Surgery – Liquid medicament atomizer or sprayer
Reexamination Certificate
1998-05-08
2002-09-10
Lewis, Aaron J. (Department: 3761)
Surgery
Liquid medicament atomizer or sprayer
C128S203150
Reexamination Certificate
active
06446626
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.
EP-A-0237507 discloses one such powder inhaler. 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.
Powder inhalers are, however, particularly susceptible to the effects of moisture. In order to alleviate problems associated with moisture uptake it has been proposed to include a desiccant, such as silica gel, in the inhaler to absorb any moisture. It has also been proposed to provide the inhaler with a cap which is either screwed or pressed onto the inhaler body so as to close any flow paths between the stored powder and atmosphere.
DE-C-4415462 discloses a powder inhaler comprising a housing and a cap which is a screw fit to the housing. The cap includes a sealing collar which sealingly engages the inner surface of the neck of the housing when screwed thereto.
In powder inhalers of the kind as disclosed in EP-A-0237507 which comprise an inhaler body and a grip portion at one end thereof, which grip portion is rotatable relative to the inhaler body so as to provide a dose of powder for inhalation, it has been proposed to provide a chamber in the grip portion for containing desiccant and to provide a cap which covers substantially all of the inhaler body and is screwed onto the grip portion so as to seal therewith and thereby exclude moisture from the inhaler body in which the powder is stored.
FIGS. 1
to
3
illustrate 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 (not illustrated) is visible so as to provide an indication as to the usage of the inhaler. The inhaler further comprises a cap
14
comprising a tubular section having a closed end which is configured to fit over the mouthpiece
2
and the inhaler body
6
. The cap
14
includes a sealing surface
15
at the inner peripheral edge of the lip
16
at the open end thereof, which sealing surface
13
tapers outwardly in the direction from the closed to the open end of the cap
14
. The cap
14
further includes screw threads
17
provided to the inner surface thereof.
The grip portion
8
comprises first and second hollow parts
18
,
20
which are mutually configured so as to define an enclosed chamber
22
for containing desiccant when fitted together.
The first part
18
comprises a tubular section
24
, in this inhaler of generally cylindrical cross-section, having a circumferential ridge
26
disposed about the outer surface of one, the upper, end thereof to which the inhaler body
6
is clipped and screw threads
28
to which the cap
14
having corresponding screw threads
17
is screwed so as to cover the mouthpiece
2
and the inhaler body
6
and thus form a tight seal. The first part
18
further comprises an upwardly-directed resiliently-biased arm
30
disposed at the periphery of the upper end thereof, which arm
30
, on rotation of the grip portion
8
, engages part of the dosing mechanism so as to provide a dose of powder for inhalation. The first part
18
yet further comprises a transverse wall
32
which is permeable to moisture. The wall
32
is preferably formed at least in part of cardboard.
The second part
20
comprises a tubular section
34
, in this inhaler of generally cylindrical cross-section, one, the lower, end of which is closed by a wall
36
. The outer surface of the tubular section
34
includes a plurality of axially-directed ridges
38
which are gripped by a user on rotation of the grip portion
8
and a sealing surface
40
at the outer peripheral edge of the lip
41
at the open end thereof, which sealing surface
40
tapers inwardly in the direction from the closed to the open end of the second part
20
. In another inhaler the axially-directed ridges
38
could be replaced by a knurled surface. In this inhaler the inner dimension of the tubular section
34
is configured so as to be a close radial fit over the tubular section
24
of the first part
18
.
In use, the cap
14
is first removed by unscrewing in one sense, in this inhaler in the counter-clockwise sense when viewed from above. The grip portion
8
is then rotated in one sense, in this inhaler also in the counter-clockwise sense when viewed from above, through a predetermined angle relative to the inhaler body
6
and back in the opposite, clockwise, sense to the original position. This action operates the dosing mechanism to provide a dose of powder for inhalation. The user then takes the mouthpiece
2
in the lips and inhales so as to draw powder into the lungs. After use, the cap
14
is then replaced by screwing on in the other, clockwise, sense when viewed from above. In screwing on the cap
14
the sealing surface
15
on the cap
14
is brought into engagement with the sealing surface
40
on the grip portion
8
, with a right seal being achieved by screwing the cap
14
tightly to the grip portion
8
.
Whilst acceptable, there are a number of drawbacks associated with this sealing arrangement. Firstly, if the cap
14
is not screwed onto the grip portion
8
tightly enough, a proper seal will not be made and there will be a risk that the cap
14
will work loose and fall off. Conversely, if the cap
14
is screwed too tightly onto the grip portion
8
, a user may find the cap
14
difficult to remove. Indeed, where the cap
14
is screwed too tightly onto the grip portion
8
, it is possible that the lip
16
on the cap
14
or even the lip
41
on the grip portion
8
may be damaged. This is particularly the case where the inhaler is assembled by machine as it is likely that the machine may overtighten the cap
14
.
It is thus an aim of the present invention to provide an inhaler in which the seal with the cap is achieved without the cap having to be screwed overly tightly.
Accordingly, the present invention provides an inhaler for administering powder by inhalation, comprising: a housing having a screw thread and a substantially circular sealing surface coaxial therewith; a mouthpiece attached to the housing; and a cap for covering at least the mouthpiece, the cap having a screw thread for engaging the screw thread on the housing and a substantially circular scaling surface for engaging the scaling surface on the housing; wherein the sealing surfaces are shaped and dimensioned such that the radial force therebetween is substantially constant for any relative position where the sealing surfaces engage one another; characterized in that the housing comprises a body and a grip portion which is rotatable relative to the body and on rotation provides a dose of powder for inhalation, in that the screw thread and the sealing surface on the housing are provided on the grip portion and in that the sealing surface on the grip portion is disposed axially forward, in the direction of fitting the cap to the housing, of the screw thread on the grip portion.
Preferably, the sealing surface on the grip portion comprises a substantially cylindrical outwardly-facing surface.
Preferably, the sealing surface on the cap comprises a substantially cylindrical inwardly-facing surface.
Preferably, the sealing surface on the grip portion is provided by a circular l
Astra Aktiebolag
Fish & Richardson P.C.
Lewis Aaron J.
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