Cross-reference to related applications for reusable auto-injector devices (with swivel spring load).

Abstract

A reusable auto-injector is provided, comprising a syringe housing configured to receive a pre-filled syringe, and an injector body connected to the syringe housing and pivotable between a closed position and an open position. The injector body includes a slider housing and a slider assembly located within the slider housing and axially movable between a first position and a second position. The slider assembly includes a guide pin having a spring positioned above it, which is actuated between an extended and a compressed state. The spring is extended when the slider assembly is in the first position and compressed when the slider assembly is in the second position. A pair of connecting rods pivotably connect the syringe housing to the injector body and interact with the slider assembly to actuate the spring to the compressed state when the injector body is pivoted to the open position.

Description

Technical Field

[0001] This application claims the priority of Chinese Application No. 202310860887.0, titled "Reusable Auto-Injector Device with Pivoting Spring Load", filed on July 13, 2023, the disclosure of which is incorporated herein by reference in its entirety.

Background Art

[0002] The present disclosure generally relates to drug delivery devices, and more specifically to reusable auto-injector devices having a pivoting spring load design for facilitating injection. Description of Related Art

[0003] Drug delivery devices such as auto-injector devices (i.e., "auto-injection") are used to administer drugs to patients. Some types of auto-injectors are designed as disposable or single-use devices and can only be used to deliver a single dose of drug, and the syringe is discarded after use. Other types of auto-injectors are designed as reusable injectors, and such reusable injectors are typically designed to allow the user to load and unload a standard pre-filled syringe therein.

[0004] While effective for delivering medication to patients, current reusable auto-injectors often have complex designs that make them difficult to use. For example, current reusable auto-injectors typically include separate syringe housings and injector bodies that require an initial separation step, after which the patient must perform separate steps of (1) "energizing" the injector body by compressing features on the injector body, (2) inserting the syringe into the syringe housing, and (3) reassembling the syringe housing and injector body (e.g., a step to screw the components together). Thus, this multi-step process of preparing the auto-injector is perceived as complex and not user-friendly for daily patient use.

[0005] Therefore, in this field, reusable drug delivery devices, such as reusable autoinjectors, need to have a simplified design that reduces the number of steps required for the assembly and use of the autoinjector, thereby improving the user experience of the device. [Overview of the Initiative]

[0006] Provided herein is a reusable auto-injector for drug delivery. The auto-injector includes a syringe housing that defines an internal carrier having a proximal and distal end and configured to receive a pre-filled syringe therein, and an injector body pivotably connected to the syringe housing, the injector body being pivotable between a closed position in which the injector body is aligned with the syringe housing and an open position in which the injector body is rotated relative to the syringe housing. The injector body further includes a slider housing having a proximal end and a distal end, the distal end of the slider housing being pivotably connected to the proximal end of the syringe housing via a pivot member, the slider assembly being located within the slider housing and movable axially relative to the slider housing between a first position and a second position, the slider assembly comprising a guide pin configured to guide the movement of the slider assembly within the slider housing, and a spring located on the guide pin and actuated between an extended state and a compressed state, the spring being extended when the slider assembly is in the first position and compressed when the slider assembly is in the second position, driving the slider assembly distally from the second position back to the first position. The auto-injector also includes a pair of connecting rods that connect the syringe housing to the injector body, the pair of connecting rods being pivotable relative to the syringe housing and the injector body respectively, and the pair of connecting rods interact with a slider assembly so that when the injector body is pivoted to the open position, a spring is compressed.

[0007] In a particular configuration, the slider housing defines a central channel therein for receiving a guide pin and a spring, and the proximal end of the central channel includes a spring retaining member configured to hold the spring within the central channel and a deflectable hook structure configured to interact with the slide assembly.

[0008] In a particular configuration, the slider assembly includes a distal end and a proximal end, a guide pin extending between the distal and proximal ends, and the slider assembly further includes a cylindrical end member located at the distal end of the slider assembly, the cylindrical member having a closed bottom surface defining a chamber therein, the guide pin extending proximal from the closed bottom surface, through the chamber to the proximal end of the slider assembly, and comprising a stepped portion extending radially outward from the cylindrical end member on the upper surface of the cylindrical end member, and a tongue structure formed on the guide pin adjacent to the proximal end of the slider assembly, the tongue structure being configured to engage with a deflectable hook structure when the slider assembly moves to a second position, locking the slider assembly in the second position and locking the spring in a compressed state.

