Abstract:
A medicament delivery device is presented having a housing, and a medicament container holder arranged movable in a longitudinal direction in relation to the housing. The medicament container holder is arranged to accommodate a medicament container, is arranged as a multi-chamber container having a medicament and a diluent in different chambers, a plunger rod operably arranged to act on the medicament container, a retaining element capable of releasably retaining the plunger rod to the housing, actuation force elements capable of, upon activation, moving the medicament container holder in relation to the housing such that the plunger rod acts on the medicament container for mixing the medicament and the diluent.

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/EP2015/057827 filed Apr. 10, 2015, which claims priority to U.S. Provisional Patent Application No. 61/987,707 filed May 2, 2015 and Swedish Patent Application No. 1451313-9, filed Nov. 4, 2014. The entire disclosure contents of these applications are herewith incorporated by reference into the present application. 
     
    
     TECHNICAL AREA 
       [0002]    The present invention relates to a medicament delivery device capable of providing a function in which a dual chamber medicament container is handled in an efficient way without unnecessarily increasing the size of the device. 
       BACKGROUND 
       [0003]    There are liquid medicament compositions that degrade and lose their potency over time, before they can be administered to a patient. 
         [0004]    In order to handle these medicament compositions, so called multi chamber medicament containers have been developed. They often comprise elongated tubular containers divided by movable stoppers into a number of compartments or chambers, where the medicament in powder form is placed in one chamber and a diluent is placed in another chamber. At certain positions along the containers, passages are arranged, wherein, when the stoppers are moved, the passages are opened, allowing communication between the chambers and thus a mixing between the medicament and the diluent. The stoppers are often moved by an elongated plunger rod, which is often actuated by a drive spring. 
         [0005]    After mixing, a priming sequence is often necessary, in which air and gas entrapped in the medicament container after mixing needs to be removed. The stoppers have to be moved a short distance by the plunger rod in order to remove the air. The injection sequence is performed after mixing and priming. 
         [0006]    One problem with devices handling dual chamber medicament containers is that the devices tend to be rather long because the plunger rods have to be moved in the longitudinal direction of the devices both for priming, mixing and injection if the same drive springs are to be used for all the sequences. Also, a mechanical solution allowing the plunger rod to be actuated and stopped at several instances usually requires rather complex mechanisms. 
         [0007]    The document U.S. Pat. No. 8,323,238 discloses a medicament delivery device arranged to handle multi-chamber containers. However it contains only one drive spring and will therefore be rather long. Its length is not altered during use of the device. 
         [0008]    The document U.S. Pat. No. 8,123,719 discloses a medicament delivery device employing several drive springs in order to perform different required functions. However, the device is bulky and not intended for personal use by patients without medical training. 
       SUMMARY 
       [0009]    In the present application, when the term “distal part/end” is used, this refers to the part/end of the device, or the parts/ends of the members thereof, which under use of the device is located the furthest away from the medicament delivery site of the patient. Correspondingly, when the term “proximal part/end” is used, this refers to the part/end of the device, or the parts/ends of the members thereof, which under use of the device is located closest to the medicament delivery site of the patient. 
         [0010]    The aim of the present invention is to remedy the drawbacks of the state of the art devices. This aim is obtained with a medicament delivery device according to the independent patent claim. Preferable embodiments of the invention form the subject of the dependent patent claims. 
         [0011]    The medicament delivery device according to the invention comprises a housing. The housing is connected to a medicament container holder arranged movable in a longitudinal direction in relation to the housing. The medicament container holder is preferably arranged to accommodate a medicament container. The medicament container may be of a number of different types suitable for containing and delivering doses of medicament, but in the preferred solution the medicament container is arranged as a multi-chamber container comprising medicament and diluent in separate chambers. 
         [0012]    The medicament delivery device may further preferably comprise a plunger rod operably arranged to act on the medicament container. The plunger rod is preferably elongated and sized to fit into the medicament container. The medicament delivery device may further be arranged with a retaining element capable of releasably retaining the plunger rod in relation to the housing. 
         [0013]    According to a favourable solution actuation force elements are arranged and capable of, upon activation, moving said medicament container holder in relation to said housing such that said plunger rod acts on said medicament container for mixing said medicament and said diluent. With this solution, the plunger rod does not move when a mixing sequence is performed. Instead the medicament container is moved in the distal direction of the device in relation to the plunger rod. Thus the drive force elements are separated from any drive elements usually connected and operable on the plunger rod. Further the device becomes considerably shorter after the mixing sequence. 
