Abstract:
A component for a drug delivery device comprises a key validation part and a safety part. The key validation part is configured to interact with a key part of another component of the drug delivery device during the assembly of the drug delivery device. In order to support the use of matching components, the safety part is configured to have a different impact if the key part is matched to the key validation part compared to if the key part is not matched to the key validation part.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a U.S. National Phase Application pursuant to 35 U.S.C. §371 of International Application No. PCT/EP2011/072139 filed Dec. 7, 2011, which claims priority to European Patent Application No. 10194420.5 filed Dec. 9, 2010. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to the field of drug delivery devices, and more specifically to the assembly of components of drug delivery devices. 
       BACKGROUND 
       [0003]    A drug delivery device may comprise for instance a delivery and dosing apparatus and an exchangeable cartridge, the cartridge being optionally arranged in addition in a cartridge holder. 
         [0004]    A delivery and dosing apparatus, like an injection pen, can be driven electromechanically by a motor, which drives a transmission to force a liquid substance, for instance a drug or medicament, out of an attached cartridge. 
         [0005]    The cartridge may have a cylindrical body made of glass, plastics, and/or the like. A first end of the cartridge may be closed by a septum which may be pierced by a needle. A second end of the cartridge may be closed by a plunger which is movable inside the cylindrical body of the cartridge to force out the liquid substance or medicament through the needle in the pierced septum. 
         [0006]    The construction of a delivery and dosing apparatus can be adapted specifically to a particular substance that is to be delivered. For example, some delivery and dosing apparatus may be adapted to supply a higher force for use with a liquid substance having a higher viscosity, while another delivery and dosing apparatus may be adapted to supply a smaller force for use with a liquid substance having a smaller viscosity, to deliver the same dosage of substance. Different forces can be achieved by different designs of a motor moving the plunger, or by using plungers of different materials, which results in different amounts of friction. 
         [0007]    Furthermore, a user may use different drug delivery devices, for instance differently colored drug delivery devices, for applying medicaments having a fast or slow efficacy, respectively. 
       SUMMARY 
       [0008]    For these and other reasons, it may be important to ensure that a specific drug delivery device is used with a particular cartridge only. 
         [0009]    A component for a drug delivery device is presented. The component comprises a key validation part configured to interact with a key part of another component of the drug delivery device during an assembly of the component with the other component. The component further comprises a safety part configured to have a different impact if the key part is matched to the key validation part compared to if the key part is not matched to the key validation part. 
         [0010]    Moreover, a drug delivery device is presented, which comprises such a component and such another component. 
         [0011]    The use of a key system for a drug delivery device has the advantage that it enables a large variety of codings. Providing a safety part in combination with a key system has the advantage that the use of matching components can be facilitated. 
         [0012]    Exemplary embodiments of the invention are defined in the appended claims, as well as in the following description. 
         [0013]    In an exemplary embodiment, the component is a drug delivery apparatus, a drug dosing and delivery apparatus, a cartridge configured to comprise a drug, a cartridge holder, or any combination of two of such elements. For instance, a key validation part could belong to a drug delivery apparatus or a drug dosing and delivery apparatus while the key part could belong to a cartridge holder, or vice versa. Furthermore, a key validation part could belong to a drug delivery apparatus or a drug dosing and delivery apparatus while the key part could belong to a cartridge, or vice versa. Furthermore, a key validation part could belong to a cartridge holder while the key part could belong to a cartridge, or vice versa. It could also be provided that three or more elements of a drug delivery device have to be matched to each other to obtain a functional device. This could be achieved by using separate key systems between respective two of the elements, or by splitting up key validation part and/or safety part and/or key part to two of the elements, and/or by adding the safety part to another element than the key validation part, or the like. The drug delivery apparatus or the drug dosing and delivery apparatus may be an injection pen, an infusion pump, an inhaler and/or the like. 
         [0014]    The key system could be distributed for example, but not exclusively, to cartridge and dosing/delivery apparatus, to cartridge holder and dosing/delivery apparatus, or to cartridge and cartridge holder. Its use is thus very flexible. 
