A medicment delivey system and a drive sub-assembly

Abstract

The present invention relates to an advantageous reusable drive sub-assembly for a medicament delivery system. The reusable drive sub-assembly is configured to be removably rotationally attachable to a syringe sub-assembly between an attached configuration and a detached configuration. The reusable drive sub-assembly comprises a housing, a piston rod configured to be moved between a proximal position and a distal position, a piston rod biasing member configured to bias the piston rod into the distal position, and a clutch mechanism located in the housing and releasably rotationally lockable to the piston rod. The clutch mechanism is engageable by a mating portion of a removable syringe sub-assembly when a removable syringe sub-assembly is rotationally attached to the reusable drive sub-assembly. The clutch mechanism is configured to move the piston rod from its distal position to its proximal position when a removable syringe sub-assembly and the reusable drive sub-assembly are moved from their attached configuration to their detached configuration. The present invention also relates to a medicament delivery system and a method of recharging a reusable drive sub-assembly.

Description

[0001] A MEDICMENT DELIVEY SYSTEM AND A DRIVE SUB-ASSEMBLY

[0002] FIELD OF INVENTION

[0003] The present invention relates to a medicament delivery system and a drive sub-assembly and a method of recharging a drive sub-assembly of the medicament delivery system for reuse.

[0004] BACKGROUND

[0005] Medicament delivery devices, such as auto-injectors, are known in the art for dispensing a medicament to an injection site of a patient. Such medicament delivery devices typically comprise needle in fluid communication with a syringe and a piston rod that is moveable to dispense the medicament within the syringe through the needle into the injection site.

[0006] In such medicament delivery devices the piston rod is biased towards the injection site to dispense the medicament. Once the medicament has been dispensed, the needle is covered by a needle shield and / or needle cover and the medicament delivery device is dispensed of.

[0007] SUMMARY

[0008] It is an object of the present invention to provide an advantageous reusable drive sub-assembly for a medicament delivery system. The reusable drive sub-assembly is configured to be removably rotationally attachable to a syringe sub-assembly between an attached configuration and a detached configuration. The reusable drive sub-assembly comprises a housing, a piston rod configured to be moved between a proximal position and a distal position, a piston rod biasing member configured to bias the piston rod into the distal position, and a clutch mechanism located in the housing and releasably rotationally lockable to the piston rod. The clutch mechanism is engageable by a mating portion of a removable syringe sub-assembly when a removable syringe sub-assembly is rotationally attached to the reusable drive subassembly. The clutch mechanism is configured to move the piston rod from its distal position to its proximal position when a removable syringe sub-assembly and the reusable drive subassembly are moved from their attached configuration to their detached configuration.

[0009] Therefore, an advantageous reusable drive sub-assembly is provided for a medicament delivery system. The reusable drive sub-assembly therefore reduces waste. Furthermore, the invention reduces the amount of force required to move the piston rod into its proximal position so that the drive sub-assembly is ready for reuse. The reduction in force required to recharge the drive subassembly makes the medicament delivery system operable for the elderly or those with a weakened grip. In addition, the invention provides for the recharging step to be completed during a normal process for removing a syringe sub-assembly from a drive sub-assembly. Therefore, the drive sub-assembly is recharged without adding an additional step for the operator to perform.

[0010] In some embodiments, the clutch mechanism may comprise a clutch housing that is fixed longitudinally with respect to the housing, a clutch body that is rotationally locked to the clutch housing, and a nut that is longitudinally locked relative to the clutch housing.

[0011] Thus, the clutch mechanism allows relative movement of the syringe sub-assembly relative to the drive sub-assembly to move the piston rod from its distal position to its proximal position during detachment of the syringe sub-assembly from the drive sub-assembly. The clutch mechanism advantageously converts rotational motion input by the operator into a linear rearward driving force on the piston rod.

[0012] In some embodiments, the clutch housing may comprise one part of a distal ratchet mechanism configured to engage with another part of the distal ratchet mechanism on the mating portion of the removable syringe sub-assembly when the reusable drive sub-assembly and the removable syringe sub-assembly are rotationally attached, wherein the distal ratchet mechanism may be configured to prevent relative rotational movement between the clutch housing and the removable syringe sub-assembly during movement from the attached configuration to the detached configuration and allow relative rotational movement between the clutch housing and the removable syringe sub-assembly during movement from the detached configuration to the attached configuration.

[0013] Thus, the distal ratchet mechanism allows the syringe sub-assembly to be attached to the drive sub-assembly without affecting the condition of the clutch housing and piston rod within the drive sub-assembly. In addition, the distal ratchet mechanism is configured to transfer the rotational motion input by an operator into rotation of the clutch mechanism to move the piston rod to its proximal position to recharge the drive sub-assembly during detachment of the syringe sub-assembly from the drive sub-assembly.

[0014] In some embodiments, the reusable drive sub-assembly may further comprise a proximal ratchet mechanism, wherein one part of the proximal ratchet mechanism is formed on the clutch housing and another part of the proximal ratchet mechanism is formed on the housing, wherein the proximal ratchet mechanism may be configured to prevent relative rotational motion of the clutch housing to the reusable drive sub-assembly in the opposing direction to the rotational movement of the removable syringe sub assembly from the attached configuration to the detached configuration

[0015] Thus, the proximal ratchet mechanism may be configured to prevent premature distal movement of the piston rod.

[0016] In some embodiments, the clutch body may be moveable between a proximal position in which the clutch body is disengaged from the nut and a distal position in which the clutch body is engaged with the nut.

[0017] Thus, clutch body may be movable to release the nut such that the piston rod can be moved distally to deliver a medicament to a patient.

[0018] In some embodiments, the clutch body may comprise a distal face gear configured to mate with a proximal face gear of the nut when the clutch body is in the distal position to prevent rotation of the nut relative to the clutch housing.

[0019] Thus, the clutch body may hold the piston rod in place to prevent unwanted to premature distal movement of the piston rod. Thus, accidental discharge of the piston rod can be prevented whilst recharging the drive sub-assembly.

[0020] In some embodiments, the clutch body may comprise at least one ramped surface on a proximally facing surface configured to engage with at least one ramped surface on the housing, wherein the ramped surfaces may be configured to move the clutch body from its disengaged position to its engaged position upon rotation of the reusable drive sub-assembly and the removable syringe sub-assembly from their attached configuration.

[0021] Thus, the clutch body may be automatically biased into engagement with the nut when the operator begins to detach the syringe sub-assembly from the drive sub-assembly. Therefore, recharging of the drive sub-assembly begins automatically upon the commencement of disengaging the syringe sub-assembly from the drive sub-assembly.

[0022] In some embodiments, the nut may be is configured to move the piston rod from the distal position to the proximal position when the reusable drive sub-assembly and the removable syringe sub-assembly are moved from their attached configuration to their detached configuration. Thus, the rotational motion of the operator detaching the syringe sub-assembly form the drive sub-assembly is translated into linear motion to recharge the drive sub-assembly. As a result, the input force required to overcome the biasing force of the piston rod biasing member is reduced. Furthermore, the clutch mechanism gearing means that a small rotational input may drive the piston rod a greater distance in the proximal direction.

[0023] In some embodiments, the nut may comprise a threaded central aperture configured to threadingly engage with a thread on the piston rod such that rotation of the nut by rotation of the reusable drive sub-assembly and the removable syringe sub-assembly from their attached configuration to their detached configuration causes proximal translation of the piston rod.

[0024] Thus, the piston rod can be held in position by the nut without any relative movement between the two. This helps to avoid an premature discharging of the drive sub-assembly.

[0025] In another aspect of the present invention, there is provided an advantageous medicament delivery device system. The medicament delivery device system comprises a reusable drive sub-assembly according to any one of claim 1 to claim 9, and a removably attachable syringe sub-assembly comprising a mating portion configured to engage the clutch mechanism when the removable attachable syringe sub-assembly is rotationally attached to the reusable drive sub-assembly.

[0026] Therefore, an advantageous medicament delivery system is provided The medicament delivery system reduces weight and the amount of force required to move the piston rod into its proximal position so that the drive sub-assembly is ready for reuse. The reduction in force required to recharge the drive sub-assembly makes the medicament delivery system operable for the elderly or those with a weakened grip. In addition, the invention provides for the recharging step to be completed during a normal process for removing a syringe sub-assembly from a drive sub-assembly. Therefore, the drive sub-assembly is recharged without adding an additional step for the operator to perform.

