Patent Publication Number: US-2010126507-A1

Title: Multi-dose inhaler device

Description:
The present invention relates to inhalers for the administering of medicament. The invention relates particularly to multi-dose inhalers and more particularly to inhalers which are used with piercable sealed cartridges having a plurality of medicament compartments. Such inhalers allow for the administration of predetermined doses of medicament (typically a dry powder medicament). 
     A wide variety of multi-dose inhalers are presently available on the market and they are designed for the inhalation of predetermined multiple doses of medicament by a patient. A problem often associated with multi-dose inhalers relates to the need for a cartridge comprising multiple doses of medicament to be advanced and a sealed cartridge compartment to be pierced before a dose of medicament can be dispensed. This requirement has in the past resulted in complicated and expensive mechanisms for allowing a multiple dose cartridge to be conveniently used by a patient. 
     It is an object of the present invention to provide an inhaler device which is less expensive and less complicated in construction than prior art multi-dose inhaler devices. 
     A first aspect of the present invention provides an inhaler device for dispensing medicament, the inhaler device comprising medicament extraction facilitating means comprising a resiliently displaceable member. 
     A second aspect of the present invention provides an inhaler device for dispensing medicament, the inhaler device comprising medicament extraction facilitating means wherein said means is sprung biased or is operated by a cam mechanism and displaced over a pivot. Ideally, said means is biased into a medicament extraction position allowing extraction of medicament from a medicament cartridge. Preferably said means is sprung biased by virtue of the resiliently deflectable character of the material from which said means is manufactured. 
     A third aspect of the present invention provides an inhaler device for dispensing multiple doses of medicament, the inhaler comprising means for receiving a medicament cartridge comprising a plurality of compartments containing medicament; medicament extraction facilitating means for locating adjacent or in a compartment of a received cartridge and thereby allowing an extraction of medicament from the compartment; and operating means moveable in first and second directions by a user; wherein the medicament extraction facilitating means is movable from a retracted position to an extraction position in response to movement of the operating means in the first direction, the extraction position of the medicament extraction facilitating means allowing extraction of medicament from said cartridge compartment upon inhalation by a user, and the retracted position allowing advancement of the medicament cartridge, and wherein the medicament cartridge is driven by the operating means so as to advance a cartridge compartment into a predetermined position relative to the medicament extraction facilitating means in response to movement of the operating means in the second direction. 
     Preferably, the medicament extraction facilitating means also moves from the extraction position to the retracted position in response to movement of the operating means in the second direction. 
     The medicament extraction facilitating means may preferably be formed from delrin, but ABS, nylon, polycarbonate, HDPE, LDPE or acetal may also be used. 
     It will be understood therefore that an inhaler device according to the present invention allows for a comparatively simple operation by a user through appropriate movement of the operating means. If a user wishes to inhale a dose of medicament from a cartridge within the inhaler device, then the user need only move the operating means in a first direction so as to move the extraction facilitating means to an extraction position in which medicament may be extracted from the cartridge compartment. A user may then readily move the operating means in a second direction so as to advance or index the next dose of medicament to an appropriate position. Typically, this position will be one adjacent the medicament extraction facilitating means. It will be appreciated that the operating means may drive both the advancement of the cartridge and movement of the medicament extraction facilitating means. 
     Alternatively, rather than the operating means driving the medicament extraction facilitating means into an extraction position, the medicament extraction facilitating means may be driven by the operating means so as to move the medicament extraction facilitating means from the extraction position. The medicament extraction facilitating means may be moved to a retracted position which allows for the advancement of the medicament cartridge. 
     Whilst the operating means drives the medicament extraction facilitating means to one of the extraction and retracted positions, biasing means may be provided for moving the medicament extraction facilitating means to the other of the extraction and retracted positions. The biasing means may comprise a resilient elastic member. The resilient elastic member may be provided as a cantilever arm, with one end thereof fixed to a housing of the inhaler device and a free end thereof being provided with the medicament extraction facilitating means. 
