Reusable auto-injection device with single drive spring

Abstract

A reusable auto-injector is provided that includes a housing that receives a pre-filled syringe, a pusher movable within the housing, a spring positioned on the pusher, and a traveler movably positioned within the housing, distal to the pusher. A trigger member operable in locked and unlocked positions selectively engages the traveler. When the trigger member is actuated from the locked position to the unlocked position, the spring transitions from a loaded state to an unloaded state to implement two injector movements. In a first injector movement, the spring drives the pusher distally, to move the traveler distally through the housing and cause a needle of the pre-filled syringe to advance out distally from the housing, and in a second injector movement, the spring drives the pusher distally through the traveler to force a plunger further into a barrel of the pre-filled syringe, to dispense a solution from the pre-filled syringe.

Description

REUSABLE AUTO-INJECTION DEVICE WITH SINGLE DRIVE SPRINGCROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Chinese Patent Application No. 202410920988.7 entitled “Reusable Auto-Injection Device with Single Drive Spring” filed July 10, 2024, 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 single drive spring 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 may require several distinct user actions in order perform the injection, which may include performing a first action that causes a needle of the injector to penetrate through the dermal surface and performing a second action that causes the injector to dispense the medicament into the patient. This multi-step injection process, along with the accompanying structure of the auto-injector that enables this process, is thus recognized as being complex and potentially 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 and / or components required for 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 housing comprising a distal housing portion and a proximal housing portion, the housing configured to receive a pre-filled syringe therein that includes a barrel, a plunger movable within the barrel, and a needle. The auto-injector also includes an elongated pusher positioned within the proximal housing portion and movable axially relative thereto, the pusher comprising an end member at a distal end thereof. The auto-injector further includes a spring positioned on the pusher and extending between a proximal end of the proximal housing portion and the end member, the spring actuatable between a loaded state and an unloaded state. A traveler is positioned within the housing, distal to the pusher, and movable axially relative to the housing, the traveler defining a hollow interior. The auto-injector still further includes a trigger member actuatable between a locked position and an unlocked position, with the trigger member engaging the traveler when in the locked position and disengaging the traveler when in the unlocked position. Upon the trigger member being actuated from the locked position to the unlocked position, the spring transitions from the loaded state to the unloaded state to implement a first injector movement where the spring drives the pusher distally, with the pusher moving the traveler distally through the housing and the traveler, in turn, advancing the needle of the pre-filled syringe out distally from the housing, and implement a second injector movement upon the needle advancing out distally from the housing, where the spring drives the pusher distally through the hollow interior of the traveler, with the pusher forcing the plunger of the pre-filled syringe further into the barrel, to dispense a solution out from the pre-filled syringe.

[0007] In certain configurations, the traveler includes a tubular main body defining a hollow interior, an annular flange formed circumferentially on the main body at a proximal end thereof and extending radially outward therefrom, the proximal flange and the end member having an interference therebetween, and a pair of deflectable arms formed on the main body that are deflectable radially outward relative to the main body.

[0008] In certain configurations, the auto-injector further includes a dose ring positioned within the housing, between the distal housing portion and the proximal housing portion, the dose ring comprising a tubular structure having an inner diameter greater than an outer diameter of the cylindrical main body and less than an outer diameter of the proximal flange, such that a distal movement of the traveler through the housing is limited by the dose ring.

[0009] In certain configurations, the distal housing portion and the proximal housing portion are separate members, and wherein the dose ring joins the distal housing portion and the proximal housing portion.

[0010] In certain configurations, the dose ring comprises a threaded tubular structure that engages each of the distal housing portion and the proximal housing portion via a threaded engagement.

[0011] In certain configurations, a position of the distal housing portion relative to the proximal housing portion is controllable based on a positioning of the distal housing portion and / or the proximal housing portion on the dose ring, via the threaded engagement therebetween.

[0012] In certain configurations, with the trigger member in the locked position, the pair of deflectable arms are in a radially inward position, such that the pair of deflectable arms engage a distal end surface of the end member.

[0013] In certain configurations, with the pair of deflectable arms in the radially inward position, the distal end surface of the end member is separated from a proximal end of the plunger.

[0014] In certain configurations, the proximal housing portion comprises an inner surface including a pair of slide ribs formed thereon that extend axially along the inner surface and protrude radially inward, the pair of slide ribs engaging the pair of deflectable arms and preventing deflection thereof radially outward relative to the main body, so as to retain the pair of deflectable arms in the radially inward position.

[0015] In certain configurations, the slide ribs extend distally along the inner surface from a first longitudinal location to a second longitudinal location, the second longitudinal location adjacent a proximal edge of the dose ring.

[0016] In certain configurations, with the trigger member in the unlocked position and as part of the first injector movement, the spring pushes the end member distally against a proximal end surface of the pair of deflectable arms when in the radially inward position, to advance the traveler distally through the housing.

[0017] In certain configurations, as part of the first injector movement, the dose ring limits the distal advancement of the traveler, with the annular flange engaging the dose ring to stop distal advancement of the traveler, thereby controlling a penetration depth of the needle.

[0018] In certain configurations, with the trigger member in the unlocked position and as part of the second injector movement, the pair of deflectable arms are in a radially outward position after having moved distal to the slide ribs, such that the pair of deflectable armsdisengage from the distal end surface of the end member, enabling the pusher to advance distally through the traveler and push the plunger of the pre-filled syringe further into the barrel.

[0019] In certain configurations, the auto-injector includes a blocker ring positioned within the hollow interior of the traveler, at a location between a distal end and a proximal end of the traveler, and wherein the blocker ring has an inner diameter smaller than an outer diameter of the end member.

