Mouthpiece securing assembly for a drug delivery device

Abstract

A mouthpiece securing assembly (100) for an inhalation device, comprising: a mouthpiece core (110) configured to allow a flow of liquid from an inlet end (112) through the mouthpiece core (110) to an outlet end (114); an assembly housing (120, 150) configured to substantially enclose a portion of the mouthpiece core (110) other than at least a portion of the outlet end (114), and configured to hold the mouthpiece core (110) in place; a mouthpiece seal (180) configured to extend around the mouthpiece core (110) between the mouthpiece core (110) and the assembly housing (120, 150) to provide a seal therebetween; the mouthpiece seal (180) and the assembly housing (120, 150) being further configured such that a pressure recess is formed between the mouthpiece seal (180) and the assembly housing (120, 150), whereby in use, high pressure liquid enters the pressure recess and exerts an outward pressure on the mouthpiece seal (180).

Description

TECHNICAL FIELD

[0001] The present invention relates to the atomisation of liquids. In particular, but not exclusively, the present invention relates to a mouthpiece securing assembly for a drug delivery device. The present invention also relates to an inhalation device comprising the mouthpiece securing assembly. BACKGROUND

[0002] Drug delivery devices such as soft mist inhalers (SMI) can be used to generate droplet aerosols for inhalation through the oral and pharyngeal cavities into the lungs of a patient, for nasal administration or for spraying onto the surface of the eye.

[0003] In this type of drug delivery device, a liquid drug formulation is typically stored in a reservoir. The liquid drug formulation is delivered from the reservoir through a riser to a pressure chamber, from which it is forced through a mouthpiece by pressure and then aerosolised. In this way, a drug delivery device such as an SMI is able to atomise small quantities of liquid formulation according to a required dose in a few seconds to generate an aerosol suitable for therapeutic inhalation. Furthermore, this can be achieved without the need for the use of a propellant.

[0004] The mouthpiece is typically held in place in the device by a seal and securing mechanism / structure. When the device is actuated, the liquid formulation is forced through the mouthpiece by high pressure. These high pressures are too great to potentially extrude the sealing material through any small gaps in the component parts and are too high to potentially damage the structure of the mouthpiece or cause it to be non-sealing.

[0005] In this specification, where a patent specification, other external document or other source of information is referred to, this is generally for the purpose of providing background to the features of the invention that are discussed. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction are prior art or form part of the common general knowledge in the art. SUMMARY

[0006] It is an object of the present invention to provide a mouthpiece securing assembly which goes some way towards overcoming the above disadvantages, or at least provides the public or industry with a useful choice.

[0007] It is a further object of the present invention to provide an inhalation device comprising a mouthpiece securing assembly which goes some way towards overcoming the above disadvantages, or at least provides the public or industry with a useful choice.

[0008] In a first aspect, the invention can be said broadly to consist in a mouthpiece fixing assembly for an inhalation device, the mouthpiece fixing assembly comprising: a mouthpiece core configured to allow a flow of liquid to pass from an inlet end through the mouthpiece core to an outlet end; an assembly housing configured to substantially enclose the mouthpiece core except for at least a portion of the outlet end, and the assembly housing is configured to hold the mouthpiece core in place; a mouthpiece seal configured to extend around the mouthpiece core between the mouthpiece core and the assembly housing to provide a seal between the mouthpiece core and the assembly housing; the mouthpiece seal and the assembly housing are further configured such that a pressure recess is formed between the mouthpiece seal and the assembly housing, whereby in use, high pressure liquid enters the pressure recess and exerts an outward pressure on the mouthpiece seal.

[0009] In an embodiment, the mouthpiece seal and the assembly housing are configured such that the pressure recess extends across the inlet end of the mouthpiece core and partially along the side of the mouthpiece core.

[0010] In an embodiment, the assembly housing comprises an outer portion of a side wall around the mouthpiece core extending from the outlet end along the mouthpiece core to an intermediate position, the mouthpiece retainer having an outer end wall extending beyond and over the outlet end of the mouthpiece core.

[0011] In an embodiment, the outer end wall extends completely around the outlet end of the mouthpiece core and has an aperture at substantially the centre of the end wall.

[0012] In an embodiment, the end wall is formed such that, when viewed in cross-section, the end wall has the form of a tapered recess.

[0013] In an embodiment, the mouthpiece seal extends substantially from the outlet end of the mouthpiece core along the mouthpiece core to an intermediate position between the inlet end and the outlet end and for a first length, and is in sealing contact with the side wall of the mouthpiece core for a portion of the first length, the mouthpiece seal being shaped to include a cavity formed between the outer surface of the mouthpiece core and the inner surface of the mouthpiece seal, the cavity extending up the side of the mouthpiece core for a distance.

