Patent Publication Number: US-10781959-B2

Title: Coded cartridge holder and fastener enabled by cartridge size

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 13/522,491, filed Dec. 4, 2012, which is a U.S. National Phase Application pursuant to 35 U.S.C. § 371 of International Application No. PCT/EP2011/050799 filed Jan. 21, 2011, which claims priority to U.S. Provisional Patent Application No. 60/297,611 filed on Jan. 22, 2010 and also claims priority to European Patent Application No. 10160873.5 filed on Apr. 23, 2010. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
    
    
     FIELD OF INVENTION 
     The present disclosure is generally directed to reservoirs, particularly reservoirs containing a medicament. More particularly, the present disclosure is generally directed to a coded cartridge holder and a fastener enabled by a cartridge intended for use with the cartridge holder, for example a cartridge having the correct size, so as to prevent unwanted reservoir cross use. As just one example, such medicament reservoirs may comprise an ampoule, a cartridge, a vial, or a pouch, and may be used with a medical delivery device. Exemplary medical delivery devices include, but are not limited to syringes, pen type syringes, pumps, inhalers, or other similar injection or infusing devices that require at least one reservoir containing at least one medicament. 
     BACKGROUND 
     Medicament reservoirs such as ampoules, cartridges, or vials are generally known. Such reservoirs are especially used for medicaments that may be self administered by a patient. For example, with respect to insulin, a patient suffering from diabetes may require a certain amount of insulin to either be injected via a pen type injection syringe or infused via a pump. With respect to certain known reusable pen type drug delivery devices, a patient loads a cartridge containing the insulin into a proximal end of a cartridge holder. After the cartridge has been correctly loaded, the user may then be called upon to select a dose of medicament. Multiple doses may be dosed from the cartridge. Where the drug delivery device comprises a reusable device, once the cartridge is empty, the cartridge housing is disconnected from the drug delivery device and the empty cartridge is removed and replaced with a new cartridge. Most suppliers of such cartridges recommend that the user disposes of the empty cartridges properly. Where the drug delivery device comprises a disposable device, once the cartridge is empty, the user is recommended to dispose of the entire device. 
     Such known self administration systems requiring the removal and reloading of empty cartridges have certain limitations. For example, in certain generally known systems, a user simply loads a new cartridge into the delivery system without the drug delivery device or without the cartridge having any mechanism of preventing cross use of an incorrect cartridge. That is, the drug delivery device does not have a mechanism for determining if the medicament contained in the cartridge is indeed the correct type of medicament to be administered by the patient. Alternatively, certain known drug delivery devices do not present a mechanism for determining if the correct type of medicament within the cartridge should be used with that particular drug delivery system. This potential problem could be exacerbated given that certain elderly patients, such as those suffering from diabetes, may have limited manual dexterity. Identifying an incorrect medicament is quite important, since the administration of a potentially incorrect dose of a medicament such as a short acting insulin in lieu of a long acting insulin could result in injury or even death. 
     Some drug delivery devices or systems may use a color coding scheme to assist a user or care giver in selecting the correct cartridge to be used with a drug delivery device. However, such color coding schemes pose challenges to certain users, especially those users suffering from poor eyesight or color blindness: a situation that can be quite prevalent in patients suffering from diabetes. 
     As such, there is a growing desire from users, health care providers, care givers, regulatory entities, and medical device suppliers to reduce the potential risk of a user loading an incorrect drug type into a drug delivery device. There is also, therefore, a desire to reduce the risk of dispensing an incorrect medicament (or the wrong concentration of the medicament) from such a drug delivery device. 
     There is, therefore, a general need to physically dedicate or mechanically code a cartridge to its drug type and design a drug delivery device, for example an injection device, that only accepts or works with the dedication or coded features provided on or with the cartridge so as to prevent unwanted cartridge cross use. Similarly, there is also a general need for a dedicated cartridge that allows the medical delivery device to be used with only an authorized cartridge containing a specific medicament while also preventing undesired cartridge cross use. 
