Patent Description:
Medicament delivery devices such as auto-injectors nowadays provide possibilities for the users themselves to handle medicament delivery in an easy, safe and reliable manner.

Before a user commences a drug administration programme by means of an auto-injector, it may be valuable for the user to undergo training to learn how to administer a drug properly by means of a specific auto-injector. A training device may be used for this purpose. It is known to provide a feedback mechanism for indicating to the user when the appropriate volume of medicament has been injected by the auto-injector. There are feedback mechanism that indicate the user when the injector can be removed from an injection site.

<CIT> discloses a feedback mechanism for an injection device configured to deliver a medicament to a user. The feedback mechanism comprises a piston and a fluid chamber. The piston is adapted to move into the fluid chamber during use of the injection device. The feedback mechanism also has a damper arranged to damp movement of the piston. An indicator is arranged to provide feedback to the user after the piston has moved a pre-determined distance into the fluid chamber.

To conduct an exact imitation of the auto-injector functions, it is desired that the trainer is also able to produce signals for indicating the different steps in the injecting process for the user as the real auto-injectors. This will improve a training efficiency. Such feedback mechanisms can be different, produce different audio, tactical and visual signals and indicate a beginning or an end of the imitated injection process.

Furthermore, it is advantageous if the trainer device could be used a number of times for a training purpose. Therefore, it requires a possibility to be reset after a training operation for a multiple usage. Exemplary automatic injection training devices are known from <CIT> and <CIT>.

An object of the present disclosure is to provide a drive mechanism for a medicament delivery training device which solves or at least mitigates problems of the prior art.

There is hence according to a first aspect of the present disclosure provided a drive mechanism for a medicament delivery training device, the delivery mechanism comprising: a plunger rod having a proximal end and a distal end, a stopper provided on the proximal end of the plunger rod, and a container having an inner chamber, a proximal container end, and an open distal container end leading into the inner chamber, wherein the inner chamber has a distal portion and a proximal portion, wherein in an initial state of the delivery mechanism the plunger rod is axially fixedly arranged in a first position in which the stopper is arranged distally relative to the proximal portion, the plunger rod being biased towards the proximal container end, and wherein the plunger rod is configured to be released from the first position, causing the plunger rod to move towards the proximal container end and the stopper to impact with a stopper contact surface, resulting in an initial signal, and to subsequently move into the proximal portion.

A medicament delivery training device, for which the drive mechanism is designed for, may thereby simulate medicament administration of a real medicament delivery device. In particular, a user is due to the initial signal able to learn and understand when the medicament administration process is commenced during medicament administration.

The initial signal may be an initial sound such as an initial click.

According to one embodiment the stopper has an outer stopper diameter, the distal portion has a distal portion inner diameter and the proximal portion has a proximal portion inner diameter which is smaller than the distal portion inner diameter and the outer stopper diameter, the distal portion transitioning to the proximal portion via the stopper contact surface. The stopper hence impacts with the stopper contact surface because the outer stopper diameter is larger than the proximal portion inner diameter.

One embodiment comprises a holding structure provided with a radially flexible arm, wherein the plunger rod is provided with a radial recess configured to engage with the radially flexible arm to maintain the plunger rod axially fixed in the distal portion.

One embodiment comprises an actuator sleeve configured to receive the holding structure, the actuator sleeve being configured to move between a proximal position and a distal position, wherein in the proximal position the actuator sleeve is configured to urge the radially flexible arm radially inwards to engage with the radial recess.

According to one embodiment when the actuator sleeve is in the distal position the actuator sleeve is configured to enable the radially flexible arm to move radially outwards to disengage from the radial recess, thereby releasing the plunger rod from the first position.

According to one embodiment the actuator sleeve is biased towards the proximal position.

One embodiment comprises a delivery member cover configured to move linearly relative to the container, between an initial position and an activating position, wherein the delivery member cover is configured to move the actuator sleeve from the proximal position to the distal position when moved from the initial position to the activating position.

One embodiment comprises a housing configured to receive the container, wherein the housing has an inner stop structure configured to stop proximal movement of the plunger rod in the inner chamber, causing the stopper to impact with the stop structure, resulting in a subsequent signal.

The subsequent signal may be a subsequent audible sound such as a click.

A user may thereby be able to learn and understand when a medicament administration process has been finalised.

According to one embodiment the stop structure comprises a plurality of radially inwards extending protrusions.

According to one embodiment the container is provided with a proximal engagement structure configured to engage with the housing.

According to one embodiment the radially inwards extending protrusions and the proximal engagement structure are arranged to form a central proximal opening into the container.

According to one embodiment the stopper is made of a resilient material.

