HK1097782B - Synthetic jet based medicament delivery method and apparatus - Google Patents

Description

Synthetic jet based drug delivery method and device

Technical Field

The present invention relates generally to the field of metering, packaging and delivery of pharmaceuticals and medicines. The invention is particularly useful for delivering metered and packaged dry powder medicaments and medicaments for inhalation therapy and will be described below in connection with such use, although other uses are contemplated, including the application of liquid medicaments.

Background

Certain diseases of the respiratory tract are known to correspond to treatment by direct application of therapeutic agents. Since these medicaments are mostly in the form of dry powders, they are most conveniently administered by inhaling such powdered materials through the nose or mouth. This powder form enables a better utilization of the drug, since the drug is deposited exactly where it is desired and where it is needed for its action; thus, a very small dose of a drug is generally equivalent to a larger dose that would otherwise be applied, with the result being a significant reduction in adverse side effect effects and drug costs. Alternatively, the powdered medicament may be used to treat diseases other than respiratory diseases. When a drug is deposited on a very large surface of the lungs, it can be absorbed into the bloodstream very rapidly; thus, such application methods may be used instead of application by injection, tablet or other conventional means.

It is a opinion of the pharmaceutical industry that the bioavailability of drugs is optimum when the drug particles delivered to the respiratory tract are between about 1 to 5 microns in size. When drug particles are required to be in this size range, dry powder delivery systems must address a number of issues:

(1) small sized particles can themselves develop electrostatic charges during manufacture and storage. This results in agglomeration or aggregation of the particles, thereby producing agglomerates of particles having an effective size greater than about 5 microns. The likelihood of such large masses entering the deep lung is reduced. This results in a reduction in the percentage of drug absorbed by the patient.

(2) The dose of active drug that must be delivered to a patient may be on the order of tens of micrograms. Since current powder filling equipment cannot effectively deliver a dose of medicament (aliquot) in the milligram dose range with acceptable accuracy, it is common practice to mix the active medicament with a filler or bulking agent such as lactose. Such additives also make the drug "flowable". In some cases, such fillers are sometimes also referred to as carriers. These carrier particles are larger in size than the drug particles. The ability of a dry powder inhaler to separate the drug from the carrier is an important performance parameter in terms of the effectiveness of the design.

(3) Particles of active drug greater than about 5 microns in size will be deposited in the mouth or throat. This introduces another uncertainty because the potency and absorption of the drug at these locations is usually different from that of the lung. Dry powder inhalers must minimize the drug deposited at these locations to reduce the uncertainty associated with the efficacy of the drug.

Prior art Dry Powder Inhalers (DPIs) typically have means for introducing the medicament (active plus carrier) into a high velocity air stream. The high velocity gas stream serves as the primary mechanism for breaking up the mass of micronized particles or separating the drug particles from the carrier. Several inhalation devices for dispensing such medicament in powder form are known in the art. For example, in us patent 3,507,277; 3,518,992, respectively; 3,635,219, respectively; 3,795,244, respectively; and 3,807,400, the disclosed inhalation device has means for piercing or removing the top of the capsule containing the powdered medicament which is drawn from the pierced or truncated capsule and into the mouth of the user upon inhalation. Several of these patents disclose impeller means which assist in dispensing powder from the capsule on inhalation, and therefore do not have to rely solely on the inhalation air flow to draw powder from the capsule. For example, in U.S. patent No.2,517,482, a device is disclosed having a powder-containing capsule placed in a lower chamber prior to inhalation, the capsule being pierced by a user manually depressing a piercing pin. After piercing, inhalation begins and the capsule is pulled into the upper chamber of the device where it moves in all directions to cause powder to be dispensed out through the pierced holes and into the inhalation airflow. U.S. patent No.3,831,606 discloses an inhalation device having a plurality of piercing pins, a pusher means, and a self-contained powder source for operating the pusher means by external manual manipulation, whereby the pusher means assists in the distribution of powder into the inhalation air stream upon inhalation. See also U.S. patent No.5,458,135.

These prior art devices present several problems and have several disadvantages. For example, these prior art devices require the user to exert considerable force upon inhalation to effect dispensing or withdrawal of the powder from the pierced capsule and into the inhalation air stream. In these prior art devices, aspiration of the powder through a puncture in the capsule by inhalation generally does not extract all or even most of the powder from the capsule, thus resulting in a waste of medicament. Also, such prior art devices may result in uncontrolled amounts or chunks of powder material being inhaled into the user's mouth, rather than a controlled amount of well dispersed powder being constantly inhaled.

