Abstract:
The technical problem of providing a channel, which is more reliable, prevents contamination of guided liquids and which can be produced in an easy and cost saving way, is solved by an apparatus, comprising a plastic part, a channel within said plastic part configured to guide at least one fluid, wherein said channel is configured to be used in a medical device, wherein said channel is a y-channel having three ends and wherein said channel is produced with gas injection technique and/or water injection technique. The technical problem is further solved by a method to produce at least a part of a medical device, comprising the steps of producing a y-channel within a plastic part with gas injection technique and/or water injection technique and opening said y-channel to produce at least one opening.

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/EP2012/058262 filed May 4, 2012, which claims priority to European Patent Application No. 11165123.8 filed May 6, 2011. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
     
    
     FIELD OF INVENTION 
       [0002]    The present patent application relates to medical devices of delivering at least two drug agents from separate reservoirs. Such drug agents may comprise a first and a second medicament. The medical device includes a dose setting mechanism for delivering the drug automatically or manually by the user. 
       BACKGROUND 
       [0003]    The drug agents may be contained in two or more multiple dose reservoirs, containers or packages, each containing independent (single drug compound) or pre-mixed (co-formulated multiple drug compounds) drug agents. 
         [0004]    Certain disease states require treatment using one or more different medicaments. Some drug compounds need to be delivered in a specific relationship with each other in order to deliver the optimum therapeutic dose. The present patent application is of particular benefit where combination therapy is desirable, but not possible in a single formulation for reasons such as, but not limited to, stability, compromised therapeutic performance and toxicology. 
         [0005]    For example, in some cases it might be beneficial to treat a diabetic with a long acting insulin (also may be referred to as the first or primary medicament) along with a glucagon-like peptide-1 such as GLP-1 or GLP-1 analog (also may be referred to as the second drug or secondary medicament). 
       SUMMARY 
       [0006]    Accordingly, there exists a need to provide devices for the delivery of two or more medicaments in a single injection or delivery step that is simple for the user to perform without complicated physical manipulations of the drug delivery device. The proposed drug delivery device provides separate storage containers or cartridge retainers for two or more active drug agents. These active drug agents are then only combined and/or delivered to the patient during a single delivery procedure. These active agents may be administered together in a combined dose or alternatively, these active agents may be combined in a sequential manner, one after the other. 
         [0007]    The drug delivery device also allows for the opportunity of varying the quantity of the medicaments. For example, one fluid quantity can be varied by changing the properties of the injection device (e.g., setting a user variable dose or changing the device&#39;s “fixed” dose). The second medicament quantity can be changed by manufacturing a variety of secondary drug containing packages with each variant containing a different volume and/or concentration of the second active agent. 
         [0008]    The drug delivery device may have a single dispense interface. This interface may be configured for fluid communication with the primary reservoir and with a secondary reservoir of medicament containing at least one drug agent. The drug dispense interface can be a type of outlet that allows the two or more medicaments to exit the system and be delivered to the patient. 
         [0009]    The combination of compounds as discrete units or as a mixed unit can be delivered to the body via a double-ended needle assembly. This would provide a combination drug injection system that, from a user&#39;s perspective, would be achieved in a manner that closely matches the currently available injection devices that use standard needle assemblies. One possible delivery procedure may involve the following steps: 
         [0010]    1. Attach a dispense interface to a distal end of the electro-mechanical injection device. The dispense interface comprises a first and a second proximal needle. The first and second needles pierce a first reservoir containing a primary compound and a second reservoir containing a secondary compound, respectively. 
         [0011]    2. Attach a dose dispenser, such as a double-ended needle assembly, to a distal end of the dispense interface. In this manner, a proximal end of the needle assembly is in fluidic communication with both the primary compound and secondary compound. 
         [0012]    3. Dial up/set a desired dose of the primary compound from the injection device, for example, via a graphical user interface (GUI). 
         [0013]    4. After the user sets the dose of the primary compound, the micro-processor controlled control unit may determine or compute a dose of the secondary compound and preferably may determine or compute this second dose based on a previously stored therapeutic dose profile. It is this computed combination of medicaments that will then be injected by the user. The therapeutic dose profile may be user selectable. 
         [0014]    5. Optionally, after the second dose has been computed, the device may be placed in an armed condition. In such an optional armed condition, this may be achieved by pressing and/or holding an “OK” button on a control panel. This condition may provide for greater than a predefined period of time before the device can be used to dispense the combined dose. 
