Reusable automatic injection device with pivoting spring loading

Abstract

A reusable automatic injection device is provided that includes a syringe housing configured to receive a pre-filled syringe and an injection device body connected to the syringe housing and pivotable between a closed position and an open position. The injection device body includes a slider housing and a slider assembly located within the slider housing and axially movable relative to the slider housing between a first position and a second position. The slider assembly includes a guide pin on which a spring is positioned that is actuatable between an extended state and a compressed state. The spring is in an extended state when the slider assembly is in the first position, and the spring is in a compressed state when the slider assembly is in the second position. A pair of connecting rods pivotally connect the syringe housing to the injection device body and interact with the slider assembly to actuate the spring to a compressed state when the injection device body is pivoted to the open position.

Description

Technical Field

[0001] The present disclosure relates generally to a drug delivery device and, more particularly, to a reusable automatic injection device having a pivoting spring-loaded design for facilitating injection. Background Art

[0002] Drug delivery devices, such as automatic injection devices (i.e., "auto-injectors"), are used to administer a medicament to a patient. Some types of automatic injection devices are designed as disposable or single-use devices that can only be used to deliver one dose of a drug, with the syringe then being discarded after use. Other types of automatic injection devices are designed as reusable injection devices, which are typically designed to allow a user to load and unload a standard pre-filled syringe into and from the reusable injection device.

[0003] While current reusable automatic injection devices are effective in delivering a medicament to a patient, they often have a complex design that makes the use of the automatic injection device difficult. For example, current reusable automatic injection devices often include a separate syringe housing and injection device body that require an initial separation step, and then the patient needs to perform the following separate steps: (1) "activate" the injection device body by compressing a feature on the injection device body; (2) insert the syringe into the syringe housing; and (3) reassemble the syringe housing and injection device body (e.g., screwing the components together). Therefore, this multi-step process of preparing an automatic injection device is considered to be complex and not user-friendly enough for daily use by patients.

[0004] Therefore, there is a need in the art for a reusable drug delivery device, such as a reusable autoinjector, having a simplified design that reduces the number of steps required to assemble and use the autoinjector, thereby improving the user experience of the device. Summary of the invention

[0005] A reusable automatic injection device for drug delivery is provided herein. The automatic injection device includes: a syringe housing having a proximal end and a distal end and defining an internal carrier configured to receive a prefilled syringe therein; and an injection device body pivotably connected to the syringe housing, the injection device body being pivotable between a closed position and an open position, in which the injection device body is aligned with the syringe housing, and in which the injection device body is rotated relative to the syringe housing. The injection device body also includes: a slider housing having a proximal end and a distal end, the distal end of the slider housing being pivotally coupled to the proximal end of the syringe housing via a pivot member; a slider assembly located within the slider housing and capable of axially moving relative to the slider housing between a first position and a second position, the slider assembly including a guide pin configured to guide movement of the slider assembly within the slider housing; and a spring located on the guide pin and capable of actuating between an extended state and a compressed state, wherein the spring is in the extended state when the slider assembly is in the first position, and in the compressed state when the slider assembly is in the second position, and wherein the spring drives the slider assembly to return distally from the second position to the first position when transitioning from the compressed state to the extended state. The automatic injection device also includes a pair of connecting rods connecting the syringe housing to the injection device body, wherein the pair of connecting rods are pivotable relative to each of the syringe housing and the injection device body, wherein the pair of connecting rods interact with the slider assembly so that the spring is actuated to a compressed state when the injection device body is pivoted to the open position.

[0006] In certain configurations, the slide housing defines a central channel therein for receiving a guide pin and a spring, and wherein a proximal end of the central channel includes a spring retaining member and a deflectable hook structure located thereon, wherein the spring retaining member is configured to retain the spring within the central channel, and wherein the deflectable hook structure is configured to interact with the slide assembly.

[0007] In certain configurations, the sliding member assembly includes a distal end and a proximal end, wherein a guide pin extends between the distal end and the proximal end, and wherein the sliding member assembly also includes a cylindrical end member located at the distal end of the sliding member assembly, the cylindrical member having a closed bottom surface and defining a chamber therein, wherein the guide pin extends proximally from the closed bottom surface and extends through the chamber to the proximal end of the sliding member assembly; a step portion, the step portion extending radially outward from the cylindrical end member at the top surface of the cylindrical end member; and a tongue structure, the tongue structure formed on the guide pin adjacent to the proximal end of the sliding member assembly, the tongue structure being configured to engage with the deflectable hook structure when the sliding member assembly is moved to the second position to lock the sliding member assembly in the second position and lock the spring in a compressed state.