The above description of the prior art is largely derived from U.S. patent No.3,948,264 to Wilke et al, which discloses an apparatus for facilitating inhalation of powdered medicaments that includes a body portion having primary and secondary inlet channels and an outlet channel. The secondary inlet channel provides an enclosure for a capsule containing powdered medicament and the outlet channel is formed as a mouthpiece projecting from the body. Also provided is a capsule piercing structure that, upon actuation, forms one or more apertures in the capsule such that upon vibration of the capsule by an electromechanical vibrator, powdered medicament can be released from the capsule. The lancing device disclosed in the Wilke et al patent includes three radially mounted, spring biased, lancet mounted in a cycloidal chamber. Upon rotation of the chamber by hand, the capsule is pierced by simultaneous inward radial movement of the needles. Further rotation of the chamber causes the needle to be retracted by its spring means to its initial position to withdraw the needle from the capsule. The electromechanical vibrator includes a vibrating plunger rod at its innermost end that extends into the intersection of the inlet and outlet passages. Connected to the plunger rod is a mechanical solenoid buzzer for energizing the rod to vibrate. The buzzer is powered by a high power battery and actuated by a push button switch. According to Wilke et al, when the electromechanical vibrator 10 is actuated by sucking in through the air outlet channel 3 and simultaneously depressing the switch 10d, the air flow sucking in through the air inlet channels 4 and 12 and passing through the secondary air inlet channel 4 raises the capsule against the vibrating plunger rod 10 a. The capsule is thus vibrated rapidly and the powder flows and is dispensed from the pierced holes therein. (this technique is commonly used in manufacturing for dispensing powder through a funnel, where the funnel is vibrated to cause the powder to flow and move through the funnel outlet. The air flow through the inlet channels 4 and 12 helps to draw the powder out of the capsule and carry it through the outlet channel 3 to the user's mouth. The Wilke et al patent also discloses that the electromechanical vibrator device may be arranged at right angles to the inlet chamber and that the amplitude and frequency of the vibrations may be varied to adjust the dispensing characteristics of the inhaler.

The prior art devices have a number of disadvantages which make them undesirable for delivering dry powders to the lungs. Some of these disadvantages are:

the performance of prior art inhalers depends on the flow rate produced by the user. Lower flow rates do not produce a completely deagglomerated powder and therefore have an adverse effect on the dose delivered to the patient.

Drug dosage is not consistent in efficacy due to lack of consistency in the depolymerization process.

Driving the electromechanical inhaler requires a lot of energy, which increases the size of the device, making it unsuitable for portable use.

Leakage of the drug from the open or truncated capsule.

The drug in the open or truncated capsule degrades due to exposure to oxygen or moisture.

In my prior U.S. Pat. Nos. 6,026,809 and 6,142,146 (common to Abrams), we have provided an inhaler that utilizes a vibrator to facilitate the introduction of a suspension of a medicament or substance into a gas, which overcomes the foregoing and other drawbacks and deficiencies of the prior art described above. More specifically, the inhaler of my aforementioned patent includes a piezoelectric vibrator for deaggregating the drug or medicine and driving the deaggregated drug or medicine into suspension. In one embodiment of the' 809 patent shown in fig. 3, the inhaler 10 includes a hard plastic or metal housing 18 that is generally L-shaped in longitudinal cross-section. The housing 18 includes four airflow openings 20, 28, 30, and 32. The inhaler 10 includes a primary air flow passageway 26, the passageway 26 extending along the length of the housing 18 from the front 22 (at the opening 20) to the rear 24 (at the opening 28) thereof and having a generally square transverse cross-section to allow air flow therethrough (identified by arrows F in figure 1).

The second air duct 31 is generally L-shaped and extends longitudinally from an opening 30 in the surface of the rear portion 24 of the housing 18 to the main passage 26. The one-way valve 50 is mounted to the inner surface of the main passage 26 by a conventional spring-biased hinge mechanism (not shown) adapted to cause the valve 50 to completely block the airflow S through the duct 31 to the main passage 26 when the pressure of the airflow F in the main passage 26 is below a predetermined threshold value indicative of inhalation by a user through the passage 26.

