WO2008017575A1

WO2008017575A1 - An inhaler and a method of dispensing medication to a person

Info

Publication number: WO2008017575A1
Application number: PCT/EP2007/057365
Authority: WO
Inventors: Boris Nordstrøm VALENTIN
Original assignee: Bang & Olufsen Medicom A/S
Priority date: 2006-08-07
Filing date: 2007-07-17
Publication date: 2008-02-14

Abstract

Methods and apparatus for dispensing medication to be inhaled in the shape of an aerosol, where the dispensed aerosol is given a zig-zag-shaped path due to a number of air/gas flows directed partly against the direction of the flow in order to slow the aerosol down and prevent the aerosol from impacting in the inhaler.

Description

AN INHALER AND A METHOD OF DISPENSING MEDICATION TO A PERSON

The present invention relates to methods and apparatus for delivering a dose of an aerosol, which is a gas with entrained medication on droplet form or as a powder for inhalation by a patient.

Aerosols, or powder/droplet-shaped medication provided in other manners, are increasingly being used for delivering medication for therapeutic treatment of the lungs. For example, in the treatment of asthma, inhalers are commonly used for delivering bronchodilators such as P2 agonists and anti-inflammatory agents such as corticosteroids. Lately, the use of lung deposition of aerosols for systemic treatment of i.e. diabetes has become of interest. Two types of inhalers are in common use, metered dose inhalers (MDIs) and dry powder inhalers (DPIs). Both types have as their object the delivery of medication.

In the DPI device, the medication is typically in the form of a solid particulate or powder. A metered dose is available upon loading and the dose is disintegrated to small particles ether by means of turbulence in the flow path to the mouth of the patient, or the powder is aerosolized by air injection form a compressed air source, or active shakers like piezo transducers are used for disintegration to a particle size useful to pass the air tract of the patient and to be deposited into the lungs at the location of the condition being treated.

In the MDI device, the medication is provided by the pharmaceutical manufacturer in a pressurized aerosol canister, with the medication being suspended or dissolved in a liquid propellant such as a chlorofluorocarbon (CFC) or hydrofluoroalkane (HFA). The canister includes a metering valve having a hollow discharge stem which can be depressed inward into the canister to discharge a metered volume of propellant- medication mixture in the form of an aerosol comprising fine droplets of propellant in which particles of the medication are suspended or dissolved. A typical MDI for use with such a canister includes a housing having an actuator and nozzle. The canister is inserted into the housing with the hollow discharge stem of the canister being received in a bore in the actuator. Depressing the closed end of the canister causes the stem to be pushed inward into the canister so that a metered volume of medication is discharged through the nozzle.

The housing further defines a flow path in fluid communication with the nozzle, the flow path having an outlet at a mouthpiece portion of the housing, such that the aerosolized medication may be inhaled after it exits the mouthpiece portion. The patient either inserts the mouthpiece into the mouth with the lips closed around the mouthpiece, or holds the mouthpiece at a slight distance away from an open mouth. The patient then depresses the canister to discharge the medication, and simultaneously inhales. Existing MDIs suffer from a number of significant disadvantages. One problem with existing MDIs is poor delivery efficiency of the medication. It has been estimated that on average, with existing MDIs, only about 10 percent of the medication dose which is dispensed from the canister actually reaches the lungs where it can achieve the intended result.

Poor delivery efficiency is caused by a number of factors. One of these is incomplete evaporation of propellant, resulting in a large portion of the metered dose being delivered in a form which cannot be inhaled into the lungs. For effective delivery of aerosolized medication to the airways of the lungs, it is desirable that most of the particles which are inspired be less than about 10 μm in size, and preferably between about 1 μm and 5 μm. Incomplete evaporation of propellant at the outlet of the mouthpiece results in a substantial fraction of the metered dose being delivered in the form of relatively large liquid droplets instead of fine dry particles and/or vapour. Such droplets cannot be inspired, but rather tend to impact the inside of the mouth and at the back of the patient's throat, with the result that much of the medication is swallowed.

