Automated Injection System

Abstract

The present invention provides an automatic injection system for transdermal or intradermal delivery of drugs and the like which provides a robust yet greatly simplified means of operation, the system comprising an elongate housing forming a handle, at one end of which is located an array of five microneedles, the injection system further comprising an internal reservoir of drug to be injected through the microneedles, and an actuator assembly contained within the housing, the actuator assembly being arranged to enable the injection system to be operated by a simple one-handed gripping and depressing action by a user to not only insert the microneedles into the skin but also to automatically inject the drug.

Description

[Technical Field]

[0001] The present invention relates to an automatic injection system, and in particular to an injection system for transdermal or intradermal delivery of drugs and the like, which provides a robust yet significantly simplified means of operation, thereby enabling reliable self-injection. [Background technology]

[0002] Due in part to changing social behaviors and an aging population, chronic diseases and conditions are becoming more prevalent. Therapeutic treatments using biologics (including antibodies, therapeutic proteins, peptides, and cell therapies) offer clear advantages in efficacy and selectivity, demonstrating their application in the treatment of cancer and cancer-related diseases, rare diseases, neurological disorders, and autoimmune diseases. However, the specific physiochemical properties of biologics (e.g., high viscosity) mean that they are difficult to deliver as active agents into the body, potentially requiring either intravenous (IV) or subcutaneous administration. The emergence of patient-centric “auto-injector” designs and devices has enabled users of a wide range of chronic disease states to self-inject medications subcutaneously on a daily basis at home, advantageously eliminating the need for visits to a hospital or infusion center.

[0003] Yet existing subcutaneous autoinjectors have several limitations. In these prior art designs, drugs are typically administered via a single needle inserted vertically through the skin. A common approach to needle insertion involves, for example, using potential energy stored in a spring to propel the needle through the skin with considerable velocity and force. In addition to potentially causing pain and discomfort to the patient, this action can result in needle breakage. Depending on factors such as the volume and viscosity of the drug, a "hold time" of several seconds to several minutes may be required for the autoinjection to be administered (and typically requires a second stored potential energy source). Elderly patients and those with dexterity issues and / or tremors may have difficulty maintaining a steady hand during this injection phase. Highly viscous biologics are known to be associated with long injections and "hold times." However, one strategy to reduce injection time, and therefore "hold times," by reformulating the drug to a lower viscosity while retaining the payload requires a larger injection volume, which not only places additional demands on device engineering but also impacts the patient experience.

[0004] Skin as a delivery site (intradermal delivery) for both biologics and vaccines offers unparalleled efficiency (ie, dose sparing) and efficacy (ie, dose response).

[0005] However, this form of delivery using the so-called Mantoux Technique can be difficult or time-consuming to perform for a variety of reasons, including the experience of the administerer and the precision required to perform the procedure, the location and / or condition of the delivery site, the finite thickness of the skin, and the required depth of delivery. As a result, this injection method is generally not suitable for self-injection. This can increase the difficulty of performing the traditional task of intradermal injection, especially for individuals with reduced dexterity, impaired vision, or other physical disabilities. Furthermore, delivery of highly viscous drugs using a single needle poses significant challenges.

[0006] Therefore, there is a need for an intradermal injection system that can be used for self-injection, is simple to use, reliable, and reproducible. Furthermore, there is a need for an injection system that can deliver vaccines and viscous biologics quickly, with low injection pressures, and that can be easily handled by all patient types.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to address the above-mentioned problems. Summary of the Invention

[0008] According to the present invention, there is provided an automatic injection system comprising an elongate housing defining a handle, an actuator assembly disposed within the housing and longitudinally displaceable relative to the housing, an injection head attached to the actuator assembly and projecting from the lower open end of the housing, the injection head including a pair of jaws displaceable relative to one another transverse to a longitudinal axis of the housing in response to relative longitudinal displacement between the housing and the actuator assembly, each jaw having one or more hollow microneedles projecting therefrom, a reservoir of liquid contained within the housing in fluid communication with one or more of the hollow microneedles, and a dispenser operable to pressurize fluid in the reservoir in response to relative longitudinal displacement between the housing and the actuator assembly to dispense the liquid from the one or more hollow microneedles.

[0009] Preferably, the reservoir is defined by a syringe including a cylinder closed at one end by a piston displaceable within the cylinder by a dispenser to pressurize the fluid.

[0010] Preferably, the dispenser includes a spring-loaded plunger in operative association with the piston.

[0011] Preferably, the plunger includes an abutment and the actuator assembly includes a latch member to which the abutment is releasably retained.

[0012] Preferably, the actuator assembly is operable to effect sequential displacement of the abutment and the latch member into engagement and disengagement before or after completion of relative lateral displacement of the pair of jaws.

[0013] Preferably, the actuator assembly includes a biasing element arranged to bias disengagement of the abutment and latch member following relative longitudinal displacement between the housing and the actuator assembly.

[0014] Preferably, the biasing element includes a guide member fixed to the housing and displaceable relative to the latch member in response to relative longitudinal displacement between the housing and the actuator assembly to bias disengagement of the abutment and the latch member.

[0015] Preferably, one of the jaws and the housing includes a cam and the other of the jaws and the housing includes a corresponding follower, the cam having a profile arranged to effect relative lateral displacement of the pair of jaws in response to relative longitudinal displacement between the housing and the actuator assembly.

[0016] Preferably, each jaw includes a cam and the housing includes a corresponding pair of followers.

[0017] Preferably, the actuator is arranged to undergo rotational displacement in response to linear displacement relative to the housing.