[0014] In an embodiment, the cavity extends substantially around the entire side of the mouthpiece core.

[0015] In an embodiment, the cavity has a side wall and an inwardly facing surface which meet circumferentially around the cavity at an angle of substantially 90°.

[0016] In an embodiment, the transition between the side wall and the inwardly facing surface of the cavity is formed as a smooth curve or chamfer.

[0017] In one embodiment, the assembly housing is formed from a filter holder and a separate mouthpiece holder, the filter holder and mouthpiece holder forming the assembly housing in combination.

[0018] It is also to be understood that the application broadly includes the parts, elements and features referred to or indicated in the specification of this application, individually or collectively, and any two or more of them can make any or all combinations thereof, and that the specific integers referred to in this particular description are to be understood as being representative of all such combinations.

[0019] Accordingly, the foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes can readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents can be resorted to, falling within the scope of the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments of the application will now be described, by way of example only, with reference to the accompanying drawings in which:

[0021] Figure 1 a cross-sectional side view of a mouthpiece securing assembly according to a first embodiment of the application is shown;

[0022] Figure 2 a close-up of the cross-sectional view of the mouthpiece securing assembly shown in Figure 1

[0023] Figure 3 a close-up of the cross-sectional view of the mouthpiece securing assembly shown in Figure 1 and Figure 2 a perspective view of the mouthpiece seal shown in the mouthpiece securing assembly in

[0024] Figure 4 a cross-sectional view of a mouthpiece securing assembly according to a second embodiment of the application is shown;

[0025] Figure 5 a close-up of the cross-sectional view of the mouthpiece securing assembly shown in Figure 4 and

[0026] Figure 6 a cross-sectional view of a mouthpiece securing assembly according to a third embodiment of the application is shown. DETAILED DESCRIPTION

[0027] EMBODIMENTS

[0028] ​The mouthpiece fixing assembly 100 according to the first embodiment of the present application comprises the following main parts: a mouthpiece core or mouthpiece cap 110; a mouthpiece retainer 120; a mouthpiece seal 180; a filter retainer 150; a filter 140, and a nut 130. The mouthpiece fixing assembly 100 is incorporated into the inhalation device 10.

[0029] The overall appearance of the mouthpiece core 110 is generally cuboid (rectangular in both plan view and side view), and the mouthpiece core has an inlet end 112 and an outlet end 114. When the mouthpiece fixing assembly 100 is fitted or incorporated into the inhalation device 10, the inlet end 112 faces or is directed towards the inhalation device 10, and the outlet end 114 faces in the opposite direction. The mouthpiece core 110 is configured to allow liquid flow from the inlet end 112 through the mouthpiece core 110 to the outlet end 114. A “mouthpiece core” as defined herein is a component having an inlet end and an outlet end connected by a plurality of microstructured channels. The inlet end of the mouthpiece core comprises a filter structure comprising one or more microstructured channels in the form of a generally sawtooth shape (i.e. forming a generally sawtooth structure). In this way, the filter structure advantageously prevents any coarse debris from clogging the microstructured channels at the outlet end. The outlet end of the mouthpiece core comprises one or more ejection ports. If the mouthpiece core used has two or more ejection ports, the geometry of these ejection ports can be arranged such that two or more liquid jets exiting the ejection ports impinge on each other (i.e. collide with each other).

[0030] The mouthpiece retainer 120 comprises a retaining portion 122 that extends circumferentially around the side wall of the mouthpiece core 110 from the outlet end 114 of the mouthpiece core 110 along the mouthpiece core 110 / along the mouthpiece core down to approximately two-thirds of the distance from the inlet end 112 to the outlet end 114. The mouthpiece retainer 120 has an outer end wall 124 that extends from the retaining portion 122 beyond and over the outlet end 114 to retain the outlet end 114 of the mouthpiece core 110. The end wall 124 extends circumferentially around the retaining portion 122. The end wall is formed such that there is an aperture 126 at the centre of the end wall 124 at the outer face of the mouthpiece core 110 that forms the outlet end 114. This enables liquid to be delivered from the outlet end 114 of the mouthpiece core 110. The end wall 124 is formed such that, when viewed in cross-section, it has the form of a tapered recess 128 extending from the aperture 126, the narrower end of the taper being at the outer face of the mouthpiece core 110 that forms the outlet end 114. The inner end of the retaining portion 122 comprises an abutment surface 129 that faces the inhalation device 10.