[0009] In certain configurations, the distal end of the spring is positioned within a chamber of a cylindrical end member, which holds the spring in place and allows for spring compression when the slider assembly is moved from a first position to a second position.

[0010] In a particular configuration, the slider housing includes an inner surface having a pair of axial channels formed therein, the pair of axial channels being located on opposite sides of the slider housing, and the injector body further includes rollers positioned in each of the pair of axial channels so as to be axially movable along the pair of axial channels, and each connecting rod of the pair of connecting rods is pivotably connected to each roller so as to axially translate the rollers along the pair of axial channels.

[0011] In certain configurations, the rollers contact a step in the slider assembly such that the axial translation of the rollers by a pair of connecting rods causes the slider assembly to move axially within the slider housing.

[0012] In certain configurations, when the slider assembly is moved to a second position, the tongue structure engages with a deflectable hook structure, thereby locking the slider assembly in the second position, and the spring locks in a compressed state as the injector body rotates from the open to the closed position.

[0013] In certain configurations, the injector body further comprises a trigger cap located at the proximal end of the slider housing, which, when pressed down, interacts with the slider assembly to disengage a tongue structure from a deflectable hook structure, thereby unlocking the slider assembly and spring, allowing the spring to transition from a compressed state to an extended state and move the slider assembly from a second position to a first position.

[0014] In certain configurations, the internal carrier includes an elongated channel formed within the syringe housing, with the proximal opening of the channel exposed when the injector body is in the open position, allowing a pre-filled syringe to be loaded into the channel.

[0015] In certain configurations, when the injector body is in the closed position, the closed bottom surface of the cylindrical end member abuts against the proximal end of the plunger rod of a pre-filled syringe when loaded into the syringe housing.

[0016] In a particular configuration, the auto-injector further comprises a syringe housing spring positioned within an elongated channel and configured to surround the barrel of a pre-filled 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 between them, wherein the needle cover is movable 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 protrudes through the opening at the distal end of the needle cover, and a post-use position in which the needle cover surrounds the needle.

[0017] In certain configurations, when transitioning from a compressed to an extended state, the spring generates enough force to allow the needle of a pre-filled syringe to penetrate the patient's skin surface and dispense the medication contained within the syringe.

[0018] In certain configurations, when in the second position, the injector body is rotated by more than 90 degrees relative to the syringe housing.

[0019] In certain configurations, a pair of connecting rods are connected to the syringe housing on the outer surface of the syringe housing via a pair of rod pivot pins.

[0020] In a particular configuration, the slider housing includes a seat formed within its internal volume, and the slider assembly further includes a pair of retaining arms connected to a step and extending proximal therefrom, each of which includes a hooked proximal end that engages with the seat when the slider assembly is in a first position, thereby preventing further distal movement.

[0021] In certain configurations, a pair of connecting rods convert the rotational motion of the injector body into the linear motion of the slider assembly.

[0022] Furthermore, this specification also provides drug delivery devices including an auto-injector and a pre-filled syringe. The pre-filled syringe is at least partially received within an internal carrier of a syringe housing and includes a syringe barrel having a proximal end, a distal end, and side walls defining the interior containing a drug; a needle located at the distal end of the syringe barrel and in fluid communication with the interior of the syringe; and a plunger assembly movable within the interior of the syringe and comprising a plunger rod and a stopper, the stopper located at the distal end of the plunger rod.

[0023] In a particular configuration, the proximal end of the plunger rod extends proximally beyond the syringe housing when the pre-filled syringe is at least partially received within the internal carrier of the syringe housing and extends into the slider housing when the injector body is in the closed position.

[0024] In a particular configuration, when the injector 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 against the proximal end of the plunger rod.

[0025] In a particular configuration, when the trigger cap is pushed down, thereby causing the spring to transition from the compressed state to the extended state and enabling 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 syringe, causing injection of the drug.

