MXPA00009213A - Inhalation device - Google Patents

Abstract

A powder inhaler for administering powder by inhalation, comprising a chamber (58) which includes a base member (12) and a peripheral wall member (48), wherein the chamber (58) includes a first inlet (36) through which a first stream of air containing powder is in use drawn on inhalation by a user and a plurality of second inlets (66, 67, 68, 69, 100) at the junction between the base member (12) and the peripheral wall member (48) through which a plurality of second streams of air of combined lesser flow than the first stream of air are in use drawn on inhalation by the user so as to minimise retention of powder at the junction between the base member (12) and the peripheral wall member (48).

Description

INHALATION DEVICE The present invention relates to a powder inhaler, for administering powder by inhalation A number of powder inhalers are known, which use different systems to introduce a dose of powder into an air stream. Typically, the powder is inhaled into the lungs of a patient to treat, for example, asthma.

EP-A-0237507 describes one such powder inhaler. This inhaler, comprises, an inhalation channel and a nozzle, which includes an air chamber and an outlet valve, which together define a flow path through which a stream of air is drawn during inhalation by a ' user. The inhaler further comprises a metering mechanism for providing a dose of powder to the inhalation channel. During inhalation, air is first drawn in and through the inhalation channel to raise dust. The air stream containing dust is then drawn through the air chamber and out of the outlet valve of the nozzle.

REF .: 123146 Figure 1 illustrates such a powder inhaler. The inhaler comprises an inhaler unit 1 and a cover 2 which is fixed thereto by means of a thread. The inhalation unit 1, comprises a nozzle 3, which includes an outlet valve 4, an inhaler body 6 and a rotary holding portion 8 for operating a dosing mechanism, to provide doses of powder for inhalation. The body of the inhaler 6 is provided with an opening 10, which is covered with a window 11 through which an indicator wheel 42 is visible to provide an indication for the use of the inhaler.

Figure 2 illustrates, in a schematic view, the component parts disposed therein, and the body of the inhaler 6. the body of the inhaler 6 is covered with a divider 12 which is fixed thereto. For aesthetic reasons the body of the inhaler 6 is an opaque molding. The divider 12 is a transparent molding, which includes a peripheral groove 13 and an adjacent peripheral ridge 14 by which the nozzle 3 joins it. The divider 12 further includes a hanging tongue 15, a part of which forms the window 11.

Within the body of the inhaler 6, the component parts of the dosing mechanism are housed. These component parts include a metering unit 16, which comprises a member 17 having a flat surface on which a plurality of metering elements 18 are provided, and an axis 20, which extends axially from the center of the member 17 , a distribution unit 22 which comprises an inhalation channel 24 and a storage unit 26, which comprises a storage chamber 28 for storing powder. The component parts of the inhalation mechanism mentioned above are assembled by passing the inhalation channel 24 through an opening 30 in the storage unit 26 and passing the shaft 20 through the central openings 32, 34 in the unit of distribution 22 and storage unit 26, respectively. When assembled in this manner, the upper ends of the inhalation channel 24 and the storage chamber 28, pass respectively through the first and second openings 36, 38 in the divider 12. In this way, the distribution unit 22 and the storage unit 26, are in a fixed position relative to one another and the dosing unit 16 can be rotated relative to them.

In this inhaler, the storage chamber 28 is open at the bottom in such a way that when it is used, the powder is supplied to the dosing unit 16, under the action of gravity and the distribution unit 22 further comprises scrapers 40, which are elastically deflected against the surface of the member 17 of the dosing unit 16 in which the dosing elements 18 are provided. In this way, when the dosing unit 16 is rotated, the dosing elements 18, which comprise this inhaler a plurality of through holes, are filled with powder by scrapers 40. It is prevented that the powder passes through the dosing elements 18 by means of a plate (not shown) which is placed under the dosing unit 16 .

