Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1998-05-08
2003-12-02
Lo, Weilun (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
Reexamination Certificate
active
06655380
ABSTRACT:
The present invention relates to a powder inhaler for administering powder by inhalation.
A number of powder inhalers are known which use different systems for introducing a dose of powder into an air stream. Typically, the powder is inhaled into the lungs of a patient in order to treat, for example, asthma.
One such powder inhaler is disclosed in EP-A-0237507. This inhaler comprises an inhalation channel and a mouthpiece comprising an air chamber and an outlet nozzle, which together define a flow path through which a stream of air is drawn during inhalation by a user. This inhaler further comprises means for introducing powder into the inhalation channel. During inhalation, air is first drawn into and through the inhalation channel so as to pick up powder. The stream of air containing powder is then drawn through the air chamber and out of the outlet nozzle of the mouthpiece.
FIG. 1
illustrates such a powder inhaler. The inhaler comprises a mouthpiece
2
comprising an outlet nozzle
4
, an inhaler body
6
and a rotatable grip portion
8
for operating a dosing mechanism for providing doses of powder for inhalation. The inhaler body
6
is provided with an opening
10
which is filled with a window
12
through which an indicating wheel
42
is visible so as to provide an indication as,to the usage of the inhaler.
FIG. 2
illustrates in exploded view component parts disposed within and to the inhaler body
6
. The inhaler body
6
is capped with a divider
14
which is fixed thereto. For aesthetic reasons the inhaler body
6
is an opaque moulding. The divider
14
is a transparent moulding which has a depending tongue
15
, a part of which forms the window
12
.
Within the inhaler body
6
are housed the component parts of the dosing mechanism. These component parts include a dosing unit
16
which comprises a member
17
having a planar surface in which a plurality of dosing means
18
are provided and a shaft
20
which extends axially from the centre of the member
17
, an inhalation unit
22
which comprises an inhalation channel
24
and a storage unit
26
which comprises a storage chamber
28
for storing powder. The above-mentioned component parts of the dosing mechanism are assembled by passing the inhalation channel
24
through an opening
30
in the storage unit
26
and passing the shaft
20
through central openings
32
,
34
in the inhalation unit
22
and the storage unit
26
respectively. When so assembled, the upper ends of the inhalation channel
24
and the storage chamber
28
pass respectively through first and second openings
36
,
38
in the divider
14
. In this way, the inhalation unit
22
and the storage unit
26
are fixed in position in relation to one another and the dosing unit
16
can be rotated relative thereto.
In this inhaler the storage unit
28
is open at the bottom such that in use powder is provided to the dosing unit
16
under the action of gravity and the inhalation unit
22
further comprises scrapers
40
which are resiliently biased against the surface of the member
17
in which the dosing means
18
are provided. In this way, as the dosing unit
16
is rotated, the dosing means
18
, which in this inhaler comprise a plurality of through holes, are filled with powder by the scrapers
40
. Powder is prevented from passing through the dosing means
18
by a plate (not illustrated) which is disposed beneath the dosing unit
16
.
As illustrated in
FIG. 2
, the divider
14
further comprises supporting means
41
for rotatably supporting an indicating wheel
42
. The indicating wheel
42
has a plurality of teeth
44
disposed around the periphery thereof which engage with a spiral groove or protrusion
46
on the end face of the shaft
20
. The supporting means
41
is configured to align the indicating wheel
42
such that a part of the periphery thereof is disposed adjacent the inner surface of the window
12
. In use, as the dosing unit
16
is rotated, the spiral groove or protrusion
46
engages with one or more of the teeth
44
on the indicating wheel
42
so as to rotate the same. In this way, by providing a coloured marking on the periphery of the indicating wheel
42
, it is possible to provide the user with a visible indication at the window
12
as to the usage of the inhaler.
As illustrated in
FIG. 4
, the mouthpiece
2
is fixed to the divider
14
. The mouthpiece
2
comprises first and second parts
48
,
50
, the first part
48
being the part which is gripped by the lips of a user and the second part
50
being an insert fitted within the first part
48
. The second part
50
comprises a tubular section
52
, which includes one or more spirally or helically shaped projections
54
that act to deflect the air drawn therethrough and thereby deagglomerate any larger particles of entrained powder, and a substantially radially-directed flange
56
, which provides a surface that together with upper surface of the divider
14
defines an air chamber
58
that is in fluid communication with the inhalation channel
24
through which air containing powder is drawn on inhalation by a user.
In use, as described hereinabove, powder is transferred from the storage chamber
28
to one of the dosing means
18
, and, with rotation of the dosing unit
16
, the one dosing means
18
provides a dose of powder to the inhalation channel
24
. In this inhaler the dosing unit
16
is rotated by rotating the grip portion
8
in the counter-clockwise sense between first and second angularly-spaced positions. For this purpose the dosing unit
16
comprises wedge-shaped elements
60
disposed around the periphery of the member
17
and the grip portion
8
comprises a resilient member (not illustrated) which is configured to engage with an axially-directed surface
60
a
of a respective one of the wedge-shaped elements
60
so as to rotate the dosing unit
16
by pushing the respective wedge-shaped element
60
. On rotation of the grip portion
8
in the opposite, clockwise, sense between the second and the first angularly-spaced positions, the dosing unit
16
remains stationary and the resilient member is located behind the axially-directed surface
60
a
of the adjacent wedge-shaped element
60
; the resilient member riding over an inclined surface
60
b
of the adjacent wedge-shaped element
60
.
Although the above-described known powder inhaler functions quite adequately, powder may accumulate on surfaces in the flow path through the inhaler.
It is thus an aim of the present invention to provide a powder inhaler having a construction which is such as to reduce the possibility of powder accumulating on surfaces in the flow path therethrough.
Accordingly, the present invention provides a powder inhaler for administering powder by inhalation, comprising: a flow path defined by a plurality of surfaces through which a stream of air is in use drawn on inhalation by a user; and dosing means for providing a dose of powder to the flow path for entertainment in the stream of air; characterized in that the inhaler further comprises dislodging means for dislodging powder accumulated on a surface of the flow path downstream of the dosing means.
The present invention also provides a powder inhaler for administering powder by inhalation. comprising: a housing having a screw thread; a mouthpiece attached to the housing so as to be rotatable relative thereto; and a cap for covering at least the mouthpiece, the cap having a screw thread for engaging the screw thread on the housing; characterized in that the mouthpiece and the cap are adapted such that at least a part of the mouthpiece is rotated relative to the housing on one of screwing or unscrewing the cap, which part of the mouthpiece substantially remains in fixed position relative to the housing on the other of screwing or unscrewing the cap.
By virtue of the present invention, powder which may have accumulated on inner surfaces of the inhaler is dislodged from those surfaces prior to the next inhalation. Powder is thus prevented from accumulating within the inhaler beyond a single use. In
Andersson Jan
Conway John
Dagsland Allan
Friess Stefan
Heckenmueller Harald
Astrazeneca AB
Fish & Richardson P.C.
Weiss Joseph F.
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