Another factor contributing to the problem of poor delivery efficiency is high linear velocity of the aerosol as it exits the mouthpiece, which tends to lead to impaction of the aerosol in the mouth and throat. Typically the aerosol leaves the nozzle with a velocity of 50-100m/s. Ideally, the velocity of the aerosol should match the velocity of the patient's inspired breath which typically is in the region of 0.5 to 2.0 m/s so that the particles are entrained in the breath and carried into the lungs. With many existing MDIs, the exit velocity of the aerosol substantially exceeds the velocity of the patient's breath. The high-velocity plume strikes the back of the throat, causing impaction and sticking.

Yet another factor contributing to the poor delivery efficiency of existing MDIs is excessive length of the plume or bolus of aerosol exiting the device. In existing MDIs, this length typically exceeds 25 centimetres, which makes it difficult for the patient to inhale the entire bolus. In an effort to decrease plume velocity, some MDI designers have added tubular spacers between the aerosol nozzle and the mouthpiece. Although spacers improve delivery efficiency, most of the drug which is discharged from the nozzle impacts and sticks on inner surfaces of the spacer, and is therefore unavailable for inhalation by the user. Thus, MDIs with spacers still suffer from unacceptably low delivery efficiencies.

Droplet-shaped medication may be obtained in other manners than by using a liquid propellant, such as by forcing the medication through one or more fine holes or nozzles. One manner of obtaining this is to provide the medication in metered form in a blister or collapsible bag and compress the blister/bag so as to force the medication through fine holes of a surface of the blister/bag. Due to the force required in order to obtain a sufficient droplet formation, the output velocity of this medication has the disadvantages described in relation to pressurized canisters.

Naturally, medication powder may also be dispensed by injecting the powder into a gas flow to form an inhalable aerosol.

Furthermore, although dry powder inhalers inherently avoid some of the aforementioned problems of MDIs, such as excessive aerosol velocity, DPIs still suffer from the problem of impaction and sticking of medication on the inner surfaces of the devices, particularly under certain environmental conditions such as high relative humidity, which tends to cause particle aggregation.

EP1627655 claims a breath actuated MDI inhaler (BAI) with a centrally placed tube that will eject air towards the nozzle orifice to slow down the plume velocity and furthermore introduces radially placed air inlets and vortex generators to increase the effective path of the aerosol in the mouthpiece, when the patient breathes through the mouthpiece. The solution offers the advantages of breath actuation and slowing down the plume velocity within the volume of a standard mouthpiece, but the extra parts in the mouthpiece are fragile and make it very difficult to clean excess medication that inevitably will be deposited inside the mouthpiece during use and poses hygienic risk to the patient.

WO2004/041338 and EP1010438 claim a MDI inhaler with an external cyclonic flow chamber to achieve a long effective flow path to slow down the plume velocity and allow evaporation of the propellant. The solution increases the volume of the inhaler to a size that is uncomfortable to carry in a pocket.

Other solutions may be seen in GB2279879, EP0839544 and EP0862921.

Accordingly, it is an object of the present invention to provide a method and apparatus for delivering powder/drop-shaped medication in which the respirable fraction of the metered dose (i.e., the fraction in the form of dry particles of the optimum size) is improved at the exit of the apparatus without sacrificing the size and the hygienic standard of the inhaler.

It is a further object of the present invention to provide a method and apparatus for delivering a powder/droplet-shaped (such as aerosolized) medication in which the linear velocity of the aerosol at the exit of the mouthpiece of the apparatus better matches the velocity of the patient's inspired breath and the length of the bolus of droplet-shaped (aerosolized) medication which exits the apparatus is as short as possible. A further object of the invention is to provide a method and apparatus for maximizing the evaporation of liquid propellant in an inhaler.

