GB2460281A - Inhaler - Google Patents

Abstract

An inhaler including a main body defining therein a container for containing medicament and a flow passage for ducting a flow of air. The container connects with the flow passage. The main body has an exterior surface defining an outlet connected with the flow passage so as to enable inhalation of said flow of air from said outlet. The inhaler has a width, length and a thickness extending in three respective mutually orthogonal 10 directions. At least before use, the thickness is no greater than substantially 3mm. Preferably, the width and length are no more than the respective dimensions of a standard credit card. A method of constructing the inhaler.

Description

-INHALER

The present invention relates to an inhaler, in particular an inhaler with reduced thickness allowing it to be constructed with the shape and size of a standard credit card.

Previously, in a number of different fields of technology, items have been resized and shaped to take the form of a standard credit card size, in particular as defined in 1S07810. Furthermore, in the field of inhalers, attempts have been made to produce miniaturised single-use inhalers, some of which even come close to credit card size dimensions. However, based on the conventional understanding of pressure drops in hydraulic pipes, it has always been assumed that the limit to miniaturising air passageways in an inhaler is relatively high. Hence, there has been no previous recognition of the possibility of reducing the thickness of the air passageways sufficiently to provide an inhaler thin enough to fit into a credit card pocket of a standard wallet.

Typically, the functional air passageway in an inhaler is a pipe of generally circular or square cross section. The circular cross section gives the minimum internal wetted area for a given cross sectional area and hence the lowest boundary losses and highest efficiencies. Following Bernoulli's principle and adding a viscous loss term, the pressure loss for a pipe is usually described by the Darcy-Weisbach equation: LU2 \P=f-p---(NIm2) Where: f is the friction coefficient * L is the pipe or passage length and, * D is the pipe diameter or hydraulic diameter given by: x cross-sectional area 2.) D= wetted perimeter The Haaland equation is an approximation to the Colebrooke-White equation used to obtain friction coefficient directly, expressed as: ) 1 0.25 2 I k 5.74 1021 + \. 3.7D Re°9 Using the hydraulic diameter in equations I and 2 allows 2 to be applied to pipes of rectangular cross section.

It is generally understood that this relation breaks down for cross sections with high aspect ratios. In particular, it is generally understood that the friction losses are much higher than would be predicted by the relation.

It is now recognised for the first time that, actually, for aspect ratios above 8:1, this relation actually over estimates the friction losses. It is now recognised for the first time that it is possible to use air passageways with aspect ratios above 8:1 such that they may be made very thin.

According to the present invention, there is provided a method of constructing an inhaler, the method including: providing a main body and forming the main body to define therein a container for containing medicament and a flow passage for ducting a flow of air, the container connecting with the flow passage; forming an exterior surface of the main body so as to define an outlet connecting with the flow passage so as to enable inhalation of said flow of air from said outlet; and where the inhaler has a width, length and a thickness extended in three respective mutually orthogonal directions, forming the inhaler such that, at least before use, the thickness is less than substantially 3mm.

According to the present invention, there is also provided an inhaler including: a main body defining therein a container for containing medicament and a flow passage for ducting a flow of air, the container connecting with the flow passage and the main body having an exterior surface defining an outlet connected with the flow passage so as to enable inhalation of said flow of air from said outlet; wherein the inhaler has a width, length and a thickness extending in three respective mutually orthogonal directions and, at least before use, the thickness is less than substantially 3mm.

Based on the new understanding of high aspect ratio air passageways it has been found that rectangular cross section passageways having a height of 3mm or less can still allow a bulk flow of air at 60 litres per minute and 4 kPa pressure drop. Hence, it is possible to construct air passageways suitable for use by a patient with asthma and to construct an inhaler of reduced thickness.

Preferably, the thickness of the inhaler is less than 2mm. Internal passageways and the outlet can be provided with a height of for instance 1.9mm. Indeed, the inhaler may be constructed as thin as 1mm with internal passageways and outlet having a height of 0.9mm whilst still providing sufficient bulk flow and low pressure drop for asthmatic use.

Preferably, the thickness of the inhaler is substantially 1.4mm with, for instance, internal passageways and an outlet having a height of substantially 1.3mm.

Preferably, the width and length correspond substantially to the respective dimensions of a standard credit card. In this respect, the standard width and length dimensions for a credit card are defined in the ID-i format ofISO78lO. They are defined as being 53.98mm and 85.60mm.

In this way, an inhaler may be provided with the width and length of a credit card and may be thin enough to fit into a credit card pocket of a standard wallet. Although inhalers have previously been constructed with lengths and widths within the dimensions of a credit card, none have been sufficiently thin to fit into a wallet.

Preferably, the outlet extends across the width and the thickness of the inhaler with an aspect ratio of at least substantially 5.

In preferred embodiments, the outlet extends across the width and the thickness of the inhaler with an aspect ratio between substantially 5 and 20, preferably between substantially 7 and 12 and most preferably substantially 10.

In this way, it becomes possible to reduce the thickness of the inhaler to no more than 3mm, less than 2mm or as small as 1mm whilst achieving a relatively low pressure drop for required inhalation flow rates.

Where the outlet is not the most restrictive part of the flow path, preferably the most restrictive part of the flow path in the flow passage similarly has an aspect ratio of at least substantially 5, preferably between substantially 5 and 20, more preferably between substantially 7 and 12 and most preferably substantially 10.