         [0015]    6. Then, the user will insert or apply the distal end of the dose dispenser (e.g., a double ended needle assembly) into the desired injection site. The dose of the combination of the primary compound and the secondary compound (and potentially a third medicament) is administered by activating an injection user interface (e.g., an injection button). 
         [0016]    Both medicaments may be delivered via one injection needle or dose dispenser and in one injection step. This offers a convenient benefit to the user in terms of reduced user steps compared to administering two separate injections. 
         [0017]    In any case, it is very advantageous, if there is a channel, which guides and combines the liquids of the at least two medicaments, so that the medicaments only need to be ejected via a single injection needle. 
         [0018]    In the state of the art, this guide is produced for example from at least two, often more, single parts which need to be fixed together. The problem of such techniques is that it can result in issues like bad connections due to improperly fixed parts. This can then result in leakages of the guided liquids and/or even a blockage of the channel due to small parts being caught in the channel. Those small parts might, for example, result from microwave welding in order to fix the parts together. 
         [0019]    Moreover, in order to tightly fix the parts together, which are building the channel, adhesives in form of glue might be used. This results in the constant risk of such chemicals finding their way into the guided liquid medicaments with possibly causing side effects for the user. 
         [0020]    Since the channels are small, it is not possible to produce such channels with standard injection molding techniques. 
         [0021]    The invention faces the technical problem of providing a channel, which is more reliable, prevents contamination of guided liquids and which can be produced in an easy and cost saving way. 
         [0022]    The technical problem is solved by an apparatus, comprising a plastic part, a channel within said plastic part configured to guide at least one fluid, wherein said channel is configured to be used in a medical device, wherein said channel is a y-channel having three ends and wherein said channel is produced with gas injection technique and/or water injection technique. 
         [0023]    By using the gas injection technique (GIT) or water injection technique (WIT), the y-channel can be produced in a substantially one part design. The y-channel is provided in a single plastic part, without having to produce the plastic part from further single parts. Thus the aforementioned disadvantages are avoided, since no parts need to be fixed together to build the inner surface of the y-channel being able to guide a liquid. Moreover by using the GIT/WIT saves assembly steps and the y-channel is thus easier and more efficient to produce. 
         [0024]    It is especially advantageous that by using GIT/WIT no chemical changes of the plastic takes place. Hence no chemical reactions between the plastic and the liquids like medicaments can occur. 
         [0025]    A y-channel is understood to be any channel having three ends. Thus a T-piece, for example, would also be a y-channel in this sense. Preferably, a y-channel has two substantially identical channel arms, having an angle of less then 180° between them, and a third arm at the intersection of the two first arms, while the third arm extends away from the angle being less than 180°. It is preferred if the axis of the third arm substantially cuts the angle between the first arms in half. This way the guide of the liquid from the first and second arm into the third arm is supported with the y-channel in an upright (third arm facing down) position. Though an asymmetrical shape with the third arm not cutting the angle between the first arms in half is also possible. 
         [0026]    GIT is a technique, where a molten material, for example molten plastic, is injected into a substantially closed mold, which is then partially filled with the molten material. Right before or after the end of this partial filling process a gas injection into the molten material is started. While the outer parts of the molten material already start to cool down and solidify, the gas is pushing aside the molten core of the material and pushing the material against the inner walls of the mold thus creating a piece having an outer shape substantially determined by the inner shape of the mold and at the same time an inner cavity produced by the gas injection. The pressure of the gas may also be maintained for a certain time even after the molten material with its inner gas core already fills out the whole mold, in order to allow the material to cool down without deforming again. Hence, this technique is also referred to as internal gas pressure injection moulding. 
         [0027]    The same technique may also be performed with water instead of gas, leading to the technique called WIT or internal water pressure injection moulding. 
         [0028]    By utilizing GIT/WIT for the production of a y-channel, which can be implemented in a medical device, the y-channel can be implemented in the one piece plastic part without any needs for assembling. 
         [0029]    The plastic part has preferably substantially the form of the y-channel. Since the form of the inner cavity produced by GIT/WIT strongly depends on the form of the mold, the mold and thus the outer form of the plastic part preferably also have the form of the y-channel. By providing a plastic part substantially in the form the y-channel, the production of the y-channel inside the plastic part is facilitated. 
         [0030]    Preferably said y-channel has an opening at all three ends. This is in particular advantageous if two liquids shall be guided through the y-channel and the two liquids shall be ejected from the y-channel via a common opening. The first and second arm of the y-channel can be used for one liquid each and the third arm can be used as the common opening. 