[0027] In some embodiments, the removable syringe sub-assembly may comprise a needle and a needle cover that is movable between an extended position, in which the needle is covered by the needle cover, and a retracted position, in which the needle is exposed, wherein the needle cover is configured to move the clutch body into the proximal position when the needle cover is in its retracted position. Therefore, the syringe sub-assembly provides a needle safety mechanism. In addition, the syringe sub-assembly is configured to release the nut so that it is free to rotate such that the piston rod can be moved distally. Thus, the needle cover may initiate the injection process when pressed against the injection site.

[0028] In some embodiments, the removable syringe sub-assembly may comprises a syringe carrier body configured to receive a disposable syringe. Thus, the syringe carrier may be reusable, which reduces waste.

[0029] In some embodiments, the removable syringe sub-assembly may comprise a disposable cassette comprising a syringe. Thus, the syringe sub-assembly may be simplified.

[0030] In some embodiments, the removable syringe sub-assembly may comprise a medicament.

[0031] In another aspect of the present invention, there is provided an advantageous method of recharging a reusable drive sub-assembly for a medicament delivery system for reuse. The method comprising the steps of rotating a reusable drive sub-assembly and a removable syringe sub-assembly relative to each other from an attached configuration to a detached configuration, engaging a clutch mechanism to rotationally lock to a piston rod, and transforming relative rotational motion of the reusable drive sub-assembly and the removable syringe sub-assembly via the clutch mechanism to translational motion of the piston rod, and moving the piston rod from a distal position to a proximal position.

[0032] Therefore, an advantageous method of recharging a reusable drive sub-assembly is provided for a medicament delivery system. The invention reduces the amount of force required to move the piston rod into its proximal position so that the drive sub-assembly is ready for reuse. The reduction in force required to recharge the drive sub-assembly makes the medicament delivery system operable for the elderly or those with a weakened grip. In addition, the method provides for the recharging step to be completed during a normal process for removing a syringe subassembly from a drive sub-assembly. Therefore, the drive sub-assembly is recharged without adding an additional step for the operator to perform.

[0033] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0035] FIGS. 1 A and 1 B show a schematic side view of an injector device with a cap attached and a cap removed

[0036] FIGS. 2A to 2C show a schematic perspective views of medicament delivery system comprising a reusable drive sub-assembly and a removable syringe sub-assembly in attached configuration and detached configurations;

[0037] FIG. 3 shows a schematic perspective exploded view of a drive sub-assembly of a medicament delivery system;

[0038] FIG. 4 shows a schematic perspective exploded view of the removable syringe sub-assembly of a medicament delivery system;

[0039] FIGS. 5A to 5E show the steps of using a medicament delivery system;

[0040] FIG. 6 shows a schematic side view of a clutch mechanism in a disengaged position with a piston rod in a distal position;

[0041] FIG. 7 shows a schematic side view of the clutch mechanism in an engaged position;

[0042] FIG. 8 shows a schematic cross-sectional side view of the clutch mechanism in the engaged position with the piston rod in a proximal position;

[0043] FIG. 9 shows a schematic cross-sectional side view of the clutch mechanism in the disengaged position;

[0044] FIG. 10 shows a schematic perspective view of a medicament delivery system comprising a cassette with a cap sub-assembly removed; and

[0045] FIGS. 11 A to 11 H show the steps of using a medicament delivery system.

[0046] DETAILED DESCRIPTION

[0047] A drug delivery device, as described herein, may be configured to inject a medicament into a patient. For example, delivery could be sub-cutaneous, intra-muscular, or intravenous. Such a device could be operated by a patient or care-giver, such as a nurse or physician, and can include various types of safety syringe, pen-injector, or auto-injector. The device can include a cartridge-based system that requires piercing a sealed ampule before use. Volumes of medicament delivered with these various devices can range from about 0.5 ml to about 2 ml. Yet another device can include a large volume device (“LVD”) or patch pump, configured to adhere to a patient’s skin for a period of time (e.g., about 5, 15, 30, 60, or 120 minutes) to deliver a “large” volume of medicament (typically about 2 ml to about 10 ml).

[0048] In combination with a specific medicament, the presently described devices may also be customized in order to operate within required specifications. For example, the device may be customized to inject a medicament within a certain time period (e.g., about 3 to about 20 seconds for auto-injectors, and about 10 minutes to about 60 minutes for an LVD). Other specifications can include a low or minimal level of discomfort, or to certain conditions related to human factors, shelf-life, expiry, biocompatibility, environmental considerations, etc. Such variations can arise due to various factors, such as, for example, a drug ranging in viscosity from about 1 cP to about 50 cP. Consequently, a drug delivery device will often include a hollow needle ranging from about 25 to about 31 Gauge in size. Common sizes are 27 and 29 Gauge.

[0049] The delivery devices described herein can also include one or more automated functions. For example, one or more of needle insertion, medicament injection, and needle retraction can be automated. Energy for one or more automation steps can be provided by one or more energy sources. Energy sources can include, for example, mechanical, pneumatic, chemical, or electrical energy. For example, mechanical energy sources can include springs, levers, elastomers, or other mechanical mechanisms to store or release energy. One or more energy sources can be combined into a single device. Devices can further include gears, valves, or other mechanisms to convert energy into movement of one or more components of a device.

[0050] The one or more automated functions of an auto-injector may each be activated via an activation mechanism. Such an activation mechanism can include one or more of a button, a lever, a needle sleeve, or other activation component. Activation of an automated function may be a one-step or multi-step process. That is, a user may need to activate one or more activation components in order to cause the automated function. For example, in a one-step process, a user may depress a needle sleeve against their body in order to cause injection of a medicament. Other devices may require a multi-step activation of an automated function. For example, a user may be required to depress a button and retract a needle shield in order to cause injection.

[0051] In addition, activation of one automated function may activate one or more subsequent automated functions, thereby forming an activation sequence. For example, activation of a first automated function may activate at least two of needle insertion, medicament injection, and needle retraction. Some devices may also require a specific sequence of steps to cause the one or more automated functions to occur. Other devices may operate with a sequence of independent steps.

[0052] Some delivery devices can include one or more functions of a safety syringe, pen-injector, or auto-injector. For example, a delivery device could include a mechanical energy source configured to automatically inject a medicament (as typically found in an auto-injector) and a dose setting mechanism (as typically found in a pen-injector).

[0053] According to some embodiments of the present disclosure, an exemplary drug delivery device 10 is shown in Figs. 1A & 1 B. Device 10, as described above, is configured to inject a medicament into a patient’s body. Device 10 includes a housing 11 which typically contains a reservoir containing the medicament to be injected (e.g., a syringe) and the components required to facilitate one or more steps of the delivery process. Device 10 can also include a cap assembly 12 that can be detachably mounted to the housing 11 . Typically a user must remove cap 12 from housing 11 before device 10 can be operated.

[0054] As shown, housing 11 is substantially cylindrical and has a substantially constant diameter along the longitudinal axis X. The housing 11 has a distal region 20 and a proximal region 21 . The term “distal” refers to a location that is relatively closer to a site of injection, and the term "proximal" refers to a location that is relatively further away from the injection site.

[0055] Device 10 can also include a needle sleeve 13 coupled to housing 11 to permit movement of sleeve 13 relative to housing 11. For example, sleeve 13 can move in a longitudinal direction parallel to longitudinal axis X. Specifically, movement of sleeve 13 in a proximal direction can permit a needle 17 to extend from distal region 20 of housing 11 .

[0056] Insertion of needle 17 can occur via several mechanisms. For example, needle 17 may be fixedly located relative to housing 11 and initially be located within an extended needle sleeve 13. Proximal movement of sleeve 13 by placing a distal end of sleeve 13 against a patient’s body and moving housing 11 in a distal direction will uncover the distal end of needle 17. Such relative movement allows the distal end of needle 17 to extend into the patient’s body. Such insertion is termed “manual” insertion as needle 17 is manually inserted via the patient’s manual movement of housing 11 relative to sleeve 13.

[0057] Another form of insertion is “automated,” whereby needle 17 moves relative to housing 11 . Such insertion can be triggered by movement of sleeve 13 or by another form of activation, such as, for example, a button 22. As shown in Figs. 1A & 1 B, button 22 is located at a proximal end of housing 11 . However, in other embodiments, button 22 could be located on a side of housing 11.