The divider 12 further includes a support member 41 for rotatably supporting an indicator wheel 42. The indicator wheel 42 includes a plurality of teeth 44 arranged around the periphery thereof, which engage with a spiral groove. or protrusion 46 on the end face of the axis 20 of the dosing unit 16. the support member 41 is configured to align the indicator wheel 42, so that a portion of the periphery thereof is disposed adjacent to the interior surface of the window 11. During use, when the dosing unit 16 is rotated, the spiral or protruding groove 46 engages with one or more of the teeth 44. on the indicator wheel 42 to rotate thereto. In this way, by providing a colored mark on the periphery of the indicator wheel 42, it is possible to provide the user with a visible indication in the window 11 for the use of the inhaler.

As illustrated in Figure 4, the nozzle 3 is fixed to the divider 12. The nozzle 3 comprises a first and second parts 48, 50, the first part 48 which is the part that is fastened to the lips of a user and the second part. part 50 which is fixed by insertion within the first part 48. The second part 50 comprises a tubular section 52 which includes one or more spiral or helical projections 54 which act to deflect the air drawn through them and thus both deagglomerate any of the large particles of entrained dust and a substantially radially directed flange 56 which provides a surface which together with the upper surface of the divider 12 defines an air chamber 58 which is in fluid communication with the inhalation channel 24 through from which the air containing dust is entrained by the inhalation of the user. The flange 56 includes an annular skirt 59 that hangs down, which is tightly fixed within the first part 48 and acts to fix the second part 50 to the first part.

During use, as described above, the powder is transferred from the storage chamber 28 to one of the dosing elements 18, and, with the rotation of the dosing unit 16, the dosing element 18 provides a dose of powder to the inhalation channel 24. In this inhaler, the dosage unit 16 is rotated, by rotating the holding portion 8 clockwise, when viewed from below, between the first and second positions separated angularly. For this purpose, the dosing unit 16 includes wedge-shaped elements 60 arranged around the periphery of the member 17 thereof and the holding portion 8 comprises an elastic member (not shown) which is configured to engage a surface axially directed 60a of one of the respective wedge-shaped elements 60 for rotating the dosing unit 16 by pushing the respective wedge-shaped element. By the rotation of the holding portion 8 in the opposite direction to the clockwise, between the first and second angularly spaced positions, the dosing unit 16 remains stationary and the elastic member is located behind the axially directed surface 60a of the wedge-shaped element 60 adjacent; the elastic member travels on an inclined surface 60b of the adjacent wedge-shaped element 60.

While this powder inhaler works perfectly, suitably, it is a purpose of the present invention to further improve the transfer of the powder through the air chamber.

Accordingly, the present invention provides a powder inhaler for administering powder by inhalation, comprising a chamber, which includes a base member and a peripheral wall member, wherein the chamber includes a first intake through the chamber. which a first air stream containing dust is entrained when used by inhalation of a user, and a plurality of second admissions at the junction between the base member and the peripheral wall member through which a plurality of second air streams of a combined flow smaller than that of the first air stream, are entrained by the inhalation of the user to minimize dust retention at the junction between the base member and the peripheral wall member.

In this way, the supplementary air currents, drawn through the second admissions, pass over an inner peripheral surface of the chamber. Preferably along the member of the peripheral wall towards the exit thereof. These supplementary air currents ensure that there are no weak or stagnant regions in the chamber. As a result, the possibility of any dust retention in the chamber is greatly reduced.

Preferably, the chamber includes a third intake through which a third air stream is entrained during use within the chamber by inhalation of the user.

More preferably, the third admission is in the base member of the chamber.

Preferably, the first and second admissions are arranged on one side of the chamber.

In this way, the air currents drawn through the first and third admissions interact particularly, effectively and the proper flow characteristics are achieved in the chamber.

Preferably, the base member and the peripheral wall member are separate components, which are joined to each other, and the second admissions comprise channels in one or both of the base member and the peripheral wall member.

Providing supplementary air currents through such channels is particularly advantageous because it is only necessary to make minor alterations to the shape of the component parts. In addition, the additional openings intended are unnecessary. In sum, such channels necessarily provide air currents at the junction between the base member and the peripheral wall member of the chamber where the stagnant regions are more likely to appear.

More preferably, the channels comprise a cavity in the outer edge of the base member.