     The operating means may, alternatively, drive the medicament extraction facilitating means to both the extraction and retracted positions. Biasing means may also be provided to bias the medicament extraction facilitating means towards one of the extraction and retracted positions. 
     The operating means may drive the medicament extraction facilitating means through use of a cam arrangement. Ideally, a cam is provided on the operating means. The cam may be provided as a ramp surface. The arrangement may be such that, when the operating member is moved in the second direction, the ramp surface moves laterally in abutment with the medicament extraction facilitating means and thereby displaces the medicament extraction facilitating means. Preferably, the medicament extraction facilitating means is provided with a roller or bearing before abutment with the cam. 
     The medicament extraction facilitating means may be provided with a tubular element for locating in a cartridge compartment when the medicament extraction facilitating means is located in the extraction position. A free end of the tubular element may be provided with a piercing portion. The piercing portion may be of a frusto-conical shape. Furthermore, the arrangement of the medicament extraction facilitating means may be such that, when the medicament extraction facilitating means is located in the extraction position, the tubular element is in fluid communication with a mouthpiece of the inhaler device. This fluid communication may be made through an aperture or discontinuity in the operating means. This aperture or discontinuity is ideally aligned with a flow path through the mouthpiece when the operating means has been moved in the first direction so as to drive the medicament extraction facilitating means into the extraction position. 
     The mouthpiece may also include an opening (through which medicament is inhaled) which is provided with three helical guide vanes for imparting a swirl motion onto medicament/fluid to be inhaled. Other means for imparting a swirl motion on medicament/fluid may be provided. 
     It is also preferable for the operating means to close a flow path through the mouthpiece when the operating means is moved in the second direction. Ideally, the aperture or discontinuity is moved out of alignment with the mouthpiece flow path when the operating means is moved in the second direction. Fluid communication between the mouthpiece and the extraction facilitating means is ideally prevented when the medicament extraction facilitating means is in the retracted position. 
     Furthermore, it is preferable for the medicament extraction facilitating means to comprise a venturi. 
     It is also desirable for ratchet means to be provided for allowing the operating means to drive the medicament cartridge. The operating means may be provided with a ratchet tooth so that the medicament cartridge is moved in response to movement of the operating means in the second direction, but is not moved in response to movement of the operating means in the first direction. Said ratchet tooth may be arranged so as to engage in turn with each of a plurality of ratchet teeth provided on the medicament cartridge. 
     Ideally, said first direction is opposite to said second direction. It is also preferable for movement of the operating means in said first and second directions to comprise a movement of the operating means along a part-circular path. The part-circular path is ideally concentrically positioned relative to an annular arrangement of medicament compartments of the medicament cartridge. 
     An element of the operating means may extend through a slot in a housing of the inhaler device. The slot is ideally configured so as to allow movement of said element between opposite ends of the slot and thereby move the operating means in said first and second directions. Retaining means may be provided for preventing movement of said element of the operating means. Said retaining means may be provided on a cover for the mouthpiece, possibly as part of a cover for the mouthpiece. 
     The inhaler device may be provided with means for retaining a medicament cartridge in a required position. The retaining means may comprise the roller, wheel or bearing to press against the cartridge whilst allowing movement of the cartridge. The retaining means may be sprung biased so as to press against the medicament cartridge. The retaining means is preferably made from delrin, but may be made from ABS, nylon, polycarbonate, HDPE, LDPE or acetal. The inhaler may also comprise means for driving a dose counter in response to movement of a medicament cartridge. Said drive means may comprise one or more teeth or detents for engaging a medicament cartridge. The drive means may also comprise a gear wheel for engaging means for displaying a dose count. 