A powder dispensing chamber 51 is formed in the housing 18 for holding a capsule 34 containing the powdered medicament to be inhaled. The housing 18 comprises, at the rear portion 24, a movable plate portion 32 for allowing the capsule 34 to be introduced into the chamber 51 and arranged on the seat 52 of the vibrating element 36 between the guides 60A, 60B. Preferably, the element 36 comprises a hard plastic or metal protective shell 37 surrounding a piezoelectric vibrator (not shown). Preferably, the piezoelectric vibrator is mechanically coupled to the cartridge 34 such that maximum vibrational capability is transmitted from the vibrator to the cartridge 34. The guide means 60A, 60B comprise two surfaces inclined downwards towards the seat 52 to facilitate the introduction and retention of the capsule on the seat 52 in the chamber 51. The removable plate 32 comprises a further air inlet 34 for allowing a further air flow S2 from the chamber 51 to enter the duct 31 through the duct 61 during inhalation by the user. Preferably, the plate 32 and the housing 18 include conventional mating mounting means (not shown) for allowing a user to removably re-secure the plate 32 to the housing between introducing a new (i.e. fully filled) capsule and removing a used (i.e. empty) capsule.

The piezoelectric element is made of a material having a high frequency and preferably an ultrasonic resonance frequency (e.g., about 15 to 50kHz), and vibrates at a specific frequency and amplitude according to the frequency and/or amplitude of excitation electric energy applied to the piezoelectric element. Examples of materials that can be used to construct the piezoelectric element include quartz and polycrystalline ceramic materials (e.g., barium titanate and lead zirconate titanate). Advantageously, by vibrating the piezoelectric element at ultrasonic frequencies, noise associated with vibrating the piezoelectric element at lower (i.e., non-ultrasonic) frequencies can be avoided.

In operation, the package 34 containing the medicament is pierced and inserted into the cavity 51 on the surface 52 of the vibrator 36 in the manner previously described. The power switch is placed in the "ON" position and the user inhales air through the duct 26, and an airflow F is generated through the duct 26. This deflects the one-way valve 50 to allow airflow S into the duct 26 through the opening 30, and also causes airflow S2 to enter the duct 26 through the opening 34 and the chamber 51. The ingestion of the air flow F is detected by the sensor 40 and a signal is sent to an actuation controller (not shown) which causes power to be supplied to a controller (not shown). The controller then adjusts the amplitude and frequency of the actuation power supplied to the piezoelectric element until they are optimized for maximum possible deagglomeration of the powder P and its passage from the capsule into the gas flow F by the gas flow S.

In a preferred embodiment of my aforementioned 809 'and 146' patents, the medicament or drug is supplied from a ribbon having a plurality of spaced blisters or slots for carrying controlled amounts of the dry powder medicament or drug.

Disclosure of Invention

The present invention provides a dry powder inhaler which employs synthetic jet (synthetic jet) technology to atomise a pharmaceutical powder from a blister pack or the like. Synthetic jets are not new. It has been found that at least as early as 1950, the use of a chamber having an orifice with an acoustic wave generating device incorporated at one end and a rigid wall incorporated at the other end, produces an air flow emanating from the orifice and out of the chamber when acoustic waves are emitted from the generator at a sufficiently high frequency and amplitude. See, for example, Ingard and laboratory, Acoustic Circulation Effects and nonlinear Impedance of Orifices, The Journal of The Acoustic Society of America, March 1950 (3 months of 1950). The jet, or so-called "synthetic jet", comprises a jet of a series of vortices formed at an orifice at the frequency of the generator. However, the use of synthetic jets to deagglomerate and eject dry powder material from blister packs and the like in dry powder inhalers is new and has advantages over prior art dry powder inhalers.

The present invention provides a dry powder inhaler comprising: a first chamber for holding a dry powder; a second chamber directly connected to the first chamber by a passageway for receiving the dry powder in aerosol form and communicating the aerosolized dry powder to a user; and a vibrator for atomizing the dry powder and driving the dry powder back and forth in the passageway from the first chamber to the second chamber, wherein the first chamber is in communication with only the second chamber and the atomized dry powder is introduced into the second chamber by the synthetic jet.

More specifically, the present invention provides a dry powder inhaler comprising: a first chamber for holding a dry powder; and a second chamber connected to the first chamber by a passageway for receiving the dry powder in aerosol form from the first chamber and communicating the aerosolized dry powder to a user. A vibrator is coupled to the dry powder in the first chamber. Since the jet efficiency decreases with the aspect ratio (length/cross-section or diameter) of the passageway, to form a synthetic jet, the passageway connecting the first chamber to the second chamber preferably, but not necessarily, has an aspect ratio equivalent to at least about 1, and the vibrator is energized and coupled to the first chamber to cause the gas to move back and forth in the passageway at a distance of at least about twice the passageway cross-section or diameter.