[0008] In certain configurations, the distal end of the spring is positioned within the cavity of the cylindrical end member to hold the spring in place and enable compression of the spring when the slide assembly moves from the first position to the second position.

[0009] In certain configurations, the slider housing includes an inner surface having a pair of axial channels formed therein, the pair of axial channels being positioned on opposite sides of the slider housing, and wherein the injection device body further includes a roller positioned in each of the pair of axial channels so as to be axially movable along the axial channels, wherein a corresponding connecting rod of the pair of connecting rods is pivotally connected to each roller such that the pair of connecting rods causes the roller to translate axially along the pair of axial channels.

[0010] In certain configurations, the roller abuts a stepped portion of the slider assembly such that axial translation of the roller by the pair of connecting rods causes the slider assembly to move axially within the slider housing.

[0011] In certain configurations, when the slider assembly moves to the second position, the tongue structure engages the deflectable hook structure such that when the injection device body is rotated from the open position to the closed position, the slider assembly is locked in the second position and the spring is locked in a compressed state.

[0012] In certain configurations, the injection device body further comprises a trigger cap at the proximal end of the slider housing, wherein the trigger cap interacts with the slider assembly when depressed so as to disengage the tongue structure from the deflectable hook structure, thereby unlocking the slider assembly and the spring and enabling the spring to transition from a compressed state to an extended state and causing the slider assembly to move from the second position to the first position.

[0013] In certain configurations, the inner carrier includes an elongated channel formed within the syringe housing, and wherein a proximal opening of the elongated channel is exposed when the injection device body is in the open position to enable loading of a prefilled syringe into the elongated channel.

[0014] In certain configurations, with the injection device body in the closed position, the closed bottom surface of the cylindrical end member abuts the proximal end of the plunger rod of the pre-filled syringe when loaded in the syringe housing.

[0015] In certain configurations, the automatic injection device further comprises: a syringe housing spring located within the elongated channel and configured to surround the barrel of the prefilled syringe when inserted into the elongated channel; and a needle cover having a proximal end, a distal end including an opening, and a sidewall located therebetween, the needle cover being displaceable by the syringe housing spring between a pre-use position, a use position, and a post-use position, in which the needle cover surrounds the needle, a use position in which the needle extends through the opening in the distal end of the needle cover, and a post-use position in which the needle cover surrounds the needle.

[0016] In certain configurations, when transitioning from a compressed state to an extended state, the spring generates a force sufficient to cause the needle of the pre-filled syringe to pierce the dermal surface of the patient and cause the medication within the pre-filled syringe to be dispensed.

[0017] In certain configurations, the injection device body is rotated more than 90 degrees relative to the syringe housing when in the second position.

[0018] In certain configurations, the pair of connecting rods are connected to the syringe housing via a pair of rod pivot pins on an outer surface of the syringe housing.

[0019] In certain configurations, the slide housing includes a seat formed within its internal volume, and wherein the slide assembly further includes a pair of retaining arms connected to the step and extending proximally therefrom, each of the pair of retaining arms including a hooked proximal end that engages the seat when the slide assembly is in the first position to prevent further distal travel.

[0020] In certain configurations, the pair of connecting rods converts rotational motion of the injection device body into linear motion of the slide assembly.

[0021] The present invention also provides a drug delivery device, which includes an automatic injection device and a prefilled syringe. The prefilled syringe is at least partially received in the inner carrier of the syringe housing, and the prefilled syringe includes: a syringe barrel, the syringe barrel includes a proximal end, a distal end and a side wall defining an interior containing a medicament; a needle, the needle is arranged at the distal end of the syringe barrel and is in fluid communication with the syringe interior; and a plunger assembly, the plunger assembly is movable within the syringe interior and includes a plunger rod and a stopper, the stopper is arranged at the distal end of the plunger rod.

[0022] In certain configurations, when the prefilled syringe is at least partially received within the inner carrier of the syringe housing, the proximal end of the plunger rod extends proximally beyond the syringe housing to extend into the slider housing when the injection device body is in the closed position.

[0023] In certain configurations, when the injection device body is in the closed position, the slider assembly is in the second position, and the spring is in the compressed state, the closed bottom surface of the cylindrical end member abuts the proximal end of the plunger rod.

