CN118201658A - Drug delivery device - Google Patents

Abstract

A drug delivery device is disclosed wherein an activation element is arranged to prevent lateral movement of a syringe plunger until the drug delivery device is activated. When the drug delivery device is activated, the activation element is displaced, allowing the plunger to move laterally under the influence of the drive element.

Description

Drug delivery device

Background

Drug delivery devices, such as auto-injectors, injection pens and patch pumps, may be used to automatically deliver injected drugs.

Drug delivery devices may be of a variety of sizes and designs, and at least a portion of each device is typically discarded once one or more doses of drug have been delivered. This "disposable" nature of the drug delivery device results in the production of large amounts of waste, which is typically treated as biomedical sharps waste and thus incinerated.

Furthermore, existing drug delivery devices often have complex activation mechanisms that are expensive to manufacture and complex to assemble. For example, US2016/0199588 A1 discloses an automatic injector having a plunger activation mechanism in which the plunger is released by rotating a plunger boss out of a bayonet slot. During assembly, the plunger is inserted into the housing and rotated such that the boss on the plunger engages the bayonet slot.

Drug delivery devices having fewer components and/or components made of more environmentally friendly materials are needed to reduce the environmental burden of these devices. However, some environmentally friendly materials (such as biopolymers) are not as strong as traditional materials (such as ordinary polymers) and lack the long term strength necessary to withstand the relatively strong forces exerted by components such as drive springs used in certain drug delivery devices.

The object of the present invention is to provide a drug delivery device that is reliable, simple to assemble and can be made of environmentally friendly materials.

Disclosure of Invention

According to a first aspect of the present invention there is provided a drug delivery device comprising: a housing; a syringe received within the housing and including a plunger, wherein the plunger includes a first guide surface arranged to abut a second guide surface within the housing at a non-perpendicular angle relative to a longitudinal axis of the plunger; a drive element arranged to apply a depressing force to the plunger; and an activation element movable between a first (or initial) position in which the activation element is arranged to inhibit lateral movement of the plunger within the housing and a second (or activated) position in which the activation element is arranged to allow lateral movement of at least a portion of the plunger within the housing, wherein when the activation element is displaced from the first position to the second position, abutment between the first and second guide surfaces causes lateral displacement of at least a portion of the plunger due to a depressing force of the drive element, thereby releasing the plunger to move from the undepressed position to the depressed position under the depressing force of the drive element.

Many existing drug delivery devices rely on small flexible plastic parts, typically thin and long plastic profiles, for locking the plunger rod in place. These profiles are subjected to constant loads during storage before use and are fragile parts of the design. By controlling the lateral movement of the plunger (rather than just the longitudinal movement of the plunger), the activation mechanism of the present invention can retain the drive element (such as a drive spring) and release the plunger with minimal force (such as the force with which the user presses the device to the injection site). This means that the activation element does not need to be made of a particularly strong material, unlike parts of conventional drug delivery device activation mechanisms. Furthermore, the latch mechanism requires only two rigid interlocking components.

The angled (i.e., non-perpendicular and non-parallel relative to the longitudinal axis) abutment between the first and second guide surfaces generates a normal reaction force having both a longitudinal component that resists the depressing force of the drive element (which acts in a direction parallel to the longitudinal axis of the plunger) and a lateral force that urges the plunger toward the activation element. This brings the resultant component of the driving element force acting on the activation element close to zero, allowing the activation element to move with minimal resistance.

Another advantage of the activation mechanism of the first aspect is that it does not require any rotation of the plunger. This means that the device can be assembled in a linear manner (i.e. without rotating any parts during assembly).

The depressing force is a biasing force that urges the plunger from an undepressed/retracted position to a depressed position (the plunger may initially be partially or fully retracted and the depressing force may act to urge the plunger toward a more depressed position). The depressing force acts (substantially) in a longitudinal direction (i.e. along the longitudinal axis of the plunger), although there may also be a relatively small transverse component of the depressing force.

The longitudinal axis of the plunger is the axis of the plunger that is parallel to the direction in which the plunger moves when the plunger is pressed into the barrel of the syringe (i.e. parallel to the depressing force provided by the drive element). The longitudinal axis of the plunger is substantially the same as the longitudinal axis of the barrel of the syringe.

The transverse direction is a direction perpendicular to the longitudinal axis of the plunger. Lateral displacement means a displacement having a non-negligible component in the lateral direction.

The syringe may be, for example, a prefilled syringe, and may be of any suitable size. Alternatively, the syringe may be a cartridge with a septum or any other drug container with a plunger. The tip of the syringe may optionally include a needle for delivering the drug into the patient. Alternatively, the tip of the syringe may be connected or connectable to a tube or the like.

The second guide surface may optionally be located on an interior surface of the housing or on a frame or other component received within the housing.

The first guide surface may optionally be located on a first guide element (such as a fin/lug) protruding radially/laterally from the plunger, and the second guide surface may be located on a second laterally protruding guide element within the housing (e.g., on an interior surface of the housing or on a frame or other component received within the housing).

Alternatively, the first guide surface may be located on a guide element (such as a fin/lug) protruding radially/laterally from the plunger, and the second guide surface may be located in a guide recess (or groove) (e.g., on an interior surface of the housing or on a frame or other component received within the housing). The guide recess may be shaped to receive a laterally protruding guide element.

Alternatively, the first guide surface may be located on a guide recess (or groove) in the plunger and the second guide surface may be located on a laterally protruding guide element (e.g. on an interior surface of the housing or on a frame or other component received within the housing). The guide recess may be shaped to receive a laterally protruding guide element.

The first guide surface may optionally be angled (i.e., non-perpendicular and non-parallel) relative to the longitudinal axis of the plunger. Additionally/alternatively, the second guide surface may be angled (i.e., non-perpendicular and non-parallel) with respect to the longitudinal axis of the plunger. Preferably, the angle of the first guide surface corresponds to the angle of the second guide surface.

The first and/or second guide surfaces may be planar, or one or both may be curved/non-planar.

Optionally, the activation element may be movable in a longitudinal direction within the housing. That is, movement of the activation element from the first position to the second position may include longitudinal movement of the activation element within the housing. Additionally or alternatively, movement of the activation element from the first position to the second position may include rotational movement and/or movement in a direction tangential to an outer surface of the plunger.

The activation element may be an activation plate.

Optionally, the activation element may include a hole or window shaped to receive a laterally protruding locking element (e.g., a laterally protruding fin or tab) of the plunger when the activation element is in the second position, and the laterally protruding locking element may abut the activation element in the first position.

Alternatively, the plunger may comprise a locking recess (or groove) arranged to receive the laterally protruding locking element of the activation element when the activation element is in the second position, and the laterally protruding locking element may abut the plunger in the first position.

