Dry powder inhaler with blister bursting device

Abstract

A multi-dose dry powder inhaler with a blister folding device is provided. The inhaler comprises a housing containing a blister strip, and a blister opening device. The blister strip comprises a plurality of individual blisters, each blister containing a dose of medicament for inhalation by a user. The blister opening device comprising a blister support element for supporting one of said blisters, and a blister folding element co-operable with the blister support element, the blister folding element and the blister support element being movable relative to each other between a first position, permitting movement of said blister into or onto the blister support element, and a second, burst, position in which the blister folding element has co-operated with the blister support element. Movement from the first position to the second position causes two spaced apart portions of said blister to each fold relative to the remainder of the blister to produce two spaced apart openings, each opening extending along the circumference of the blister bowl, beginning and terminating at points located on the fold line No piercing of the blister at any stage is required.

Claims

1. A dry powder inhaler comprising a housing defining a chamber, a blister strip comprising a plurality of blisters, each blister of said plurality of blisters containing a dose of medicament for inhalation by a user, each blister of said plurality of blisters comprising a blister lid attached to a blister bowl, the blister strip being disposed inside the chamber, an actuator, an indexing system configured to sequentially move each blister of said plurality of blisters into a blister opening position in response to movement of the actuator, said indexing system comprising a blister strip drive member rotatably mounted in the chamber, said blister strip drive member comprising an indexing wheel, the indexing wheel comprising a plurality of blister seats and two radially extending and spaced apart major, planar surfaces, each blister seat of said plurality of blister seats configured to support a central portion of the blister bowl of any one of the plurality of blisters, each blister seat of said plurality of blister seats being equi-angularly spaced apart about an axis of rotation of the indexing wheel, and each blister seat of said plurality of blister seats having two edges on two, respective opposing sides of the blister seat corresponding to said two radially extending and spaced apart major, planar surfaces such that two, respective spaced apart portions of the blister bowl are not supported by the blister seat, a mouthpiece through which the dose of medicament is inhaled by the user, and a blister opening device, the blister opening device comprising a blister folding element comprising two pairs of spaced apart fold members, wherein the blister folding element is co-operable with the indexing wheel, and wherein the blister folding element is movable relative to the indexing wheel between a first position, permitting movement of said blister into or onto one of the plurality of blister seats, wherein the two pairs of spaced apart fold members are not disposed on either of said two radially extending and spaced apart major, planar surfaces of the indexing wheel, and a second, burst, position in which the blister folding element has co-operated with the indexing wheel to move the two pairs of spaced apart fold members to be contiguous along one of said two radially extending and spaced apart major, planar surfaces to contact the two, respective spaced apart portions of the blister bowl to produce two spaced apart openings in the blister, each opening extending along a circumference of the blister bowl, beginning and terminating at points located on a fold line such that, when the user inhales through the mouthpiece, an airflow through the blister via the two spaced apart openings is generated to entrain the dose contained therein and carry it out of the blister and via the mouthpiece into the user's airway.

2. The dry powder inhaler of claim 1, wherein the blister folding element is slidable relative to the indexing wheel.

3. The dry powder inhaler of claim 1, wherein each blister seat of the plurality of blister seats comprises a central portion which has a truncated geometric shape, each fold line being one edge of truncation.

4. The dry powder inhaler of claim 1, wherein a longitudinal extent of each blister seat of said plurality of blister seats is arranged perpendicularly to a direction of travel of the blister strip during indexing.

5. The dry powder inhaler of claim 1, wherein each blister seat of said plurality of blister seats comprises a raised feature configured to cause an indentation at a base of the blister bowl for internally pressurising the blister.

6. The dry powder inhaler of claim 1, wherein the actuator is an actuating lever and wherein said actuating lever is pivotally mounted to the housing.

7. The dry powder inhaler of claim 6, wherein said actuating lever is configured to operate in a stroke, and wherein the actuating lever is configured to cause blister indexing during a first portion of its stroke, and to cause blister folding during a second and subsequent portion of its stroke.

