Reusable auto-injection device with pivoting spring load

Abstract

A reusable auto-injector is provided including 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 positioned within the slider housing and movable axially relative thereto between first and second positions. The slider assembly includes a guide pin with a spring positioned thereon that is actuatable between an extended state and a compressed state. The spring is in the extended state with the slider assembly in the first position and is in the compressed state with the slider assembly 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 upon pivoting of the injector body to the open position.

Description

REUSABLE AUTO-INJECTION DEVICE WITH PIVOTING SPRING LOADCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Chinese Application No. 202310860887.0 entitled “Reusable Auto-Injection Device with Pivoting Spring Load” filed July 13, 2023, the disclosure of which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTIONField of the Invention

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

[0003] Drug delivery devices, such as auto-injection devices (i.e., “auto-injectors”), are used to administer a medicament to a patient. Some types of auto-injectors are designed as disposable or single use devices that may only be used to deliver one dose of medication, with the injector then being disposed after use. Other types of auto-injectors are designed as reusable injectors, with such reusable injectors typically being designed to allow a user to load and unload a standard pre-filled syringe thereto.

[0004] While effective in delivering a medicament to a patient, current reusable autoinjectors often have a complex design that makes use of the auto-injector difficult. For example, current reusable auto-injectors typically include a separate syringe housing and injector body that require an initial separation step, with a patient then required to performs separate steps of (1) “energizing” the injector body by compressing a feature thereon, (2) inserting the syringe into the syringe housing, and (3) re-assembling the syringe housing and injector body (e.g., screwing the components together). This multi-step process of preparing the auto-injector is thus recognized as being complicated and not user-friendly for patients’ daily use.

[0005] Accordingly, there is a need in the art for reusable drug delivery devices, such as reusable auto -injectors, having a simplified design that reduces the number of steps required for assembly and use of the auto-injector, thereby improving the user experience with the device.SUMMARY OF THE INVENTION

[0006] Provided herein is a reusable auto-injector for drug delivery. The auto-injector includes a syringe housing having a proximal end and a distal end and defining an interior carrier configured to receive a pre-filled syringe therein, and an injector body pivotably connected to the syringe housing, the injector body pivotable between a closed position where the injector body is aligned with the syringe housing and an open position where 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 pivotably coupled to the proximal end of the syringe housing via a pivot member, a slider assembly positioned 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 movement of the slider assembly within the slider housing, and a spring positioned on the guide pin and actuatable between an extended state and a compressed state, with the spring in the extended state with the slider assembly in the first position and in the compressed state with the slider assembly in the second position, and wherein the spring drives the slider assembly distally from the second position back to the first position when transitioning from the compressed state to the extended state. The auto-injector also includes a pair of connecting rods connecting the syringe housing to the injector body, with the pair of connection rods pivotable relative to each of the syringe housing and the injector body, wherein the pair of connecting rods interact with the slider assembly such that the spring is actuated to the compressed state upon pivoting of the injector body to the open position.

[0007] In certain configurations, the slider housing defines a central channel therein that receives the guide pin and the spring, and wherein a proximal end of the central channel includes a spring retention member thereon configured to retain the spring within the central channel and a deflectable hook structure configured to interact with the slide assembly.

[0008] In certain configurations, the slider assembly includes a distal end and a proximal end, with the guide pin extending between the distal end and the proximal, and wherein the slider assembly further comprises a cylindrical end member positioned at the distal end of the slider assembly, the cylindrical member having a closed bottom surface and defining a chamber therein, with the guide pin extending proximally out from the closed bottom surface and through the chamber 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 formed on the guide pin adjacent the proximal end of the slider assembly, the tongue structure configured to engage with the deflectable hook structure when the sliderassembly is moved to the second position, to lock the slider assembly in the second position and the spring in the compressed state.