For parts of the flow passage upstream of the outlet, the aspect ratio can be calculated as the square of the total width of the channel (that being the sum of channel widths where there is more than one channel) perpendicular to air flow divided by the cross-sectional area of the channel (or the sum of cross-sectional areas) perpendicular to air flow.

The outlet preferably has a height extending across the thickness of the inhaler of between substantially 0.5mm and 2.9mm, preferably 1.3mm. In particular, the height is preferably substantially 0.1mm less than the thickness of the inhaler, allowing for substantially 0.05mm wall thickness. The flow passage preferably has a similar height to the outlet.

Preferably, at all points along the flow path length of the flow passage, the cross section of the flow passage perpendicular to the flow path has an aspect ratio greater than 5 and preferably greater than 8.

In one embodiment, the main body may include an upper surface extending in the width and length directions and defining therethrough an inlet connecting with the flow passage. The container can connect with the flow passage upstream of the outlet and the inlet can connect with the flow passage upstream of the container.

In this way, during use of the inhaler, a user inhales through the outlet so as to cause a flow of air downstream through the inlet and past the container. The stream of air can draw medicament from the container for inhalation by the user.

Preferably, the flow passage has a height in the thickness direction substantially the same as the outlet.

In order to minimise frictional loss and pressure drops, it is desirable to allow maximum cross sectional area for all air passageways. By maximising the height of the outlet and the flow passage both are substantially the same height. This is particularly convenient when constructing the inhaler as part of a laminate construction.

The flow passage may have a width which varies along its length from the inlet to the outlet and which is narrower in the vicinity of the container so as to form a venturi.

In other words, the open cross sectional area provided by the flow passage can reduce at one point so as to form the venturi. This increases flow rate and can assist in deagglomeration of medicament. Also, it can assist in drawing medicament from the container.

At least one bleed hole can be provided for connecting the container with ambient air. During the inhalation process, this allows ambient air to be drawn in through the bleed hole and subsequently through the container so as to help draw medicament from the container into the flow passage.

The bleed hole can be provided in the upper surface.

A removable sealing layer may be provided extending over the upper surface so as to seal the inlet and the at least one bleed hole.

In this way, the interior of the main body and inhaler can be protected from the external environment prior to use. Also, the sealing layer can act to prevent medicarnent escaping the container via the bleed hole.

Preferably, the container comprises at least one chamber located adjacent to the flow passage in the width direction.

In this respect, it is possible to provide a chamber on either side of the flow passage in the width direction. Each chamber can have one or more bleed hole as discussed above.

Preferably, the chambers have a height in the thickness direction substantially the same as the flow passage.

In this way, flow resistance of the chambers can be minimised. Also, laminate construction becomes advantageous.

Preferably, the inhaler further includes a key removably located in the outlet. The key can thus act to close the outlet with respect to the external environment. Preferably, the key extends upstream along the flow passage and has a feature for closing the connection between the container and the flow passage.

In this way, prior to removing the key, the key acts to retain medicament in the container. -.7-

In some embodiments, the inhaler may include a film strip within the flow passage, the film strip being folded back upon itself and releasably sealed therewith so as to form the container. A portion of the film strip may extend outwardly of the inhaler such that movement of the portion outwardly from the inhaler releases the seal and opens the container.

This provides a simple but effective way of containing and then releasing medicament.

A portion of the flow passage may form a deagglomeration section. For instance, as discussed above, a venturi can be used. Also, the main body can be arranged to further define a plurality of air inlet passages feeding into the deagglomeration section in a tangential direction so as to provide a swirling flow in the deagglomeration section forming a vortex.

This can be effective in assisting with deagglomeration of medicament.

Although the use of swirling flows for deagglomeration has been discussed previously in the prior art, the present application proposed for the first time effectively a two-dimensional swirling flow which happens within the generally planar form of the inhaler and restricted to the reduced height of the flow passage.

The flow passage can be considered as being defined between a lower surface and an upper surface, for instance, formed from the surfaces of laminate layers used in the construction of the main body. At least one of the upper surface and the lower surface can be provided with protrusions extending into the flow path provided by the flow passage.

The protrusions can be effective in assisting in deagglomeration of the medicament.

Where there are protrusions, these will reduce the available cross-sectional area, and hence, require a corresponding increase in the aspect ratio of the outer dimensions of the flow passage.

The protrusions may include a series of transverse ridges. In particular, with the ridges at least partly transverse to the air flow, the air flow and medicament is caused to move up and down and deagglomeration is assisted.

Alternatively or additionally, the protrusions may include an array of a plurality of obstructions.

Such obstructions, extending into the flow path will cause a change in direction of flow from side to side and, similar to the ridges, will assist in deagglomeration.

The flow passage may be defined to provide a flow path having a series of consecutive s-bends.

Where protrusions are provided, the protrusions may direct the air flow in an s-bend path. Alternatively or additionally, the flow passage itself may take the shape of a series of s-bends.

It is possible to form the flow passage as a single duct or alternatively a plurality, preferably two, of generally parallel ducts. Each duct may be provided with its own respective container of medicament or may be connected to the same container. Similarly, each duct may have its own air inlet or be connected to a common air inlet. Irrespective, preferably, each duct feeds to the same outlet or at least to respective outlets immediately adjacent one another and functionally equivalent to a single outlet.

