Medicament delivery device

Abstract

The present invention relates to a medicament delivery device. The medicament delivery device comprises a housing, a needle, and a needle cover. The needle cover is axially movable between an extended position and a retracted position. The medicament delivery device further comprises a needle cover biasing member, a skin sensor, a skin sensor biasing member, and a retaining mechanism. The needle cover biasing member is configured to bias the needle cover axially in the distal direction towards the extended position. The skin sensor extending distally from the distal end of the needle cover and configured to contact an injection site. The skin sensor biasing member acts between the needle cover and the skin sensor. The skin sensor is configured to bias the skin sensor axially in the distal direction from a proximal position to a distal position away from the needle cover. The retaining mechanism is configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a per of the force of the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally. The present invention also relates to a method of preparing a medicament delivery device and a method of extending a needle cover of a medicament delivery device.

Description

[0001] PAT24299-EP-EPA

[0002] Medicament Delivery Device

[0003] Field of the invention

[0004] This application relates to a medicament delivery device.

[0005] Background of the invention

[0006] Medicament delivery devices are used to deliver a range of medicaments.

[0007] In some devices, the device must be held in a holding position at an injection site for a predetermined period of time, to ensure that the correct dose of medicament is dispensed from the device, before removing the device from the injection site.

[0008] It may be difficult to hold the device in the holding position whilst the medicament is dispensed. This may result in pain, discomfort, a wet injection site, early device removal and / or partial delivery of the medicament.

[0009] It is an object of the present invention to provide an improved medicament delivery device.

[0010] Summary of the invention

[0011] According to a first aspect of the present invention, there is provided a medicament delivery device comprising a medicament delivery device comprising a housing comprising a proximal end and a distal end, a needle and a needle cover, wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end of the needle cover, a needle cover biasing member configured to bias the needle cover axially in the distal direction towards the extended position, a skin sensor extending distally from the distal end of the needle cover and configured to contact an injection site, a skin sensor biasing member acting between the needle cover and the skin sensor, the skin sensorbiasing member being configured to bias the skin sensor axially in the distal direction from a proximal position to a distal position away from the needle cover, a retaining mechanism configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0012] Once the needle cover has been moved into the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated. This may be particularly advantageous for users that lack the strength to hold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.

[0013] In some embodiments, the retaining mechanism may be is configured to transfer substantially the full force of the needle cover biasing member to the housing when the needle cover is in the retracted position and the skin sensor is in the proximal position.

[0014] Thus, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated.

[0015] In some embodiments, the retaining mechanism may comprise a proximally extending arm of the needle cover, the arm may comprise a projection on its proximal end, and a catch located on the inner surface of the housing, wherein the projection may be configured to engage the catch when the needle cover is in its retracted position.

[0016] Thus, the biasing force of the needle cover biasing member may be transferred to the housing to reduce the holding force required by the operator.

[0017] In some embodiments, the proximal end of the arm of the needle cover may be deflectable in a radial direction.Thus, the projection of the arm may be deflected so that it can be moved past the catch when the needle cover is moved in the proximal direction towards its retracted position.

[0018] In some embodiments, the projection may comprise an inclined engaging surface.

[0019] Thus, the projection is able to slide against the catch to allow the projection to move radially to disengage from the catch when the skin sensor has been moved distally relative to the needle cover such that the skin sensor is no longer reinforcing the arm of the needle cover.

[0020] In some embodiments, the retaining mechanism may further comprise a proximally extending reinforcing member of the skin sensor configured to prevent the projection disengaging from the catch when the needle cover is held in the retracted position and the skin sensor is held in the proximal position.

[0021] Thus, the reinforcing member can hold the needle cover in place against the housing and cause the biasing force of the needle cover biasing member to be transferred to the housing to reduce the holding force required by the operator.

[0022] In some embodiments, the reinforcing member of the skin sensor may be located radially inwards of the arm of the needle cover.

[0023] Therefore, the reinforcing member can prevent radial inwards movement of the arm of the needle cover, and thus prevent the arm of the needle cover from disengaging the catch of the housing.

[0024] In some embodiments, the needle cover may comprise an annular member having a slot adjacent to the arm, wherein the reinforcing member of the skin sensor may extend and may be moveable axially through the slot.

[0025] Thus, the skin sensor may be located both radially inward and distally of the needle cover whilst also still being able to position the reinforcing member radiallyinwardly of the arm of the needle cover to retain the projection against the catch when the needle cover is in the retracted position.

[0026] In some embodiments, the reinforcing member of the skin sensor may be stiffer than the arm of the needle cover.

[0027] Thus, the reinforcing member may be able to provide the force required to withstand the biasing force of the needle cover biasing member. That is, the reinforcing member may prevent inward movement of the arm of the needle cover. In addition, this means that the stiffness of the arm of the needle cover can be reduced so that it is easier for the needle cover to disengage the housing once the reinforcing member has been moved distally relative to the needle cover.

[0028] In some embodiments, upon depression of the device against an injection site, the skin sensor may be configured to be moved from the distal position to the proximal position before the needle cover is moved from the extended position to the retracted position.

[0029] This may be a result of the differing spring rates or initial compression forces. The arrangement of the needle cover, needle cover biasing member, skin sensor, and skin sensor biasing member may be considered to be a series configuration. That is, the skin sensor biasing member acts between the needle cover and skin sensor.

[0030] In some embodiments, when the needle cover in its retracted position and the skin sensor is in its proximal position relative to the needle cover, the proximal end of the reinforcing member may be located proximally of the proximal end of the arm.

[0031] In some embodiments, when the needle cover in its retracted position and the skin sensor is in its proximal position relative to the needle cover, the proximal end of the reinforcing member may be located proximally of the proximal end of the arm by a predetermined distance and may be configured to prevent unlatching of the retaining mechanism when the medicament delivery device is initially moved away from the injection site.Thus, the skin sensor can protect against accidental partial removal of holding force by the operator. Any such removal of force that results in the distal movement of the skin sensor may not result in release of the needle cover biasing member and distal movement of the needle cover due to the extended length of the reinforcing member because the reinforcing member may still be in contact with a sufficient amount of the arm of the needle cover to prevent unlatching.

[0032] In some embodiments, the needle cover may comprise a skin sensor retaining element extending radially inwardly, and the skin sensor may comprise a longitudinally extending slot in the reinforcing member, the skin sensor retaining element and slot may be configured to limit the longitudinal movement of the skin sensor relative to the needle cover.

[0033] Thus, the skin sensor may be retained in the medicament device and over-extension of the skin sensor and skin sensor biasing member can be prevented.

[0034] In some embodiments, the housing may comprise an inner surface with a ramped portion, the ramped portion may be configured to bias the arm of the needle cover radially inwards, and wherein the catch may be located at the proximal end of the ramper portion of the inner surface.

[0035] Thus, the arm of the needle cover is automatically biased by the proximal movement of the needle cover. The increase in force required by the user to latch the needle cover may increase gradually. This may give an operator of the device feedback on the position of the needle cover relative to the latch.

[0036] In some embodiments, the medicament delivery device may comprise medicament.

[0037] In a second aspect of the present invention, there is provided a method of preparing a medicament delivery device for use, the method comprising moving a skin sensor from a distal position to a proximal position against the force of a skin sensor biasing member, moving the skin sensor and a needle cover proximallyfrom an extended position to a retracted position within a housing, engaging a projection on an arm of the needle cover with a catch located in the housing and maintaining the projection in engagement with the catch located in the housing and maintaining the projection in engagement with the catch with a reinforcing member of the skin sensor, wherein engaging the needle cover with the housing transfers the force of the needle cover biasing member to the housing.

[0038] In a third aspect, there is provided a medicament delivery device comprising a housing comprising a proximal end and a distal end, a needle and a needle cover, wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end of the needle cover, a needle cover biasing member configured to bias the needle cover axially in the distal direction towards the extended position, a skin sensor extending from the distal end of the housing, the skin sensor being axially moveable between a distal position, in which the needle cover is free to move axially, and a proximal position, in which the skin sensor limits axial movement of the needle cover, a skin sensor biasing member configured to bias the skin sensor axially in the distal direction towards its distal position, wherein the skin sensor biasing member acts on the housing at its proximal end and the skin sensor at its distal end, wherein the distal end of the skin sensor is located proximally of the distal end of the needle cover when the needle cover is in its extended position, and a retaining mechanism configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0039] Once the needle cover has been moved into the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated. This may be particularly advantageous for users that lack the strength to hold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.In some embodiments, the retaining mechanism may be is configured to transfer substantially the full force of the needle cover biasing member to the housing when the needle cover in in the retracted position and the skin sensor is in the proximal position.

[0040] Thus, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated.

[0041] In some embodiments, the retaining mechanism may comprise a proximally extending arm of the needle cover, the arm may comprise a projection on its proximal end, and a catch may be located on a structural element of the housing, wherein the projection may be configured to engage the catch when the needle cover is in its retracted position.

[0042] Thus, the biasing force of the needle cover biasing member may be transferred to the housing to reduce the holding force required by the operator.

[0043] In some embodiments, the structural element of the housing may be located radially inwardly of the arm of the needle cover.

[0044] Thus, the needle cover may be located inside of the skin sensor, as the needle cover must interact with the structural element. This allows the skin sensor to cover the needle cover to prevent the needle cover being tampered with.

[0045] In some embodiments, the proximal end of the arm of the needle cover may be deflectable in a radially outward direction.

[0046] In some embodiments, the projection may extend radially inwards and may comprise an inclined engaging surface.

[0047] Thus, the projection may engage the catch of the structural element when the needle cover is in the retracted position. The inclined engaging surface may helpthe projection to disengaged from the catch when the skin sensor is moved into a distal position relative to the needle cover.

[0048] In some embodiments, the retaining mechanism may further comprise a proximally extending reinforcing member of the skin sensor configured to prevent the projection disengaging from the catch when the needle cover is held in the retracted position and the skin sensor is held in the proximal position.

[0049] Thus, the reinforcing member can hold the needle cover in place against the housing and cause the biasing force of the needle cover biasing member to be transferred to the housing to reduce the holding force required by the operator.

[0050] In some embodiments, the reinforcing member of the skin sensor may be located radially outwards of the arm of the needle cover.

[0051] Thus, the reinforcing member may be able to help resist outward radial movement of the arm of the needle cover, and may help to bias the arm of the needle cover towards the catch on the structural element to prevent the needle cover from unlatching from the structural element.

[0052] In some embodiments, upon depression of the device against an injection site, the needle cover may be configured to be moved proximally from its extended position towards its retracted position before the skin sensor is moved from its distal position.

[0053] This is due to the arrangement of the needle cover, needle cover biasing member, skin sensor, and skin sensor biasing member in a parallel configuration. Thus, the needle cover may be moved independently of the skin sensor upon initial depression of the device. That is, the needle cover biasing member acts only on the needle cover and not the skin sensor, whereas the skin sensor biasing member acts only on the skin sensor and not on the biasing member, unless the needle cover contacts the skin sensor.In some embodiments, the needle cover may be movable into an initial depression position in which the distal end of the needle cover extends in the same plane as the distal end of the skin sensor.

[0054] This alignment helps the skin sensor protect against accidental partial removal of holding force by the operator. Any such removal of force that results in the distal movement of the skin sensor may not result in release of the needle cover biasing member and distal movement of the needle cover due to the extended length of the reinforcing member because the reinforcing member may still be in contact with a sufficient amount of the arm of the needle cover to prevent unlatching.

[0055] In some embodiments, the needle cover and skin sensor may be moveable together from the initial depression position into their respective retracted and proximal positions.

[0056] In some embodiments, upon removal of the device from an injection site, the skin sensor may be moveable from its proximal position to its distal position under the force of the skin sensor biasing member before the needle cover is moveable from its retracted position under the force of the needle cover biasing member.

[0057] This may prevent the ability of the needle to be contacted. The device may be moved away from the injection site before the needle cover is released under the force of the needle cover biasing member, avoiding contact with the injection site.

[0058] In some embodiments, the medicament delivery device may comprise medicament.

[0059] In a fourth aspect, there is provided a method of preparing a medicament delivery device for use, the method comprising moving a needle cover from its extended position to an initial compression position against the force of a needle cover biasing member, moving the needle cover and a skin sensor from the initial compression position to their respective retracted and proximal positions against the force of the needle cover biasing member and the skin sensor biasing member, engaging a projection on an arm of the needle cover with a catch locatedon structural element of the housing located radially inwardly of the needle cover, and maintaining the projection in engagement with the catch with a reinforcing member of the skin sensor in a latched position, wherein in the latched position the force of the needle cover biasing member is transferred to the housing.

[0060] In a fifth aspect, there is provided a method of extending a needle cover of a medicament delivery device after medicament has been dispensed from the medicament deliver device, the method comprising removing the medicament delivery device from an injection site, moving the skin sensor distally from a proximal position to a distal position under the force of a skin sensor biasing member, disengaging a projection of an arm of a needle cover from a catch located on a housing under the force of the needle cover biasing member when the skin sensor has reached the distal position, and moving the needle cover in the distal direction from its retracted position to its extended position.

[0061] In a sixth aspect, there is provided a medicament delivery device comprising a housing comprising a proximal end and a distal end, a needle and a needle cover, wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end of the needle cover, a needle cover biasing member configured to bias the needle cover axially in the distal direction towards the extended position, a skin sensor extending from the distal end of the housing, the skin sensor being axially moveable between a distal position, in which the needle cover is free to move axially, and a proximal position, a skin sensor biasing member configured to bias the skin sensor axially in the distal direction towards its distal position, a retaining mechanism comprising a collar axially fixed within the housing, the collar configured to be moveable between a disengaged position when the skin sensor is in its distal position, and an engaged position when the skin sensor is in its proximal position and the needle cover is in its retracted position, in which the collar is configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of theneedle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0062] Once the needle cover has been moved into the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated. This may be particularly advantageous for users that lack the strength to hold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.

[0063] In some embodiments, the retaining mechanism may be configured to transfer substantially the full force of the needle cover biasing member to the housing when the collar is in the engaged position.

[0064] Thus, the holding force required to overcome the distally acting force of the needle cover biasing member may be reduced, if not eliminated.

[0065] In some embodiments, the retaining mechanism may further comprise a proximally extending arm of the needle cover, wherein a proximal end of the arm of the needle cover may comprises an aperture, wherein the collar may be configured to extend through the aperture when the collar is in the engaged position.

[0066] Thus, the collar may prevent distal movement of the needle cover when it extends through the aperture. In this way, the force of the needle cover biasing member may be transferred to the collar by the needle cover eliminating the hold force component of the needle cover biasing member, which reduces the overall hold force required.

[0067] In some embodiments, the collar may be configured to be moved from the disengaged position to the engaged position by movement of the skin sensor from its distal position to its proximal position.

[0068] In some embodiments, the retaining mechanism may further comprise a first proximally extending actuation member of the skin sensor, the first actuationmember may be configured to contact and move the collar into the engaged position when the skin sensor is moved into its proximal position.

[0069] Thus, the collar can be moved into the engaged position to reduce the hold force required by depression of the medicament delivery device against the injection site. The movement of the collar into the engaged position can occur automatically on the initiation of a medicament delivery process.

[0070] In some embodiments, the proximal end of the first actuation member of the skin sensor may comprise an inclined first engaging surface configured to cooperate with a declined first ramped surface of the collar.

[0071] In some embodiments, the proximal end of the first actuation member may comprise an inwardly extending projection forming at least a part of the inclined first engaging surface.

[0072] The inclined surface helps to move the collar gradually from the disengaged position to the engaged position. The projection extends the length of the inclined first engaging surface to enable the collar to be moved over a greater distance.

[0073] In some embodiments, the collar may be configured to be moved from the engaged position to the disengaged position by movement of the skin sensor from its proximal position to its distal position.

[0074] Thus, the collar can be moved into the disengaged position automatically on removal of the medicament delivery device from the injection site.

[0075] In some embodiments, the retaining mechanism may further comprise a second proximally extending actuation member of the skin sensor, the second actuation member may comprise a second aperture configured to receive the collar when the collar is in the engaged position.Thus, the collar can be moved past the arm of the needle cover by a distance that ensures that the needle cover biasing member force cannot accidentally move the collar from the engaged position towards the disengaged position.

[0076] In some embodiments, the proximal end of the aperture of the second actuation member of the skin sensor may comprise a declined second engaging surface configured to cooperate with an inclined first ramped surface of the collar.

[0077] The movement of the collar into the disengaged position can occur automatically on removal of the medicament delivery device from the injection site. The declined surface helps to move the collar gradually from the engaged position to the disengaged position.

[0078] In some embodiments, the needle cover may be movable into an initial depression position in which the distal end of the needle cover extends in the same plane as the distal end of the skin sensor and the first and second apertures are aligned, and the needle cover and skin sensor may be moveable together from the initial depression position into their respective retracted and proximal positions.

[0079] Thus, the movement of the collar is unobstructed between the disengaged and engaged positions.

[0080] In some embodiments, upon removal of the device from an injection site, the skin sensor may be moveable from its proximal position towards its distal position under the force of the skin sensor biasing member and the collar may be moved from its engaged position to its disengaged position before the needle cover is moveable from its retracted position under the force of the needle cover biasing member.

[0081] This may prevent the ability of the needle to be contacted. The device may be moved away from the injection site before the needle cover is released under the force of the needle cover biasing member, avoiding contact with the injection site.In some embodiments, the collar may be rotatable between the disengaged position and the engaged position.

[0082] In some embodiments, the medicament delivery device may comprise medicament.

[0083] In a seventh aspect, there is provided a method of preparing a medicament delivery device for use, the method comprising moving a needle cover from an extended position to a decompression position, moving the needle cover from the decompression position to a retracted position and a skin sensor from a distal position to a retracted position simultaneously, wherein moving the skin sensor from the distal position to the proximal position moves a collar from a disengaged position to an engaged position in which the collar is configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0084] Brief description of the drawings

[0085] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0086] Fig. 1 A shows an injector device with a cap attached;

[0087] Fig. 1 B shows the injector device of Figure 1 A with the cap removed;

[0088] Fig. 2 shows a simplified schematic cross-sectional side view of an example of a medicament delivery device;

[0089] Fig. 3 shows a simplified schematic cross-sectional side view of an example of a medicament delivery device;

[0090] Fig. 4 shows a schematic perspective cross-sectional view of components of a medicament delivery device;

[0091] Fig. 5 shows a schematic cross-sectional side view of a medicament deliver device;

[0092] Figs. 6A to 6G show schematic cross-sectional views of components of a medicament delivery device at various stages of operation;Fig. 7 shows a simplified schematic cross-sectional side view of an example of a medicament delivery device;

[0093] Figs. 8A to 8E show schematic cross-sectional views of components of a medicament delivery device at various stages of operation;

[0094] Fig. 9 shows a schematic cross-sectional view of an example of components of a medicament delivery device; and

[0095] Figs. 10A to 10G show schematic cross-sectional views of components of a medicament delivery device at various stages of operation.

[0096] Detailed description

[0097] A drug delivery device, as described herein, may be configured to inject a medicament into a patient. For example, delivery could be sub-cutaneous, intramuscular, or intravenous. Such a device could be operated by a patient or caregiver, 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 0.5 ml to about 2 ml. Yet 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 5, 15, 30, 60, or 120 minutes) to deliver a “large” volume of medicament (typically about 2 ml to about 10 ml).

[0098] In combination with a specific medicament, the presently described devices may also be customized in order to operate within required specifications. For example, the device may be customized to inject a medicament within a certain time period (e.g., about 3 to about 20 seconds for auto-injectors, and about 10 minutes to about 60 minutes for an LVD). 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 3 cP to about 50 cP. Consequently, a drug delivery device will often include a hollow needle ranging from about 25 to about 31 Gauge in size. Common sizes are 27 and 29 Gauge.The delivery devices described herein can also include one or more automated functions. For example, one or more of 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.

[0099] The one or more automated functions of an auto-injector may each be activated via an activation mechanism. Such an activation mechanism can include one or more of a button, a lever, a needle sleeve, or other activation component.

[0100] 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.

[0101] In addition, activation of one automated function may activate one or more subsequent automated functions, thereby forming an activation sequence. For example, activation of a first automated function may activate at least two of needle insertion, medicament injection, and needle retraction. Some devices may also require a specific sequence of steps to cause the one or more automated functions to occur. Other devices may operate with a sequence of independent steps.

[0102] Some delivery devices can include one or more functions of a safety syringe, peninjector, or auto-injector. For example, a delivery device could include a mechanical energy source configured to automatically inject a medicament (astypically found in an auto-injector) and a dose setting mechanism (as typically found in a pen-injector).

[0103] According to some embodiments of the present disclosure, an exemplary drug delivery device 10 is shown in Figs. 1A & 1B. Device 10, as described above, is configured to inject a medicament into a patient’s body. Device 10 includes a housing 11 which typically contains a reservoir containing the medicament to be injected (e.g., a syringe) and the components required to facilitate one or more steps of the delivery process. Device 10 can also include a cap assembly 12 that can be detachably mounted to the housing 11. Typically a user must remove cap 12 from housing 11 before device 10 can be operated.

[0104] As shown, housing 11 is substantially cylindrical and has a substantially constant diameter along the longitudinal axis X. The housing 11 has a distal region 20 and a proximal region 21. 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.