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

[0010] In certain configurations, the slider housing comprises an interior surface having a pair of axial channels formed therein, the pair of axial channels positioned on opposing sides of the slider housing, and wherein the injector body further comprises a roller positioned in each of the pair of axial channels so as to be movable axially along the axial channels, with a respective connecting rod of the pair of connecting rods pivotably connected to each roller, such that the pair of connecting rods cause the rollers to translate axially along the pair of axial channels.

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

[0012] In certain configurations, the tongue structure engages with the deflectable hook structure when the slider assembly is moved to the second position, such that the slider assembly is locked in the second position and the spring is locked in the compressed state when the injector body is rotated from the open position to the closed position.

[0013] In certain configurations, the injector 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, 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 the compressed state to the extended state and cause the slider assembly to move from the second position to the first position.

[0014] In certain configurations, the interior carrier comprises an elongated channel formed within the syringe housing, and wherein a proximal opening of the elongated channel is exposed when the injector body is in the open position, so as to enable loading of a pre-filled syringe into the elongated channel.

[0015] In certain configurations, with the injector body in the closed position, the closed bottom surface of the cylindrical end member abuts a proximal end of a plunger rod of the prefilled syringe, when loaded in the syringe housing.

[0016] In certain configurations, the auto-injector further comprises a syringe housing spring positioned within the elongated channel and configured to encircle a barrel of the pre-filledsyringe when inserted into the elongated channel, and a needle cover having a proximal end, a distal end comprising an opening, and a sidewall therebetween, the needle cover 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 protrudes through the opening in 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 the compressed state to the extended state, the spring generates a force sufficient to cause a needle of the pre-filled syringe to pierce the dermal surface of a patient and cause a medicament within the pre-filled syringe to dispense.

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

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

[0020] In certain configurations, the slider housing comprises a seat formed within an interior volume thereof, and wherein the slider assembly further comprises a pair of retaining arms connected to the step and extending out proximally therefrom, each of the pair of retaining arms including a hooked proximal end that engages the seat to when the slider assembly is at the first position, so as to prevent further distal travel.

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

[0022] Also provided herein is a drug delivery device that includes an auto-injector and a pre-filled syringe. The pre-filled syringe is received at least partially within the interior carrier of the syringe housing, and the pre-filled syringe includes a syringe barrel including a proximal end, a distal end, and a sidewall defining an interior containing a medicament, a needle arranged at the distal end of the syringe barrel and in fluid communication with the syringe interior, and a plunger assembly movable within the syringe interior and comprising a plunger rod and a stopper, the stopper arranged at a distal end of the plunger rod.

[0023] In certain configurations, a proximal end of the plunger rod extends out proximally past the syringe housing when the pre-filled syringe is received at least partially within the interior carrier of the syringe housing, so as to extend into the slider housing when the injector body is in the closed position.

[0024] In certain configurations, 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 the proximal end of the plunger rod.

[0025] In certain configurations, upon the trigger cap being depressed and thereby 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, the closed bottom surface of the cylindrical end member distally advances the plunger rod into the syringe interior, so as to cause injection of the medicament.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1A is a front view of a drug delivery device in an initial closed position, according to a non-limiting embodiment described herein;

[0027] FIG. IB is a front view of the drug delivery device of FIG. 1A in an open position;

[0028] FIG. 1C is a front view of the drug delivery device of FIG. 1A in a closed injection position;

[0029] FIG. 2A is a front cross-sectional view of the drug delivery device of FIG. 1 A;

[0030] FIG. 2B is a side cross-sectional view of the drug delivery device of FIG. 1 A;

[0031] FIG. 3 is a front cross-sectional view of the drug delivery device of FIG. IB;

[0032] FIG. 4A is a front cross-sectional view of the drug delivery device of FIG. 1C, in a pre-injection position;

[0033] FIG. 4B is a side cross-sectional view of the drug delivery device of FIG. 1C, in a pre-injection position;

[0034] FIG. 5A is a front cross-sectional view of the drug delivery device of FIG. 1C, in a post-injection position; and

[0035] FIG. 5B is a side cross-sectional view of the drug delivery device of FIG. 1C, in a post-injection position.DESCRIPTION OF THE INVENTION

[0036] The following description is provided to enable those skilled in the art to make and use the described embodiments contemplated for carrying out the invention. Various modifications, equivalents, variations, and alternatives, however, will remain readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and alternatives are intended to fall within the spirit and scope of the present invention.

