Drug delivery device

Abstract

A drug delivery device comprising: a housing, the housing including a drug delivery outlet at a proximal end of the housing; a cap releasably couplable to the housing, the cap being configured to seal the drug delivery outlet when coupled to the housing; and at least one locking mechanism comprising: a first abutment surface and a first blocking surface each disposed on the cap; and a second abutment surface and a second blocking surface each disposed on the housing; wherein the first and second abutment surfaces cooperate with one another to releasably couple the cap and housing together; and wherein the first and second blocking surfaces cooperate with one another to prevent re-coupling of the cap and housing following release of the coupling between the cap and the housing.

Description

[0001] DRUG DELIVERY DEVICE

[0002] BACKGROUND

[0003] Drug delivery devices, such as autoinjectors, injector pens and patch pumps, can be used to automate the delivery of injected drugs.

[0004] Drug delivery devices are available in a variety of sizes and designs, and at least part of each device is generally disposed of once one or more doses of the drug have been delivered. In many cases, these devices are intended to be single use, meaning that they should only be used to deliver a single dose before having to be reloaded or disposed of.

[0005] The drug delivery device should remain sterile and sealed until just before use, to prevent contamination and ensure that the drug or delivery system is not prematurely released. However, in many cases it can be difficult to distinguish between a used and unused device, as it may be possible to open / deploy the device (thereby breaking any sterile seal) and then close / stow it again into an apparently unused configuration. In addition, users often do not realise the importance of maintaining a sterile seal. As a result, inquisitive users may remove the cap of the drug delivery device to inspect it (as they would a pen or other device), doing so well ahead of when they are ready to use it. For safe use a device should be used shortly after removing this sterile seal, as if left for longer bacteria and air contact can contaminate the drug.

[0006] Accordingly, there is a need for drug delivery devices which are more hygienic and intuitive to use.

[0007] SUMMARY OF THE INVENTION

[0008] According to a first aspect of the invention, there is provided a drug delivery device comprising: a housing, the housing including a drug delivery outlet at a proximal end of the housing; a cap releasably couplable to the housing, the cap being configured to seal the drug delivery outlet when coupled to the housing; and at least one locking mechanism comprising: a first abutment surface and a first blocking surface each disposed on the cap; and a second abutment surface and a second blocking surface each disposed on the housing; wherein the first and second abutment surfaces cooperate with one another to releasably couple the cap and housing together; and wherein the first and second blocking surfaces cooperate with one another to prevent re-coupling of the cap and housing following release of the coupling between the cap and the housing.

[0009] I The drug delivery outlet may be an opening at the end of a nozzle or syringe, in some examples. In other examples, the drug delivery outlet may be sized for actuation of a drug delivery mechanism such as an actuator or plunger, which itself comprises a syringe or nozzle at a proximal end.

[0010] The blocking surfaces may be located at the most proximal ends of the housing and cap, in some examples.

[0011] The cap and housing cannot be re-coupled following release in the sense that the cap cannot be returned to its original position on the housing and be retained in place. This enables a user to easily distinguish between a sealed, sterile device in which the cap is fully coupled to the housing, and a previously opened, damaged or otherwise non- sterile device on which the cap is no longer fully coupled to the housing. In addition, the non-replaceable cap counteracts the natural inclination of some users to try to replace the cap on the housing after use, as they would do for a pen. This could otherwise cause confusion, as a user may not be able to remember if they have previously used a particular device. Blocking the user from replacing the cap will show that the drug delivery device is now in the ready to use state and cannot return to the storage state, indicating to the user to either use the device or dispose of it safely in a biohazard bin.

[0012] In some examples, it may be possible to partially re-couple the cap and housing to cover the drug delivery outlet, but only in a non-sealed second configuration which is distinguished from the original coupled configuration by one or more indicators (which may be visual or tactile indicators, or otherwise). This may allow the cap to be used to cover the drug delivery outlet during disposal, which is safer and more hygienic.

[0013] In other examples, the cap cannot be re-coupled even partially to the housing following release. If the cap cannot be re-coupled the device, then the visual distinction between a used and unused device is more clear, reducing the risk that a used device is confused with an unused device. Also, if a user does attempt re-coupling there is a small risk of a needle sharps accident.