8. The dry powder inhaler of claim 1, wherein the actuator is a cap, and wherein said cap is pivotally mounted to the housing.

9. The dry powder inhaler of claim 1, further comprising a deagglomeration chamber configured to deagglomerate a powder from each blister of said plurality of blisters when opened.

10. The dry powder inhaler of claim 1, further comprising an unfolding member configured to return folded portions of each blister of said plurality of blisters back to its original unfolded conditions after each blister of said plurality of blisters has been folded.

11. The dry powder inhaler of claim 1, wherein the blister strip comprises two longitudinal edges, and wherein each longitudinal edge comprises a series of spaced apart fold ears which extend laterally outwardly from said longitudinal edge.

Description

(1) An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:—

(2) FIG. 1 shows a front view of a lever operated embodiment of the inhaler according to the invention, in which the lever is in a raised position, and the inhaler is in a rest condition;

(3) FIG. 2 shows a rear view of the inhaler of FIG. 1;

(4) FIG. 3 shows a front view of the inhaler, in which the lever is in a lowered position, and the inhaler is in an active condition, ready for inhalation;

(5) FIG. 4 shows a rear view of the inhaler of FIG. 3;

(6) FIG. 5 shows a plan view of a first embodiment of the blister strip;

(7) FIG. 6 shows a plan view of a second embodiment of the blister strip;

(8) FIG. 7 shows a front cross-sectional view of the inhaler of FIG. 3 with certain features omitted for clarity;

(9) FIG. 8 shows an enlarged view of the blister support element, and the actuating lever;

(10) FIG. 9 shows an enlarged view of the blister support element at the moment blister folding occurs;

(11) FIG. 10 shows a prototype jig for a unit dose device before blister opening, to demonstrate the effect of folding on the blister;

(12) FIG. 11 shows the prototype jig of FIG. 11 after blister opening, in which two large apertures have been formed in the blister; and

(13) FIG. 12 shows an unfolding member.

(14) Referring firstly to FIGS. 1 to 4, a multi-dose dose dry powder inhaler is indicated generally at 10. The inhaler 10 comprises a housing 12 defining a chamber 14, a blister strip 16 inside the chamber 14, a mouthpiece 18 through which a dose of medicament is inhaled by a user, an actuator, an indexing system to sequentially move each blister into a blister opening position 20 in response to movement of the actuator, and a blister opening device.

(15) The chamber 14 is essentially divided into two compartments, separated by a movable wall 22. Such a wall 22 has been described in Applicant's own WO 2012/069854. Before first use of the inhaler 10, a coil of unused blister strip 16 is stored inside a first compartment 24. As the blister strip 16 is advanced by the indexing system, the blister strip 16 uncoils and progresses towards the blister opening position 20. Subsequent indexing causes the opened (i.e. used) portion of the blister strip 16 to move into a second compartment 26, and the used portion of the blister strip 16 to gradually recoil. The movable wall 22 is slidable within the chamber 14 to automatically adjust the relative capacity of the first and second compartments 24, 26 as the diameter of the unused portion of the blister strip 16 coil decreases and the diameter of the used portion of the blister strip 16 coil increases. Alternatively, the movable wall 22 may be pivotally mounted within the chamber 14.

(16) The blister strip 16 comprises a plurality of blisters 28 (see FIGS. 5 and 6), each containing an individual dose of medicament for inhalation by a user. Each blister 28 comprises a blister lid 27 attached to a blister bowl 29. Preferably the blister bowl 29 is oval, but other geometric shapes may be used. Exemplary blister strips are shown in FIGS. 5 and 6. Either configuration of blister strip 16 may be used, but the one shown in FIG. 6 is considered to work better in practice.

(17) In FIG. 5, blister strip 16a incorporates two lines of weakness 30 between adjacent blisters 28. Each line of weakness 30 extends partially across the breath of the blister strip 16a. Alternatively, a single line of weakness 30 may extend across the full breath of the blister strip 16a. The line of weakness 30 is typically formed by scoring into the uppermost layer of the blister strip 16a, but not other layers below, for example using a laser. By not affecting the layers below, the moisture protection of the blister strip 16a is retained. One way of achieving such a line of weakness 30 has been described in the Applicant's own WO 2006/108876. Other variations on the number and length of the or each line of weakness 30 are envisaged.

