GB2354451A - Inhalers - Google Patents

Abstract

A powder inhaler comprises a means 14 for dispensing powder into an air conduit with a deflecting device 1 mounted therein, wherein the deflecting device includes one or more rotatably mounted deflecting elements 4. The deflecting device may be located towards the nozzle outlet of the inhaler, preferably being in a detachable nozzle. The deflecting device may be driven by a drive device 8 that is driven by inhaling or by a battery driven motor. Alternatively the inhaler may comprise rotatable helical vanes (Fig 6) of variable pitch or deflecting elements whose paths of rotation sweep a part only of the cross-section of the air conduit (Fig 4). The deflecting elements may also be propellers or turbines (Fig 5), and have low friction surfaces. Alternatively the deflecting devices can be used in pressurized metered dose inhalers or nebulizing devices.

Description

2354451 Improvements in or relating to Inhaler Devices This invention

relates generally to powder inhalers and more particularly to nozzle devices and other parts for 5 use with such inhalers.

It has long been recognised that the nature of the air flow through an inhaler can affect the efficiency with which powder is delivered to a person's lungs upon inhalation. Powders prepared for use in inhalers are ideally formed of particles of a relatively large size so that they are easy to handle, for example, in terms of their readiness to flow. At the same time, however, in order that the powder can be delivered upon inhalation to a person's lungs, it is important that the size of the particles is small. Consequently it is advantageous if, during the process of inhalation, particles are broken up as they are delivered from the inhaler.

Various approaches to the design of an inhaler have been proposed in the past for the purpose of breaking up powder particles as they are delivered from the inhaler. For example, US Patent No. 4,524,769 describes the provision of a rotating means in the form of a propeller. US Patent No. 4,907,583 describes the use of stationary deflector devices in any of various parts of the inhaler, including a nozzle unit of the inhaler.

Whilst the use of a rotating element has certain advantages, we have found that the propeller arrangement proposed in US 4,524,769 is not very effective in breaking up particles.

It is an object of the invention to provide a powder inhaler including a moving element that is capable of improving the breaking up of particles of powder when powder is delivered from the inhaler.

According to a first aspect of the invention, there is provided a powder inhaler including means for receiving a powder to be dispensed, means for dispensing into an air conduit powder to be inhaled, the air conduit extending from one or more air inlets to a nozzle outlet, and a deflecting device mounted in the air conduit, wherein the deflecting device includes one or more rotatably mounted deflecting elements for altering substantially the flow of air through the conduit.

We have found that if a rotatable element such as an ordinary propeller is freely mounted in the air conduit, it actually has surprisingly little effect on the air flow:

during inhalation, air travelling through the air conduit rotates the propeller and, if the propeller is freely mounted as would be the obvious arrangement, the air continues to flow generally axially through the propeller; thus the flow of air through the conduit is not substantially altered. In contrast the present invention provides an arrangement in which the flow of air is substantially altered.

Although it is within the scope of the invention to provide the deflecting device upstream of the region at which powder is dispensed into the air conduit so as to alter the air flow prior to dispensing of the powder into the air flow, it is preferable that the deflecting device is provided downstream of the region at which powder is dispensed into the air conduit. In that case the alteration of the air flow takes place when the powder is entrained in the air f low so that the ef f ect on the powder is enhanced.

Preferably the deflecting device is provided towards that end of the air conduit which defines the nozzle outlet. Preferably at least one of the one or more deflecting elements is provided adjacent to the nozzle outlet.

The inhaler may have a detachable nozzle unit and the deflecting device is preferably provided in the nozzle unit.

Whilst a said rotatably mounted deflecting element may alter the flow of air in a variety of ways, it is preferred that at least one of the effects of the element or elements is to impart a rotational motion to the flow of air. A rotational motion is especially advantageous for breaking up particles of powder.

The or each rotatably mounted deflecting element may be moved by a separate source of power such as a motor but it is preferred that at least one rotatably mounted deflecting element is arranged such that it moves as a result of a f low of air generated by a person inhaling through the inhaler.

At least one said rotatable deflecting element is preferably arranged to be rotated at a speed relative to the air flow that prevents purely laminar axial air f low through the conduit past the deflecting element. Thus, for example, in the case of a simple rotatable deflecting element such as a helical element, there is a "natural,, rate of rotation of the element at which the rate of rotation (in revolutions per unit time) multiplied by the pitch of the helical element (measured in the axial displacement of the element over 3600) matches the axial flow speed of the air past the element; in that case the air flow through the deflecting element can be substantially axial and substantially laminar; thus it is preferred that the rotatable deflecting element is rotated at a speed away from that natural speed.

