SYSTEM FOR A DRUG DELIVERY DEVICE AND DRUG DELIVERY DEVICE

Abstract

The present disclosure refers to a system for a drug delivery device comprising a housing and a cartridge holder which may contain a cartridge filled with a medicament. The housing and the cartridge holder comprise a coding interface for dedicating a certain cartridge to a certain housing and a bayonet type attachment interface for releasably attaching the cartridge holder to the housing by an attachment movement comprising a first stage and a second stage. The system further comprises at least one compliant spring member arranged and designed such that it is strained during the first and/or the second stage of the attachment movement at least if the housing coding element does not match the holder coding element, and wherein the compliant spring member is arranged and designed to move the cartridge holder relative to the housing in a direction contrary to the attachment movement when relaxing.

Claims

1-15. (canceled)

16. A system for a drug delivery device comprising: a housing comprising at least one housing coding element selected from a group of at least two different housing coding elements; a cartridge holder comprising at least one holder coding element selected from a group of at least two different holder coding elements, wherein the cartridge holder is releasably attachable to the housing when the housing coding element of the housing matches with the holder coding element of the cartridge holder, whereas a full attachment of the cartridge holder to the housing is prevented when the housing coding element of the housing does not match with the holder coding element of a cartridge holder, wherein the cartridge holder is releasably attachable to the housing by at least one bayonet type attachment interface through an attachment movement comprising a first stage and a second stage, wherein the first stage comprises at least an axial movement component of the cartridge holder relative to the housing, and the second stage comprises at least a rotational movement component of the cartridge holder relative to the housing; and at least one compliant spring member arranged and designed such that it is strained during the first stage and/or the second stage of the attachment movement at least when the housing coding element does not match the holder coding element, wherein the compliant spring member is arranged and designed to move the cartridge holder relative to the housing in a direction contrary to the attachment movement when the compliant spring member is relaxing.

17. The system according to claim 16, wherein the at least one compliant spring member is a spring washer.

18. The system according to claim 17, wherein when a cartridge is retained in the cartridge holder: the spring washer is arranged in the housing so as to exert a force on the cartridge, and the cartridge holder is fully attached to the housing to secure the cartridge against an axial movement with respect to the cartridge holder.

19. The system according to claim 17, wherein the spring washer comprises fixing elements extending in an axial direction for fixing the spring washer within the housing.

20. The system according to claim 17, wherein at least one rib is formed on an inner wall of the cartridge holder, wherein the at least one rib is located so that, when the housing coding element does not match the holder coding element, at least at an end of the first stage of the attachment movement, an end surface of the at least one rib engages and compresses the spring washer.

21. The system according to claim 20, wherein the at least one rib is located in the cartridge holder such that the at least one rib does not compress the spring washer when the housing coding element of the housing matches with the holder coding element of the cartridge holder.

22. The system according to claim 16, wherein the at least one compliant spring member comprises at least one compliant region of the cartridge holder which is, at least at an end of the first stage of the attachment movement, elastically deformable by an engagement of the housing coding element and the holder coding element when if the housing coding element does not match the holder coding element.

23. The system according to claim 22, wherein the at least one compliant region of the cartridge holder comprises an axially extending slot in the cartridge holder.

24. The system according to claim 22, wherein the at least one compliant region of the cartridge holder comprises a circumferentially extending slot in the cartridge holder.

25. The system according to claim 16, wherein the at least one compliant spring member comprises at least one compression spring having a distal end attached to or abutting the cartridge holder, wherein at least at an end of the first stage of the attachment movement, the compression spring is elastically deformable by engagement of its opposite proximal end with the housing or with a component retained in the housing.

26. The system according to claim 25, wherein the at least one compression spring is configured as a metal wire-formed compression spring, a metal pressing, or a plastic molding.

27. The system according to claim 25, wherein at least at an end of the first stage of the attachment movement, the compression spring is elastically deformable by engagement of an opposite proximal end of the compression spring with a spring washer as the component is retained in the housing.