According to one embodiment the proximal portion inner diameter is dimensioned to cause friction between the stopper and the inner surface of the proximal portion to control a driving speed of the plunger rod.

There is according to a second aspect of the present disclosure provided a medicament delivery training device comprising a delivery mechanism according to the first aspect.

According to one embodiment the drive mechanism is configured to be actuated mechanically or electrically.

All references to "a/an/the element, apparatus, component, means, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, etc.", unless explicitly stated otherwise.

In the present disclosure, when the term "distal" is used, this refers to the direction pointing away from the dose delivery site. When the term "distal part/end" is used, this refers to the part/end of the medicament delivery training device, or the parts/ends of the members thereof, which under use of the medicament delivery training device is/are located furthest away from the dose delivery site. Correspondingly, when the term "proximal" is used, this refers to the direction pointing to the dose delivery site. When the term "proximal part/end" is used, this refers to the part/end of the medicament delivery training device, or the parts/ends of the members thereof, which under use of the medicament delivery training device is/are located closest to the dose delivery site.

Further, the term "longitudinal", with or without "axis", refers to a direction or an axis through the device or components thereof in the direction of the longest extension of the device and/or component.

Similarly, the terms "radial", "transversal" or "orthogonal" refers to a direction generally perpendicular to the longitudinal direction which is the axis direction and e.g. "radially or orthogonally outward" will refer to a direction pointing away for the longitudinal axis.

<FIG> depicts an example of a medicament delivery training device <NUM>. The medicament delivery training device <NUM> is a dummy device to be used for learning how a corresponding real medicament delivery device is to be handled and operated.

The medicament delivery training device <NUM> has a proximal end 1a and a distal end 1b. The medicament delivery training device <NUM> comprises a housing <NUM> and a cap <NUM>. The cap <NUM> is configured to be removably attached to the housing <NUM>. The cap <NUM> forms the proximal end 1a of the medicament delivery training device <NUM> when attached to the housing <NUM>.

<FIG> shows an exploded view of the medicament delivery training device <NUM>. The exemplified medicament delivery training device <NUM> comprises a resetting structure 5a. The resetting structure 5a has an elongated shape. The resetting structure 5a may comprise a rod. The resetting structure 5a is configured to be attached to the cap <NUM>. The cap <NUM> has a distal opening 5b configured to receive the resetting structure 5a. The resetting structure 5a extends in the distal direction from the cap <NUM> when fitted in the cap <NUM>, along a central axis of the cap <NUM>.

The medicament delivery training device <NUM> comprises a delivery member cover <NUM>, and a first resilient member <NUM> configured to bias the delivery member cover <NUM> in the proximal direction. The exemplified first resilient member <NUM> may be a spring. The delivery member cover <NUM> is configured to be received by the housing <NUM>. The delivery member cover <NUM> is configured to be moved linearly relative to the housing <NUM>, between an initial position and an activation position. The delivery member cover <NUM> extends more in the proximal direction from the housing <NUM> in the initial position than in the activation position. Hereto, the initial position is an extended position and the activation position is a retracted position relative to the housing <NUM>. The first resilient member <NUM> is configured to bias the delivery member cover <NUM> towards the initial position, i.e. the extended position.

The medicament delivery training device <NUM> comprises a container <NUM>. The container <NUM> is a syringe dummy. Since it is the syringe dummy, the exemplified container <NUM> does not comprise any needle or canula. The container <NUM> has an inner chamber 11a. The inner chamber 11a extends through the container <NUM>. The container <NUM> has an open distal container end 11b. The container <NUM> has an open proximal container end 11c. The inner chamber 11a extends between the open distal container end 11b and the open proximal container end 11c.

The medicament delivery training device <NUM> comprises a plunger rod <NUM>. The plunger rod <NUM> is provided with a stopper <NUM>. The stopper <NUM> is provided on a proximal end of the plunger rod <NUM>. The stopper <NUM> may be made of an elastic, resilient or flexible material.

The plunger rod <NUM> may have a proximal end face or cap/cover which may form part of the stopper <NUM> or which may extend in the proximal direction from the stopper <NUM>. The proximal end face of the plunger rod <NUM> may be made of a rigid material such as a plastic material or a metal. In examples in which the plunger rod has a proximal end face, the proximal end face and the elastic stopper body together form the stopper as defined herein.

The plunger rod <NUM>, the stopper <NUM> and the container <NUM> forms part of a drive mechanism of the medicament delivery training device <NUM>.

The container <NUM> is configured to receive the plunger rod <NUM>. The plunger rod <NUM> is configured to extend in the proximal direction into the inner chamber 11a through the open distal container end 11b.

