Injection Device and Container for an Injection Device

Abstract

In one aspect the present disclosure relates to an injection device. The injection device includes a housing configured to receive a container; a drive mechanism having a plunger configured to urge against a bung in the container in a distal direction to expel the dose of the medicament from the container, wherein the plunger is configured to releasably connect to the bung to form a plunger bung assembly; a container moving mechanism configured to move the container relative to the housing between a proximal replacement position and a distal injection position; at least one retainer configured to prevent a proximally directed movement of the container relative to the housing. The drive mechanism is configured to retract the plunger and the plunger bung assembly along the proximal direction relative to the tubular barrel of the container.

Claims

1-15. (canceled)

16. An injection device for injecting of a dose of a liquid medicament, the injection device comprising: a housing configured to receive a container, wherein the container comprising a tubular barrel filled with the liquid medicament is sealed by a bung in a proximal direction, and wherein the bung is slidably arranged inside the tubular barrel; a drive mechanism having a plunger configured to urge against the bung in a distal direction to expel the dose of the liquid medicament from the container, wherein the plunger is configured to releasably connect to the bung to form a plunger bung assembly; a container moving mechanism configured to move the container relative to the housing between a proximal replacement position and a distal injection position; and at least one retainer configured to prevent a proximally-directed movement of the container relative to the housing, wherein the drive mechanism is configured to retract the plunger and the plunger bung assembly along the proximal direction relative to the tubular barrel of the container.

17. The injection device according to claim 16, wherein the at least one retainer comprises a distal retainer configured to retain the container in the distal injection position.

18. The injection device according to claim 17, wherein the distal retainer is de-activatable to allow the proximally-directed movement of the container relative to the housing towards the proximal replacement position.

19. The injection device according to claim 16, wherein the at least one retainer comprises a proximal retainer configured to retain the container in the proximal replacement position.

20. The injection device according to claim 16, wherein the plunger comprises a connector to releasably connect with a counterpart connector of the bung.

21. The injection device according to claim 16, wherein the container moving mechanism is configured to slidably displace the container between the proximal replacement position and the distal injection position, and wherein the container moving mechanism comprises a drive to induce or to control a motion of the container relative to the housing.

22. The injection device according to claim 21, wherein the drive is provided by the plunger connected to the bung and movable relative to the housing.

23. The injection device according to claim 16, further comprising the container arranged inside the housing.

24. The injection device according to claim 23, wherein the container comprises a needle holder configured to hold an injection needle, and wherein the needle holder is retractable inside the tubular barrel.

25. The injection device according to claim 24, wherein the bung comprises a connector facing towards the needle holder, wherein at least one of the needle holder or the injection needle comprises a counterpart connector facing towards the bung, and wherein the connector and the counterpart connector are configured to form a mechanical interconnection between the bung and the needle holder.

26. The injection device according to claim 24, wherein the needle holder comprises a seal in fluid tight engagement with the tubular barrel of the container.

27. A container for a liquid medicament, the container comprising: a tubular barrel; a bung sealing a proximal end of the tubular barrel, wherein the bung comprises a connector facing towards a distal end of the tubular barrel; and a needle holder configured to hold an injection needle and retractable inside the tubular barrel, wherein the needle holder comprises a seal in fluid tight engagement with the tubular barrel, wherein at least one of the needle holder or the injection needle comprises a counterpart connector configured to engage with the connector to form a mechanical interconnection with the bung.

28. The container according to claim 27, wherein the needle holder comprises a socket configured to protrude axially through an orifice at a distal end of the tubular barrel, and wherein the socket comprises an outer thread to engage with an inner thread of a cup-shaped needle assembly.

29. The container according to claim 28, wherein the needle holder comprises a radially widening shoulder portion axially adjacent to the socket.

30. The container according to claim 27, further comprising a rotation lock configured to prevent a rotation between the needle holder and the tubular barrel, wherein the rotation lock comprises at least one radial protrusion configured to engage with at least one complementary-shaped radial recess.

31. The container according to claim 30, wherein the at least one radial protrusion is located on one of the needle holder and the tubular barrel, and the at least one complementary-shaped radial recess is located on the other of the needle holder and the tubular barrel.

32. The container according to claim 30, wherein the at least one radial protrusion faces inwardly from an inwardly facing circumference of a flange confining an orifice of the tubular barrel, and the at least one complementary-shaped radial recess is located on an outer surface of the needle holder.

