BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an assembly for a medication delivery device. The present invention further relates to a medication delivery device. In particular, the invention relates to single-shot variable-dose medication delivery device.

In a single-shot variable-dose medication delivery device a dose may be displaced with respect to a body of the device in a distal direction by a piston rod. Thereby, the user settable dose of a medication may be expelled from the device. After delivery of the single dose, the device may be locked for preventing a further dose setting or dose delivery operation.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an assembly for a medication delivery device having improved properties, e.g., increased user comfort, increased safety, lower error-proneness and/or reduced manufacturing costs. Furthermore, it is an object of the invention to provide a piston rod, also commonly referred to as a plunger, for an improved medication delivery device.

This object may be achieved by the subject matter described herein.

One aspect relates to an assembly for a medication delivery device.

The assembly is configured to perform a dose setting operation. The assembly comprises a dose setting sleeve and a drive sleeve. The assembly further comprises a piston rod and a body. The dose setting sleeve is adapted and arranged to be rotated with respect to the body for setting the dose of the medication. The drive sleeve is configured such that the piston rod is pushed in a distal direction relative to the body by the drive sleeve when the drive sleeve moves in the distal direction relative to the body. The dose setting sleeve comprises a first dosing track having a first length and defining a first size of a dose and at least a second dosing track having a second length and defining a second size of a dose, wherein the first length is different from the second length and the first size is different from the second size. The drive sleeve comprises an engagement feature configured to engage with one of the dosing tracks. The assembly is configured such that the dose setting operation comprises a first step wherein the engagement feature is aligned with one of the tracks and a second step wherein the engagement feature is moved along the track.

Accordingly, both of the dosing tracks and the engagement feature are arranged on sleeves which are movable relative to the body, i.e., the drive sleeve and the dose setting sleeve. The assembly may be configured such that the dose setting sleeve has to be rotated relative to the body to set a dose and that the drive sleeve has to be moved axially relative to the body to dispense the dose. Thereby, the security is increased and the danger of an accidental misuse can be reduced as it is ensured that two separate components have to be operated by a user for dose setting and dose dispensing.

The dose setting operation may be defined as an operation wherein the device or the assembly is prepared to dispense a dose of defined size wherein the size of said dose is determined during the dose setting operation.

The dosing tracks may allow to guide a movement of the drive sleeve. Thereby, the stability of the device may be improved. In particular, as the engagement feature is engaged with one of the dosing tracks during the second step of the dose setting operation, the danger of damaging the assembly, for example, causing the set dose to be changed, due to an impact during the dose setting operation is significantly reduced. Such an impact may be caused, for example, by a fall, i.e., when a user drops the medication delivery device comprising the assembly. Accordingly, the assembly provides an increased stability and prevents damaging the device due to misuse.

Moreover, the dosing tracks may be configured to ensure that only discrete doses can be set. Thereby, the dose setting operation can be facilitated for the user. In particular, users having impaired vision or reduced dexterity require a device that is easy to operate. The design of the assembly comprising dosing track corresponding to discrete doses of a medication may help the user to set the correct dose. For example, the assembly may be configured to enable the user to set a discrete dose by providing audible counting clicks so that the user does not have to refer to a dosing scale. Accordingly, the assembly may provide an improved usability.

The assembly may be adapted and arranged to be integrated/to be used in the medication delivery device. This means that the assembly may provide specific structural and functional features making the assembly suitable for the medication delivery device. The medication delivery device may be a pen-type device, e.g., a pen-type injector or a pen-type pre-filled syringe.

The medication delivery device may be adapted and arranged to dispense a dose, in particular exactly one dose, i.e., a single dose, of a medication. The device may be a single-shot or single-use device. The medication may be a fluid. The single dose of the medication may be chosen or set by a user. The single dose of medication may, thus, be variable. After delivery of the single dose of the medication, the medication delivery device may be discarded. In particular, further use of the device for setting and dispensing a further dose of the device may be impossible.