[0031] The filter holder 150 is formed such that, in use, it extends circumferentially from the abutment surface 129 for a remaining third of the distance around the side wall of the mouthpiece section 110. The main body of the filter holder 150 extends from the abutment surface 129 towards the inhalation device 10. The main body is formed to partially overlap and enclose the mouthpiece section 110 at the inlet end 112, the gap or chamber 160 between the main body and the mouthpiece section forming part of the pressure recess as described below.

[0032] The filter holder 150 is configured to hold the filter 140 in position close to the inlet end 112 of the mouthpiece section 110. In this embodiment, both the filter 140 and the mouthpiece section 110 are cylindrical and have a common central axis. The filter 140 is received by a recess 151 in the filter holder 150, which is open at the inhalation device end to allow the filter to be inserted or removed, the filter holder 150 having a passage 156 through the centre of the filter holder 150 at the central axis to allow fluid to flow from the filter 140 to the mouthpiece section 110.

[0033] The filter holder 150 and the mouthpiece holder 120 are mutually configured such that, in use, a chamber 160 is formed between the filter holder 150 and the inlet end 122 of the mouthpiece section 110, i.e. the filter holder 150 does not directly contact the mouthpiece section 100 at the inlet end 112.

[0034] The filter holder 150 and the mouthpiece holder 120 are also mutually configured such that the chamber 160 extends in an annular fashion around the inlet end 112 and around the mouthpiece section 110 into a cavity 190 which extends along the mouthpiece section 110 for approximately half the distance between the inlet end 112 and the outlet end 114 thereof. The cavity 190 and the chamber 160 together form a pressure recess.

[0035] It can be seen that the filter holder 150 and the mouthpiece holder 120 form an assembly housing in combination. In the described and illustrated embodiment, these elements are separate and discrete (and connected in use). However, in alternative embodiments, the assembly housing can be formed as a one-piece item, or other variants of multiple pieces, as required.

[0036] As will be described in detail below in the filter sub-section, a step or recess 184 is formed on the inner side of the filter holder.

[0037] As described above, in use the filter 140 is located in the recess 151. The filter 140 has an inlet end 142 at one end facing towards the inhalation device 10 and an outlet end 144 at the other end adjacent to the mouthpiece core 110. The passage 156 allows the chamber 160 to be in fluid connection with the outlet end 144 of the filter 140. The inlet end 142 of the filter 140 is in fluid connection with the conduit 12 in the inhalation device 10.

[0038] As described above, in use the filter 140 is located in the recess 151. The filter 140 has an inlet end 142 at one end facing towards the inhalation device 10 and an outlet end 144 at the other end adjacent to the mouthpiece core 110. The passage 156 allows the chamber 160 to be in fluid connection with the outlet end 144 of the filter 140. The inlet end 142 of the filter 140 is in fluid connection with the conduit 12 in the inhalation device 10. Figure 1 As shown in Figure 1 1, the filter holder 150 is configured to have an abutment surface 152 which, in use, is in contact with the mouthpiece holder abutment surface 129, the surfaces 152 and 129 defining an abutment interface 170 between the first filter holder abutment surface 152 and the mouthpiece holder abutment surface 129. In this way, the mouthpiece core 1 10 and the chamber 160 are enclosed between the mouthpiece holder 120 and the filter holder 150.

[0039] The inlet end 142 of the filter 140 is in fluid connection with the conduit 12 in the inhalation device 10.

[0040] The mouthpiece seal 180 extends, in use, around the mouthpiece core 1 10 between the mouthpiece core 1 10, the mouthpiece holder 120 and a portion of the filter holder 150. The mouthpiece seal 180 extends around the mouthpiece core 1 10 and from the outlet end 1 14 of the mouthpiece core 1 10 along the mouthpiece core 1 10 to about half the distance between the inlet end 1 12 and the outlet end 1 14. The mouthpiece seal 180 is in sealing contact with the side wall of the mouthpiece core 1 10. The mouthpiece seal 180 has a first end 182 facing distally or away from the inhalation device 10, the first end 182 abutting the inner surface of the end wall 124 of the mouthpiece holder 120. A second end of the mouthpiece seal 180 is, in use, at the other end facing the inhalation device 10.

