Patent Publication Number: US-2023158250-A1

Title: Drug delivery device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/758,781, filed Apr. 23, 2020, which is the national stage entry of International Patent Application No. PCT/EP2018/079918, filed on Nov. 1, 2018, and claims priority to Application No. EP 17306523.6, filed on Nov. 3, 2017, the disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure generally relates to a drug delivery device having a plunger release mechanism. 
     BACKGROUND 
     Drug delivery devices (i.e. devices capable of delivering medicaments from a medication container) typically fall into two categories—manual devices and auto-injectors. 
     In a manual device—the user must provide the mechanical energy to drive the fluid through the needle. This is typically done by some form of button/plunger that has to be continuously pressed by the user during the injection. There are numerous disadvantages to the user from this approach. If the user stops pressing the button/plunger then the injection will also stop. This means that the user can deliver an underdose if the device is not used properly (i.e. the plunger is not fully pressed to its end position). Injection forces may be too high for the user, in particular if the patient is elderly or has dexterity problems. 
     Auto-injectors are devices which completely or partially replace activities involved in parenteral drug delivery from standard syringes. These activities may include removal of a protective syringe cap, insertion of a needle into a patient&#39;s skin, injection of the medicament, removal of the needle, shielding of the needle and preventing reuse of the device. This overcomes many of the disadvantages of manual devices. Injection forces/button extension, hand-shaking and the likelihood of delivering an incomplete dose are reduced. Triggering may be performed by numerous means, for example a trigger button or the action of the needle reaching its injection depth. In some devices the energy to deliver the fluid is provided by a spring. 
     Plunger release mechanisms are applied to control motion of a plunger in a drug delivery device in a manner keeping the plunger in a defined position until a condition is met suddenly allowing the plunger to move within the drug delivery device thus delivering a dose of a drug from a syringe. 
     SUMMARY 
     The present disclosure provides a drug delivery device with an improved plunger release mechanism as well as a method for assembling a drug delivery device. 
     According to the present disclosure, a drug delivery device comprises a housing adapted to receive a medicament container, a plunger and a plunger release mechanism comprising: a first plunger boss arranged on the plunger, a profiled slot arranged on the housing and adapted to be engaged by the first plunger boss so as to inhibit movement of the plunger in a distal direction, wherein the plunger is rotatable about a longitudinal axis to release the first plunger boss from the profiled slot so as to allow movement of the plunger in the distal direction, a sleeve coupled to the housing to permit movement of the sleeve relative to the housing, wherein a sleeve ramp is arranged on the sleeve, the sleeve ramp adapted to engage a projection such as a rib or boss on the plunger to rotate the plunger to release the first plunger boss from the profiled slot when the sleeve is moved in a proximal direction. 
     In an exemplary embodiment, the profiled slot is adapted to induce a torque to the plunger when an axial force is applied to the plunger, wherein the profiled slot comprises at least one angled surface adapted to engage the first plunger boss to induce a torque in a first rotational direction to the plunger to release the first plunger boss from the profiled slot. 
     In an exemplary embodiment, the profiled slot further comprises a wall for limiting movement of the first plunger boss in the first rotational direction when engaged to the first angled surface and a second angled surface adjacent the wall and adapted to induce a torque in the first rotational direction to the plunger to release the first plunger boss from the profiled slot. 
     This allows for preventing the plunger from being released while the first plunger boss is engaged to the first angled surface and the wall. This state is particularly useful for storing and transporting a drug delivery device or a part thereof comprising the plunger and optionally a drive spring so that the drive spring cannot inadvertently advance the plunger, e.g. if the drug delivery device or the part thereof comprising the plunger is dropped. In order to transition the plunger into a state in which it may be released, the plunger may be moved away from the first angled surface along the wall and rotated so that the first plunger boss engages the second angled surface. The transition into this state may be performed during final assembly of a drug delivery device. If the plunger is not otherwise prevented from rotating further, the first plunger boss may slide down the second angled surface until disengaging it, allowing the plunger to advance, e.g. for displacing a medicament from a medicament container, in particular a syringe. In an exemplary embodiment, the plunger may be prevented from rotating further by a sleeve rib on a sleeve which may be moved on contact with an injection site to allow further rotation of the plunger. 