[0105] Device 10 can also include a needle sleeve 13 coupled to housing 11 to permit movement of sleeve 13 relative to housing 11. For example, sleeve 13 can move in a longitudinal direction parallel to longitudinal axis X. Specifically, movement of sleeve 13 in a proximal direction can permit a needle 17 to extend from distal region 20 of housing 11.

[0106] Insertion of needle 17 can occur via several mechanisms. For example, needle 17 may be fixedly located relative to housing 11 and initially be located within an extended needle sleeve 13. Proximal movement of sleeve 13 by placing a distal end of sleeve 13 against a patient’s body and moving housing 11 in a distal direction will uncover the distal end of needle 17. Such relative movement allows the distal end of needle 17 to extend into the patient’s body. Such insertion is termed “manual” insertion as needle 17 is manually inserted via the patient’s manual movement of housing 11 relative to sleeve 13.Another form of insertion is “automated,” whereby needle 17 moves relative to housing 11. Such insertion can be triggered by movement of sleeve 13 or by another form of activation, such as, for example, a button 22. As shown in Figs.

[0107] 1 A & 1 B, button 22 is located at a proximal end of housing 11. However, in other embodiments, button 22 could be located on a side of housing 11.

[0108] Other manual or automated features can include drug injection or needle retraction, or both. Injection is the process by which a bung or piston 23 is moved from a proximal location within a syringe (not shown) to a more distal location within the syringe in order to force a medicament from the syringe through needle 17. In some embodiments, a drive spring (not shown) is under compression before device 10 is activated. A proximal end of the drive spring can be fixed within proximal region 21 of housing 11 , and a distal end of the drive spring can be configured to apply a compressive force to a proximal surface of piston 23.

[0109] Following activation, at least part of the energy stored in the drive spring can be applied to the proximal surface of piston 23. This compressive force can act on piston 23 to move it in a distal direction. Such distal movement acts to compress the liquid medicament within the syringe, forcing it out of needle 17.

[0110] Following injection, needle 17 can be retracted within sleeve 13 or housing 11. Retraction can occur when sleeve 13 moves distally as a user removes device 10 from a patient’s body. This can occur as needle 17 remains fixedly located relative to housing 11. Once a distal end of sleeve 13 has moved past a distal end of needle 17, and needle 17 is covered, sleeve 13 can be locked. Such locking can include locking any proximal movement of sleeve 13 relative to housing 11.

[0111] Another form of needle retraction can occur if needle 17 is moved relative to housing 11. Such movement can occur if the syringe within housing 11 is moved in a proximal direction relative to housing 11. This proximal movement can be achieved by using a retraction spring (not shown), located in distal region 20. A compressed retraction spring, when activated, can supply sufficient force to the syringe to move it in a proximal direction. Following sufficient retraction, any relative movement between needle 17 and housing 11 can be locked with a locking mechanism. In addition, button 22 or other components of device 10 can be locked as required.Fig. 2 shows a simplified view of a medicament delivery device 100. The medicament delivery device 100 comprises a housing 101. The housing 101 comprises a proximal end 102 and a distal end 103. The medicament delivery device 101 further comprises a needle 105 for injecting medicament and a needle cover 106. The needle 105 has a distal end 107. The needle cover 106 is axially movable relative to the housing 101 between an extended position, in which the needle cover 106 extends from the distal end 103 of the housing 101 and covers the distal end 107 of the needle 105, and a retracted position, in which the needle cover 106 is located in a proximal position relative to the extended position such that the needle 105 protrudes from a distal end 108 of the needle cover 106.

[0112] The medicament delivery device 100 is shown in the extended position in Fig. 2. The extended position may be the initial position in which the medicament delivery device 100 is provided to a user. The medicament delivery device 100 extends along an axis X.

[0113] The medicament delivery device 100 further comprises a needle cover biasing member 111. The needle cover biasing member 111 is configured to bias the needle cover 106 axially in the distal direction towards the extended position. The distal direction is indicated by the direction of the arrow A in Fig. 2. In some embodiments, the needle cover biasing member 111 may be a spring.

[0114] The medicament delivery device 100 may further comprise a plunger rod 115. The plunger rod 115 may be axially movable within the housing 101. The medicament delivery device 100 may further comprise a syringe 116. The syringe 116 may be configured to contain medicament. The syringe 116 may comprise the needle 105 located on a distal end of the syringe 116. The plunger rod 115 may be axially movable within a syringe 116 of the medicament delivery device 100 to dispense medicament from the syringe 116 via the needle 105. The syringe 116 may comprise a piston 117. The plunger rod 115 may act on the piston 117 to dispense medicament from the syringe 116 via the needle 105.The medicament delivery device 100 may further comprise a collar 119. The collar 119 may be axially fixed relative to the housing 101. The collar 119 may interface with the plunger rod 115 via a screw thread 112. The medicament delivery device 100 may further comprise a drive member 124. The drive member 124 may be a biasing member that is configured to rotate the collar 119 when the drive member 124 is released. The drive member 124 may be a rotational biasing member, such as a spring. The spring 124 may be a torsion spring. The torsion spring 124 may be released when the needle cover 106 reaches a predetermined axial displacement in the proximal direction with a release mechanism (not shown). The rotation of the collar 119 may cause the plunger rod 115 to move distally within the syringe 116, in view of the screw thread 122, to thereby dispense medicament from the syringe 116 via the needle 105.

[0115] The needle cover 106 may be moved axially into the housing 101 uncovering the needle 105. The needle cover 106 may be moved proximally into the housing 101 by being pressed against an injection site. The proximal axial displacement of the needle cover 106 may cause the release of the spring 124 which rotates the collar 119. The rotation of the collar 119 may move the plunger rod 115 axially in the distal direction within the syringe 116 to dispense the medicament via the needle 105.

[0116] The medicament delivery device 100 may be pressed against the injection site, to hold the needle cover 106 in the retracted position whilst the medicament is dispensed from the medicament delivery device 100. In known medicament delivery devices, the user must hold the medicament delivery device 100 against the injection site against the force of the needle cover biasing member 111.

[0117] After the medicament has been dispensed, the medicament delivery device 100 is removed from the injection site. The needle cover 106 may move distally under the force of the needle cover biasing member 111 to a locked position. In the locked position, the needle cover 106 covers the distal end 107 of the needle 105. In the locked position, the needle cover 106 may be prevented from moving proximally.The medicament delivery device 100 may be configured to inject greater than 2ml of medicament and / or the medicament delivery device 100 is configured to inject medicament having a viscosity of greater than 25cP.

[0118] Fig. 3 shows a simplified cross-sectional view of a medicament delivery device 200. The medicament delivery device 200 is generally similar to the medicament delivery device 100 described in Fig. 2, and functions in a similar way. Therefore, a detailed description will be omitted herein for the sake of brevity. However, the medicament delivery device 200 of Fig. 3 is different to the medicament delivery device 100 of Fig. 2 in that the medicament delivery device 200 is in the form of a flat form medicament delivery device 200. The flat form medicament delivery device 200 may also be described as a large volume device.

[0119] The flat form medicament delivery device 200 has a main body 202, which is arranged to receive a medicament cartridge or container of medicament 204. The main body 202 also contains a needle carrier 215 carrying a needle 216 for the delivery of medicament to a user. The needle carrier 215 is movable with respect to the main body 202.

[0120] The flat form medicament delivery device 200 has a needle cover 218 that is movable between an extended position and an activated position. In the extended position, the needle cover218 covers the needle 216. The needle cover218 extends past the distal most end of the needle 216 to protect a user from needle sticks. In the retracted position, the needle 216 protrudes from a distal end of the needle cover 218. The retracted position is for delivery of medicament from the flat form medicament delivery device 200.

[0121] The needle cover 218 has a contact face 219 for contacting an injection site, for example a user’s skin. The needle cover 218 also has needle cover side walls 217, which extend into the main body 202.

[0122] Fig. 4 shows a simplified perspective cross-sectional view of components of a medicament delivery device 300, Fig. 5 shows a simplified cross-sectional side view of components of a medicament delivery device 300, and Figs. 6A to 6Gshow simplified schematic side cross-sectional views of a medicament delivery device 300 at various stages of operation of the medicament delivery device 300. To reduce complexity and replication of subject-matter in the drawings, the crosssections shown in Figs. 6A to 6G show only one lateral half of the distal end of the medicament delivery device 300.

[0123] The features described and / or contemplated in relation to the medicament delivery device 300 may be incorporated into the medicament delivery devices 100, 200 described and / or contemplated above. In the following described embodiment, the features relating to the needle cover 106, 218 and the needle cover biasing member 111 are modified compared to the medicament delivery devices 100, 200 shown in Figs. 2 and 3.

[0124] It will be appreciated that the following modifications may be applied to the medicament delivery device 100 of Fig. 2 and the flat form medicament delivery device 200 of Fig. 3. For example, the skin sensor 331 of the medicament delivery device 300 may be the component identified by reference numeral ‘227’ in Fig. 3.

[0125] The medicament delivery device 300 comprises a housing 301. The housing 301 comprises a proximal end (not shown in Figs. 4, 5, and 6A to 6G) and a distal end 303, as shown in Fig. 4. The medicament delivery device 300 further comprises a needle 305 and a needle cover 306. The needle cover 306 is axially movable between an extended position, shown in Fig. 6A, and a retracted position, shown in Fig. 6C.

[0126] In the following description the term axially can be understood to be parallel to the main extension of the needle 305 comprising the distal end of the needle 305. Thus, it will be understood that when the present invention in the following description is applied to a medicament delivery device 100 such as that shown in Fig. 2 the axial direction may extend parallel to the longitudinal axis of the medicament delivery device 100, and when the present invention in the following description is applied to a flat form medicament delivery device 200 such as shown in Fig. 3 the axial direction may extend perpendicularly to the longitudinal axis of the flat form medicament delivery device 200 or the direction of movementof the plunger 206. Thus, the terms distally and proximally may also be understood to mean relative to the injection site that than relative to ‘longitudinal ends’ of the body or housing of the flat form medicament delivery device 200.

[0127] In the extended position, the needle cover 306 extends from the distal end 303 of the housing 301 and covers a distal end 307 of the needle 305, as shown in Fig. 4. In the retracted position, the needle cover 306 is located in a proximal position relative to the extended position. In the retracted position, the needle cover 306 is proximally located such that the needle 305 protrudes from a distal end 308 of the needle cover 306. The medicament delivery device 300 also comprises a needle cover biasing member 311. The needle cover biasing member 311 is configured to bias the needle cover 306 axially in the distal direction towards the extended position.

[0128] The medicament delivery device 300 comprises a skin sensor 331 , as shown in Fig. 4. The skin sensor 331 extends distally from the distal end of the needle cover 306. The skin sensor 331 is configured to contact an injection site Furthermore, the medicament delivery device 300 also comprises a skin sensor biasing member 332. The skin sensor biasing member 332 is configured to bias the skin sensor 331 axially in the distal direction towards a distal position away from the needle cover 306.

[0129] The medicament delivery device 300 further comprises a retaining mechanism 335. The retaining mechanism 335 is configured to temporarily retain the needle cover 306 in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member 311 to the housing 301. Thus, the needle cover biasing member 311 is prevented from moving the needle cover 306 distally.

[0130] One advantage of this arrangement is that once the needle cover 306 has been moved to the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member 311 is reduced, if not completely eliminated. This may be particularly advantageous for users that lack strength tohold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.

[0131] In some embodiments, the retaining mechanism 335 may be configured to transfer substantially the full force of the needle cover biasing member 311 to the housing 301 when the needle cover 306 is in the retracted position and the skin sensor 331 is in the proximal position, as shown in Fig. 6D.

[0132] In some embodiments, the spring rate of the needle cover biasing member 311 may be greater than the spring rate of the skin sensor biasing member 332. The spring rate and the compression distance of the skin sensor biasing member 332 may be configured such that the skin sensor 331 may be moved from its distal position to its proximal position relative to the needle cover 306 before the reaction force in the skin sensor biasing member 332 is larger than the reaction force in the needle cover biasing member 331 whilst the needle cover 306 remains in its extended position. Therefore, the skin sensor biasing member 332 may be compressed before the needle cover biasing member 311 is compressed. When the needle cover 306 is in its retracted position and the skin sensor 331 is in its proximal position relative to the needle cover 306, the distal end of the needle 305 may extend beyond the distal end of the skin sensor 331.

[0133] In some embodiments, the spring rate of the needle cover biasing member 311 may be the same as the spring rate of the skin sensor biasing member 332. In such embodiments, the initial compressions of the needle cover biasing member 311 and the skin sensor biasing member 332 may be different. For example, the needle cover biasing member 311 may have a greater amount of initial compression than the skin sensor basing member 332. Therefore, upon an operator pushing the medicament delivery device 300 against an injection site, only the skin sensor biasing member 332 maybe compressed initially, leading to proximal movement of the skin sensor 331 relative to the needle cover 306.

[0134] It will be appreciated that in some embodiments, the spring rates of the needle cover biasing member 311 and the skin sensor biasing member 332 may be different and the needle cover biasing member 311 and the skin sensor biasingmember 332 may have different amounts of initial compression. These two parameters can be determined to achieve the desired sequence of movement of the needle cover 306 and the skin sensor 331. For example, the needle cover 306 may not move axially until the skin sensor 331 contacts the needle cover 306. In other embodiments, the needle cover 306 may begin to move proximally before the skin sensor 331 is in contact with the needle cover 306.

[0135] Referring to Fig. 4 and Fig. 5, the needle cover 306 may comprise a body portion 341. The body portion 341 of the needle cover 306 may be the distal-most portion of the needle cover 306. The body portion 341 of the needle cover 306 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300, as shown in Fig. 4. The body portion 341 of the needle cover 306 may be configured to prevent access to the needle 305 when the needle cover 306 is in the extended position. This may help to prevent accidental contact with the needle 305.

[0136] The body portion 341 of the needle cover 306 may be annular. That is, the body portion 341 of the needle cover 306 may comprise an aperture 342. The aperture 342 maybe located centrally in the body portion 341 of the needle cover 306. The aperture 342 may extend through the full thickness of the body portion 341 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300. The aperture 342 may be configured to allow the needle 305 to extend therethrough when the needle cover 306 is in the retracted position. The body portion 341 may also be referred to as an annular member.

[0137] The needle cover 306 may further comprise an arm 344. The arm 344 of the needle cover 306 may extend in the proximal direction. The arm 344 may extend proximally from the body portion 341 of the needle cover 306. That is, the arm 344 of the needle cover 306 may extend proximally from a proximal facing surface 345 of the body portion 341 of the needle cover 306. The arm 344 may extend from, or proximate to, the periphery of the body portion 341 of the needle cover 306.

[0138] The arm 344 may be elongate such that the length dimension of the arm 344 is greater than the width and thickness dimensions of the arm 344. The arm 344 mayextend around only a section of the circumference of the body portion 341 of the needle cover 306, for example, but not limited to 10% to 20% of the circumference of the needle cover 306. Therefore, the arm 344 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0139] The arm 344 may comprise a proximal end 347 spaced from the body portion 341 of the needle cover 306. The proximal end 347 of the arm 344 may comprise a projection 348. The projection 348 may form a latch 348, as will be explained in more detailed hereinafter. The projection 348 may extend radially outwards from the proximal end 347 of the arm 344 of the needle cover 306.

[0140] In some embodiments, the projection 348 may have a first engaging surface 351 and a second engaging surface 352. The first engaging surface 351 of the projection 348 may be generally distally facing. In some embodiments, the first engaging surface 351 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0141] The second engaging surface 352 of the projection 348 may be generally radially facing. In some embodiments, the second engaging surface 352 may extend parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0142] However, it will be appreciated that in some embodiments, the second engaging surface 352 may inclined relative to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300 when the needle cover 306 is in the extended position, as shown in Fig. 6A.

[0143] In some embodiments, the proximal end 347 of the arm 344 may further comprise a protrusion 349, as shown in Fig. 4 and Fig. 6A. The protrusion 349 may form a skin sensor engaging element 349, as will be explained in more detail hereinafter. The protrusion 349 may extend radially inwardly from the proximal end 347 of the arm 344 of the needle cover 306. The protrusion 349 may comprise a skin sensor engaging surface 353. The skin sensor engaging surface 353 may be in radiallyinnermost part of the protrusion 349. The skin sensor engaging surface 353 may extend parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0144] In some embodiments, as shown in Fig. 6A, the arm 344 of the needle cover 306 may extend proximally parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300 when the needle cover 306 is in the extended position. The arm 344 of the needle cover 306 may be deflectable in a radially inward direction, i.e. toward the central longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300. The arm 344 of the needle cover 306 may be resiliently deflectable such that it returns to its original parallel alignment with the longitudinal axis X’ one the external deflecting force is removed.

[0145] However, it will be appreciated that in an alternative embodiment, a portion of the arm 344 proximate the proximal end 347 of the arm 344 may be biased radially inwards.

[0146] In some embodiments, the needle cover 306 may further comprise a slot 355. The slot 355 may extend through the thickness of the body portion 341 of the needle cover 306 in the longitudinal direction X’ of the retaining mechanism 335 of the medicament delivery device 300. The slot 355 may be configured to receive a portion of the skin sensor 331, as will be explained in more detail hereinafter. In some embodiments, the slot 355 may be arcuate. That is, the slot 355 may extend in the circumferential direction. The slot 355 may be located radially inward of the arm 344 of the needle cover 306. In some embodiments, the slot 355 in the body portion 341 of the needle cover 306 may be located radially adjacent to the point at which the arm 344 extend proximally from the body portion 341 of the needle cover 306.

[0147] Referring to the cross-sectional view of Fig. 5, the needle cover 306 may further comprise a skin sensor retaining element 356. The skin sensor retaining element 356 may be located on the arm 344 of the needle cover 306. That is, the arm 344 of the needle cover 306 may comprise the skin sensor retaining element 356. Theskin sensor retaining element 356 may be configured to retain the skin sensor 331 at least partially within the needle cover 306. That is, the skin sensor retaining element 356 may be configured to limit the travel of the skin sensor 331 relative to the needle cover 306. Thus, the skin sensor retaining element 356 may be configured to prevent the skin sensor 331 from disengaging from the needle cover 306 under the biasing force of the skin sensor biasing member 332.

[0148] The skin sensor retaining element 356 may comprise a projection 357. The projection 357 may extend radially inwards from an inner surface of the arm 344 of the needle cover 306. The projection 357 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 335. The projection 357 may be inclined such that its free end 357a is located proximally relative to its mounting point of the arm 344 of the needle cover 306. Thus, the projection 357 may form a clip or catch. The projection 357 may be configured to engage a corresponding feature on the skin sensor 331 , as will be explained in more detail hereinafter.

[0149] As shown in Fig. 4, the needle cover 306 may comprise a plurality of arms 344. The plurality of arms 344 may be spaced circumferentially about the body portion 341 of the needle cover 306. The plurality of arms 344 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 200. In embodiments where two arms 344 are present, the arms 344 may be located diametrically opposite each other. In addition, the needle cover 306 may comprise a plurality of slots 355. The number of slots 355 may be at least equal to the number of arms 344.

[0150] In some embodiments, the needle cover 306 may comprise a retaining member 358. In some embodiments, the retaining member 358 may be a part of the arm 344. In some embodiments, the retaining member 358 may be a separate feature to the arm 344. The retaining member 358 may extend proximally from the body 341 of the needle cover 306. In some embodiments, the retaining member 358 may be located circumferentially between the arms 344 of the needle cover 306.

[0151] The retaining member 358 may comprise a longitudinally extending slot 358a. The housing 301 may comprise a retaining member 359 extending radially inwardsfrom its inner surface. The retaining member 359 and slot 358a may be configured to limit distal movement of the needle cover 306 relative to the housing 301. Thus, the needle cover 306 can be retained at least partially within the housing 301 against the force of the needle cover biasing member 311.

[0152] Referring to Fig. 4 and Fig. 5, the skin sensor 331 may comprise a body portion 361. The body portion 361 of the skin sensor 331 may be the distal-most portion of the skin sensor 331. The skin sensor 331 may comprise a distal facing surface 362. The distal facing surface 362 may be configured to be placed against an injection site. The body portion 361 of the skin sensor 331 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300, as shown in Fig. 4.

[0153] The body portion 361 of the skin sensor 331 may be annular. That is, the body portion 361 of the skin sensor 331 may comprise an aperture 363. The aperture 363 may be located centrally in the body portion 341 of the skin sensor 331. The aperture 363 may extend through the full thickness of the body portion 361 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0154] The aperture 363 may be configured to allow the needle 305 to extend therethrough when the skin sensor 331 is in the proximal position and the needle cover 306 is in the retracted position.

[0155] The skin sensor 331 may further comprise a reinforcing member 364. The reinforcing member 364 of the skin sensor 331 may extend in the proximal direction. The reinforcing member 364 may extend proximally from the body portion 361 of the skin sensor 331. That is, the reinforcing member 364 of the skin sensor 331 may extend proximally from a proximal facing surface 365 of the body portion 361 of the skin sensor 331.