[0018] Preferably, the injection head is operable to convert rotational displacement of the actuator assembly into relative lateral displacement of the pair of jaws.

[0019] Preferably, the or each cam is profiled to allow two-stage displacement of the jaws, with a first stage configured to effect relative transverse displacement of the jaws in response to relative longitudinal displacement between the housing and the actuator assembly, and a second stage allowing relative movement between the jaws without relative longitudinal displacement between the housing and the actuator assembly.

[0020] Preferably, the or each cam is contoured to define a third phase between the first and second phases that allows relative longitudinal displacement between the housing and the actuator assembly in the absence of relative lateral displacement of the jaws.

[0021] Preferably, the injection head includes at least one release member manually operable to reverse the relative lateral displacement between the pair of jaws.

[0022] Preferably, the housing includes an aperture in the side wall through which the release member is accessible following relative longitudinal displacement between the housing and the actuator assembly.

[0023] Preferably, the injection system includes a longitudinally displaceable sleeve on the housing, the sleeve being displaceable into engagement with at least one release member to reverse the relative lateral displacement between the pair of jaws.

[0024] Preferably, the injection system includes a locking element operable to prevent reversal of the relative longitudinal displacement between the housing and the actuator assembly.

[0025] Preferably, the actuator assembly comprises an elongate frame around which the housing is supported, within which the reservoir is housed, and the injection head is attached to an end of the frame.

[0026] Preferably, the hollow microneedles on each jaw are angled towards the hollow microneedles on the other jaw.

[0027] Preferably, the injection system includes a releasable and securable cap around the lower end of the housing to enclose the injection head.

[0028] Preferably, the automatic injection system includes a spring positioned to bias the housing longitudinally of the actuator assembly.

[0029] Preferably, the spring comprises a leaf spring disposed between the actuator assembly and the closed end of the housing.

[0030] The present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1a] 1 shows a front view of an embodiment of an automatic injection system according to the present invention in an undeployed state. [Figure 1b] 2 shows the automatic injection system of FIG. 1 in a deployed state. [Figure 1c] 3 shows the automatic injection system of FIGS. 1 and 2 in a released state. [Figure 2a] FIG. 1b shows a cross-sectional view of the injection system shown in FIG. 1a. [Figure 2b] FIG. 1c shows a cross-sectional view of the injection system shown in FIG. 1b. [Figure 2c] 1b shows the injection system shown in FIG. 1b after actuation of the syringe. [Figure 2d] FIG. 1c shows a cross-sectional view of the injection system shown in FIG. [Figure 3] 1a, b and c show enlarged views of the injection head of the automatic injection system shown in FIGS. 1a, 1b and 1c. [Figure 4] 4a, b and c show, in partially exploded and assembled views, an actuation assembly forming part of the automatic injection system shown in FIGS. 1-3. [Figure 5]FIG. 5 shows a perspective view of the automatic injection system of FIGS. 1-4 in an undeployed state. [Figure 6] FIG. 6 shows an exploded perspective view of the automatic injection system of FIGS. [Figure 7] 7a, b and c show various exploded perspective views of an injection head and syringe combination forming part of the automatic injection system of FIGS. 1 to 6. [Figure 8] 7a, b and c show various front views of the injection head and syringe combination shown in FIGS. 7a, 7b and 7c. [Figure 9] 1 shows a perspective view of an alternative embodiment of an automatic injection system according to the present invention in an undeployed state. [Figure 10] 10 shows a perspective view of the alternative embodiment of FIG. 9 in an unfolded state. [Figure 11a] FIG. 10 shows a cross-sectional view of the automatic injection system shown in FIG. 9. [Figure 11b] 11 shows a cross-sectional view of the automatic injection system shown in FIG. 10. [Figure 11c] 11 shows the automatic injection system of FIGS. 9 and 10 in a released state. [Figure 12a] 10 shows a front view of a further alternative embodiment of an automatic injection system according to the present invention and in an undeployed state. [Figure 12b] 12b shows a cross-sectional view of the automatic injection system shown in FIG. 12a. [Figure 12c] 12b shows the automatic injection system of FIG. 12b in a deployed state. [Figure 13a] 12a and 12b show cross-sectional perspective views of the automatic injection system shown in FIG. 12a and FIG. 12b. [Figure 13b] FIG. 13a shows half of the housing of the automatic injection system in an undeployed state. [Figure 13c] 13b in an unfolded state. [Figure 14] 10 shows a perspective view of a two-part automatic injection system according to a further alternative embodiment of the present invention and in a partially separated state. [Figure 15] FIG. 15 shows a front view of the injection system of FIG. 14. [Figure 16]16 shows an assembly diagram of the injection system shown in FIGS. 14 and 15. FIG. [Figure 17] 10 shows a front view of a further embodiment of an automatic injection system according to the present invention in an undeployed state. [Figure 18] 18 shows a side view of the automatic injection system of FIG. 17. [Figure 19] 19 shows the injection system shown in FIGS. 17 and 18 after engagement of a pair of jaws and actuation of the syringe. [Figure 20] 17-19 after retraction of the pair of jaws caused by telescoping of the housing of the injection system. [Figure 21] 10 shows a perspective view of the bottom of a further alternative embodiment of an automatic injection system according to the present invention, with a pair of jaws in a non-deployed state. [Figure 22] 22 shows a plan view of the lower part shown in FIG. 21. [Figure 23] 23 shows a plan view from below of the injection system of FIGS. 21 and 22, with the pair of jaws in an undeployed state. FIG. [Figure 24] 214 illustrates the automatic injection system shown in FIG. 213, but with the pair of jaws in an deployed position. DETAILED DESCRIPTION OF THE INVENTION

[0032] Referring now to Figures 1 to 8 of the accompanying drawings, there is shown an automatic injection system, generally designated as 10, operable to provide a simple and consistent means for injecting fluid medications (not shown) and the like into tissue, particularly for intradermal delivery, and most preferably for enabling self-injection by allowing such injections to be performed using one hand.