Brief Description of the Drawings

[0026] [Figure 1A] FIG. 1A is a front view of a drug delivery device in an initial closed position, according to a non-limiting embodiment described herein. [Figure 1B] FIG. 1B is a front view of the drug delivery device of FIG. 1A in the closed position. [Figure 1C] FIG. 1C is a front view of the drug delivery device of FIG. 1A in the closed injection position. [Figure 2A] FIG. 2A is a front cross-sectional view of the drug delivery device of FIG. 1A. [Figure 2B] FIG. 2B is a side cross-sectional view of the drug delivery device of FIG. 1A. [Figure 3] FIG. 3 is a front cross-sectional view of the drug delivery device of FIG. 1B. [Figure 4A] FIG. 4A is a front cross-sectional view of the drug delivery device of FIG. 1C in the pre-injection position. [Figure 4B] FIG. 4B is a side cross-sectional view of the drug delivery device of FIG. 1C in the pre-injection position. [Figure 5A]Figure 5A is a front cross-sectional view of the drug delivery device shown in Figure 1C, in the post-injection position. [Figure 5B] Figure 5B is a side cross-sectional view of the drug delivery device shown in Figure 1C, in the post-injection position. [Modes for carrying out the invention]

[0027] The following description is provided to enable those skilled in the art to manufacture and use the described embodiments intended for carrying out the invention. However, various modifications, equivalents, variations, and substitutes will be readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and substitutes are intended to fall within the spirit and scope of the invention.

[0028] Hereafter, for explanatory purposes, the terms “upper,” “lower,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “lateral,” “longitudinal,” and their derivatives are used in relation to the present invention as oriented in the drawings. However, it will be understood that the present invention may presuppose various alternative modifications unless expressly otherwise specified. It should also be understood that the specific devices shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the present invention. Accordingly, specific dimensions and other physical characteristics relating to the embodiments disclosed herein should not be construed as limiting.

[0029] As used herein, the terms “proximal” and “distal” refer to the directions closer to and farther from the user who will bring the device into contact with other components or a patient, respectively. Therefore, for example, the end of the device that first comes into contact with other components or the patient's body is the distal end, and the opposite end of the device being operated by the user is the proximal end of the device.

[0030] The terms “first,” “second,” and similar terms are not intended to refer to any particular order or time sequence, but rather to different conditions, characteristics, or elements.

[0031] Referring to Figures 1A to 1C, a drug delivery device 10 is shown, which includes an auto-injector 12 and a pre-filled syringe 14 that can be loaded into the auto-injector 12 for administering a drug to a patient. The auto-injector 12 generally includes a syringe housing 16 for receiving the pre-filled syringe 14, an injector body 18 that interacts with the syringe housing 16 and the pre-filled syringe 14 to facilitate the injection of the drug, and a pair of connecting rods 20 that connect the syringe housing 16 to the injector body 18, the pair of connecting rods 20 which may be characterized to function to allow a pivoting spring load of the injector body 18 when the injector body 18 rotates relative to the syringe housing 16. During operation, the auto-injector 12 can pivot from an initial closed position (Figure 1) where the injector body 18 is aligned with the syringe housing 16 to an open position (Figure 1A) where the injector body 18 is rotated relative to the syringe housing 16, and can be returned to a closed position (Figure 1C) to provide execution of injection (i.e., a closed injection position).

[0032] Referring here to Figures 2 to 5, front and side cross-sectional views of the drug delivery device 10 are shown during various stages of the device's operation, including the initial closed position (Figures 2A and 2B), the open position (Figure 3), the loaded closed position (Figures 4A and 4B), and the ejected / unloaded closed position (Figures 5A and 5B).

[0033] As shown in Figures 2-6, the syringe housing 16 is provided 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, defining an internal carrier 28 into which a pre-filled syringe 14 can be loaded, and the internal carrier 28 defines an elongated channel 30 within the syringe housing 16. As best shown in Figure 3, the pre-filled syringe 14 includes a barrel 32 having a proximal end 34 and a distal end 36, defining an interior 38 configured to hold one or more drugs therein. The 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, allowing one or more drugs to be discharged through the needle 40. The stopper 42 may be moved by a plunger rod 44 under the influence of the injector body 18, as will be described in more detail below. The plunger rod 44 has a proximal end 46 that can be actuated by the injector body 18 and a distal end 48 configured to engage with the stopper 42.