In some embodiments, a positioning feature may be provided in proximity to the outlet as a guide to a user to the required oral insertion depth of the inhaler.

In this way, it can be better assured that the user will insert the inhaler correctly in his/her mouth for inhalation.

The positioning feature may comprise a secondary air inlet communicating with the flow passage. In this way, for the inhaler to be useable, the user must place his/her lips at least over (so as to block) or beyond the secondary air inlet.

In some embodiments, the inhaler may include a mouthpiece portion configured to be rearranged by folding to form a mouth piece having a height in the thickness direction greater than 3mm.

In this way, although the inhaler can still be supplied with the required reduced dimension, immediately before use, the mouthpiece portion can be rearranged to form the mouthpiece with larger dimensions. The mouthpiece having larger dimensions can be effective in ensuring the user correctly opens his/her mouth.

Preferably, the mouthpiece portion includes at least a preformed crease suitable for the rearrangement. It may also include preformed cuts.

Preferably, the mouthpiece includes a through-hole for alignment with the outlet once the mouthpiece portion has been rearranged to form the mouthpiece.

The inhaler may include a sliding portion, slidable relative to the main body from a first position to a second position wherein the sliding portion is connected to the mouthpiece portion and movement of sliding portion from the first position to the second position rearranges the mouthpiece portion to form the mouthpiece.

This provides a simple and user-friendly way of creating the mouthpiece.

In some embodiments, the mouthpiece portion may be configured to be rearranged by bending to an opposite side of the inhaler to form a mouthpiece having a height in the thickness direction greater than 3mm.

Preferably, the opposite side of the inhaler includes one or more clips for holding the bent mouthpiece portion in place when forming the mouthpiece.

In some embodiments, the inhaler may include a mouthpiece portion having a flexible tube, the main body slidably housing the tube such that the tube can be partly withdrawn outwardly of the main body.

In this way, the inhaler can still be supplied with the required size and dimensions.

However, prior to use, the tube can be withdrawn so as to form a mouthpiece with greater dimensions.

Preferably, the flexible tube includes a resilient end portion which is arranged to open resiliently, the end of the flexible tube furthest from the main body.

In this way, the mouthpiece portion can be constructed so as automatically to open out to the greater dimensions when withdrawn from the main body.

Preferably, an upper layer of the main body and a lower layer of the main body define the outlet therebetween. In some embodiments, the upper layer and the lower layer are preferably secured to each other at respective opposite sides of the outlet and are configured to flex away from each other at an intermediate portion between said respective opposite sides so as to form the outlet.

In this way, with the upper layer and lower layer adjacent to one another, the inhaler can have, when supplied, the required small height. However, immediately before -Il-use, the upper and lower layers may be flexed away from each other so as to increase the overall dimensions and form the outlet.

Preferably, the inhaler includes sprung reinforcing at the intermediate portion so as to bias the upper layer and lower layer away from each other. In this way, automatic formation of the mouthpiece can be achieved.

The inhaler may be provided with a feature, such as tape or an insert for holding the upper layer and lower layer together when supplied.

Preferably, the inhaler is constructed from biodegradable materials.

This is highly advantageous when thç inhaler is intended to be disposable.

The invention will be more clearly understood from the following description, given by way of example only with reference to the accompanying drawings, in which: Figure 1 illustrates an inhaler prior to use; Figure 2 illustrates the inhaler of Figure 1 with layers partly removed; Figure 3 illustrates the component parts of the inhaler of Figure 1; Figure 4 illustrates pressures losses for various aspect ratios; Figure 5 illustrates a medicament container formed from a film strip; Figure 6 illustrates a medicament container sealed with a film strip; Figure 7 illustrates a deagglomeration section of a flow passage; Figure 8 illustrates the use of transverse ridges for promoting deagglomeration; Figures 9, 10 and 11 illustrate various arrays of protrusions for promoting deagglomeration; Figure 12 illustrates the use of s-bend ducts for a flow passage; Figure 13 illustrates the use of a feature for ensuring correct oral insertion; Figures 14(a) and (b) illustrate a foldable mouthpiece; *1 Figure 15 illustrates a foldable mouthpiece; Figure 16 illustrates a bendable mouthpiece; Figures 17(a) and (b) illustrate a slidable portion for deploying a mouthpiece; Figures 18(a) and (b) illustrate a slidable portion for deploying a mouthpiece; Figures 19(a) and (b) illustrate a deployable tube mouthpiece; and Figures 20(a) and (b) illustrate a mouthpiece formed from flexing layers of the inhaler.

The present invention can be embodied in a number of different ways, including a variety of different preferred features.

As illustrated in Figure 1, there is provided an inhaler having in general the dimensions of a standard credit card. As iUustrated, the inhaler 2 has a generally planar form. in plan view, it has a width W and a length L. In particular, the width and length dimensions confirm to or are slightly smaller than the ID-I format of 1S078 10. In other words, the width is no greater than 53.98mm and the length is no greater than 85.60mm.

The inhaler 2 also has a thickness T which is no greater than 3mm.

Constructing the inhaler 2 with these dimensions, particularly the relatively small thickness dimension, makes the inhaler 2 particularly advantageous in terms of storage; it will be appreciated that the inhaler 2 can be stored in standard storage devices otherwise intended for credit cards and the like. However, it should also be appreciated that providing a device with these dimensions that can still function correctly as an inhaler is not at all a straight forward matter.