[0037] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal", and derivatives thereof shall relate to the invention as it is oriented in the drawing figures. However, it is to be understood that the invention may assume various alternative variations, except where expressly specifiedto the contrary. It is also to be understood that the specific devices illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered as limiting.

[0038] As used in this specification, the words “proximal” and “distal” refer to the direction closer to and away from, respectively, a user who would place the device into contact with another component or with a patient. Thus, for example, the end of a device first contacting another component or the body of the patient would be the distal end, while the opposite end of the device being manipulated by the user would be the proximal end of the device.

[0039] The terms “first”, “second”, and the like are not intended to refer to any particular order or chronology, but refer to different conditions, properties, or elements.

[0040] Turning to FIGS. 1A-1C, shown is a drug delivery device 10 that includes an autoinjector 12 and a pre-filled syringe 14 that may be loaded into the auto-injector 12 for administering a medicament to a patient. The auto-injector 12 may be characterized as generally including 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 injection of the medicament, and a pair of connection rods 20 that couple the syringe housing 16 to the injector body 18, with the pair of connection rods 20 functioning to enable a pivoting spring loading of the injector body 18 upon rotation of the injector body 18 relative to the syringe housing 16, as described in further detail below. In operation, the auto-injector 12 may be pivoted from an initial closed position (FIG. 1) where the injector body 18 is aligned with the syringe housing 16, to an open position (FIG. 1A) where the injector body 18 is rotated relative to the syringe housing 16, and back to the closed position (FIG. 1C) to provide for performing of an injection (i.e., a closed injection position).

[0041] Referring now to FIGS. 2-5, front and side cross-sectional views of the drug delivery device 10 are shown during various stages of operation of the device, including in an initial closed position (FIGS. 2A and 2B), in an open position (FIG. 3), in a loaded closed position (FIGS. 4A and 4B), and in a discharged / unloaded closed position (FIGS. 5A and 5B).

[0042] As shown in FIGS. 2-6, syringe housing 16 is provided at a distal end 22 of drug delivery device 10. The syringe housing 16 has a proximal end 24 and a distal end 26 and defines an interior carrier 28 within which a pre-filled syringe 14 may be loaded, with the interior carrier 28 defining an elongated channel 30 within the syringe housing 16. As best shown in FIG. 3, the pre-filled syringe 14 includes a barrel 32 having a proximal end 34 and a distal end 36 and that defines an interior 38 configured to hold one or more medicamentstherein. A needle 40 may be affixed to the distal end 36 of the barrel 32, while a stopper 42 may be slidably received within the interior 38 of barrel 32, to allow for the one or more medicaments to be expelled through needle 40. The stopper 42 may be displaced by a plunger rod 44, under the influence of the injector body 18, as described in further detail below. The plunger rod 44 has a proximal end 46 that may be actuated by the injector body 18 and a distal end 48 configured to engage the stopper 42.

[0043] In loading the pre-filled syringe 14 into syringe housing 16, the injector body 18 may be rotated to the open position, so as to expose a proximal opening 50 of the elongated channel 30 and enable loading of a pre-filled syringe 14 into the elongated channel 30. With the channel 30 of interior carrier 28 exposed, the barrel 32 is placed within the interior carrier 28. The prefilled syringe 14 is received within interior carrier 28 such that the plunger rod 44 extends out past the proximal end 24 of the syringe housing 16, thereby providing for interaction of the injector body 18 with the syringe 14.