[0034] When loading a pre-filled syringe 14 into the syringe housing 16, the injector body 18 can be rotated to the open position to expose the proximal opening 50 of the elongated channel 30, allowing the pre-filled syringe 14 to be loaded into the elongated channel 30. With the channel 30 of the internal carrier 28 exposed, the barrel 32 is positioned within the internal carrier 28. The pre-filled syringe 14 is received within the internal carrier 28 such that the plunger rod 44 extends beyond the proximal end 24 of the syringe housing 16, thereby providing interaction between the injector body 18 and the syringe 14.

[0035] According to embodiments of this disclosure, a movable needle cover 52 may be provided at the distal end 26 of the syringe housing 16. The needle cover 52 may include a tubular distal portion 54 configured to surround the needle 40 and one or more arms 56 extending proximal from the tubular portion 54. The needle cover 52 may be retractable relative to the syringe housing 16 and may move from a pre-use position where the needle cover 52 extends a first distance beyond the distal end 26 of the syringe housing 16 and surrounds the needle 40 of the syringe 14, to a use position where the needle cover 52 moves proximal to expose the needle 40, and further to a post-use position where the needle cover 52 extends a second distance beyond the distal end 26 of the syringe housing 16 and surrounds 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 re-exposed.

[0036] According to aspects of the present disclosure, the injector body 18 includes a slider housing 60 having a proximal end 62 and a distal end 64; a slider assembly 66 disposed within the slider housing 60 and movable axially relative to the slider housing 60; a roller 68 that engages with the slider assembly 66 and the slider housing 60; and a trigger cap 70 disposed at the proximal end 62 of the slider housing 60 and configured to interact with the slider assembly 66 when pressed down.

[0037] The distal end 64 of the slider housing 60 connects the slider housing 60 to the syringe housing 16 and is pivotally connected to the proximal end 24 of the syringe housing 16 via a pivot member 72, such as a pivot pin, which rotates the slider housing 60 relative to the syringe housing 16. The pivot member 72 allows the slider housing 60 (and the entire injector body 18) to rotate relative to the syringe housing 16, providing rotation between a closed position where the injector body 18 is aligned with the syringe housing 16 and an open position where the injector body 18 is rotated relative to the syringe housing 16, thereby providing access to the internal carrier 28 of the syringe housing 16 and allowing insertion of a pre-filled syringe 14 therein. In some embodiments, the slider housing 60 (and the entire injector body 18) may rotate more than 90 degrees relative to the syringe housing 16 when in the open position.

[0038] The slider housing 60 includes an inner surface 74 having several features that interact with other components of the injector body 18. The inner surface 74 of the slider housing 60 may include a pair of axial channels 76 formed inward on opposing sides of the slider housing 60, in which rollers 68 can be translated during the operation of the auto-injector 12. The slider housing 60 may also include a seat 78 formed on it that restricts the movement of the slider assembly 66 within the slider housing 60. The inner surface 74 of the slider housing 60 also defines a central channel 80 in which a portion of the slider assembly 66 can move relative to the slider housing 60, and the proximal end of the central channel 80 includes a spring retaining member 82 and a deflectable hook structure 84 configured to interact with the slider assembly 66, as will be described in more detail below.

[0039] The slider assembly 66 of the injector body 18 is located within the slider housing 60, extending longitudinally therein, with the distal end 86 of the slider assembly 66 positioned near the distal end 64 of the slider housing 60, and the proximal end 87 of the slider assembly 66 positioned 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.

[0040] In exemplary embodiments, the guide pin 88, cylindrical end member 92, step 94, and retaining arm 96 are formed as a single, integrated member, which may include, for example, a molded part. The cylindrical end member 92 is located at the distal end 86 of the slider assembly 66 and has a closed bottom surface 98 in which a chamber 100 is defined, and the chamber 100 receives a portion of the spring 90. The guide pin 88 extends proximal outward 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 upper surface of the cylindrical end member 92, and a pair of retaining arms 96 are connected to the step 94 and extend proximal therefrom. Each of the retaining arms 96 includes a hooked proximal end 101 that engages with a seat 78 of the slider housing 60 when the slider assembly 66 is in a first position, preventing further distal movement of the slider assembly 66. Further details will be described later.

