Patent Publication Number: US-2021170115-A1

Title: Audible indicator

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 15/578,491, filed on Nov. 30, 2017, which is the national stage entry of International Patent Application No. PCT/EP2016/062454, filed on Jun. 2, 2016, and claims priority to Application No. EP 15170588.6, filed in on Jun. 3, 2015, the disclosures of which are expressly incorporated herein in entirety by reference thereto. 
    
    
     TECHNICAL FIELD 
     The disclosure relates to an audible indicator. 
     BACKGROUND 
     Administering an injection is a process which presents a number of risks and challenges for users and healthcare professionals, both mental and physical. Injection devices typically fall into two categories—manual devices and autoinjectors. In a conventional manual device, manual force is required to drive a medicament through a needle. This is typically done by some form of button/plunger that has to be continuously pressed during the injection. There are numerous disadvantages associated with this approach. For example, if the button/plunger is released prematurely, the injection will stop and may not deliver an intended dose. Furthermore, the force required to push the button/plunger may be too high (e.g., if the user is elderly or a child). And, aligning the injection device, administering the injection, and keeping the injection device still during the injection may require dexterity which some patients (e.g., elderly patients, children, arthritic patients, etc.) may not have. 
     Autoinjector devices aim to make self-injection easier for patients. A conventional autoinjector may provide the force for administering the injection by a spring, and a trigger button or other mechanism may be used to activate the injection. Autoinjectors may be single-use or reusable devices. 
     Furthermore, it is necessary to administer the full dose in order to achieve full effectiveness of the medicament within the patient. 
     Thus, there remains a need for an audible indicator for a drug delivery device. Current indicators may be too quiet or too bulky to use in current autoinjectors and other drug delivery devices. The audible indicators described herein solve one or more of these problems. 
     SUMMARY 
     According to aspects of the current disclosure, there is provided an audible indicator for use with a drug delivery device, the audible indicator comprising a monostable resilient force member configured to reside in either of two states having two different conformations. In a relaxed state, the resilient force member is relaxed in a first conformation. In a biased state, the resilient force member is biased to store energy in a second conformation different to the first conformation. The resilient force member releases stored energy to generate an audible signal when changing from the biased state into the relaxed state due to a transition from the second conformation to the first conformation, wherein the resilient force member is supported by a retaining element in the biased state in order to prevent transition into the relaxed state. 
     As opposed to a bistable spring element, which has to stable states, a monostable spring element may have only one stable state. If resiliently deformed from out of this stable state and subsequently released, the monostable spring element will return to this stable state. In order to keep a monostable spring element in an instable state, an additional component supporting the monostable spring element in the instable state is required. 
     The audible indicator can be used for indicating to a patient or user that the full dose of medicament in the drug delivery device was spent. Thus, the drug delivery device is improved in order to achieve a reliable indication of the end of medicament delivery and a full effectiveness of the medicament within the patient. 
     In an exemplary embodiment, the retaining element is a plunger, wherein the resilient force member is allowed to transition from the biased state by a movement of the plunger that is used to displace the drug from a medicament container. 
     In another exemplary embodiment, the retaining element is adapted to be moved or allowed to move by a plunger or by a drive spring, wherein this movement of the retaining element allows transition of the resilient force member from the biased state. 
     For example, the resilient force member may be allowed to transition from the biased state into the relaxed state when the plunger moves towards or reaches a proximal position at the end of a medicament delivery process. 
     In an exemplary embodiment, the resilient force member includes a leaf spring having a longitudinal axis, wherein the resilient force member is bent by a certain angle about the longitudinal axis forming two angled wing-shaped sections. This enables a priming of the audible indicator with little effort. 
     In an exemplary embodiment, the leaf spring has a rectangular shape, a square shape or an oval shape 
     It is understood that a monostable leaf spring can store energy in the form of tension on one or more outer edges of one or more wing-shaped sections. It is also understood that the monostable leaf spring can also store energy in the form of compression in a central region of one or more wing-shaped sections. 
     For example, the resilient force member is supported when the drug delivery device is in an initial state. Alternatively, the resilient force member is supported when the drug delivery device is in an initial state and in a primed state, wherein a proximal spring section of the resilient force member is supported by a supporting protrusion arranged on a rear case. 
     The resilient force member is configured as a monostable spring element. As opposed to a bistable spring element, a monostable spring element may have only one stable state. In order to keep a monostable spring element in an instable state, an additional component supporting the monostable spring element in the instable state is required. For example, the retaining element is a flexible arm arranged on a rear case and the resilient force member rests in the biased state by support of the flexible arm. In an exemplary embodiment, the flexible arm may be biased by an outer circumference of a plunger. Thus, the resilient force member may change from the biased state into the relaxed state when the flexible arm releases. Alternatively, the retaining element is a cantilever beam arranged on a rear case, wherein the resilient force member rests in the biased state by support of the cantilever beam. In an exemplary embodiment, the cantilever beam is biased by an outer circumference of a plunger. Hence, the resilient force member may transition from the biased state into the relaxed state when the cantilever beam releases. 
     In an exemplary embodiment, the audible indicator is capable of producing an audible signal with a volume of at least 100 dB. 
     In an exemplary embodiment, the resilient force member is bent about a longitudinal bend such that the two-wing-shaped sections are at an angle of between 130 degrees and 160 degrees relative to each other. For example, the angle can be between 130 degrees and 140 degrees or between 140 degrees and 155 degrees or between 132 degrees and 142 degrees or between 134 degrees and 140 degrees or between 136 degrees and 138 degrees. In an exemplary embodiment, the angle is approximately or exactly 136 degrees or 137 degrees or 138 degrees or 148 degrees or 152 degrees. 
     The audible indicator may be part of a drug delivery device. 
     In some embodiments, a method of assembling a drug delivery device can comprise the steps of bending a resilient force member about a longitudinal axis extending generally from a first end of the resilient force member to a second end of the resilient force member located generally opposite the first end. For example, the first end may be a distal end and the second send may be a proximal end of the resilient force member. In some embodiments, the resilient force member can be bent about the longitudinal axis or bend such that the two-wing-shaped sections are at an angle of between about 130 degrees and about 160 degrees relative to each other. For example, the angle can be between 130 degrees and 140 degrees or between 140 degrees and 155 degrees or between 132 degrees and 142 degrees or between 134 degrees and 140 degrees or between 136 degrees and 138 degrees. In an exemplary embodiment, the angle is approximately or exactly 136 degrees or 137 degrees or 138 degrees or 148 degrees or 152 degrees. 
     Such bending may plastically deform the resilient force member to form two wing-shaped sections angled relative to each other about the longitudinal axis. It is contemplated that the two sections may have approximately the same shape or size. With such bending, the resilient force member may assume a first conformation. 
     The assembly method can also include flexing the resilient force member about an axis (A) running substantially perpendicular to the longitudinal axis or bend described above. Such flexing may elastically deform the resilient force member, converting its state from a relaxed state (S 1 ) to a biased state (S 2 ). In the biased state, the resilient force member can assume a second conformation different to the first conformation. 
     As described herein, the biased state can be unsupported (e.g., bistable), where no additional forces are applied to the resilient force member to maintain the second conformation. The biased state can also be maintained with support (e.g., monostable), where one or more additional or retaining forces are applied to the resilient force member to maintain the second conformation. Converting a bistable member from S 2  to S 1  can require application of an additional force to the resilient force member, while converting a monostable member from S 2  to S 1  can require at least partial removal of a retaining force from the resilient force member. Conversion from S 2  to S 1  can cause the resilient force member to generate a surprisingly loud sound signal. 
     The method can further include coupling the resilient force member of the drug delivery device. For example, the resilient force member can be fixedly coupled or movingly coupled to one or more parts of the drug delivery device. Fixed coupling can include co-molding, adhesive or chemical bonding, screws, etc. Moveable coupling can include locating at least part of the resilient force member within a complementary recess, or providing the resilient force member with one or more complementary recesses. For example, the resilient force member can include one or more protrusions designed to fit generally within one or more complementary recesses of a syringe carriers. The one or more protrusions can be located at various positions on the resilient force member. The resilient force member can also include one or more complementary recesses or a combination of protrusion or recess. Such an arrangement of one or more protrusions and recesses can facilitate efficient component transport, priming of the resilient force member, component assembly, or assembly of the device. 