         [0015]    A key validation part may comprise for instance one or more pins attached to a respective biasing element. A key part could then be allowed to move each pin against the biasing element force by a distance that depends on the shape of the key part. Only a matched key part would move the pin or pins by a predetermined distance to a release position. The number of possible combinations for dedication increases significantly with the number of employed pins as well as with the range of possible predetermined distances, similarly as in the case of a pin tumbler lock. Such a biasing element could comprise for instance a spring and/or an elastic plastic arm, or the like. 
         [0016]    Alternatively, a key validation part may comprise for instance at least one proximity sensor. Each proximity sensor could be configured to detect whether a key part comes to lie within or at a predetermined distance to the proximity sensor during an assembly of the component with the other component. A hardware circuit or a software-based processor could then determine whether the key part of the other component matches the key validation part by evaluating the output of the at least one proximity sensor. The number of possible combinations for dedication increases significantly with the number of employed proximity sensors as well as with the range of possible predetermined distances. 
         [0017]    The safety part could be implemented in various ways. In an exemplary embodiment, it could comprise a blocking element that enables, as the different impact, a full assembly of the device only if key part and key validation part match. The blocking element could interact directly and mechanically with the key validation part. In this case, a key validation part interacting with a matching key part could move the blocking element from a blocking to a non-blocking position or allow the blocking element to move from a blocking to a non-blocking position. Only in case of such a non-blocking position, a full assembly of the components is possible. Alternatively, the state of a key validation part could be monitored electronically and the blocking element could be controlled electronically. 
         [0018]    In another exemplary embodiment, the safety part could comprise a blocking element that enables, as the different impact, the operation of the drug delivery device only if key part and key validation part match. Enabling the operation could comprise for instance energizing the device or otherwise setting it into a ready to start state. The operation could be enabled electronically, electromagnetically, electromechanically and/or mechanically. 
         [0019]    In another exemplary embodiment, the safety part could further comprise an indicator indicating to a user, as the different impact, that the other component is a matching component, or it could comprise an indicator indicating, as the different impact, the type of one of at least two possible matching other components. The indicator could provide in particular a visual indication, using for instance one or more light emitting diodes, a display or simply an arrow to any of one or more markings. But it could equally provide any other kind of indication, like a haptic indication or an audible indication. 
         [0020]    The key part of the other component could be covered by a cap as long as the other component is not in use for protecting the key part as well as for informing a user about the contained medicament. 
         [0021]    Exemplary embodiments of the invention will be described in more detail in the following with reference to drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a schematic diagram presenting matching components of a drug delivery device according to a first embodiment; 
           [0023]      FIG. 2  is a schematic diagram presenting the matching components of  FIG. 1  in a first interaction state; 
           [0024]      FIG. 3  is a schematic diagram presenting the matching components of  FIG. 1  in a second interaction state; 
           [0025]      FIG. 4  is a schematic diagram presenting non-matching components of a drug delivery device according to the first embodiment in a blocking state; 
           [0026]      FIG. 5  is a schematic diagram presenting components of a drug delivery device according to a second embodiment; 
           [0027]      FIG. 6  is a schematic diagram presenting a key validation part of the drug delivery device of  FIG. 5 ; 
           [0028]      FIG. 7  is a schematic diagram presenting the key validation part of  FIG. 6  when interacting with a matched key part; 
           [0029]      FIG. 8  is a schematic diagram presenting components of a drug delivery device according to a third embodiment; 
           [0030]      FIG. 9  is a schematic diagram presenting details of the drug delivery device of  FIG. 8 ; 
           [0031]      FIG. 10  is a schematic diagram presenting a variation of the drug delivery device of  FIGS. 8 and 9  including an indicator; 
           [0032]      FIG. 11  is a schematic diagram presenting components of a drug delivery device according to a fourth embodiment; and 
           [0033]      FIG. 12  is a schematic diagram presenting components of a drug delivery device according to a fifth embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIGS. 1 to 4  illustrate an assembly of a drug delivery device  100  in accordance with an exemplary first embodiment of the invention. 