33. The container according to claim 30, wherein the at least one radial protrusion and the at least one complementary-shaped radial recess extend in a longitudinal direction.

34. A method of exchanging a medicament container in an injection device, the method comprising: retracting a needle holder into a barrel of the medicament container; moving the medicament container relative to a housing of the injection device from a distal injection position into or towards a proximal replacement position; providing access to the medicament container after the needle holder and/or after the medicament container has been moved to the proximal replacement position; and removing the medicament container from the housing and inserting another medicament container into the housing.

35. The method according to claim 34, wherein moving the medicament container relative to the housing of the injection device from the distal injection position into or towards the proximal replacement position comprises moving the medicament container relative to the housing towards and into the proximal replacement position while the needle holder remains stationary relative to the barrel of the medicament container.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0133] In the following, numerous examples of the medicament container and of an injection device will be described in greater detail by making reference to the drawings, in which:

[0134] FIG. 1 is a schematic side view of an injection device equipped with a container, wherein the container is in the proximal replacement position,

[0135] FIG. 2 shows the injection device according to FIG. 1 with the medicament container in the distal injection position,

[0136] FIG. 3 shows the device according to FIGS. 1 and 2 after emptying of the container,

[0137] FIG. 4 shows the injection device according to FIGS. 1-3 with the container in distal injection position and after retracting the bung and the needle holder of the container into the barrel of the container, and

[0138] FIG. 5 shows the injection device of FIG. 4 after returning of the container back into the proximal replacement position for exchanging the container by another container,

[0139] FIG. 6 is a schematic illustration of one example of a container in the proximal replacement position,

[0140] FIG. 7 shows the container of FIG. 6 in the distal injection position before dispensing of the medicament,

[0141] FIG. 8 shows the container of FIG. 7 after expelling of the medicament with the injection needle retracted into the barrel of the container and with the container returned in the proximal replacement position and

[0142] FIG. 9 shows the configuration of the container of FIG. 8 with the plunger disconnected from the bung of the container,

[0143] FIG. 10 is a flowchart of a method of exchanging a medicament container,

[0144] FIG. 11a is an enlarged side view of the bung according to FIGS. 6-9,

[0145] FIG. 11b is a front view of the distal end face of the bung,

[0146] FIG. 12 is an enlarged view of a needle holder used with a container as illustrated in FIGS. 13-16,

[0147] FIG. 13 shows another example of a container located in a proximal replacement position,

[0148] FIG. 14 shows the container of FIG. 13 in the distal injection position,

[0149] FIG. 15 shows the container of FIG. 14 after connecting the bung with the needle holder and after retracting the bung and the needle holder into the barrel of the container,

[0150] FIG. 16 shows the container in the proximal replacement position before the plunger is disconnected from the bung, and

[0151] FIG. 17 is a cross-section through the barrel and the needle holder according to A-A of FIG. 14.

DETAILED DESCRIPTION

[0152] In the sequence of FIGS. 1-5 an injection device 10 is schematically illustrated. The injection device 10 is configured or implemented as an auto-injector that is capable to pierce the skin of a patient with an injection needle and to expel a predefined amount of a medicament, i.e. a dose of the medicament, into the pierced tissue. The injection device may comprise a handheld pen-type injector. When implemented as an auto-injector the injection device 10 is configured to advance the injection needle 41 relative to a housing 11 in the distal direction 2 so as to puncture the skin of the patient.

[0153] After completion of the injection procedure the injection device 10 is configured to retract and to withdraw the injection needle from the skin of the patient and to retract the needle inside the housing 11 of the injection device 10. The injection device 10 is configured to receive a container 30 having a tubular-shaped barrel 31 filled with a liquid medicament 5. The housing 11 comprises a proximal end and an oppositely located distal end 2. In FIG. 1, the proximal direction 3 and the distal direction 2 are indicated by respective arrows. The distal end 28 of the injection device 10 is the dispensing end facing towards the pierceable skin of the patient. The medicament container 30 comprises a piston or bung 32 sealing the tubular barrel 31 towards the proximal direction 3. The bung 32 is slidably arranged inside the barrel 31.

