the shock chamber, the initially entrained liquid comes in contact with the shear forces created by the shock waves, producing copious amounts of aerosol particles suitable for inhalation. Shock waves are uniquely able to produce tremendous quantities of aerosol with good particle size for inhalation because they have the property of having large pressure differences over very small distances, thus making them able to generate substantial shear forces. The result of liquid traveling across this shock boundary is to be violently and physically disturbed, thus disintegrating into a dense burst of aerosol with appropriate particle size for inhalation. This represents a significant advance over traditional atomizers, which lacked the ability to produce shock waves of any design or magnitude, resulting in lower output and larger particle size.  
           [0021]    Once the liquid has been entrained into the shock chamber and jet, the integrity of the jet and resulting reflecting shock waves is destroyed, resulting in a reduction in the subsequent production of aerosol particles than is produced in the initial burst. The subsequent production also has a generally larger particle size than the initial burst. The overall result is an initial burst of aerosol ideally suited for an inhaler, generally lasting less than a second. The output and particle size of such an inhaler is substantially better than would be predicted from the steady state operation of an atomizer or nebulizer nozzle of similar design. It is not possible to employ the same technique in the design and manufacture of an atomizer or nebulizer, because these devices are intended to run for durations of time longer than the first initial moments and the unique phenomena of the current invention only occurs at the moment of introduction of fluids to the reflected shock waves. Since the majority of aerosolization takes place in the first moment of liquid entrainment, little compressed gas is required for a burst of aerosol, making it possible, and efficient, to store enough carbon dioxide in a small canister for 200 bursts or more.  
           [0022]    Although not of optimum design under most conditions, a similar result is obtained by having a shock region instead of a shock chamber. In such a design, the jet exits directly into a generally unenclosed region allowing the formation of reflected shock waves within the exiting jet. Liquid is entrained through one or more feed tubes placed proximally to the jet at a sufficient distance to generate a vacuum. Again, once the entrained liquid comes into contact with the reflected shock waves, a tremendous amount of aerosol particles are produced, and the integrity of the sonic jet and the shock waves is destroyed. Based on experimentation, such an approach was not found to be optimum because it did not allow for the precise introduction of fluid to the shock waves, which affects the output and particle size of the resulting aerosol burst. It should be noted that such an open design does have distinct advantages for thick, viscous fluids, because of the potential of clogging involved with the closed design, above first mentioned.  
           [0023]    The preferred embodiment of the current invention draws liquid from a reservoir of medication that is preferably sufficient to hold 200 doses, and has been shown to produce reproducible doses of liquid medication. In the event that extremely precise dosing is desired, or if a change in dosing is desired from burst to burst, the current invention may be modified to consist of a small reservoir, or multiple small reservoirs, that contain the exact amount of liquid desired for delivery, and which is less than the nozzle will entrain with a given burst. Thus, the output of the inhaler is exactly equal to the contents of the reservoir, and may be easily changed from dose to dose.  
           [0024]    Another approach that has been shown to be quite successful, is the use of blister packs pre-filled with the exact amount of liquid intended for aerosolization rather than the use of a reservoir. Prior to the contents of a blister cell being delivered, a feed tube, which is in fluid communication with the supersonic shock nozzle, is caused to puncture and penetrate the blister cell. Upon actuation of the nozzle, the contents of the blister cell is completely entrained into the shock nozzle and aerosolized. Blister packs also have the added advantage of better preserving medication than multiple dose reservoirs due to the limited exposure of the medication to air prior to aerosolization.  
           [0025]    A complete discussion of the requirements for over, under, and perfectly expanded supersonic jets may be found in a text on compressible fluid dynamics. In general, the minimum pressure required to achieve supersonic flow in a nozzle is dependant upon the ambient discharge pressure and the supply pressure such that the ratio of the two should preferably be at least 0.5283 for air or oxygen and 0.5457 for carbon dioxide. Since all known inhalers have always discharged into roughly atmospheric conditions (14.7 psi), the resulting minimum supply pressure can be determined as being approximately equal to 27.8 psi or 13.1 psig for air or oxygen and 26.9 psi or 12.2 psig for carbon dioxide. In theory, these minimum supply pressures are sufficient to produce a flow of gas through the throat of a nozzle with a velocity equal to the speed of sound. In practice, higher pressures are required due to pressure losses and the expansion of gas into the internal volume of the device between the supply canister containing the stored gas and the choke of the nozzle. Although lower pressures above the calculated minimums will produce a degree of aerosolization, superior results are achieved with even higher pressures or continual increases in output for higher pressures. The increase in output for higher pressures is due to the increasing speed of the supersonic jet and the resulting increase in strength of the resulting shock waves. In the current embodiment of the invention, the pressure vessel is preferably filled with carbon dioxide to a pressure of approximately 750 psig, and the valve mechanism is designed to deliver a set amount of carbon dioxide with each actuation thereby controlling the repeatability of each dose and insuring that aerosol exiting the inhaler is produced primarily during the first few moments of contact between entrained liquid and the supersonic jet.  
           [0026]    Supersonic jets produce shock waves in part because the jets don&#39;t expand gradually to the diameter of the shock chamber. Due to the nature of the fluid dynamics involved, and conservation of momentum, supersonic jets expand by producing shock waves, thus producing an extreme change in pressure from one side of a shock wave to the other. Unlike other exiting flow patterns, supersonic jets, through the dynamics of the shock waves, maintain roughly the same diameter that the jets had as they exited from the nozzle from which the jets were produced. Similarly, vacuum and entrainment of liquid is not primarily due to the Bernoulli principle, but more to boundary layer friction between the exiting jet and the surrounding gas in the shock chamber.  