[0156] The reinforcing member 364 may be elongate such that the length dimension of the reinforcing member 364 is greater than the width and thickness dimensions of the reinforcing member 364. The reinforcing member 364 may extend around onlya section of the circumference of the body portion 361 of the skin sensor 331 , for example, but not limited to 10% to 20% of the circumference of the skin sensor 331. Therefore, the reinforcing member 364 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0157] The reinforcing member 364 may comprise a proximal end 367 spaced from the body portion 361 of the skin sensor 331. The proximal end 367 of the reinforcing member 364 may be configured to be located at a more proximal axial point within the medicament deliver device 300 as the proximal end 347 of the arm 344 of the needle cover 306 when the skin sensor 331 is in its proximal position, as shown in Fig. 6B to Fig. 6D, as will be explained in more detail hereinafter.

[0158] Therefore, in some embodiments, the length dimension of the reinforcing member 364 of the skin sensor 331 may be greater than the length dimension of the arm 344 of the needle cover 306. In some embodiments, the reinforcing member 364 may have similar width dimensions to the arm 344 of the needle cover 306. In some embodiments, the reinforcing member 364 may have similar or greater thickness dimensions (in the radial direction) to the arm 344 of the needle cover 306.

[0159] As shown in Figs. 6B to Fig. 6D, the reinforcing member 364 of the skin sensor 331 may have a length that is greater than the length of the arm 344 of the needle cover 306 such that the proximal end 367 of the reinforcing member 364 is located proximally of the proximal end 347 of the arm 344 when the skin sensor 331 is in its proximal position relative to the needle cover 306. One advantage of such an embodiment is that the skin sensor 331 may be able to move further in the distal direction before the needle cover 306 can disengage with the housing 301 to move back towards the extended position, as will be explained in more detail herein after.

[0160] As shown in Fig. 4 and Fig. 5, the reinforcing member 364 of the skin sensor 331 may comprise a distal portion 364a and a proximal portion 364b. The distal portion 364a may extend from the body portion 361 of the skin sensor 331. The proximalportion 364b of the reinforcing member 364 may extend from a proximal end of the distal portion 364a of the reinforcing member 364. The proximal end 367 of the reinforcing member 364 may be located at the proximal end of the proximal portion 364b of the reinforcing member 364.

[0161] The distal portion 364a of the reinforcing member 364 may have a greater thickness dimension that the proximal portion 364b of the reinforcing member 364. That is, the proximal portion 364b may be thinner than the distal portion 364a of the reinforcing member 364. Advantageously, the reduced thickness of the proximal portion 364b of the reinforcing member 364 enables the reinforcing member 364 to have greater flexibility. The thickness of the proximal portion 364b of the reinforcing member 364 may be tuned to provide the required thickness, as will be explained in more detail hereinafter.

[0162] Referring to Fig. 5, the skin sensor 331 may further comprise a slot 368. The slot 368 may be located in the reinforcing member 364 of the skin sensor 331. That is, the reinforcing member 364 of the skin sensor 331 may comprise the slot 368. The slot 368 may be configured to receive the skin sensor retaining element 356 (projection 357) on the arm 344 of the needle cover 306. The slot 368 may comprise a stop 368a at its closed proximal end. In an alternative embodiment, the slot 368 may be located on a different proximally extending extension of the skin sensor 331 that is different to the reinforcing member. The slot 368 may be configured to engage the skin sensor retaining element 356 of the needle cover 306. Thus, where the skin sensor retaining element 356 of the needle cover 306 is not located on the arm 344 of the needle cover 306, the slot 368 of the skin sensor 331 will not be located on the reinforcing member 364 but on a proximal extension configured to interact with the skin sensor retaining element 356 of the needle cover 306.

[0163] The slot 368 and its stop 368a may be configured to cooperate with the skin sensor retaining element 356 of the needle cover 306 to retain the skin sensor 331 at least partially within the needle cover 306. That is, the slot 368 and projection 357 may be configured to limit the travel of the skin sensor 331 relative to the needle cover 306. Thus, the slot 368 and projection 357 may be configured toprevent the skin sensor 331 from disengaging from the needle cover 306 under the biasing force of the skin sensor biasing member 332.

[0164] The slot 368 may extend radially through the thickness of the retaining member 364. However, it will be appreciated that in alternative embodiments, the slot 368 may extend only partially through the thickness of the retaining member 359 in the radial direction. The slot 368 may extend parallel to the longitudinal axis X’ of the retaining mechanism 335. The proximal end of the slot 364, i.e. the stop 364a, may be located proximate to the proximate end 367 of the reinforcing member 364.

[0165] As shown in Fig. 4 and Fig. 5, the skin sensor 331 may comprise a plurality of reinforcing members 364. The plurality of reinforcing members 364 may be spaced circumferentially about the body portion 341 of the skin sensor 331. The plurality of reinforcing members 364 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300. In some embodiments where two reinforcing members 364 are present, the reinforcing members 364 may be located diametrically opposite each other.

[0166] In some embodiments, the skin sensor 331 may comprise a flange 369. The flange 369 may be a part of the body portion 361 of the skin sensor 331 that extends beyond the reinforcing member 364. The flange 369 may extend radially outwardly relative to the reinforcing member 364 of the skin sensor 331. The flange 369 may be configured to abut against a distal end 308 of the needle cover 306 when the skin sensor 331 is in the proximal position relative to the needle cover 306. Therefore, once the required proximal movement of the skin sensor 331 has been achieved, any further compressive force applied by an operator of the medicament delivery device 300 may be transferred to the needle cover 306 to begin compressing the needle cover biasing member 311.

[0167] The slot 368 accommodating the skin sensor retaining element 356 may be located and have a length dimension that enables the flange 369 to contact the distal end 307 of the needle cover 306 before the distal end of the slot 368 contacts the projection 357 of the skin sensor retaining element 356.As shown in Fig. 4 and Fig. 5, the reinforcing member 364 of the skin sensor 331 maybe located in the slot 355 in the body portion 341 of the needle cover 306. The slot 355 may be configured to allow the reinforcing member 364 to move axially therethrough. Thus, the reinforcing member 364 of the skin sensor 331 may be located radially inward of the arm 344 of the needle cover 306.

[0168] As shown in Fig. 4, the housing 301 may comprise a catch 371. The catch 371 may be configured to cooperate with the projection 348 of the needle cover 306 when the needle cover 306 is in the retracted position and the skin sensor 331 is in its proximal position, as shown in Fig. 6D. In some embodiments, the catch 371 may be formed by a recess 372 in the inner surface 373 of the housing 301.

[0169] In some embodiments, the inner surface 373 of the housing 301 may comprise a ramped portion 373a. The ramped portion 373a of the inner surface 373 of the housing 301 may extend radially inwardly towards the central longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300. The proximal end of the ramped portion 373a of the inner surface 373 may extend further in the radial direction that the distal end of the ramped portion 373a of the inner surface 373. That is, the proximal end of the ramped portion 373a of the inner surface 373 may be closer to the longitudinal axis X’ of the retaining mechanism 335 than the distal end of the ramped portion 373a. The ramped portion 373a of the inner surface 373 of the housing 301 may extend linearly between the distal and proximal ends. The ramped portion 373a of the inner surface 373 may be located distally adjacent to the catch 371.

[0170] The catch 371 may be formed by a generally proximally facing surface 374 of the ramped portion 373a of the inner surface 373 of the housing 301 , i.e. of the recess 372. The proximally facing surface 374 may extend in a that is inclined relative to the longitudinal axisX’ of the retaining mechanism 335. The inclined plane of the proximally facing surface 374 may extend such that its distal end is further radially inward compared to its proximal end. The catch 371 maybe profiled to match the surface profile of the first engaging surface 351 of the projection 348 of the needlecover 306. That is, the geometry of the recess 372 may be profiled to match the shape of the projection 348 of the needle cover 306.

[0171] The ramped portion 373a of the inner surface 373 of the housing 301 and the proximally facing surface 374 of the recess 372 in the housing 301 may meet at an apex 375.

[0172] The retaining mechanism 335 may comprise the proximally extending arm 344 of the needle cover 306, the projection 348 located on the proximal end 347 of the arm 344, and the catch 371 located on the inner surface 373 of the housing 301. The projection 348 may be configured to engage the catch 371 when the needle cover 306 is in its retracted position, as shown in Fig. 6D.

[0173] In some embodiments, the retaining mechanism 335 may comprise the proximally extending reinforcing member 364 of the skin sensor 331. The reinforcing member 364 may be configured to prevent the projection 348 from disengaging from the catch 371 when the needle cover 306 is held in the retracted position and the skin sensor 331 is held in the proximal position.

[0174] Referring to Fig. 4 and Fig. 5, a schematic view of the distal end of the medicament delivery device 300 is shown. In Fig. 6A, the needle cover biasing member 311 is extended such that the needle cover 306 is located in its extended position. The needle cover biasing member 311 may act on a proximal facing surface 345 of the body portion 341 of the needle cover 306 and on a structural element 381 of the housing 301 , shown in Fig. 4. The needle cover biasing member 311 may be located radially inwardly of the arm 344 of the needle cover 306.

[0175] In Fig. 4 and Fig. 5, the skin sensor biasing member 332 is extended such that the skin sensor 331 is in its distal position. That is, the skin sensor biasing member 332 biases the skin sensor 331 away from the needle cover 306. The skin sensor biasing member 332 may act on a proximal facing surface 365 of the skin sensor 331 and on a distal facing surface 343 of the needle cover 306, as shown in Fig. 4. The skin sensor biasing member 332 may be located radially inwardly of thereinforcing member 364 of the skin sensor 331. The reinforcing member 364 of the skin sensor 331 may extend through the slot 355 in the body portion 341 of the needle cover 306.

[0176] When the medicament delivery device 300 in this state, as shown in Figs. 4, 5, and 6A, i.e. before use, the proximal end 367 of the reinforcing member 364 of the skin sensor 331 may be located distally from the proximal end 347 of the arm 344 of the needle cover 306. In addition, the projection 348 on the arm 344 of the needle cover 306 may be located at the distal end of the ramped portion 373a of the inner surface 373 of the housing 301.

[0177] Referring to Fig. 6B, upon placement of the medicament delivery device 300 against an injection site, downward pressure on the medicament delivery device 300 may cause the skin sensor biasing member 332 to compress. Thus, the skin sensor 331 may be moved from its distal position, as shown in Fig. 6A, towards its proximal position, shown in Fig. 6C, against the biasing force of the skin sensor biasing member 332.

[0178] In some embodiments, due to the difference in the spring rates and / or initial compression of the needle cover biasing member 311 and the skin sensor biasing member 332, and therefore forces exerted by each, the skin sensor biasing member 332 may be moved to its compressed state before any substantial compression of the needle cover biasing member 311 occurs, as shown in Fig. 6B. In some embodiments, due to the different initial compressions of the needle cover biasing member 311 and the skin sensor biasing member 332, the skin sensor biasing member 332 may be moved to its compressed state before any further substantial compression of the needle cover biasing member 311 occurs. It will be appreciated that the compressed state of the biasing members may refer to the maximum compression achieved within the operation of the medicament delivery device 300 rather than the total overall compression achievable by the needle cover biasing member 311 and the skin sensor biasing member 332.

[0179] Therefore, the skin sensor 331 may be moved into its proximal position relative to the needle cover 306 before the needle cover 306 is moved from its extendedposition. As shown in Fig. 6B, the proximal end 367 of the skin sensor 331 may be located proximally of the proximal end 347 of the needle cover 306. Additionally, the projection 348 of the needle cover 306 may remain distal of, or on the distal end of, the ramped portion 373a of the inner surface 373 of the housing 301. That is, the needle cover 306 may have remained in its extended position without moving proximally. At this stage, the distal end 308 of the needle cover 306 may abut the flange 369 of the skin sensor 331.

[0180] In embodiments where the arm 344 of the needle cover 306 is biased inwardly, movement of the skin sensor 331 into its proximal position may bias the proximal end 347 of the arm 344 outwards such that the proximal end 347 of the arm 344 extends parallel to the longitudinal axis X’ of the retaining mechanism 335 of the medicament delivery device 300.

[0181] Referring now to Fig. 6C, the needle cover 306 has been moved proximally from its extended position towards its retracted position. The skin sensor 331 may move together with the needle cover 306 such that the proximal ends 347, 367 of the needle cover 306 and the skin sensor 331 remain in the same positions relative to each other in the longitudinal direction.

[0182] As the needle cover 306 and skin sensor 331 are moved proximally, the projection 348 of the needle cover 306 engages the ramped portion 373a of the inner surface 373 of the housing 301. Engagement between the projection 348 of the needle cover 306 and the ramped portion 373a of the inner surface 373 of the housing 301 may cause the proximal end 347 of the arm 344 to be biased radially inwards. Bending of the arm 344 radially inwards causes the proximal end 367 of the reinforcing member 364 to move radially inwards.

[0183] The further the needle cover 306 and the skin sensor 331 are moved in the proximal direction, the further the ramped portion 373a of the inner surface 373 of the housing extends radially towards the longitudinal axis X’ of the retaining mechanism 335. Therefore, the further the needle cover 306 and the skin sensor 331 are moved in the proximal direction, the further the projection 348 on the proximal end 347 of the arm 344 of the needle cover 306 and the proximal end367 of the reinforcing member 364 are moved radially inward toward the longitudinal axis X’ of the retaining mechanism 335.

[0184] As a result, the operator of the medicament delivery device 300 may feel an increase in the force required to depress the medicament delivery device 300 against an injection site. The increase in force is required to overcome friction and the resistance to bending of the arm 344 of the needle cover 306 and the reinforcing member 364 of the skin sensor 331. It will be appreciated that the incline and length of the ramped portion 373a of the inner surface of the housing 301 as well as the length, width, and thickness of the arm 344 and reinforcing member 364, and material that the needle cover 306 and skin sensor 331 are formed from may be tailored to provide a minimal increase in force required to depress the medicament delivery device 300 against an injection site whilst providing the benefits of the retaining function described herein.

[0185] When the needle cover 306 is moved sufficiently in the proximal direction, the needle cover 306 may reach its retracted position, as shown in Fig. 6D. In this position, the projection 348 may be located on the catch 371 , or in in the recess 372. In this position, the projection 348 may be configured to engage the catch 371. That is, the first engaging surface 351 of the projection 348 may contact the proximally facing surface 374 of the catch 371. The reinforcing member 364 of the skin sensor 331 may prevent the projection 348 disengaging from the catch 371 when the needle cover 306 is held in the retracted position and the skin sensor 331 is in its proximal position relative to the needle cover 306. This may be achieved by the operator holding the medicament delivery device 300 depressed against the injection site. Thus, the biasing force of the needle cover biasing member 311 may be transferred to the housing 301 of the medicament delivery device 300. This may reduce the hold force required by the operator during operation of the medicament delivery device 300.

[0186] For example, whilst the projection 348 is located in the recess 372, the needle cover biasing member 311 may exert a force on the needle cover 306 in an attempt to return the needle cover 306 to its extended position. However, the projection 348 may abut against the proximally facing surface 374 of the catch 371such that the force of the needle cover biasing member 311 may be transferred to the housing 301.

[0187] Due to the inclined engaging surface 351 of the projection 348, the distally acting force of the needle cover biasing member 311 may cause the engaging surface 351 of the projection 348 to slide against the catch 371 , which may result in the proximal end 347 of the arm 344 deflecting inwards. Sufficient distal movement of the needle cover 306 may result in the projection 348 disengaging with the catch 371.

[0188] However, the reinforcing member 364 of the skin sensor 331 may abut the skin sensor engaging surface 353 of the protrusion 349 located on the inner surface of the proximal end 347 of the arm 344 of the needle cover 306. Thus, the skin sensor 331 may be configured to prevent, or at least resist, the inward deflection of the projection 348 of the proximal end 347 of the arm 344 under the distally acting force of the needle cover biasing member 311. In some embodiment, the reinforcing member 364 of the skin sensor 331 may be stiffer than the arm 344 of the needle cover 306. Thus, as the projection 348 cannot be disengaged with the catch 371 when the needle cover 306 is in the retracted position and the skin sensor 331 is in the proximal position relative to the needle cover 306, due to an operator holding the medicament delivery device 300 against an injection site, the biasing force of the needle cover biasing member 311 may be transferred to the housing 301.

[0189] In some embodiments, the resilience of the reinforcing arm 364 may assist in moving the projection 348 of the arm 344 into its latching position on the catch 371. That is, when the first engaging surface 351 of the projection 348 passes the apex 375 of the housing 301 , the stiffness of the reinforcing member 364 may contribute to biasing the projection 348 into the catch 371. This may reduce the force required by the operator to move the needle cover 306 into its proximal latched position at the very end of the depression of the medicament delivery device 300.Referring now to Fig. 6E, once the medicament delivery device 300 is removed from the injection site, the compressive forces on the needle cover biasing member 311 and the skin sensor biasing member 332 may be removed. In the case shown in Fig. 6E, the retaining mechanism 335 is shown at a point where the operator has either begun to deliberately remove the medicament delivery device 300 from the injection site or has accidentally slightly reduced downward pressure on the medicament delivery device 300 and the injection site.

[0190] In the case of accidental partially removal of the medicament delivery device 300 from the injection site, the skin sensor 331 may be urged distally from its proximal position towards its distal position relative to the needle cover 306 by the skin sensor biasing member 332, as shown in Fig. 6E. However, due to the proximal end 367 of the reinforcing member 364 being located in a more proximal position than the proximal end 347 of the arm 344 when the skin sensor 331 is in its proximal position, the skin sensor 331 may move distally relative to the needle cover 306 by a predetermined distance before the projection 348 may disengage the catch 371 and recess 372 of the housing 301. In some embodiments, the predetermined distance may be equal to at least the longitudinal distance between the proximal end 347 of the needle cover 306 and the proximal end 367 of the skin sensor 331 when the skin sensor 306 is in its proximal position relative to the needle cover 306.

[0191] It will be appreciated that in some embodiments, the predetermined distance may be less than the longitudinal distance between the proximal end 347 of the needle cover 306 and the proximal end 367 of the skin sensor 331 when the skin sensor 306 is in its proximal position relative to the needle cover 306.

[0192] The predetermined distance may be dependent on a number of factors. One of the factors that influences the predetermined distance may be the combined stiffness of the arm 344 of the needle cover 306 and the reinforcing member 364 of the skin sensor 331. That is, the more stiff the arm 344 and / or the reinforcing member 364, the larger the predetermined distance may be.For example, in embodiments in which the arm 344 of the needle cover 306 is particularly stiff, especially when compared to the reinforcing member 367 of the skin sensor 331, the predetermined distance may be larger than the longitudinal distance between the proximal end 347 of the needle cover 306 and the proximal end 367 of the skin sensor 331 when the skin sensor 306 is in its proximal position relative to the needle cover 306. In some embodiments, the proximal end of the reinforcing member 364 may be located longitudinally distally of the apex 375 of the catch 371 before the projection 348 disengages from the catch 371.

[0193] In embodiments in which the reinforcing member 367 of the skin sensor 331 is particularly stiff, especially when compared to the arm 344 of the needle cover 306, the predetermined distance may be less than the longitudinal distance between the proximal end 347 of the needle cover 306 and the proximal end 367 of the skin sensor 331 when the skin sensor 306 is in its proximal position relative to the needle cover 306.

[0194] The unlatching force acting on the arm 344 of the needle cover 306 and the reinforcing member 364 of the skin sensor 331 causes the arm 344 and reinforcing member 364 to bend inwards. The unlatching force provided by the needle cover biasing member 311 in the longitudinal direction is transformed into a perpendicularly acting force by the interaction of the surfaces of the catch 371 and the projection 348. The further proximal the unlatching force acts on the reinforcing member 364 of the skin sensor 331 , the less the reinforcing member 364 is able to resist bending.

[0195] Thus, the stiffness of the arm 344 of the needle cover 306 and the reinforcing member 364 of the skin sensor 331 can be selected to provide disengagement of the projection 348 from the catch 371 at a specific predetermined distance.

[0196] Thus, if the medicament delivery device 300 is accidentally partially lifted from the injection site, the retaining mechanism 335 does not release immediately.

[0197] Advantageously, this means that the operator can reapply the pressure to the medicament delivery device 300 and injection site without having to overcome the additional force of the needle cover biasing member 311 as the force of the needlecover biasing member 311 is still being transferred to the housing 301 by the proximal ends 347, 367 of the arm 344 and reinforcing member 364 of the needle cover 306 and skin sensor 331 , respectively.

[0198] Referring now to Fig. 6F, once the medicament delivery device 300 is removed from the injection site, the compressive forces on the needle cover biasing member 311 and the skin sensor biasing member 332 are removed. In the case shown in Fig. 6F, the medicament delivery device 300 may have been deliberately removed or accidentally removed by more than the predetermined distance.

[0199] Previously, due to the reinforcing member 364 holding the projection 348 in engagement with the catch 371 , the needle cover 306 was prevented from moving distally. However, there is no longer a compressive force acting on the skin sensor 331. Therefore, the skin sensor biasing member 332 is able to extend. Thus, the skin sensor 332 may be moved into its distal position relative to the needle cover 306 under the force of the skin sensor biasing member 332.

[0200] When the skin sensor 331 is in its distal position relative to the needle cover 306, the proximal end 367 of the reinforcing member 364 of the skin sensor 331 is moved distally relative to the proximal end 347 of the arm 344 of the needle cover 306. That is, the proximal end 367 of the reinforcing member 364 of the skin sensor 331 is located distally relative to the deflectable proximal end 347 of the arm 344 of the needle cover 306. Thus, the skin sensor 331 may no longer be able to prevent the inward deflection of the projection 348 and proximal end 347 of the arm 344 under the distally acting force of the needle cover biasing member 311.