[0014] The cap assembly typically contains a Rigid Needle Shield (RNS) that seals the drug delivery outlet in the sense that it provides a sterile seal around the outlet until released. This provides a sterile bond, reducing the contamination risk and the ensuing potential for infection of the injection site after use. The cap also protects the drug delivery outlet (whether a syringe needle or other mechanism) and its contents from air, as exposure to air can cause oxidation of some drugs and lead to formation of crystals which then grow and clog the drug delivery outlet. Preferably, the at least one of the first abutment surface and first blocking surface or the second abutment surface and second blocking surface is located on an elastically deformable component configured to deform during the release of the cap from the housing and then return to its original geometry. That is, the elastically deformable component has an original geometry when the cap and housing are coupled together. During release, the elastically deformable component deforms from this original geometry, enabling the cap to seperate from the housing. Following release, the elastically deformable component returns to its original geometry. In its original geometry, the blocking surfaces engage together so as to prevent re-coupling of the cap and housing. In other words, the elastically deformable component is deformed in the correct manner to release the cap from the housing, but cannot be easily deformed in the manner required to re-couple the cap in its original position on the housing.

[0015] Preferably, the at least one of the first abutment surface and first blocking surface or the second abutment surface and second blocking surface is located on a barb formed at a proximal end of the elastically deformable component. The elastically deformable component mat provide a restoring force which opposes deformation from its original geometry. Positioning the barb at a proximal end of the deformable section means that the barb can be translated laterally by deforming the elastically deformable component, allowing the abutment surfaces to be separated or slide over one another to release the cap from the housing.

[0016] Preferably, the elastically deformable component is configured to bias the first and second abutment surfaces towards one another, thereby to releasably couple the cap and housing together. In other words, the abutment surfaces are pressed together, creating higher frictional forces and thereby ensuring that the cap is retained more securely on the housing before release.

[0017] Optionally, the barb and elastically deformable component are integrally formed. Such an elastically deformable component may be lower-cost to manufacture, as fewer assembly stages are required.

[0018] Optionally, the barb and the elastically deformable component are formed as separate components. This may allow the barb and elastically deformable component to be made of a different material or manufactured in a different way to other components.

[0019] Optionally, the abutment surfaces are angled such that the barb is displaced away from the housing as the cap is released from the housing. In other words, the barb is displaced laterally, that is, in a direction perpendicular to an axial direction defined by the housing. As an axial force is used to displace the cap away from the housing in an axial direction, the angled abutment surfaces convert part of the axial force into a lateral force which causes the barb to displace away from the housing. The abutment surfaces may each comprise one or more flat or curved angled surfaces, in in order to control the displacement of the barb as the cap is released.

[0020] Preferably, the cap comprises at least one slit extending in a lengthwise axial direction of the drug delivery device. The at least one slit may extend through the whole length or a substantial part of the length of the elastically deformable component. The slits have the effect of lowering the second moment of area of the elastically deformable component along the length of the slit, reducing the component's bending stiffness and allowing it to deform more easily. In addition, the sections of the elastically deformable component can be bent or deformed independently.

[0021] Optionally, the abutment surfaces slide relative to one another thereby to facilitate release of the cap from the housing.

[0022] Preferably, at least one of: the first abutment surface and first blocking surface are separated by a first lip; and the second abutment surface and the second blocking surface are separated by a second lip. This means that during release, as soon as the abutment surfaces have translated beyond each other, the contact point between the cap and housing moves onto a blocking surface. From this position, it is no longer possible to re-couple the cap and housing. This may reduce the risk of the cap and housing becoming stuck half-way position during release.

[0023] Optionally, there comprise a plurality of locking mechanisms. Using a plurality of locking mechanisms ensures that the cap is restrained against the housing from multiple directions. The plurality of locking mechanisms may comprise a plurality of identical locking mechanisms separated by slits.

[0024] Optionally, the plurality of locking mechanisms are spaced equidistantly around a perimeter of the cap. The perimeter may be a circumference of the cap if the device is cylindrical. Alternatively if the cap has a regularly polygonal shape (e.g. a cuboid), the locking mechanisms may be arranged to align with the faces or corners of the cap.

[0025] Optionally, the drug delivery device comprises an autoinjector with pre-filled syringe or cartridge.

[0026] Optionally the cap comprises a rigid syringe needle shield (RIMS). The drug delivery device may fail to function if the drug delivery outlet is exposed to air, as oxidation may cause crystals to form in the outlet or chemically react with the drug. The syringe needle shield provides an additional layer of protection and airtight seal around a needle positioned at the proximal end of the housing. In some cases, the shield confirms closely to the exterior profile of the needle, to prevent crystals from being able to grow on exterior of needle.

[0027] Optionally, the housing comprises an end component and / or shield. The syringe collar prevents the syringe needle from lateral forces which could otherwise snap or bend the thin needle. In addition, the syringe collar may prevent the end of the cap from bucking when it is pressed towards the housing. Brief description of the drawings

[0028] Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0029] Figure 1 is an isometric view of an exemplary drug delivery device, showing the cap decoupled from the housing;

[0030] Figure 2 is an isometric view of the cap of the exemplary delivery device;

[0031] Figure 3 is a cross-sectional side view of the cap and part of the housing of the exemplary drug delivery device, showing the cap decoupled from the housing ;

[0032] Figures 4a-4d are cross-sectional side views of the cap and part of the housing of the exemplary drug delivery device, showing different stages during the release of the cap from the housing and attempted recoupling of the cap onto housing;

[0033] DETAILED DESCRIPTION

[0034] Referring to Figures 1-3, a drug delivery device in the form of an autoinjector, including a housing 100 and a cap 200. In other examples, the drug delivery device could be another kind of device such as an injector pen.