The exemplified plunger rod <NUM> comprises a recess 13a. The recess 13a is a radial recess. In the example shown in <FIG>, the recess 13a extends a full turn in the circumferential direction. The plunger rod <NUM> could alternatively comprise a plurality of physically separate recesses distributed in the circumferential direction. The recess 13a may have an inclined distal transition surface, relative to the central axis of the plunger rod <NUM>, where the recess 13a transitions to the outer surface of the plunger rod <NUM>.

The medicament delivery training device <NUM> comprises a second resilient member <NUM> configured to bias the plunger rod <NUM> in the proximal direction. The second resilient member <NUM> may be a spring. The second resilient member <NUM> is configured to be received by the plunger rod <NUM>. The plunger rod <NUM> may hence be hollow.

The medicament delivery training device <NUM> comprises a holding structure <NUM>. The holding structure <NUM> is configured to be received by the housing <NUM>. The holding structure <NUM> is configured to be fixedly arranged in the housing <NUM>. The holding structure <NUM> is axially fixed relative to the housing <NUM>. The holding structure <NUM> is arranged in a distal portion of the housing <NUM>. The holding structure <NUM> is an elongated structure. The holding structure <NUM> is hollow. The holding structure <NUM> is configured to receive a distal end portion 13b of the plunger rod <NUM>.

The holding structure <NUM> comprises a plurality of radially flexible arms 21a. The radially flexible arms 21a extend in the proximal direction. The radially flexible arms 21a form a proximal end of the holding structure <NUM>. Each radially flexible arm 21a is configured to engage with the recess 13a of the plunger rod <NUM>. Each radially flexible arm 21a comprises a radially inwards extending protrusion configured to engage with the recess 13a.

The medicament delivery training device <NUM> comprises an actuator sleeve <NUM>. The actuator sleeve <NUM> is configured to be arranged around a proximal portion of the holding structure <NUM>. The actuator sleeve <NUM> is configured to be moved linearly relative to the holding structure <NUM> between a proximal position and a distal position. The delivery member cover <NUM> is configured to move the actuator sleeve <NUM> from the proximal position to the distal position. When the delivery member cover <NUM> is in the initial position, the actuator sleeve <NUM> is arranged in the proximal position. When the delivery member cover <NUM> is moved in the distal direction towards the activation position, the actuation sleeve <NUM> is moved towards the distal position. The actuator sleeve <NUM> has a proximal flange 19a. The delivery member cover <NUM> has distally extending legs configured to bear against/engage with the proximal flange 19a when the delivery member cover <NUM> is moved towards the activation position. The actuation sleeve <NUM> is thereby moved towards the distal position as the delivery member cover <NUM> is moved in the distal direction.

The actuator sleeve <NUM> is configured to be arranged around the radially flexible arms 21a and urge the radially flexible arms 21a to engage with the recess 13a of the plunger rod <NUM> when the actuator sleeve <NUM> is in the proximal position.

The medicament delivery training device <NUM> comprises a third resilient member <NUM>. The third resilient member <NUM> may be a spring. The third resilient member <NUM> is configured to bias the actuator sleeve <NUM> in the proximal direction towards the proximal position. The holding member <NUM> has a distal flange surface 21b. The third resilient member <NUM> is configured to be arranged between the distal end of the proximal flange 19a of the actuator sleeve <NUM> and the distal flange surface 21b. The third resilient member <NUM> thereby biases the actuator sleeve <NUM> in the proximal direction towards the proximal position.

<FIG> shows a perspective view of the housing <NUM>. The housing <NUM> has an inner stop structure 3a. The stop structure 3a comprises a plurality of radially inwards extending protrusions 3b. The radially inwards extending protrusions 3b form a central proximal opening 3c between them. The radially inwards extending protrusions 3b do hence not meet as they extend towards the central axis of the housing <NUM>. The central proximal opening 3c is dimensioned such that the resetting structure 5a may be received through the central proximal opening 3c when the cap <NUM> with the resetting structure 5a is attached to the housing <NUM> and hence the resetting structure 5a is inserted into the housing <NUM>. The central proximal opening 3c is dimensioned such that the stopper <NUM> is not able to move through the central proximal opening 3c when the plunger rod <NUM> is moved in the proximal direction, as will be explained in what follows. Hereto, the stopper <NUM> has an outer stopper diameter which is larger than the central proximal opening 3c.