     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 herein below and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present disclosure, and wherein: 
         FIG. 1  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a first embodiment, 
         FIG. 2  is a schematic perspective view of the audible indicator according to the first embodiment in a pre-assembled state, 
         FIG. 3  is a schematic perspective view of the audible indicator according to the first embodiment in a primed state, 
         FIG. 4  is a schematic longitudinal section of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the first embodiment in the primed state, 
         FIG. 5  is a diagram with a force-bending curve of the audible indicator according to the first embodiment, 
         FIG. 6  is a schematic longitudinal section of the drive sub assembly with the audible indicator according to  FIG. 4  in a relaxed state, 
         FIG. 7  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a second embodiment, 
         FIG. 8  is a schematic perspective view of the audible indicator according to the second embodiment, 
         FIG. 9  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the second embodiment, 
         FIG. 10  is a schematic longitudinal section of a proximal part of a drug delivery device in a primed state comprising the audible indicator according to the second embodiment, 
         FIG. 11  is a schematic longitudinal section of the proximal part of the drug delivery 
         FIG. 12  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a third embodiment, 
         FIG. 13  is a schematic perspective view of the audible indicator according to the third embodiment in a pre-assembled state, 
         FIG. 14  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the third embodiment, 
         FIG. 15  is a schematic longitudinal section of the drive subassembly comprising the audible indicator according to the third embodiment in a primed state, 
         FIG. 16  is a schematic longitudinal section of the drive sub assembly according to  FIG. 15  comprising the audible indicator according to the third embodiment in a relaxed state, 
         FIG. 17  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a fourth embodiment, 
         FIG. 18  is a schematic perspective view of the audible indicator according to the fourth embodiment in a pre-assembled state, 
         FIG. 19  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the fourth embodiment, 
         FIG. 20  is a schematic longitudinal section of a proximal part of a drug delivery device in an initial state comprising the audible indicator according to the fourth embodiment in a biased state, 
         FIG. 21  is a schematic longitudinal section of the proximal part of the drug delivery device in a primed state with the audible indicator according to  FIG. 20  in the biased state, 
         FIG. 22  is a schematic longitudinal section of the proximal part of the drug delivery device with the audible indicator according to  FIG. 20  in a relaxed state, 
         FIG. 23  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a fifth embodiment, 
         FIG. 24  is a schematic perspective view of the audible indicator according to the fifth embodiment in a pre-assembled state, 
         FIG. 25  is a schematic perspective view of a collar, 
         FIG. 26  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger, the collar according to  FIG. 25  and the audible indicator according to the fifth embodiment, 
         FIG. 27  is a schematic longitudinal section of a proximal part of a drug delivery device in an initial state comprising the audible indicator according to the fifth embodiment in a biased state, 
         FIG. 28  is a schematic longitudinal section of a cut out of the drug delivery device according to  FIG. 23  with the collar according to  FIG. 25 , 
         FIG. 29  is a schematic longitudinal section of the proximal part of the drug delivery device in a primed state with the audible indicator according to  FIG. 27 , 
         FIG. 30  is a schematic longitudinal section of the proximal part of the drug delivery device with the audible indicator according to  FIG. 27  in a relaxed state, 
         FIG. 31  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a sixth embodiment, 
         FIG. 32  is a schematic perspective view of the audible indicator according to the sixth embodiment in a pre-assembled state, 
         FIG. 33  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the sixth embodiment, 
         FIG. 34  is a schematic longitudinal section of a proximal part of a drug delivery device in a primed state comprising the audible indicator according to the sixth embodiment in a biased state, 
         FIG. 35  is a schematic longitudinal section of the proximal part of the drug delivery device with the audible indicator according to  FIG. 34  in a relaxed state, 
         FIG. 36  is a schematic perspective partial section of a drug delivery device comprising an audible indicator according to a seventh embodiment, 
         FIG. 37  is a schematic perspective view of the audible indicator according to the seventh embodiment in a pre-assembled state, 
         FIG. 38  is a schematic perspective view of a drive sub assembly of the drug delivery device comprising a rear case, a plunger and the audible indicator according to the seventh embodiment, 
         FIG. 39  is a schematic longitudinal section of a proximal part of a drug delivery device in a primed state comprising the audible indicator according to the seventh embodiment in a biased state, 
         FIG. 40  is a schematic longitudinal section of the proximal part of the drug delivery device with the audible indicator according to the seventh embodiment in a relaxed state. 
     
    
    
     Corresponding parts are marked with the same reference symbols in all figures. 
     DETAILED DESCRIPTION 
     In the present application, when the term “distal section/end” is used, this refers to the section/end of the device, or the sections/ends of the components thereof, which during use of the device is located closest to a medicament delivery site of a patient. Correspondingly, when the term “proximal section/end” is used, this refers to the section/end of the device, or the sections/ends of the components thereof, which during use of the device is pointing away from the medicament delivery site of the patient. 
       FIGS. 1 to 6  respectively show a first embodiment of an audible indicator  13  of an exemplary embodiment of a drug delivery device  1  which will be described further below.  FIG. 1  is a schematic perspective partial section of an exemplary embodiment of the drug delivery device  1  configured as an autoinjector. 
     In the shown exemplary embodiment, the drug delivery device  1  comprises a case  2  with a front case  2 . 1  and a rear case  2 . 2 . The case  2  is adapted to hold a medicament container  3 , such as a syringe. (The medicament container is referred to hereinafter as the “syringe  3 ”). The syringe  3  may be a pre-filled syringe, in particular a 1.0 ml pre-filled syringe, containing a medicament M and having a needle  4  arranged at a distal end of the syringe  3 . In another exemplary embodiment, the medicament container  3  may be a cartridge which includes the medicament M and engages a removable needle (e.g., by threads, snaps, friction, etc.). 
     The drug delivery device  1  further comprises a protective needle sheath  5  that is coupled to the needle  4 . For example, the protective needle sheath  5  is removably coupled to the needle  4 . The protective needle sheath  5  may be a rubber needle sheath or a rigid needle sheath which is composed of rubber and a full or partial plastic shell. 
     For sealing the syringe  3  proximally and for displacing a medicament M contained in the syringe  3  through the needle  4 , a stopper  6  is provided and arranged within the syringe  3 . 
     In the shown exemplary embodiment, the drug delivery device  1  comprises a needle shroud  7  that is telescopically coupled to the case  2  and movable between a first extended position relative to the case  2  in which the needle  4  is covered and a retracted position relative to the case  2  in which the needle  4  is exposed. Furthermore, a shroud spring  8  is arranged to bias the needle shroud  7  distally against the case  2 . 
     Furthermore, a drive spring  9  is arranged within the case  2 . Furthermore, a plunger  10  serves for forwarding a force of the drive spring  9  to the stopper  6 . The plunger  10  may be hollow, wherein the drive spring  9  is arranged within the plunger  10  biasing the plunger  10  distally against the case  2 . In another exemplary embodiment, the plunger  10  may be solid and the drive  9  may engage a proximal end of the plunger  10 . In the shown exemplary embodiment, the drive spring  9  is wrapped around an outer diameter of the plunger  10  and extends within the syringe  3 . The plunger  10  may comprise a proximal plunger section  10 . 1  and a distal plunger section  10 . 2  that are configured with different diameters, wherein the diameter of the proximal plunger section  10 . 1  is larger than the diameter of the distal plunger section  10 . 2  (not shown in detail in  FIGS. 1, 4 and 6 ). 
     Additionally, the drug delivery device  1  comprises a cap  11  that may be removably disposed at a distal end of the case  2 , in particular at a distal end of the front case  2 . 1 . The cap  11  may comprise grip features  11 . 1  for facilitating a removal of the cap  11 , e.g., by twisting and/or pulling the cap  11  off the case  2 . The cap  11  may further include a grip element  11 . 2 , e.g., a barb, a hook, a narrowed section, etc., arranged to engage the protective needle sheath  5 , the case  2  and/or the needle shroud  7 . 
     In the shown exemplary embodiment, a plunger release mechanism  12  is arranged for preventing release of the plunger  10  prior to retraction of the needle shroud  7  relative to the case  2  and for releasing the plunger  10  once the needle shroud  7  is sufficiently retracted. 
     Furthermore, a shroud lock mechanism  14  is arranged to prevent retraction of the needle shroud  7  relative to the case  2  when the cap  11  is in place, thereby avoiding unintentional activation of the drug delivery device  1 , e.g., if dropped, during shipping or packaging, etc. The shroud lock mechanism  14  may comprise one or more compliant beams  11 . 3  on the cap  11  and a respective number of apertures  7 . 6  in the needle shroud  7  adapted to receive each of the compliant beams  11 . 3 . 
     When the cap  11  is attached to the drug delivery device  1 , the compliant beams  11 . 3  abut a radial stop  2 . 15  on the case  2  which prevents the compliant beams  11 . 3  from disengaging the apertures  7 . 6 . Furthermore, when the cap  11  is attached to the drug delivery device  1 , an axial proximal movement of the cap  11  relative to the case  2  is limited by a rib  11 . 4  on the cap  11  that abuts the case  2 . 