     In an exemplary embodiment, the drug delivery device may comprise the above described profiled slot with the first and second angled surfaces and the wall without having a sleeve ramp adapted to engage a projection such as a rib or boss on the plunger. 
     In an exemplary embodiment, the first angled surface and/or the second angled surface have/has an angle in a range from 30° to 70° relative to a perpendicular on a longitudinal axis of the plunger. 
     In an exemplary embodiment, the plunger release mechanism further comprises a second plunger boss arranged on the plunger and a sleeve rib arranged on the sleeve, the sleeve rib having a longitudinal face adapted to engage the second plunger boss preventing rotation of the plunger in the first rotational direction to keep the first plunger boss engaged to the angled surface, wherein the sleeve rib is adapted to disengage the second plunger boss when the sleeve rib is moved in a proximal direction thereby allowing the plunger to rotate in the first rotational direction and the first plunger boss to disengage the second angled surface. 
     In an exemplary embodiment, the plunger release mechanism further comprises an angled plunger rib on the plunger adapted to abut the sleeve rib so as to induce a torque to the plunger in the first rotational direction and push the plunger in the proximal direction when the first plunger boss is engaged to the first angled surface and to the wall. 
     In an exemplary embodiment, the sleeve rib comprises a distal face adapted to engage the second plunger boss so as to limit movement of the sleeve rib in a distal direction relative to the plunger. 
     In an exemplary embodiment, the release of the first plunger boss from the first angled surface and/or from the second angled surface and/or the release of the second plunger boss from the sleeve rib provides an audible feedback. 
     The sleeve may be adapted to be moved in a proximal direction relative to the housing upon contact with an injection site to disengage the sleeve rib from the second plunger boss. 
     In an exemplary embodiment, a drive spring is arranged within the housing and adapted to bias the plunger in the distal direction for displacing a piston of a medicament container. 
     In an exemplary embodiment, the plunger is hollow and the drive spring is arranged within the plunger. 
     In an exemplary embodiment, the housing comprises a distal region and a proximal region, wherein the proximal region comprises the profiled slot. 
     In an exemplary embodiment, the angled plunger rib is adapted to abut the sleeve rib upon coupling of the proximal region with the plunger and the drive spring to the distal region for moving the first plunger boss from the first angled surface to the second angled surface. 
     In an exemplary embodiment, the drug delivery device comprises a medicament container. 
     In an exemplary embodiment, the medicament container contains a medicament. 
     According to an aspect of the present disclosure, a method for assembling a drug delivery device, comprises providing a plunger having a first plunger boss and an angled plunger rib, providing a housing having a profiled slot comprising a first angled surface adapted to engage the first plunger boss to induce a torque in a first rotational direction to the plunger, a wall for limiting movement of the first plunger boss in the first rotational direction when engaged to the first angled surface and a second angled surface adapted to induce a torque in the first rotational direction to the plunger, providing a sleeve having a sleeve rib, inserting the plunger and a drive spring into the housing, rotating the plunger by an angle in a second rotational direction to engage the first plunger boss to the first angled surface and the wall, moving the sleeve in a proximal direction so that the sleeve rib proximally abuts the angled plunger rib thereby inducing a torque to the plunger in the first rotational direction and pushing the plunger in the proximal direction so that the first plunger boss disengages from the wall and engages the second angled surface. 
     The drug delivery device, as described herein, may be configured to inject a drug or 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&#39;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 5 ml). 
     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 3 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. 
     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. 
     The one or more automated functions of an auto-injector may 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 may be a one-step or multi-step process. That is, a user may need to activate one or more activation mechanism in order to cause the automated function. For example, a user may depress a needle sleeve against their body in order to cause injection of a medicament. In other devices, a user may be required to depress a button and retract a needle shield in order to cause injection. 
     In addition, such activation may activate one or more mechanisms. For example, an activation sequence 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 sequence independent steps. 
     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). 