The dose setting sleeve may be a component that is operated by a user either directly or indirectly to set a dose. The dose setting sleeve may be adapted and arranged to be rotated with respect to a body for setting the dose of the medication. The dose setting sleeve may be gripped for being rotated by the user. The dose setting sleeve may be tubular.

The drive sleeve may be a component that is operated by a user either directly or indirectly for delivering a dose. The drive sleeve may also be operated by a user either directly or indirectly for setting a dose. In particular, the drive sleeve may be moved in a proximal direction with respect to the body or the dose setting sleeve in a second step of the dose setting operation. The drive sleeve may be fixed to an end cap of the assembly. The end cap may be configured to be pressed by a user for delivering the dose. The drive sleeve may be non-releasably fixed to the end cap by fixing elements. Alternatively, the drive sleeve and the end cap may be unitarily formed. The drive sleeve may interact directly with a piston rod of the assembly. In particular, the drive sleeve may be configured such that the piston rod is pushed in a distal direction by the drive sleeve when the drive sleeve moves in the distal direction.

The term “distal” or “distal end” refers to that end of the device or a component that is closest to a dispensing end of the device. The term “proximal” or “proximal end” refers to that end of the device or a component that is furthest away from the dispensing end of the device. The term “distal direction” refers to the direction from the proximal end to the distal end of the device or a component. The term “proximal direction” refers to the opposite direction, i.e., the direction from the distal end to the proximal end.

The dosing tracks may be adapted and arranged to receive the engagement feature. The dosing tracks may be grooves or slots. The dosing tracks may be configured to guide a movement of the drive sleeve by constraining the movement of the engagement feature.

The length of a dosing track may correspond to the distance by which the piston rod is displaced in a dose dispensing operation when the engagement feature has previously been received in the dosing track. The length of a dosing track may correspond to the distance by which a dose is displaced during the dose dispensing operation when the engagement feature has previously been received in the dosing track. The dosing tracks may define discrete doses that a settable by the assembly.

The engagement feature may be any element suitable to be received and guided in a track. For example, the engagement feature may be a protrusion. The engagement feature may be a follower. In particular, the engagement feature may comprise two followers.

Each of the first step and the second step of the dose setting operation may be initiated by a manual action performed by the user. For example, the first step may be initiated by the user rotating the dose setting sleeve which comprises the dosing tracks. The second step may be initiated by the user pulling the drive sleeve in the proximal direction.

The dose setting sleeve may be rotated relative to the drive sleeve during the first step of the dose setting operation. Thereby, the relative radial position of the dosing tracks with respect to the engagement feature may be amended as the dosing tracks are arranged on the dose setting sleeve and the engagement feature is arranged on the drive sleeve.

The drive sleeve may be moved purely linear relative to the dose setting sleeve during the second step of the dose setting operation. In particular, the drive sleeve may be moved purely linear in the proximal direction relative to the dose setting sleeve during the second step of the dose setting operation. Due to the relative movement of the drive sleeve with respect to the dose setting sleeves, the engagement feature may be moved along one of the dosing tracks.

According to one embodiment, the assembly may be configured such that each of the first step and the second step of the dose setting operation is initiated by a user-operated action. In particular, the assembly may comprise a body, wherein the assembly is configured such that the first step of the dose setting operation is initiated by a user rotating the dose setting sleeve relative to the body, and the second step of the dose setting operation is initiated by a user pulling the drive sleeve relative to the body in the proximal direction. The body may be designed to enable a safe and comfortable handling of the medication delivery device. The body may be configured to house, fix, protect and guide inner components of the medication delivery device, e.g., a piston rod, a dose setting sleeve and/or a drive sleeve. Preferably, the body limits or prevents the exposure of the inner components and/or the medication to contaminants such as liquid, dirt or dust. The body may be a unitary or multipart component.