     When the cap  11  is pulled off the case  2  distally, the compliant beams  11 . 3  may abut an edge of the aperture  7 . 6  and deflect to disengage the aperture  7 . 6 , allowing for removal of the cap  11  and the protective needle sheath  5  attached thereto. In an exemplary embodiment, the compliant beams  11 . 3  and/or the apertures  7 . 6  may be ramped to reduce force necessary to disengage the compliant beams  11 . 3  from the apertures  7 . 6 . 
     The drug delivery device  1  further comprises the audible indicator  13  according to the first embodiment for producing an audible feedback for a user or patient indicating completion of medicament delivery. In other words: The audible indicator  13  is provided to indicate to a user or a patient that the full dose of medicament M was spent. 
     In the following  FIGS. 2 to 6 , the audible indicator  13  according to the first embodiment will be explained in more detail. 
       FIGS. 2 and 3  are schematic perspective views of the audible indicator  13  according to the first embodiment, wherein  FIG. 2  shows the audible indicator  13  in a pre-assembly state and  FIG. 3  in a primed state. 
     The audible indicator  13  comprises a resilient force member  13 . 1 , e.g. having a substantially rectangular shape, comprising a longitudinal axis L running in parallel to the longest side of the outer circumference of the resilient force member  13 . 1 . In other embodiments, the resilient force member  13 . 1  may have a triangular shape or any other geometrical shape suitable to couple the audible indicator  13  to the autoinjector  1 . 
     The resilient force member  13 . 1  may be designed as a monostable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  13 . 1  is capable of residing in two states. That is, the resilient force member  13 . 1  may assume two different conformations, one of them stable with limited or no application of an external force and the other one unstable. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  13 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  13 . 1  can have a second conformation. In  FIG. 2 , the resilient force member  13 . 1  is in the relaxed state S 1  which can correspond to the pre-assembly state as well as to a state at the end of medicament delivery. 
     Regarding the first embodiment, the resilient force member  13 . 1  comprises a longitudinal bend  13 . 2 . The longitudinal bend  13 . 2  can be arranged generally in the centre of the resilient force member  13 . 1  running in parallel to the longitudinal axis L. The longitudinal bend  13 . 2  can divide the audible indicator  13  into two wing-shaped sections angled to each other with an angle less than 180. In in the illustrated perspective of  FIG. 2 , the wing-shaped sections are angled downwards. 
     Furthermore, the resilient force member  13 . 1  can comprise one or more tabs  13 . 3  projecting radially from the outer circumference. Specifically, the resilient force member  13 . 1  can include one, two, three four or more tabs  13 . 3 . As shown in  FIGS. 2 and 3 , the resilient force member  13 . 1  includes four tabs  13 . 3 , wherein one pair of tabs  13 . 3  is arranged opposite another pair of tabs  13 . 3 . In another embodiment (not shown), the resilient force member  13 . 1  can include two tabs  13 . 3  located generally opposite each other. The pairs of tabs  13 . 3  are arranged spaced to each other in the direction of the longitudinal axis L. In another exemplary embodiment, the number and arrangement of the tabs  13 . 3  may differ from the shown exemplary embodiment. In an exemplary embodiment, the tabs  13 . 3  may be angled with respect to the wing-shaped sections to facilitate assembly of the drug delivery device  1 . 
     The audible indicator  13  is coupled to the case  2  as shown in  FIG. 1 . In detail, the resilient force member  13 . 1  is held in the rear case  2 . 2  such that the longitudinal axis L is in parallel with a longitudinal extension of the drug delivery device  1 . The audible indicator  13  is coupled to the drug delivery device  1  by a snap connection, wherein one or more of the tabs  13 . 3  are engaged within a number of corresponding openings (not shown) in the rear case  2 . 2 . In another exemplary embodiment, the resilient force member  13 . 1  is held in the rear case  2 . 2  by a frictional connection, such as a screw or rivet connection or interference fit. 
     For assembling the audible indicator  13  into the drug delivery device  1 , the resilient force member  13 . 1  is bent in the center about an axis A running perpendicular to the longitudinal axis L. The bending angle is less than 90 degrees. This bending is achieved by applying a predetermined force onto or near the center point of the resilient force member  13 . 1  when engaging the tabs  13 . 3  within the openings in the rear case  2 . 2 . As a result, the resilient force member  13 . 1  changes from the relaxed state S 1  into the biased state S 2 . Two ends  13 . 1 . 1 ,  13 . 1 . 2  of the resilient force member  13 . 1  at opposite ends along the longitudinal axis L are angled upwards from the center point in the illustrated perspective of  FIG. 3 , which shows the biased state S 2 . Hence, the biased state S 2  corresponds with the primed state, wherein the resilient force member  13 . 1  stores a certain amount of energy. 
     After removing the applied force, the resilient force member  13 . 1  is held in the biased state S 2  as it is shown in  FIG. 4  and described below. 
       FIG. 4  shows a longitudinal section of an exemplary embodiment of a drive subassembly  1 . 1  of the drug delivery device  1 . 
     The drive sub assembly  1 . 1  is a sub assembly of the drug delivery device  1  and comprises the components required to deliver the medicament M. The drive subassembly  1 . 1  comprises the rear case  2 . 2 , the plunger  10  and the audible indicator  13  according to the first embodiment. The drug delivery device  1  further comprises a front sub assembly (not shown separately) to allow for flexibility as to the time and location of manufacture of the subassemblies and final assembly with the syringe  3 . 
     According to the present embodiment, the rear case  2 . 2  comprises two support arms  15 . 1  adapted to support an axial position of the syringe  3  during storage, transportation and medicament delivery. The support arms  15 . 1  project distally from a distal end of the rear case  2 . 2 . The rear case  2 . 2  further comprises an additional flexible arm  15 . 2  that projects distally from the distal end of the rear case  2 . 2  as well. The flexible arm  15 . 2  is adapted to damp impact forces and thus to stabilize the resilient force member  13 . 1  in its biased state S 2  during storage, transportation, and medicament delivery. 
     The resilient force member  13 . 1  is in the biased state S 2  and held in the rear case  2 . 2  by the snap connection as described above. The distally pointing end  13 . 1 . 1  of the resilient force member  13 . 1  is supported by a projection  15 . 2 . 1  of the flexible arm  15 . 2  arranged on a distal end of the flexible arm  15 . 2 . The proximally pointing end  13 . 1 . 2  of the resilient force member  13 . 1  is free and not in contact with any other component and located above the flexible arm  15 . 2  or another section of the rear case  2 . 2 . In an exemplary embodiment, the rear case  2 . 2  may comprise a plurality of flexible arms  15 . 2  that are arranged around a circumference of the proximal end of the rear case  2 . 2 . 
     Furthermore, the flexible arm  15 . 2  is deflected outwards supported by the outer circumference of the plunger  10  as is shown in  FIG. 4 . 
     After changing from the relaxed state S 1  into the biased state S 2  as described before, only a small force may be required to hold the resilient force member  13 . 1  in the biased state S 2 . This is achieved by the longitudinal bend  13 . 2  that provides a bended cross section of the resilient force member  13 . 1  which buckles into a new configuration by changing from the relaxed state S 1  into the biased state S 2 . In this configuration, a stiffness of the material structure is significantly reduced and thus only a small holding force is required to maintain the resilient force member  13 . 1  in the biased state S 2 .  FIG. 5  shows a diagram with a force-bending curve C of the resilient force member  13 . 1 . 
     The diagram comprises an abscissa x and an ordinate y. The abscissa x represents the bending deflection and the ordinate y represents the force required for achieving this deflection. The maximum of the force is represented by the coordinates x 2 , y 1 . Until this maximum is reached starting from the relaxed state S 1  at zero deflection and force, removal of the force results in the resilient force member  13 . 1  returning into the relaxed state S 1 . The maximum at the coordinates x 2 , y 1  represent an equilibrium point for the resilient force member  13 . 1  to change from the relaxed state S 1  into the biased state S 2 , i.e. the deflection increases further without further increase in force such that the curve arrives at the coordinates x 1 , y 2 . At this point, a much lower force than at the maximum is sufficient to hold the resilient force member  13 . 1  in the biased state S 2 . Thus, a large amount of energy can be stored by the resilient force member  13 . 1  in the biased state S 2  whilst maintaining a low holding force. 
     The low holding force in the biased state S 2  may cause a small frictional drag on the plunger  10 , diverting a small amount of the energy of the drive spring  9  away during medicament delivery, wherein the plunger  10  is moved distally by a release of the energy of the drive spring  9 . However, the derived energy is low due to the low holding force. 
       FIG. 6  shows a longitudinal section of the drive subassembly  1 . 1  of the drug delivery device  1  comprising the audible indicator  13  according to the first embodiment. 
