Patent Description:
Injection devices, for example auto-injectors, typically have a sealed container of medicament, and a needle for injection of the medicament into a patient. During injection, a drive mechanism displaces a plunger into the medicament container to dispense medicament through the needle. Normally, a coil spring provides the motive force to displace the plunger. As the coil spring extends, the force exerted by the spring on the plunger decays in accordance with Hook's law. Initially, the spring force is high and dispenses medicament at a high rate. For some patients, this high rate of medicament delivery can be uncomfortable.

An example injector device is taught by <CIT>, which discloses an assembly for a drug delivery device and a drug delivery device.

According to the present invention, there is provided an injector device comprising:.

Therefore a user can pre-set an injection speed according to the patient's preference. The injection speed is easily adjusted.

The displacing member may comprise a spring.

Therefore, the rate of medicament delivery can be slowed for patients who find a relatively higher rate of medicament delivery uncomfortable, particularly at the start of injection where the spring force is high.

A region of the outer surface of the plunger may be covered with a high friction material, said region being arranged to contact the braking surface of the brake during movement of the plunger between an initial position and an end stop position.

The proportion of the outer surface of the plunger covered by the high friction material may increase toward the distal end of the plunger.

The coefficient of friction of the high friction material may change from a relatively lower coefficient of friction to a relatively higher coefficient of friction toward the distal end of the plunger.

Therefore the friction force between the outer surface of the plunger the braking surface declines as the plunger is displaced, compensating for the decay in the spring force and causing a substantially constant rate of injection.

A region of the outer surface of the plunger may be provided with a channel, said region being arranged to contact the braking surface of the brake during movement of the plunger between an initial position and an end stop position.

The width and/or depth of the channel may decrease towards the distal end of the plunger.

Therefore the contact pressure between the brake and the plunger is reduced as the plunger is displaced to compensate for the decay in the spring force.

An inner surface of the collar may contact an outer surface of the brake.

Therefore the brake force adjustment mechanism is easily constructed.

The outer surface of the brake may comprise a gradient so that the thickness of the brake increases in a circumferential direction of the device, so that, when the collar is rotated, the contact pressure between the braking surface and the outer surface of the plunger rod varies in dependence on the direction of rotation of the collar.

The inner surface of the collar may comprise a gradient so that the thickness of an inner portion of the collar increases in a circumferential direction of the device, so that, when the collar is rotated, the contact pressure between the braking surface and the outer surface of the plunger rod varies in dependence on the direction of rotation of the collar.

An inner surface of the sleeve may contact an outer surface of the brake.

The outer surface of the brake may comprise a gradient so that the thickness of the brake increases in a longitudinal direction of the device, so that, the contact pressure between the braking surface and the outer surface of the plunger rod varies in dependence on the direction that the sleeve slides along the longitudinal axis.

The inner surface of the sleeve may comprise a gradient so that the thickness of an inner portion of the sleeve increases in a longitudinal direction of the device, so that, the contact pressure between the braking surface and the outer surface of the plunger rod varies in dependence on the direction that the sleeve slides along the longitudinal axis.

The plunger rod may be tapered so that the diameter of the distal end of the plunger rod is greater than the diameter of a proximal end of the plunger rod.

A drug delivery device, as described herein, may be configured to inject a medicament into a patient. For example, delivery could be sub-cutaneous, intra-muscular, or intravenous. Such a device could be operated by a patient or care-giver, such as a nurse or physician, and can include various types of safety syringe, pen-injector, or auto-injector. The device can include a cartridge-based system that requires piercing a sealed ampule before use. Volumes of medicament delivered with these various devices can range from about <NUM> to about <NUM>. Another device can include a large volume device ("LVD") or patch pump, configured to adhere to a patient's skin for a period of time (e.g., about <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes) to deliver a "large" volume of medicament (typically about <NUM> to about <NUM>). Yet another device may comprise a pre-filled syringe within a housing of the device. The syringe may be fixed within the housing or may be moveable within the housing, for example from a retracted position to an operation extended position.

For example, the device may be customized to inject a medicament within a certain time period (e.g., about <NUM> to about <NUM> seconds for auto-injectors). Other specifications can include a low or minimal level of discomfort, or to certain conditions related to human factors, shelf-life, expiry, biocompatibility, environmental considerations, etc. Such variations can arise due to various factors, such as, for example, a drug ranging in viscosity from about <NUM> mPa·s to about <NUM> mPa·s (from about <NUM> cP to about <NUM> cP).

