WO2026012757A1

WO2026012757A1 - Medicament delivery device

Info

Publication number: WO2026012757A1
Application number: PCT/EP2025/068010
Authority: WO
Inventors: Hizballah ARHAM
Original assignee: SHL Medical AG
Current assignee: SHL Medical AG
Priority date: 2024-07-11
Filing date: 2025-06-26
Publication date: 2026-01-15
Anticipated expiration: 2027-01-11

Abstract

Medicament Delivery Device A medicament delivery device (100) comprises a drive assembly (102) and a removeable cassette (104) The drive assembly (102) has a plunger rod (200) with tabs (406). A rotator (204) is arranged to transfer force from the drive member (202) to the plunger rod (200) via the tabs (406). The rotator (204) has a first rotational orientation, a second rotational orientation and axial positions, in which axial positions it is prevented from movement in the proximal direction when in the first rotational orientation and released for the movement in the proximal direction when in the second rotational orientation. An actuator (206) causes the rotator (204) to rotate from the first rotational orientation to the second rotational orientation when in the axial positions and a resetting arrangement causes the rotator (204) to rotate from the second rotational orientation to the first rotational orientation as the rotator (204) moves in the proximal direction between the axial positions. The rotator (204) is arranged to transfer the force from the drive member (202) to the plunger rod (200) by having a proximally facing surface (608) that cooperates with the tabs (406) and has a gap (610) in the proximally facing surface (608) that allows the plunger rod (200) to move in the distal direction by the tabs (406) passing through the gap (610) when the rotator (204) is in first rotational orientation.

Description

Medicament Delivery Device

Field of the Disclosure

The present disclosure relates to a medicament delivery device, and particularly but not exclusively to a drive assembly of the medicament delivery device, a removable cassette, and an arrangement and method for securing the removable cassette to the drive assembly.

Background

A medicament delivery device may house a medicament container, typically a syringe, that contains a medicament for delivery to a user, e.g. by injection. A plunger rod biased by a drive member, typically a compression spring, may be arranged to transfer force provided by the drive member to a piston of the medicament container to expel the medicament from the medicament container. In one example, the medicament container may be housed in a cassette removably mountable to a drive assembly of the medicament delivery device. In this way, the drive assembly can be reused several times with different removable cassettes housing different medicament containers to deliver multiple doses of medicament.

Summary of the Disclosure

Aspects of the disclosure are defined in the accompanying claims.

According to one aspect of the disclosure, there is provided a drive assembly for a medicament delivery device, the drive assembly extending along a longitudinal axis between a proximal end that in use is located towards a site at which a medicament is delivered to a user by the medicament delivery device and a distal end, and the drive assembly comprising: a drive member; a plunger rod arranged for movement in a proximal direction to urge a piston of a medicament container to expel the medicament from the medicament container, the plunger rod having tabs that extend radially at two or more axial positions, which axial positions are spaced from one another along the length of the plunger rod; a rotator arranged to transfer force from the drive member to the plunger rod to cause the plunger rod to move in the proximal direction, the rotator having a first rotational orientation, a second rotational orientation and axial positions, in which axial positions it is prevented from movement in the proximal direction when in the first rotational orientation and released for the movement in the proximal direction when in the second rotational orientation; an actuator arranged for movement in a distal direction to cause the rotator to rotate from the first rotational orientation to the second rotational orientation when in the axial positions; and a resetting arrangement for causing the rotator to rotate from the second rotational orientation to the first rotational orientation as the rotator moves in the proximal direction between the axial positions, wherein the rotator is arranged to transfer the force from the drive member to the plunger rod by having a proximally facing surface that cooperates with at least one of the tabs of the plunger rod to urge the plunger rod for the movement in the proximal direction as the rotator moves in the proximal direction between the axial positions, and wherein the rotator has a gap in the proximally facing surface that allows the plunger rod to move in the distal direction by the tabs passing through the gap when the rotator is in first rotational orientation.

Optionally, the tabs comprise groups of tabs, the tabs of each respective group of tabs being located at the same axial position along the length of the plunger rod but at different locations around the circumference of the plunger rod.

Optionally, the tabs of each respective group of tabs are spaced equally around the circumference of the plunger rod.

Optionally, each group of tabs comprises two tabs (406) offset from one another by 180° around the circumference of the plunger rod.

Optionally, the rotator has a retainer with a distally facing surface (616) arranged to cooperate with the one or more of the tabs when the rotator is in the first rotational orientation to prevent the plunger rod from moving in the proximal direction.

Optionally, the distally facing surface of the retainer is provided by a protrusion extending radially inwards.

Optionally the drive assembly has a return mechanism comprising: a traveler biased to move in the distal direction; and a retaining element having a first position in which it prevents the traveler from moving in the distal direction and a second position in which it releases the traveler to move in the distal direction, wherein the plunger rod has a return protrusion that cooperates with the retaining element after the movement of the plunger rod in the proximal direction to cause the retaining element to move from the first position to the second position to release the traveler to move in the distal direction and a distally facing surface with which the traveler cooperates to urge the plunger rod in the distal direction as the traveler moves in the distal direction.

Optionally, the drive assembly comprises a biasing element, wherein the traveler is biased to move in the distal direction by being urged in the distal direction by the biasing element.

Optionally, the biasing element also biases the actuator (206) in the proximal direction.

Optionally, the biasing element is a compression spring.

Optionally, the traveler is generally ring-shaped.

Optionally, the retaining element comprises a proximally facing surface.

Optionally the drive assembly comprises a housing, wherein the proximally facing surface is provided by a protrusion extending radially inwards from the housing.

Optionally, the drive assembly comprises a retaining arrangement between the rotator and the housing, the retaining arrangement comprising a protrusion arranged to ride against a circumferentially extending surface to retain the rotator at one of the axial positions.

Optionally the protrusion of the retaining arrangement is provided on the rotator and the circumferentially extending surface is provided on the housing.

Optionally, the housing has at least one additional circumferentially extending surface, one of the circumferentially extending surface and the additional circumferentially extending surface(s) corresponding to each of the axial positions of the rotator respectively, and the protrusion being arranged to ride against a respective one of the circumferentially extending surface and the additional circumferentially extending surface(s) corresponding the axial position that the rotator is in whilst the medicament delivery device is a given configuration.

Optionally, the drive assembly comprises a resetting arrangement between the housing and the rotator, the resetting arrangement comprising a protrusion arranged to ride against a ramp such that movement of the rotator axially in the proximal direction between two of the axial positions forces the protrusion along the ramp such that the rotator rotates from the second rotational orientation to the first rotational orientation.

Optionally, the protrusion of the resetting arrangement is provided on the rotator and the ramp is provided on the housing.

Optionally, the protrusion of the retaining arrangement is the same element as the protrusion of the resetting arrangement.

Optionally, the resetting arrangement further comprises an additional ramp on the rotator against which a protrusion of the actuator rides to urge the rotator towards the first rotational orientation as the actuator moves axially in the proximal direction.

Optionally, the drive assembly comprises an actuating arrangement between the actuator and the rotator, the actuating arrangement comprising a protrusion riding against a ramp such that the movement of the actuator in the distal direction forces the protrusion along the ramp such that the rotator rotates from the first rotational orientation to the second rotational orientation to release the rotator and the plunger rod for the movement in the proximal direction.

According to another aspect of the disclosure, there is provided a medicament delivery device comprising the drive assembly described above.

Optionally, the medicament delivery device comprises a removeable cassette, the removeable cassette comprising: a medicament container carrier for accommodating a medicament container having a delivery member; and a delivery member cover having a first position in which it covers the delivery member and a second position in which it exposes the delivery member for delivery of a medicament from the medicament container, wherein the removeable cassette is releasably secured to the drive assembly by the delivery member cover engaging with the actuator.

According to another aspect of the disclosure, there is provided a medicament delivery device comprising a drive assembly and a removeable cassette, the drive assembly comprising: a drive member; a plunger rod arranged for movement in a proximal direction to urge a piston of a medicament container to expel a medicament from the medicament container; and an actuator moveable in a distal direction to cause the plunger rod to be released for the movement in the proximal direction, and the removeable cassette comprising: a medicament container carrier for accommodating the medicament container having a delivery member; and a delivery member cover having a first position in which it covers the delivery member and a second position in which it exposes the delivery member for delivery of a medicament from the medicament container, wherein the removeable cassette is releasably secured to the drive assembly by the delivery member cover engaging with the actuator.

Optionally, the removable cassette and the drive assembly have a first rotational orientation in which the delivery member cover cooperates with the actuator to secure the removeable cassette to the drive assembly and a second rotational orientation in which the delivery member cover and the actuator are separable from one another to release the removeable cassette from the drive assembly.

Optionally, the removeable cassette is releasably secured to the drive assembly by the delivery member cover engaging with a proximal end of the actuator.

Optionally, one of the delivery member cover and the actuator has a protrusion and the other of the delivery member cover and the actuator has a recess, the protrusion and the recess cooperating to secure the removeable cassette to the drive assembly. Optionally, the protrusion is provided on the delivery member cover and the recess is provided on the actuator.

Optionally, the protrusion is in the form of a circumferentially extending ridge and the recess is in the form of a circumferentially extending slot.

Brief Description of the Drawings

Embodiments of the disclosure are now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic perspective view of a medicament delivery device according to an embodiment of the disclosure, with a housing of a removeable cassette removed to aid understanding;

Fig. 2 is a schematic exploded perspective view of some of the components of the medicament delivery device shown in Fig. 1;

Fig. 3 is a schematic close up perspective view of an attachment mechanism of the medicament delivery device shown in Fig. 1 in an unconnected state;

Figs. 4A to 4D are schematic perspective views of a plunger rod of the medicament delivery device shown in Fig. 1, with Figs. 4C and 4D showing close up views of tabs of the plunger rod;

Fig. 5 is a schematic perspective view of a rear cap of the medicament delivery device shown in Fig. 1;

Fig. 6 is a schematic perspective view of a rotator of the medicament delivery device shown in Fig. 1;

Fig. 7 is a schematic perspective view of an actuator of the medicament delivery device shown in Fig. 1;

Figs. 8A to 8C are views of a housing of the medicament delivery device shown in Fig. 1, with Figs. 8A and 8B being perspective views and Fig. 8C being a longitudinal sectional view in the plane B-B shown in Fig. 8A;

Fig. 9 is a schematic perspective view of biasing element and traveler of the medicament delivery device shown in Fig. 1; Figs. 10A to IOC are schematic perspective views of a method of attaching the removable cassette to a drive assembly of the medicament delivery device shown in Fig. 1, in which some or all of a housing of the drive assembly is cut away to assist understanding;

Fig. 11 is a schematic perspective view the medicament delivery device shown in Fig. 1 in a first configuration, ready to deliver a medicament on a first occasion;

Figs. 12A to 12D are close up views of components of the medicament delivery device in the first configuration;

Fig. 13 is a schematic perspective view the medicament delivery device shown in Fig. 1 after being activated to deliver a medicament on the first occasion;

Figs. 14A to 14D are close up views of components of the medicament delivery device after being activated to deliver a medicament on the first occasion;

Fig. 15 is a schematic perspective view the medicament delivery device shown in Fig. 1 during delivery of the medicament on the first occasion;

Figs. 16A to 16C are close up views of components of the medicament delivery device during delivery of the medicament on the first occasion;

Fig. 17 is a schematic perspective view the medicament delivery device shown in Fig. 1 after delivery of the medicament on the first occasion;

Figs. 18A and 18B are close up views of components of the medicament delivery device after delivery of the medicament on the first occasion;

Fig. 19 is a schematic perspective view the medicament delivery device shown in Fig. 1 during removal of the removable cassette after delivery of the medicament on the first occasion;

Fig. 20 is a schematic perspective view the medicament delivery device shown in Fig. 1 in a second configuration, ready to deliver a medicament on a second occasion;

Fig. 21 is a schematic perspective view the medicament delivery device shown in Fig. 1 in a third configuration, ready to deliver a medicament on a third occasion.