Still another object of the present invention is to provide an apparatus where flow restrictions in the flow path limits the flow velocity of the inhaled air/aerosol mixture to avoid collision with and deposition of aerosol particles on the rear side of the patient's throat.

A further object of the invention is to provide a design solution that is easy to manufacture to achieve a cost effective product design.

Still a further object of the invention is to provide an inhaler component that may be optimized and adapted for the aerosol dispensing of a specific drug. Such a component will be useful in customizing a proven inhaler design to several specific drugs.

The above and other objects of the invention are achieved by the methods and apparatus of the invention in which flow control techniques and devices are used to promote mixing of the aerosolized medication mixture with air, to slow down the aerosol plume before it reaches the exit of the apparatus, and to reduce the impaction of aerosol on the inner walls of the apparatus.

In a first aspect, the invention relates to an inhaler comprising:

a housing comprising wall parts defining a flow channel having an outlet,

a medication dispensing unit adapted to dispense medication as an aerosol with a velocity of 20 m/s or more into the flow channel, the aerosol having a general, predetermined direction toward the outlet,

at least two openings/channels in/through the wall parts, the openings/channels being directed in a direction having a component being opposite to the predetermined direction and a component being along a direction toward a centre axis of the flow channel, the openings being positioned at different radial positions and different axial positions around/along the predetermined direction.

In this connection, it is clear that the wall parts may be formed as a channel or tunnel into which the medication is provided and into which the openings/channels are formed. However, even though it is desired to control the flow characteristics during providing of the medication as much as possible, it is not required to have the flow path fully surrounded by wall parts and the flow channel fully enclosed (along its length) by wall parts.

Naturally, the flow channel may have any cross sectional shape and it need not have the same cross sectional shape along its entire length. However, the flow channel will have a centre axis which normally will be defined as a straight line from a point of dispensing of the medication and a centre of the output, which normally is a tubular element through which the user inhales the medication.

Also, it is clear that the function of the openings/channels is to direct air/gas toward the flow of the aerosol, whereby the interesting parameters of these openings/channels are those close to the outlets thereof; the parts defining the flow of air/gas flowing through the openings/channels. Thus, the direction of the channel/opening is that which air/gas exiting the opening/channel would have.

In this connection, it is understood, that when a flow has a component in a given direction, this component may have any non-zero size. Thus, the flow may have an angle lower than 90 degrees, such as in the interval of 10-80 degrees, or even more preferably in the interval of 15-75 degrees with the direction.

A preferred embodiment is one wherein the channels/openings are provided by bores extending through the wall parts. The direction of these bores will define the direction of the channel/opening.

A medication dispensing unit may be any type of unit adapted to provide or dispense medication as an aerosol. In this connection, an aerosol is droplets or powder entrained in a flow of gas. Such units may be a pressurized canister, a pressure less liquid container, or even a powder container like a capsule, bag or blister that is emptied and aerosolized by a source of compressed air/gas, whenever the aeroionisation process is characterized by generating a high speed aerosol jet from an ejection orifice. One aerosol may be generated by a liquid propellant or by a separate source of gas.

Alternatively, the dispensing unit may hold the medication in a container, such as a blister, which is emptied, such as compressed, through one or more valves or holes, whereby the medication is output on the form of droplets or powder particles.

In this connection, droplets or powder is preferably of a size of 2-10 μm, such 3-6 μm which are useful for inhalation by a person. As the skilled person would know, too large droplets/particles will have an increased probability of impacting on the throat of the person and thereby remain useless, and too small droplets/particles may be exhaled again by the user instead of being collected in the lungs as intended.

The size of the droplets provided will depend on a number of factors of the providing technique, but in common to these are that the medication is forces through a valve or one or more small hole(s) in order to provide sufficiently small droplets. This, however, generates the overall problem of the velocity of the droplets. An aerosol with powder/droplets from a pressurized canister is output with a velocity of about 50 m/s, whereas a person inhaling normally inhales with a velocity of 2 m/s.