The delivery devices described herein can also include one or more automated functions. For example, one or more of combining the needle and cartridge, needle insertion, medicament injection, and needle retraction can be automated. Energy for one or more automation steps can be provided by one or more energy sources. Energy sources can include, for example, mechanical, pneumatic, chemical, or electrical energy. For example, mechanical energy sources can include springs, levers, elastomers, or other mechanical mechanisms to store or release energy. One or more energy sources can be combined into a single device. Devices can further include gears, valves, or other mechanisms to convert energy into movement of one or more components of a device.

The one or more automated functions of an auto-injector may each be activated via an activation mechanism. Such an activation mechanism can include an actuator, for example, one or more of a button, a lever, a needle sleeve, or other activation component. Activation of an automated function may be a one-step or multi-step process. That is, a user may need to activate one or more activation components in order to cause the automated function. For example, in a one-step process, a user may depress a needle sleeve against their body in order to cause injection of a medicament. Other devices may require a multi-step activation of an automated function. For example, a user may be required to depress a button and retract a needle shield in order to cause injection.

For example, activation of a first automated function may activate at least two of combining the needle and cartridge, needle insertion, medicament injection, and needle retraction.

According to some embodiments of the present disclosure, an exemplary drug delivery device <NUM> is shown in <FIG>. Device <NUM>, as described above, is configured to inject a medicament into a patient's body. Device <NUM> includes a housing <NUM> which contains a medicament container <NUM> that defines a reservoir containing the medicament to be injected, and the components required to facilitate one or more steps of the delivery process. The medicament container <NUM> may be a cartridge or pre-filled syringe.

The device <NUM> can also include a cap <NUM> that can be detachably mounted to the housing <NUM>. Typically, a user must remove cap <NUM> from housing <NUM> before device <NUM> can be operated.

As shown, housing <NUM> is substantially cylindrical and has a substantially constant diameter along the longitudinal axis A-A. The housing <NUM> has a distal region D and a proximal region P. The term "distal" refers to a location that is relatively closer to a site of injection, and the term "proximal" refers to a location that is relatively further away from the injection site.

Device <NUM> can also include a needle sleeve <NUM> coupled to housing <NUM> to permit movement of sleeve <NUM> relative to housing <NUM>. For example, sleeve <NUM> can move in a longitudinal direction parallel to longitudinal axis A-A. Specifically, movement of sleeve <NUM> in a proximal direction can permit a needle <NUM> to extend from distal region D of housing <NUM>.

Insertion of needle <NUM> can occur via several mechanisms. For example, needle <NUM> may be fixedly located relative to housing <NUM> and initially be located within an extended needle sleeve <NUM>. Proximal movement of sleeve <NUM> by placing a distal end of sleeve <NUM> against a patient's body and moving housing <NUM> in a distal direction will uncover the distal end of needle <NUM>. Such relative movement allows the distal end of needle <NUM> to extend into the patient's body. Such insertion is termed "manual" insertion as needle <NUM> is manually inserted via the patient's manual movement of housing <NUM> relative to sleeve <NUM>.

Another form of insertion is "automated", whereby needle <NUM> moves relative to housing <NUM>. Such insertion can be triggered by movement of sleeve <NUM> or by another form of activation, such as, for example, a button <NUM>. As shown in <FIG>, button <NUM> is located at a proximal end of housing <NUM>. However, in other embodiments, button <NUM> could be located on a side of housing <NUM>.

Other manual or automated features can include drug injection or needle retraction, or both. Injection is the process by which a bung or piston <NUM> is moved from a proximal location to a more distal location within the reservoir of the cartridge <NUM> in order to force a medicament from the cartridge <NUM> through needle <NUM>. In some embodiments, a drive mechanism <NUM> is activated to force medicament from the cartridge <NUM>. The drive mechanism <NUM> comprises a drive spring <NUM>. The drive spring <NUM> is under compression before drive mechanism <NUM> is activated. A proximal end of the drive spring <NUM> can be fixed within proximal region P of housing <NUM>, and a distal end of the drive spring <NUM> can be configured to apply a compressive force to a proximal surface of piston <NUM>. Following activation, at least part of the energy stored in the drive spring <NUM> can be applied to the proximal surface of piston <NUM>. This compressive force can act on piston <NUM> to move it in a distal direction. Such distal movement acts to compress the liquid medicament within the cartridge <NUM>, forcing it out of needle <NUM>.