[0201] Due to the inclined engaging surface 351 of the projection 348, the distally acting force of the needle cover biasing member 311 may cause the engaging surface 351 of the projection 348 to slide against the catch 371. As a result, when the needle cover 306 is in the retracted position and the skin sensor 331 is in the proximal position relative to the needle cover 306, the proximal end 347 of the arm 344 may be deflected inwards. The needle cover biasing member 311 may then bias the needle cover 306 back towards the extended position.Referring briefly to Fig. 6G, the medicament delivery device 300 is shown once the needle cover biasing member 311 has returned the needle cover 306 to the extended position and the projection 348 has moved distally past, or to the distal end of, the ramped portion 373a of the inner surface 373 of the housing 301. The skin sensor 331 is in its distal position relative to the needle cover 306. The distal position of the skin sensor 331 may be limited by engagement of the skin sensor retaining element 356 of the needle cover 306 with the proximal end of the slot 368 of the skin sensor 331 , as shown in Fig. 5.

[0202] In some embodiments, the first engaging surface 351 may be inclined in the range of about 45 degrees to about 55 degrees relative to the longitudinal axis X’ of the retaining mechanism 335. The inclination of the first engaging surface 351 within this range has been found to provide a good balance between sensitivity of the projection 348 and catch 371 to release and the increase in activation force. The proximally facing surface 374 of the recess 372 that forms the catch may have the same angle as the first engaging surface 351 of the projection 348 to optimise the friction between the two components.

[0203] It has been found that the reducing the angle of the first engaging surface 351 of the projection 348 and the proximally facing surface 374 of the catch 371 increases the component of the needle cover biasing member 311 force that acts to flex the arm 344 of the needle cover 306 and the reinforcing member 364 of the skin sensor 331. Thus, by reducing the angle of the first engaging surface 351 of the projection 348, the stiffness requirement of the arm 344 of the needle cover 306 and / or the reinforcing member 364 of the skin sensor 331 is increased. The increase in the stiffness of these two components means a larger force is required to bend them, which results in a higher the activation force to engage the projection 348 of the needle cover 306 in the catch 371 during operation.

[0204] Furthermore, the effect of reducing the angle of the first engaging surface 351 of the projection 348 and the proximally facing surface 374 of the catch 371 is that the design is less sensitive to the coefficient of friction between the two components such that the risk of the needle cover 306 not unlatching is reduced.In some embodiments, the additional force required by an operator of the medicament delivery device 300 to engage the projection 348 with the catch 371 may be in the range of about 0.3 N to about 3 N. In some embodiments, the additional force required by an operator of the medicament delivery device 300 to engage the projection 348 with the catch 371 may be in the range of about 1.4 N to about 2.1 N. The additional force may be the additional force required to engage the latch during activation in addition to the force required to overcome / compress the needle cover biasing member 311 and the skin sensor biasing member 332.

[0205] The skin sensor biasing member 332 may have a hold force when the skin sensor 331 is in its proximal position when the needle cover 306 is in its retracted position, i.e. when the skin sensor biasing member 332 is at maximum compression, of about 1.5 N. In some embodiments, the hold force may be in the range of about 1 N to about 3 N.

[0206] The needle cover biasing member 311 may have a biasing force when the needle cover is in its retracted position, i.e. when the needle cover biasing member 331 is at maximum compression, of about 6.8 N. Thus, when the force of the needle cover biasing member 311 is transferred to the housing 301 when the projection 348 engages the catch 371 , the hold force of the medicament delivery device 300 may be reduced by about 5.3 N. In some embodiments, the reduction in hold force may be in the range of about 4 N to about 7 N.

[0207] In some embodiments, the arm 344 of the needle cover 306 may have a stiffness of about 0.4 N / mm. In some embodiments, the reinforcing arm 364 of the skin sensor 331 may have a stiffness in the range of about 1.3 N / mm to about 2.0 N / mm.

[0208] The medicament delivery device 300 may further comprise a needle cover lock 391, shown schematically in Fig. 6G. The needle cover lock 391 may be configured to prevent proximal movement of the needle cover 306 once the needle cover 306 is in the extended position post-use.Although described previously in detail, a brief description of the method of preparing a medicament delivery device 300 for use will be described hereinafter. The method comprises moving a skin sensor 331 proximally from a distal position to a proximal position against the force of a skin sensor biasing member 332. The method further comprises moving the skin sensor 332 and a needle cover 306 proximally from an extended position to a retracted position within a housing 301. The method further comprises engaging a projection 348 on an arm 344 of the needle cover 306 with a catch 371 located in the housing 301 and maintaining the projection 348 in engagement with the catch 371 with a reinforcing member 364 of the skin sensor 331. Engaging the needle cover 306 with the housing 301 transfers the force of the needle cover biasing member 311 to the housing 301.

[0209] In addition, although described previously in detail, a brief description of the method of locking a medicament delivery device 300 after use will be described hereinafter. The method comprises removing the medicament delivery device 300 from an injection site and moving the skin sensor 331 distally from a proximal position to a distal position under the force of a skin sensor biasing member 332. The method further comprises disengaging a projection 348 of a needle cover 306 from a catch 371 located in a housing 301 , and moving the needle cover 306 in the distal direction from a retracted position to an extended position, under the biasing force of a needle cover biasing member 311. The method further comprising engaging a locking mechanism 391 to prevent proximal movement of the needle cover 306.

[0210] The features described and / or contemplated in relation to the medicament delivery device 300 may be incorporated in another medicament delivery device., for example, a medicament delivery device having a different mechanism for dispensing medicament to that described in relation to the medicament delivery device 100, and / or a medicament delivery device which is configured to inject 2ml or less of medicament and / or a medicament delivery device which is configured to inject a medicament having a viscosity of 25cP or less, and / or a medicament delivery device in which the medicament is contained in a cartridge which is initially separated from the needle when the needle cover is in the initial position.It will be appreciated that the embodiments previously described are configured such that the skin sensor 331 is located radially inward of the needle cover 306 and the catch 371 is located on the inner surface 373 of the housing 301.

[0211] However, it will also be appreciated that the present invention may be configured such that the skin sensor 331 is located radially outward of the needle cover 306 and the catch 371 may be located on a central structural element of the housing 301. In such an embodiment, all previous references to inward and outward radially movement would be opposite to those previously described.

[0212] For clarity, an example of such an embodiment of a medicament delivery device 300 is shown in Fig. 7 in its pre-use position. As shown, the skin sensor 331 is located radially outward of the needle cover 306. In the extended position, the needle cover 306 extends from the distal end 303 of the housing 301 and covers a distal end of the needle (not shown in Fig. 7).

[0213] In Fig. 7, the proximal end 367 of the reinforcing member 364 of the skin sensor 331 is located distally of the proximal end 347 of the arm 344 of the needle cover 306. However, it will be appreciated that in an alternative embodiment, the proximal end 367 of the reinforcing member 364 of the skin sensor 331 may be located proximally of the proximal end 347 of the arm 344 of the needle cover 306.

[0214] In the inverted embodiment, the housing 301 may comprise a structural element 395. The structural element 395 may extend longitudinally in a radially inward position of the arm 344 of the needle cover 306. The catch 371 may be located close to a distal end of the structural element 395.

[0215] As with the previously described embodiment, the needle cover biasing member 311 may extend between the distal end of the structural element 395 and the proximally facing surface 345 of the body 341 of the needle cover 306. The skin sensor biasing member 332 may extend between the distally facing surface 343 of the body 341 of the needle cover 306 and the proximally facing surface of the body 361 of the skin sensor 331. It will be appreciated that in this embodiment the needle cover 306 does not require slots 355 to receive the skin sensor 331.It will be appreciated that the remaining features of the needle cover 306 and the skin sensor 331 are similar to those previously described but merely facing in the opposite direction and so a detailed description thereof will be omitted herein.

[0216] In such an embodiment, the needle cover 306 is located behind the skin sensor 331. Therefore, the needle cover 306 is hidden and is inaccessible from the outside by an operator. This may prevent a device being tampered with. In addition, there is no visible gap between the needle cover 306 and the skin sensor 331.

[0217] Referring now to Figs. 8A to 8E, a further embodiment of a medicament delivery device 400 is shown. Figs. 8A to 8E show simplified schematic side cross-sectional views of a further embodiment of a medicament delivery device 400 at various stages of operation of the medicament delivery device 400. To reduce complexity and replication of subject-matter in the drawings, the cross-sections shown in Figs. 8A to 8E show only one lateral half of the distal end of the medicament delivery device 400.

[0218] The features described and / or contemplated in relation to the medicament delivery device 400 may be incorporated into the medicament delivery devices 100, 200 described and / or contemplated above. In the following described embodiment, the features relating to the needle cover 106, 218 and the needle cover biasing member 111 are modified compared to the medicament delivery devices 100, 200 shown in Figs. 2 and 3.

[0219] It will be appreciated that the following modifications may be applied to the medicament delivery device 100 of Fig. 2 and the flat form medicament delivery device 200 of Fig. 3. For example, the skin sensor 331 of the medicament delivery device 300 may be the component identified by reference numeral ‘227’ in Fig. 3.

[0220] The medicament delivery device 400 comprises a housing 401. The housing 401 comprises a proximal end (not shown in Figs. 8A to 8E) and a distal end 403. Themedicament delivery device 400 further comprises a needle 405 and a needle cover 406. The needle cover 406 is axially movable between an extended position, shown in Fig. 8A, and a retracted position, shown in Fig. 8C.

[0221] In the following description the term axially can be understood to be parallel to the main extension of the needle 405 comprising the distal end of the needle 405. Thus, it will be understood that when the present invention in the following description is applied to a medicament delivery device 100 such as that shown in Fig. 2 the axial direction may extend parallel to the longitudinal axis of the medicament delivery device 100, and when the present invention in the following description is applied to a flat form medicament delivery device 200 such as shown in Fig. 3 the axial direction may extend perpendicularly to the longitudinal axis of the flat form medicament delivery device 200 or the direction of movement of the plunger 206. Thus, the terms distally and proximally may also be understood to mean relative to the injection site that than relative to ‘longitudinal ends’ of the body or housing of the flat form medicament delivery device 200.

[0222] In the extended position, the needle cover 406 extends from the distal end 403 of the housing 401 and covers a distal end 407 of the needle 405, as shown in Fig.

[0223] 8A. In the retracted position, the needle cover 406 is located in a proximal position relative to the extended position. In the retracted position, the needle cover 406 is proximally located such that the needle 405 protrudes from a distal end 408 of the needle cover 406. The medicament delivery device 400 also comprises a needle cover biasing member 411. The needle cover biasing member 411 is configured to bias the needle cover axially in the distal direction towards the extended position.

[0224] The medicament delivery device 400 comprises a skin sensor 431. The skin sensor 431 extends from the distal end 403 of the housing 401. The skin sensor 431 is axially movable between a distal position, shown in Fig. 8A, and a proximal position, shown in Fig. 8C. When the skin sensor 431 is in the distal position, the needle cover 406 is free to move axially. When the skin sensor 431 is in the proximal position, the skin sensor 431 limits axial movement of the needle cover 406.Furthermore, the medicament delivery device 400 comprises a skin sensor biasing member 432. The skin sensor biasing member 432 is configured to bias the skin sensor 431 axially in the distal direction towards its distal position.

[0225] The distal end of the skin sensor 431 is located proximally of the distal end of the needle cover 406 when the needle cover is in its extended position.

[0226] The medicament delivery device 400 further comprises a retaining mechanism 435. The retaining mechanism 435 is configured to temporarily retain the needle cover 406 in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member 411 to the housing 401. Thus, the needle cover biasing member 411 is prevented from moving the needle cover 406 distally.

[0227] One advantage of this arrangement is that once the needle cover 406 has been moved to the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member 411 is reduced, if not completely eliminated. This may be particularly advantageous for users that lack the strength to hold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.

[0228] In some embodiments, the retaining mechanism 435 may be configured to transfer substantially the full force of the needle cover biasing member 411 to the housing 401 when the needle cover 406 is in the retracted position and the skin sensor 431 is in the proximal position, as shown in Fig. 8C. When the needle cover 406 is in its retracted position and the skin sensor 431 is in its proximal position relative to the needle cover 406, the distal end of the needle 405 may extend beyond the distal end of the skin sensor 431.

[0229] In some embodiments, the spring rate of the needle cover biasing member 411 may be greater than the spring rate of the skin sensor biasing member 432. In some embodiments, the spring rate of the needle cover biasing member 411 may be the same as the spring rate of the skin sensor biasing member 432. In such embodiments, the initial compressions of the needle cover biasing member 411and the skin sensor biasing member 432 may be different. For example, the needle cover biasing member 411 may have a greater amount of initial compression than the skin sensor biasing member 432.

[0230] It will be appreciated that in some embodiments, the spring rates of the needle cover biasing member 431 and the skin sensor biasing member 432 may be different and the needle cover biasing member 411 and the skin sensor biasing member 432 may have different amounts of initial compression.

[0231] Referring to Fig. 8A, the needle cover 406 may comprise a body portion 441. The body portion 441 of the needle cover 406 may be the distal most portion of the needle cover 406. The body portion 441 of the needle cover 406 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400. The body portion 441 of the needle cover 406 may be configured to prevent access to the needle 405 when the needle cover 406 is in the extended position. This may help to prevent accidental contact with the needle 405.

[0232] The body portion 441 of the needle cover 406 may be annular. That is, the body portion 441 of the needle cover 406 may comprise an aperture 442. The aperture 442 may be located centrally in the body portion 441 of the needle cover 406. The aperture 442 may extend through the full thickness of the body portion 441 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400. The aperture 442 may be configured to allow the needle 405 to extend therethrough when the needle cover 406 is in the retracted position. The body portion 441 may also be referred to as an annular member.

[0233] The body portion 441 of the needle cover 406 may comprise a distal facing surface 443. The distal facing surface 443 may be configured to be placed against an injection site.

[0234] The needle cover 406 may further comprise an arm 444. The arm 444 of the needle cover 406 may extend in the proximal direction. The arm 444 may extend proximally from the body portion 441 of the needle cover 406. That is, the arm 444of the needle cover 406 may extend proximally from a proximal facing surface 445 of the body portion 441 of the needle cover 406. The arm 444 may extend from, or proximate to, the periphery of the body portion 441 of the needle cover 406.

[0235] The arm 444 may be elongate such that the length dimension of the arm 444 is greater than the width and thickness dimensions of the arm 444. The arm 4444 may extend around only a section of the circumference of the body portion 441 of the needle cover 406, for example, but not limited to 10% to 20% of the circumference of the needle cover 406. Therefore, the arm 4444 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400.

[0236] The arm 444 may comprise a proximal end 447 spaced from the body portion 441 of the needle cover 406. The proximal end 447 of the arm 444 may comprise a projection 448. The projection 448 may form a latch 448, as will be explained in more detail hereinafter. The projection 448 may extend radially inwards from the proximal end 447 of the arm 444 of the needle cover 406.

[0237] In some embodiments, the projection 448 may have a first engaging surface 451 and a second engaging surface 452. The first engaging surface 451 of the projection 448 may be generally distally facing. In some embodiments, the first engaging surface 451 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400.

[0238] The second engaging surface 452 of the projection 448 may be generally proximally facing. The second engaging surface 452 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400 when the needle cover 406 is in the extended position, as shown in Fig. 8A.

[0239] In some embodiments, as shown in Fig. 8A, the arm 444 of the needle cover 406 may extend proximally parallel to the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400 when the needle cover 406 is in the extended position. The arm 444 of the needle cover 406 may bedeflectable in a radially outward direction, i.e. away from the central longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400. The arm 444 of the needle cover 406 may be resiliently deflectable such that it returns to its original parallel alignment with the longitudinal axis X’ once the external deflecting force is removed.

[0240] However, it will be appreciated that in an alternative embodiment, a portion of the arm 444 proximate to the proximal end 447 of the arm 444 may be biased radially outwardly.

[0241] Referring briefly to Fig. 9, a schematic cross-sectional side view of the medicament delivery device 400 is shown in its pre-use position where the needle cover 406 is in its extended position and the skin sensor 431 is in its distal position relative to the needle cover 406. Fig. 9 shows an illustration of the medicament delivery device 400 in which a needle cover retaining mechanism 455 is shown.

[0242] In the illustrated embodiment, the needle cover retaining mechanism 455 is located on the needle cover 406. That is, the needle cover retaining mechanism 455 extends from the arm 444 of the needle cover 406. The needle cover retaining mechanism 455 may comprise a generally radially inwardly extending projection 456. The projection 456 of the needle cover retaining mechanism 455 may be configured to abut a proximal facing surface of a structural element 481 of the housing 401 when the needle cover 406 is in the extended position to limit further extension in the distal direction of the needle cover 406 under the biasing force of the needle cover biasing member 411.

[0243] It will be appreciated that in an alternative embodiment, the needle cover retaining mechanism 455 may comprise a projection 456 extending from an component (not shown) of the housing 401 that is configured to engage within a slot in the arm 444 of the needle cover 406 with a stop (not shown) or engage with a projection extending from the arm 444 of the needle cover 406 to limit distal travel of the needle cover 406.In some embodiments, the needle cover 406 may comprise a plurality of arms 444. The plurality of arms 444 may be spaced circumferentially about the body portion 441 of the needle cover 406. The plurality of arms 444 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400. In embodiments where two arms 444 are present, the arms 444 may be located diametrically opposite each other.

[0244] Referring to Fig. 8A, the skin sensor 431 may comprise a body portion 461. The body portion 461 of the skin sensor 431 may be the distal-most portion of the skin sensor 431. The skin sensor 431 may comprise a distal facing surface 462. The distal facing surface 462 may be configured to contact an injection site. The distal facing surface 462 of the skin sensor 431 may contact an injection site when the needle cover 406 has been moved proximally from its extended position to its initial depression position, as shown in Fig. 8B. The body portion 461 of the skin sensor 431 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400.

[0245] The body portion 461 of the skin sensor 431 may be annular. That is, the body portion 461 of the skin sensor 431 may comprise an aperture 463. The aperture 463 may be located centrally in the body portion 461 of the skin sensor 431. The aperture 463 may extend through the full thickness of the body portion 461 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400.

[0246] The skin sensor 431 may be located radially outward of the needle cover 406. Therefore, the body portion 461 of the skin sensor 431 may extend circumferentially around the needle cover 406. Thus, the aperture 463 may be configured to allow the needle cover 406 to extend therethrough when the needle cover 406 is in its extended position. The aperture 463 may also be configured to allow the needle 405 to extend therethrough when the skin sensor 431 is in the proximal position. The aperture 463 of the skin sensor 431 may be configured to receive the body portion 441 of the needle cover 406 when the needle cover 406 is in its initial depression position, as shown in Fig. 8B.It will be appreciated that is some embodiments, the body portion 461 of the skin sensor 431 may not extend circumferentially around the whole of the needle cover 406. That is, the body portion 461 of the skin sensor 431 may extend partially circumferentially around the needle cover 406. In some embodiments, the body portion 461 may be formed by two or more circumferentially extending portions separated circumferentially by a gap.

[0247] The skin sensor 431 may further comprise a reinforcing member 464. The reinforcing member 464 of the skin sensor 431 may extend in the proximal direction. The reinforcing member 464 may extend proximally from the body portion 461 of the skin sensor 431. That is, the reinforcing member 464 of the skin sensor 431 may extend proximally from a proximal facing surface of the body portion 461 of the skin sensor 431.

[0248] The reinforcing member 464 may be elongate such that the length dimension of the reinforcing member 464 is greater than the width and thickness dimensions of the reinforcing member 464. The reinforcing member 464 may extend around only a section of the circumference of the body portion 461 of the skin sensor 431 , for example, but not limited to, 10% to 20% of the circumference of the skin sensor 431. Therefore, the reinforcing member 464 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400.

[0249] The reinforcing member 464 may comprise a proximal end 467 spaced from the body portion 461 of the skin sensor 431. The proximal end 467 of the reinforcing member 464 may be configured to be located at a more proximal axial point within the medicament delivery device 400 than the proximal end 447 of the arm 444 of the needle cover 406 when the skin sensor 431 is in its distal position and the needle cover 406 is in its extended position, as shown in Fig. 8A, as will be described in more detail hereinafter.

[0250] In some embodiments, the length dimension of the skin sensor 431 and the length dimension of the needle cover 406 may be substantially the same, as illustrated in Figs. 8B and 8C. In some embodiments, the length dimension of the reinforcingmember 464 of the skin sensor 431 and the length dimension of the arm 444 of the needle cover 406 may be substantially the same.

[0251] As shown in Figs. 8B and 8C, the length dimension of the skin sensor 431 may be slightly larger than the length dimension of the needle cover 406. That is, the proximal end 467 of the reinforcing member 464 of the skin sensor 431 may be located proximally of the proximal end 447 of the arm 444 of the needle cover 406 when the needle cover 406 is in its initial depression position and the skin sensor 431 is in its distal position, as shown in Fig. 8B, and when the needle cover 406 is in its retracted position and the skin sensor 431 is in its proximal position, as shown in Fig. 8C, also referred to as the latched position.

