Patent Publication Number: US-2021178082-A1

Title: Injection Device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is the national stage entry of International Patent Application No. PCT/EP2018/083182, filed on Nov. 30, 2018, and claims priority to Application No. EP 17306676.2, filed on Dec. 1, 2017, the disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an injection device for a medicament. 
     BACKGROUND 
     Cartridge injection devices, for example cartridge auto-injectors, typically have a sealed cartridge that contains a medicament and a needle that is initially separated from the cartridge. Before use of the injection device the cartridge and needle are combined so that the needle pierces the cartridge. A plunger can then be moved into the cartridge to dispense medicament through the needle for injection into the tissue of a user. 
     SUMMARY 
     According to an aspect of the disclosure, an injection device includes: a housing having an axis, and a needle sleeve that is axially movably within the housing, wherein axial movement of the needle sleeve into the housing is configured to actuate an injection process. The needle sleeve comprises: a first part slidably mounted to the housing, a second part that protrudes from the housing and is rotatably coupled to the first part such that the second part can be rotated relative to the first part about the axis, and a locking mechanism arranged to prevent axial movement of the needle sleeve into the housing until the second part of the needle sleeve has been rotated relative to the first part of the needle sleeve. 
     The locking mechanism may comprise a slot and an engaging member, wherein the engaging member may be disposed in the slot, and wherein the slot may be arranged to prevent axial movement of the needle sleeve until the second part of the needle sleeve has been rotated relative to the first part about the axis. 
     The second part of the needle sleeve may comprise one of the slot and the engaging member, and the housing may comprise the other of the slot and the engaging member. 
     The slot may comprise a radially extending portion and an axially extending portion, and rotation of the needle sleeve relative to the first part may move the engaging member from the radially extending portion into the axially extending portion such that the needle sleeve can move axially into the housing. 
     The second part of the needle sleeve may be rotatable between a first position in which the locking mechanism prevents the needle sleeve from moving axially into the housing, and a second position in which the locking mechanism permits the needle sleeve to move axially into the housing. 
     The injection device may further comprise a reservoir for a medicament and a spring-loaded mechanism for dispensing medicament from the reservoir, and further comprising a catch arranged to hold the spring-loaded mechanism before use of the injection device, and wherein movement of the needle sleeve into the housing may release the catch to actuate the injection process. 
     In some examples, the locking mechanism comprises a slot and a protrusion, and wherein rotation of the second part of the needle sleeve brings the slot and the protrusion into alignment to permit axial movement of the needle sleeve into the housing. 
     The slot may be formed in one of the housing and the second part of the needle sleeve, and the protrusion may be formed in the other of the housing and the second part of the needle sleeve. In one example, the slot is formed in the housing and the protrusion is formed on the second part of the needle sleeve. In another example, the slot is formed in the second part of the needle sleeve and the protrusion is formed on the housing. 
     The protrusion may be adapted to snap into the slot when the slot and protrusion are aligned with each other to prevent further rotation of the needle sleeve. The snap may also create a sound to inform the user that the rotation is complete. 
     The second part of the needle sleeve may comprise a circumferentially extending slot, and the first part of the needle sleeve may comprise a catch that engages the circumferentially extending slot to couple the second part to the first part and permit rotational movement of the second part relative to the second part as the catch moves within the circumferentially extending slot. 
     In some examples, the injection device may further comprise a member arranged to prevent rotation of the first part of the needle sleeve relative to the housing. For example, the member may extend from the housing and engage an axially extending slot or groove in the first part of the needle sleeve, or the member may extend from the first part of the needle sleeve and engage an axially extending slot in the housing. 
     In various examples, one of the first part of the needle sleeve and the housing comprises an axially extending slot, and the other of the first part of the needle sleeve and the housing comprises a protrusion that engages the axially extending slot to prevent rotation of the first part of the needle sleeve relative to the housing. 
     The second part of the needle sleeve may comprise an axially extending slot or a protrusion, and wherein the axially extending slot or the protrusion of the second part may be aligned with the protrusion or axially extending slot, respectively, of the housing after the second part of the needle sleeve has been rotated. In this way, the axially extending slot and protrusion that allows the first part of the needle sleeve to move axially and prevents rotation of the first part of the needle sleeve also serves to prevent axial movement of the second part of the needle sleeve (and therefore the entire needle sleeve) until the second part of the needle sleeve has been rotated. 
