GB2568982A

GB2568982A - Inhaler device

Info

Publication number: GB2568982A
Application number: GB1801822.6A
Authority: GB
Inventors: Howell Michael
Original assignee: Mirror 5 Ltd
Current assignee: Mirror 5 Ltd
Priority date: 2018-02-05
Filing date: 2018-02-05
Publication date: 2019-06-05
Also published as: GB201801822D0; WO2019150074A1

Abstract

An inhaler 10 with a canister housing 18 to receive a canister 12.There is a coupling part (20, figure 5) coupled to the canister housing 18 through a pivotal coupling, allowing the coupling part to turn with respect to the canister housing 18 about an axis which is fixed with respect to the coupling member and the canister housing (fig 1, 2a, 2b). There is a hollow spacer 14 received upon and slidable with respect to the coupling part (20, fig 5). The inhaler device can be placed in a use configuration (fig 1) in which the hollow spacer and the canister housing are non-parallel and form an elbowed L shape. The inhaler can be reconfigured to a compact position (figure 3) by turning the hollow spacer 14 and coupling member about the pivotal coupling to align the hollow spacer with the canister housing 18 and sliding the hollow spacer over both the coupling member and the canister housing. The axis of the pivotal coupling may be inclined with respect to both the hollow spacer and the canister body. The coupling part (20 fig 1) and canister housing 18 may have mitred ends.

Description

Inhaler Device

The present invention relates to inhalers of the type used to deliver an active agent to the lungs of a patient. More specifically it concerns a housing for an inhaler which provides a mouthpiece and a body for receiving an aerosol canister and which is able to be changed by the user between two or more configurations, in one of which the inhaler housing is convenient to carry and store and in one of which the inhaler housing is ready for use.

Inhalers for medicament delivery are well known and very widely used, especially - but by no means exclusively - in the treatment of asthma and of chronic obstructive pulmonary disease. In a metered-dose type inhaler (MDI), a replaceable canister containing the active agent is pressurised with a propellant and is provided with a metering valve which dispenses a controlled dose of the active agent (hereinafter referred to simply as a dose) each time it is activated. The inhaler canister is carried in a housing which is typically a moulded plastics item which has a body for receiving the canister as an interference fit, and a mouthpiece. The housing is roughly L shaped in side view so that the user can place his/her lips around the mouthpiece, which extends roughly horizontally, whilst the housing's body and the inhaler canister are generally upright.

The metering valve is typically activated by manual action on the partofthe user. Forexample the user may be required to press on an exposed end of the canister to slide it a short distance into the body. This action applies pressure to a nozzle end of the canister to activate its metering valve and cause release of a dose. At the same time the user inhales so that the dose is drawn into the lungs along with a volume of air. The housing is open to the exterior to admit this volume of inhaled air. Typically the flow path for the air passes through a space in the housing body around the inhaler canister.

Many users need to carry an inhaler with them routinely. Asthma sufferers, for example, may need to keep an inhaler with them so that they can take a dose in response to an attack. This makes it desirable that the inhaler should be easy and compact to carry. For example some users may wish to be able easily to slip the inhaler into and out of a pocket of their clothing, such as a trouser pocket. The elbowed configuration of a conventional, one-piece moulded, inhaler housing makes the whole unit somewhat cumbersome, awkward to carry about the person and sometimes difficult to slip into a pocket.

Since inhalers are made and sold in large quantities, it is also commercially important to be able to package and transport them in a space-efficient manner. In this respect as well, a onepiece elbowed inhaler housing is less than optimal. Consider for example that if the housing is to be packaged in a cuboidal box, that box must have an increased width to accommodate the laterally protruding mouthpiece.

It is a common practice to attach a spacer to the mouthpiece of an inhaler housing. The spacer is typically in the form of an elongate tube defining a spacer chamber. It engages at one end with the mouthpiece of the inhaler housing and provides a further mouthpiece at its other end, so that the air/active agent combination passes though the spacer chamber before entering the user's mouth. Spacers are said to make the process easier for the user because it is not necessary to closely coordinate release of the dose with inhalation since the active agent collects in the spacer chamber and can then be inhaled from it. Spacers also reduce the speed of the active agent before its entry to the mouth, which may improve delivery of the agent to the lungs, less of the agent being deposited on the back of the throat and the upper airways.