In one embodiment, the first chamber is formed as a cylinder or blister and the vibrating element forms one wall of the chamber, or the vibrating element is formed separately from the chamber and bonded to the blister.

In a second embodiment, the first chamber is formed in a horn shape and the vibrating element forms one wall of the chamber, or the vibrating element is coupled to one wall of the chamber by an air column.

In the third embodiment, the first chamber is formed in a horn shape, and one standing wave resonator is bonded to one wall of the chamber.

Drawings

Other features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of one embodiment of a prior art inhaler.

FIG. 2 is a diagram showing the relationship between a blister containing a medication and a synthetic jet of the present invention;

FIG. 3 is a schematic cross-sectional view of a chamber and a vibratory element according to a first embodiment of the invention;

FIG. 3a is an enlarged cross-sectional view of the element shown in FIG. 3;

FIG. 3b is a view similar to FIG. 3a of an alternative embodiment of a chamber component made in accordance with the present invention;

FIG. 4 is a schematic cross-sectional view of a chamber and a vibratory element according to a second embodiment of the invention;

FIG. 5 is a schematic cross-sectional view of a chamber and a vibratory element according to a third embodiment of the invention; and

fig. 6-9 are views similar to fig. 5 of other embodiments of the present invention.

Detailed Description

Referring to fig. 2, the inhaler 205 according to the present invention must comprise elements such as a vibrator (e.g. a piezoelectric element 204), a first chamber 203 and a second chamber 202 connected by a channel 201. The dimensions and shape of the passage 201 are designed such that the reciprocating or oscillating motion of a vibrator coupled to or constituting a wall of the first chamber causes the gas in the first chamber to move back and forth through the passage 201 so that a substantially equal amount of gas moves in each direction while forming a gas vortex at the outlet of the passage 201, thereby having a net flow of gas exiting from the outlet end of the passage 201, i.e. forming a synthetic jet of gas from the vortex. A vibrator 204, which is operatively connected to the first chamber, either directly or via a closed gas tube 206, creates vibrations in the chamber that form a synthetic jet at the outlet end of the channel 201. The dry powder 210 in the chamber floats, is at least partially deaggregated to a particle shape in the first chamber 203, and is suspended in the gas in the chamber to form an aerosol 212. The resulting aerosol is delivered to the passage 201 where at least a portion of the suspended dry powder particles pass through the passage 201 without returning to the first chamber, thereby communicating between the first chamber 203 and the second chamber 202. This process continues until most of the dry powder is expelled from the first chamber 203.

Although synthetic jets can be formed outside the limits of the following parameters and are thus not excluded from the scope of the invention, preferred parameters for forming the synthetic jets of the invention are as follows:

1. the aspect ratio of the channel, i.e. the ratio of the length of the channel to the cross-section or diameter, is preferably at least 0.5 and preferably greater than or equal to about 1. This aspect ratio helps to ensure that the gas moving back and forth in the channel is formed as a discontinuous well-formed gas plug.

2. The distance that the gas moves back and forth through the channel is preferably greater than about twice the cross-section or diameter of the channel. This ensures that the dry powder deagglomerated by the formed vortex has the opportunity to escape the vortex before the gas returns through the channel.

3. Turbulence associated with swirling and reciprocating gas within the chamber and channel is minimized to enhance the flow of the synthetic jet. Thus, the surfaces of the channel and the flange areas around the outlets at both ends of the channel 201 should preferably be free of burrs or other obstructions.

4. The channels have a cross-sectional diameter in the range of 0.001 'to 0.050'.

To ensure that the distance that the gas moves back and forth through the channel 201 is greater than twice the cross-section or diameter of the channel 201, there should be a minimum power density (or magnitude of pressure change) in the channel 201. The lowest power density can be produced simply by inducing a vibration of sufficient intensity in the first chamber 203. Preferably, the first chamber 203 may comprise a resonator, such as an elastomer or standing wave resonator, and/or a horn for concentrating energy near the channel and moving gas between the first and second chambers.

As will be described below, in a preferred embodiment of the invention, the first chamber 203 and the channel 201 comprise pre-formed blister packs containing dry powder medicaments or pharmaceutical products.