         [0031]    The opening can be achieved by opening the ends by mechanical means, such as mechanical cutting or drilling, or by laser cutting, for example. Preferably at least one of said openings is produced by cutting said y-channel, because this results in a clean opening, and the cutting can be easily implemented in the production process. 
         [0032]    According to another embodiment said y-channel has a substantially constant diameter. A constant diameter means that every arm of the y-channel has substantially the same diameter. This way the production is further facilitated and the y-channel can easily be produced by GIT/WIT. 
         [0033]    It is further advantageous, if only the first and the second arm of the y-channel have substantially the same diameter and the third arm has a larger diameter. This optimises the fluidic flow of the liquids inside the y-channel, since the two liquids guided by the first and second arm of the y-channel combine in the third arm. 
         [0034]    Preferably said y-channel has a diameter between 0.08 and 3 mm, in particular preferably smaller than 2 mm, especially preferably smaller than 1 mm. This does not necessarily mean that the whole y-channel has a single diameter, but that the diameter may also vary in the given range. Those diameters match those of standard needles used for medical purposes. This further optimises the fluidic flow of the liquids and reduces the dead volume inside the y-channel. By utilizing GIT/WIT y-channels with such diameters are producible more easily and economically in a one part design. 
         [0035]    According to a further embodiment said y-channel is substantially axially symmetrical. The symmetry axis is preferably the axis of the third arm of the y-channel. On the one hand this further facilitates the production process, since too complex or asymmetric geometries might render the GIT/WIT production more unreliable. On the other hand the symmetry supports an equal mixing of two liquids being guided by the first and second arm of the y-channel and combining in the third arm. 
         [0036]    According to another embodiment the apparatus further comprises an inner body and/or a main outer body. The plastic part with the y-channel by this means can be easily implemented into or connected to further devices. In particular the plastic part may be implemented in the inner body. The inner body may comprise a two part design in between those two parts the plastic part can be implemented and the two parts of the inner body can be fixed by common means such as form fit, force fit or material bonding. This inner body then can be implemented in the same manner into a main outer body, for example of a medical device. Though, the plastic part can also be directly implemented into a main outer body. The inner body or the main outer body may comprise further elements, such as piercing needles, valve seals and/or a septum. In particular one piercing needle for the first and second arm of the y-channel is provided and a septum to seal the opening of the third arm of the y-channel. 
         [0037]    Preferably said apparatus is a dispense interface. The dispense interface is in particular attachable to a cartridge holder on the one side and a dose dispenser on the other side. The main outer body can provide means for attaching the dispense interface to a cartridge holder as well as means for attaching the dispense interface to a dose dispenser. 
         [0038]    The technical problem is further solved by a method to produce at least a part of a medical device, comprising the steps of producing a y-channel within a plastic part with gas injection technique and/or water injection technique and opening said y-channel to produce at least one opening. 
         [0039]    By using the gas injection technique (GIT) or water injection technique (WIT), the y-channel can be produced in a substantially one part design. The y-channel is provided in a single plastic part, without having to produce the plastic part from further single parts. Thus the disadvantages known from the state of the art are avoided, since no parts need to be fixed together to build the inner surface of the y-channel being able to guide a liquid. Moreover by using the GIT/WIT saves assembly steps and the y-channel is thus easier and more efficient to produce. 
         [0040]    As described above, a molten material and a gas or water injection is used to create the y-channel within the plastic part. Generally the injection sites of the molten plastic and the gas can be independently positioned from each other. The gas injection can take place over the same injection site as the molten plastic for example. It is preferred though, that the gas injection site is different from the molten plastic injection site. This reduces the complexity of the tools needed. There might as well be multiple injection sites for gas. 
         [0041]    The same applies to WIT. The use of gas is preferred though, because he implementation of water into the production process is more complex than that of gas and with GIT the parts simply do not become wet. 
         [0042]    In a preferred embodiment all three ends of said y-channel are opened. As described above, the opening can be achieved by opening the ends by mechanical means, such as mechanical cutting or drilling, or by laser cutting, for example. Preferably at least one of said openings is produced by cutting said y-channel, because this results in a clean opening, and the cutting can be easily implemented in the production process. 
         [0043]    Preferably said plastic part is further implemented into an inner body. The inner body may comprise a two part design in between those two parts the plastic part can be implemented and the two parts of the inner body can be fixed by common means such as form fit, force fit or material bonding. The plastic part with the y-channel by this means can be easily implemented into or connected to further devices. This inner body then can be implemented in the same manner into a main outer body, for example of a medical device. 