         [0035]      FIG. 1  is a schematic diagram, which presents selected components of the drug delivery device  100 . The drug delivery device  100  could be for instance an injection pen, an infusion pump, an inhaler, and/or the like. In an example embodiment, the drug delivery device  100  may be an insulin pen or an injection pen for another drug or medicament. 
         [0036]    The presented components comprise a dosing and delivery apparatus  110  depicted in the upper part of the diagram and a cartridge holder  120  depicted in the lower part of the diagram. The dosing and delivery apparatus  110  and the cartridge holder  120  including a cartridge have to be assembled to obtain a functional drug delivery device  100 . The components can only be assembled, in case a key part of the cartridge holder  120  is matched to a key validation part of the delivery apparatus  110 . 
         [0037]    The dosing and delivery apparatus  110  is shown to have a transparent housing for illustration purposes only. It comprises conventional components of a dosing and delivery apparatus not shown, for example a motor for driving a plunger to force a drug out of a cartridge and a battery for powering the motor, etc. 
         [0038]    The dosing and delivery apparatus  110  comprises in addition at its lower end, facing the cartridge holder  120 , a key validation part. The key validation part includes three springs  112  that are fixed at an upper end to the side wall of the dosing apparatus. The key validation part includes in addition three pins  114 , each being attached to the lower ends of one of the three springs  112 . The dosing apparatus  110  comprises in addition a safety part. The safety part comprises three small rods  116 , each rod being fixed to a respective one of the pins  114  at the side facing the housing of the dosing apparatus  110  such that each rod  116  extends downwards towards the cartridge holder  120  on the right hand side of and slightly closer to the housing of the dosing apparatus  110  than a respective pin  114 . 
         [0039]    The cartridge holder  120  comprises a cartridge with a particular drug, like a particular insulin product. The cartridge holder  120  further comprises at the upper end facing the dosing apparatus  110  key elements  122  and return elements  124 . The key elements  122  form a key part of the cartridge holder  120 . They comprise by way of example three pins extending in direction of the dosing apparatus  110 . The height of the key elements  122  is specific to a particular type of drug in the cartridge. They may be arranged on top of a ring-structure  126  at the upper end of the cartridge holder  120  that is flush with the inner wall of the cartridge holder  120  but recessed to the outer wall of the cartridge holder  120 . The key elements  122  have the same radial distance to a center of the cartridge holder  120  as the pins  114 , when cartridge holder  120  and dosing and delivering apparatus  110  are aligned. The return elements  124  have the form of a right-angled trapezoid with the short one of the parallel sides facing upwards and the slope running downwards to the left. They are arranged on top of the outer wall of the cartridge holder  120  and have the same height as ring-structure  126 . The upper, short parallel side of the return elements  124  is moreover horizontally aligned with the bottom of a respective one of the key element  122 . The return elements  124  have the same radial distance to a center of the cartridge holder  120  as the rods  116 , when cartridge holder  120  and dosing and delivering apparatus  110  are aligned. 
         [0040]    As indicated by arrow  130 , the upper part of the cartridge holder  120  first has to be approached to the lower part of the dosing delivery apparatus  110 . Some complementary alignment elements at dosing and delivery apparatus  110  and cartridge holder  120 , not shown, are provided for ensuring alignment. 
         [0041]      FIG. 2  is a schematic diagram, which presents the same selected components of the drug delivery device  100  as  FIG. 1 . Same elements are denoted with same reference signs. 
         [0042]    In this assembly stage, the upper part of the cartridge holder  120  has been approached as far as possible to the lower part of the dosing and delivery apparatus  110 . As can be seen, the pins  114  of the dosing and delivery apparatus  110  are in contact with the key elements  122  of the cartridge holder  120 , and the pins  114  have been pushed upwards compressing the springs  112 . Since the rods  116  are connected to the pins  114 , they have been moved upwards by the same amount as the pins  114 . 
         [0043]    Since the key elements  122  are matched to the pins  114  of the dosing apparatus  110 , the bottom of all rods  116  stays above the return elements  124  of the cartridge holder  120 . 
