TECHNICAL FIELD

This invention relates to the nebulisation of liquids. In particular, though not exclusively, this invention relates to a nozzle fixing assembly for a drug delivery device. This invention also relates to an inhalation device comprising the nozzle fixing assembly.

BACKGROUND

Drug delivery devices such as soft mist inhalers (SMIs) can be used to produce an aerosol of droplets for inhalation through the mouth and pharyngeal cavity into the lungs of a patient, for nasal administration, or for spraying the surface of the eye.

In a drug delivery device of this kind, liquid pharmaceutical formulations are typically stored in a reservoir. From there, they are conveyed through a riser tube into a pressure chamber from where they are forced through a nozzle under pressure and atomised. In this way, drug delivery devices such as SMIs are able to nebulise a small amount of a liquid formulation according to the required dosage within a few seconds to produce an aerosol suitable for therapeutic inhalation. Moreover, this can be achieved without requiring the use of a propellant.

The nozzle is typically held in place in the device by a seal and a fixing mechanism/structure. As the device is actuated, liquid formulation is forced through the nozzle under high pressures.

These high pressures are significant enough to extrude seal material through any small gaps in the componentry and are high enough to damage the structure of the nozzle or result in failure of the seal.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. 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 OF THE INVENTION

It is an object of the present invention to provide a nozzle fixing assembly which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice.

It is a further object of the invention to provide an inhalation device comprising a nozzle fixing assembly which goes some way to overcoming the abovementioned disadvantages or which at least provides the public or industry with a useful choice. In a first aspect, the invention may broadly be said to consist in a nozzle fixing assembly for an inhalation device, comprising: a nozzle chip configured to allow a flow of liquid through the nozzle chip from the inlet end to the outlet end; an assembly housing configured to substantially surround the nozzle chip except for at least part of the outlet end, and to hold the nozzle chip in position; a nozzle seal configured to extend around the nozzle chip between the nozzle chip and the assembly housing, to provide a seal between the nozzle chip and the assembly housing; the nozzle seal and assembly housing further configured so that a pressure recess is formed between the nozzle seal and assembly housing so that in use high pressure liquid enters the pressure recess and exerts outwards pressure on the nozzle seal.

In an embodiment, the nozzle seal and assembly housing are configured so that the pressure recess extends across the inlet end, and partly along the side of, the nozzle chip.

In an embodiment, the assembly housing comprises an outer part that surrounds the side wall of the nozzle chip from the outlet end to part way along the nozzle chip, the nozzle holder having an outer end wall that extends beyond and over the outlet end of the nozzle chip.

In an embodiment, the outer end wall extends fully around the outlet end of the nozzle chip, with an aperture substantially at the centre of the of the end wall.

In an embodiment, the end wall is formed so that in cross section it has the form of a conically- shaped recess.

In an embodiment, the nozzle seal extends from substantially the outlet end of the nozzle chip to partway along the nozzle chip between the inlet and outlet ends for a first length, making sealing contact with the side wall of the nozzle chip for a portion of the first length, the nozzle seal shaped to include a cavity formed between the outer surface of the nozzle chip and the inner surface of the nozzle seal, the cavity extending part way up the side of the nozzle chip.

In an embodiment, the cavity extends substantially around the whole of the side of the nozzle chip.

In an embodiment, the cavity has a side wall and an inwards-facing surface, the side wall and surface meeting at a substantially 90° angle circumferentially around the cavity.

In an embodiment, the transition between the side wall and inwards-facing surface is formed as a smooth curve or chamfer.

In an embodiment, the assembly housing is formed from a filter holder and a separate nozzle holder that in combination form the assembly housing.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 shows a cross sectional side view of a nozzle fixing assembly in accordance with a first embodiment of the invention;

Figure 2 shows a close-up of the cross-sectional view of the nozzle fixing assembly shown in Figure 1 ;

Figure 3 shows a perspective view of the nozzle seal shown in the nozzle fixing assembly in Figures 1 and 2;

Figure 4 shows a cross sectional view of a nozzle fixing assembly in accordance with a second embodiment of the invention; and

Figure 5 shows a perspective view of the nozzle seal shown in the nozzle fixing assembly in Figure 4.

DETAILED DESCRIPTION

FIRST EMBODIMENT

A nozzle fixing assembly 100 in accordance with a first embodiment of the invention comprises the following main parts: a nozzle chip or nozzle cap 110; a nozzle holder 120; a nozzle seal 180; a filter holder 150; a filter 140, and; a nut 130. The nozzle fixing assembly 100 is incorporated into an inhalation device 10.

