INHALER SPACER

Abstract

The invention relates to an inhaler spacer (1) comprising an inlet (2) for connection to an inhaler and an outlet (4) through which a user can inhale. The inhaler spacer (1) comprises a duct (6) extending between the inlet (2) and the outlet (4). The duct (6) is defined by a wall (8) which extends around a first axis (10) and comprises a diffuser portion (12) extending along the first axis away from the inlet. The wall (8) of the duct (6) in at least apart of the diffuser portion curves outwardly away from the first axis with increasing distance away from the inlet such that the cross sectional area of the diffuser portion perpendicular to the first axis increases with increased distance from the inlet along the first axis.

Claims

1. An inhaler spacer (1) comprising an inlet (2) for connection to an inhaler and an outlet (4) through which a user can inhale, the inhaler spacer (1) comprising a duct (6) extending between the inlet (2) and the outlet (4), the duct (6) being defined by a wall (8) which extends around a first axis (10) and comprising a diffuser portion (12) extending along the first axis (10) away from the inlet (2), the wall of the duct (6) in at least a part of the diffuser portion (12) curving outwardly away from the first axis (10) with increasing distance away from the inlet (2) such that the cross sectional area of the diffuser portion (12) perpendicular to the first axis (10) increases with increased distance from the inlet (2) along the first axis (10).

2. The inhaler spacer (1) as claimed in claim 1, in which the outward curving of the duct wall (8) in the diffuser portion (12) is a substantially continuous outward curve.

3. The inhaler spacer (1) as claimed in claim 1 or claim 2, in which the diffuser portion (12) has a substantially circular cross section perpendicular to the first axis (10) and the radius of the cross section increases with increased distance from the inlet (2) along the first axis (10) within the outwardly curving portion.

4. The inhaler spacer (1) as claimed in claim 3, in which the rate of increase of radius increases with increased distance from the inlet (2).

5. The inhaler spacer (1) as claimed in any preceding claim, in which the wall (8) of the diffuser portion (12) proximal the inlet (2) extends at an angle of less than 5 degrees away from the first axis (10).

6. The inhaler spacer (1) as claimed in claim 5, in which the wall (8) of the diffuser portion (12) proximal the inlet extends substantially parallel with the first axis (10).

7. The inhaler spacer (1) as claimed in any preceding claim, in which the wall (8) of the diffuser portion (12) distal from the inlet (2) extends at an angle of more than 15 degrees away from the first axis (10).

8. The inhaler spacer (1) as claimed in claim 7, in which the wall of the diffuser portion (12) distal from the inlet (2) extends at an angle greater than 18 degrees away from the first axis (10).

9. The inhaler spacer (1) as claimed in any of claims 1 to 6, in which the wall of the duct (6) in at least part of the diffuser portion (12) curves inwardly towards the first axis (10) with increasing distance away from the inlet (2), the outwardly curving portion being arranged between the inlet (2) and the inwardly curving portion (28) such that, in the diffuser portion (12) having inwardly curving walls, the cross sectional area of the diffuser portion (12) perpendicular to the first axis (10) increases with increased distance from the inlet (2) along the first axis (10).

10. The inhaler spacer (1) as claimed in claim 9, in which the outward and then inward curve of the duct wall (8) in the diffuser portion (12) forms a substantially continuous curve.

11. The inhaler spacer (1) as claimed in any preceding claim, in which the diffuser portion (12) is substantially rotationally symmetrical about the first axis (10).

12. The inhaler spacer (1) as claimed in any preceding claim, in which the diffuser portion (12) extends between 7 cm and 12 cm along the first axis (10).

13. The inhaler spacer (1) as claimed in any preceding claim, in which the minimum cross sectional area of the diffuser portion (12) perpendicular to the first axis is between 5 cm.sup.2 and 9 cm.sup.2.

14. The inhaler spacer (1) as claimed in any preceding claim, in which the maximum cross sectional area of the diffuser portion (12) perpendicular to the first axis is between 20 cm.sup.2 and 35 cm.sup.2.

15. The inhaler spacer (1) as claimed in any preceding claim, in which the inhaler spacer (1) includes a reducer portion (24) between the diffuser portion (12) and the outlet, the wall of the duct (6) in the reducer portion (24) extending towards the first axis (10) with increasing distance away from the inlet such that the cross sectional area of the reducer portion (24) perpendicular to the first axis (10) decreases with increased distance from the inlet (16) along the first axis (10).