The velocity, in this situation, is the velocity of the droplets/powder at the position of providing (output from the canister or a valve, hole or the like generating the droplets).

The ejection of a medication dose may be controlled either manually by the patient or by a pressure sensitive valve activated by vacuum in the mouthpiece of the device generated from the inhalation manoeuvre from the patient. The latter solution enables optimized ejection timing within the inhalation period.

Naturally, when generating droplets by forcing these through openings or when generating droplets/powder of an aerosol, where a boiling liquid is used for separating the dose of medication into droplets/particles, the droplets/powder will be output not in a single direction but as a spray. The general direction of this spray is the mean direction of the majority of the droplets/powder and normally is defined as an axis of symmetry of the valve/hole(s) generating the spray.

The fact that the directions of the openings/channels have a component opposite to the direction of the flow of medication will provide a slowing down of the flow, which renders it more useful for inhalation, as the flow velocity will closer match that of inhaled air. Slowing down the plume also increases the residence time of the medication within the apparatus and leads to a shorter bolus to be inhaled. The increased mixing and residence time promotes more complete evaporation of a potential propellant or dissolvent at the exit of the mouthpiece.

In addition, the positioning of the openings/channels will cause changes of the direction of the flow in the flow channel, as the openings/channels have a direction with a component toward the centre axis (away from the wall part defining the opening/channel). Thus, when at least some of the openings/channels are positioned at different radial and axial positions, these will provide different changes of direction to the flow in addition to slowing it down. This overall effect may be used to provide a wide variety of flow scenarios in the flow channel.

In this connection, the axial direction of the flow is along the centre axis from the dispensing unit to the output, and the radial direction is at different radial directions around the centre axis, independent of the shape of the wall parts defining the flow channel.

In one embodiment, at least two of the openings/channels are positioned in a plane comprising the centre axis, the openings/channels of this plane being positioned intermittently, along the axial direction, on either side of the centre axis. In this connection, the openings/channels may be positioned so as to redirect aerosol flow, directed toward a wall part of the flow channel, back toward the centre axis. In addition, as the direction of the opening/channel is directed partly against the direction of the flow, this redirection automatically also is a slowing down of the aerosol.

In fact, it may be desired to have the openings/channels positioned so as to impart, on the aerosol and in a plane comprising the dispensing unit and the outlet, a sine-shaped or zig- zag-shaped flow from the dispensing unit to the outlet. Each turn or bend of this shape is generated by air/gas flow from an opening/channel, whereby each turn/bend is a slowing down of the flow.

Naturally and in general, the size and directions of the openings/channels may be varied or selected to determine the air/gas flow there through in order to ensure the desired redirection of the aerosol. It is desired that none or at least as few as possible of the droplets/particles impact on the wall parts, in that this makes the determination of the inhaled dose uncertain.

In another situation, the openings/channels are positioned along a spiral-shaped pattern. Thus, the aerosol flow may be given the same spiral-shaped pattern which, when projected onto a plane, may be seen as a zig-zag-pattern but which is a three-dimensional shape. Again, the positions and size (or more accurately: the flow characteristics of the air/gas provided thereby) of the openings/channels is selected to give a particular type of flow pattern where the flow is directed toward wall parts where openings/channels are, which provide a flow which slows the flow down and redirects the flow away from the wall part.

Yet another situation is one, wherein each of at least two of the openings/channels at least substantially circumscribes the flow path. In this situation, the air/gas flow will affect the aerosol flow from at least substantially all sides (all angles of the periphery), whereby the result is not a general redirecting of the flow in a given direction but that of redirecting the outer parts of the flow toward the center axis (while still slowing the flow), which provides a flow with a number of narrowings (waists). Thus, the droplets will again have zig-zag-shaped flow patterns, but different droplets/particles of the aerosol may have different flow patterns and in different planes (around the center axis).