[0033] The injection system 10 includes an elongated, substantially cylindrical housing 12, the length and diameter of which are appropriately sized to fit comfortably within a user's hand by defining a pistol-grip handle for holding and manipulating the injection system 10 during use. The housing 12 may be formed from any suitable material or combination of materials, for example, by injection molding of plastic. The housing 12 includes a closed upper end 14 and an open lower end 16 from which extends an injection head 18. The injection head 18 includes a pair of opposing jaws 20, each having a number of hollow microneedles 22 projecting from its underside, sloping toward the opposing jaw 20. The injection system 10 is operable to automatically insert the array of microneedles 22 into skin or other tissue and then inject a liquid medicament when the housing 12 is grasped by a user and the injection head 18 is pressed against the skin, as described in detail hereinafter, thereby enabling a simple, one-handed procedure.

[0034] 2 and 6, the interior of injection system 10 is shown, comprising an actuator assembly 24 captured within housing 12, the actuator assembly adapted to undergo longitudinal displacement relative to housing 12 to provide various automated functions, as described hereinafter. Housing 12 is preferably fabricated as a clamshell structure including a pair of halves snap-fit ​​or otherwise secured together to capture actuator assembly 24 therebetween, as shown, for example, in FIG. 6. A pair of parallel guide rails 25 may be integrally formed on the interior of housing 12 to guide actuator assembly 24 during relative longitudinal displacement.

[0035] The actuator assembly 24 includes an elongated frame 26, shown in isolation in FIGS. 4a-4c, within which is mounted a syringe 28 containing a liquid medication for injection. The frame 26 is preferably formed from a polymer, although any other suitable material may be used. The injection head 18 is attached to the lower end of the frame 26 so as to protrude from the lower end 16 of the housing 12 and is in fluid communication with the syringe 28. As a result, with reference to both FIGS. 1 and 2, the housing 12 can thus be longitudinally displaced relative to the actuator assembly 24 and injection head 18 from an undeployed state or configuration shown in FIGS. 1a and 2a, in which the microneedles 22 contact the skin, to a deployed state or configuration shown in FIGS. 1b and 2b, in which relative longitudinal displacement between the housing 12 and the actuator assembly 24 inserts the microneedles 22 into the skin. This is achieved by translating the relative longitudinal displacement between the housing 12 and the actuator assembly 24 into a relative displacement between the pair of jaws 20 in a direction transverse to the direction of the longitudinal displacement, as will be described in detail hereinafter. For reference, the injection system 10 is preferably held substantially perpendicular to the skin during use, with the longitudinal axis of the housing 12 defining the longitudinal displacement, such that the jaws 20 undergo a transverse displacement relative to this direction, and thus a displacement generally parallel to the skin surface. This transverse or lateral displacement acts to insert the angled microneedles 22 into the skin, with opposing sets of microneedles 22 acting in an overlapping manner to grip the intervening skin and thereby hold or anchor the microneedles 22 in place to ensure stability during use and thus accurate and consistent injection of the liquid medicament. This anchoring action has been described in detail in prior International Application WO 2018 / 069543 and therefore need not be further described with respect to this particular aspect of the invention.

[0036] Once the microneedle 22 is either partially or fully anchored in the skin or other tissue, the final longitudinal displacement of the housing 12 towards the skin and relative to the actuator assembly 24 results in the actuation of the syringe 28 to inject the liquid medication through the microneedle 22 and into the surrounding tissue, as described in detail hereinafter. This stage is shown in Figure 2c, after which the microneedle 22 can be manually operated to release it from the skin to allow the injection system 10 to be disengaged and retracted, as shown in Figures 1c and 2d. This action will be described in detail again hereinafter.

[0037] Thus, a primary function of the automatic injection system 10 is to enable a single, simple action: pressing the injection head 18 against the skin using the housing 12 as a handle, aligning it to insert the microneedle 22 into the skin, and then injecting fluid from the syringe 28 through the implantable microneedle 22. To accomplish the first phase of the injection action, the pair of jaws 20 are positioned to undergo short-term or lateral displacement relative to one another in response to longitudinal displacement of the housing 12 relative to the actuator assembly 24 under downward pressure applied by use via the housing 12. The pair of jaws 20 are interlocked with one another, and FIG. 7a shows the jaws 20 completely separated from one another prior to assembly with the frame 26, FIG. 7b shows the jaws 20 joined together for assembly, and FIG. 7c shows the jaws 20 interlocked, ready to receive and be secured to the frame 26, and positioned within the housing 12 during operation. Figure 8a shows a front view of the arrangement seen in Figure 7c, Figure 8b shows a front view with the frame 26 advanced downwardly between the jaws 20, and Figure 8c shows the jaws 20 displaced relative to one another so as to be coupled to the frame 26 as described hereinafter.

