GB2279879A

GB2279879A - Medicament inhalers

Info

Publication number: GB2279879A
Application number: GB9314598A
Authority: GB
Inventors: David John Howlett
Original assignee: Bespak PLC
Current assignee: Consort Medical PLC
Priority date: 1993-07-14
Filing date: 1993-07-14
Publication date: 1995-01-18
Anticipated expiration: 2013-07-14
Also published as: GB2279879B; GB9314598D0

Abstract

An inhaler for medicament comprises a housing (11) adapted to receive a pressurised dispensing container (12) of medicament. A mouth piece (14) for insertion into the mouth of a user of the inhaler is connected by duct means to an outlet (13) of the container. Air inlet means are provided for allowing air into the inhaler when a user applies suction to the mouth piece. The air inlet means (23) are provided at a location axially between the air outlet for the duct means and the mouth piece and passage means are provided connecting the inlet to a location adjacent the outlet of the duct means. The arrangement is such that, in use, when a user inhales through the mouth piece an airflow is created from the inlet to the mouth piece and the airflow has a component directed away from the mouth piece towards the outlet of duct means. <IMAGE>

Description

MEDICAMENT INHALERS The invention relates to an inhaler for medicament and particularly to an inhaler for transferring to a patient a metered dose of medicament contained in a pressurised dispensing container.

In known metered dose inhalers, the aerosol stream from a pressurised dispensing container is fired towards a patient or user of the inhaler into an air flow travelling in the same direction. In known devices, a user inhales through a mouth piece of the inhaler and creates an air flow through the container from air inlet holes which are generally at a part of the inhaler well spaced from the mouth piece. The medicament is then released into this air flow at a point between the air inlet holes and the mouth piece so that it is travelling in the same direction as the air flow. Typically in such devices, there is no restriction in the air flow between the air inlet holes and the mouth piece. Because of this, a substantial air flow may be created by a user of the device and, because the medicament is fired into the air flow in the same direction as the air flow, the effect is that particles of medicament can attain quite substantial velocities. As inhalers of this type are normally designed to be as small as practical for the convenience of users, the distance between the point at which the medicament is fired into the air flow and the patients mouth is usually quite small so that there is little distance to reduce the inertia of the particles of medicament with the result that the particles may impact in the oro-pharynx of a user with quite high velocity.

This can be a problem with some medicaments.

In an effort to overcome this problem, devices have been produced in which the medicament is fired into a holding volume which allows the velocity of the medicament to be reduced and also allows some evaporation to occur.

However, these devices with a holding volume tend to be of significantly larger size than the standard metered dose inhalers and therefore less convenient and attractive to users.

The present invention seeks to provide an inhaler which allows delivery of medicament to a user at reduced velocity without significantly increasing the size of the inhaler.

The invention provides an inhaler for medicament comprising a housing adapted to receive a pressurised dispensing container of medicament, a mouth piece for insertion into the mouth of a user of the inhaler, duct means connecting an outlet of the container with the mouth piece and air inlet means for allowing air into the inhaler when a user applies suction to the mouth piece in which the air inlet means are provided at a location axially between the air outlet of the duct means and the mouth piece, and passage means are provided connecting the inlet means to a location adjacent the outlet of the duct means so that, in use, when a user inhales through the mouth piece, an air flow is created from the inlet means to the mouth piece, the air flow having a component directed away from the mouth piece towards the outlet of the duct means.

Preferably the passage means includes a restriction to limit the air flow from the inlet means to the mouth piece.

The inlet means may comprise air inlet holes around the periphery of a portion of the inhaler adjacent to the mouth piece and the housing may include a wall portion in which the duct means is formed, the wall portion providing an air barrier between the housing and the mouth piece.

Further features and advantages of the invention will be apparent from the following description, by way of example, of a preferred embodiment of the invention, the description being read with reference to the accompanying drawing which shows a longitudinal cross-section through an actuator according to the invention.

Referring to the drawing, an actuator or inhaler 10 for a medicament comprises a housing 11 for receiving a pressurised dispensing container 12 of medicament, a mouth piece 14 for insertion into the mouth of a user of the actuator and a cover 15 for the mouth piece.