[0024] In certain configurations, when the trigger cap is depressed and thereby enables the spring to transition from a compressed state to an extended state and cause the slide assembly to move from the second position to the first position, the closed bottom surface of the cylindrical end member advances the plunger rod distally into the interior of the syringe to cause injection of the medicament. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1A is a front view of a drug delivery device in an initial closed position according to a non-limiting embodiment described herein;

[0026] Figure 1B is in the open position Figure 1A A front view of a drug delivery device;

[0027] Figure 1C Injection closed position Figure 1A A front view of a drug delivery device;

[0028] Figure 2A yes Figure 1A A front cross-sectional view of a drug delivery device;

[0029] Figure 2B yes Figure 1A A side cross-sectional view of a drug delivery device;

[0030] Figure 3 yes Figure 1B A front cross-sectional view of a drug delivery device;

[0031] Figure 4A It is in the position before injection Figure 1C A front cross-sectional view of a drug delivery device;

[0032] Figure 4B It is in the position before injection Figure 1C A side cross-sectional view of a drug delivery device;

[0033] Figure 5A It is in the post-injection position Figure 1C A front cross-sectional view of a drug delivery device; and

[0034] Figure 5B It is in the post-injection position Figure 1C Side cross-sectional view of a drug delivery device. DETAILED DESCRIPTION

[0035] The following description is provided to enable those skilled in the art to make and use the described embodiments contemplated for implementation of the present invention. However, various modifications, equivalents, variations and substitutions will still be apparent to those skilled in the art. Any and all such modifications, variations, equivalents and substitutions are intended to fall within the spirit and scope of the present invention.

[0036] For the purposes of the following description, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and their derivatives shall relate to the orientation of the present invention as shown in the accompanying drawings. However, it should be understood that the present invention may adopt various alternative variations unless expressly specified to the contrary. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Therefore, specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered limiting.

[0037] As used in this specification, the words "proximal" and "distal" refer to directions closer to and farther from a user who places the device in contact with another component or a patient, respectively. Thus, for example, the end of the device that first contacts another component or the patient's body would be the distal end, while the opposite end of the device that is being manipulated by the user would be the proximal end of the device.

[0038] The terms "first", "second", etc. are not intended to refer to any particular sequence or chronology, but rather to different conditions, attributes or elements.

[0039] Steering Figures 1A-1C , shows a drug delivery device 10 that includes an automatic injection device 12 and a prefilled syringe 14 that can be loaded into the automatic injection device 12 for administering a medicament to a patient. The automatic injection device 12 can be characterized as generally including: a syringe housing 16 for receiving the prefilled syringe 14; an injection device body 18 that interacts with the syringe housing 16 and the prefilled syringe 14 to facilitate injection of the medicament; and a pair of connecting rods 20 that couple the syringe housing 16 to the injection device body 18, wherein the pair of connecting rods 20 function to achieve pivotal spring loading of the injection device body 18 when the injection device body 18 is rotated relative to the syringe housing 16, as described in further detail below. In operation, the automatic injection device 12 can be moved from an initial closed position ( ) in which the injection device body 18 is aligned with the syringe housing 16. Figure 1A) is pivoted to an open position in which the injection device body 18 is rotated relative to the syringe housing 16 ( Figure 1B ) and returns to the closed position ( Figure 1C ) to perform the injection (i.e., close the injection site).

[0040] Reference now Figure 2A-5B , showing front and side cross-sectional views of the drug delivery device 10 during various stages of operation of the device, including in an initial closed position ( Figure 2A and Figure 2B ), in the open position ( Figure 3 ), in the loading closed position ( Figure 4A and Figure 4B ), and in the discharge / unloading closed position ( Figure 5A and Figure 5B ).

[0041] like Figure 2A-5B As shown, the syringe housing 16 is disposed at the distal end 22 of the drug delivery device 10. The syringe housing 16 has a proximal end 24 and a distal end 26 and defines an internal carrier 28 within which the prefilled syringe 14 can be loaded, wherein the internal carrier 28 defines an elongated channel 30 within the syringe housing 16. Figure 3 As shown clearly, the prefilled syringe 14 includes a barrel 32 having a proximal end 34 and a distal end 36 and defining an interior 38 configured to hold one or more medicaments therein. A needle 40 may be fixed to the distal end 36 of the barrel 32, and a stopper 42 may be slidably received within the interior 38 of the barrel 32 to allow the one or more medicaments to be expelled through the needle 40. The stopper 42 may be displaced by a plunger rod 44 under the influence of the injection device body 18, as described in further detail below. The plunger rod 44 has a proximal end 46 that may be actuated by the injection device body 18 and a distal end 48 configured to engage the stopper 42.

[0042] When loading the prefilled syringe 14 into the syringe housing 16, the injection device body 18 can be rotated to the open position to expose the proximal opening 50 of the elongated channel 30 and enable the prefilled syringe 14 to be loaded into the elongated channel 30. With the channel 30 of the inner carrier 28 exposed, the syringe 32 is placed within the inner carrier 28. The prefilled syringe 14 is received within the inner carrier 28 such that the plunger rod 44 extends beyond the proximal end 24 of the syringe housing 16, thereby providing interaction of the injection device body 18 with the syringe 14.

