Description
SYSTEM FOR A DRUG DELIVERY DEVICE AND DRUG DELIVERY DEVICE
The present invention is generally directed to a system for drug delivery device, e.g. an
injection device for selecting and dispensing a number of user variable doses of a
1 0 medicament. The invention is further directed to a drug delivery device.
Pen type drug delivery devices have application where regular injection by persons without
formal medical training occurs. This may be increasingly common among patients having
diabetes where self-treatment enables such patients to conduct effective management of
15 their disease. In practice, such a drug delivery device allows a user to individually select and
dispense a number of user variable doses of a medicament. The present invention is further
directed to so called fixed dose devices which only allow dispensing of a predefined dose
without the possibility to increase or decrease the set dose.
20 There are basically two types of drug delivery devices: resettable devices (i.e., reusable) and
non-resettable (i.e., disposable). For example, disposable pen delivery devices are supplied
as self-contained devices. Such self-contained devices do not have removable pre-filled
cartridges. Rather, the pre-filled cartridges may not be removed and replaced from these
devices without destroying the device itself. Consequently, such disposable devices need not
25 have a resettable dose setting mechanism.
The present invention is mainly applicable for (but not limited to) reusable devices, where a
single drive mechanism which may be housed in a housing of the drug delivery device is
used in conjunction with several cartridges or ampules to dispense drug contained in the
30 cartridge or ampule from the device. An example of such a reusable drug delivery to which
the present invention is applicable is known from WO 2014/033195 A1.
In such devices, usually a cartridge holder of the device is releasably connected or attached
to the housing and can be removed or detached from the housing to replace a used
35 cartridge. For doing so, the cartridge holder is disconnected from the housing, the used
cartridge is removed from the holder and replaced with a new cartridge which is inserted into
the cartridge holder, where the cartridge holder is again attached to the housing and the
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device is ready to be used again to dispense drug from the new cartridge. The system of the
present invention comprises such a combination of a housing and a cartridge holder.
In such a system a range of dedicated cartridge holders may be used in conjunction with a
5 set of different dedicated reusable pen injectors. Such dedication may be required for
example where different medication cartridge sizes are used (e.g. 1.5ml and 3ml), or where
the cartridges contain different concentrations of medication (e.g. U100 and U300). In this
scenario a range of different pen injector mechanisms may be needed to deliver the
medication because e.g. the piston rod travel per unit increment of medication will likely
1 0 change for the different cartridge or medication types. Thus, systems of this kind have the
risk that a cartridge containing a drug for which the mechanism of the drug delivery device is
not specifically designed, i.e. a wrong drug, can be inserted into the cartridge holder and the
user does not realize that he or she has put the wrong drug cartridge into the cartridge
holder. This mistake may be lethal for the user and is also likely to occur as cartridges with
15 different drugs may look highly similar.
To help to prevent a mix-up, a dedication system is known in which different cartridges are
supplied to the market pre-assembled (irremovably) within dedicated cartridge holders.
These dedicated cartridge holders are designed only to engage correctly (fully) with a
20 compatible pen mechanism. Such a cartridge holder dedication system is described in
25
WO 2020/016162 A 1 disclosing a system comprising a housing and a cartridge holder with a
bayonet type attachment interface for releasably attaching the cartridge holder to the housing
and a coding interface that ensures that only matching pairs of housings and cartridge units
can be connected.
For example, the system uses a common bayonet attachment geometry for all variants. In
this system, dedication is achieved by having a range of different ramp feature geometries
moulded onto the end surface of the cartridge holder and a range of corresponding different
receiving features moulded into the housing, e.g. into an inner body component of the pen
30 mechanism. If the ramps on the cartridge holder and inner body are compatible then the
components will assemble correctly to the end location of the bayonet track. If however, the
ramps are incompatible, then they will block full engagement of the cartridge holder bayonet.
A potential disadvantage of the dedication system described in WO 2020/016162 A 1 may be
35 that the bayonet features of the cartridge holder are permitted to partially engage with the
bayonet tracks of the housing or inner body before the blocking occurs, and so in some
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circumstances the user may be confused as to whether the cartridge holder and pen
mechanism are compatible or not.
US 2014/052075 A 1 discloses a drug delivery device comprising a cartridge holder and a
5 housing, wherein the cartridge holder is provided with a coding element which interacts with
a counterpart of an interaction member which is not part of the housing. The interaction
member needs to be rotatable with respect to the longitudinal axis of the device, i.e. with
respect to the housing. This interaction member is merely a connecting element without any
coding function.