[0154] In an initial configuration as illustrated in FIG. 1 the bung 32 is located at or near a proximal end 33 of the barrel 31. At or near the distal end 35 of the barrel 31 there is provided a needle holder 40. The needle holder 40 is equipped with an injection needle 41. Optionally, the needle holder 40 comprises a seal 42 in fluid tight engagement with the inside facing sidewall of the barrel 31. The barrel 31 may be open ended at its distal end 35. It may comprise a radially inwardly extending flange 39 as illustrated in the more detailed illustration of FIGS. 6-9. The distal end of the injection needle 41 may protrude from the distal end 35 of the barrel 31 in the initial configuration as illustrated in FIG. 1. The needle holder 40 comprises a counterpart connector 44 complementary shaped to a connector 36 of the bung 32. The connector 36 of the bung 32 faces in distal direction 2, hence towards the needle holder 40. The counterpart connector 44 of the needle holder 40 faces towards the proximal direction 3, hence towards the bung 32.

[0155] The injection device 10 further comprises a drive mechanism 12 having at least a plunger 14 being moveable along the axial direction, hence towards the distal direction 2 and towards the proximal direction 3 relative to the housing 11. The drive mechanism 12 may be all mechanically implemented. It may be driven by a mechanical energy reservoir, such as a spring. With other examples the drive mechanism 12 may comprise an electromechanical drive and may be electrically controlled, e.g. by a control 7 of the injection device 10. Moreover, the injection device comprises a dose setting member 8 and a trigger 9. By means of the dose setting member 8 at least the size of a dose or other dosing parameters, such as the injection velocity may be modified or set. By means of the trigger a dose dispensing action can be initiated and/or controlled or prematurely interrupted if required.

[0156] The injection device further comprises a container moving mechanism 20 by way of which the container 30 can be moved relative to the housing 11 between a proximal replacement position P as illustrated in FIGS. 1 and 5 and a distal injection position D as illustrated in FIGS. 2-4. The container moving mechanism 20 may comprise a separate drive 21 configured to displace the container 30 relative to the housing 11. In addition to that or alternative to the drive 21 also the plunger 14 and the drive mechanism 12 may provide or form a driver 22 configured for moving the container 30 between the distal injection position D and the proximal replacement position P.

[0157] The plunger 14 comprises a connector 24 located at a distal end of the plunger 14 and hence facing towards a proximal end of the bung 32. The bung 32 comprises a counter connector 34 complementary or correspondingly-shaped to the connector 24 of the plunger 14. The counter connector 34 is located at a proximal side of the bung 32 and faces towards the proximal direction 3. The connector 24 and the complementary shaped counter connector 34 are configured to releasably connect to form a plunger bung assembly 15 as illustrated in FIG. 2. The mutually corresponding connector 24 and counter connector 34 may be configured to form a snap fit, a positive fit or a positive locking of the bung 32 and the plunger 14.

[0158] The mutual interconnection between the plunger 14 and the bung 32 is tension stable and exhibits a tensile strength that is larger than a friction force required for moving the bung 32 relative to the barrel 31. The interconnection between the plunger 14 and the bung 32 may be of load limiting type. If for instance a proximally directed movement of the bung 32 is impeded or blocked and if the plunger 14 exerts a tensile stress to the bung 32 exceeding the predefined maximum load the interconnection between the plunger 14 and the bung 32 abrogates. The container moving mechanism 20 may comprise a sliding mechanism to slidably support the medicament container 30 inside the housing 11.

[0159] In FIG. 1 an initial and undeployed configuration of the injection device 10 is schematically illustrated. The container 30 filled with the injectable medicament 5 has been inserted into the housing 11 and a protective cap 38 as illustrated in FIG. 6 has been removed prior to a first use of the injection device 10. After setting an initial dose and after an eventual priming procedure the medicament container 30 is displaced in distal direction 2 until it arrives at the distal injection position D. In the distal injection position D the distal end 35 of the container 30 may abut with an abutment section, e.g. in form of a flange 27 at or near a distal end 28 of the housing 11. When arriving at the distal injection position the injection needle 41 protrudes from the distal end 28 of the housing 11. Presuming that the distal end 28 of the housing 11 is in contact with an injection site of a patient the respective tissue, hence the skin 4 of the patient will be pierced as indicated in FIG. 7.