The drive element may be any component suitable for exerting a longitudinal depressing force on the plunger.

Preferably, the drive element is a compression spring.

The drug delivery device may optionally further comprise a flexible conduit within or around the compression spring. The conduit prevents the compression spring from kinking or bending within the housing when the piston is depressed, but allows the plunger to move laterally (as opposed to the metal pins used with prior designs).

Alternatively, the driving element may be a piston. The piston may optionally be dampened and/or resettable.

Optionally, the drug delivery device may further comprise a movable needle guard arranged to protect the needle of the syringe. The needle guard may optionally include an activation element.

The lateral displacement of the plunger may include bending and/or pivoting of the plunger. For example, the plunger may pivot about a tip of the plunger received within a barrel of the syringe.

The drug delivery device may be an auto-injector, an injection pen, a patch pump or any other drug delivery device having a syringe driven by a drive element.

According to a second aspect of the present invention, there is provided an auto-injector cap comprising: a cap shell; and a clamping plate received in an opening in one side of the cap shell and arranged to clamp a Rigid Needle Shield (RNS) of a syringe barrel held within the auto-injector, wherein the clamping plate comprises a bore comprising a pair of opposing clamping surfaces configured to engage opposite sides of an outer surface of the RNS; and wherein the clamping plate is curved along a line bisecting the aperture such that each of the opposing clamping surfaces is angled toward the tip of the auto-injector cap.

One side of the housing extends between a first end of the cap shaped to receive the RNS and a second end of the cap opposite the first end. The tip of the auto-injector cap is located at the second end of the cap.

Conventional auto-injector caps use clamping elements such as metal tubing and star washers to clamp the RNS surface. However, these caps often require significant force to attach them, and when the cap is removed, the teeth of the star washer tend to bend/flip in an "over-center" manner, resulting in the cap being removed with the RNS (i.e., cap failure).

In contrast, having clamping surfaces on opposite sides of the plate that are curved along a line bisecting the bore allows the RNS of the prefilled syringe to be inserted into the cap with relatively little force (as the clamping surfaces are angled toward the tip of the auto injector cap) and with little risk of the clamping plate tipping.

Another advantage over conventional auto-injector caps is that the clamping plate may be made of a relatively thin/weak material. While clamping elements such as star washers rely on the stiffness of the metal to resist unwanted bending of the teeth, the curved shape of the clamping plate of the present invention means that the clamping surface naturally angles to clamp the RNS during cap removal without the need for curved raised teeth.

The clamping plate of the present invention can also be used to clamp RNSs of different diameters by adjusting the angle of bending, thereby reducing inventory costs and allowing for greater manufacturing tolerances. In contrast, conventional clamping mechanisms (such as star washers) are generally only suitable for a single RNS diameter and need to be manufactured with high precision.

Preferably, the gripping surface engages the outer surface of the RNS at a non-perpendicular angle relative to the longitudinal axis of the RNS. This non-perpendicular engagement allows the cap to be pushed onto the RNS with relatively little force while providing a high clamping force on the outer surface of the RNS.

Preferably, the clamping surfaces are positioned on opposite sides of the perimeter of the aperture.

The clamping plate is preferably formed of an elastic material and may optionally be held in the opening under strain (e.g., under compression) by abutment between the clamping plate and the inner surface of the opening. Under strain means that the resilient clamping plate is displaced from its equilibrium position such that the resilient biasing force urges it towards its original position. Holding the clamp plate under strain in the opening allows the clamp plate to be held in the opening by friction created between the clamp plate and the inner surface of the opening, which reduces the risk of the clamp plate falling out of the opening during sub-assembly transport and final assembly of the auto injector.

Optionally, the clamping plate may have an L-shaped profile. The clamping plate may be bent at an angle of (about) 90 degrees (i.e. right angle), or it may have a larger or smaller angle. The L-shaped arms may have (approximately) the same length or they may have different lengths.

Alternatively, the clamping plate may have a W-shaped profile. Having a W-shaped profile allows for a larger opening in one side of the cap, which makes the cap shell easier to manufacture and makes the cap easier to assemble.

Preferably, the clamping plate is bent at an angle of between 110 and 150 degrees, more preferably between 120 and 140 degrees, even more preferably between 125 and 135 degrees, and most preferably (about) 130 degrees along a line bisecting the hole. Bending at these angles means that the RNS can be easily inserted into the cap, but also ensures a sufficient clamping force between the RNS and the clamping plate.

Preferably, at least a portion of the opening has a profile that is angled to match the profile of the clamping element. Having a matching profile means that the opening supports the gripping surface during removal of the cap, which prevents the gripping element and/or gripping surface from tipping over and losing grip on the RNS.

The cap shell may optionally and advantageously be formed as a single molded component.

According to a third aspect of the present invention there is provided an auto-injector comprising the cap of the second aspect.

The autoinjector of the third aspect may optionally have any of the features of the first aspect of the invention, although such features are not required.

According to a fourth aspect of the present invention there is provided an automatic injector comprising: a housing; a needle guard movable between a retracted position and an extended position in which the needle guard is arranged to protect a needle of a syringe held within the housing; and a biasing spring arranged to bias the needle guard to an extended position, wherein the needle guard comprises a first latch element arranged to interface with a corresponding second latch element secured within the housing; wherein the auto-injector further comprises an activation element initially in a first position in which the activation element is positioned to block the second latch element and thereby prevent abutment between the first latch element and the second latch element; and wherein when the needle guard is moved from the extended position to the retracted position, abutment between the needle guard and the activation element causes the activation element to move from the first position to a second position in which the second latch element is exposed to the first latch element such that subsequent movement of the needle guard from the extended position to the retracted position is prevented by abutment between the first latch element and the second latch element.

In the extended position, a portion of the needle guard at least partially surrounds the tip of the needle. In the retracted position, the tip of the needle is exposed (i.e., not surrounded by a portion of the needle guard).

The needle guard activation mechanism of the fourth aspect requires fewer parts than existing designs and thus helps reduce waste. Furthermore, in existing designs, the needle guard is typically in a different position (i.e., there are multiple retracted positions) when on the cap than the position where the auto-injector is activated, and the "locked" position of the needle guard is different from the "cap removed" position (i.e., there are also multiple extended positions). Instead, the invention of the fourth aspect may use a single fully extended position and a single fully retracted position.

One problem with the multiple extended/retracted positions on existing devices is that the trigger position is typically very close to the active position, which may result in accidental activation, for example when the device is dropped. To overcome this problem, existing designs use complex locking mechanisms which increase the number of parts required in the device compared to the activation mechanism of the fourth aspect.

In addition, the activation mechanism of the fourth aspect may be activated solely by the energy stored in the metal spring, independent of the spring force from the bent plastic part. The plastic feature does not provide a long term spring force because the plastic will creep and mold to its storage position, thus the activation mechanism of the fourth aspect provides an auto-injector with an extended life.