           [0027]    Any nozzle (orifice) which supplies a compressed gas to the nozzle at pressures above the calculated minimums will have a supersonic jet exiting from it which is either over, under, or perfectly expanded, provided that there is nothing present to disturb the jet, such as a liquid. A nozzle may achieve a velocity greater than the speed of sound if it is supplied with sufficient supply pressure and has a gradually increasing cross-sectional area downstream of the throat or choke. The potential increase in velocity with increasing cross-sectional area is dependant on the total supply pressure. For the perfectly expanded supersonic jet, the cross-sectional area is increased to the maximum possible for the given supply pressure, resulting in a supersonic jet with a shock wave entirely enveloping the jet. Although this is ideal for the production of aerosol, it is impractical in practice because of variance in the supply pressure and the dimensional tolerances required.  
           [0028]    An under expanded supersonic jet has a maximum cross-sectional area which is less than the perfectly expanded supersonic jet. The extreme example of an under expanded jet is a simple orifice with no increasing cross sectional area. The result of a under expanded supersonic jet is a series of expansion and compression reflected shock waves, with the first shock waves immediately after the exit of the jet being expansion waves.  
           [0029]    An over expanded supersonic jet has a maximum cross sectional area which is greater than the maximum cross sectional area of the perfectly expanded supersonic jet. The result is also a series of reflected compression and expansion shock waves. In the preferred embodiment, an over expanded supersonic jet is instigated by placing a large radius on the exit edge of the nozzle. Upon the jet traveling through the jet and then subsequently along the radius, the initial response is for the jet to increase to a speed greater than the speed of sound followed by an over expansion of the jet, which will produce reflected shock waves. An over expanded supersonic jet has the slight advantage over an under expanded supersonic jet in that the first reflected shock waves emanating from the exit plane of the jet are compression waves and not expansion waves. In general, compression waves produce higher shear forces and thus would be expected to produce more aerosol and a smaller particle sizes.  
           [0030]    Once the entrained liquid is aerosolized, the momentum of the jet carries the aerosol into a mouthpiece for immediate inhalation by the patient. Depending on the ability of the patient to coordinate actuation and inhalation, and the desired portion of the lung targeted for deposition, a spacer or valved holding chamber may be attached to the mouthpiece. Spacers and chambers allow for easier coordination of patient&#39;s inhalation with device actuation, baffle out larger aerosol particles which are inappropriate for deposition within the lung, and allow more time for the liquid aerosol particles to evaporate, producing superior sized aerosol particles (1-3 microns) for deposition in the alveolar portions of the lung.  
           [0031]    In accordance with another embodiment of the invention, a valve design is provided which is easier and less expensive to manufacture than in the previous embodiments. This embodiment includes a built in valved chamber for storing aerosol during inhalation, in contrast to the previous embodiments that allow for a chamber to be attached when desired. However, the invention is not limited to the use of a valved chamber or specific valve design.  
           [0032]    The valved chamber stores aerosol upon actuation for subsequent inhalation in this embodiment. As is well known in the industry, and recently reported during in-vitro investigations (Respiratory Care, June 2000, Volume 45, Number 6, “Consensus Conference on Aerosols and Delivery Devices”, page 628), valved chambers often maintain a static electric charge due to rinsing with water that causes a significant loss of aerosol particles due to mutual static electric attraction. This embodiment employs an anti-static plastic that prevents this phenomenon from occurring.  
           [0033]    In addition to the properties described in the previous embodiments, the aerosolization process can be further optimized through placement of a liquid feed choke between the fluid reservoir containing the medication, and the liquid feeds that lead into the shock chamber. By further choking the flow of liquid down, it is possible to better control the introduction of fluid into the supersonic jet produced in the shock chamber, thus allowing for better aerosolization and an increase in the duration of the aerosol burst, although it is still a momentary phenomena relative to normal jet nebulization technologies.  
           [0034]    Additionally, the shock wave aerosolization process functions remarkably well with micronized powder in blister packs as well. Blister packs, containing one or more cells, are used to store a pre-determined amount of liquid or powder. Prior to aerosolization, a feed tube, which is in fluid communication with the shock wave aerosolization process nozzle, is inserted into the blister pack cell. Subsequent to the insertion of the feed tube, the carbon dioxide valve is actuated, creating a set burst of gas. As previously described, the carbon dioxide exits the throat of the jet, causing a vacuum, which entrains the micronized powder or liquid through the feed tube and into the shock chamber. As previously described with liquid medication, when medicinal powder is entrained it becomes efficiently aerosolized in the reflected shock waves and carried out to the mouthpiece or valve chamber, as intended.  
           [0035]    An object of the invention is to provide an inhaler, which can deliver a repeatable dose of aerosol containing particles appropriately sized for deposition within the patient&#39;s lung.  
           [0036]    Another object of the invention is to provide an inhaler, which can produce aerosol particles appropriate for deposition in the bronchial airways.  
           [0037]    Another object of the invention is to provide an inhaler, which can produce aerosol particles appropriate for deposition in the alveolar portions of the lung.  
           [0038]    Another object of the invention is to provide an inhaler, which can aerosolize an aqueous solution.  
           [0039]    Another object of the invention is to provide an inhaler, which can aerosolize a suspension of medication in liquid.  
           [0040]    Another object of the invention is to provide an inhaler, which can aerosolize liquid pharmaceutical formulations currently available only for nebulizers.  
           [0041]    Another object of the invention is to provide an inhaler, which does not mix medication and propellant prior to aerosolization.  
           [0042]    Another object of the invention is to provide an inhaler, which can deliver combinations of different medications with one burst.  
           [0043]    Another object of the invention is to provide an inhaler with an acceptable aftertaste.  
           [0044]    Another object of the invention is to provide an inhaler, which is portable, convenient and easy to use.  
           [0045]    Another object of the invention is to provide an inhaler, which is inexpensive to produce.  
           [0046]    Another object of the invention is to provide an inhaler that has a built in valved chamber for storage of aerosol.  
           [0047]    Another object of the invention is to provide an invention that works in conjunction with blister packs that contain either liquid or powder.  
           [0048]    Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein, the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)  
       [0049]    The invention will be more fully understood by reference to the following drawings that are for illustrative purposes only:  
         [0050]    [0050]FIG. 1 is a side view of an embodiment of an inhaler according to the present invention.  