     Further scope of applicability of the present disclosure will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The present disclosure will become more fully understood from the detailed description given below and the accompanying drawings, which are given by way of illustration only, and do not limit the present disclosure, and wherein: 
         FIGS.  1 A and  1 B  are schematic views of an exemplary embodiment of a drug delivery device, 
         FIG.  2    is a schematic perspective exploded view of a drive subassembly of a drug delivery device, 
         FIG.  3    is a schematic side view of the drive subassembly, 
         FIGS.  4 A and  4 B  are schematic detail views of the drive subassembly showing a plunger release mechanism, 
         FIG.  5    is a schematic view of an exemplary embodiment of the plunger release mechanism during assembly of the drive subassembly, 
         FIG.  6    is a schematic view of the plunger release mechanism during final assembly, 
         FIG.  7    is a schematic view of the plunger release mechanism after final assembly, 
         FIG.  8    is a schematic view of the plunger release mechanism after depression of a sleeve, 
         FIG.  9    is a schematic detail view of the plunger release mechanism after final assembly and prior to depression of the sleeve, 
         FIG.  10    is a schematic detail view of the plunger release mechanism during depression of the sleeve, and 
         FIG.  11    is a schematic detail view of another embodiment of the plunger release mechanism during depression of the sleeve. 
     
    
    
     Corresponding parts are marked with the same reference symbols in all figures. 
     DETAILED DESCRIPTION 
     According to some embodiments of the present disclosure, an exemplary drug delivery device  10  is shown in  FIGS.  1 A and  1 B . Device  10 , as described above, is configured to inject a drug or medicament into a patient&#39;s body. 
     Device  10  includes a housing  11  which typically contains a reservoir containing the medicament to be injected (e.g., a syringe  24  or a container) 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 , in particular on a distal or front end D of the device  10 . Typically, a user must remove cap assembly or cap  12  from housing  11  before device  10  can be operated. 
     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. 
     Device  10  can also include a needle sleeve  13  coupled to the housing  11  to permit movement of the sleeve  13  relative to the housing  11 . For example, the sleeve  13  can move in a longitudinal direction parallel to longitudinal axis X. Specifically, movement of the sleeve  13  in a proximal direction can permit a needle  17  to extend from distal region  20  of housing  11 . 
     Insertion of the needle  17  can occur via several mechanisms. For example, the needle  17  may be fixedly located relative to housing  11  and initially be located within an extended needle sleeve  13 . Proximal movement of the sleeve  13  by placing a distal end of sleeve  13  against a patient&#39;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&#39;s body. Such insertion is termed “manual” insertion as the needle  17  is manually inserted via the patient&#39;s manual movement of the housing  11  relative to the sleeve  13 . 
     Another form of insertion is “automated,” whereby the 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.  1 A &amp;  1 B , button  22  is located at a proximal or back end P of the housing  11 . However, in other embodiments, button  22  could be located on a side of housing  11 . In further embodiments, the button  22  has been deleted and is replaced for instance by a sleeve trigger mechanism, e.g. provided by pushing the needle sleeve  13  inside the housing when the drug delivery device is put onto an injection side. 
     Other manual or automated features can include drug injection or needle retraction, or both. Injection is the process by which a bung or piston  23  is moved from a proximal location within a container or syringe  24  to a more distal location within the syringe  24  in order to force a medicament from the syringe  24  through needle  17 . 
     In some embodiments, an energy source, e.g. a drive spring  30  is arranged in a plunger  40  and is under compression before device  10  is activated. A proximal end of the drive spring  30  can be fixed within proximal region  21  of housing  11 , and a distal end of the drive spring  30  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  30  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  24 , forcing it out of needle  17 . 
     Following injection, the 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&#39;s body. This can occur as needle  17  remains fixedly located relative to housing  11 . Once a distal end of the sleeve  13  has moved past a distal end of the needle  17 , and the needle  17  is covered, the sleeve  13  can be locked. Such locking can include locking any proximal movement of the sleeve  13  relative to the housing  11 . 
     Another form of needle retraction can occur if the needle  17  is moved relative to the housing  11 . Such movement can occur if the syringe within the housing  11  is moved in a proximal direction relative to the housing  11 . This proximal movement can be achieved by using a retraction spring (not shown), located in the distal region  20 . A compressed retraction spring, when activated, can supply sufficient force to the syringe  24  to move it in a proximal direction. Following sufficient retraction, any relative movement between the needle  17  and the housing  11  can be locked with a locking mechanism. In addition, button  22  or other components of device  10  can be locked as required. 
     In some embodiments, the housing may comprise a window  11   a  through which the syringe  24  can be monitored. 