A number of parameters define the characteristics of the gas flow provided by an opening/channel. Especially in the simple situation where an opening/channel is merely a bore in a wall part, the dimensions thereof will define how well-defined the direction of the air/gas flow is. Thus, in order to obtain a sufficiently well-defined flow, it is desired that the length of the opening/channel is at least 2 times a smallest dimension of a cross-section of the opening/channel, such as at least 3, 4, 5, 6, 7, or more times the smallest dimension of the cross-section. Channels/openings may be circular (where the dimension then is the diameter) and oblong (such as oval where the dimension then is twice the semi-minor axis). Oblong openings/channels have the advantage that they are able to better direct the aerosol. Naturally, the oblong channels may have any shape and cross-section.

In this connection, the flow generated by an opening/channel will depend on both the cross sectional area thereof as well as the gas velocity thereof. Presently, it is preferred that a cross-sectional area of a channel/an opening is ¹Z. mm² or more, such as between 1 and 10 mm², preferably in the interval of 2-5 mm².

In addition, the velocity of air/gas in the openings/channels during inhalation preferably is in the interval of 2-100 m/s, such as between 15 and 50 m/s, preferably in the interval of 20-30 m/s.

Naturally, the air/gas flow provided through the openings/channels may be provided in a number of manners, one being one wherein the inhaler further has means for connecting the openings/channels to the surroundings. In that situation, the gas/air flow will be generated automatically when the person inhales. This inhalation will provide a vacuum in the flow channel and thereby suck gas/air through the openings/channels from the surroundings.

In another embodiment, the inhaler has a source of pressurized air/gas and means for directing air/gas from the source to the openings/channels. Thus, a higher gas/air flow/velocity/volume may be available as may a more well-defined and reproducible aerosol flow. In addition, this source of pressurized air/gas may be used in the above-mentioned dispensing unit requiring a source of pressurized air/gas for forcing the medication through the valve/holes in order to obtain or separate the droplets/particles. In the most preferred embodiment, thus, an inhaler apparatus is obtained including a housing adapted to support a drug reservoir, the housing having an actuator and ejector assembly, the housing further including a generally tubular flow channel having an open end forming a mouthpiece adapted to be inserted into the mouth of a user, a drug ejection orifice positioned to direct a plume of aerosolized medication into the flow channel; the flow channel providing a plurality of air inlets directed backwards towards the inhalation flow and the ejection orifice plume direction.

Another aspect of the invention relates to a method of operating the above inhaler, the method comprising:

- operating the dispensing unit to dispense the aerosol,

simultaneously providing a flow of gas/air through the openings/channels and into the flow path.

Consequently, the providing of the aerosol is performed during providing of the flow of air/gas, in order to have the slowing down and redirections taking place.

As mentioned above, the method may further comprise the step of the person inhaling the mix of air/gas and droplets/powder. Then, the step of providing the flow could comprise the generation of the flow by the user inhaling the mix.

Alternatively, the providing of the air/gas flow may comprise providing such air/gas from another source of air/gas, such as a source of pressurized air/gas.

A final aspect of the invention relates to a method of dispensing medication to a person, the method comprising:

having the person engage, with his/her lips/mouth, a mouth piece of an inhaler,

providing, in a flow path of the inhaler, the medication as an aerosol at a providing position and with a general, predetermined direction from the providing position to the mouth piece,

providing, simultaneously to the providing of the aerosol, at least two air/gas flows inside the flow path, the gas flows having a component opposite to the predetermined direction and a component toward a center axis of the flow path and being provided at different radial and axial positions along/around the predetermined direction so that the aerosol, in at least one plane comprising the providing position and the outlet, obtains a sine- shaped or zig-zag-shaped path.

As mentioned above, the dispensing position may be defined by one or more valves or openings through which the medication is forced and the droplets generated or the powder particles separated, and the general direction thereof, even though the resulting aerosol will be provided as one or more jets, will be determinable, such as if defined by an axis of symmetry of the valve(s)/opening(s).