According to one embodiment, the assembly may be configured such that the second step of the dose setting operation is prevented if the engagement feature is not aligned with one of the dosing tracks. In other words, the second step can only be initiated if the engagement feature is aligned with one of the dosing tracks. Thereby, it may be ensured that only discrete dose sizes can be set wherein the dose sizes are defined by the lengths of the dosing tracks. If the engagement feature is not aligned with a dosing track and the user tries to pull the drive sleeve in the proximal direction, a movement of the drive sleeve may be blocked by the engagement feature abutting the dose setting sleeve.

According to one embodiment, the assembly may be configured to perform a dose dispensing operation wherein a dose of a medication is dispensed from the medication delivery device. The assembly may be configured such that, during the first step of the dose setting operation, a size of the dose which is dispensed in the dose dispensing operation is selected by aligning the engagement feature with one of the tracks, and the assembly may be configured such that, during the second step of the dose setting operation, the assembly is prepared to dispense a dose of the size selected in the first step by moving the drive sleeve relative to the dose setting sleeve by a distance corresponding to length of the track to which the engagement feature has been aligned in the first step. In other words, the first step may serve the purpose to select the dose, i.e., to determine the size of the dose to be delivered later. The second step may serve the purpose to actually set the dose, i.e., to prepare the device for dispensing a dose of the previously selected size. By designing the assembly such that selecting and setting are performed in two separate steps, it can be ensured that, during the setting of the dose, a previously selected dose size cannot be amended. Thereby, the safety can be improved.

In particular, during the second step of the dose setting operation, a rotation of the dose setting sleeve relative to the drive sleeve may be prevented by the engagement of the engagement feature with one of the tracks. Thus, it may be prevented to amend the pre-selected dose during the second step.

According to one embodiment, the dose setting sleeve may comprise a third track having a third length and defining a third size of a dose, wherein the third length is different from the first length and the second length and the third size is different from the first size and the second size. The dose setting sleeve may comprise more than three dosing tracks.

According to one embodiment, the assembly may comprise a piston rod and a body, wherein the piston rod is adapted and arranged to be linearly moved in a distal direction with respect to the body for dispensing the medication, and wherein the drive sleeve is mechanically engaged with the piston rod such that a linear movement of the drive sleeve relative to the piston rod in a proximal direction is enabled and such that a linear movement of the drive sleeve relative to the piston rod in a distal direction is prevented. In particular, the drive sleeve and the piston rod may be mechanically engaged by a ratchet arm of the drive sleeve engaging ratchet teeth of the piston rod. The ratchet arm and the ratchet teeth may be adapted and arranged to enable a movement of the piston rod in the proximal direction relative to the drive sleeve and to prevent a movement of the piston rod in the distal direction relative to the drive sleeve.

The assembly may comprise a deflectable feature, wherein the assembly comprises a first stop face, wherein the assembly is configured to be transferred into a locked-out state by the deflectable feature overriding the first stop face, wherein in the locked-out state, any movement of the drive sleeve relative to the body is prevented, and wherein the assembly is configured such that, before setting a dose for the first time, the piston rod is arranged such that the piston rod prevents a deflection of the deflectable feature, thereby preventing the deflectable feature from overriding the first stop face.

The deflectable feature may be arranged on the drive sleeve.

The piston rod may comprise a section having a maximum radial extension, wherein the section having the maximum radial extension is aligned with the deflectable feature before a dose is set for the first time, thereby preventing the deflection of the deflectable feature.

The assembly may be configured such that the drive sleeve is moved in the proximal direction relative to the piston rod for setting a dose, thereby moving the section having the maximum radial extension away from the deflectable feature and, thus, allowing a deflection of the deflectable feature.

According to one embodiment, the assembly may be configured to perform a priming operation wherein a priming dose is dispensed from the device. The priming operation may have to be carried out before a dose setting operation can be performed for the first time. The priming operation may ensure that any tolerances due to manufacturing or assembling are removed. For example, a gap between the piston rod and the dose may be removed during the priming operation. Another possible function of the priming operation could be to remove any air bubbles in a syringe or a cartridge comprising the medication. In this case the device must be oriented needle upwards prior to conducting the priming stroke. The piston rod may be moved in the distal direction relative to the body during the priming operation.