[0020] In certain configurations, as part of the second injector movement, the pusher advances distally through the traveler until coming into contact with a proximal end of the blocker ring, with the end member engaging the blocker ring to stop distal advancement of the pusher.

[0021] In certain configurations, the trigger member comprises a pair of trigger arms joined to the proximal housing portion and formed on opposing sides thereof, each of the pair of trigger arms comprising a latch end that engages the proximal flange and a finger-press end 40 engageable by a user, the finger press end being depressible inward to release the latch end from engagement with the proximal flange.

[0022] In certain configurations, the auto-injector includes a trigger lock positionable on the proximal housing portion, the trigger lock comprising a plurality of locking arms that selectively engage the pair of trigger arms to prevent depression of the finger press end thereof.

[0023] In certain configurations, the trigger lock is rotatable about the proximal housing portion to selectively engage and disengage the plurality of locking arms with the pair of trigger arms.

[0024] In certain configurations, the end member comprises an elastomeric retaining ring positioned circumferentially about the end member, the retaining ring providing circumferential interference with the proximal flange.

[0025] Also provided herein is a method of operating an auto-injector of claim 1. The method includes actuating the trigger member from the locked position to the unlocked position to release the traveler from engagement with the proximal housing portion, responsive to which the auto-injector automatically implements the first injector movement and the second injector movement in succession. In implementing the first injector movement, the spring drives the pusher distally, with the pusher moving the traveler distally through the housing and the traveler, in turn, advancing the needle of the pre-filled syringe out distally from the housing. In implementing the second injector movement, the spring drives the pusher distally through the hollow interior of the traveler, with the pusher forcing the plunger of the pre-filled syringe further into the barrel, to dispense a solution out from the pre-filled syringe.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a perspective view of a drug delivery device, according to a non-limiting embodiment described herein;

[0027] FIG. 2 is an exploded view of the drug delivery device of FIG. 1 ;

[0028] FIG. 3A is a first cross-sectional view of the drug delivery device of FIG. 1, with the device in a pre-injection position;

[0029] FIG. 3B is a second cross-sectional view of the drug delivery device of FIG. 1, with the device in a pre-injection position;

[0030] FIG. 4 is a detail view of area I of FIG. 3A;

[0031] FIG. 5 is a detail view of area II of FIG. 3B;

[0032] FIG. 6A is a first cross-sectional view of the drug delivery device of FIG. 1, taken after a first injector movement where the needle of the pre-filled syringe is advanced out of the housing;

[0033] FIG. 6B is a second cross-sectional view of the drug delivery device of FIG. 1, taken after a first injector movement where the needle of the pre-filled syringe is advanced out of the housing;

[0034] FIG. 7A is a cross-sectional view of the drug delivery device of FIG. 1, taken during a second injector movement where the plunger of the pre-filled syringe is pushed into the syringe barrel;

[0035] FIG. 7B is a second cross-sectional view of the drug delivery device of FIG. 1, taken after a second injector movement where the plunger of the pre-filled syringe is pushed into the syringe barrel;

[0036] FIG. 8 is a cross-sectional view of a portion of the drug delivery device of FIG. 1, showing the distal housing portion removed from the proximal housing portion and turned around, so as to be used as a tool to re- set the pusher and spring to an initial position;

[0037] FIG. 9A is a perspective view of a portion of the drug delivery device of FIG. 1 , showing a trigger guard in a first position; and

[0038] FIG. 9B is a perspective view of a portion of the drug delivery device of FIG. 1 , showing a trigger guard in a second position.DESCRIPTION OF THE INVENTION

[0039] 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 apparentto 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.

[0040] 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 specified to 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.

[0041] 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.

[0042] 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.

[0043] With reference now to the figures, shown is a drug delivery device 10 that includes a reusable auto-injector 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 includes a housing 16 that, in some embodiments, may be formed of a transparent or semi-transparent material that provides for viewing of the syringe 14 within the housing 16, such that a positioning of the syringe may be determined. In other embodiments, the housing 16 could be formed of an opaque material.

[0044] The housing 16 may be characterized as including a distal housing portion 18 and a proximal housing portion 20. The distal housing portion 18 includes a distal end 22 and a proximal end 24, each of which is formed as an open end. The distal housing portion 18 may have a stepped configuration, with the proximal end 24 having an increased diameter as compared to the distal end 22, with the stepped configuration accommodating positioning of the pre-filled syringe 14 therein and limiting movement of the syringe. The proximal housing portion 20 includes a distal end 26 and a proximal end 28, with the distal end 26 configured as an open end and the proximal end 28 configured as a closed end. The proximal housing portion 20 may have a stepped configuration, with the proximal end 28 having a decreased diameter as compared to the distal end 26. The distal end 26 of proximal housing portion 20 has adiameter that is equal to the diameter of the proximal end 24 of distal housing portion 18, so as to provide for securing of the distal and proximal housing portions 18, 20, as explained further below. The proximal end 28 of proximal housing portion 20 has a reduced diameter as compared to the distal end 26, and the proximal end 28 of proximal housing portion 20 may define a central channel 30 (see FIGS. 3 A and 3B) therein configured to receive components that provide for automated actuation of the syringe 14 during use of the auto-injector 12, as explained in further detail below.