    
    
     
       Embodiments of the present invention will now be described with reference to the accompanying drawings, in which: 
         FIG. 1  is an exploded view of a first inhaler device according to the present invention; 
         FIGS. 2A-G  are perspective, front, right side, rear, left side, top and bottom views respectively of the assembled inhaler device shown in  FIG. 1 ; 
         FIG. 3  is a perspective view of a base of the inhaler shown in  FIG. 1 ; 
         FIG. 4  is a front view of the base shown in  FIG. 3 ; 
         FIG. 5  is a rear view of the base shown in  FIG. 3 ; 
         FIG. 6  is a side view of a dose counter drive gear; 
         FIG. 7  is a bottom view of the drive gear of  FIG. 6 ; 
         FIG. 8  is a bottom view of a dose indicator wheel; 
         FIG. 9  is an end view of a roller for a cartridge centring mechanism; 
         FIG. 10  is a perspective view of the roller of  FIG. 9 ; 
         FIG. 11  is a side view of a cartridge centring mechanism (shown without the roller of  FIG. 9 ); 
         FIG. 12  is a rear view of the centring mechanism of  FIG. 11 ; 
         FIG. 13  is a perspective view of the centring mechanism of  FIG. 11 ; 
         FIG. 14  is a perspective view of inhaler operating means comprising a cam strip; 
         FIG. 15  is a perspective view of a spiking component and associated roller; 
         FIG. 16  is an end view of the spiking component of  FIG. 15 ; 
         FIGS. 17A-D  are persepective, front, top and bottom views respectively of an assembled second inhaler device according to the present invention; 
         FIGS. 18A-G  are perspective, front, right side, rear, left side, top and bottom views respectively of the base of the second inhaler device; 
         FIGS. 19  A-F are perspective, front, left side, rear, top and bottom views respectively of a mouthpiece of the second inhaler device; 
         FIGS. 20A-D  are perspective, front, bottom and rear views respectively of a mouthpiece cover of the second inhaler device; 
         FIGS. 21A-D  are perspective, top, bottom and side views respectively of a dose counter wheel  26  of the second inhaler device; 
         FIGS. 22A-D  are perspective, top, bottom and side views respectively of a drive gear of the second inhaler device; 
         FIG. 23  is a perspective view of a medicament cartridge centring mechanism and associated roller of the second inhaler device; 
         FIG. 24  is a side view of the roller shown in  FIG. 23 ; 
         FIGS. 25A-G  are perspective, front, right side, rear, left side, top and bottom views respectively of an operating member of the second inhaler device; 
         FIGS. 26A-D  are perspective, bottom, right side and left side views respectively of a support arm of the second inhaler device; 
         FIGS. 27A  &amp; B are top and side views respectively of a medicament cartridge of the second inhaler device; 
         FIGS. 28A-E  are, respectively, a perspective view of a spiking component of the second inhaler device and a roller to be mounted to said component, and right side, rear, top and bottom views of the spiking component alone; 
         FIGS. 29A-G  are perspective, front, right side, rear, left side, top and bottom views respectively of a middle cover of the second inhaler device; and 
         FIGS. 30A-G  are perspective, front, right side, rear, left side, top and bottom views respectively of a top cover of the second inhaler device. 
     
    
    
     An exploded view of a first inhaler device  1  is shown in  FIG. 1  of the accompanying drawings. Various views of the inhaler device  1  in an assembled condition are shown in  FIGS. 2A-G . Individual components of the first inhaler device  1  are also shown in  FIGS. 3 to 16 . 
     The inhaler device  1  comprises an outer housing and a plurality of internal components including a cartridge having a plurality of compartments containing medicament. The housing comprises a base  2  (also shown in  FIGS. 3 to 5 ), a middle cover  4  and a top cover  6 . The housing is provided with a mouthpiece  8  and a mouthpiece Cover  10 . An aperture  14  in the front side of the housing allows for fluid communication through the mouthpiece  8  between the interior and exterior of the inhaler housing. In use, a user of the inhaler device  1  places the mouthpiece to the lips of their mouth and inhales through the mouthpiece so as to extract and inhale medicament. In an alternative embodiment, the mouthpiece  8  may be replaced with a construction suitable for nasal inhalation. 