     There is also a general need to provide a dedicated cartridge that is difficult to tamper with so that the cartridge may not be compromised in that the cartridge can be used with an unauthorized drug or drug delivery device. Because such cartridges may be difficult to tamper with, they may also reduce the risk of counterfeiting: i.e., making it more difficult for counterfeiters to provide unregulated counterfeit medicament carrying products. 
     The problem to be solved by the present invention is to provide a drug reservoir and a drug delivery system where the safety for the user is improved. 
     SUMMARY 
     For purposes of the present disclosure, a cartridge dimension, such as length or diameter, may indicate a particular drug or medicament. A cartridge holder may be coupled to (e.g., inserted into) a drug delivery device. If the cartridge or drug is correct for the device (i.e., the cartridge has the correct dimension), the cartridge holder may be properly secured, i.e., fastened to the drug delivery device. In particular, a fastening mechanism may be enabled or is allowed to function properly. The fastening mechanism may be enabled by the cartridge and, in particular, by a mechanical interaction of the cartridge with the cartridge holder or a part of the drug delivery device, to fasten the cartridge holder to the device. On the other hand, if the cartridge or drug is not correct for the drug delivery device (i.e., the cartridge has an incorrect dimension), the fastening mechanism may be disabled from functioning properly. Thereby, the cartridge holder cannot be properly secured to the device. Thus, this system ensures that the appropriate cartridge can only be used with the correct drug delivery device. 
     According to one aspect, a cartridge holder for use with a drug delivery device, for example a pen type drug delivery device is provided. The cartridge holder may comprise an inner bore being configured to receive a cartridge, for example a glass cartridge. The cartridge holder may further comprise a fastening mechanism configured to fasten the cartridge holder to the drug delivery device. The fastening mechanism may comprise a first fastener configured to engage with a second fastener of the drug delivery device for fastening the cartridge holder to the drug delivery device. As examples, the first fastener may comprise a pin, a tab or a groove. The second fastener may comprise a corresponding feature engageable with the first fastener. The fastening mechanism may comprise any means suitable for securely fastening the cartridge holder to the drug delivery device. 
     The fastening mechanism may be configured such that an elastic deformation of at least one of part of the drug delivery device and the cartridge holder by mechanical interaction with a cartridge accommodated in the cartridge holder enables fastening the cartridge holder to the drug delivery device. In particular, the fastening mechanism may be configured such that only if a cartridge intended for use with the drug delivery device and, in particular, a cartridge having the correct dimension, for example the correct length or diameter, is accommodated in the cartridge holder, fastening is enabled. Accordingly, a fastening of the cartridge holder to the drug delivery device may be disabled by a cartridge having an incorrect dimension, for example an incorrect length or diameter. 
     The cartridge holder may be configured such that an accommodated cartridge acts on the fastening mechanism of the cartridge holder. In particular, the cartridge may act on a part of the fastening mechanism and thereby elastically deform the part of the fastening mechanism. As an example, the cartridge may act with its proximal end on the fastening mechanism. The elastic deformation may result in the correct configuration of the fastening mechanism, and, in particular, of the first fastener such that an engagement of the first fastener with a corresponding second fastener of the device is enabled. As examples, the fastening mechanism may comprise an inwardly facing sprung arm or an elliptical ring comprising the first fastener. By a deformation of the sprung arm or the elliptical ring, the first fastener may be pushed radially outwards by a portion of a cartridge such that the fastener is in the correct position for engagement with a second fastener of the drug deliver device. 
