Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
Dry Powder Inhaler
Backqround of the Invention
This application is a continuation-in-part of Serial
No. 08/428,960, filed April 29, 1995 and now pending, and
incorporated herein by reference.
Field of the Invention
The field of the invention is inhalers. More
specifically, the invention relates to inhalers for
delivering drugs in a solid finely divided dry powder or
fluid form.
Inhalers are used to deliver drugs into a patient's
lungs. Typically, an inhaler contains or provides a
mixture of drugs and air or propellants. The mixture is
delivered via the patient inhaling from a mouthpiece on
the inhaler, for treatment of various conditions, for
example, bronchial asthma. However, delivery of drugs via
inhalation can be used for many other treatments,
including those unrelated to lung condition.
One well known inhaler, the Diskhaler, described in
U.S. Patent No. 4,627,432, uses individual drug doses
sealed within blisters on a blister disk. The disk is
advanced by a knob with each successive dose. However,
while the device described in U.S. Patent No. 4,627,432
has met with varying degrees of success, disadvantages
remain in indexing or advancing a blister disk within an
inhaler, with opening the blisters to access the drug
contents, with reliably providing intended dosages, and in
other areas.
Accordingly, it is an object of the invention to
provide an improved inhaler.
,
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SummarY of the Invention
To these ends, the present inhaler preferably
includes a cover plate pivotably attached to a lid on an
inhaler housing. A blister pack disk is rotatably mounted
on the housing under the cover plate, and is movable in a
single forward direction. An actuator in the housing is
most desirably aligned with a lever on the cover plate.
The patient pushes the actuator which shears open a
blister on the disk and then causes the lever to crush the
blister, to deliver the drug powder contents of the
blister into a duct within the housing, for subsequent
inhalation by the patient.
Other and further ob~ects will appear hereinafter.
Brief Description of the Drawinqs
In the drawings, wherein similar reference characters
denote similar elements throughout the several views:
Figure 1 is perspective view of the present inhaler
with the mouthpiece covered by the cover assembly;
Figure 2 is a perspective view thereof with the
mouthpiece uncovered;
Figure 3 is a plan view of the inhaler as shown in
Figure 1;
Figure 4 is a plan view of the inhaler as shown in
Figure 2;
Figure 5 is an exploded perspective view of the
inhaler of Figures 1 and 2;
Figure 6 is an plan view of the inhaler of Figures 1
and 2 with the lid open;
Figure 7 is a partial section view taken along line
7-7 of Figure 6;
Figure 8 is an enlarged top and front perspective
view of the cover assembly on the inhalers of Figures 1
and 2;
Figure 9 is a bottom and rear perspective view of the
cover assembly of Figure 8;
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Figure 10 is an enlarged view of features shown in
Figure 9;
Figure 11 is a partial section view taken along line
11-11 of Figure 5;
Figure 12 iS similar view showing positions of
various components during use of the device;
Figure 13 is a partial section view taken along line
13- 13 of Figure 3;
Figure 14 is a partial section view taken along line
14-14 of Figure 4;
Figures 15, 16 and 17 are partial section view
fragments illustrating movement of components within the
device;
Figure 18 is a section view taken along line 18-18 of
Figure 5;
Figure 19 is a similar view thereof with various
components omitted for drawing clarity, and showing
positions of components during use;
Figure 20 iS an exploded perspective view of a
blister disk for use with the inhaler shown in Figures 1
and 2;
Figure 21 iS a partial plan view thereof; and
Figure 22 is a section view taken along line 22-22 of
Figure 21.
Detailed Description of the Preferred Embodiments
Turning now in detail to the drawings, as shown in
Figures 1-4, a dry powder inhaler includes a housing 32
having a lid 38 attached to the housing with a hinge 36.