[0160] The distally directed motion and displacement of the medicament container 30 into the distal injection position D is governed or conducted by at least one of the drive mechanism 12 and a separate drive 21 of the container moving mechanism 20. The drive 21 is only optional. Generally, the drive mechanism 12 and the plunger 14 may be operable to displace the container 30 into the distal injection position. Here, the container moving mechanism 20 is constituted by the drive mechanism 12 and the plunger 14 connected to the bung 32. The plunger 14 can be driven in distal direction 2 until it gets in abutment with the bung 32. The friction force between the bung 32 and the inside surface of the tubular barrel 31 is typically larger than a force required for moving the container 30 from the proximal replacement position P towards and into the distal injection position D. The friction force between the bung 32 and the barrel 31 may be even larger than a force required for piercing the skin 4 by the needle 41.

[0161] In FIG. 3 a configuration is illustrated wherein the entirety of the medicament 5 has been dispensed through the injection needle 41. Generally, the content of the container 30 may be sufficient to conduct several injection procedures.

[0162] If a last dose of the medicament 5 has been dispensed the bung 32 reaches a distal most position inside the barrel 31 as illustrated in FIG. 3. There, the distally facing connector 36 of the bung 32 mechanically engages with the proximally facing counter connector 44 of the needle holder 40. In this way, a tension stable connection between the bung 32 and the needle holder 40 is established. Since the bung 32 is connected to the plunger 14 a movement of the plunger 14 towards the proximal direction 3 induced by the drive mechanism 12 leads to a respective displacement of the bung 32 and of the needle holder 40 provided that the medicament container 30 is secured inside the housing 11 against a proximally directed displacement or movement.

[0163] In order to prevent a premature proximally directed movement of the container 30 from the distal injection position D towards the proximal replacement position P the injection device 10 comprises a distal retainer 16. The distal retainer 16 is configured to get in axial abutment with at least a portion, e.g. with a proximally facing flange or with an end face of the barrel 31 of the medicament container 30. As illustrated in FIGS. 2-4 the distal retainer 16 is located at a longitudinal position of the housing 11 that coincides with the proximal end face of the barrel 31. In this way and when arriving at the distal injection position D the barrel 31 is axially confined between the flange 27 at the distal end of the housing 28 and the distal retainer 16.

[0164] The distal retainer 16 is at least temporally deactivatable to allow and to support a proximally directed movement or retraction of the container 30 relative to the housing 11 towards the proximal replacement position P. After termination of a last injection from the container 30 as indicated in FIG. 3, the distal retainer 16 is activated so as to prevent a proximally directed movement of the container 30 relative to the housing 11. A proximally directed movement of the plunger 14 connected to the bung 32 and connected to the needle holder 40 then leads to a retraction of the needle holder 40 and of the injection needle 41 into the interior of the barrel 31 until the distal end of the injection needle 41 is located proximal from the distal end 35 of the barrel 31. This situation is indicated in FIG. 4.

[0165] Thereafter, the distal retainer 16 is deactivated or released so as to allow and to support a proximally directed movement of the container 30 towards and into the proximal replacement position P. The housing 11 may comprise a closure 25, e.g. equipped with a lid providing access to the container 30 only when the container 30 is in the proximal replacement position P. The closure 25 may be limited in size and may be only slightly larger than the barrel 31 of the cartridge. In this way and as long as the needle 41 protrudes from the distal end 35 of the barrel 31 the container 30 may be hindered from removal of the housing 11.

[0166] The sequence of FIGS. 6-9 shows one example of the container 30 in more detail as it is positioned inside the housing 11 of the injection device 10. In the initial configuration as illustrated in FIG. 6 the distal end 35 of the container 30 is provided with a protective cap 38. In The sequence of FIGS. 6-9 there are always provided vertical lines 28, 4. The line 28 represents the distal end of the housing 11 of the injection device 10 and the vertical line 4 represents the pierceable skin of a patient. In the initial configuration as illustrated in FIG. 6 a portion of the protective cap 38 protrudes from the distal end 28 of the housing. Typically, it protrudes through the orifice 26 as illustrated in FIG. 1. A user may grasp the protruding portion of the protective cap 38 and withdraw the protective cap thus exposing the injection needle 41. In the proximal replacement position P the distal end of the injection needle 41 is located entirely inside the housing 11. It does not yet protrude from the housing.