[0043] According to aspects of the present disclosure, a displaceable needle cover 52 may be disposed at the distal end 26 of the syringe housing 16. The needle cover 52 may include a tubular distal portion 54 configured to enclose the needle 40 and one or more arms 56 extending proximally from the tubular distal portion 54. The needle cover 52 may be displaced in a telescopic manner relative to the syringe housing 16 from a pre-use position, in which the needle cover 52 extends a first distance beyond the distal end 26 of the syringe housing 16 and encloses the needle 40 of the syringe 14, to a use position, in which the needle cover 52 is displaced proximally, thereby exposing the needle 40, to a post-use position, in which the needle cover 52 extends a second distance beyond the distal end 26 of the syringe housing 16 and encloses the needle 40. The needle cover 52 may be biased to the distal position by a needle cover spring 58. In the post-use position, the needle cover 52 is locked, and the needle 40 cannot be exposed again.

[0044] According to aspects of the present disclosure, the injection device body 18 includes: a slider housing 60 having a proximal end 62 and a distal end 64; a slider assembly 66, which is located in the slider housing 60 and can move axially relative to the slider housing 60; a roller 68, which is engaged with the slider assembly 66 and the slider housing 60; and a trigger cap 70, which is located at the proximal end 62 of the slider housing 60, wherein the trigger cap 70 is configured to interact with the slider assembly 66 when pressed.

[0045] The distal end 64 of the slider housing 60 is pivotally coupled to the proximal end 24 of the syringe housing 16 via a pivot member 72, such as a pivot pin that couples the slider housing 60 to the syringe housing 16, about which the slider housing 60 rotates relative to the syringe housing 16. The pivot member 72 provides for rotation of the slider housing 60 (and the entire injection device body 18) relative to the syringe housing 16, wherein the rotation is provided between a closed position in which the injection device body 18 is aligned with the syringe housing 16 and an open position in which the injection device body 18 is rotated relative to the syringe housing 16 to provide access to the interior carrier 28 of the syringe housing 16 and allow the prefilled syringe 14 to be inserted therein. In some embodiments, when in the open position, the slider housing 60 (and the entire injection device body 18) can be rotated more than 90 degrees relative to the syringe housing 16.

[0046] The slider housing 60 includes an inner surface 74 having a plurality of features that interact with other components of the injection device body 18. The inner surface 74 of the slider housing 60 may include a pair of axial channels 76 formed therein on opposite sides of the slider housing 60 within which the roller 68 may translate during operation of the automatic injection device 12. The slider housing 60 may also include a seat 78 formed thereon that limits travel of the slider assembly 66 within the slider housing 60. The inner surface 74 of the slider housing 60 also defines a central passage 80 therein within which portions of the slider assembly 66 may move relative to the slider housing 60, wherein a proximal end of the central passage 80 includes a spring retaining member 82 and a deflectable hook structure 84 configured to interact with the slider assembly 66 as explained in further detail below.

[0047] The slider assembly 66 of the injection device body 18 is positioned within and extends longitudinally therein, with a distal end 86 of the slider assembly 66 located near the distal end 64 of the slider housing 60 and a proximal end 87 of the slider assembly 66 located near the proximal end 62 of the slider housing 60. The slider assembly 66 includes a guide pin 88, a spring 90, a cylindrical end member 92, a step 94, and a pair of retaining arms 96.

[0048] In an exemplary embodiment, the guide pin 88, the cylindrical end member 92, the step 94 and the retaining arms 96 are formed as a single integral member, which may include, for example, a molded component. The cylindrical end member 92 is positioned at the distal end 86 of the slider assembly 66, wherein the cylindrical end member 92 has a closed bottom surface 98 and defines a chamber 100 therein, and wherein the chamber 100 receives a portion of the spring 90 therein. The guide pin 88 extends proximally from the closed bottom surface 98 (from the distal end 86 of the slider assembly 66) and extends through the chamber 100 to the proximal end 87 of the slider assembly 66. The step 94 of the slider assembly 66 extends radially outward from the cylindrical end member at the top surface of the cylindrical end member 92, wherein the pair of retaining arms 96 are connected to the step 94 and extend proximally therefrom. Each of the retaining arms 96 includes a hooked proximal end 101 that engages the seat 78 of the slider housing 60 when the slider assembly 66 is in the first position to prevent further distal travel of the slider assembly 66, as explained in greater detail below.