The inhaler is preferably arranged such that in the event that the rotatable deflecting element were to rotate at a speed that allowed essentially purely laminar axial air flow through the conduit, the element would be subjected to a substantial force causing it to accelerate or decelerate. In that case, the rotatable deflecting element should not rotate at a speed allowing axial air flow, except perhaps when accelerating or decelerating at the beginning or end of inhalation.

Advantageously, the deflecting device comprises first and second rotatably mounted deflecting elements.

The rotatably mounted deflecting elements preferably include a first element in the air conduit having a first natural rate of rotation for a given rate of inhalation through the nozzle outlet, the element being connected to a second movably mounted deflecting element driven by air f low generated upon inhalation through the nozzle outlet, that second element having a second natural rate of driving the first element for the given rate of inhalation through the nozzle outlet, the f irst and second natural rates being substantially different. By providing a second element which for the given rate of inhalation rotates the first element at a different rate from that at which it would naturally rotate for that rate of inhalation, it can be ensured that the first element has a substantial effect on the air flow through the conduit. There are of course other ways of achieving the same effect, such as mounting the rotatable deflecting element in a relatively high friction bearing; a disadvantage of an approach of that kind, however, is that some of the work involved in inhalation is expended simply in overcoming the friction. Nonetheless such arrangements are within the scope of the invention.

The first and second natural rates of rotation referred to above may differ in their magnitude and/or in their direction. For example, a first possible arrangement is for deflecting elements of opposite pitch to be mounted on the same rotatable shaft; those elements may have the same or different magnitudes of pitch. A second possible arrangement is for deflecting elements of differing pitch, the pitches being of the same sense, to be mounted on the same rotatable shaft. A third possibility is for the deflecting elements to comprise a generally helical element whose pitch varies along the axis of the shaft; the variation in pitch may be continuous along the axis of the shaft and may vary only in magnitude or also in direction.

As well as, or instead of, mounting deflecting elements on the same shaft, the deflecting device mounted in the air conduit may be driven via gearing, or some other coupling, by a drive device that may in turn be driven by an air stream generated upon inhalation.

Generally it will be desirable that at least one of the deflecting elements moves through a path extending substantially entirely across the cross-section of the air conduit and preferably at least one of the deflecting elements extends across substantially all of the crosssectional area of the air conduit. It will be understood that it is possible for a deflecting element to extend across substantially all of the cross-sectional area of the air conduit without blocking the air conduit because, for example, the element may be of helical form.

It is also possible, to provide deflecting elements that extend across a part only of the cross-sectional area of the air conduit and still to influence air flow across the entire cross-section of the conduit. Examples of the invention of this kind are described below with reference to the drawings.

In some cases it may be advantageous to provide a plurality of rotatably mounted deflecting elements side-byside in the air conduit.

At least one of the rotatably mounted deflecting elements may comprise a turbine blade.

Preferably at least one of the rotatably mounted deflecting elements is provided with a low-friction surface. The low-friction surface can be provided either by suitable selection of the material from which the element is made, or by providing a low-friction coating on the exterior of the element.

Where reference is made above to "at least one of the deflecting elements" it will be understood that in many cases it will be preferred that all of the deflecting elements have the characteristic described for the "at least one" deflecting element. Also it should be understood that although reference is made to a plurality of deflecting elements, that plurality of elements may comprise a single member. For example, the plurality of deflecting elements may be provided by a single helical member of varying pitch extending around a central axis.

Where reference is made to mounting the deflecting elements on a -shaft", it will be understood that the shaft need not be a rod or the like disposed along the axis of rotation but may alternatively be a cylindrical member extending around the axis of rotation. The deflecting elements may extend inwardly or outwardly or both inwardly and outwardly from such a cylindrical member; furthermore, the shaft may be present only at opposite ends of the deflecting device.

There may be a plurality of deflecting devices provided: for example there may be two devices arranged in the air conduit, one upstream and one downstream of the region where powder is dispensed into the conduit; the devices may share a common rotatable shaft; another possibility is for one of the devices to be provided in a separate air flow path which feeds into the air conduit at or upstream of the nozzle outlet.