[0035] The housing 100 defines a central axis A about which the housing is radially symmetric.

[0036] The housing 100 comprises a rigid outer wall 101 which encloses a syringe cartridge 105. The syringe cartridge contains a deployable drug-filled syringe 109, which is tipped by a needle at its proximal end. The housing 100 comprises a drug delivery outlet 102 at a proximal end, through which the deployable syringe 109 may be actuated. The housing may be formed as a single part, or alternatively the proximal end of the housing including the drug delivery outlet 102 could be formed as a separate part joined to the rigid outer wall.

[0037] The syringe cartridge 105 includes a deployable collar 103 which protects the needle from the sides. As the cap 100 is released, the deployable collar 103 may move forwards along the axial direction from its resting position within the housing 100, by means of an actuation mechanism (not visible).

[0038] The cap 200 comprises four locking mechanisms 201. The locking mechanisms 205 are arranged equidistantly around the central axis A of the housing and cap, separated from each other by slits 205. Each locking mechanism 201 comprises a barb 202. The barb has a blocking surface 204 at its proximal end, and an angled abutment surface

[0039] 206 facing inwards towards the central axis A.

[0040] While the illustrated cap 200 features four locking mechanisms 201, alternatives are envisaged in which there are more arms, e.g. five, six or less, three, two or even a single locking mechanism 201.

[0041] Each barb 202 is located at a proximal end of an elastically deformable component 207. Each elastically deformable component 207 has a thin cross-section along its length compared to the rest of the cap 200. Each elastically deformable component

[0042] 207 is also separated from neighbouring elastically deformable components by slits

[0043] 205 extending along its length, allowing the elastically deformable components 207 to flex and bend independently of each other. The slits 205 are aligned with the central axis A of the housing, in the sense that the long axis of each slit 205 is parallel to the central axis A. As a result of their thin cross-sections and the slits 205, the elastically deformable components each have a lower second moment of area than the rest of the cap 200 and thereby a lower bending stiffness. As a result, the elastically deformable components 207 act as springs which provide a restoring force when bent. In other examples, the elastically deformable components 207 could be located on the proximal end of the housing 100, rather than on the cap 200.

[0044] The cap abutment surface 206 is configured to engage with a corresponding abutment surface 106 on the housing. The cap blocking surface 204 is configured to engage with a corresponding blocking surface 104 on the housing. The cap blocking surface 204 forms a lip at the end of the cap abutment surface 206. The housing blocking surface 104 and cap blocking surface 204 may be considered the first and second blocking surfaces, respectively. The housing abutment surface 106 and cap abutment surface

[0045] 206 may be considered the first and second abutment surfaces, respectively.

[0046] The barb 202 and elastically deformable component 207 are integrally formed as part of the cap 200. In other examples, the cap 200 itself may constitute an elastically deformable component, in that its overall geometry may deform during the release of the cap 200 from the housing and then elastically return to its original geometry. In other examples, the elastically deformable components 207 and / or barbs 202 are formed as separate components to the base of the cap 200, such that the cap 200 is a rigid body and only the geometry of the elastically deformable components 207 and barbs 202 is temporarily deformed during release.

[0047] In the example shown, the cap 200 further includes a syringe needle shield 210, which is configured to fit around the syringe and protect it from damage and corrosion. The syringe needle shield 210 may include a retaining flange 211 configured to engage with a corresponding retaining flange 111 on the syringe 109.

[0048] The housing 100 and / or cap 200 may be made from metal, plastic (HDPE, PC, ABS or a combination thereof) or other suitable material, and may be formed using injection moulding or other suitable manufacturing technique.

[0049] Figures 4a-4c illustrate the stages of release of a cap 200 from a housing 100.

[0050] Starting with Figure 4a, the cap 200 is securely coupled to a housing 100. The cap 200 and housing are engaged along their respective abutment surfaces 106, 206. The angled abutment surfaces 106, 206 press together when the cap 200 is translated along the central axis A away from the housing 100, generating frictional forces which couple the cap 200 to the housing 100. In some embodiments, the elastically deformable components 207 of the cap 200 are biased to generate a lateral force pressing the abutment surfaces 106, 206 together and further increasing the frictional forces.

