Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1999-05-10
2001-12-04
Weiss, John G. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S203120
Reexamination Certificate
active
06325061
ABSTRACT:
BACKGROUND OF THE INVENTION
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.
EP-A-0237507 discloses one such powder inhaler. This inhaler comprises an inhalation channel and a mouthpiece which includes 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 a dosing mechanism for providing a dose of powder to 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 an inhaler unit
1
and a cap
2
which is a screw fit to the same. The inhaler unit
1
comprises a mouthpiece
3
which includes 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
11
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
12
which is fixed thereto. For aesthetic reasons the inhaler body
6
is an opaque moulding. The divider
12
is a transparent moulding which includes a peripheral groove
13
and an adjacent peripheral ridge
14
by which the mouthpiece
3
is attached thereto. The divider
12
further includes a depending tongue
15
, a part of which forms the window
11
.
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 elements
18
are provided and a s haft
20
which extends axially from the centre of the member
17
, a distribution 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 distribution 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
12
. In this way, the distribution 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 chamber
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 distribution unit
22
further comprises scrapers
40
which are resiliently biased against the surface of the member
17
of the dosing unit
16
in which the dosing elements
18
are provided. In this way, as the dosing unit
16
is rotated, the dosing elements
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 elements
18
by a plate (not illustrated) which is disposed beneath the dosing unit
16
.
The divider
12
further includes a supporting member
41
for rotatably supporting an indicating wheel
42
. The indicating wheel
42
includes 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
of the dosing unit
16
. The supporting member
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
11
. 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
11
as to the usage of the inhaler.
As illustrated in
FIG. 4
, the mouthpiece
3
is fixed to the divider
12
. The mouthpiece
3
comprises first and second parts
48
,
50
, the first part
48
being the part which is gripped in 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
12
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. The flange
56
includes a downwardly-depending annular skirt
59
which is a tight fit within the first part
48
and acts to fix the second part
50
to the first part
48
.
In use, as described hereinabove, powder is transferred from the storage chamber
28
to one of the dosing elements
18
, and, with rotation of the dosing unit
16
, the one dosing element
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 clockwise sense when viewed from below between first and second angularly-spaced positions. For this purpose, the dosing unit
16
includes wedge-shaped elements
60
disposed around the periphery of the member
17
thereof 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, counter-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
.
SUMMARY OF THE INVENTION
Whilst this powder inhaler functions perfectly adequately, it is an aim of the present invention further to improve the transfer of powder through the air chamber.
Accordingly, the present invention provides a powder inhaler for administering powder by inhalation, comprising a chamber which includes a base member and a peripheral wall member, wherein the chamber includes a first inlet through which a first stream of air containing powder is in use drawn on inhalation by a user and a plurality of second inlets at the junction between the base member and the peripheral wall member through which a plurality of second streams of air of combined lesser flow than the first stream of air are in use drawn on inhalation by the user so as to minimise retention of powder at the junction between the base member and the peripheral wall member.
In this way, the supplementary streams of air drawn through the second inlets pass over an inner peripheral surface of the chamber, preferably along the peripheral wall member towards the outlet thereof. These supplementary streams of air ensure that there are no dead spots or stagnant regions in the chamber. As a result, the likelihood o
Astra Aktiebolag
Fish & Richardson P.C.
Mitchell Teena
Weiss John G.
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