The air/gas flows may be generated in one of a wide variety of manners, such as the providing of valves, holes or openings/channels through which gas may be forced.

Again, the zig-zag-shaped path will provide the redirection and slowing down described further above.

In one embodiment, at least two of the flows are provided, in the plane, intermittently, along the axial direction, on either side of the centre axis, in order to generate a zig-zag-shaped path in that plane.

In another embodiment, the openings/channels are positioned so as to impart, on the aerosol a spiral-shaped flow along the flow path. This may be obtained by having the flows provided from positions along a spiral-shaped curve around the flow path.

Yet another embodiment is one, wherein each of at least two of the flows is provided from at least substantially a full circumference of the flow path. This may generate a flow with increasing and narrowing cross section.

Naturally, the flows may have different characteristics. This may be due to the aerosol velocity decreasing along the length of the flow path, and as the cross section of the aerosol may increase. Thus, different air/gas flow velocity, may be different, as may be area of the opening outputting the gas/air, or as may the angular extension of the opening in order to ensure that no droplets/particles (or as few as possible) will not be redirected and consequently impact in the inhaler.

In one embodiment, the step of providing the flows comprises forcing air/gas through two or more channels/openings having a length at least twice the smallest dimension of a cross section thereof. In one embodiment, the step of providing the flows comprises providing the flows with air from the surroundings, so that the air/gas flows may be generated by the inhalation itself.

In another embodiment, the step of providing the flows comprises providing the flows with air/gas from a source of pressurized air/gas.

Also, the step of providing the medication could comprise providing the medication from a pressurized canister adapted to provide aerosolized mediation.

In another embodiment, the step of providing the medication comprises providing a container containing the medication and forcing the medication out of the container in the shape of a plurality of droplets. Then, the step of forcing the medication out comprises providing pressurized gas/air from the source to the container to force the medication out of the container in the shape of the plurality of droplets.

In the following, preferred embodiments will be described with reference to the drawing, wherein:

Figure 1 illustrates a preferred embodiment of an inhaler with a special flow channel,

Figure 2 illustrates a flow channel with equally sized air inlets,

Figure 3 illustrates flow simulation results from the flow channel geometry shown in Figure 2,

Figure 4 illustrates a flow channel with differently sized air inlets, and

Figure 5 illustrates flow simulation results from the flow channel geometry shown in Figure 4.

Figure 1 shows one embodiment of an inhaler housing 101, having a support and nozzle 102 in this case for a pressurized canister.

A flow channel 103 constitutes a fluid connection between the nozzle 102 and the mouthpiece 106.The flow channel is furthermore providing a plurality of air inlets 104, which are fluidly connected to the inside of the inhaler housing. Apart from the aerosol jet 105 released from the nozzle 102, when the canister is activated, the only access of air into the flow channel 103 will enter through the air inlets 104. The arrows show the air flow path through the inhaler housing when a patient applies under-pressure to the mouthpiece 106. From openings in the inhaler housing 101 the air is driven through the inside structure of the housing to the space between the flow channel 103 and the mouthpiece 106 and finally through the flow channel air inlets 104. The direction of the air inlet holes is pointing slightly against the direction of the aerosol plume 105 and thereby introduces turbulent sub-volumes that will interact with the aerosol plume.

Therefore, the effective aerosol particle flow path will increase considerably and the particle velocity will decrease considerably without increasing the outside geometry of the inhaler. By careful design of geometry, relative position and inlet areas of the inlet holes 104 the flow channel 103 may be optimized to maximum performance with any source of medication and aerosol generator. Therefore, a well proven inhaler design may be improved and optimized by only exchanging the flow channel 103.

Furthermore, the specific flow resistance through the inhaler may be adjusted by the effective air inlet hole area to limit the inhalation flow to further limit the degree of medication deposition on the rear wall of the throat.