Referring to fig. 3 and 3a, a blister package 300 made in accordance with a preferred embodiment of the present invention is constructed of a three layer laminate material 305 comprising an outer oriented polyamide sheet 306, an intermediate layer 307 of aluminum foil, and an inner polyvinyl chloride sheet 308. The three-layer laminate 305 is about 0.005 "thick and is cold formed into a bowl-shaped base or bottom member 309 having a generally flat bottom 310 of about 0.194" diameter, an overall height of about 0.270 "and a widest point diameter of about 0.350". Alternatively, as shown in fig. 3b, the blister pack may be formed with a flat bottom 320. The bottom or base is partially filled with dry powder and the top 312, also formed of a three layer laminate, is heat sealed to the bottom. Four holes 320 of about 0.012 "diameter are formed in the top of the blister, spaced about 0.056" from the first chamber axis.

Bottom 310 of blister pack 300 is arranged to contact a Murata MA40E7S piezoelectric transducer 314(Murata Electronics North America, inc., Smyma, GA). The surface 316 of the transducer of about 0.006 "is removed to adjust the pressure to a resonant frequency of about 34 KHz. The transducer was driven at a frequency of 34KHz with a voltage of 150 Vpp. A standing wave resonator is formed within the blister. Jets of up to 200 feet/min were measured with a hot wire anemometer (VWR International catalog #21800-024) to allow good extraction and deaggregation of the dry powder from the blister.

Figure 4 shows a second embodiment of the invention in which an acoustic horn (acoustic horn) is used to move the chamber gas from the first chamber to the second chamber. In the second embodiment, the powder dispensing chamber comprises a cylindrical first chamber 400 made of a material such as polycarbonate. The vibrating element 408 is coupled to the proximal end of the first chamber 400 such that the magnitude of the pressure change communicated by the vibrating element 408 is toward the distal end 410 of the chamber 400. The resulting pressure change forms a synthetic jet that distributes powder from the first chamber 400 through the passage 412 into the second chamber 404.

Several experimental conical horn profiles were machined from polycarbonate to test the jet velocity formed by the horn-shaped first chamber. In a first example, as shown in FIG. 5, the bottom 502 of the horn 504 has a diameter of about 0.400 "and is coupled to the vibrating surface 506 of the Murata MA40E7S piezoelectric transducer 508, from which material is removed so that it has a resonant frequency of 30.4 KHz. The vibrating surface of the transducer thus forms the bottom wall of the first chamber. The length of the horn (i.e., from its bottom end 502 to its top end 510) is 0.204 ". The tip 510 of the horn is 0.1 "in diameter. A piece of 0.0125 "thick polycarbonate pad (shim stock) was adhered to the top of the horn. A 0.012 "diameter hole 514 is formed in the spacer so that it is generally aligned with the axis 516 of the horn. This configuration creates a standing wave resonance of about 30 KHz. The transducer was driven at a frequency of 29.8KHz at a voltage of 54Vpp and a corresponding jet velocity of 1030 ft/min was measured at orifice 514. At a higher voltage of 120Vpp, a jet velocity of 1640 feet/min was measured. In both cases, the jet velocity is higher than necessary to achieve better extraction and deagglomeration of the powder from the first chamber.

Referring to fig. 6, another conical horn profile is machined from aluminum. The bottom 602 of the horn has a diameter of about 0.400 "and is coupled to a vibrating surface 604 of a Murata MA40E7S piezoelectric transducer 606, from which material is removed so that it has a resonant frequency of 30.4 KHz. Between the vibrating surface 604 of the piezoelectric transducer and the horn a laminate film 608 is inserted, which comprises outer oriented polyurethane, aluminum and inner polyvinyl chloride and comprises an acoustic window. This three-layer laminate is about 0.001 "thick and about 0.01" from the vibrating surface of the piezoelectric transducer. The vibrations from the transducer are then acoustically coupled to the interior of the horn. The distance between the top surface of the membrane 606 and the bottom end of the horn 602 is 0.204 ". The tip of the horn 602 terminates in a wall 614 which is 0.010 "thick and in which four holes 610 are formed, each hole 610 having a diameter of 0.012" and being spaced 0.056 "from the axis 612 of the horn. This produces a standing wave resonance at 31.0 KHz. The transducer was driven at a frequency of 31.0KHz at a voltage of 54Vpp, which produced a jet velocity of 434 ft/min. As the drive voltage was increased to 120Vpp, the jet velocity increased to a jet velocity of 1381 ft/min. In both cases, the jet velocity is higher than necessary to achieve extraction and deagglomeration of the dry powder from the chamber.