Preferably, the plurality of second admissions are arranged in a peripheral region of the chamber, away from the first admission.

In a preferred embodiment the first admission is disposed on one side of the chamber and the plurality of second admissions are generally arranged on the opposite side of the chamber.

In this way, the regions of the chamber, in which the air stream drawn through the first intake is not suitable for passing directly, is provided with drafts of air drawn through the second admissions.

Preferably, the inhaler further comprises an evacuation member, disposed within the chamber for dislodging the powder from the interior surface thereof and wherein at least one of the plurality of second admissions is disposed adjacent the powder evacuation member to minimize the dust retention on top of it.

As it is possible for the stagnant regions to develop close to the dust evacuating member, these stagnant regions can be prevented and the retention reduced by providing at least one of the plurality of second admissions near the dust removal member.

More preferably, the inhaler further comprises a cover plate which covers the base member and includes at an outer peripheral edge thereof, at least one channel, which generally corresponds positionally to the plurality of second admissions.

In a preferred embodiment, the protective plate includes the powder evacuation member.

As it should be understood, the function of the second admissions is not the mixing or deagglomeration of the powders, but mainly, preventing the stagnant regions or the DEAD SPOTS, generated in the chamber. At most, second admissions only need to allow a relatively small amount of air through the interior of the chamber.

Preferably, the plurality of second admissions are configured such that 10 to 40% of the air entrained within the chamber is drawn through them.

More preferably, the plurality of second admissions are configured such that 20 to 35% of the air entrained within the chamber is drawn through them.

Even more preferably, the plurality of second admissions are configured such that from 20 to 30 percent of the air entrained within the chamber is drawn through them.

Preferably, the inhaler further comprises a housing, one end of which provides the base member, which includes at least one slot which is in fluid communication with the plurality of second admissions.

Preferably, the at least one groove extends circumferentially.

Preferably, the housing includes at least one groove, which is in fluid communication with the at least one groove.

More preferably, the at least one groove is disposed on an outer surface of the housing.

In a preferred embodiment the housing includes a plurality of grooves and a plurality of grooves which are in fluid communication with the respective one of the plurality of second admissions.

With this configuration, the air is easily and efficiently carried away from the atmosphere inside the chamber.

Preferably, the peripheral wall member includes at least one inwardly extending flange, which is clamped on the peripheral edge of the base member.

Preferably, the base member is circular, the peripheral wall member rotates about the base member and the peripheral wall member includes a plurality of internally extending flanges, which are spaced apart and dimensioned so that at least three quarters of the cross-sectional area of the second admissions is open for any relative position of the base member and the peripheral wall member.

In this way, the peripheral wall member, which can be part of the nozzle, can be rotated freely without interfering with the function of the second admissions. At the same time, the tabs keep the peripheral wall member secured in place.

Suitable medicaments for administration by the powder inhaler of the present invention are any that can be administered by inhalation and include, for example, β2-adrenoreceptor agonists, for example, salbutamol, terbutaline, rimiterol, fenoterol, reproterol, adrenaline, pirbuterol, isoprenaline, orciprenaline, bitolterol, salmeterol, formoterol, clenbuterol, procaterol, broxaterol, picumeterol, TA-2005, mabuterol and the like, and their esters and pharmaceutically acceptable salts; anticolinergic bronchodilators, for example, ipratropium bromide and the like; glucocorticosteroids, for example, beclomethasone, fluticasone, budesonide, tipredane, dexamethasone, betamethasone, fluocinolone, triamcinolone acetonide, mometasone and the like, and their esters and pharmaceutically acceptable salts; antiallergic drugs, for example, cromoglycate and nedocromil sodium; expectorants; mucolytics; antihistamines; cyclooxygenase inhibitors; inhibitors of leukotriene synthesis; leukotriene antagonists; inhibitors. phospholipase-A2 (PLA2); platelet aggregation factor (PAF) and prophylactic asthma antagonists; antiarrhythmic medications; tranquilizers; cardiac glycosides; hormones; antihypetensive medications; antidiabetic medications; antiparasitic medications; anticancer drugs; sedatives; analgesic medications; antibiotics; antirheumatic drugs; immunotherapy; antifungal medications; anti-hypotensive medications; vaccines; antiviral medications; proteins; polypeptides and peptides, for example peptide hormones and growth factors; vaccines of _polypeptide; enzymes; endorphins; lipoproteins and polypeptides involved in the blood coagulation cascade; vitamins; and others, for example, cell surface receptor blockers, antioxidants, free radical scavengers and organic salts of N, N'-diacetylcystin.