     The injection device may further comprise a needle unit having a needle, and a cartridge having a reservoir for a medicament. Prior to use of the injection device the reservoir may be sealed from the needle, and rotation of the second part of the needle sleeve may be configured to move the needle unit such that the needle is placed in fluid communication with the reservoir. 
     Therefore, actuation of the injection process by axial movement of the needle sleeve is prevented at least until the second part of the needle sleeve has been rotated to engage the needle unit and cartridge. 
     The second part of the needle sleeve may comprise an engaging member arranged to move the needle unit in an axial direction when the second part of the needle sleeve is rotated. 
     In some examples, the engaging member may comprise a helical guide arranged to engage a protrusion on the needle unit and move the needle unit as the second part of the needle sleeve is rotated. 
     The engaging member may be arranged to disengage from the needle unit after the second part has been rotated. In this way, the needle sleeve is decoupled from the needle unit and is able to move axially independently of the needle unit to actuate the injection process. 
     The injection device may further comprise a piston disposed in the cartridge and a piston drive mechanism arranged to drive the piston to dispense medicament via the needle. Axial movement of the needle sleeve into the housing may be adapted to actuate the piston drive mechanism. 
     The cartridge may comprise a medicament in the reservoir. 
     According to another aspect of the disclosure, a method of using an injection device that includes a housing and a needle sleeve is provided. The method includes: rotating a part of the needle sleeve relative to the housing to unlock the needle sleeve, and moving the needle sleeve into the housing to actuate an injection process. 
     These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Embodiments of the invention are described, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1A  is a schematic side view of an injection device that embodies the invention, and a removable cap; 
         FIG. 1B  is a schematic side view of the injection device of  FIG. 1A , with the cap removed from the housing; 
         FIG. 2  is a cross-sectional view of an injection device; 
         FIG. 3  is a cross-sectional view of a needle sleeve; 
         FIG. 4  is a cross-sectional view of a needle sleeve; 
         FIGS. 5A to 5C  show a needle unit for use with the injection device; 
         FIGS. 6A to 6C  show steps of operation of the injection device; 
         FIG. 7A  shows an alternative needle sleeve for the injection device; and, 
         FIG. 7B  shows an alternative needle unit for the injection device. 
     
    
    
     DETAILED DESCRIPTION 
     A drug delivery device, as described herein, may be configured to inject a medicament into a patient. For example, delivery could be sub-cutaneous, intra-muscular, or intravenous. Such a device could be operated by a patient or care-giver, such as a nurse or physician, and can include various types of safety syringe, pen-injector, or auto-injector. The device can include a cartridge-based system that requires piercing a sealed ampule before use. Volumes of medicament delivered with these various devices can range from about 0.5 ml to about 2 ml. Yet another device can include a large volume device (“LVD”) or patch pump, configured to adhere to a patient&#39;s skin for a period of time (e.g., about 5, 15, 30, 60, or 120 minutes) to deliver a “large” volume of medicament (typically about 2 ml to about 10 ml). 
     In combination with a specific medicament, the presently described devices may also be customized in order to operate within required specifications. For example, the device may be customized to inject a medicament within a certain time period (e.g., about 3 to about 20 seconds for auto-injectors, and about 10 minutes to about 60 minutes for an LVD). Other specifications can include a low or minimal level of discomfort, or to certain conditions related to human factors, shelf-life, expiry, biocompatibility, environmental considerations, etc. Such variations can arise due to various factors, such as, for example, a drug ranging in viscosity from about 3 cP to about 50 cP. Consequently, a drug delivery device will often include a hollow needle ranging from about 25 to about 31 Gauge in size. Common sizes are 27 and 29 Gauge. 
     The delivery devices described herein can also include one or more automated functions. For example, one or more of combining the needle and cartridge, needle insertion, medicament injection, and needle retraction can be automated. Energy for one or more automation steps can be provided by one or more energy sources. Energy sources can include for example, mechanical, pneumatic, chemical, or electrical energy. Mechanical energy sources can include for example springs, levers, elastomers, or other mechanical mechanisms to store or release energy. One or more energy sources can be combined into a single device. Devices can further include gears, valves, or other mechanisms to convert energy into movement of one or more components of a device. 