But carrying a spacer in addition to the inhaler housing only adds to the nuisance for a user, as does the need to assemble the spacer to the housing prior to use, as a result of which many users do not persist with spacers.

The prior art includes certain inhalers which are able to be reconfigured for carrying/storage and which provide a telescopic arrangement to provide a form of spacer chamber.

US 4,637,528 - Wachinski et al. - discloses an aerosol medicament dispenser in which a cylindrical housing for receiving an aerosol container is coupled to a sleeve provided with a mouthpiece through a sliding and pivoting joint. The sleeve is telescopically mounted by engagement of a pair of pin-like projections on a pair of ears formed on the sleeve with slots in opposite side walls of the housing. The sleeve can thus be telescoped into the housing but when drawn out of it can be pivoted to form an L shape. The arrangement appears relatively complex and vulnerable to damage or malfunction, which is of course a vital concern since users' health may depend on timely treatment.

WO92/20391 - Abbott Laboratories - discloses a two-part pocket-size inhalation device in which a canister housing is coupled to an expansion chamber through an arrangement comprising pins sliding in grooves to enable the canister housing to slide telescopically into the expansion chamber to form a storage position, and to be drawn out of it and then turned about an axis normal to a plane containing the axes of both the canister housing and the expansion chamber (which are cylindrical) to ready the device for use. The robustness and reliability of the device is again open to doubt.

US 4,641,644 - Andersson et al. - discloses a pocket-size aerosol inhalation device which has a dosage dispensing position and a storage position. The device's mouthpiece is formed on a two-part telescoping deceleration chamber. A socket is provided to receive the inhaler canister. The socket is connected to an inner part of the telescoping deceleration chamber through a somewhat elaborate coupling which allows the socket itself to be received telescopically within the parts forming the deceleration chamber, its deployment involving pulling the socket out of those parts and turning it about an axis normal to a plane containing the axes of the socket and the deceleration chamber. Disadvantages of this construction include its complexity and the fact that because three different telescoping components must be received one inside another, around the inhaler canister, the lateral dimensions of the collapsed device are unavoidably increased, which does not help in providing a slim and compact device which can easily be slipped into a pocket.

GB2534986 discloses an inhaler housing having a body for receiving an inhaler canister pivotally coupled to a mouthpiece. The pivotal coupling provides a plurality of stable positions, one of them corresponding to a use configuration of the inhaler housing and another corresponding to a linear configuration which is convenient to carry and store.

A need exists for an inhaler housing which provides a spacer chamber and which can be quickly, easily and reliably reconfigured for (a) use and (b) carrying/storage.

According to a first aspect of the present invention there is an inhaler device comprising:

a canister housing shaped to receive and mount an inhaler canister;

a coupling part coupled to the canister housing through a pivotal coupling, enabling the coupling member to turn with respect to the canister housing about an axis which is fixed with respect to the coupling member and the canister housing; and a hollow spacer received upon the coupling member and slidable with respect to it, so that the inhaler device is able to be placed in a use configuration in which the hollow spacer and the canister housing are non-parallel and form an elbowed shape, and is able to be reconfigured by first turning the hollow spacer and coupling member about the pivotal coupling with respect to the canister housing, to align the hollow spacer with the canister housing, and then sliding the hollow spacer over both the coupling member and the canister housing to form a compact configuration. Another problem associated with conventional inhaler devices is that accidental depression of the cannister may cause release of a dose when it is not required.

According to a second aspect of the present invention there is an inhaler device comprising an inhaler housing for receiving an inhaler canister as a sliding fit, an abutment being provided within the inhaler housing to engage a valve member of the inhaler canister so that by depressing the canister with respect to the inhaler a user causes the valve member to be depressed by the abutment to release a dose, the inhaler device being further provided with a locking arrangement which, in a locking configuration, engages the canister to prevent its depression and so prevent release of the dose.