Optionally, the automatic injector may further comprise a removable cap, wherein the needle guard is initially in the retracted position and is configured to move from the retracted position into the extended position under the influence of the biasing spring upon removal of the removable cap.

In existing designs, the needle guard is typically held in an extended position prior to removal of the cap. In contrast, the activation mechanism of the fourth aspect allows the cap to be applied when the needle guard is in the retracted position, which makes it easier for the cap to grip the RNS of the needle, as more of the RNS is exposed (which is particularly advantageous when the auto-injector of the fourth aspect is used in combination with the auto-injector cap of the second aspect). This may be achieved by inserting the first latch element into the housing of the auto-injector adjacent to (i.e. alongside) the activation element during assembly such that the first latch element does not engage the activation element until the needle guard extends when the cap is removed.

Preferably, the needle guard is able to hinge without bending, allowing the first latch element to engage with the second latch element.

The activation element may be the same activation element as in the first aspect of the invention, i.e. movement of the activation element from the first position to the second position may also activate a syringe plunger of an automatic injector. Alternatively, the activation element may be a separate component. The activation element may optionally be an activation plate.

Preferably, the first latch element is a longitudinal arm of the needle guard.

Optionally, the biasing spring may be further arranged to provide a lateral force on the longitudinal arm to bias the longitudinal arm towards the second latch element. This allows for improved engagement between the first and second latch elements, which reduces the risk of accidental retraction of the needle guard after the device has been used.

Preferably, the second latch element is located on an inner surface of the housing. Alternatively, the second latch element may be located on another element of the housing that is fixed relative to the syringe, for example on a support/frame or the like.

For example, the second latch element may be a recess or a protrusion within the housing.

The autoinjector used in the fourth aspect may have any of the features of the first and/or second aspects, although such features are not required.

According to a fifth aspect of the present invention there is provided a syringe retaining member for retaining a syringe in a drug delivery device, the syringe retaining member comprising: an annular collar; and a pair of opposing arms extending longitudinally from a distal side of the annular collar, each of the pair of opposing arms being pivotable relative to the collar about a respective pivot point, wherein each of the pair of opposing arms includes a shoulder portion distal of the respective pivot point such that the pair of opposing arms together provide a syringe abutment shoulder for engagement in a circumferential gap between a barrel of the syringe and a Rigid Needle Shield (RNS) of the syringe.

According to a sixth aspect of the present invention there is provided a syringe retaining member for retaining a syringe in a drug delivery device, the syringe retaining member comprising: an annular collar; and one or more support arms extending longitudinally from a distal side of the annular collar, each of the one or more support arms being pivotable relative to the collar about a respective pivot point, wherein each of the one or more support arms includes a shoulder portion distal of the respective pivot point that provides a syringe abutment shoulder for engagement in a circumferential gap of a barrel of the syringe between a Rigid Needle Shield (RNS) of the syringe.

In existing drug delivery devices, the syringe carrier and front end piece are typically assembled during final assembly, where the syringe must be assembled into the carrier before being pushed into the front subassembly. In the syringe holding member of the fifth and sixth aspects, the need for a separate syringe carrier is eliminated by means of the arm pivoting: during assembly, the arms are manually hinged apart to allow insertion of the syringe (i.e., the syringe cannot be inserted between the arms if the arms are not held apart).

Having the shoulder portion (and thus the syringe barrel abutting the shoulder) distal to the pivot point creates a self-locking effect on the syringe barrel: when a load is placed on the syringe plunger, the force acting on the syringe abutment shoulder causes the arms to grip the syringe more tightly than to force them apart. This means that no external collar is required, as compared to prior designs (e.g. designs in which the pivot point is distal to the shoulder portion).

As known to those skilled in the art, the tip of the syringe is positioned towards the proximal end of the drug delivery device (i.e., the end with the cap) and the distal end of the drug delivery device is the opposite end of the drug delivery device (i.e., the end distal from the syringe and the cap of the device). The distal side of the annular collar is the side of the collar that is positioned towards the distal end of the drug delivery device once the drug delivery device is assembled.

Preferably, when the syringe is inserted into the syringe retaining member, the abutment surface of the syringe (e.g., on the outer surface of the neck of the syringe) abuts a respective engagement surface of the syringe abutment shoulder of each respective support arm, wherein the respective engagement surface is positioned proximal of a line extending through the respective pivot point of the respective support arm that is perpendicular to a tangent to the abutment surface (or, if the abutment surface is flat, to the abutment surface in which the respective engagement surface abuts the abutment surface). In other words, the point on the abutment surface where the corresponding engagement surface abuts the abutment surface is located at a proximal position on the tangent to the straight line (i.e. closer to the needle end of the assembled auto-injector) (instead of being located proximally, it is also effectively said that it is located radially inwards).

Positioning the engagement surface at the proximal end of a straight line extending through the pivot point perpendicular to the tangent of the abutment surface ensures that the support arm pivots radially inward when a load is applied to the syringe plunger, thereby achieving a self-locking effect without the need for any collar or the like around the support arm.

The syringe abutment shoulder may optionally be formed by an inwardly projecting syringe boss on each of the arms.

Preferably, the opening in the annular collar is shaped to receive a needle guard.

Preferably, the outer surface of each of the pair of opposing arms includes a first locking element configured to interface with a corresponding second locking element on the housing or syringe carrier of the auto-injector to prevent removal of the syringe retaining member from the housing. Once assembled, the housing acts as an outer tube around the syringe retaining member, pushing a pair of opposing arms onto the syringe and preventing the syringe from moving.

Preferably, the outer surface of each of the support arms includes a first locking element configured to interface with a corresponding second locking element on the housing or syringe carrier of the auto-injector to prevent removal of the syringe retaining member from the housing. Once assembled, the housing acts as an outer tube around the syringe retaining member pushing the support arm onto the syringe and preventing the syringe from moving.

Preferably, the barrel of the syringe provides a radially outward reaction force that resists inward flexing of the opposing arms when the syringe is received within the syringe retaining member.

Optionally, the drug delivery device may be an auto-injector, a patch pump or an injection pen.

The one or more support arms may include a pair of opposing arms. The one or more support arms may also comprise more than two arms (e.g. three arms), which are preferably arranged equidistantly around the distal side of the annular collar.

According to a seventh aspect of the present invention there is provided a drug delivery device comprising the syringe retaining member of the fifth or sixth aspect.

The drug delivery device of the seventh aspect may optionally have any of the features of the first, second and/or fourth aspects of the invention, although such features are not required.