     The cartridge holder may comprise a first blocking feature configured for engagement with a second blocking feature of the drug delivery device, if a correct cartridge is accommodated in the cartridge holder. As examples, the first blocking feature may comprise a notch or a pin. The second blocking feature may have a corresponding design. On an elastic deformation of a part of the drug delivery device the first blocking feature may be enabled to engage with the second blocking feature, thereby enabling a fastening of the cartridge holder to the drug delivery device. In particular, the drug delivery device may comprise a cartridge detector, wherein on elastic deformation of a part of the cartridge detector by a correct cartridge, fastening of the cartridge holder to the drug delivery device is enabled. Here, a proximal end of the cartridge may act on the cartridge detector. The cartridge detector may comprise a resilient member, for example a spring, which is elastically deformed by the cartridge. The cartridge detector may comprise the second blocking feature. By an elastic deformation of a part of the cartridge detector by a correct cartridge, the second blocking feature may get into a correct position, for example a correct axial position, to engage with the first blocking feature. If an incorrect cartridge is accommodated in the cartridge holder, the second blocking feature may not get into the correct position such that an engagement with the first blocking feature is disabled. In an alternative embodiment, the cartridge may deform a part of the cartridge holder to enable engagement of the first and second blocking feature. 
     According to a specific embodiment, a cartridge holder for use with a drug delivery device is provided. The cartridge holder comprises an inner bore being configured to receive a cartridge and a fastening mechanism configured to fasten the cartridge holder to the drug delivery device. The fastening mechanism is configured such that an elastic deformation of at least one of part of the drug delivery device and the cartridge holder by mechanical interaction with a cartridge accommodated in the cartridge holder enables fastening the cartridge holder to the drug delivery device. 
     According to a specific embodiment, a cartridge holder for use with a drug delivery device is provided. The cartridge holder comprises an inner bore being configured to receive a cartridge and a fastening mechanism enabled by a proximal end of the cartridge. The fastening mechanism comprises at least one inwardly facing sprung arm. 
     According to a further specific embodiment, a cartridge holder for use with a drug delivery device is provided. The cartridge holder comprises an inner bore being configured to receive a cartridge and a fastening mechanism enabled by a proximal end of the cartridge. In particular, the fastening mechanism may be enabled by a mechanical interaction of the proximal end of the cartridge and the fastening mechanism. The fastening mechanism may include an elliptical ring. 
     According to a further aspect, a drug delivery device for use with a cartridge holder is provided. The cartridge holder may accommodate a cartridge and may be secured to the drug delivery device. The drug delivery device may include an inner bore configured to receive the cartridge holder. The cartridge holder may have any of the structural or functional properties as described above. In particular, the cartridge holder may comprise a fastening mechanism. The cartridge holder may further comprise a first blocking feature. A cartridge detector may be located within an inner bore of the delivery device, and may include a second blocking feature for engagement with the first blocking feature when the cartridge acts on the cartridge detector. The drug delivery device may comprise a fastening mechanism configured to interact with a fastening mechanism of the cartridge holder to fasten the cartridge holder to the drug delivery device. Here, a fastening may only be enabled when the second blocking feature engages the first blocking feature. 
     According to a specific embodiment, a drug delivery device for use with a cartridge holder is provided. The cartridge holder may have any functional and structural properties as described in this disclosure. The cartridge holder accommodates a cartridge and is configured to be attached to the drug delivery device. The drug delivery device comprises a device fastening mechanism configured to interact with the fastening mechanism of the cartridge holder to fasten the cartridge holder to the drug delivery device when the cartridge holder accommodates a correct cartridge. 
     According to a specific embodiment a drug delivery device for use with a cartridge holder is provided. The cartridge holder accommodates a cartridge and is configured to attach to the drug delivery device. The drug delivery device comprises an inner bore being configured to receive the cartridge holder. The cartridge holder includes a first blocking feature. Furthermore, the drug delivery device includes a cartridge detector located within the inner bore including a second blocking feature for engagement with the first blocking feature when a portion of the cartridge acts on the cartridge detector. 
