Patent Description:
There is a constant development of medicament delivery devices that are intended and designed to be used and handled by users that are not qualified nursing staff or physicians, i.e. handled by the patients themselves. The applicant of the present invention has developed a large number of medicament delivery devices that display a high degree of automated functions comprising mixing of drug, priming, penetration, injection withdrawal and/or extension of medicament delivery member guard.

In order to create a number of these functions while keeping the number of components as low as possible, a so called rotator has often been utilized, which is a generally tubular element that is capable of rotating inside the housing of a medicament delivery device, where the rotation triggers, enables and/or performs different functions.

Document <CIT> discloses a safety device for injection devices in which the user can easily initiate an injection and at the same time activate the safety device for a needle protection device.

Document <CIT> discloses a medicament delivery device arranged with such a rotator. The rotator is operated by a medicament delivery member guard during penetration sequence. The rotator in turn affects holding elements that holds a plunger rod in a tensioned state. The holding elements are in the form of arms provided with inwardly directed protrusions fitting into recesses of the plunger rod.

Even though the rotator solution works very well in most instances and provides a reduced number of components as compared to more conventional solutions, there have been occurrences when the rotational movement of the rotator has caused a bending of the holding members due to the friction between the rotator and the holding members. This in turn has led to a jamming of the holding members such that the plunger rod has not been released as it should.

The aim of the present invention is to remedy the drawbacks of the state of the art drive mechanisms. This aim is obtained by a medicament delivery device having the features of the independent patent claim. Preferable embodiments are found in the dependent patent claims.

The present invention relates to a medicament delivery device. The drive mechanism of the medicament delivery device comprises a plunger rod and a drive spring operably arranged to plunger rod wherein the plunger rod is arranged to act on a stopper arranged in a medicament container.

The drive mechanism may further be arranged with an actuator comprising a holding member releasibly engaged to the plunger rod for holding said plunger rod with said drive spring in a tensioned state. Also a rotator is operably connected and movable relative to said actuator and configured to interact with said holding member for holding said holding member in engagement with the plunger rod.

Further, an activator may be operably connected to the rotator, in that the activator is configured to rotate and subsequently linearly displace the rotator in relation to the actuator such that holding member is released from the plunger rod. With this solution it is possible to avoid the previous problems associated with the rotation of the rotator prior to unlocking of the actuator, because the final movement is a linear movement. The risk of jamming of the holding members is then avoided or at least substantially reduced.

In order to control the movement of the rotator, the actuator may be arranged with a guide surface on which the rotator rests when rotated from a first position to a second position. In order to further control the movement of the rotator, it may be arranged with a cut-out, in which the guide surface can enter in the second position for allowing a linear move of the rotator. Thus, in the rotational movement between the first and the second position, the rotator is guided by the guide surface, preventing any linear movement, and then in the second position, the linear movement is provided in that the guide surface enters the cut-out.

In order to provide a rotational movement, the rotator may comprise first guide ridges that are inclined in relation to a longitudinal direction, on which first guide ridges the activator acts for rotating said rotator. Thus the inclined surface provides the means for rotating the rotator from the first position to the second position.

The rotator may further comprise second guide ridges interconnected to the first guide ridges, wherein the second guide ridges are generally transversal in relation to the longitudinal direction, on which second guide ridges the activator may act for moving said rotator.

In order to obtain the right relative initial positions between the rotator and the actuator, the rotator may comprise first orientating elements operably arranged to interact with second orientating elements on the actuator for providing orientation aid when the rotator is assembled with the actuator.

According to one feasible solution, the first orientating elements may comprise longitudinal grooves and wherein the second orientating elements comprise protrusions arranged to fit into the longitudinal grooves. This enables a proper orientation when the rotator is pushed onto the actuator during assembly of the drive mechanism, reducing the risk of rotational misalignment of the rotator in relation to the actuator.

In order to further provide aid when assembling the drive mechanism, it may further comprise a stop recess on the rotator, in which stop recess the protrusion would fit when the rotator is attached to the actuator. This gives a clear indication that the rotator has been pushed onto the actuator properly. This may also be used as a stop member in the opposite direction, i.e. preventing pulling off of the rotator from the actuator.

According to one feasible solution, the activator may comprise a medicament delivery member guard. Since the medicament delivery member guard is arranged at the proximal end of a medicament delivery device, it may move distally when the medicament delivery device is pressed against a dose delivery site, which movement may be used for rotating and moving the rotator.

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.