         [0044]    It is preferred when said plastic part is further implemented into a main outer body of a dispense interface. The main outer body may comprise further elements, such as piercing needles, valve seals and/or a septum. In particular one piercing needle for the first and second arm of the y-channel is provided and a septum to seal the opening of the third arm of the y-channel. The dispense interface is in particular attachable to a cartridge holder on the one side and a dose dispenser on the other side. The main outer body can provide means for attaching the dispense interface to a cartridge holder as well as means for attaching the dispense interface to a dose dispenser. 
         [0045]    According to a further embodiment said y-channel has a diameter between 0.08 and 3 mm, in particular preferably smaller than 2 mm, especially preferably smaller than 1 mm. This does not necessarily mean that the whole y-channel has a single diameter, but that the diameter may also vary in the given range. Those diameters match those of standard needles used for medical purposes. This further optimises the fluidic flow of the liquids inside the y-channel. By utilizing GIT/WIT y-channels with such diameters are producible more easily and economically in a one part design. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0046]    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, in which: 
           [0047]      FIG. 1  illustrates a perspective view of the delivery device illustrated in  FIGS. 1   a  and  1   b  with an end cap of the device removed; 
           [0048]      FIG. 2  illustrates a perspective view of the delivery device distal end showing the cartridge; 
           [0049]      FIG. 3  illustrates a perspective view of the cartridge holder illustrated in  FIG. 1  with one cartridge retainer in an open position; 
           [0050]      FIG. 4  illustrates a dispense interface and a dose dispenser that may be removably mounted on a distal end of the delivery device illustrated in  FIG. 1 ; 
           [0051]      FIG. 5  illustrates the dispense interface and the dose dispenser illustrated in  FIG. 4  mounted on a distal end of the delivery device illustrated in  FIG. 1 ; 
           [0052]      FIG. 6  illustrates one arrangement of the dose dispenser that may be mounted on a distal end of the delivery device; 
           [0053]      FIG. 7  illustrates a perspective view of the dispense interface illustrated in  FIG. 4 ; 
           [0054]      FIG. 8  illustrates another perspective view of the dispense interface illustrated in  FIG. 4 ; 
           [0055]      FIG. 9  illustrates a cross-sectional view of the dispense interface illustrated in  FIG. 4 ; 
           [0056]      FIG. 10  illustrates an exploded view of the dispense interface illustrated in  FIG. 4 ; 
           [0057]      FIG. 11  illustrates a cross-sectional view of the dispense interface and dose dispenser mounted onto a drug delivery device, such as the device illustrated in  FIG. 1 ; 
           [0058]      FIG. 12   a - d  illustrate the production of a y-channel with GIT/WIT; 
           [0059]      FIG. 13  illustrates a cross-sectional view of a dispense interface with a y-channel. 
       
    
    
     DETAILED DESCRIPTION 
       [0060]    The drug delivery device illustrated in  FIG. 1  comprises a main body  14  that extends from a proximal end  16  to a distal end  15 . At the distal end  15 , a removable end cap or cover  18  is provided. This end cap  18  and the distal end  15  of the main body  14  work together to provide a snap fit or form fit connection so that once the cover  18  is slid onto the distal end  15  of the main body  14 , this frictional fit between the cap and the main body outer surface  20  prevents the cover from inadvertently falling off the main body. 
         [0061]    The main body  14  contains a micro-processor control unit, an electro-mechanical drive train, and at least two medicament reservoirs. When the end cap or cover  18  is removed from the device  10  (as illustrated in  FIG. 1 ), a dispense interface  200  is mounted to the distal end  15  of the main body  14 , and a dose dispenser (e.g., a needle assembly) is attached to the interface. The drug delivery device  10  can be used to administer a computed dose of a second medicament (secondary drug compound) and a variable dose of a first medicament (primary drug compound) through a single needle assembly, such as a double ended needle assembly. 
         [0062]    A control panel region  60  is provided near the proximal end of the main body  14 . Preferably, this control panel region  60  comprises a digital display  80  along with a plurality of human interface elements that can be manipulated by a user to set and inject a combined dose. In this arrangement, the control panel region comprises a first dose setting button  62 , a second dose setting button  64  and a third button  66  designated with the symbol “OK.” In addition, along the most proximal end of the main body, an injection button  74  is also provided (not visible in the perspective view of  FIG. 1 ). 
         [0063]    The cartridge holder  40  can be removably attached to the main body  14  and may contain at least two cartridge retainers  50  and  52 . Each retainer is configured so as to contain one medicament reservoir, such as a glass cartridge. Preferably, each cartridge contains a different medicament. 