     The one or more automated functions of an auto-injector may each be activated via an activation mechanism. Such an activation mechanism can include an actuator, for example, one or more of a button, a lever, a needle sleeve, or other activation component. Activation of an automated function may be a one-step or multi-step process. That is, a user may need to activate one or more activation components in order to cause the automated function. For example, in a one-step process, a user may depress a needle sleeve against their body in order to cause injection of a medicament. Other devices may require a multi-step activation of an automated function. For example, a user may be required to depress a button and retract a needle shield in order to cause an injection. 
     In addition, activation of one automated function may activate one or more subsequent automated functions, thereby forming an activation sequence. For example, activation of a first automated function may activate at least two of combining the needle and cartridge, needle insertion, medicament injection, and needle retraction. Some devices may also require a specific sequence of steps to cause the one or more automated functions to occur. Other devices may operate with a sequence of independent steps. 
     Some delivery devices can include one or more functions of a safety syringe, pen-injector, or auto-injector. For example, a delivery device could include a mechanical energy source configured to automatically inject a medicament (as typically found in an auto-injector) and a dose setting mechanism (as typically found in a pen-injector). 
     According to some embodiments of the present disclosure, an example of a drug delivery device  10  is shown in  FIGS. 1A and 1B . Device  10 , as described above, is configured to inject a medicament into a patient&#39;s body. Device  10  includes a housing  11  which typically contains a cartridge that defines a reservoir containing the medicament to be injected, and the components required to facilitate one or more steps of the delivery process. 
     The device  10  can also include a cap  12  that can be detachably mounted to the housing  11 . Typically, a user must remove cap  12  from housing  11  before device  10  can be operated. 
     As shown, housing  11  is substantially cylindrical and has a substantially constant diameter along the longitudinal axis A-A. The housing  11  has a distal region D and a proximal region P. The term “distal” refers to a location that is relatively closer to a site of injection, and the term “proximal” refers to a location that is relatively further away from the injection site. 
     Device  10  can also include a needle sleeve  19  coupled to housing  11  to permit movement of sleeve  19  relative to housing  11 . For example, sleeve  19  can move in a longitudinal direction parallel to longitudinal axis A-A. Specifically, movement of sleeve  19  in a proximal direction can permit a needle  17  to extend from distal region D of housing  11 . 
     Insertion of needle  17  can occur via several mechanisms. For example, needle  17  may be fixed relative to housing  11  and initially be located within an extended needle sleeve  19 . Proximal movement of sleeve  19  by placing a distal end of sleeve  19  against a patient&#39;s body and moving housing  11  in a distal direction will uncover the distal end of needle  17 . Such relative movement allows the distal end of needle  17  to extend into the patient&#39;s body. Such insertion is termed “manual” insertion as needle  17  is manually inserted via the patient&#39;s manual movement of housing  11  relative to sleeve  19 . 
     Another form of insertion is “automated”, whereby needle  17  moves relative to housing  11 . Such insertion can be triggered by movement of sleeve  19  or by another form of activation, such as, for example, a button  13 . As shown in  FIGS. 1A and 1B , button  13  is located at a proximal end of housing  11 . However, in other embodiments, button  13  could be located on a side of housing  11 . 
     Other manual or automated features can include drug injection or needle retraction, or both. Injection is the process by which a bung or piston  14  is moved from a proximal location to a more distal location within the reservoir of the cartridge  18  in order to force a medicament from the cartridge  18  through needle  17 . In some embodiments, a drive spring (not shown) is under compression before device  10  is activated. A proximal end of the drive spring can be fixed within proximal region P of housing  11 , and a distal end of the drive spring can be configured to apply a compressive force to a proximal surface of piston  14 . Following activation, at least part of the energy stored in the drive spring can be applied to the proximal surface of piston  14 . This compressive force can act on piston  14  to move it in a distal direction. Such distal movement acts to compress the liquid medicament within the cartridge  18 , forcing it out of needle  17 . 
     Following injection, needle  17  can be retracted within sleeve  19  or housing  11 . Retraction can occur when sleeve  19  moves distally as a user removes device  10  from a patient&#39;s body. This can occur as needle  17  remains fixedly located relative to housing  11 . Once a distal end of sleeve  19  has moved past a distal end of needle  17 , and needle  17  is covered, sleeve  19  can be locked. Such locking can include locking any proximal movement of sleeve  19  relative to housing  11 . 