         [0051]    [0051]FIG. 2 is a perspective view of the inhaler of FIG. 1.  
         [0052]    [0052]FIG. 3 is a side view in cross-section of the inhaler of FIG. 1.  
         [0053]    [0053]FIG. 4 is a perspective view of the actuator portion of the inhaler of FIG. 1.  
         [0054]    [0054]FIG. 5 is a side view in cross-section of the actuator of FIG. 4.  
         [0055]    [0055]FIG. 6 is a side view in cross-section showing the valve portion of the actuator of FIG. 4 in the actuated state.  
         [0056]    [0056]FIG. 7 is a perspective view of the aerosol generator portion of the inhaler of FIG. 1.  
         [0057]    [0057]FIG. 8 is a side view in cross-section of the aerosol generator of FIG. 7.  
         [0058]    [0058]FIG. 9 is a detail side view in cross-section view of the nozzle portion of the aerosol generator of FIG. 7.  
         [0059]    [0059]FIG. 10 is a front view of aerosol generator of FIG. 7.  
         [0060]    [0060]FIG. 11 is a rendering of an over expanded supersonic jet used in the inhaler of FIG. 1.  
         [0061]    [0061]FIG. 12 is a schematic representation of the over expanded supersonic jet of FIG. 11.  
         [0062]    [0062]FIG. 13 is an exploded view of a second embodiment of an inhaler according to the present invention showing the reusable actuator handle, aerosol generator, and carbon dioxide cartridge.  
         [0063]    [0063]FIG. 14 is a perspective view of the disposable carbon dioxide refill cartridge portion of the inhaler of FIG. 13.  
         [0064]    [0064]FIG. 15 is a exploded view of the carbon dioxide canister of FIG. 14.  
         [0065]    [0065]FIG. 16 is a perspective view of the reusable inhaler actuator portion of the inhaler of FIG. 13.  
         [0066]    [0066]FIG. 17 is a exploded view of the reusable actuator of FIG. 16.  
         [0067]    [0067]FIG. 18 is a perspective view of the valve portion of the inhaler of FIG. 13.  
         [0068]    [0068]FIG. 19 is a exploded view of the valve of FIG. 18.  
         [0069]    [0069]FIG. 20 is a side view in cross-section view of the valve of FIG. 18.  
         [0070]    [0070]FIG. 21 is a perspective view of the disposable inhaler aerosol generator portion of the inhaler of FIG. 13.  
         [0071]    [0071]FIG. 22 is a exploded view of the aerosol generator of FIG. 21.  
         [0072]    [0072]FIG. 23 is a top view of the jet employed in the inhaler of FIG. 13.  
         [0073]    [0073]FIG. 24 is a top view of the secondary employed the inhaler of FIG. 13.  
         [0074]    [0074]FIG. 25 is a bottom view of the secondary of FIG. 24.  
         [0075]    [0075]FIG. 26 is a perspective view of the cap employed in the inhaler of FIG. 13.  
         [0076]    [0076]FIG. 27 is a perspective view of the column base employed in the inhaler of FIG. 13.  
         [0077]    [0077]FIG. 28 is a perspective view of the end of the column of FIG. 27.  
         [0078]    [0078]FIG. 29 is an assembled perspective view of the inhaler of FIG. 13.  
         [0079]    [0079]FIG. 30 is a side view in cross-section of the inhaler of FIG. 29.  
         [0080]    [0080]FIG. 31 is a detail side view in cross-section of the supersonic nozzle assembly portion of the inhaler of FIG. 13.  
         [0081]    [0081]FIG. 32 is a detail side view in cross-section of the jet and shock chamber portion of the nozzle assembly of FIG. 31.  
         [0082]    [0082]FIG. 33 is a side view in cross-section of an embodiment of an inhaler according to the present invention employing a disposable cartridge containing both the nozzle and a blister pack of medication. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0083]    [0083]FIG. 1 through FIG. 3 show the overall configuration of an embodiment of a shock wave aerosolization apparatus according to the present invention is shown. The inhaler portion of the apparatus comprises two primary parts; an actuator  12  shown in FIG. 4, FIG. 5, and more specifically in FIG. 6, and an aerosol generator  14  shown in FIG. 7, FIG. 8 and more specifically in FIG. 9 and FIG. 10. FIG. 11 and FIG. 12 are for illustrative purposes regarding the nature of reflected shock waves in a supersonic jet. FIG. 13 and FIG. 29 show the overall configuration of a second embodiment of the invention. FIG. 14 and FIG. 15 show the gas canister assembly. FIG. 16 through FIG. 20 detail the actuator handle assembly and FIG. 21 through FIGS. 28, 31 and  32  shows the aerosol generator assembly of the second embodiment. FIGS. 29 and 30 shows the configuration of the apparatus during use. FIG. 33 shows a third embodiment of the invention employing a supersonic shock nozzle assembly enclosed in a small disposable cartridge along with a single blister pack  352  containing sufficient medication for one aerosol treatment. It will be appreciated that the embodiments of the apparatus may vary as to configuration and as to details of the parts, and that the method may vary as to details of steps and their sequence, without departing from the basic concepts as disclosed herein.  
         [0084]    Referring now to FIG. 1, the aerosolization apparatus  10  of the present invention generally includes an actuator  12  and an aerosol generator  14 . The actuator  12  and the aerosol generator  14  are separable components in the embodiment shown, however, it will be understood that these components may be fully integrated and inseparable.  
         [0085]    As seen in FIG. 2 and FIG. 3, the actuator  12  of apparatus  10  has a handle  16  that is preferably configured to fit in the notch between the thumb and first finger of the hand of the user. In the embodiment shown, the actuator  12  has a trigger  18  that pivots about trigger pin  20  and is brought toward the body of actuator  12  by the fingers of the user to actuate the device. The actuator  12  also has a cap  22  that can be removed from the body of the actuator  12  as needed.  
         [0086]    The aerosol generator  14  is operably coupled with actuator  12  and provides aerosolized medications to a user through a mouthpiece  24  when the trigger  18  is depressed. Medicine is disposed within a reservoir through a port that is sealed with a plug  26 .  