     The resilient force member  13 . 1  is in the relaxed state S 1 , wherein the drug delivery device  1  is in a state at the end of a medicament delivery process. 
     For delivering the medicament M through the needle  4  into an injection site, e.g. a patient&#39;s skin, the plunger  10  is moved distally from a proximal position to a distal position due to an activation of the drive spring  9 . The activation of the drive spring  9  may be initiated by pressing a button or by depressing the needle shroud  7  as it is pushed against the injection site. 
     In  FIG. 6 , the plunger  10  has reached the distal position, wherein the flexible arm  15 . 2  is no longer engaged with the plunger  10 . When a proximal end of the plunger  10  passes the distal end of the flexible arm  15 . 2 , the flexible arm  15 . 2  is allowed to relax and can thus move radially inwards driven by the distally pointing end  13 . 1 . 1  of the resilient force member  13 . 1 . As the distally pointing end  13 . 1 . 1  of the resilient force member  13 . 1  moves, the resilient force member  13 . 1  can transition from a generally biased state S 2  into a generally relaxed state S 1  releasing stored energy to generate an audible signal, such as a click noise, due to a transition from the second conformation to the first conformation. Due to the large amount of stored energy, the audible signal can be generated with a high intensity, e. g. up to 100 decibels Signals of lesser intensity can also be generated. The proximally pointing end  13 . 1 . 2  of the resilient force member  13 . 1  can also swing radially inwards, thereby hitting the flexible arm  15 . 2  or the case  2  or another component of the drug delivery device  1 . This impact may also contribute to the generation of the audible signal. 
     The user or patient recognizing the audible signal knows that the medicament delivery process is finished and that the full dose was spent. 
     The drug delivery device  1  further comprises a carrier  16  to allow an accurate support of the syringe  3  during and after an assembling process. The carrier  16  is adapted to assemble, position and to hold the syringe  3  within the case  2 . 
       FIGS. 7 to 11  respectively show an audible indicator  113  according to a second embodiment. 
       FIG. 7  shows a schematic perspective partial section of an exemplary embodiment of a drug delivery device  101  comprising the audible indicator  113  according to the second embodiment. 
     The drug delivery device  101  is configured as an autoinjector nearly similar to the description of  FIG. 1 . 
     Except for the rear case  102 . 2  and the audible indicator  113 , all components of the drug delivery device  101  have the same configuration as described above in the  FIGS. 1 to 6 . The audible indicator  113  according to the second embodiment will be described in more detail in  FIG. 8 . The rear case  102 . 2  will be described in more detail in  FIG. 9 . 
       FIG. 8  is a perspective view of the audible indicator  113  according to the second embodiment. 
     The audible indicator  113  comprises a resilient force member  113 . 1  that may be configured as a bistable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  113 . 1  is capable of residing in two states. That is, the resilient force member  113 . 1  may assume two different stable conformations with limited or no application of an external force. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  113 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  113 . 1  can have a second conformation. The resilient force member  113 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 100  running in parallel to the longest side of the outer circumference of the resilient force member  113 . 1 . 
     The resilient force member  113 . 1  further comprises a longitudinal bend  113 . 2  that is arranged in the center of the resilient force member  113 . 1  running in parallel to the longitudinal axis L 100 . The longitudinal bend  113 . 2  can divide the audible indicator  113  into two wing-shaped sections angled to each other with an angle less than  180  degrees. In the illustrated perspective of  FIG. 8 , the wing-shaped sections are angled upwards. 
     The resilient force member  113 . 1  comprises a proximal spring section  113 . 3  and a distal spring section  113 . 4  divided by a cross bend  113 . 5  running in parallel to an axis A 100  that may be perpendicular to the longitudinal axis L 100 . 
     According to the present embodiment, the proximal spring section  113 . 3  is longer than the distal spring section  113 . 4  with respect to the longitudinal axis L 100 . In alternative embodiments, the proximal spring section  113 . 3  may be shorter than the distal spring section  113 . 4  or have the same length. 
     The resilient force member  113 . 1  is coupled to the rear case  102 . 2  as shown in the following  FIG. 9 . 
       FIG. 9  shows a schematic perspective view of an exemplary embodiment of the drive sub assembly  101 . 1  of the drug delivery device  101 . 
     The rear case  102 . 2  comprises two support arms  115 . 1  similar to the ones described in  FIG. 4 . 
     According to the present embodiment, the support arms  115 . 1  are configured with different lengths with respect to the longitudinal axis L 100  in an assembled state of the audible indicator  113 . In particular, the support arm  115 . 1  carrying the resilient force member  113 . 1  is shorter than the other support arm  115 . 1  in order to create space for arranging the resilient force member  113 . 1 . The resilient force member  113 . 1  may be coupled to the support arm  115 . 1  by a positive fit connection. For example, the proximal spring section  113 . 3  is received within a guiding recess arranged on an inner side of the support arm  115 . 1  and fixed, e.g. by a snap connection, by welding, gluing or by a frictional fit, wherein a remaining section of the proximal spring section  113 . 3  and the distal spring section  113 . 4  project distally from the support arm  115 . 1 . 
     The illustrated resilient force member  113 . 1  is in the biased state S 2 , wherein the distal spring section  113 . 4  is directed towards the outer circumference of a plunger  110  with respect to the proximal spring section  113 . 3 . 
     Due to the decreased diameter of a distal plunger section  110 . 2  (similar to the plunger  10  shown in  FIG. 1 ), the distal spring section  113 . 4  is radially spaced from the outer circumference of the distal plunger section  110 . 2 . Furthermore, the distal spring section  113 . 4  is not supported by any component of the drug delivery device  101  as can be seen in  FIG. 10 . 
       FIG. 10  shows a schematic longitudinal section of a proximal part of the drug delivery device  101  comprising the audible indicator  113  according to the second embodiment in the biased state S 2 , wherein the resilient force member  113 . 1  stores a certain amount of energy. The plunger  110  is in the proximal position. Thus, the drug delivery device  101  is ready to start a medicament delivery process. 
     For delivering a medicament M through a needle  104  into an injection site, the plunger  110  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 11  due to the activation of a drive spring  109  as described above. 
       FIG. 11  shows a schematic longitudinal section of the proximal part of the drug delivery device  101  with the plunger  110  in the distal position and the audible indicator  113  in the relaxed state S 1 . 
     At the end of medicament delivery, the proximal plunger section  110 . 1  abuts the distal spring section  113 . 4 . The abutting generates a force influence on the resilient force member  113 . 1 , which causes the distal spring section  113 . 5  to deflect radially outwards. As a result, the resilient force member  113 . 1 , in particular the distal spring section  113 . 4  releases the energy and thus can transition from a generally biased state S 2  into a generally relaxed state S 1 , thereby generating a recognizable audible signal. 
       FIGS. 12 to 16  respectively show an audible indicator  213  according to a third embodiment. 
       FIG. 12  shows a schematic perspective partial section of an exemplary embodiment of a drug delivery device  201  comprising the audible indicator  213  according to the third embodiment. 
     The drug delivery device  201  is configured as an autoinjector similar to the one described in  FIG. 1 . 
     Except for the rear case  202 . 2  and the audible indicator  213 , all components of the drug delivery device  201  may have the same configuration as described above in the  FIGS. 1 to 6 . The audible indicator  213  according to the third embodiment will be described in more detail in  FIG. 13 . The rear case  202 . 2  will be described in more detail in  FIG. 14 . 
       FIG. 13  is a perspective view of the audible indicator  213  according to the second embodiment. The audible indicator  213  comprises a resilient force member  213 . 1  that is configured as a bistable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  213 . 1  is capable of residing in two states. That is, the resilient force member  213 . 1  may assume two different stable conformations with limited or no application of an external force. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  213 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  213 . 1  can have a second conformation. The resilient force member  213 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 200  running in parallel to the longest side of the outer circumference of the resilient force member  213 . 1 . 
     The resilient force member  213 . 1  further comprises a longitudinal bend  213 . 2  that may be arranged generally in the center of the resilient force member  213 . 1  running in parallel to the longitudinal axis L 200 . The longitudinal bend  213 . 2  divides the resilient force member  213 . 1  into two wing-shaped sections angled to each other with an angle less than  180  degrees. In the illustrated perspective view of  FIG. 13 , the wing-shaped sections are angled upwards. 
     The resilient force member  213 . 1  is coupled to the rear case  202 . 2  as shown and described in the following  FIG. 14 . 
       FIG. 14  shows a schematic perspective view of an exemplary embodiment of a drive sub assembly  201 . 1  of the drug delivery device  201 . 
     The rear case  202 . 2  comprises two support arms  215 . 1  nearly similar to the ones shown in  FIG. 4 . 