Detailed Description of the Preferred Embodiments In the present disclosure, when the terms "distal direction" or "distally" are used, they refer to a direction pointing away from a medicament delivery site during use of the medicament delivery device. When the term "distal" is used, it refers to a location away from the medicament delivery site in use. For example, a "distal" part or end of the medicament delivery device, or a "distal" part or end of a component of the medicament delivery device, is a part or end that is located furthest away from the medicament delivery site in use. Correspondingly, when the terms "proximal direction" or "proximally" are used, they refer to a direction pointing towards the medicament delivery site during use of the medicament delivery device. When the term "proximal" is used it refers to a location closest to the medicament delivery site in use. For example, a "proximal" part or end of the medicament delivery device, or a "proximal" part or end of a component of the medicament delivery device, is a part or end that is located closest to the medicament delivery site in use.

The terms "longitudinal", "axial", "longitudinally" and "axially" refer to a direction extending from a proximal end to a distal end, typically along the device or a component thereof in the direction of the longest extension of the device and/or component.

The terms "transverse", "transversal" and "transversally" refer to a direction generally perpendicular to the longitudinal direction.

The terms "circumference", "circumferential", or "circumferentially" refer to a circumference or a circumferential direction relative to an axis, typically a central axis extending in the direction of the longest extension of the device and/or component. The terms "radial" or "radially" refer to a direction extending radially relative to the axis, and "rotation", "rotational" and "rotationally" refer to rotation relative to the axis.

Referring to Fig. 1, a medicament delivery device 100 comprises a drive assembly 102 to which a removable cassette 104 may be mounted. Multiple removable cassettes 104 are usable with the same drive assembly 102. That is, the drive assembly 102 is reusable. In the embodiment described below, the drive assembly 102 may be used three times, with three removeable cassettes 104. However, other variations are possible, with the principles of operation of the drive assembly 102 being applicable for embodiments involving 2 or more reuses, e.g. between 2 and 10 times, although the medicament delivery device 100 will generally be longer when arranged for more reuse.

In more detail, the drive assembly 102 of the illustrated embodiment comprises a body 106 that is generally tubular and extends between a distal end 108 and a proximal end 110 along a longitudinal axis A. A rear cap 112 is mounted at the distal end 108 of the body 106. A flexible arm 114 is provided in a side wall of the body 106, as described in more detail below. Indeed, in the illustrated embodiment, the body 106 has two flexible arms 114, although only one is visible in Fig. 1. The flexible arms 114 are located radially opposite one another, that is offset by 180 degrees around the circumference of the body 106.

The removable cassette 104 also has a body (not shown) housing a medicament container carrier 116 and a delivery member cover 118. The medicament container carrier 116 carries a medicament container 120, which in the illustrated embodiment is a syringe. Arms 124 of the medicament container carrier 116 are visible in Fig. 1, which arms 124 cooperate with the housing 106 of the drive assembly 106 to limit the extent to which the removable cassette 104 is insertable into the drive assembly 102, as described in more detail below. There is also a cap 122 removably mountable to a proximal end of the removeable cassette 104.

The medicament delivery device 100 is shown in more detail in the exploded view of Fig. 2. This shows that the drive assembly 102 further comprises a plunger rod 200, drive member 202, rotator 204, actuator 206, biasing element 208 and traveler 210. It also shows the medicament container carrier 116, delivery member cover 118 and medicament container 120 of the removeable cassette 104 more clearly, and that the cap 122 of the removable cassette 104 carries a delivery member shield remover 216 for removing a delivery member shield 218 of the medicament container 120. Moreover, it can be seen that the medicament container 120 has a piston 220, which piston 220 may be moved along the length of the medicament container 120 to expel a medicament from the medicament container 120.

Referring to Fig. 3, the medicament delivery device 100 has an attachment mechanism for releasably securing the removeable cassette 104 to the drive assembly 102. The removeable cassette 104 is mountable to the drive assembly 102 by the delivery member cover 118 engaging with the actuator 206. Typically, one of the delivery member cover 118 and the actuator 206 has a protrusion 300 and the other of the delivery member cover 118 and the actuator 206 has a recess 302, and the protrusion 300 and the recess 302 cooperate with one another to releasably secure the removeable cassette 104 to the drive assembly 206.

In the illustrated embodiment, the protrusion 300 is provided on the delivery member cover 118 and the recess 302 is provided on the actuator 206. The protrusion 300 is in the form of a ridge or flange and the recess 302 is in the form of a groove or slot. Two ridges and two slots are provided in the illustrated embodiment. The ridges and the slots each extend circumferentially. The ridges are provided on a side wall of the delivery member cover 118, protruding in a radially outward direction. The slots are provided on a proximally facing end surface of the actuator 206. The ridges are offset from one another by 180 degrees around the circumference of the delivery member cover 118 and the slots are offset from one another by 180 degrees around the circumference of the actuator 206.

Each of the slots is open at one end 304, which end 304 faces in the same direction circumferentially for each slot. When the removable cassette 104 is mounted to the drive assembly 102, the ridges and slots align axially such that rotating the removable cassette 104 relative to the drive assembly 102 causes the ridges to enter the slots through open ends 304 of the slots. With the ridges in the slots, relative axial movement between the delivery member cover 118 and the actuator 206 is prevented and the removable cassette 104 is secured to the drive assembly 102. Reversing the rotation causes the ridges to come out of the slots such that relative axial movement between the delivery member cover 118 and the actuator 206 becomes possible again and the removable cassette 104 is released from the drive assembly 102. This might generally be understood to be a bayonet type fitting. Other similar arrangements for securing the delivery member cover 118 to the actuator 206, and hence the removeable cassette 104 to the drive assembly 102, are possible, such as a snap fit or threaded arrangement, meaning that the protrusion 300 and recess 302 may take other forms in other embodiments.

Referring to Figs. 4A to 4D, the plunger rod 200 is elongate and extends from a proximal end 400 to a distal end 402. When the plunger rod 200 is mounted in the medicament delivery device 100, the length of the plunger rod 200 is aligned with the main axis A of the drive assembly 102. The proximal end 400 is arranged to engage with the piston 220 of the medicament container 120 and the distal end 402 is arranged to engage with the rear cap 112, which is illustrated in more detail in Fig. 5.

Referring to Figs. 4B and 5 in particular, it will be seen that the plunger rod 200 is hollow, at least at the distal end 402, and that the rear cap 112 has a guide post 500 extending in the proximal direction. The distal end 402 of the plunger rod 200 is arranged to be mounted on the guide post 500 of the rear cap 112. Specifically, the guide post 500 fits inside the distal end 402 of the plunger rod 200. Moreover, the guide post 500 and the distal end 402 of the plunger rod 200 have a corresponding slot 502 and ridge 404 that cooperate with one another to prevent rotation of the plunger rod 200 relative to the guide post 500 when the plunger rod 200 is mounted on the guide post 500. In this way, with the rear cap 112 secured to the housing 106 of the drive assembly 102, the plunger rod 200 is generally prevented from rotating relative to the rest of the drive assembly 102. In the illustrated embodiment, two ridges 404 are provided inside the plunger rod 200, facing radially inwards, and two corresponding slots 502 are provided on the guide post 500, facing radially outwards, but other arrangements are possible. Tabs 406 are provided along the length of the plunger rod 200. Each tab 406 extends radially outwards and has a distally facing surface 408 that allows the plunger rod 200 to be pushed in the proximal direction by the rotator 204, as described in more detail below. The distally facing surface 408 is typically flat and perpendicular to the length of the plunger rod 200, and, e.g., the longitudinal axis A of the drive assembly 102, in use.

The tabs 406 are arranged to cooperate with a retainer 602 of the rotator 204, as described in more detail below. Specifically, referring to Figs. 4C and 4D in particular, an edge 410 of the tabs 406 is arranged to be captured by the rotator 204. In the illustrated embodiment, this involves a snap fit arrangement. For this purpose, the edge 410 is bordered by a first surface 412 towards the distal end 108 of the drive assembly 102, which first surface 412 slopes radially inwards away from the edge 110 in the distal direction to provide a cam surface to assist with the capture. The edge 410 is also bordered by a second surface 414 towards the proximal end 110 of the drive assembly 102, which second surface 414 is inclined away from the edge 110 perpendicularly or acutely to provide a retaining surface to assist with the capture. In other words, the second surface 414 extends radially inwards from the edge 410, e.g. perpendicularly to the longitudinal axis A of the drive assembly 102, or undercuts the edge 410.

The tabs 406 are arranged in groups. In the illustrated embodiment, there are two tabs 406 in each group of tabs. The tabs 406 of each group are located at the same position along the length of the plunger rod 200, but offset from one another circumferentially. In particular, the distally facing surfaces 408 of the tabs 704 in a respective group of tabs may be generally co-planar, e.g. extend in a single imaginary plane. In the illustrated embodiment there are two tabs 406 in each group of tabs. The tabs 406 of each group are offset from one another circumferentially by 180 degrees, e.g. opposite to one another around the circumference. In other embodiments, the groups of tabs have other numbers of tabs 406, e.g. just one tab 406, or generally between 1 and 4 tabs 406. Also, in the illustrated embodiment, there are 3 groups of tabs. The most distal of the groups of tabs is referred to as the first group of tabs, the most proximal of the groups of tabs is referred to as the third group of tabs and the group of tabs between the most distal and most proximal groups of tabs is referred to as the second group of tabs. Individual tabs 704 in the first, second and third groups of tabs may similarly be referred to as first tab, second tab and third tab respectively in common with the group to which they belong. The first, second and third groups of tabs correspond to the first, second and third axial positions of the rotator 204 and are utilized in first, second and third configurations of the medicament delivery device 100 respectively, as described in more detail below. Referring to Fig. 4D in particular, the plunger rod 200 also has a return protrusion 416. The return protrusion 416 is located along the length of the plunger rod 200 proximally relative to the tabs 406. In the illustrated embodiment, the return protrusion 416 extends radially outwards from the plunger rod 200 further than the tabs 406, and there are two return protrusions 416 located at the same position along the length of the plunger rod 200, but offset from one another circumferentially by 180 degrees (similarly to the tabs 704 of each group of tabs), but other arrangements are possible.