According to a second aspect of the invention, there is provided a powder inhaler including a deflecting device mounted in an air conduit of the inhaler, the deflecting device comprising one or more generally helical vanes extending in combination around more than 2 complete turns, the helical vanes being mounted for rotation about their axis. The use of helical vanes of a substantial circumferential extent (more than 2 complete turns) enables even a freely rotatable element to impart a substantial rotational motion to the flow of air generated upon inhalation.

It will be appreciated that reference is made to the helical vanes extending "in combination" around more than 2 complete turns because it is possible, for example, to provide a single helical vane which has, say, 3 complete turns or three separate helical vanes each of which has 1 complete turn.

The pitch of the helical vanes may be constant or may vary along the axis of rotation; the pitch is preferably in the range between 20 and 750 and more preferably between 100 and 450. The one or more helical vanes preferably extend around not more than 15 complete turns.

The powder inhaler according to the second aspect of the invention may also incorporate any of the features described above with respect to the first aspect of the invention.

According to a third aspect of the invention, there is provided a powder inhaler including a deflecting device mounted in an air conduit of the inhaler, the deflecting device comprising one or more rotatable air deflecting elements whose paths of rotation sweep a part only of the cross-section of the air conduit leaving a space between the area swept by the elements and the boundary of the air conduit. Upon rotation of the deflecting elements regions of high and low pressure are preferably generated in the air conduit leading to an airflow through the conduit that promotes the breaking up of powder particles.

The rotatable air deflecting elements may be turbine blades and/or propellers. The elements may generate a region of high pressure around the deflecting elements. The airflow towards the nozzle outlet may pass principally around the outside of the air deflecting elements; in such a case the breaking up of the particles is enhanced by the nature of the airflow and very clearly not by any contact with the air deflecting elements.

The powder inhaler according to the third aspect of the invention may also incorporate any of the features described above with respect to the f irst aspect of the invention.

The invention can be provided in a nozzle unit that is separately attachable to the body of an inhaler. Thus the present invention further provides a nozzle unit for an inhaler as defined above.

The invention also provides a deflector unit for use in an inhaler device, the unit having a part comprising at least one deflecting surface, the part being rotatably mounted in a conduit which extends through the unit wherein the mounting means and the at least one deflecting surface are so arranged that, in use of the unit in the inhaler device, the at least one deflecting surface is rotatable and can alter substantially a flow of air through the conduit. The dimensions and configuration of the unit may be so selected that the unit can form a part of a dry powder inhaler, a pressurised metered dose inhaler or a nebulizer device. The deflector unit may be arranged to be inserted between dispensing means for dispensing a powder and a nozzle outlet of an inhaler device.

The present invention further provides a method of operating a powder inhaler as defined above, in which the one or more rotatably mounted deflecting elements are caused to move during operation of the inhaler and the flow of air through the air conduit is substantially altered by the one or more deflecting devices.

By way of example certain embodiments of the invention will now be described with reference to the accompanying schematic drawings, of which:

Fig. 1 is a perspective view, partly broken away, of a first form of insert for a mouthpiece of a dry powder inhaler; Fig. 2 is a perspective view, partly broken away, of a second form of insert for a mouthpiece of a dry powder inhaler; Fig. 3 is a sectional side view of a dry powder inhaler incorporating a third form of insert; Fig. 4 is a sectional side view of a fourth form of insert f or a mouthpiece of a dry powder inhaler; Fig, 5 is a perspective view of a portion of a fifth f orm. of insert for a mouthpiece of a dry powder inhaler; and Fig. 6 is a sectional side view of a portion of a sixth form of insert for a mouthpiece of a dry powder inhaler.

Fig. 1 shows an insert 1 for a mouthpiece of a dry powder inhaler. The insert 1 may be constructed as an integral part of the mouthpiece or as a separate component fixed within the mouthpiece; in the latter case, there should preferably be no air passage between the insert and the mouthpiece. The other parts of the inhaler are not shown and are not of particular significance to this embodiment of the invention. In the body of the inhaler there is a powder dispensing device, an air inlet and an air conduit extending from the air inlet to the insert 1. The powder dispensing device is arranged to dispense powder into the air conduit upstream of the insert 1. The inhaler body may take any of various wellknown forms including but not limited to that shown in US 4907583.

The insert 1 comprises a solid cylindrical outer wall 2, only part of which is shown in Fig. 1, at each end of which a three armed spider 3 is provided, each spider providing at its centre a bearing for supporting a shaft 5 carrying a helical member 4. The periphery of the helical member 4 terminates close to but clear of the cylindrical outer wall 2.