     According to the present embodiment, the support arms  215 . 1  have the same lengths with respect the longitudinal axis L 200  in an assembled state of the audible indicator  213 . The support arms  215 . 1  respectively comprise a longitudinal recess  215 . 1 . 1 , wherein the resilient force member  213 . 1  is arranged within the longitudinal recess  215 . 1 . 1  of one of the support arms  215 . 1 . Thus, the resilient force member  213 . 1  may be proximally fixed to the support arm  215 . 1  by a positive connection, e. g. a snap connection, in order to prevent rotation of the resilient force member  213 . 1 . 
     The wing-shaped sections of the resilient force member  213 . 1  are bent upwards away from a plunger  210 . 
     For assembling the audible indicator  213  into the drug delivery device  201 , the resilient force member  213 . 1  is additionally bent in the center about the axis A 200  until a kink tip  213 . 3  is generated and the resilient force member  213 . 1  can transition from a generally relaxed state S 1  into a generally biased state S 2  as illustrated in  FIG. 15 , wherein the kink tip  213 . 3  points towards the outer circumference of the plunger  210 . This bending may be achieved by applying a predetermined force onto the center point of the resilient force member  213 . 1 . Likewise, this bending may be achieved by supporting the proximal end of the resilient force member  213 . 1  close to the kink point and applying a predetermined force, e.g. 20 N to the distal end of the resilient force member  213 . 1 . The kink tip  213 . 3  may be only achieved if the longitudinal bend  213 . 2  has a sufficiently small angle and bend radius and if a sufficiently small bend radius and sufficiently large deflection are applied when generating the kink tip  213 . 3 . 
       FIG. 15  shows a schematic longitudinal section of the drive sub assembly  201 . 1  comprising the audible indicator  213  according to the third embodiment in the biased state S 2 , wherein the resilient force member  213 . 1  stores a certain amount of energy. The plunger  10  is in the proximal position and the kink tip  213 . 3  is supported by the outer circumference of the plunger  210 . The drug delivery device  201  is ready to start a medicament delivery process. 
     For delivering a medicament M into an injection site, the plunger  210  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 16 . 
     At the end of medicament delivery, when the plunger  10  passes the kink tip  213 . 3  distally, a proximal plunger section  210 . 1  with an increased diameter with respect to a distal plunger section  210 . 1 , the kink tip  213 . 3  generates a force influence on the resilient force member  213 . 1 , which causes the kink tip  213 . 3  to deflect radially outwards as illustrated in  FIG. 16 . 
       FIG. 16  shows a schematic longitudinal section of the drive sub assembly  201 . 1  with the plunger  210  in the distal position and the audible indicator  213  in the relaxed state S 1 . 
     Due to the deflection of the kink tip  213 . 3 , the energy is released from the resilient force member  213 . 1 , whereby the resilient force member  213 . 1  is straightened with respect to the longitudinal axis L 200 . By releasing the stored energy, the resilient force member  213 . 1  can transition from a generally biased state S 2  into a generally relaxed state S 1 , thereby generating a recognizable audible signal. 
       FIGS. 17 to 22  respectively show an audible indicator  313  according to a fourth embodiment. 
       FIG. 17  shows a schematic perspective partial section of an exemplary embodiment of a drug delivery device  301  comprising the audible indicator  313  according to a fourth embodiment. 
     The drug delivery device  301  is configured as an autoinjector similar to the one described in  FIG. 1 . 
     Except for the rear case  302 . 2  and the audible indicator  313 , all components of the drug delivery device  301  have the same configuration as described above in the  FIGS. 1 to 6 . The audible indicator  313  according to the fourth embodiment will be described in more detail in  FIG. 18 . The rear case  302 . 2  will be described in more detail in  FIG. 19 . 
       FIG. 18  is a perspective view of the audible indicator  313  according to the fourth embodiment. 
     The audible indicator  313  comprises a resilient force member  313 . 1  that is configured as a bistable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  313 . 1  is capable of residing in two states. That is, the resilient force member  313 . 1  may assume two different stable conformations with limited or no application of an external force. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  313 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  313 . 1  can have a second conformation. The resilient force member  313 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 300  running in parallel to the longest side of the outer circumference of the resilient force member  313 . 1 . 
     The resilient force member  313 . 1  further comprises a longitudinal bend  313 . 2  that can be arranged generally in the center of the resilient force member  313 . 1  running in parallel to the longitudinal axis L 300 . The longitudinal bend  313 . 2  can divide the resilient force member  313 . 1  into two wing-shaped sections angled to each other with an angle less than 180 degrees. 
     The resilient force member  313 . 1  may be further divided into a proximal spring section  313 . 3 , an intermediate spring section  313 . 4  and a distal spring section  313 . 5  due to a first cross bend  313 . 6  and a second cross bend  313 . 7  respectively running in parallel to an axis A 300  that may be perpendicular to the longitudinal axis L 300 . 
     Additionally, the distal spring section  313 . 5  comprises a hook-like projection  313 . 5 . 1  arranged on a distal end of the distal spring section  313 . 5  and protruding diagonally towards a proximal end of the distal spring section  313 . 5 . 
     The resilient force member  313 . 1  is coupled to the rear case  302 . 2  as illustrated in  FIG. 19 . 
       FIG. 19  shows a schematic perspective view of a drive sub assembly  301 . 1  of the drug delivery device  1  comprising the rear case  302 . 2 , a plunger  310  and the audible indicator  313  according to the fourth embodiment. 
     The rear case  302 . 2  comprises two support arms  315 . 1  nearly similar to the ones described in  FIG. 4 . 
     According to the present embodiment, the support arms  315 . 1  have the same length with respect to the longitudinal axis L 300  in an assembled state of the audible indicator  313 . 
     Alternatively, the support arm  315 . 1  which is not connected to the resilient force member  313 . 1  could be any length. The support arms  315 . 1  respectively comprise a guiding recess  315 . 1 . 1 , wherein the resilient force member  313 . 1  is received within the guiding recess  315 . 1 . 1  of one of the support arms  315 . 1 . Particularly, the proximal spring section  313 . 3  is arranged within the guiding recess  315 . 1 . 1 , which may comprise guiding tracks for a positive locking of the resilient force member  313 . 1 . The arrangement of the proximal spring section  313 . 3  within the guiding recess  315 . 1 . 1  is supported by two locking tabs  315 . 1 . 2  that decrease a cross section of the guiding recess  315 . 1 . 1  radially above the proximal spring section  313 . 3 . 
     The intermediate spring section  313 . 4  and the distal spring section  313 . 5  projects distally from the support arm  315 . 1 , wherein the intermediate spring section  313 . 4  is angled with respect to the proximal spring section  313 . 3  radially outwards as best shown in  FIG. 20 . The distal spring section  313 . 5  is angled radially inwards with respect to the intermediate spring section  313 . 4  and thus bent towards the plunger  310  as illustrated in  FIG. 20 . By bending the distal spring section  313 . 5  radially inwards, the resilient force member  313 . 1  can transition from the relaxed state S 1  into the biased state, thereby storing energy. 
       FIG. 20  shows a schematic longitudinal section of a proximal part of the drug delivery device  1  comprising the audible indicator  313  according to the fourth embodiment in the biased state S 2 , wherein the drug delivery device  301  is in an initial state prior to medicament delivery. 
     The resilient force member  313 . 1  is supported by a supporting rib  307 . 7  arranged within an inner circumference of a needle shroud  307 . In particular, the hook-like projection  313 . 5 . 1  abuts against the supporting rib  307 . 7 . Thus, the engagement between the hook-like projection  313 . 5 . 1  and the supporting rib  307 . 7  prevents a premature activation of the resilient force member  313 . 1  during storage and transportation. Alternatively, there may be arranged more than one supporting rib  307 . 7   
       FIG. 21  shows a schematic longitudinal section of the proximal part of the drug delivery device  301  comprising the audible indicator  313  according to the fourth embodiment in the biased state S 2 , wherein the drug delivery device  301  is in a primed state. 
     Hereby, the drug delivery device  301  is primed for medicament delivery and thus ready to use. During priming, the needle shroud  307  was moved proximally into a case  302 , thus the supporting rib  307 . 7  moves proximally behind the hook-like projection  313 . 5 . 1 , thereby generating space for the distal spring section  313 . 5  to deflect radially outwards as illustrated in  FIG. 22 . The plunger  310  is in the proximal position, the drug delivery device  301  is ready to start medicament delivery. 
     For delivering a medicament M into an injection site, the plunger  310  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 22 . 
       FIG. 22  shows a schematic longitudinal section of the proximal part of the drug delivery device  301  with the audible indicator  313  in the relaxed state S 1  after medicament delivery. 
     At the end of medicament delivery, the proximal plunger section  310 . 1  abuts the distal spring section  313 . 5 . The abutting generates a force influence on the resilient force member  313 . 1 , which causes the distal spring section  313 . 5  to deflect radially outwards. 