         [0087]    Turning now to FIG. 3, a cross section of the apparatus  10  with the actuator  12  coupled with the aerosol generator  14  is shown. The primary components of the actuator  12  are the handle  16 , cap  22 , carbon dioxide canister  28 , trigger  18 , valve body  30 , valve poppet  32 , and valve spring  34 . Carbon dioxide canister  28  is disposed within handle  16  and is held in place by cap  22 .  
         [0088]    The primary components of the aerosol generator  14  are reservoir  38 , mouthpiece  24 , aerosolization nozzle  36  and plug  26 . It can be seen that canister  28  provides a source of supply of gas to the aerosol generator  14  that is regulated by poppet  32 . Gas from the canister  28  is directed through the aerosolization nozzle  36 , mixed with medicine from reservoir  38  and out through the mouthpiece  24  to the user.  
         [0089]    Referring also to FIG. 4 and FIG. 5, the aerosol generator  14  is releasibly coupled with the actuator  12 . The aerosol generator  14  component can be quickly removed from the actuator  12  for refilling and cleaning. Likewise, different medications can be administered sequentially to a single patient by removing the first aerosol generator  14  after the first dosage is administered and replacing it with a second aerosol generator  14  that has a different medication. Thus, it can be seen that a practitioner can administer appropriate medications to any number of patients using one actuator  12  and aerosol generators  14  specially prepared for each patient.  
         [0090]    Turning now to FIG. 4, FIG. 5 and more specifically FIG. 6, actuator  12  is shown without the aerosol generator  12  in place. The actuator  12  is a source of gas supply that can be regulated by the actions of poppet  32 . When cap  22  is removed from handle  16 , carbon dioxide canister  28  can be placed into cap  22  and then inserted into the internal space of handle  16 . With the tightening of cap  22 , carbon dioxide canister  28  is caused to be punctured by hollow prong  40 , which is part of valve body  30 , and thereafter the canister is sealed against canister o-ring  42 .  
         [0091]    Once punctured and sealed, carbon dioxide canister  28  is in fluid communication with valve poppet  32  disposed within valve poppet chamber  46  through canister conduit  44  within hollow prong  40  and the wall of valve body  30 .  
         [0092]    Valve poppet  32  comprises a trigger head  48  with an actuating cam surface  50  that smoothly engages trigger  18  through the full range of motion of the trigger pull. The poppet  32  is biased to the far left or “rest” position, as shown, by spring  34 , such that shoulder  54  is caused to rest against stop plate  56 . Spring  34  preferably fits within spring indent  58  at the distal end of poppet  32 .  
         [0093]    The valve poppet in the activated position is shown in FIG. 6. It will be seen that valve poppet  32  is caused to move to the right, or “actuated” position, when trigger  18  is squeezed, resulting in force being applied to actuating cam surface  50  of trigger head  48  of poppet  32  in opposition to the force of valve spring  34 .  
         [0094]    The body  52  of poppet  32  preferably has a first o-ring groove  60 , a second o-ring groove  62 , and a third o-ring groove  64  that are mated with first o-ring  66 , second o-ring  68 , and third o-ring  70  respectively. The poppet body  52  also has a charging volume groove  72 , preferably positioned between the second o-ring groove  62  and the third o-ring groove  64 . First o-ring groove  60 , second o-ring groove  62 , third o-ring groove  64 , and charging volume  72  all consist of geometry which is circumferential to valve poppet  32 , which is generally cylindrical in shape. O-rings  66 ,  68  and  70  are all made preferably of urethane, which is compatible with high-pressure carbon dioxide.  
         [0095]    Although o-rings are preferred, it will be understood that other alternative sealing means known in the art may also be used to eliminate leakage of gas from the canister conduit  44  into poppet chamber  46  and out of the apparatus.  
         [0096]    Referring more particularly to FIG. 5, it can be seen that when valve poppet  32  is in the rest position, as shown, the internal gas pressure of carbon dioxide canister  28  is in fluid communication with charging volume  72  and the space between poppet  32  and the walls of poppet chamber  46 , between o-rings  68  and  70  through canister conduit  44 , resulting in charging volume  72  being filled with carbon dioxide to the same pressure that is in carbon dioxide canister  28 . The contents of carbon dioxide canister  28 , and charging volume  72 , is prevented from escaping around the valve poppet  32  into the ambient environment primarily by second o-ring  68  and third o-ring  70  that seal the sections of the chamber  46  between the o-rings.  
         [0097]    As valve poppet  32  is moved into the actuated position, as shown in FIG. 6, second o-ring  68  passes over canister conduit  44 , preventing further fluid communication between carbon dioxide canister  28  and charging volume  72 , and third o-ring  70  is caused to pass over valve exit conduit  74 , thus releasing the pressurized gas in charging volume  72  through valve exit conduit  74  to valve exit port  76 . Second o-ring groove  62  and third o-ring groove  64  are preferably spaced apart from charging volume  72  so that the second o-ring  68  terminates fluid communication between carbon dioxide canister  28  and charging volume  72  prior to the third o-ring  70  passing over valve exit conduit  74 , thus preventing the contents of carbon dioxide canister  28  from ever being in fluid communication with valve exit conduit  74  and valve exit port  76 , and creating a burst of pressurized gas to be released from charging volume  72 .  
         [0098]    Obviously, charging volume  72  may be designed for different volumes allowing for different amounts of carbon dioxide being released with each actuation. It will also be seen that first o-ring  66  prevents escape of contents of carbon dioxide canister  28  around valve poppet  32  into the ambient environment when valve poppet  32  is in the actuated position.  