It is clear to those skilled in the art that a pressure sensitive arrangement may be placed within the air path in the inhaler, the purpose of which is to release a dose from the canister, when the patient begins to inhale at the mouthpiece 106. Such an arrangement may be mechanical i.e. such as disclosed in prior art US3456644 or US3814297 or may be electronic, such as disclosed in US3661528, and will improve the available fraction of medication to the patient.

The inside walls of the flow channel are smooth and the flow channel is therefore easy to clean if necessary.

Figure 2 shows one embodiment of the flow channel 103. The flow channel has four air inlets 104 and an aerosol inlet opening 201 to be fitted to the inhaler nozzle. The air inlets are designed as equally sized slits, the direction of the slits pointing at an angle of 120° relative to the main flow direction within the flow channel. The holes are positioned consecutively opposite to each other. The purpose of this geometry is to impinge on the aerosol jet to force the aerosol particles move in a slalom path and thereby reduce velocity and increase effective aerosol particle path length.

Figure 3 shows an example of a flow simulation of the geometry shown in Figure 2. Air flows in from the air inlet 104 and an aerosol particle jet 301 (black spots) is applied to the opening 201 in the flow channel. It can be seen that the particles are deflected and the effective particle flow path is increased. Simulations have shown that a reduction of aerosol particle velocity at the inhaler mouthpiece can be decreased by 50% with this geometry without increased particle deposition on the flow channel walls.

Figure 4 shows another embodiment of a flow channel design, where the air inlet holes are of different geometry, the direction of the slits still pointing at an angle of 120° relative to the main flow direction within the flow channel. The holes are still positioned consecutively opposite to each other.

Figure 5 shows an example of a flow simulation of the geometry shown in Figure 4. As it can be seen, the aerosol particle flow path is heavily disturbed by the jets from the air inlets resulting in further average aerosol particle velocity reduction and effective mixing of the aerosol particles into the air stream.

The flow simulations are merely included to demonstrate the variety of aerosol flow geometries achievable with the invention disclosed in this document. It should be emphasized that the air inlet holes may be placed randomly with various direction angles to the flow channel, the examples shown in this document is only for reference.

Naturally, a wide variety of designs may be implemented to take advantage of the overall strategy of extending the flow path and directing the flow toward a side portion in which a gas inlet is positioned (and directed toward/against the gas flow), so that the gas will change direction and at the same time be slowed down.

Thus, the illustrated 2-dimensional slalom path of figure 3 may be altered to be a 3D slalom path, such as in the shape of a torsion spring, where gas inlets are positioned so as to redirect the gas flow along the torsion spring path and simultaneously slow it down.

Other types of paths are possible, such as where a gas inlet is circular and positioned at a given position (or multiple such gas inlets are positioned at different distances from the inlet opening 201) so as to affect the gas flow from all sides, such as to make the gas flow widen thereafter. Naturally, such a gas inlet may be replaced by a number of gas inlets positioned circumferentially and at the same position. Providing multiple gas inlets at different distances from the inlet opening will make the gas cross section contract and widen at intervals, whereby the same effect is seen: the gas is directed (widening) toward the sides, where gas inlets are provided for slowing the gas and re-direct it again (narrowing).

It is clear that instead of providing the aerosol by a pressurized canister, this medication/gas mixture may be provided by forcing the medication through a nozzle or one or more openings, whereby droplets of the medication will be provided, or particles of a powder separated. Naturally, the droplet formation will depend on the velocity of the medication through the nozzle/opening(s) and the force required, whereby also this medication will be output at high velocities.

One manner of obtaining this type of droplet formation is the providing of the medication in a blister package or a collapsible bag having a covering foil with small holes therein.

Compressing the blister will force the medication out of the holes and to form droplets. Thus, one or more jets are formed of high velocity droplets that should be slowed down before inhalation.