         [0044]    As indicated by arrow  140 , the cartridge holder  120  now has to be rotated in a counter clockwise rotation, in order to complete the assembly of the drug delivery device  100 . 
         [0045]      FIG. 3  is a schematic diagram, which presents again the same selected components of the drug delivery device  100  as  FIG. 1 . Same elements are denoted with same reference signs. In the depicted assembly stage, the return features  124  of the cartridge holder  10  are being rotated past the rods  116  of the dosing apparatus  110 , as indicated by arrows  150 . In this process, the cartridge holder  120  is screwed in to the dosing apparatus  110 , or otherwise connected. Any kind of standard assembly process or connections could be used to this end, including threads, luer lock, etc. 
         [0046]    As soon as the rods  116  get into the region of the slope of the return features  114 , the springs  112  begin to expand again, as shown in  FIG. 3 . The slope of the return features  114  ensures that a reverse rotation is enabled for disconnecting the components  110 ,  120  again. 
         [0047]      FIG. 4  is a schematic diagram, which presents again similar selected components of a drug delivery device  100  as  FIG. 1 . Corresponding elements are denoted with same reference signs. In this case, however, the key elements  122  of the cartridge holder  120  are not matched to the key validation part  112 ,  114  of the dosing and delivery apparatus  110 . 
         [0048]    When approaching the cartridge holder  120  to the dosing apparatus  110  for assembly, the two leftmost pins  114  are not pushed upwards sufficiently by the associated key element  122  to ensure that also the attached rods  116  are pushed upwards sufficiently to stay above the associated return features  124  of the cartridge holder  120 . Instead, the two leftmost rods  116  overlap with the two leftmost return features  124 , extending downwards on the right hand side of these return features  124 . 
         [0049]    As a result, the two leftmost rods  116  act as blocking elements, since they prevent that the cartridge holder  120  can be screwed into the dosing and delivery apparatus  110 , as indicated by arrows  160 . 
         [0050]    It is to be understood that instead of three pins  114  and associated key elements  122 , any other number could be used as well. 
         [0051]      FIGS. 5 to 7  illustrate an assembly of a drug delivery device  200  in accordance with an exemplary second embodiment of the invention. 
         [0052]      FIG. 5  is a schematic diagram, which presents selected components of the drug delivery device  200 . The drug delivery device  200  could be again an injection pen, an infusion pump, an inhaler, and/or the like. 
         [0053]    The presented components comprise a dosing and delivery apparatus  210  depicted in the upper part of the diagram and a cartridge holder  220  depicted in the lower part of the diagram. The dosing and delivery apparatus  210  and the cartridge holder  220  including a cartridge have to be assembled to obtain a functional drug delivery device  200 . The components can only be assembled, in case a key part of the cartridge holder  220  is matched to a key validation part of the dosing and delivery apparatus  210 . 
         [0054]    The dosing and delivery apparatus  210  comprises again conventional components of a dosing apparatus not shown. The dosing and delivery apparatus  210  comprises in addition a number of spring elements  212 , for instance three, arranged one above the other and extending horizontally. They can be fixed for instance to the wall of the dosing and delivery apparatus  210 . A pin element  214  is attached to a free end of each of the spring elements  212 . The combination of spring elements  212  and pin elements  214  form the key validation part of the dosing and delivery apparatus  210 . The dosing and delivery apparatus  210  further comprises a blocking element  216  and a spring element  218  acting on the blocking element  216 . The spring element  218  could equally be attached to the wall of the dosing and delivery apparatus  210 , but at an angular distance to the spring elements  212 . The combination of blocking element  216  and spring element  218  forms a safety part of the dosing and delivery apparatus  210 . As can be seen, the spring element  218  is arranged above the elements of the key validation part, while the blocking element  216  is a beam that extends downwards, starting from the height of the spring element  218 , over the entire height of the key validation part. 
         [0055]    The cartridge holder  220  comprises a key part  222  interacting with the key validation part of the dosing and delivery apparatus  210  when the upper part of the cartridge holder  220  is brought together with the lower part of the dosing apparatus  210  such that the key part  222  enters the dosing apparatus  210 . 