         [0099]    As shown in FIG. 1, FIG. 2, and FIG. 3, aerosol generator  14  is caused to mate with actuator  12 . As seen in FIG. 7 and FIG. 8, aerosol generator  14  has a pair of locking tabs  78  that pass through corresponding tab slots  80  and snap into tab receptacles  82 , as shown in FIG. 4. When locking tabs  78  on aerosol generator  14  are fitted into tab receptacles  82  of actuator  12 , inlet stem  84  of FIG. 8 is configured to fit to valve exit port  76  of actuator  12  as seen in FIG. 4, FIG. 5, and FIG. 6. Inlet stem  84  is mated with valve exit port  76  of actuator  12  such that sealing is established between the base of inlet stem  84  and actuator outlet o-ring  88  of FIG. 6. This allows for fluid communication between valve exit port  76  of actuator  12  and inlet stem  84  of aerosol generator  14  via valve exit conduit  74  of FIG. 6 and supply inlet  86  of FIG. 8.  
         [0100]    Referring now to FIG. 8, it can be seen that compressed gas from the actuator  12  passes through supply inlet  86  of inlet stem  84  into supply channel  90  and into insert supply cavity  92  and out of the aerosolization nozzle  36  through jet orifice  94 .  
         [0101]    In the embodiment shown, reservoir  38  of aerosol generator  14  preferably has a liquid feed tube  96  mounted to liquid feed stem  98  that has a medicine channel  100  that is in fluid communication with the aerosolization assembly  36  as seen in FIG. 8 and FIG. 9. Thus, liquid entrained for aerosolization is caused to travel up liquid feed tube  98 , medicine channel  100  of liquid feed stem  98  and directly to the nozzle section of the aerosolization nozzle  36 , which is shown in the blown up view of FIG. 9.  
         [0102]    In one embodiment, aerosol generator  14  is made of reservoir base  102 , mouthpiece  104 , elbow  106  and nozzle insert  108  components. In this embodiment, the aerosol generator  14  is assembled by placing liquid feed tube  96  on liquid feed stem  98  of mouthpiece component  104 . Insert  108  is placed into the back of mouthpiece  104  creating the critical nozzle geometry shown in FIG. 9 where aerosolization occurs. Elbow  106  is placed into backside of insert  108  and then the assembly consisting of mouthpiece  104 , insert  108  and elbow  106  are coupled with reservoir base  102 . Plug  26  is then placed into reservoir component  102 . Bonding between mating pieces may be established using press fits, adhesive techniques, or ultrasonic welding, except for mating between plug  26  and reservoir base  102 , which is intended to be a sliding fit.  
         [0103]    Liquid medication intended for aerosolization is placed in reservoir  38  by removing plug  26  and placing the medication directly into the liquid storage cavity of reservoir  38 . Various liquid medications may be placed in the reservoir, as desired. In one embodiment, the liquid storage cavity of reservoir  38 , contains a total volume of at least twice the intended liquid volume to be dispensed. This allows for the prevention of spilling of the contents of the liquid storage cavity of reservoir  38  and for different orientations of the aerosol generator  14 .  
         [0104]    An alternative to having a reservoir  38  for storing of medication for multiple doses, as above described, is to have means by which one dose may be made available to the aerosolization nozzle  36  at a given time. This would be the preferred embodiment of the current invention for medication requiring very strict output control or which requires special handling and storing, such as refrigeration. Strict output control would be realized because the aerosolization assembly  36  is designed so that it always attempts to entrain more liquid than there is present in the single dose reservoir. In this way, output is controlled solely by what is in the reservoir and not the critical dimensions of the aerosolization assembly  36  or the contents of carbon dioxide canister  28 .  
         [0105]    There exists many ways to have single dose reservoirs, including a very small version of the previously described liquid storage cavity  38 , single ampules, or blister packs. A single dose may also include multiple puffs until the medication in the reservoir or ampule is depleted. In the case of ampules or blister pack cells, the liquid feed tube  96  would preferably be made from stiff plastic and would puncture the ampule or blister pack cell when entrainment was desired. After actuation, the empty ampule would be discarded, or, in the case of the blister pack, the liquid feed tube  96  would be advanced to the next blister pack cell when another dose of aerosol was required.  
         [0106]    Still referring to FIG. 8, carbon dioxide gas supplied to supply inlet  86 , is caused to pass up supply conduit  90  and into insert supply cavity  92 . Referring also to FIG. 9, pressurized carbon dioxide gas that is provided to insert supply cavity  92  is caused to pass into jet orifice  94  with exit plane radius  110 . In the preferred embodiment, jet orifice  94  has a diameter ranging from approximately 0.008 inches to approximately 0.016 inches, and exit plane radius  110  preferably has a diameter ranging from approximately 0.010 inches to approximately 0.020 inches. Because the supply pressure of the carbon dioxide canister is normally 750 psig, the jet formed in the jet orifice  94  will go supersonic. The jet will remain supersonic until such time that the cross sectional area of the exit area, due to exit plane radius  110 , becomes too large, at which point the jet will be over expanded and reflected shock waves will form in the jet as shown graphically in FIG. 11 and schematically in FIG. 12. The diamond-shaped patterns of FIG. 11 and FIG. 12 show the shock wave patterns in the jet.  
         [0107]    In the preferred embodiment of the present invention, exit plane radius  110  is large enough to insure that the supersonic jet formed from jet orifice  94  is over expanded. This will cause the first series of reflected shock waves to be compression shock waves and not expansion shock waves. Although expansion shock waves are capable of aerosolization, compression shock waves are preferable and considered slightly more optimum.  
         [0108]    In an alternative configuration in which reflected expansion waves are desired initially, exit plane radius  110  would be made small enough, removed, or replaced with an appropriate taper, so that the exiting supersonic jet from jet orifice  94  was under expanded.  
         [0109]    The supersonic jet exiting the jet orifice  94  and associated exit plane radius  110  will travel axially down shock chamber  112  and into the confines of mouthpiece  24 . In the preferred embodiment, shock chamber  112  has a diameter ranging from approximately 0.020 inches to approximately 0.030 inches, or two to three times the diameter of the jet orifice  94 . The resulting reflecting shock waves will continue along with the jet well outside the exit plane of shock chamber  112 . Optimally, interstitial space  114  has a gap distance between the exit plane and jet orifice  94  and the inlet of shock chamber  112  of between approximately 0.007 inches and 0.016 inches.  