[0045] In some embodiments, the proximal housing portion 20 may include a trigger member 32 formed integrally therewith that is actuatable between a locked position and an unlocked position to control operation of the auto-injector 12. The trigger member 32 includes a pair of trigger arms 34 formed on opposing sides of the proximal housing portion 20, at a location between the distal end 26 and the proximal end 28. Each of the trigger arms 34 is joined to the proximal housing portion 20 at a pivot point 36, with the trigger arms 34 including a hooked latch end 38 distal of the pivot point 36 and a finger-press end 40 proximal of the pivot point 36 (see FIGS. 3A and 3B). With the trigger arms 34 in a default or at-rest position, the hooked latch end 38 of each trigger arm 34 extends into and through a respective hook opening 42 formed in the proximal housing portion 20, such that the hooked latch end 38 may engage an internal component of the auto-injector 12 and retain the auto-injector 12 in an initial or pre-injection state. When the finger-press ends 40 are depressed radially inwardly (i.e., toward a cylindrical outer wall of proximal housing portion 20), the trigger arms 34 are caused to pivot about the pivot points 36, causing the hooked latch ends 38 to withdraw outwardly through the openings 42 and disengage from the internal component of the auto-injector 12, thereby enabling the auto-injector 12 to transition from its initial / pre-inj ection condition to an injection state, as explained in further detail below.

[0046] In embodiments where trigger arms 34 are formed on opposing sides of the proximal housing portion 20, a trigger lock 44 may be included on the proximal housing portion 20 to enable or inhibit actuation of the trigger arms 34. The trigger lock 44 may be positioned circumferentially about the proximal housing portion 20, with the trigger lock 44 including a plurality of (e.g., four) locking arms 46 that may selectively engage the pair of trigger arms 34 to prevent depression of the finger-press end 40 thereof. That is, the trigger lock 44 may be rotated about the proximal housing portion 20 to selectively align the locking arms 46 with the trigger arms 34 to prevent depression of the finger-press end 40 thereof, as best shown in FIGS. 9 A and 9B. In some embodiments, a locking arm 46 may be positioned between a trigger arm 34 and the outer wall of proximal housing portion 20 to prevent depression of the finger-pressend 40, while in other embodiments a locking arm 46 may be positioned over a trigger arm 34 to prevent depression of the finger-press end 40. The trigger lock 44 therefore functions to prevent accidental actuation of the trigger arms 34 that could cause an undesired activation of the auto-injector 12.

[0047] According to aspects of the disclosure, the distal housing portion 18 and proximal housing portion 20 are formed as separate components that may be joined together via a dose ring 48 included in the auto-injector 12. The dose ring 48 may be positioned between the proximal end 24 of the distal housing portion 18 and the distal end 26 of the proximal housing portion 20 to join the housing portions together, with the dose ring 48 configured as a threaded tubular structure having a threaded outer surface 50 configured to engage a threaded inner surface of each of the distal housing portion 18 and the proximal housing portion 20 via a threaded engagement. In certain configurations, a position of the distal housing portion 18 relative to the proximal housing portion 20 may be controllable based on a positioning of the distal housing portion 18 and / or the proximal housing portion 20 on the dose ring 48 - i.e., by an amount by which the distal housing portion 18 and / or the proximal housing portion 20 are threaded onto the dose ring 48. As explained in further detail below, by controlling the positioning of the distal housing portion 18 relative to the proximal housing portion 20, a depth of penetration of the pre-filled syringe 14 into a patient may be controlled, as may be desired based on a size of the syringe or other factors.

[0048] The housing 16 of auto-injector 12 is sized and configured to provide for positioning therein of the pre-filled syringe 14 and other components that provide for automated actuation of the syringe during use of the auto-injector 12. The pre-filled syringe 14 may be initially loaded into the proximal housing portion 20, with the distal housing portion 18 then connected to the proximal housing portion 20 (via dose ring 48) to secure the syringe in-place. As illustrated in FIG. 2, the pre-filled syringe 14 generally includes a barrel 52 having a proximal end 54 (with a flange 55) and a distal end 56 and that defines an interior 58 configured to hold one or more medicaments therein. A needle 60 may be affixed to the distal end 56 of the barrel 52, while a stopper 62 may be slidably received within the interior 58 of barrel 52, to allow for the one or more medicaments to be expelled through needle 60. The stopper 62 may be displaced by a plunger 64, under the influence of the auto-injector 12, as described in further detail below. The plunger 64 has a proximal end 66 that may be actuated by the auto-injector 12 and a distal end 68 configured to engage the stopper 62.

[0049] With reference to FIGS. 3-8, cross-sectional views of the drug delivery device 10 are shown during various stages of operation of the device, so as to better illustrate the constructionthereof. As shown therein, the auto-injector 12 includes an arrangement of components within housing 16 that provide for automated actuation of the pre-filled syringe 14 during use of the auto-injector 12.

[0050] The auto-injector 12 includes an elongated pusher 70 that is positionable within the proximal housing portion 20, with the pusher 70 being movable axially relative to the housing 16 of auto-injector 12. The pusher 70 is formed of an elongated rod 72 and an end member 74 positioned at a distal end of the elongated rod. The end member 74 may be configured as a cupshaped member having a closed distal end surface 76 and a circumferential lip 78 that extends back proximally from the distal end surface 76, so as to define a chamber 80 within the end member 74. In some embodiments, a groove 82 is formed on an outer surface of the end member 74 that extends circumferentially thereabout. The groove 82 is configured to receive and hold therein a retaining ring 84 positioned about the end member 74. The retaining ring 84 may be formed of an elastomeric material (or other flexible material) that is deformable when force is applied thereto. When positioned within groove 82, the retaining ring 84 extends radially out from the outer surface of end member 74, to provide an area of increased diameter on end member 74 that, as described in further detail below, aids in retaining the pusher 70 in place during use of the auto-injector 12.