         [0056]    The interaction between the key part  222  and the key validation part  212 ,  214  will now be described in more detail with reference to  FIGS. 6 and 7 . 
         [0057]      FIG. 6  is a schematic diagram of a top view on one pair of a spring element  212  and a pin element  214  of the key validation part of the dosing and delivery apparatus  210  and on the blocking element  222  and the spring element  218  of the dosing and delivery apparatus  210 . 
         [0058]    Each pin element  214  has a short, pointed part for interacting with a key part and in parallel a longer rectangular part including a recess  215  for interacting with the blocking element  216 . There is a short connection between the pointed part and the rectangular part where the pin element  214  is connected to the spring element  212 . 
         [0059]    While no key part has been entered into the dosing and delivery apparatus  210 , the spring element  212  is decompressed. As a result, the blocking element  216  is pushed back by the rectangular part of the pin element  214  so that the spring element  218  is compressed. 
         [0060]    If a key part  222  of a cartridge holder  220  is entered, as shown in  FIG. 7 , each pin  214  will be pushed towards the housing of the dosing and delivery apparatus  210  so that the associated spring element  212  is compressed. As a result, the recess  215  of each pin elements  214  is moved in direction of the housing of the dosing and delivery apparatus  210  as well. 
         [0061]    If the key part  222  of cartridge holder  220  is matched to the key validation part of dosing apparatus  210 , each of the pin elements  214  is pushed exactly by an amount that ensures that the associated recess  215  aligns with the blocking element  216 . When the recesses of all pin elements  214  are aligned with the blocking element  216  and thus to each other, the compressed spring element  218  pushes the blocking element  216  into the series of recesses  215 . As a result, the blocking element  216  clears the passage for the key part  222 , so that a user is able to screw the cartridge holder  220  into the dosing and delivery apparatus  210 . 
         [0062]    It is to be understood that some mechanism may be provided to retract the blocking element  216  from the recesses  215  again, when the cartridge holder  220  and thus the key part  222  are removed again from the dosing and delivery apparatus  210 . For instance, the left hand side of the blocking element  216  in the top view of  FIGS. 6 and 7  could be slanted such that the upper side of the blocking element  216  is smaller than the lower side of the blocking element  216 , which is attached to the spring  218 . Alternatively or in addition, the right wall of the recess  215  in the top view of  FIGS. 6 and 7  could be slanted in a complementary manner. When retracting the key part  222 , the force of the spring elements  212  pushing the pin elements  214  forward could then push the blocking element  216  out of the recess  215 , against the force applied by the spring element  218 . 
         [0063]    If the key part  222  of the cartridge holder  220  is not matched to the key validation part of the dosing and delivery apparatus  210 , at least one of the pin elements  214  will be pushed by the key part  222  by an amount that does not ensure that the associated recess  215  aligns with the blocking element  216 . In this case, the compressed spring element  218  is not able to move the blocking element  216 . As a result, the blocking element  216  continues blocking the passage of the key part  22  and prevents thereby that the cartridge holder  220  is screwed in to the dosing and delivery apparatus  210 . 
         [0064]      FIGS. 8 to 10  illustrate an assembly of a drug delivery device  300  in accordance with an exemplary third embodiment of the invention. 
         [0065]      FIG. 8  is a schematic diagram of a drug delivery device  300  that is about to be assembled. The drug delivery device  300  comprises a delivery apparatus  310  depicted in the lower part of the diagram, and a cartridge holder  320  including a cartridge  330  depicted in the upper part of the diagram. 
         [0066]    The delivery apparatus  310  may comprise again conventional components of a delivery apparatus not shown. The delivery apparatus  310  comprises in addition a key validation part. The delivery apparatus  310  further comprises a lock/unlock ring  317 . The lock/unlock ring  317  surrounds the upper end of the dosing apparatus  310  and is fixed to the housing of the dosing apparatus  310  such that it can be turned while staying at the same height. The lock/unlock ring  317  comprises at its inner surface a safety part and a retainer part, both extending into the actual delivery apparatus  310 , for example through an opening in the housing of the delivery apparatus  310 . 