The locking arrangement may comprise a locking member insertable by a user into the inhaler housing to engage the canister. The male member may be formed on a cap which additionally comprises a closure part for closing a mouthpiece of the inhaler device. The cap may comprise a resiliently deformable girdle to embrace the inhaler device in order to mount the cap in the locking configuration. The cap may be a separate component from the inhaler device and removable from it. The locking member may be insertable through an opening in a wall of the canister housing. It may be configured to engage and end face of the canister to prevent its depression.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:4

Figure 1 illustrates an inhaler device embodying the present invention in a use configuration;

Figure 2a illustrates the same inhaler device in a first intermediate configuration;

Figure 2b illustrates the same inhaler device in a linear intermediate configuration;

Figure 3 illustrates the inhaler device in a compact configuration;

Figure 4a illustrates a coupling part of the inhaler device viewed from above and one side;

Figure 4b illustrates the coupling part in side view;

Figure 5 illustrates the coupling part and an end portion of a spacer of the inhaler device;

Figure 6 is scrap view of internal features of the inhaler device;

Figure 7a is a side view of the coupling part and spacer assembled to one another and cut away to reveal internal detail;

Figure 7b illustrates certain features of figure 7a to an enlarged scale;

Figure 8 illustrates the inhaler device and an inhaler canister in side view, the inhaler device being cut away to reveal internal detail;

Figure 9 illustrates a canister housing ofthe inhaler device viewed from the rear;

Figure 10 is a detail and sectional view of features within the canister housing;

Figure 11 illustrates the spacer on its own;

Figure 12 illustrates a cap for use with the inhaler device; and

Figure 13 illustrates the inhaler device in a compact configuration carrying the cap.

The embodiment ofthe invention depicted in Figures 1 to 13 is an inhaler device 10 which performs several functions:- it receives and serves to mount an inhaler canister 12;

- it provides for actuation of a metering valve carried by the inhaler canister 12 to dispense a dose;

- it directs the dose through a spacer 14 and a mouthpiece 16 formed on the spacer so that it can be inhaled through the mouthpiece by a user; and

- it provides a route for flow of inhaled air through the mouthpiece 16, so that the dose can be drawn - along with the inhaled air - into a user's lungs.

In addition, in accordance with the invention, the inhaler housing 10 is constructed such that it can be manually converted between two different configurations. In Figure 1 the inhaler housing 10 can be described as elbowed, being in this example roughly L shaped in side view. A canister housing 18 which receives the inhaler canister 12 is upright whilst the spacer 14 projects laterally from it. In this configuration the inhaler housing 10 is ready to deliver a dose to the user, and this will be referred to as the use configuration.

In the configuration depicted in Figure 3 the spacer 14 is aligned with the canister housing 18 and has been slid into it in telescopic fashion. The inhaler housing 10 is not able to be used to deliver a dose in this state but it does form a highly compact unit which is more convenient to carry and store, so this will be referred to for brevity as the compact configuration.

Two actions are required to transform the inhaler device from the use configuration of Figure 1 to the compact configuration. The canister housing 18 is first turned with respect to the spacer 14 through an angle which in this example is 180 degrees. Figure 2a shows the device in an intermediate configuration, the spacer having been turned through part of its rotational travel. These parts are coupled about an inclined axis, by virtue of which this turning action brings the canister housing 18 into alignment with the spacer 14, forming the linear intermediate configuration depicted in Figure 2b. The second action, once this alignment has been achieved, is to slide the canister housing 18 into the spacer 14, forming the compact configuration of Figure 3. Deployment of the device 10 for use is the opposite process and the reconfiguration is reversible - the device 10 can be changed from one configuration to the other and vice versa any number of times.

The construction of the inhaler device 10 will now be described in more detail.

The inhaler device 10 comprises three separate components in this embodiment, these being the spacer 14, the canister housing 18 and a coupling part 20 which is depicted in Figures 4 and 5 in particular. In the present embodiment each is a unitary plastics item and may be formed by injection moulding, or by any other suitable moulding or other manufacturing process. In other embodiments any or all of these parts could be formed from more than one component.

The coupling part 20 serves two purposes. It mounts the spacer 14, providing for its sliding movement, and it forms one half of a pivot enabling the turning action mentioned above. It takes the form of a hollow body which in this example has four slightly outwardly convex walls, complementing the sectional shape of the spacer 14. The coupling part 20 and the spacer 14 engage through an arrangement of elongate strakes 22 on one and grooves 24 on the other, enabling the required sliding movement whilst resisting turning of one part relative to the other. In the present example the strakes 22 are formed on innersurfaces of the spacer 14, running along its axial direction. The grooves are formed in a flange 26 at a first end of the coupling part 20.