The dose setting sleeve may comprise a priming track having a length which is shorter than the length of the dosing tracks of the dose setting sleeve wherein the priming track defines a size of a priming dose which has to be dispensed before a dose setting operation can be performed for the first time. The length of the priming track may correspond to the distance by which the piston rod is displaced during the priming operation. At the end of the priming operation, the engagement feature may be disengaged from the priming track. In an alternative design, the priming track may have the same length as one of the dosing tracks.

The device may be configured such that the engagement feature cannot re-enter the priming track after it has been disengaged from the priming track. For this purpose, the end of the priming track may be formed with a “one-way” feature. For example, the engagement feature may comprise a flexible protrusions and a bump or a detent may be formed as the one-way feature at the distal end of the priming track. The one-way feature may be arranged and designed to prevent the engagement feature from re-entering the priming track.

According to one embodiment, the priming operation may consist of a single manually-operated step. Said manually-operated step may be pushing the drive sleeve in the distal direction by a priming distance. Thus, the priming operation can easily be performed by any user, even by users suffering from impaired vision and/or reduced dexterity.

The assembly may be configured such that the user cannot avoid or forget priming as it is not possible to initiate a dose setting operation, e.g., by rotating the dose setting sleeve, until priming is completed. Thus, it may not be possible to forget to prime as an unprimed device cannot proceed to the next step.

According to one embodiment, the assembly may be configured such that, during the priming operation, the drive sleeve is moved relative to the dose setting sleeve either purely linear or helical in the distal direction.

If the drive sleeve is moved helical relative to the dose setting sleeve during the priming operation, the priming operation may not be a separate manually-operated operation. Instead, in this case, the priming operation may be performed automatically if a user performs the first step of a dose setting operation, i.e., if a user rotates the dose setting sleeve relative to the drive sleeve. Thereby, the number of user operated steps may be reduced, thus improving the usability of the device. The assembly is configured such that the user cannot avoid or forget priming as the priming operation is performed “automatically”, i.e., without the user being aware of it, as a part of the first step of the dose setting operation. As discussed above, even if the priming operation is a separate manually-operated operation, the device may be configured such that it is still not possible to forget to prime as a dose setting operation cannot be initiated in an unprimed device before priming.

A helical priming track may ensure that the dose setting sleeve can be rotated relative to the drive sleeve only in one rotational direction. It may not be possible to pull the drive sleeve in the proximal direction as long as the engagement feature is in the helical priming track.

The assembly may comprise a longitudinal axis. The longitudinal axis may be defined by a linear connection of a dispensing end of the device and an end opposite of the dispensing end. The longitudinal axis may be a symmetry axis of the device. The engagement feature may be a protrusion extending from the drive sleeve in a radial direction away from the longitudinal axis, wherein the tracks on the dose setting sleeve are formed by grooves or slots in the dose setting sleeve. A protrusion and slots or grooves configured to receive said protrusion may provide a simple and compact mechanism which ensures a good mechanical engagement and which is not prone to errors.

The assembly may have an unprimed state and a primed state, wherein the assembly is configured to be transferred from its unprimed state to its primed state by performing a priming operation, wherein the dose setting sleeve has to be rotated relative to the drive sleeve for setting a dose of a medication, wherein the drive sleeve is configured to move the piston rod in a distal direction relative to the body for dispensing the dose, wherein a rotation of the dose setting sleeve relative to the drive sleeve is prevented by a mechanical engagement of the drive sleeve and the dose setting sleeve in the unprimed state of the assembly, and wherein the mechanical engagement of the drive sleeve and the dose setting sleeve is released during the priming operation.

According to one embodiment, the first dosing track and the dosing second track may be parallel to the longitudinal axis. In other word, the dosing tracks may be linear. The dose setting sleeve may comprise further dosing tracks which may also be linear and which may differ from the first and the second dosing track in their length. Linear dosing tracks may provide a simple mechanism to guide a linear movement of the drive sleeve.