         [0014]    According to another favourable solution, the medicament delivery device may further comprise a drive force element operably connected to the plunger rod such that, when said retaining element is actuated for releasing the plunger rod, it is forced to act on the medicament container for expelling the mixed medicament through a medicament delivery member. Thus, a separate drive force element is arranged for the dose delivery sequence. This shortens the length of the device because two separate force elements are used for different operation sequences. 
         [0015]    Preferably, the plunger rod may comprise first stop elements co-acting with the retaining element and capable of holding the plunger rod in an initial position, and as well as second stop elements capable of stopping the plunger rod after a first distance in the longitudinal direction for performing mixing. The mixing sequence is thus performed and the plunger rod is stopped until the next sequence is to be performed. 
         [0016]    In that respect the plunger rod may comprise third stop elements capable of stopping the plunger rod after a second distance in the longitudinal direction for performing priming. Thus also a priming step is performed and the plunger rod is stopped until the next sequence is to be performed. 
         [0017]    In order to obtain said functions, the stop elements may comprise stop ledges arranged on an outer surface of the plunger rod, which stop ledges are arranged generally transversal to the longitudinal direction, where the stop ledges are arranged to interact with stop surfaces on the medicament container holder. Thus the outer surface of the plunger rod is used for realising the desired functional sequences. 
         [0018]    Further the stop surfaces may comprise fixed ledges arranged to move in longitudinally extending groove sections on the outer surface of said plunger rod. In that respect groove sections may be placed offset to each other in a circumferential direction of said plunger rod, and wherein an end surface of a groove section comprises said stop ledges. The grooves are readily obtained on the outer surface and when the grooves are arranged offset to each other the end surfaces of the grooves become natural stop ledges. 
         [0019]    The plunger rod may be rotatable relative to the container holder in order to shift the fixed ledges from one groove section to a subsequent groove section. A user may, for instance, rotate the plunger rod by turning an knob, arranged on the medicament delivery device. 
         [0020]    Further, the medicament delivery device may comprise a manually operable activation element, operably connected to said retaining element for releasing said plunger rod when activated. The retaining element may comprise ledges arranged to fit into a groove segment of said plunger rod and to contact a stop ledge for holding said plunger rod. 
         [0021]    Also, the manually operable activation element may comprise release elements operably arranged to move said ledges of said retaining element out of contact with said stop ledge for releasing said plunger rod. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0022]    In the following detailed description of the invention, reference will be made to the accompanying drawings, of which 
           [0023]      FIG. 1  is an exploded view of a medicament delivery device, 
           [0024]      FIG. 2  is a longitudinal cross-sectional view of the device of  FIG. 1 , 
           [0025]      FIGS. 3-7  are detailed views of components comprised in the medicament delivery device of  FIG. 1 , and 
           [0026]      FIGS. 8-13  are detailed functional views of different steps. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The medicament delivery device shown in the drawings comprises a housing  10 ,  FIG. 2 , having a distal end  12  and a proximal end  14 . At the proximal end a central passage  16  is arranged,  FIG. 2 b   . In the central passage  16  a generally tubular medicament container holder  18 ,  FIG. 2 b   , extends in the proximal direction. The proximal part  20  of the medicament container holder  18 ,  FIG. 3 , is surrounded by a coaxial retainer sleeve  22 . Both the medicament container holder  18  and the retainer sleeve  22  are arranged with windows or openings  24  and  26 , through which a medicament container  28  may viewed. In the embodiment shown the medicament container  28  is a so called dual chamber container wherein a first chamber  30  is contains a medicament in dry form while the second chamber  32  contains diluent. The chambers are separated by a first movable stopper  34 . Further the distal end of the medicament container is arranged with a second movable stopper  36 . 
         [0028]    The medicament container is retained in the medicament container holder by a medicament container retainer  38  attached to the proximal end thereof such that the neck of the medicament container may extend through a tubular neck  40  of the medicament container retainer  38 . The neck  40  is arranged with suitable fastening elements capable of cooperating with mating fastening elements arranged on a medicament delivery member  42 ,  FIG. 2 . The fastening elements could comprise threads as shown, or bayonet connections or luer connections, just to mention a few. The medicament container retainer  38  is attached to the medicament container by distally directed tongues  44  extending into the medicament container holder. The free ends of the tongues  44  are arranged with outwardly extending ledges  46 , which ledges  46  are arranged to fit into and lock with grooves  48  on an inner surface of the medicament container holder  18 ,  FIG. 3 . 