A proximally facing surface 418 is also provided on the plunger rod 200. The proximally facing surface 418 may be used to push the plunger rod 200 in the distal direction, typically during returning the plunger rod 200 to its initial position as described in more detail below. In the illustrated embodiment, the proximally facing surface 418 is provided on the return protrusion 416, but in other embodiments the proximally facing surface 418 may be provided elsewhere on the plunger rod 200, e.g. on another protrusion.

Referring to Fig. 6, the rotator 204 is generally cylindrical and arranged to be mounted on the plunger rod 200. The rotator 204 has bearing surfaces 600 that correspond to the outer surface of the plunger rod 200. When the rotator 204 is mounted to the plunger rod 200 the bearing surfaces 600 ride against the outer surface of the plunger rod 200 to allow relative movement, including rotation, between the rotator 204 and the plunger rod 200.

The rotator 204 has a proximally facing surface 608 at a proximal end of the rotator 204. The proximally facing surface 608 is generally flat and extends perpendicularly to the longitudinal axis A of the drive assembly 102. The proximally facing surface 608 is arranged to cooperate with the distally facing surfaces 408 of the tabs 406 of the plunger rod 200. The proximally facing surface 608 also incorporates a gap 610. Indeed, in the illustrated embodiment the proximally facing surface 608 incorporates two gaps 610. The/each gap 610 is arranged to allow the tabs 406 of the plunger rod 200 to pass through the proximally facing surface 608. That is, the dimensions of each gap 610 are large enough to allow a tab 406 to pass through. The rotator 204 has a first rotational orientation relative to the plunger rod 200, in which first rotational orientation the gap or gaps 610 of the proximal end surface 608 overlap tabs 406 of the plunger rod 200 such that the plunger rod 200 may move distally relative to the rotator 204. The rotator 204 also has a second rotational orientation relative to the plunger rod 200, in which first rotational orientation the gap or gaps 610 of the proximal end surface 608 are offset from the tab or tabs 406 of the plunger rod 200 such that the tab or tabs 406 of the plunger rod rest against the proximally facing surface 608 and provide for the rotator 204 to urge the plunger rod 200 in a proximal direction. The rotator 204 has the retainer 602 at a proximal end. The retainer 602 comprises an arm 604 extending in the proximal direction, which arm 604 has a protrusion 606 extending radially inwards (relative to the longitudinal axis A) at a proximal end of the arm 604 (furthest from the rest of the rotator 204). The arm 604 is flexible, in that it is arranged to allow the protrusion 606 to be deflected radially outwards (relative to the longitudinal axis A). The protrusion 606 provides a distally facing surface 616 arranged to cooperate with one of the tabs 406 of the plunger rod 200 to hold the tab 406 between the protrusion 606 and the proximally facing surface 608 of the rotator 204 to prevent the plunger rod 200 from moving relative to the rotator 204 in the proximal direction. Indeed, in the illustrated embodiment, the distally facing surface 616 of the protrusion 606 and the proximally facing surface 608 of the rotator 204 are arranged to be able to hold the tab 406 between the protrusion 606 and the rotator 204 to prevent the plunger rod 200 from moving axially relative to the rotator 204 (distally or proximally). The protrusion 606 also has a proximally facing surface 618 arranged to ride on the one of the tabs 406 of the plunger rod 200 as the plunger rod 200 moves towards the rotator 204 in the distal direction. The distally facing surface 616 is generally perpendicular to the longitudinal axis A of the drive assembly 102, such that it prevents movement of the plunger rod 200 in the proximal direction relative to the rotator 204 by blocking the path of the tab 406 of the plunger rod 200. The proximally facing surface 618 generally slopes radially inwards in the distal direction such that the protrusion 606 is deflected radially outwards as the tab 406 of the plunger rod 200 rides over the proximally facing surface 618 in the distal direction, until the tab 406 reaches a distal end of the proximally facing surface 618 and the protrusion 606 moves radially inwards to capture the tab 406 of the plunger rod 200. This arrangement can be described as a snap fit. In the illustrated embodiment, there are two arms 604 each having a protrusion 606. The arms 604 and protrusions 606 are offset circumferentially from one another by 180 degrees. Each protrusion 606 is arranged to interact with one of the tabs 406 of the same group of tabs, such that both/al I the tabs 406 of the group of tabs are retained by the retainer 602. In other embodiments, the retainer 602 may retain the plunger rod 200 using mechanisms other than the snap fit arrangement described above, and/or different numbers of arms 604 and protrusions 606 may be provided.

A ramp 612 is provided on the rotator 204. The ramp 612 is arranged to cooperate with the actuator 206 to cause the rotator 204 to rotate around the longitudinal axis A of the drive assembly 102 as the actuator 206 moves in the distal direction, as described in more detail below. The ramp 612 extends around the rotator 204 obliquely to the axial direction. The slope of the ramp 612 is that of a right-handed thread. In the illustrated embodiment, the ramp 612 is provided on an outer surface of a side wall of the rotator. Specifically, the ramp 612 is provided by a ridge upstanding from the outer surface. In the illustrated embodiment, there are two ramps 612, although only one is visible in Fig. 6. The ramps 612 are offset circumferentially from one another by 180 degrees, that is they are on opposite sides of the rotator 204.

An additional ramp 613 is also provided on the rotator 204. The additional ramp 613 is arranged to cooperate with the actuator 206 to cause the rotator 204 to rotate around the longitudinal axis A of the drive assembly 102 as the actuator 206 moves in the proximal direction, as described in more detail below. The additional ramp 613 extends around the rotator 204 obliquely to the axial direction. The slope of the additional ramp 613 is that of a left-handed thread. The additional ramp 613 is located proximate to a proximal end of the ramp 612 and is arranged to ensure that the rotator 204 is properly aligned with the actuator 206, as described in more detail below. In the illustrated embodiment, the additional ramp 613 is provided on an outer surface of a side wall of the rotator 204. Specifically, the additional ramp 612 is provided by a ridge upstanding from the outer surface. In the illustrated embodiment, there are two additional ramps 613, although only one is visible in Fig. 6. The additional ramps 613 are offset circumferentially from one another by 180 degrees, that is they are on opposite sides of the rotator 204.

At its distal end, the rotator 204 has a protrusion 614. The protrusion 614 is arranged to cooperate with the housing 106 of the drive assembly 102 and forms part of a retaining arrangement and a resetting arrangement, as described in more detail below. The protrusion 614 extends radially outwards from the rotator 204, specifically from the outer surface of the side wall of the rotator 204, e.g. towards the housing 106.

Referring back to Fig. 2, it will be seen that the drive member 202, which in the illustrated embodiment is a compression spring, is located at least partially within the rotator 204. Specifically, a proximal end of the drive member 202 abuts a distally facing surface of the rotator 204, which distally facing surface in the illustrated embodiment is towards the proximal end of the rotator 204. A distal end of the drive member 202 abuts the end cap 112. The drive member 202 is compressed between the distally facing surface of the rotator 204 and the end cap 112 in the first configuration of the drive assembly 102, and becomes progressively less compressed in the subsequent configurations. It will also be seen that, at least in the illustrated embodiment, the drive member 202 is located radially between the rotator 204 and the plunger rod 200 and/or guide post 500 of the end cap 112. It is also concentrically located with the longitudinal axis A of the drive assembly 102. This allows the drive member 202 to be held stabling within the drive assembly 102.

Referring to Fig 7, the actuator 206 has a proximal portion 700, which in the illustrated embodiment is generally cylindrical, and a distal portion in the form of two arms 702 that extend from the proximal portion 700 in the distal direction. The arms 702 are provided with protrusions 704 that extend radially inwardly from an inwardly facing surface of the arms 702. The protrusions 704 are at different positions along the length of the actuator 206, each axial position corresponding to a different configuration of the medicament delivery device 100. In the illustrated embodiment, each arm 702 has 3 protrusions at 3 different axial positions corresponding with 3 different configurations of the of the medicament delivery device 100, but in other embodiments different numbers of protrusions 704, axial positions and configurations are possible. The protrusions 704 of each respective arm 702 are located at the same circumferential position. The protrusions 704 are positioned such that, when the actuator 206 and rotator 204 are assembled in the housing 106 of the drive assembly 102, the protrusions 704 may contact the ramp 612 and the additional ramp 614, as described in more detail below. For convenience, in the illustrated embodiment, the most distal protrusion 704 on each arm 702 is referred to as the first protrusion 704, the most proximal protrusion 704 on each arm 702 is referred to as the third protrusion 704 and the protrusion 704 between the most distal and most proximal protrusions 704 is referred to as the second protrusion 704. The first, second and third protrusions 704 are utilized in first, second and third configurations of the medicament delivery device 100 respectively, as described in more detail below.

The arms 702 of the actuator 206 also have guides 706 arranged to cooperate with the housing 106 of the drive assembly 102 to prevent relative rotation of the actuator 206 and housing 106. In the illustrated embodiment, the guides 706 are in the form of slots. The guides 706 are provided on an outwardly facing surface of the arms 702. In the illustrated embodiment, each arm has 3 guides 706 at different axial positions corresponding with the axial positions of the protrusions 704, but other arrangements are possible, such as just one slot extending most of the length of the arm 702.

Referring to Figs. 8A to 8C, the housing 106 has a rib 800 that cooperates with the guides 706 of the actuator 206 to prevent relative rotation of the actuator 206 and the housing 106. In the illustrated embodiment, there are two ribs 800 each for cooperating with one of the two arms 702 of the actuator 206. The ribs 800 are located on an inwardly facing side wall of the housing 106 and extend parallel to the longitudinal axis A of the drive assembly 102.