     The drug delivery device  10  may be divided in two subassemblies, a control subassembly and a drive subassembly  10 . 1 . This allows for improving flexibility as to the time and location of manufacture of the subassemblies and final assembly with the syringe  24 . 
       FIG.  2    is a perspective exploded view of the drive subassembly  10 . 1 . The drive subassembly  10 . 1  comprises components used to displace the medicament from the syringe  24 . If the viscosity or volume of the medicament M in the syringe  24  is varied, only parts of the drive subassembly  10 . 1  may need to be changed. The drive subassembly  10 . 1  comprises the plunger  40 , the drive spring  30  and the proximal region  21  of the housing  11 . In an exemplary embodiment, the drive subassembly  10 . 1  may be assembled in a process which requires virtually only axial motion except for the plunger  40 . In order to assemble the drive subassembly  10 . 1  the drive spring  30  is inserted into the plunger  40  and the plunger  40  is inserted in the proximal region  21  in the proximal direction P thereby compressing the drive spring  30 . Once the plunger  40  reaches a compressed position it is rotated by an angle, e.g. approximately 30° to lock it to the proximal region  21 . In an exemplary embodiment the proximal region  21  could have a cam surface which could induce this rotation prior to the plunger  40  reaching the compressed position. 
     Furthermore, a feedback element  50 , e.g. a spring element may be provided to indicate an event, e.g. an end of dose, by providing an audible and/or tactile feedback. 
       FIG.  3    is a schematic side view of the drive subassembly  10 . 1 .  FIGS.  4 A and  4 B  are schematic detail views of the drive subassembly  10 . 1  showing part of a plunger release mechanism  25 . 
     The plunger release mechanism  25  controls the activation of syringe emptying. The plunger release mechanism  25  is adapted to release the plunger  40  once the sleeve  13  is depressed and reaches a retracted position RP within the housing  11 . 
     The plunger release mechanism  25  comprises a first plunger boss  40 . 1  arranged on the plunger  40  and a profiled slot  21 . 1  in the proximal region  21  of the housing  11 . The profiled slot  21 . 1  comprises a first angled surface  21 . 2  adapted to engage the first plunger boss  40 . 1  to induce a torque in a first rotational direction R 1  to the plunger  40 , a wall  21 . 3  for limiting movement of the first plunger boss  40 . 1  in the first rotational direction R 1  when engaged to the first angled surface  21 . 2 . Furthermore, the profiled slot  21 . 1  comprises a second angled surface  21 . 4  adapted to engage the first plunger boss  40 . 1  to induce a torque in the first rotational direction R 1  to the plunger  40 . 
     The first angled surface  21 . 2  and/or the second angled surface  21 . 4  may have an angle in a range from 30° to 70° relative to a perpendicular on the longitudinal axis X of the drug delivery device  10  which may also be the longitudinal axis of the plunger  40 . 
     In a first state shown in  FIG.  4 A , the first plunger boss  40 . 1  is engaged to the first angled surface  21 . 2 . Due to the drive spring  30  acting on the plunger  40 , the first plunger boss  40 . 1  is pressed against the first angled surface  21 . 2  in a distal direction D such that a torque is induced to the plunger  40  in the first rotational direction R 1  so that the first plunger boss  40 . 1  slides along the first angled surface  21 . 2  until it abuts the wall  21 . 3  so that rotation of the plunger  40  in the first rotational direction R 1  is halted. 
       FIG.  4 B  shows the plunger release mechanism  25  in a second state. Starting from the first state, the plunger  40  has been moved a distance at least as long as the wall  21 . 3  in the proximal direction P such that the wall  21 . 3  no longer limits movement of the first plunger boss  40 . 1  in the first rotational direction R 1 . The plunger  40  has then been rotated further in the first rotational direction R 1  so that the first plunger boss  40 . 1  engages the second angled surface  21 . 4 . Due to the drive spring  30  acting on the plunger  40 , the first plunger boss  40 . 1  is pressed against the second angled surface  21 . 4  in a distal direction D such that a torque is induced to the plunger  40  in the first rotational direction R 1  so that the first plunger boss  40 . 1  slides along the second angled surface  21 . 4 . If the plunger  40  is not otherwise prevented from rotating further, the first plunger boss  40 . 1  may slide down the second angled surface  21 . 4  until disengaging it, allowing the plunger  40  to advance in the distal direction D to displace the medicament from the syringe  24 . 