     A further aperture  16  is provided in the rear of the housing which allows for a flow of air into the housing during inhalation of medicament by a user. The housing is also provided with a slot  18  along which a knob  20  may be moved so as to advance a cartridge of medicament within the housing and so as to displace a spiking component  22 . The mouthpiece cover  10  is pivotally mounted to the knob by means of a hinge arrangement  12 . Accordingly, the cover  10  and the knob  20  move together during actuation of the device. A single hand can be used to open the mouthpiece cover  10  and actuate the device by moving the knob  20 . Alternatively, the mouthpiece cover  10  may be pivotally mounted to the housing by means of a hinge arrangement  12 . An aperture or window  24  (see also  FIG. 2G ) is also provided in the bottom of the base  2  so that an indication of the number of doses used or the number of doses remaining can be seen provided on a dose counter wheel  26  located within the housing. 
     The wheel  26  is located on and rotatably attached to a first boss  28  upstanding from an interior surface of the base  2 . A drive gear  30  for the counter wheel  26  is rotatably mounted to a second boss  32 . The second boss upstands from the same surface as the first boss  28  and is spaced from the first boss  28  so that teeth  34  (see  FIGS. 6 and 7 ) on the lower side of the drive gear  30  engage with teeth  36  on the circumferential edge of the outer wheel  26 . In use, the drive gear  30  rotates with a medicament cartridge and, due to the engagement of the teeth  34 ,  36 , rotates the counter wheel  26  so that an appropriate indicator provided on the underside of the wheel  26  may be viewed through the window  24  and thereby provide a user with an indication of the remaining doses or the doses used. 
     A medicament cartridge  38  locates on three equi-spaced support members  40  provided on the base  2 . The medicament cartridge  38  locates above the counter wheel  26  but in the same plane as the drive gear  30 . 
     The cartridge  38  is provided as an annular ring having a plurality of compartments  42 . Each compartment contains medicament in a powder form. The annular ring comprises two operative walls—an outer operative wall and an inner operative wall. Both walls have a plurality of teeth integral therewith. The inner wall comprises a plurality of integral teeth  44  which engage with a plurality of teeth  46  provided on the perimeter of the drive gear  30 . The arrangement is such that a small number of teeth  46  are engaged at any one time with the same number of teeth  44  of the medicament cartridge  38 . Thus, as the cartridge  38  rotates whilst supported on the support members  40 , the drive gear  30  is rotated on the boss  32  by virtue of the engagement between the aforesaid teeth  44 ,  46 . 
     The engagement of the drive gear  30  with the medicament cartridge  38  also assists in retaining the cartridge  38  in a required position within the inhaler housing. The position of the medicament cartridge  38  is further retained by means of a centring mechanism  50  which presses a roller  52  against the teeth  44 . Apertures  51  in the centring mechanism  50  are snap-fitted to posts  53  upstanding from the base  2 . The posts  53  have a flange (not shown) provided on their free ends so as to retain the centring mechanism  50  on the base  2 . 
     The centring mechanism  50  is made from a resiliently displaceable member so as to allow the roller  52  to be biased against the cartridge  38 . In this way, undesirable lateral movement and/or rotation of the medicament cartridge  38  is prevented. 
     The medicament cartridge  38  is indexed from one medicament compartment  42  to the next through movement by the inhaler user of an operating member  54  (an enlarged view of which is provided in  FIG. 14 ). An element  56  of the operating member  54  extends through the slot  18  and attaches with the knob  20 . The operating member  54  comprises a ratchet tooth  58  which engages with a plurality of ratchet teeth  60  provided on the outer operative wall of the medicament cartridge  38 . The configuration and engagement of the ratchet teeth  58 ,  60  is such that, when the operating member  54  is moved in the direction of arrow A (see  FIG. 1 ) the ratchet tooth  58  of the operating member  54  abuts against an adjacent ratchet tooth  60  of the cartridge  38  and rotates the cartridge  38 ′ in the direction of arrow A. The extent of movement of the operating member  54  allowed by the slot  18  indexes the cartridge  38  by one compartment  42  (i.e. to the next compartment  42 ). The movement of the cartridge  38  will also be understood to drive the dose counter wheel  26  as already described above. 