28. The system according to claim 27, wherein a stiffness of the spring washer is higher than a stiffness of the at least one compression spring.

29. The system according to claim 16, wherein the housing coding element and the holder coding element form a ramp interface, and wherein the second stage of the attachment movement is defined or governed by the ramp interface.

30. The system according to claim 16, wherein the bayonet type attachment interface is configured such that when the cartridge holder is attached to the housing, the cartridge holder is moved relative to the housing during the second stage of the attachment movement an axial distance in a second stage axial direction opposite to a direction of the axial movement component of the first stage.

31. The system according to claim 30, wherein the housing coding element and the holder coding element form a ramp interface, and wherein matching of the housing coding element of the housing with the holder coding element of the cartridge holder is defined by a slope of the ramp interface being equal to a slope defined by the axial distance of the second stage.

32. A drug delivery device comprising: a cartridge containing a medicament; a housing comprising at least one housing coding element selected from a group of at least two different housing coding elements; a cartridge holder holding the cartridge and comprising at least one holder coding element selected from a group of at least two different holder coding elements, wherein the cartridge holder is releasably attachable to the housing when the housing coding element of the housing matches with the holder coding element of the cartridge holder, whereas a full attachment of the cartridge holder to the housing is prevented when the housing coding element of the housing does not match with the holder coding element of a cartridge holder, wherein the cartridge holder is releasably attachable to the housing by at least one bayonet type attachment interface through an attachment movement comprising a first stage and a second stage, wherein the first stage comprises at least an axial movement component of the cartridge holder relative to the housing, and the second stage comprises at least a rotational movement component of the cartridge holder relative to the housing; and at least one compliant spring member arranged and designed such that it is strained during the first stage and/or the second stage of the attachment movement at least when the housing coding element does not match the holder coding element, wherein the compliant spring member is arranged and designed to move the cartridge holder relative to the housing in a direction contrary to the attachment movement when the spring member is relaxing.

33. The drug delivery device according to claim 32, wherein the at least one compliant spring member is a spring washer, wherein the spring washer is arranged in the housing so as to exert a force on the cartridge, and wherein the cartridge holder is fully attached to the housing to secure the cartridge against an axial movement with respect to the cartridge holder.

34. The drug delivery device according to claim 33, wherein at least one rib is formed on an inner wall of the cartridge holder, wherein the at least one rib is located so that, when the housing coding element does not match the holder coding element, at least at an end of the first stage of the attachment movement, an end surface of the at least one rib engages and compresses the spring washer.

35. The drug delivery device according to claim 32, wherein the at least one compliant spring member comprises at least one compliant region of the cartridge holder which is, at least at an end of the first stage of the attachment movement, elastically deformable by an engagement of the housing coding element and the holder coding element when the housing coding element does not match the holder coding element.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0066] FIG. 1 shows detailed section views of a range of dedicated cartridge holder components (only one of which is compatible with the housing component);

[0067] FIG. 2 shows a known cartridge holder;

[0068] FIG. 3 shows a section through a system of a first embodiment of the present disclosure, in which the cartridge holder is located in the blocking engagement position with respect to an incompatible housing;

[0069] FIG. 4 shows the cartridge holder of a second embodiment, showing compliant regions formed by slots;

[0070] FIG. 5 is an enlarged sectional view of the cartridge holder of the second embodiment;

[0071] FIG. 6 shows the cartridge holder of a third embodiment, showing compliant regions formed by slots;

[0072] FIG. 7 is an enlarged sectional view of the cartridge holder of the third embodiment;

[0073] FIG. 8 shows the cartridge holder of a fourth embodiment containing a compression spring;

[0074] FIG. 9 is a partially enlarged sectional view through the system of the fourth embodiment, in which the cartridge holder is located in the blocking engagement position with respect to an incompatible housing; and

[0075] FIG. 10 is a partially enlarged sectional view through the system of the fourth embodiment, in which the cartridge holder is located in the fully engaged position with respect to a compatible housing.