Nozzle Chip

The nozzle chip 110 is generally cuboidal in overall appearance (rectangular in both plan and side view), and has an inlet end 112 and an outlet end 114. When the nozzle fixing assembly 100 is fitted to or incorporated into the inhalation device 10, the inlet end 1 12 faces towards or into the inhalation device 10, with the outlet end 114 facing in the opposite direction. The nozzle chip 110 is configured to allow a flow of liquid through the nozzle chip 110 from the inlet end 112 to the outlet end 114. A “nozzle chip” 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 nozzle chip comprises a filtering structure, comprising one or more microstructured channels that are generally zig-zag shaped (i.e. form a generally zig-zag structure). In this way, the filtering structure advantageously prevents any coarse debris from blocking the microstructured channels at the outlet end. The outlet end of the nozzle chip comprises one or more spray jets. If a nozzle chip is used that has two or more spray jets are present, the geometries of the spray jets can be arranged to cause two or more jets of liquid exiting the spray jets to impinge upon one another (i.e. collide with each other).

Nozzle Holder

The nozzle holder 120 comprises a holder portion 122 that circumferentially surrounds the side wall of the nozzle chip 110, from the outlet end 114 of the nozzle chip 110 to approximately two- thirds of the way along/down the nozzle chip 110 from the inlet end 112 to the outlet end 114. The nozzle holder 120 has an outer end wall 124 that extends from the holder portion 122 beyond and over the outlet end 114 to retain the outlet end 114 of the nozzle chip 110. The end wall 124 extends circumferentially around the holder portion 122. The end wall is formed such that there is an aperture 126 in the centre of the end wall 124 at the outer face of the nozzle chip 110 that forms the outlet end 114. This allows the delivery of liquid from the outlet end 114 of the nozzle chip 110. The end wall 124 is formed so that in cross section it has the form of a conically-shaped recess 128, which extends from the aperture 126, the narrow end of the cone at the outer face of the nozzle chip 110 that forms the outlet end 114. The inner end of the holder portion 122 comprises an abutment surface 129 which faces towards the inhalation device 10.

Filter Holder

The filter holder 150 is formed so that in use it circumferentially surrounds the remaining third of the side wall of the nozzle chip 110, from the abutment surface 129. The body of the filter holder 150 extends from the abutment surface 129 towards the inhalation device 10. The body is formed so that it partly overlaps with and encloses the nozzle chip 110 at the inlet end 112, with the gap or chamber 160 between the two forming part of a pressure recess as described below.

The filter holder 150 is configured to hold filter 140 in position close to the inlet end 112 of the nozzle chip 110. In this embodiment, the filter 140 and nozzle chip 110 are both cylindrical, and have a common central axis. The filter 140 is accommodated by a recess 151 in the filter holder 150, the recess open at the inhalation device end to allow the filter to be inserted or removed, the filter holder 150 having a channel 156 that passes through the centre of the filter holder 150 at the central axis, to allow fluids to pass from the filter 140 to the nozzle chip 110. The filter holder 150 and nozzle holder 120 are mutually configured so that in use a chamber 160 is formed between the filter holder 150 and the inlet end 122 of the nozzle chip 110 - that is, the filter holder 150 is not directly in contact with the nozzle chip 100 at the inlet end 112.

The filter holder 150 and nozzle holder 120 are further mutually configured so that the chamber 160 surrounds the inlet end 112 and extends annularly around the nozzle chip 110 into the cavity 190 that extends approximately halfway along the nozzle chip 110 between its inlet and outlet ends 112, 114. The cavity 190 and chamber 160 together form a

It can be seen that the filter holder 150 and the nozzle holder 120 in combination form an assembly housing. In the embodiments described and shown, these elements are separate and discrete (and connected in use). However, an assembly housing could in alternative embodiments be formed as a one-piece item, or from other variations of multiple pieces, as required.

A step or recess 184 is formed in the side of the filter holder on the inside, as described in detail below, in the filter sub-section.

Filter

As described above, the filter 140 locates into the recess 151 in use. The filter 140 has an inlet end 142 at that end towards the inhalation device 10, and an outlet end 144 at the opposite end, adjacent to the nozzle chip 110. The channel 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 a conduit 12 in the inhalation device 10.

As shown in figure 1 , the filter holder 150 is configured to have an abutment surface 152 which in use is in contact with the nozzle holder abutment surface 129, surface 152 and surface 129 defining an abutting interface 170 between the first filter holder abutment surface 152 and the nozzle holder abutment surface 129. In this way, the nozzle chip 110 and chamber 160 are enclosed between the nozzle holder 120 and filter holder 150.

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

Nozzle Seal

The nozzle seal 180 in use extends around the nozzle chip 110 between the nozzle chip 110, the nozzle holder 120, and part of the filter holder 150. The nozzle seal 180 extends around the nozzle chip 110, and extends from the outlet end 114 of the nozzle chip 110 to about halfway along the nozzle chip 110 between the inlet and outlet ends 112, 114. The nozzle seal 180 makes sealing contact with the side wall of the nozzle chip 110. The nozzle seal 180 has a first end 182 which faces distally or away from the inhalation device 10, the first end 182 abutting the inside surface of the end wall 124 of the nozzle holder 120. The second end of the nozzle seal 180 is at the opposite end facing towards the inhalation device 10 in use.