     Due to the deflection of the distal spring section  313 . 5 , the energy is released from the resilient force member  313 . 1 . By releasing the stored energy, the resilient force member  313 . 1  can transition from a generally biased state S 2  into a generally relaxed state S 1 , thereby generating a recognizable audible signal. 
       FIGS. 23 to 30  respectively show an audible indicator  413  according to a fifth embodiment. 
       FIG. 23  is a schematic perspective partial section of an exemplary embodiment of a drug delivery device  401  comprising the audible indicator  413  according to the fifth embodiment. 
     The drug delivery device  401  is configured as an autoinjector similar to the one described in  FIG. 1 . 
     Except for the rear case  402 . 2  and the audible indicator  413 , all components of the drug delivery device  401  substantially have the same configuration as described above in the  FIGS. 1 to 6 . The audible indicator  413  according to the fifth embodiment will be described in more detail in  FIG. 24 . The rear case  402 . 2  will be described in more detail in  FIG. 26 . 
       FIG. 24  is a perspective view of the audible indicator  413  according to the fifth embodiment. 
     The audible indicator  413  comprises a resilient force member  413 . 1  that is configured as a bistable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  413 . 1  is capable of residing in two states. That is, the resilient force member  413 . 1  may assume two different stable conformations with limited or no application of an external force. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  413 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  413 . 1  can have a second conformation. The resilient force member  413 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 400  running in parallel to the longest side of the outer circumference of the resilient force member  413 . 1 . 
     The resilient force member  413 . 1  further comprises a longitudinal bend  413 . 2  that can be arranged generally in the center of the resilient force member  413 . 1  running in parallel to the longitudinal axis L 400 . The longitudinal bend  413 . 2  can divide the resilient force member  413 . 1  into two wing-shaped sections angled to each other with an angle less than  180  degrees. 
     The resilient force member  413 . 1  can be further divided into a proximal spring section  413 . 3 , an intermediate spring section  413 . 4  and a distal spring section  413 . 5  due to a first cross bend  413 . 6  and a second cross bend  413 . 7  respectively running in parallel to an axis A 400  that can be perpendicular to the longitudinal axis L 400 . 
     According to  FIG. 24 , the resilient force member  413 . 1  is in the biased state S 2 , wherein the distal spring section  413 . 5  is bent radially inwards with respect to the intermediate spring section  413 . 4  over the second cross bend  413 . 7 . 
     The resilient force member  413 . 1  is coupled to the rear case  402 . 2  as illustrated in  FIG. 26 . 
       FIG. 25  shows a schematic perspective view of a collar  418  that is assembled to a drive sub assembly  401 . 1  as illustrated in  FIG. 26 . 
     The collar  418  comprises a collar ramp  418 . 1  that is arranged on an outer circumference of the collar  418  and configured as a diagonally ramped surface. 
       FIG. 26  shows a schematic perspective view of the drive sub assembly  401 . 1  of the drug delivery device  401  comprising the rear case  402 . 2 , a plunger  410 , the audible indicator  413  according to the fifth embodiment and the collar  418 . 
     The rear case  402 . 2  comprises two support arms  415 . 1  similar to the ones described in  FIG. 4 . 
     According to the present embodiment, the support arms  415 . 1  have the same length with respect to the longitudinal axis L 400  in an assembled state of the audible indicator  413 . A fixing element  415 . 2  is arranged between the support arms  415 . 1  in order to receive the resilient force member  413 . 1 . 
     The intermediate spring section  413 . 4  and the distal spring section  413 . 5  project distally from the fixing element  415 . 2 , wherein the intermediate spring section  413 . 4  is angled with respect to the proximal spring section  413 . 3  radially inwards. The distal spring section  413 . 5  is angled radially outwards with respect to the intermediate spring section  413 . 4  and thus bent away from the plunger  410  as illustrated in  FIG. 27 . By bending the distal spring section  413 . 5  radially outwards, the resilient force member  413 . 1  can transition from a generally relaxed state S 1  into a generally biased state S 2 , thereby storing energy. 
     The resilient force member  413 . 1 , in particular the bent distal spring section  413 . 5  is supported by an outer circumference of the collar  418  that is coupled distally with a distal plunger section  410 . 2 , e. g. by a threaded connection. Thus, the engagement between the distal spring section  413 . 5  and the collar  418  prevents a premature activation of the resilient force member  413 . 1  during storage and transportation. 
       FIG. 27  shows a schematic longitudinal section of a proximal part of the drug delivery device  401  comprising the audible indicator  413  according to the fifth embodiment in the biased state S 2 , wherein the drug delivery device  401  is in an initial state prior to medicament delivery. The collar  418  is prevented against rotation by a number of locking ribs  407 . 8  as illustrated in  FIG. 28 . 
       FIG. 28  shows a schematic longitudinal detail section of the drug delivery device  401  according to  FIG. 27  illustrating the collar  418  and the number of locking ribs  407 . 8 . 
     According to the illustrated embodiment, a needle shroud  407  is arranged that comprises two locking ribs  407 . 8  arranged on an inner circumference of the needle shroud  407 . Alternatively, there may be arranged only one or more than two locking ribs  407 . 8 . 
     The locking ribs  407 . 8  extends in parallel to a longitudinal extension of the drug delivery device  1  and projects radially inwards, whereby the collar ramp  418 . 1  projects between the locking ribs  407 . 8  thus preventing a rotational movement of the collar  418  with respect to the needle shroud  407  during storage and transportation. 
     During priming of the drug delivery device  401 , a force is required to move the needle shroud  407  proximally with respect to the rear case  402 . 2 . As a result, the locking ribs  407 . 8  move along the collar ramp  418 . 1 . This movement causes a rotation of the collar  418  with respect to the plunger  410 . Due to the threaded connection, the collar  418  is moved distally with respect to the resilient force member  413 . 1  and the bent distal spring section  413 . 5  is unsupported as illustrated in  FIG. 29 . 
       FIG. 29  shows a schematic longitudinal section of the proximal part of the drug delivery device  1  comprising the audible indicator  413  according to the fifth embodiment in the biased state S 2 , wherein the drug delivery device  401  is in the primed state and the distal spring section  413 . 5  is unsupported. 
     Thus, the drug delivery device  401  is ready to start medicament delivery. 
     For delivering a medicament M through a needle  404  into an injection site, the plunger  410  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 30  due to the activation of a drive spring  409  as described above. 
       FIG. 30  shows a schematic longitudinal section of the proximal part of the drug delivery device  401  with the audible indicator  413  in the relaxed state S 1  after medicament delivery. 
     At the end of medicament delivery, a proximal plunger section  410 . 1  with an increased diameter with respect to the distal plunger section  410 . 2  abuts the distal spring section  413 . 5 . The abutting generates a force influence on the resilient force member  413 . 1 , which causes the distal spring section  413 . 5  to deflect radially inwards. 
     Due to the deflection of the distal spring section  413 . 5 , the energy is released from the resilient force member  413 . 1 . By releasing the stored energy, the resilient force member  413 . 1  can transition from a generally biased state S 2  into a generally relaxed state S 1 , thereby generating a recognizable audible signal. 
       FIGS. 31 to 35  respectively show an audible indicator  513  according to a sixth embodiment. 
       FIG. 31  shows a schematic perspective partial section of an exemplary embodiment of a drug delivery device  501  comprising an audible indicator  513  according to the sixth embodiment. 
     The drug delivery device  501  is configured as an autoinjector similar to the one described in  FIG. 1 . 
     Except for the rear case  502 . 2  and the audible indicator  513 , all components of the drug delivery device  1  substantially have the same configuration as described above in  FIGS. 1 to 6 . The audible indicator  513  according to the fifth embodiment will be described in more detail in  FIG. 32 . The rear case  502 . 2  will be described in more detail in  FIG. 33 . 
       FIG. 32  is a perspective view of the audible indicator  513  according to the sixth embodiment. 
     The audible indicator  513  comprises a resilient force member  513 . 1  that is configured as a bistable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  513 . 1  is capable of residing in two states. That is, the resilient force member  513 . 1  may assume two different stable conformations with limited or no application of an external force. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  513 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  513 . 1  can have a second conformation. The resilient force member  513 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 500  running in parallel to the longest side of the outer circumference of the resilient force member  513 . 1 . 
     The resilient force member  513 . 1  further comprises a longitudinal bend  513 . 2  that can be arranged generally in the enter of the resilient force member  513 . 1  running in parallel to the longitudinal axis L 500 . The longitudinal bend  513 . 2  divides the resilient force member  513 . 1  into two wing-shaped sections angled to each other with an angle less than  180  degrees. 