[0058] Other manual or automated features can include drug injection or needle retraction, or both.

[0059] Injection is the process by which a bung or piston 23 is moved from a proximal location within a syringe (not shown in Figures 1A and 1 B) to a more distal location within the syringe in order to force a medicament from the syringe through needle 17. In some embodiments, a drive spring (not shown in Figures 1A and 1 B) is under compression before device 10 is activated. A proximal end of the drive spring can be fixed within proximal region 21 of housing 11 , and a distal end of the drive spring can be configured to apply a compressive force to a proximal surface of piston 23. Following activation, at least part of the energy stored in the drive spring can be applied to the proximal surface of piston 23. This compressive force can act on piston 23 to move it in a distal direction. Such distal movement acts to compress the liquid medicament within the syringe, forcing it out of needle 17.

[0060] Following injection, needle 17 can be retracted within sleeve 13 or housing 11. Retraction can occur when sleeve 13 moves distally as a user removes device 10 from a patient’s body. This can occur as needle 17 remains fixedly located relative to housing 11 . Once a distal end of sleeve 13 has moved past a distal end of needle 17, and needle 17 is covered, sleeve 13 can be locked. Such locking can include locking any proximal movement of sleeve 13 relative to housing 11.

[0061] Another form of needle retraction can occur if needle 17 is moved relative to housing 11 . Such movement can occur if the syringe within housing 11 is moved in a proximal direction relative to housing 11 . This proximal movement can be achieved by using a retraction spring (not shown), located in distal region 20. A compressed retraction spring, when activated, can supply sufficient force to the syringe to move it in a proximal direction. Following sufficient retraction, any relative movement between needle 17 and housing 11 can be locked with a locking mechanism. In addition, button 22 or other components of device 10 can be locked as required.

[0062] Referring now to FIGS. 2A to 2C, a schematic perspective side view of an embodiment of a medicament delivery system 100 is shown. The medicament delivery system 100 is a medicament delivery device with a reusable portion and a consumable or replaceable portion.

[0063] The medicament delivery system 100 comprises a reusable drive sub-assembly 101 and a removable syringe sub-assembly 102. The reusable drive sub-assembly 101 is configured to be removably rotationally attachable to the removable syringe sub-assembly 102. The reusable drive sub-assembly 101 and the removable syringe sub-assembly 102 are configured to be moved between an attached configuration and a detached configuration. The medicament delivery system 100 may further comprise a removably replaceable cap assembly 103. The removably replaceable cap sub-assembly 103 may be configured to be removed and reattached to a distal end of the removable syringe sub-assembly 102. Referring to FIG. 2A, the medicament delivery system 100 may be provided in the detached configuration. That is, the medicament delivery system 100 may be provided in a state where the removable syringe sub-assembly 102 is detached from the reusable drive sub-assembly 101. In the detached configuration, the cap sub-assembly 103 may be attached to the removable syringe sub-assembly 102.

[0064] Referring to FIG. 2B, the medicament delivery system 100 may be placed into its attached configuration by attaching the removable syringe sub-assembly 102 to the reusable drive subassembly 101. As previously discussed, the removable syringe sub-assembly 102 may be attached to the reusable drive sub-assembly 101 by twisting the two sub-assemblies 101 , 102 together. In the attached configuration, the cap sub-assembly 103 may be at least initially attached to the removable syringe sub-assembly 102.

[0065] Referring to FIG. 2C, when the medicament delivery system 100 is to be used, the reusable drive sub-assembly 101 and the removable syringe sub-assembly 102 are kept in the attached configuration and the cap sub-assembly 103 is removed. The cap sub-assembly 103 may be replaced on the removable syringe sub-assembly 102 after use. The removable syringe subassembly 102 may then be removed from the reusable drive sub-assembly 101 to the detached configuration, as shown in FIG. 2A.

[0066] Referring now to FIG. 3, a schematic perspective exploded view of the reusable drive subassembly 101 is shown. The reusable drive sub-assembly 101 comprises a housing 111 , a piston rod 121 configured to be moved between a proximal position P’ and a distal position D’, and a piston rod biasing member 122 configured to bias the piston rod 121 into the distal position D’. The reusable drive sub-assembly 101 further comprises a clutch mechanism 131 located in the housing 111 and releasably rotationally lockable to the piston rod 121 .

[0067] The housing 111 may be configured to house the other components of the reusable drive subassembly 101. The housing 111 may be generally tubular having an empty internal volume 112 for receiving the other components of the reusable drive sub-assembly 101. As shown in FIG. 3, the housing 111 may be generally cylindrical, although it will be appreciated that in other embodiments the housing 111 may have any hollow shape.

[0068] The reusable drive sub-assembly 101 may further comprise an end cap 113. The end cap 113 may be located at the proximal end of the housing 111. The end cap 113 may be configured to close a proximal end P of the housing 111. The end cap 113 may be a separate component or may be integrally formed with the housing 111.

[0069] The housing 111 may further comprise at least one guide 114, shown in dotted lines in FIG. 3. The at least one guide 114 may be configured to limit movement of the piston rod 121 to linear translational motion between its proximal P’ and distal D’ positions. The at least one guide 114 may comprise a first wall 115 and a second wall 116 spaced apart by a gap 117. The first and second walls 115, 116 may extend longitudinally parallel to the longitudinal axis of the housing 111. The first and second walls 115, 116 may extend from an inner surface of the housing 111. The first and second walls 115, 116 may extend generally towards the centre of the housing 111. The housing 111 may comprise two guides 114. The two guides 114 may be spaced apart around the inner surface of the housing 111. The two guides 114 may be diametrically opposed. Thus, the two guides 114 may prevent any rotational motion of the piston rod 121.

[0070] The housing 111 may further comprise a first recess 118 formed in its inner surface. The first recess 118 may be configured to receive a cooperating portion of the clutch body 132 to longitudinally lock the clutch mechanism 131 with respect to the housing 111. The first recess 118 may extend continuously in the circumferential direction around the inner surface of the housing 111.

[0071] The housing 111 may further comprise a second recess 119 formed its inner surface. The second 119 may be configured to receive a clutch mechanism 131. The second recess 119 may be a discrete recess. The second recess 119 may be configured to prevent, or at least restrict, longitudinal movement of the clutch mechanism 131 relative to the housing 111. Furthermore, the second recess 119 may be configured to form a part of a ratchet mechanism with the clutch mechanism 131 , as will be explained in more detail hereinafter. It will be appreciated that the housing 111 may comprise a plurality of second recesses 119.

[0072] The housing 111 may further comprise a ramped surface 120, shown in dotted lines in FIG. 3. The ramped surface 120 may extend inwardly from the inner surface of the housing 111. The ramped surface 120 may be configured to engage the clutch body 133 when the reusable drive sub-assembly 101 and removable syringe sub-assembly 102 are moved from their attached configuration to their detached configuration, as will be explained in more detail hereinafter.

[0073] The housing 111 may further comprise an internal thread 181. The internal thread 181 may be configured to cooperate with a thread on the removable syringe sub-assembly 102 to attached the reusable drive sub-assembly 101 to the removable syringe sub-assembly 102. The internal thread 181 may be located at the distal end of the housing 111 and extend proximally.

[0074] The piston rod 121 is configured to be moved between a proximal position P’ and a distal position D’, as will be explained in more detail hereinafter. When the piston rod 121 is in the proximal position, the majority, if not all, of the piston rod 121 may be received in the housing 111 of the reusable drive sub-assembly 101. When the piston rod 121 is in the distal position, the majority of the piston rod 121 may extend from the housing 111 of the reusable drive subassembly 101. The piston rod 121 may be generally cylindrical and elongate.

[0075] The piston rod 121 may comprise a main body 124. The main body 124 may be cylindrical and elongate. The piston rod 121 may be configured to contact a bung or piston of the removable syringe sub-assembly 102, as will be explained in more detail hereinafter. The main body 124 of the piston rod 121 may comprise a thread 125. The thread 125 may extend around the outer surface of the cylindrical main body 124 of the piston rod 121. The thread 125 may extend along the majority of the length of the piston rod 121. The thread 124 may begin at the distal end of the piston rod 121 and extend proximally.