DETAILED DESCRIPTION

[0076] Referring to FIG. 1, a cartridge holder dedication system is shown which is based on the principle described in WO 2020/016162 A1 to which reference is made. This system comprises the combination of a pen injector mechanism housing 1 and a cartridge holder 2 which comprise interfaces adapted to each other. The housing 1 may be an outer housing or an inner housing of a drug delivery device. The cartridge holder may comprise a cartridge (not shown in FIG. 1) filled with a medicament. There may be a set of similar cartridge holders 2a to 2g and a set of similar housings 1 (only one is shown in FIG. 1) with the interfaces adapted such that only a certain cartridge holder 2a fits into and is compatible with a certain housing 1. The other cartridge holders 2b to 2g are not compatible with housing 1 as indicated by the “X” in FIG. 1.

[0077] The example shown in FIG. 1 is based on the use of a common bayonet attachment geometry for all variants, i.e. the housing 1 has a bayonet feature, here a bayonet slot or track 3, and all cartridge holders 2a to 2g have the identical mating counter bayonet feature, here bayonet protrusions 4 or keys (see FIGS. 2, 4, 6 and 8). The bayonet track 3 has at least two distinct portions, namely a first steep helical part of the bayonet track and a second, e.g. subsequent, flatter helical part of the bayonet track. As a consequence, an attachment movement of the cartridge holder 2a to 2g relative to the housing 1 comprises a first stage and a second stage, with the first stage comprising more axial than rotational movement of the bayonet protusions 4 in the first steep helical part of the bayonet track 3 and the second stage comprising a more rotational than axial movement of the bayonet protusions 4 in the second flatter helical part of the bayonet track 3. The slope of the second flatter helical part of the bayonet track 3 may be such that during the second stage the bayonet protusions 4 are slightly moved in an opposite axial direction compared with the first stage movement. In any case the first stage comprises at least an axial movement component of the cartridge holder 2a to 2g relative to the housing 1 and the second stage comprises at least a rotational movement component of the cartridge holder relative to the housing.

[0078] In this system, dedication is achieved by having a range of different coding elements in the form of ramp feature geometries moulded onto the end surface of the cartridge holder component 2a to 2g (holder coding element 5) and a range of corresponding different receiving features (housing coding element 6) moulded into the housing component 1 of the pen mechanism. If the ramps 5, 6 on the cartridge holder 2a to 2g and on the housing 1 are compatible then the components will assemble correctly to the end location of the bayonet track 3. If however, the ramps 5, 6 are incompatible, then they will block full engagement of the cartridge holder bayonet protrusions 4, as shown in FIG. 1.

[0079] As can be seen in FIG. 1, the bayonet protrusions 4 of the cartridge holder 2a to 2g are permitted to partially engage with the bayonet tracks 3 of the housing 1 before the blocking occurs, and so in some circumstances the user may be confused as to whether the cartridge holder 2a to 2g and pen mechanism housing 1 are compatible or not.

[0080] The present disclosure as depicted in FIGS. 3 to 10 provides additional tactile and visual feedback to the user when blocking occurs, such that it is more obvious when attachment of an incompatible cartridge holder/housing pairing is attempted. This is achieved by locating a compliant spring member (described below in more detail) between the cartridge holder 2a to 2g and pen injector mechanism housing 1 that is loaded as the cartridge holder 2a to 2g is attached to the pen injector.

[0081] If an incompatible pairing is attempted, then blocking will occur on the steep helical part of the bayonet track 3 as a result of engagement between the incompatible ramp features 5, 6. In this circumstance, the compliant spring located between the cartridge holder 2a to 2g and the pen injector mechanism housing 1 will be loaded, applying a force and/or torque on to the cartridge holder 2a to 2g that urges the cartridge holder back out of engagement.

[0082] If the user releases their grip on the cartridge holder 2a to 2g then the cartridge holder will, under the force/torque applied by the compliant spring member, move back up the bayonet track 3 and away from the blocking location. This spring force, and the resultant movement of the cartridge holder 2a to 2g when it is released, provides an indication to the user that the cartridge holder 2a to 2g has not reached the correct attachment location and thus is not compatible with the pen injector mechanism housing 1.