The housing 106 also has elements of a retaining arrangement and a resetting arrangement, which are described in more detail below. Specifically, in relation to the retaining arrangement, the housing 106 has a circumferentially extending surface 802 for retaining the rotator 204 in an axial position. The circumferentially extending surface 802 is arranged such that the protrusion 614 of the rotator 204 may ride against the circumferentially extending surface 802 when the rotator 204 is in the axial position. The protrusion 614 is located distally of the circumferentially extending surface 802 at this stage. The circumferentially extending surface 802 faces in the distal direction. The circumferentially extending surface 802 only extends over a portion of the circumference of the housing 106. This means that the rotator 204 is only retained in the axial position at some orientations of the rotator 204 relative to the housing 106, as described in more detail below. It can be seen that the housing 106 has three such circumferentially extending surfaces 802 in the illustrated embodiment. The most distal of the circumferentially extending surfaces 802 is referred to as the first circumferentially extending surface 802, the most proximal circumferentially extending surface 802 is referred to as the third circumferentially extending surface 802 and the circumferentially extending surface 802 between the most distal and most proximal circumferentially extending surface 802 is referred to as the second circumferentially extending surface 802. The first, second and third circumferentially extending surfaces 802 correspond to the first, second and third axial positions of the rotator 204 and are utilized in first, second and third configurations of the medicament delivery device 100 respectively, as described in more detail below.

In relation to the resetting arrangement, the housing 106 is provided with a ramp 804 for resetting the rotator 204 as it moves between the axial positions. The ramp 804 extends between the axial positions, and obliquely to the longitudinal axis A of the drive assembly 102 or the axial direction. The slope of the ramp 804 of the housing 106 is that of a left-handed thread. The circumferential extent of the ramp 804 is the same as the circumferential extent of the circumferentially extending surface 802. It can be seen that the housing 106 has two such ramps 804 in the illustrated embodiment. The most distal of the ramps 804 is referred to as the first ramp 804, the most proximal ramp 804 is referred to as the second ramp 804. The first ramp 804 is utilized as the rotator 204 moves between the first and second axial positions or as the medicament delivery device 100 is between the first and second configurations, and the second ramp 804 is utilized as the rotator 204 moves between the second and third axial positions or as the medicament delivery device 100 is between the second and third configurations, as described in more detail below.

It can also be seen from Figs. 8A to 8C that the flexible arms 114 of the housing 106 each have retaining element 806. In the illustrated embodiment, the retaining element 806 is in the form of an inwardly facing protrusion. The retaining element 806 is arranged to engage with the return protrusion 416 of the plunger rod 200 and with the traveler 210. Specifically, the retaining element 806 has a distally facing surface 810 for cooperating with the return protrusion 416 and a proximally facing surface 808 for cooperating with the traveler 210, as described in more detail below. The distally facing surface 810 slopes radially inwards in the proximal direction such that as the plunger rod 200 moves in the proximal direction, the return protrusion 416 rides over the distally facing surface 810 and deflects the retaining element radially outwards by causing the flexible arm 114 to flex. The proximally facing surface 810 extends radially inwards generally perpendicularly to longitudinal axis A of the drive assembly 102. When the retaining element 806 is in a first position, which is before any interaction with the return protrusion 416 or relatively radially inwards, the retaining element 806 prevents movement of the traveler 210 in the distal direction. For example, in the illustrated embodiment, the proximally facing surface 808 is positioned against a distally facing surface 904 of the traveler 210 (see Fig. 9), e.g. blocking the path of the traveler 210. When the retaining element 806 is in a second position, which is after interaction with the return protrusion 416 or relatively radially outwards, the retaining element 806 releases the traveler 210 for movement in the distal direction. For example, in the illustrated embodiment, the distally facing surface 808 is positioned away from the distally facing surface 904 of the traveler, e.g. radially outwards of the distally facing surface 904 and no longer blocking the path of the traveler 210.

Referring to Fig. 9, it can be seen that the traveler 210 is generally ring-shaped. The distally facing surface 904 arranged to cooperate with the return protrusion 416 of the plunger rod 200 is an end wall of the traveler 210. The traveler 210 is also approximately as wide and the internal diameter of the housing 106, such that the traveler 210 is accommodated stably by the housing 106 and can engage with the retaining element 806 of the housing 106. The traveler 210 also has a cut-out 900 for receiving an end of the biasing element 208, such that the traveler 210 and the biasing element 208 are secured to one another. In more detail, in the illustrated embodiment, the biasing element 208 is a compression spring with a hooked end 902. This hooked end can engage with the cut-out 900 to secure the biasing element 208 to the traveler 900. The other end of the biasing element 208 is located against a distally facing surface of the actuator 206. In more detail, a recess 708 is provided by the proximal portion 700 of the actuator 206 for similarly securing the biasing element 208 to the actuator 206. In this way, the biasing element 208 biases the traveler 210 in the distal direction. It also biases the actuator 206, and consequently the delivery member cover 118 when the removable cassette 104 is mounted to the drive assembly 104, in the proximal direction.

In operation, the medicament container 120, e.g. containing a medicament to be delivered to the user or to a patient under the care of the user, is mounted in the removeable cassette 104. This involves inserting the medicament container 120 into the medicament container carrier 116. The medicament container 120 is inserted into the medicament container carrier 116 from the distal end of the medicament container carrier 116. When the medicament container 120 is fully inserted into the medicament container carrier 116, a flange 1000 of the medicament container 120 is held by a flange holder 1002 of the medicament container carrier 116. This prevents the medicament container 120 from falling out of the medicament container carrier 116, and the removeable cassette 104, accidentally. The assembly of the medicament container 120 to the medicament container carrier 116 and the removeable cassette 104 may be carried out in bulk, e.g. many such assemblies may be assembled in an assembly facility for supply to end users, so the end user is provided with the removable cassette 104 already accommodating the medicament container 120.

Taking a removeable cassette 104 in which a medicament container 120 is accommodated, the removeable cassette 104 may mounted to the drive assembly 102. This may be carried out by an end user, and involves inserting the distal end of the removable cassette 104 into the proximal end of the drive assembly 102. In particular, the distal end of the delivery member cover 118 is inserted into the proximal end of the actuator 206.

Referring to Figs. 10A to 10C, the attachment mechanism is manipulated such that the removable cassette 104 is locked to the drive assembly 102. In more detail, the removable cassette 104 is inserted into the drive assembly 102 until the attachment mechanism is axially aligned. The removable cassette 104 is then rotated relative to the drive assembly 102 around the longitudinal axis A of the medicament delivery device 100. In the illustrated embodiment the rotation of the removable cassette 104 is clockwise when viewed from the proximal end, as shown by arrow C in Fig. 10B. This causes the attachment mechanism to lock the removable cassette 104 to the drive assembly 102. More specifically, the rotation causes the protrusion 300 of the removeable cassette 104 to engage with the recess 302 of the drive assembly 102, or in the illustrated embodiment the ridges to slide into the slots via the open ends 304 of the slots. It should be noted that in this position the arms 124 of the medicament container holder 116 engage a proximal end surface of the housing 106 of the drive assembly 102. This helps to ensure that the medicament container holder 116 and medicament container 120 are not inserted too far into the drive assembly 102.

Referring to Fig. 11, the first time a removable cassette 104 is mounted to the drive assembly 102, the medicament delivery device 100 becomes ready for use, e.g. for delivery the medicament to the user, without any additional steps. At this stage, the medicament delivery device 100 is in the first configuration. In the first configuration, the rotator 204 is at the first axial position and in the first rotational orientation. The protrusion 614 of the retaining arrangement is riding against the first circumferentially extending surface 802 of the retaining arrangement to retain the rotator 204 at the first axial position. The first group of tabs of the plunger rod 200 are retained by the retainer 602 of the rotator 204 (Fig. 12B). The first group of tabs of the plunger rod 200 are also aligned with the gap 610 in the distally facing surface 608 of the rotator 204 (Fig. 12C), although in the illustrated embodiment this is of no consequence whilst the rotator 204 in in the first axial position. The retaining element 806 is in the first position such that the traveler 210 is prevented by the retaining element 806 from moving in the distal direction (Fig. 12C). This ensures that the actuator 206 and delivery member cover 118 are biased in the proximal direction, and that the actuator 206 is ready to move in the proximal direction to cause rotation of the rotator 204 (Fig. 12D).

Referring to Fig. 13, when the user is ready for the medicament delivery device 100 to deliver the medicament, the user removes the cap 122 from the removable cassette 104. Removing the cap 122 causes the delivery member shield remover 216 simultaneously to remove the delivery member shield 218 from the medicament container 120. The cap 122, delivery member shield remover 216 and delivery member shield 218 may then be placed to one side. The user may then activate the medicament delivery device 100 by pressing the proximal end of the delivery member cover 118 against the location, e.g. on the user's body, at which the medicament is to be delivered. This causes the delivery member cover 118 to move axially in the distal direction relative to the medicament container 120 to expose the delivery member 1300, which may consequently penetrate the user's body. The axial movement in the distal direction of the delivery member cover 118 causes the actuator 206 also to move axially in the distal direction relative to the housing 106 of the drive assembly 102 and relative to the rotator 204, against the force of the biasing element 208, e.g. compressing the delivery member cover compression spring in the illustrated embodiment.

The axial movement of the actuator 206 in the distal direction causes the rotator 204 to rotate from the first rotational orientation to the second rotational orientation. The rotation of the rotator 204 is in the counterclockwise direction when viewed from the proximal end, as illustrated by arrow D in Fig. 13. In more detail, the protrusion 704 of the actuating arrangement rides against the ramp 612 of the rotator 204 to urge the rotator 204 to rotate from the first rotational orientation to the second rotational orientation (Fig. 14A). The protrusion 704 rides along the ramp 612 from the proximal end of the ramp 612 to the distal end of the ramp 612 until the protrusion 704 clears or moves beyond the distal end of the ramp 612. As the rotator 204 rotates from the first rotational orientation to the second rotational orientation, the protrusion 614 of the retaining arrangement riding along the first circumferentially extending surface 802 of the retaining arrangement (from the position shown in Fig. 14B) until it reaches the end of the first circumferentially extending surface 802 and the rotator 204 is released from the retaining arrangement for movement in the proximal direction (Fig. 14C).

With the rotator 204 in the second rotational orientation, the rotator 204 is free to move in the proximal direction from the first axial position under the force applied to it by the drive member 202. Moreover, in the second rotational orientation, the first group of tabs of the plunger rod 200 are aligned with the distally facing surface 608 of the rotator 204 (instead of with the gap 610 in the distally facing surface 608) (Fig. 14D). This results in the distally facing surface 608 transferring force from the drive member 202 to the first group of tabs as the rotator 204 moves in the proximal direction. In other words, the movement of the rotator 204 in the proximal direction causes movement of the plunger rod 200 in the proximal direction.