     According to a further aspect, a method for securing a cartridge holder into a drug delivery device is disclosed. The method comprises the steps of providing a cartridge holder including a cartridge, wherein the cartridge holder has a first blocking feature. The method further comprises providing a drug delivery device having a second blocking feature and coupling the cartridge holder to the drug delivery device so that a portion of the cartridge acts upon a cartridge detector located within the drug delivery device to align a first blocking feature with a second blocking feature. The first blocking feature may be a part of the cartridge holder and the second blocking feature may be a part of the drug delivery device. In particular, the second blocking feature may be a part of a cartridge detector as described above. The method may further comprise the step of rotating the cartridge holder so that the second blocking feature engages the first blocking feature. Here, a rotation may be only enabled, when the first blocking feature is aligned with the second blocking feature. By the rotation of the cartridge holder and the engagement of the first and second blocking feature, a fastening of the cartridge holder to the device may be enabled. The method may further comprise fastening the cartridge holder to the drug delivery device by a fastening mechanism. 
     These as well as other advantages of various aspects of the present invention will become apparent to those of ordinary skill in the art by reading the following detailed description, with appropriate reference to the accompanying drawings. 
     The scope of the invention is defined by the content of the claims. The invention is not limited to specific embodiments but comprises any combination of elements of different embodiments. Moreover, the invention comprises any combination of claims and any combination of features disclosed by the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are described herein with reference to the drawings, in which: 
         FIG. 1A  illustrates an exemplary pen type drug delivery device; 
         FIG. 1B  illustrates an exemplary drug cartridge; 
         FIG. 2  illustrates a coded cartridge holder including a fastening mechanism enabled by cartridge size; 
         FIG. 3  illustrates a close-up view of the cartridge holder of  FIG. 2  being inserted into the drug delivery device; 
         FIG. 4  illustrates a close-up view of a correct cartridge fastened within the drug delivery device of  FIG. 2 ; 
         FIG. 5  illustrates a close-up view of an incorrect cartridge placed in the drug delivery device of  FIG. 2 ; 
         FIG. 6  illustrates another embodiment of a coded cartridge holder including a fastening mechanism enabled by cartridge size; 
         FIG. 7  illustrates a close-up view of an incorrect cartridge placed in the drug delivery device of  FIG. 6 ; 
         FIG. 8  illustrates yet another embodiment of a coded cartridge holder including a fastening mechanism enabled by cartridge size; and 
         FIG. 9  illustrates a close-up view of an incorrect cartridge placed in the drug delivery device of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1A , there is shown a drug delivery device  100  in the form of a pen type syringe. The drug delivery device  100  comprises a dose setting mechanism  102 , a cartridge holder  104 , and a removable cap  106 . A proximal end  105  of the cartridge holder  104  and a distal end  103  of the dose setting mechanism  102  are removably secured together. The pen type syringe may comprise a re-usable or a disposable pen type syringe. Where the syringe comprises a re-usable device, the cartridge holder  104  and the dose setting mechanism are removably coupled together. In a disposable device, they are permanently coupled together. In  FIG. 1A , the dose setting mechanism  102  comprises a piston rod  109 , such as a threaded piston rod that rotates when a dose is injected. 
     To inject a previously set dose, a double ended needle assembly (not shown) is attached to a distal end  108  of the cartridge holder  104 . Preferably, the distal end  108  of the holder  104  comprises a thread  121  (or other suitable connecting mechanism such as a snap lock, snap fit, form fit, or bayonet lock mechanism) so that the needle assembly may be removably attached to the distal end  108  of the holder. When the drug delivery device  100  is not in use, the removable cap  106  can be releasably retained over the cartridge holder  104 . 
     An inner cartridge cavity  111  defined by the cartridge holder  104  is dimensioned and configured to securely receive and retain a cartridge, such as glass cartridge  120 .  FIG. 1B  illustrates a perspective view of the cartridge  120  that may be used with the drug delivery device  100  illustrated in  FIG. 1A . Typically, the cartridge  120  is manufactured of glass and includes a generally tubular barrel  122  extending from a distal end  130  to a proximal end  132 . The cartridge  120  may be inserted into an inner bore  101  of the drug delivery device  100 . 