The lid 38 iS preferably a transparent material, e.g.,
clear plastic. A removable mouthpiece 34 iS provided on
one side of the housing 32. A sliding cover assembly 40
may be pivoted on the lid 38 from a closed position
covering the mouthpiece 34, as shown in Figures 1 and 3,
to an opened position exposing the mouthpiece 34, as shown
in Figures 2 and 4. As best shown in Figures 3 and 4
(looking down through the transparent lid 38), a disk 42
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having a plurality of radially spaced apart blisters 44 ig
generally centered on top of the housing 32 on a center
post 140 extending upwardly from the housing 32. A lid
stop 46 on the housing 32 limits sliding movement of the
cover assembly 40 in the opened position.
Turning momentarily to Figures 8 and 9, the sliding
cover assembly 40 includes an enclosure 48 having a front
curved wall 54, a side wall 56, a top wall 58 and a bottom
wall 60. A rim 62 extends upwardly and radially inwardly
on the top wall 58. Referring now to Figure 9, a
glide block 64 and an outside retainer 66 extend
downwardly and inwardly on the underside of the top wall
58. A generally flat cover plate 50 iS preferably
integrally formed with the enclosure 48, with the cover
--~ 15 plate 50 and enclosure comprising the cover assembly 40.
An inside retainer 68 on the cover plate 50 extends
radially outwardly. A lever 74 iS pivotably supported on
a lever pin 76 held in place by lever blocks 72 on the
underside of the cover plate 50. The lever 74 can pivot
through a lever opening 78 in the cover plate 50, as best
shown in Figure 8. A ramp 80 and a guide wall 82 project
downwardly from the cover plate 50, adjacent to the lever
74, as shown in Figure 9. The entire cover assembly 40,
which includes the enclosure 48 and cover plate 50 iS
pivotably attached to the lid 38, with the lid post 52
extending through a center hub 84 on the cover plate 50.
Clearance holes 70 through the cover plate 50 on either
side of the lever opening 78 allow the cover plate to sit
on top of the blister disk, as shown in Figure 18, without
excessive vertical interference.
Referring to Figures 8, 9 and 10, a spring arm 86
having a downwardly projecting end tab 88 iS attached to
or integral with the cover plate 50. As shown in Figure
13, the spring arm 86 includes an arm wedge 96 at its free
end, alongside the tab 88. As shown in Figure 10, an arm
lifter 102 extends downwardly from the lid 38. An outer
slot 94 through the cover plate 50 overlies the spring arm
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86. An inner slot 92 adjoining the outer slot 94 through
the cover plate 50 provides clearance for the arm lifter
102, and allows the cover assembly 40 to rotate
(preferably about 90~). The arm lifter 102 includes an
internal ramp, and is dimensioned to engage the arm wedge
96, and lift the arm 86 up towards the lid 38, as the arm
wedge 96 moves into full engagement with the lifter 102.
Turning now to Figure 5, the housing 32 includes a
mixing chamber 120, and a staging chamber 124 connected to
the mixing chamber 120 via a duct 122. Referring now also
to Figures 6 and 7, an inlet duct 126 extends from one
side of the housing 32 to the staging chamber 124 via a
duct recess 130. A crescent barrier 128 around the top of
the staging chamber 124 creates an indirect air flow path
from outside of the housing, through the inlet duct 126
and into the staging chamber 124.
In a first embodiment of the present invention,
referring once again to Figure 5, a pressure port or
opening 132 in the housing 32 alongside the mixing chamber
120 connects to a pressure switch 170 via a tube 172. The
pressure port aligns with a mouthpiece port 135 leading
into the central opening of the mouthpiece. This provides
a continuous duct from the mouthpiece opening to the
pressure switch. The mouthpiece 34 or an alternative
embodiment mouthpiece 136 is secured to the housing 32
with a hook 134. The mouthpiece is removable by twisting
or rotating the mouthpiece, to disengage the hook 134, and
then by pulling it off. Rachet posts 142 having angled
top surfaces project slightly above the flat top surface
138 of the housing 32. An actuation button 146 has a post
148 extending entirely through a post opening 144 in the
housing 32.