     When the operating member  54  is moved in an opposite direction to that indicated by arrow A, the configuration of the ratchet mechanism allows the ratchet tooth  58  on the operating member  54  to ride over the ratchet teeth  60  of the cartridge  38 . The cartridge  38  is therefore not rotated by movement of the operating member  54  in a direction opposite to that indicated by arrow A. 
     The operating member  54  further comprises a sealing face plate  66  which aligns with the flow path  14  associated with the mouthpiece  8  when the operating member  54  has been moved to the fullest extent in the direction indicated by arrow A. Furthermore, the operating member  54  is provided with an aperture  68  which aligns with the flow path  14  when the operating member  54  has been moved to the fullest extend in the direction opposite to that indicated by arrow A. 
     The operating member  54  yet further comprises a camming member/strip or ramp  70  which engages with a roller  72  mounted on the spiking component  22 . In the assembled inhaler  1  the camming strip  70  is located above the roller  72  and the arrangement is such that, when the operating member  54  is moved in a direction opposite to that indicated by arrow A, the roller  72  rolls against the underside of the cam strip  70  and is pressed downwardly by the camming strip  70  so as to locate the spiking component within a previously advanced compartment  42  of medicament. In so locating the spiking component  22 , a seal provided across the top of the compartment  42  is perforated by the spiking component  22 . The spiking component  22  comprises a tubular element  80  which is located in fluid communication with the aperture  68  and flow path  14 . Thus, with the operating member  54  having been moved in a direction opposite to that indicated by arrow A, the tubular element  80  is located in a compartment containing medicament and the aperture  68  of the operating member  54  is aligned with the mouthpiece flow path  14 . Medicament may then be inhaled from the medicament compartment from the mouthpiece. 
     When the operating member  54  is moved back in the direction indicated by arrow A, the aperture  68  is moved out of alignment with the mouthpiece flow path  14 . The flow path  14  is then covered by the sealing plate  66  of the operating member  54 . Also, as the operating member  54  is moved in the direction of arrow A, the downward pressure applied by the cam  70  is released and the spiking component  22  is moved upwardly by the cam movement/spring bias of a support arm  90  upon an end of which the spiking component  22  is mounted. At an opposite end of the arm  90 , a hooking element  92  is provided for securing the arm  90  to the middle cover  4  through an aperture  94  provided in said cover  4 . The arm  90  is therefore provided as a cantilever. The arm  90  is a resiliently displaceable member, and is preferably made from delrin, but may be made from nylon, polycarbonate or acetal. 
     The above materials, among others, are also suitable for the manufacture of various other parts of the device, including, but not limited to; the spiking component  22 , the hooking element  92 , the cartridge centring mechanism  50  and the rollers  52 ,  72 . 
     It will be understood that sliding the operating member  54  in the direction of arrow A in  FIG. 1  results in moving the inhaler  1  into a closed position, whilst sliding the operating member  54  in the direction opposite to that indicated by arrow A results in moving the inhaler  1  into an open position. 
     The operating member  54  is located within the inhaler housing in a groove  98 . The groove  98  allows the operating member  54  to be displaced along the inner side of the housing (i.e. circumferential movement) whilst limiting undesirable radial movement. Although not illustrated in the drawings, the spiking component  22  comprises a venturi which is positioned so that inhalation by a user causes medicament to travel up the tubular element  80  and into the venturi before eventually entering the lungs of the user. 
     The inhaler  1  may be sealed so that once the medicament within the cartridge  38  has been used, the inhaler  1  must be discarded. Alternatively, the inhaler  1  may be provided with a lid which allows access to the interior of the inhaler and thereby allows for a replacement of the used cartridge with a fresh cartridge. Accordingly, it will be understood that the inhaler  1  may incorporate a replaceable medicament cartridge so that, once the cartridge is exhausted, it can be replaced with a medicament cartridge which is fully loaded with medicament. 