[0167] With the example of FIGS. 6-9 the needle holder 40 comprises a seal 42 in sealing and fluid tight engagement with an inside of the barrel 31. As illustrated in FIG. 8 the barrel 31 comprises a radially inwardly extending flange 39 at its distal end 35. The annular-shaped and radially inwardly extending flange 39 encloses a distal orifice 37 at the distal end face of the barrel 31. Through this orifice 37 there extends at least a portion of the needle holder 40. The needle holder 40 comprises a stepped down distally protruding socket section 46 protruding through the orifice 37 of the barrel 31 when in the initial configuration as illustrated in FIGS. 6 and 7. The injection needle 41 extends entirely through the needle holder 40. The seal 42 comprises a radially widening shoulder proximally adjacent to the stepped down socket section 46. The circumference or radial extension of the shoulder portion 46 is larger than the cross-section or inner diameter of the orifice 37. Hence, a distally facing abutment side of the shoulder portion 43 is in axial abutment with a proximally facing side of the flange 39.

[0168] The hollow and cannula type injection needle 41 comprises a distal tipped end and further comprises a counterpart connector 44 at its proximal end. The counterpart connector 44 may comprise a bulged shape to interconnect with the connector 36 located at the distal side of the bung 32. As illustrated in FIGS. 11a and 11b the connector 36 comprises a receptacle 34b configured to receive the bulge of the injection needle 41. As illustrated in FIG. 11b the receptacle 34b is formed in a tapered radial central portion of the bung 32. The receptacle 34b is intersected by two perpendicularly oriented slits thus forming four lobes or wings 36a, 36b, 36c and 36d being resiliently deformable so as to releasably engage with the bulge of the counterpart connector 44 of the injection needle 41.

[0169] As illustrated further in FIG. 11a the bung 32 comprises a counterpart connector 34 at a proximal end and facing towards the plunger 14. The counterpart connector 34 is configured to engage with a T-shaped connector 24 of the plunger 14. For this the connector 24 comprises a radially widened head 24a at a distal end connected with a proximal portion of the plunger 14 via a neck portion 24b. The neck portion 24b is configured to extend through a through opening formed by and extending between oppositely located radially inwardly extending flange portions 34a at the proximal end of the bung 32. The bung 32 is made of a resilient material and the flange portion 34 may be configured to widen radially as the head 24a of the plunger is urged into the receptacle 34b of the counterpart connector.

[0170] As illustrated in FIGS. 6-9 the connector 24 and the counterpart connector 34 are configured to form a snap fit connection that establishes automatically as the plunger 14 is driven in distal direction 2 against the bung 32. As the bung 32 has reached a distal end position, which is currently not illustrated and as the connector 36 mechanically connects to the counterpart connector 44 the bung 32 is in a tension stable connection with the injection needle 41 and the needle holder 40. Then, the needle holder 40 together with the bung 32 can be retracted into the barrel 31 and the container 30 can be retracted from the distal injection position D to and into the proximal replacement position P as illustrated in FIGS. 8 and 9.

[0171] Once arrived at the proximal replacement position P as illustrated in FIG. 8 the proximal end 33 of the container 30 is in axial abutment with a proximal retainer 18. The proximal retainer 18 may be connected to or may be integrally formed with the housing 11. The proximal retainer 11 comprises a through opening 19 that is large enough for the plunger 14 to pass through. The through opening 19 is in fact smaller than the outer dimensions of the proximal end 33 of the barrel 31 as well as the outer dimensions of the bung 32.

[0172] When arriving in the proximal replacement position P as illustrated in FIG. 8 the proximal end 33 of the barrel 31 and a proximal end of the bung 32 are in axially abutment with the proximal retainer 18. In this way, any further proximally directed displacement of the container 31 and of its bung 32 is impeded and blocked by the proximal retainer 18. Since the mutual interconnection between the plunger 14 and the bung 32 is of load limiting type the interconnection between the connector 24 and the counterpart connector 34 can be abrogated as the plunger 14 is moved further in proximal direction so that a mechanical tension across the interface of plunger 14 and bung 32 exceeds the predefined maximum load.

[0173] After applying such excessive force to the plunger 14 in proximal direction 3 the plunger 14 disconnects from the bung 32 and hence from the container 30. The container 30 can then be removed or replaced by another container.

[0174] In FIG. 10 various steps of conducting a method of exchanging a medicament container are illustrated. The method starts after completion of an injection procedure. In a first step 100 a needle holder 40 is retracted into a barrel 31 of a medicament container 30. In a further step 102 the medicament container 30 is moved relative to a housing 11 of the injection device 10 from a distal injection position D into or towards a proximal replacement position P.