[0041] A guide pin 88 of the slider assembly 66 extends between the distal end 86 and the proximal end 87 of the slider assembly 66, allowing the slider assembly 66 to move axially relative to the slider housing 60 between a first position (Figures 2A and 2B and 5A and 5B) and a second position (Figures 3 and 4A and 4B), where the second position is distal to the first position and is configured to guide the movement of the slider assembly 66 within the slider housing 60. A spring 90 is positioned on the guide pin 88 and is actuated between an extended state (Figures 2A and 2B and 5A and 5B) and a compressed state (Figures 3 and 4A and 4B), and a spring retaining member 82 functions as a stopper to hold the spring 90 in place. During the operation of the auto-injector 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 a second position to a first position when transitioning from a compressed state to an extended state. The tongue structure 102 is formed on a guide pin 88 adjacent to the proximal end 87 of the slider assembly 66 and is configured to engage with a deflectable hook structure 84 of the slider housing 60 when the slider assembly 66 is moved to the second position. That is, when the slider assembly 66 is moved to the second position, the tongue structure 102 is positioned proximal to the hook structure 84 and supported by the back / proximal surface of the hook structure 84, locking the slider assembly 66 in the second position and maintaining the spring 90 in a compressed state when the injector body 18 is rotated from an open position to a closed position. According to the embodiment, the tongue structure 102 may be configured as a disk-shaped projection extending radially from the guide pin 88, and the back / proximal surface of the hook structure 84 may have a horizontal surface that holds the disk-shaped projection, however, it is recognized that the tongue structure 102 and / or the hook structure 84 may have other suitable shapes.

[0042] The rollers 68 of the injector body 18 are arranged within a pair of axial channels 76 formed in the slider housing 60, with each roller 68 positioned within each of the axial channels 76. The rollers 68 are configured to move axially along the axial channels 76. The movement of the rollers 68 is achieved by rotating the connecting rods 20 as the injector body 18 is rotated relative to the syringe housing 16, such that each connecting rod 20 is pivotally connected to the syringe housing 16 at a first end (e.g., on the outer surface of the syringe housing 16, via a pair of rod pivot pins 106, for example) and pivotally connected to each roller 68 at a second end (e.g., having a circular end positioned around a portion of the roller 68). Thus, the assembly of the connecting rod 20 and the roller 68 effectively operates as a slider-crank mechanism, where the rotation of the connecting rod 20 (i.e., the "crank") is converted into the linear motion of the roller 68 (i.e., the "slider") within the slider housing 60 along a pair of axial channels 76. The roller 68 is positioned within the channels 76 so as to be distal to the step 94 of the slider assembly 66, and the roller 68 contacts the step 94 as the auto-injector 12 transitions from an initial closed state to an open state, and as a result the roller 68 moves axially in the proximal direction, the slider assembly 66 also moves proximal within the slider housing 60. More specifically, when the auto-injector 12 moves from its initial closed state to an open state (in response to the rotation of the injector body 18 relative to the syringe housing 16), the connecting rod 20 is rotated, and the rotation of the connecting rod 20 moves the roller 68 proximal within the channel 76, which in turn presses the slider assembly 66 and moves it proximal within the slider housing 60.

[0043] As described above, the trigger cap 70 is located at the proximal end 62 of the slider housing 60 and is accessible at the proximal end of the injector body 18 so that it can be pressed down by the user. The trigger cap 70 extends into the slider housing 60 so that it can interact with the slider assembly 66 when pressed down. That is, when the trigger cap 70 is pressed down, the trigger cap 70 moves the deflectable hook structure 84 radially outward, and the radially outward movement of the hook structure 84 releases the tongue structure 102 from its proximal position to the hook structure 84 (i.e., releases the tongue structure 102 from the back / proximal surface of the hook structure 84). When the tongue structure 102 is released, the slider assembly 66 is unlocked, and the spring 90 can move from its compressed state to its extended state, thereby returning the slider assembly 66 from the second position to the first position, pushing the needle 40 of the pre-filled syringe 14 into the patient, and the plunger rod 44 is further pushed into the barrel 32 to dispense the medication.