The coupling part 20 and the spacer 14 are formed in a manner which provides end stops to the sliding movement of the spacer 14 in both directions of motion. The coupling part 20 is captively retained in the spacer 14. In the present embodiment this is achieved by means of first and second sets of stop bars 28, 30 carried by inner faces of the spacer 14. The first stop bars 28 abut the flange 26 when the spacer 14 is extended to form the use configuration. The second stop bars 30 abut the flange 26 when the spacer reaches the opposite limit of its travel to form the compact configuration. Initial assembly involves pushing the coupling part 20 into the spacer 14, but this having been done it is intended that these parts should resist disassembly despite a degree of rough handling. For this purpose the features forming the end stops are shaped to interlock mechanically and so resist separation of the parts.

Looking at Figure 7, the flange 26 can be seen to have an undercut 32 facing toward the first stop bars 28, these bars being formed with teeth 34 facing toward the flange 26, so that when the coupling part 20/spacer 14 are fully extended the teeth 34 engage in the undercut 32 and positively lock these parts against further extension, avoiding any tendency for the end stop features to ride over one another and so permit the device to be pulled apart.

A detent arrangement is provided which serves, once the coupling part 20 has been slid fully into the spacer 14 to form the compact configuration, to maintain it in this position until the user pulls on the spacer, disengaging the detent and extending the spacer. For this purpose the coupling part 20 has resilient fingers 36 which are defined by cut-aways 38 to either side of each resilient finger 36 and which have radially outwardly directed locking heads 38. Detent upstands 40 are formed on the inner surface of the spacer 14, so that as the coupling part 20 slides toward the second stop bars 30, the resilient fingers 36 are resiliently deformed in an inward direction somewhat as their locking heads 38 ride overthe upstands 40, and then snap back as they pass the upstands 40 to form the configuration seen in Figure 6, in which the locking heads 38 engage the upstands 40 to resist withdrawal. When the inhaler device 10 is to be readied for use, the user pulls on the spacer 14 causing the locking heads 38 to ride over the upstands 40 in the opposite direction.

In Figure 8 the axis about which the spacer 14 turns with respect to the canister housing 18 is represented by dashed line 42. This axis is inclined to both axis 44 of the canister housing 18 and axis 46 of the spacer 14. The result of the inclination of the rotational axis 18 is that turning the spacer transforms the inhaler housing 10 from the generally linear configuration of Figure 2b, in which the aforementioned axes 44, 46 are parallel, to the use configuration, in which these axes are angled. The internal angle between the spacer 14 and the canister housing 18 in the use configuration is a little more than 90 degrees, in the present embodiment, so that when the spacer 14 is placed in the user's mouth the canister housing 18 is angled slightly away from the user's face, which is found to be convenient.

In the present embodiment the pivotal coupling between the spacer 14/coupling part 20 and the canister housing 18 is formed in such a way as to define at least two stable positions. The pivotal coupling has a first stable position corresponding to the use configuration and a second stable position corresponding to the compact configuration. In the present embodiment it also has four further stable positions. The stable positions are at regular angular intervals of - in this case - 60 degrees.

The pivotal coupling is formed by engagement of male features of the spacer 14 with female features of the canister housing 18 in the present embodiment, although this could be reversed - that is, the male features could be provided on the canister housing 18 and the female features on the spacer 14.

Looking in particular at Figures 4b and 5, the male features comprise a set of lugs 48 upstanding from a first abutment face 50. The female features - best seen in Figure 9 comprise an opening 52 in a second abutment face 54 into which the lugs 48 are inserted. A snap fit is thereby formed - the mating features are somewhat stressed during insertion and then snap back to lock together. In Figure 4b it can be seen that each of the lugs 48 has a head 56 which is shaped for this purpose.

The first and second abutment faces 50, 54 are thereby brought into contact with one another. In the present embodiment these faces are flat. They move over one another as the spacer 14 is turned. It is the abutment faces 50,54 that define the inclination of the rotational axis 18 shown in Figure lb.

The male lugs 48 have a polygonal arrangement. More specifically, in the present embodiment the lugs 48 have a substantially hexagonal arrangement. Each lug 48 forms one edge of this hexagon, although each lug is separated from its neighbour so that the lugs 48 are able to deform independently of one another. In Figure 9 it can be seen that the opening 52 is shaped complementarily to the arrangement of the lugs 48, being substantially hexagonal.