[0049] The guide pin 88 of the slider assembly 66 extends between the distal end 86 and the proximal end 87 of the slider assembly 66 and is configured to guide the movement of the slider assembly 66 within the slider housing 60 - wherein the slider assembly 66 can be in a first position ( Figure 2A and Figure 2B as well as Figure 5A and Figure 5B ) and the second position ( Figure 3 as well as Figure 4A and Figure 4B ) between the second position and the first position, wherein the second position is distal to the first position. The spring 90 is positioned on the guide pin 88 and is capable of being moved axially in the extended state ( Figure 2A and Figure 2B as well as Figure 5A and Figure 5B ) and compressed state ( Figure 3 as well as Figure 4A and Figure 4B ), wherein the spring retaining member 82 acts as a stop to hold the spring 90 in place. In operation of the automatic injection device 12, the spring 90 is in an extended state when the slider assembly 66 is in the first position, and in a compressed state when the slider assembly 66 is in the second position. The spring 90 is operable to drive the slider assembly 66 distally from the second position back to the first position when it is converted from the compressed state to the extended state. A tongue structure 102 is formed on the guide pin 88 adjacent to the proximal end 87 of the slider assembly 66, wherein the tongue structure 102 is configured to engage with the deflectable hook structure 84 of the slider housing 60 when the slider assembly 66 moves to the second position. That is, when the slider assembly 66 moves to the second position, the tongue structure 102 is positioned proximal to the deflectable hook structure 84 and supported by the back / proximal side of the deflectable hook structure 84 so as to lock the slider assembly 66 in the second position and hold the spring 90 in a compressed state when the injection device body 18 is rotated from the open position to the closed position. In accordance with an embodiment, the tongue structure 102 can be configured as a disc-shaped protrusion extending radially from the guide pin 88, and the back / proximal side of the deflectable hook structure 84 can have a horizontal surface for retaining the disc-shaped protrusion, but it should be recognized that the tongue structure 102 and / or the deflectable hook structure 84 can have other suitable shapes.

[0050] The rollers 68 of the injection device body 18 are located in a pair of axial channels 76 formed in the slider housing 60, wherein a corresponding roller 68 is positioned in each of the axial channels 76. The rollers 68 are configured to be able to move axially along the axial channels 76. When the injection device body 18 is rotated relative to the syringe housing 16, the movement of the rollers 68 is achieved by the rotation of the connecting rods 20, because the first end of each connecting rod 20 is pivotally connected to the syringe housing 16 (e.g., on the outer surface of the syringe housing 16, such as via a pair of rod pivot pins 106) and the second end of each connecting rod 20 is pivotally connected to the corresponding roller 68 (e.g., wherein the rounded end is positioned around a portion of the roller 68). Therefore, the collection of connecting rods 20 and rollers 68 effectively operates as a slider-crank mechanism, wherein the rotation of the connecting rod 20 (i.e., the "crank") is converted into linear movement of the rollers 68 (i.e., the "slider") along the pair of axial channels 76 within the slider housing 60. The roller 68 is positioned within the channel 76 to be distal to the step 94 of the slider assembly 66, wherein when the automatic injection device 12 is transitioned from the initial closed state to the open state, the roller 68 abuts the step 94, so that the axial translation of the roller 68 in the proximal direction causes the slider assembly 66 to also move proximally within the slider housing 60. More specifically, when the automatic injection device 12 is transitioned from the initial closed state to the open state (in response to the rotation of the injection device body 18 relative to the syringe housing 16), the connecting rod 20 is caused to rotate—wherein the rotation of the connecting rod 20 causes the roller 68 to move proximally within the channel 76, and the roller 68 in turn pushes against the slider assembly 66 and causes the slider assembly 66 to move proximally within the slider housing 60.

[0051] As described above, the trigger cap 70 is located at the proximal end 62 of the slider housing 60, wherein the trigger cap 70 is accessible at the proximal end of the injection device body 18 so that it can be pressed by the user. The trigger cap 70 extends internally into the slider housing 60 so that it can interact with the slider assembly 66 when pressed. That is, when the trigger cap 70 is pressed, the trigger cap 70 causes the deflectable hook structure 84 to move radially outward, wherein the radially outward movement of the deflectable hook structure 84 releases the tongue structure 102 from its position proximal to the deflectable hook structure 84 (i.e., releases the tongue structure 102 from the back / proximal side of the deflectable hook structure 84). With the tongue structure 102 released, the slider assembly 66 is unlocked and the spring 90 is able to transition from its compressed state to its extended state, which in turn causes the slider assembly 66 to move from the second position back to the first position and push the needle 40 of the prefilled syringe 14 into the patient's body and the plunger rod 44 further into the syringe 32 to dispense the medication.