     In an exemplary embodiment, movement of the plunger  40  from the first state in the proximal direction P and onto the second angled surface  21 . 4  may be achieved by the sleeve  13  interacting with the plunger  40 , e.g. by engaging the first plunger boss  40 . 1  or a further plunger boss or rib on the plunger (not shown). 
     An exemplary embodiment of the plunger release mechanism  25  is shown in more detail in  FIGS.  5 ,  6 ,  7  and  8   . 
       FIG.  5    shows the plunger release mechanism during assembly of the drive subassembly  10 . 1 . 
     The plunger release mechanism  25  is adapted to release the plunger  40  once the sleeve  13  is depressed and reaches a retracted position within the housing  11 . 
     The plunger release mechanism  25  comprises the plunger  40 , the proximal region  21 , and the sleeve  13  interacting with each other. The sleeve  13  and the proximal region  21  are configured to move only in parallel with the longitudinal axis X relative to each other whereas the plunger  40  can move both in parallel with the longitudinal axis X and rotate about the longitudinal axis X. The parts of the plunger release mechanism  25  may be essentially rigid and require no deformation in order to function correctly. 
     The parts arranged for engaging the plunger  40 , proximal region  21  and sleeve  13  comprise: a first plunger boss  40 . 1  on the plunger  40 , a second plunger boss  40 . 2  on the plunger  40 , an angled plunger rib  40 . 3  on the plunger  40 , a profiled slot  21 . 1  in the proximal region  21  adapted to interact with the first plunger boss  40 . 1 , a sleeve rib  13 . 1  on the sleeve  13  comprising a proximal face  13 . 2  adapted to interact with the angled plunger rib  40 . 3 , a distal face  13 . 3  and a longitudinal face  13 . 4  adapted to interact with the second plunger boss  40 . 2 . 
     The profiled slot  21 . 1  comprises a first angled surface  21 . 2  adapted to engage the first plunger boss  40 . 1  to induce a torque in a first rotational direction R 1  to the plunger  40 , a wall  21 . 3  for limiting movement of the first plunger boss  40 . 1  in the first rotational direction R 1  when engaged to the first angled surface  21 . 2 . Furthermore, the profiled slot  21 . 1  comprises a second angled surface  21 . 4  adapted to engage the first plunger boss  40 . 1  to induce a torque in the first rotational direction R 1  to the plunger  40 . 
     During assembly of the drive subassembly  10 . 1  the plunger  40  with the drive spring  30  is inserted into the proximal region  21 . Once the plunger  40  reaches a proximal position the first plunger boss  40 . 1  is axially aligned with the profiled slot  21 . 1 . By rotating the plunger  40  in a second rotational direction R 2  by an angle, e.g. approximately 30°, the first plunger boss  40 . 1  is moved into the profiled slot  21 . 1 . In this position the first angled surface  21 . 2  moves the first plunger boss  40 . 1  against the wall  21 . 3  by inducing a torque to the plunger  40  in the first rotational direction R 1  due to the drive spring  30  biasing the plunger  40  in the distal direction D. 
     In order to assemble the drug delivery device  10 , a syringe  24  may be inserted into the control subassembly which may comprise the distal region  20  of the housing  11 . 
     Afterwards, the drive subassembly  10 . 1  is inserted into the control subassembly in the distal direction D. The proximal region  21  and the distal region  20  may comprise snap connections to lock them together when assembled. During the final assembly of the drug delivery device  10  the sleeve  13  may be partially depressed to allow initiation of the plunger release mechanism  25 , e.g. by an assembly jig (not illustrated) or in a different way. 