[0044] According to aspects of the disclosure, a displaceable 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 enclose needle 40, and one or more arms 56 extending proximally from the tubular portion 54. Needle cover 52 may be displaceable, in a telescoping manner, relative to syringe housing 16, from a pre-use position, in which needle cover 52 extends a first distance beyond the distal end 26 of syringe housing 16 and encloses the needle 40 of syringe 14, to a use position, in which needle cover 52 is displaced proximally, exposing needle 40, to a post-use position, in which needle cover 52 extends a second distance beyond distal end 26 of syringe housing 16 and encloses needle 40. Needle cover 52 may be biased to a distal position by a needle cover spring 58. In the post-use position, the needle cover 52 is locked, and needle 40 cannot be re-exposed.

[0045] According to aspects of the disclosure, the injector body 18 includes a slider housing 60 having a proximal end 62 and a distal end 64, a slider assembly 66 positioned within the slider housing 60 and movable axially relative to the slider housing 60, rollers 68 that engage with the slider assembly 66 and slider housing 60, and a trigger cap 70 positioned at the proximal end 62 of the slider housing 60, with the trigger cap 70 configured to interact with the slider assembly 66 when depressed.

[0046] The distal end 64 of the slider housing 60 is pivotably coupled to the proximal end 24 of the syringe housing 16 via a pivot member 72, such as a pivot pins that couple the slider housing 60 to the syringe housing 16 and 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 entirety of the injector body 18) relative to the syringe housing 16, with rotation provided 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, so as to provide access to the interior carrier 28 of syringe housing 16 and allow for insertion of a pre-filled syringe 14 therein. In some embodiments, the slider housing 60 (and the entirety of the injector body 18) may be rotated by 90 degrees or more relative to the syringe housing 16 when in the open position.

[0047] The slider housing 60 includes an interior surface 74 having a number of features thereon that interact with other components of the injector body 18. The interior surface 74 of slider housing 60 may include a pair of axial channels 76 formed therein, on opposing sides of the slider housing 60, within which rollers 68 may translate during operation of the autoinjector 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 interior surface 74 of slider housing 60 also defines a central channel 80 therein within which portions of the slider assembly 66 may move relative to the slider housing 60, with a proximal end of the central channel 80 including a spring retention member 82 and a deflectable hook structure 84 configured to interact with the slider assembly 66, as explained in further detail below.

[0048] The slider assembly 66 of injector body 18 is positioned within slider housing 60 and extends lengthwise therein, with a distal end 86 of slider assembly 66 positioned near the distal end 64 of slider housing 60 and a proximal end 87 of slider assembly 66 positioned near the proximal end 62 of 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.

[0049] In an exemplary embodiment, the guide pin 88, cylindrical end member 92, step 94, and retaining arms 96 are formed as a single, integral member that, for example, may comprise a molded component. The cylindrical end member 92 is positioned at the distal end 86 of the slider assembly 66, with the cylindrical end member 92 having a closed bottom surface 98 and defining a chamber 100 therein, and with the chamber 100 receiving a portion of spring 90 therein. The guide pin 88 extends proximally out from the closed bottom surface 98 (from the distal end 86 of slider assembly 66) and through the chamber 100 to the proximal end 87 of the slider assembly 66. The step 94 of slider assembly 66 extends radially outward from the cylindrical end member 92 at a top surface thereof, with the pair of retaining arms 96 connected to the step 94 and extending out proximally therefrom. Each of the retaining arms 96 includes a hooked proximal end 101 that engages the seat 78 of slider housing 60 when the sliderassembly 66 is at the first position, so as to prevent further distal travel of the slider assembly 66, as explained in more detail below.