[0052] Referring to the drawings, the activation of the drug delivery device 10 will now be described. The reusable automatic injection device 12 is arranged in an initial closed state ( Figure 1A as well as Figure 2A and Figure 2B ), in this initially closed state, the injection device body 18 is aligned with the syringe housing 16. The user can then grasp the automatic injection device 12 and cause the injection device body 18 to pivot relative to the syringe housing 16 to transition the automatic injection device 12 from the initially closed position to the open position ( Figure 1B and Figure 3 ). When pivoting to the open position, the injection device body 18 pivots about the pivot pin 72 that couples the slider housing 60 to the syringe housing 16. Once the automatic injection device 12 is in the open position (where the injection device body 18 is rotated more than 90 degrees relative to the syringe housing 16), the prefilled syringe 14 can be inserted into the syringe housing 16 and secured within the interior carrier 28 of the syringe housing 16 - with the proximal end of the syringe (i.e., the plunger rod 44) ​​extending beyond the proximal end 24 of the syringe housing 16.

[0053] When the automatic injection device 12 is transitioned from the initial closed position to the open position, the connecting rod 20 of the automatic injection device 12 is caused to rotate in association with the injection device body 18. The rotation of the connecting rod 20 causes the roller 68 located within the slider housing 60 of the injection device body 18 to move linearly in association - wherein the connecting rod 20 and the roller 68 thus function as a slider-crank mechanism in the automatic injection device 12. As the injection device body 18 rotates toward its open position, the roller 68 is caused to move proximally within the axial channel 76 of the slider housing 60, and this proximal movement of the roller 68 within the slider housing 60 pushes / causes the slider assembly 66 to also move proximally within the slider housing 60. That is, the roller 68 is caused to abut against the step 94 of the slider assembly 66, so that the axial translation of the roller 68 in the proximal direction causes the slider assembly 66 to also move proximally within the slider housing 60. As the injection device body 18 rotates to its open position, the slider assembly 66 is thereby caused to move proximally from the first position ( Figure 2A and Figure 2B ) moves proximally to a second position ( Figure 3 ).

[0054] As the slider assembly 66 moves toward its second position, the guide pin 88 translates within the central channel 80 of the slider housing 60. When the slider assembly 66 reaches the second position, the tongue structure 102 formed on the guide pin 88 is pressed against the deflectable hook structure 84 of the slider housing 60 and passes proximally past the deflectable hook structure 84 of the slider housing 60, so that the slider assembly 66 becomes locked in the second position. That is, when the slider assembly 66 moves to the second position, the tongue structure 102 is positioned proximally of the deflectable hook structure 84 and abuts against the back / proximal side of the deflectable hook structure 84 so as to lock the slider assembly 66 in the second position and keep the spring 90 in a compressed state when the injection device body 18 is rotated from the open position to the closed position.

[0055] Moreover, as the slider assembly 66 moves toward its second position, the spring 90 positioned about the guide pin 88 begins to compress from its extended position toward its compressed position. That is, the spring 90 is positioned between the spring retaining member 82 of the slider housing 60 (on the proximal end of the spring 90) and the closed bottom surface 98 of the cylindrical end member 92 (on the distal end of the spring 90), wherein the distal end of the spring 90 is retained within the chamber 100 of the cylindrical end member 92, so that the movement of the slider assembly 66 toward the second position causes the spring 90 to compress. When the slider assembly 66 reaches the second position, due to the interaction of the tongue structure 102 and the deflectable hook structure 84, the slider assembly 66 becomes locked in the second position, wherein the spring 90 is thereby also locked in its compressed state.

[0056] With the slide assembly 66 locked in the second position and its spring 90 "loaded" in its compressed state, the injection device body 18 can be rotated back from the open position to the closed position (i.e., the closed injection position, Figure 1C as well as Figure 4A and Figure 4B ). As the injection device body 18 is rotated back to the closed injection position, the slider assembly 66 is retained in the second position due to the interaction / locking of the tongue structure 102 with the deflectable hook structure 84, wherein the spring 90 is thereby also retained in its compressed state. When the injection device body 18 is rotated back to the closed injection position, the closed bottom surface 98 of the cylindrical end member 92 of the slider assembly 66 is positioned adjacent to the proximal end of the plunger rod 44 of the syringe 14, and in some embodiments, the closed bottom surface 98 can be in direct contact with the proximal end of the plunger rod 44.