     Another form of needle retraction can occur if needle  17  is moved relative to housing  11 . Such movement can occur if the cartridge  18  within housing  11  is moved in a proximal direction relative to housing  11 . This proximal movement can be achieved by using a retraction spring (not shown), located in distal region D. A compressed retraction spring, when activated, can supply sufficient force to the cartridge  18  to move it in a proximal direction. Following sufficient retraction, any relative movement between needle  17  and housing  11  can be locked with a locking mechanism. In addition, button  13  or other components of device  10  can be locked as required. 
       FIG. 2  illustrates an example injection device  20  having a housing  21 , a cartridge  22 , a needle unit  23 , and a needle sleeve  26 . The injection device  20  further includes a piston  24  and a piston drive mechanism  25 . 
     The cartridge  22  defines a reservoir  28  that contains a medicament and is mounted within the housing  21 . A distal end D of the cartridge  22  is sealed by an end cap  29 . A cartridge mounting portion  30  of the housing  21  supports the cartridge  22 . As illustrated, a part of the cartridge mounting portion  30  is tubular and surrounds the distal end of the cartridge  22 . This tubular part of the cartridge mounting portion  30  has an external surface disposed within the housing  21 . 
     As shown in  FIG. 2 , in an initial condition the proximal end of needle  31  of the needle unit  23  is spaced from the end cap  29  at the distal end of the cartridge  22 . Before or during use of the injection device  20  the needle unit  23  is moved into engagement with the distal end of the cartridge  22  such that the proximal end of needle  31  pierces the end cap  29  of the cartridge  22 . In this way, medicament can be expelled from the reservoir  28  via the needle  31 , as explained further hereinafter. 
     In the initial condition, illustrated in  FIG. 2 , the piston  24  is positioned at a proximal end of the reservoir  28  in the cartridge  22 , and the piston drive mechanism  25  is disposed in the proximal end of the housing  21 . The piston drive mechanism  25  comprises a spring  32 , a plunger  33 , and a catch  34 . The spring  32  is arranged to urge the plunger  33  against the piston  24  and into the reservoir  28  to expel medicament from the reservoir  28  during use. In the initial condition before use, as illustrated, the spring  32  is held in a compressed state by a catch  34 . Specifically, the catch  34  holds the plunger  33 , which holds the spring  32  in a compressed state such that no force is applied to the piston  24 . In this state, the piston drive mechanism  25  is pre-loaded. 
     As explained further hereinafter, the injection device  20  is actuated by an actuator, in this example the needle sleeve  26  that is rotationally and slidably movable within the housing  21  and protrudes from the distal end of the housing  21 . In this way, during use, the needle sleeve  26  is placed against the user&#39;s skin and the injection device  20  is pushed towards the user&#39;s skin while holding the housing  21 , this moves the needle sleeve  26  in a proximal direction, into the housing  21 . 
     The needle sleeve  26  acts to release the catch  34  once the needle sleeve  26  has moved into the housing  21  in a proximal direction. Once the catch  34  is released, the spring  32  urges the plunger  33  against the piston  24  and into the reservoir  28 . 
     As illustrated in  FIG. 2 , the catch  34  may include a tubular element  35  that surrounds the plunger  33  and spring  32 . The tubular element  35  includes protrusions  36  that engage recesses  37  in the plunger  33 , such that in the position illustrated in  FIG. 2  the plunger  33  is prevented from moving in a distal direction by the protrusions  36  and the recesses  37 . 
     As the needle sleeve  26  is moved proximally into the housing  21 , an end of the needle sleeve  26  engages the tubular element  35 , causing the tubular element  35  to rotate about the axis A of the injection device  20 . This rotation causes the protrusions  36  to disengage from the recesses  37 , thereby releasing the plunger  33 , which then moves under the force of the spring  32  into the reservoir  28 . 
     In one example, the end of the needle sleeve  26  that engages the tubular element  35  may comprise a chamfer (i.e. angled edge) that engages a protrusion on the tubular element  35  to cause the rotation. In other examples, the tubular element  35  may comprise a chamfer (i.e. angled edge) that is engaged by a protrusion on the needle sleeve  26  to cause the rotation. 
     In other examples, the catch  34  may comprise arms that include the protrusions that engage the plunger  33 . In this case, the needle sleeve  26  might deflect the arms by lifting them to disengage the protrusions from the recesses, thereby releasing the plunger  33 . 