       FIG.  6    shows the plunger release mechanism  25  during the final assembly. The sleeve rib  13 . 1  proximally abuts the angled plunger rib  40 . 3  thereby inducing a torque to the plunger  40  in the first rotational direction R 1  and pushing the plunger  40  in the proximal direction P so that the first plunger boss  40 . 1  moves along the wall  21 . 3  until it disengages from the wall  21 . 3 . Due to the induced torque, the first plunger boss  40 . 1  moves in the first rotational direction R 1  and engages the second angled surface  21 . 4 . The depression of the sleeve  13  may cease and, due to the first plunger boss  40 . 1  engaging the second angled surface  21 . 4  and the drive spring  30  acting on the plunger  40  in the distal direction D, the plunger  40  rotates further in the first rotational direction R 1 . As the sleeve  13  is not being depressed further it may move in the distal direction D relative to the housing  11 , e.g. under the action of a sleeve spring (not illustrated). This movement is limited by the second plunger boss  40 . 2  abutting the distal face  13 . 3  on the sleeve rib  13 . 1 . Further rotation of the plunger  40  in the first rotational direction R 1  is prevented by the second plunger boss  40 . 2  abutting the longitudinal face  13 . 4  of the sleeve rib  13 . 1 . The load of the drive spring  30  is resolved within the proximal region  21  by the first plunger boss  40 . 1  engaging the profiled slot  21 . 1 . This state of the plunger release mechanism  25  is illustrated in  FIG.  7   . 
     A sequence of operation of the drug delivery device  10  may be as follows: 
     The user removes the cap assembly  12  pulling it in the distal direction D away from the housing  11 . Removal of the cap assembly  12  may at the same time remove a protective needle sheath from the needle  17 . 
     The sleeve  13  is in an extended position protruding from the housing  11  in the distal direction D. The extended position may be defined by the second plunger boss  40 . 2  proximally abutting the distal face  13 . 3  of the sleeve rib  13 . 1 . 
     The user may then press the drug delivery device  10  with the sleeve  13  ahead against an injection site, e.g. a patient&#39;s skin thereby moving the sleeve  13  from the extended position towards a retracted position against the bias of the shroud spring. 
       FIG.  8    is a schematic view of the plunger release mechanism  25  after depression of the sleeve  13  into the retracted position. As the sleeve  13  is being moved from the extended position towards the retracted position the second plunger boss  40 . 2  moves (starting from the position shown in  FIG.  7   ) relative to the sleeve  13  in the distal direction D guided along the longitudinal face  13 . 4  of the sleeve rib  13 . 1 . 
     In an exemplary embodiment the longitudinal face  13 . 4  of the sleeve rib  13 . 1  may comprise an interruption or bump feature (not illustrated) for creating an increase in the force required to depress the sleeve  13  further. This may be used to indicate to the user that needle insertion would commence with further depression of the sleeve  13 . Up until this point, the user is free to remove the drug delivery device  10  from the injection site and reposition as the sleeve  13  will re-extend to its initial position under the force of the shroud spring. 
     If the user continues pressing the drug delivery device  10  against the injection site the sleeve  13  is moved into the retracted position exposing the needle  17  and inserting it into the injection site. 
     Once the sleeve  13  is depressed into the retracted position, and the needle  17  inserted, the second plunger boss  40 . 2  has moved distally beyond the sleeve rib  13 . 1  such that the plunger  40  is no longer prevented from rotating in the first rotational direction R 1  due to the torque induced by the drive spring  30  and the first plunger boss  40 . 1  engaging the second angled surface  21 . 4  on the profiled slot  21 . 1 . The plunger  40  rotates in the first rotational direction R 1  due to this torque and the first plunger boss  40 . 1  comes clear of the profiled slot  21 . 1 . The plunger  40  is thus released and advances the piston  23  in the distal direction D displacing the medicament from the syringe  24  through the needle  17 . The release of the first or second plunger boss  40 . 1 ,  40 . 2  may provide audible feedback that delivery of the medicament has started. 
       FIG.  9    is a schematic detail view of the plunger release mechanism  25  after final assembly and prior to depression of the sleeve  13 . Movement of the sleeve  13  in the distal direction D relative to the housing  11  is limited by the second plunger boss  40 . 2  abutting the distal face  13 . 3  on the sleeve rib  13 . 1 . Further rotation of the plunger  40  in the first rotational direction R 1  is prevented by the second plunger boss  40 . 2  abutting the longitudinal face  13 . 4  of the sleeve rib  13 . 1 . 
       FIG.  10    is a schematic detail view of the plunger release mechanism  25  during depression of the sleeve  13 . As the sleeve  13  is being moved from the extended position towards the retracted position in the proximal direction P the second plunger boss  40 . 2  moves (starting from the position shown in  FIG.  9   ) relative to the sleeve  13  in the distal direction D guided along the longitudinal face  13 . 4  of the sleeve rib  13 . 1 . 