[0057] When it is desired that the drug delivery device 10 perform an injection, the user can depress the trigger cap 70 of the automatic injection device 12. When the trigger cap 70 is depressed, the trigger cap 70 causes the deflectable hook structure 84 to move radially outward, wherein the radial outward movement of the deflectable hook structure 84 releases the tongue structure 102 from its position proximal to the deflectable hook structure 84, so that the slider assembly 66 becomes unlocked and the spring 90 can transition from its compressed state to its extended state. As the spring 90 transitions from its compressed state to its extended state, the slider assembly 66 moves from the second position back to the first position ( Figure 5A and Figure 5B ), wherein the hooked proximal end 101 on each of the retaining arms 96 engages the seat 78 of the slider housing 60 to stop movement of the slider assembly 66 at the first position.

[0058] When moving back toward the first position, the closed bottom surface 98 of the cylindrical end member 92 (of the slider assembly 66) applies a thrust against the proximal end of the prefilled syringe 14, that is, against the proximal end 46 of the plunger rod 44a. The force applied by the closed bottom surface 98 of the cylindrical end member 92 is sufficient to initially cause the needle 40 of the prefilled syringe 14 to pierce the dermal surface of the patient, and then subsequently push the plunger rod 44 further distally into the interior of the syringe barrel 32 to cause the medicament in the prefilled syringe 14 to be dispensed.

[0059] Advantageously, embodiments of the present disclosure thus provide a reusable automatic injection device for drug delivery. The automatic injection device includes a pivotable structure that automatically loads / compresses the spring of the automatic injection device as the automatic injection device is rotated and opened to introduce a prefilled syringe therein. The rotation of the automatic injection device (for introducing the syringe) and the spring compression are thus combined into a single step, which reduces the number of steps required to assemble and use the automatic injection device, thereby improving the user experience of the device.

[0060] Although the present invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it should be understood that these details are only for this purpose and the present invention is not limited to the disclosed embodiments, on the contrary, the disclosed embodiments are intended to cover modifications and equivalent arrangements that fall within the spirit and scope of the appended claims. For example, it should be understood that the present invention contemplates that one or more features of any embodiment can be combined with one or more features of any other embodiment to the extent possible.

Claims

1. A reusable automatic injection device for drug delivery, the automatic injection device comprising: a syringe housing having a proximal end and a distal end and defining an internal carrier configured to receive a prefilled syringe therein; an injection device body pivotably connected to the syringe housing, the injection device body being pivotable between a closed position in which the injection device body is aligned with the syringe housing and an open position in which the injection device body is rotated relative to the syringe housing, the injection device body comprising: a slider housing including a proximal end and a distal end, the distal end of the slider housing being pivotally coupled to the proximal end of the syringe housing via a pivot member; a slider assembly located within the slider housing and axially movable relative to the slider housing between a first position and a second position, the slider assembly including a guide pin configured to guide movement of the slider assembly within the slider housing; and a spring located on the guide pin and actuatable between an extended state and a compressed state, the spring being in the extended state when the slider assembly is in the first position and in the compressed state when the slider assembly is in the second position, and wherein the spring drives the slider assembly distally back from the second position to the first position when the spring transitions from the compressed state to the extended state; and a pair of connecting rods connecting the syringe housing to the injection device body, wherein the pair of connecting rods are capable of pivoting relative to each of the syringe housing and the injection device body, and wherein the pair of connecting rods interact with the slider assembly so that when the injection device body is pivoted to the open position, the spring is actuated to the compressed state.

2. The automatic injection device according to claim 1, wherein: The slider housing defines a central passage therein that receives the guide pin and the spring, and wherein a proximal end of the central passage includes: a spring retaining member thereon, the spring retaining member being configured to retain the spring within the central channel; and A deflectable hook structure is configured to interact with the slider assembly.

3. The automatic injection device according to claim 2, wherein: The slider assembly includes a distal end and a proximal end, the guide pin extends between the distal end and the proximal end of the slider assembly, and wherein the slider assembly further includes: a cylindrical end member at a distal end of the slider assembly, the cylindrical end member having a closed bottom surface and defining a cavity therein, wherein the guide pin extends proximally from the closed bottom surface and through the cavity to the proximal end of the slider assembly; a step extending radially outward from the cylindrical end member at a top surface of the cylindrical end member; and A tongue structure is formed on the guide pin adjacent to the proximal end of the slider assembly, the tongue structure being configured to engage with the deflectable hook structure when the slider assembly moves to the second position to lock the slider assembly in the second position and to lock the spring in the compressed state.

4. The automatic injection device according to claim 3, wherein: The distal end of the spring is positioned within the cavity of the cylindrical end member to hold the spring in place and to enable compression of the spring when the slide assembly moves from the first position to the second position.