The inhaler 2 of Figure 1 is provided with a removable top film 4. This is illustrated partly cut away in Figure 2. **

As illustrated in Figure 3, the inhaler can be constructed from a number of sheet materials laminated together. A top layer 6 and a bottom layer 8 are laminated either side of a middle layer 10 so as to form a main body 12.

The main body 12 defines therein a flow passage 14 which, in the illustrated embodiment, extends generally centrally in a length wise direction.

Connecting with the flow passage 14 on either side are chambers 16 for containing medicament.

The flow passage 14 extends from an inlet end 14a to an outlet end 14b.

As illustrated, the flow passage 14 and chambers 16 are formed from a cutout in the middle layer 10 sandwiched between the upper layer 6 and lower layer 8. The cutout is shaped such that between the inlet end 1 4a and outlet end 1 4b of the flow passage 14, the flow passage 14 is constricted in the form of a venturi. The chambers 16 connect with the flow passage 14 at the venturi section 1 4c such that medicament in the chambers 16 can be more effectively drawn into the flow passage as a result of air flowing from the inlet end 14a to the outlet end 14b.

At an exterior surface of the main body 12, the cutout in the middle layer 10, together with the upper layer 6 and lower layer 8 forms an outlet 18 at the outlet end 1 4b of the flow passage 14.

A user is able to inhale through the outlet 18 so as to draw air and medicament from the inhaler 2.

As illustrated, the upper layer 6 is provided with an inlet 20 allowing passage of air through the upper layer 6 and into the inlet end 14a of the flow passage 14. Although a single large through-hole could be provided, in the preferred embodiment, the inlet 20 is provided as a plurality of small through-holes. In this way, in effect, a filter is provided to prevent ingress of particles into the flow passage 14.

Figure 2 illustrates part of the upper layer 6 removed so as to expose the inlet end 14a of the flow passage 14 beneath the plurality of air inlet holes forming the inlet 20.

So as to enable medicament to be drawn out of the chambers 16, one or more bleed holes 22 are also provided through the upper layer 6; these bleed holes 22 are provided opposite the chambers 16. In Figure 2, two groups of bleed holes 22 are illustrated opposite a chamber 16 which is concealed beneath the upper layer 6 with the other chamber 16 exposed as a result of the cut away illustration of the upper layer 6.

As illustrated in Figure 3, the inhaler 2 is also provided with a removable key 24 which is initially provided with the main body 12 in a state inserted through the outlet 18 and into the flow passage 14. The removable key 24 has a grip section 26 to be provided externally at the outlet end of the main body 12 and a resilient insert 28 to extend into the flow passage 14. A function of the insert 28 is to close the respective connections between the chambers 16 and the flow path 14.

In the illustrated embodiment, the insert 28 is formed with curved protrusions 30 extending outwardly in opposite directions and positioned so as to engage in the connecting passageways of the chambers 16 as illustrated in Figure 2. In this way, the protrusions 30 interact and engage with the connecting outlets of the chambers 16 to form a detent latch for the key 24.

In the illustrated embodiment, the insert 28 is formed from two opposing legs 32 which extend respectively along opposite walls of the cut out forming the flow passage 14.

As illustrated, the legs 32 have an outer shape corresponding to the shape of the walls defining the flow passage 14 so as to hold the key 24 securely in place. At least the legs 32 are constructed from a resilient material and can flex inwardly. in this way, when the key a 24 is pulled outwardly from the outlet 18 and flow passage 14, the legs 32 can flex inwardly towards each other, thereby releasing the extensions 30 from the passage ways to the chambers 16.

The inhaler is preferably supplied within a sealed pouch (not illustrated). The sealed pouch is preferably able to provide protection for the medicament in the chambers 16 against moisture. It may be manufactured from a laminated film.

In operation, having removed the inhaler 2 from the pouch, a user removes the top film 4, for instance by peeling the film off the upper surface 6 by means of a tab 4a as illustrated. As a result, the inlet 20 and bleed holes 22 are exposed. It will be appreciated that the top film 4 assures isolation of the flow passage until it is required for use and prevents medicament escaping from the bleed holes 22.

Once the key 24 has been removed, the medicament storage chambers 16 become connected to the flow passage 14. By inhaling through the outlet 18, a user creates a flow of air through the inlet 20 and downstream through the flow passage 14 from the inlet end 1 4a to the outlet end 1 4c. Air is also drawn through the bleed holes 22 and medicament housed in the chambers 16 is drawn into the main air flow in the flow passage 14. In this way, the medicament carried in the main air flow is carried out of the outlet 18 for inhalation by the user.

Typically, the medicament will be provided in dry powered form.

Deagglomeration is effected by turbulence and mixing in the air flow caused by the narrowing of the flow passage 14 at the middle section 14c where the medicament enters the air flow. Deagglomeration breaks up clumps of powdered medicament that may have formed during transport and storage so as to produce the required fine particle fraction of inhaled medicament for penetration to the correct regions of the user's lungs. a

The arrangement of the inhaler, in particular, its relatively small thickness becomes possible because of the aspect ratio of the flow passage 14 and outlet 18.