According to a further aspect, a medication delivery device is described. The medication delivery device may comprise the previously described assembly. The assembly may be integrated in the device or may be part of the device. The device may be a single-shot variable-dose device. The device may be supplied to the user in an unprimed state. Before the device is in a condition for setting the single dose of the medication, the user may have to prime the device. After delivery of the single dose of the medication, the device may be locked such that a further dose setting and dose delivery operation may be prevented. In this way, a user-friendly and safe device is provided which has a low number of components.

The medication delivery device may comprises a cartridge comprising a medication which is dispensed in a dose delivery operation by the assembly. Alternatively, the medication delivery device may be a syringe comprising a medication which is dispensed in a dose delivery operation by the assembly.

In the following text, a set of advantageous aspects is described. The aspects are numbered to facilitate referencing features of one aspect in other aspects. Features from the aspects are not only relevant in connection with the specific aspects they relate to but are also of relevance on their own.

The following aspects relate to a prime lock which ensures that a priming operation has to be performed before a dose setting operation and a dose delivery operation can be performed. Thereby, a high dose accuracy can be ensured as any assembly tolerances and/or any air bubble can be removed by performing the priming operation.

The aspects discussed in the following refer to embodiments wherein the prime lock which ensures that the priming operation has to be performed is provided by the dose setting sleeve and the drive sleeve. Thereby, the object is solved to provide an assembly for a medication delivery device with a prime lock which requires only a minimal number of components. In particular, the dose setting sleeve and the drive sleeve may be required for a dose dispensing mechanism anyway such that the prime lock does not increase the number of components.

The aspects 1 to 10 relate to an embodiment wherein the priming operation is user-operated and wherein the priming operation is a separate operation from the dose setting operation. The priming operation may be a “push-to-prime” operation wherein a user has to move the drive sleeve axially for the priming operation. The aspects 11 to 15 relate to an embodiment wherein the priming operation can occur during the first dose setting operation. The user action of rotating the dose setting sleeve can pull the drive sleeve, and thereby the piston rod, in the distal direction. Accordingly, the priming step can be completed as a part of a first step of setting a dose. This provides the advantage of a reduced number of user-operated steps.

1. Assembly for a medication delivery device,

wherein the assembly has an unprimed state and a primed state,

wherein the assembly is configured to be transferred from its unprimed state to its primed state by performing a priming operation,

wherein the assembly comprises a dose setting sleeve, a drive sleeve, a piston rod and a body,

wherein the dose setting sleeve has to be rotated relative to the drive sleeve for setting a dose of a medication,

wherein the drive sleeve is configured to move the piston rod in a distal direction relative to the body for dispensing the dose,

wherein a rotation of the dose setting sleeve relative to the drive sleeve is prevented by a mechanical engagement of the drive sleeve and the dose setting sleeve in the unprimed state of the assembly, and

wherein the mechanical engagement of the drive sleeve and the dose setting sleeve is released during the priming operation.

2. Assembly according to the preceding aspect,

wherein, during the priming operation, a priming dose is dispensed from the device, and

wherein the priming operation has to be performed before a dose can be set for the first time.

3. Assembly according to one of the preceding aspects,

wherein the assembly is configured such that, during the priming operation, the drive sleeve is moved relative to the dose setting sleeve purely linear in the distal direction.

4. Assembly according to one of the preceding aspects,

wherein the drive sleeve comprises an engagement feature,

wherein the dose setting sleeve comprises a priming track, wherein, in the unprimed state of the assembly, the drive sleeve and dose setting sleeve are mechanically engaged by the engagement feature being arranged in the priming track.

5. Assembly according to the preceding aspect,

wherein the priming track is configured to guide a movement of the drive sleeve relative to the dose setting sleeve during the priming operation.

6. Assembly according to aspect 4 or 5,

wherein the dose setting sleeve comprises one or more dosing tracks which are parallel to the priming track,

wherein the assembly is configured such that the engagement feature of the drive sleeve engages one of the dosing tracks for setting a dose of the medication.