[0041] As shown in Figure 1 1, the filter holder 150 is configured to have an abutment surface 152 which, in use, is in contact with the mouthpiece holder abutment surface 129, the surfaces 152 and 129 defining an abutment interface 170 between the first filter holder abutment surface 152 and the mouthpiece holder abutment surface 129. In this way, the mouthpiece core 1 10 and the chamber 160 are enclosed between the mouthpiece holder 120 and the filter holder 150. Figure 1 As shown in Figure 1 1, the filter holder 150 is configured to have an abutment surface 152 which, in use, is in contact with the mouthpiece holder abutment surface 129, the surfaces 152 and 129 defining an abutment interface 170 between the first filter holder abutment surface 152 and the mouthpiece holder abutment surface 129. In this way, the mouthpiece core 1 10 and the chamber 160 are enclosed between the mouthpiece holder 120 and the filter holder 150.

[0042] The mouthpiece seal 180 extends between the mouthpiece core 110 and the retaining portion 122 and between the mouthpiece core 110 and the filter retainer 150, such that the mouthpiece seal 180 contacts the retaining portion 122 and the filter retainer 150 in a sealed manner and such that the mouthpiece seal provides a peripheral seal line at the abutment interface 170 between the first filter retainer abutment surface 152 and the mouthpiece retainer abutment surface 129.

[0043] The mouthpiece seal 180 is also shaped to include a cavity 190 formed such that the chamber 160 extends part way (approximately half way) up the side of the mouthpiece core 110.

[0044] Figure 3 A perspective view of the mouthpiece seal 180 is provided from the end of the inhalation device 10 when in use. This view shows the detail of the cavity 190 facing the inhalation device 10 at the inner end. The cavity 190 has a side wall 186 and a surface 187 which faces the inhalation device 10 in use. The side wall 186 and the surface 187 meet at an angle of 90° to form a sharp edge 188 which extends circumferentially around the cavity 190 of the mouthpiece seal. A rectangular slot 189 is formed in the mouthpiece seal for receiving the mouthpiece core 110.

[0045] The nut 130 is configured to secure the mouthpiece retainer 110 in place on the inhalation device 10. As shown in Figure 1 the nut 130 surrounds the mouthpiece retainer 120 and the filter retainer 150, in addition to the opening around the conical recess 128.

[0046] In use, a force is exerted on the mouthpiece seal 180 by the liquid in the chamber 160, as shown by the arrow in Figure 2 The liquid exerts an outward pressure on the mouthpiece seal 180, i.e. in this case "outward" means that the pressure is exerted on the mouthpiece seal 180 by the high pressure liquid in the cavity 190 on the inner surface of the seal (facing the cavity 190). This pressure enhances the seal between the mouthpiece seal 180 and the mouthpiece retainer 120 and the seal between the mouthpiece seal 180 and the filter retainer 150. This improves the radial seal between the mouthpiece retainer 120 and the mouthpiece seal 180 and the radial seal between the filter retainer 150 and the mouthpiece seal 180 and reduces any leakage of liquid from the mouthpiece securing assembly 100.

[0047] Embodiments

[0048] Figure 4 A mouthpiece securing assembly 200 according to a second embodiment of the application is shown.

[0049] The mouthpiece securing assembly 200 has substantially the same structure as the mouthpiece securing assembly 100 in the first embodiment, and similar reference numerals are used for similar elements, e.g.: mouthpiece core 110, 210; filter 140, 240; etc.

[0050] In this embodiment, the recessed portion (cavity 290) of the mouthpiece seal 280 is formed with a smooth curve or chamfer, rather than a 90 degree angle forming a sharp edge 188 as in the first embodiment. That is, the transition between the side wall and the inward facing surface of the cavity is formed as a smooth curve or chamfer. As with the first embodiment, the pressure recess is formed by the cavity 290 and the chamber 260.

[0051] Figure 4 The arrows are indicative of the direction of force exerted by the high pressure liquid in the cavity 290 on the mouthpiece seal 280 when the inhalation device 10 is in use. The chamfered edge 288 of the cavity 290 can assist in providing a more dispersed pressure distribution in the mouthpiece seal 280.

[0052] Figure 5 A perspective view of the mouthpiece seal 280 is provided from the same perspective as in Figure 3 A perspective view of the mouthpiece seal 280 is provided from the same perspective as in

[0053] Embodiment

[0054] A third embodiment of the mouthpiece securing assembly 300 is shown in Figure 6 The mouthpiece securing assembly 300 has substantially the same structure as the first and second embodiments described above and shown in Figures 1 to 5

[0055] In this embodiment, the filter holder does not have a step or recess, such as the step 184 in the first embodiment. The equivalent in this embodiment is a rail or lip 384. The filter holder 350 is formed such that the rail or lip 384 extends circumferentially around the outer or top end of the filter holder 350. The lip 384 is an extension of the main body of the filter holder 350, as shown in Figure 6 ​As shown in FIG. 12, the lip 384 has a recess or indentation formed in the interior of the perimeter of the lip 384, into which the lower or inner end of the mouthpiece core 310 and the lower or inner end of the mouthpiece seal are located. In this embodiment, the body of the seal 380 is longer than the seal in the previous embodiments, and the seal extends completely down the length of the interior surface of the lip 384 to the surface of the recess / indentation in the filter holder 350.