[0044] The operation of the drug delivery device 10 will be described with reference to the drawings. The reusable auto-injector 12 is provided in an initial closed position (Figures 1A and 2A and 2B), with the injector body 18 aligned with the syringe housing 16. The user can then grasp the auto-injector 12 and pivot the injector body 18 relative to the syringe housing 16 to move the auto-injector 12 from the initial closed position to the open position (Figures 1B and 3). When pivoting to the open position, the injector body 18 pivots around a pivot pin 72 that connects the slider housing 60 to the syringe housing 16. When the auto-injector 12 is in the open position, that is, when the injector body 18 is rotated by 90 degrees or more relative to the syringe housing 16, the pre-filled syringe 14 is inserted into the syringe housing 16 and fixed within the internal carrier 28 of the syringe housing 16, with the proximal end of the syringe (i.e., the plunger rod 44) ​​protruding beyond the proximal end 24 of the syringe housing 16.

[0045] When the auto-injector 12 is moved from its initial closed position to the open position, the connecting rod 20 of the auto-injector 12 rotates in relation to the injector body 18. The rotation of the connecting rod 20 causes the associated linear motion of a roller 68 located within the slider housing 60 of the injector body 18, and the connecting rod 20 and the roller 68 thus function as a slider-crank mechanism within the auto-injector 12. When the injector body 18 rotates to its open position, the roller 68 is moved proximal within the axial channel 76 of the slider housing 60, and this proximal movement of the roller 68 within the slider housing 60 also pushes and moves the slider assembly 66 proximal within the slider housing 60. That is, the roller 68 contacts a step 94 of the slider assembly 66 so that the axial movement of the roller 68 proximal causes the slider assembly 66 to move proximal within the slider housing 60. Therefore, when the injector body 18 rotates to its open position, the slider assembly 66 moves proximal to the second position (Figure 3) from the first position (Figures 2A and 2B).

[0046] As the slider assembly 66 moves to its second position, the guide pin 88 moves 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 moves proximal to the side, so that the slider assembly 66 is locked in the second position. That is, when the slider assembly 66 is moved to the second position, the tongue structure 102 is positioned proximal to the hook structure 84 and is in contact with the back / proximal surface of the hook structure 84, locking the slider assembly 66 in the second position and maintaining the spring 90 in a compressed state as the injector body 18 rotates from the open position to the closed position.

[0047] Furthermore, as the slider assembly 66 moves to its second position, the spring 90 positioned around 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 (above the proximal end of the spring 90) and the closed bottom surface 98 of the cylindrical end member 92 (above the distal end of the spring 90), with the distal end of the spring 90 held within the chamber 100 of the cylindrical end member 92, and the movement of the slider assembly 66 to the second position compresses the spring 90. When the slider assembly 66 reaches the second position, the slider assembly 66 is locked in the second position due to the interaction between the tongue structure 102 and the deflectable hook structure 84, and the spring 90 is also locked in its compressed state.

[0048] Once the slider assembly 66 is locked in the second position and its spring 90 is "loaded" into its compressed state, the injector body 18 can be rotated backward from the open position to the closed position (i.e., the closed injection position, Figures 1C and 4A and 4B). When the injector body 18 rotates back to the closed injection position, the slider assembly 66 is held in the second position due to the interaction / locking of the tongue structure 102 and the hook structure 84, and therefore the spring 90 also maintains its compressed state. When the injector body 18 rotates 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 may be in direct contact with the proximal end of the plunger rod 44.

[0049] If it is desirable for the drug delivery device 10 to perform an injection, the user may press down the trigger cap 70 of the auto-injector 12. When the trigger cap 70 is pressed, it moves the deflectable hook structure 84 radially outward, and the radially outward movement of the hook structure 84 releases the tongue structure 102 from its proximal position to the hook structure 84, so that the slider assembly 66 is 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 returns from the second position to the first position (Figures 5A and 5B), and the hook-shaped proximal ends 101 on each of the retaining arms 96 engage with the seat 78 of the slider housing 60, stopping the movement of the slider assembly 66 in the first position.

[0050] As it retracts toward the first position, the closed bottom surface 98 of the cylindrical end member 92 (of the slider assembly 66) applies a pushing force against the proximal end of the pre-filled syringe 14, i.e., 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 first penetrate the needle 40 of the pre-filled syringe 14 into the patient's skin surface, and then to push the plunger rod 44 further distally into the syringe barrel 32, thereby dispensing the medication from the pre-filled syringe 14.