According to an eighth aspect of the present invention, there is provided an automatic injector cap comprising: a cap shell; and a clamping plate received in an opening in one side of the cap housing and arranged to clamp a rigid needle shield of a syringe held within the auto-injector, wherein the clamping plate comprises a bore comprising a pair of opposing clamping surfaces configured to engage opposing sides of an outer surface of the rigid needle shield; and wherein the clamping plate is curved along a line bisecting the aperture such that each of the opposing clamping surfaces is angled toward the tip of the auto-injector cap.

According to a ninth aspect of the present invention, there is provided an automatic injector comprising: a housing; a needle guard movable between a retracted position and an extended position in which the needle guard is arranged to protect a needle of a syringe held within the housing; and a biasing element arranged to bias the needle guard to an extended position, wherein the needle guard comprises a first latch element arranged to interface with a corresponding second latch element secured within the housing; wherein the auto-injector further comprises an activation element initially in a first position in which the activation element is positioned to block the second latch element and thereby prevent abutment between the first latch element and the second latch element; and wherein when the needle guard is moved from the extended position to the retracted position, abutment between the needle guard and the activation element causes the activation element to move from the first position to a second position in which the second latch element is exposed to the first latch element such that subsequent movement of the needle guard from the extended position to the retracted position is prevented by abutment between the first latch element and the second latch element.

Drawings

Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which:

FIG. 1 shows a side view of an auto-injector;

FIG. 2 shows a cross-sectional view of an auto-injector;

FIG. 3 shows an exploded view of the components of the automatic injector;

FIG. 4 shows a cross-sectional view of an activation mechanism of an automatic injector;

figures 5a-5d show cross-sectional views of an auto-injector during different states of drug delivery;

FIGS. 6a-6c illustrate activation of an auto-injector;

FIG. 7 is a side view of an injection pen;

FIG. 8 shows an auto-injector cap;

FIG. 9 shows a side view of an auto-injector cap;

FIGS. 10a-10c show alternative views of an auto-injector cap;

FIGS. 11a-11e illustrate a shield activation mechanism for an automatic injector;

FIG. 12 shows a side view of the shield activation mechanism;

13a and 13b illustrate a syringe retaining member of an automatic injector;

14a-14f illustrate how the syringe retaining member is assembled with the syringe and needle guard;

15a and 15b illustrate engagement between the syringe retaining member and the syringe and needle guard;

FIG. 16 shows a cross-sectional view of the syringe retaining member;

FIG. 17 shows an alternative cross-sectional view of the syringe retaining member; and

Fig. 18 shows a simplified illustration of the geometry of the syringe retaining member.

Detailed Description

Fig. 1 shows a drug delivery device in the form of an auto-injector 100 having a cap 101 and a housing 102. As shown in fig. 2, the cap 101 of the automatic injector 100 has a Rigid Needle Shield (RNS) gripping element 103, and the housing 102 contains a needle guard 104, a syringe retaining member 105, a pre-filled syringe (PFS) 106 (pre-filled with the drug to be administered), an activation element in the form of an activation plate 107, a biasing spring 108, a plunger 109 (which may also be referred to as a plunger rod), and a drive element in the form of a drive spring 110.

The components of the auto-injector are shown in more detail in the exploded view of fig. 3, wherein the flexible catheter 111 can also be seen.

The housing 102 may be any container or housing suitable for containing the components of the automatic injector 100, and may be partially or completely enclosed. To allow visual inspection of the components of the automatic injector 100, the housing 102 may be partially or completely transparent. Alternatively, the housing 102 may be translucent or opaque, for example if a photosensitive drug is desired. The housing 102 may also have one or more windows through which components of the drug delivery device may be viewed, which may be formed as an opening or transparent portion of the housing 102.

The RNS gripping element 103 acts to grip the RNS of the PFS106 such that the RNS is removed with the cap 101 when the user separates the cap 101 from the housing 102 (e.g., immediately prior to administration of a drug using the automatic injector 100).

The PFS106 may be any suitable device having a barrel and a plunger. The drug stored in the PFS106 may be in liquid form, or the drug may alternatively be in another form, such as a powder that is mixed with a liquid prior to injection.

A syringe retaining member 105 retains needle guard 104 and PFS106 within housing 102. The needle guard 104 is longitudinally movable within the housing 102. In its initial position (as shown in fig. 1 and 2), needle guard 104 substantially encloses the needle of PFS106 and serves both to activate auto-injector 100 when pressed against the skin and to prevent exposure of the needle of PFS106 after use.

The biasing spring 108 serves a dual purpose: providing a retaining force on the PFS106 (e.g., on a flange of the PFS 106) to prevent the PFS106 from moving back into the housing 102 during injection; and provides a restoring force on needle guard 104. Biasing spring 108 is shown as being formed of a resilient metal plate, but other mechanisms may be used instead (such as a plastic biasing spring, or a pair of springs or other biasing elements acting alone on PFS106 and needle guard 104).

The plunger 109 is used to drive the medication out of the PFS106 under the force of the drive spring 110. Although the drive spring 110 is shown as a compression spring, it may be replaced with an alternative biasing element/drive element (such as a piston). The flexible tube 111 surrounds at least a portion of the drive spring 110 and acts to prevent the drive spring 110 from bending within the housing when the plunger 109 is driven. The flexible tube 111 may alternatively be positioned within the drive spring 110 or replaced by a flexible pin within the drive spring 110.

The activation plate 107 prevents movement of the plunger 109 until the drug is to be delivered.

Activating mechanism

The activation mechanism of the automatic injector 100 will now be described in more detail. While the activation mechanism will be described primarily with respect to an auto-injector, it should be understood that the activation mechanism may also be incorporated into other automated drug delivery devices, such as patch pumps and injection pens.

The components of the activation mechanism are shown in detail in fig. 4. As previously described, the activation plate 107 prevents movement of the plunger 109 until the drug is to be delivered. Conventional activation mechanisms resist longitudinal movement of the plunger 109 (and thus act directly against the compression force of the drive spring 110), but the illustrated activation mechanisms resist lateral movement of the plunger 109 (i.e., movement of the plunger 109 in a direction perpendicular to the longitudinal extent of the plunger 109) in contrast. As a result, the activation plate 107 need only exert a relatively low stopping force to stop movement of the plunger 109. Conventional activation mechanisms typically resist longitudinal movement by a flexible locking member. The member is part of a load chain by which the plunger rod is held in place. The final design requires flexible but strong components. They are typically locked in place by another component that resists lateral movement of the bending member.

As seen in fig. 4, which shows the initial state of the automatic injector 100, the activation plate 107 initially abuts against a laterally projecting locking fin 113 (also referred to as a laterally projecting locking element) on the plunger 109. The abutment between the activation plate 107 and the locking fin 113 is in a direction substantially perpendicular to the longitudinal axis of the plunger 109 (i.e. in a transverse direction) and thus prevents transverse movement of the plunger 109 within the housing 102.