Following injection, needle <NUM> can be retracted within sleeve <NUM> or housing <NUM>. Retraction can occur when sleeve <NUM> moves distally as a user removes device <NUM> from a patient's body. This can occur as needle <NUM> remains fixedly located relative to housing <NUM>. Once a distal end of sleeve <NUM> has moved past a distal end of needle <NUM>, and needle <NUM> is covered, sleeve <NUM> can be locked. Such locking can include locking any proximal movement of sleeve <NUM> relative to housing <NUM>.

Another form of needle retraction can occur if needle <NUM> is moved relative to housing <NUM>. Such movement can occur if the cartridge <NUM> within housing <NUM> is moved in a proximal direction relative to housing <NUM>. This proximal movement can be achieved by using a retraction spring (not shown), located in distal region D. A compressed retraction spring, when activated, can supply sufficient force to the cartridge <NUM> to move it in a proximal direction. Following sufficient retraction, any relative movement between needle <NUM> and housing <NUM> can be locked with a locking mechanism. In addition, button <NUM> or other components of device <NUM> can be locked as required.

<FIG> shows an injector device <NUM> of one embodiment of the invention.

The injector device <NUM> comprises an elongate outer housing <NUM> having a proximal region P and a distal region D. The distal region D is relatively closer to an injection site, and the proximal region P is relatively further away from the injection site. In the present embodiment, the housing <NUM> has a curved outer surface for more comfortable handling. Preferably, the housing <NUM> is cylindrical.

A medicament container <NUM> is supported within the outer housing <NUM> so that the medicament container <NUM> is held in fixed relation relative to the housing <NUM>. A proximal end of the medicament container <NUM> is sealed by a piston <NUM> which is displaced into the medicament container <NUM> in use to dispense medicament from the medicament container <NUM>. A needle <NUM> is provided in fluid communication with a distal end of the medicament container <NUM>. The needle <NUM> extends beyond a distal end of the housing <NUM> so that, when the distal end of the housing <NUM> is pressed up against an injection site, the needle <NUM> penetrates the injection site for subcutaneous delivery of the medicament.

A drive mechanism <NUM> is provided within the proximal region P of the housing <NUM>. In use, the drive mechanism <NUM> is configured to displace the piston <NUM> into the medicament container <NUM>. The drive mechanism <NUM> comprises a displacing member <NUM> (hereinafter a drive spring <NUM>), a plunger <NUM> and a release mechanism <NUM>. Prior to use, the plunger <NUM> is held in an initial position against the force of the spring <NUM> by the release mechanism <NUM>.

A dose delivery button <NUM> is provided in a proximal end of the housing <NUM> and is mechanically coupled to the release mechanism <NUM>. During use, the dose delivery button <NUM> is manipulated by a user to cause the release mechanism <NUM> to release the plunger <NUM>. The spring <NUM> then forces the plunger <NUM> in a distal direction of the device <NUM>. A distal end of the plunger <NUM> abuts the piston <NUM> so that the piston <NUM> is displaced with the plunger <NUM> to dispense medicament from the medicament container <NUM>.

The plunger <NUM> comprises an elongate tube <NUM> with a closed distal end <NUM>. The spring <NUM> is a coil spring and is disposed within the plunger <NUM>. A distal end of the spring <NUM> abuts the closed end <NUM> of the plunger <NUM>, while a proximal end of the spring <NUM> abuts an inner surface of the device <NUM>. In the illustrated embodiment, the inner surface is an inner surface <NUM> of the dose delivery button <NUM>.

The release mechanism <NUM> comprises arms <NUM> that extend from the inner surface <NUM> of the dose delivery button <NUM>. Catches <NUM> are provided at the distal end of each arm <NUM>. The catches <NUM> are configured to cooperate with a respective aperture <NUM> in the tubular wall <NUM> of the plunger <NUM> to hold the plunger <NUM> against the force of the spring <NUM>. The catches <NUM> may be removed from the apertures <NUM> by manipulation of the dose delivery button <NUM>. For example, the dose delivery button <NUM> may be rotated to move the arms <NUM> in a circular fashion about a longitudinal axis A-A of the device <NUM>. In this way, the catches <NUM> are removed from the apertures <NUM> and the plunger <NUM> is then free for displacement under the force of the spring <NUM>.