[0252] Advantageously, the skin sensor 431 having a slightly larger length dimension than the needle cover 406 means that the skin sensor 431 may be able to move further in the distal direction before the needle cover 406 can disengage with the housing 401 to move back towards the extended position, as will be explained in more detail hereinafter. One associated benefit is that partial accidental removal of the medicament delivery device 400 from the injection site will not cause the needle cover 406 to be released from its latched position, as will be explained in more detail hereinafter.

[0253] Referring back to Fig. 8A, the reinforcing member 464 of the skin sensor 431 may comprise a distal portion 464a and a proximal portion 464b. The distal portion 464a may extend from the body portion 461 of the skin sensor 431. The proximal portion 464b of the reinforcing member 464 may extend from a proximal end of the distal portion 464a of the reinforcing member 464. The proximal end 467 of the reinforcing member 464 may be located at the proximal end of the proximal portion 464b of the reinforcing member 464.

[0254] At least a part of the proximal portion 464b of the reinforcing member 464 may have a greater thickness dimension than the distal portion 464a of the reinforcing member 464. That is, the distal portion 464a may be thinner than at least a part of the proximal portion 464b of the reinforcing member 464. Advantageously, thereduced thickness of the distal portion 464a of the reinforcing member 464 enables the reinforcing member 464 to have greater flexibility.

[0255] The proximal portion 464b of the reinforcing member 464 may have an outer surface that extends in the same plane as the outer surface of the distal portion 464a of the reinforcing member 464. The proximal portion 464b of the reinforcing member 464 may have an inner surface that it located radially inward of the inner surface of the distal portion 464a of the reinforcing member 464. The proximal portion 464b of the reinforcing member 464 may be formed by a radially inward extending projection 468. The inner surface of the proximal portion 464b of the reinforcing member 464 may extend parallel to the longitudinal axis X’ of the retaining mechanism 435.

[0256] In some embodiments, the inner surface of the projection 468 may contact an outer surface of the arm 444 of the needle cover 406, when the needle cover 406 has been moved proximally from its extended position. In some embodiments, the inner surface of the projection 468 may contact an outer surface of the arm 444 of the needle cover 406 throughout the use of the medicament delivery device 400 from the initial compression position until the medicament delivery device 400 is completely removed from the injection site.

[0257] However, it will be appreciated that in alternative embodiments, there may exist a gap between the arm 444 of the needle cover 406 and the inner surface of the projection 468 when the needle cover 406 is moved into the initial compression position. In such an embodiment, contact between the outer surface of the arm 444 of the needle cover 406 and the inner surface of the projection 468 of the skin sensor 431 may occur when moving into or out of the latched position and whilst in the latched position, see Figs. 8B, 8D, and 8C respectively.

[0258] Advantageously, the increased thickness of the proximal portion 464b of the reinforcing member 464 may prevent premature release of the needle cover 406 from its retracted position. The increased thickness of the projection 468 reduces the amount of bending of the arm 444 of the needle cover 406 that is possible in the latched position, see Fig. 8C, before the arm 444 of the needle cover 406contacts the projection 468 of the reinforcing member 464 of the skin sensor 431. As a result, the strength of the retaining mechanism 435 is increased.

[0259] In addition, in some embodiments, the thickness of the projection 468 reduces the amount of bending of the arm 444 of the needle cover 406 in the latched position before the reinforcing member 464 is pushed into contact with the inner surface of the housing 401. In such a position, the arm 444 of the needle cover 406 is prevented from bending further in the outwardly radial direction and prevents the needle cover 406 being unlatched from its latched position, i.e. retracted position, shown in Fig. 8C.

[0260] The thickness of the distal portion 464a and the proximal portion 464b of the reinforcing member 464 may be tuned to provide the required thickness to enable the required flexibility of the reinforcing member 464 and the required retention levels for the arm 444 of the needle cover 406, as will be explained in more detail hereinafter.

[0261] The medicament delivery device 400 may further comprise a skin sensor retaining mechanism 469. The skin sensor retaining mechanism 469 may comprise a skin sensor projection 469aa. The skin sensor projection 469a may extend generally radially outwardly from the reinforcing member 464 of the skin sensor 431. The skin sensor retaining mechanism 469 may further comprise a stop element 469b. The stop element 469b may extend from the housing 401. The stop element 469b may extend generally radially inwardly from the distal end 403 of the housing 401.

[0262] The skin sensor projection 469a of the skin sensor 431 may be configured to abut the distal facing surface of the stop element 469b of the housing 401 when the skin sensor 431 is in its distal position to limit further extension in the distal direction of the skin sensor 431 under the biasing force of the skin sensor biasing member 432.

[0263] It will be appreciated that in an alternative embodiment, the skin senor retaining mechanism 469 may comprise a projection extending from the skin sensor 431 or the housing 401 that is configured to engage within a slot (not shown) in the otherof the skin sensor 431 or the housing 401 with a stop (not shown) or engage with a projection in in the other of the skin sensor 431 or the housing 401 to limit distal travel of the skin sensor 431.

[0264] The skin sensor 431 may comprise a plurality of reinforcing members 464. The plurality of reinforcing members 464 may be spaced circumferentially about the body portion 461 of the skin sensor 431. The plurality of reinforcing members 464 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 435 of the medicament delivery device 400. In some embodiments where two reinforcing members 464 are present, the reinforcing members 464 may be located diametrically opposite each other.

[0265] As shown in Figs. 8A to 8E, the housing 401 may comprise a catch 471. The catch 471 may be configured to cooperate with the projection 448 of the needle cover 406 when the needle cover 406 is in its retracted position and the skin sensor 431 is in its proximal position, as shown in Fig. 8C, and also referred to as the latched position.

[0266] The catch 471 may be located on a structural element 472 of the housing 401. The structural element 472 of the housing 401 may be located radially inward of the arm 444 of the needle cover 406. That is, the structural element 472 may be located closer to the longitudinal axis X’ of the retaining mechanism 435 than the arm 444 of the needle cover 406.

[0267] The structural element 472 may comprise a first part 472a and a second part 472b. The first part 472a may extend from an inner surface 473 of the housing 401. That is, the first part 472a may extend from the inner surface 473 of the main outer body of the housing 401. The first part 472a may extend generally inwardly in a radial direction. The first part 472a may extend perpendicularly to the longitudinal axis X’ of the retaining mechanism 435.

[0268] The second part 472b may extend from a free end of the first part 472a. The second part 472b may extend perpendicularly to the first part 472a. That is, the second part 472b may extend parallel to the longitudinal axis X’ of the retainingmechanism 435. The second part 472b may extend from the free end of the first part 472a in the distal direction.

[0269] The catch 471 may be located on a distal free end of the second part 472b of the structural element 472. The catch 471 may be formed by a protrusion 474. The protrusion may extend generally radially outwards. The catch 471 may be formed by a generally proximally facing surface 475 of the protrusion 474. The proximally facing surface 475 may extend in a plane that is inclined relative to the longitudinal axis X’ of the retaining mechanism 435. The inclined plane of the proximally facing surface 475 may extend such that its distal end is further radially outward compared to its proximal end. The catch 471 may be profiled to match the surface profile of the first engaging surface 451 of the projection 448 of the needle cover 406. That is, the geometry of the proximally facing surface 475 may be profiled to match the shape of the projection 448 of the needle cover 406.

[0270] The protrusion 474 may further comprise a ramped portion 476. The ramped portion 476 may form a generally distally facing surface of the projection 475. The ramped portion 476 of the protrusion 474 may extend in a plane that is inclined relative to the longitudinal axisX’ of the retaining mechanism 435. The inclined plane of the distally facing surface 476 may extend such that its distal end is further radially inward compared to its proximal end. That is, the ramped portion 476 may be inclined in the opposite direction to the proximally facing surface 475. Thus, the proximally facing surface 475 and the distally facing surface 476 of the protrusion 474 of the catch 471 may form a generally triangular shape. The distally facing surface 476 of the catch 471 may be configured to contact the second engaging surface 452 of the needle cover 406 to bias the proximal end 447 of the arm 444 radially outwards during proximal movement of the needle cover 406 to enable the projection 448 of the needle cover 406 to pass the catch 471 and move into the latched position.

[0271] The retaining mechanism 435 may comprise the proximally extending arm 444 of the needle cover 406, the projection 448 located on the proximal end 447 of the arm 444, and the catch 471 located on the structural element 472 of the housing401. The projection 448 may be configured to engage the catch 471 when the needle cover 406 is moved into its retracted position, as shown in Fig. 8C.

[0272] In some embodiments, the retaining mechanism 435 may comprise the proximally extending reinforcing member 464 of the skin sensor 431. The reinforcing member 464 may be configured to prevent the projection 448 from disengaging from the catch 471 when the needle cover 406 is held in the retracted position and the skin sensor 431 is held in the proximal position.

[0273] Referring to Fig. 8A, the needle cover biasing member 411 is extended such that the needle cover 406 is located in its extended position. The needle cover biasing member 411 may act on a proximally facing surface 445 of the body portion 441 of the needle cover 406 and on a structural element 481 of the housing 401. The needle cover biasing member 411 may be located radially inwardly of the arm 444 of the needle cover 406.

[0274] In Fig. 8A, the skin sensor biasing member 432 is extended such that the skin sensor 431 is in its distal position. That is, the skin sensor biasing member 432 biases the skin sensor 431 distally relative to the housing 401. The skin sensor biasing member 432 may act on a proximal end 467 of the reinforcing member 464 of the skin sensor 431 and on a distal face of the structural member 472 of the housing 401. That is, the skin sensor biasing member 432 may act on a distal surface of the first part 472a of the structural member 472 of the housing 401. Thus, the skin sensor biasing member 432 may be located proximally of the skin sensor 431 and located at the same radial distance from the longitudinal axis X’ of the retaining mechanism 435 as the reinforcing member 464 of the skin sensor 431.

[0275] Briefly referring to Fig. 9, in some embodiments, the skin sensor biasing member 432 may be mounted differently such that it is not mounted on a deflectable end of the skin sensor 431.

[0276] For example, the housing 401 may comprise a structural element 477. The structural element 477 may extend generally radially inwards from an inner surfaceof the housing 401. A proximal end of the skin sensor biasing member 432 may be mounted to a distally facing surface of the structural element 477.

[0277] The skin sensor 432 may comprise a skin sensor projection 469a. The skin sensor projection 469a may extend generally radially outwardly from the reinforcing member 464 of the skin sensor 431. The skin sensor projection 469a may be located distally of the structural element 477 throughout operation of the device 400. A distal end of the skin sensor biasing member 432 may be mounted to a proximally facing surface of the skin sensor projection 469a.

[0278] Referring to Fig. 8B, upon placement of the medicament delivery device 400 against an injection site, downward pressure on the medicament delivery device 400 may cause the needle cover biasing member 411 to compress. Thus, the needle cover 406 may be moved from its distal position, as shown in Fig. 8A, towards its proximal position, shown in Fig. 8C, against the biasing force of the needle cover biasing member 411.

[0279] The needle cover 406 may be moved against the biasing force of the needle cover biasing member 411 until it reaches its initial compression position, as shown in Fig. 8B. In the initial compression position, the distal end of the needle cover 406 is in the same plane extending perpendicularly to the longitudinal axis X’ of the retaining mechanism 435 as the distal end of the skin sensor 431. Thus, the distal end of the needle cover 406 and the skin sensor 331 may be in contact with the injection site. The needle cover biasing member 411 may have been initially compressed. The skin sensor 431 may still be in its distal position and the skin sensor biasing member 432 may have not been compressed when compared to its pre-use condition.

[0280] Therefore, the needle cover 406 may be moved into its initial depression position before the skin sensor 431 is moved from its distal position. As shown in Fig. 8B, the proximal end 467 of the skin sensor 431 may be located slightly proximally of the proximal end 447 of the needle cover 406. In some embodiments, the projection 468 of the reinforcing member 464 may contact the outer surface of the arm 444 of the needle cover 406 in the initial compression position.Referring now to Fig. 8C, the needle cover 406 has been moved proximally from the initial depression position towards its retracted position against the biasing force of the needle cover biasing member 411. The skin sensor 431 has been moved proximally from its distal position to its proximal position against the biasing force of the skin sensor biasing member 432. The skin sensor 431 may move together with the needle cover 406 such that the proximal ends 447, 467 of the needle cover 406 and the skin sensor 431 remain in the same positions relative to each other in the longitudinal direction. As shown in Fig. 8C, the retaining mechanism 435 has reached its latched position with the needle cover 406 is in retracted position and the skin sensor 431 in its proximal position.

[0281] As the needle cover 406 and skin sensor 431 are moved proximally, the projection 448 of the needle cover 406 engages the ramped portion 476 of the structural element 472 of the housing 401. Engagement between the projection 448 of the needle cover 406 and the ramped portion 476 of the structural element 472 of the housing 401 may cause the proximal end 447 of the arm 444 to be biased radially outwards. Bending of the arm 444 radially outwards causes the proximal end 467 of the reinforcing member 464 to move radially outwards.

[0282] The further the needle cover 406 and the skin sensor 431 are moved in the proximal direction, the further the ramped portion 476 of the structural element 472 of the housing 401 extends radially away from the longitudinal axis X’ of the retaining mechanism 435. Therefore, the further the needle cover 406 and the skin sensor 431 are moved in the proximal direction, the further the projection 448 on the proximal end 447 of the arm 444 of the needle cover 406 and the proximal end 467 of the reinforcing member 464 are moved radially outward away from the longitudinal axis X’ of the retaining mechanism 435.

[0283] As a result, the operator of the medicament delivery device 400 may feel an increase in the force required to depress the medicament delivery device 400 against an injection site. The increase in force is required to overcome friction and the resistance to bending of the arm 444 of the needle cover 406 and the reinforcing member 464 of the skin sensor 431. It will be appreciated that theincline and length of the ramped portion 476 of the catch 471 of the housing 401 as well as the length, width, and thickness of the arm 444 and reinforcing member 464, and the materials that the needle cover 406 and skin sensor 431 are formed from may be tailored to provide a minimal increase in the force required to depress the medicament delivery device 400 against an injection site whilst providing the benefits of the retaining function described herein.

[0284] When the needle cover 406 is moved sufficiently in the proximal direction, the needle cover 406 may reach its retracted position, as shown in Fig. 8C. In this position, the projection 448 may be located on the catch 471. In this position, the projection 448 may be configured to engage the catch 471. That is, the first engaging surface 451 of the projection 448 may contact the proximally facing surface 474 of the catch 471. The reinforcing member 464 of the skin sensor 431 may prevent the projection 448 disengaging from the catch 471 when the skin sensor 431 is held in its proximal position relative to the needle cover 406. This may be achieved by the operator holding the medicament delivery device 400 depressed against the injection site. Thus, the biasing force of the needle cover biasing member 411 may be transferred to the housing 401 of the medicament delivery device 400. This may reduce the hold force required by the operator during operation of the medicament delivery device 400.

[0285] For example, whilst the projection 448 is located on the catch 471 , the needle cover biasing member 411 may exert a force on the needle cover 406 in an attempt to return the needle cover 406 to its extended position. However, the projection 448 may abut against the proximally facing surface 474 of the catch 471 such that the force of the needle cover biasing member 411 may be transferred to the housing 401.

[0286] Due to the inclined engaging surface 451 of the projection 448, the distally acting force of the needle cover biasing member 411 may cause the engaging surface 451 of the projection 448 to slide against the catch 471 , which may result in the proximal end 447 of the arm 444 deflecting outwards. Sufficient distal movement of the needle cover 406 may result in the projection 448 disengaging with the catch 471.However, the projection 468 of the reinforcing member 464 of the skin sensor 431 may abut the outer surface of the arm 444 of the needle cover 406. Thus, the skin sensor 431 may be configured to prevent, or at least resist, the outward deflection of the proximal end 447 of the arm 444 under the distally acting force of the needle cover biasing member 411. In some embodiments, the reinforcing member 464 may be located close enough to the main body of the housing 401 such that the reinforcing member 464 may be additionally reinforced by the housing 401 to prevent the needle cover 406 moving distally from its retracted position when the reinforcing member 464 is in its proximal position.

[0287] In some embodiments, the reinforcing member 464 of the skin sensor 431 may be stiffer than the arm 444 of the needle cover 406. Thus, as the projection 448 cannot be disengaged with the catch 471 when the needle cover 406 is in the retracted position and the skin sensor 431 is in the proximal position relative to the needle cover 406, due to an operator holding the medicament delivery device 400 against an injection site, the biasing force of the needle cover biasing member 411 may be transferred to the housing 401.

[0288] In some embodiments, the resilience of the reinforcing arm 464 may assist in moving the projection 448 of the arm 444 into its latching position on the catch 471. That is, when the first engaging surface 451 of the projection 448 passes the apex 475 of the catch 471 , the stiffness of the reinforcing member 464 may contribute to biasing the projection 448 fully onto the catch 471. This may reduce the force required by the operator to move the needle cover 406 into its retracted latched position at the very end of the depression stroke of the medicament delivery device 400.

[0289] Referring now to Fig. 8D, once the medicament delivery device 400 is removed from the injection site, the compressive forces on the needle cover biasing member 411 and the skin sensor biasing member 432 may be removed.

[0290] In the case of accidental partial removal of the medicament delivery device 400 from the injection site, the skin sensor 431 may be urged distally from its proximalposition towards its distal position by the skin sensor biasing member 432.

[0291] However, due to the proximal end 467 of the reinforcing member 464 being located in a slightly more proximal position than the proximal end 447 of the arm 444 in the latching position, the skin sensor 431 may move distally relative to the needle cover 406 by a predetermined distance before the projection 448 may disengage the catch 471.

[0292] In some embodiments, the predetermined distance may be equal to at least the longitudinal distance between the proximal end 447 of the needle cover 406 and the proximal end 467 of the skin sensor 431 when the skin sensor 406 is in its proximal position relative to the needle cover 406. The predetermined distance may be equal to at least the longitudinal distance between the proximal end 467 of the reinforcing member 464 of the skin sensor 431 and the apex of the catch 471 when the skin sensor 431 is in its proximal position. It will be appreciated that in some embodiments, the predetermined distance may be less than the longitudinal distance between the proximal end 467 of the reinforcing member 464 of the skin sensor 431 and the apex of the catch 471 when the skin sensor 431 is in its proximal position.

[0293] The predetermined distance may be dependent on a number of factors. One of the factors that influences the predetermined distance may be the combined stiffness of the arm 444 of the needle cover 406 and the reinforcing member 464 of the skin sensor 431. That is, the more stiff the arm 444 and / or the reinforcing member 464, the larger the predetermined distance may be.

[0294] The unlatching force acting on the arm 444 of the needle cover 406 and the reinforcing member 464 of the skin sensor 431 causes the arm 444 and reinforcing member 464 to bend outwards. The unlatching force provided by the needle cover biasing member 411 in the longitudinal direction is transformed into a perpendicularly acting force by the interaction of the surfaces of the catch 471 and the projection 448. The further proximal the unlatching force acts on the reinforcing member 464 of the skin sensor 431 , the less the reinforcing member 464 is able to resist bending.Thus, the stiffness of the arm 444 of the needle cover 406 and the reinforcing member 464 of the skin sensor 431 can be selected to provide disengagement of the projection 448 from the catch 471 at a specific predetermined distance.

[0295] In some embodiments, the arm 444 of the needle cover 406 may be sufficiently stiff such that the proximal end 467 of the reinforcing member 464 of the skin sensor 431 may be located distally of the apex of the catch 471 before the projection 448 of the arm 444 of the needle cover 406 can disengage the catch 471.

[0296] Thus, if the medicament delivery device 400 is accidentally partially lifted from the injection site, the retaining mechanism 435 does not release immediately.

[0297] Advantageously, this means that the operator can reapply the pressure to the medicament delivery device 400 and the injection site without having to overcome the additional force of the needle cover biasing member 411 as the force of the needle cover biasing member 411 is still being transferred to the housing 401 by the proximal ends 447, 467 of the arm 444 and reinforcing member 464 of the needle cover 406 and skin sensor 431 , respectively.

[0298] Referring to Fig. 8E, once the medicament delivery device 400 is removed from the injection site, the compressive forces on the needle cover biasing member 411 and the skin sensor biasing member 432 are removed. In the case shown in Fig.

[0299] 8E, the medicament delivery device 400 may have been deliberately removed or accidentally removed by more than the predetermined distance.

[0300] Previously, due to the reinforcing member 464 holding the projection 448 in engagement with the catch 471, the needle cover 406 was prevented from moving distally. However, there is no longer a compressive force acting on the skin sensor 431. Therefore, the skin sensor biasing member 432 is able to extend. Thus, the skin sensor 431 may be moved into its distal position under the force of the skin sensor biasing member 432.

[0301] When the skin sensor 431 is moved distally from its proximal position by a distance greater than the predetermined distance, the proximal end 467 of thereinforcing member 464 of the skin sensor 431 is moved distally relative to the proximal end 447 of the arm 444 of the needle cover 406. That is, the proximal end 467 of the reinforcing member 464 of the skin sensor 431 is located distally relative to the deflectable proximal end 447 of the arm 444 of the needle cover 406. Thus, the skin sensor 431 may no longer be able to prevent outward deflection of the projection 448 and proximal end 447 of the arm 444 under the distally acting force of the needle cover biasing member 411 and incline of the catch 471.