Referring to Fig. 15, as the rotator 204 moves in the proximal direction from the first axial position, the resetting arrangement causes the rotator 204 to rotate from the second rotational orientation to the first rotational orientation. In the illustrated embodiment, this rotation is in the opposite direction to the rotation from the first rotational orientation to the second rotational orientation caused by the actuating arrangement. Indeed, in the illustrated embodiment, the rotation caused by the actuating arrangement is counterclockwise when viewed along the axis from the proximal end, and the rotation caused by the resetting arrangement is clockwise when viewed similarly. As the protrusion 704 has moved beyond the distal end of the ramp 612 of the rotator 204, the rotator 204 is free to rotate back from the second rotational orientation to the first rotational orientation.

However, in other embodiments, the rotator 204 may be arranged to continue to rotate in the same direction, e.g. initially from the first rotation to the second rotation and subsequently from the second rotation to the first orientation in the same direction.

The actual movement of the rotator 204, combining the axial movement under the force of the drive member 202 and the clockwise rotation caused by the resetting arrangement, is illustrated by arrow E in Fig. 15 and is generally helical. In more detail, operation of the resetting arrangement involves the protrusion 614 of the resetting arrangement riding against the ramp 804 of the housing 106 such that movement of the rotator 802 axially in the proximal direction forces the protrusion 614 along the ramp 804 and the rotator 204 to rotate from the second rotational orientation to the first rotational orientation (Fig. 16A). As previously described, in the illustrated embodiment, the protrusion 614 of the resetting arrangement is the same component as the protrusion 614 of the retaining arrangement, although in other embodiments two separate protrusions or some other arrangement may be utilized.

The resetting arrangement is configured such that the rotator 204 generally arrives at the first rotational orientation at the same time as arriving at the second axial position, although in the illustrated embodiment the rotator 204 actually arrives at an interim rotational orientation under action of the protrusion 614 and the ramp 804 of the housing 106 at the end of the axial movement of the rotator then subsequently moves to the first rotational orientation under action of the protrusion 704 of the actuator 206 and the additional ramp 613 of the rotator. The length of travel between the first and second axial positions corresponds to the length of travel of the plunger rod 200 required to cause the piston 220 of the medicament container 120 to travel sufficiently within the medicament container 120 to expel the required dose of the medicament (e.g. substantially all the medicament in the medicament container 120) from the medicament container 120. As the rotator 204 reaches the second axial position and the first rotational orientation, the first group of tabs become aligned with the gap 610 in the distally facing surface 608 of the rotator 204 (Fig. 16B), and the plunger rod 200 is released to move axially in the distal direction (by the first group of tabs passing through the gap 610 in the distally facing surface 608). Moreover, the protrusion 614 of the retaining arrangement is riding against the second circumferentially extending surface 802 of the retaining arrangement to retain the rotator 204 at the second axial position.

Movement of the plunger rod 200 in the distal direction occurs by operation of the return mechanism. In more detail, when the plunger rod 200 has been moved in the proximal direction by the rotator 204 moving from the first axial position to the second axial position, the return protrusion 416 of the plunger rod cooperates with the retaining element 806 to cause the retaining element 806 to move from the first position to the second position. In the second position, the retaining element 806 releases the traveler 210 to move in the distal direction, e.g. because of the biasing provided to the traveler 201 by the biasing element 208 (Fig. 16C). The traveler 210 cooperates with the proximally facing surface 418 of the plunger rod 200 to push the plunger rod 200 in the distal direction as the traveler 210 moves in the distal direction (as illustrated by arrows F and G in Figs. 17 and 18A respectively). The return mechanism causes the plunger rod 200 to move back to the same position as it was prior to delivery of the medicament, e.g. the initial position of the plunger rod 200. Specifically, the axial positions of the plunger rod 200 prior to delivery of the medicament and after delivery of the medicament and resetting of the drive assembly 102 are the same. This means that the proximal end of the plunger rod 200 is in the correct position to be able to accommodate, and cause delivery of medicament from, another removeable cassette 104 when the used removeable cassette 104 is replaced. However, the rotator 204 is now in the second axial position. With the rotator 204 in the second axial position and the plunger rod 200 in its initial position, the second group of tabs of the plunger rod 200 are retained by the retainer 602 of the rotator 204 (Fig. 18B).With the medicament having been delivered and the plunger rod 200 returned to the initial position, the removable cassette 104 may be removed from the drive assembly 102. Specifically, the removeable cassette 104 is pulled in the proximal direction, away from the drive assembly 102, by the user (as illustrated by arrow H in Fig. 19). The delivery member cover 18 and actuator 206 to move in the proximal direction to their initial positions, and the biasing member 208 pulls the traveler 210 in the proximal direction until the traveler 210 in its initial position (as illustrated by arrow I in Fig. 19). In the initial position of the traveler 210, the retaining element 806 located on the flexible arm 114 of the housing 106 again cooperates with the traveler 210 to prevent the traveler 210 from moving in the distal direction.

As the actuator 206 moves to its initial position, the protrusion 704 may engage with the additional ramp 613 of the rotator 204. The protrusion rides along the additional ramp 613 in the proximal direction, and the rotator 204 is caused to rotate clockwise as viewed from the proximal end 110 of the drive assembly 106. This rotation is small in comparison to the rotation from the first rotational orientation to the second rotational orientation. It is provided to ensure that the protrusion 704 is aligned with the proximal end of the ramp 612 ready for distal movement of the actuator 206 during delivery of the medicament on the next occasion. It will be appreciated that the protrusion 704 and the additional ramp 613 are part of the resetting arrangement in the illustrated embodiment, in the sense that the rotator 204 only eventually arrives at the first rotational orientation after the protrusion 704 has ridden on the additional ramp 613 during movement of the actuator in the proximal direction. However, in other embodiments, e.g. embodiments in which multiple ramps 612 are provided on the rotator 204 or the rotation continues to rotates in the same direction as the rotator 204 moves from the first rotational orientation to the second rotational orientation and from the second rotational orientation to the first rotational orientation, the additional ramp 613 may not be needed. It should also be noted that even in the rotational orientation of the rotator 204 that is reached after the axial movement of the rotator 204 in the proximal direction and before axial movement of the actuator 206 in the proximal direction, the gap 610 in the proximally facing surface 608 of the rotator 204 is aligned with the tab 406 of the plunger rod 200 to allow distal movement of the plunger rod, although in other embodiments this may only be achieved after movement of the actuator 206 in the proximal direction.

With the delivery member cover 118 and actuator 206 in their initial positions, the removable cassette 104 may be rotated to disengage the attachment mechanism. Specifically, the removable cassette 104 is rotated relative to the drive assembly 102 around the longitudinal axis A of the medicament delivery device 100 in the opposite direction to the direction of the rotation during attachment of the removeable cassette 104 to the drive assembly 102. In the illustrated embodiment, the rotation of the removable cassette 104 is clockwise during attachment when viewed from the proximal end and counterclockwise during removal when viewed similarly. During removal, the rotation causes the protrusion 300 of the removeable cassette 104 to move out of the recess 302 of the drive assembly 104.

With the removable cassette 104 removed from the drive assembly 102, the drive assembly 102 is ready to be used with a new removable cassette. No further action is required to prepare the drive assembly 102. The new removeable cassette 104 is simply mounted to the drive assembly 102 in the same way as the previous removable cassette 104 was mounted. Again, the distal end of the removable cassette 104 is inserted into the proximal end of the drive assembly 102 and the attachment mechanism is manipulated such that the removable cassette 104 is locked to the drive assembly 102.

At this stage, the medicament delivery device is in the second configuration (like that shown in Fig. 19). In the second configuration, the rotator 204 is at the second axial position and in the first rotational orientation. The protrusion 614 of the retaining arrangement is riding against the second circumferentially extending surface 802 of the retaining arrangement to retain the rotator 204 at the second axial position. The second group of tabs of the plunger rod 200 are retained by the retainer 602 of the rotator 204. The second group of tabs of the plunger rod 200 are also aligned with the gap 610 in the distally facing surface of the rotator 204. The retaining element 806 is in the first position such that the traveler 210 is prevented by the retaining element 806 from moving in the distal direction, and the delivery member cover 118 and the actuator 206 are biased in the proximal direction.

When the user is ready for the medicament delivery device 100 to deliver the medicament, the user again removes the cap 122 from the removable cassette and activates the medicament delivery device 100 by pressing the proximal end of the delivery member cover 118 against the location at which the medicament is to be delivered. The consequential axial movement of the actuator 206 in the distal direction again causes the rotator 204 to rotate from the first rotational orientation to the second rotational orientation. However, with the rotator 204 now in the second axial position, it is the second protrusion 704 of the actuating arrangement that rides against the ramp 612 of the rotator 204 to urge the rotator 204 to rotate from the first rotational orientation to the second rotational orientation. Similarly, the protrusion 614 of the retaining arrangement arrives at the end of the second circumferentially extending surface 802 of the retaining arrangement to release the rotator 204 to move axially in the proximal direction from the second axial position.

With the rotator 204 in the second rotational orientation, it is now the second group of tabs of the plunger rod 200 that is aligned with the distally facing surface 608 of the rotator 204. This results in the distally facing surface 608 transferring force from the drive member 202 to the second group of tabs of the plunger rod 200 as the rotator 204 moves axially in the proximal direction.

As the rotator 204 moves in the proximal direction from the second axial position, the resetting arrangement again causes the rotator 204 to rotate from the second rotational orientation to the first rotational orientation. However, in the illustrated embodiment, the protrusion 614 of the resetting arrangement now rides against the second ramp 804 of the resetting arrangement to cause the rotator 204 to rotate from the second rotational orientation to the first rotational orientation. Similarly, it is the second protrusion 704 of the actuator that rides on the additional ramp 613 of the rotator as the actuator 206 subsequently moves in the proximal direction, e.g. when the removable cassette 104 is replaced.

Similarly to before, the resetting arrangement is configured such that the rotator 204 generally arrives at the first rotational orientation at the same time as arriving at the third axial position, similarly to during the use of the first removable cassette 104. The length of travel between the second and third axial positions corresponds to the length of travel of the plunger rod 200 required to cause the piston 220 of the medicament container 120 to travel sufficiently within the medicament container 120 to expel the required dose of the medicament from the medicament container 120. As the rotator 204 reaches the third axial position and the first rotational orientation, the second group of tabs of the plunger rod 200 becomes aligned with the gap 210 in the distally facing surface 208 of the rotator 204, and the plunger rod 200 is released to move axially in the distal direction (by the second group of tabs passing through the gap 610 in the distally facing surface 608 of the rotator 204). Moreover, the protrusion 614 of the retaining arrangement is riding against the third circumferentially extending surface 802 of the retaining arrangement to retain the rotator 204 at the third axial position.

