Abstract:
A medicament delivery device includes a housing arranged to receive a medicament container, a drive unit arranged to act on a stopper in the medicament container, which drive unit includes a torsion drive spring. A dose setting member is operably connected to the drive unit such that a manual turning of the dose setting member causes a tensioning of the torsion drive spring. The device also includes an activation mechanism having an activation button protruding through a distal end of the device. The activation mechanism is operably connected to the drive unit such that actuation of the activation mechanism causes a release of the drive unit, with a set dose of medicament delivered.

Description:
TECHNICAL AREA 
     The present invention relates to a medicament delivery device and in particular a medicament delivery device utilizing multi-chamber medicament containers that require mixing before drug delivery to a patient. 
     BACKGROUND OF INVENTION 
     It is becoming more and more common to use multi-chamber medicament containers in medicament delivery devices such as injectors. The reason for this is that the medicament can be stored for much longer time periods without being degraded in comparison with medicament dissolved in some liquid. 
     Thus the medicament and the liquid are kept in different compartments in the medicament container and are mixed just before use by moving a dividing wall or stopper such that the compartments can communicate with each other. 
     However, the multi-chamber medicament containers entail more handling steps before a dose of medicament can be injected in that the plunger rod of the injector has to move the stopper or stoppers of the medicament container in order to initiate the mixing. 
     Another feature of many medicament delivery devices and in particular injectors is the attachment of a medicament delivery member, in particular an injection needle to a medicament container and then how to avoid unintentional needle sticks. Document WO2010/000559 discloses a medicament delivery device utilizing a multi-chamber medicament container where the mixing is obtained by rotating a medicament container holder, positioned in the proximal housing part, into a distal housing part whereby the stopper of the medicament container is moved against a plunger rod. In the initial position the proximal end of the medicament container is protruding beyond the proximal housing part, where the latter also acts as a needle shield, such that a medicament delivery device can be attached to the medicament container holder. When the mixing has been performed, the medicament delivery member is drawn into the proximal housing/needle shield. The needle shield is now used for actuating the device in that when a penetration is performed, the needle shield is pushed in the distal direction, whereby it triggers an auto-injection sequence. Thus the needle shield assembly extends almost to the distal end of the device in order to be able to actuate the injection. 
     However, for some devices it is neither necessary nor desirable to have so many components and functions since they tend to make the devices more complex and more expensive. Also the holding of the device during mixing may be performed with one hand rather close to the proximal end of the device instead of the distal end of the device. There is thus room for development of medicament delivery devices. 
     BRIEF DESCRIPTION OF INVENTION 
     The aim of the present invention is to provide a medicament delivery device that can handle multi-chamber medicament containers in a simple and intuitive but yet safe way. 
     According to a main aspect of the invention it is characterised by a medicament delivery device according to the features of the independent patent claim. Preferable embodiments of the invention form the subject of the dependent patent claims. 
     According to a main aspect of the invention it is characterised by a medicament delivery device comprising a body which comprises a housing and a medicament container holder accommodating a multi-chamber medicament container, wherein said housing and said medicament container holder are interactively connected to and movable relative each other; the medicament container holder comprising attachment means for attaching a delivery member; a mixing guard mechanism interactively connected to the body for driving the medicament container holder within the housing and thereby achieving a reconstitution wherein the mixing guard mechanism comprises a mixing cylinder unit and a tubular medicament delivery member guard operably connected to the medicament container holder, such that when the mixing cylinder unit is operated, the medicament container holder is moved in relation to the medicament delivery member guard between a pre-mix position in which said attachment means protrudes through a proximal end of said medicament delivery member guard for allowing the attachment of a delivery member and a mixed position in which said attachment means and said attached delivery member is positioned within the medicament delivery member guard, wherein said mixing guard mechanism further comprises a guard lock and release member operably connected to said guard and to said medicament container holder, such that said guard lock and release member is configured to lock said guard when the container holder is in the pre-mix position and to release said guard when the container holder is moved to the mixed position. 
     According to another aspect of the invention movement in the distal direction of the guard member, when the device is pressed against a dose delivery site, causes a turning of a rotator member comprised in said mixing cylinder unit. 
     According to further aspect of the invention said turning is caused by said rotator member comprising at least one groove inclined in relation to the longitudinal direction of the device, cooperating with at least one protrusion arranged on the guard during distal movement of said guard. 