[0302] Due to the inclined engaging surface 451 of the projection 448, the distally acting force of the needle cover biasing member 411 may cause the engaging surface 451 of the projection 448 to slide against the catch 471. As a result, when the needle cover 406 is in the retracted position and the skin sensor 431 is moved distally beyond the predetermined distance, the proximal end 447 of the arm 444 may be deflected outwards. The needle cover biasing member 411 may then bias the needle cover 406 back towards the extended position.

[0303] Referring briefly to Fig. 8E, the medicament delivery device 400 is shown once the needle cover biasing member 411 has returned the needle cover 406 to the extended position and the skin sensor 411 is in its distal position.

[0304] The medicament delivery device 400 may further comprise a needle cover lock 491 , shown schematically in Fig. 8E. The needle cover lock 491 may be configured to prevent proximal movement of the needle cover 406 once the needle cover 406 is in the extended position post-use.

[0305] Although described previously in detail, a brief description of the method of preparing a medicament delivery device 400 for use will be described hereinafter. The method comprises moving a needle cover 406 from its extended position to an initial compression position against the force of a needle cover biasing member 411. The method further comprises moving the needle cover 406 and a skin sensor 431 from the initial compression position to their respective retracted and proximal positions against the force of the needle cover biasing member 411 and a skin sensor biasing member 432. The method further comprises engaging aprojection 448 on an arm 444 of the needle cover 406 with a catch 471 located on a structural element 473 of the housing 401 that is located radially inwardly of the needle cover 406. The method further comprises maintaining the projection 448 in engagement with the catch 471 with a reinforcing member 464 of the skin sensor 431 in a latched position, and transferring the force of the needle cover biasing member to the housing when the needle cover is in the latched position.

[0306] In addition, although described previously in detail, a brief description of the method of extending a needle cover 406 of a medicament delivery device 400 after use will be described hereinafter. The method comprises removing the medicament delivery device 400 from an injection site and moving the skin sensor 431 distally from a proximal position to a distal position under the force of a skin sensor biasing member 432. The method further comprises disengaging a projection 448 of a needle cover 406 from a catch 471 located in a housing 401 , and moving the needle cover 406 in the distal direction from a retracted position to an extended position, under the biasing force of a needle cover biasing member 411. The method further comprising engaging a locking mechanism 481 to prevent proximal movement of the needle cover 406.

[0307] The features described and / or contemplated in relation to the medicament delivery device 400 may be incorporated in another medicament delivery device., for example, a medicament delivery device having a different mechanism for dispensing medicament to that described in relation to the medicament delivery device 100, and / or a medicament delivery device which is configured to inject 2ml or less of medicament and / or a medicament delivery device which is configured to inject a medicament having a viscosity of 25cP or less, and / or a medicament delivery device in which the medicament is contained in a cartridge which is initially separated from the needle when the needle cover is in the initial position.

[0308] It will be appreciated that the embodiments previously described are configured such that the needle cover 406 is located radially inwards of the skin sensor 431 and the catch 471 is located on a central structural element 472 of the housing 401. However, it will also be appreciated that the present invention may be configured such that the skin sensor 431 is located radially inward of the needlecover 406 and the catch 471 may be located on an inner surface of the outer wall of the housing 401. In such embodiments, all previous references to inward and outward radial movement and inner and outer surfaces would be opposite to those previously described.

[0309] Referring now to Figs. 10A to 10F, a further embodiment of a medicament delivery device 500 is shown. Figs. 10A to 10F show simplified schematic side cross-sectional views of a medicament delivery device 500 at various stages of operation of the medicament delivery device 500.

[0310] The features described and / or contemplated in relation to the medicament delivery device 500 may be incorporated into the medicament delivery devices 100, 200 described and / or contemplated above. In the following described embodiment, the features relating to the needle cover 106, 218 and the needle cover biasing member 111 are modified compared to the medicament delivery devices 100, 200 shown in Figs. 2 and 3.

[0311] It will be appreciated that the following modifications may be applied to the medicament delivery device 100 of Fig. 2 and the flat form medicament delivery device 200 of Fig. 3. For example, the skin sensor 331 of the medicament delivery device 300 may be the component identified by reference numeral ‘227’ in Fig. 3.

[0312] The medicament delivery device 500 comprises a housing 501. The housing 501 comprises a proximal end (not shown in Figs. 10A to 10F) and a distal end 503. The medicament delivery device 500 further comprises a needle 505 and a needle cover 506. The needle cover 506 is axially movable between an extended position, shown in Fig. 10A, and a retracted position, shown in Fig. 10C.

[0313] In the following description the term axially can be understood to be parallel to the main extension of the needle 505 comprising the distal end of the needle 505. Thus, it will be understood that when the present invention in the following description is applied to a medicament delivery device 100 such as that shown inFig. 2, the axial direction may extend parallel to the longitudinal axis of the medicament delivery device 100, and when the present invention in the following description is applied to a flat form medicament delivery device 200 such as shown in Fig. 3, the axial direction mat extend perpendicularly to the longitudinal axis of the flat form medicament delivery device 200 or the direction of movement of the plunger 206. Thus, the terms distally and proximally may also be understood to mean relative to the injection site rather than relative to ‘longitudinal ends’ of the body or housing of the flat form medicament delivery device 200.

[0314] In the extended position, the needle cover 506 extends from the distal end 503 of the housing 501 and covers a distal end 507 of the needle 505, as shown in Fig.

[0315] 10A. In the retracted position, the needle cover 506 is located in a proximal position relative to the extended position. In the retracted position, the needle cover 506 is proximally located such that the needle 505 protrudes from a distal end 508 of the needle cover 506. The medicament delivery device 500 also comprises a needle cover biasing member 511. The needle cover biasing member 511 is configured to bias the needle cover 506 axially in the distal direction towards the extended position.

[0316] The medicament delivery device 500 comprises a skin sensor 531. The skin sensor 531 extends from the distal end 503 of the housing 501. The skin sensor 531 is axially movable between a distal position, shown in Fig. 10A, and a proximal position, shown in Fig. 10C. When the skin sensor 531 is in the distal position, the needle cover 506 is free to move axially.

[0317] Furthermore, the medicament delivery device 500 comprises a skin sensor biasing member 532. The skin sensor biasing member 532 is configured to bias the skin sensor 531 axially towards its distal position.

[0318] The medicament delivery device 500 further comprises a retaining mechanism 535. The retaining mechanism 535 comprises a collar 536. The collar 536 is axially fixed within the housing 501. The collar 536 is configured to be moveable between a disengaged position and an engaged position. The collar 536 is in the disengaged position when the skin sensor 531 is in its distal position. The collar536 is in the engaged position when the skin sensor 531 is in its proximal position and the needle cover 506 is in its retracted position. In the engaged position the collar 536 is configured to temporarily retain the needle cover 506 in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member 511 to the housing 501 such that the needle cover biasing member 511 is prevented from moving the needle cover 506 distally.

[0319] One advantage of this arrangement is that once the needle cover 506 has been moved to the retracted position, the holding force required to overcome the distally acting force of the needle cover biasing member 511 is reduced, if not completely eliminated. This may be particularly advantageous for users that lack the strength to hold a medicament delivery device against the force of a needle cover biasing member for longer periods of time.

[0320] The distal end of the skin sensor 531 may be located proximally of the distal end of the needle cover 506 when the needle cover 506 is in its extended position and the skin sensor 531 is in its distal position, as shown in Fig. 10A. When the needle cover 506 is in its retracted position and the skin sensor 531 is in its proximal position relative to the needle cover 506, the distal end of the needle 505 may extend beyond the distal end of the skin sensor 531.

[0321] In some embodiments, the retaining mechanism 535 may be configured to transfer substantially the full force of the needle cover biasing member 511 to the housing 501 when the collar 536 is in the engaged position, as shown in Fig. 10C.

[0322] In some embodiments, the spring rate of the needle cover biasing member 511 may be greater than the spring rate of the skin sensor biasing member 532. In some embodiments, the spring rate of the needle cover biasing member 511 may be the same as the spring rate of the skin sensor biasing member 532. In such embodiments, the initial compressions of the needle cover biasing member 511 and the skin sensor biasing member 532 may be different. For example, the needle cover biasing member 511 may have a greater amount of initial compression than the skin sensor biasing member 532.It will be appreciated that in some embodiments, the spring rates of the needle cover biasing member 531 and the skin sensor biasing member 532 may be different and the needle cover biasing member 511 and skin sensor biasing member may have different amounts of initial compression.

[0323] Referring to Fig. 10A, the needle cover 506 may comprise a body portion 541. The body portion 541 of the needle cover 506 may be the distal most portion of the needle cover 506. The body portion 541 of the needle cover 506 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. The body portion 541 of the needle cover 506 may be configured to prevent access to the needle 506 when the needle cover 506 is in the extended position. This may help to prevent accidental contact with the needle 505.

[0324] The body portion 541 of the needle cover 506 may be annular. That is, the body portion 541 of the needle cover 506 may comprise an aperture 542. The aperture 542 may be located centrally in the body portion 541 of the needle cover 506. The aperture 542 may extend through the full thickness of the body portion 541 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. The aperture 542 may be configured to allow the needle 505 to extend therethrough when the needle cover 506 is in the retracted position. The body portion 541 may also be referred to as an annular member.

[0325] The body portion 541 of the needle cover 506 may comprise a distal facing surface 543. The distal facing surface 543 may be configured to be placed against an injection site.

[0326] The needle cover 506 may further comprise an arm 544. The arm 544 of the needle cover 5065 may extend in the proximal direction. The arm 544 may extend proximally from the body portion 541 of the needle cover 506. That is, the arm 544 of the needle cover 506 may extend proximally from a proximal facing surface 545 of the body portion 541 of the needle cover 506. The arm 544 may extend from, or proximate to, the periphery of the body portion 541 of the needle cover 506.The arm 544 may be elongate such that the length dimension of the arm 544 is greater than the width and thickness dimensions of the arm 544. The arm 544 may extend around only a section of the circumference of the body portion 541 of the needle cover 506, for example, but not limited to 10% to 20% of the circumference of the needle cover 506. Therefore, the arm 544 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500.

[0327] The arm 544 may comprise a proximal end 547 spaced from the body portion 541 of the needle cover 506.

[0328] In some embodiments, as shown in Fig. 10A, the arm 544 of the needle cover 506 may extend proximally parallel to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500 when the needle cover 506 is in the extended position.

[0329] Referring briefly now to Fig. 10F, embodiments of component mechanisms for retaining the needle cover 506 and the skin sensor 531 within the medicament delivery device 500 are shown.

[0330] In the illustrated embodiment, a needle cover retaining element 555 is shown. The needle cover retaining mechanism 555 is located on the needle cover 506. That is, the needle cover retaining mechanism 555 extends from the arm 544 of the needle cover 506. The needle cover retaining mechanism 555 may comprise a generally radially inwardly extending projection 556. The projection 556 of the needle cover retaining mechanism 555 may be configured to abut a proximal facing surface of a structural element 585 of the housing 501 when the needle cover 506 is in the extended position to limit further extension in the distal direction of the needle cover 506 under the biasing force of the needle cover biasing member 511.

[0331] It will be appreciated that in an alternative embodiment, the needle cover retaining mechanism 555 may comprise a projection 556 extending from a component (not shown) of the housing 501 that is configured to engage within a slot in the arm 544 of the needle cover 506 with a stop (not shown) or engage with a projectionextending from the arm 544 of the needle cover 506 to limit distal travel of the needle cover 506.

[0332] Referring to Fig. 10A to 10F, in some embodiments, the needle cover 506 may comprise a plurality of arms 544. The plurality of arms 544 may be spaced circumferentially about the body portion 541 of the needle cover 506. The plurality of arms 544 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. In embodiments where two arms 544 are present, the arms 544 may be located diametrically opposite each other.

[0333] The needle cover 506 may comprise a first arm 544a and a second arm 544b. The first arm 544a may have a greater length dimension than the second arm 544b. That is, the first arm 544a may be longer than the second arm 544b. Therefore, the first arm 544a may extend further in the proximal direction than the second arm 544b.

[0334] The proximal end 547 of the first arm 544a may comprise an aperture 548. The aperture 548 may extend through the thickness of the first arm 544a of the needle cover 506. The aperture 548 may be configured to receive the collar 536 when the collar 536 is in the engaged position. That is, the collar 536 may be configured to extend through the aperture 548 when the collar 536 is in the engaged position.

[0335] The aperture 548 may comprise a first engaging surface 551. The first engaging surface 551 may be formed by a proximal end of the aperture 548. Thus, the first engaging surface 551 of the aperture 548 may be generally distally facing. In some embodiments, the first engaging surface 551 of the aperture 548 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. The inclined first engaging surface 551 may be a declined surface. That is, the inclined first engaging surface 551 may be a generally distally facing surface.The first engaging surface 551 may be configured to contact the collar 536 when needle cover 506 is in its retracted position and the collar 535 is in the engaged position, as shown in Fig. 10D.

[0336] Referring to Fig. 10A, the skin sensor 531 may comprise a body portion 561. The body portion 561 of the skin sensor 531 may be the distal most portion of the skin sensor 531. The skin sensor 531 may comprise a distal facing surface 562. The distal facing surface 562 may be configured to contact an injection site. The distal facing surface 562 of the skin sensor 531 may contact an injection site when the needle cover 506 has been moved proximally from its extended position to its initial depression position, as shown in Fig. 10B. The body portion 561 of the skin sensor 531 may extend circumferentially about the central longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500.

[0337] The body portion 561 of the skin sensor 531 may be annular. That is, the body portion 561 of the skin sensor 531 may comprise an aperture 563. The aperture 563 may be located centrally in the body portion 561 of the skin sensor 531. The aperture 563 may extend through the full thickness of the body portion 561 in a direction parallel to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500.

[0338] The skin sensor 531 may be located radially outward of the needle cover 506. Therefore, the body portion 561 of the skin sensor 531 may extend circumferentially around the needle cover 506. Thus, the aperture 563 may be configured to allow the needle cover 506 to extend therethrough when the needle cover 506 is in its extended position. The aperture 563 may also be configured to allow the needle 505 to extend therethrough when the skin sensor 531 is in the proximal position. The aperture 563 of the skin sensor 531 may be configured to receive the body portion 541 of the needle cover 506 when the needle cover 506 is in its initial depression position, as shown in Fig. 10B.

[0339] It will be appreciated that in some embodiments, the body portion 561 of the skin sensor 531 may not extend circumferentially around the whole of the needle cover 506. That is, the body portion 561 of the skin sensor 531 may extend partiallycircumferentially around the needle cover 506. In some embodiments, the body portion 561 may be formed by two or more circumferentially extending portions separated circumferentially by a gap.

[0340] The skin sensor 531 may further comprise an actuation member 564. The actuation member 564 of the skin sensor 531 may extend in the proximal direction. The actuation member 564 may extend proximally from the body portion 561 of the skin sensor 531. That is, the actuation member 564 of the skin sensor 531 may extend proximally from a proximal facing surface of the body portion 561 of the skin sensor 531.

[0341] The actuation member 564 may be elongate such that the length dimension of the actuation member 564 is greater than the width and thickness dimensions of the actuation member 564. The actuation member 564 may extend around only a section of the circumference of the body portion 561 of the skin sensor 531 , for example, but not limited to, 10% to 20% of the circumference of the skin sensor 531. Therefore, the actuation member 564 may extend arcuately around the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500.

[0342] The actuation member 564 may comprise a proximal end 567 spaced from the body portion 561 of the skin sensor 531. The proximal end 567 of the actuation member 564 may be configured to be located at a more proximal axial point within the medicament deliver device 500 than the proximal end 547 of the arm 544 of the needle cover 506 when the skin sensor 531 is in its distal position and the needle cover 506 is in its extended position, as shown in Fig. 10A, as will be described in more detail hereinafter.

[0343] In some embodiments, the length dimension of the skin sensor 531 and the length dimension of the needle cover 506 may be similar, as illustrated in Figs. 10B and 10C. The length dimension of the skin sensor 531 may be slightly larger than the length dimension of the needle cover 500. That is, the proximal most end of the actuation member 564 of the skin sensor 531 may be located proximally of the proximal most end of the arm 544 of the needle cover 506 when the needle cover506 is in its initial depression position and the skin sensor 531 is in its distal position, as shown in Fig. 10B, and when the needle cover 506 is in its retracted position and the skin sensor 531 is in its proximal position, as shown in Fig. 10C, also referred to as the latched position.

[0344] The skin sensor 531 having a slightly larger length dimension than the needle cover 506 means that the skin sensor 531 may be able to move further in the distal direction before the needle cover 506 can disengage with the collar 536 to move back towards the extended position, as will be explained in more detail hereinafter. One associated benefit is that partial accidental removal of the medicament delivery device 500 from the injection site will not cause the needle cover 506 to be released from its latched position, as will be explained in more detail hereinafter.

[0345] Referring briefly to Fig. 10F, the medicament delivery device 500 may further comprise a skin sensor retaining mechanism 569. The skin sensor retaining mechanism 569 may comprise a skin sensor projection 569a. The skin sensor projection 569a may extend generally radially outwardly from the reinforcing member 564 of the skin sensor 531. The skin sensor retaining mechanism 569 may further comprise a stop element 569b. The stop element 569b may extend from the housing 501. The stop element 569b may extend generally radially inwardly from the distal end 503 of the housing 501.

[0346] The skin sensor projection 569a of the skin sensor 531 may be configured to abut the distal facing surface of the stop element 569b of the housing 501 when the skin sensor 531 is in its distal position to limit further extension in the distal direction of the skin sensor 531 under the biasing force of the skin sensor biasing member 532.

[0347] It will be appreciated that in an alternative embodiment, the skin sensor retaining mechanism 569 may comprise a projection extending from the skin sensor 531 of the housing 501 that is configured to engage within a slot (not shown) or engage with a projection in the other of the skin sensor 531 of the housing 501 to limit distal travel of the skin sensor 531.The skin sensor 531 may comprise a plurality of actuation members 564. The plurality of actuation members 564 may be spaced circumferentially about the body portion 561 of the skin sensor 531. The plurality of actuation members 564 may be spaced equidistantly about the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. In some embodiments where two actuation members 564 are present, the actuation members 564 may be located diametrically opposite each other.

[0348] The skin sensor 531 may comprise a first actuation member 564a and a second actuation member 564b. The first actuation member 564a may have a smaller length dimension than the second actuation member 564b. That is, the first actuation member 564a may be shorter than the second actuation member 564b. Therefore, the second actuation member 564b may extend further in the proximal direction than the first actuation member 564a.

[0349] The first actuation member 564a may be located diametrically opposite to the first arm 544a of the needle cover 506. The second actuation member 564b may be located adjacent to the first arm 544a of the needle cover 506.

[0350] The proximal end 567a of the first actuation member 564a may comprise an engagement element 568. The engagement element 568 may be configured to contact the collar 536. The engagement element may comprise a first engaging surface 571. The first engaging surface 571 of the engagement element 568 may be configured to contact the collar 536 when the collar 536 is in its disengaged position and the skin sensor 531 is moved towards its proximal position.

[0351] The first engaging surface 571 may be a proximally facing surface. The first engaging surface 571 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500.

[0352] In some embodiments, the proximal end 567a of the first actuation member 564a may comprise a projection 573. The projection 573 may extend radially inwardly from the proximal end 567a of the first actuation member 564a. The projection 573may comprise a proximally facing surface that forms an extension of the first engaging surface 571 of the engagement element 568 of the first actuation member 564a.

[0353] The proximal end 567b of the second actuation member 564b may comprise an aperture 578. The aperture 578 may extend through the thickness of the second actuation member 564b of the skin sensor 531. In alternative embodiments, the aperture 578 may extend through a portion of the thickness of the second actuation member 564b to form a closed recess. The aperture 578 may be configured to receive the collar 536 when the collar 536 is in the engaged position. That is, the collar 536 may be configured to extend through or into the aperture 578 when the collar 536 is in the engaged position.

[0354] The aperture 578 in the second actuation member 564b may comprise a second engaging surface 581. The second engaging surface 581 may be formed by a proximal end of the aperture 578. Thus, the second engaging surface 581 of the aperture 578 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 535 of the medicament delivery device 500. The inclined second engaging surface 581 may be a declined surface. That is, the inclined second engaging surface 581 may be a generally distally facing surface.

[0355] The aperture 548 of the first arm 544a of the needle cover 506 and the aperture 578 of the second actuation member 564b of the skin sensor 531 may be aligned when the needle cover 506 is in its initial depression position and the skin sensor 531 is in its distal position, as shown in Fig. 10B. The apertures 548, 578 may also be aligned when the needle cover 506 is in its retracted position and the skin sensor 531 is in its proximal position, as shown in Fig. 10C.

[0356] It will be appreciated that in an alternative embodiment, the second actuation member 564b may not comprise the aperture 578 but may instead comprise a radially inwardly extending projection (not shown) comprising a second engaging surface that is configured to engage the collar 536 in the same manner as the second engaging surface 581 of the aperture 578.As shown in Figs. 10A to 10F, the retaining mechanism 535 comprises the collar 536. The collar 536 may comprise a retaining arm 537. The retaining arm 537 may be configured to contact the needle cover 506 to retain the needle cover 506 in the retracted position.