(18) In FIG. 6, blister strip 16b has two longitudinal edges 32, each edge 32 comprising a series of spaced apart fold ears 34 which extend laterally outwards. In other words, in plan view, each edge resembles a square tooth wave profile. There is a notch 36 adjacent to each fold ear 34. The notch 36 extends into each blister strip 16b such that it laterally passes the end of the blister bowl 29. As such, a virtual fold line extends longitudinally from recess to recess, bisecting the end of the blister bowl 29.

(19) The mouthpiece 18 is mounted to the housing 12. The mouthpiece 18 does not move relative to the housing 12.

(20) The actuator is operable to cause indexing of the blister strip 16 and subsequently blister 28 opening, as will be described in further detail below. In this embodiment, the actuator is an actuating lever 38 pivotally mounted to the housing 12 about a first axis of rotation 39. Preferably, the actuating lever 38 comprises an actuating button 40 that extends across the outside of the housing 12 between opposing side wall surfaces 42 of the housing 12, and a plate-like portion 44 extending from each end of the actuating button 40 across respective side wall surfaces 42 on the outside of the housing 12.

(21) Alternatively the actuator may comprise a cap pivotally mounted to the housing 12. Such a cap works in a similar way as the actuating lever 38, but with the resulting inhaler 10 being cap operated as opposed to lever operated. This simplifies operation of the inhaler 10 for the user as it removes the step of opening a passive cover or cap (not shown) in order to operate the actuating lever 38.

(22) The indexing system comprises a blister strip drive member rotatably mounted in the chamber 14 about a second axis of rotation 46. The blister strip drive member comprises an indexing wheel 48 (best seen in FIG. 7) having two radially extending and spaced apart major surfaces 50. These opposing major surfaces 50 are planar. The indexing wheel 48 comprises a plurality of blister seats 52 to support a blister bowl 29. The blister seats 52 are equi-angularly spaced apart about the axis of rotation 46 of the blister strip drive member. The blister seats 52 are located between the two major surfaces 50. A longitudinal extent of each blister seat 52 is arranged perpendicularly to the direction of travel of the blister strip 16 during indexing. Each blister seat 52 comprises a central portion (not shown) which has a truncated geometric shape, and two spaced apart lines of truncation 54 (best seen in FIG. 9). Each line of truncation 54 coincides with a respective peripheral edge of the one of the two major surfaces 50. The shape of the central portion complements the shape of the blister bowl 29 such that a blister bowl 29 is at least partially nestable within one of the blister seats 52.

(23) Optionally, each blister seat 52 may incorporate a raised feature to cause an indentation at the base of the blister bowl 29 for internally pressurising the blister 28 prior to opening.

(24) The blister strip drive member also comprises a drive gear 56, and the actuating lever 38 comprises a drive gear element 58. The drive gear element 58 is preferably formed on one of the plate-like portions 44 of the actuating lever 38. The drive gear 56 is connected to the indexing wheel 48 via a shaft 60 that extends through aperture in a side wall surface 42 of the housing 12. The shaft 60 is coaxial with the indexing wheel 48 on the second axis of rotation 46. The drive gear 56 is cooperable with the drive gear element 58 via meshing engagement. The drive gear 56 and drive gear element 58 are disposed on the outside of the housing 12 remote from the chamber 14. They are mounted underneath a cap or cover (not shown) such that they are not visible to the user during normal use.

(25) The blister opening device comprises a blister support element for supporting one of the blisters of the blister strip, and a blister folding element 62, which is co-operable with the blister support element. The blister folding element 62 and the blister support element are movable relative to each other between a first position, permitting movement of said blister into or onto the blister support element during indexing, and a second, burst, position in which the blister folding element 62 has co-operated with the blister support element.