         [0064]    In addition, at the distal end of the cartridge holder  40 , the drug delivery device illustrated in  FIG. 1  includes a dispense interface  200 . As will be described in relation to  FIG. 4 , in one arrangement, this dispense interface  200  includes a main outer body  212  that is removably attached to a distal end  42  of the cartridge housing  40 . As can be seen in  FIG. 1 , a distal end  214  of the dispense interface  200  preferably comprises a needle hub  216 . This needle hub  216  may be configured so as to allow a dose dispenser, such as a conventional pen type injection needle assembly, to be removably mounted to the drug delivery device  10 . 
         [0065]    Once the device is turned on, the digital display  80  shown in  FIG. 1  illuminates and provides the user certain device information, preferably information relating to the medicaments contained within the cartridge holder  40 . For example, the user is provided with certain information relating to both the primary medicament (Drug A) and the secondary medicament (Drug B). 
         [0066]    As shown in  FIG. 3 , the first and a second cartridge retainers  50 ,  52  comprise hinged cartridge retainers. These hinged retainers allow user access to the cartridges.  FIG. 3  illustrates a perspective view of the cartridge holder  40  illustrated in  FIG. 1  with the first hinged cartridge retainer  50  in an open position.  FIG. 3  illustrates how a user might access the first cartridge  90  by opening up the first retainer  50  and thereby having access to the first cartridge  90 . 
         [0067]    As mentioned above when discussing  FIG. 1 , a dispense interface  200  is coupled to the distal end of the cartridge holder  40 .  FIG. 4  illustrates a flat view of the dispense interface  200  unconnected to the distal end of the cartridge holder  40 . A dose dispenser or needle assembly that may be used with the interface  200  is also illustrated and is provided in a protective outer cap  420 . 
         [0068]    In  FIG. 5 , the dispense interface  200  illustrated in  FIG. 4  is shown coupled to the cartridge holder  40 . The axial attachment means between the dispense interface  200  and the cartridge holder  40  can be any known axial attachment means to those skilled in the art, including snap locks, snap fits, snap rings, keyed slots, and combinations of such connections. The connection or attachment between the dispense interface and the cartridge holder may also contain additional features (not shown), such as connectors, stops, splines, ribs, grooves, pips, clips and the like design features, that ensure that specific hubs are attachable only to matching drug delivery devices. Such additional features would prevent the insertion of a non-appropriate secondary cartridge to a non-matching injection device. 
         [0069]      FIG. 5  also illustrates the needle assembly  400  and protective cover  420  coupled to the distal end of the dispense interface  200  that may be screwed onto the needle hub of the interface  200 .  FIG. 6  illustrates a cross sectional view of the double ended needle assembly  402  mounted on the dispense interface  200  in  FIG. 5 . 
         [0070]    The needle assembly  400  illustrated in  FIG. 6  comprises a double ended needle  406  and a hub  401 . The double ended needle or cannula  406  is fixedly mounted in a needle hub  401 . This needle hub  401  comprises a circular disk shaped element which has along its periphery a circumferential depending sleeve  403 . Along an inner wall of this hub member  401 , a thread  404  is provided. This thread  404  allows the needle hub  401  to be screwed onto the dispense interface  200  which, in one preferred arrangement, is provided with a corresponding outer thread along a distal hub. At a center portion of the hub element  401  there is provided a protrusion  402 . This protrusion  402  projects from the hub in an opposite direction of the sleeve member. A double ended needle  406  is mounted centrally through the protrusion  402  and the needle hub  401 . This double ended needle  406  is mounted such that a first or distal piercing end  405  of the double ended needle forms an injecting part for piercing an injection site (e.g., the skin of a user). 
         [0071]    Similarly, a second or proximal piercing end  406  of the needle assembly  400  protrudes from an opposite side of the circular disc so that it is concentrically surrounded by the sleeve  403 . In one needle assembly arrangement, the second or proximal piercing end  406  may be shorter than the sleeve  403  so that this sleeve to some extent protects the pointed end of the back sleeve. The needle cover cap  420  illustrated in  FIGS. 4 and 5  provides a form fit around the outer surface  403  of the hub  401 . 
         [0072]    Referring now to  FIGS. 4 to 11 , one preferred arrangement of this interface  200  will now be discussed. In this one preferred arrangement, this interface  200  comprises: 
         [0073]    a. a main outer body  210 , 
         [0074]    b. an first inner body  220 , 
         [0075]    c. a second inner body  230 , 
         [0076]    d. a first piercing needle  240 , 
         [0077]    e. a second piercing needle  250 , 
         [0078]    f. a valve seal  260 , and 
         [0079]    g. a septum  270 . 