Preferred embodiments of the present invention will now be described below by means of an example only with reference to the accompanying drawings, in which: Figure 1 illustrates a perspective view of a known powder inhaler, illustrated with the separate lid; Figure 2 illustrates a schematic perspective view of the component parts of the inhaler of Figure 1; Figure 3 illustrates the lower part of the nozzle of an inhaler of Figure 1; Figure 4 illustrates a separate-sectioned side view of the inhaler of Figure 1; Figure 5 illustrates a perspective schematic side view of an inhaler according to a first embodiment of the present invention, illustrated with the separate lid; Figure 6 illustrates a schematic perspective view of the component parts of the mouthpiece of the inhaler of Figure 5.

Figure 7 illustrates a perspective view of the body part and the cover plate of the inhaler of Figure 5; Figure 8 illustrates a fragmented vertical sectional view (along section I-I in Figure 7) of the inhaler of Figure 5; Figure 9 illustrates a fragmentary sectional, vertical view (along section I-I in Figure 7) of the inhaler of Figure 5 with a modified mouthpiece; Figure 10 illustrates a schematic perspective view of the body part and the cover plate of an inhaler according to a second embodiment of the present invention; Y Figure 11 illustrates a perspective view of the body part and the cover plate of the inhaler of Figure .10.

Structurally, the powder inhalers according to the preferred embodiments of the present invention have many characteristics in common with the known powder inhalers, described above in relation to figures 1 to 4. For this reason, and to avoid unnecessary duplications of the description, only the structural differences will be described in detail and reference will be made to the foregoing descriptions of the known powder inhalers; similar reference d signs designate similar parts.

Figures 5 to 7 illustrate a powder inhaler or components thereof according to a first embodiment of the present invention. This embodiment is a modification of the known powder inhalers, mentioned above and differ from the known powder inhalers, described above in the construction of the nozzle 3, the body of the inhaler 6 and the divider 12 and in that it also comprises a cover plate 61, which is arranged on the divisor 12.

In this embodiment, the unit of the inhaler 1 comprises a part of the body 62, which is a single component of an opaque material, comprising both the body of the inhaler 6 and the divider 12.

As in the known powder inhalers described above, the body of the inhaler 6 includes the opening 10 through which the indicator wheel 42 is visible, with the storage unit 26 which is modified to comprise a tongue and which is form of a transparent material, a part, in this mode the distal end, of which tongue is formed and dimensioned so that when the storage unit 26 is fixed in the body of the inhaler 6 that part of the tongue fills the opening 10 In addition, as in known powder inhalers, described above, the indicator wheel rotatably supports the bottom of the divider 12 such that at least a portion of the periphery of the indicator wheel 42 is visible through the window 11.

The body of the inhaler 6 of this embodiment differs from that of that known powder inhaler, described above, in that it includes first and second grooves 63, 64 at the upper edge and the outer surface thereof, which are normally in fluid communication. with the atmosphere As in the known powder inhalers described above, the divider 12 includes a peripheral edge 14 by means of which, the nozzle 3, joins the part of the body 62. The divider 12 of this embodiment, differs from that of the known powder inhaler described above, in that it includes a first and second peripherally extending grooves 13a, 13b, which, together, extend around most of the periphery of the divider 12, adjacent to the peripheral edge 14, and are in fluid communication with the first and second grooves 63, 64 in the body of the inhaler 6 respectively. The divider 12 of this embodiment differs in addition to that of the known powder inhaler, described above in that the peripheral edge 14 includes a first to fourth channel 66, 67, 68, 69, in this mode, in the form of concave cavities at the edge peripheral peripheral of the peripheral edge 14, with the first and second channels 66, 67, which are in fluid communication with the first slot 13a and the third and fourth channels 68, 69, which are in fluid communication with the second slot 13b. The channels 66, 61, 68, 69 on the peripheral edge 14, provide air flow pathways, through which controlled amounts of air are drawn from 1 atmosphere, by the inhalation of the user, into the chamber 58 in the periphery of them. In this embodiment, the channels 66, 67, 68, 69 on the peripheral edge 14 are generally disposed diametrically opposite the outlet in the inhalation channel 24, which is that region of the air chamber 58 in which the jammed volumes. they are more likely to exist. The divider 12 of this embodiment differs in addition to that of the known powder inhaler described above, in that it includes a supplementary air intake 71, which is in a preferred embodiment in fluid communication with the atmosphere, through an opening in the wall. peripheral of the inhaler body 6.