The interior of the wall 2 defines the wall of the air conduit through which powder that has been dispensed and is - 15 entrained in the airflow is drawn when a user inhales through the mouthpiece. As will be understood the helical member which defines a continuous helical.vane is rotated by the airflow but the speed of rotation is sufficiently 5 slow that the air is caused to flow along a helical path (albeit a path of greater pitch than the pitch of the helical member 4) as it passes through the insert. The speed of rotation may be reduced by various means, some of which have been described above, in order that a rotational motion is imparted to the airflow.

In the particular example shown in Fig. 1, the helical member 4 is shown with three turns and may be regarded as three helical deflecting elements joined end-to-end. Of course the single helical member 4 could be replaced by three, or a different number of, deflecting elements each extending around 3600 or a greater or smaller angle. In the example shown the pitch of the helical member is relatively small.

In a case where there are a plurality of helical members, they may be mounted on a common shaf t or on two or more separate shafts which may be coaxial and may rotate in use in the same or different directions.

Whilst the ends of the insert shown in Fig. 1 are open except where the spider 3 is provided, it should be understood that the ends may be partly closed over, if desired, for example to direct the air flow towards or away 5 from the rotational axis.

While the wall 2 and the member 4 are shown in Fig. 1 as being of approximately constant diameter along their length, it should be understood that the diameters of the cylindrical wall 3 and/or the helical member 4 could vary along their length, if desired. For example the device could taper towards a relatively narrow outlet end or could have a relatively wide, or relatively constricted, middle portion intermediate the ends of the device.

Fig. 2 shows an insert very similar to that shown in Fig. 1. The description of the insert will therefore be confined principally to the modifications illustrated in Fig. 2 and corresponding parts will be designated by the same reference numerals as in Fig. 1. The embodiment of Fig. 2 differs from that of Fig. 1 in that in addition to the helical member 4 (shown in Fig. 2 as having four turns), the shaft 5 mounts a propeller blade 6. The propeller blade 6 is arranged to be rotated by the airflow through the insert during inhalation and is provided principally to impart a rotary movement to the shaft 5 and thereby the helical member 4. As will be understood the propeller blade 6 may cause the helical member 4 to rotate W in the same direction as in Fig. 1, but faster, (ii) in the same direction as in Fig. 1, but slower, or (iii) in the opposite direction to Fig. 1 (because the driving force on the shaft 5 generated by the propeller is greater than, and in an opposite direction to, the driving force on the shaft 5 generated by the helical member 4) Although in Fig. 2 a propeller blade 6 is shown as a second element mounted on the shaft 5, it will be understood that the propeller blade may be replaced by one or more other vaned members such as the member 4, but with the vanes having a pitch of different magnitude and/or opposite sense.

Fig. 3 shows an inhaler incorporating an arrangement similar in some respects to that shown in Fig. 1. The inhaler includes an insert 1 at its nozzle, the insert being of the kind shown in Fig. 1, but including also a ring gear 7 mounted via spokes on the bottom end of the shaft 5. The inhaler further includes a drive propeller blade 8 driving a lay shaft 9 through meshing gears 10 and 11 mounted on the propeller shaft and lay shaft respectively. A gear 12 is mounted on the other end of the lay shaft 9 and meshes with the gear 7 on the shaft 5. The inhaler of Fig. 3 is also provided with apowder storage and dispensing system 14 (indicated only diagrammatically by dotted lines) which may be of any known kind and is arranged to dispense powder into air flowing between the propeller blade 8 and the upstream end of the insert 1. The propeller blade 8 is disposed in an air inlet 15 of the inhaler and is rotated as air is drawn into the inhaler; the drive forces of the propeller blade 8 act via the gearing on the shaft 5 and may thus have any of the effects described above for the propeller blade 6 of Fig. 2.

Another possible modification is for the shaft 5 to extend the whole length of the inhaler and for the propeller blade 8 to be fixed on the end of the shaft 5.

If desired the propeller blades 6 or 8 may be replaced by a suitable source of power, such as a small electric motor or jet of compressed gas, or some other prime mover.

Fig. 4 shows an inhaler mouthpiece according to a further design modification. In this case a pair of turbines 16A, 16B are mounted on a common shaft 5, axially spaced from one another and, upon inhalation, rotate generating a region 17 of high pressure in a circumferential space provided between the blades and the wall of the mouthpiece. The airflow with the powder entrained is drawn into the high pressure region around the rotating turbines and the powder particles are broken up in 5 that region.