A spring support <NUM> extends from the inner surface <NUM> of the dose delivery button <NUM> and through the centre of the spring <NUM>. The spring support <NUM> is configured to support the spring <NUM> as the plunger <NUM> is displaced. When the plunger <NUM> is in the initial position, the spring <NUM> is disposed almost entirely within the plunger <NUM>. However, during displacement of the plunger <NUM> the spring <NUM> extends from the proximal end of the plunger <NUM> and out of the supporting confines of the plunger's tubular wall <NUM>. The spring support <NUM> ensures that the spring <NUM> remains axially aligned with the device as it uncoils.

A needle sleeve <NUM> is provided in a distal end of the housing <NUM>. The needle sleeve <NUM> extends from the distal end of the housing <NUM> to conceal the needle <NUM> when the needle sleeve <NUM> is an initial position. The needle sleeve <NUM> is displaceable into the housing <NUM> in telescopic fashion to expose the needle <NUM>. The needle sleeve <NUM> is biased into the initial position by a sleeve spring <NUM>. Therefore, a user may press the distal end of the device <NUM> up against an injection site to displace the needle sleeve <NUM> into the housing <NUM> and to cause the needle <NUM> to penetrate the injection site.

A cap <NUM> and needle shield <NUM> are provided for additional security. The cap <NUM> locates over the needle sleeve <NUM> and must be removed with the needle shield <NUM> prior to use.

During displacement of the plunger <NUM>, the force exerted by the spring <NUM> on the plunger <NUM> decays linearly as the spring <NUM> extends. This will be apparent to any skilled person and can be derived from Hook's law. It shall be appreciated that this effect is not limited to mechanical coil springs and extends to other types of displacing members <NUM>, such as compressed gas actuators and other types of pneumatic or mechanical springs. The illustrated embodiments comprise coil springs <NUM> by way of example only.

The drop in force due to spring extension causes a corresponding change in the rate at which medicament is dispensed from the medicament container <NUM>: as the spring force decays, so too does the rate at which medicament is dispensed.

Furthermore, the rate of injection can vary depending on the viscosity of the medicament being injected. Medicaments range in viscosity from about <NUM> mPa·s to about <NUM> mPa·s (from about <NUM> cP to about <NUM> cP) and this range will have a corresponding effect on the rate at which medicament is dispensed for a given spring force. Temperature may also affect the viscosity of the medicament and, therefore, the rate at which the medicament is dispensed.

The present invention aims to afford the user of the device <NUM> more control over the rate at which medicament is dispensed and to compensate for the spring force decay and/or variations in the viscosity of the medicament.

It has been determined that pain perception during an injection varies among patients. In some patients, a quick injection is perceived as less painful, whereas in other patients a slow injection is perceived as less painful. Having an inconsistent rate of delivery because of the decaying spring force is likely to cause some discomfort at some stage during injection in a majority of patients.

Therefore, the present invention provides a brake <NUM> to slow the rate of progress of the plunger <NUM> as it is displaced by the spring <NUM>. The brake <NUM> comprises a material that is held against the plunger <NUM> so that the plunger is slowed by friction.

In a first embodiment illustrated in <FIG>, the brake <NUM> comprises a cylindrical body <NUM> having an inside surface <NUM> in contact with an outer surface <NUM> of the tubular wall <NUM> of the plunger <NUM>. The body <NUM> may be attached to an inner surface of the housing <NUM> or, as illustrated, the body <NUM> may abut a proximal end of the medicament container <NUM> so that the body <NUM> is held in fixed relation relative to the housing <NUM> during displacement of the plunger <NUM>. Therefore, as the plunger <NUM> is displaced, the outer surface <NUM> of the plunger <NUM> slides across the inside surface <NUM> of the body <NUM> so that movement of the plunger <NUM> is resisted by friction between the two surfaces <NUM>, <NUM>.

In one embodiment, as illustrated in <FIG> (in which the plunger <NUM> is shown in isolation), a region <NUM> of the outer surface <NUM> of the plunger <NUM> is covered with a high friction material. The high friction material causes more friction with the brake <NUM> than the remaining outer surface of the plunger <NUM>.