     The resilient force member  513 . 1  can be further divided into a proximal spring section  513 . 3  and a distal spring section  513 . 4  due to a cross bend  513 . 5  that extends in parallel to an axis A 500  that may be perpendicular to the longitudinal axis L 500 . 
     According to  FIG. 32 , the resilient force member  513 . 1  is in the biased state S 2 , wherein the distal spring section  513 . 5  is bent about a certain angle over the cross bend  513 . 5  with respect to the proximal spring section  513 . 3 . 
     With respect to the longitudinal axis L 500  the resilient force member  513 . 1  of the present embodiment is smaller than the resilient force member  513 . 1  of the audible indicator  413  of the fifth embodiment. 
     The resilient force member  513 . 1  is coupled to the rear case  502 . 2  as illustrated in  FIG. 33 . 
       FIG. 33  shows a schematic perspective view of a drive sub assembly  501 . 1  of the drug delivery device  501  comprising the rear case  502 . 2 , a plunger  510 , and the audible indicator  513  according to the sixth embodiment. 
     The rear case  502 . 2  comprises two support arms  515 . 1  similar to the ones described in  FIG. 4 . 
     According to the present embodiment, the support arms  515 . 1  have the same length with respect to the longitudinal axis L 500  in an assembled state of the audible indicator  513 . 
     The resilient force member  513 . 1  is coupled to the plunger  510 , wherein the distal spring section  513 . 4  is fixed to a proximal plunger section  510 . 1  by a force fit, form fit and/or adhesive bond in order to prevent a rotational movement of the resilient force member  513 . 1  with respect to the plunger  510 . The proximal spring section  513 . 3  defines a free end of the resilient force member  513 . 1  that protrudes beyond the edge of the proximal plunger section  510 . 1  as illustrated in  FIG. 34 . 
     The proximal spring section  513 . 3  is angled radially inwards with respect to the distal spring section  513 . 4 ; hence the resilient force member  513 . 1  is in the biased state S 2 , thereby storing energy. 
     The resilient force member  513 . 1 , in particular the proximal spring section  513 . 3 , is supported by the rear case  502 . 2  as illustrated and described in more detail in  FIG. 34 . 
       FIG. 34  shows a schematic longitudinal section of a proximal part of the drug delivery device  501  comprising the audible indicator  513  according to the sixth embodiment. 
     The drug delivery device  501  is in a primed state prior to use, wherein the plunger  510  is in a proximal position. 
     The proximal spring section  513 . 3  is supported by a supporting protrusion  502 . 2 . 1  arranged on an inner side of a proximal end of the rear case  502 . 2  projecting distally towards the plunger  510 . The supporting protrusion  502 . 2 . 1  may be configured as a protruding section or as a circulated ring-shaped protrusion. 
     The proximal spring section  513 . 3  is arranged behind the supporting protrusion  502 . 2 . 1  with respect to a radial inward direction and is thus prevented against deflecting radially outwards during storage, transportation and priming of the drug delivery device  501 . Furthermore, the cross bend  513 . 5  defines a kink enabling the bistability of the resilient force member  513 . 1 . 
     For delivering a medicament M through a needle  504  into an injection site, the plunger  510  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 35  due to the activation of a drive spring  509  as described above. Because the distal spring section  513 . 4  is fixed to the proximal plunger section  510 . 1 , the resilient force member  513 . 1  follows the axial movement of the plunger  510 . As a consequence, the resilient force member  513 . 1  moves distally with respect to the rear case  502 . 2  away from the supporting protrusion  502 . 2 . 1 , wherein the proximal spring section  513 . 3  becomes unsupported. 
     At the end of medicament delivery, an activating rib  507 . 9  arranged on an inner circumference of a needle shroud  507  abuts the resilient force member  513 . 1  at the cross bend  513 . 5 . This abutting generates a force influence on the resilient force member  513 . 1 , which stimulates the proximal spring section  413 . 5  to deflect radially outwards. 
     Due to the deflection of the proximal spring section  513 . 5 , the energy is released from the resilient force member  513 . 1 . By releasing the stored energy, the resilient force member  513 . 1  can transition from a generally biased state S 2  into a generally relaxed state S 1  as illustrated in  FIG. 35 , thereby generating a recognizable audible signal. 
       FIG. 35  shows a schematic longitudinal section of the proximal part of the drug delivery device  501 , wherein the audible indicator  513  is in the biased state S 2 , but on the point of activation as it is starting to contact the needle shroud  507 . 
       FIGS. 36 to 40  respectively show an audible indicator  613  according to a seventh embodiment. 
       FIG. 36  shows a schematic perspective partial section of an exemplary embodiment of a drug delivery device  601  comprising an audible indicator  613  according to a seventh embodiment. 
     The drug delivery device  601  is configured as an autoinjector similar to the one described in  FIG. 1 . 
     Except for the rear case  602 . 2  and the audible indicator  613 , all components of the drug delivery device  601  substantially have the same configuration as described above in the  FIGS. 1 to 6 . The audible indicator  613  according to the seventh embodiment will be described in more detail in  FIG. 32 . The rear case  602 . 2  will be described in more detail in  FIG. 37 . 
       FIG. 37  is a perspective view of the audible indicator  613  according to the seventh embodiment. 
     The audible indicator  613  comprises a resilient force member  613 . 1  that is configured as a monostable leaf spring comprising a resilient material, e. g. spring steel or spring plastic. Thus, the resilient force member  613 . 1  is capable of residing in two states. That is, the resilient force member  613 . 1  may assume two different conformations, one of them stable with limited or no application of an external force and the other one unstable. For example, these two states can include a first or relaxed state S 1  (or pre-assembly state, or trigged state), in which the resilient force member  613 . 1  has a first conformation. In a second or biased state S 2  (or primed state), the resilient force member  613 . 1  can have a second conformation. The resilient force member  613 . 1  may comprise a substantially rectangular shape and a longitudinal axis L 600  running in parallel to the longest side of the outer circumference of the resilient force member  613 . 1 . 
     The resilient force member  613 . 1  further comprises a longitudinal bend  613 . 2  that may be arranged generally in the center of the resilient force member  613 . 1  running in parallel to the longitudinal axis L 600 . The longitudinal bend  613 . 2  divides the resilient force member  613 . 1  into two wing-shaped sections angled to each other with an angle less than  180  degrees. 
     The resilient force member  613 . 1  is coupled to the rear case  602 . 2  as illustrated in  FIG. 38 . 
       FIG. 38  shows a schematic perspective view of a drive sub assembly  601 . 1  of the drug delivery device  601  comprising the rear case  602 . 2 , a plunger  610 , and the audible indicator  613  according to the seventh embodiment. 
     The rear case  602 . 2  comprises two support arms  615 . 1  similar to the ones described in  FIG. 14 . 
     According to the present embodiment, the support arms  615 . 1  have the same length with respect to the longitudinal axis L 600  in an assembled state of the audible indicator  613 . The support arms  615 . 1  respectively comprise a longitudinal recess  615 . 1 . 1 , wherein the resilient force member  613 . 1  is arranged within the longitudinal recess  615 . 1 . 1  of one of the support arms  615 . 1 . Thereby, the resilient force member  613 . 1  is proximally and distally fixed to the support arm  615 . 1  by a positive connection, e. g. a snap connection, in order to prevent a rotation of the resilient force member  613 . 1 . Alternatively, the fixing could allow rotation of the ends of the resilient force member  613 . 1 , but prevent translational movement. 
     The wing-shaped sections of the resilient force member  613 . 1  are bent upwards away from the plunger  610 . 
     According to the present embodiment, the audible indicator  613  comprises only a monostability in contrast to the bistable resilient force members  113 . 1  to  513 . 1  of some of the other embodiments. That means, the resilient force member  613 . 1  needs to be supported for remaining in a biased state S 2  as illustrated and described in more detail in  FIG. 39 . 
       FIG. 39  shows a schematic longitudinal section of a proximal part of the drug delivery device  601 , wherein the resilient force member  613 . 1  is in the biased state S 2  and the drug delivery device  601  is in a primed state prior to use, wherein the plunger  610  is in a proximal position. 
     The support of the resilient force member  613 . 1  is achieved by a cantilever beam  602 . 2 . 1  arranged on a section of the support arm  615 . 1  behind the resilient force member  613 . 1  with respect to a radial inward direction. Thus, the resilient force member  613 . 1  rests on the cantilever beam  602 . 2 . 1 , whereby the resilient force member  613 . 1  is additionally bent in the center about an axis A 600  that runs generally perpendicular to the longitudinal axis L 600 , thereby generating a kink tip  613 . 3 . 