In the aforementioned stable rotational positions of the spacer 14 relative to the canister housing 18, the lugs 48 are each aligned parallel to, and lie alongside, a respective edge of the hexagonal opening 52. It will be apparent that the hexagonal arrangement of the male and female features creates six such stable positions. As the user turns the spacer, moving it away from a stable position, these features - especially but not necessarily exclusively the lugs 48 - must be deformed somewhat. The lugs 48 are bent inwards progressively as the spacer 14 is turned, stressing them and investing them with elastic potential energy. As the spacer approaches the next stable position the lugs start to move outward, toward their un-stressed positions, so that their potential energy is released - or is at least at a minimum - when the next stable position is reached. The result is that in order to turn the spacer in either direction from a stable position, the user has to exert a torque above that needed merely to overcome friction. As the spacer turns it naturally tends to stop in the stable positionsand a haptic signal is given to the user - due to a variation of reaction torque - as the spacer is moved through the stable positions. If released in a position between two stable positions, the spacer may of its own accord move to the nearest of them.

The arrangement of the male and female features need not be hexagonal. For example it could instead have the form of another polygon. Preferably this is a polygon with an even number of sides, so that stable positions corresponding to the use and compact configurations can be spaced 180 degrees apart. An octagonal arrangement may for example be used, or a square arrangement, or an oval one.

Looking now at the detail of the canister housing 18, this is an elongate part which is hollow, forming an open-ended chamber for receiving the inhaler canister 12 itself. The length of the canister housing 18 is such that the inhaler canister 12 projects from its open end, as seen in Figure 1. The canister forms a sliding fit in the canister housing 18 and can thus be depressed by the user. The inhaler canister 12 has an outlet tube 64 (see Figure 10 in particular), depression of which actuates its metering valve (not shown) to cause release of a dose through it.

Within the canister housing 18 and integrally formed with it is a nozzle element 66 carried on an arm 68. A delivery passage 70 is formed through the nozzle element 66 and is elbowed to provide an upwardly open inlet into which the outlet tube 64 of the canister is inserted, in use, and a laterally directed delivery nozzle 72 which through which the dose is dispensed into the spacer 14, in use. The form of the delivery nozzle 72 is chosen to provide a desired spray pattern, and is in the illustrated example an outwardly divergent frustum of a cone. When the inhaler canister 12 is depressed by the user, it is the arm 68 that reacts the force applied to the canister and so actuates the metering valve.

The spacer 14 (see Figure 11 in particular) is a hollow item, thus forming a chamber into which the dose is delivered and from which it is drawn by the action of the user's lungs through its mouthpiece 16.

Provision is made for air to be drawn into the spacer 14 along with the active agent as the user inhales through the mouthpiece. Air can enter through the upper end of the canister housing 18, through spaces between the housing wall and the canister 12. But in the present embodiment it can also enter through front and rear flow passages 76, 78. A lip 80 of the spacer has front and rear cut-aways 82, 84 (see Figure 5). The coupling part 20 has complementary cut-aways 82a, 84a since it would otherwise close off the cut-aways formed in the spacer, when in the use configuration. The canister housing 18 has front and rear cut aways 86, 88 (see Figure 9). When the inhaler device 10 is in the use configuration the front cut-aways 82, 86 are juxtaposed to define the front flow passage and the rear cut-aways 84, 88 are justaposed to define the rear flow passage 78.

The cut-aways 82, 84, 86, 88 are visible at the exterior of the inhaler housing and their alignment - or, in the intermediate stable positions, their non-alignment - gives the user a visual indication of whether the spacer 14 has been turned all the way to its use position.

A removable cap 90 may be provided to close the mouthpiece 16 against ingress of dirt or other contaminants and also - in the present embodiment - to lock the inhaler device 10 positively in the compact configuration. Refer in this connection to Figures 12 and 13, where the cap 90 is seen to comprise an end cover 92 for placement over the opening in the mouthpiece, having an upstand 94 to locate in the opening. An arm 96 extends from the end cover 92 to support a cap locking member 98 and a girdle 100. The girdle 100 is a snap fit around the inhaler device 10 and serves in this way to retain the cap 90 in position on the device. The cap locking member 98 prevents the cap 90 from slipping along the spacer 14 toward the mouthpiece, and in this way keeps the end cover 92 in position over the mouthpiece. But it also prevents accidental release of active agent from the canister. Refer in this regard to Figure 10 where it can be seen that a tip of the cap locking member 98 is interposed between an end face of the inhaler canister 12 and the arm 68, so that if a force is applied to the canister tending to depress it, that force is reacted through the cap locking member 98 to the arm 68, and movement ofthe canister is thereby prevented.