         [0110]    Referring also to FIG. 11 and FIG. 12, upon the initial formation of the supersonic jet, a vacuum will be created in interstitial space  114 , which is in fluid communication with the medicine channel  100 , thus causing liquid medication to be entrained from reservoir  38  through liquid feed tube  96 , stem  98 , channel  100  and introduced into shock chamber  112 . The initial liquid entrained into shock chamber  112  comes in contact with the supersonic jet and the chain of reflected shock waves emanating from jet orifice  94 . Upon contact with the shock waves and the jet, the initial liquid is agitated violently by the large shear forces produced by the shock waves and the discrepancy between the high velocity of the jet and the slow velocity of the liquid, which produces a tremendous burst of aerosol. The aerosol burst is carried out of the shock chamber  112  along with the expelled gas to mouthpiece  24 . Subsequent to the initial fluid being introduced to shock chamber  112 , the integrity of supersonic jet and resulting shock waves are destroyed due to the ongoing entrainment of more liquid, although shock waves are still present immediately proximal to the exit plane of jet orifice  94  and exit plane radius  110 . These remaining shock waves are insufficient for the same production rate of aerosol produced initially due to the smaller exposed area and the location of the waves with respect to ongoing entrainment of liquid.  
         [0111]    Accordingly, the charging volume  72  is preferably made large enough so as to deliver enough carbon dioxide gas to give the jet time to form, entrain liquid, and create the desired burst of aerosol. Once the carbon dioxide that is delivered from charging volume  72  to the jet orifice  94  is depleted, the jet ceases to exist all together, and no more liquid is entrained.  
         [0112]    Referring back to FIG. 8, the aerosol exiting shock chamber  112  is carried into the internal cavity  118  of mouthpiece  24  where it is available for immediate inhalation by the patient. Referring also to FIG. 10, which is a view of aerosol generator  14  looking directly down the internal cavity  118  of mouthpiece  24 , the backside of the internal cavity  118  of mouthpiece  24  is preferably equipped with four entrainment ducts  116 , which allow ambient air to be entrained when the patient inhales. The diameter of the mouthpiece internal cavity  118  and the cross-sectional area of the four entrainment ports  116  are the primary means of controlling the geometry and speed of escaping aerosol  120  from shock chamber  112 .  
         [0113]    The length of the mouthpiece  24  and its internal cavity  118  also plays a role in the speed of escaping aerosol. Accordingly, the length of mouthpiece  24  is reduced to a minimum to prevent as much waste of aerosolized medication  120  as possible. In the current preferred embodiment, the mouthpiece internal cavity  118  has a diameter of approximately 0.775 inches and the preferred cross-sectional area of the four entrainment ducts  116  is approximately 0.08 inches squared or 0.02 inches square for each duct  116 . Reducing the cross-sectional area of the four entrainment ducts  116  has been shown to reduce the exit velocity of the resulting aerosol if desired. Additionally, spacers and valve holding chambers are well known in the industry and can be connected directly to the outer diameter of mouthpiece  24 .  
         [0114]    Referring now to FIG. 13 through FIG. 30, an alternative embodiment of the invention is shown. As shown in FIG. 13, this embodiment comprises three principal parts: a reusable actuator handle  200 , a disposable aerosol generator  202  and a disposable carbon dioxide cartridge assembly  204 .  
         [0115]    Turning now to FIG. 14 and FIG. 15 the carbon dioxide cartridge assembly  204  can be seen. The cartridge assembly  204  comprises a carbon dioxide canister  206  and gas canister cap  208 . The carbon dioxide gas canister  206  includes a top  210  with threads  268  that is configured to engage with corresponding threads  266  within a valve assembly contained in actuator handle  200  as seen in FIG. 14 and FIG. 20.  
         [0116]    Carbon dioxide represents only one of many different types of gases that can be used to power the current invention. Although carbon dioxide gas is preferred, it will be understood that any appropriate pressurized gas can be used. In one embodiment, gas canister  206  is bonded to the gas canister cap  208  with an adhesive and is designed with a large diameter to allow for sufficient torque during insertion of the carbon dioxide cartridge  206  into actuator handle  200 . Carbon dioxide cartridge  206  preferably fits longitudinally into the underside of actuator handle  200  through cartridge port  212 .  
         [0117]    Turning now to FIG. 16 through FIG. 19, the preferred components of the actuator handle  200  are shown. Actuator handle  200  has an elongate actuator body  214  with cartridge port  212  at the bottom end. The actuator handle also includes a valve assembly  216 , valve stem cover  218 , trigger  220 , and trigger pivot pin  222  as seen in FIG. 17.  
         [0118]    Valve stem cover  218  has a pair of valve stem cover bosses  224  that engage angled edges  226  of trigger  220  such that when trigger  220  pivots about pin  222  the valve stem cover  218  moves longitudinally within handle body  214 . Accordingly, when assembled, valve stem cover  218  mates with valve assembly  216  and the bosses  224  engage with trigger  220  such that when trigger  220  is squeezed, trigger cam surface  226  engages with valve stem bosses  224  such that valve stem cover  218  is forced to move downward causing valve assembly  216  to become actuated as described herein.  
         [0119]    Referring now to FIG. 18, FIG. 19 and FIG. 20, the components of the preferred valve assembly are shown. Valve assembly  216  has a generally cylindrical body  228  that is configured to fit within actuator handle  200  as seen in FIG. 17 and FIG. 18. In one embodiment, valve assembly body  216  has one of more raised rails  230  on the outer surface that slide within corresponding slots in the interior of the handle  200  (not shown) as well as slots  232  in valve stem cover  218 . The raised rail  230  and slot configuration securely positions the valve assembly and eliminates any rotational motion of the valve assembly  216  when the threads  268  of the top  210  of gas canister  206  are screwed into the threads  268  of the valve assembly. Rails  230  also facilitate the linear movement of the valve stem cover  218  with respect to the valve assembly  216  when the trigger  220  is pressed.  