As shown in figure 1 , the filter holder 150 is shaped so as to form a step or recess 184, the recess 184 radially inwards on the filter holder at that end away from the inhalation device 10 in use. The surface of the recess 184 facing away from the inhalation device 10 forms a second filter holder abutment surface 154. The nozzle seal 180 is sized and shaped so that when fitted it extends into the recess 184 and contacts the abutment surface 154.

The nozzle seal 180 extends between the nozzle chip 110 and the holder portion 122 and between the nozzle chip 110 and the filter holder 150 such that the nozzle seal 180 makes sealing contact with the holder portion 122 and filter holder 150 and provides a perimetral line of sealing at the abutting interface 170 between the first filter holder abutment surface 152 and the nozzle holder abutment surface 129.

The nozzle seal 180 is also shaped to include a cavity 190, the cavity 190 formed so that the chamber 160 extends partly (about halfway) up the side of the nozzle chip 110.

Figure 3 provides a perspective view of the nozzle seal 180, looking from the end that is towards the inhalation device 10 in use. This view shows detail of the cavity 190 at the inner end, towards the inhalation device 10. The cavity 190 has a side wall 186, and a surface 187 that in use faces towards the inhalation device 10. The side wall 186 and surface 187 meet at a 90° angle to form a sharp edge 188 which extends circumferentially around the nozzle seal cavity 190. A rectangular slot 189 is formed in the nozzle seal for accommodating the nozzle chip 1 10.

Nut

The nut 130 is configured for fixing the nozzle holder 110 in place on the inhalation device 10. As shown in figure 1 , the nut 130 encloses the nozzle holder 120 and filter holder 150, except for an opening around the conically-shaped recess 128.

In use, force is exerted on the nozzle seal 180 by liquid in the chamber 160 as shown by the arrows on figure 2. The liquid exerts outwards pressure on the nozzle seal 180 - that is, in this case ‘outwards’ indicates that pressure is exerted on the nozzle seal 180 by the high pressure liquid in the cavity 190 on the inner surface of the seal (facing into the cavity 190). This pressure enhances the seal between nozzle seal 180 and the nozzle holder 120 and between the nozzle seal 180 and the filter holder 150. This improves the radial sealing between the nozzle holder 120 and nozzle seal 180 and between the filter holder 150 and nozzle seal 180 and reduces any leakage of the liquid from the nozzle fixing assembly 100.

SECOND EMBODIMENT Figure 4 illustrates a nozzle fixing assembly 200 in accordance with a second embodiment of the invention.

The nozzle fixing assembly 200 has generally the same structure as the first embodiment of nozzle fixing assembly 100, and similar numbering is used for similar elements - e.g: nozzle chip 110, 210; filter 140, 240, etc.

In this embodiment, the recessed portion - cavity 290 - of the nozzle seal 280 is formed with a smooth curve or chamfer, rather than as a 90-degree angle to form the sharp edge 188 as in the first embodiment. That is, the transition between the side wall and the inwards-facing surface of the cavity is formed as a smooth curve or chamfer. As for the first embodiment, the pressure recess is formed from cavity 290 and chamber 260.

Figure 4 has been marked up with arrows which show the direction of the force exerting on the nozzle seal 280 by high pressure liquid in the cavity 290 when the inhalation device 10 is in use. The chamfered edge 288 of the cavity 290 can help to provide a more distributed pressure profile through the nozzle seal 280.

Figure 5 provides a perspective view of the nozzle seal 280, from the same angle as for figure 3. As mentioned above, the annularly inner portion of the second end 284 of the nozzle seal 280 is recessed to define a nozzle-facing surface 286 and recessed inner surface 287 that faces towards the inhalation device 10 in use. The nozzle-facing surface 286 and inner surface 287 meet to form a radiused edge 288 and define a cavity 290 which extends circumferentially around the nozzle chip 210. The proximal facing inner surface 287 of the nozzle seal 280 also comprises a rectangular slot 289 for accommodating the nozzle chip 210.

THIRD EMBODIMENT

A third embodiment of nozzle fixing assembly 300 is shown in figure 6. The nozzle fixing assembly 300 has generally the same structure as the first and second embodiments described above and shown in figures 1 to 5. Similar numbering is used for similar elements - e.g: nozzle chip 110, 210, 310; filter 140, 240, 340, etc.

In this embodiment, the filter holder does not have a step or recess such as step 184 in the first embodiment. The equivalent in this embodiment is the parapet or lip 384. The filter holder 350 is formed so that parapet or lip 384 runs 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, so that an indent or recess is formed inside the perimeter of the lip 384, into which the lower or inner end of the nozzle chip 310 and the lower or inner end of the nozzle seal locate.

In this embodiment, the body of the seal 380 is longer than the seals of the previous embodiments, and extends fully down the length of the inside surface of the lip 384 to the surface of the indent/recess in the filter holder 350. As shown in figure 6, the recessed portion 390 of the nozzle seal 380 has a side wall and surface that meet at a 90° angle to form a sharp edge 388 which extends circumferentially around the nozzle seal recess, as for the first embodiment. However, the recessed portion could be chamfered, as for the second embodiment. As for the first and second embodiments, the pressure recess is formed from cavity 390 and chamber 360.