     According to yet another aspect of the invention said mixing guard mechanism further comprises a resilient member operably arranged to said guard for urging said guard in the proximal direction. 
     According to yet a further aspect of the invention the rotator member comprises a first guard locking means interactively connected to the rotator member such that proximal movement of said guard, after removal from a medicament delivery site, causes a locking of said guard in a proximal position covering said medicament delivery member. 
     According to another aspect of the invention said mixing guard mechanism comprises first connection means, interactively connecting said housing and said medicament container holder for allowing the medicament container holder to be displaced within the housing. 
     According to a further aspect of the invention said first connection means comprises cooperating threads on said housing and said medicament container holder. 
     According to yet another aspect of the invention said first guard locking means comprises at least one proximally directed resilient tongue arranged to said rotator member and at least one protrusion arranged to said guard such that when said guard is proximally displaced, said at least one protrusion passes said at least one tongue, thereby preventing subsequent distal displacement of said guard. 
     According to yet a further aspect of the invention said medicament container holder and said guard are slidably connected but rotationally locked to each other by second connection means. 
     According to another aspect of the invention said mixing cylinder is arranged to said guard such that they are slidably connected but rotationally locked to each other by third connection means. 
     According to a still further aspect of the invention said mixing cylinder and a connector sleeve are fixedly connected to each other by fourth connection means. 
     According to yet another aspect of the invention said connector sleeve and said housing are connected to each other by fifth connection means which prevent a longitudinal movement in relation to each other but allow rotation in relation to each other. 
     According to a further aspect of the invention said rotator member and said connector sleeve are connected to each other by sixth connection means which prevent a longitudinal movement in relation to each other but allow partial rotation in relation to each other, and wherein said connector sleeve and said rotator member are coaxially arranged within said mixing cylinder. 
     According to yet a further aspect of the invention said rotator member and said mixing cylinder are one-direction-rotatably connected to each other by seventh connection means. 
     According to another aspect of the invention it further comprises drive means arranged within said housing and adapted to drive a stopper positioned within said multi-chamber container. 
     According to yet another aspect of the invention said drive means comprises a plunger rod and a force member operatively acting on said plunger rod for urging it in the proximal direction. 
     According to a further aspect of the invention it further comprises a holding means for holding said drive means in a pre-tensioned state. 
     According to yet a further aspect of the invention it comprises activation means capable of acting on said holding means for releasing the drive means from the pre-tensioned state 
     According to another aspect of the invention the device is an injection device. 
     There are several advantages with the present invention. The use of a tubular medicament delivery member guard operatively connected to the medicament container holder and the mixing means provides the possibility of attaching a medicament delivery member to the device and then during the mixing operation cover the medicament delivery member by activating the tubular guard member. By using a rotator member, several functions of the device are obtained with few components and provides the interaction of functions. 
     Further the mixing guard mechanism enables a pushing of the tubular guard in the distal direction when the device is pressed against a dose delivery site. This movement of the tubular guard causes components of the mixing guard mechanism to be moved and thus prepared for a locking of the tubular guard member when the device is removed from the dose delivery site after completed dose delivery, wherein the tubular guard is pushed in the proximal direction by the spring force, thereby surrounding the medicament delivery member in a locked state, whereby the medicament delivery member cannot be tampered with. 
     These and other aspects of, and advantages with, the present invention will become apparent from the following detailed description of the invention and from the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       In the following detailed description of the invention, reference will be made to the accompanying drawings, of which 
         FIG. 1  is a perspective view of a medicament delivery device according to the present invention, 
         FIG. 2  is a cross-sectional view in perspective of the device of  FIG. 1 , 
         FIG. 3  is an exploded view of the device of  FIG. 1 , 
         FIG. 4  is a detailed exploded view of a medicament delivery member guard and a proximal housing part, 
         FIG. 5  is a detailed exploded view of key components of the present invention, 
         FIG. 6  is the same view as  FIG. 4  turned 180°, 
         FIG. 7  is a detailed cross-sectional view in of a proximal part of the device of  FIG. 1 , 
         FIG. 8  is a detailed view of a component comprised in the present invention, and 
         FIGS. 9-13  are cross-sectional views in perspective, partly in detail, displaying different functional states. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the present application, when the term “distal part/end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which is/are located the furthest away from the medicament delivery site. Correspondingly, when the term “proximal part/end” is used, this refers to the part/end of the delivery device, or the parts/ends of the members thereof, which, is/are located closest to the medicament delivery site. 