         [0120]    Referring now to the exploded view of the valve assembly  216  in FIG. 19 and the cross sectional view of FIG. 20, the regulation of the flow of gas from the canister  206  through the stem exit port  236  can be seen. In the embodiment shown in FIG. 19, the valve assembly  216  has a canister seal  238 , valve body  228 , hollow canister puncture pin  240 , puncture pin valve seal  242 , valve spacer  244 , central valve seal  246 , cylinder  248  with chamber  250 , stem plug  260 , valve stem  234 , top valve seal  252 , and end plate  254 . The exploded view in FIG. 19 shows the relative position of each of these components. The cross sectional schematic view in FIG. 20 shows the relative position of the components when assembled.  
         [0121]    Seals  238 ,  242 ,  246  and  252  as well as stem plug  260  are preferably made of urethane, due to the resistance of this material to compressed carbon dioxide. Valve spacer  244  and cylinder  248  are preferably made of injected molded nylon. Valve body  228 , canister puncture pin  240 , valve stem  234 , and end plate  234  are preferably made of machined aluminum but may also be made of glass-reinforced nylon. In the embodiment shown, the parts are assembled as shown in FIG. 19 and then valve body end  256  is rolled over in a machining operation to keep the parts in place.  
         [0122]    Referring now to FIG. 20, the regulation of the gas flow and the movements of the valve components of one embodiment of the valve assembly can be seen. Valve stem  234  can move axially within chamber  250  of cylinder  248 . A circumferential flange  258  on stem  234  stops the outward movement of stem  234  by engaging the interior side of the top valve seal  252 . Valve stem  234  is tubular and has a plug  260  in the approximate center of the stem. In addition, stem  234  has a valve stem inlet orifice  262  and a valve stem exit orifice  264  that communicate from the interior of the stem  234  to the exterior.  
         [0123]    When the top  210  of carbon dioxide canister  206 , for example, is advanced on threads  266  of the valve assembly body  228 , the top of canister  206  will engage hollow puncture pin  240 , which pierces the top  206 . The top  210  of carbon dioxide canister  206  is caused to seat against canister seal  238  as the threads  269  of canister  206  are advanced along the threads  266  of the valve body.  
         [0124]    Once seated, carbon dioxide becomes available to valve assembly  216  through canister puncture pin orifice  270 . The valve assembly  216  in the normally closed position is shown in FIG. 20. In this position, valve stem  234  is pushed by the pressure of the compressed carbon dioxide gas so that valve stem flange  258  is caused to seal against the upper valve seal  252 .  
         [0125]    In the closed position, carbon dioxide is allowed to pass from the canister  206  through orifice  270 , valve seal  242  and valve spacer  244  to valve stem inlet port  272  located at the proximal end of stem  234 . Gas within stem  234  must exit the stem through inlet orifice  262  because of plug  252  to fill the chamber  250  of cylinder  248  that exists between the outer diameter of valve stem  234  and the inner diameter of valve cylinder  248 . Valve seals  246  and  252  are sized on the internal diameters to fit and seal against the outer diameter of valve stem  234 . In the closed position, chamber  250  ultimately becomes filled with carbon dioxide gas to the same pressure as that of canister  206 .  
         [0126]    In the open position, valve stem  234  is moved in an axial direction, against the force of internal pressure, toward the canister  206 . It will be seen that when stem  234  is moved axially, valve stem inlet orifice  262  is caused to pass by central valve seal  246  thereby disconnecting fluid communication between the carbon dioxide pressure provided by the carbon dioxide cartridge  206  and interstitial space of chamber  250 . Further axial motion of valve stem  234  causes valve stem exit orifice  264  to pass through top valve seal  252  allowing the compressed gas in chamber  250  to exit the chamber through stem exit orifice  264  to the interior of valve stem  234  and out through valve stem exit port  236 . In the preferred embodiment, the volume of gas that is discharged through stem exit port  236  is predictable and consistent for each actuation and is determined by the relative internal volumes of jet  274  and the volume of chamber  248 . When the stem  234  is returned to the normally closed position, the chamber  250  refills and becomes ready for the next actuation.  
         [0127]    Turning now to FIG. 21 through FIGS. 28, 31 and  32 , the preferred aerosol generator component of the present invention is described. As seen in the exploded view of FIG. 22, the preferred aerosol generator  202  comprises a jet  274 , secondary  276 , reservoir cup  278 , cap  280 , column base  282 , column  284 , flapper valve  286 , and column end  288 .  
         [0128]    The jet  274 , shown in FIG. 23, has a set of external threads  300  that allow the aerosol generator  202  to fit onto actuator handle  200  through the engagement of threads  300  with the corresponding threads  302  of valve stem cover  218  as shown in FIG. 16. The distal end of valve stem  234  mates with the inside diameter of valve stem cover  218  to provide an adequate seal. The interior of jet  273  is configured to receive valve stem cover exit port  304  when the external threads  300  of jet  274  is coupled with the valve stem cover  218 . Jet  274  also has a jet orifice  306  that allows the flow of gas received from exit port  236  from valve stem  234  through valve stem cover exit port  304 .  
         [0129]    Jet  274  and the secondary  276  shown in FIG. 24 interlock together such that the external surfaces  308 ,  310  of jet  274  and the internal surfaces of secondary channels  312 ,  314  of secondary  276 , seen in FIG. 25, to form interstitial fluid passages  316 .  
         [0130]    Secondary  276 , shown in FIG. 24 and FIG. 25 also has an opening  318  that operates as a shock chamber. As in the previously described embodiment, jet orifice  306  mates with secondary  276  such that the shock chamber  318  and jet orifice  306  are aligned to form the shock wave aerosolization nozzle, and preferably have the same nozzle dimensions as described in the first embodiment.  
         [0131]    Secondary  276  fits into the bottom of reservoir cup  278  to form a reservoir for the holding of liquid medication such that secondary surface  320 , shown in FIG. 24, preferably becomes the lowest point of the liquid reservoir. Penetrating through surface  320  through to secondary channel  314  is liquid choke orifice  322 . Liquid choke orifice  322  provides further means, through the resistance of the flow of liquid, for limiting the rate and amount of liquid entrained by the shock wave aerosolization nozzle. The preferred optimum size range for liquid choke orifice  322  is less than approximately 0.050 inches.  