Referring momentarily to Figure 18, a 147 detent on
the housing engages and holds the post 148 in the up
position (driving the lever to crush a blister), until the
disk is advanced to the next blister. At the front of the
housing, behind the mixing chamber 120, is an inwardly
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projecting housing inner rim 150, and an outwardly
projecting housing outer rim 152. The outer rim 152 is
engaged by the outside retainer 66, and the inner rim is
engaged by the inside retainer 68, as the cover assembly
40 is moved between opened and closed positions. The
interaction of the inner rim 150 and inside retainer 68
and outer rim 152 and outside retainer 66, holds the cover
assembly and lid down on top of the housing 32.
Referring still to Figure 5, a bottom cover 158
attached to the housing 32 has a button recess 164 around
the actuation button 146, so that the actuation button 146
does not project beyond the bottom surface of the cover
158. An impeller 162 within the mixing chamber 120 is
supported on the shaft of an electric motor 160 behind the
mixing chamber 120 in the housing 32. The motor 160 is
wired to batteries 168 and the pressure switch 170. A
battery indicator LED 174 and a status indicator LED 176
are positioned in the housing 32, above the pressure
switch 170.
Turning now to Figures 20-22, the disk 42 includes a
blister foil ring 190, preferably a metal or aluminum foil
having generally conical blisters formed in it. The
blister foil ring 190 and a foil seal ring 192 are adhered
or bonded onto a carrier disk 194. As shown in Figure 21,
the carrier disk 194 has tabs 196 suspended within tab
slots 198 by bridges 200. Each blister 44 on the blister
foil ring 190 is aligned over a tab 196. The bridges 200
hold the tabs 196 in position, but allow the tab to pivot
about the bridges, with nominal torque. As shown in
Figure 22, powdered drug 202 is sealed within the blisters
44.
The carrier disk 194 is preferably plastic. The tab
supports 200 are small enough to support the tabs 196, but
also to allow the tab to pivot under force of the post of
the actuation button. In use, a disk 42 is first loaded
into the inhaler 30 by sliding the cover assembly 40 from
the closed position shown in Figure 1 to the open position
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shown in Figure 2. In this position, the lid 38 and cover
assembly 40 are still held down on top of the housing 32
by the interaction of the outside retainer 66 and inside
retainer 68 on the housing outer rim 152 and inner rim
150. The side wall 56 of the enclosure 48 is lifted
slightly away from the housing 32, to a allow it to pass
over the lid stop 46. As this occurs, the retainers 66
and 68 move off of and release from the inner and outer
rims 150 and 152. The cover assembly 40 and lid 38 are
then pivoted upwardly about the hinge 36, to open up the
inhaler 30, as shown in Figure 6, for placement or
replacement of a disk 42.
A disk 42 is placed over the center post 140 over the
housing top surface 138 with the blisters 44 on top. The
-- 15 lid 38 and cover assembly 40 are pivoted back about the
-~ hinge 36, from the position shown in Figure 6, to the
position shown in Figure 2. The inhaler 30 is then ready
for use.
The rachet posts 142 on the housiny top surface 138
projects slightly into the open ends 203 of the tab slots
198. The disk 42 is accordingly oriented so that a
blister 44 will be aligned over the staging chamber 124.
The rachet posts 142 also prevent the disk 42 from moving
in reverse (i.e., clockwise in Figure 6).
With the lid 38 closed, but with the cover assembly
- 40 opened (as shown in Figure 2), the inner end of the
~ lever 74 is aligned over the top of the post 148. The
outer end of the lever 74 is aligned over the top of a
blister 44, and over the staging chamber 124.
With the inhaler 30 preferably held upright, the
actuation button 146 is pushed up. As shown in Figures
11, 12 and 19, the upward movement of the post 148 on the
actuation button 146 first pivots the tab 196 on the
blister 44 over the staging chamber 124. The tab pivots
on the bridges 200. As this occurs, the foil seal ring
192 sealing the blister 44 on the bottom shears away
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opening the blister and allowing the powdered drug 202 to
fall into the staging chamber 124.