         [0080]    The main outer body  210  comprises a main body proximal end  212  and a main body distal end  214 . At the proximal end  212  of the outer body  210 , a connecting member is configured so as to allow the dispense interface  200  to be attached to the distal end of the cartridge holder  40 . Preferably, the connecting member is configured so as to allow the dispense interface  200  to be removably connected the cartridge holder  40 . In one preferred interface arrangement, the proximal end of the interface  200  is configured with an upwardly extending wall  218  having at least one recess. For example, as may be seen from  FIG. 8 , the upwardly extending wall  218  comprises at least a first recess  217  and a second recess  219 . 
         [0081]    Preferably, the first and the second recesses  217 ,  219  are positioned within this main outer body wall so as to cooperate with an outwardly protruding member located near the distal end of the cartridge housing  40  of the drug delivery device  10 . For example, this outwardly protruding member  48  of the cartridge housing may be seen in  FIGS. 4 and 5 . A second similar protruding member is provided on the opposite side of the cartridge housing. As such, when the interface  200  is axially slid over the distal end of the cartridge housing  40 , the outwardly protruding members will cooperate with the first and second recess  217 ,  219  to form an interference fit, form fit, or snap lock. Alternatively, and as those of skill in the art will recognize, any other similar connection mechanism that allows for the dispense interface and the cartridge housing  40  to be axially coupled could be used as well. 
         [0082]    The main outer body  210  and the distal end of the cartridge holder  40  act to form an axially engaging snap lock or snap fit arrangement that could be axially slid onto the distal end of the cartridge housing. In one alternative arrangement, the dispense interface  200  may be provided with a coding feature so as to prevent inadvertent dispense interface cross use. That is, the inner body of the hub could be geometrically configured so as to prevent an inadvertent cross use of one or more dispense interfaces. 
         [0083]    A mounting hub is provided at a distal end of the main outer body  210  of the dispense interface  200 . Such a mounting hub can be configured to be releasably connected to a needle assembly. As just one example, this connecting means  216  may comprise an outer thread that engages an inner thread provided along an inner wall surface of a needle hub of a needle assembly, such as the needle assembly  400  illustrated in  FIG. 6 . Alternative releasable connectors may also be provided such as a snap lock, a snap lock released through threads, a bayonet lock, a form fit, or other similar connection arrangements. 
         [0084]    The dispense interface  200  further comprises a first inner body  220 . Certain details of this inner body are illustrated in  FIG. 8-11 . Preferably, this first inner body  220  is coupled to an inner surface  215  of the extending wall  218  of the main outer body  210 . More preferably, this first inner body  220  is coupled by way of a rib and groove form fit arrangement to an inner surface of the outer body  210 . For example, as can be seen from  FIG. 9 , the extending wall  218  of the main outer body  210  is provided with a first rib  213   a  and a second rib  213   b . This first rib  213   a  is also illustrated in  FIG. 10 . These ribs  213   a  and  213   b  are positioned along the inner surface  215  of the wall  218  of the outer body  210  and create a form fit or snap lock engagement with cooperating grooves  224   a  and  224   b  of the first inner body  220 . In a preferred arrangement, these cooperating grooves  224   a  and  224   b  are provided along an outer surface  222  of the first inner body  220 . 
         [0085]    In addition, as can be seen in  FIG. 8-10 , a proximal surface  226  near the proximal end of the first inner body  220  may be configured with at least a first proximally positioned piercing needle  240  comprising a proximal piercing end portion  244 . Similarly, the first inner body  220  is configured with a second proximally positioned piercing needle  250  comprising a proximally piercing end portion  254 . Both the first and second needles  240 ,  250  are rigidly mounted on the proximal surface  226  of the first inner body  220 . 
         [0086]    Preferably, this dispense interface  200  further comprises a valve arrangement. Such a valve arrangement could be constructed so as to prevent cross contamination of the first and second medicaments contained in the first and second reservoirs, respectively. A preferred valve arrangement may also be configured so as to prevent back flow and cross contamination of the first and second medicaments. 