         [0067]    The cartridge holder  320  comprises a key part  322  that extends into the delivery apparatus  310  when the drug delivery device  300  is assembled. In addition, the cartridge holder  320  comprises a retainer counterpart  324  that equally extends into the delivery apparatus  310  when the drug delivery device  300  is assembled. A small portion of key part  322  and retainer counterpart  324  are still visible in  FIG. 8 , since cartridge holder  320  and dosing apparatus  310  have not yet been pushed together completely as required for a complete assembly. 
         [0068]      FIG. 9  is a schematic diagram illustrating the interaction between key part, key validation part, safety part, retainer part and retainer counterpart of the drug delivery device  300  of  FIG. 8 . 
         [0069]    The key part  322  and the retainer counterpart  324  are attached to the cartridge holder  320  and extend into the delivery apparatus  310 , as mentioned before. The right hand side of the key part  322  has a profiled surface structure, which is specific to the cartridge holder  320  and thus indirectly to the cartridge  330  and the contained medicament. The retainer counterpart  324  can simply be a vertical rod, which is bended at its lower end towards the left hand side. 
         [0070]    The key validation part comprises a number of spring elements  312 , for instance three, that are attached one above the other to the housing of the delivery apparatus  310  and extend vertically to the left hand side. Moreover, the key validation part comprises pin elements  314  attached to the free end of a respective spring element  312  and extending still further to the left hand side. Each of the pin elements  314  has a recess  315  passing through the pin element  314  from top to bottom, for instance in the form of a circular hole. The pin elements  314  may have different lengths and the recess  315  of each pin element  314  may be provided at a different location. Finally, the key validation part may have a guiding element  316 , which is equally fixed to the housing of the delivery apparatus  310 . 
         [0071]    The safety part is attached to the inner surface of the lock/unlock ring  317  and comprises a flexible arm  318  as a blocking element as well as a rigid arm  319  as a retainer part. 
         [0072]    When cartridge holder  320  and delivery apparatus  310  are brought together, the key part  322  pushes the pin elements  314  in direction of the housing of the delivery apparatus  310 , compressing the spring elements  312 . The amount of movement of each pin elements  314  is determined by the profile of the key part  322  at the height of the pin element  314  when cartridge holder  320  and delivery apparatus  310  have been brought together completely. 
         [0073]    In case the key part  322  is matched to the key validation part, the recesses  315  of the pin elements  314  align to form a passageway, as shown in  FIG. 9 . As a result, the flexible arm  318  can be pushed through the formed passageway, guided by the guiding element  316 , by turning the lock/unlock ring  317  counterclockwise. As the flexible arm  318  is pushed through the passageway, the rigid arm  319  will be moved by the same amount in direction of the retainer counterpart  324  until it overlaps with the bend portion of the retainer counterpart  324 . As a result, the cartridge container  320  is securely fixed to the delivery apparatus  310 . The fixing can be lifted again simply by turning the lock/unlock ring  317  in a clockwise rotation. 
         [0074]    In case the key part  322  is not matched to the key validation part, in contrast, the recesses  315  of the pin elements  314  will not align and no passageway is formed. As a result, the lock/unlock ring  317  cannot be turned counterclockwise as far as with a matching key part  322 , since the flexible arm  318  will be stopped at the latest by the uppermost pin element  314 . Consequently, the rigid arm  319  cannot be moved sufficiently to overlap with the bend portion of the retainer counterpart  324  either, and the cartridge container  320  cannot be securely fixed to the delivery apparatus  310 . 
         [0075]      FIG. 10  is a schematic diagram presenting a variation of or a supplement to the third embodiment presented with reference to  FIGS. 8 and 9 . Like elements are denoted with the same reference signs. 
         [0076]    This variation includes as well a cartridge holder with a key part  322 , and a delivery apparatus with a key validation part including spring elements  312  and pin elements  314  with a respective recess  315 , and with a safety part including a flexible arm  318  fixed to a lock/unlock ring  317  of the delivery apparatus  310 . The other elements described for the embodiment of  FIGS. 8 and 9  may or may not be included as well. 