     At the distal end  130 , the cartridge  120  includes a smaller diameter neck  126 , wherein this neck  126  projects distally from the shoulder  131  of the barrel  122 . Preferably, the smaller diameter neck  126  is provided with a large diameter annular bead  124  which extends circumferentially thereabout at the extreme distal end of the neck  126  and defines an opening  127 . A pierceable seal or septum  133  is securely held across the opening  127  by a metallic sleeve or a ferrule. 
     Medicament  125  is pre-filled into the cartridge  120  and is retained within this cartridge  120 , in part, by the pierceable seal  133 , a ferrule, and a stopper  128 . The stopper  128  is in sliding fluid-tight engagement with the inner tubular wall of the barrel  122 . Axially directed forces acting upon the stopper  128  during dose injection or dose administration urge the medication  125  from the cartridge  120  though a double ended needle mounted onto the distal end  130  of the cartridge holder  104  and into the injection site. Such axially forces may be provided by the piston rod  109  working in unison with the dose setting member  102 . 
     A portion of the cartridge holder  104  defining the cartridge holder cavity  111  is of substantially uniform diameter represented in  FIG. 1A  by D 1    134 . This diameter D 1    134  is preferably slightly greater than the diameter D 2    136  of the cartridge  120 . The interior of the cartridge holder  104  includes an inwardly-extending annular portion or stop that is dimensioned to prevent the cartridge  120  from moving within the cartridge holder  104 . In this manner, when the cartridge  120  is loaded into the cavity  111  of the cartridge holder  104  and the cartridge holder  104  is then connected to the dose setting member  102 , the cartridge  120  will be securely held within the cartridge holder cavity  111 . The cartridge holder  104  may also include a fastening mechanism for securing the cartridge holder  104  within the drug delivery device  100 , which is described in more detail below. 
     A number of doses of a medicament  125  may be dispensed from the cartridge  120 . Preferably, the cartridge  120  contains a type of medicament that must be administered often, such as one or more times a day. One such medicament is insulin. 
     The dose setting mechanism  102  comprises a dose setter  117  at the proximal end of the dose setting mechanism  102 . In one preferred arrangement, the dose setter  117  is rotated to set a dose. To administer this set dose, the user attaches the needle assembly comprising a double ended needle on the distal end of the cartridge holder  104 . In this manner, the needle assembly pierces the seal  133  of the cartridge  120  and is therefore in liquid communication with the medicament  125 . The user pushes on the dose setter  117  to inject the set dose. The same dose setting and dose administration procedure is followed until the medicament  125  in the cartridge  120  is expended and then a new cartridge must be loaded in the drug delivery device  100 . To exchange an empty cartridge  120 , the user is called upon to remove the cartridge holder  104  from the dose setting mechanism  102 . 
     In accordance with exemplary embodiments, a cartridge holder such as cartridge holder  104  may be coded to a delivery device, so that given cartridge holders may only be connected with intended drug delivery devices and vice versa.  FIG. 2  illustrates a first arrangement of a coded cartridge holder  200 . This coded cartridge holder  200  may be connected to a drug delivery device, such as drug delivery device  100 . For instance, the cartridge holder  200  may be attached to a drug delivery device that has a similarly coded portion. This similarly coded portion may be, for example, a locking mechanism and/or fastening mechanism that is enabled only by the correct length and/or diameter of the cartridge  200 . The coded cartridge holder  200  is intended for use with a drug delivery device similar to the drug delivery device of  FIG. 1A , but a preferred drug delivery device for use with the coded cartridge holder  200  would have a slightly modified inner cavity. 
       FIG. 2  illustrates a first arrangement of a coded cartridge holder  200  of the drug delivery device  100 . In this arrangement, cartridge length indicates a particular drug or medicament. A cartridge, such as cartridge  120 , of a particular length is inserted into the coded cartridge holder  200 , which is then inserted into the drug delivery device  100 . If the cartridge  120  or drug is correct for the device  100 , the cartridge holder  200  may be properly secured to the drug delivery device  100  by a fastening mechanism, such as fasteners  212 ,  216 . However, if the cartridge  120  or drug is not correct for the device  100 , (e.g., the cartridge  120  is too short or too long or too wide), the fastening mechanism will not be enabled to function properly, and the cartridge holder  200  cannot be properly secured to the drug delivery device  100 . Thus, this system ensures that the appropriate cartridge  120  or drug (i.e., the appropriately sized cartridge) can only be fastened to the correct delivery device  100 . 