Movement of the plunger rod 200 in the distal direction again occurs by operation of the return mechanism. When the plunger rod 200 has been moved in the proximal direction by the rotator 204 moving from the second axial position to the third axial position, the return protrusion 416 of the plunger rod 200 cooperates with the retaining element 806 to cause the retaining element 806 to move from the first position to the second position. In the second position, the retaining element 806 releases the traveler 210 to move in the distal direction. The traveler 210 cooperates with the proximally facing surface 418 of the plunger rod 200 to push the plunger rod 200 in the distal direction as the traveler 210 moves in the distal direction. The return mechanism causes the plunger rod 200 to move back to the same position as it was prior to delivery of the medicament. However, the rotator 204 is now in the third axial position. With the rotator 204 in the third axial position and the plunger rod 200 in its initial position, the third group of tabs of the plunger rod is now retained by the retainer 602 of the rotator 204.

With the medicament having been delivered and the plunger rod 200 returned to the initial position, the removable cassette 104 may be removed from the drive assembly 102. This follows the same procedure as removal of the previous removable cassette 102. With the removable cassette 104 removed from the drive assembly 102, the drive assembly 102 is ready to be used with a third removable cassette 104. Again, no further action is required to prepare the drive assembly 102. The third removeable cassette 104 is mounted to the drive assembly 102 in the same way as the first and second removable cassettes 104 were mounted. Again, the distal end of the removable cassette 104 is inserted into the proximal end of the drive assembly 102 and the attachment mechanism is manipulated such that the removable cassette 104 is locked to the drive assembly.

At this stage, the medicament delivery device is in the third configuration, as shown in Fig 20. In the third configuration, the rotator 204 is at the third axial position and in the first rotational orientation. The protrusion 614 of the retaining arrangement is riding against the third circumferentially extending surface 802 of the retaining arrangement to retain the rotator 204 at the third axial position. The third group of tabs of the plunger rod 200 is retained by the retainer 602 of the rotator 204. The second group of tabs of the plunger rod 200 are also aligned with the gap 610 in the distally facing surface 608 of the rotator 204. The retaining element 806 is in the first position such that the traveler 210 is prevented by the retaining element 806 from moving in the distal direction, and the delivery member cover 118 and the actuator 206 are biased in the proximal direction.

When the user is ready for the medicament delivery device 100 to deliver the medicament, the user again removes the cap 122 from the removable cassette 104 and activates the medicament delivery device 100 by pressing the proximal end of the delivery member cover 118 against the location at which the medicament is to be delivered. The consequential axial movement of the actuator 206 in the distal direction again causes the rotator 204 to rotate from the first rotational orientation to the second rotational orientation. However, with the rotator 204 now at the third axial position, it is the third protrusion 704 of the actuating arrangement that rides against the ramp 612 of the rotator 204 to urge the rotator 204 to rotate from the first rotational orientation to the second rotational orientation. Similarly, the protrusion 614 of the retaining arrangement arrives at the end of the third circumferentially extending surface 802 of the retaining arrangement to release the rotator 204 to move axially in the proximal direction from the third axial position.

With the rotator 204 in the second rotational orientation, it is now the third group of tabs of the plunger rod 200 that is aligned with the distally facing surface 608 of the rotator 204. This results in the distally facing surface 608 transferring force from the drive member 202 to the third group of tabs as the rotator 204 moves axially in the proximal direction. As the rotator 204 moves in the proximal direction from the third axial position, the resetting arrangement has no function. It is of no consequence whether the rotator 204 moves from the second rotational orientation to the first rotational orientation at this stage, because, in the illustrated embodiment, the drive assembly 102 is only designed to be reused 3 times. Specifically, the drive member 202 is no longer sufficiently compressed to drive the plunger rod 200 a fourth time and the plunger rod 200 cannot be reset after the third use of the drive assembly 102.

However, the skilled person will understand that it is perfectly possible for the drive assembly 102 to be arranged to be reused different number of times in other embodiments. Typically, reuse between 2 to 10 times might be possible by having appropriate numbers of groups of tabs on the plunger rod 200 and a corresponding number of axial positions for the rotator 204.

The medicament delivery devices described herein can be used for the treatment and/or prophylaxis of one or more of many different types of disorders.

Exemplary disorders include, but are not limited to: rheumatoid arthritis, inflammatory bowel diseases (e.g. Crohn's disease and ulcerative colitis), hypercholesterolaemia and/or dyslipidemia, cardiovascular disease, diabetes (e.g. type 1 or 2 diabetes), psoriasis, psoriatic arthritis, spondyloarthritis, hidradenitis suppurativa, Sjogren's syndrome, migraine, cluster headache, multiple sclerosis, neuromyelitis optica spectrum disorder, anaemia, thalassemia, paroxysmal nocturnal hemoglobinuria, hemolytic anaemia, hereditary angioedema, systemic lupus erythematosus, lupus nephritis, myasthenia gravis, Behget's disease, hemophagocytic lymphohistiocytosis, atopic dermatitis, retinal diseases (e.g., age-related macular degeneration, diabetic macular edema), uveitis, infectious diseases, bone diseases (e.g., osteoporosis, osteopenia), asthma, chronic obstructive pulmonary disease, thyroid eye disease, nasal polyps, transplant, acute hypoglycaemia, obesity, anaphylaxis, allergies, sickle cell disease, Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, systemic infusion reactions, immunoglobulin E (IgE)-mediated hypersensitivity reactions, cytokine release syndrome, immune deficiencies (e.g., primary immunodeficiency, chronic inflammatory demyelinating polyneuropathy), enzyme deficiencies (e.g., Pompe disease, Fabry disease, Gaucher disease), growth factor deficiencies, hormone deficiencies, coagulation disorders (e.g., hemophilia, von Willebrand disease, Factor V Leiden), and cancer.

Exemplary types of drugs that could be included in the delivery devices described herein include, but are not limited to, small molecules, hormones, cytokines, blood products, enzymes, vaccines, anticoagulants, immunosuppressants, antibodies, antibody-drug conjugates, neutralizing antibodies, reversal agents, radioligand therapies, radioisotopes and/or nuclear medicines, diagnostic agents, bispecific antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, 1 protein fragments, nucleotides, protein analogues, protein variants, protein precursors, protein derivatives, chimeric antigen receptor T cell therapies, cell or gene therapies, oncolytic viruses, or immunotherapies.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, immuno-oncology or bio-oncology medications such as immune checkpoints, cytokines, chemokines, clusters of differentiation, interleukins, integrins, growth factors, coagulation factors, enzymes, enzyme inhibitors, retinoids, steroids, signaling proteins, pro-apoptotic proteins, anti- apoptotic proteins, T-cell receptors, B-cell receptors, or costimulatory proteins.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, those exhibiting a proposed mechanism of action, such as human epidermal growth factor receptor 2 (HER-2) receptor modulators, interleukin (IL) modulators, interferon (IFN) modulators, complement modulators, glucagon-like peptide-1 (GLP-1) modulators, glucosedependent insulinotropic polypeptide (GIP) modulators, cluster of differentiation 38 (CD38) modulators, cluster of differentiation 22 (CD22) modulators, Cl esterase modulators, bradykinin modulators, C-C chemokine receptor type 4 (CCR4) modulators, vascular endothelial growth factor (VEGF) modulators, B-cell activating factor (BAFF), P-selectin modulators, neonatal Fc receptor (FcRn) modulators, calcitonin gene-related peptide (CGRP) modulators, epidermal growth factor receptor (EGFR) modulators, cluster of differentiation 79B (CD79B) modulators, tumor-associated calcium signal transducer 2 (Trop-2) modulators, cluster of differentiation 52 (CD52) modulators, B- cell maturation antigen (BCMA) modulators, enzyme modulators, platelet-derived growth factor receptor A (PDGFRA) modulators, cluster of differentiation 319 (CD319 or SLAMF7) modulators, programmed cell death protein 1 and programmed death-ligand 1 (PD-1/PD-L1) inhibitors/modulators, B-lymphocyte antigen cluster of differentiation 19 (CD19) inhibitors, B- lymphocyte antigen cluster of differentiation 20 (CD20) modulators, cluster of differentiation 3 (CD3) modulators, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) modulators, T cell immunoreceptor with Ig and ITIM domains (TIGIT) modulators, V-domain Ig suppressor of T cell activation (VISTA) modulators, indoleamine 2,3-dioxygenase (IDO or INDO) modulators, poliovirus receptor-related immunoglobulin domain-containing protein (PVRIG) modulators, lymphocyte-activation gene 3 (LAG3; also known as cluster of differentiation 223 or CD223) antagonists, cluster of differentiation 276 (CD276 or B7-H3) antigen modulators, cluster of differentiation 47 (CD47) antagonists, cluster of differentiation 30 (CD30) modulators, cluster of differentiation 73 (CD73) modulators, cluster of differentiation 66 (CD66) modulators, cluster of differentiation wl37 (CDwl37) agonists, cluster of differentiation 158 (CD158) modulators, cluster of differentiation 27 (CD27) modulators, cluster of differentiation 58 (CD58) modulators, cluster of differentiation 80 (CD80) modulators, cluster of differentiation 33 (CD33) modulators, cluster of differentiation 159 (CD159 or NKG2) modulators, glucocorticoid- induced TNFR-related (GITR) protein modulators, Killer Ig-like receptor (KIR) modulators, growth arrest-specific protein 6 (GAS6)/AXL pathway modulators, A proliferation-inducing ligand (APRIL) receptor modulators, human leukocyte antigen (HLA) modulators, epidermal growth factor receptor (EGFR) modulators, B-lymphocyte cell adhesion molecule modulators, cluster of differentiation wl23 (CDwl23) modulators, Erbb2 tyrosine kinase receptor modulators, endoglin modulators, mucin modulators, mesothelin modulators, hepatitis A virus cellular receptor 2 (HAVCR2) antagonists, cancer-testis antigen (CTA) modulators, tumor necrosis factor receptor superfamily, member 4 (TNFRSF4 or 0X40) modulators, adenosine receptor modulators, inducible T cell co-stimulator (ICOS) modulators, cluster of differentiation 40 (CD40) modulators, tumor-infiltrating lymphocytes (TIL) therapies, or T-cell receptor (TCR) therapies.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to: etanercept, abatacept, adalimumab, evolocumab, exenatide, secukinumab, erenumab, galcanezumab, fremanezumab-vfrm, alirocumab, methotrexate (amethopterin), tocilizumab, interferon beta-la, interferon beta-lb, peginterferon beta-la, sumatriptan, darbepoetin alfa, belimumab, sarilumab, semaglutide, dupilumab, reslizumab, omalizumab, glucagon, epinephrine, naloxone, insulin, amylin, vedolizumab, eculizumab, ravulizumab, crizanlizumab-tmca, certolizumab pegol, satralizumab, denosumab, romosozumab, benralizumab, emicizumab, tildrakizumab, ocrelizumab, ofatumumab, natalizumab, mepolizumab, risankizumab-rzaa, ixekizumab, and immune globulins.