[0051] A spring 86 is positioned on the pusher 70, about the elongated rod. The spring 86 may have any of a number of suitable coiled spring configurations. In some embodiments, the spring 86 may have a constant pitch and diameter. Alternatively, the spring 86 may include variations on pitch, diameter, and / or shape, for example. The spring 86 is positioned so as to extend between the closed proximal end 28 of the proximal housing portion 20 and the distal end of the elongated rod 72 - with the spring 86 received and retained within the chamber 80 defined by the cup-shaped end member 74. The spring 86 is actuatable between a compressed position and an extended (or “resting”) position, with the spring 86 being in a loaded state when in the compressed position and in an unloaded state when in the extended position. The state of the spring 86 is controlled by positioning of the pusher 70 within housing 16, as explained in further detail below.

[0052] A traveler 88 is positioned within the housing 16, distal to the pusher 70, and is movable axially relative to the housing 16. According to aspects of the disclosure, the traveler 88 is structured to include a tubular main body 90 open at both ends thereof and that defines a hollow interior 92. The tubular main body 90 includes an inner surface 94 and an outer surface 96. The tubular main body 90 is configured such that an inner diameter thereof (defined by inner surface 94) is larger than an outer diameter of the end member 74 of pusher 70 - i.e.,larger than an outer diameter of end member 74 and an outer diameter of retaining ring 84 - such that the pusher 70 may be advanced through the hollow interior 92 of the traveler 88 during operation of the auto-injector 12, as explained in further detail below. The tubular main body 90 is further configured such that an outer diameter thereof (defined by outer surface 96) is smaller than an inner diameter of the dose ring 48, such that the tubular main body 90 may be advanced into / through the dose ring 48 when the traveler 88 is advanced distally within housing 16, as explained in further detail below.

[0053] An annular flange 98 is formed on the tubular main body 90 of traveler 88 at a proximal end 100 thereof, with the flange 98 extending circumferentially about the opening at the proximal end 100 of the main body 90. The flange 98 extends radially outward from the outer surface 96 of main body 90, to provide an increased outer diameter on the traveler 88 at the proximal end 100. An outer diameter of the annular flange 98 is such that the flange cannot advance into / through the dose ring 48 when the traveler 88 is advanced distally within housing 16 - i.e., the outer diameter of annular flange 98 is greater than the inner diameter of the dose ring 48. Instead, when the traveler 88 is advanced distally within housing 16 and into dose ring 48, the annular flange 98 will abut the proximal end of the dose ring 48 and prevent further distal movement of the traveler 88, as explained in further detail below.

[0054] According to aspects of the disclosure, the annular flange 98 may include a flat proximal end surface 102 and an inner lip 104 that is positioned distally from the flat proximal end surface 102, so as to be inset therefrom toward the hollow interior 92. The inner lip 104 extends radially inward from the inner surface 94 of main body 90, to provide a reduced inner diameter relative to the inner surface 94. The opening defined by the inner lip 104 is sized such that the diameter thereof is greater than an outer diameter of the end member 74 of pusher 70, but is less than an outer diameter of the retaining ring 84 positioned on end member 74. That is, the diameter of the opening defined by inner lip 104 is less than an outer diameter of the retaining ring 84 positioned on end member 74, such that an interference is present between the retaining ring 84 and the inner lip 104 when the pusher 70 is brought into contact with the traveler 88 - with it recognized that this interference can be overcome and the pusher 70 advanced past the inner lip 104 (and into hollow interior 92 of traveler 88) when a distal force is applied to the pusher 70. In some embodiments, a sloped surface 106 may be provided on the flange 98 that extends between the flat proximal end surface 102 and the inner lip 104, with the sloped surface 106 being sloped downwardly and inwardly to the inner lip 104 to help in guiding the pusher 70 into and through the hollow interior 92 of the traveler 88 during operation of the auto-injector 12.

[0055] The traveler 88 also includes a pair of deflectable arms 108 that are formed on the main body 90, at a location between the proximal and distal ends of the main body 90. The deflectable arms 108 are formed on opposing sides of the tubular main body 90, with each arm positioned within a gap 110 formed in the main body 90 and extending generally in parallel with the main body 90. Each deflectable arm 108 has a first end 112 that is joined to the main body 90 and a free second end 114 that is not joined to the main body 90, such that the second end 114 may be deflected radially inward and / or outward when a force is applied to the deflectable arm 108 at or near the second end 114.

[0056] According to aspects of the disclosure, the second end 114 of each deflectable arm 108 includes a hooked end portion 116. When the deflectable arms 108 are in an initial, biased position, the hooked end portion 116 of each arm extends radially inward past an inner surface 94 of the tubular main body 90 - such that a distance between the hooked end portions 116 on the pair of opposing deflectable arms 108 is less than the outer diameter of the end member 74 of pusher 70. Thus, with the deflectable arms 108 in the biased position, the end member 74 of pusher 70 will abut the arms when the pusher 70 is brought into contact with the traveler 88 - with the deflectable arms 108 preventing advancement of the pusher 70 into and through the hollow interior 92 of the tubular main body 90.

[0057] In some embodiments, an inner surface 118 of the proximal housing portion 20 includes a pair of slide ribs 120 formed thereon that extend axially along the inner surface and protrude radially inward. The pair of slide ribs 120 are provided on the inner surface of the proximal housing portion 20 and extend generally from a location where the distal end 26 of proximal housing portion 20 engages dose ring 48 to a location where the diameter of the proximal housing portion 20 thereof changes (i.e., at the “stepped” feature of the proximal housing portion 20). The pair of slide ribs 120 function with the traveler 88 to retain the deflectable arms 108 in their radially inward biased position, with the slide ribs 120 engaging the deflectable arms 108 and preventing a radially outward deflection thereof to an unbiased position. When the traveler 88 is advanced distally through the housing 16 to a location where slide ribs 120 end, the deflectable arms 108 are then allowed to deflect radially outward to their unbiased position, where a distance between the hooked end portions 116 on the pair of opposing deflectable arms 108 is greater than the outer diameter of the end member 74 of pusher 70, such that the pusher 70 may be advanced into and through the hollow interior 92 of the tubular main body 90.