Previously, considerations of rectangular cross section passages for inhalers have been based on approximations to a circular pipe having what is known as a hydraulic diameter. On this basis, it has previously been assumed that relatively large rectangular passages are required to allow a bulk flow of air at 60 litres per minute and 40 kPa pressure drop suitable for asthmatic use.

Prior publications, such as Internal Flow Systems by D.S. Miller, indicate (for instance see page 132) that for aspect ratios above 10:1, the hydraulic diameter is generally thought to under estimate the friction losses. In other words, it was believed previously that high aspect ratios would lead to unusably high friction losses.

Figure 4 illustrates, in comparison to the pressure loss for two conventional inhalers, how the pressure loss changes with increasing aspect ratio for a small slot having a relatively small height and a large slot having a relatively large height.

As can be seen, for the larger slot, having a height of perhaps 3mm, increasing the width (and, hence, aspect ratio) quickly brings the resistance in line with a conventional inhaler.

It has been found, therefore, that, for aspect ratios above 8:1, the previous theoretical consideration of hydraulic diameter over estimates the friction losses. By providing airways between 0.5mm and 3.0mm in height, it becomes possible to allow 60 litres per minute of air flow at 4 kPa pressure drop with widths which will fit within the dimensions of a standard credit card and suitable for a general purpose medium resistance inhaler. I.

Other arrangements are possible for sealing and releasing the housed medicament into the main airway provided by the flow passage 14.

Figure 5 illustrates an arrangement having a film strip 40 which is folded back upon itself so as to releasably seal with itself at a sealing point 42 and so as to form an enclosed pocket 44 housing the medicament 46. The film strip 40 is secured to a lower surface within the inhaler, for instance the upwardly facing surface of the lower layer 8.

Thus, because of the S-shaped fold of the film strip 40, by pulling the film strip 40 outwardly from the inhaler, the seal at the sealing point 42 is broken and the medicament 46 is exposed to the main airway of the flow passage 14.

As illustrated, an inlet 48 is provided at an opposite end of the inhaler to the outlet 18 and the film strip 40 is pulled out of the inlet 48. However, it is also possible to provide arrangements where the inlet is provided on an upper surface such as with the embodiment of Figure 3 and the film strip 40 is pulled through its own opening. Similarly, the film strip 40, in other embodiments, could be pulled from the outlet 18 and indeed, could be attached to a key similar to the key 24 of the Figure 3 embodiment.

Figure 6 illustrates a similar embodiment where the container for the medicament is provided as a downwardly extending pocket 50 in an additional layer 52 of the main body.

In this arrangement, a film strip 54 is sealed to an upper surface of the extra layer 52 so as to close the pocket 50. By pulling the film strip 54 outwardly from the inhaler, the film strip 54 can be peeled away from the upper surface of the extra layer 52 so as to open the pocket 50 and exp6se the housed medicainent. As illustrated, the film strip 54 has a single fold and is pulled out of the inlet 48 in the same manner is illustrated in the Figure 5 embodiment. However, similarly, a different fold arrangement could be provided and the film strip could be pulled from its own dedicated opening or, indeed, from the outlet 18. a.

As described for Figure 3, deagglomeration of medicament is achieved by drawing medicarnent into the main air flow channel through the flow passage 14 in the region of the venturi formed in the flow passage 14.

Figure 7 illustrates an alternative arrangement in which the air inlet is provided by a plurality of openings 60 (along the edges of the inhaler as illustrated) which feed air to respective passages 62 which themselves direct air flow substantially tangentially into a mixing region at an inlet end of a flow passage. The tangential inlets induce a swirl in the flow and the resultant centrifugal acceleration will grade and separate particles by means of the vortex generation.

The arrangement may be used in conjunction with containers such as described with reference to Figures 5 and 6.

The arrangement illustrated in Figure 8 provides additional deagglomeration by means of raised turbulence inducing bars 70. These are illustrated on the upper surface of the lower layer 8 of the main body of the inhaler and may also be provided on the opposing lower surface of the upper layer 6.

As illustrated, the container for the medicament is formed from a film strip 40 in the manner described for the arrangement of Figure 5. However, the bar 70 could also be used with other embodiments, such as that of Figure 3.

Re-circulation regions form behind the bars. These promote impact and high shear of large particles in the bulk of the flow and assist in deagglomeration.

Preferably, the bars are between substantially 0.05mm to 1mm high. This depends upon the overall thickness of the inhaler and the resulting choice of height for the flow passage. The effective open cross-sectional area between the bars perpendicular to the air flow should still meet the requirements regarding aspect ratio. a,

The bars may be placed at any angle to the flow to alter the speed of re-circulation with respect to the main body of the flow and allow optimisation of particle sized distribution. Angling the bars at substantially 45 degrees to the flow enables a more stable vortex.

As illustrated, the bars are parallel to each other. However, it is also possible to provide a range of angles and fanned out to provide a series of re-circulation stages. This can be effective in broadening the range of particles that are successfully deagglomerated.

The upper and lower films may have the bars placed parallel to each other and off-set so as to create vortex pairs on the upper and lower surfaces. Alternatively, they may be placed at an angle relative to each other so as to provide swirl of the bulk flow similar to rifling of a gun barrel.

With the use of the bars 70, it is not necessary to provide the venturi shaping of the flow passage 14 by means of its narrowing at the central region I 4c. However, by using the venturi shape, the air flow speed is different for different regions along the length of the flow passage 14. As a result, the ridges formed by the bars have a different effect at different longitudinal regions of the flow passage 14 and are effective to break up particles of different sizes.