The container housing 11 is generally cylindrical and open at its upper end. A lower wall 17 of the housing 11 includes a thickened portion defining a seat 18 for receiving the tubular valve stem 13 of the container 12.

The seat 18 communicates via a duct ending in an orifice 19 with the mouth piece 14.

The mouth piece 14 which may be generally circular or shaped to fit the mouth is at an angle somewhat in excess of 900 to the axis of the container housing 11. This angle is designed to present the mouth piece at a comfortable angle to the user of the device when the actuator is held in a hand of the user.

The mouth piece 14 is connected to the housing 11 through a generally frusto-conical wall portion 20. The wall portion 20 includes inner and outer walls 21, 22, the inner wall 21 being an extension of the mouth piece 14 and the outer wall 22 forming with the inner wall a restricted air flow passage from inlet air holes 23 provided in the outer wall around the periphery of the mouth piece to a restricted air inlet 25 adjacent a neck portion 24 of the device.

The cover 15 of the device which fits over the open mouth piece 14 is connected by a flexible hinge portion 27 to a cover attachment 28 which fits in the lower part of the housing 11 to attach the cover to the housing. All the components of the actuator 10 may be plastics mouldings.

It will be appreciated that the lower wall formation 17 of housing 11 forms a barrier between the open end of the housing 11 and the mouth piece 14 so that there is no air flow passage from around the container 12, or the left side of the housing 11 (as viewed in the drawing), to the mouth piece 14.

In use of the actuator 10, a patient or user holds the actuator usually in one hand and applies his mouth to the mouth piece 14. The user then inhales through the mouth piece 14 and this creates an air flow from inlet air holes 23 via the restricted air inlet 25 to the mouth piece 14.

It will be appreciated that the inlet air holes 23 are arranged downstream of the orifices 19 relative to the mouth piece 14, that is to say the inlet air holes 23 are axially closer to the mouth piece 14 than the neck portion 24 and orifice 19. This ensures that when a user inhales through the mouth piece 14, the air flow is not directly from a position upstream of the orifice 19 to the mouth piece 14 but has at least a component of reverse flow towards the orifice 19. The rate of air flow is also controlled by the restricted air inlet 25. The effect of the restriction and the reverse air flow is to create a turbulent air flow in the neck portion 24.

After the user has started inhaling through the mouth piece 14, the container 12 is depressed downwardly on to its stem 13 as shown in the drawing to release a dose of medicament from the container. The dose of medicament is projected by the pressure in the container 12 through the orifice 19 and then mixes with the turbulent air flow in the neck portion 24 and thence is inhaled by the user.

The reverse flow component of air flow and the turbulence thereby created ensure that the velocity of medicament particles is relatively low when they enter the oro-pharynx region of the patient.

When not in use, the cover 15 is placed in the position shown in the drawing and when the actuator is to be used, the cover is removed by hinging it away from the mouth piece 14.

The invention is not restricted to the embodiment described above and various modifications may be made within the scope of the appended claims.

Claims

CLAINS:

1. An inhaler for medicament comprising a housing adapted to receive a pressurised dispensing container of medicament, a mouth piece for insertion into the mouth of a user of the inhaler, duct means connecting an outlet of the container with the mouth piece and air inlet means for allowing air into the inhaler when a user applies suction to the mouth piece in which the air inlet means are provide at a location axially between the air outlet of the duct means and the mouth piece, and passage means are provided connecting the inlet means to a location adjacent the outlet of the duct means so that, in use, when a user inhales through the mouth piece, an air flow is created from the inlet means to the mouth piece, the air flow having a component directed away from the mouth piece towards the outlet of the duct means.

2. A inhaler as claimed in claim 1 in which the passage means includes a restriction to limit the air flow from the inlet means to the mouth piece.

3. An inhaler as claimed in claim 1 or claim 2 in which the inlet means comprise air inlet holes around the periphery of a portion of the inhaler adjacent to the mouth piece.

4. An inhaler as claimed in any one of the preceding claims in which the housing includes a wall portion in which the duct means is formed, the wall portion providing an air barrier between the housing and the mouth piece.