The cover plate 61 comprises a substantially flat member 12, which covers the relatively complex figures on the upper surface of the divider 12, an externally offset detent element 74, which is connected to the flat member 72 by an elastic arm 76 and arranged for its radial movement, in a peripheral cavity 77, and a dust evacuation member 78, in this embodiment, a scraper, which is configured to contact a portion of the lower surface of the flange 58 which defines the upper surface of the air chamber 58. in this mode the cover plate 61 of a radial dimension smaller than that of the peripheral edge of the peripheral edge 14 of the divider 12. The cover plate 61 further includes first and second openings 80, 82, which correspond in position respectively at the outlet of the air inlet channel 24 and the supplementary air intake 71 and first through fourth channels 84, 85, 86, 87 which are available In the outer peripheral edge thereof, they correspond in position to the first to fourth channels 66, 67, 68, 69 in the peripheral edge 14 of the splitter 12 and the air chamber 58, whose flow paths could be blocked if, for example , the manufacturing tolerances of the nozzle 3 were such that a part of the peripherally extending nozzle 3 is around the peripheral edge of the outer surface of the cover plate 61. in this mode the first to fourth channels 84, 85, 86, 87 in the cover plate 61, are disposed upstream, in a rotational direction, of the dust evacuation member 78 such as to provide an air flow in a peripheral region of the air chamber 58 behind the cover member. dust evacuation 78, whose peripheral region is that region where the dust dislodged by the dust evacuation member 78 should preferentially accumulate. In this embodiment, the third channel 86 in the cover plate 61 is provided by the cavity 77 in which the catch member 74 is movably disposed and the others the first, second and fourth channels 84, 86, 87 comprise concave cavities in the outer peripheral edge of the cover plate 61. With this configuration, the channels 84, 85, 86, 87 in the cover plate 61 act to communicate the air flow through the channels 66, 67, 68, 69 at the edge peripheral 14 of the divider 12, to the periphery of the air chamber 58. In this embodiment, the total effective length of the first to fourth channels 84, 85, 86, 87 on the cover plate 61 is about a quarter of the extension of the peripheral edge of the cover plate 61.

In this embodiment, similar to the known powder inhaler, described above, the nozzle 3, comprises a first and second parts 48, 50. The nozzle 3 of this embodiment differs from that of the known powder inhaler, described above, in that the nozzle 3 is rotatable relative to the body portion 62 and in that the first portion 48 further includes a plurality of projections 90 directed radially inwardly, and a plurality of projections 92 directed radially outwardly. Each of the projections 90 directed radially inward, comprises a first side 90a, which looks in one direction, in this mode, in the clockwise direction when viewed from above, and a second side 90b which Look in the opposite direction to the clockwise. The inwardly directed projections 90 act to engage with the retainer element 74 on the protective plate 61 to prevent the nozzle 3 from freely rotating relative to the inhaler body whose free movement should be undesirable when a user tried to hold the nozzle 3 in place. the lips.