The activation plate 107 has windows (or holes) 112 shaped to receive locking fins 113. As discussed in more detail below, when the needle guard 104 is pressed against the patient's skin, this causes the activation plate 107 to move longitudinally relative to the plunger 109 and thereby align the window 112 with the locking fin 113 so that the locking fin 113 can move into the window 112.

While the illustrated activation plate 107 is preferably made of metal, it may be made of other materials such as plastic. Additionally, the activation plate 107 may be integrated into the needle guard 104 instead of being a discrete component. Furthermore, the configuration may be reversed such that the plunger includes a window or recess shaped to receive a laterally protruding locking element on the activation element such that movement of the activation element aligns the window/recess/groove with the laterally protruding locking element.

To prevent longitudinal movement of the plunger 109 until the auto-injector 100 is activated, a first guide surface on the leading edge of the laterally raised guide fin 115 abuts a second guide surface on a laterally raised guide tab 114 (shown in fig. 5a-5 d) within the housing 102. Although the guide tab 114 is shown on the housing 102, it should be understood that the second guide surface could equally be on another element within the housing 102, such as a frame or the like. Similarly, the configuration may be modified such that the second guide surface is located on a recess in the housing, or such that the plunger includes a guide recess shaped to receive a laterally protruding guide element in the housing 101 (e.g., on the housing or another element in the housing, such as on a frame or the like).

The first guide surface abuts the second guide surface at a non-perpendicular (and non-parallel) angle relative to the longitudinal axis of the plunger 109. This produces a normal reaction force having both a longitudinal component against the compression force of the drive spring 110 and a lateral force pushing the plunger 109 towards the activation plate 107. As discussed above, the lateral abutment between the locking fin 113 and the activation plate 107 prevents lateral movement of the plunger 109 such that the plunger 109 initially remains balanced under the combination of the force of the drive spring 109 and the normal reaction forces between the first and second guide surfaces and between the locking fin 113 and the activation plate 107.

In the illustrated auto-injector 100, the non-perpendicular abutment angle is achieved by shaping the angled leading edge (first guide surface) on the guide fin 115 to abut the corresponding angled edge (second guide surface) in the guide tab 114. However, the first and second guide surfaces do not necessarily need to have corresponding angles: for example, one surface may be angled with respect to the longitudinal axis of the plunger 109, while the other surface may be perpendicular to the longitudinal axis of the plunger 109, so long as the relative angle therebetween is not perpendicular to the longitudinal axis of the plunger 109.

While the locking fins 113 and guide fins 115 are disposed at the distal end of the plunger 109 (i.e., away from the tip of the PFS 106), one or both of them may alternatively be positioned elsewhere along the longitudinal extension, e.g., closer to the barrel of the PFS 106. The activation plate 107 and/or the guide projection 114 will have to be repositioned accordingly. Similarly, while both locking fins 113 and guide fins 115 are fin-shaped, they may alternatively have other shapes and are more generally referred to as laterally raised locking elements and laterally raised guide elements, respectively (and windows 112 and guide tabs 114 may be shaped accordingly).

The operation of the activation mechanism will now be described in more detail with reference to fig. 5a-5 d.

Fig. 5a shows the auto-injector 100 in an initial state (i.e. before activation) with the cap 101 removed. Removal of the cap 101 causes removal of the RNS of the PFS106, thereby exposing the needle 116 of the PFS, which is surrounded by the end of the needle guard 104 in fig. 5a and 5 d.

In this initial state, the plunger 109 is retracted from the barrel of the PFS106, and the drive spring 110 is in a compressed state, and thus applies a depressing force to the plunger 109.

To activate the auto-injector 100, the needle end of the auto-injector 100 is pressed against the patient's skin. Abutment between the needle guard 104 and the patient's skin pushes the needle guard 104 longitudinally into the housing 102 into the condition shown in fig. 5b, while the needle 116 pierces the surface of the patient's skin. When the needle guard 104 is retracted longitudinally into the housing 102, the abutment between the activation plate 107 and the arm 117 of the needle guard 104 causes longitudinal movement of the activation plate 107 from an initial locking position (wherein the activation plate 107 laterally abuts the locking fins 113 of the plunger 109) to an activated position (wherein the windows 112 of the activation plate 107 are aligned with the locking fins 113 of the plunger 109).

As discussed in more detail below with reference to fig. 6a-6c, movement of the activation plate 107 to the activated position releases the plunger 109, allowing the plunger 109 to be driven into the PFS106 under the restoring force of the compression spring 110 into the position shown in fig. 5 c. This depression of the plunger 109 causes at least some of the drug in the PFS106 to be expelled from the PFS106 and injected into the patient via the needle 116. The plunger 109 may optionally have a recess on its outer surface that interacts with the biasing spring 108 to provide audible feedback when the plunger 109 is depressed. In addition, a track for guiding the plunger 109 may be provided in the housing 102.

Once the drug has been delivered, the auto-injector 100 is removed from the patient's skin. The restoring force of the biasing spring 108 then forces the end of the needle guard 104 to extend from the housing 102, as shown in fig. 5d, thereby enclosing the needle 116. The needle guard 104 is preferably locked in this position, as discussed below, to prevent further use and injury from accidental contact pins 116. The automatic injector 100 may then be discarded, for example, in a sharps container.

The process of releasing the plunger 109 is shown in more detail in fig. 6a-6 c.

Fig. 6a shows the auto-injector 100 in a momentary state, wherein the activation plate 107 has been displaced by the needle guard 104 in order to align the window 112 of the activation plate 107 with the locking fin 113 of the plunger 109. This is the same as the configuration shown in fig. 5 b.

The alignment between the window 112 and the locking fin 113 eliminates the lateral abutment forces that previously prevented lateral movement of the distal end of the plunger 109 (i.e., the end of the plunger 109 distal to the injection end/needle 116). As discussed above, the normal reaction force between the first guide surface (on the guide fin 115 of the plunger 109) and the second guide surface (on the guide tab 114) has a lateral component that pushes the distal end of the plunger 109 toward the activation plate 107.

The movement of the activation plate 107 thus eliminates the balance between the plunger 109 and the activation plate 107, which causes the distal end of the plunger 109 to move laterally into the position shown in fig. 6b as the locking fin 113 enters the window 112 in the activation plate 107. The guide fins 115 simultaneously slide against the guide tabs 114, causing a slight longitudinal movement of the plunger 109 into the barrel of the PFS106 in addition to the lateral movement of the plunger 109.

In fig. 6b, the lateral movement of the plunger 109 is manifested as a pivoting of the plunger 109 about the tip (proximal end) of the plunger 109 received within the barrel of the PFS 106. Lateral movement may alternatively be achieved by bending or flexing of the plunger 109.