     The coded cartridge holder  200  may include a first blocking feature  202 ,  204 . The first blocking feature  202 ,  204  may engage with a second blocking feature  210  to ensure that the correct length cartridge  120  and thus the correct drug or medicament is being used with the drug delivery device  100 . The first blocking feature  202 ,  204  may include a slot  202  located on a proximal end  205  of the cartridge holder  200 . The slot  202  may further include a notch  204  arranged perpendicular to the slot  202 , as shown in  FIG. 2 . The notch  204  may retain the second blocking feature  210 , located within an inner bore  101  of the drug delivery device  100 , when the correct length cartridge  120  is inserted into the drug delivery device  100 . The second blocking feature  210  may include a pin  210 . The notch  204  allows the cartridge holder  200  to be rotated and positioned into place within the drug delivery device  100  when the pin  210  travels up through the slot  202 . 
     It should be understood that although the slot  202  and notch  204  are shown on the cartridge holder  200 , they could be located on the drug delivery device  100 . Similarly, the pin  210  may be located on the cartridge holder  200 . Alternatively, one or more slots  202  could be on the cartridge holder  200  and one ore more notches  204  on the drug delivery device  100 . 
     Referring again to  FIG. 2 , the distal end  103  of the drug delivery device  100  may include a cartridge detector  206  located within its inner bore  101 . The second blocking feature  210  may be located on the cartridge detector  206 . The detector  206  may be a sprung plate  206 . The sprung plate  206  may include a spring  208  or any other suitable biasing device. The sprung plate  206  is moveable along a longitudinal axis of the inner bore  101  of the drug delivery device  100 . The sprung plate  206  may be actuated by a cartridge  120  when the correct length cartridge  120  is inserted into the cartridge holder  200 . The sprung plate  206  may also bias the cartridge  120  against the cartridge holder  200  so as to improve dose accuracy. 
     The coded cartridge holder  200  may further include at least one fastening mechanism  212 ,  214 . The fastening mechanism  212 ,  214  is enabled when the second blocking feature  210  engages the first blocking feature  202 ,  204 , which indicates that the correct length cartridge  120  has been inserted into the drug delivery device  100 . The fastening mechanism  212 ,  214  may be a bayonet fastening mechanism, for example. Alternatively, the fastening mechanism may be any suitable fastening mechanism, such as a snap lock, snap fit, form fit, etc. The fastening mechanism  212 ,  214  may include a first fastener  212 , such as a pin  212 , located near the proximal end  205  of the cartridge holder  200 , and a second fastener  214 , which may be a corresponding groove  214  located near the distal end  103  of the drug delivery device  100 . In a preferred embodiment, a second fastening mechanism  216 ,  218  may be included on the cartridge holder  200  to more securely fasten the cartridge holder  104  to the drug delivery device  100 . The second fastening mechanism  216 ,  218  may include a second pin  216  and a second corresponding groove  218 . 
     In operation, as shown in  FIGS. 3 and 4 , when the cartridge holder  200  is first inserted into the drug delivery device  100 , the proximal end of the cartridge  120  contacts the sprung plate  206  in the inner bore of the drug delivery device  100 . This proximal end of the cartridge  120  pushes against the sprung plate  206  to move this plate  206  along the longitudinal axis of the drug delivery device  100 . If the drug cartridge  120  has the correct length for this particular drug delivery device  100 , the pin  210  on the sprung plate  206  will align with the slot  202  in the cartridge holder  104 , and is moved until it is in line with the notch  204 . The cartridge holder  200  may then be rotated so that the pin  210  slides along the notch  204 . As the pin  210  slides along the notch  204 , the pins  212 ,  216  of the fastening mechanisms  212 ,  214 ,  216 ,  218  also engage with the corresponding grooves  214 ,  218 . The cartridge holder  200  is thus properly fastened to the drug delivery device  100 . If the drug cartridge  120  is too short or too long and is therefore not the correct cartridge  120  for that particular drug delivery device  100 , the pin  210  will not properly align with the notch  204 . As such, the pins  212 ,  216  will not engage with the grooves  214 ,  218  on the drug delivery device  100 . Thus, the cartridge holder  200  cannot be rotated or fastened to the drug delivery device  100 , as shown in  FIG. 5 . 