     The medicament delivery device shown in the drawings comprises a body, which in turn comprises a generally elongated housing  10  and a generally tubular medicament container holder  12 ,  FIG. 3 . The proximal end of the medicament container holder comprises a neck portion  14  onto which a medicament delivery member  16  may be releasably attached. The interior of the medicament container holder is arranged to house a multi-chamber medicament container  18 , having a proximal end fitting into the neck portion  14  of the medicament container holder  12 . The interior of the medicament container  12  contains a number of movable stoppers  20 ,  22 , which stoppers form a number of chambers  24 ,  26  containing medicament in powder form and a diluent. 
     A drive mechanism is further arranged in the housing, comprising an elongated plunger rod  28  having a proximal end in contact with the stopper  20  at the distal end of the medicament container  12 . The plunger rod  28  is operatively connected to a drive force member  30  of the drive mechanism operatively acting on the plunger rod  28  for urging it in the proximal direction. The device further comprises a holding member  32  capable of holding the drive force member  30  in a pre-tensioned state as well as an actuation member  34  capable of acting on said holding member  32  for releasing the drive force member  30  from the pre-tensioned state,  FIG. 2 . The actuation member  34  comprises an actuation button  36  extending through a distal end of the housing. 
     The device further comprises a mixing guard mechanism arranged for mixing the content of the chambers of the multi-chamber medicament container. Thereby the housing  10  and the medicament container  12  are interactively connected to each other by first connection means for allowing the medicament container holder to be displaced within the housing. The first connection means comprises threads  38  on the outer surface of the medicament container holder  12 , which threads  38  cooperate with corresponding threads  40 ,  FIG. 2 , on the inner surface of the housing  10 . The mixing means further comprises longitudinally extending grooves  42 ,  FIG. 3 , on the outer surface of the medicament container holder  12 , which grooves  42  cooperate with corresponding ribs  44 ,  FIG. 5 , on an inner surface of a generally tubular medicament delivery member guard  46 , forming second connection means. Further a guard member lock and release member is arranged wherein the outer surface of the medicament container holder  12  at its proximal end is arranged with two oppositely positioned outwardly directed protrusions  49 ,  FIG. 4 . These protrusions  49  are arranged to fit into longitudinal slits or grooves  48  arranged in the medicament delivery member guard  46 . The medicament delivery member guard  46  is further arranged with a circumferential ledge  47  around the opening at the proximal end. The ledge is arranged to abut a proximal end surface  51  of the medicament container holder surrounding the neck portion  14 , thereby preventing movement of the medicament delivery member guard  46 . 
     Further the medicament delivery member guard  46  is arranged slidable inside a generally tubular mixing cylinder  50  but rotationally locked, via longitudinal grooves  52  on the outer surface of the medicament delivery member guard  46  cooperating with inwardly protruding ledges  54  on the proximal end of the mixing cylinder  50 ,  FIG. 6 , forming third connection means. The medicament delivery member guard  46  is urged in the proximal direction in relation to the mixing cylinder  50  by a spring member  56 ,  FIG. 7 , acting between a distal end surface of the medicament delivery member guard  46  and a proximal end surface of the housing  10 . 
     Further the mixing cylinder  50  is rotatably attached to the proximal end of the housing  10  via a connector sleeve  58  by a fourth connection means such that it fits into said mixing cylinder  50  and rotationally locked by ribs  57  on the outer surface of the connector sleeve  58  fitting into grooves  59  on the inner surface of the mixing cylinder  50 ,  FIGS. 5 ,  6 . The connector sleeve  58  is attached to the mixing cylinder by outwardly flexible tongues  60  fitting into recesses  62  on the inner surface of the mixing cylinder  50 ,  FIGS. 5 and 6 . The connector sleeve  58  is further arranged with a circumferential, inwardly extending ledge  64  in contact with a circumferential ledge  66  of the outer surface of the proximal end of the housing  10 , forming a fifth connection means. 
     Further a generally cylindrical rotator  68  is arranged rotatable inside said mixing cylinder  50  in its proximal end and held in place by the connector sleeve  58  with a sixth connection means. The proximal end surface of the rotator  68  is arranged with flexible tongues  70  extending along the circumference, which are provided with proximally directed wedge-shaped ledges  72 ,  FIG. 8 . The ledges  72  cooperate with wedge-shaped ratchets  74  on a distally directed surface of a circumferential ledge  76  of the mixing cylinder  50 , such that the rotator  68  can only rotate in one direction in relation to the mixing cylinder  50 , forming seventh connection means. 