[0357] The collar 536 may comprise a first ramped surface 538. The first ramped surface 538 may be located on a side of the collar 536 proximate to the first actuation member 564a of the skin sensor 531. The first ramped surface 538 may be configured to cooperate with the first engaging surface 571 of the first actuation member 564a of the skin sensor 531 , as will be explained in more detail hereinafter. The first ramped surface 538 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 535. The inclined first ramped surface 538 of the collar 536 may be a declined surface. That is, the inclined first ramped surface 538 of the collar 536 may be a generally distally facing surface.

[0358] The collar 536 may comprise a second ramped surface 539. The second ramped surface 539 may be located on a side of the collar 536 proximate to the second actuation member 564b of the skin sensor 531. The second ramped surface 539 may be configured to cooperate with the second engaging surface 581 of the second actuation member 564b of the skin sensor 531 , as will be explained in more detail hereinafter. The second ramped surface 539 may be inclined relative to the longitudinal axis X’ of the retaining mechanism 535. The inclined second ramped surface 539 of the collar 536 may be a generally proximally facing surface.

[0359] In some embodiments, the first and second ramped surfaces 538, 539 may be located an opposite ends of the retaining arm 537 of the collar 536.

[0360] The retaining mechanism 535 comprises the collar 536. The retaining mechanism 535 may further comprise the proximally extending arm 544 of the needle cover 506, and the aperture 548 located therein. The collar 536 may be configured to extend through the aperture 548 when the collar 536 is in the engaged position, as will be explained in more detail hereinafter.The collar 536 may be configured to be moved from the disengaged position to the engaged position by movement of the skin sensor 531 from its distal position to its proximal position, see Figs. 10A and 10C.

[0361] The retaining mechanism 535 may further comprise a first proximally extending actuation member 564a of the skin sensor 531. The first actuation member 564a may be configured to contact and move the collar 536 into the engaged position when the skin sensor 531 is moved into its proximal position, as will be explained in more detail hereinafter.

[0362] The retaining mechanism 535 may further comprise a second proximally extending actuation member 564b of the skin sensor 531. The retaining mechanism 535 may comprise the second aperture 578 of the second actuation member 564b configured to receive the collar 536 when the collar is in the engaged position.

[0363] Referring to Fig. 10A, the needle cover biasing member 511 is extended such that the needle cover 506 is located in its extended position. The needle cover biasing member 511 may act on a proximally facing surface 545 of the body portion 541 of the needle cover 506 and on a structural element 585 of the housing 501. The needle cover biasing member 511 may be located radially inwardly of the arm 544 of the needle cover 506.

[0364] In Fig. 10A, the skin sensor biasing member 532 is extended such that the skin sensor 531 is in its distal position. That is, the skin sensor biasing member 532 biases the skin sensor 531 distally relative to the housing 501. The skin sensor biasing member 532 may act on a proximal end 567 of the second actuation member 564b of the skin sensor 531 and on a distal face of a component of the housing 501. The skin sensor biasing member 532 may be located proximally of the skin sensor 531 and located at the same radial distance from the longitudinal axis X’ of the retaining mechanism 535 as the second actuation member 564b of the skin sensor 531.

[0365] Referring to Fig. 10B, upon placement of the medicament delivery device 500 against an injection site, downward pressure on the medicament delivery device500 may cause the needle cover biasing member 511 to compress. Thus, the needle cover 506 may be moved from its distal position, as shown in Fig. 10A, towards its proximal position, shown in Fig. 10C, against the biasing force of the needle cover biasing member 511.

[0366] The needle cover 506 may be moved against the biasing force of the needle cover biasing member 511 until it reaches its initial compression position, as shown in Fig. 10B. In the initial compression position, the distal end of the needle cover 506 is in the same plane extending perpendicularly to the longitudinal axis X’ of the retaining mechanism 535 as the distal end of the skin sensor 531. Thus, the distal end of the needle cover 506 and the skin sensor 531 may be in contact with the injection site. The needle cover biasing member 506 may have been initially compressed. The skin sensor 531 may still be in its distal position and the skin sensor biasing member 532 may have not been compressed when compared to its pre-use position.

[0367] Therefore, the needle cover 506 may be moved into its initial depression position before the skin sensor 531 is moved from its distal position. As shown in Fig. 10B, the proximal end 567a of the first actuation member 564a of the skin sensor 531 may be located proximally of the proximal end 547 of the adjacent arm 544b of the needle cover 506.

[0368] Referring now to Fig. 10C, the needle cover 506 has been moved proximally from the initial depression position towards its retracted position against the biasing force of the needle cover biasing member 511. The skin sensor 531 has been moved proximally from its distal position to its proximal position against the biasing force of the skin sensor biasing member 532.

[0369] The skin sensor 531 may move together with the needle cover 506 such that the proximal ends 547, 567 and apertures 548, 578 of the needle cover 506 and skin sensor 531 remain in the same positioned relative to each other in the longitudinal direction X’. As shown in Fig. 10C, the retaining mechanism 535 has reached its latched position with the needle cover 506 in its retracted position, the skin sensor 531 in its proximal position, and the collar 536 in the engaged position.As the needle cover 506 and skin sensor 531 are moved proximally from the initial decompressed position shown in Fig. 10B to the latched position shown in Fig. 10C, the engagement element 568 of the first actuation member 564a of the skin sensor 531 is moved closer to the collar 536 that is located in its disengaged position.

[0370] When the needle cover 506 and the skin sensor 531 are moved far enough in the proximal direction, the first engaging surface 571 of the engagement element 568 contacts the first ramped surface 538 of the collar 536. As the skin sensor 531 moves further in the proximal direction, the incline on at least one of the first engaging surface 571 and the first ramped surface 538 cause the collar 536 to begin to move from the disengaged position towards the engaged position.

[0371] The first engaging surface 571 and the first ramped surface 538 continue to slide against each other as the skin sensor 531 moves further proximally until the skin sensor 531 reaches its proximal position. When the skin sensor 531 reaches its proximal position, the collar 536 has moved from its disengaged position to its engaged position, as shown in Fig. 10C. When the collar 536 is in the engaged position, the collar 536 extends through the aperture 548 in the needle cover 506, which is in its retracted position, and into the aperture 578 in the second actuation member 564b of the skin sensor 531.

[0372] The collar 536 may be configured to rotate from the disengaged position to the engaged position upon proximal movement of the skin sensor 531 from the distal position to the proximal position.

[0373] As a result of the engagement between the skin sensor 531 and the collar 536, the operator of the medicament delivery device 500 may feel an increase in the force required to depress the medicament delivery device 500 against an injection site. The increase in force may be as a result of overcoming friction between the two components. It will be appreciated that the incline and the length of the surfaces may be tailored to provide the desired increase in force required to depress the medicament delivery device 500 against an injection site.When the needle cover 506 is in the retracted position, the skin sensor 531 is in its proximal position, and the collar 536 is in its engaged position, the retaining mechanism 535 may be considered to be in its latched position. That is, in this position, the collar 536 may prevent distal axial movement of the needle cover 506 under the biasing force of the needle cover biasing member 511. The collar 536 may be prevented from being rotated from the engaged position to the disengaged position by the first engaging surface 571 of the first actuating member 564a of the skin sensor 531 , which is prevented from moving distally by an operator holding the device 500 against an injection site.

[0374] By placing the collar 536 in the aperture 548 of the arm 544 of the needle cover 506, the biasing force of the needle cover biasing member 511 is transferred from the needle cover 506 to the collar 536, which is mounted to the housing 501 such that the collar 536 cannot move axially. Therefore, the operator of the device 500 may hold the device 500 against a reduced hold force that includes the biasing force of the skin sensor biasing member 532 but does not include the biasing force of the needle cover biasing member 511.

[0375] Referring briefly to Fig. 10D, the retaining mechanism 535 is shown in its latched hold position. The collar 536 is in its engaged position. In the engaged position, the collar 536 has been rotated by such a distance that the second ramped surface 539 of the collar 536 is radially outward of the arm 544 of the needle cover 506. Therefore, a flat proximally facing surface of the collar 536 is in contact with the first engaging surface 551 of the arm 544 of the needle cover 506. Thus, downward pressure of the needle cover 506 on the collar 536 when the collar 536 is in the engaged position cannot move the collar 536 out of the engaged position.

[0376] The distal ends of the apertures 548, 578 in the needle cover 506 and the skin sensor 531 are located at the same longitudinal position. The proximal end of the aperture 578 of the skin sensor 531 is located proximally of the proximal end of the aperture 548 of the needle cover 506. Thus, the second engaging surface 581 of the second actuation member 564b of the skin sensor 531 is spaced further from the collar 536 than the proximal end of the aperture 548 of the needle cover 506.Referring now to Fig. 10E, once the medicament delivery device 500 is removed from the injection site, the compressive forces on the skin sensor biasing member 532 may be removed.

[0377] In the case of accidental partial removal of the medicament delivery device 500 from the injection site, the skin sensor 531 may be urged distally from its proximal position towards its distal position by the skin sensor biasing member 532.

[0378] However, due to the proximal end of the aperture 578 of the second actuation member 564b of the skin sensor 531 being located further in a more proximal location than the collar 536, the skin sensor 531 may move distally relative to the needle cover 506 by a predetermined distance before the second engaging surface 581 of the second actuation member 564b can contact the collar 536 to move the collar out of the engaged position.

[0379] Thus, if the medicament delivery device 500 is accidentally partially lifted from the injection site, the retaining mechanism 535 does not release immediately. This means that an operator can reapply the pressure to the medicament delivery device 500 and the injection sire without having to overcome the additional force of the needle cover biasing member 511 as the force of the needle cover biasing member 511 is still being transferred to the housing 501 by the contact between the collar 536 and the needle cover 506.

[0380] Once the medicament delivery device 500 is removed from the injection site, the compressive forces on the skin sensor biasing member 532 are removed. In the case shown in Fig. 10E, the medicament delivery device 500 may have been deliberately removed or accidentally removed by more than the predetermined distance.

[0381] Since there is no longer a compressive force acting on the skin sensor 531 , the skin sensor biasing member 532 is able to extend. Thus, the skin sensor 531 is moved towards its distal position under the force of the skin sensor biasing member 532.When the skin sensor 531 is moved distally from its proximal position by a distance greater than the predetermined distance, the second engaging surface 581 of the second actuation member 564b of the skin sensor 531 is pushed into contact with the second ramped surface 539 of the collar 536. Under the biasing force of the skin sensor biasing member 532, the skin sensor 531 is pushed further distally. The second engaging surface 581 of the second actuation member 564b and the second ramped surface 539 of the collar 536 continue to slide against each other causing the collar 536 to rotate from the engaged position towards the disengaged position.

[0382] Once the skin sensor 531 has returned to its distal position, the proximal end of the aperture 548 in the arm 544 of the needle cover 506 is in contact with the second ramped surface 539 of the collar 536. At this stage, the first engaging surface 551 of the arm 544 of the needle cover 506 is able to move distally under the force of the needle cover biasing member 511 and slide against the second ramped surface 539 of the collar 536 to move the collar 536 into its disengaged position. Once the collar 536 is rotated out of contact with the first engaging surface 551 of the arm 544 of the needle cover 506, the needle cover biasing member 511 is free to extend and move the needle cover 506 back to the extended position, as shown in Fig. 10F.

[0383] The medicament delivery device 500 may further comprise a needle cover lock. The needle cover lock may be configured to prevent proximal movement of the needle cover 506 once the needle cover 506 is in the extended position post-use.

[0384] Although described previously in detail, a brief description of the method of preparing a medicament delivery device 500 for use will be described hereinafter. The method comprises moving a needle cover 506 from its extended position to a decompression position against the force of a needle cover biasing member 511. The method further comprises moving the needle cover 506 from the decompression position to a retracted position and a skin sensor 531 from a distal position to a retracted position simultaneously. The method further comprises moving the skin sensor 531 from the distal position to the proximal position moves a collar 536 from a disengaged position to an engaged position, in which the collar536 is configured to temporarily retain the needle cover 506 in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member 511 to the housing 501 such that the needle cover biasing member 511 is prevented from moving the needle cover 506 distally.

[0385] In addition, although described previously in detail, a brief description of the method of extending a needle cover 506 of a medicament delivery device 500 after use will be described hereinafter. The method comprises removing the medicament delivery device 500 from an injection site and moving the skin sensor 531 distally from a proximal position to a distal position under the force of a skin sensor biasing member 532. The method further comprises moving the collar 536 from the engaged position to the disengaged position, and moving the needle cover 506 in the distal direction from a retracted position to an extended position, under the biasing force of a needle cover biasing member 511. The method may further comprising engaging a locking mechanism to prevent proximal movement of the needle cover 506.

[0386] The features described and / or contemplated in relation to the medicament delivery device 500 may be incorporated in another medicament delivery device., for example, a medicament delivery device having a different mechanism for dispensing medicament to that described in relation to the medicament delivery device 100, and / or a medicament delivery device which is configured to inject 2ml or less of medicament and / or a medicament delivery device which is configured to inject a medicament having a viscosity of 25cP or less, and / or a medicament delivery device in which the medicament is contained in a cartridge which is initially separated from the needle when the needle cover is in the initial position.

[0387] The terms “drug” or “medicament” are used synonymously herein and describe a pharmaceutical formulation containing one or more active pharmaceutical ingredients or pharmaceutically acceptable salts or solvates thereof, and optionally a pharmaceutically acceptable carrier. An active pharmaceutical ingredient (“API”), in the broadest terms, is a chemical structure that has a biological effect onhumans or animals. In pharmacology, a drug or medicament is used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. A drug or medicament may be used for a limited duration, or on a regular basis for chronic disorders.

[0388] As described below, a drug or medicament can include at least one API, or combinations thereof, in various types of formulations, for the treatment of one or more diseases. Examples of API may include small molecules having a molecular weight of 500 Da or less; polypeptides, peptides and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes); carbohydrates and polysaccharides; and nucleic acids, double or single stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids may be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more drugs are also contemplated.

[0389] The drug or medicament may be contained in a primary package or “drug container” adapted for use with a drug delivery device. The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., short- or long-term storage) of one or more drugs. For example, in some instances, the chamber may be designed to store a drug for at least one day (e.g., 1 to at least 30 days). In some instances, the chamber may be designed to store a drug for about 1 month to about 2 years. Storage may occur at room temperature (e.g., about 20°C), or refrigerated temperatures (e.g., from about - 4°C to about 4°C). In some instances, the drug container may be or may include a dual-chamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and / or during dispensing into the human or animal body. For example, the two chambers may be configured such that they are in fluid communication with each other (e.g., by way of a conduit between the two chambers) and allow mixing of the twocomponents when desired by a user prior to dispensing. Alternatively or in addition, the two chambers may be configured to allow mixing as the components are being dispensed into the human or animal body.

[0390] The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and / or prophylaxis of many different types of medical disorders. Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and / or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as Rote Liste 2014, for example, without limitation, main groups 12 (anti-diabetic drugs) or 86 (oncology drugs), and Merck Index, 15th edition.

[0391] Examples of APIs for the treatment and / or prophylaxis of type 1 or type 2 diabetes mellitus or complications associated with type 1 or type 2 diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-1), GLP-1 analogues orGLP-1 receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-4 (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms “analogue” and “derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and / or exchanging at least one amino acid residue occurring in the naturally occurring peptide and / or by adding at least one amino acid residue. The added and / or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as "insulin receptor ligands". In particular, the term ..derivative” refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g.., a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acidsoccurring in the naturally occurring peptide may have been deleted and / or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide.

[0392] Examples of insulin analogues are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin (insulin glulisine); Lys(B28), Pro(B29) human insulin (insulin lispro); Asp(B28) human insulin (insulin aspart); human insulin, wherein proline in position B28 is replaced by Asp, Lys, Leu, Vai or Ala and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin.

[0393] Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); 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-omega-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(w-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(w-carboxyheptadecanoyl) human insulin.

[0394] Examples of GLP-1 , GLP-1 analogues and GLP-1 receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-4, Byetta®, Bydureon®, a 39 amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), rExendin-4, CJC-1134-PC, PB-1023, TTP-054, Langlenatide / HM-11260C (Efpeglenatide), HM-15211, CM-3, GLP-1 Eligen, ORMD-0901, NN-9423, NN-9709, NN-9924, NN-9926, NN-9927, Nodexen, Viador-GLP-1 , CVX-096, ZYOG-1, ZYD-1 , GSK-2374697, DA-3091, MAR-701, MAR709, ZP-2929, ZP-3022, ZP-DI-70, TT-401 (Pegapamodtide), BHM-034.MOD-6030, CAM-2036, DA-15864, ARI-2651 , ARI-2255, Tirzepatide (LY3298176), Bamadutide (SAR425899), Exenatide-XTEN and Glucagon-Xten.

[0395] An example of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a caperturesterol-reducing antisense therapeutic for the treatment of familial hypercaperturesterolemia or RG012 for the treatment of Alport syndrom.

[0396] Examples of DPP4 inhibitors are Linagliptin, Vildagliptin, Sitagliptin, Denagliptin, Saxagliptin, Berberine.

[0397] Examples of hormones include hypophysis hormones or hypothalamus hormones or regulatory active peptides and their antagonists, such as Gonadotropine (Follitropin, Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin), Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin, Buserelin, Nafarelin, and Goserelin.

[0398] Examples of polysaccharides include a glucosaminoglycane, a hyaluronic acid, a heparin, a low molecular weight heparin or an ultra-low molecular weight heparin ora derivative thereof, ora sulphated polysaccharide, e.g. a poly-sulphated form of the above-mentioned polysaccharides, and / or a pharmaceutically acceptable salt thereof. An example of a pharmaceutically acceptable salt of a poly-sulphated low molecular weight heparin is enoxaparin sodium. An example of a hyaluronic acid derivative is Hylan G-F 20 (Synvisc®), a sodium hyaluronate.

[0399] The term “antibody”, as used herein, refers to an immunoglobulin molecule or an antigen-binding portion thereof. Examples of antigen-binding portions of immunoglobulin molecules include F(ab) and F(ab')2 fragments, which retain the ability to bind antigen. The antibody can be polyclonal, monoclonal, recombinant, chimeric, de-immunized or humanized, fully human, non-human, (e.g., murine), or single chain antibody. In some embodiments, the antibody has effector function and can fix complement. In some embodiments, the antibody has reduced or no ability to bind an Fc receptor. For example, the antibody can be an isotype or subtype, an antibody fragment or mutant, which does not support binding to an Fc receptor, e.g., it has a mutagenized or deleted Fc receptor binding region. Theterm antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and / or a dual variable region antibodylike binding protein having cross-over binding region orientation (CODV).

[0400] The terms “fragment” or “antibody fragment” refer to a polypeptide derived from an antibody polypeptide molecule (e.g., an antibody heavy and / or light chain polypeptide) that does not comprise a full-length antibody polypeptide, but that still comprises at least a portion of a full-length antibody polypeptide that is capable of binding to an antigen. Antibody fragments can comprise a cleaved portion of a full length antibody polypeptide, although the term is not limited to such cleaved fragments. Antibody fragments that are useful in the present invention include, for example, Fab fragments, F(ab')2 fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, tetraspecific and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), monovalent or multivalent antibody fragments such as bivalent, trivalent, tetravalent and multivalent antibodies, minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art.

[0401] The terms “Complementarity-determining region” or “CDR” refer to short polypeptide sequences within the variable region of both heavy and light chain polypeptides that are primarily responsible for mediating specific antigen recognition. The term “framework region” refers to amino acid sequences within the variable region of both heavy and light chain polypeptides that are not CDR sequences, and are primarily responsible for maintaining correct positioning of the CDR sequences to permit antigen binding. Although the framework regions themselves typically do not directly participate in antigen binding, as is known in the art, certain residues within the framework regions of certain antibodies can directly participate in antigen binding or can affect the ability of one or more amino acids in CDRs to interact with antigen.Examples of antibodies are anti PCSK-9 mAb (e.g., Alirocumab), anti IL-6 mAb (e.g., Sarilumab), and anti IL-4 mAb (e.g., Dupilumab).

[0402] Pharmaceutically acceptable salts of any API described herein are also contemplated for use in a drug or medicament in a drug delivery device.

[0403] Pharmaceutically acceptable salts are for example acid addition salts and basic salts.

[0404] Those of skill in the art will understand that modifications (additions and / or removals) of various components of the APIs, formulations, apparatuses, methods, systems and embodiments described herein may be made without departing from the full scope and spirit of the present invention, which encompass such modifications and any and all equivalents thereof.

[0405] An example drug delivery device may involve a needle-based injection system as described in Table 1 of section 5.2 of ISO 11608-1 :2014(E). As described in ISO 11608-1 :2014(E), needle-based injection systems may be broadly distinguished into multi-dose container systems and single-dose (with partial or full evacuation) container systems. The container may be a replaceable container or an integrated non-replaceable container.

[0406] As further described in ISO 11608-1 :2014(E), a multi-dose container system may involve a needle-based injection device with a replaceable container. In such a system, each container holds multiple doses, the size of which may be fixed or variable (pre-set by the user). Another multi-dose container system may involve a needle-based injection device with an integrated non-replaceable container. In such a system, each container holds multiple doses, the size of which may be fixed or variable (pre-set by the user).