The lateral movement of the plunger 109 continues until the first guide surface disengages from the second guide surface as the guide fin 115 slides out of the guide tab 114. At this point, the lateral and longitudinal normal reaction forces due to abutment between the first and second guide surfaces are removed and the plunger 109 is free to move only under the force of the drive spring 110 which acts longitudinally to depress the plunger 109 into the barrel of the PFS106, thereby expelling the drug from the PFS106 through the needle 116, as described above with respect to fig. 5a-5 d.

The illustrated auto-injector 100 has no coaxial components other than the drive spring 110 and plunger 109, which allows for inspection of the internal mechanism (e.g., through the transparent housing 102) after assembly and also allows the user to view progress during injection, as the plunger 109 can be seen to move to its final position without being obscured by the needle guard 104.

As mentioned above, the activation mechanism may be integrated into other drug delivery devices, such as patch pumps and injection pens. An exemplary injection pen 700 is shown in fig. 7. The injection pen has a housing 701, a PFS 702, a plunger 703, an activation plate 704 with a plurality of windows (not visible), a laterally protruding locking fin 705, a plurality of guiding recesses 706a-706d, a laterally protruding guiding fin 707 and an activation button 708. Alternative arrangements are envisaged in which the window is an open "U" shape.

When the user actuates the activation button 708, causing the window on the activation plate 704 to align with the locking fin 705 in the same manner as the auto-injector described above, the injection pen 700 is activated. Having multiple windows and multiple guiding recesses 706a-706d means that the injection pen 700 can be used to provide multiple doses of medicament, where each dose is administered using the same activation mechanism. Guide fins 707 will be received in each guide recess in turn and will only be able to move to the next guide recess when the injection pen 700 is activated.

It is contemplated that the auto-injector 100 described above may also be modified to have multiple windows on the activation plate 107 and/or to have multiple guide recesses so that multiple doses of medication may be administered in the same manner as the injection pen 700 in fig. 7.

While the illustrated activation plates 107 and 704 move longitudinally within the housings 102 and 701, respectively, the activation plates may alternatively be replaced by other activation elements (such as tubes surrounding the outside of the plunger) that move, for example, tangentially or in any other direction relative to the surface of the plunger, and/or rotate within the housing to move from a first position (in which the activation elements prevent lateral movement of the plunger) to a second position (in which lateral movement of the plunger is permitted). Importantly, the activation element initially provides a force that resists lateral movement of the plunger in a lateral direction and upon activation moves to a second (activated) position in which the plunger is laterally movable.

Automatic injector cap

Fig. 8 shows the cap 101 of the automatic injector 100 in more detail. As described above, the cap 101 has gripping elements 103 that act to grip the RNS of the PFS106 to ensure that the RNS is removed from the PFS106 when the cap 101 is separated from the housing 102.

The cap 101 itself comprises a cap shell 801 having an opening 802 on its side shaped to receive the clamping element 103. The clamping element 103 is formed as a plate with holes 803 and may alternatively be referred to as a clamping plate. Clamping element 103 is curved along a line approximately bisecting aperture 803 (i.e., a line approximately centered between clamping surfaces 804 described below). The angle formed by the bend may vary depending on the size and configuration of cap 101, but is less than 180 degrees (no bend at all) and greater than 0 degrees (full bend). Preferably, the angle of the bend is about 130 degrees.

Clamping surfaces 804 are positioned on opposite sides of the perimeter of aperture 803 (i.e., symmetrical about a line bisecting aperture 803). The illustrated gripping surface 804 is formed as a protrusion extending from the perimeter of the aperture 803, although non-protruding surfaces are also contemplated.

Gripping surfaces 804 are positioned to grip the RNS 805 of the PFS106 on opposite sides of the RNS 805. The illustrated RNS 805 has raised ridges that improve engagement between the gripping surface 804 and the RNS 805, but these are optional features and the gripping surface 804 is also capable of gripping a smooth RNS (i.e., without raised ridges).

The illustrated clamping element 103 is also bent on opposite sides of the aperture 803 to form a W shape with wings 806 on either side. The W-shaped profile of the clamping element 103 allows the opening 802 to be larger, which makes the cap shell 801 easier to manufacture and makes the cap 101 easier to assemble. However, the clamping element 103 may alternatively be formed with fewer or more bends, such as a single bend (e.g., having an L-shaped profile or the like) bisecting the aperture 803.

A side view of cap 101 is shown in fig. 9. The opening 802 has a curved/angled profile similar to the gripping element 103 (i.e., at least a portion of the opening 802 has a profile that matches the profile of the gripping element 103), which facilitates insertion of the gripping element 103 into the opening 802 and also provides structural support for the gripping element 103 during removal of the cap 101. In the example shown, the tips of wings 806 of the clamping element 103 abut against the inner surface of the opening 802, thereby preventing longitudinal movement of the clamping element 103 relative to the cap 101.

The clamping element 103 is preferably made of an elastic material and may optionally be inserted into the opening 802 under strain (e.g., under compression of the wings 806 pressing against each other) such that the elastic restoring force of the clamping element causes abutment between the clamping element 103 and the inner surface of the opening 802, thereby retaining the clamping element 103 within the opening 802 by friction. This allows the clamping element 103 to be inserted into the cap 101 prior to full assembly of the automatic injector 100 without risk of the clamping element falling out of the opening 802.

The curved nature of the gripping element 103 causes the gripping surface 804 to be angled toward the tip of the auto-injector cap (i.e., away from the end of the cap that receives the RNS 805). The angled gripping surface 804 engages the outer surface of the RNS at a non-perpendicular angle relative to the longitudinal axis of the RNS and thus allows the RNS 805 to be inserted into the cap 101 with relatively little force while providing an extremely strong gripping force on the outer surface of the 805, which reduces the risk of the cap 101 separating from the RNS 805 when the cap is removed from the auto injector 100.

Alternative cross-sectional views of cap 101 are shown in fig. 10a-10 c.

Activating logic

Fig. 11a-11e illustrate how the activation plate 107 may also be used to control the position of the needle guard 104 to prevent insertion (into the skin) or exposure of the needle 116 after the device has been used.

Fig. 11a shows the auto-injector 100 in an initial configuration, e.g. with a cap 101 attached. Needle guard 104 is held in the retracted position by cap 101. The illustrated activation plate 107 has a stepped slot that allows the needle guard arm 1101 of the needle guard 104 to be inserted beyond the step 1102 during assembly of the automatic injector 100. As can be seen in fig. 11a, the needle guard arm 1101 is initially bent to an unbalanced position by abutting against the activation plate 107. Alternative arrangements are contemplated in which needle arm 1101 is inserted along activation plate 107 (or another activation element) rather than into a stepped slot.