         [0077]    In this variation, the lock/unlock ring  317  comprises in addition an indicator  341  that is visible to a user. The indicator  341  could be simply a triangular form attached to the bottom of the lock/unlock ring  317 , with one corner pointing downwards similarly as an arrow. Moreover, the delivery assembly comprises a marking on its housing beneath the lock/unlock ring  317 . The marking could include for example the name of a first medicament “Drug A” and the name of a second medicament “Drug B”. 
         [0078]    Now, a key part  322  of a first type of cartridge holder may align the recesses  315  of the pin elements  314  such that the flexible arm  318  may be pushed through all of the pin elements  314 , similarly as shown in  FIG. 9 . In this case, the indicator  341  comes to stop above the marking “Drug B”. A key part  322  of a second type of cartridge holder, in contrast, may align the recesses  315  of the pin elements  314  such that the flexible arm  318  may be pushed through all but the highest one of the pin elements  314 , as shown in  FIG. 10 . That is, the lock/unlock ring  317  cannot be turned quite as far as with the key part  322  of the first type of cartridge holder. In this case, the indicator  341  comes to stop above the marking “Drug A”. If a retainer counterpart is provided in this variation as in  FIG. 9 , the bended part could be sufficiently long so that a secure fix can be achieved with both types of key parts. 
         [0079]      FIG. 11  illustrates an assembly of a drug delivery device  400  in accordance with an exemplary fourth embodiment of the invention.  FIG. 11  is a schematic diagram, which presents selected components of the drug delivery device  400 . The drug delivery device  400  could be for instance an injection pen. 
         [0080]    The presented components belong to a dosing and delivery apparatus  410  and a cartridge  420 , which have to be assembled to obtain a functional drug delivery device  400 . 
         [0081]    The dosing and delivery apparatus  410  comprises again conventional components of a delivery apparatus not shown. The dosing and delivery apparatus  410  comprises in addition a key validation part. The key validation part includes five springs  412  that are fixed within the dosing and delivery apparatus  410 . The key validation part includes in addition five pins  413 , each being attached to the free ends of one of the five springs  412 . Each of the pins  413  comprises a conductive element  414  somewhere in the middle. Springs  412  and pins  413  extend horizontally in the depicted arrangement. The dosing and delivery apparatus  410  comprises in addition a safety part. The safety part comprises an electrical circuit  415 . The electrical circuit  415  includes a power source  416 , a conductive element  417  and a sensor  418 . The power source  416  could be a battery, for instance the same battery that is used for driving a motor of the dosing and delivery apparatus  410 . The conductive element  417  is made of a conductive material that is interrupted at five positions by a non-conductive material or a less conductive material. The conductive element  417  is arranged to extend vertically to the horizontally arranged pins  413 . Each of the areas made of non-conductive material is in close contact with one of the pins  413 , the breadth of the pins  413  overlapping the areas made of non-conductive material. 
         [0082]    The cartridge  420  may be used by itself or it may be included in a cartridge holder, not shown. The upper end of the cartridge  420  is surrounded by five fixed key rings  422 . The inner diameter of each of the key rings  422  is basically the same as the outer diameter of the cartridge cylinder. The outer diameters of the key rings  422  may differ from each other to enable a large number of different codings for different types of cartridges. Using key rings  422  has the effect that the cartridge  420  could be inserted into a dosing and delivery apparatus  410  with any rotational angle. It is to be understood, though, that the cartridge could equally be provided for example with pins attached to one side of the cartridge only, in particular if guidance elements are provided which ensure that the cartridge  420  can be inserted into the dosing and delivery apparatus  410  with a single rotational orientation only. 