[0175] The sequence of the steps 100 and 102 may also be exchanged or the steps 100 and 102 may be conducted at a certain temporal overlap. The steps 100 and 102 may even be conducted simultaneously. With either step 100 or 102 the injection needle 41 still penetrating the skin 4 of a patient after completion of the injection procedure is withdrawn from the skin 4 of the patient.

[0176] For the method it is generally sufficient when only step 100 is performed so that the needle holder 40 is retracted into the barrel 31 of the medicament container 30. Step 102 may be only optional. After the needle holder 40 has been retracted into the barrel 31 in step 103 there is provided access to the medicament container 30 which is still located inside the housing 11 of the injection device 10. In a subsequent step 104 the medicament container 30 is removed from the housing 11 and in the further step 105 another medicament container 30 is inserted into the housing 11 of the injection device 10. Thereafter, subsequent dose setting and injection procedures may take place with the new medicament container.

[0177] In FIG. 12 a further example of a needle holder 140 is illustrated. The needle holder 140 is also insertable into the interior of a barrel 131 of a medicament container 130 as illustrated in more detail in FIGS. 13-16. The illustration of FIGS. 13-16 is in close analogy to the illustration of FIGS. 6-9. Here, identical or similar components are indicated with identical or similar reference numbers as used before in connection with FIGS. 6-9. Similar components are indicated with reference numbers increased by 100.

[0178] The needle holder 140 comprises a step down socket portion 146 at its distal end protruding through an orifice 137 at a distal end 135 of a barrel 131 of the medicament container 130. The orifice 137 and the distal end 135 are laterally confined by a radially inwardly extending flange 139 protruding radially inwardly from a sidewall of the barrel 131. In the initial configuration as illustrated in FIG. 13 the socket 146 protrudes distally from the distal end of the barrel 135. The socket 146 is a threaded socket comprising an outer thread 148. The outer thread 148 is configured to threadedly engage with an inner thread 154 of a cupped receptacle 152 of a needle assembly 150 illustrated in FIG. 14. The step of attaching of the needle assembly 150 to the socket 146 of the needle holder 140 is not illustrated.

[0179] In FIG. 14 the needle assembly 150 is illustrated as the injection needle 141 already pierces the skin 4 of the patient. The needle assembly 150 comprising the cupped receptacle 152 intersected by the double-tipped injection needle 141 may be readily assembled on the threaded socket 148 even before the protective cap 38 is taken away. The protruding socket 146 comprises a pierceable closure 145 that hermetically separates a hollow channel section 147 of the needle holder 140 from an outer surface of the needle holder 140. The needle holder 140 is made of an elastomeric material, such as natural or synthetic rubber. The pierceable closure 145 forms a kind of a pierceable septum located in a radial center of the threaded socket 146.

[0180] The needle holder 140 comprises a radially widened shoulder section 143 proximally adjacent to the threaded socket 146. The needle holder 140 further comprises an axial mid-section 149 located axially between the shoulder portion 143 and the threaded socket 146. The cross-section or diameter of the mid-section 149 matches with the inner diameter of the orifice 137 of the barrel 131. The outer circumference of the seal 142 and hence of the shoulder section 143 matches with the inner circumference or inner cross-section of the sidewall of the barrel 131 and the threaded socket 146 is reduced in diameter compared to the inner cross-section of the orifice 137. The diameter reduction of the threaded socket 146 compared to the mid-section 149 matches with the radial thickness of the threaded engagement of the threaded socket 146 with the cupped receptacle 152.

[0181] In this way, the needle assembly 150 in threaded engagement with the threaded socket 146 can be retracted together with the needle holder 140 in proximal direction 3 into the barrel 131 of the container 130.

[0182] The channel section 147 comprises a snap feature thus forming a counterpart connector 144 to engage with a connector 136 of the bung 132. The bung 132 comprises a counterpart connector 134 that is substantially identical to the counterpart connector 34 as illustrated and described in connection with FIGS. 6-9. The connector 136 comprises a snap feature 136a to engage with the snap feature 144a of the counterpart connector 144. Here, the snap feature 136a is a male snap feature and the snap feature 144a is a female snap feature extending into or spatially overlapping with the channel section 147 through which the medicament 5 is to be expelled once the double-tipped injection needle 141 has pierced the pierceable closure 145 at the distal end face of the needle holder 140.