In a third embodiment of the present invention, as shown in FIG. 7, the tapered first chamber 702 has a horn length (measured along its axis 704) of 0.204'. This configuration simultaneously gives the standing wave resonator a benefit of pressure amplification of the horn to further reduce the magnitude of pressure change required by the vibrator to form the synthetic jet. In this embodiment, the vibrator 706 is operatively coupled to the flexible wall 710 of the first chamber 702, i.e., as shown in FIG. 7. Alternatively, as shown in fig. 8, the vibrator 806 may be acoustically coupled to the first chamber 808, to the acoustic window 812, i.e. a region of the first chamber 802 that is sufficiently thin and flexible, through a gas tube 810, such that most of the vibrational energy will be transferred from one side of the region to the other. In this embodiment, it is advantageous to minimize the gap between the vibrator 806 and the acoustic window 812 so that the spring constant given by the medium in the gas tube 810 is of the same order of magnitude as the spring constant given by the acoustic window 812. Thus, the energy losses associated with the use of acoustic windows are minimized.

In a variation of the third embodiment, as shown in fig. 9, one wall 902 of the first chamber 904 may be formed by a vibrator, for example by making the wall from a polarized PVDF film or the like, and applying an alternating voltage across the PVDF film to cause the PVDF film to bend and generate pressure waves.

Although cylindrical and conical shapes are described above, the chamber may be of different shapes. In all cases, one wall of the chamber should be flat or nearly flat or at least have a generally flat or slightly rounded surface to interface or bond with the vibrating element.

In each of the above embodiments, the vibrating element may be a piezoelectric transducer, an electrodynamic (loudspeaker) transducer, or a magnetostrictive transducer, similar to those used in ultrasonic cleaning tanks, in addition to the mentioned vibrator. Reciprocating piston pumps may also be employed to generate gas pulses that induce synthetic jets. Any vibrator and linkage combination suitable for creating the vibrations needed to generate the synthetic jet is within the scope of the present invention.

Other configurations are possible and still be within the scope of the present invention. For example, it may be desirable to arrange an acoustic window in the chamber to couple energy from the transducer to the acoustic window of the chamber through a horn. This approach provides two acoustic impedance transformations, one (horn) increasing the acoustic pressure to match the impedance provided at the acoustic window, and the second (helmholtz resonator) matching the acoustic impedance of the air in the chamber.

Various other changes may be made in the foregoing without departing from the spirit and scope of the invention, and it will be apparent to those skilled in the art that such changes and modifications are intended to be covered herein.

Claims (12)

1. A dry powder inhaler comprising:

a first chamber for holding a dry powder;

a second chamber directly connected to the first chamber by a passageway for receiving the dry powder in aerosol form and communicating the aerosolized dry powder to a user; and

a vibrator for atomizing the dry powder and driving the dry powder back and forth in the passageway from the first chamber to the second chamber,

characterised in that the first chamber is in communication with the second chamber only and in that the atomised dry powder is introduced into the second chamber by means of a synthetic jet.

2. The dry powder inhaler of claim 1, wherein the passageway has a length to diameter ratio of at least 0.5.

3. The dry powder inhaler of claim 1, wherein the first compartment is a blister pack.

4. The dry powder inhaler of claim 1, wherein the first chamber is cylindrical, conical, or flared.

5. The dry powder inhaler of claim 1, wherein the first chamber comprises a standing wave resonator.

6. The dry powder inhaler of claim 5, wherein the standing wave resonator comprises a Helmholtz resonator.

7. The dry powder inhaler of claim 1, wherein the vibrator is a piezoelectric transducer.

8. The dry powder inhaler of claim 1, wherein the first chamber is constructed of plastic or metal.

9. The dry powder inhaler of claim 1, wherein the first chamber is constructed from a cold-formed laminate.

10. The dry powder inhaler of claim 9, wherein the laminate comprises a three layer laminate of oriented polyamide, aluminum foil, and polyvinyl chloride.

11. The dry powder inhaler of claim 1, wherein the passageway is circular and has a diameter, and the distance the gas travels back and forth is at least twice the diameter of the passageway.

12. A dry powder inhaler according to claim 1, wherein the dry powder is moved from the first chamber to the second chamber by means of a gas pulse created by the vibrator.