In the following description, the wording medicament delivery device will be used. In this context, medicament delivery devices may include a number of devices capable of delivering certain doses of medicament to a user, such as e.g. injection devices with or without injection needles, inhalers of all kinds, such as powder, aerosol driven, gas, nebulizers having mouth or nasal pieces, dispensers for medicament in tablet form, eye dispensers, crème/gel dispensers, etc. The medicament delivery devices may be of either disposable type or re-usable type and may be provided with medicament containers suitably arranged for specific drugs in specific forms.

Further, the term "distal part/end" 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 a delivery site of a patient. Correspondingly, the term "proximal part/end" 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 delivery site of the patient.

The medicament delivery device shown in the drawings comprises a generally tubular elongated housing <NUM> having a distal end <NUM> and a proximal end <NUM>, <FIG>. The housing <NUM> is further arranged with windows or openings <NUM>, through which a medicament container <NUM> can be viewed. The medicament container <NUM> is arranged with a movable stopper <NUM>. The device further comprises a medicament container holder <NUM> having a generally tubular shape, <FIG>. The medicament container holder <NUM> is arranged to accommodate the medicament container <NUM>, where the medicament container <NUM> has a proximal end on which a medicament delivery member <NUM>, <FIG>, is arranged, either made integral or connectable to the medicament container <NUM>. The medicament delivery member <NUM> is preferably protected before use by a medicament delivery member shield <NUM> that in the embodiment shown is a so called rigid needle shield or RNS. It is however to be understood that other types of medicament delivery member shields may be used in order to obtain the desired protection of the medicament delivery member <NUM>.

The proximal end of the housing is arranged with a central passage <NUM>, <FIG>, through which an activator <NUM> extends. In the present embodiment the activator <NUM> is a generally tubular medicament delivery member guard. The medicament delivery member guard <NUM> is in this embodiment an activation mechanism of a drive mechanism comprised in the medicament delivery device. It is arranged slidable i.e. linearly movable in relation to the housing <NUM> such that the housing <NUM> with the medicament container <NUM> and the medicament delivery member <NUM> are moved in the proximal direction when the medicament delivery device is pressed against a dose delivery site, thereby exposing the medicament delivery member <NUM> such that a penetration is performed when the medicament delivery member is an injection needle.

The activator <NUM> comprises a proximal tubular <NUM> part and two distally directed arms <NUM> extending from the tubular part <NUM>. A medicament delivery member guard spring <NUM> is arranged between a distally directed circumferential wall part of the activator <NUM> and a proximally directed circumferential surface of the housing. The arms <NUM> are arranged slidable along the medicament container holder <NUM>. At the distal end of the arms <NUM>, inwardly directed protrusions <NUM> are arranged. The protrusions <NUM> are arranged to operably interact with a rotator <NUM>, <FIG> and <FIG>, of a drive mechanism comprised in the medicament delivery device, when the activator30 is moved in relation to the housing, wherein the rotator <NUM> is positioned distally of the medicament container <NUM>.

The rotator <NUM> has a generally tubular shape and is arranged with guide ridges <NUM>, <FIG>, that are intended to cooperate with the protrusions <NUM> of the activator <NUM>. The guide ridges comprise a first guide ridge <NUM>i that is inclined in relation to the longitudinal axis L of the device, which inclined first guide ridge interconnects with a rounded second guide ridge <NUM>r as seen in <FIG> where the second guide ridge <NUM>r is generally transversal to the longitudinal axis L. A third guide ridge <NUM>l is connected to the second guide ridge, where the third guide ridge <NUM>l is extending in the longitudinal direction. The functions of the guide ridges will be described below. Adjacent the third guide ridge <NUM>l are proximally directed tongues <NUM>, which tongues <NUM> are arranged with wedge-shaped outwardly directed ledges <NUM>. Further, the rotator is arranged with cut-outs <NUM> at its distal end surface. Inside the rotator, support surfaces <NUM> are arranged. Further inside the rotator <NUM>, orientating elements in the form of longitudinal grooves <NUM> are arranged, from a distal end to almost the proximal end. However, the groove <NUM> terminates a distance from the proximal end. At the edge of the proximal end in the direction of the longitudinal groove a cut-out <NUM>, forming a stop recess, is made.

An actuator <NUM>, <FIG> and <FIG>, is in this embodiment a part of the drive mechanism comprised in the medicament delivery device, The actuator <NUM> is further arranged operably to the rotator <NUM>. It comprises a first proximal tubular section <NUM> having a diameter slightly smaller than the inner diameter of the rotator <NUM>. It further comprises a second section <NUM> arranged to fit into and to be attached to a distal part of the housing <NUM>. The second section <NUM> is provided with proximally directed ledges <NUM> arranged to interact with the rotator as will be described. The second section is further arranged with proximally directed stop surfaces <NUM>, <FIG>.