[0058] In some embodiments, a blocker ring 122 may be positioned within the hollow interior 92 of the tubular main body 90 of traveler 88, at a location between a distal end and aproximal end thereof. The blocker ring 122 may be joined to the main body 90 in a fixed manner. The blocker ring 122 has an inner diameter smaller than an outer diameter of the end member 74, such that the distal advancement of the pusher 70 through the hollow interior 92 of traveler 88 is limited. That is, the pusher 70 may advance distally through the traveler 88 until coming into contact with a proximal end / surface of the blocker ring 122, with the end member 74 then engaging the blocker ring 122 to stop distal advancement of the pusher 70.

[0059] As previously indicated, the auto-injector 12 includes a trigger member 32 that provides for activation of the auto-injector 12. For embodiments where the trigger member 32 is provided in the form of a pair of trigger arms 34 formed on proximal housing portion 20, the trigger arms 34 are actuatable between an initial default position and a deflected position, with the trigger arms 34 considered to be in a “locked” position when in the initial default position and in an “unlocked” position when actuated to the deflected position. When in the locked position, the hooked latch end 38 of each trigger arm 34 extends into and through a respective hook opening 42 formed in the proximal housing portion 20 and engages a distal surface of the annular flange 98 of traveler 88, so as to retain traveler 88 in position within the housing 16. When actuated to the unlocked position, the hooked latch end 38 of each trigger arm 34 is withdrawn from the respective hook opening 42 formed in the proximal housing portion 20 and disengages from the annular flange 98 of traveler 88, so as to allow for a distal movement of the traveler 88 through the housing 16 under influence from the pusher 70 and spring 86, as explained in detail below.

[0060] In operation of the auto-injector 12, upon the trigger member 32 being actuated from the locked position to the unlocked position, the spring 86 transitions from its loaded state to its unloaded state to implement a sequence of injector movements in the auto-injector 12 - here after referred to as a “first injector movement” and a “second injector movement.” In the first injector movement, the spring 86 begins to transition from its loaded to its unloaded state to drive the pusher 70 distally, with the pusher 70 in-tum moving the traveler 88 distally through the housing 16. The distal movement of the traveler 88 advances the pre-filled syringe 14 distally through the housing 16, such that the needle 60 of the pre-filled syringe 14 is caused to protrude out from the housing 16 and penetrate into / through the dermal surface of a patient. In the second injector movement, which is automatically initiated / performed upon completion of the first injector movement (i.e., upon the needle 60 advancing out distally from the housing 16), the spring 86 continues to transition from its loaded to its unloaded state to drive the pusher 70 distally through the hollow interior 92 of the traveler 88, with the pusher 70 forcing theplunger 64 of the pre-filled syringe 14 further into the barrel 52, to dispense a medicament or other solution out from the pre-filled syringe 14.

[0061] Accordingly, the auto-injector 12 functions to perform an injection procedure using only the single spring 86, with the spring 86 sequentially driving both needle penetration and dispensing of the medicament. Use / inclusion of the single spring 86 for driving both needle penetration and dispensing of the medicament simplifies the structure of the auto-injector 12 and simplifies the operation thereof, thus minimizing costs in the manufacture of the autoinjector 12 and reducing the number of steps required for use of the auto-injector 12, thereby improving as user experience with the drug delivery device 10.

[0062] With continued reference to FIGS. 3-8, a method of use of the drug delivery device 10 will now be described. The drug delivery device 10 is provided in an initial or pre-injection configuration, as shown in FIGS. 3 A and 3B, where a pre-filled syringe 14 comes loaded in the auto-injector 12. In the initial configuration of the drug delivery device 10, the pre-filled syringe 14 is loaded within auto-injector 12 such that flange 55 on the proximal end of barrel 52 is abutted against the distal end of tubular main body 90 of traveler 88 and such that the needle 60 is positioned within the distal housing portion 18. Also in the initial configuration of the drug delivery device 10, the auto-injector 12 is configured such that the trigger member 32 is in the locked position / configuration.

[0063] With the trigger member 32 in the locked position / configuration, the traveler 88 is retained in an initial / proximal position, at a rear or proximal end of the section of proximal housing portion 20 having the larger diameter. That is, the hooked latch end 38 of each trigger arm 34 extends into and through a respective hook opening 42 formed in the proximal housing portion 20 and engages a distal surface of the annular flange 98 of traveler 88, so as to retain the traveler 88 in its initial / proximal position within the housing 16. With the traveler 88 retained in an initial / proximal position, the deflectable arms 108 of the traveler 88 are retained in their radially inward biased position by the slide ribs 120 of proximal housing portion 20, with the slide ribs 120 engaging the deflectable arms 108 and preventing a radially outward deflection thereof to an unbiased position.

[0064] Further, with the trigger member 32 in the locked position / configuration, the pusher 70 is retained in an initial / proximal position within the central channel 30 at the proximal end 28 of proximal housing portion 20, with the spring 86 held in its compressed state between the closed proximal end 28 of proximal housing portion 20 and the end member 74 of pusher 70. The pusher 70 is retained in its initial / proximal position via the deflectable arms 108 of the traveler 88, as the deflectable arms 108 are retained in their radially inward biased position,such that the deflectable arms 108 make contact with the distal end surface 76 of end member 74 and function as a support that prevents distal movement of the pusher 70. Also, with the pusher 70 retained in its initial / proximal position, the retaining ring 84 on end member 74 is positioned proximally from the traveler 88, with the retaining ring 84 being in circumferential interference with the annular flange 98 of traveler 88 - with the support provided by deflectable arms 108 against end member 74 preventing the retaining ring 84 from being forced distally past the inner lip 104 of annular flange 98 (by a force of spring 86).

