WO2009150028A1

WO2009150028A1 - Improved injection device

Info

Publication number: WO2009150028A1
Application number: PCT/EP2009/056283
Authority: WO
Inventors: Peter Christian Enggaard; Kristian GLEJBØL; Claus Urup GJØDESEN; Jacob Eiland; Andre Larsen; Claus Schmidt MØLLER
Original assignee: Novo Nordisk A/S
Priority date: 2008-05-26
Filing date: 2009-05-25
Publication date: 2009-12-17

Abstract

An injection device in which a coupling element (30) in permanent rotational engagement with a driver element (50) can be shifted in and out of engagement with a dose dial sleeve (20) such that the drive element (50) can either follow the rotation of the dose dial sleeve (20) and be de-coupled from the dose dial sleeve (20). In the de-coupled position the drive sleeve (50) is guided in non-axial tracks (12) or grooves located on the inside surface of the housing (10).

Description

Improved Injection Device

THE TECHNICAL FIELD OF THE INVENTION:

The invention relates to an improved injection device.

DESCRIPTION OF RELATED ART:

WO 2004/078239 discloses an injection device with a housing and a drive mechanism com- prising a dose dial sleeve having a helical thread engaged with the helical thread of the housing such that the dose dial sleeve can be rotated out of the housing and back into the housing, and a drive sleeve that are releasable connected to the dose dial sleeve through a clutch located between the dose dial sleeve and the drive sleeve, which clutch can be either engaged or disengaged.

When the clutch is engaged, the dose dial sleeve and the drive sleeve is coupled to each other such that they both following the rotational movement of the dose dial sleeve when it is rotated relatively to the housing.

When the clutch is disengaged and the dose dial sleeve and the drive sleeve are de-coupled, the dose dial sleeve rotates in its threaded engagement with the helical thread of the housing while the drive sleeve can move independently of the dose dial sleeve.

The drive sleeve is when de-coupled from the dose dial sleeve coupled to the housing to move axially relatively the injection device. During this axial movement, the drive sleeve forces a piston rod in the distal direction to expel a dose of medicament.

DESCRIPTION OF THE INVENTION:

Claim 1

By de-coupling the dose dial sleeve from the drive sleeve during injection it is ensured that the dose dial sleeve can freely rotate back in its threaded engagement with the housing while the drive sleeve is set free to move independently of the dose dial sleeve. In the preferred solution, the drive sleeve is coupled to non-axial tracks or grooves provided on the inside surface of the housing.

Claim 2-3 To work as a clutch, a coupling sleeve is provided between the dose dial sleeve and the drive sleeve, which coupling sleeve is biased towards its engaging positon by a metal spring located between the drive sleeve and the coupling sleeve.

Claim 4-5 Further an End-of-Content element is provided, which element has a cup shape. The element is threadely engaged with the housing and longitudinal guided in a groove in the housing. During dose setting, the cup shaped element is brought backward in a proximal direction a distance that equals the distance the piston rod is to be brought forward during dosing of the set dose. By providing the piston rod with a geometry that engages with the cup shaped element when the set dose equals the remaining amount in the cartridge an End-of-Content mechanism is provided.

All though this End-of-Content mechanism is described in conjunction with a driver that is guided in a non-linear track during dosing it would also work with a drive guided in an axial track as the one disclosed in WO 2004/078239.

DEFINITIONS

An "injection pen" is typically an injection apparatus having an oblong or elongated shape somewhat like a pen for writing. Although such pens usually have a tubular cross-section, they could easily have a different cross-section such as triangular, rectangular or square or any variation around these geometries.

As used herein, the term "drug" is meant to encompass any drug-containing flowable medicine capable of being passed through a delivery means such as a hollow needle in a controlled manner, such as a liquid, solution, gel or fine suspension. Representative drugs includes pharmaceuticals such as peptides, proteins (e.g. insulin, insulin analogues and C- peptide), and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form. Further the term "injection needle" defines a piercing member adapted to penetrate the skin of a subject for the purpose of delivering or removing a liquid.

"Cartridge" is the term used to describe the container containing the drug such as insulin. Cartridges are usually made from glass but could also moulded from any suitable polymer. A cartridge or ampoule is preferably sealed at one end by a pierceable membrane which can be pierced e.g. by an injection needle. The opposite end is closed by a plunger or piston made from rubber or a suitable polymer. The plunger or piston can be slidable moved inside the cartridge. The space between the pierceable membrane and the movable plunger holds the drug which is pressed out as the plunger decreased the volume of the space.

All references, including publications, patent applications, and patents, cited herein are incorporated by reference in their entirety and to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

All headings and sub-headings are used herein for convenience only and should not be constructed as limiting the invention in any way. The use of any and all examples, or exemplary language (e.g. such as) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability, and/or enforceability of such patent documents.

This invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law.

BRIEF DESCRIPTION OF THE DRAWINGS:

The invention will be explained more fully below in connection with a preferred embodiment and with reference to the drawings in which:

Figure 1 Shows a cross section of an injection pen according to an example of the invention. Figure 2 Shows another cross section of an injection pen according to a different example of the invention.

The figures are schematic and simplified for clarity, and they just show details, which are essential to the understanding of the invention, while other details are left out. Throughout, the same reference numerals are used for identical or corresponding parts.

DETAILED DESCRIPTION OF EMBODIMENT:

When in the following terms as "upper" and "lower", "right" and "left", "horizontal" and "vertical", "clockwise" and "counter clockwise" or similar relative expressions are used, these only refer to the appended figures and not to an actual situation of use. The shown figures are schematic representations for which reason the configuration of the different structures as well as there relative dimensions are intended to serve illustrative purposes only.

In that context it may be convenient to define that the term "distal end" in the appended figures is meant to refer to the end of the injection device carrying the injection needle whereas the term "proximal end" is meant to refer to the opposite end pointing away from the injection needle.

Figure 1 discloses the injection device 1 in which a housing 10 surrounds a dose setting and injection mechanism.

The housing 10 is formed with an internal thread 16 which as shown in figure 1 can be moulded in an insert 15 that during assembly is connected to the housing 10 to at least functionally work with the housing 10 as one integral part.

A dose dial sleeve 20 with an internal thread 23, which are threadely engaged with the housing 10 is located inside the housing 10. Typically dose size markings printed on the dose dial sleeve 20 is visible in a window in the housing 10, or as depictured through the transparent insert 15. The dose dial sleeve 20 is at its proximal end provided with a finger grip 21 which, as disclosed, can be a separate part connected to the dose dial sleeve 20, but which could also be formed as an integral part of the dose dial sleeve 20. Going more inside the injection device 1 the next layer is a coupling sleeve 30. At its distal end the coupling sleeve 30 is provided with a number of V-shaped teeth 31 engaging similar v-shaped teeth 41 on a metal spring 40 located distally of the coupling sleeve 30. At its proxi- mal end the coupling sleeve 30 is provided with a number of not shown stems which abuts the injection button 60 such that the coupling sleeve 30 is moved forward against the bias of the metal spring 40 when the injection button 60 is pressed.

Further, the coupling sleeve 30 has at its proximal end a number of squared teeth 32 that cooperates with similar squared teeth 22 on the inside surface of the dose dial sleeve 20 such that the dose dial sleeve 20 and the coupling sleeve 30 is rotational coupled to each other when the coupling sleeve 30 is in its most proximal position, and which two sleeves 20, 30 is de-coupled when the coupling sleeve 20 is in its most distal position. When a user presses the injection button 60, the coupling sleeve 30 is moved into the space X whereby the coupling sleeve 30 is uncoupled from the dose dial sleeve 20.

The drive sleeve 50 is located inside coupling sleeve 30 and is rotational coupled to the coupling sleeve 30 through a keyed engagement 33, 51 such that they always rotate together but at the same time the two sleeves 30, 50 are able to move axially relatively to each other.

In the centre-line of the injection device 1 , the piston rod 70 is located. The piston rod 70 has two threads 71 , 72, a distal thread 71 engaging an internal thread 1 1 in the housing 10 and a proximal thread 72 engaging a thread 52 on the inner surface on the drive sleeve 50.

Towards the distal end of the drive sleeve 50 a first flange 53 carrying the metal spring 40 is located. This metal spring 40 has a number of lateral extending arms 42 which engages a track 12 on the inner surface of the housing 10. Further, the metal spring 40 has a number of v shaped teeth 41 which is able to co-operate with the v-shaped teeth 31 provided on the distal end of the coupling sleeve 30.

When a user sets a dose she rotates the finger grip 21 and thereby the dose dial sleeve 20 which then screws out of the housing 10. At the same time the user can inspect the size of the dose through the window or transparent insert 15 as the printing on the dose dial sleeve 20 rotates past the window 15. It is apparent that an erroneous high dose setting can easily be reduced by rotating the finger grip 21 in the opposite direction. When the dose dial sleeve 20 is rotated it brings the coupling sleeve 30 and the drive sleeve 50 to rotate with it due to the engagement 22, 32 between the dose dial sleeve 20 and the coupling sleeve 30 and the engagement 33, 51 between the coupling sleeve 30 and the drive sleeve 50. The drive sleeve 50 rotates up the proximal thread 72 on the piston rod 70 which proximal thread 72 has a pitch identical to the internal thread 16 of the housing 10.