[0051] Beneficially, embodiments of the present disclosure thus provide a reusable auto-injector for drug delivery. The auto-injector includes a pivotable structure that automatically loads / compresses the auto-injector's spring when the auto-injector rotates and opens to introduce a pre-filled syringe into it. Thus, the rotation of the auto-injector (for syringe introduction) and spring compression are integrated into a single step, reducing the number of steps required for the assembly and use of the auto-injector, thereby improving the user experience of the device.

[0052] The present invention has been described in detail for illustrative purposes based on what is currently considered to be the most practical and preferred embodiments or aspects, but such details are for that purpose only, and it should be understood that the present invention is not limited to the disclosed embodiments or aspects, but rather intended to encompass modifications and equivalent arrangements that fall within the spirit and scope of the appended claims. For example, it should be understood that, wherever possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

1. A reusable auto-injector for drug delivery, The aforementioned auto-injector is A syringe housing having a proximal and distal end, defining an internal carrier configured to receive a pre-filled syringe, An injector body pivotably connected to the syringe housing, wherein the injector body is pivotable between a closed position in which it is aligned with the syringe housing and an open position in which it is rotated relative to the syringe housing, The injector body is, A slider housing having a proximal end and a distal end, wherein the distal end of the slider housing is pivotably connected to the proximal end of the syringe housing via a pivot member, A slider assembly disposed within the slider housing and movable axially between a first position and a second position relative to the slider housing, wherein the slider assembly includes guide pins configured to guide the movement of the slider assembly within the slider housing, A spring disposed on the guide pin and operable 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, the spring is in the compressed state when the slider assembly is in the second position, and when transitioning from the compressed state to the extended state, the spring drives the slider assembly distally from the second position to the first position. The injector body, A pair of connecting rods that connect the syringe housing to the injector body, wherein the pair of connecting rods are pivotable relative to the syringe housing and the injector body, respectively, and the pair of connecting rods interact with the slider assembly and act to compress the injector body when the spring pivots the injector body to the open position, An auto-injector equipped with this feature.

2. The slider housing defines a central channel inside for receiving the guide pin and the spring, The proximal end of the central channel is A spring retaining member configured to hold the spring within the central channel, A deflectable hook structure configured to interact with the slider assembly, The auto injector according to claim 1, including the following:

3. The slider assembly includes a distal end and a proximal end, and the guide pin extends between the distal end and the proximal end. The aforementioned slider assembly is A cylindrical end member positioned at the distal end of the slider assembly, wherein the cylindrical end member has a closed bottom surface defining a chamber inside, and the guide pin extends proximal from the closed bottom surface, through the chamber, to the proximal end of the slider assembly, A step extending radially outward from the cylindrical end member on the upper surface of the cylindrical end member, A tongue structure formed on the guide pin adjacent to the proximal end of the slider assembly, wherein the tongue structure is configured to engage with the deflectable hook structure when the slider assembly is moved to the second position, locking the slider assembly in the second position and locking the spring in the compressed state, The auto injector according to claim 2, comprising:

4. The auto injector according to claim 3, wherein the distal end of the spring is positioned within the chamber of the cylindrical end member, and holds the spring in a predetermined position and allows the spring to be compressed when the slider assembly is moved from a first position to a second position.

5. The auto injector 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 located on opposite sides of the slider housing, and the injector body further includes rollers positioned in each of the pair of axial channels so as to be axially movable along the pair of axial channels, each connecting rod of the pair of connecting rods being pivotably connected to each roller, and the pair of connecting rods moving the rollers axially along the pair of axial channels.

6. The auto injector according to claim 5, wherein the roller contacts the step of the slider assembly such that the axial movement of the roller by the pair of connecting rods causes the slider assembly to move axially within the slider housing.

7. The auto injector according to claim 3, wherein when the slider assembly is moved to the second position, the tongue structure engages with the deflectable hook structure, locking the slider assembly in the second position, and when the injector body is rotated from the open position to the closed position, the spring locks in the compressed state.

8. The auto-injector according to claim 3, wherein the injector body further comprises a trigger cap located at the proximal end of the slider housing, the trigger cap interacting with the slider assembly when pressed down, disengaging the tongue structure from the deflectable hook structure, thereby unlocking the slider assembly and the spring, allowing the spring to transition from the compressed state to the extended state, and moving the slider assembly from the second position to the first position.