To rotate the nozzle 3, a sufficient rotational moment has to be applied thereto to cause the retainer member 74 to move on the projections directed toward the interior 90 of the nozzle 3. when used, by the rotation of the nozzle 3 relative to the body part 62, the lower surface of the flange 56 of the second part 50 of the nozzle 3 is rotated relative to the dust evacuation member 78, thereby causing any dust that may have accumulated on the portion of the undersurface of flange 56 immediately upstream, in a rotational direction, of dust removal member 78, be removed. The nozzle 3 of this embodiment differs in addition to that of the known powder inhaler, described above in that the first part 48 thereof, further comprises a plurality of flanges 96 directed radially inward, arranged around the lower edge thereof, by means of which, the nozzle 3 is attached to the divider 12; the inwardly directed flanges 96 that are fastened behind the lower surface of the peripheral edge 14 of the divider 12. In this embodiment, as illustrated in Figure 8, wherein the flanges 96 have a radial amplitude when they are extended to the inner radial edge of the channels 66, 67, 68, 69 on the peripheral edge 14 of the divider 12, the flanges 96 are peripherally spaced such that at least three of the channels 66, 67, 68, 69 on the peripheral edge 14 of the divider 12 are in fluid communication with respect to one of the first and second slots 13a, 13b for any relative position of the nozzle 3 and the body part 62. in a modified nozzle 3, as illustrated in Figure 9, the flanges 96 may be configured to have a smaller radial width, to extend only partially over the channels 66, 67, 68, 69 on the peripheral edge 14 of the divider 12. in this modified nozzle 3, the The flanges 96 have no specific and effective peripheral spacing, the nozzle 3 includes a single continuous flange.

The cover 2 of this embodiment differs from the cover 2 of the known powder inhaler, described above in that it is configured to rotate the nozzle upon removal. In this embodiment the cap 2 includes a plurality of elastic members 98 disposed around the inner periphery thereof, which engage the outwardly directed projections 92 in the first part 48 of the nozzle 3. The elastic members 98 extend axially and enclose an acute angle with the inner periphery of the lid 2; the distal ends of the elastic members 98 which are directed in the clockwise direction when viewed from above. By having an axial extension, the elastic members 98 are coupled to the outwardly directed projections 92, in the first part 48 of the nozzle 3, during the total period in which the cover 2 is removed, in this embodiment, by unscrewing the counterclockwise when looking from above. When used, when the lid 2 is removed, one or more of the elastic members 98 engage the respective outwardly directed projections 92 in the first part of the nozzle 3, and cause the nozzle 3 to rotate relative to the part of the mouthpiece. body 62, thereby causing the dust evacuating member 78 to remove any dust that may have accumulated on that part of the lower surface of the flange 56 of the second part 50 of the nozzle 3 upstream, in a rotational direction, from the member 'of dust eviction 78, whenever a user removes the lid 2, the nozzle 3 rotates automatically. When fixing the cover 2, in this mode by unscrewing in the opposite direction to the clockwise, the elastic members 98 deviate and travel on the outwardly directed projections 92 of the first part 48 of the nozzle 3.

Figures 9 and 10 illustrate the component parts of a powder inhaler according to a second embodiment of the present invention. This embodiment is a modification of the inhaler of the first embodiment described above and differs from the first embodiment in the construction of the divider 12 and the cover plate 61. The divisor 12 of this embodiment differs from the divisor 12 of the first embodiment in that it includes only one peripheral slot 13 adjacent to the peripheral edge 14 thereof and wherein the peripheral edge 14 includes a first to fifth channel 66, 67, 68, 69, 100. As in the first embodiment, channels 66, 67, 68, 69 , 100 on the peripheral edge 14 comprises concave cavities on the outer peripheral edge of the peripheral edge 14. The cover plate 61 of this embodiment differs from the cover plate 61 of the first embodiment in that it includes a first to third channel 84, 85, 86. As in the first embodiment, in this one mode, the second channel 85 in the cover plate 61 is provided by the cavity 77 in which the retainer element 74 is disposed movably. The cover plate 61 of this embodiment also differs from the cover plate 61 of the first embodiment in that the first and third channels 84, 86 comprise elongated cavities extending along the peripheral edge of the cover plate 61. in this embodiment, the first second and third channels 84, 85, 86 in the cover plate 61 are arranged adjacent to each other and the total effective length of the first second and third channels 84, 85, 86 is about one third of the length of the edge peripheral of the cover plate 61.