[0038] When interlocked, the jaws 20 can undergo limited translational displacement relative to one another to slide the microneedles 22 on each jaw 20 toward one another to engage and embed the microneedles 22 in the skin. Each jaw 20 includes an inner wall 30, which, because of their face-to-face contact with one another, preferably has a smooth surface finish to allow the jaws 20 to slide relative to one another with limited friction. The jaws 20 further include upstanding tabs 36 defining a housing or space therebetween within which the lower end of the frame 26 and a fluid manifold 38 are located. The fluid manifold 38 is captured between the upper surfaces 40 of the pair of jaws 20 and a clamp rail 42 to secure the injection head 18 to the frame 26 of the actuator assembly 24. As can be seen in FIG. 5 , the upstanding tabs 36 provide a visual shield to conceal the internal elements of the device from the user. Tapered contact surfaces on the fluid manifold 38 and the clamp rail 42 ensure a fluid-tight seal between the fluid manifold 38 and the upper surface 40 of the jaw 20. One or more fluid conduits 32 extend from each top surface 40 through the jaws 20 to the respective microneedles 22. In this manner, a flow path is established from the syringe 28 through the fluid manifold 38 and jaws 20 to the microneedles 22. An example of this interface between a pair of jaws 20, fluid manifold 38 and syringe 26 is described and shown in detail in applicant's international application PCT / EP2022 / 062653, so further explanation of the construction and operation of this aspect of the invention is not necessary.

[0039] Each jaw 20 further includes a cam 44 in the form of a channel formed in an outer surface 46 of the jaw 20, offset from the inner wall 30 and positioned so as to be positioned above and along the lower portion of the opposing jaw 20 when the pair of jaws 20 are interlocked, as shown in FIG. 7c. The cam 44 is contoured to define a first phase 48 that extends simultaneously downward and laterally outward, and a second phase 50 that extends laterally only along the underside of the outer surface 46 of the jaw 20 from the open lower end of the channel. The housing 12 is provided with a corresponding pair of followers 52 (see FIGS. 3 and 6) in the form of a pair of opposing pins 52 that project from the inner surface of the housing 12 on opposite sides thereof to be captured within the respective cam 44. The follower 52 is positioned on the housing 12 such that, while the injection system 10 is in an undeployed state, the follower 52 seats at the upper end of the channel defining the cam 44, as shown, for example, in Figure 3a, which corresponds to the state shown in Figures 1a and 2a. It will therefore be appreciated that relative longitudinal displacement between the housing 12 and the injection head 18 drives the follower 52 to lower the cam 44 from the position shown in Figures 2a and 3a to the position shown in Figures 2b and 3b as it presses the housing 12 towards the skin. Thus, due to the orientation of the first phase 48 of the cam 44, the transverse displacement of each jaw 20 towards the other jaw 20 displaces the microneedles 22 across the skin, and pressure applied to the housing 12 by the user forces the microneedles 22 into the skin. This action causes the angled microneedles 22 to penetrate the skin, and the overlapping array of microneedles 22 anchors the injection head 18 to the skin to allow for uninterrupted injection of liquid medication from the syringe 28.

[0040] The second phase 50 of the cam 44 allows the jaws 20 to reverse or be displaced away from each other to withdraw the microneedles 22 from the skin after injection of the fluid, as will be provided in greater detail hereinafter. The second phase 50 of the action of the cam 44 and follower 52 occurs when the follower 52 is displaced out of the lower open end of the channel defining the cam 44, thereby allowing the follower 52 to be displaced laterally relative to the jaw 20 so that it moves along the underside or lower edge of the outer surface 46. The second phase 50 may include a shallow detent within the lower edge of the outer surface 46 to define a stop or limiter for the lateral movement of the jaw 20. It should be understood that the positions of the cam 44 and follower 52 may be reversed, with the cam formed within the wall of the housing 12 and the follower provided on the outer surface of the jaw 20. It will also be appreciated that the second phase 50 of the cam 44 may not be defined directly beneath the outer surface 46, but may instead be formed as a transverse extension of a channel within the outer surface 46. Accordingly, the term "cam" is intended to refer to one or more elements defining a fixed path along which another element, such as the follower 52, is restricted in order to impart a desired sequence of motion to a working component (in this case, the jaws 20). In this embodiment, the fixed path includes two distinct phases: a first phase 50 moving along and within the channel within the cam 44, and a second phase of free transverse motion along the underside of the outer surface 46 once the follower 52 exits the channel. However, it will be appreciated that these two phases of motion may be achieved by other mechanical components acting to impart the required path of motion to the pair of jaws 20. It will also be appreciated that the second phase of displacement may simply be a reversal of the first phase, as described hereinafter with respect to an alternative embodiment.

[0041] Turning to the operation of the syringe 28, the frame 26 of the actuator assembly 24 includes a pair of elongated side members 54 that, together with a cross member 56 and the lower end of the frame 26, define a housing in which the barrel 58 of the syringe 28 is positioned and retained. A dispenser or plunger 60 of the syringe 28 extends through the cross member 56 and terminates in an abutment or head 62 that is located toward the upper end 14 of the housing 12 when the syringe is filled and primed for use. The elongated side members 54 extend longitudinally beyond the cross member 56, with free ends 64 of the side members 54 connected by a loop of flexible material forming a leaf spring 66, which effectively defines cantilevers that can resiliently deform laterally or laterally away from one another, as described hereinafter. The leaf spring 66 acts against the closed upper end 14 of the housing 12 to hold the actuator assembly 24 and housing 12 in their undeployed relative positions. The leaf spring 66 has sufficient bias to hold the housing 12 in the longitudinal position described above in the absence of external pressure, but is weak enough to be easily overcome by a user grasping the housing 12 and pressing the injection head 18 against the skin, causing relative longitudinal displacement of the housing 12 and actuator assembly 24 against the bias of the leaf spring 66. The leaf spring 66 may be formed from any suitable material, and may, for example, be molded integrally with the side member 54 from a polymer or the like.