The first section <NUM> is further arranged with holding members <NUM> which in the present embodiments are proximally extending arms that are arranged flexible in a generally radial direction. The free ends of the holding members <NUM> have outwardly extending protrusions <NUM> that are to interact with the guide surfaces <NUM> of the rotator <NUM> as will be described. Further the free ends of the holding members <NUM> are arranged with inwardly extending protrusions <NUM>, which protrusions <NUM> are intended to interact with recesses <NUM> on a generally tubular plunger rod <NUM>, <FIG>. The generally tubular plunger rod <NUM> is in this embodiment a part of the drive mechanism comprised in the medicament delivery device. The protrusions <NUM> extend into a central passage <NUM> of the actuator <NUM>, in which passage <NUM> the plunger rod <NUM> fits. Further, outwardly directed, generally wedge-shaped, protrusions <NUM> are arranged adjacent the passage <NUM>.

A drive spring <NUM> which is in this embodiment a part of the drive mechanism comprised in the medicament delivery device, is placed inside a cavity of the hollow plunger rod <NUM>, wherein the drive spring <NUM> is positioned with a proximal end thereof in contact with an end wall <NUM> of the plunger rod <NUM>, <FIG>. The distal end of the drive spring <NUM> is in contact with a generally U-shaped element, hereafter named activator <NUM>, having a base <NUM> and two arms <NUM>, <FIG>. The arms <NUM> of the activator <NUM> are directed in the proximal direction along, and in contact with, the outer surface of the plunger rod <NUM>, wherein the free ends of the arms <NUM> are arranged with generally radially outwardly directed ledges <NUM>. These ledges <NUM> are arranged to be in contact with a proximally directed surface <NUM>, <FIG>, surrounding the central passage <NUM> of the actuator <NUM>.

The medicament delivery device is further arranged with a protective cap <NUM>, <FIG> and <FIG>, having a shape as to be releasibly attached to the proximal end of the housing. The protective cap <NUM> is further arranged with a medicament delivery member shield remover <NUM> that in the embodiment shown has a generally tubular shape with a diameter so as to extend into the activator and surround the medicament delivery member shield <NUM>. The medicament delivery member shield remover <NUM> is arranged with grip elements <NUM> that are inwardly inclined, proximally directed tongues that are capable of gripping into the surface of the medicament delivery member shield when the protective cap is pulled in the proximal direction in relation to the medicament delivery device.

The device is intended to function as follows. When the medicament delivery device is delivered to a user, a medicament container <NUM> with an attached medicament delivery member shield <NUM> has been placed in the medicament container holder <NUM> and a protective cap has been attached to the proximal end of the medicament delivery device. The drive spring <NUM> has been tensioned in that the plunger rod <NUM> has been pushed distally relative the actuator <NUM> such that the inwardly directed protrusions <NUM> of the holding members <NUM> of the actuator <NUM> engage with the recesses <NUM> of the plunger rod <NUM>, thereby holding the plunger rod <NUM>.

The rotator <NUM> is then pushed axially onto the actuator <NUM> from the proximal end. In order have the right rotational orientation of the rotator in relation to the actuator <NUM>, the rotator <NUM> is held such that the orientating elements, i.e. the protrusions <NUM>, will fit in the longitudinal grooves <NUM> of the rotator <NUM>. The rotator <NUM> is then pushed axially until the protrusions <NUM> fit into the cut-outs <NUM>, which prevents pulling back of the rotator <NUM>. In this rotational position, named first position, the distally directed end of the rotator <NUM> is in contact with the ledges <NUM> of the actuator <NUM> as seen in <FIG>. The holding members <NUM> of the actuator <NUM> are now prevented from moving out of engagement by the support surfaces <NUM> of the rotator <NUM> in contact with the outwardly directed protrusions <NUM> of the holding members <NUM>.

When a dose of medicament is to be delivered, the protective cap <NUM> is removed from the proximal end of the medicament delivery device by pulling it in the proximal direction. Because of the engagement of the tongues <NUM> with the medicament delivery member shield <NUM>, the medicament delivery member shield <NUM> will also be pulled in the proximal direction, removed from the medicament delivery member <NUM>. The proximal end of the medicament delivery device is then pressed against a dose delivery site. This causes the activator <NUM> to move inside and relative the housing <NUM>. This in turn causes the protrusions <NUM> of the activator <NUM> to move along the guide ridges <NUM> of the rotator <NUM> such that the protrusions will come in contact with the first guide ridge <NUM>i, which will cause the rotator <NUM> to turn around the longitudinal axis L of the device i.e. to rotate.