[0050] The guide pin 88 of slider assembly 66 extends between the distal end 86 and the proximal end 87 of the slider assembly 66 and is configured to guide movement of the slider assembly 66 within the slider housing 60 - with the slider assembly 66 movable axially relative to the slider housing 60 between a first position (FIGS. 2A and 2B and FIGS. 5 A and 5B) and a second position (FIG. 3 and FIGS. 4A and 4B), where the second position is distal from the first position. The spring 90 is positioned on the guide pin 88 and is actuatable between an extended state (FIGS. 2A and 2B and FIGS. 5A and 5B) and a compressed state (FIG. 3 and FIGS. 4A and 4B), with the spring retention member 82 functioning as a stop to retain the spring 90 in place. In operation of the auto-injector 12, the spring 90 is in the extended state with the slider assembly 66 in the first position and is in the compressed state with the slider assembly 66 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 transitioning from the compressed state to the extended state. A tongue structure 102 is formed on the guide pin 88 adjacent the proximal end 87 of the slider assembly 66, with the tongue structure 102 configured to engage with the deflectable hook structure 84 of 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 a back / proximal face of the hook structure 84, so as to lock the slider assembly 66 in the second position and maintain the spring 90 in the compressed state when the injector body 18 is rotated from the open position to the closed position. According to embodiments, the tongue structure 102 may be configured as a disc-shaped protrusion that extends out radially from the guide pin 88 and the back / proximal face of the hook structure 84 may have a horizontal surface that retains the disc-shaped protrusion, although it is recognized that the tongue structure 102 and / or hook structure 84 could have other suitable shapes.

[0051] The rollers 68 of injector body 18 are positioned in the pair of axial channels 76 formed in slider housing 60, with a respective roller 68 positioned in each of the axial channels 76. The rollers 68 are configured so as to be movable axially along the axial channels 76. Movement of the rollers 68 is effected by rotation of the connection rods 20 when the injector body 18 is rotated relative to the syringe housing 16, as each connection rod 20 is pivotably connected to the syringe housing 16 at a first end thereof (e.g., on an outer surface of the syringe housing 16, such as via a pair of rod pivot pins 106) and is pivotably connected to a respective roller 68 at a second end thereof (e.g., with a circular end positioned about a portion of roller68). The collection of the connection rods 20 and rollers 68 thus effectively operate as a slidercrank mechanism, where rotation of the connection rods 20 (i.e., the “crank”) is translated into a linear motion of the rollers 68 (i.e., the “slider”) within the slider housing 60, along the pair of axial channels 76. The rollers 68 are positioned within channels 76 so as to be distal to the step 94 of the slider assembly 66, with the rollers 68 abutting the step 94 as the auto-injector 12 is transitioned from the initial closed state to the open state, such that an axial translation of the rollers 68 in the proximal direction causes the slider assembly 66 to also move proximally within the slider housing 60. More specifically, when the auto-injector 12 is transitioned from the initial closed state to the open state (responsive to rotating of the injector body 18 relative to the syringe housing 16), the connection rods 20 are caused to rotate - with the rotation of connection rods 20 causing the rollers 68 to move proximally within channels 76, and the rollers 68 in turn pushing against and causing the slider assembly 66 to move proximally within slider housing 60.

[0052] As indicated above, a trigger cap 70 is positioned at the proximal end 62 of the slider housing 60, with the trigger cap 70 accessible at the proximal end of the injector body 18, such that is may be depressed by a user. The trigger cap 70 extends internally into the slider housing 60 such that it is able to interact with the slider assembly 66 when depressed. That is, when the trigger cap 70 is depressed, the trigger cap 70 causes the deflectable hook structure 84 to move radially outwards, with the radially outward movement of hook structure 84 releasing the tongue structure 102 from its position proximal to hook structure 84 (i.e., release tongue structure 102 from the back / proximal face of the hook structure 84). With the tongue structure 102 released, the slider assembly 66 becomes 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 pre-filled syringe 14 into the patient and the plunger rod 44 further into barrel 32 to dispense the medicament.