Exemplary drugs that could be included in the delivery devices described herein may also include, but are not limited to, oncology treatments such as ipilimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, avelumab, cemiplimab, rituximab, trastuzumab, ado-trastuzumab emtansine, fam-trastuzumab deruxtecan-nxki, pertuzumab, transtuzumab-pertuzumab, alemtuzumab, belantamab mafodotin-blmf, bevacizumab, blinatumomab, brentuximab vedotin, cetuximab, daratumumab, elotuzumab, gemtuzumab ozogamicin, 90-Yttrium-ibritumomab tiuxetan, isatuximab, mogamulizumab, moxetumomab pasudotox, obinutuzumab, ofatumumab, olaratumab, panitumumab, polatuzumab vedotin, ramucirumab, sacituzumab govitecan, tafasitamab, or margetuximab.

Exemplary drugs that could be included in the delivery devices described herein include "generic" or biosimilar equivalents of any of the foregoing, and the foregoing molecular names should not be construed as limiting to the "innovator" or "branded" version of each, as in the non-limiting example of innovator medicament adalimumab and biosimilars such as adalimumab-afzb, adalimumab-atto, adalimumab-adbm, and adalimumab-adaz.

Exemplary drugs that could be included in the delivery devices described herein also include, but are not limited to, those used for adjuvant or neoadjuvant chemotherapy, such as an alkylating agent, plant alkaloid, antitumor antibiotic, antimetabolite, or topoisomerase inhibitor, enzyme, retinoid, or corticosteroid. Exemplary chemotherapy drugs include, by way of example but not limitation, 5- fluorouracil, cisplatin, carboplatin, oxaliplatin, doxorubicin, daunorubicin, idarubicin, epirubicin, paclitaxel, docetaxel, cyclophosphamide, ifosfamide, azacitidine, decitabine, bendamustine, bleomycin, bortezomib, busulfan, cabazitaxel, carmustine, cladribine, cytarabine, dacarbazine, etoposide, fludarabine, gemcitabine, irinotecan, leucovorin, melphalan, methotrexate, pemetrexed, mitomycin, mitoxantrone, temsirolimus, topotecan, valrubicin, vincristine, vinblastine, or vinorelbine.

Exemplary drugs that could be included in the delivery devices described herein also include, but are not limited to, analgesics (e.g., acetaminophen), antipyretics, corticosteroids (e.g. hydrocortisone, dexamethasone, or methylprednisolone), antihistamines (e.g., diphenhydramine or famotidine), antiemetics (e.g., ondansetron), antibiotics, antiseptics, anticoagulants, fibrinolytics (e.g., recombinant tissue plasminogen activator [r-TPA] ), antithrombolytics, or diluents such as sterile water for injection (SWFI), 0.9% Normal Saline, 0.45% normal saline, 5% dextrose in water, 5% dextrose in 0.45% normal saline, Lactated Ringer's solution, Heparin Lock Flush solution, 100 U/mL Heparin Lock Flush Solution, or 5000 U/mL Heparin Lock Flush Solution.

Pharmaceutical formulations including, but not limited to, any drug described herein are also contemplated for use in the delivery devices described herein, for example pharmaceutical formulations comprising a drug as listed herein (or a pharmaceutically acceptable salt of the drug) and a pharmaceutically acceptable carrier. Such formulations may include one or more other active ingredients (e.g., as a combination of one or more active drugs), or may be the only active ingredient present, and may also include separately administered or co-formulated dispersion enhancers (e.g. an animal-derived, human-derived, or recombinant hyaluronidase enzyme), concentration modifiers or enhancers, stabilizers, buffers, or other excipients.

Exemplary drugs that could be included in the delivery devices described herein include, but are not limited to, a multi-medication treatment regimen such as AC, Dose-Dense AC, TCH, GT, EC, TAC, TC, TCHP, CMF, FOLFOX, mFOLFOX6, mFOLFOX7, FOLFCIS, CapeOx, FLOT, DCF, FOLFIRI, FOLFIRINOX, FOLFOXIRI, IROX, CHOP, R-CHOP, RCHOP-21, Mini-CHOP, Maxi-CHOP, VR-CAP, Dose-Dense CHOP, EPOCH, Dose-Adjusted EPOCH, R-EPOCH, CODOX-M, IVAC, HyperCVAD, R-HyperCVAD, SC-EPOCH-RR, DHAP, ESHAP, GDP, ICE, MINE, CEPP, CDOP, GemOx, CEOP, CEPP, CHOEP, CHP, GCVP, DHAX, CALGB 8811, HIDAC, MOpAD, 7 + 3, 5 +2, 7 + 4, MEC, CVP, RBAC500, DHA-Cis, DHA-Ca, DHA-Ox, RCVP, RCEPP, RCEOP, CMV, DDMVAC, GemFLP, ITP, VIDE, VDC, VAI, VDC-IE, MAP, PCV, FCR, FR, PCR, HDMP, OFAR, EMA/CO, EMA/EP, EP/EMA, TP/TE, BEP, TIP, VIP, TPEx, ABVD, BEACOPP, AVD, Mini- BEAM, IGEV, C-MOPP, GCD, GEMOX, CAV, DT-PACE, VTD-PACE, DCEP, ATG, VAC, VelP, OFF, GTX, CAV, AD, MAID, AIM, VAC-IE, ADOC, or PE.

Embodiments of the disclosure are additionally set out in the following clauses:

1. A drive assembly (102) for a medicament delivery device (100), the drive assembly (102) extending along a longitudinal axis (A) between a proximal end (110) that in use is located towards a site at which a medicament is delivered to a user by the medicament delivery device (100) and a distal end (108), and the drive assembly (102) comprising: a drive member (202); a plunger rod (200) arranged for movement in a proximal direction to urge a piston (220) of a medicament container (120) to expel the medicament from the medicament container (120), the plunger rod (200) having tabs (406) that extend radially at two or more axial positions, which axial positions are spaced from one another along the length of the plunger rod (200); a rotator (204) arranged to transfer force from the drive member (202) to the plunger rod (200) to cause the plunger rod (200) to move in the proximal direction, the rotator (204) having a first rotational orientation, a second rotational orientation and axial positions, in which axial positions it is prevented from movement in the proximal direction when in the first rotational orientation and released for the movement in the proximal direction when in the second rotational orientation; an actuator (206) arranged for movement in a distal direction to cause the rotator (204) to rotate from the first rotational orientation to the second rotational orientation when in the axial positions; and a resetting arrangement for causing the rotator (204) to rotate from the second rotational orientation to the first rotational orientation as the rotator (204) moves in the proximal direction between the axial positions, wherein the rotator (204) is arranged to transfer the force from the drive member (202) to the plunger rod (200) by having a proximally facing surface (608) that cooperates with at least one of the tabs (406) of the plunger rod (200) to urge the plunger rod (200) for the movement in the proximal direction as the rotator (204) moves in the proximal direction between the axial positions, and wherein the rotator (204) has a gap (610) in the proximally facing surface (608) that allows the plunger rod (200) to move in the distal direction by the tabs (406) passing through the gap (610) when the rotator (204) is in first rotational orientation.

2. The drive assembly (102) of clause 1, wherein the tabs (406) comprise groups of tabs, the tabs (406) of each respective group of tabs being located at the same axial position along the length of the plunger rod (200) but at different locations around the circumference of the plunger rod (200).

3. The drive assembly (102) of clause 2, wherein the tabs (406) of each respective group of tabs are spaced equally around the circumference of the plunger rod (200).

4. The drive assembly (102) of clause 2 or clause 3, wherein each group of tabs comprises two tabs (406) offset from one another by 180° around the circumference of the plunger rod (200).

5. The drive assembly (102) of any one of the preceding clauses, wherein the rotator (204) has a retainer (602) with a distally facing surface (616) arranged to cooperate with the one or more of the tabs (406) when the rotator (204) is in the first rotational orientation to prevent the plunger rod (200) from moving in the proximal direction.

6. The drive assembly (102) of clause 5, wherein the distally facing surface (616) of the retainer (602) is provided by a protrusion (606) extending radially inwards.

7. The drive assembly (102) of any one of the preceding clauses, having a return mechanism comprising: a traveler (210) biased to move in the distal direction; and a retaining element (806) having a first position in which it prevents the traveler (210) from moving in the distal direction and a second position in which it releases the traveler (210) to move in the distal direction, wherein the plunger rod (200) has a return protrusion {416} that cooperates with the retaining element (806) after the movement of the plunger rod (200) in the proximal direction to cause the retaining element (806) to move from the first position to the second position to release the traveler (210) to move in the distal direction and a distally facing surface (904) with which the traveler (210) cooperates to urge the plunger rod (200) in the distal direction as the traveler (210) moves in the distal direction. 8. The drive assembly (102) of clause 7 , comprising a biasing element (208), wherein the traveler (210) is biased to move in the distal direction by being urged in the distal direction by the biasing element (208).

9. The drive assembly (102) of clause 8, wherein the biasing element (208) also biases the actuator (206) in the proximal direction.

10. The drive assembly (102) of clause 8 or clause 9, wherein the biasing element (208) is a compression spring.

11. The drive assembly (102) of any one of clauses 7 to 10, wherein the traveler (210) is generally ring-shaped.

12. The drive assembly (102) of any one of clauses 7 to 11, wherein the retaining element (806) comprises a proximally facing surface (808).

13. The drive assembly (102) of clause 12, comprising a housing (106), wherein the proximally facing surface (808) is provided by a protrusion extending radially inwards from the housing (106).

14. The drive assembly (102) of any one of the preceding clauses, comprising a retaining arrangement between the rotator (204) and a/the housing (106), the retaining arrangement comprising a protrusion (614) arranged to ride against a circumferentially extending surface (802) to retain the rotator (204) at one of the axial positions.

15. The drive assembly (102) of clause 14, wherein the protrusion (614) of the retaining arrangement is provided on the rotator (204) and the circumferentially extending surface (802) is provided on the housing (106).

16. The drive assembly (102) of clause 15, wherein the housing (106) has at least one additional circumferentially extending surface (802), one of the circumferentially extending surface (802) and the additional circumferentially extending surface(s) (802) corresponding to each of the axial positions of the rotator (204) respectively, and the protrusion (614) being arranged to ride against a respective one of the circumferentially extending surface (802) and the additional circumferentially extending surface(s) (802) corresponding the axial position that the rotator (204) is in whilst the medicament delivery device (100) is in a given configuration.

17. The drive assembly (102) of any one of the preceding clauses, comprising a/the housing (106) and a resetting arrangement between the housing (106) and the rotator (204), the resetting arrangement comprising a protrusion (614) arranged to ride against a ramp (804) such that movement of the rotator (204) axially in the proximal direction between two of the axial positions forces the protrusion (614) along the ramp (804) such that the rotator (204) rotates from the second rotational orientation towards the first rotational orientation.