         [0087]    In one preferred system, dispense interface  200  includes a valve arrangement in the form of a valve seal  260 . Such a valve seal  260  may be provided within a cavity  231  defined by the second inner body  230 , so as to form a holding chamber  280 . Preferably, cavity  231  resides along an upper surface of the second inner body  230 . This valve seal comprises an upper surface that defines both a first fluid groove  264  and second fluid groove  266 . For example,  FIG. 9  illustrates the position of the valve seal  260 , seated between the first inner body  220  and the second inner body  230 . During an injection step, this seal valve  260  helps to prevent the primary medicament in the first pathway from migrating to the secondary medicament in the second pathway, while also preventing the secondary medicament in the second pathway from migrating to the primary medicament in the first pathway. Preferably, this seal valve  260  comprises a first non-return valve  262  and a second non-return valve  268 . As such, the first non-return valve  262  prevents fluid transferring along the first fluid pathway  264 , for example a groove in the seal valve  260 , from returning back into this pathway  264 . Similarly, the second non-return valve  268  prevents fluid transferring along the second fluid pathway  266  from returning back into this pathway  266 . 
         [0088]    Together, the first and second grooves  264 ,  266  converge towards the non-return valves  262  and  268  respectively, to then provide for an output fluid path or a holding chamber  280 . This holding chamber  280  is defined by an inner chamber defined by a distal end of the second inner body both the first and the second non return valves  262 ,  268  along with a pierceable septum  270 . As illustrated, this pierceable septum  270  is positioned between a distal end portion of the second inner body  230  and an inner surface defined by the needle hub of the main outer body  210 . 
         [0089]    The holding chamber  280  terminates at an outlet port of the interface  200 . This outlet port  290  is preferably centrally located in the needle hub of the interface  200  and assists in maintaining the pierceable seal  270  in a stationary position. As such, when a double ended needle assembly is attached to the needle hub of the interface (such as the double ended needle illustrated in  FIG. 6 ), the output fluid path allows both medicaments to be in fluid communication with the attached needle assembly. 
         [0090]    The hub interface  200  further comprises a second inner body  230 . As can be seen from  FIG. 9 , this second inner body  230  has an upper surface that defines a recess, and the valve seal  260  is positioned within this recess. Therefore, when the interface  200  is assembled as shown in  FIG. 9 , the second inner body  230  will be positioned between a distal end of the outer body  210  and the first inner body  220 . Together, second inner body  230  and the main outer body hold the septum  270  in place. The distal end of the inner body  230  may also form a cavity or holding chamber that can be configured to be fluid communication with both the first groove  264  and the second groove  266  of the valve seal. 
         [0091]    Axially sliding the main outer body  210  over the distal end of the drug delivery device attaches the dispense interface  200  to the multi-use device. In this manner, a fluid communication may be created between the first needle  240  and the second needle  250  with the primary medicament of the first cartridge and the secondary medicament of the second cartridge, respectively. 
         [0092]      FIG. 11  illustrates the dispense interface  200  after it has been mounted onto the distal end  42  of the cartridge holder  40  of the drug delivery device  10  illustrated in  FIG. 1 . A double ended needle  400  is also mounted to the distal end of this interface. The cartridge holder  40  is illustrated as having a first cartridge containing a first medicament and a second cartridge containing a second medicament. 
         [0093]    When the interface  200  is first mounted over the distal end of the cartridge holder  40 , the proximal piercing end  244  of the first piercing needle  240  pierces the septum of the first cartridge  90  and thereby resides in fluid communication with the primary medicament  92  of the first cartridge  90 . A distal end of the first piercing needle  240  will also be in fluid communication with a first fluid path groove  264  defined by the valve seal  260 . 
         [0094]    Similarly, the proximal piercing end  254  of the second piercing needle  250  pierces the septum of the second cartridge  100  and thereby resides in fluid communication with the secondary medicament  102  of the second cartridge  100 . A distal end of this second piercing needle  250  will also be in fluid communication with a second fluid path groove  266  defined by the valve seal  260 . 
         [0095]      FIG. 11  illustrates a preferred arrangement of such a dispense interface  200  that is coupled to a distal end  15  of the main body  14  of drug delivery device  10 . Preferably, such a dispense interface  200  is removably coupled to the cartridge holder  40  of the drug delivery device  10 . 
         [0096]    As illustrated in  FIG. 11 , the dispense interface  200  is coupled to the distal end of a cartridge housing  40 . This cartridge holder  40  is illustrated as containing the first cartridge  90  containing the primary medicament  92  and the second cartridge  100  containing the secondary medicament  102 . Once coupled to the cartridge housing  40 , the dispense interface  200  essentially provides a mechanism for providing a fluid communication path from the first and second cartridges  90 ,  100  to the common holding chamber  280 . This holding chamber  280  is illustrated as being in fluid communication with a dose dispenser. Here, as illustrated, this dose dispenser comprises the double ended needle assembly  400 . As illustrated, the proximal end of the double ended needle assembly is in fluid communication with the chamber  280 . 