In the arrangement shown in Fig. 4 the airflow through the turbines 16A, 16B alone generates the turbine rotation but, if desired, some other drive such as an electric motor, a jet of compressed gas, or a propeller connected directly or indirectly to the shaft 5 may be employed. Also although turbines are shown in Fig. 4 it will be appreciated that a similar effect can be obtained using propeller blades.

Fig.5 shows an inhaler mouthpiece according to a different design. In this case there is a rotary deflecting device 18 mounted in the air conduit through the mouthpiece but the axis of rotation of the deflecting elements 19 of the device is transverse to the longitudinal axis of the conduit. In the example shown the rotary deflecting elements are in the form of turbine blades.

Fig. 6 illustrates a modification that may be made in principle to any of the mouthpieces described above. The mouthpiece is provided with a pair of helical members 4A and 4B mounted on shafts 5A and SI3 and placed side-by-side. It will be understood that three or even more members may be placed side-by-side in this way and that the members may be helical members as illustrated, propellers or other 5 deflecting members.

It will be understood from the description above that the precise form of the inhaler may take any of a wide variety of forms and that the drawings illustrate some particular examples only. It should also be understood that a feature described with respect to one embodiment may, where appropriate, be incorporated in another embodiment. For example a geared drive arrangement such as that shown in Fig. 3 may be employed in a mouthpiece of the kind illustrated in Fig. 5.

The rotary deflecting device 18 may instead be mounted with its axis of rotation parallel to the longitudinal axis of the conduit. In that case, the deflecting device may advantageously be provided with curved slots that extend along a part of the device surface to assist rotation.

where the device 18 is axially parallel with the axis of the conduit, it will generally be preferred to provide separate drive means, for example, a small electric motor or jet of compressed gas, for the rotation of the device.

Claims (46)

Claims

1. A powder inhaler including means for receiving a powder to be dispensed, means for dispensing into an air conduit S powder to be inhaled, the air conduit extending from one or more air inlets to a nozzle outlet, and a deflecting device mounted in the air conduit, wherein the deflecting device includes one or more rotatably mounted deflecting elements for altering substantially the flow of air through the conduit.

2. An inhaler according to claim 1, in which the deflecting device is provided downstream of the region at which powder is dispensed into the air conduit.

3. An inhaler according to claim 1 or 2, in which the deflecting device is provided towards that end of the air conduit which defines the nozzle outlet.

4. An inhaler according to any preceding claim, wherein at least one of the one or more deflecting elements is provided adjacent to the nozzle outlet.

S. An inhaler according to any preceding claim, in which the inhaler has a detachable nozzle unit and the deflecting device is provided in the nozzle unit.

6. An inhaler according to any preceding claim, wherein a said rotatably mounted deflecting element is arranged such that it imparts a rotational motion to the flow of air.

7. An inhaler according to any preceding claim, in which at least one of the one or more rotatably mounted deflecting elements is arranged such that it moves as a result of a flow of air generated by a person inhaling through the inhaler.

8. A powder inhaler according to any one of claims 1 to 7, in which at least one of the one or more rotatably mounted deflecting elements is arranged to be driven by a prime mover.

9. A powder inhaler according to claim 8, wherein the prime mover is a battery driven motor.

10. An inhaler according to any one of claims 1 to 9, in which at least one rotatable deflecting element is arranged to be rotated at a speed relative to the air flow that prevents axial air flow through the conduit past the deflecting element.

11. An inhaler according to claim 10, in which, in the event that the rotatable deflecting element were to rotate at a speed that allowed axial air flow through the conduit, the element would be subjected to a substantial force causing it to accelerate or decelerate.

12. An inhaler according to any preceding claim, in which the one or more rotatably mounted deflecting elements include a first element in the air conduit having a first natural rate of rotation for a given rate of inhalation through the nozzle outlet, the element being connected to a second movably mounted deflecting element driven by air flow generated upon inhalation through the nozzle outlet, that second element having a second natural rate of driving the first element for the given rate of inhalation through the nozzle outlet, the first and second natural rates being substantially different.

13. An inhaler according to claim 12, in which the magnitude and/or direction of the first and second natural rates of rotation are different.

14. An inhaler according to claim 13, in which deflecting elements of opposite pitch are mounted on the same rotatable shaft.

15. An inhaler according to any preceding claim, in which deflecting elements of differing pitch, the pitches being of the same sense, are mounted on the same rotatable shaft.