[0083] If the user attaches a cartridge holder 2a that is compatible with a pen injector mechanism housing 1 then the compliant spring element between the cartridge holder and pen injector mechanism housing is configured such that it will either not be loaded during attachment, or any loading does not compromise the correct attachment or function of the pen. The cartridge holder 2a engages fully with the corresponding bayonet track 3 of the mechanism. In the fully assembled location, the cartridge holder 2a is preferably located in a region of the bayonet track 3 where it is retained by a detent and there is no resultant force that will cause it to disassemble from the pen mechanism.

[0084] The present disclosure is applicable to various types of drug delivery devices. As a non limiting example, a drug delivery device of the type known from WO 2014/033195 A1 is shown in FIG. 3. This device has a distal end (left end in FIG. 3) and a proximal end (right end in FIG. 3). The drug delivery device comprises an outer housing part 8, a spring washer 7, the housing 1 which is an inner body in this example, a piston rod 9, a driver 10, a display member or number sleeve 11, a button 12, the cartridge holder 2 for receiving a cartridge 13, a clutch 14 and a pressure foot 15.

[0085] FIG. 3 shows a first embodiment of the present disclosure, which uses the spring washer 7 to provide the compliant spring member. In known devices such a spring washer 7 may be provided as a pressed metal cartridge bias spring to hold a cartridge 13 in a predefined position with respect to the cartridge holder 2. These spring washers 7 may be located directly or indirectly fixed within the pen injector mechanism housing, e.g. by means of axially extending fixing elements. For example, in FIG. 3 the spring washer 7 is fixed to the outer housing 8 via the inner housing 1. FIG. 3 shows a section through the drug delivery device assembly in which the cartridge holder 2 is located in the blocking engagement position with respect to an incompatible pen injector mechanism housing 1.

[0086] The enlarged lower image of FIG. 3 shows a region of the sectional view of the upper image. In the enlarged view it can be seen that at least one rib 16 is formed on the inner wall of the cartridge holder component 2. This rib 16 is located so that when the blocking ramp features 5, 6 between the cartridge holder 2 and pen mechanism housing 1 are engaged, the proximal end surface of the rib 16 has engaged and slightly compressed the spring washer 7. This applies a small axial force to the cartridge holder 2, which urges the part back out of engagement. If the user releases their grip on the cartridge holder 2, then the cartridge holder 2 will, under the force applied by the spring washer 7, move back up the bayonet track 3 and away from the blocking location.

[0087] This arrangement has the advantage that the existing spring washer 7 in the pen injector mechanism is used as the compliant spring member. Because the spring is a pressed metal component, it is not likely to be susceptible to creep or plastic deformation during the use life.

[0088] The ribs 16 are located in or on the bore of the cartridge holder 2 such that they do not compress the spring washer 7 when a cartridge holder 2 is fully attached to a compatible pen injector mechanism housing. This can be achieved because the rotational position of the cartridge holder 2 with respect to the pen mechanism is different when it is fully attached (to a compatible pen) compared with when it is in the blocked position (with an incompatible pen). In the fully attached location, the ribs 16 of the cartridge holder 2 do not coincide with the peaks of the spring washer 7 in the pen and so the spring washer 7 engages with the rim of the cartridge 13 to keep it correctly biased during use.

[0089] FIGS. 4 and 5 show a second embodiment of the present disclosure which uses compliant regions 17 of the cartridge holder moulding to store and release torque to move the cartridge holder 2 back up the bayonet track 3, away from the blocking location when the user releases their grip. These compliant regions 17 are created by slots 18 that are formed at the proximal end of the cartridge holder 2. In FIGS. 4 and 5, the slots 18 extend mainly axially.

[0090] As can be seen in FIG. 5, when torque is applied by the user to attempt to screw the cartridge holder 2 past the blocking location, this is reacted as a force/torque between the ramps 5 of the cartridge holder 2 and the corresponding features 6 of the inner housing 1. Owing to the slots 18 formed in the end of the cartridge holder 2, this component is somewhat elastically compliant and acts as a spring under the user applied torque. When the user releases the cartridge holder 2 in the blocked location, any energy stored in the cartridge holder 2 by its' elastic deflection will be released, causing it to unwind a small distance back up the bayonet track 3.