[0076] The piston rod 121 may further comprise at least one projection 127. The at least one projection 127 may extend radially from the proximal end of the piston rod 121. That is, the at least one projection 127 may extend perpendicularly from the main body 124 of the piston rod 121. The at least one projection 127 may be configured to extend between the first and second walls 116, 117 of the at least one guide 115 in order to prevent rotational motion of the piston rod 121 with respect to the housing 111 of the reusable drive sub-assembly 101. The piston rod 121 may comprise two projections 127. The two projections 127 may be diametrically opposed on the piston rod 121 . The two projections 127 may be configured to extend between the first and second guide walls 115, 116 of the two guides 114, respectively.

[0077] The piston rod biasing member 122 may be a coil spring 122. The piston rod biasing member 122 may extend coaxially with the piston rod 121 . The piston rod 121 may comprise an internal bore 129. The internal bore 129 may have an open end at the proximal end of the piston rod 121 and a closed end. The piston rod biasing member 122 may be configured to extend into the internal bore 129 of the piston rod 121.

[0078] The clutch mechanism 131 is configured to move the piston rod 121 from its distal position D’ to its proximal position P’ when the removable syringe sub-assembly 102 and the reusable drive sub-assembly 101 are moved from their attached configuration to their detached configuration. The clutch mechanism 131 may comprise a clutch housing 132, a clutch body 133, and a nut 134. The clutch housing 132 may be fixed longitudinally with respect to the housing 111. The clutch body 122 may be rotationally locked to the clutch housing 132. The nut 134 may be longitudinally locked relative to the clutch housing 132. The clutch body 133 may be at least partially received within the clutch housing 132. The nut 134 may be located between the clutch housing 132 and the clutch body 133.

[0079] The clutch housing 132 may comprise a distal rachet mechanism 141. The distal ratchet mechanism 141 may comprise a first ratchet 142 and a first mating portion 143. The first mating portion 143 may be a first pawl 143. The first pawl 143 may be spring loaded or may be a resiliently deformable pawl 143. A part of the distal ratchet mechanism 141 may be located on the clutch housing 132. That is, one of the first rachet 142 and the first pawl 143 may be located on a distally facing surface of the clutch housing 132, and the other of the first rachet 142 and the first pawl 143 may be located on a mating portion 144 of the removable syringe subassembly 102.

[0080] The distal ratchet mechanism 141 may be configured to prevent relative rotational movement between the clutch housing 132 and the removable syringe sub-assembly 102 during movement from the attached configuration to the detached configuration. The distal ratchet mechanism 141 may be configured to allow relative rotation movement between the clutch housing 132 and the removable syringe sub-assembly 102 during movement from the detached configuration to the attached configuration.

[0081] The clutch housing 132 may further comprise a proximal rachet mechanism 145. The proximal ratchet mechanism 145 may comprise a second ratchet 146 and a second mating portion 147. The second mating portion 146 may be a second pawl 147. The second pawl 147 may be a resiliently deformable pawl 147, as shown in FIG. 3. However, in other embodiments, the second pawl 147 may be spring loaded. In the illustrated embodiment, the second pawl 147 is located on the clutch body 132 and the second ratchet 146 is formed on the housing 111 of the reusable drive sub-assembly 101. More specifically, in the illustrated embodiments, the second ratchet 146 is formed by a side wall of the second recess 119 formed in the inner surface of the housing 111 , as will be explained in more detail hereinafter. However, it will be appreciated that in alternative embodiments, the second ratchet 146 may be formed on the clutch housing 132 and the second pawl 147 may be formed on the inner surface of the housing 111.

[0082] The proximal ratchet mechanism 145 may be configured to prevent relative rotational motion of the clutch housing 132 to the reusable drive sub-assembly 101 in the opposing direction to the rotational movement of the removable syringe sub-assembly 102 from the attached configuration to the detached configuration. That is, the proximal ratchet mechanism 145 may be configured to prevent rotation of the clutch housing 132 under force from the piston rod biasing member 122 attempting to bias the piston rod 131 into the distal position, as will be explained in more detail hereinafter.

[0083] The clutch housing 132 may comprise a tubular section 151. The tubular section 151 may comprise a central aperture 152. The central aperture 142 may be configured to allow the piston rod 121 to pass through the clutch housing 132 as the piston rod 121 is moved between its proximal and distal positions. The distal end of the tubular section 151 may comprise a part of the distal ratchet mechanism 141. For example, the distal end of the tubular section 151 may comprise the first ratchet or the first pawl.

[0084] The clutch housing 132 may further comprise at least one radially extending arm 153, most clearly shown in FIGS. 7 and 8. The radially extending arms 153 may extend perpendicularly to the longitudinal axis of the reusable drive sub-assembly 101. The radially extending arms 153 may extend from the outer surface of the tubular section 151. The clutch housing 132 may comprise a plurality of radially extending arms 153. For example, the clutch housing 132 may comprise two radially extending arms 153. The two radially extending arms 153 may be diametrically opposed.

[0085] The clutch housing 132 may further comprise an annular wall 154. The annular wall 154 may extend from an outer edge of the radially extending arms 153. The annular wall 154 may extend perpendicularly to the radially extending arms 153. That is, the annular wall 154 may extend parallel, and coaxially, with the longitudinal axis of the tubular section 151 and the housing 111. The annular wall 154 may extend at least in the proximal direction. The annular wall 154 may extend around the tubular section 151 circumferentially. Thus, the radially extending arm(s) 153 may be configured to provide a space between the tubular section 151 and the annular wall 154 for the clutch body 133 and the nut 134 to be received in.

[0086] The annular wall 154 may comprise at least one cut-out section 155. The cut-out section 154 may extend from a proximal end of the annular wall 154 distally towards the radially extending arms 153.

[0087] The clutch housing 132 may further comprise a clip 156. The clip 156 may be configured to rotationally lock the clutch body 133 relative to the clutch housing 132. The clip 156 may be configured to allow a predetermined amount of longitudinal movement between the clutch housing 132 and the clutch body 133, as will be described in more detail hereinafter. The clip 156 may extend from the distal end of the cut-out section 155 in the annular wall 154 and extend proximally. The clip 156 may comprise a stalk portion 157 that extends from the distal end of the cut-out section 155 and a barb portion 158 located at the proximal end of the stalk portion 157. The barb portion 158 may be dimensioned such that it wider distal end can latch over a corresponding feature of the clutch body 133 and prevent the clutch body 133 being moved beyond the predetermined longitudinal distance. The stalk portion 157 may be dimensioned so as to allow for a predetermined amount of movement of the clutch body 133 relative to the clutch housing 132 in the longitudinal direction.

[0088] The clutch housing 132 may comprise two cut-out sections 155. The clutch housing 132 may comprise two clips 156. Each of the cut-out sections 155 may comprise a clip 156.

[0089] The clutch housing 132 may further comprise a part of the proximal ratchet mechanism 145, as previously described. That is, the clutch housing 132 may comprise a second mating portion 147 or second pawl 147. The second pawl 147 may be formed on the outer circumferential surface of the annular wall 154. The second pawl 147 may be biased outwards from the annular wall 154 and configured to engage with the second ratchet 146, i.e. second recess 119, in the housing 111. The clutch housing 132 may comprise two second pawls 147. The two second pawls 147 may be diametrically opposed. The two second pawls 147 may be configured to engage the two second recesses 119 simultaneously.

[0090] Although the illustrated embodiment only illustrates two second pawls, it will be appreciated that any number of second pawls 147 may be provided. The second pawls 147 may be equidistantly located around the outer surface of the annular wall 154 of the clutch housing 142. Therefore, the amount of backlash in the medicament delivery system 100 can be reduced when moving the removable syringe sub-assembly and the reusable drive sub-assembly from the attached configuration to the detached configuration. Furthermore, any number of second recesses 119 may be provided.

[0091] The clutch housing 132 may further comprise a rib 159. The rib 159 may extend outwardly from the outer surface of the annular wall 154 of the clutch housing 132. The rib 159 may extend continuously in the circumferential direction around the outer surface of the annular wall 154. The rib 159 may be configured to be located in the circumferentially extending first recess 118 in the inner surface of the housing 111. The clutch body 133 may be configured to be moveable between a proximal position and a distal position. In the proximal position, the clutch body 133 may be disengaged from the nut 134. When the clutch body 133 is disengaged from the nut 134, the nut 134 may rotationally free with respect to the rest of the clutch mechanism 131. In the distal position, the clutch body 133 may be engaged with the nut 134. When the clutch body 133 is engaged with the nut 134, the nut 134 may be rotationally locked with respect to the rest of the clutch mechanism 131.