     A second inhaler device  1 ′ according to the present invention is shown in  FIGS. 17A-D  of the accompanying drawings. Components of the second inhaler device  1 ′ are individually shown in  FIGS. 18-30  of the accompanying drawings. 
     The second inhaler device  1 ′ is a modification of the first inhaler device  1  and has the same component parts as the first inhaler device  1  albeit slightly modified in some cases as shown in the accompanying drawings and as discussed in more detail below. It will be appreciated that the basic operation and interaction of the components in the second inhaler device  1 ′ is essentially the same as in the first inhaler device  1 . 
     The principal differences between the first and second inhaler devices  1 ,  1 ′ are now discussed below. 
     Firstly, with regard to  FIG. 18  of the accompanying drawings, it will be understood that the base  2 ′ of the second inhaler device  1 ′ differs from that of the first inhaler device  1  in that four apertures  100  are provided along an upper perimeter edge  102  of the base  2 ′ in order to receive four posts  104  extending downwardly from a lower perimeter edge  106  of the middle cover  4 ′. The apertures  100  are asymmetrically positioned along the perimeter edge  102  of the base  2 ′ and the posts  104  are arranged in corresponding positions along the perimeter edge  106  of the middle cover  4 ′ so that all four posts  104  can only be simultaneously inserted within the apertures  100  when the base  2 ′ and middle cover  4 ′ are correctly aligned relative to one another. Insertion of the posts  104  into the apertures  100  secures the base  2  and middle cover  4  together. 
     The dose counter wheel  26 ′ is further provided with an aperture  110  which is alignable with a further aperture  108  extending through the base  2 ′ shown in  FIG. 21 . It will be understood that, when the dose counter wheel  26 ′ is mounted on the first boss  28 ′, it may be rotated relative to the base  2 ′ and thereby positioned so that the apertures  108 ,  110  align. An element (not shown) may then be temporarily inserted through the aligned apertures  108 ,  110  so as to prevent relevant rotation between the dose counter wheel  26 ′ and the base  2 ′ during assembly and/or storage of the second inhaler device  1 ′. 
     The mouthpiece  8  of the second inhaler device  1 ′ also includes a mouthpiece opening  112  (through which medicament is inhaled) which is provided with three helical guide vanes  114  for imparting a swirl motion onto medicament/fluid to be inhaled. Other means for imparting a swirl motion on medicament/fluid may be provided. 
     Furthermore, the knob  20 ′ (which engages with the operating member  54 ′) is provided as a integral part of the mouth piece cover  10 ′ as shown in  FIG. 20 . In use of the second inhaler device  1 ′, the mouthpiece cover  10 ′ is detached from the housing of the inhaler device  1 ′ at one end thereof by disengaging a clip element  116  on the mouthpiece cover from a lip  118  provided by the base  2 ′ and middle cover  4 ′. In so doing, the mouthpiece cover  10 ′ is rotated from the housing. This rotation is permitted by means of a hinge arrangement provided by a flexible strip of material  12 ′ integrally connecting the mouthpiece cover  10 ′ and the knob  20 ′. 
     The operating member  54 ′ of the second inhaler device  1 ′ differs from the operating member  54  of the first inhaler device  1  in that the clip  120  is orientated so as to engage and thereby support the full depth of the knob  20 ′. In the first inhaler device  1 , the knob  20  is merely supported at its centre and, accordingly, has a tendency to be pressed against the housing of the device at its upper and lower ends during use. The operating member  54 ′ of the second inhaler device also differs from that of the first inhaler device in that a second camming strip  130  is located below the aperture  68 ′. The second cam  130  is orientated so as to press the roller  72 ′ associated with the spiking component  22 ′ upwardly, thereby returning the support arm  90 ′ to an upper position within the housing (as the operating member  54 ′ is moved in a direction as indicated by arrow A in  FIG. 25F ). In this way, the arm  90 ′ is returned to its storage/retracted position by means of a camming action without the need for biasing means (such as the resilient elasticity of the arm  90 ′). In the second inhaler device  1 ′, the arm  90 ′ is returned to the retracted position by means of both the inherent elasticity of the arm  90 ′ and by the cam  130 . 