     A biasing member, for example a spring  42 , may be arranged to act between the housing  21  and the needle sleeve  26  to urge the needle sleeve  26  in a distal direction so that it protrudes from the distal end of the housing  21 . 
     In other examples, movement of the needle sleeve  26  into the housing  21  can actuate the injection process in other ways. For example, movement of the needle sleeve  26  into the housing  21  may move an intermediate component to release the catch  34 . In other examples, movement of the needle sleeve  26  into the housing  21  may close or open an electronic switch which in turn releases the plunger  33 . In still more examples, the plunger  33  may be electronically or pneumatically actuated by an actuator during the injection process, and in such examples movement of the needle sleeve  26  into the housing  21  may activate such an actuator. Therefore, it will be appreciated that movement of the needle sleeve  26  into the housing  21  can actuate the injection process (i.e. movement of the plunger  33  into the reservoir  28 ) in various ways. 
     Before or during use, the needle unit  23  is combined with the cartridge  22  before the catch  34  is released. As explained below, rotating a part of the needle sleeve  26  about the axis A causes one of the needle unit  23  or the cartridge  22  to move axially within the housing  21  so that the needle  31  is placed in fluid communication with the reservoir  28 . A subsequent movement of the needle sleeve  26  in a proximal direction releases the catch  34  so that plunger  33  begins delivery of the medicament via the needle  31 . In various examples described hereinafter, a part of the needle sleeve  26  must be rotated to engage the needle unit  23  and cartridge  22  before the needle sleeve  26  can move axially into the housing  21  to actuate the piston drive mechanism  25 . 
       FIG. 3  illustrates the distal end of the needle sleeve  26  of the injection device  20 . As shown, the needle sleeve  26  has a first part  38  and a second part  39 . The second part  39  of the needle sleeve  26  is rotationally coupled to the end of the first part  38 . As shown, the second part  39  includes a slot  40  and the first part  38  includes a catch  41  that is received in the slot  40 . 
     In the example of  FIG. 3 , the slot  40  is only slightly larger than the catch  41 . In an initial position, the catch  41  is not aligned with the slot  40  and is in a deflected state acting against the inside of the second part  39  of the needle sleeve  36 . Rotation of the second part  39  of the needle sleeve  26  about the axis A moves the catch  41  into alignment with the slot  40  so that the catch  41  snaps into the slot  40  to prevent further rotation. 
     In the example of  FIG. 4 , the slot  40  extends circumferentially about the needle sleeve  26 . The slot  40  thereby allows the second part  39  to rotate relative to the first part  38  about axis A as the catch  41  moves within the slot  40 . The extent of rotation is limited by the length of the slot  40 . In an initial position the catch  41  is at a first end of the slot  40 , and rotation of the second part  39  of the needle sleeve  26  moves the catch  41  to an opposite end of the slot  40 . 
     In the examples of  FIGS. 3 and 4 , there are two slots  40  arranged on opposite sides of the needle sleeve  26 . However, it will be appreciated that only one slot  40  may be provided, or more than two slots  40  may be provided, and the first part  39  will have a corresponding number of catches  41 . 
     As also illustrated in  FIG. 4 , in some examples the second part  39  of the needle sleeve  26  includes an axially extending slot  43 . The axially extending slot  43  moves as the second part  39  of the needle sleeve  26  is rotated. Rotation of the second part  39  of the needle sleeve  26  moves the axially extending slot  43  into alignment with a protrusion (not illustrated) on the housing. In this way, the axially extending slot  43  and protrusion act as a locking mechanism because the protrusion will prevent axial movement of the needle sleeve  26  into the housing  21  until the second part  39  of the needle sleeve  26  has been rotated to align the axially extending slot  43  with the protrusion. 
     Also shown in  FIGS. 3 and 4 , the second part  39  of the needle sleeve  26  also includes an engaging member, in this example a helical guide  44  arranged on an internal surface of the second part  39  of the needle sleeve  26 , extending partially about the internal circumference of the needle sleeve  26 . In examples, the needle sleeve  26  may comprise one or more helical guides  44 , for example two helical guides  44 , or three helical guides  44 . 
     The helical guide  44  acts to move the needle unit  23  into engagement with the cartridge  22  as the second part  39  of the needle sleeve  26  is rotated. 