<FIG> shows a perspective view of the housing <NUM> when the container <NUM> is arranged in the housing <NUM>. The container <NUM> is provided with a proximal engagement structure 11d configured to engage with the housing <NUM>. The proximal engagement structure 11d comprises a plurality of radially outwards extending flexible snap structures 11e. According to the present example, the housing <NUM> has a radially inwards extending structure 3d between each adjacent pair of radially inwards extending protrusion 3b. The radially inwards extending structures 3d have a shorter radially inwards extension than the radially inwards extending protrusions 3b. Each of the plurality of radially outwards extending flexible snap structures 11e is configured to engage with a respective radially inwards extending structure 3d. The container <NUM> is thereby attached to the housing <NUM>.

<FIG> shows a longitudinal sectional view of the container <NUM>. The container <NUM> has a proximal container end 11f and a distal container end <NUM>. The inner chamber or channel 11a which extends between the proximal container end 11f and the distal container end <NUM> has a proximal portion <NUM> and a distal portion 11i. The proximal portion has a proximal portion inner diameter d1 and the distal portion 11i has a distal portion inner diameter d2. The proximal portion inner diameter d1 is smaller than the distal portion inner diameter d2.

The open distal container end 11b opens into the distal portion 11i. The distal portion 11i transitions to the proximal portion <NUM> via a stopper contact surface 11j. The stopper contact surface 11j may for example be inclined relative to the central longitudinal axis of the container <NUM>, as shown in <FIG>, or it may be orthogonal to the central longitudinal axis. In the former case, the stopper contact surface 11j provides a gradual decrease of the inner diameter of the container <NUM> in the proximal direction. In the latter case, the stopper contact surface forms a step between the distal portion 11i and the proximal portion <NUM>.

The outer stopper diameter may for example be defined by the largest outer dimension or diameter of the stopper <NUM>. The proximal portion inner diameter d1 is smaller than the outer stopper diameter. The proximal portion inner diameter d1 is dimensioned to provide friction onto the stopper <NUM> to control the driving speed of the plunger rod <NUM>. The driving speed should preferably simulate the driving speed of the plunger rod of the corresponding real medicament delivery device which the medicament delivery training device <NUM> is designed to simulate.

<FIG> shows a perspective view of the plunger rod <NUM>, the actuator sleeve <NUM> and the holding structure <NUM>.

<FIG> is a perspective view of the cap <NUM> with the resetting structure 5a attached to the cap <NUM>. In a typical example, the resetting structure 5a is fixedly attached to the cap <NUM> such that when the cap <NUM> is removed from the housing <NUM>, the resetting structure 5a is also removed from the housing <NUM> together with the cap <NUM>.

<FIG> shows a longitudinal section of the medicament delivery training device <NUM> in an initial state thereof. The initial state is the state of the medicament delivery training device <NUM> before it has been activated. In the initial state, the cap <NUM> is attached to the housing <NUM>. The resetting structure 5a extends into the container <NUM> through the central proximal opening 3c of the housing <NUM>. The drive mechanism is also in an initial state when the medicament delivery training device <NUM> is in the initial state.

The actuator sleeve <NUM> is arranged in the proximal position as it is biased by the third resilient member <NUM> in the proximal direction and the delivery member cover <NUM> is in the initial position in which it does not apply any, or at least negligible force in the distal direction onto the actuator sleeve <NUM>. The radially flexible arms 21a are hence urged radially inwards by the actuator sleeve <NUM> which is arranged around the radially flexible arms 21a. The radially flexible arms 21a thereby engage with the recess 13a. The plunger rod <NUM> is therefore maintained in a first position in which it extends through the open distal container end 11b and the stopper <NUM> is arranged fixed in the distal portion 11i of the container <NUM>. The proximal end of the stopper <NUM> is typically arranged at a distance from the stopper contact surface 11j.

When a user is to perform training with the medicament delivery training device <NUM>, the cap <NUM> is first to be removed from the housing <NUM>. This is shown in <FIG>. As the cap <NUM> is removed, so is the resetting structure 5a. The delivery member cover <NUM> is in the initial position, i.e. in the extended position relative to the housing <NUM>. The plunger rod <NUM> is still fixed in the first position as in the initial state depicted in <FIG>.

In <FIG>, the delivery member cover <NUM> has been moved into the housing <NUM> to the activation position as shown by arrow A. This may for example be achieved by a user pressing the medicament delivery training device <NUM> towards an intended site of injection. The delivery member cover <NUM> has pushed the actuation sleeve <NUM> in the distal direction towards the distal position, as shown by arrow B. The actuation sleeve <NUM> is hence moved distally from the radially flexible arms 21a. Since the plunger rod <NUM> is biased in the proximal direction and urged towards the proximal container end 11c, the radially flexible arms 21a are now moved out from the recess 13a. The plunger rod <NUM> is hence released and moved in the proximal direction further into the container <NUM>.