When cap 101 is removed, needle guard 104 moves to the extended position under the force of biasing spring 108, as shown in fig. 11b, and the elasticity of needle guard arm 1101 laterally aligns needle guard arm 1101 with the step.

As shown in fig. 11c, when the needle guard 104 is subsequently retracted (e.g., when the automatic injector 100 is pressed against the skin of a user), the end of the needle guard arm 1101 abuts the step 1102. This abutment between the needle guard arm 1101 and the step 1102 causes a longitudinal displacement of the activation plate 107, which exposes a latch element 1201 (visible in fig. 12) on a surface within the housing.

The displacement of the activation plate 107 also triggers the activation of the plunger 109, as discussed above and shown in fig. 11 d.

When the automatic injector 100 is removed from the user's skin, the needle guard 104 is again extended into the position shown in fig. 11e under the force of the biasing spring 108. Needle guard 104 is then prevented from further retraction into the retracted position, i.e. needle guard 104 is locked in the fully extended position, by abutment between needle guard arm 1101 (which acts as a first latching element) and latching element 1201 within the housing (which acts as a second latching element).

The biasing spring 108 also provides a laterally outward force to the needle guard arm 1101 that acts to guide the needle guard arm 1101 into the latch member 1201 and thereby ensure that the needle guard arm 1101 is engaged with the latch member 1201.

Although not required, the second needle guard arm 1101 can also engage with another latch member 1201 on the opposite side of the housing 102, as shown in fig. 12. Engagement between the second needle guard arm 1101 and the other latch member 1201 may also be assisted by the biasing spring 108 as described above.

Although the latch element 1201 shown in fig. 12 is in the form of a boss that abuts the needle guard arm 1101, the latch element 1201 may be replaced by, for example, a recess that serves the same function as the boss latch element 1201 (i.e., abuts the needle guard arm).

Although the activation plate 107 is shown for the dual purpose of activating the plunger 109 and controlling the position of the needle guard 104, the activation plate 107 may be replaced with one of a plurality of activation elements, each of which serves only one of these functions, i.e. a single activation element for activating the plunger 109 and/or a single activation element for controlling the position of the needle guard 104.

Syringe holding member

The syringe retaining member 105 is shown in more detail in fig. 13a and 13 b. The syringe retaining member 105 has an annular collar 1301 with a pair of opposing arms 1302 (also referred to as support arms) extending longitudinally from the distal side of the collar (i.e., the side of the collar at the distal end of the syringe needle when the automatic injector 100 is assembled). While the illustrated embodiment has two support arms, it should be understood that alternative embodiments having three or more arms are contemplated, preferably wherein the arms are equally spaced about the distal side of annular collar 1301. Alternatively, embodiments with a single support arm are also conceivable. Such embodiments may optionally further include a static (i.e., non-pivoting) support element on the opposite side of the collar from the single support arm.

Each opposing arm 1302 may pivot/articulate about a pivot point 1303 formed as a narrowed portion of each opposing arm 1302 in the illustrated syringe retaining member 105. The outer surface of the syringe retaining member 105 has a plurality of locking elements 1304 (on opposing arms 1302) arranged to interface with corresponding locking elements on the inner surface of the housing 102. For example, the locking element 1304 on the syringe retaining member 105 may be a plurality of protrusions/ledges (or vice versa) shaped to interface with a corresponding plurality of detents on the housing 102.

Figures 14a-14f illustrate the assembly of the syringe retaining member 105 with the needle guard 104 and PFS 106. As shown in fig. 14a, cap 101, syringe retaining member 105, needle guard 104 and PFS106 are initially separated.

During assembly of auto-injector 100, arm 1302 of syringe retaining member 105 is manually pivoted outwardly and needle guard 104 is inserted into a hole (not visible) in annular collar 1301, as shown in fig. 14 b. Once needle guard 104 is fully inserted, arms 1302 may return to their original position as shown in FIG. 14 c.

Next, as shown in fig. 14d, the cap 101 is placed against the syringe retaining member 105. The opposing arms 1302 are then manually pivoted outwardly as shown in fig. 14e to allow the PFS106 to be inserted into the syringe retaining member 105 and needle guard 104 and the RNS of the PFS106 to be pushed into the cap 101. Once in place, the opposing arms 1302 pivot back to their original positions as shown in FIG. 14 f.

Turning to fig. 15a and 15b, which show cross-sectional views of syringe retaining member 105, PFS106 is retained by shoulder portions 1501 raised from the inner surfaces of opposing arms 1302 distal to pivot point 1303. The shoulder portion 1501 is shaped to engage the shoulder of the PFS106 in the circumferential gap between the RNS 805 and the barrel of the PFS 106. Shoulder portions 1501 provide a reaction force that resists the longitudinal force applied to PFS106 by biasing spring 108 and prevents PFS106 from backing out of the housing.

The opposing arms 1302 of the syringe retaining member 105 are additionally shaped to abut against the raised walls 1502 in the outer surface of the needle guard 104. This abutment between the arms 1302 and the raised walls 1502 prevents the needle guard 104 from falling out of the housing 102.

Once assembled, the barrel of PFS106 provides a radially outward reaction force that resists inward flexing of opposing arms 1302. This helps to retain the syringe retaining member 105 in the housing 102 by preventing the locking element 1304 from disengaging from a corresponding locking element on the inner surface of the housing 102. Housing 102 acts to push opposing arms 1302 inward, drawing all components tightly together and securing PFS106 from movement. The syringe retaining member may optionally be provided with a label package to resist bending and provide tamper evidence.

Fig. 16 and 17 show alternative cross-sectional views of the syringe retaining member 105 and PFS106 with and without needle guard 104, respectively.

While syringe retaining member 105 is shown with two opposing arms 1302, alternatives are contemplated in which there are more arms, such as three, four, or more opposing arms. When the number of opposing arms is an odd number, the arms will not directly oppose each other, but they will still oppose each other in the sense that they are arranged on opposite sides of the syringe retaining member in a manner that provides a net counter-balance force.

Having the shoulder portion distal to the pivot point creates a self-locking effect on the syringe barrel: when a load is placed on the syringe plunger, the force acting on the syringe abutment shoulder causes the arms to grip the syringe more tightly than to force them apart. To ensure that the support arms pivot radially inwardly when a load is applied to the syringe plunger, the engagement surface of each arm is preferably positioned proximal to a line extending through the pivot point of each support arm, perpendicular to the tangent of the syringe surface, with the syringe abutting the arm. This relationship is shown in fig. 18, fig. 18 being a simplified illustration of the geometry of arm 1302. As shown in fig. 18, PFS106 abuts left arm 1302 at point 1801. The tangent to the surface of PFS106 at point 1801 is shown by dashed line 1802. It can be seen that point 1801 is located proximally (and radially inward) of line 1803 passing through pivot point 1303, perpendicular to tangent 1802 (in other words, point 1801 is located proximally relative to line 1803 and radially inward along tangent 1802).