       FIGS. 5A to 5C  illustrate a needle unit  23  that may be used with the needle sleeve  26  described with reference to  FIGS. 3 and 4 . As shown in  FIG. 5A , the needle unit  23  includes a needle body  45  to which a needle  31  is attached. The needle body  45  includes a recess  46 . The recess  46  is adapted to be positioned over the cartridge mounting portion  30  (see  FIG. 2 ) of the housing  21  (see  FIG. 2 ) when the needle unit  23  is combined with the cartridge  22  (see  FIG. 2 ) during use of the injection device  20 . 
     As shown in  FIG. 5A , and referring to  FIG. 2 , the needle body  45  includes a groove  47  arranged to cooperate with a rail (not illustrated) on the cartridge mounting portion  30  of the housing  21 . The groove  47  is located on the internal surface of the needle body  45 , in the recess  46 . The cooperation of the rail and the groove  47  prevents rotation of the needle unit  23  relative to the housing  21  and cartridge  22 , and guides the needle unit  23  in an axial direction when the helical guide  44  of the second part  39  of the needle sleeve  26  pushes the needle unit  23  onto the cartridge  22 , as explained hereinafter. 
     As shown in  FIGS. 5B and 5C , the outer surface of the needle body  45  includes protrusions  48 . In this example, the external surface of the needle body  45  includes two protrusions  48 , but it will be appreciated that one protrusion  48  is provided for each helical guide  44  on the second part  39  of the needle sleeve  37 . The protrusions  48  are generally circular, but may be other shapes. The protrusions  48  are equally spaced around the circumference of the needle body  45 . 
     Referring to  FIGS. 2 to 5C , the protrusions  48  on the needle body  45  are arranged to engage with the helical guides  44  on the second part  39  of the needle sleeve  26  such that rotation of the second part  39  of the needle sleeve  26  causes axial movement of the needle unit  23  towards the cartridge  22 . In this way, during use of the injection device  20 , the user rotates the second part  39  of the needle sleeve  26  to engage the needle unit  23  with the cartridge  22  and place the needle  31  in fluid communication with the reservoir  28  before the injection process is started. 
       FIGS. 6A to 6C  illustrate the process of combining of the needle unit  23  and cartridge  22 . 
     As shown in  FIG. 6A , and referring also to  FIGS. 3 to 5C , in this initial position the needle unit  23  is spaced from the cartridge  22 . The needle sleeve  26  is in an extended position and covers the needle  31 . In particular, the second part  39  of the needle sleeve  26  protrudes from a distal end of the housing  21 . In this position, the needle unit  23  is held in place by a combination of the engagement between the protrusions  48  and helical guides  44 , the engagement between a proximal end of the needle body  45  and the cartridge mounting portion  30  of the housing  21 , and engagement between the rail (not illustrated) and groove  47 . 
     As the second part  39  of the needle sleeve  26  is rotated the engagement between the helical guides  44  on the second part  39  of the needle sleeve  26  and the protrusions  48  on the needle unit  23  drive the needle unit  23  in an axial direction towards the cartridge  22 . The rail and groove  47  prevent rotation of the needle unit  23  and guide the needle unit  23  onto the cartridge mounting portion  30 . 
     As shown in  FIG. 6A , the proximal end of the needle body  45  includes catches  49  that initially have to be deflected to allow the needle body  45  to move over the cartridge mounting portion  30  of the housing  21 . In the initial position, shown in  FIG. 6A , engagement between the catches  49  and the cartridge mounting portion  30  help to hold the needle unit  23  in position within the injection device  20 . 
       FIG. 6B  shows the injection device  20  after the second part  39  of the needle sleeve  26  has been rotated to move the needle unit  23  into engagement with the cartridge  22 . As shown, the catches  49  on the proximal end of the needle body  45  have engaged with recesses  50  on the cartridge mounting portion  30 , so that the needle unit  23  is secured in place on the cartridge mounting portion  30 . Also, a proximal end of the needle  31  has pierced the end cap  29  of the cartridge  22 , so that the needle  31  is in fluid communication with the reservoir  28 . The needle sleeve  26  remains in an extended position due to the action of the spring  42 . 
     Due to the rotation of the second part  39  of the needle sleeve  26  the helical members  44  have disengaged from the protrusions ( 48 , see  FIGS. 5A to 5C ), so that the needle sleeve  26  is able to move axially independently of the needle unit  23 . 