16. The inhaler spacer (1) as claimed in claim 15, in which the wall (8) of the duct (6) in the reducer portion (24) is substantially conical.

17. The inhaler spacer (1) claimed in claim 15, in which the wall (8) of the duct (6) in at least a part of the reducer portion (24) is continuously curved such that the wall (8) curves inwardly from a wide end of the reducer portion (24) and outwardly near a narrow end of the reducer portion (24).

18. The inhaler spacer (1) as claimed in any of claims 15 to 17, in which the inhaler spacer (1) includes a transition portion (20) between the diffuser portion (12) and the reducer portion (24), the transition portion (20) comprising a releasable coupling allowing the diffuser portion (12) to be separated from the reducer portion (24).

19. The inhaler spacer (1) as claimed in claim 18, in which the releasable coupling comprises a bayonet type releasable coupling.

20. The inhaler spacer (1) as claimed in any preceding claim, in which the outlet (4) comprises a protruding mouthpiece.

21. The inhaler spacer (1) as claimed in claim 20, in which the spacer includes a movable mouthpiece cover (32) which is coupled to the inhaler spacer (1) and can be moved between a closed position in which mouthpiece cover (32) substantially covers the mouthpiece and an open position in which the mouthpiece is exposed for use.

22. The inhaler spacer (1) as claimed in any preceding claim, in which a one way valve (54) is provided adjacent the outlet (52) so that a user may be hindered from exhaling into the spacer through the outlet (52).

23. The inhaler spacer (1) as claimed in any preceding claim, in which the inlet (2) is shaped to receive and retain a mouthpiece of an actuator of a pressurised metered dose inhaler.

24. A method of preparing a medicament dose for use, the method comprising the steps of: a) providing a pressurised metered dose inhaler (38) having an inhaler mouthpiece; b) providing an inhaler spacer (1) as claimed in any of the preceding claims; c) fitting the inhaler mouthpiece to the inlet of the spacer (1); and d) dispensing a dose of medicament into the spacer (1) from the pressurised metered dose inhaler.

25. A method of delivering a medicament to a patient comprising the steps of preparing a medicament dose for use as claimed in claim 24 and causing the patient to inhale through the outlet (4) of the inhaler spacer (1).

26. An entry-section for coupling to an exit section to form an inhaler spacer (1), the entry section including a diffuser portion (12) and the exit section including a reducer portion (24), the inhaler spacer (1) as claimed in claim 18 or 19 and the entry section including an inlet (2) and the wall of the diffuser portion (12) curving outwardly away from the first axis (10) with increasing distance away from the inlet (2) such that the cross-sectional area of the diffuser portion (12) perpendicular to the first axis (10) increases with increased distance from the inlet (2) along the first axis (10).

27. An inhaler spacer (1) substantially as described herein, with reference to, or as shown in, the accompanying Figures.

Description

[0044] FIG. 1 shows a cross section through a first inhaler spacer;

[0045] FIG. 2 shows a cross section through a second inhaler spacer;

[0046] FIG. 3 shows a cross section through the inhaler spacer of FIG. 2 coupled to a pMDI actuator; and

[0047] FIGS. 4 and 5 show an inhaler spacer separated into an entry section (FIG. 5) and an exit section (FIG. 4).

[0048] FIG. 1 shows an inhaler spacer 1 comprising an inlet 2 for connection to an inhaler, particularly a pMDI (shown in FIG. 3) and an outlet 4 through which a user can inhale. The inhaler spacer 1 comprises a duct 6 extending between the inlet 2 and the outlet 4. The duct 6 is defined by a wall 8 which extends around a first axis 10 and comprises a diffuser portion 12 extending along the first axis away from the inlet 2. The wall 8 of the duct 6 in at least a part 14 of the diffuser portion 12 curves outwardly away from the first axis 10 with increasing distance away from the inlet 2 such that the cross sectional area of the diffuser portion 12 perpendicular to the first axis 10 increases with increased distance from the inlet 2 along the first axis 10.