[0092] The clutch body 133 may comprise an annular plate 161. The annular plate 161 may extend perpendicularly to the longitudinal axis of the reusable drive sub-assembly 101. The annular plate 161 may comprise a central aperture 162. The central aperture 162 may be configured to allow the piston rod 121 to pass through the clutch body 133 as the piston rod 121 is moved between its proximal and distal positions.

[0093] The clutch body 133 may comprise a distal face gear 163. The distal face gear 163 may be configured to engage the nut 134 when the clutch body 133 is in its distal position. The distal face gear 163 may be located on the distal surface of the annular plate 161. The distal face gear 163 may be generally annular in shape and may extend around the central aperture 162 in the annular plate 161. The distal face gear 163 may surround the central aperture 162. The distal face gear 163 may comprise a plurality of teeth 164. The plurality of teeth 164 may be configured to mate with a cooperating feature on the nut 134 when the clutch body 133 is in its distal position.

[0094] The clutch body 133 may further comprise at least one ramped surface 165. The at least one ramped surface 165 may comprise a first portion and a second portion. The second portion of the at least one ramped surface 165 may be located closer to the proximal end of the reusable drive sub-assembly 101 than the first portion. The at least one ramped surface 165 may be inclined from the first portion to the second portion. The incline of the at least one ramped surface 165 may be linear or non-linear.

[0095] The at least one ramped surface 165 may be located on a proximally facing surface of the clutch body 133. For example, the at least one ramped surface 165 may be located on the proximal surface of the annular plate 161. Alternatively, as shown in FIG. 5, the at least one ramped surface 165 may be cut into the peripheral edge of the proximal surface of the annular plate 161. The at least one ramped surface 165 may extend in the circumferential direction around the clutch body 133. The at least one ramped surface 165 of the clutch body 133 may be configured to engage with the at least one ramped surface 120 of the housing 111 of the reusable drive sub-assembly 101. That is, the at least one ramped surface 165 of the clutch body 133 may engage the at least one ramped surface 120 of the housing 111 when the clutch body 133 is in its proximal, disengaged position. The ramped surfaces 120, 165 may be configured to move the clutch body 133 from its proximal disengaged position to its distal engaged position upon rotation of the reusable drive sub-assembly 101 and removable syringe sub-assembly 102 from their attached configuration towards their detached configuration, as will be explained in more detail hereinafter. It will be appreciated that the clutch body 133 may comprise a plurality of ramped surfaces 165 that extend circumferentially around the clutch body 133.

[0096] The clutch body 133 my further comprise an annular wall 167. The annular wall 167 may extend from an outer edge of the annular plate 161. The annular wall 167 may extend perpendicularly to the annular wall 167. That is, the annular wall 167 may extend parallel, and coaxially, with the longitudinal axis of the housing 111. The annular wall 167 may extend distally from the annular plate 161. The annular wall 167 may be configured to be located within the annular wall 154 of the clutch housing 132. The annular wall 167 of the clutch body 133 and the annular wall 154 of the clutch housing 132 may be dimensioned so as to form an interference fit. Therefore, the clutch body 133 may be prevented from moving freely between its distal and proximal positions.

[0097] The annular wall 167 of the clutch body 133 may comprise at least one cut-out section 168. The at least one cut-out section 168 may extend from a distal end of the annular wall 167 in a proximal direction towards the annular plate 161 . The at least one cut-out section 168 in the annular wall 167 of the clutch body 167 may be configured to receive one of the radially extending arms 153 of the clutch housing 132.

[0098] The clutch body 133 may further comprise a locking element 169. The locking element 169 may be configured to receive the barb portion 158 of the clip 156 on the clutch housing 132. The locking element 169 may be located on an outer circumferential surface of the annular wall 167 of the clutch body 133. The locking element 169 may be located at the proximal end of the cutout section 168 of the clutch housing 133. The locking element 169 may comprise a locking feature (not shown) that is configured to mate with the distal end of the barb portion 158 of the clip 156 to limit relative longitudinal motion between the clutch body 133 and the clutch housing 132. The locking element 169 may allow a predetermined amount of longitudinal movement between the clutch body 133 and the clutch housing 132 in order to allow the clutch body 133 to move between its proximal and distal positions. The nut 134 may be configured to move the piston rod 121 from its distal position to its proximal position when the reusable drive sub-assembly 102 are moved from their attached configuration to their detached configuration.

[0099] The nut 134 may comprise a central aperture 171. The central aperture 171 of the nut 134 may be configured to allow the piston rod 121 to pass through the nut 134 as the piston rod 121 is moved between it proximal and distal positions. The central aperture 171 of the nut 134 may comprise a thread 172. The thread 172 may extend around the surface of the central aperture 171. The thread 172 may extend along the length of the central aperture 171. The thread 172 of the nut 134 may be configured to cooperate, or threadingly engage, with the thread 125 of the piston rod 121. The threaded central aperture 171 of the nut 134 may be configured such that rotation of the nut 134, caused by rotation of the reusable drive sub-assembly 101 and the removable syringe sub-assembly 102 from their attached configuration to their detached configuration, causes proximal translation of the piston rod 121.

[0100] The nut 134 may further comprise a proximal face gear 174. The proximal face gear 174 may be configured to engage the clutch body 133, or more specifically the distal face gear 163 of the clutch body 133, when the clutch body 133 is in its distal position. The proximal face gear 174 may be located on the proximal surface of the nut 134. The proximal face gear 174 may be generally annular in shape and may extend around the central aperture 171. The proximal face gear 174 may extend around the central aperture 171 of the nut 134. The proximal face gear 174 may comprise a plurality of teeth 175. The plurality of teeth 175 may be configured to mate with the plurality of teeth 164 on the distal face gear 163 of the clutch body 133, when the clutch body 133 is in its distal position.

[0101] Referring now to FIG. 4, a perspective schematic exploded view of the removable syringe subassembly 102 and cap sub-assembly 103 is shown. In the illustrated embodiment, the removable syringe sub-assembly 102 comprises a pre-filled syringe carrier body 201. The prefilled syringe carrier body 201 may be configured to receive a pre-filled syringe 202. The prefilled syringe 202 may comprise a syringe 203 storing a medicament, a plug or piston (not shown) located in proximal region of the syringe 203, and a needle (not shown) located at the distal end of the syringe 203.

[0102] The pre-filled syringe carrier body 201 may further comprise a part of the distal ratchet mechanism 141. That is, the pre-filled syringe carrier body 201 may comprise one of the first ratchet 142 and the first mating portion 143, or pawl 143. The part of the distal ratchet mechanism 141 may be located at, or proximate to, the proximal end of the pre-filled syringe carrier body 201 so that it can engage with the other part of the distal ratchet mechanism 141 located on the clutch housing 132.

[0103] The removable syringe sub-assembly 102 may further comprise a needle cover 206 and a needle cover biasing member 207. The needle cover 206 may be configured to be moved between an extended position, in which it extends from the distal end of the pre-filled syringe carrier body 201 to cover a needle, and a retracted position, in which the needle is exposed. The needle cover biasing member 207 may be configured to bias the needle cover 206 into the extend position. The needle cover biasing member 207 may be a coil spring 207.

[0104] The needle cover 206 may comprise a cover portion 208 and at least one arm 209. The cover portion 208 may be configured to cover the needle when the needle cover 206 is in its extended position. The at least one arm 209 may extend proximally from the cover portion 208 of the needle cover 209. As illustrated, the needle cover 206 may comprise two arms 209. The two arms 209 may be located diametrically opposite one another.

[0105] The removeable syringe sub-assembly 102 may further comprise a pair of needle levers 211. The pair of needle levers 211 may be configured to be deflected radially when a pre-filled syringe 203 is placed into the pre-filled syringe carrier body 201 to engage a needle cover lock (now shown).

[0106] The cap sub-assembly 103 may comprise a cap 221. The cap 221 may be configured to close the distal end of the removeable syringe sub-assembly 102 before or after use. The cap subassembly 103 may further comprise a removable needle shield 222. The removable needle shield 222 may be configured to shield the needle of the removable syringe sub-assembly 102 when a pre-filled syringe 202 is present in the pre-filled syringe carrier body 210 before and after use. The needle shield 222 may be removable from the removable syringe sub-assembly 102 with the cap 221 before use. In addition, the needle shield 222 may be replaceable on the removable syringe sub-assembly 102 with the cap 221 after use. The needle shield 222 may comprise a locking mechanism (not shown) such that once it has been replaced on the removable syringe sub-assembly 102 it cannot be removed from the needle. Thus, accidental reuse of the needle may be prevented.