[0065] With the pusher 70 retained in its initial / proximal position, the end member 74 of pusher 70 remains separated from the plunger 64 of pre-filled syringe by a gap 124. That is, the contact between the deflectable arms 108 and the distal end surface 76 of end member 74 retains the pusher 70 in place, and the pre-filled syringe 14 is loaded into auto-injector such that the plunger 64 thereof is positioned to be separated from the end member 74 by a gap 124. This separation gap 124 functions to prevent an accidental actuation of the pre-filled syringe 14 that might occur if the end member 74 of pusher 70 and plunger 64 are in contact.

[0066] In order to activate the auto-injector 12, a user actuates the trigger member 32 from the locked position / configuration to the unlocked position / configuration. In one embodiment, the trigger member 32 is actuated to the unlocked position / configuration by depressing the finger-press end 40 of the trigger arms 34 radially inwardly. Depression of the finger-press end 40 of the trigger arms 34 in this manner causes the trigger arms 34 to pivot and the hooked latch ends 38 to withdraw outwardly through the hook openings 42 and disengage from the annular flange 98 of traveler 88.

[0067] With the hooked latch ends 38 disengaged from the annular flange 98 of traveler 88, the traveler 88 is released from the proximal housing portion 20 and allowed to move distally within housing 16. With the traveler 88 released, the spring 86 is released from being locked in its compressed / loaded state and the spring 86 thus beings to transition to its extended / unloaded state as part of a first injector movement. In the first injector movement, the spring 86 begins to transition from its loaded to its unloaded state to apply a force against the end member 74 of pusher 70, thereby driving the pusher 70 distally within housing 16. As the deflectable arms 108 of traveler 88 are locked in their radially inward biased position (by slide ribs 120) and make contact against the distal end surface 76 of end member 74, the distal movement of the pusher 70 causes the entire traveler 88 to move distally within housing 16, as shown in FIGS. 6A and 6B. With the traveler 88 moving distally within housing 16, the traveler 88 pushes against the flange 55 on barrel 52 - thereby causing the entirety of the pre-filled syringe 14 to be advanced distally through housing 16. The distal advancement of the pre-filledsyringe causes the needle 60 to protrude out from the distal end 22 of distal housing portion 18, such that the needle 60 penetrates into a patient as part of the first injector movement.

[0068] During the first injector movement, the traveler 88 moves distally through housing 16 (and the needle 60 is pushed distally out of the housing 16) until the annular flange 98 of traveler 88 comes into contact with a proximal end of the dose ring 48. When the annular flange 98 of traveler 88 comes into contact with the proximal end of the dose ring 48, further distal movement of the traveler 88 is prohibited, as the dose ring 48 is locked in place relative to the housing 16. This prohibiting of further distal movement of the traveler 88 also prohibits further advancement / protrusion of the needle 60 out from housing 16, such that a penetration depth of the needle 60 into the patient is also controlled.

[0069] As the annular flange 98 of traveler 88 comes close and / or into contact with the proximal end of the dose ring 48, as shown in FIGS. 6A and 6B, the traveler 88 has progressed distally through the housing 16 to a location where the slide ribs 120 of proximal housing portion 20 have terminated - such that the deflectable arms 108 of traveler 88 are no longer retained in their radially inward biased position and are allowed to deflect radially outward. When the deflectable arms 108 deflect radially outward, the deflectable arms 108 are no longer positioned against the distal end surface 76 of end member 74 on pusher 70.

[0070] Upon the annular flange 98 of traveler 88 coming into contact with the proximal end of the dose ring 48 and the deflectable arms 108 having deflected outward so as to no longer being positioned against the distal end surface 76 of end member 74, any further advancement of the pusher 70 (caused by the continued transitioning of the spring 86 from its compressed / loaded state to its extended / unloaded) causes the pusher 70 to move distally past the deflectable arms 108 and into the hollow interior 92 of the traveler 88 - thus initiating the second injector movement of the auto-injector 12. In initiating the second injector movement of the auto-injector 12, the distal force applied by spring 86 against pusher 70 first causes the end member 74 of pusher 70 to move distally past the inner lip 104 of annular flange 98, as shown in FIG. 7A, as the force applied by the spring 86 is greater than the interference force between the retaining ring 84 (on end member 74) and the inner lip 104. With the end member 74 pushed past the annular flange 98, the distal end surface 76 of end member 74 is thus brought into contact with the proximal end of the plunger 64 of pre-filled syringe 14.

[0071] During the second injector movement, and upon the end member 74 having moved past the annular flange 98 of traveler 88 and into contact with plunger 64, the spring 86 continues to apply force to the pusher 70 that causes the pusher 70 to advance further into / through the hollow interior 92 of traveler 88, as shown in FIG. 7B. As the pusher 70 isadvanced further into / through the hollow interior 92 of traveler 88, the end member 74 applies force against the plunger 64, so as to cause the plunger 64 to be advanced distally and further into the barrel 52 of pre-filled syringe 14. As the plunger 64 is advanced distally into the barrel 52, the stopper 62 at the distal end of plunger 64 also moves distally and forces medicament (or another solution) out from within the interior 58 of the barrel 52, with the medicament exiting the syringe through needle 60 and being injected into the patient.