     If the user continues pressing the drug delivery device  10  against the injection site the sleeve  13  is moved into the retracted position exposing the needle  17  and inserting it into the injection site. 
     Once the sleeve  13  is depressed into the retracted position, and the needle  17  inserted, the second plunger boss  40 . 2  has moved distally beyond the sleeve rib  13 . 1  such that the plunger  40  is no longer prevented from rotating in the first rotational direction R 1  due to the torque induced by the drive spring  30  and the first plunger boss  40 . 1  engaging the second angled surface  21 . 4  on the profiled slot  21 . 1 . The plunger  40  rotates in the first rotational direction R 1  due to this torque and the first plunger boss  40 . 1  comes clear of the profiled slot  21 . 1 . The plunger  40  is thus released and advances the piston  23  in the distal direction D displacing the medicament from the syringe  24  through the needle  17 . 
       FIG.  11    is a schematic detail view of another embodiment of the plunger release mechanism  25  during depression of the sleeve  13 . In addition to the embodiment described above, a sleeve ramp  13 . 5  is provided on the sleeve  13 . As the sleeve  13  approaches the retracted position, the sleeve ramp  13 . 5  engages a projection such as a rib or boss on the plunger  40 , e.g. the angled plunger rib  40 . 3  to actively rotate the plunger  40  in the first rotational direction R 1 . If the plunger  40  should not rotate spontaneously due to the features of the previous embodiments, the additional sleeve ramp  13 . 5  will induce rotation of the plunger  40 . 
     During normal use, the plunger  40  will release as in the previous embodiments. The sleeve ramp  13 . 5  is positioned to only interact with the angled plunger rib  40 . 3  if the plunger  40  has not spontaneously rotated near the end of the depression of the sleeve  13 . The skilled person will readily understand that the embodiment of  FIG.  11    would likewise work if only one of the rib or boss on the plunger  40 , e.g. the angled plunger rib  40 . 3 , or the sleeve ramp  13 . 5  was ramped or angled. 
     Another benefit of the embodiment of  FIG.  11    is that it provides additional guidance of the plunger  40  movement as it activates. 
     In another exemplary embodiment, the sleeve ramp  13 . 5  engaging the rib or boss on the plunger  40 , e.g. the angled plunger rib  40 . 3 , may be the only way to rotate the plunger  40  out of engagement with the profiled slot  21 . 1 . For example, the profiled slot  21 . 1  may not have an angled surface causing the plunger  40  to rotate in the first rotational direction R 1  out of engagement with the profiled slot  21 . 1 . In an exemplary embodiment, the profiled slot  21 . 1  may only have a transversal surface towards the distal direction D and transversally oriented relative to the longitudinal axis X. The transversal surface may have a detent or bump. In another exemplary embodiment the profiled slot  21 . 1  may only have an angled surface causing the plunger to rotate in the second rotational direction R 2  maintaining the first plunger boss  40 . 1  engaged within the profiled slot  21 . 1 . 
     In an exemplary embodiment, the drug delivery device  10  may be an auto-injector. 
     The terms “drug” or “medicament” are used herein to describe one or more pharmaceutically active compounds. As described below, a drug or medicament can include at least one small or large molecule, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Exemplary pharmaceutically active compounds may include small molecules; 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 of these drugs are also contemplated. 
     The term “drug delivery device” shall encompass any type of device or system configured to dispense a drug into a human or animal body. Without limitation, a drug delivery device may be an injection device (e.g., syringe, pen injector, auto injector, large-volume device, pump, perfusion system, or other device configured for intraocular, subcutaneous, intramuscular, or intravascular delivery), skin patch (e.g., osmotic, chemical, micro-needle), inhaler (e.g., nasal or pulmonary), implantable (e.g., coated stent, capsule), or feeding systems for the gastro-intestinal tract. The presently described drugs may be particularly useful with injection devices that include a needle, e.g., a small gauge needle. 
     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 vessel configured to provide a suitable chamber for storage (e.g., short- or long-term storage) of one or more pharmaceutically active compounds. 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 dual-chamber cartridge configured to store two or more components of a drug formulation (e.g., a drug and a diluent, or two different types of 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 of the drug or medicament 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. 
     The drug delivery devices and drugs described herein can be used for the treatment and/or prophylaxis of many different types of disorders. Exemplary 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 exemplary disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis. 