5. The automatic injection device according to claim 3, wherein: The slider housing includes an inner surface having a pair of axial channels formed therein, the pair of axial channels being positioned on opposite sides of the slider housing, and wherein the injection device body further includes a roller located in each of the pair of axial channels so as to be axially movable along the axial channels, wherein a corresponding connecting rod of the pair of connecting rods is pivotally connected to each roller such that the pair of connecting rods causes the rollers to translate axially along the pair of axial channels.

6. The automatic injection device according to claim 5, wherein: The roller abuts the stepped portion of the slider assembly such that axial translation of the roller caused by the pair of connecting rods causes the slider assembly to move axially within the slider housing.

7. The automatic injection device according to claim 3, wherein: When the slider assembly moves to the second position, the tongue structure engages the deflectable hook structure such that when the injection device body is rotated from the open position to the closed position, the slider assembly is locked in the second position and the spring is locked in the compressed state.

8. The automatic injection device according to claim 3, wherein: The injection device body further comprises a trigger cap positioned at the proximal end of the slider housing, wherein the trigger cap interacts with the slider assembly when depressed to disengage the tongue structure from the deflectable hook structure, thereby unlocking the slider assembly and the spring and enabling the spring to transition from the compressed state to the extended state and causing the slider assembly to move from the second position to the first position.

9. The automatic injection device according to claim 3, wherein: The inner carrier included in the syringe housing defines an elongated channel within the syringe housing, and wherein a proximal opening of the elongated channel is exposed when the injection device body is in the open position to enable a prefilled syringe to be loaded into the elongated channel.

10. The automatic injection device according to claim 9, wherein: With the injection device body in the closed position, the closed bottom surface of the cylindrical end member abuts the proximal end of the plunger rod of the pre-filled syringe when the pre-filled syringe is loaded in the syringe housing.

11. The automatic injection device of claim 9, further comprising: a syringe housing spring positioned within the elongated channel and configured to surround the barrel of the prefilled syringe when inserted into the elongated channel; and A needle cover having a proximal end, a distal end including an opening, and a side wall located between the proximal and distal ends of the needle cover, the needle cover being displaceable by the syringe housing spring between a pre-use position in which the needle cover surrounds the needle, a use position in which the needle extends through the opening in the distal end of the needle cover, and a post-use position in which the needle cover surrounds the needle.

12. The automatic injection device according to claim 1, wherein: When transitioning from the compressed state to the extended state, the spring generates a force sufficient to cause the needle of the pre-filled syringe to pierce a dermal surface of a patient and cause the medicament within the pre-filled syringe to dispense.

13. The automatic injection device according to claim 1, wherein: When in the second position, the injection device body is rotated more than 90 degrees relative to the syringe housing.

14. The automatic injection device according to claim 1, wherein: The pair of connecting rods are connected to the syringe housing via a pair of rod pivot pins on an outer surface of the syringe housing.

15. The automatic injection device of claim 1, wherein: The slide housing includes a seat formed within an interior volume thereof, and wherein the slide assembly further includes a pair of retaining arms connected to and extending proximally from the step, each of the pair of retaining arms including a hooked proximal end that engages the seat when the slide assembly is in the first position to prevent further distal travel.

16. The automatic injection device of claim 1, wherein: The pair of connecting rods converts the rotational motion of the injection device body into linear motion of the slide assembly.

17. A drug delivery device comprising: The automatic injection device according to any one of claims 1 to 16; and a prefilled syringe at least partially received within the inner carrier of the syringe housing, the prefilled syringe comprising: a syringe barrel comprising a proximal end, a distal end, and a sidewall defining an interior for containing a medicament; a needle disposed at a distal end of the syringe barrel and in fluid communication with the syringe interior; and A plunger assembly is movable within the syringe and includes a plunger rod and a stopper disposed at a distal end of the plunger rod.

18. The drug delivery device of claim 17, wherein: The proximal end of the plunger rod extends proximally beyond the syringe housing when the prefilled syringe is at least partially received within the inner carrier of the syringe housing to extend into the slider housing when the injection device body is in the closed position.

19. The drug delivery device of claim 18, wherein: With the injection device body in the closed position, the slider assembly in the second position, and the spring in the compressed state, the closed bottom surface of the cylindrical end member abuts the proximal end of the plunger rod.

20. The drug delivery device of claim 19, wherein: When the trigger cap is depressed and thereby enables the spring to transition from the compressed state to the extended state and causes the slider assembly to move from the second position to the first position, the closed bottom surface of the cylindrical end member advances the plunger rod distally into the interior of the syringe to cause injection of the medicament.

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