(26) Preferably, the blister folding element 62 is movable relative to the blister support element. More preferably, the blister folding element 62 is slidably movable relative to the blister support element, as it is in this embodiment.

(27) In this embodiment, the blister folding element 62 comprises two pairs of spaced apart fold members 64. One pair of said fold members 64 slides contiguous one of the two major surfaces 50 of the indexing wheel 48. The other pair of said fold members 64 slides contiguous the other of the two major surfaces 50 of the indexing wheel 48. Each of the fold members 64 is spaced apart within a pair to allow space for the lid 27 of the blister 28 to move into during popping/bursting. The two pairs of fold members 64 are connected to an elongate support 66 which is slidably mounted within the housing 12.

(28) The blister support element incorporates the indexing wheel 48 and the aforementioned plurality of blister seats 52. There are four blister seats 52a, 52b, 52c, 52d (see FIG. 9), though more or less blister seats 52 may be used instead. The indexing wheel 48 is square-like, and the four blister seats 52a, 52b, 52c, 52d are situated at ninety degree intervals about the axis of rotation 46 of the indexing wheel 48. For simplicity, in the following explanation the reference view is a front view of the inhaler. During use, the indexing wheel 48 rotates in an anti-clockwise direction about the axis of rotation 46. Blister seat 52a at position zero degrees, this being the blister seat 52 nearest the mouthpiece 18 in FIG. 9, is in the blister opening position 20. Blister seat 52b at position ninety degrees, as measured clockwise from the zero position, contains an unopened blister 28 (not shown). Blister seat 52c is devoid of any blister 28. Blister seat 52d positioned at two hundred and seventy degrees, again measured clockwise from the zero position, contains an opened blister 28 (not shown).

(29) A deagglomeration chamber 65 is mounted within the mouthpiece 18 and is used to deagglomerate powder from the opened blister 28. The position of the deagglomeration chamber 65 relative to the mouthpiece 18 is fixed. The deagglomeration chamber 65 has an inlet 68 at one end for the flow of drug laden air into the chamber 14 from a burst blister 28 and an outlet at its opposite end for the flow of drug laden air out of the mouthpiece 18 and into a patient's airway. The deagglomeration chamber 65 has a longitudinal axis 70 that extends between the inlet 68 and the outlet. Typically, drug laden air swirls about the longitudinal axis 70 during inhalation.

(30) An airflow conduit 72 is located proximate the blister opening position 20. This airflow conduit 72 is telescopic, and can be extended and retracted as required.

(31) The airflow conduit 72 connects the blister folding element 62 to the deagglomeration chamber 65. One end of the airflow conduit 72 is in fluid communication with the blister folding element 62 at or near the blister opening position 20. The other end of the airflow conduit 72 is in fluid communication with the inlet 68 of the deagglomeration chamber 65. The deagglomeration chamber 65 does not move with the blister folding element 62. Thus, when the blister folding element 62 is in the first position for blister indexing, the airflow conduit 72 is in a retracted condition. When the blister folding element 62 is in the second position for blister folding, the airflow conduit 72 is in an extended condition.

(32) As best seen in FIG. 4, the actuating lever 38 has a drive cam surface 74 and the blister folding element 62 has a drive cam element 76. The drive cam surface 74 stands proud from the elongate support 66 of the blister folding element 62. The drive cam element 76 and the drive cam surface 74 are cooperable with each other in response to rotation of the actuating lever 38 so that the blister folding element 62 slides within the housing 12. Such movement of the blister folding element 62 occurs only after blister indexing has taken place.