10
WO 2008/07 4897 A 1 discloses a container and a dosing assembly comprising a housing.
The container comprises coding projections and the housing comprises a coding groove. The
interaction of the coding projection and the coding groove ensures that only predetermined
containers are fastened to corresponding dosing assemblies. The attachment of the
15 container and the housing is realized by a fastening projection interacting with a fastening
groove and a retaining projection interacting with a retaining groove. Further, the container is
fastened to the assembly by an initial axial movement followed by a combined axial and
rotational movement. For resetting of the device, a spring biases a coupling mechanism
towards a distal position when no container is fastened to the housing. A push member
20 biased by the spring exerts a distal force to a cartridge accommodated into a cartridge
holder.

Claims
1. A system for a drug delivery device comprising:
- a housing (1, 8) comprising at least one housing coding element (6) selected from a group of
at least two different housing coding elements,
- a cartridge holder (2, 2a) comprising at least one holder coding element (5) selected from a
group of at least two different holder coding elements, wherein the cartridge holder (2, 2a) is
releasably attachable to the housing (1, 8) if the housing coding element (6) of the housing (1,
8) matches with the holder coding element (5) of the cartridge holder (2, 2a), whereas if the
housing coding element (6) of the housing (1, 8) does not match with the holder coding element
(6) of a cartridge holder (2b, 2c, 2d, 2e, 2f, 2g) full attachment of the cartridge holder (2b, 2c,
2d, 2e, 2f, 2g) to the housing (1, 8) is prevented,
wherein the housing (1, 8) and the cartridge holder (2, 2a) comprise at least one bayonet type
attachment interface (3, 4) for releasably attaching the cartridge holder (2, 2a) to the housing (1,
8) by 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 (2, 2a) relative to
the housing (1, 8) and the second stage comprises at least a rotational movement component of
the cartridge holder (2, 2a) relative to the housing (1, 8),
wherein the system further comprises at least one compliant spring member (7, 17,19, 21)
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 (6) does not match the holder
coding element (5), and wherein the compliant spring member (7, 17, 19, 21) is arranged and
designed to move the cartridge holder (2, 2a) relative to the housing (1, 8) in a direction contrary
to the attachment movement when relaxing.
2. The system according to claim 1, wherein the at least one compliant spring member is a
spring washer (7) arranged in the housing (1, 8) so as to exert a force on a cartridge (13) if the
cartridge is retained in the cartridge holder (2, 2a) and the cartridge holder (2, 2a) is fully
attached to the housing (1, 8) to secure the cartridge (13) against axial movement with respect
to the cartridge holder (2, 2a).
3. The system according to claim 2, wherein the spring washer (7) comprises fixing
elements extending in an axial direction for fixing the spring washer (7) within the housing (1, 8).
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4. The system according to claim 2 or 3, wherein at least one rib (16) is formed on an inner
wall of the cartridge holder (2, 2a), which at least one rib (16) is located so that, if the housing
coding element (6) does not match the holder coding element (5), at least at the end of the first
stage of the attachment movement, an end surface of the at least one rib (16) engages and
compresses the spring washer (7).
5. The system according to claim 4, wherein the at least one rib (16) is located in the
cartridge holder (2, 2a) such that it does not compress the the spring washer (7) if the housing
coding element (6) of the housing (1, 8) matches with the holder coding element (5) of the
cartridge holder (2, 2a).
6. The system according to claim 1, wherein the at least one compliant spring member
comprises at least one compliant region ( 17, 19) of the cartridge holder (2, 2a) which is, at least
at the end of the first stage of the attachment movement, elastically deformable by engagement
of the housing coding element (6) and the holder coding element (5) if the housing coding
element (6) does not match the holder coding element (5).
7. The system according to claim 6, wherein the at least one compliant region (17) of the
cartridge holder (2, 2a) comprises an axially extending slot (18) in the cartridge holder (2, 2a).
8. The system according to claim 6, wherein the at least one compliant region (19) of the
cartridge holder (2, 2a) comprises a circumferentially extending slot (20) in the cartridge holder
(2, 2a).
9. The system according to claim 1, wherein the at least one compliant spring member
comprises at least one compression spring (21) having a distal end attached to or abutting the
cartridge holder (2, 2a), wherein the compression spring (21) is, at least at the end of the first
stage of the attachment movement, elastically deformable by engagement of its opposite
proximal end with the housing (1, 8) or a component (7) retained in the housing (1, 8).
10. The system according to claim 9, wherein the at least one compression spring (21) is
configured as either a metal wire-formed compression spring, a metal pressing or a plastic
moulding.