         [0029]    At the distal end of the medicament container holder  18  an end plate  50 ,  FIG. 4 , is attached or made integral with the medicament container holder. The end plate  50  extends generally transversally with two oppositely positioned support plates  52 ,  FIG. 3 . These support plates  52  are in turn made rigid with support walls  54  extending in the proximal direction and attached to the support plates  52  as well as to the outer side surface of the medicament container holder  18 . The support plates  52  are further arranged with through holes  56 , in which attachment posts of guide rods  58  for actuation force elements  60  may be attached,  FIGS. 1 and 2 . These elements  60  are in the embodiment shown two compression springs that are tensioned between the end plates  52  and a distally directed wall surface  62  of the housing  10 ,  FIG. 2   b.    
         [0030]    Further the distal end of the medicament container holder  18  is arranged with a central passage  64 ,  FIG. 4 . The central passage  64  is arranged with radially inwardly directed, generally rectangular ledges  66 . These ledges  66  are intended to cooperate with longitudinal grooves  68  of a plunger rod  70 ,  FIG. 5 . The plunger rod  70  is arranged to extend into the medicament container holder  18  and to act on the second stopper  38  as seen in  FIG. 2 b   . Further, as seen in  FIG. 5 , the grooves of the plunger rod are divided into sections. A first section  68   I  at the proximal end of the plunger rod  70  ends with a proximally directed first stop ledge  72   I . A second section  68   II  is connected to the first section  68   I  and arranged offset in the circumferential direction in relation to the first section  68   I . The second section  68   II  ends with a proximally directed second stop ledge  72   II  at a distance d II , from the first stop ledge  72   I , along the plunger rod  70 . A third section  68   III  connects to the second section  68   II . The third section  68   III  is arranged offset in relation to the second section. The third section  68   III  has a shorter distance d III  in relation to the second section  68   II  and ends with a third stop ledge  72   III . A fourth section  68   IV  connects to the third section  68   III , positioned offset in the circumferential direction. The fourth section  68   IV  ends at a distance d IV  at the distal end of the plunger rod  70  with a fourth stop ledge  72   IV . 
         [0031]    Further, a retaining element in the form of a release tab  74 ,  FIG. 5 , is provided that is intended to interact with the grooves  68  of the plunger rod and in particular the fourth section  68   IV  and its stop ledge  72   IV  as will be described below. The release tab  74  has a generally ring-shaped body  76  with two arms  78  extending in the proximal direction, where the arms  78  are positioned opposite each other on the body  76 . The arms  78  are further arranged with radially inwardly directed ledges  80  that are arranged to fit into the fourth section  68 IV of the grooves. In that position of the arms  78  there is a distance d V ,  FIG. 2 a   , in the radial direction to the inner wall of the housing  10 . Further, an activation element in the form of a push button  82 ,  FIG. 5 , is arranged distally of the release tab  74 . The push button  82  is arranged with two proximally extending arms  84 . The free ends of the arms  84  are arranged with generally outwardly directed protrusions  86 , which protrusions are arranged to be in contact with inner surfaces of the arms  78  of the release tab  74 . The push button is further arranged with two guide arms  88  extending in the proximal direction. 
         [0032]    Both the release tab  74  and the push button  82  are arranged in a generally tubularly shaped knob  90 ,  FIG. 6 , arranged at the distal end of the medicament delivery device. The knob  90  is arranged with a generally transversal end wall  92 ,  FIG. 7 . The end wall  92  is arranged with passages  94  through which the arms  84 ,  88  of the push button  82  extend. Further the ring-shaped body  76  of the release tab  74  is attached to a proximally directed surface of the end wall  92 , as seen in  FIG. 6 . The end wall  92  of the knob  90  is arranged with a central post  95 ,  FIG. 7 , having a proximally directed support surface  96 . A plunger rod drive spring  98   FIGS. 1 and 2 , is arranged between the support surface  96  of the knob and a distally directed surface of an end wall  100 ,  FIG. 2 , of the plunger rod  70 . 
         [0033]    The proximal end of the knob  90  is further arranged with an outwardly directed circumferential ledge  102 . The ledge  102  is designed with a zig-zag-shaped surface that is intended to cooperate with a correspondingly zig-zag-shaped surface  104 ,  FIG. 7 , on a proximally directed circumferential ledge arranged in a central passage  106  of an end cap  108  of the housing  10 . The central passage  104  is arranged such that the knob  90  can extend there-through in the distal direction. The end cap  108  is attached to the housing by suitable means such as glue, welding, snap-in elements etc. 