7. Assembly according to the preceding aspect,

wherein the one or more dosing tracks are longer than the priming track. In an alternative embodiment the priming track may have the same length as one of the dosing tracks. The device may be configured such that the engagement feature cannot re-enter the priming track after it has been disengaged from the priming track. For this purpose, the end of the priming track may be formed with a “one-way” feature. For example, the engagement feature may comprise a flexible protrusions and a bump or a detent may be formed as the one-way feature at the distal end of the priming track. The one-way feature may be arranged and designed to prevent the engagement feature from re-entering the priming track.

8. Assembly according to one of aspects 6 or 7,

wherein the length of the priming track corresponds to the distance by which the piston rod is displaced during the priming operation, and

wherein the length of a dosing track corresponds to the distance by which the piston rod is displaced when a dose is dispensed from the device, wherein the engagement feature has been engaged with said dosing track in a dose setting operation performed before dispensing the dose.

9. Assembly according to one of the aspects 4 to 8,

wherein the assembly comprises a longitudinal axis, and

wherein the priming track is parallel to the longitudinal axis.

10. Assembly according to one of the preceding aspects,

wherein the dose setting sleeve is enabled to rotate relative to the drive sleeve in the primed state of the assembly.

11. Assembly for a medication delivery device,

wherein the assembly has an unprimed state and a primed state, wherein the assembly is configured to be transferred from its unprimed state to its primed state by performing a priming operation,

wherein the assembly comprises a dose setting sleeve, a drive sleeve, a piston rod and a body,

wherein the dose setting sleeve has to be rotated relative to the drive sleeve for setting a dose of the medication,

wherein the drive sleeve is configured to move the piston rod in a distal direction relative to the body for dispensing the dose,

wherein the assembly is configured such that, when the dose setting sleeve is rotated relative to the drive sleeve for the first time, the priming operation is performed.

12. Assembly according to the preceding aspect,

wherein the dose setting sleeve comprises a priming track and one or more dosing tracks,

wherein the drive sleeve comprises an engagement feature configured to engage with one of the priming track and the one or more dosing tracks,

wherein the assembly is configured such a dose setting operation comprises a first step wherein the engagement feature is aligned with one of the dosing tracks by rotating the dose setting sleeve relative to the drive sleeve and a second step wherein the engagement feature is moved along the dosing track to which it has been aligned in the first step,

wherein the assembly is configured such that, when a dose setting operation is performed for the first time, the priming operation is performed during the first step of the dose setting operation.

13. Assembly according to the preceding aspect,

wherein the priming track is helical.

14. Assembly according to one of the aspects 12 or 13,

wherein the engagement feature is arranged in the priming track in the unprimed state.

15. Assembly according to one of the aspects 12 to 14,

wherein the assembly is configured such that the engagement feature is disengaged from the priming track when the dose setting sleeve is rotated relative to the drive sleeve for the first time.

16. Medication delivery device comprising an assembly according to one of the preceding aspects wherein the medication delivery device is a variable-dose, single-use device.

17. Medication delivery device according to the preceding aspect,

wherein either the medication delivery device comprises a cartridge comprising a medication which is dispensed in a dose delivery operation by the assembly or the medication delivery device is a syringe comprising a medication which is dispensed in a dose delivery operation by the assembly.

In the following text, another set of advantageous aspects is described. The aspects are numbered to facilitate referencing features of one aspect in other aspects. Features from the aspects are not only relevant in connection with the specific aspects they relate to but are also of relevance on their own.

The aspects discussed in the following refer to embodiments wherein the assembly is configured to prevent an accidental lock-out of the assembly before a dose setting operation has been performed. The lock-out may correspond to a configuration wherein no further operation of the assembly is possible, e.g., because some of the components of the assembly can no longer be moved relative to each other. The assembly may be designed to be locked-out after delivering a dose. However, it should be ensured that an accidental lockout before delivering a dose is prevented. Thus, the aspects discussed in the following may solve the object to improve the usability of the assembly by providing a simple mechanism that prevents an accidental lock-out. The mechanism may require only a minimal number of components.