[0042] The actuator assembly 24 further includes a compression spring 68 that is seated around the plunger 60 and is captured and compressed between the top surface of the piston (not shown) of the syringe 28 and the cross member 56, thereby applying a biasing force to the piston and urging the plunger 60 into the barrel 58 to expel the liquid medicament from the barrel 58. However, the free ends 64 of the side members 54 engage directly below the head 62 and therefore function as latching members that prevent the compression spring 68 from depressing the plunger 60. The actuator assembly 24 includes guide members in the form of a pair of ramps 70 that project from the interior wall of the housing 12 adjacent the top end 14 in response to longitudinal displacement of the housing 12 relative to the actuator assembly 24, thereby engaging and displacing the free ends 64 of the side members 54 transversely into disengagement with the head 62. In particular, the thin end of each ramp 70 defines the proximal end of the ramp 70 relative to the direction of displacement of the housing 12, and thus the thin end first contacts the end of the side member 54 adjacent the free end 64, with further longitudinal displacement of the housing 12 driving the ramp 70 relative to the side member 54, resulting in its transverse displacement. The side member 54 is resilient and deformable to allow this deflection of the free end 64. The side member 54 may be formed, for example, from any suitable polymer. The ramp 70 is positioned and dimensioned to displace and remove the free end 64 from the head 62 only after the pair of jaws 20 have undergone their full relative displacement, such that the microneedles 22 are fully embedded and stabilized in the skin. It will be understood that the ramp 70 is merely one exemplary form of mechanical arrangement operable to convert longitudinal displacement of the housing 12 into lateral displacement of the side member 54 or otherwise latch the head 62, and that any other functional alternative may be used.

[0043] As the free end 64 deforms laterally or sideways away from the head 62, the bias of the spring 68 is released, driving a piston (not shown) down the barrel 58 of the syringe 28 to force the liquid medicament through the microneedle 22 and into tissue. Figure 2c shows the injection system 10 at this stage, with the free end 64 deformed outward and the plunger 60 depressed, so that the spring 68 is no longer compressed. The housing 12 preferably includes a window 72 adjacent the barrel 58 of the syringe 28 to allow the user to visually confirm that the liquid medicament has been dispensed and thus injected into the skin or other tissue.

[0044] At this point, the injection system 10 has completed the injection of the drug and needs to be removed; however, the microneedle 22, still embedded in the skin, needs to be retracted before the injection system 10 can be detached. To retract the microneedle 22, the relative lateral displacement of the jaws 20 needs to be reversed. To facilitate this action, the housing 12 is provided with a pair of lateral openings 74 proximal to the lower end 14, each positioned to receive a release member in the form of a button 76 protruding from the upstanding tab 36 of each jaw 20. The openings 74 are longitudinally elongated to accommodate the buttons 76 during relative longitudinal displacement between the housing 12 and the injection head 18. Furthermore, as the jaws 20 are displaced laterally together, the buttons 76 are displaced laterally outward so as to protrude further from the openings 76. When the housing 12 is fully depressed against the skin and the injection head 18 is substantially displaced into the housing 12 through the open lower end 16, the housing 12 may taper inwardly in the region of the opening 76 to define a narrow waist at the upper end of the opening 76 to further expose the button 76.

[0045] It will thus be appreciated that once the medication has been injected, the jaws 20 can be displaced back to their undeployed state by the user firmly depressing the pair of buttons 76 inward on the housing 12, forcing the jaws 20 back to their undeployed position. This action also allows the microneedle 12 to be withdrawn from the skin and disengage the injection system 10. Figures 1c, 2d, and 3c show the injection system 10 with the buttons 76 depressed back into the housing 12, causing the jaws 20 to return to their undeployed state. The second phase 50 of each cam 44 facilitates this lateral displacement of the jaws 20 without requiring any relative longitudinal displacement between the housing 12 and the injection head 18.

[0046] Because the injection system 10 is preferably a disposable product that cannot be reused, inadvertently or otherwise, it is desirable that the housing 12 cannot be displaced back to its undeployed state. Accordingly, the actuator assembly 24 includes a locking element 78 operable to prevent reversal of the relative longitudinal displacement between the housing 12 and the actuator assembly 24. The locking element 78 includes a resiliently deformable detent 80 integrally formed with and projecting laterally from one of the side members 54, and a corresponding tab 82 provided on the interior wall of the housing 12. The tab 82 is positioned to contact, deflect, and pass the detent 80 during relative longitudinal displacement between the housing 12 and the actuator assembly 24. However, the detent 80 and the tab 82 are contoured to prevent reverse passage of the detent 80, in the illustrated embodiment, by defining a ratchet-type arrangement. In this manner, the housing 12 is prevented from returning to its undeployed state after the syringe 28 has been actuated and the medication dispensed. This is primarily for safety reasons.

[0047] 9-11, an automatic injection system according to an alternative embodiment of the present invention is shown and generally designated 110. In this alternative embodiment, like components are given like reference numerals and perform like functions unless otherwise specified. The injection system 110 comprises a hollow housing 112 defining a handle, an injection head 118 located at a lower end 116 of the housing 112, and an actuator assembly 124 located within the housing 112. A syringe 128 of liquid medication is secured within the actuator assembly 124 in a manner identical to that previously described herein and is in fluid communication with one or more microneedles 122 projecting from a pair of jaws 120 of the injection head 118.