Other alternative arrangements are illustrated in Figure 9, 10 and 11.

In place of the bars or ridges of the Figure 8 arrangement, an array of individual protrusions or obstructions are provided within the flow passage 14. In this way, repeated particle impact occurs as the medicament moves along the flow path 14 to the outlet 18.

The high mass particles will preferentially impact the obstructions, promoting the generation of smaller fine particles. The obstruction angles and sizes is shown as uniform.

However, varying the design over a range of sizes and angles will allow a trade off between fine particle fraction and pressure loss through the device.

In the Figure 9 arrangement, the obstructions 80 each have a plan view cross section which is generally tear-shape. In the Figure 10 arrangement, each of the obstructions 82 has a plan view cross section with a larger widthwise extent than length wise extent. In both the Figure 9 and Figure 10 arrangement, consecutive rows of obstructions 80, 82 are off set from one another such that air/medicament passing between two obstructions of one row will tend to impact an obstruction in the next row.

Alternatively, the arrangement can be considered to create a series of S bends.

In the arrangement of Figure 11, the obstructions 84 actually take the form of curved walls forming a plurality of s-bend paths for the air/particle flow.

Of course, other shapes and sizes of obstruction are also possible.

The protrusions will reduce the available cross-sectional area for the flow of air.

Hence, the aspect ratio of the outer dimensions of the flow passage are increased accordingly such that the equivalent minimum aspect ratio for the air flow is maintained.

In the arrangements of Figure 9, 10 and 11, an air inlet is provided by openings 86 on both respective longitudinal edges of the inhaler. However, other inlets can be provided, for instance of the form illustrated in Figure 3.

The arrangements of Figures 9, 10 and 11 are also illustrated with a container formed from a film strip 40 as described with reference to Figure 5. However, the use of the obstructions 80, 82, 84 is also applicable to embodiments such as illustrated in Figure 3. Indeed, although the arrangements of Figure 9, 10 and 11 have a flow passage 14 with substantially the same width along its length, it is possible to use similar obstructions in conjunction with a flow passage 14 formed with the venturi. In this way, flow rates vary a, along the length of the flow passage 14 and the effect of the obstructions varies so as to have different effects on different particle sizes.

In the arrangement of Figure 12, the flow passage has the form, in plan-view, of a series of s-bends. Although it would be possible to provide a single flow passage with a series of s-bends in this way, the illustrated arrangement of Figure 12 has two side-by-side flow passages or ducts 90, each of which is arranged to carry half of the total air flow and half of the medicament for inhalation. By providing two parallel flow passages 90, it is possible to provide tighter bends in the S-shaped flow path.

The series of s-bends apply a centripetal force to the main body of the flow Secondary flows, caused by boundary layer effects will then act to graduate large and small particles across the width of the s-bends and preferentially impact large particles with the wall of the chamber.

The radius of each stage of the series of s-bends is shown as the same throughout the flow path length of the inhaler. However, it is also possible to provide a progression of ever decreasing radius bends from the inlet end to the outlet end; this may improve the deagglomeration characteristics.

It is possible to use this flow path arrangement with any of the medicament containers described above.

The following description relates to a number of different arrangements for mouthpieces for the inhaler, all of which can be used with various combinations of features discussed above.

In the arrangement of Figure 13, an inhaler 100 is provided with an outlet 102 for insertion into the user's mouth. As illustrated, the outlet 102 is positioned towards the upper surface of the inhaler 100 such that with the inhaler 100 inserted into the user's mouth and the lower surface resting on the user's tongue, the outlet 102 is not obscured.

A feature, such as a ridge or a hole 104 as illustrated in Figure 13, can be provided to assist the user in positioning the inhaler correctly in the mouth. In particularly, that feature can provide encouragement to the user to position the inhaler slightly further into the mouth during inhalation, i.e. so that the lips extend over the feature and over a greater area of the inhaler 100.

In the arrangement illustrated in Figure 13 where the feature is an aperture 104, the aperture 104 preferably connects to the flow passage within the inhaler 100 and provides a secondary air inlet into the flow passage. In this way, unless the user places in the inhaler in the mouth such that the lips are positioned beyond the aperture 104 or at least block the aperture 104, the inhaler 100 will not be operational. In particular, if aperture 104 remains exposed to ambient air, inhalation through the outlet 102 will merely draw air through the aperture 104 into the mouth and lungs of the user without drawing air through the rest of the inhaler 100.

It is also possible to use a thicker mouthpiece to force the user to have a more open mouth shape during inhalation. This reduces the tendency of medicament to strike the tongue. Of course, provision of a thicker mouthpiece is in conflict with providing the inhaler with the desired shape and size.

Figures 14(a) and (b) illustrate schematically an arrangement for an inhaler 110 as applied and rearranged for use.

Figure 14(a) illustrates a top part of the inhaler 110 having precuts 112 and creases 114 which allow it easily to be folded and rearranged to the form illustrated in Figure 14(b) such that a mouthpiece 116 is formed. As illustrated, a through-hole 118 is provided and this is positioned so as to align with the outlet 18 described above.