     Furthermore, as explained previously with reference to  FIGS. 3 to 5C , rotation of the second part  39  of the needle sleeve  26  moves the catches  41  into engagement with the slots  40  ( FIG. 3 ), or moves the catches  41  along the slots  40  ( FIG. 4 ). Rotation of the second part  39  of the needle sleeve  26  has also brought the axially extending slot  43  into line with the protrusion on the housing  21 , so that the needle sleeve  26  is not able to move axially into the housing  21 . 
       FIG. 6C  shows the injection device  20  after the injection device  20  has been pressed against the user&#39;s skin to start the injection process. As illustrated, the needle sleeve  26  has moved proximally into the housing  21 , exposing the needle  31  so that the needle  31  can pierce the user&#39;s skin. Also, as explained previously, proximal movement of the needle sleeve  26  into the housing  21  releases the catch ( 34 , see  FIG. 2 ) of the piston drive mechanism ( 25 , see  FIG. 2 ) to release the plunger ( 33 , see  FIG. 2 ), and the spring ( 32 , see  FIG. 2 ) then drives the piston ( 24 , see  FIG. 2 ) into the cartridge  22  to dispense medicament from the reservoir  28  via the needle  31 . 
     After use, the spring  42  urges the needle sleeve  26  back to an extended position to re-cover the needle  31 . 
       FIGS. 7A and 7B  illustrate an alternative example injection device  20 . In particular  FIG. 7A  illustrates an alternative second part  39  of the needle sleeve  26  and  FIG. 7B  illustrates the needle unit  23  for use with the alternative second part  39 . The second part  39  of the needle sleeve  26  of  FIG. 7A  and needle unit  23  of  FIG. 7B  can be used with the injection device  20  of  FIG. 2 , but in this example, the needle unit  23  is rotationally mounted within the housing  21  and there is no rail and groove  47  as described with reference to previous examples. 
     Referring to  FIGS. 2, 7A and 7B , the needle unit  23  has a needle body  51  having a recess  52 , and an internal thread in the recess  52 . The internal thread is arranged to engage with an external thread on the cartridge mounting portion  30  of the housing  21 , or with an external thread on the cartridge  22 . In an initial position the thread is aligned or partially started, such that on rotation of the needle unit  23  (explained below) the thread moves the needle unit  23  axially into engaged with the cartridge  22 . In this way, the thread acts to guide the needle unit  23  into engagement with the cartridge  22  when the second part  39  of the needle sleeve  26  is rotated. 
     The internal surface of the needle sleeve  26  includes a groove  53 , preferably two grooves  53 . The external surface of the needle body  51  includes a protrusion  54 , preferably two protrusions  54 , that engage with the grooves  53  of the second part  39  of the needle sleeve  26 . In this way, rotating the second part  39  of the needle sleeve  26  in the housing  21  causes rotation of the needle unit  23  within the housing  21 , and the thread moves the needle unit  23  axially into engagement with the cartridge  22  so that the needle  31  is placed in fluid communication with the reservoir  28 . 
     As shown in  FIG. 7B , the needle unit  23  may also include end stops  55  that engage a part of the cartridge mounting portion  30  after the needle unit  23  has been rotated onto the cartridge mounting portion  30  by the thread. Additionally or alternatively, recesses  56  may be provided to engage with catches on the cartridge mounting portion  30 , to secure the needle unit  23  on the cartridge mounting portion  30 . 
     The threaded connection between the needle unit  23  and cartridge mounting portion  30  may have a high pitch, so that comparatively less rotation is needed to achieve the desired axial movement. For example, the rotation may be between 30 and 120 degrees, or about 90 degrees. However, the rotation may be greater than 120 degrees, for example 180 degrees. 
     In various examples, the threaded connection may comprise an external thread on the cartridge mounting portion  30  and an internal thread on the needle unit  23 , or alternatively one of the internal and external threads may be replaced by a protrusion arranged to engage the other thread, so that on rotation of the needle sleeve  23  the protrusion follows the path of the thread and moves the needle unit  23  into engagement with the cartridge  22 . 
     The terms “drug” or “medicament” are used synonymously herein and describe a pharmaceutical formulation containing one or more active pharmaceutical ingredients or pharmaceutically acceptable salts or solvates thereof, and optionally a pharmaceutically acceptable carrier. An active pharmaceutical ingredient (“API”), in the broadest terms, is a chemical structure that has a biological effect on humans or animals. In pharmacology, a drug or medicament is used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. A drug or medicament may be used for a limited duration, or on a regular basis for chronic disorders. 