As upward movement of the post 148 continues, the
post pivots the lever 74 causing the outer end of the
lever to crush the blister 44 down, to release any
residual powder into the staging chamber 124.
With one dose of the powdered drug now delivered from
a sealed blister 44 into the staging chamber 124, the
patient places the mouthpiece 34 into the mouth and
inhales. The inhalation draws air from outside of the
housing through the inlet duct 126, around and under the
crescent barrier 128 and into the staging chamber 124.
Air and powdered drug 202 move through the duct 122 and
into the mixing chamber 120. At the same time, upon
inhalation, the reduced air pressure at the mouthpiece 136
is detected by the pressure switch 170 via the tube 172
extending to the pressure port 132. The switch 170 turns
on the motor 160, spinning the impeller 162 within the
mixing chamber 120. The spinning impeller tends to
further draw in air and powdered drug through the duct 122
into the mixing chamber 120. The air and drug is mixed in
the mixing chamber 120, as further described in U.S.
Patent No. 5,327,883, and U.S. Patent Application Serial
No. 08/137,282 filed October 14, 1993, incorporated herein
by reference. As the impeller is already spinning at high
speed when the drug enters the mixing chamber, the
air/drug mixing and deagglomeration are enhanced.
The patient inhales on the mouthpiece drawing in the
air/drug mixture from the mixing chamber 120 via holes 125
in the rear wall of the mouthpiece 34 (which rear wall
also forms the front wall of the mixing chamber 120).
To prepare for delivery of the next dose, the cover
assembly 40 is moved from the position shown in Figure 2,
to the position shown in Figure 1, to cover the mouthpiece
34. As this closing movement of the cover assembly 40
occurs, the arm wedge 96 on the spring arm 86 is released
from the lifter 102. This allows the spring arm 86 to
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flex downwardly with the tab 88 engaging into the opened
end 203 of a tab slot 198, approximately at position A as
shown in Figures 3 and 6. With the continued closing
motion of the cover assembly 40 to the position shown in
Figure 3, the tab 88 on the spring arm 86 advances the
disk 42 to the next blister 44 (moving the disk 42
counter-clockwise in Figure 3). For a disk having 16
blisters, the advancing movement, from engagement of the
tab 88 to the disk 42, until the end of movement, is about
22~. As the disk 42 iS advanced by the spring arm 86 on
the closing cover assembly 40, the disk 42 rides up and
over the angled top surfaces of the rachet posts 142 and
then settles back down onto the housing surface 138 with
the rachet posts 142 engaged into the next set of opened
ends 203 of the tab slots 198. In this manner, the next
blister 44 on the disk 42 iS positioned for delivery and
inhalation, as described above. When the cover assembly
40 iS reopened, to the position shown in Figure 4, the
disk 42 does not move, as the spring arm 86 iS lifted up
and out from engagement with the disk by the interaction
of the lifter 102 on the lid 38 and the arm wedge 96 on
the spring arm 86. Through this repeated motion of
opening and closing the cover assembly 40, each blister 44
on the disk 42 can be sequentially accessed, until all of
the blisters are used.
As the cover assembly 40 iS closed, the ramp 80 on
the cover plate 50 rides over the top of the post 148, the
push it down, resetting the actuation button 146 for the
next dose, as shown in Figures 15-17. Simultaneously, the
guide wall 82, which ramps upwardly from the lever 74,
pushes down on the pivoted tab 196 from the blister
delivered. The tab 196 iS accordingly pushed back down
into the plane of the disk 42, SO that the disk can be
advanced without interference. The rachet posts 142
prevent the disk 42 from moving in reverse (clockwise in
Figure 3) at anytime.
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Accordingly, a novel inhaler is described and shown
with various advantages over the prior art design. The
above-described inhaler may contain various changes and
modifications, including various substitutions and
equivalents, without departing from the spirit and scope
of the present inventio~.