     The cantilever beam  602 . 2 . 1  is biased radially outwards by an outer circumference of the plunger  610 . According to the present embodiment, the rear case  602 . 2  comprises two cantilever beams  602 . 2 . 1 . Alternatively, the rear case  602 . 2  may comprise only one or more than two cantilever beams  602 . 2 . 1 . In embodiments with more than one resilient force member  613 . 1 , each cantilever beam  602 . 2 . 1  may be arranged to support one respective resilient force member  613 . 1 . 
     For delivering a medicament M into an injection site, the plunger  610  has to be moved distally from the proximal position to the distal position as illustrated in  FIG. 40 . During medicament delivery, the resilient force member  613 . 1  is supported by the cantilever beam  602 . 2 . 1 . During movement of the plunger  610 , a friction is induced on the cantilever beam  602 . 2 . 1 . 
     At the end of medicament delivery, when a proximal end of the plunger  610  passes the cantilever beam  602 . 2 . 1  distally, the cantilever beam  602 . 2 . 1  is free to relax radially inwards. As a consequence, the resilient force element  613 . 1  relaxes, thereby generating a recognizable audible signal. 
       FIG. 40  shows a schematic longitudinal section of the proximal part of the drug delivery device  601 , wherein the resilient force element  613  is in the relaxed state S 1  after medicament delivery. 
     The skilled person readily understands that application of the audible indicator  13  is not limited to auto-injectors  1 . Instead, the audible indicator  13  may likewise be applied in a manually operated drug delivery device  1  for indicating that the plunger  10  has been completely moved into the distal position. 
     In an exemplary embodiment, the bistable or monostable resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may consist of stainless steel, e.g. stainless steel  301  full hard. In an exemplary embodiment the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may have a substantially rectangular form, in particular with a length of  70  mm. A nominal width flat of the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may be approximately  8 mm. The longitudinal bend  13 . 2 ,  113 . 2 ,  213 . 2 ,  313 . 2 ,  413 . 2 ,  513 . 2 ,  613 . 2  may be positioned to bisect the width of the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1 . A thickness of the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may be  0 . 1  mm. In the first conformation, the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may be bent about the longitudinal bend  13 . 2 ,  113 . 2 ,  213 . 2 ,  313 . 2 ,  413 . 2 ,  513 . 2 ,  613 . 2  such that the two-wing-shaped sections are at an angle of between 130 and 160 degrees or between 130 degrees and 150 degrees. For example, the angle can be between 130 degrees and 140 degrees or between 140 degrees and 155 degrees or between 132 degrees and 142 degrees or between 134 degrees and 140 degrees or between 136 degrees and 138 degrees. In an exemplary embodiment the angle is approximately or exactly 136 degrees or 137 degrees or 138 degrees or 148 degrees or 152 degrees relative to each other. 
     In other exemplary embodiments, the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may have a different length, e.g. approximately 30 mm or 43 mm. 
     In order to kink the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  to move it from the first conformation to the second conformation a force in the range from 3 N to 14 N may be applied to a free end of the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  or to a point near the free end, e.g. approximately 13 mm from the free end. Application of this force may result in an extension of 2 mm to 3.5 mm of the free end from its position in the first conformation. 
     A force required to activate the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  to move it from its second conformation to its first conformation may be in a range from 0.2 N to 0.4 N applied to the free end of the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  or to a point near the free end, e.g. approximately 1 mm to 2 mm from the free end. 
     A particularly clear click noise and reduced kinking and activation forces may be achieved by kinking the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1 , activating it and then kinking it again before inserting it into the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601 . 
     When activated, the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may produce an audible signal with a volume of at least 100 dB, e.g. measured at a distance of approximately 0.5 m. As opposed to a resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  with a bend angle of e.g. 152 degrees, the volume produced by a resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  having a bend angle of e.g. 136 degrees can be increased by approximately  6  dB, which corresponds to a factor  2  increase in amplitude. 
     When inserted in a drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601 , the resilient force member  13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  may produce an audible signal with a volume of at least 100 dB(A), e.g. measured at a distance of approximately 150 mm. In a test setup, the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  was placed in a sound-absorbing environment on a table with the needle shroud  7 ,  307 ,  407 ,  507  ahead. An elastomeric layer was located between the needle shroud  7 ,  307 ,  407 ,  507  and the table to acoustically decouple the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  from the table. Two microphones (e.g. ROGA MI-17 (IEPE)) were placed laterally from the the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  opposite each other at a distance of 150 mm, respectively and 170 mm above the table. A first test was performed with a user holding and operating the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  with the right hand closed around the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601 , wherein the fingers of the hand covered one side of the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  directed towards one of the microphones and wherein the opposite side pointing towards the other microphone was covered by the palm of the hand. The volume of the audible signal on the finger side microphone was at least 100 dB(A) while the volume on the palm side microphone was lower than 100 dB(A). Another test was performed with a user holding and operating the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  only with the fingertips of the right hand, wherein the palm of the hand was located between the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  and one of the microphones; however, the drug delivery device  1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  was not touched by the palm. The volume of the audible signal acquired by both microphones was at least 100 dB(A), wherein the volume detected by the palm side microphone was slightly lower than the volume detected by the other microphone. 
     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-(w-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(w-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. HDl 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 
       1 ,  101 ,  201 ,  301 ,  401 ,  501 ,  601  drug delivery device 
       1 . 1 ,  101 . 1 ,  201 . 1 ,  301 . 1 ,  401 . 1 ,  501 . 1 ,  601 . 1  drive sub assembly 
       2  case 
       2 . 1  front case 
       2 . 2 ,  102 . 1 ,  202 . 1 ,  302 . 1 ,  402 . 1 ,  502 . 1 ,  602 . 2  rear case 
       502 . 2 . 1  supporting protrusion 
       602 . 2 . 1  cantilever beam 
       2 . 15  radial stop 
       3  medicament container, syringe 
       4 ,  104 ,  404 ,  504  needle 
       5  protective needle sheath 
       6  stopper 
       7 ,  307 ,  407 ,  507  needle shroud 
       7 . 6  apertures 
       307 . 7  supporting rib 
       407 . 8  locking rib 
       507 . 9  activation rib 
       8  shroud spring 
       9 ,  109 ,  409 ,  509  drive spring 
       10 ,  110 ,  210 ,  310 ,  410 ,  510 ,  610  plunger 
       10 . 1 ,  110 . 1 ,  210 . 1 ,  310 . 1 ,  410 . 1 ,  510 . 1  proximal plunger section 
       10 . 2 ,  110 . 2 ,  210 . 2 ,  310 . 2 ,  410 . 1 ,  510 . 2  distal plunger section 
       11  cap 
       11 . 1  grip features 
       11 . 2  grip element 
       11 . 3  compliant beams 
       11 . 4  rib 
       12  plunger release mechanism 
       13 ,  113 ,  213 ,  313 ,  413 ,  513 ,  613  audible indicator 
       13 . 1 ,  113 . 1 ,  213 . 1 ,  313 . 1 ,  413 . 1 ,  513 . 1 ,  613 . 1  resilient force member 
       13 . 1 . 1  distally pointing end 
       13 . 1 . 2  proximally pointing end 
       13 . 2 ,  113 . 2 ,  213 . 2 ,  313 . 2 ,  413 . 2 ,  513 . 2 ,  613 . 2  longitudinal bend 
       13 . 3  tabs 
       113 . 3  proximal spring section 
       113 . 4  distal spring section 
       113 . 5  cross bend 
       213 . 3  kink tip 
       313 . 3 ,  413 . 4 ,  513 . 3  proximal spring section 
       313 . 4 ,  413 . 4  intermediate spring section 
       313 . 5 ,  413 . 5  distal spring section 
       313 . 5 . 1  hook-like projection 
       313 . 6 ,  413 . 6  first cross bend 
       313 . 7 ,  413 . 7  second cross bend 
       513 . 4  distal spring section 
       513 . 5  cross bend 
       613 . 3  kink tip 
       14  shroud lock mechanism 
       15 . 1 ,  115 . 1 ,  215 . 1 ,  315 . 1 ,  415 . 1 ,  515 . 1 ,  615 . 1  support arms 
       215 . 1 . 1  longitudinal recess 
       315 . 1 . 1  guiding recess 
       315 . 1 . 2 ,  415 . 2 . 1  locking tabs 
       415 . 2  fixing element 
       615 . 1 . 1  longitudinal recess 
       15 . 2  flexible arm 
       15 . 2 . 1  projection 
       16  carrier 
       418  collar 
       418 . 1  collar ramp 
     A, A 100 , A 200 , A 300 , A 400 , A 500 , A 600  axis 
     C force-bending curve 
     L, L 100 , L 200 , L 300 , L 400 , L 500 , L 600  longitudinal axis 
     M medicament 
     S 1  relaxed state 
     S 2  biased state 
     x abscissa 
     y ordinate 
     x 1 , y 2  coordinates 
     x 2 , y 1  coordinates