The proportion of the outer surface <NUM> covered by the region of high friction material increases toward the distal end D of the plunger <NUM>. For example, in the illustrated embodiment, opposing edges <NUM> of the region <NUM> of high friction material extending longitudinally along the length of the plunger <NUM> are oblique, so that the width of said region <NUM> increases toward the distal end D of the plunger <NUM>. Therefore, the friction between the brake <NUM> and the plunger <NUM> is reduced as the plunger <NUM> is displaced. This compensates for the decay in the spring force, so that, as the plunger <NUM> is displaced by the spring <NUM>, the region <NUM> of high friction material causes the plunger <NUM> to move at a constant speed through its full range of movement between the initial position and an end stop position.

In another embodiment illustrated by <FIG> - in which like features retain the same reference numbers - the device further comprises a brake force adjustment mechanism <NUM>. The brake force adjustment mechanism <NUM> is configured to allow a user to change the speed at which the plunger <NUM> is displaced, hereinafter referred to as the injection speed. The brake force adjustment mechanism <NUM> is operable to adjust the force between the brake <NUM> and the plunger <NUM>, hereinafter referred to as the brake force. Therefore, if a patient would prefer a slower injection, the brake force adjustment mechanism <NUM> can be used to reduce the injection speed and vice versa. The brake force adjustment mechanism <NUM> therefore allows the user to control the injection speed in accordance with their preferences. The brake force adjustment <NUM> mechanism can also be used to compensate for the particular viscosity of the medicament to be injected. For instance, a medicament having a first viscosity would be injected at a first injection speed, while a medicament having a second viscosity, where the second viscosity is higher than the first viscosity, would be injected at a second injection speed, where the second injection speed is slower than the first injection speed. Therefore, if the device is provided with a medicament having a relatively lower viscosity, the user may adjust the brake force adjustment mechanism <NUM> to increase the brake force and maintain the injection speed as close as possible to their preferred injection speed. Likewise, if the device is provided with a medicament having a relatively higher viscosity, the user may adjust the brake force adjustment mechanism <NUM> to reduce the brake force and maintain the injection speed as close as possible to their preferred injection speed. In one embodiment the user is provided with information about the viscosity of the medicament and corresponding settings for the brake force adjustment mechanism <NUM> to allow the user to select from a range of predetermined injection speeds.

In the embodiment illustrated by <FIG>, the brake force adjustment mechanism <NUM> comprises a collar <NUM> which is supported in the proximal region of the housing <NUM> overlapping the plunger <NUM>. The collar <NUM> is rotatably supported so that a user may rotate the collar <NUM> about the longitudinal axis A-A of the device <NUM>. Rotation of the collar <NUM> in one direction increases the injection speed, while rotation in the other reduces the injection speed, as will be explained further below.

The collar <NUM> comprises an outer surface <NUM>, which a user can grip to rotate the collar <NUM> about the longitudinal axis A-A of the device <NUM>; and an inner surface <NUM>, which is configured to interact with the brake <NUM>. Rotation of the collar <NUM> in one direction presses the brake <NUM> against the plunger <NUM> with greater force.

The collar <NUM> may be rotated between a first position - representative of a fastest injection speed - and a second position - representative of a slowest injection speed.

In the first position, the brake <NUM> is pressed against the plunger <NUM> with the lowest force. In the second position, the brake <NUM> is pressed against the plunger <NUM> with the greatest force. Rotation of the collar <NUM> between the first and second positions varies the force with which the brake <NUM> is pressed against the plunger <NUM>. Rotation of the collar <NUM> toward the second position increases the force with which the brake <NUM> is pressed against the plunger <NUM>. Therefore, the collar <NUM> can be rotated to fine tune the injection speed to the patient's preference.

In this embodiment, the brake <NUM> is integrally formed with the housing <NUM> and comprises at least one arm <NUM> which extends from the inner surface of the housing <NUM>. In <FIG>, two arms <NUM> are shown, but it will be appreciated that the brake <NUM> may comprise a plurality of arms <NUM> spaced around the inner surface of the housing <NUM>.

The arms <NUM> comprise a hinge <NUM> and a brake shoe <NUM>. The hinge <NUM> extends in cantilever fashion away from the inner surface of the housing <NUM> and toward the plunger <NUM>. The brake shoe <NUM> extends from the ends of the hinge <NUM> in a longitudinal direction of the device <NUM>. The brake shoe <NUM> provides a braking surface <NUM> configured to contact the outer surface <NUM> of the plunger <NUM>.