In certain embodiments the spacer is formed in such a manner that it is expansible - that is, it has a larger volume in the use configuration than in the compact configuration. This may be achieved by forming the spacer with two or more telescoping parts, one able to slide over the other, so that the spacer is longitudinally expansible.

The illustrated inhaler device has multiple advantages. A device that deviates from the conventional single-piece design must be configured in such a way that the user and the manufacturer can be confident it will in practice be operated in the correct manner. Incorrect use of a poorly designed device might be injurious to health. In use of the inhaler device 10, the spacer 14 must be fully extended before the user can rotate it to form the use configuration. Hence the design prevents partial or incorrect configuration of the spacer during use. Once the spacer is extended and rotation has begun, the nature of the inclined axis relative to the direction for usage actuation means that it is very difficult to release the drug unless the spacer is turned to the correct position. Despite being compact and easy to carry, the device ensures that the spacer is used on every occasion, avoiding the problem 5 mentioned above that separately formed spaced are often not used in practice. The device is equally easy to use for left and right handed individuals.

Claims

1. An inhaler device comprising:

a canister housing shaped to receive and mount an inhaler canister;

a coupling part coupled to the canister housing through a pivotal coupling, enabling the coupling part to turn with respect to the canister housing about an axis which is fixed with respect to the coupling member and the canister housing; and a hollow spacer received upon the coupling part and slidable with respect to it, so that the inhaler device is able to be placed in a use configuration in which the hollow spacer and the canister housing are non-parallel and form an elbowed shape, and is able to be reconfigured by first turning the hollow spacer and coupling member about the pivotal coupling with respect to the canister housing, to align the hollow spacer with the canister housing, and then sliding the hollow spacer over both the coupling member and the canister housing to form a compact configuration.

2. An inhaler housing as claimed in any preceding claim in which the pivotal coupling's axis is inclined with respect to both the spacer and the body.

3. An inhaler device as claimed in claim 1 or claim 2 in which the spacer and the coupling part slidably engage through an arrangement of grooves on one of the spacer and the coupling part receiving male features on the other of the spacer and the coupling part.

4. An inhaler device as claimed in any of claims 1 to 3 comprising abutments on both the coupling part and the spacer arranged to limit sliding movement of the spacer, the abutments being shaped to mechanically interlock to resist removal of the spacerfrom the coupling part.

5. An inhaler device as claimed in claim 4 in which one of the abutments has an undercut feature and the other has a male feature to be received by the undercut female feature.

6. An inhaler device as claimed in any preceding claim having a detent arrangement to maintain the spacer in an extended position with respect to the coupling part

7. An inhaler device as claimed in any preceding claim in which the pivotal coupling between the coupling part and the canister housing is formed by at least one male engagement part on one of the coupling part and the canister housing received by at least one female engagement feature on the other of the coupling part and the canister housing and is formed such that variable elastic deformation of the coupling part and/or the canister housing takes place as the spacerand coupling member are turned relative to the canister housing, investing it or them with elastic potential energy which varies with rotational position with and which has at least two minima corresponding to the rotational positions of the spacer and coupling part in the use configuration and the compact configuration respectively, so that rotation tends to stop when either of these positions is reached..

8. An inhaler device as claimed in claim 7 in which the male engagement part(s) and the female engagement feature(s), viewed along the axis, form complementary polygonal shapes.

9. An inhaler device as claimed in claim 7 or claim 8 in which the male engagement part comprises a lug with an undercut head and the female engagement feature comprises an opening to receive the lug such that its undercut head snaps into place to couple the coupling part to the canister housing.

10. An inhaler device as claimed in any preceding claim in which the canister housing and the coupling part have respective ends which are in mutual abutment, each of the said ends being cut away to form a part flow passage, the part flow passages of the canister housing and the coupling part being arranged to be aligned when the inhaler housing is in the use configuration to provide a route for entry of air to the housing and a visual confirmation that the housing has been properly configured for use.

11. An inhaler device as claimed in claim 13 in which the coupling part and the canister housing both have mitred ends which abut one another.

12. An inhaler device as claimed in any preceding claim in which the spacer comprises at least two parts movable with respect to one another to enable the spacer to be expanded in the use configuration.

13. An inhaler device as claimed in any preceding claim provided with an end cap shaped to cover the mouthpiece and provided with a projection receivable by the inhaler device to inhibit delivery of the active substance from the inhaler canister.