     Exemplary drugs for the treatment and/or prophylaxis of diabetes mellitus or complications associated with 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 term “derivative” refers to any substance which is sufficiently structurally similar to the original substance so as to have substantially similar functionality or activity (e.g., therapeutic effectiveness). 
     Exemplary insulin analogues are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin; Lys(B28), Pro(B29) human insulin; Asp(B28) human insulin; human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val 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. 
     Exemplary insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin; 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—(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin. Exemplary GLP-1, GLP-1 analogues and GLP-1 receptor agonists are, for example: Lixisenatide/AVE0010/ZP10/Lyxumia, Exenatide/Exendin-4/Byetta/Bydureon/ITCA 650/AC-2993 (a 39 amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide/Victoza, Semaglutide, Taspoglutide, Syncria/Albiglutide, Dulaglutide, rExendin-4, CJC-1134-PC, PB-1023, TTP-054, Langlenatide/HM-11260C, CM-3, GLP-1 Eligen, ORMD-0901, 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, TT-401, BHM-034. MOD-6030, CAM-2036, DA-15864, ARI-2651, ARI-2255, Exenatide-XTEN and Glucagon-Xten. 
     An exemplary oligonucleotide is, for example: mipomersen/Kynamro, a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia. 
     Exemplary DPP4 inhibitors are Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine. 
     Exemplary 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. 
     Exemplary 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. 
     The term “antibody”, as used herein, refers to an immunoglobulin molecule or an antigen-binding 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 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 disclosure 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, and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), 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. 
     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. 
     Exemplary antibodies are anti PCSK-9 mAb (e.g., Alirocumab), anti IL-6 mAb (e.g., Sarilumab), and anti IL-4 mAb (e.g., Dupilumab). 
     The compounds described herein may be used in pharmaceutical formulations comprising (a) the compound(s) or pharmaceutically acceptable salts thereof, and (b) a pharmaceutically acceptable carrier. The compounds may also be used in pharmaceutical formulations that include one or more other active pharmaceutical ingredients or in pharmaceutical formulations in which the present compound or a pharmaceutically acceptable salt thereof is the only active ingredient. Accordingly, the pharmaceutical formulations of the present disclosure encompass any formulation made by admixing a compound described herein and a pharmaceutically acceptable carrier. 
     Pharmaceutically acceptable salts of any drug described herein are also contemplated for use in drug delivery devices. Pharmaceutically acceptable salts are for example acid addition salts and basic salts. Acid addition salts are e.g. HCl or HBr salts. Basic salts are e.g. salts having a cation selected from an alkali or alkaline earth metal, e.g. Na+, or K+, or Ca2+, or an ammonium ion N+(R1)(R2)(R3)(R4), wherein R1 to R4 independently of each other mean: hydrogen, an optionally substituted C1-C6-alkyl group, an optionally substituted C2-C6-alkenyl group, an optionally substituted C6-C10-aryl group, or an optionally substituted C6-C10-heteroaryl group. Further examples of pharmaceutically acceptable salts are known to those of skill in the arts. 
     Pharmaceutically acceptable solvates are for example hydrates or alkanolates such as methanolates or ethanolates. 
     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 disclosure, which encompass such modifications and any and all equivalents thereof. 
     LIST OF REFERENCES 
     
         
         
           
               10  drug delivery device 
               10 . 1  drive subassembly 
               11  housing 
               11   a  window 
               12  cap assembly 
               13  sleeve 
               13 . 1  sleeve rib 
               13 . 2  proximal face 
               13 . 3  distal face 
               13 . 4  longitudinal face 
               13 . 5  sleeve ramp 
               17  needle 
               20  distal region 
               21  proximal region 
               21 . 1  profiled slot 
               21 . 2  first angled surface 
               21 . 3  wall 
               21 . 4  second angled surface 
               22  button 
               23  piston 
               24  syringe 
               25  plunger release mechanism 
               30  drive spring 
               40  plunger 
               40 . 1  first plunger boss 
               40 . 2  second plunger boss 
               40 . 3  angled plunger rib 
             D distal end, distal direction 
             P proximal end, proximal direction 
             R 1  first rotational direction 
             R 2  second rotational direction 
             X longitudinal axis