[0053] With reference to the figures, activation of drug delivery device 10 will now be described. The reusable auto-injector 12 is provided in an initial closed state (FIG. 1A and FIGS. 2A and 2B), where the injector body 18 is aligned with the syringe housing 16. A user may then grasp the auto-injector 12 and cause the injector body 18 to pivot relative to the syringe housing 16, so as to transition the auto-injector 12 from the initial closed position to an open position (FIG. IB and FIG. 3). In pivoting to the open position, the injector body 18 pivots about pivot pins 72 that couple the slider housing 60 to the syringe housing 16. Once the autoinjector 12 is in the open position - with the injector body 18 rotated 90 degrees or more relativeto the syringe housing 16 - a pre-filled syringe 14 may be inserted into the syringe housing 16 and secured within the interior carrier 28 of the syringe housing 16 - with a proximal end of the syringe (i.e., the plunger rod 44) sticking out past the proximal end 24 of the syringe housing 16.

[0054] In transitioning the auto-injector 12 from the initial closed position to the open position, the connection rods 20 of the auto-injector 12 are caused to rotate in association with the injector body 18. Rotation of the connection rods 20 causes a related linear movement of rollers 68 positioned within the slider housing 60 of injector body 18 - with the connection rods 20 and rollers 68 thus functioning as a slider-crank mechanism in auto-injector 12. The rollers 68 are caused to move proximally within axial channels 76 of the slider housing 60 as the injector body 18 is rotated to its open position, and this proximal movement of the rollers 68 within slider housing 60 pushes / causes slider assembly 66 to also move proximally within the slider housing 60. That is, the rollers 68 are caused to abut against the step 94 of slider assembly 66, such that an axial translation of the rollers 68 in the proximal direction causes the slider assembly 66 to also move proximally within the slider housing 60. As the injector body 18 is rotated to its open position, the slider assembly 66 is thus caused to move proximally from a first position (FIGS. 2A and 2B) to a second position (FIG. 3).

[0055] As the slider assembly 66 is moved to its second position, the guide pin 88 translates within the central channel 80 of slider housing 60. Upon the slider assembly 66 reaching the second position, the tongue structure 102 formed on the guide pin 88 is pressed against and proximally past the deflectable hook structure 84 of slider housing 60, such that the slider assembly 66 becomes 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 against the back / proximal face of the hook structure 84, so as to lock the slider assembly 66 in the second position and maintain the spring 90 in the compressed state when the injector body 18 is rotated from the open position to the closed position.

[0056] Also, as the slider assembly 66 is moved to its second position, the spring 90 positioned about guide pin 88 begins to compress from its extended position toward its compressed position. That is, the spring 90 is positioned between spring retention member 82 of slider housing 60 (on the proximal end of spring 90) and the closed bottom surface 98 of cylindrical end member 92 (on the distal end of spring 90), with the distal end of spring 90 retained within chamber 100 of the cylindrical end member 92, such that movement of the slider assembly 66 toward the second position causes the spring 90 to compress. Upon the slider assembly 66 reaching the second position, the slider assembly 66 becomes locked in thesecond position due to interaction of the tongue structure 102 and deflectable hook structure 84, with the spring 90 thus also locking in its compressed state.

[0057] With the slider assembly 66 locked in the second position and the spring 90 thereof “loaded” in its compressed state, the injector body 18 may be rotated back from the open position to the closed position (i.e., a closed injection position, FIG. 1C and FIGS. 4A and 4B). As the injector 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 hook structure 84, with the spring 90 thus also remaining its compressed state. Upon the injector body 18 being rotated back to the closed injection position, the closed bottom surface 98 of cylindrical end member 92 of slider assembly 66 is positioned so as to be adjacent to the proximal end of the plunger rod 44 of 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.

[0058] When it is desired for the drug delivery device 10 to perform an injection, a user may depress the trigger cap 70 of auto-injector 12. When the trigger cap 70 is depressed, the trigger cap 70 causes the deflectable hook structure 84 to move radially outwards, with the radially outward movement of hook structure 84 releasing the tongue structure 102 from its position proximal to hook structure 84, such that the slider assembly 66 becomes unlocked and the spring 90 is able to 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 (FIGS. 5A and 5B), with the hooked proximal end 101 on each of the retaining arms 96 engaging the seat 78 of slider housing 60 to stop movement of the slider assembly 66 at the first position.