[0107] The syringe carrier body 201 may further comprise an external thread 215. The external thread 215 may be configured to cooperate with the internal thread 181 on the housing 111 of the reusable drive subassembly 101 to attached the removable syringe sub-assembly 102 to the reusable drive sub-assembly 101. The external thread 215 may be located at a proximal end of the carrier body 201 and extend distally.

[0108] Referring now briefly to FIGS. 5A to 5M, a schematic overview of the method of use of the medicament delivery system 100 is shown. The operator of the medicament delivery system

[0109] 100 begins by removing the medicament delivery system 100 from storage, as shown in FIG. 5A. The operator also take a syringe 203 from storage, shown in FIG. 5B, and then precedes to twist the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101 to open the medicament delivery system 100, as shown in FIG. 5C.

[0110] Referring now to FIG. 6, a schematic perspective side view of the reusable drive sub-assembly

[0111] 101 is shown. The reusable drive sub-assembly 101 is shown with the components in their positions when the medicament delivery system 100 is removed from storage for the first time. Upon first use, the piston rod 121 may be located in the distal position. This reduces load on the piston rod biasing member 122 during storage. Thus, the lifespan of the piston rod biasing member 122, and therefore overall device, is increased. The clutch body 133 is in its proximal position.

[0112] Upon relative rotation of the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101 , the first ratchet 142 on the pre-filled syringe carrier body 201 engages with the pawl 143 on the clutch housing 132 to rotationally lock the removable syringe sub-assembly

[0113] 102 to the clutch housing 132 in the direction of rotation from the attached configuration to the detached configuration. The direction of rotation from the attached configuration to the detached configuration may be anticlockwise when viewed from the distal end of the removable syringe sub-assembly 102.

[0114] Due to the clutch housing 132 being rotationally locked to the clutch body 133, rotation of the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101 causes the clutch body 133 to rotate. As the clutch body 133 rotates, the at least one ramped surface 165 of the clutch body 133 slides against the at least one ramped surface 120 of the housing 111 of the reusable drive sub-assembly 101. The sliding of the ramped surface 165 of the clutch body 133 over the ramped surface 120 of the housing 111 causes the clutch body 133 to move distally within the clutch body 132.

[0115] Distal movement of the clutch body 133 relative to the clutch housing 132 causes the clutch body 133 to move from its proximal disengaged position, shown in FIG. 6, to its distal, engaged position, shown in FIGS. 7 and 8, where the clutch body 133 engages the nut 134. That is, when the clutch body 133 is moved into its distal, engaged position, the teeth 164 of the distal face gear 163 of the clutch body 133 engage with the teeth 175 of the proximal face gear 174 of the nut 134. The distal movement of the clutch body 133 into the engaged position rotationally locks the clutch body 133 to the nut 134.

[0116] Further rotation of the removable syringe sub-assembly 102 relative to the reusable drive subassembly 101 in the direction of rotation from the attached configuration to the detached configuration, causes the nut 134 to rotate. Due to the threaded engagement of the nut 134 and the piston rod 121 and the limitation on rotation of the piston rod 121 by the guides 114 in the housing 111 , the piston rod 121 is forced to move proximally within the housing 111 from its distal position, which compresses the piston rod biasing member 122 in the process. Thus, the medicament delivery system 100 is primed for reuse by the untwisting of the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101.

[0117] When the operator removes a hand from one of the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101 , the force from the piston rod biasing member 122 will attempt to push the piston rod 121 distally, and thus attempt to turn the clutch mechanism 131 in the opposite direction, which would rotate the removable syringe subassembly 102 relative to the reusable drive sub-assembly 101 back towards the attached configuration. However, the pawl 147 of the proximal ratchet mechanism engages in the second ratchet 146 or second recess 119 of the housing 111 to prevent any counter rotation due to the force of the piston rod biasing member 122.

[0118] The number of revolutions required to move the removable syringe sub-assembly 102 relative to the reusable drive sub-assembly 101 from their attached configuration to their detached configuration may equal the number of revolutions required to move the piston rod 121 from its distal position to its proximal position. Therefore, the reusable drive sub-assembly 101 may be (re-)primed by the action of detaching the removable syringe sub-assembly 102 from the reusable drive sub-assembly 101. The number of revolutions required to detach the removable syringe sub-assembly 102 and the reusable drive sub-assembly 101 and / or move the piston rod 121 from its distal position to its proximal position may be in the range of 4 to 6.

[0119] Based on the previous description of recharging the reusable drive sub-assembly 101 , it is clear that the method comprises the steps of rotating the reusable drive sub-assembly 101 and the removable syringe sub-assembly 102 relative to each other from an attached configuration to a detached configuration; engaging the clutch mechanism 131 to rotationally lock to the piston rod 121 ; and transforming the relative rotational motion of the reusable drive sub-assembly 101 and the removable syringe sub-assembly 102 via the clutch mechanism 131 to translational motion of the piston rod 121 ; and moving the piston rod 121 from a distal position to a proximal position.

[0120] Referring back to FIG. 5D, the operator then places the syringe 203 into the pre-filled syringe carrier body 201 . The operator then reattaches the removable syringe sub-assembly 102 to the reusable drive sub-assembly 101 by twisting them relative to each other in the opposite direction to the direction for twisting them apart, as shown in FIG. 5E. During the process of attaching the removable syringe sub-assembly 102 to the reusable drive sub-assembly 101 , the distal ratchet mechanism 141 allows the removable syringe sub-assembly 102 to rotate relative to the clutch mechanism 131.

[0121] Once the medicament delivery system 100 is in its attached configuration, the operator may remove the cap sub-assembly 103 from the distal end of the removable syringe sub-assembly 102, as shown in FIG. 5F. Then, the operator may perform an injection by pressing the distal end of the removable syringe sub-assembly 102 against a patient’s skin, as shown in FIG. 5G. As the operator presses the distal end of the removable syringe sub-assembly 102 against the patient’s skin, the needle cover 206 may be pushed proximally from its extended position into its retracted position against the biasing force of the needle cover biasing member 207.

[0122] Referring briefly to FIG. 9, the proximal movement of the needle cover 206 causes the proximal end of the arms 209 of the needle cover 206 to abut against the distal end of the clutch body 133, more specifically the distal end of the annular wall 167 of the clutch body 133, and move the clutch body 133 from its distal engaged position to its proximal, disengaged position. By moving the clutch body 133 into its disengaged position, the nut 134 become free to rotate. Thus, the piston rod 121 is able to move distally under the force of the piston rod biasing member 122 because the nut 134 is no longer rotationally locked.

[0123] Referring back to FIG. 5H, once the injection has been completed, the operator may remove the medicament delivery system 100 from the patient’s skin. The needle cover 206 may be biased back into its extended position to cover the needle and the cap sub-assembly 103 may be replaced onto the removable syringe sub-assembly 102.

[0124] Referring to FIG. 5I, the operator may then twist open the medicament delivery system 100 again, and in the process move the piston rod 121 from its distal position to its proximal position to prepare the reusable drive sub-assembly 101 for another injection. One the medicament delivery system 100 is in its detached configuration, the operator may then remove the syringe 203, see FIG. 5J, and dispose of the syringe 203, see FIG. 5K, before closing the medicament delivery system 100, see FIG. 5L, and placing it into storage, see FIG. 5M.

[0125] Referring briefly to FIG. 10, another embodiment of the removable syringe sub-assembly 102 is shown. In the illustrated embodiment, the removable syringe sub-assembly 102 comprises a cassette 301 . The cassette 301 may comprise all the features and components of the removable syringe sub-assembly 102 and cap sub-assembly 103, including a pre-filled syringe 203, combined into one disposable consumable component. It will be appreciated that the operation and sequence of steps of the reusable drive sub-assembly 101 will be the same as described above in conjunction with a syringe carrier body 201 type syringe sub-assembly 102.