[0051] The abutment surfaces 106, 206 are angled such that each barb 202 increases in thickness towards the direction of the housing 100, and the corresponding section of the housing 100 increases in thickness towards the direction of the cap 200. As a result, the cap 200 cannot be removed from the housing without deforming one or more elastically deformable components 207.

[0052] In Figure 4b, the cap 200 is in the process of being released from the housing 100. To release the cap 200, an axial force Fl is applied along the central axis A pulling the cap 200 away from the housing 100. The angled abutment surface 106 on the housing 1000 converts a portion of the axial force Fl into a lateral force, which directs the barbs 202 to move laterally outwards away from the housing 100 on the proximal end of the elastically deformable components 207. By displacing the barbs 202 laterally outwards, the blocking surfaces 206 on the cap 200 are able to pass around the corresponding blocking surfaces on the housing 106.

[0053] The cap blocking surface 204 is separated from the cap abutment surface 206 by a lip. Thus as soon as the cap abutment surface 204 is clear of the housing abutment surface 104, the restoring force from the elastically deformable component 207 causes the barb 202 to begin displacing laterally inwards towards the central axis A back to its original geometry. Once the barb is in its original geometry, the cap blocking surface 204 overlaps in space with the housing blocking surface 104. In Figure 4c, the cap 200 is fully released and decoupled from the housing 100. The cap 200 has returned to its original undeformed shape.

[0054] In Figure 4d, an attempt is made to re-couple the cap 200 to the housing 100, by applying a force F2 to press the cap 200 into the housing along the central axis A. When the cap 200 is pressed against the proximal end of the housing 100, the housing blocking surface 204 overlaps with and engages with the cap blocking surface 104.

[0055] The blocking surfaces 204, 104 are angled to face inwards towards the central axis A. As a result, increasing the force F2 will simply cause the blocking surface 204 on the cap to slide laterally inwards towards the central axis A along the blocking surface 104 on the housing 200. Since the barbs 202 must deform laterally outwards for the cap 200 to be re-coupled, the cap 200 will not re-attach even if high pressing forces are applied. As more force is applied, the resultant force through the blocking face 204 presses onto the needle shield 103, preventing the barb 202 and elastically deformable component 207 from buckling inwards.

Claims

CLAIMS1. A drug delivery device comprising: a housing, the housing including a drug delivery outlet at a proximal end of the housing; a cap releasably couplable to the housing, the cap being configured to seal the drug delivery outlet when coupled to the housing; and at least one locking mechanism comprising: a first abutment surface and a first blocking surface each disposed on the cap; and a second abutment surface and a second blocking surface each disposed on the housing; wherein the first and second abutment surfaces cooperate with one another to releasably couple the cap and housing together; and wherein the first and second blocking surfaces cooperate with one another to prevent re-coupling of the cap and housing following release of the coupling between the cap and the housing.

2. The drug delivery device of claim 1, wherein the at least one of the first abutment surface and first blocking surface or the second abutment surface and second blocking surface is located on an elastically deformable component configured to deform during the release of the cap from the housing and then return to its original geometry.

3. The drug delivery device of claim 2, wherein the at least one of the first abutment surface and first blocking surface or the second abutment surface and second blocking surface is located on a barb formed at a proximal end of the elastically deformable component.

4. The drug delivery device of claim 3, wherein the elastically deformable component is configured to bias the first and second abutment surfaces towards one another, thereby to releasably couple the cap and housing together.

5. The drug delivery device of claim 3 or 4, wherein the barb and elastically deformable component are integrally formed.

6. The drug delivery device of any of claim 3 or 4, wherein the barb and the elastically deformable component are formed as separate components.

7. The drug delivery device of any of claims 3 to 6, wherein the abutment surfaces are angled such that the barb is displaced away from the housing as the cap is released from the housing.

8. The drug delivery device of any preceding claim, wherein the cap comprises at least one slit extending in a lengthwise axial direction of the drug delivery device.

9. The drug delivery device of any preceding claim, wherein the abutment surfaces slide relative to one another thereby to facilitate release of the cap from the housing.

10. The drug delivery device of any preceding claim, wherein at least one of: the first abutment surface and first blocking surface are separated by a first lip; and the second abutment surface and the second blocking surface are separated by a second lip.

11. The drug delivery device of any preceding claim, comprising a plurality of locking mechanisms.

12. The drug delivery device of claim 11, wherein the plurality of locking mechanisms are spaced equidistantly around a perimeter of the cap.

13. The drug delivery device of any preceding claim, where the drug delivery device comprises an autoinjector with pre-filled syringe or cartridge.

14. The drug delivery device of any preceding claim, wherein the cap comprises a syringe needle shield.

15. The drug delivery device of any preceding claim, wherein the housing comprises an end component and / or shield.

Images