<FIG> shows the medicament delivery training device <NUM> when the plunger rod <NUM> has been released from its engagement with the holding structure <NUM>. The stopper <NUM> has moved from the distal portion 11i into the proximal portion <NUM> of the inner chamber 11a via the stopper contact surface 11j, as shown by arrow C. As the stopper <NUM> is moved from the distal portion 11i into the proximal portion <NUM>, the stopper impacts with the stopper contact surface 11j, since the outer stopper diameter is larger than the proximal portion inner diameter d1. This impact results in an initial signal. The initial signal may be an audible sound such as a click. A user will thereby become aware that simulated medicament administration has commenced.

In <FIG> the plunger rod <NUM> has been further moved in the proximal direction inside the container <NUM> as shown by arrow D.

In <FIG>, the stopper <NUM> has impacted with the housing <NUM>, in particular with the inner stop structure 3a with the plurality of radially inwards extending protrusions 3b. A subsequent signal is generated by this impact. The subsequent signal may for example be an audible sound such as a click. A user of the medicament delivery training device <NUM> will thereby understand that the simulated medicament injection has been finalised.

In <FIG> the medicament delivery training device <NUM> has been removed from the injection site by the user. The delivery member cover <NUM> is hence moved back to the initial position due to its proximal biasing, as shown by arrow E. As a result, the actuation sleeve <NUM> is moved back to the proximal position from the distal position.

In this used state of the medicament delivery training device <NUM>, the medicament delivery training device <NUM> may be reset manually for further training. The plunger rod <NUM> may in particular be reset to the first position.

This resetting may be performed by manually inserting the resetting structure 5a. In particular, the resetting may be performed manually by a user placing the cap <NUM> back onto the housing <NUM>.

<FIG> shows a resetting operation of the medicament delivery training device <NUM>. The cap <NUM> is being placed back onto the housing <NUM> as shown by arrow F. The resetting structure 5a thereby first penetrates the central proximal opening 3c formed between the radially inwards extending protrusions 3b and subsequently the open proximal container end 11c of the container <NUM>. The resetting structure 5a has a distal end tip 5c which pushes the plunger rod <NUM> in the distal direction towards the first position, as shown by arrow G. The resetting structure 5a has a length which enables it to reset the plunger rod <NUM> in the first position when the cap <NUM> is attached to the housing <NUM>. Hence, as the resetting structure 5a is moved further into the container <NUM> the recess 13a of the plunger rod <NUM> will become aligned with the radially flexible arms 21a, which at this time are urged radially inwards by the actuator sleeve <NUM> arranged in the proximal position and hence around the radially flexible arms 21a. The radially flexible arms 21a will therefore engage with the recess 13a and the plunger rod <NUM> once again becomes fixedly arranged in the first position with the stopper <NUM> arranged in the distal portion 11i of the container <NUM>. This is shown in <FIG>, where the medicament delivery training device <NUM> has once again obtained its initial state in which it is ready to be used for further training.

Claim 1:
A drive mechanism for a medicament delivery training device (<NUM>), the delivery mechanism comprising:
a plunger rod (<NUM>) having a proximal end and a distal end, wherein the proximal end is pointing towards a delivery site,
a stopper (<NUM>) provided on the proximal end of the plunger rod (<NUM>), and
a container (<NUM>) having an inner chamber (11a), a proximal container end (11c), and an open distal container end (11b) leading into the inner chamber (11a), wherein the inner chamber (11a) has a distal portion (11i) and a proximal portion (<NUM>),
wherein the stopper (<NUM>) has an outer stopper diameter, the distal portion (11i) has a distal portion inner diameter (d2) and the proximal portion (<NUM>) has a proximal portion inner diameter (d1) which is smaller than the distal portion inner diameter (d2) and the outer stopper diameter, the distal portion (11i) transitioning to the proximal portion (<NUM>) via a stopper contact surface (11j), wherein the drive mechanism is configured such that
in an initial state of the delivery mechanism the plunger rod (<NUM>) is axially fixedly arranged in a first position in which the stopper (<NUM>) is arranged distally relative to the proximal portion (<NUM>), and the plunger rod (<NUM>) is biased towards the proximal container end (11c), and wherein the plunger rod (<NUM>) is configured to be released from the first position, causing the plunger rod (<NUM>) to move towards the proximal container end (11c) and the stopper (<NUM>) to impact with the stopper contact surface (11j), and to subsequently move into the proximal portion (<NUM>), characterised in that the stopper (<NUM>) and the stopper contact surface (11j) are configured such that said impact results in an initial signal.