During dose setting the V-shaped teeth 31 on the drive sleeve 30 rides over the V-shaped teeth 41 on the metal spring which is rotational engaged with the housing 10 through the lat- eral arms 42 engaging the tracks 12 inside the housing 10.

When the correct dose is set, the set dose is injected by pressing the injection button 60. This pressure moves the coupling sleeve 30 into the space X and releases the dose dial sleeve 20. A continued pressure rotates the dose dial sleeve 20 back into the housing while the drive sleeve 50 is moved forward following the pitch of the tracks 12 since the V-shaped teeth 31 is engaged with the V-shaped teeth 41 on the metal spring 40 such that the coupling sleeve 30 and with it the drive sleeve 50 follows the guided movement of the metal spring 40 having the arms 42 engaged in the tracks 12 inside the housing 10.

This forward motion of the drive sleeve 50 will drive the piston rod 70 forward due to threaded connection 52, 72 between the drive sleeve 50 and the piston rod 70, and the threaded connection 1 1 , 71 between the housing 10 and the piston rod 70 and in that way press the liquid drug out through a not shown injection needle at the distal en of the injection device.

In the most distal end of the drive sleeve 50, a second flange 54 is provided and a thread 55 is provided between the first and the second flanges 53, 54. This thread 55 carries an end of content nut 80.

Figure 2 discloses an alternative end-of-content mechanism.

As can be seen the foremost part of the drive sleeve 50 carrying the second flange 54 and the thread 55 has been replaced by cup shaped element 90 which is guided in longitudinal tracks 13 in the housing 10 such that it can slide forth and back without rotating relatively to the housing 10. This cup shaped element 90 has an internal thread 91 and an opening 92 at its distal end which opening 92 is large enough for the piston rod to penetrate through the cup shaped element 90.

The dose dial sleeve 20 is at its distal end provided with a second external thread 55 which engages the internal thread 91 on the cup shaped element 90.

When a user sets a dose by rotating the dose dial sleeve 20, the cup shaped element 90 will be moved axially in the proximal direction due to the threaded engagement 55, 91 , and when the user injects the set dose and the dose dial sleeve is rotated back to its initial position, the cup shaped element will also return to its initiate position.

By making this threaded engagement 55, 91 such that the cup shaped element 90 will be moved in the proximal direction a distance that equals the distance the piston rod 70 will be moved forward during dosing of the set dose, the opening 90 will engage with the proximal threads 72 on the piston rod 70 when the user sets a dose that is equal to the remaining medicament in the cartridge 5. In this position the cup shaped element 90 will prevent further rotation of the dose dial sleeve 20 and thereby prevent the user from dialling up a dose larger than what is actually left in the cartridge 5.

Some preferred embodiments have been shown in the foregoing, but it should be stressed that the invention is not limited to these, but may be embodied in other ways within the subject matter defined in the following claims.

Claims

Claims:

1. An injection device (1 ) wherein the drive mechanism comprises:

- a housing (10) having a helical thread (16) associated therewith,

- a dose dial sleeve (20) having a helical thread (23) engaged with the helical thread (16) of the housing (10) such that the dose dial sleeve (20) can be rotated out of the housing (10) and rotated back in to the housing (10),

- a drive sleeve (50) releasable coupled to the dose dial sleeve (20) through a clutch located between the drive sleeve (50) and the dose dial sleeve (20) which clutch can be either engaged or disengaged, and wherein,

a) When the drive sleeve (50) and the dose dial sleeve (20) are coupled, both rotate together with respect to the housing (10) when rotated, and

b) When the drive sleeve (50) and the dose dial sleeve (20) are de-coupled, the dose dial sleeve (20) rotates in its threaded engagement (16, 23) with the housing (10) while the drive sleeve (50) is coupled to non-axial tracks (12) in the housing (10) to follow the pattern of these tracks (12) when moved back.

2. An injection device (1 ) according to claim 1 , wherein a coupling sleeve (30) is provided between the drive sleeve (50) and the dose dial sleeve (20) and which coupling sleeve (30) is forced to rotate in the track (12) during dosing.

3. An injection device (1 ) according to claim 2, wherein the coupling sleeve (3) is biased by a metal spring (40) towards a position in which it engages the dose dial sleeve (20).

4. An injection device (1 ) according to claim 3, wherein a cup shaped End-of-Content element (90) is threadely engaged with the dose dial sleeve (20).

5. An injection device (1 ) according to claim 4, wherein the cup shaped End-of-Content element (90) has longitudinal openings to allow arms (42) on the metal spring (40) to engage guiding tracks (12) in the housing (10).