18. The drive assembly (102) of clause 17, wherein the protrusion (614) of the resetting arrangement is provided on the rotator (204) and the ramp (804) is provided on the housing (104).

19. The drive assembly (102) of clause 14 and clause 17, wherein the protrusion (614) of the retaining arrangement is the same element as the protrusion (614) of the resetting arrangement.

20. The drive assembly (102) of any one of clauses 17 to 19, wherein the resetting arrangement further comprising an additional ramp (613) on the rotator against which a protrusion (704) of the actuator (206) rides to urge the rotator (204) towards the first rotational orientation as the actuator (206) moves axially in the proximal direction.

21. The drive assembly (102) of any one of the preceding clauses, comprising an actuating arrangement between the actuator (206) and the rotator (204), the actuating arrangement comprising a/the protrusion (704) of the actuator (206) riding against a ramp (612) such that the movement of the actuator (206) in the distal direction forces the protrusion (704) along the ramp (612) such that the rotator (204) rotates from the first rotational orientation to the second rotational orientation to release the rotator (204) and the plunger rod (200) for the movement in the proximal direction.

22. A medicament delivery device (100) comprising the drive assembly (102) of any one of the preceding clauses.

23. The medicament delivery device (100) of clause 22, comprising a removeable cassette (104), the removeable cassette (104) comprising: a medicament container carrier (116) for accommodating a medicament container (120) having a delivery member (1300); and a delivery member cover (118) having a first position in which it covers the delivery member (1300) and a second position in which it exposes the delivery member (1300) for delivery of a medicament from the medicament container (120), wherein the removeable cassette (104) is releasably secured to the drive assembly (104) by the delivery member cover (118) engaging with the actuator (206).

24. A medicament delivery device (100) comprising a drive assembly (102) and a removeable cassette (104), the drive assembly (102) comprising: a drive member (202); a plunger rod (200) arranged for movement in a proximal direction to urge a piston (220) of a medicament container (120) to expel a medicament from the medicament container (120); and an actuator (206) moveable in a distal direction to cause the plunger rod (200) to be released for the movement in the proximal direction, and the removeable cassette (104) comprising: a medicament container carrier (116) for accommodating the medicament container (120) having a delivery member (1300); and a delivery member cover (118) having a first position in which it covers the delivery member (1300) and a second position in which it exposes the delivery member (1300) for delivery of a medicament from the medicament container (120), wherein the removeable cassette (104) is releasably secured to the drive assembly (102) by the delivery member cover (118) engaging with the actuator (206).

25. The medicament delivery device (100) of clause 23 or clause 24, wherein the removable cassette (104) and the drive assembly (102) have a first rotational orientation in which the delivery member cover (118) cooperates with the actuator (206) to secure the removeable cassette (104) to the drive assembly (102) and a second rotational orientation in which the delivery member cover (118) and the actuator (206) are separable from one another to release the removeable cassette (104) from the drive assembly (102).

26. The medicament delivery device (100) of any one of clauses 23 to 25, wherein the removeable cassette (104) is releasably secured to the drive assembly (102) by the delivery member cover (118) engaging with a proximal end of the actuator (206).

27. The medicament delivery device (100) of any one of clauses 23 to 26, wherein one of the delivery member cover (118) and the actuator (206) has a protrusion (300) and the other of the delivery member cover (118) and the actuator (206) has a recess (302), the protrusion (300) and the recess (302) cooperating to secure the removeable cassette (104) to the drive assembly (102).

28. The medicament delivery device (100) of clause 27, wherein the protrusion (300) is provided on the delivery member cover (118) and the recess (302) is provided on the actuator (206). 29. The medicament delivery device (100) of clause 27 or clause 28, wherein the protrusion (300) is in the form of a circumferentially extending ridge and the recess (302) is in the form of a circumferentially extending slot.

Claims

2. The drive assembly (102) of claim 1, wherein the tabs (406) comprise groups of tabs, the tabs (406) of each respective group of tabs being located at the same axial position along the length of the plunger rod (200) but at different locations around the circumference of the plunger rod (200), preferably wherein the tabs (406) of each respective group of tabs are spaced equally around the circumference of the plunger rod (200) and/or preferably wherein each group of tabs comprises two tabs (406) offset from one another by 180° around the circumference of the plunger rod (200).

3. The drive assembly (102) of any one of the preceding claims, wherein the rotator (204) has a retainer (602) with a distally facing surface (616) arranged to cooperate with the one or more of the tabs (406) when the rotator (204) is in the first rotational orientation to prevent the plunger rod (200) from moving in the proximal direction, preferably wherein the distally facing surface (616) of the retainer (602) is provided by a protrusion (606) extending radially inwards.

4. The drive assembly (102) of any one of the preceding claims, having a return mechanism comprising: a traveler (210) biased to move in the distal direction; and a retaining element (806) having a first position in which it prevents the traveler (210) from moving in the distal direction and a second position in which it releases the traveler (210) to move in the distal direction, wherein the plunger rod (200) has a return protrusion {416} that cooperates with the retaining element (806) after the movement of the plunger rod (200) in the proximal direction to cause the retaining element (806) to move from the first position to the second position to release the traveler (210) to move in the distal direction and a distally facing surface (904) with which the traveler (210) cooperates to urge the plunger rod (200) in the distal direction as the traveler (210) moves in the distal direction, preferably comprising a biasing element (208), wherein the traveler (210) is biased to move in the distal direction by being urged in the distal direction by the biasing element (208), preferably wherein the biasing element (208) also biases the actuator (206) in the proximal direction, preferably wherein the biasing element (208) is a compression spring, and/or preferably wherein the traveler (210) is generally ring-shaped and/or the retaining element (806) comprises a proximally facing surface (808) and preferably comprising a housing (106) wherein the proximally facing surface (808) is provided by a protrusion extending radially inwards from the housing (106).

5. The drive assembly (102) of any one of the preceding claims, comprising a retaining arrangement between the rotator (204) and a/the housing (106), the retaining arrangement comprising a protrusion (614) arranged to ride against a circumferentially extending surface (802) to retain the rotator (204) at one of the axial positions, preferably wherein the protrusion (614) of the retaining arrangement is provided on the rotator (204) and the circumferentially extending surface (802) is provided on the housing (106), and preferably wherein the housing (106) has at least one additional circumferentially extending surface (802), one of the circumferentially extending surface (802) and the additional circumferentially extending surface(s) (802) corresponding to each of the axial positions of the rotator (204) respectively, and the protrusion (614) being arranged to ride against a respective one of the circumferentially extending surface (802) and the additional circumferentially extending surface(s) (802) corresponding the axial position that the rotator (204) is in whilst the medicament delivery device (100) is in a given configuration.

6. The drive assembly (102) of any one of the preceding claims, comprising a/the housing (106) and a resetting arrangement between the housing (106) and the rotator (204), the resetting arrangement comprising a protrusion (614) arranged to ride against a ramp (804) such that movement of the rotator (204) axially in the proximal direction between two of the axial positions forces the protrusion (614) along the ramp (804) such that the rotator (204) rotates from the second rotational orientation towards the first rotational orientation, preferably wherein the protrusion (614) of the resetting arrangement is provided on the rotator (204) and the ramp (804) is provided on the housing (104), preferably wherein the protrusion (614) of the retaining arrangement is the same element as the protrusion (614) of the resetting arrangement and preferably wherein the resetting arrangement further comprising an additional ramp (613) on the rotator against which a protrusion (704) of the actuator (206) rides to urge the rotator (204) towards the first rotational orientation as the actuator (206) moves axially in the proximal direction.

7. The drive assembly (102) of any one of the preceding claims, comprising an actuating arrangement between the actuator (206) and the rotator (204), the actuating arrangement comprising a/the protrusion (704) of the actuator (206) riding against a ramp (612) such that the movement of the actuator (206) in the distal direction forces the protrusion (704) along the ramp (612) such that the rotator (204) rotates from the first rotational orientation to the second rotational orientation to release the rotator (204) and the plunger rod (200) for the movement in the proximal direction.

8. A medicament delivery device (100) comprising the drive assembly (102) of any one of the preceding claims.

9. The medicament delivery device (100) of claim 8, comprising a removeable cassette (104), the removeable cassette (104) comprising: a medicament container carrier (116) for accommodating a medicament container (120) having a delivery member (1300); and a delivery member cover (118) having a first position in which it covers the delivery member (1300) and a second position in which it exposes the delivery member (1300) for delivery of a medicament from the medicament container (120), wherein the removeable cassette (104) is releasably secured to the drive assembly (104) by the delivery member cover (118) engaging with the actuator (206).

10. A medicament delivery device (100) comprising a drive assembly (102) and a removeable cassette (104), the drive assembly (102) comprising: a drive member (202); a plunger rod (200) arranged for movement in a proximal direction to urge a piston (220) of a medicament container (120) to expel a medicament from the medicament container (120); and an actuator (206) moveable in a distal direction to cause the plunger rod (200) to be released for the movement in the proximal direction, and the removeable cassette (104) comprising: a medicament container carrier (116) for accommodating the medicament container (120) having a delivery member (1300); and a delivery member cover (118) having a first position in which it covers the delivery member (1300) and a second position in which it exposes the delivery member (1300) for delivery of a medicament from the medicament container (120), wherein the removeable cassette (104) is releasably secured to the drive assembly (102) by the delivery member cover (118) engaging with the actuator (206).

11. The medicament delivery device (100) of claim 9 or claim 10, wherein the removable cassette (104) and the drive assembly (102) have a first rotational orientation in which the delivery member cover (118) cooperates with the actuator (206) to secure the removeable cassette (104) to the drive assembly (102) and a second rotational orientation in which the delivery member cover (118) and the actuator (206) are separable from one another to release the removeable cassette (104) from the drive assembly (102).

12. The medicament delivery device (100) of any one of claims 9 to 11, wherein the removeable cassette (104) is releasably secured to the drive assembly (102) by the delivery member cover (118) engaging with a proximal end of the actuator (206).

13. The medicament delivery device (100) of any one of claims 9 to 12, wherein one of the delivery member cover (118) and the actuator (206) has a protrusion (300) and the other of the delivery member cover (118) and the actuator (206) has a recess (302), the protrusion (300) and the recess (302) cooperating to secure the removeable cassette (104) to the drive assembly (102).

14. The medicament delivery device (100) of claim 13, wherein the protrusion (300) is provided on the delivery member cover (118) and the recess (302) is provided on the actuator (206).

15. The medicament delivery device (100) of claim 13 or claim 14, wherein the protrusion (300) is in the form of a circumferentially extending ridge and the recess (302) is in the form of a circumferentially extending slot.