Figure 15 illustrates a simpler construction, requiring only a single fold. As illustrated, an upper portion 120 is merely folded down below the inhaler and the resulting arrangement requires a user to open the mouth more widely so as to extend the lips around the folded arrangement. A through-hole 122 is provided in alignment with the outlet 18 discussed above.

In the arrangement of Figure 16, rather than folding the mouthpiece portion provided with the inhaler, the mouthpiece portion 130 is bent, so as to be rolled over from one side of the inhaler to the other. One or more clips 132 may be provided on the side of the inhaler into which the mouthpiece portion 130 is bent so as to hold that portion in place. In the illustrated arrangement, the clips take the form of tongues under which the forward edge of the mouthpiece portion 130 is located. As with the arrangements discussed above, a through-hole 134 may be provided extending between the upper and lower surfaces of the mouthpiece portion 130 and positioned so as to become aligned with the outlet 18 of the inhaler when the mouthpiece portion 130 has been rolled to form the required mouthpiece.

The arrangements of Figure 17(a) and (b) and 18(a) and (b) include respective sliding portions 140 and 150 which have the effect of folding respective mouthpiece portions 142 and 152 to form mouthpieces 144 and 154. The Figures illustrate merely two of a variety of different arrangements of creases and cuts which can be provided in a mouthpiece portion to provide an appropriate mouthpiece. The sliding portions 140 and are arranged to slide in the lengthwise direction of the inhaler towards the outlet end of the inhaler so as to initiate the folding of the mouthpiece portion 142 and 152. The sliding portions 140 and 150 may be secured to the rest of the inhaler in any appropriate manner, for instance wrapping around the upper and lower surfaces.

As with the previous arrangements, through-holes 146 and 156 may be provided in the mouthpiece portions 142, 152 in positions for alignment with the outlet 18 of the main body of the inhaler.

The arrangement of Figures 19(a) and (b) includes an extendable mouthpiece 160.

The mouthpiece 160 is formed from a short length of flexible tube which is held inside the body of the inhaler and kept flat by the walls of the inhaler during storage. Just prior to use, the tube of the mouthpiece 160 is pulled outwardly from the inhaler. The portion 162 of the tube furthest from the body of the inhaler has a natural resilient form to which it returns once it is free from the walls of the main body of the inhaler. It provides an open cross section and provides a mouthpiece for the user which is thicker than the main body of the inhaler.

With the arrangement of Figures 20(a) and (b), two layers of the inhaler are arranged to move apart over a defined region so as to form a mouthpiece 170.

As illustrated, an upper layer 172 is provided opposite a lower layer 174. The upper layer 172 and lower layer 174 are secured to each other at opposite edge portions 176. However, in a central region, the upper layer 172 and lower layer 174 are able to separate (as the two opposite edge regions 176 move inwardly towards each other).

In the preferred arrangement, the arrangement is resilient such that the upper layer 172 and lower layer 174 naturally spring apart so as to form the mouthpiece 170. Means, such as a removable tape or a key 178 as illustrated in Figure 20(a) can be provided to hold the upper layer 172 and lower layer 174 together during storage such that the inhaler has the required dimensions. The locking piece or key 178 may include features discussed above, for instance with reference to Figure 3.

Preferably, the material around the region to be opened may need reinforcement, for instance with a metal strip or spring 180, to ensure that the mouthpiece will form correctly afier extended storage in the flat state. Also, this reinforcement can assist in providing enough rigidity to prevent the mouthpiece being flattened by the lips of the user during use. C.

Inhalers according to the present invention are preferably disposable and intended for manufacture at high volumes. Preferably, they are therefore constructed from biodegradable materials.

It should be appreciated that the device materials need to be stable for the shelf life of the device and to provide the necessary structural and barrier properties. On the other hand, the materials should biodegrade in a sensible time frame once the inhaler has been used. It is proposed, on this basis to use materials based upon polylactic acid (PLA), polyvinyl alcohol (PVA), starch based "bio-polymers" or even naturally occurring materials such as paper, cardboard or wood. It is proposed that, these materials could be protected from light or moisture until the time of use. Removal of an outer packaging layer upon use would then expose the materials to light and/or the atmosphere, thereby allowing them to degrade.

Claims (32)