[0056] As shown in FIG. 12, the lip 384 has a recess or indentation formed in the interior of the perimeter of the lip 384, into which the lower or inner end of the mouthpiece core 310 and the lower or inner end of the mouthpiece seal are located. In this embodiment, the body of the seal 380 is longer than the seal in the previous embodiments, and the seal extends completely down the length of the interior surface of the lip 384 to the surface of the recess / indentation in the filter holder 350. Figure 6 As shown in FIG. 12, the lip 384 has a recess or indentation formed in the interior of the perimeter of the lip 384, into which the lower or inner end of the mouthpiece core 310 and the lower or inner end of the mouthpiece seal are located. In this embodiment, the body of the seal 380 is longer than the seal in the previous embodiments, and the seal extends completely down the length of the interior surface of the lip 384 to the surface of the recess / indentation in the filter holder 350.

[0057] As with the first and second embodiments, the pressure recess is formed by the cavity 390 and the chamber 360.

Claims

1. A mouthpiece securing assembly for an inhalation device, comprising: (i) a mouthpiece core having an inlet end and an outlet end, the outlet end distal with respect to the inhalation device and configured to deliver a liquid for inhalation, the inlet end proximal with respect to the inhalation device and configured to receive the liquid for inhalation; (ii) a mouthpiece retainer comprising a retention portion that encircles at least a portion of the outlet end of the mouthpiece core and comprising an end wall having an aperture, such that the end wall retains the mouthpiece core and the aperture allows delivery of the liquid from the outlet end of the mouthpiece core, the retention portion comprising a proximally-facing retainer abutment surface; (iii) a filter retainer proximal with respect to the mouthpiece retainer and defining a chamber between a body of the filter retainer and the mouthpiece core, the chamber in communication with the inlet end of the mouthpiece core to supply the liquid to the mouthpiece core, the filter retainer comprising a chamber portion that encircles at least a proximal portion of the chamber and comprising a first filter retainer abutment surface that faces distally and abuts at least a portion of the retainer abutment surface to define an abutment interface; and (iv) a mouthpiece seal disposed annularly around at least a portion of the mouthpiece core so as to be in sealed contact with the mouthpiece core, wherein the mouthpiece seal has a first end that at least partially abuts the end wall of the mouthpiece retainer, and a second end that is toward the inlet end of the mouthpiece core, wherein the mouthpiece seal extends between the mouthpiece core and the mouthpiece retainer and extends between the mouthpiece core and the filter retainer, such that the mouthpiece seal is in sealed contact with the mouthpiece retainer and the filter retainer and provides a peripheral seal line at the abutment interface; wherein the filter retainer comprises a distally-facing second filter retainer abutment surface, and an annular outer portion of the second end of the mouthpiece seal is in sealed contact with the second filter retainer abutment surface; and wherein an annular inner portion of the second end of the mouthpiece seal is concave, such that the chamber extends into the second end of the mouthpiece seal. The annular inner portion of the mouthpiece seal is concave to include a mouthpiece core-facing surface and a proximally-facing inner surface that intersect at a sharp edge to define a recess that extends circumferentially around at least a portion of the mouthpiece core.

2. The mouthpiece securing assembly of claim 1, wherein, The annular inner portion of the mouthpiece seal is concave to include a mouthpiece core-facing surface and a proximally-facing inner surface that intersect at a rounded edge to define a recess that extends circumferentially around at least a portion of the mouthpiece core.

3. The mouthpiece securing assembly of claim 1, wherein, The annular inner portion of the mouthpiece seal is concave to include a mouthpiece core-facing surface and a proximally-facing inner surface that intersect at a rounded edge to define a recess that extends circumferentially around at least a portion of the mouthpiece core.

4. The mouthpiece securing assembly of claim 1, wherein, The annular inner portion of the mouthpiece seal is concave to include a mouthpiece core-facing surface and a proximal end-facing inner surface that meet at a chamfered edge to define a recess extending circumferentially around at least a portion of the mouthpiece core.

5. An inhalation device comprising the mouthpiece securing assembly of any preceding claim.

6. The inhalation device of claim 5, being a soft mist inhaler (SMI).

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