[0048] To achieve relative transverse displacement of the jaws 120 in response to relative longitudinal displacement of the housing 112 with respect to the actuator assembly 124, each jaw 120 includes a cam 144 formed in its top wall 146, in this embodiment, located on the same side of the jaw 120 on which the respective microneedle 122 is located. The cam 144 includes only a first phase 148 terminating in a well 148a oriented to hold the jaws 120 in a fixed relative position to allow fluid to be injected through the microneedle 122. Unlike the first embodiment described above, the jaws 120 do not include any externally accessible release member to allow reversal of the relative transverse displacement of the jaws 120 to withdraw the microneedle 122 from the skin. Instead, the actuator assembly 124 includes a locking element in the form of a resilient deformable detent 180 integrally formed with and projecting laterally therefrom, and a corresponding socket 182 provided in the wall of the housing 112. Tab 180 is positioned to deflect inward by contacting a recess in housing 112 around socket 182 before reaching socket 182 and deflecting outward into the socket at the end of relative longitudinal displacement between housing 112 and actuator assembly 124. When captured within socket 182, detent 180 prevents reversal of relative motion between housing 112 and actuator assembly 124. In this manner, housing 112 is prevented from returning to its undeployed state after syringe 128 is actuated and medication is dispensed. However, detent 180 is externally accessible, as clearly seen in FIG. 10 , allowing a user to depress detent 180 and disengage it from socket 182.At this point, the housing 112 is free to displace longitudinally relative to the actuator assembly 124, so that when the user releases the downward pressure on the skin, the leaf spring 166, when compressed between the closed top end 114 of the housing 112 and the actuator assembly 124, acts to reverse the longitudinal displacement between the housing 112 and the actuator assembly 124, helping to push the housing 112 upward and away from the skin. This displacement therefore reverses the lateral displacement of the pair of jaws 120, allowing the microneedle 122 to be withdrawn from the skin and disengage the injection system 110 from the skin. Each jaw 120 is provided with a lateral extending guide rail 184 and a corresponding channel 186, such that the guide rail 184 of one jaw 120 is captured within the channel 186 of the other jaw 120 when interlocked. The guide rails 184 and channels 186 are dimensioned to facilitate relative lateral displacement of the jaws 120 while providing interconnectivity and stability to the jaws 120 during operation.

[0049] In a modification of the injection system 110, the plunger 160 of the syringe 128 may be provided with a laterally directed protrusion (not shown) adapted to engage an inward protrusion (not shown) on the deformable detent 180 at or near the end of the downward stroke of the plunger 128. This interaction causes the resilient deformable detent 180 to move out of alignment with the socket 182 in an automated manner. At this point, the housing 112 is free to displace longitudinally along the actuator assembly 124, so that when the user releases the downward pressure on the skin, the leaf spring 166, when compressed between the closed top end 114 of the housing 112 and the actuator assembly 124, acts to reverse the longitudinal displacement between the housing 112 and the actuator assembly 124, assisting in pushing the housing 112 upward and away from the skin.

[0050] 12 and 13, an automatic injection system according to a further alternative embodiment of the present invention is shown and generally designated 210. In this alternative embodiment, like components are given like reference numerals and perform like functions unless otherwise specified. The injection system 210 includes a hollow housing 212 defining a handle, an injection head 218 located at a lower end 216 of the housing 212, and an actuator assembly 224 located inside the housing 212. The injection head 218 operates as previously described herein, including a pair of jaws 220 that are laterally displaceable relative to one another in response to relative movement between the actuator assembly 224 and the housing 212. The actuator assembly 224 includes a stationary frame 226 that carries a syringe 228, as previously described herein, and liquid medication is dispensed from the jaws 220 in essentially the same manner as described with respect to the previous embodiment. Unlike the previous embodiment, however, frame 226 is fixed relative to housing 212, and actuator assembly 224 further includes a pair of actuator plates 224a, each positioned or captured between an inner wall of housing 212 and frame 226, and longitudinally displaceable relative to housing 212. This relative longitudinal displacement is most clearly seen in Figures 13b and 13c, where the visible actuator plates 224a are positioned in undeployed and deployed states, respectively. Actuator plates 224a are fixed to an upper end 214 of housing 212, which is telescopically displaceable within housing 212 to effect longitudinal displacement between actuator assembly 224 and dispensing head to effect relative transverse displacement of jaws 220.

[0051] Accordingly, each jaw 220 is provided with a cam 244 formed therein and a corresponding follower 252 protruding from a corresponding portion of a respective actuator plate 224a. It will thus be appreciated that depression of top end 214 into housing 212 causes actuator plate 224a to undergo longitudinal displacement relative to housing 212, which in turn causes follower 252 to drive cam 44 downward, resulting in relative transverse displacement of jaws 220. Actuator assembly 224 includes guide members in the form of a pair of ramps 270 protruding from an inner wall of top end 214 of housing 212 into a position to engage and displace a free end of frame 226 in response to longitudinal displacement of actuator assembly 224 relative to housing 212, and as described herein above with respect to the first disclosed embodiment. This releases the spring-loaded syringe, thereby injecting the liquid medicament as described herein above. The free end of the frame 226 is preferably provided with locking elements in the form of notches or recesses 288 that are positioned and dimensioned to receive the thickness or upper ends of the respective ramps 270 once the upper end 214 of the housing 112 is fully depressed, thereby acting in a ratcheting manner to prevent reverse displacement of the upper end 214 and actuator plate 224a. After injection, the jaws 220 may be manually reversed relative to one another to allow the injection system 210 to be disengaged from the skin.