9. The auto-injector according to claim 3, wherein the syringe housing includes an internal carrier defining an elongated channel within the syringe housing, and when the injector body is in the open position, the proximal opening of the elongated channel is exposed, allowing a pre-filled syringe to be loaded into the elongated channel.

10. The auto-injector according to claim 9, wherein, when the injector body is in the closed position, the closed bottom surface of the cylindrical end member abuts against the proximal end of the plunger rod of the pre-filled syringe when loaded into the syringe housing.

11. A syringe housing spring is disposed within the elongated channel and configured to surround the barrel of the pre-filled syringe when inserted into the elongated channel. A needle cover having a proximal end, a distal end including an opening, and a side wall between them, wherein the needle cover is movable by a spring of the syringe housing between a pre-use position in which the needle cover surrounds the needle, a use position in which the needle protrudes through the opening at the distal end of the needle cover, and a post-use position in which the needle cover surrounds the needle. The auto injector according to claim 9, further comprising:

12. The auto-injector according to claim 1, wherein when transitioning from the compressed state to the extended state, the spring generates sufficient force to penetrate the needle of the pre-filled syringe into the patient's skin surface and to dispense the drug contained in the pre-filled syringe.

13. The auto-injector according to claim 1, wherein when in the second position, the injector body is rotated by 90 degrees or more relative to the syringe housing.

14. The auto-injector according to claim 1, wherein the pair of connecting rods are connected to the syringe housing on the outer surface of the syringe housing via a pair of rod pivot pins.

15. The auto injector according to claim 1, wherein the slider housing includes a seat formed within its internal volume, and the slider assembly further includes a pair of retaining arms connected to the step and extending proximal therefrom, each of the pair of retaining arms including a hook-shaped proximal end that engages with the seat when the slider assembly is in the first position, thereby preventing further distal movement.

16. The auto injector according to claim 1, wherein the pair of connecting rods convert the rotational motion of the injector body into the linear motion of the slider assembly.

17. It is an auto-injector, A syringe housing having a proximal and distal end, defining an internal carrier configured to receive a pre-filled syringe, An injector body pivotably connected to the syringe housing, wherein the injector body is pivotable between a closed position in which it is aligned with the syringe housing and an open position in which it is rotated relative to the syringe housing, The injector body is, A slider housing having a proximal end and a distal end, wherein the distal end of the slider housing is pivotably connected to the proximal end of the syringe housing via a pivot member, A slider assembly disposed within the slider housing and movable axially between a first position and a second position relative to the slider housing, wherein the slider assembly includes guide pins configured to guide the movement of the slider assembly within the slider housing, A spring disposed on the guide pin and operable 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, the spring is in the compressed state when the slider assembly is in the second position, and when transitioning from the compressed state to the extended state, the spring drives the slider assembly distally from the second position to the first position. The injector body includes, A pair of connecting rods that connect the syringe housing to the injector body, wherein the pair of connecting rods are pivotable relative to the syringe housing and the injector body, respectively, the pair of connecting rods interact with the slider assembly, and the spring acts to compress the injector body when the injector body is pivoted to the open position, An auto injector equipped with, A pre-filled syringe, at least partially housed within the internal carrier of the syringe housing, The aforementioned pre-filled syringe is A syringe barrel including a proximal end, a distal end, and side walls defining the interior containing the drug, A needle is positioned at the distal end of the syringe barrel and is in fluid communication with the inside of the syringe, A plunger assembly is provided, which is movable within the syringe and includes a plunger rod and a stopper, the stopper being positioned at the distal end of the plunger rod. A pre-filled syringe equipped with, Drug delivery devices, including those mentioned above.

18. The drug delivery device according to claim 17, wherein the proximal end of the plunger rod extends proximal through the syringe housing when the pre-filled syringe is at least partially received in the internal carrier of the syringe housing, and the injector body extends into the slider housing when the injector body is in the closed position.

19. The drug delivery device according to claim 18, wherein, with the injector 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 against the proximal end of the plunger rod.

20. The drug delivery device according to claim 19, wherein when the trigger cap is pressed down, thereby causing the spring to move from the compressed state to the extended state and enabling 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 syringe, causing the injection of the drug.

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