[0049] The inlet 2 is located in an inlet portion 16 and the outlet 4 in an outlet portion 18. The diffuser portion 12 forms part of an entry section 26 comprising the inlet portion 16, diffuser portion 12 and a part of a transition portion 20. The transition portion 20 couples the entry section 26 to an exit section 22 which comprises the outlet portion 18 and a reducer portion 24 and a part of the transition portion 20. The inhaler spacer 1 is substantially circular in cross section perpendicular to the first axis 10, although it should be noted that the inlet portion 16, outlet portion 18 and potentially the transition portion 20 may not be exactly circular as they are intended to fit with other elements.

[0050] Marked on FIG. 1 are some lines a, b and c indicating the direction in which the duct wall 8 extends at particular locations 30a, 30b and 30c in the diffuser portion 12. The lines a, b and c share a letter with their respective locations 30a, 30b and 30c. It can be seen that at an end of the diffusion portion 12 proximal the inlet portion 16 the wall extends substantially parallel with the first axis 10 (30a). As the duct extends along the first axis the angular offset from the first axis 10 of the duct wall 8 within the part 14 of the diffuser portion 12 increases (30b and 30c).

[0051] The reducer portion 24 is substantially frustoconical in shape and reduces the diameter of the duct 6 from the transition portion 20 to the outlet portion 18 as the duct 6 extends along the first axis 10.

[0052] The Fine Particle Dose (FPD) delivered by an inhaler spacer following the design of the inhaler spacer 1 of FIG. 1 was tested and compared to known inhaler spacers. The FPD was defined to be the dose of drug having an aerodynamic particle size below 5 m (allowing inhalation into the lungs) that was drawn from the inhaler spacer as tested by Cascade Impactor. The new inhaler spacer had a diffuser portion 12 that was about 9 cm long and varied from having a wall that was substantially parallel with the first axis 10 adjacent the inlet portion 16 to extending away from the first axis 10 at an angle of about 20 degrees at the end distal from the inlet portion 16. This resulted in a diameter increase over the diffuser portion from about 3 cm to about 6.3 cm.

[0053] It can be seen from the table that the new inhaler spacer 1 of FIG. 1 achieved a significantly higher FPD than the prior art. This means that the present invention can provide inhaler spacers that have significantly improved FPDs for their size, or the present invention can allow a smaller physical size for a FPD comparable to the prior art inhaler spacers.

[0054] FIG. 2 shows an inhaler spacer 101 having a FPD comparable to the prior art inhaler spacers, but having a reduced physical size. Features substantially identical to those of inhaler spacer 1 of FIG. 1 are marked with the same reference numeral. Features that are functionally similar to those of the inhaler spacer 1 of FIG. 1 are marked with the same reference numeral incremented by 100.

[0055] In this case, a key difference between the inhaler spacer 101 and the inhaler spacer 1 is that the part 114 of the diffuser portion 112 that has an outward curve does not occupy substantially the entire diffuser portion 112 of the intake section 126. There is an inwardly curving part 28 of the diffuser portion 112 between the outwardly curving part 114 and the transition portion 20. In the inwardly curving portion the wall 8 of the duct 6 curves inwardly towards the first axis 10 with increasing distance away from the inlet 2. Since this follows the outwardly curving section 14, the inwardly curving section returns the wall to a substantially parallel with the first axis 10. This means that in the inwardly curving section 28 the cross sectional area of the diffuser portion 112 perpendicular to the first axis 10 still increases, or at least does not decrease, with increased distance from the inlet 2 along the first axis 10. The dual curving parts, outward 114 and then inward 28, results in a continuous curve that increases the diameter of the duct, but does not introduce any significant discontinuities, such as sharp corners, into the duct 6.

[0056] The reducer portion 124 has a similar continuously curving profile with an initial inward curve moving away from the transition portion 20 and then an outward curve approaching the outlet portion 18 such that the diameter of the duct is reduced without introducing any significant discontinuities, such as sharp corners, into the duct 6.

[0057] Marked on FIG. 2 are some lines d, e, f, g and h indicating the direction in which the duct wall 8 extends at particular locations 30d, 30e, 30f, 30g and 30h in the diffuser portion 112. The lines d, e, f, g and h share a letter with their respective locations 30d, 30e, 30f, 30g and 30h. It can be seen that at an end of the diffusion portion 112 proximal the inlet portion 16 the wall extends substantially parallel with the first axis 10 (30d). As the duct extends along the first axis the angular offset from the first axis 10 of the duct wall 8 within the part 114 of the diffuser portion 112 increases (30e) to a maximum (30f). The wall 8 then curves inwardly in the part 28 of the diffuser portion 112 such that the angular offset from the first axis is reduced from the maximum (30g) and returns to substantially parallel (30h).