     One advantage of the disclosed coded cartridge holder system is that it prevents assembly of cartridges that are either too short or too long for a given drug delivery device, thereby preventing the accidental intake of the wrong type of drug by a patient. 
       FIGS. 6 and 7  illustrate a second arrangement of a coded cartridge holder  300  for use with a cartridge, such as the cartridge  120  illustrated in  FIG. 1B , that may be used with a pen type drug delivery device, such as the drug delivery device  100  illustrated in  FIG. 1A . Similar to the coded cartridge holder  200  illustrated in  FIGS. 2-5 , this cartridge configuration comprises a cartridge  120  inserted into a cartridge holder  300 , similar to cartridge holder  104  illustrated in  FIG. 1A , the size of the cartridge  120  indicating a particular drug. 
     The coded cartridge holder  300  includes an inner bore  302  being configured to receive a cartridge  120 . The cartridge holder  300  may further include a fastening mechanism  304 ,  306  which interacts with a proximal end  132  of the cartridge  120 . In this way, when a correctly dimensioned cartridge  120  is placed in the cartridge holder  300 , it may be fastened by the fastening mechanism  304 . Therefore, if an incorrectly dimensioned cartridge  120  is inserted into the cartridge holder  300 , the holder  300  can not be connected to the drug delivery device  100 . 
     The fastening mechanism  304 ,  306  may include at least one inwardly sprung arm  304 . In a preferred embodiment, which is shown in  FIG. 6 , the fastening mechanism  304 ,  306  includes two inwardly sprung arms  304 ,  306 . Although the embodiment shows two arms  304 ,  306 , any number of arms may be used. The inwardly sprung arms  304 ,  306  may be molded as part of the cartridge holder  300 , or they may be a separate component. The inwardly sprung arms  304 ,  306  may each include an outwardly projecting pin  308 ,  310 . 
     As well as coding the drug by cartridge length, this embodiment also allows coding by cartridge diameter. For example, if the diameter of the cartridge  120  is too large, the cartridge will not fit in the holder  300 . Further, if the diameter of the cartridge  120  is too small, the fastening mechanism  304 ,  306  would not be enabled and thus could not secure the cartridge holder to the drug delivery device  100 . 
     In operation, when the cartridge  120  is inserted into the cartridge holder  300 , the inwardly sprung arms  304 ,  306  are pushed outwards by the proximal end  132  of the cartridge  120  so that they may act as fastening features. The outwardly projecting pins  308 ,  310  may then mate with corresponding grooves on the drug delivery device  100 , such as grooves  214 ,  218  shown in  FIG. 2 , to securely fasten the cartridge holder  300  to the drug delivery device  100 . 
     If the cartridge  120  is too long, it may interfere with the drug delivery device  100  during fastening. If the cartridge  120  is too short, as shown in  FIG. 7 , the outwardly projecting pins  308 ,  310  of the inwardly sprung arms  304 ,  306  will not be exposed and therefore will not be able to mate with the corresponding grooves, such as grooves  214 ,  218  on the drug delivery device  100 . 
     To ensure adequate strength, the inwardly sprung arms  304 ,  306  may be flexible in the radial direction, but relatively stiff in an axial direction. Alternatively, the inwardly sprung arms may be supported in an axial direction. 