[0091] FIGS. 6 and 7 show a third embodiment of the present disclosure, which uses differently configured compliant elements 19 of the cartridge holder moulding to provide the force which moves the cartridge holder 2 back up the bayonet track 3, away from the blocking location when the user releases their grip. These compliant elements 19 are created in the ramp features 5 of the cartridge holder 5 by the introduction of slots 20 that are formed in the part.

[0092] As can be seen in FIG. 7, when torque is applied by the user to attempt to screw the cartridge holder 2 past the blocking location, this is reacted as a force on the compliant elements 19 formed by the slots 20 in the end of the cartridge holder 2. The compliant elements 19 are elastically compliant and act as cantilever type springs under the user applied torque. When the user releases the cartridge holder 2 in the blocked location, any energy stored in the compliant elements 19 of the cartridge holder 2 by its' elastic deflection will be released, causing it to unwind a small distance back up the bayonet track 3.

[0093] FIGS. 8 to 10 show a fourth embodiment of the present disclosure, which uses a separate additional spring member 21 to provide force that moves the cartridge holder 2 back up the bayonet track 3, away from the blocking location when the user releases their grip. The spring member 21 is a part of the cartridge holder assembly and can be configured as a metal wire-formed compression spring. As an alternative, the spring member may be a metal pressing or a plastic moulding (not shown). FIG. 8 shows a cartridge holder assembly of the fourth embodiment of the disclosure, in which a wire-formed compression spring 21 is located in the proximal end of the assembly. FIGS. 9 and 10 both show the identical drug delivery device but with different cartridge holders. In addition, FIG. 9 shows the drug delivery device rotated by 90° about the longitudinal axis of the device compared with FIG. 10.

[0094] The compression spring 21 is designed and located so that it makes contact with the spring washer 7 of the pen injector mechanism during attachment of the cartridge holder 2. The compression spring 21 in the cartridge holder assembly provides a light force when the cartridge holder 2 is located in the blocked position with respect to an incompatible pen injector mechanism, sufficient only to move the cartridge holder 2 back up the bayonet track 3, away from the blocking location when the user releases their grip. In this example, the compression spring 21 in the cartridge holder assembly is not stiff enough to cause significant deflection of the spring washer 7 located in the pen mechanism.

[0095] FIG. 9 shows sectional views of the fourth embodiment, in which a cartridge holder 2 is located in the blocking position with respect to an incompatible pen injector mechanism. As can be seen in FIG. 9, the compression spring member 21 of the cartridge holder is slightly compressed by its' contact with the spring washer 7 of the pen injector under a user applied torque. When the user releases the cartridge holder 2 in this location, energy stored in the compression spring 21 by elastic deflection will be released, causing the cartridge holder 2 to unwind a small distance up the bayonet track 3.

[0096] If the cartridge holder 2 of the fourth embodiment is attached to a compatible pen injector mechanism, the compression spring member 21 will be deflected by contact with the spring washer 7 owing to its much lower stiffness. This means that the spring washer 7 is still able to perform its key function of engaging and biasing the cartridge 13 forwards onto its datum contact surface with the cartridge holder 2.

[0097] This is shown in FIG. 10, where the cartridge holder 2 has been correctly (fully) attached to a compatible mechanism housing 1 that is suitable for a 1.5 mL cartridge 13.

REFERENCE NUMERALS

[0098] 1 housing (inner body)
2, 2a-2g cartridge holder
3 bayonet track
4 bayonet protrusion
5 holder coding element (ramp)
6 housing coding element (ramp)
7 spring washer
8 outer housing
9 piston rod
10 driver
11 number sleeve
12 button
13 cartridge
14 clutch
15 pressure foot
16 rib
17 compliant region
18 slot
19 compliant region
20 slot
21 spring