     As described below, a drug or medicament can include at least one API, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Examples of API may include small molecules having a molecular weight of 500 Da or less; polypeptides, peptides and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes); carbohydrates and polysaccharides; and nucleic acids, double or single stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids may be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more drugs are also contemplated. 
     The drug or medicament may be contained in a primary package or “drug container” adapted for use with a drug delivery device. The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., short- or long-term storage) of one or more drugs. For example, in some instances, the chamber may be designed to store a drug for at least one day (e.g., 1 to at least 30 days). In some instances, the chamber may be designed to store a drug for about 1 month to about 2 years. Storage may occur at room temperature (e.g., about 20° C.), or refrigerated temperatures (e.g., from about −4° C. to about 4° C.). In some instances, the drug container may be or may include a dual-chamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and/or during dispensing into the human or animal body. For example, the two chambers may be configured such that they are in fluid communication with each other (e.g., by way of a conduit between the two chambers) and allow mixing of the two components when desired by a user prior to dispensing. Alternatively or in addition, the two chambers may be configured to allow mixing as the components are being dispensed into the human or animal body. 
     The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and/or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as Rote Liste 2014, for example, without limitation, main groups 12 (anti-diabetic drugs) or 86 (oncology drugs), and Merck Index, 15th edition. 
     Examples of APIs for the treatment and/or prophylaxis of type 1 or type 2 diabetes mellitus or complications associated with type 1 or type 2 diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-1), GLP-1 analogues or GLP-1 receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-4 (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms “analogue” and “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and/or exchanging at least one amino acid residue occurring in the naturally occurring peptide and/or by adding at least one amino acid residue. The added and/or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as “insulin receptor ligands”. In particular, the term “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g. a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide may have been deleted and/or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide. Examples of insulin analogues are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin (insulin glulisine); Lys(B28), Pro(B29) human insulin (insulin lispro); Asp(B28) human insulin (insulin aspart); human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, 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. 
     Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N-tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-gamma-glutamyl)-des(B30) human insulin, B29-N-omega-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin. 
     Examples of GLP-1, GLP-1 analogues and GLP-1 receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-4, Byetta®, Bydureon®, a 39 amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), rExendin-4, CJC-1134-PC, PB-1023, TTP-054, Langlenatide/HM-11260C, 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 examples of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia. Examples of DPP4 inhibitors are Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine. Examples of hormones include hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, and Goserelin. 
     Examples of polysaccharides include a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra-low molecular weight heparin or a derivative thereof, or a sulphated polysaccharide, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and/or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium. An example of a hyaluronic acid derivative is Hylan G-F 20 (Synvisc®), a sodium hyaluronate. 
     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 term antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and/or a dual variable region antibody-like binding protein having cross-over binding region orientation (CODV). 
     The terms “fragment” or “antibody fragment” refer to a polypeptide derived from an antibody polypeptide molecule (e.g., an antibody heavy and/or light chain polypeptide) that does not comprise a full-length antibody polypeptide, but that still comprises at least a portion of a full-length antibody polypeptide that is capable of binding to an antigen. Antibody fragments can comprise a cleaved portion of a full length antibody polypeptide, although the term is not limited to such cleaved fragments. Antibody fragments that are useful in the present invention include, for example, Fab fragments, F(ab′)2 fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, tetraspecific and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), monovalent or multivalent antibody fragments such as bivalent, trivalent, tetravalent and multivalent antibodies, minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art. 
     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. Examples of antibodies are anti PCSK-9 mAb (e.g., Alirocumab), anti IL-6 mAb (e.g., Sarilumab), and anti IL-4 mAb (e.g., Dupilumab). 
     Pharmaceutically acceptable salts of any API described herein are also contemplated for use in a drug or medicament in a drug delivery device. Pharmaceutically acceptable salts are for example acid addition salts and basic salts. 
     Those of skill in the art will understand that modifications (additions and/or removals) of various components of the APIs, formulations, apparatuses, methods, systems and embodiments described herein may be made without departing from the full scope and spirit of the present invention, which encompass such modifications and any and all equivalents thereof.