Opposite the braking surface <NUM>, an outer surface <NUM> of the brake shoe <NUM> contacts the inner surface <NUM> of the collar <NUM>. The outer surface <NUM> of the brake shoe <NUM> is provided with a gradient so that the thickness of the brake shoe <NUM> increases in a circumferential direction of the device <NUM>. Therefore, as the collar <NUM> is rotated, the contact pressure between the collar's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> varies in dependence on the direction of rotation of the collar <NUM>. If the collar <NUM> is rotated in the direction of increasing thickness of the brake shoe <NUM>, the contact pressure between the collar's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases. Likewise, if the collar <NUM> is rotated in the opposite direction, said contact pressure decreases.

Increasing the contact pressure between the collar's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases the force with which the brake <NUM> is pressed against the plunger <NUM>.

The inner and outer surfaces <NUM>, <NUM> of the collar <NUM> are connected to each other by at least one connecting portion <NUM>. The connecting portion <NUM> extends through a slot <NUM> in the housing <NUM>. The slot <NUM> extends in the circumferential direction to allow rotation of the collar <NUM>.

<FIG> shows a cross section of the brake force adjustment mechanism <NUM> of <FIG>, taken transversely to the longitudinal axis of the device. In the embodiment illustrated by <FIG>, the inner surface <NUM> of the collar comprises four bumps <NUM> - in this case hemispherical protuberances of the inner surface <NUM> - each in contact with an outer surface <NUM> of a respective brake shoe <NUM>. The bumps <NUM> and brake shoes <NUM> are arranged <NUM> degrees apart to evenly distribute the pressure applied to the outer surface <NUM> of the plunger <NUM>. The connecting portions <NUM> are also arranged <NUM> degrees apart and locate in corresponding slots in the housing (not shown).

In an alternative configuration of the embodiment of <FIG>, the bumps <NUM> of the inner surface <NUM> of the collar <NUM> are omitted and instead the inner surface <NUM> is smooth. In this configuration the inner surface <NUM> is provided with a gradient so that the thickness of an inner portion <NUM> of the collar <NUM> increases in a circumferential direction of the device <NUM>. Therefore, as the collar <NUM> is rotated, the contact pressure between the collar's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> varies in dependence on the direction of rotation of the collar <NUM>. If the collar <NUM> is rotated in the direction of increasing thickness of the inner portion <NUM> of the collar <NUM>, the contact pressure between the collar's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases. Likewise, if the collar <NUM> is rotated in the opposite direction, said contact pressure decreases. In such a configuration, the thickness of the shoe <NUM> may be constant in the circumferential direction.

In another embodiment illustrated by <FIG>, in which like features retain the same reference numbers, the brake force adjustment mechanism <NUM> comprises a sleeve <NUM> which is supported in the proximal region of the housing <NUM> overlapping the plunger <NUM>. The sleeve <NUM> is slidably supported so that a user may slide the sleeve <NUM> along the longitudinal axis A-A of the device <NUM>. Sliding the sleeve <NUM> in one direction increases the injection speed, while sliding the sleeve in the other reduces the injection speed, as will be explained below.

The sleeve <NUM> comprises an outer surface <NUM>, which a user can grip to slide the sleeve <NUM> along the longitudinal axis of the device <NUM>; and an inner surface <NUM>, which is configured to interact with the brake <NUM>. Sliding the sleeve <NUM> in one direction presses the brake <NUM> against the plunger <NUM> with greater force.

The sleeve <NUM> may slide between a first position - representative of a fastest injection speed - and a second position - representative of a slowest injection speed.

In the first position, the brake <NUM> is pressed against the plunger <NUM> with the lowest force. In the second position, the brake <NUM> is pressed against the plunger <NUM> with the greatest force. Sliding the sleeve <NUM> between the first and second positions varies the force with which the brake <NUM> is pressed against the plunger <NUM>. Sliding the sleeve <NUM> toward the second position increases the force with which the brake <NUM> is pressed against the plunger <NUM>. Therefore, the sleeve <NUM> slides to fine tune the injection speed to the patient's preference.

In this embodiment - as in the embodiments of <FIG> and <FIG> - the brake <NUM> is integrally formed with the housing <NUM> and comprises at least one arm <NUM> which extends from the inner surface of the housing <NUM>. In <FIG>, two arms <NUM> are shown, but it will be appreciated that the brake <NUM> may comprise a plurality of arms <NUM> spaced around the inner surface of the housing <NUM>.