[0126] Referring briefly to FIG. 11 A to 11 H, the operator may remove the reusable drive sub-assembly 101 from storage, see FIG. 11 A, and remove a cassette 310 from storage, see FIG. 11 B. The operator may then twist the cassette 301 onto the reusable drive sub-assembly 101 , see FIG.

[0127] 11 C, before removing the cap 221 of the cassette 301 , see FIG. 11 D. The operator may the perform the injection, see FIG. 11 E, before twisting open the medicament delivery system 100, see FIG. 11 F, before disposing of the cassette 301 , see FIG. 11G, and placing the reusable drive sub-assembly 101 into storage, see FIG. 11 H.

[0128] The terms “drug” or “medicament” are used synonymously herein and describe a pharmaceutical formulation containing one or more active pharmaceutical ingredients or pharmaceutically acceptable salts or solvates thereof, and optionally a pharmaceutically acceptable carrier. An active pharmaceutical ingredient (“API”), in the broadest terms, is a chemical structure that has a biological effect on humans or animals. In pharmacology, a drug or medicament is used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. A drug or medicament may be used for a limited duration, or on a regular basis for chronic disorders.

[0129] As described below, a drug or medicament can include at least one API, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Examples of API may include small molecules having a molecular weight of 500 Da or less; polypeptides, peptides and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes); carbohydrates and polysaccharides; and nucleic acids, double or single stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids may be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more drugs are also contemplated. The drug or medicament may be contained in a primary package or “drug container” adapted for use with a drug delivery device. The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., shorter long-term storage) of one or more drugs. For example, in some instances, the chamber may be designed to store a drug for at least one day (e.g., 1 to at least 30 days). In some instances, the chamber may be designed to store a drug for about 1 month to about 2 years. Storage may occur at room temperature (e.g., about 20°C), or refrigerated temperatures (e.g., from about - 4°C to about 4°C). In some instances, the drug container may be or may include a dualchamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and / or during dispensing into the human or animal body. For example, the two chambers may be configured such that they are in fluid communication with each other (e.g., by way of a conduit between the two chambers) and allow mixing of the two components when desired by a user prior to dispensing. Alternatively or in addition, the two chambers may be configured to allow mixing as the components are being dispensed into the human or animal body.

[0130] The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and / or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and / or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as Rote Liste 2014, for example, without limitation, main groups 12 (antidiabetic drugs) or 86 (oncology drugs), and Merck Index, 15th edition.

[0131] Examples of APIs for the treatment and / or prophylaxis of type 1 or type 2 diabetes mellitus or complications associated with type 1 or type 2 diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-1), GLP-1 analogues or GLP-1 receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-4 (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms “analogue” and “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and / or exchanging at least one amino acid residue occurring in the naturally occurring peptide and / or by adding at least one amino acid residue. The added and / or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as "insulin receptor ligands". In particular, the term ..derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g., a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide may have been deleted and / or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide.

[0132] Examples of insulin analogues are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin (insulin glulisine); Lys(B28), Pro(B29) human insulin (insulin lispro); Asp(B28) human insulin (insulin aspart); human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Vai or Ala and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin.

[0133] Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); B29-N- palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl- ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-gamma-glutamyl)-des(B30) human insulin, B29-N-omega- carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(w- carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(w-carboxyheptadecanoyl) human insulin.

[0134] Examples of GLP-1 , GLP-1 analogues and GLP-1 receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-4, Byetta®, Bydureon®, a 39 amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), rExendin-4, CJC- 1134-PC, PB-1023, TTP-054, Langlenatide / HM-11260C (Efpeglenatide), HM-15211 , CM-3, GLP-1 Eligen, ORMD-0901 , NN-9423, NN-9709, NN-9924, NN-9926, NN-9927, Nodexen, Viador-GLP-1 , CVX-096, ZYOG-1 , ZYD-1 , GSK-2374697, DA-3091 , MAR-701 , MAR709, ZP- 2929, ZP-3022, ZP-DI-70, TT-401 (Pegapamodtide), BHM-034. MOD-6030, CAM-2036, DA- 15864, ARI-2651 , ARI-2255, Tirzepatide (LY3298176), Bamadutide (SAR425899), Exenatide- XTEN and Glucagon-Xten.

[0135] An example of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia or RG012 for the treatment of Alport syndrome.

[0136] Examples of DPP4 inhibitors are Linagliptin, Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine.

[0137] Examples of hormones include hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, and Goserelin.

[0138] Examples of polysaccharides include a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra-low molecular weight heparin or a derivative thereof, or a sulphated polysaccharide, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and / or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium. An example of a hyaluronic acid derivative is Hylan G-F 20 (Synvisc®), a sodium hyaluronate.

[0139] The term “antibody”, as used herein, refers to an immunoglobulin molecule or an antigenbinding portion thereof. Examples of antigen-binding portions of immunoglobulin molecules include F(ab) and F(ab')2 fragments, which retain the ability to bind antigen. The antibody can be polyclonal, monoclonal, recombinant, chimeric, de-immunized or humanized, fully human, non-human, (e.g., murine), or single chain antibody. In some embodiments, the antibody has effector function and can fix complement. In some embodiments, the antibody has reduced or no ability to bind an Fc receptor. For example, the antibody can be an isotype or subtype, an antibody fragment or mutant, which does not support binding to an Fc receptor, e.g., it has a mutagenized or deleted Fc receptor binding region. The term antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and / or a dual variable region antibody-like binding protein having cross-over binding region orientation (CODV).

[0140] The terms “fragment” or “antibody fragment” refer to a polypeptide derived from an antibody polypeptide molecule (e.g., an antibody heavy and / or light chain polypeptide) that does not comprise a full-length antibody polypeptide, but that still comprises at least a portion of a full- length antibody polypeptide that is capable of binding to an antigen. Antibody fragments can comprise a cleaved portion of a full length antibody polypeptide, although the term is not limited to such cleaved fragments. Antibody fragments that are useful in the present invention include, for example, Fab fragments, F(ab')2 fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, tetraspecific and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), monovalent or multivalent antibody fragments such as bivalent, trivalent, tetravalent and multivalent antibodies, minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art.

[0141] The terms “Complementarity-determining region” or “CDR” refer to short polypeptide sequences within the variable region of both heavy and light chain polypeptides that are primarily responsible for mediating specific antigen recognition. The term “framework region” refers to amino acid sequences within the variable region of both heavy and light chain polypeptides that are not CDR sequences, and are primarily responsible for maintaining correct positioning of the CDR sequences to permit antigen binding. Although the framework regions themselves typically do not directly participate in antigen binding, as is known in the art, certain residues within the framework regions of certain antibodies can directly participate in antigen binding or can affect the ability of one or more amino acids in CDRs to interact with antigen.

[0142] Examples of antibodies are anti PCSK-9 mAb (e.g., Alirocumab), anti IL-6 mAb (e.g., Sarilumab), and anti IL-4 mAb (e.g., Dupilumab).

[0143] Pharmaceutically acceptable salts of any API described herein are also contemplated for use in a drug or medicament in a drug delivery device. Pharmaceutically acceptable salts are for example acid addition salts and basic salts.

[0144] Those of skill in the art will understand that modifications (additions and / or removals) of various components of the APIs, formulations, apparatuses, methods, systems and embodiments described herein may be made without departing from the full scope and spirit of the present invention, which encompass such modifications and any and all equivalents thereof.

[0145] An example drug delivery device may involve a needle-based injection system as described in Table 1 of section 5.2 of ISO 11608-1 :2014(E). As described in ISO 11608-1 :2014(E), needlebased injection systems may be broadly distinguished into multi-dose container systems and single-dose (with partial or full evacuation) container systems. The container may be a replaceable container or an integrated non-replaceable container. As further described in ISO 11608-1 :2014(E), a multi-dose container system may involve a needle-based injection device with a replaceable container. In such a system, each container holds multiple doses, the size of which may be fixed or variable (pre-set by the user). Another multi-dose container system may involve a needle-based injection device with an integrated non-replaceable container. In such a system, each container holds multiple doses, the size of which may be fixed or variable (pre-set by the user).

[0146] As further described in ISO 11608-1 :2014(E), a single-dose container system may involve a needle-based injection device with a replaceable container. In one example for such a system, each container holds a single dose, whereby the entire deliverable volume is expelled (full evacuation). In a further example, each container holds a single dose, whereby a portion of the deliverable volume is expelled (partial evacuation). As also described in ISO 11608-1 :2014(E), a single-dose container system may involve a needle-based injection device with an integrated non-replaceable container. In one example for such a system, each container holds a single dose, whereby the entire deliverable volume is expelled (full evacuation). In a further example, each container holds a single dose, whereby a portion of the deliverable volume is expelled (partial evacuation).