     The rotator  68  is further arranged with proximally directed, and inwardly flexing, tongues  78  having proximally directed end surfaces  79 ,  FIG. 8 , which tongues  78  are arranged in grooves  80  on the inner surface of the rotator  68 , which grooves  80  extend in the longitudinal direction of the device, forming eighth connection means. Further the longitudinal grooves  80  are cooperating with inclined grooves  82  that meet at the distal end of the longitudinal grooves  80 , the function of which will be described below. Protrusions  84  are further arranged on the outer surface of the medicament delivery member guard  46 , which protrusions  84  are arranged to cooperate with the grooves  80 ,  82  of the rotator  68 , as will be described below. 
     The device is intended to function as follows. When the device is delivered to a user, the proximal end of the medicament container holder  12  protrudes through the proximal end of the medicament delivery member guard  46 ,  FIG. 2 . This enables a medicament delivery member  14  to be attached to the proximal end of the medicament container holder  12 . In this position the proximal end surface  51  of the medicament container holder  12  is in contact with the circumferential ledge  47  of the medicament delivery member guard  46 , whereby the latter is locked against distal movement,  FIG. 9 . After a medicament delivery member  16  has been attached, the next step is to perform the mixing. This is performed by rotating the mixing cylinder  50  in relation to the housing  10 . This causes the medicament container holder  12  to be moved in the distal direction because of the threads  38  of the medicament container holder  12  cooperating with the threads  40  of the housing. The distal movement of the medicament container holder causes the medicament delivery member  14  to be moved into the medicament delivery member guard  46 ,  FIG. 10 . The protrusion  49  on the container holder  12  will slide in the groove  48  of the medicament delivery member guard  46  until the container holder and thus the proximal end of the medicament delivery member has reached a certain distance in relation to the proximal end of the guard  46 ,  FIG. 11 , which also releases the guard such that it is movable in the longitudinal direction against the force of the spring member  56 . In this position the protrusions  49  will come in contact with the distal end of the grooves  48  whereby the guard  46  will also be moved in the distal direction until the mixing sequence has been completed. 
     The next step is to press the proximal end of the device against the medicament delivery site, such an injection site. The pressing of the device causes the medicament delivery member guard  46  to be pushed in the distal direction into the device and against the force of the medicament delivery member guard spring drive member  56 , thereby exposing the medicament delivery member  16 . The distance that the container holder  12  and its medicament delivery member  16  have been previously moved distally in relation to the guard, i.e. the length of the groove  48 , correspond to a desired and set injection depth when the medicament delivery member is an injection needle. 
     The distal movement of the medicament delivery member guard  46  causes its protrusions  84  to slide along the side surfaces of the inclined grooves  82  whereby the rotator  68  is turned. When the device is fully pressed against the delivery site, the medicament delivery mechanism is activated and a dose of medicament is delivered through the medicament delivery member  16 ,  FIG. 12 . Thus, when the actuation button  36  is pressed, the lock member releases the drive member for delivering a dose. However, instead of an automatic dose delivery function, there could instead be a purely manual dose delivery function such that the actuation button acts directly on the plunger rod, whereby the latter is pushed in the proximal direction when the actuation button is pressed. Also, the device may be provided with some kind of actuation locking and release means which acts to keep the actuation mechanism locked until a mixing operation is completed, in order to avoid unintentional activation until the device is ready for use. 
     When a dose of medicament has been delivered, the device may be withdrawn from the site. This causes the medicament delivery member guard  46  to be again pushed in the proximal direction, whereby its protrusions  84  slide along the longitudinally directed grooves  80  of the rotator  68  until the protrusions  82  slide over and pass the tongues  78 , after which the medicament delivery member guard  46  is covering the medicament delivery member. This will lock the medicament delivery member guard  46  against being pushed again in the distal direction in that its protrusions  84  will come in contact with the proximal end surfaces  79  of the tongues  78 , which, in the case when the medicament delivery member is an injection needle, prevents unintentional needle sticks,  FIG. 13 . The device may now be discarded. 
     It is to be understood that the embodiment described above and shown in the drawings is to be regarded only as a non-limiting example of the invention and that it may be modified in many ways within the scope of the patent claims.