         [0034]    The end cap  108  is further arranged with proximally directed posts  110 , which posts are arranged to come in contact with the distally directed surfaces of the support plates  52  of the medicament container holder  18 . Further, a blocker plate  112  is arranged to the end cap  108 ,  FIG. 6 . It comprises a hub  114  intended to be placed in the central passage  104  and it is rotationally locked to the end plate  108  by generally radially extending tabs  116  that fit into recesses  118  on the edge of the central passage  104 . The blocker plate  112  is also arranged with a central passage  120  through which the plunger rod  70  may extend. Around the circumference of the central passage  120  a number of distally directed stop ledges  122  are arranged, which are arranged to interact with the arms  78  of the release tab  74  such as to limit rotational movement of the knob  90  and the release tab  74 . 
         [0035]    The blocker plate  112  is held in position in the end cap  108  by a blocker plate nut  124 . It comprises a ring-shaped body  126  arranged with thread segments  128  on its outer surface. These tread segments  128  are arranged to interact with corresponding inclined grooves  130  on an inner surface of the central passage  104  of the end cap  108 . The blocker plate nut  124  is locked in position by generally circumferentially extending flexible arms  130  that fit into the recesses  118  of the end cap  108  when the blocker plate nut is in its locking position. 
         [0036]    The device is intended to function as follows. The device is delivered to the user as seen in  FIG. 2 . The device is loaded with a medicament container  28 . The medicament container holder  18  extends in the proximal direction out of the housing  10 . The actuation springs  60  are compressed and the medicament container holder  18  is held in that state in relation to the housing  10  in that the ledges  64  in the central passage of the medicament container holder  18  are abutting the first stop ledges  72   I  of the plunger rod  70  as seen in  FIG. 8 . The plunger rod  68  is in turn held in position by the ledges  80  of the release tab  74  being positioned in the fourth section  72   IV  and abutting the fourth stop ledge  72   IV  as seen in  FIG. 9 . The drive spring  98  of the plunger rod  70  is tensioned, as seen in  FIG. 2 . 
         [0037]    The first step is to mix the medicament and the diluent in the medicament container  28 . The user then turns the knob  90  a number of steps that are caused by the zig-zag surfaces  104  between the knob  90  and the medicament container holder  18 . The ledges  66  of the central passage  64  are then moved into the second section  68   II  of the groove  68  plunger rod  70 . The medicament container holder  18  with its medicament container  28  is now free to move in the distal direction due to the actuation springs  60 . Since the plunger rod  70  is stationary it will act on the stoppers  34 ,  36  inside the medicament container  28  whereby the medicament will mix with the diluent. The movement is stopped when the ledges hit the second stop ledges  66   II ,  FIGS. 10 and 11 . 
         [0038]    After the mixing, the user then attaches a medicament delivery member  42  to the proximally directed neck  40  of the medicament container retainer  38 . In the embodiment shown an injection needle is attached. Due to the mixing, the medicament container  28  has to be primed in order to remove any air or gas trapped inside. The user then turns the knob  90  further steps, whereby the ledges  66  will enter the third section  68   III  and the medicament container holder  18  and the medicament container  28  now moves the distance d III ,  FIG. 12 , which causes the plunger rod  70  to act on the stoppers  34 ,  36 , thereby removing any residual air. 
         [0039]    The device is now ready for delivering a dose of medicament. The user presses the proximal end of the device against a dose delivery site and in the present embodiment, a penetration is performed. In order to start the injection sequence, the knob  90  is turned further steps whereby the ledges  66  will be moved into the fourth section  68   IV . However, now the medicament container holder  18  cannot move further in the distal direction because the distally directed surface of the medicament container holder  18  is in contact with the posts  110  of the end cap  108 . The user therefore presses the push button  82  in the proximal direction, which causes the protrusions  86  of the arms  84  of the push button  82  to press on the arms  78  of the release tab  74  such that its ledges  80  are moved out of contact with the fourth stop ledge  72   IV  of the fourth section  68   IV  on the plunger rod  70 . The plunger rod  70  is now urged in the proximal direction by the drive spring  98 , which in turn causes the stoppers  34 ,  36  to be moved in the proximal direction, wherein a dose of medicament is delivered through the medicament delivery member  42 ,  FIG. 13 . When the injection sequence is completed, the device may be removed from the dose delivery site and discarded in a safe way, possibly also by removing and recapping the injection needle if such is used. 
         [0040]    It is to be understood that the embodiment described above and shown in the drawings is to be regarded only as non-limiting examples of the invention and that it may be modified in many ways within the scope of the patent claims.