[0058] The inhaler spacer 101 also includes a movable mouthpiece cover 32 coupled to the spacer by a tether 34. The mouthpiece cover 32 is adapted to be moved between a closed position in which mouthpiece cover 32 substantially covers the outlet 104 (shown in FIG. 3), in this case a mouthpiece 36 (shown in FIG. 3) and an open position in which the mouthpiece 36 is exposed for use.

[0059] FIG. 3 shows the inhaler spacer 101 of FIG. 2 coupled to a pMDI inhaler 38 for use by a user. The pMDI inhaler 38 comprises an actuator 40 and a pressurised canister 42 containing a medicament formulation. The canister 42 includes a valve 44 and valve stem 46 and is operable to dispense under pressure a metered dose medicament formulation through the valve stem 46 when the valve stem 46 is pressed into the valve 44

[0060] The actuator 40 comprises a body 48 which houses an actuator block 50 into which the valve stem 46 is fitted. The actuator block 50 includes a conduit to conduct medicament emitted from the valve stem 46 to an outlet 52 and thereby aerosolise the medicament formulation for inhalation.

[0061] The outlet portion 18 (shown in FIG. 2) includes a valve, in this case a butterfly valve 54 which hinders a user from exhaling into the inhaler spacer 101. The outlet portion 18 in this case is in the form of a protruding mouthpiece 36 intended to facilitate a user forming a seal around the outlet 104 with their lips during use.

[0062] The results of the comparative tests are presented in Table 1 below:

Fine Particle Dose (FPD) by Cascade Impactor Using Different Inhaler Spacers

[0063] (Using Fluticasone Propionate Metered Dose Inhaler110 mcg/dose)

TABLE-US-00001 TABLE 1 Spacer Used FPD (mcg) out of 110 mcg Zerostat - VT 73 Aerochamber 58 Able Disposable Spacer 35 Inhaler Spacer of FIG. 1 94 Inhaler Spacer of FIG. 2 61

[0064] Table 2 below provides comparative FPD and size data from those tests for various inhaler spacers. In particular, data is included in Table 2 for a reduced size version of the Zerostat VT (the Zerostat VT Small) and data for the inhaler spacers of FIGS. 1 and 2.

TABLE-US-00002 TABLE 2 Spacer Volume Length Diameter FPD Zerostat VT 280 ml 175 mm 75 mm 73 mcg Zerostat VT Small 240 ml 145 mm 75 mm 62 mcg Aerochamber 150 ml 150 mm 50 mm 58 mcg Inhaler Spacer of FIG. 1 240 ml 175 mm 65 mm 94 mcg Inhaler Spacer of FIG. 2 160 ml 124 mm 63 mm 61 mcg

[0065] It can be seen that the FPD for the Zerostat VT Small is about 11 mcg lower than for the full sized version and this is as a result of shortening the inhaler spacer by about 30 mm. By comparison, the Inhaler spacer of FIG. 2 is a further about 20 mm shorter and has a smaller diameter than the Zerostat VT Small, but has a substantially similar FPD.

[0066] The tables above demonstrate that, using the present invention, it is possible to create an inhaler spacer having an enhanced FPD for a particular length when compared with prior designs, see for example the comparison between Zerostat VT and the Inhaler Spacer of FIG. 1. The tables also shows that it is possible to create a short inhaler spacer, for example one of less than 125 mm in length, which has an acceptably high FPD.

[0067] FIGS. 4 and 5 show the entry section 126 (FIG. 5) and exit section 122 (FIG. 4) of the inhaler spacer 101 separated from one another using the releasable coupling in the transition section 20. In this case the releasable coupling is provided by a bayonet style coupling comprising one or more protrusions 56 on one part which engage in one or more shaped recesses 58 in the other part. In this inhaler spacer the protrusions 56 are carried by the exit section 122 and the recesses are carried by the entry section 126, although it could be the other way around, or possibly a combination of the two.