The arms <NUM> comprise a hinge <NUM> and a brake shoe <NUM>. The hinge <NUM> extends away from the inner surface of the housing <NUM> and toward the plunger <NUM>. The brake shoe <NUM> extends from the ends of the hinge <NUM> in a longitudinal direction of the device <NUM>. The brake shoe <NUM> provides a braking surface <NUM> configured to contact the outer surface <NUM> of the plunger <NUM>.

Opposite the braking surface <NUM>, an outer surface <NUM> of the brake shoe contacts the inner surface <NUM> of the sleeve <NUM>. The inner surface <NUM> of the sleeve <NUM> is provided with a gradient so that the thickness of an inner portion <NUM> of the sleeve <NUM> increases in a longitudinal direction of the device. Therefore, the contact pressure between the sleeve's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> varies in dependence on the direction in which the sleeve <NUM> slides. If a user slides the sleeve <NUM> in the direction of increasing thickness of the inner portion <NUM> of the sleeve <NUM>, the contact pressure between the sleeve's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases. Likewise, if a user slides the sleeve <NUM> in the opposite direction, said contact pressure decreases.

Increasing the contact pressure between the sleeve's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases the force with which the brake <NUM> is pressed against the plunger <NUM>.

The inner portion <NUM> of the sleeve is connected to an outer portion <NUM> of the sleeve <NUM> by at least one connecting portion <NUM>. The connecting portion <NUM> extends through a slot in the housing <NUM>. The slot extends in the longitudinal direction of the device <NUM> to allow the sleeve <NUM> to slide as described.

<FIG> shows a detail view of an alternative configuration of the embodiment of <FIG> in which the outer surface <NUM> of the brake shoe <NUM> is provided with a gradient so that thickness of the brake shoe <NUM> increases in a longitudinal direction of the device <NUM>. In this embodiment, the inner surface <NUM> of the sleeve <NUM> comprises a bump <NUM> that contacts the outer surface <NUM> of the brake shoe <NUM>. Therefore, the contact pressure between the sleeve's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> varies in dependence on the direction in which the sleeve <NUM> slides. If a user slides the sleeve <NUM> in the direction of increasing thickness of the brake shoe <NUM>, the contact pressure between the sleeve's inner surface <NUM> and the outer surface <NUM> of the brake shoe <NUM> increases. Likewise, if a user slides the sleeve <NUM> in the opposite direction, said contact pressure decreases.

In the above embodiments the region of high friction material <NUM> may comprise a plurality of separate regions of high friction material spaced around the outer surface <NUM> of the plunger <NUM> so that each separate region of high friction material is in contact with the braking surface <NUM> of a respective brake shoe <NUM>. For example, the plurality of separate regions <NUM> comprises four separate regions spaced <NUM> degrees apart.

In the above embodiments, instead of the region of high friction material <NUM>, the plunger <NUM> may be instead provided with at least one channel <NUM> in its outer surface <NUM>, as illustrated by <FIG>. The at least one channel <NUM> is configured to reduce the contact area between the outer surface <NUM> of the plunger <NUM> the braking surface <NUM> of a respective brake shoe <NUM> overlying the channel <NUM>. The width of the channel <NUM> increases toward the proximal end P of the plunger <NUM>. Therefore, the proportion of the braking surface <NUM> of the brake shoe <NUM> overlying the channel <NUM> increases with displacement of the plunger <NUM> toward the end stop, reducing the contact area between the outer surface <NUM> of the plunger <NUM> and braking surface <NUM>. Further, the changing width of the channel <NUM> causes an effective change in the deflection of the brake <NUM>. These effects combined cause a corresponding fall in friction between the braking surface <NUM> and the plunger <NUM> which compensates for the decay in the spring force. The channel is thus configured to cause the plunger <NUM> to move at a constant speed through its full range of movement between the initial position and the end stop position. It shall be appreciated that as well as/instead of changing the width of the channel <NUM>, it is also possible to reduce the friction between the braking surface <NUM> and the plunger <NUM> by increasing the depth of the channel <NUM> toward the proximal end P of the plunger <NUM>. In particular, by increasing the depth of the channel <NUM> the contact pressure between the braking surface <NUM> and the plunger is reduced. In such embodiments, at least part of the braking surface sits within the channel <NUM>.

In the above embodiments, the at least one channel <NUM> may comprise a plurality of separate channels spaced around the outer surface <NUM> of the plunger <NUM> so that each separate channel is disposed below a braking surface <NUM> of a respective brake shoe <NUM>. For example, the plurality of separate channels comprises four separate channels spaced <NUM> degrees apart.