     It should be understood that any suitable fastening mechanism can be used to secure the cartridge holder  300  to the drug delivery device  100 , for example a thread, a pin following a groove or other bayonet, or snap fit. 
     In one embodiment, slots (not shown) may be formed in the cartridge holder  300  to allow access for removing a cartridge  120  (e.g., an incorrect short cartridge  120 ). Alternatively, a separate removal tool could be supplied with the drug delivery device  100 . 
     One advantage of such a coded cartridge arrangement is that it prevents use of cartridges  120  that are either too short or too long for a particular drug delivery device, or where the cartridge diameter is too large or too small, thereby preventing the accidental intake of the wrong type of drug by a patient. 
       FIGS. 8 and 9  illustrate a yet another arrangement of a coded cartridge holder, similar to cartridge holder  104 , for use with a cartridge  120  that may be used with a drug delivery device, such as the pen type drug delivery device  100  illustrated in  FIG. 1A . In this embodiment, an elliptical ring  400  may be attached into the cartridge holder (not shown) to act as the fastening mechanism for fastening the cartridge holder to the drug delivery device  100 . The elliptical ring  400  may include one or more outwardly protruding tabs  402 ,  404 . These tabs  402 ,  404  may engage with corresponding grooves, such as grooves  214 ,  218  as shown in  FIG. 2 , on the drug delivery device  100 . It should be understood that any suitable fastening mechanism can be used to secure the cartridge holder to the drug delivery device  100  instead of the protruding tabs, for example a thread, a pin following a groove or other bayonet, or snap fit. 
     In operation, during the insertion of a correct cartridge into a cartridge holder, such as cartridge  120  into cartridge holder  104  illustrated in  FIGS. 1A and 1B , the cartridge forces the elliptical ring  400  into a circular shape, thereby allowing the fastening mechanism, protruding tabs  402 ,  404 , to protrude outwardly as shown in  FIG. 8 . The protruding tabs  402 ,  404  may then engage with corresponding grooves, such as grooves  214 ,  218  as shown in  FIG. 2 , on the drug delivery device  100  to securely fasten the cartridge  120  and cartridge holder  104  to the drug delivery device  100 . 
     As shown in  FIG. 9 , if the cartridge  120  is incorrect for the drug delivery device  100 , (e.g., the cartridge  120  is too short), the elliptical ring  400  will not be forced into a circular shape, and the protruding tabs  402 ,  404  will not engage with the corresponding grooves. To remove an incorrect cartridge  120 , such as a cartridge  120  that is too short, the user may compress the ellipse on its major axis. 
     The disclosed coding system results in a number of advantages. For example, the disclosed coded cartridge holder arrangements assist a user to distinguish between medicaments, thereby helping to ensure that a delivery device can only be used with a medicament for which the device is intended. 
     The disclosed coded cartridge holder also prevents a user from completing one or more of the following actions: fully inserting the cartridge into an incorrect cartridge holder or attaching the cartridge and/or cartridge holder onto an incorrect dose setting mechanism. 
     The disclosed coded cartridge holder also results in a low cost coding mechanism since the disclosed cartridge holders do not require a large number of parts and can be manufactured in a cost effective manner. Moreover, there are quite a large number of different cartridge holder coding configurations between the cartridge holder and the drug delivery device that may be used. Consequently, with the disclosed coding schemes, a large number of medicaments can be distinguished from one another. In addition, with the disclosed coding schemes, if a user attempts to load an incorrect cartridge into a cartridge holder designed for a different cartridge, the user will be alerted at an early stage of the drug delivery device assembly process. 
     In addition, the disclosed system can be used to prevent errors during manufacturing, when inserting cartridges into disposable cartridge holders or disposable devices. With an incorrect drug (and hence incorrectly coded cartridge holder), the user is alerted at an early stage of the assembly process. 
     Exemplary embodiments of the present invention have been described. Those skilled in the art will understand, however, that changes and modifications may be made to these arrangements without departing from the true scope and spirit of the present invention, which is defined by the claims.