[0072] In some embodiments, a distal-most advancement point of the pusher 70 into / through the hollow interior 92 of traveler 88 is controlled or limited by a blocker ring 122 positioned within the hollow interior 92 of the tubular main body 90 of traveler 88. The blocker ring 122 has an inner diameter smaller than an outer diameter of the end member 74 of pusher 70, such that the distal advancement of the pusher 70 through the hollow interior 92 of traveler 88 is limited. That is, the pusher 70 may advance distally through the traveler 88 until the end member 74 comes into contact with a proximal end / surface of the blocker ring 122, with the end member 74 then engaging the blocker ring 122 to prohibit further distal advancement of the pusher 70.

[0073] According to aspects of the disclosure, the drug delivery device 10 may be partially disassembled after completion of the second injector movement and dispensing of the medicament from the pre-filled syringe 14. Specifically, the distal housing portion 18 may be disassembled from the proximal housing portion 20, such as by threading the distal housing portion 18 off from the dose ring 48. With the distal housing portion 18 disassembled from the proximal housing portion 20, the emptied pre-filled syringe 14 may be removed (i.e., pulled out distally) from the auto-injector 12 and the auto-injector 12 may be reset in preparation for use again in a later injection.

[0074] In some embodiments, and as shown in FIG. 8, the distal housing portion 18 may be used as a tool for resetting the auto-injector 12. To do so, the orientation of the distal housing portion 18 is reversed and the distal end 22 of the distal housing portion 18 is used as a pushing tool for actuating the traveler 88 and pusher 70 back to their initial / pre-inj ection positions. With the orientation of the distal housing portion 18 reversed, the distal end 22 thereof is inserted through the open distal end 26 of the proximal housing portion 20 and brought into contact with the end member 74 of pusher 70. The distal housing portion 18 is then pushed proximally against the end member 74, causing the pusher 70 to move proximally back through proximal housing portion 20. As the pusher 70 is moved proximally back through proximal housing portion 20, the spring 86 is also caused to compress from its extended / non-loaded position back toward its compressed / loaded position.

[0075] Upon the pusher 70 being moved back proximally to a location where the retaining ring 84 contacts the inner lip 104 of traveler 88, a pushing force from the distal housing member 18 is then transferred / applied to the traveler 88 (via pusher 70), causing the traveler 88 to then move proximally back through proximal housing portion 20 - with the pusher 70 also continuing to be moved proximally back. As the traveler 88 and pusher 70 move proximally back through proximal housing portion 20, the spring 86 continues to further compress back toward its compressed / loaded position.

[0076] As the traveler 88 approaches its initial / pre-inj ection location, the trigger arms 34 can be actuated to displace the hooked latch ends 38 thereof radially outward, so that the traveler 88 can be moved back completely to its initial / pre-injection location. With the traveler 88 back in its initial / pre-injection position, the trigger arms 34 may then be released, such that the hooked latch ends 38 thereof move radially inward and back through the hook openings 42 in proximal housing portion 20 and engage a distal surface of the annular flange 98 of traveler 88 - such that the traveler 88 is locked in position. With the traveler 88 in its locked position, a final distal force may be applied to distal housing portion 18 that causes the retaining ring 84 on end member 74 to move past the inner lip 104 of annular flange 98 and to the proximal side of the inner lip 104. Following this final displacement of the pusher 70, the distal housing portion 18 may be withdrawn from the interior of proximal housing portion 20, thereby allowing deflectable arms 108 of traveler 88 to be positioned in their radially inward biased position, such that the deflectable arms 108 make contact with the distal end surface 76 of end member 74 and function as a support that prevents distal movement of the pusher 70.

[0077] With the auto-injector reset as described above, a new pre-filled syringe 14 may be loaded into auto-injector 12 and the distal housing portion 18 secured to the proximal housing portion 20 via dose ring 48. The drug delivery device 10 is thus prepared for use in another injection at a desired time. In some embodiments, the trigger lock 44 of auto-injector may be positioned (i.e., rotated) to a position that prevents accidental actuation of the auto-injector 12, thereby ensuring safe storage of the drug delivery device 10.

[0078] While embodiments of the drug delivery device 10 and auto-injector 12 have been shown and described above, it is recognized that features and / or components thereof may vary in construction without departing from the scope of the disclosure. As one example, trigger member 32 may be provided as an on / off latch (rather than trigger arms 34) that blocks / releases the motion of penetration and injection driven by the spring 86. As another example, the slide ribs 120 and deflectable arms 108 may be replaced by a spline slot formed in main body 90 of traveler 88 and a spline rib on an inner surface of the proximal housing portion 20, with thespline slot and spline rib interacting automatically achieve the first and second injection movements.

[0079] Beneficially, embodiments of the disclosure thus provide a reusable auto-injector for drug delivery. The auto-injector includes a single spring that drives the auto-injection to interact with the pre-filled syringe to facilitate both a needle penetration and a dispensing of solution from the syringe. The needle penetration and dispensing steps are automatically performed in sequential fashion upon activation of the auto-injector. Accordingly, both the structure and operation of the auto-injector is simplified as compared to other known autoinjectors, reducing manufacturing costs of the auto-injector and making use of the auto-injector more user friendly.