In the above embodiments, the plunger <NUM> may be tapered so that an external diameter of the plunger <NUM> at the distal end of the plunger <NUM> is marginally greater than the external diameter of the plunger <NUM> at the proximal end of the plunger <NUM>. Therefore, during displacement of the plunger <NUM>, the contact force between the brake <NUM> and the plunger <NUM> is declines as the plunger is displaced toward the end stop position.

The embodiments of injector devices described herein are configured to receive either a cartridge of medicament or a syringe pre-filled with a medicament. Herein, the term "medicament container" is intended to encompass both a cartridge of medicament and a pre-filled syringe.

Without limitation, a drug delivery device may be an injector device (e.g., syringe, pen injector, auto injector, large-volume device, pump, perfusion system, or other device configured for intraocular, subcutaneous, intramuscular, or intravascular delivery), skin patch (e.g., osmotic, chemical, micro-needle), inhaler (e.g., nasal or pulmonary), implantable (e.g., coated stent, capsule), or feeding systems for the gastrointestinal tract. The presently described drugs may be particularly useful with injector devices that include a needle, e.g., a small gauge needle.

Exemplary insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin; B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl- ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyhepta¬decanoyl) human insulin. Exemplary GLP-<NUM>, GLP-<NUM> analogues and GLP-<NUM> receptor agonists are, for example: Lixisenatide / AVE0010 / ZP10 / Lyxumia, Exenatide / Exendin-<NUM> / Byetta / Bydureon / ITCA <NUM> / AC-<NUM> (a <NUM> amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide / Victoza, Semaglutide, Taspoglutide, Syncria / Albiglutide, Dulaglutide, rExendin-<NUM>, CJC-<NUM>-PC, PB-<NUM>, TTP-<NUM>, Langlenatide / HM-11260C, CM-<NUM>, GLP-<NUM> Eligen, ORMD-<NUM>, NN-<NUM>, NN-<NUM>, NN-<NUM>, Nodexen, Viador-GLP-<NUM>, CVX-<NUM>, ZYOG-<NUM>, ZYD-<NUM>, GSK-<NUM>, DA-<NUM>, MAR-<NUM>, MAR709, ZP-<NUM>, ZP-<NUM>, TT-<NUM>, BHM-<NUM>. MOD-<NUM>, CAM-<NUM>, DA-<NUM>, ARI-<NUM>, ARI-<NUM>, Exenatide-XTEN and Glucagon-Xten.

Claim 1:
An injector device (<NUM>) comprising:
an outer housing (<NUM>) for receiving a medicament container (<NUM>); and
a drive mechanism (<NUM>) for dispensing medicament from a medicament container (<NUM>) received in the outer housing (<NUM>); the drive mechanism (<NUM>) comprising a plunger rod (<NUM>) and a displacing member (<NUM>) configured to displace a distal end of (<NUM>) the plunger rod (<NUM>) into said medicament container (<NUM>) to dispense said medicament;
wherein the device further comprises a brake (<NUM>) configured to control the rate of displacement of the plunger rod (<NUM>) under the force of the displacing member (<NUM>), the brake (<NUM>) comprising a braking surface (<NUM>) that contacts an outer surface (<NUM>) of the plunger rod (<NUM>) so that movement of the plunger rod (<NUM>) is resisted by friction between the braking surface (<NUM>) and the outer surface (<NUM>) of the plunger rod (<NUM>);
wherein the device further comprises a brake force adjustment mechanism (<NUM>) configured to adjust the contact pressure between the braking surface (<NUM>) and the outer surface (<NUM>) of the plunger rod (<NUM>); characterised in that the brake force adjustment mechanism (<NUM>) comprises a collar (<NUM>) rotatably mounted on the housing (<NUM>), the collar (<NUM>) being rotatable around a longitudinal axis of the device to adjust the contact pressure between the braking surface (<NUM>) and the outer surface (<NUM>) of the plunger rod (<NUM>); or
wherein the brake force adjustment mechanism (<NUM>) comprises a sleeve (<NUM>) slidably mounted to the housing (<NUM>), the sleeve (<NUM>) being configured to slide along a longitudinal axis of the device to adjust the contact pressure between the braking surface (<NUM>) and the outer surface (<NUM>) of the plunger rod (<NUM>).