1. ICLAIMS1. An inhaler including: a main body defining therein a container for containing medicament and a flow passage for ducting a flow of air, the container connecting with the flow passage and the main body having an exterior surface defining an outlet connected with the flow passage so as to enable inhalation of said flow of air from said outlet; wherein the inhaler has a width, length and a thickness extending in three respective mutually orthogonal directions and, at least before use, the thickness is no 10. greater than substantially 3mm.
2. 2. An inhaler according to claim 1 wherein the thickness is less than 2mm and preferably at least 1mm and preferably substantially 1.4mm.
3. 3. An inhaler according to claim I or 2, wherein the width and length are no more than the respective dimensions of a standard credit card.
4. 4. An inhaler according to claim 1, 2 or 3 wherein the respective dimensions of a standard credit card are defined by ID-1 format of 1S078 10.
5. 5. An inhaler according to any preceding claim wherein the respective dimensions are 53.98mm and 85.60mm.
6. 6. An inhaler according to any preceding claim wherein the outlet or any more restrictive portion of the flow passage extends across the width and the thickness of the inhaler with an aspect ratio of at least substantially 5.
7. 7. An inhaler according to claim 5 wherein the outlet or any more restrictive portion of the flow passage extends across the width and the thickness of the inhaler with an aspect ratio between substantially 5 and 20, preferably substantially 7 and 12, preferably substantially 10.
8. 8. An inhaler according to any preceding claim wherein the outlet has a height extending across the thickness of the inhaler by between substantially 0.5 and 2.9mm and preferably by substantially 1.3mm.
9. 9. An inhaler according to any preceding claim wherein the flow passage has a height in the thickness direction substantially the same as the outlet.
10. 10. An inhaler according to any preceding claim wherein at all points along the flow path length of the flow passage, the cross section of the flow passage perpendicular to the flow path has an aspect ratio greater than 5 and preferably greater than 8.
11. 11. An inhaler according to any preceding claim wherein the main body includes an upper surface extending in the width and length directions and defining there through an inlet connecting with the flow passage, the container connecting with the flow passage upstream of the outlet and the inlet connecting with the flow passage upstream of the container.
12. 12. An inhaler according to claim 11 wherein the flow passage has a width direction which varies along its length from the inlet to the outlet and which is narrower in the vicinity of the container so as to form a venturi.
13. 13. An inhaler according to claim 11 or 12 wherein the upper surface further defines therethrough at least one bleed hole connecting with the container.
14. 14. An inhaler according to claim 13 further including a removable sealing layer extending over the upper surface so as to seal the inlet and the at least one bleed hole. a..
15. 15. An inhaler according to any preceding claim wherein the container comprises at least one chamber located adjacent the flow passage in the width direction, preferably having a height in the thickness direction substantially the same as the flow passage.
16. 16. An inhaler according to any preceding claim further including: a key removably located in the outlet, extending upstream along the flow passage and having a feature for closing the connection between the container and the flow passage.
17. 17. An inhaler according to any preceding claim further including: a film strip within the flow passage, the film strip being folded back upon itself and releasably sealed therewith so as to form the container and a portion of the film strip extending outwardly of the container whereby movement of said portion outwardly from the inhaler releases the seal and opens the container.
18. 18. An inhaler according to any preceding claim wherein a portion of the flow passage forms a deagglomeration section and the main body further defines a plurality of air inlet passages feeding the deagglomeration section in a tangential direction so as to provide a vortex flow in the deagglomeration section.
19. 19. An inhaler according to any preceding claim wherein the flow passage is defined between a lower surface and an upper surface and at least one of the upper surface and the lower surface is provided with protrusions extending into the flow path provided by the flow passage.
20. 20. An inhaler according to claim 19 wherein the protrusions include one or more of a series of transverse ridges and an array of a plurality of obstructions.
21. 21. An inhaler according to any preceding claim wherein the flow passage is defined to provide a flow path having a series of consecutive s-bends.
22. 22. An inhaler according to an preceding claim wherein the flow passage includes a plurality of parallel ducts connecting with said outlets.
23. 23. An inhaler according to an preceding claim wherein a positioning feature is provided in proximity to the outlet as a guide to a user to the required oral insertion depth of the inhaler, the positioning feature preferably comprising a secondary air inlet communicating with the flow passage.
24. 24. An inhaler according to any one of claims 1 to 22 further including a mouthpiece portion configured to be arranged by folding to form a mouthpiece having a height in the thickness direction greater than 3mm, the mouthpiece portion preferably including at least a preformed crease suitable for rearrangement and further preferably including a through-hole for alignment with the outlet once rearranged.
25. 25. An inhaler according to claim 24 further including: a sliding portion, slidable relative to the main body from a first position to a second position wherein the sliding portion is connected to the mouthpiece portion and movement of the sliding portion from the first position to the second position rearranges the mouthpiece portion to form the mouthpiece.
26. 26. An inhaler according to any one of claims 1 to 22 further including: a mouthpiece portion configured to be rearranged by bending to an opposite side of the inhaler to form a mouthpiece having a height in the thickness direction greater than 3mm, the opposite side of the inhaler preferably including one or more clips for holding the bent mouthpiece portion.
27. 27. An inhaler according to any one of claims 1 to 22 further including: a mouthpiece portion having a flexible tube, the main body slidably housing the tube such that the tube can be partly withdrawn outwardly of the main body wherein the a flexible tube preferably includes a resilient end portion which is arranged to open resiliently the end of the flexible tube furthest from the main body.
28. 28. An inhaler according to any one of claims I to 22 wherein an upper layer of the main body and a lower layer of the main body define the outlet therebetween, are secured to each other at respective opposite sides of the outlet and are configured to flex away from each other at an intermediate portion between said respective opposite sides and the inhaler preferably includes spring reinforcing at the intermediate portion so as to bias the upper layer and the lower layer away from each other.
29. 29. An inhaler according to any preceding claim constructed from biodegradable materials.
30. 30. A method of constructing an inhaler, the method including: providing a main body and forming the main body to define therein a container for containing medicament and a flow passage for ducting a flow of air, the container connecting with the flow passage; forming an exterior surface of the main body so as to define an outlet connecting with the flow passage so as to enable inhalation of said flow of air from said outlet; and where the inhaler has a width, length and a thickness extending in three respective mutually orthogonal directions, forming the inhaler such that, at least before use, the thickness is no greater than substantially 3mm.
31. 31. An inhaler constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.
32. 32. A method of constructing an inhaler substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.