[0080] 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 housing comprising a distal housing portion and a proximal housing portion, the housing configured to receive a pre-filled syringe therein that includes a barrel, a plunger movable within the barrel, and a needle; an elongated pusher positioned within the proximal housing portion and movable axially relative thereto, the pusher comprising an end member at a distal end thereof; a spring positioned on the pusher and extending between a proximal end of the proximal housing portion and the end member, the spring actuatable between a loaded state and an unloaded state; a traveler positioned within the housing, distal to the pusher, and movable axially relative to the housing, the traveler defining a hollow interior; a trigger member actuatable between a locked position and an unlocked position, with the trigger member engaging the traveler when in the locked position and disengaging the traveler when in the unlocked position; wherein, upon the trigger member being actuated from the locked position to the unlocked position, the spring transitions from the loaded state to the unloaded state to: implement a first injector movement where the spring drives the pusher distally, with the pusher moving the traveler distally through the housing and the traveler, in turn, advancing the needle of the pre-filled syringe out distally from the housing; and implement a second injector movement upon the needle advancing out distally from the housing, where the spring drives the pusher distally through the hollow interior of the traveler, with the pusher forcing the plunger of the pre-filled syringe further into the barrel, to dispense a solution out from the pre-filled syringe.

2. The reusable auto-injector of claim 1, wherein the traveler comprises: a tubular main body defining the hollow interior; an annular flange formed circumferentially on the main body at a proximal end thereof and extending radially outward therefrom, the proximal flange and the end member having an interference therebetween; and a pair of deflectable arms formed on the main body that are deflectable radially outward relative to the main body.

3. The auto-injector of claim 2, further comprising a dose ring positioned within the housing, between the distal housing portion and the proximal housing portion, the dose ring comprising a tubular structure having an inner diameter greater than an outer diameter of the cylindrical main body and less than an outer diameter of the proximal flange, such that a distal movement of the traveler through the housing is limited by the dose ring.

4. The auto-injector of claim 3, wherein the distal housing portion and the proximal housing portion are separate members, and wherein the dose ring joins the distal housing portion and the proximal housing portion.

5. The auto-injector of claim 4, wherein the dose ring comprises a threaded tubular structure that engages each of the distal housing portion and the proximal housing portion via a threaded engagement.

6. The auto-injector of claim 5, wherein a position of the distal housing portion relative to the proximal housing portion is controllable based on a positioning of the distal housing portion and / or the proximal housing portion on the dose ring, via the threaded engagement therebetween.

7. The auto-injector of claim 3, wherein with the trigger member in the locked position, the pair of deflectable arms are in a radially inward position, such that the pair of deflectable arms engage a distal end surface of the end member.

8. The auto-injector of claim 7, wherein with the pair of deflectable arms in the radially inward position, the distal end surface of the end member is separated from a proximal end of the plunger.

9. The auto-injector of claim 7, wherein the proximal housing portion comprises an inner surface including a pair of slide ribs formed thereon that extend axially along the inner surface and protrude radially inward, the pair of slide ribs engaging the pair of deflectable arms and preventing deflection thereof radially outward relative to the main body, so as to retain the pair of deflectable arms in the radially inward position.

10. The auto-injector of claim 9, wherein the slide ribs extend distally along the inner surface from a first longitudinal location to a second longitudinal location, the second longitudinal location adjacent a proximal edge of the dose ring.

11. The auto-injector of claim 10, wherein with the trigger member in the unlocked position and as part of the first injector movement, the spring pushes the end member distally against a proximal end surface of the pair of deflectable arms when in the radially inward position, to advance the traveler distally through the housing.

12. The auto-injector of claim 11, wherein as part of the first injector movement, the dose ring limits the distal advancement of the traveler, with the annular flange engaging the dose ring to stop distal advancement of the traveler, thereby controlling a penetration depth of the needle.

13. The auto-injector of claim 9, wherein with the trigger member in the unlocked position and as part of the second injector movement, the pair of deflectable arms are in a radially outward position after having moved distal to the slide ribs, such that the pair of deflectable arms disengage from the distal end surface of the end member, enabling the pusher to advance distally through the traveler and push the plunger of the pre-filled syringe further into the barrel.

14. The auto-injector of claim 2, further comprising a blocker ring positioned within the hollow interior of the traveler, at a location between a distal end and a proximal end of the traveler, and wherein the blocker ring has an inner diameter smaller than an outer diameter of the end member.

15. The auto-injector of claim 14, wherein as part of the second injector movement, the pusher advances distally through the traveler until coming into contact with a proximal end of the blocker ring, with the end member engaging the blocker ring to stop distal advancement of the pusher.

16. The auto-injector of claim 2, wherein the trigger member comprises a pair of trigger arms joined to the proximal housing portion and formed on opposing sides thereof, each of the pair of trigger arms comprising a latch end that engages the proximal flangeand a finger-press end 40 engageable by a user, the finger press end being depressible inward to release the latch end from engagement with the proximal flange.

17. The auto-injector of claim 16, further comprising a trigger lock positionable on the proximal housing portion, the trigger lock comprising a plurality of locking arms that selectively engage the pair of trigger arms to prevent depression of the finger press end thereof.

18. The auto-injector of claim 17, wherein the trigger lock is rotatable about the proximal housing portion to selectively engage and disengage the plurality of locking arms with the pair of trigger arms.

19. The auto-injector of claim 2, wherein the end member comprises an elastomeric retaining ring positioned circumferentially about the end member, the retaining ring providing circumferential interference with the proximal flange.

20. A method of operating the auto-injector of claim 1, the method comprising: actuating the trigger member from the locked position to the unlocked position to release the traveler from engagement with the proximal housing portion, responsive to which the auto-injector automatically implements the first injector movement and the second injector movement in succession; wherein in implementing the first injector movement, the spring drives the pusher distally, with the pusher moving the traveler distally through the housing and the traveler, in turn, advancing the needle of the pre-filled syringe out distally from the housing; and wherein in implementing the second injector movement, the spring drives the pusher distally through the hollow interior of the traveler, with the pusher forcing the plunger of the pre-filled syringe further into the barrel, to dispense a solution out from the pre-filled syringe.

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