[0059] In moving back toward the first position, the closed bottom surface 98 of cylindrical end member 92 (of 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 plunger rod 44a. The force applied by the closed bottom surface 98 of cylindrical end member 92 is sufficient to initially cause the needle 40 of pre-filled syringe 14 to pierce the dermal surface of the patient and then subsequently push the plunger rod 44 further distally into the interior of syringe barrel 32 to cause a medicament within the pre-filled syringe 14 to dispense.

[0060] Beneficially, embodiments of the disclosure thus provide a reusable auto-injector for drug delivery. The auto-injector includes a pivotable structure that automatically loads / compresses a spring of the auto-injector as the auto-injector is rotated and opened to introduce a pre-filled syringe therein. The rotation of the auto-injector (for introduction of the syringe) and the spring compression is thus merged into a single step that reduces the numberof steps required for assembly and use of the auto-injector, thereby improving as user experience with the device.

[0061] Although the 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 is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

THE INVENTION CLAIMED IS1. A reusable auto-injector for drug delivery, the auto-injector comprising: a syringe housing having a proximal end and a distal end and defining an interior carrier configured to receive a pre-filled syringe therein; an injector body pivotably connected to the syringe housing, the injector body pivotable between a closed position where the injector body is aligned with the syringe housing and an open position where the injector body is rotated relative to the syringe housing, the injector body comprising: a slider housing comprising a proximal end and a distal end, the distal end of the slider housing pivotably coupled to the proximal end of the syringe housing via a pivot member; a slider assembly positioned 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 movement of the slider assembly within the slider housing; and a spring positioned on the guide pin and actuatable between an extended state and a compressed state, with the spring in the extended state with the slider assembly in the first position and in the compressed state with the slider assembly in the second position, and wherein the spring drives the slider assembly distally from the second position back to the first position when transitioning from the compressed state to the extended state; and a pair of connecting rods connecting the syringe housing to the injector body, with the pair of connection rods pivotable relative to each of the syringe housing and the injector body, wherein the pair of connecting rods interact with the slider assembly such that the spring is actuated to the compressed state upon pivoting of the injector body to the open position.

2. The auto-injector of claim 1, wherein the slider housing defines a central channel therein that receives the guide pin and the spring, and wherein a proximal end of the central channel includes: a spring retention member thereon configured to retain the spring within the central channel; and a deflectable hook structure configured to interact with the slide assembly.

3. The auto-injector of claim 2, wherein the slider assembly includes a distal end and a proximal end, the guide pin extending between the distal end and the proximal end, and wherein the slider assembly further comprises: a cylindrical end member positioned at the distal end of the slider assembly, the cylindrical end member having a closed bottom surface and defining a chamber therein, with the guide pin extending proximally out from the closed bottom surface and through the chamber 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 formed on the guide pin adjacent the proximal end of the slider assembly, the tongue structure configured to engage with the deflectable hook structure when the slider assembly is moved to the second position, to lock the slider assembly in the second position and the spring in the compressed state.

4. The auto-injector of claim 3, wherein a distal end of the spring is positioned within the chamber of the cylindrical end member, to retain the spring in place and enable compression of the spring when the slider assembly is moved from the first position to the second position.

5. The auto-injector of claim 3, wherein the slider housing comprises an interior surface having a pair of axial channels formed therein, the pair of axial channels positioned on opposing sides of the slider housing, and wherein the injector body further comprises a roller positioned in each of the pair of axial channels so as to be movable axially along the axial channels, with a respective connecting rod of the pair of connecting rods pivotably connected to each roller, such that the pair of connecting rods cause the rollers to translate axially along the pair of axial channels.