The turning/rotation of the rotator <NUM> will cause its distally directed end surface to slide along the ledges <NUM> as seen in <FIG> until the protrusions <NUM> have reached the second guide ridge <NUM>r. At the same time, in this second position, the cut-outs <NUM> of the rotator <NUM> have reached the ledges <NUM>, <FIG>, so that further pushing of the activator <NUM> will cause the rotator <NUM> to move axially i.e. to be linearly displaced in the distal direction with its support surfaces sliding in relation to the outwardly directed protrusions of the arms of the actuator. The axial movement of the rotator <NUM> is stopped when its distally directed end surface abuts the proximally directed stop surface <NUM> of the actuator. At this third position, the outwardly directed protrusions <NUM> of the holding members <NUM> of the actuator <NUM> have passed a proximal end surface of the rotator <NUM>, <FIG>, and have thus moved out of contact with inner surfaces of the rotator <NUM>. The holding members <NUM> of the actuator <NUM> are now free to flex outwardly, whereby the inwardly directed protrusions <NUM> of the holding members <NUM> are moved out of contact with the recesses <NUM> of the plunger rod <NUM>.

The flexing of the holding members <NUM> is rapid and outer surfaces of the holding members <NUM> will hit the rotator <NUM>, causing an audible and tactile signal that the dose delivery sequence has started. The plunger rod <NUM> is now free to move in the proximal direction due to the force of the drive spring <NUM>, wherein the proximal end of the plunger rod <NUM> acts on, and moves, the stopper <NUM> inside the medicament container <NUM> in the proximal direction such that a dose of medicament is expelled through the medicament delivery member <NUM>.

When the stopper <NUM> has been moved by the plunger rod <NUM> to almost the proximal end inside the medicament container <NUM>, the plunger rod <NUM> is moved out of contact with the arms <NUM> of the signalling element <NUM>. The arms <NUM> of the signalling element <NUM> are thus free to flex inwards such that the ledges <NUM> are moved out of contact with the surfaces <NUM> of the actuator <NUM>, and due to the force of the drive spring <NUM> in contact with and acting on the base <NUM> of the signalling element <NUM>, the signalling element <NUM> will be moved suddenly in the distal direction the distance D until the distal end of the signalling element <NUM> hits a proximally directed end wall of the actuator, thus providing an audible and tactile signal that the dose delivery sequence is completed and that it is safe to remove the medicament delivery device. It may now be discarded in a safe manner.

Claim 1:
A medicament delivery device comprising:
a generally tubular elongated housing (<NUM>) having a distal end (<NUM>) and a proximal end (<NUM>), the proximal end (<NUM>) being arranged with a central passage (<NUM>);
a plunger rod (<NUM>),
- a drive spring (<NUM>) operably arranged to the plunger rod,
- an actuator (<NUM>) comprising a holding member (<NUM>) releasably engaged to the plunger rod (<NUM>) for holding said plunger rod (<NUM>) with said drive spring (<NUM>) in a tensioned state,
- a rotator (<NUM>) having a generally tubular shape, the rotator (<NUM>) being operably connected and movable relative to said actuator (<NUM>) and configured to interact with said holding member (<NUM>) for holding said holding member (<NUM>) in engagement with the plunger rod (<NUM>),
- an activator (<NUM>) extending through the central passage (<NUM>) of the proximal end of the housing (<NUM>) and operably connected to said rotator (<NUM>), characterized by the activator (<NUM>) being configured to rotate and subsequently linearly displace the rotator (<NUM>) in relation to the actuator (<NUM>) such that said holding member (<NUM>) is released from the plunger rod (<NUM>) so that the plunger rod (<NUM>) is free to move in the proximal direction due to the force of the drive spring (<NUM>) so that a dose of medicament is expelled,
wherein said actuator (<NUM>) is arranged with a guide surface (<NUM>) on which said rotator (<NUM>) rests when rotated from a first position to a second position,
wherein said rotator (<NUM>) is arranged with a cut-out (<NUM>), in which said guide surface (<NUM>) can enter in the second position for allowing the subsequently linear displacement of the rotator (<NUM>) in relation to the actuator (<NUM>),
wherein the activator (<NUM>) comprises a proximal tubular part (<NUM>) and two distally directed arms (<NUM>) extending from the tubular part (<NUM>), with inwardly directed protrusions (<NUM>) arranged at the distal end of the arms (<NUM>),
wherein said rotator (<NUM>) comprises first guide ridges (<NUM>i) that cooperate with the protrusions (<NUM>) of the activator (<NUM>), which first guide ridges (<NUM>i) are inclined in relation to a longitudinal direction, and on which first guide ridges (<NUM>i) said activator (<NUM>) acts for rotating said rotator (<NUM>) from the first position to the second position,
wherein said activator (<NUM>) is a medicament delivery member guard.