[0183] The mutually corresponding snap features 136a, 144a comprise beveled structures facing in distal direction 2 so as to facilitate establishing of a mechanical connection between the bung 132 and the needle holder 140. A withdrawal force for disconnecting the bung 132 and the needle holder 140 is therefore substantially larger than a force required for establishing the snap fit engagement of the connector 136 and the counterpart connector 144.

[0184] In FIG. 17 a cross-section A-A according to FIG. 14 is illustrated. FIG. 17 is illustrative of a rotation lock 160 configured to prevent a rotation of the needle holder 140 relative to the barrel 131 or relative to the container 130 as long as the needle holder 140 is located at the distal end 135 of the container 130. The rotation lock 160 comprises a radial protrusion 161 and a complementary shaped radial recess 162.

[0185] The radial protrusion 161 is located on one of the barrel 131 and the needle holder 140, wherein the complementary shaped radial recess 162 is located on the other one of the barrel 131 and the needle holder 140. In the illustration of FIG. 17 the protrusion 161 is located on the radially inwardly extending flange 139 at the distal end 135 of the barrel 131. The protrusion 161 protrudes radially inwardly into the orifice 137. The complementary shaped recess 162 is provided on an outer surface of the midsection 149 of the needle holder 140. In the initial configuration and hence prior to a retraction of the needle holder 140 into the interior of the container 130 or barrel 131 the midsection 149 axially or longitudinally intersects the orifice 137 radially confined by the flange 139.

[0186] As long as the at least one protrusion 161 and the at least one recess 162 are in mechanical engagement the needle holder 140 is rotationally fixed to the barrel 131. A user may then attach a needle assembly 150 to the threaded socket 146 protruding from the distal end 135 of the barrel 131. The rotational interlock between the barrel 131 and the needle holder 140 is of particular benefit to enable a screwing connection between the needle assembly 150 and the needle holder 140.

[0187] As illustrated in FIG. 17 there is provided a pair of substantially equally shaped rotation locks 160 circumferentially distributed around the outer circumference of the needle holder 140. With numerous rotational locks 160 a holding torque between the barrel 131 and the needle holder 140 can be equally distributed among the number of available rotational locks. Mechanical point loads to each rotation lock 160 can be thus reduced.

LIST OF REFERENCE NUMBERS

[0188] 2 distal direction [0189] 3 proximal direction [0190] 4 skin [0191] 5 medicament [0192] 7 control [0193] 8 dose setting member [0194] 9 trigger [0195] 10 injection device [0196] 11 housing [0197] 12 drive mechanism [0198] 14 plunger [0199] 15 plunger bung assembly [0200] 16 retainer [0201] 18 retainer [0202] 19 through opening [0203] 20 container moving mechanism [0204] 21 drive [0205] 22 drive [0206] 24 connector [0207] 24a head portion [0208] 24b neck portion [0209] 25 closure [0210] 26 orifice [0211] 27 flange [0212] 28 distal end [0213] 30 container [0214] 31 barrel [0215] 32 bung [0216] 33 proximal end [0217] 34 counterpart connector [0218] 34a flange portion [0219] 34b receptacle [0220] 35 distal end [0221] 36 connector [0222] 36a, b, c, d wings [0223] 37 orifice [0224] 38 cap [0225] 39 flange [0226] 40 needle holder [0227] 41 injection needle [0228] 42 seal [0229] 43 shoulder portion [0230] 44 counterpart connector [0231] 46 socket [0232] 130 container [0233] 131 barrel [0234] 132 bung [0235] 133 proximal end [0236] 134 counterpart connector [0237] 135 distal end [0238] 136 connector [0239] 136a snap feature [0240] 137 orifice [0241] 139 flange [0242] 140 needle holder [0243] 141 injection needle [0244] 142 seal [0245] 143 shoulder portion [0246] 144 counterpart connector [0247] 145 pierceable closure [0248] 146 threaded socket [0249] 147 channel section [0250] 148 outer thread [0251] 149 mid-section [0252] 150 needle assembly [0253] 152 receptacle [0254] 154 inner thread [0255] 160 rotational lock [0256] 161 protrusion [0257] 162 recess