1. Assembly for a medication delivery device,

wherein the assembly comprises a piston rod and a body,

wherein the assembly comprises a drive sleeve configured to move the piston rod in the distal direction for dispensing a dose,

wherein the assembly comprises a deflectable feature,

wherein the assembly comprises a first stop face,

wherein the assembly is configured to be transferred into a locked-out state by the deflectable feature overriding the first stop face, wherein in the locked-out state, any movement of the drive sleeve relative to the body is prevented, and

wherein the assembly is configured such that, before setting a dose for the first time, the piston rod is arranged such that the piston rod prevents a deflection of the deflectable feature, thereby preventing the deflectable feature from overriding the first stop face.

2. Assembly according to the preceding aspect,

wherein the deflectable feature is arranged on the drive sleeve.

3. Assembly according to one of the preceding aspects,

wherein the piston rod comprises a section having a maximum radial extension,

wherein the section having the maximum radial extension is aligned with the deflectable feature before a dose is set for the first time, thereby preventing the deflection of the deflectable feature.

4. Assembly according to the preceding aspect,

wherein the assembly is configured such that the drive sleeve is moved in the proximal direction relative to the piston rod for setting a dose, thereby moving the section having the maximum radial extension away from the deflectable feature and, thus, allowing a deflection of the deflectable feature.

5. Assembly according to one of the preceding aspects,

wherein the assembly comprises a second stop face,

wherein the assembly is configured such that the deflectable feature overrides the first stop face when dispensing a previously set dose, and wherein the assembly is configured such that the deflectable feature abuts the second stop face after overriding the first stop face.

6. Assembly according to the preceding aspect,

wherein the second stop face is adapted and arranged to prevent a movement of the drive sleeve in the proximal direction relative to the body.

7. Assembly according to one of the aspects 7 or 8,

wherein the assembly is configured such that no dose can be set when the drive sleeve abuts the second stop face.

8. Assembly according to one of the preceding aspects,

wherein the assembly comprises a dose setting sleeve configured to be rotated relative to the body for setting a dose,

wherein the dose setting sleeve comprises the first stop face.

9. Assembly according to the preceding aspect,

wherein the assembly has an unprimed state and a primed state,

wherein the assembly is configured to be transferred from its unprimed state to its primed state by performing a priming operation,

wherein the assembly is configured such that the deflectable feature is brought into abutment with the first stop face during the priming operation.

10. Assembly according to the preceding aspect,

wherein the assembly is configured such that, during the priming operation, the piston rod is displaced in the distal direction by a distance which is identical to the distance of the deflectable feature to the first stop face in the unprimed state of the assembly.

11. Assembly according to one of the aspects 8 or 9,

wherein the assembly is configured such that the priming operation has to be performed before setting a dose for the first time.

12. Assembly according to one of the preceding aspects,

wherein the assembly is configured such that a distal movement of the drive sleeve relative to the body is prevented when the deflectable feature abuts the first stop face and the piston rod prevents a deflection of the deflectable feature.

13. Assembly according to the preceding aspect,

wherein the first stop face is shaped to enable the deflectable feature to override the first stop face, and

wherein the deflectable feature is adapted and arranged such that it is enabled to override the first stop face when the deflectable feature deflects inwardly.

14. Medication delivery device comprising an assembly according to one of the preceding aspects wherein the medication delivery device is a variable-dose, single-use device.

15. Medication delivery device according to the preceding aspect,

wherein either the medication delivery device comprises a cartridge comprising a medication which is dispensed in a dose delivery operation by the assembly or the medication delivery device is a syringe comprising a medication which is dispensed in a dose delivery operation by the assembly.

Features which are described herein above and below in conjunction with different aspects or embodiments, may also apply for other aspects and embodiments. Further aspects, features and advantages of the present invention will be apparent from the following description of preferred embodiments with reference to the accompanying drawings.