Although the syringe retaining member 105 has been described with respect to an auto-injector, it may also be used to retain a syringe in other drug delivery devices, such as an injection pen, with or without the needle guard 104.

Other examples and applications

It should be understood that the illustrated devices disclosed herein are merely exemplary and that the devices may potentially have additional or fewer features while still falling within the scope of the appended claims. Also, the shape and size of the components of the device may vary from that shown.

In addition, unless otherwise indicated, the order in which the method steps are presented is merely exemplary, and one skilled in the art will recognize that the steps of the methods disclosed herein may be performed in a different order (unless technically infeasible) and that additional or fewer steps may also be performed.

Claims (26)

1. A drug delivery device, comprising:

A housing;

A syringe received within the housing and including a plunger, wherein the plunger includes a first guide surface arranged to abut a second guide surface within the housing at a non-perpendicular angle relative to a longitudinal axis of the plunger;

a drive element arranged to apply a depressing force to the plunger; and

An activation element movable between a first position in which the activation element is arranged to inhibit lateral movement of the plunger within the housing and a second position in which the activation element is arranged to permit lateral movement of at least a portion of the plunger within the housing,

Wherein when the activation element is displaced from the first position to the second position, abutment between the first guide surface and the second guide surface causes lateral displacement of the at least a portion of the plunger due to the depressing force of the drive element, releasing the plunger to move from an undeployed position to a depressed position under the depressing force of the drive element.

2. The drug delivery device of claim 1, wherein the plunger comprises a first laterally protruding guide element comprising the first guide surface, and wherein the second guide surface is located on a second laterally protruding guide element.

3. The drug delivery device of claim 1, wherein the plunger comprises a laterally protruding guide element comprising the first guide surface, and wherein the second guide surface is located in a guide recess arranged to receive the laterally protruding guide element.

4. The drug delivery device of claim 1, wherein the second guiding surface is located on a laterally protruding guiding element, and wherein the plunger comprises a guiding recess arranged to receive the laterally protruding guiding element, the guiding recess comprising the first guiding surface.

5. A drug delivery device according to any preceding claim, wherein the activation element is movable in a longitudinal direction.

6. A drug delivery device according to any preceding claim, wherein the activation element is rotatable.

7. A drug delivery device according to any preceding claim, wherein the activation element is movable in a direction tangential to an outer surface of the plunger.

8. A drug delivery device according to any preceding claim, wherein the activation element comprises an aperture shaped to receive a laterally protruding locking element of the plunger when the activation element is in the second position, and wherein the laterally protruding locking element abuts the activation element in the first position.

9. The drug delivery device of any one of claims 1 to 7, wherein the plunger comprises a locking recess shaped to receive a laterally protruding locking element of the activation element when the activation element is in the second position, and wherein the laterally protruding locking element abuts the plunger in the first position.

10. A drug delivery device according to any preceding claim, wherein the drive element is a compression spring.

11. The drug delivery device of claim 10, further comprising a flexible conduit within or around the compression spring.

12. The drug delivery device of any one of claims 1 to 9, wherein the drive element is a piston.

13. A drug delivery device according to any preceding claim, further comprising a movable needle guard arranged to protect a needle coupled to the tip of the syringe, wherein the needle guard comprises the activation element.

14. A drug delivery device according to any preceding claim, wherein the lateral displacement comprises bending and/or pivoting of the plunger.

15. A drug delivery device according to any preceding claim, wherein the drug delivery device is an auto-injector, an injection pen or a patch pump.

16. A syringe retaining member for retaining a syringe in a drug delivery device, the syringe retaining member comprising:

an annular collar; and, a step of, in the first embodiment,

One or more support arms extending longitudinally from a distal side of the annular collar, each of the one or more support arms being pivotable relative to the collar about a respective pivot point,

Wherein each of the one or more support arms includes a shoulder portion distal to the respective pivot point, the shoulder portion providing a syringe abutment shoulder for engagement in a circumferential gap between a barrel of the syringe and a rigid needle shield of the syringe.

17. The syringe retaining member of claim 16, wherein an abutment surface of the syringe abuts a respective engagement surface of the syringe abutment shoulder of each respective support arm when a syringe is inserted into the syringe retaining member, and wherein the respective engagement surface is positioned proximal of a line extending through the respective pivot point of the respective support arm that is perpendicular to a tangent line of the abutment surface, wherein the respective engagement surface abuts the abutment surface.

18. The syringe retaining member of claim 16 or claim 17, wherein the syringe abutment shoulder is formed by an inwardly projecting syringe boss on each support arm.

19. The syringe retaining member of any of claims 16-18, wherein the opening in the annular collar is shaped to receive a needle guard.

20. The syringe retaining member of any of claims 16-19, wherein an outer surface of each of the support arms includes a first locking element configured to interface with a corresponding second locking element on a housing or syringe carrier of the auto-injector to prevent removal of the syringe retaining member from the housing.

21. The syringe retaining member of any of claims 16-20, wherein a barrel of the syringe provides a radially outward reaction force that resists inward bending of the support arm when the syringe is received within the syringe retaining member.

22. The syringe retaining member of any of claims 16-21, wherein the drug delivery device is an auto-injector, a patch pump, or an injection pen.

23. The syringe retaining member of any of claims 16-22, wherein the one or more support arms comprise a pair of opposing arms.

24. A drug delivery device comprising a syringe retaining member according to any of claims 16 to 23.

25. An auto-injector cap, comprising:

A cap shell; and

A clamping plate received in an opening in one side of the cap housing and arranged to clamp a rigid needle shield of a syringe barrel held within the automatic injector,

Wherein the grip plate comprises a hole comprising a pair of opposing grip surfaces configured to engage opposite sides of an outer surface of the rigid needle shield; and

Wherein the clamping plate is curved along a line bisecting the aperture such that each of the opposing clamping surfaces is angled toward a tip of the auto-injector cap.

26. An automatic injector, comprising:

A housing;

a needle guard movable between a retracted position and an extended position in which the needle guard is arranged to protect a needle of a syringe held within the housing; and

A biasing element arranged to bias the needle guard into the extended position,

Wherein the needle guard comprises a first latch element arranged to interface with a corresponding second latch element secured within the housing;

Wherein the auto-injector further comprises an activation element initially in a first position in which the activation element is positioned to block the second latch element and thereby block abutment between the first latch element and the second latch element; and

Wherein when the needle guard is moved from the extended position to the retracted position, abutment between the needle guard and the activation element causes the activation element to move from the first position to a second position in which the second latch element is exposed to the first latch element such that subsequent movement of the needle guard from the extended position to the retracted position is prevented by abutment between the first latch element and the second latch element.