Finally, it will be understood that the present invention has been described in its preferred embodiments and can be modified in many different ways without departing from the scope of the appended claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the manufacture of the objects to which it refers. Having described the invention as above, property is claimed as contained in the following:

Claims (22)

1. A powder inhaler, for administering powder by inhalation, characterized in that it comprises a chamber, which includes a base member and a peripheral wall member, wherein the chamber includes a first adiási ca ± E ± o through the which a first air stream containing dust is entrained when used, by inhalation of a user, and a plurality of second admissions at the junction between the base member and the peripheral wall member, through which a plurality of second combined flow air streams less than the first air stream, are when used entrained by user inhalation to minimize dust retention at the junction between the base member and the peripheral wall member.

2. The inhaler of claim 1, characterized in that, the chamber includes a third intake, through which a third air stream is entrained when used, inside the chamber, by the inhalation of a user.

3. The inhaler of claim 2, characterized in that the third inlet is in the base member of the chamber.

4. The inhaler of claim 2 or 3, characterized in that the first and second admissions are arranged on one side of the chamber.

5. The inhaler of any of claims 1 to 4, characterized in that the base member and the peripheral wall member are separate components, which are joined to each other and the second admissions, comprise channels in one of both, the member of the base and the member of the peripheral wall.

6. The inhaler of claim 5, characterized in that the channels comprise cavities in a peripheral outer edge of the base member.

7. The inhaler of claim 6, characterized in that the peripheral outer edge of the base member comprises an edge that extends outwards, to which the peripheral wall member joins.

8. The inhaler of any of claims 1 to 7, characterized in that it further comprises a housing, an end of which provides the base member, which includes, at least one slot, which is in fluid communication with the plurality of second admissions.

9. The inhaler of claim 8, characterized in that the at least one groove extends around the periphery of the housing.

10. The inhaler of claims 8 or 9 characterized in that the housing includes at least one groove, which is in fluid communication with at least one groove.

11. The inhaler of claim 10, characterized in that the at least one groove is disposed on an outer surface of the housing.

12. The inhaler of claims 10 or 11, characterized in that the housing includes a plurality of grooves and a plurality of grooves, which are in fluid communication with the respective ones of the plurality of second admissions.

13. The inhaler of any of claims 1 to 12, characterized in that the plurality of second admissions are arranged in a peripheral region of the chamber, away from the first admission.

14. The inhaler of claim 13, characterized in that the first intake is disposed on one side of the chamber and the plurality of second admissions are generally arranged on the opposite side of the chamber.

15. The inhaler of any one of claims 1 to 14, characterized in that it further comprises a dust expelling member within the chamber, for dislodging the powder from an interior surface thereof and wherein at least one of the plurality d second admissions is It disposes adjacent to the dust evacuating member.

16. The inhaler of claim 15 in conjunction with claim 6, characterized in that it further comprises a cover plate, which covers the base member and includes at an outer peripheral edge thereof, at least one channel, which generally corresponds positionally to the plurality of second admissions or orifices.

17. The inhaler of claim 16, characterized in that, the cover plate includes the powder evacuating member.

18. The inhaler of any of claims 8 to 17, in conjunction with claim 7, characterized in that the peripheral wall member includes at least one flange extending inwardly, which is held on the peripheral edge of the member from the base.

19. The inhaler of claim 18, characterized in that, the base member is circular, the peripheral wall member rotates around the base member and the peripheral wall member includes a plurality of flanges that are spaced apart and sized such that at least three quarters of the cross-sectional area of the second admissions are open for any relative position of the base member and the peripheral wall member.

20. The inhaler of claims 1 to 18, characterized in that, the plurality of second admissions, are configured such that 10 to 40 percent of the air entrained within the chamber is drawn through them.

21. The inhaler of claim 20, characterized in that the plurality of second admissions is configured such that from 20 to 35 percent of the air entrained within the chamber is drawn through them.

22. The inhaler of claim 21, characterized in that the plurality of second admissions is configured such that from 25 to 30 percent of the air entrained within the chamber is drawn through them.