         [0097]    In one preferred arrangement, the dispense interface is configured so that it attaches to the main body in only one orientation, that is it is fitted only one way round. As such as illustrated in  FIG. 11 , once the dispense interface  200  is attached to the cartridge holder  40 , the primary needle  240  can only be used for fluid communication with the primary medicament  92  of the first cartridge  90  and the interface  200  would be prevented from being reattached to the holder  40  so that the primary needle  240  could now be used for fluid communication with the secondary medicament  102  of the second cartridge  100 . Such a one way around connecting mechanism may help to reduce potential cross contamination between the two medicaments  92  and  102 . 
         [0098]      FIG. 12   a - d  illustrate the production of a y-channel with GIT/WIT. It will only be described with respect to GIT, but the description can be used for WIT in an analogue manner. 
         [0099]    Turning first to  FIG. 12   a , one can see a device  300  comprising a mold  302 , and an injection site  304  for molten plastic and a second injection site  306  for gas. In this step of the production, molten plastic  308  is inserted via a first guide  312  into the mold  302 . The outer part of the molten plastic  308  starts to cool down while the inner part is being kept hot. Right before or right after the end of the molten plastic injection process, the gas injection via the guide  310  can start. The gas is preferably an inert gas, for example nitrogen. 
         [0100]    As illustrated in  FIG. 12   b , a y-channel  314  is formed within the molten plastic  308 , which is pushed to the walls of the mold  302  and solidifies as a plastic part  316 . After the plastic part  316  has cooled down, it can be taken out of the mold  302 . 
         [0101]    The produced plastic part  316  with the y-channel  314  as illustrated in  FIG. 12   c  has a first arm  318 , a second arm  320  and a third arm  322 . These three arms  318 ,  320 ,  322  each have an end  324 ,  326  and  328 , respectively. The two arms  318 ,  320  form an angle which is smaller than 180°. The third arm  322  extends away from said angle. The second arm  320  has at its end  326  an opening  330  due to the gas injection guide  310 . Along the lines  332 ,  334 ,  338  the ends  324 ,  326 ,  328  are cut off from the plastic part  316 . By this step all three ends  324 ,  326 ,  328  are opened. This cutting is preferably done with mechanical means, but it can also be done by laser cutting, for example. 
         [0102]    As can be seen in  FIG. 12   d  the three arms  318 ,  320 ,  322  of the plastic part  316  with the y-channel  314  have now defined openings  340 ,  342  and  344 , respectively. Through the openings  340  and  342  preferably two different medicaments  92 ,  102  can enter the y-channel  314  and through the opening  344  a mixture of the two medicaments  92 ,  102  can exit the y-channel  314 . 
         [0103]      FIG. 12   e  shows another exemplary embodiment of an apparatus according to the invention. Similar to the plastic part  316  shown in  FIG. 12   d , the plastic part  316 ′ shown in  FIG. 12   e  has three ends  324 ′,  326 ′,  328 ′, which have the openings  340 ′,  342 ′ and  344 ′, respectively. The plastic part  316 ′ can be produced in the same way as the plastic part  316 . In contrast to the plastic pat  316  shown in  FIG. 12   e , the ends  340 ′ and  342 ′ extend substantially parallel to each other. In this case they also extend parallel to the third end  328 ′, such that if the axis of the third end  328 ′ defines a downward direction, the first end  324 ′ and second end  326 ′ extend substantially in the upward direction. This further facilitates the manufacturing process. Moreover, this further facilitates the insertion of needles into the ends  324 ′ and  326 ′. 
         [0104]      FIG. 13  illustrates a cross-sectional view of a dispense interface  200  similar to the one illustrated in  FIG. 9 . The dispense interface  200  illustrated in  FIG. 13  shows the plastic part  316  and the y-channel  314  illustrated in  FIG. 12   d . The plastic part  316  is integrated via form fit into a first inner body  220 ′. Together with a second half of the inner body (not illustrated) the plastic part  316  can be fixed in between the inner bodies, for example. The inner body  220 ′ can then be attached to the main outer body  210  in the already described manner. 
         [0105]    The piercing needle  240  is attached to the opening  340  of the first arm  318  of the y-channel  314 . Accordingly the piercing needle  250  is attached to the opening  342  of the second arm  320  of the y-channel  314 . The attachment of the needles  240 ,  250  to the y-channel  314  can be realised by any appropriate method, for example form fit or force fit connections, or by adhesive bonding. The third opening  344  of the y-channel  314  is sealed by a pierceable septum  270 . Those features shown in  FIG. 13 , which are also shown in  FIG. 9 , are further described in connection with the description of  FIG. 9 .