[0147] Those of skill in the art will understand that modifications (additions and / or removals) of various components of the substances, formulations, apparatuses, methods, systems and embodiments described herein may be made without departing from the full scope and spirit of the present invention, which encompass such modifications and any and all equivalents thereof.

[0148] LIST OF REFERENCE NUMERALS

[0149] 10 Drug Delivery Device 102 Syringe Sub-Assembly

[0150] 11 Housing 103 Cap Sub-Assembly

[0151] 12 Cap 40 111 Housing

[0152] 13 Needle Sleeve 112 Empty Internal Volume 17 Needle 113 End Cap

[0153] 20 Distal Region 114 Guide

[0154] 21 Proximal Region 115 First Wall

[0155] 22 Button 45 116 Second Wall

[0156] 23 Bung / Piston 117 Gap

[0157] 118 First Recess

[0158] 100 Medicament Delivery System 119 Second Recess

[0159] 101 Drive Sub-Assembly 120 Ramped Surface 121 Piston Rod 162 Central Aperture

[0160] 122 Piston Rod Biasing Member 163 Distal Face Gear

[0161] 124 Main Body 164 Plurality of Teeth

[0162] 125 Thread 30 165 Ramped Surface

[0163] 127 Projection 167 Annular Wall

[0164] 129 Internal Bore 168 Cut-Out Section

[0165] 131 Clutch Mechanism 169 Locking Element

[0166] 132 Clutch Housing 171 Central Aperture

[0167] 133 Clutch Body 35 172 Thread

[0168] 134 Nut 174 Proximal Face Gear

[0169] 141 Distal Ratchet Mechanism 175 Plurality of Teeth

[0170] 142 First Ratchet 181 Internal Thread

[0171] 143 First Pawl

[0172] 145 Proximal Ratchet Mechanism 40 201 Pre-Filled Syringe Carrier Body

[0173] 146 Second Ratchet 202 Pre-Filled Syringe

[0174] 147 Second Pawl 203 Syringe

[0175] 151 Tubular Section 206 Needle Cover

[0176] 152 Central Aperture 207 Needle Cover Biasing Member

[0177] 153 Arm 45 208 Cover Portion

[0178] 154 Annular Wall 209 Arm Portion

[0179] 155 Cut-Out Section 211 Pair of Needle Levers

[0180] 156 Clip 215 External Thread

[0181] 157 Stalk Portion 221 Cap

[0182] 158 Barb Portion 50 222 Needle Shield

[0183] 159 Rib

[0184] 161 Annular Plate 301 Cassette

Claims

CLAIMS1. A reusable drive sub-assembly (101) for a medicament delivery system (100) configured to be removably rotationally attachable to a syringe sub-assembly (102) between an attached configuration and a detached configuration, the reusable drive sub-assembly comprising: a housing (111), a piston rod (121) configured to be moved between a proximal position and a distal position; a piston rod biasing member (122) configured to bias the piston rod into the distal position; and a clutch mechanism (131) located in the housing and releasably rotationally lockable to the piston rod; wherein the clutch mechanism is engageable by a mating portion of a removable syringe sub-assembly when a removable syringe sub-assembly is rotationally attached to the reusable drive sub-assembly; wherein the clutch mechanism is configured to move the piston rod from its distal position to its proximal position when a removable syringe sub-assembly and the reusable drive sub-assembly are moved from their attached configuration to their detached configuration.

2. The reusable drive sub-assembly (101)according to claim 1 , wherein the clutch mechanism (131) comprises a clutch housing (132) that is fixed longitudinally with respect to the housing (111), a clutch body (133) that is rotationally locked to the clutch housing, and a nut (134) that is longitudinally locked relative to the clutch housing.

3. The reusable drive sub-assembly (101) according to claim 2, wherein the clutch housing (132) comprises one part (142, 143) of a distal ratchet mechanism (141) configured to engage with another part (142, 143) of the distal ratchet mechanism on the mating portion of the removable syringe sub-assembly (102) when the reusable drive sub-assembly and the removable syringe sub-assembly are rotationally attached, wherein the distal ratchet mechanism is configured to prevent relative rotational movement between the clutch housing and the removable syringe sub-assembly during movement from the attached configuration to the detached configuration and allow relative rotational movement between the clutch housing and the removable syringe sub-assembly during movement from the detached configuration to the attached configuration.

4. The reusable drive sub-assembly (101) according to claim 2 or claim 3, further comprising a proximal ratchet mechanism (145), wherein one part (146, 147) of the proximal ratchet mechanism is formed on the clutch housing (132) and another part (119, 146, 147) of the proximal ratchet mechanism is formed on the housing (111), wherein the proximal ratchet mechanism is configured to prevent relative rotational motion of the clutch housing to the reusable drive sub-assembly in the opposing direction to the rotational movement of the removable syringe sub assembly from the attached configuration to the detached configuration5. The reusable drive sub-assembly (101) according to any one of claim 2 to claim 4, wherein the clutch body (133) is moveable between a proximal position in which the clutch body is disengaged from the nut (134) and a distal position in which the clutch body is engaged with the nut.

6. The reusable drive sub-assembly (101) according to claim 5, wherein the clutch body (133) comprises a distal face gear (163) configured to mate with a proximal face gear (174) of the nut (134) when the clutch body is in the distal position to prevent rotation of the nut relative to the clutch housing (132).

7. The reusable drive sub-assembly (101) according to claim 5 or claim 6, wherein the clutch body (133) comprises at least one ramped surface (165) on a proximally facing surface configured to engage with at least one ramped surface (120) on the housing (111), wherein the ramped surfaces are configured to move the clutch body from its disengaged position to its engaged position upon rotation of the reusable drive sub-assembly and the removable syringe sub-assembly (102) from their attached configuration.

8. The reusable drive sub-assembly (101) according to any one of claim 5 to claim 7, wherein the nut (134) is configured to move the piston rod (121) from the distal position to the proximal position when the reusable drive sub-assembly and the removable syringe subassembly (102) are moved from their attached configuration to their detached configuration.

9. The reusable drive sub-assembly (101) according to claim 8, wherein the nut (134) comprises a threaded central aperture (171) configured to threadingly engage with a thread (125) on the piston rod (121) such that rotation of the nut by rotation of the reusable drive subassembly and the removable syringe sub-assembly (102) from their attached configuration to their detached configuration causes proximal translation of the piston rod.

10. A medicament delivery device system (100) comprisinga reusable drive sub-assembly (101) according to any one of the preceding claims, and a removably attachable syringe sub-assembly (102) comprising a mating portion configured to engage the clutch mechanism (131) when the removable attachable syringe subassembly is rotationally attached to the reusable drive sub-assembly.11 . The medicament delivery system (100) according to claim 10, wherein the removable syringe sub-assembly (102) comprises a needle and a needle cover (206) that is movable between an extended position, in which the needle is covered by the needle cover, and a retracted position, in which the needle is exposed, wherein the needle cover is configured to move the clutch body (133) into the proximal position when the needle cover is in its retracted position.

12. The medicament delivery system (100) according to claim 10 or claim 11 , wherein the removable syringe sub-assembly (102) comprises a syringe carrier body (201) configured to receive a disposable syringe (203).

13. The medicament delivery system (100) according to claim 10 to claim 11 , wherein the removable syringe sub-assembly (102) comprises a disposable cassette (301) comprising a syringe.

14. The medicament delivery system (100) according to any one of claim 10 to claim 13, wherein the removable syringe sub-assembly (102) comprises a medicament.

15. A method of recharging a reusable drive sub-assembly (101) for a medicament delivery system (100) for reuse, the method comprising the steps of: rotating a reusable drive sub-assembly (101) and a removable syringe sub-assembly (102) relative to each other from an attached configuration to a detached configuration; engaging a clutch mechanism (131) to rotationally lock to a piston rod (121); and transforming relative rotational motion of the reusable drive sub-assembly (101) and the removable syringe sub-assembly (102) via the clutch mechanism (131) to translational motion of the piston rod (121); and moving the piston rod (121) from a distal position to a proximal position.

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