[0052] 14-16, an automatic injection system according to a further alternative embodiment of the present invention is shown, generally designated 310. In this alternative embodiment, like components are given like reference numerals and, unless otherwise specified, perform like functions. Unlike the previous two embodiments, injection system 310 is intended to be at least partially reusable and includes a hollow housing 312 in which an actuator assembly 324, which carries an injection head 318 that operates essentially as previously described herein, is removably positionable. A syringe 328 of liquid medication is secured within actuator assembly 324 and is in fluid communication with one or more microneedles 322 that protrude from a pair of jaws 320 of injection head 318. However, housing 312 is provided with one or more motors (not shown) and associated power sources, such as batteries (not shown), operable to effect lateral displacement of jaws 320 to insert microneedles 322 and depress the plunger of syringe 328. As a result, jaws 320 remain longitudinally fixed relative to housing 312 , such that the housing is only subject to longitudinal displacement relative to actuator assembly 324 , and particularly syringe 328 .

[0053] The housing 312 includes a first control or button 390 that, when depressed, may activate a motor (not shown) to effect lateral displacement of the jaws 320 to insert the microneedle 322. The injection system 310 may then automatically depress the plunger of the syringe 328, again using a suitable motor (not shown), to inject the medication. Once the medication has been injected, the injection system 310 may be operable, for example by one or more microswitches or sensors (not shown), to automatically reverse the lateral displacement of the jaws 320 to retract the microneedle 322 and disengage the injection system 310 from the injection site. The injection system 310 preferably includes a second button 392 that, when depressed, releases the actuator assembly 324 and injection head 318 from the housing 312, allowing the actuator 324 to be replaced with a new syringe 328 of medication. The housing 312 may include built-in circuitry (not shown) and appropriate components to facilitate wireless communication with either a phone-based app, a cloud-based server, or both, for automatic logging of injection performance and frequency to enable assessment of patient compliance and / or injection performance issues.

[0054] 17-20, an automatic injection system according to another alternative embodiment of the present invention is shown, generally designated 410. In this embodiment, like components are given like reference numerals and perform like functions unless otherwise specified. The injection system 410 comprises a hollow housing 412 defining a handle, an injection head 418 located at a lower end 416 of the housing 412, and an actuator assembly (not shown) located within the housing 412. The injection head 418 operates as previously described herein with a first action phase including a pair of jaws 420 that are laterally displaceable relative to one another in response to relative motion between the actuator assembly (not shown) and the housing 412. The actuator assembly comprises a stationary frame carrying a syringe as previously described herein, and liquid medicament is dispensed from a microneedle protruding from the jaws 420 in essentially the same manner as described with respect to the previous embodiment.

[0055] Unlike the previous embodiment, the housing 412 includes an outer sleeve 412a that surrounds the main housing 412 and is longitudinally telescopically displaceable a fixed distance thereon. The sleeve 412a extends substantially the length of the main housing 412 and is shaped and dimensioned to be grasped by a user to effect operation of the injection system 410 as previously described herein. The sleeve 412a is disposed and mechanically secured in a first position relative to the housing 412, as shown in FIGS. 17, 18, and 19. The sleeve 412a is secured in this first or upper position during an initial translational displacement of the pair of jaws 420, as shown in FIG. 19, thereby inserting the microneedle into the skin. Once the drug has been injected from the microneedle, the sleeve 412a is automatically mechanically released to allow longitudinal telescopic displacement relative to the housing 412 to a second or lower position. This movement is only a fixed distance in the direction towards jaw 420, so that the user's continued pressure of sleeve 412a against the skin will result in sleeve 412a being displaced downward along housing 412.

[0056] The injection system 410 includes a release member in the form of a pair of buttons 476, each coupled to or integrally formed with a respective one of the jaws 420 within the housing 412, and positioned within the housing 412 until the jaws 420 are displaced laterally, at which point the buttons 476 project outwardly through the housing 412 and onto opposite sides thereof, as seen in FIG. 19. Each button 476 has a tapered profile that increases in width in the direction toward the jaws 420. With the housing 412a in the raised or first position, as seen in FIG. 19, the buttons 476 are displaced laterally out of the housing 412, with the thin upper end of each button 476 positioned just below the lower edge or rim of the sleeve 412a. As the sleeve 412a is then displaced downward relative to the housing 412, its lower edge contacts the buttons 476, and continued downward displacement of the sleeve 412a forces each button back into the housing 412, resulting in a corresponding lateral or transverse displacement of the jaws 420 back to their non-deployed positions. This then disengages the microneedles from the skin, allowing the injection system 410 to be removed and preferably discarded. The sleeve 412a is preferably mechanically prevented from returning to its upper or first position, thereby preventing the injection system 410 from being reused.

[0057] 21-24, an automatic injection system according to a further alternative embodiment of the present invention is shown and generally designated 510. In this embodiment, like components are given like reference numerals and perform like functions unless otherwise specified. The injection system 510 includes a hollow housing 512 defining a handle, an injection head 518 located at a lower end 516 of the housing 512, and an actuator assembly 524 located within the housing 512. The injection head 518 includes a pair of jaws 520 that are laterally displaceable relative to one another in response to relative movement between the actuator assembly 524 and the housing 512. The actuator assembly 524 further houses a syringe 528, as previously described herein, containing a liquid medicament to be dispensed from a microneedle projecting from the jaws 520.

[0058] Unlike the previous embodiments, the actuator assembly 524 is tubular in form and rotatable in response to relative longitudinal displacement between the housing 512 and the actuator assembly 524 caused by a user placing the injection head 518 against the skin and pushing downward using the housing 512 as a handle, as described previously herein with reference to the earlier embodiments. The housing 512 includes a pair of opposing detents 515 that protrude from an inner surface of the housing 512 and are captured in respective helical grooves 517 formed in the outer surface of the actuator assembly 524. Thus, linear relative displacement is translated into rotational displacement of the actuator assembly 524. It will be understood that the positions of the detents 515 and helical grooves 517 may be reversed.