16. An inhaler according to any preceding claim, in which the deflecting elements comprise a generally helical element whose pitch varies along the axis of the shaft.

17. An inhaler according to any preceding claim, in which the deflecting device mounted in the air conduit is driven at least partly by a drive device that is driven by an air stream generated upon inhalation.

18. An inhaler according to claim 17, in which the drive device is connected to the deflecting device via a gear coupling.

19. An inhaler according to any preceding claim, in which at least one of the deflecting elements moves through a path extending substantially entirely across the crosssection of the air conduit.

20. An inhaler according to claim 19, in which at least one of the deflecting elements extends across substantially all of the crosssectional area of the air conduit.

21. An inhaler according to any preceding claim, in which at least one of the deflecting elements moves across a part only of the cross-sectional area of the air conduit.

22. An inhaler according to any preceding claim, in which a plurality of rotatably mounted deflecting elements are provided side-by-side in the air conduit.

23. An inhaler according to any preceding claim, in which at least one rotatably mounted deflecting element comprises a turbine blade.

24. An inhaler according to any preceding claim, in which at least one rotatably mounted deflecting element is provided with a low-friction surface.

25. A powder inhaler including a deflecting device mounted in an air conduit of the inhaler, the deflecting device comprising one or more generally helical vanes extending in combination around more than two complete turns, the helical vanes being mounted for rotation about their axis.

26. An inhaler according to claim 25, in which the pitch of the helical vanes is constant.

27. An inhaler according to claim 25, in which the pitch of the helical vanes varies along the axis of the vanes.

28. An inhaler according to any one of claims 25 to 27, in which the pitch is in the range between 20 and 750.

29. An inhaler according to any one of claims 25 to 28, in which the helical vanes extend in combination around less than 15 complete turns.

30. An inhaler according to any one of claims 26 to 29, in which the inhaler is also as claimed in any one of claims 1 to 24.

31. A powder inhaler including a deflecting device mounted in an air conduit of the inhaler, the deflecting device comprising one or more rotatable air deflecting elements whose paths of rotation sweep a part only of the cross- section of the air conduit leaving a space between the area swept by the elements and the boundary of the air conduit.

32. A powder inhaler according to claim 31, in which the rotatable air deflecting elements include a turbine blade.

33. A powder inhaler according to claim 31 or 32, in which the rotatable air deflecting elements include a propeller.

34. A powder inhaler according to any one of claims 27 to 33, in which the airflow towards the nozzle outlet is arranged to pass principally around the outside of the air deflecting elements.

35. A powder inhaler according to any one of claims 27 to 34, in which the inhaler is also as claimed in any one of claims 1 to 24.

36. A powder inhaler substantially as herein described with reference to and as illustrated by any of the accompanying drawings.

37. A deflector unit for use in an inhaler device, the unit having a part comprising at least one deflecting surface, the part being rotatably mounted in a conduit which extends through the unit wherein the mounting means and the at least one deflecting surface are so arranged that, in use of the unit in the inhaler device, the at least one deflecting surface is rotatable and can alter substantially 5 a flow of air through the conduit.

38. A unit according to claim 37, wherein the dimensions and configuration of the unit are so selected that the unit can form a part of a dry powder inhaler.

39. A unit according to claim 37, wherein the dimensions and configuration of the unit are so selected that the unit can form a part of a pressurised metered dose inhaler.

40. A unit according to claim 37, wherein the dimensions and configuration of the unit ate so selected that the unit can form a part of a nebulizer.

41. A unit according to any one of claims 37 to 40, in which there are deflecting elements which have one or more of the features defined in claims 6 to 22.

42. A deflector unit according to any one of claims 37 to 41, which is arranged to be inserted between dispensing means for dispensing a powder and a nozzle outlet of an inhaler device.

43. A dry powder inhaler, pressurised metered dose inhaler or nebulizer device comprising a deflector unit which is in accordance with any one of claims 37 to 42.

44. A nozzle unit for an inhaler device according to any 5 one of claims 1 to 36 and 43.

45. A nozzle unit for an inhaler device, the nozzle unit comprising a deflector unit according to any one of claims 37 to 42.

46. A method of operating a powder inhaler according to any one of claims 1 to 36, or a device according to claim 43, in which the rotatably mounted deflecting elements are caused to move during operation of the inhaler and the flow of air through the air conduit is substantially altered by the deflecting device. 15