         [0132]    Reservoir cup  278  mates with cap  280  through the engagement of locking clips  324  on reservoir cup  278  shown in FIG. 22 with locking members  326  as shown in FIG. 26. Reservoir cup  278  and cap  280  are designed to allow the exit plane of secondary  276  to protrude through a bore  330  in cap  280  allowing for aerosol entry directly into aerosol chamber  340 , while creating at the same time anti-spill ability for reservoir  332  as shown in FIG. 30. Anti-spill reservoir volume  332 , shown in FIG. 30 is designed such that when invention is tipped sideways or upside down, liquid in reservoir does not spill out.  
         [0133]    As seen in FIG. 26, cap  280  is preferably equipped with two pairs of protruding ribs  328  located on opposite sides of the cap which allow for column base  282  and spacer column  284  to slide over cap  280  without rotating.  
         [0134]    Column base  282 , shown in FIG. 27, is equipped with mouthpiece  334  to allow for patient inhalation. Column  284  is preferably tubular and configured to fit onto column base  282 . Column base  282 , column  284 , and column end  288  are preferably all made of anti-static plastic material to prevent the loss of charged aerosol particles due to the attraction of the particles to oppositely charged aerosol chamber surfaces.  
         [0135]    Referring now to FIG. 22 and FIG. 28, flapper valve  286  is preferably a thin rubber circular piece that has a center hole which fits over flapper valve post  336  of column end  288 . Flapper valve  286  preferably has a large enough outer diameter to encircle inhalation ports  338 . Column end  288  fits onto column  284  to form an aerosolization chamber  340 .  
         [0136]    Once aerosol is produced from the jet  274  and shock chamber  318 , it enters into the aerosolization chamber  340  of column  284  where it is stored until patient inhales on mouthpiece  334 . Flapper valve  286  prevents the patient from forcing stored aerosol out of chamber with an accidental exhalation. Upon inhalation, flapper valve  286  allows room air to be entrained into chamber  340 .  
         [0137]    Referring now to FIG. 29 and FIG. 30, the completed coupling of the aerosol generator  202 , the actuator handle  200  and the gas canister assembly  204  can be seen. The apparatus can be conveniently stored in two pieces that are coupled prior to use.  
         [0138]    Referring also to FIG. 31 and FIG. 32, the full structure of the preferred alternative embodiment of the apparatus can be seen. In use, gas from canister  206  that has been previously seated on canister seal  238 , enters the valve assembly  216  through pin orifice  270 . Gas enters chamber  250  through valve stem inlet port  272  and valve stem inlet orifice  262  until the pressure of the gas in chamber  250  is equal to the pressure of the gas in canister  206 . Upon actuation of trigger  220  as previously described, the contents of chamber  250  exit through valve stem outlet orifice  264  and valve stem outlet port  236  as a burst of gas. The burst of gas travels through the internal conduit  342  of the valve stem cover  218 , and into the interior  344  of jet  274 . Jet orifice  306  is dimensioned so that the jet formed in the jet orifice  306  will be supersonic producing the aerosolization process as described in the first embodiment.  
         [0139]    Additionally, jet orifice  306 , exit plane radius  348  and shock chamber  318  preferably have the same dimensions and performance characteristics as the first embodiment described herein.  
         [0140]    Medicine held in reservoir  332  enters choke port  322  and channels  312  and is drawn to interstitial space  346  between the jet  274  and secondary  276  and aerosolized when brought in contact with the supersonic jet. The aerosolized medication is then contained in the interior chamber  340  of column  284  for inhalation by the patient.  
         [0141]    In accordance with a still further embodiment of the invention, as shown in FIG. 33, the equivalent of jet  274  and secondary  276 , forming the supersonic shock nozzle assembly, can be enclosed in a small cartridge  350  along with a single blister pack  352  containing sufficient medication for one aerosol treatment. In this single use embodiment, the cartridge  350  is to be inserted into the base of the column  282  that is coupled to the body  214  of actuator handle  200  so as to cause the supersonic shock nozzle to become oriented above the channel  342  of valve cover port  304 . Cartridge  350  has an exterior housing  354  that is configured to be disposed in a slot within the base  282  as needed by the patient. After insertion into the base, cartridge  350  is sealed to the outlet passage of carbon dioxide with o-ring  356 .  
         [0142]    The shock nozzle assembly has a jet orifice  358  and a shock chamber  360  that are preferably configured as described in the previous embodiments. Adjacent to jet orifice  358  is liquid feed line  362  that is in fluid communication with prong  364 .  
         [0143]    Simultaneous with insertion of the cartridge  350 , the foil barrier  370  of blister pack  352  is preferably punctured by the prong  364  by pressing a button  368  and the medicine  366  within blister pack  352  is capable of being entrained from the blister pack  352  through liquid feed tube  362  and through to the supersonic shock nozzle. Aerosol is directed to chamber  340  from the supersonic shock nozzle for inhalation by the patient. Accordingly, as gas is caused to pass through the jet orifice  358  and shock chamber  360 , the medicine  366  in the blister pack  352  is entrained and aerosolized by the supersonic shock nozzle as in the previous embodiment. Upon completion of the aerosol treatment, the supersonic shock nozzle/blister cartridge  350  may be removed and discarded by the user. This single use embodiment may work with or without an aerosol storage chamber and has the advantage of reducing possible contamination of the supersonic shock nozzle between treatments.  
         [0144]    It can be seen, therefore, that the present invention provides an inhaler device that can deliver a burst of aerosol from an aqueous solution. In this way a number of advantages are realized which include, less expense on the part of the patient, less cost in formulation development, better aftertaste, portability, and convenience.  
         [0145]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural, chemical, and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C.  112 , sixth paragraph, unless the element is expressly recited using the phrase “means for.”