[0407] As further described in ISO 11608-1:2014(E), a single-dose container system may involve a needle-based injection device with a replaceable container. In one example for such a system, each container holds a single dose, whereby the entire deliverable volume is expelled (full evacuation). In a further example, each container holds a single dose, whereby a portion of the deliverable volume isexpelled (partial evacuation). As also described in ISO 11608-1:2014(E), a singledose container system may involve a needle-based injection device with an integrated non-replaceable container. In one example for such a system, each container holds a single dose, whereby the entire deliverable volume is expelled (full evacuation). In a further example, each container holds a single dose, whereby a portion of the deliverable volume is expelled (partial evacuation).

[0408] An example of a compound to be administered with the drug delivery device disclosed herein is a compound with the INN tirzepatide, as referenced in claim 1 of US patent no. 9,474,780.

[0409] An example of a pharmaceutical composition to be administered with the drug delivery device disclosed herein is a pharmaceutical composition as referenced in US patent no. 11 ,357,820.

[0410] An example of a pharmaceutical composition to be administered with the drug delivery device disclosed herein includes a 0.5 mL solution of 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, or 15 mg of tirzepatide and the following excipients sodium chloride (4.1 mg), sodium phosphate dibasic heptahydrate (0.7 mg), and water for injection. Hydrochloric acid solution and / or sodium hydroxide solution may be added to adjust the pH.

[0411] An example starting dosage tirzepatide may be 2.5 mg injected subcutaneously once weekly. After four weeks, the tirzepatide dosage may be increased to 5 mg injected subcutaneously once weekly. The dosage may be further increased in 2.5 mg increments after at least four weeks on the current dose. In an example, the maximum dosage of tirzepatide may be 15 mg injected subcutaneously once weekly. If a dose is missed, patients may be instructed to administer tirzepatide as soon as possible within four days (96 hours) after the missed dose. If more than four days have passed, patients may skip the missed dose and administer the next dose on the regularly scheduled day. In each case, patients may then resume their regular once weekly dosing schedule. The day of weekly administration may be changed, if necessary. The time between two doses may be at least three days (72 hours).Tirzepatide dosages may include 2.5 mg / 0.5 mL, 5 mg / 0.5 mL, 7.5 mg / 0.5 mL, 10 mg / 0.5 mL, 12.5 mg / 0.5 mL, and 15 mg / 0.5 mL. Tirzepatide may be stored in a refrigerator at 2°C to 8°C (36°F to 46°F). A single-dose pen or single-dose vial may be stored unrefrigerated at temperatures not to exceed 30°C (86°F) for up to 21 days. Tirzepatide may be stored in a carton.

[0412] CLAUSES

[0413] The following clauses form a part of the disclosure:

[0414] 1. A medicament delivery device (400) comprising:

[0415] a housing (401) comprising a proximal end and a distal end (403);

[0416] a needle (405) and a needle cover (406);

[0417] wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end (407) of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end (408) of the needle cover;

[0418] a needle cover biasing member (411) configured to bias the needle cover axially in the distal direction towards the extended position;

[0419] a skin sensor (431) extending from the distal end of the housing, the skin sensor being axially moveable between a distal position, in which the needle cover is free to move axially, and a proximal position, in which the skin sensor limits axial movement of the needle cover;

[0420] a skin sensor biasing member (432) configured to bias the skin sensor axially in the distal direction towards its distal position, wherein the skin sensor biasing member acts on the housing at its proximal end and the skin sensor at its distal end;

[0421] wherein the distal end of the skin sensor is located proximally of the distal end of the needle cover when the needle cover is in its extended position; and a retaining mechanism (435) configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the forceof the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0422] 2. The medicament delivery device (400) according to clause 1 , wherein the retaining mechanism (435) is configured to transfer substantially the full force of the needle cover biasing member (411 ) to the housing (401 ) when the needle cover (406) in in the retracted position and the skin sensor (431) is in the proximal position.

[0423] 3. The medicament delivery device (400) according to clause 1 or clause 2, wherein the retaining mechanism (435) comprises a proximally extending arm (444) of the needle cover (406), the arm comprising a projection (448) on its proximal end (447), and a catch located on a structural element of the housing (401), wherein the projection is configured to engage the catch when the needle cover is in its retracted position.

[0424] 4. The medicament delivery device (400) according to clause 3, wherein the structural element of the housing (401) is located radially inwardly of the arm (444) of the needle cover (406).

[0425] 5. The medicament delivery device (400) according to clause 3 or clause 4, wherein the proximal end (447) of the arm (444) of the needle cover (406) is deflectable in a radially outward direction.

[0426] 6. The medicament delivery device (400) according to clause 5, wherein the projection (448) extends radially inwards and comprises an inclined engaging surface (451).

[0427] 7. The medicament delivery device (400) according to any one of clause 3 to clause 6, wherein the retaining mechanism (435) further comprises a proximally extending reinforcing member (464) of the skin sensor (431) configured to prevent the projection (448) disengaging from the catch (471) when the needle cover (406) is held in the retracted position and the skin sensor is held in the proximal position.8. The medicament delivery device (400) according to clause 7, wherein the reinforcing member (464) of the skin sensor (431) is located radially outwards of the arm (444) of the needle cover (406).

[0428] 9. The medicament delivery device (400) according to clause 7 or clause 8, wherein upon depression of the device against an injection site, the needle cover (406) is configured to be moved proximally from its extended position towards its retracted position before the skin sensor (431) is moved from its distal position.

[0429] 10. The medicament delivery device (400) according to any one of clause 7 to clause 9, wherein the needle cover (406) is movable into an initial depression position in which the distal end of the needle cover extends in the same plane as the distal end of the skin sensor (431 ).

[0430] 11. The medicament delivery device (400) according to clause 10, wherein the needle cover (406) and skin sensor (431) are moveable together from the initial depression position into their respective retracted and proximal positions.

[0431] 12. The medicament delivery device (400) according to any one of clause 7 to clause 11 , wherein upon removal of the device from an injection site, the skin sensor (431 ) is moveable from its proximal position to its distal position under the force of the skin sensor biasing member (432) before the needle cover (406) is moveable from its retracted position under the force of the needle cover biasing member (411).

[0432] 13. The medicament delivery device (400) according to any one of the preceding clauses, wherein the medicament delivery device comprises medicament.

[0433] 14. A method of preparing a medicament delivery device (400) for use, the method comprising:

[0434] moving a needle cover (406) from its extended position to an initial compression position against the force of a needle cover biasing member (411);moving the needle cover and a skin sensor (431) from the initial compression position to their respective retracted and proximal positions against the force of the needle cover biasing member and the skin sensor biasing member (432);

[0435] engaging a projection (448) on an arm (444) of the needle cover with a catch (471) located on structural element of the housing (401) located radially inwardly of the needle cover, and maintaining the projection in engagement with the catch with a reinforcing member (464) of the skin sensor in a latched position, wherein in the latched position the force of the needle cover biasing member is transferred to the housing.

[0436] 15. A method of extending a needle cover (406) of a medicament delivery device (400) after medicament has been dispensed from the medicament deliver device, the method comprising:

[0437] removing the medicament delivery device from an injection site; moving the skin sensor (431) distally from a proximal position to a distal position under the force of a skin sensor biasing member (432);

[0438] disengaging a projection (448) of an arm (444) of a needle cover from a catch (471) located on a housing (401) under the force of the needle cover biasing member (411) when the skin sensor has reached the distal position; and moving the needle cover in the distal direction from its retracted position to its extended position.

[0439] 16. A medicament delivery device (500) comprising:

[0440] a housing (501) comprising a proximal end and a distal end (503);

[0441] a needle (505) and a needle cover (506);

[0442] wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end (507) of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end (508) of the needle cover;

[0443] a needle cover biasing member (511) configured to bias the needle cover axially in the distal direction towards the extended position;a skin sensor (531) extending from the distal end of the housing, the skin sensor being axially moveable between a distal position, in which the needle cover is free to move axially, and a proximal position;

[0444] a skin sensor biasing member (532) configured to bias the skin sensor axially in the distal direction towards its distal position;

[0445] a retaining mechanism (535) comprising a collar (536) axially fixed within the housing, the collar configured to be moveable between a disengaged position when the skin sensor is in its distal position, and an engaged position when the skin sensor is in its proximal position and the needle cover is in its retracted position, in which the collar is configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

[0446] 17. The medicament delivery device (500) according to clause 16, wherein the retaining mechanism (535) is configured to transfer substantially the full force of the needle cover biasing member (511 ) to the housing (501 ) when the collar (536) is in the engaged position.

[0447] 18. The medicament delivery device according to clause 16 or clause 17, wherein the retaining mechanism (535) further comprises a proximally extending arm (544) of the needle cover (506), wherein a proximal end (547) of the arm of the needle cover comprises an aperture (548), wherein the collar is configured to extend through the aperture when the collar is in the engaged position.

[0448] 19. The medicament delivery device (500) according to clause 18, wherein the collar (536) is configured to be moved from the disengaged position to the engaged position by movement of the skin sensor (331) from its distal position to its proximal position.

[0449] 20. The medicament delivery device (500) according to clause 19, wherein the retaining mechanism further comprises a first proximally extending actuation member (564a) of the skin sensor (531 ), the first actuation member beingconfigured to contact and move the collar into the engaged position when the skin sensor is moved into its proximal position.

[0450] 21. The medicament delivery device (500) according to clause 20, wherein the proximal end of the first actuation member (564a) of the skin sensor (531) comprises an inclined first engaging surface (571) configured to cooperate with a declined first ramped surface (538) of the collar (536).

[0451] 22. The medicament delivery device (500) according to clause 21 , wherein the proximal end of the first actuation member (564a) comprises an inwardly extending projection (573) forming at least a part of the inclined first engaging surface (571).

[0452] 23. The medicament delivery device (500) according any one of clause 19 to clause 22, wherein the collar (536) is configured to be moved from the engaged position to the disengaged position by movement of the skin sensor (531) from its proximal position to its distal position.

[0453] 24. The medicament delivery device (500) according to clause 23, wherein the retaining mechanism (535) further comprises a second proximally extending actuation member (564b) of the skin sensor (531), the second actuation member comprising a second aperture (578) configured to receive the collar (536) when the collar is in the engaged position.

[0454] 25. The medicament delivery device (500) according to clause 24, wherein the proximal end of the aperture (578) of the second actuation member (564b) of the skin sensor (531) comprises a declined second engaging surface (581) configured to cooperate with an inclined first ramped surface (539) of the collar (536).

[0455] 26. The medicament delivery device (500) according to clause 18 and clause 24, wherein the needle cover (506) is movable into an initial depression position in which the distal end of the needle cover extends in the same plane as the distal end of the skin sensor (531) and the first and second apertures (548, 578) arealigned, and the needle cover and skin sensor are moveable together from the initial depression position into their respective retracted and proximal positions.

[0456] 27. The medicament delivery device (500) according to any one of clause 16 to clause 26, wherein upon removal of the device from an injection site, the skin sensor (531) is moveable from its proximal position towards its distal position under the force of the skin sensor biasing member (532) and the collar (536) is moved from its engaged position to its disengaged position before the needle cover (506) is moveable from its retracted position under the force of the needle cover biasing member (511 ).

[0457] 28. The medicament delivery device (500) according to any one of clause 16 to clause 27, wherein the collar (536) is rotatable between the disengaged position and the engaged position.

[0458] 29. The medicament delivery device (500) according to any one of clause 16 to clause 28, wherein the medicament delivery device comprises medicament.

[0459] 30. A method of preparing a medicament delivery device (500) for use, the method comprising:

[0460] moving a needle cover (506) from an extended position to a decompression position,

[0461] moving the needle cover from the decompression position to a retracted position and a skin sensor (531) from a distal position to a retracted position simultaneously,

[0462] wherein moving the skin sensor from the distal position to the proximal position moves a collar (536) from a disengaged position to an engaged position in which the collar is configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of the force of the needle cover biasing member to the housing (501 ) such that the needle cover biasing member (511) is prevented from moving the needle cover distally.REFERENCE NUMERALS

[0463] 10 Medicament Delivery Device 35 217 Needle Cover Side Walls 11 Housing 218 Needle Cover

[0464] 12 Cap Assembly 219 Contact Face

[0465] 13 Needle Sleeve 227 Skin Sensor

[0466] 17 Needle 300 Medicament Delivery Device 20 Distal Region 40 301 Housing

[0467] 21 Proximal Region 303 Distal End

[0468] 22 Button 305 Needle

[0469] 23 Piston 306 Needle Cover

[0470] 100 Medicament Delivery Device 307 Distal End

[0471] 101 Housing 45 308 Distal End

[0472] 102 Proximal End 311 Needle Cover Biasing Member 103 Distal End 331 Skin Sensor

[0473] 105 Needle 332 Skin Sensor Biasing Member 106 Needle Cover 335 Retaining Mechanism

[0474] 107 Distal End 50 341 Body Portion

[0475] 108 Distal End 342 Aperture

[0476] 111 Needle Cover Biasing Member 343 Distal Facing Surface

[0477] 115 Plunger 344 Arm

[0478] 116 Syringe 345 Proximally Facing Surface 117 Piston 55 347 Proximal End

[0479] 119 Collar 348 Projection

[0480] 122 Screw Thread 349 Protrusion

[0481] 124 Drive Member 351 First Engaging Surface 125 Injection Site 352 Second Engaging Surface 200 Medicament Delivery Device 60 353 Skin Sensor Engaging Surface 201 Housing 355 Slot

[0482] 203 Distal End 356 Skin Sensor Retaining 205 Needle Element

[0483] 206 Plunger 357 Projection

[0484] 215 Needle Carrier 65 358 Retaining Member

[0485] 216 Needle 358a Slot359 Retaining Member 444 Arm

[0486] 361 Body Portion 35 445 Proximal Facing Surface 362 Distal Facing Surface 447 Proximal End

[0487] 363 Aperture 448 Projection

[0488] 364 Reinforcing Member 451 First Engaging Surface 364a Distal Portion 452 Second Engaging Surface 364b Proximal Portion 40 455 Needle Cover Retaining 367 Proximal End Mechanism

[0489] 368 Slot 456 Projection

[0490] 368a Stop 461 Body Portion

[0491] 369 Flange 462 Distal Facing Surface 371 Catch 45 463 Aperture

[0492] 372 Recess 464 Reinforcing Member 373 Inner Surface 464a Distal Portion

[0493] 373a Ramped Portion 464b Proximal Portion

[0494] 374 Proximally Facing Surface 467 Proximal End

[0495] 381 Structural Element 50 468 Projection

[0496] 391 Needle Cover Lock 469 Skin Sensor Retaining 395 Structural Element Mechanism

[0497] 400 Medicament Delivery Device 469a Skin Sensor Projection 401 Housing 469b Stop Element

[0498] 403 Distal End 55 471 Catch

[0499] 405 Needle 472 Structural Element

[0500] 406 Needle Cover 472a First Part

[0501] 407 Distal End 472b Second Part

[0502] 408 Distal End 473 Inner Surface

[0503] 411 Needle Cover Biasing Member 60 474 Protrusion

[0504] 431 Skin Sensor 475 Proximally Facing Surface 432 Skin Sensor Biasing Member 476 Ramped Portion / Distally 435 Retaining Mechanism Facing Surface

[0505] 441 Body Portion 477 Structural Element 442 Aperture 65 481 Structural Element 443 Distal Facing Surface 500 Medicament Delivery Device501 Housing 25 555 Needle Cover Retaining 503 Distal End Element

[0506] 505 Needle 556 Radially Inwardly Extending 506 Needle Cover Projection

[0507] 507 Distal End 561 Body Portion

[0508] 508 Distal End 30 562 Distal Facing Surface 511 Needle Cover Biasing Member 563 Aperture

[0509] 531 Skin Sensor 564 Actuation Member 532 Skin Sensor Biasing Member 564a First Actuation Member 535 Retaining Mechanism 564b Second Actuation Member 536 Collar 35 567 Proximal End

[0510] 537 Retaining Arm 567a Proximal End

[0511] 538 First Ramped Surface 567b Proximal End

[0512] 539 Second Ramped Surface 568 Engagement Element 541 Body Portion 569 Skin Sensor Retaining 542 Aperture 40 Mechanism

[0513] 543 Distal Facing Surface 569a Skin Sensor Projection 544 Arm 569b Stop Element

[0514] 544a First Arm 571 First Engaging Surface 544b Second Arm 573 Projection

[0515] 545 Proximally Facing Surface 45 578 Aperture

[0516] 547 Proximal End 581 Second Engaging Surface 548 Aperture 585 Structural Element 551 First Engaging Surface

Claims

PAT24299-EP-EPAClaims1. A medicament delivery device (300) comprising:a housing (301) comprising a proximal end and a distal end (303);a needle (305) and a needle cover (306);wherein the needle cover is axially moveable between an extended position, in which the needle cover extends from the distal end of the housing and covers a distal end (307) of the needle, and a retracted position, in which the needle cover is located in a proximal position relative to the extended position such that the needle protrudes from a distal end (308) of the needle cover;a needle cover biasing member (311) configured to bias the needle cover axially in a distal direction towards the extended position;a skin sensor (331) extending distally from the distal end of the needle cover and configured to contact an injection site;a skin sensor biasing member (332) acting between the needle cover and the skin sensor, the skin sensor biasing member being configured to bias the skin sensor axially in the distal direction from a proximal position to a distal position away from the needle cover;a retaining mechanism (335) comprising:a proximally extending arm (344) of the needle cover (306), the arm comprising a projection (348) on its proximal end (347),a catch (371) located on an inner surface of the housing (301), wherein the projection is configured to engage the catch when the needle cover is in its retracted positiona proximally extending reinforcing member (364) of the skin sensor (331) configured to prevent the projection (348) disengaging from the catch (371) when the needle cover (306) is held in the retracted position and the skin sensor is held in the proximal positionthe retaining mechanism being configured to temporarily retain the needle cover in the retracted position and temporarily transfer at least a part of a force ofthe needle cover biasing member to the housing such that the needle cover biasing member is prevented from moving the needle cover distally.

2. The medicament delivery device (300) according to claim 1 , wherein the retaining mechanism (335) is configured to transfer substantially the full force of the needle cover biasing member (311) to the housing (301) when the needle cover (306) is in the retracted position and the skin sensor (331) is in the proximal position.

3. The medicament delivery device (300) according to claim 1 or claim 2, wherein the proximal end (347) of the arm (344) of the needle cover (306) is deflectable in a radial direction.

4. The medicament delivery device (300) according to claim 3, wherein the projection (348) comprises an inclined engaging surface (351).

5. The medicament delivery device (300) according to any one of the preceding claims, wherein the reinforcing member (364) of the skin sensor (331) is located radially inwards of the arm (344) of the needle cover (306).

6. The medicament delivery device (300) according to claim 5, wherein the needle cover (306) comprises an annular member (341) having a slot (355) adjacent to the arm (344), wherein the reinforcing member (364) of the skin sensor (331) extends and is moveable axially through the slot.

7. The medicament delivery device (300) according to any one of the preceding claims, wherein the reinforcing member (364) of the skin sensor (331) is stiffer than the arm (344) of the needle cover (306).

8. The medicament delivery device (300) according to any one of the preceding claims, wherein upon depression of the device against an injection site, the skin sensor (331) is configured to be moved from the distal position to the- 106 -proximal position before the needle cover (306) is moved from the extended position to the retracted position.

9. The medicament delivery device (300) according to claim 8, wherein when the needle cover (306) is in its retracted position and the skin sensor (331) is in its proximal position relative to the needle cover, the proximal end (367) of the reinforcing member (364) is located proximally of the proximal end (347) of the arm (344), and optionally,wherein the proximal end (367) of the reinforcing member (364) is located proximally of the proximal end (347) of the arm (344) by a predetermined distance and is configured to prevent unlatching of the retaining mechanism when the medicament delivery device is initially moved away from the injection site.

10. The medicament delivery device (300) according to any one of the preceding claims, wherein the needle cover (306) comprises a skin sensor retaining element (356) extending radially inwardly, and the skin sensor (331) comprises a longitudinally extending slot (368) in the reinforcing member (364), the skin sensor retaining element (356) and slot (368) being configured to limit the longitudinal movement of the skin sensor (331 ) relative to the needle cover (306).

11. The medicament delivery device (300) according to any one of the preceding claims, wherein the housing (301) comprises an inner surface (373) with a ramped portion (373a), the ramped portion being configured to bias an arm (344) of the needle cover (306) radially inwards, and wherein the catch (371) is located at the proximal end of the ramped portion of the inner surface.

12. The medicament delivery device according to any one of the preceding claims, wherein the medicament delivery device comprises medicament.

13. A method of preparing a medicament delivery device for use, the method comprising:moving a skin sensor from a distal position to a proximal position against the force of a skin sensor biasing member;- 107 - moving the skin sensor and a needle cover proximally from an extended position to a retracted position within a housing;engaging a projection on an arm of the needle cover with a catch located in the housing and maintaining the projection in engagement with the catch located in the housing and maintaining the projection in engagement with the catch with a reinforcing member of the skin sensor, wherein engaging the needle cover with the housing transfers the force of the needle cover biasing member to the housing.

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