(33) The actuating lever 38 is operable to cause blister indexing during a first portion of its stroke in a first direction (i.e. downwards), and to cause blister folding during a second and subsequent portion of its stroke in the first direction. During the first portion of the stroke, drive gear 56 and drive gear element 58 cooperate to cause the indexing wheel 48 to rotate through ninety degrees. Drive cam element 76 slides freely within the drive cam surface 74 (se FIG. 2). During the second portion of the stroke, due to the presence of a drive coupling member (not shown), such as the one described in Applicant's own EP2254632, movement of the actuating lever 38 is disengaged from rotation of the indexing wheel 48. Therefore, further indexing is prevented. Drive cam element 76 abuts one end of the drive cam surface 74 such that further movement of the actuating lever 38 pulls the blister folding element 62 downwards (see FIG. 4). During the return stroke when the actuating lever 38 moves in a second opposing direction (i.e. upwards), neither indexing nor blister folding occurs. The blister folding element 62 is returned to its first position because the drive cam element 76 abuts the opposing end of the drive cam surface 74. Reverse indexing does not occur due to the drive coupling member.

(34) In preparation for inhalation, movement of the blister folding element 62 from the first position (for example, see demonstration jig 78 in FIG. 10) to the second position (for example, see FIG. 11) causes two spaced apart portions of the blister 28 to each fold relative to the remainder of the blister 28 along a respective fold line 79 and against the blister support element. Each fold line 79 derives from one edge of truncation of the aforementioned truncated geometric shape.

(35) This produces two spaced apart openings 80, 82, each opening 80, 82 extending along the circumference of the blister bowl 29, beginning and terminating at points located on the fold line 79. No piercing or puncturing is required at any time.

(36) Although the images in FIGS. 10 and 11 depict a unit dose device, the actual opening mechanism of folding and popping open is the same for a multi dose device, which is why the demonstration jig 78 has been mentioned here.

(37) During inhalation, when a user inhales through the mouthpiece 18, an airflow through the blister 28 via the two openings 80, 82 is generated to entrain the dose contained therein and carry it out of the blister and, via the mouthpiece 18, into the user's airway. No foil flaps are created that could hinder the flow of powder laden air out of the opened blister 28.

(38) A free end of each fold member 64 may be bevelled. This shaping helps the applied folding pressure be transmitted gradually to the blister 28 as the blister folding element 62 moves from the first to the second position, resulting in a more controlled formation of the openings 80, 82. Bevelled ends help to reduce the overall opening force required of the user.

(39) As shown in FIG. 9, an unfolding member 84 is mounted within the housing 12, preferably near to the blister strip drive member. The unfolding member 84 is located downstream of the blister opening position 20 and upstream of the second compartment 26. The purpose of the unfolding member 84 is to return two folded portions 85 of a recently opened blister 28 back to, or substantially to, an original, unfolded condition. This facilitates a tighter recoiling of the used portion of the blister strip 16 because the folded sections 85 would otherwise hinder recoiling.

(40) The unfolding member 84 is best seen in FIG. 12. A body 86 of the unfolding member 84 is generally cubic. It has a concavely arcuate first (i.e. upper, as viewed in FIG. 12) surface 88 and a planar second (i.e. lower) surface 90 opposing the first surface 88. The curvature of the first surface 88 is perpendicular to the direction of travel of the blister strip 16 during indexing. The body 86 also has a leading third surface 92, which is where the used blister strip 16 approaches the unfolding member 84, and a trailing fourth surface 94, which is where the used blister strip 16 leaves the unfolding member 84. Arrow 95 indicates the direction of travel of the blister strip. Two wings 96, 98 extend laterally outwards from the body 86, with a specific profile designed to unfold folded portions 85 of opened blisters 28. Each wing is part-helical between the leading surface 92 of the body 86 and the trailing surface 94. Each wing 96, 98 blends through ninety degrees, twisting from near vertical to horizontal in a semi-spiral. This results in the formation of a contact surface 100 and a non-contact surface 102 for each wing 96, 98. The two folded portions 85 of each folded blister 28 glide over the contact surfaces 100 during use, starting at the leading surface 92 and by the time the blister 28 (whilst still remaining part of the blister strip 16) has reached the trailing surface 94 the folder portions 85 have been lifted due to the helical nature of the two wings 96, 98.

(41) Many modifications and variations of the invention falling within the terms of the following claims will be apparent to those skilled in the art and the foregoing description should be regarded as a description of the preferred embodiment only.