Powder aerosols may be provided by entraining the powder in a high velocity gas flow in order to separate the particles.

Thus, medication delivered in this manner may equally well be delivered and slowed by the present invention.

Claims

1. An inhaler comprising:

a housing comprising wall parts defining a flow channel having an outlet,

2. An inhaler according to claim 1, wherein at least two of the openings/channels are positioned in a plane comprising the centre axis, the openings/channels of this plane being positioned intermittently, along the axial direction, on either side of the centre axis.

3. An inhaler according to claim 1, wherein the openings/channels are positioned so as to impart, on the aerosol and in a plane comprising the dispensing unit and the outlet, a sine- shaped or zig-zag-shaped flow from the dispensing unit to the outlet.

4. An inhaler according to claim I₇ wherein the openings/channels are positioned along a spiral-shaped pattern.

5. An inhaler according to claim 1, wherein each of at least two of the openings/channels at least substantially circumscribes the flow path.

6. An inhaler according to any of claims 1-4, wherein the openings/channels have different cross sections.

7. An inhaler according to any of the preceding claims, wherein the channels/openings have a length which is at least 2 times a smallest dimension in a cross section thereof.

8. An inhaler according to any of the preceding claims, further comprising means for connecting the openings/channels to the surroundings.

9. An inhaler according to any of claims 1-7, further comprising a source of pressurized air/gas and means for directing air/gas from the source to the openings/channels.

10. An inhaler according to any of the preceding claims, wherein the medication dispensing unit comprises a pressurized canister adapted to provide the aerosol.

11. An inhaler according to any of claims 1-9, wherein the medication dispensing unit comprises means for receiving a container containing the medication and means for forcing the medication out of the container in the form of an aerosol.

12. An inhaler according to claims 9 and 11, wherein the forcing means comprise means for having pressurized air/gas from the source force the medication out of the container in the form of the aerosol.

13. A method of operating the inhaler of claim 1, the method comprising:

operating the dispensing unit to dispense the aerosol,

14. A method according to claim 13, further comprising the step of the person inhaling the mix of air/gas and aerosol.

15. A method according to claim 13 or 14, wherein the step of providing the flow comprises the generation of the flow by the user inhaling the mix.

16. A method of dispensing medication to a person, the method comprising:

- having the person engage, with his/her lips/mouth, a mouth piece of an inhaler,

providing, in a flow path of the inhaler, the aerosol at a providing position and with a general, predetermined direction from the providing position to the mouth piece,

17. A method according to claim 16, wherein at least two of the flows are provided, in the plane, intermittently, along the axial direction, on either side of the centre axis.

18. A method according to claim 16, wherein the openings/channels are positioned so as to impart, on the aerosol, a spiral-shaped flow along the flow path.

19. A method according to claim 18, wherein the flows are provided from positions along a spiral-shaped curve around the flow path.

20. A method according to claim 16, wherein each of at least two of the flows are provided from at least substantially a full circumference of the flow path.

21. A method according to any of claims 16-20, wherein the flows have different characteristics.

22. A method according to any of claims 16-21, wherein the step of providing the flows comprises forcing air/gas through two or more channels/openings having a length of at least 2 times a smallest dimension of a cross section thereof.

23. A method according to any of claims 16-22, wherein the step of providing the flows comprises providing the flows with air from the surroundings.

24. A method according to any of claims 16-22, wherein the step of providing the flows comprises providing the flows with air/gas from a source of pressurized air/gas.

25. A method according to any of claims 16-24, wherein the step of providing the aerosol comprises providing the medication from a pressurized canister adapted to provide aerosolized mediation.

26. A method according to any of claims 16-25, wherein the step of providing the aerosol comprises providing a container containing the medication and forcing the medication out of the container in the form of an aerosol.

27. A method according to claim 26 and 24, wherein the step of forcing the medication out comprises providing pressurized gas/air from the source to the container to force the medication out of the container in the form of the aerosol.