[0059] Dispensing head 518 is coupled to actuator assembly 524 but is not rotatable therewith; rather, dispensing head 518 remains aligned with housing 512 as head 518 moves through its open end 516. Actuator assembly 524 includes a pair of longitudinally extending pins or followers 550 that protrude from a lower end of actuator assembly 524, each of which seats in an elongated, substantially radially extending cam or slot 544 formed in each jaw 520. During downward depression of housing 512 by a user, followers 550 rotate with actuator assembly 524 from a first or undeployed position, shown in FIG. 23 , to a second or deployed position, shown in FIG. 24 . Relative movement between followers 550 and cams or slots 544 results in lateral displacement of jaws 520 relative to one another. The actuator assembly 524 may be configured to rotate in a first direction to transition the jaws 520 from the undeployed state to the deployed state, i.e., from the state shown in Figure 23 to the state shown in Figure 24, through a first action phase. A second action phase may result in the actuator assembly 524 rotating in the opposite direction, returning the jaws to the undeployed state after dispensing the medication, thereby allowing the injection system 510 to be removed from the skin.

[0060] Thus, the actuator assembly 524 is configured to translate linear displacement of the housing 512 into rotational displacement of the actuator assembly 524 relative to the housing 512. This rotational displacement can then be translated into linear transverse displacement of the pair of jaws 520 in a first direction to engage the microneedle, and in a second, opposite direction to disengage the microneedle. The rotational displacement of the actuator assembly 524 can also be used to actuate a syringe to dispense a drug therefrom.

[0061] The injection systems 10, 110, 210, 310, 410, 510 of the present invention provide a means of delivering intradermal injections that is simple, reliable, reproducible and essentially painless for the user as a result of the use of microneedles.

Claims

1. an actuator assembly disposed within the housing and longitudinally displaceable relative to the housing; an injection head attached to the actuator assembly and projecting from a lower open end of the housing, the injection head including a pair of jaws displaceable relative to one another in a direction transverse to a longitudinal axis of the housing in response to the relative longitudinal displacement between the housing and the actuator assembly, each jaw having one or more hollow microneedles projecting therefrom; a reservoir of liquid contained within the housing in fluid communication with one or more of the hollow microneedles; and a dispenser operable to pressurize the fluid in the reservoir in response to the relative longitudinal displacement between the housing and the actuator assembly to dispense the liquid from the one or more hollow microneedles.

2. 2. The automatic injection system of claim 1, wherein the reservoir is defined by a syringe including a cylinder closed at one end by a piston displaceable within the cylinder by the dispenser to pressurize the fluid.

3. 3. The automatic injection system of claim 2, wherein the dispenser includes a spring-loaded plunger in operative communication with the piston.

4. 4. The automatic injection system of claim 3, wherein the plunger includes an abutment, and the actuator assembly includes a latch member to which the abutment is releasably retained.

5. 5. The automatic injection system of claim 4, wherein the actuator assembly is operable to effect disengagement of the abutment and the latch member before or after completion of the relative lateral displacement of the pair of jaws.

6. 6. The automatic injection system of claim 5, wherein the actuator assembly includes a biasing element arranged to bias disengagement of the abutment and the latch member sequentially and / or following the relative longitudinal displacement between the housing and the actuator assembly.

7. 7. The automatic injection system of claim 6, wherein the biasing element includes a guide member fixed to the housing and displaceable relative to the latch member in response to the relative longitudinal displacement between the housing and the actuator assembly to bias disengagement of the abutment and the latch member.

8. 10. The automatic injection system of claim 9, wherein one of the jaws and the housing includes a cam and another of the jaws and the housing includes a corresponding follower, the cam having a profile arranged to effect the relative lateral displacement of the pair of jaws in response to the relative longitudinal displacement between the housing and the actuator assembly.

9. 9. The automatic injection system of claim 8, wherein each jaw includes a cam and the housing includes a corresponding pair of followers.

10. 10. An automatic injection system according to any preceding claim, wherein the actuator is arranged to undergo rotational displacement in response to linear displacement relative to the housing.

11. 20. The automatic injection system of claim 19, wherein the injection head is operable to translate the rotational displacement of the actuator assembly into the relative lateral displacement of the pair of jaws.

12. 10. An automatic injection system according to any preceding claim, wherein the injection head includes at least one release member manually operable to reverse the relative lateral displacement between the pair of jaws.

13. 13. The automatic injection system of claim 12, wherein the housing includes an aperture in a sidewall through which the release member is accessible after the relative longitudinal displacement between the housing and the actuator assembly.

14. 14. The automatic injection system of claim 12 or 13, comprising a longitudinally displaceable sleeve on the housing displaceable into engagement with the at least one release member to reverse the relative lateral displacement between the pair of jaws.

15. 10. An automatic injection system according to any preceding claim, including a locking element operable to prevent reversal of the relative longitudinal displacement between the housing and the actuator assembly.

16. 10. An automatic injection system according to any preceding claim, wherein the actuator assembly includes an elongate frame around which the housing is supported, within which the reservoir is housed, and the injection head is attached to an end of the frame.

17. 10. The automatic injection system of any preceding claim, wherein the hollow microneedles on each jaw are angled towards the hollow microneedles on the other jaw.

18. 10. An automatic injection system according to any preceding claim, comprising a releasable and securable cap around the lower end of the housing to enclose the injection head.

19. 10. An automatic injection system according to any preceding claim, including a spring arranged to bias the housing longitudinally of the actuator assembly.

20. 20. The automatic injection system of claim 19, wherein the spring comprises a leaf spring disposed between the actuator assembly and the closed end of the housing.

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