         [0083]    When the cartridge  420  is inserted into the dosing and delivery apparatus  410 , each key ring  422  pushes back one of the pins  413 , compressing the associated spring  412 . If the outer diameters of the key rings  422  are matched to the pins  413 , the conductive areas  414  of the five pins  413  align exactly on top of the five non-conductive areas of the conductive element  417 . As a result, the electrical circuit  415  is closed. The pins  413  thus act as a kind of a switch for the electrical circuit  415 . The sensor  418  will sense the closing of the electrical circuit  415  and send a signal indicating that a correct cartridge has been inserted to a control part of the dosing and delivery device  410 , not shown. Only upon receipt of such a signal, the control part will enable an activation of the drug delivery device  400 , for example an activation of a motor, a dose selection function, and/or any other functional part used to deliver the drug or medicament of the drug delivery device  400 . 
         [0084]    Alternatively or in addition, the safety part could comprise an indicator. Such an indicator could be for instance a light-emitting diode and replace the sensor  418  in electrical circuit  415 . A closed circuit  415  could then power up the light emitting diode to indicate to a user that a correct cartridge has been inserted. The indicator could also be provided externally to the electric circuit  15  and be caused by sensor  418  to inform a user whenever a correct cartridge has been inserted. 
         [0085]    In another variation, the dosing and delivery apparatus  410  could support a plurality of cartridge types. In this case, at least one of the pins  413  could be provided with at least two conductive parts. If these conductive parts have furthermore different electric properties, such as different resistances, the sensor  418  could detect which type of cartridge has been inserted and indicate so by activating one of different light emitting diodes associated to different drugs or by providing an indication on a display of the dosing apparatus  410 . In another variation, the closed electrical circuit  415  could power up a normally closed locking pin to enable a complete assembly of the drug delivery device in the case of matched key rings. In yet another variation, at least a part of the electrical circuit  415  could be integrated in a cartridge holder. It is further to be understood that any other number of key rings  422  and associated pins  413  could be used. 
         [0086]      FIG. 12  illustrates an assembly of a drug delivery device  500  in accordance with an exemplary fifth embodiment of the invention. The arrangement is similar as in the fourth embodiment described with reference to  FIG. 11 . 
         [0087]    A cartridge  520  may be provided again with a number of key rings  524 , for instance five, or similar coding means. 
         [0088]    The dosing and delivery apparatus  510  comprises in this case a key validation part including a series of proximity sensors or proximity switches  512  and a processor  516 , though. Each proximity switch  512  is able to detect the presence of an element in a sensing distance  514 . The processor  516  is configured to receive and evaluate the signals provided by the proximity switch  512 . The dosing and delivery apparatus  510  comprises in addition a safety part  518  linked to the processor  516 . The safety part  518  may comprise indicator means and/or blocking means. 
         [0089]    If the cartridge  520  is inserted into the dosing and delivery apparatus  510 , the proximity switches  512  will emit a signal ‘10100’, where a ‘1’ stands for ‘on’ and a ‘0’ for ‘off’ of a respective one of the five switches  512 , since the first and third ones of the key rings  522 , counted from the top, extends into the sensing distance  514 , while the second, fourth and fifth ones of the key rings  522  do not extend into the sensing distance  514 . In an alternative embodiment, the proximity switches  512  are sensors, each sensor emitting a signal indicative of a sensed distance  514  of a key ring  522 . The processor  516  may evaluate whether each ring  522  is within or at a predefined distance, or whether each ring is within a predefined distance range. 
         [0090]    The processor  516  may determine based on these signals whether the inserted cartridge  520  is of a supported type, and possibly in addition determine the type of the inserted cartridge  520  in case a plurality of different cartridge types using different key rings  522  is supported. The result of the evaluation by the processor  516  may be used for causing the safety part  518  to indicate that a correct cartridge is being used, to indicate which type of cartridge is being used, to block or enable a further assembly of the drug delivery device  500 , and/or to prevent or enable an operation of the drug delivery device  500 , similarly as described for the fourth embodiment. 
         [0091]    It is to be understood that the presented embodiments can be varied in many ways within the scope of the appended claims. 
         [0092]    In particular, the arrangement of key part, key validation part and safety part could be distributed differently to components of a drug delivery device, for example to cartridge, cartridge holder and delivery apparatus. Furthermore, any mentioned spring element could be replaced by some other type of biasing element. Moreover, the features of any presented embodiment can be combined with the features of any other presented embodiment.