6. The auto-injector of claim 5, wherein the rollers abut the step of the slider assembly, such that an axial translation of the rollers by the pair of connecting rods causes the slider assembly to move axially within the slider housing.

7. The auto-injector of claim 3, wherein the tongue structure engages with the deflectable hook structure when the slider assembly is moved to the second position, such that the slider assembly is locked in the second position and the spring is locked in thecompressed state when the injector body is rotated from the open position to the closed position.

8. The auto-injector of claim 3, wherein the injector 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, 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 the compressed state to the extended state and cause the slider assembly to move from the second position to the first position.

9. The auto-injector of claim 3, wherein the syringe housing comprises an interior carrier defining an elongated channel within the syringe housing, and wherein a proximal opening of the elongated channel is exposed when the injector body is in the open position, so as to enable loading of a pre-filled syringe into the elongated channel.

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

11. The auto-injector of claim 9, further comprising: a syringe housing spring positioned within the elongated channel and configured to encircle a barrel of the pre-filled syringe when inserted into the elongated channel; and a needle cover having a proximal end, a distal end comprising an opening, and a sidewall therebetween, the needle cover 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 protrudes 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 auto-injector of claim 1, wherein when transitioning from the compressed state to the extended state, the spring generates a force sufficient to cause a needle of the pre-filled syringe to pierce the dermal surface of a patient and cause a medicament within the pre-filled syringe to dispense.

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

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

15. The auto-injector of claim 1, wherein the slider housing comprises a seat formed within an interior volume thereof, and wherein the slider assembly further comprises a pair of retaining arms connected to the step and extending out proximally therefrom, each of the pair of retaining arms including a hooked proximal end that engages the seat to when the slider assembly is at the first position, so as to prevent further distal travel.

16. The auto-injector of claim 1, wherein the pair of connecting rods translates a rotational motion of the injector body to a linear movement of the slider assembly.

17. A drug delivery device, comprising: an auto-injector comprising: a syringe housing having a proximal end and a distal end and defining an interior carrier configured to receive a pre-filled syringe therein; an injector body pivotably connected to the syringe housing, the injector body pivotable between a closed position where the injector body is aligned with the syringe housing and an open position where the injector body is rotated relative to the syringe housing, the injector body comprising: a slider housing comprising a proximal end and a distal end, the distal end of the slider housing pivotably coupled to the proximal end of the syringe housing via a pivot member; a slider assembly positioned 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 movement of the slider assembly within the slider housing; and a spring positioned on the guide pin and actuatable between an extended state and a compressed state, with the spring in the extended state with the slider assembly in the first position and in the compressed state with the slider assemblyin the second position, and wherein the spring drives the slider assembly distally from the second position back to the first position when transitioning from the compressed state to the extended state; and a pair of connecting rods connecting the syringe housing to the injector body, with the pair of connection rods pivotable relative to each of the syringe housing and the injector body, wherein the pair of connecting rods interact with the slider assembly such that the spring is actuated to the compressed state upon pivoting of the injector body to the open position; and a pre-filled syringe received at least partially within the interior carrier of the syringe housing, the pre-filled syringe comprising: a syringe barrel including a proximal end, a distal end, and a sidewall defining an interior containing a medicament; a needle arranged at the distal end of the syringe barrel and in fluid communication with the syringe interior; and a plunger assembly movable within the syringe interior and comprising a plunger rod and a stopper, the stopper arranged at a distal end of the plunger rod.

18. The drug delivery device of claim 17, wherein a proximal end of the plunger rod extends out proximally past the syringe housing when the pre-filled syringe is received at least partially within the interior carrier of the syringe housing, so as to extend into the slider housing when the injector body is in the closed position.

19. The drug delivery device of 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 the proximal end of the plunger rod.

20. The drug delivery device of claim 19, wherein upon the trigger cap being depressed and thereby 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, the closed bottom surface of the cylindrical end member distally advances the plunger rod into the syringe interior, so as to cause injection of the medicament.

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