     With reference to  FIG. 29 , the under side of the middle cover  4 ′ is shown wherein it can be seen that resilient clip elements  132  project downwardly from either side of aperture  94 ′ and are provided with bosses  134  for snap-fitting into apertures  136  of the arm  90 ′. During operation of the second inhaler device  1 ′, the arm  90 ′ rotates up and down about the bosses  134 . When the arm  90 ′ is located in its upper-most position within the housing of the inhaler device  1 ′, the arm  90 ′ locates between two elements  138  projecting downwardly from the under-side of the middle cover  4 ′. In this way, the end of the arm  90 ′ distal to the apertures  136  is prevented from moving from side to side. 
     Furthermore, the middle cover  4 ′ is provided with four apertures  140  for receiving and retaining therein four pegs  142  projecting downwardly from the underside of the top cover  6 ′. In this way, the top cover  6 ′ is securable to the middle cover  4 ′. 
     Although the underside of the middle cover  4  of the first inhaler device  1  is not shown in the accompanying drawings, it comprises the same features (other than the posts  104 ) as those shown for the middle cover  4 ′ of the second inhaler device  1 ′. 
     Further minor differences between the first and second inhaler devices may be summarised as follows. 
     Firstly, the drive gear  30 ′ is provided with three apertures  150 . Secondly, the centring mechanism  50 ′ of the second inhaler device  1 ′ has an associated roller  52 ′ provided with four apertures  154  extending thereto so as to provide radially extending spokes  156 . 
     With reference to  FIG. 27 , a medicament cartridge  38 ′ is shown as comprising thirty doses of medicament. However, this cartridge  38 ′ is identical to the cartridge  38  of the first inhaler device  1 . Also, the spiking component  22 ′ and associated roller  72 ′ of the second inhaler device  1 ′ are identical to the corresponding components  22 ,  72  of the first inhaler device  1 . 
     With regard to materials of manufacture, the top cover  6 ′, middle cover  4 ′, drive gear  30 ′, dose counter  26 ′ and base  2 ′ may be manufactured from Acrylonitrile Butadiene Styrene (MF45). Also, the arm  90 ′, spike  22 ′ and associated roller  72 ′, operating member  54 ′, and centring mechanism  50 ′ and associated roller  52 ′ are manufactured from Acetyl co-polymer. Finally, the mouthpiece  8 ′ and associated cover  10 ′ are manufactured from polypropylene, and the medicament cartridge  38 ′ is manufactured from polystyrene ( 206 ). The corresponding components of the first inhaler device  1  may be manufactured from these same materials. 
     The present invention is not limited to the specific embodiment described above. Alternative arrangements and suitable materials will be apparent to a reader skilled in the art. For example, in an alternative embodiment, a dose counter is not provided. In such an inhaler, the counter wheel  26 , teeth  34  and window  24  will not be required and may be omitted. It will be understood therefore that the dose counter is an optional feature. It will also be appreciated that the spiking component  22 ,  22 ′ can be made integrally with the arm  90 ,  90 ′ so that the spiking component  22 ,  22 ′ and arm  90 ,  90 ′ are a unitary item. The arm  90 ,  90 ′ may also be pivotally connected to the remainder of the inhaler (for example, by means of the connection of hooking element  90  with the middle cover  4 ). This pivotal connection may allow the arm  90 ,  90 ′ to move to and from the retracted/storage position without a bending or other deformation of the arm  90 ,  90 ′ itself. In such an arrangement, it will be understood that no spring bias is provided by virtue of the arm material bending/deforming. Alternative means for providing spring bias (for example, a separate leaf spring) will need to be provided if the arm is to be moved by means of a spring bias. Alternatively, the arm may be moved by means other than a spring bias arrangement (for example, a camming system) as explained above.