Injectors and drive systems for auto-injectors with interlock mechanisms

Abstract

Injectors and drive modules for injectors are provided, for delivering an agent from an injector module including an agent chamber and a piston. The drive module includes a drive housing including first and second ends, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet adjacent the actuator pin; an actuator configured to move the opener mechanism to cause the actuator pin to open the outlet and release the gas within the canister to flow from the first chamber into the second chamber, a plunger within the second chamber such that the gas causes the plunger to move, the plunger configured to advance the piston to deliver the agent; and a locking mechanism for preventing the actuator from moving until the locking mechanism is released.

Description

INJECTORS AND DRIVE SYSTEMS FOR AUTO-INJECTORS WITH INTERLOCK MECHANISMS RELATED APPLICATION DATA

[0001] The present application claims benefit of co-pending U.S. provisional application Serial No. 63 / 568,287, filed March 21, 2024, the entire disclosure of which is expressly incorporated by reference herein. The present application is related to U.S. Patent Nos. 10,716,892, 10,912,883, and 11,071,824, and U.S. Publication No. 2024 / 0033434, the entire disclosures of which are expressly incorporated by reference herein. TECHNICAL FIELD

[0002] The present application relates generally to devices and methods for delivering agents into a subject’s body and, more particularly, to injectors and / or gas- powered drive systems for injector devices, and to methods for making and using such devices. BACKGROUND

[0003] There are many applications involving delivery of a medicament or other agent subcutaneously, intramuscularly, or otherwise into a patient’s body. For example, auto-injectors are available that include a predetermined dose of the agent that may be delivered automatically into the patient’s body, e.g., after placement against the patient’s skin and activation. Generally, such auto-injectors are spring-loaded syringes that are activated to release the spring, which generates sufficient force to penetrate the skin with a needle and deliver the dose within the syringe. For viscous fluids, the forces required to develop fluid flow can be higher than those that spring-powered systems can provide. When springs can be used, they must generate a relatively high force that requires springs of high mass. Consequently, such auto-injectors may make substantial noise, create pressure spikes in the syringe leading to glass breakage, vibrate, and / or may drive the needle forcefully into the patient’s skin, which may cause pain and / or may startle the user, particularly when the patient is administering the injection themselves.

[0004] Components of gas-powered auto-injectors can experience external forces or acceleration acting on the device, e.g., during assembly, shipping and handling, prior to useractivation. These forces can cause movement on both external and internal components of the device leading to unintended device activation.

[0005] Therefore, improved devices and methods for delivering agents into a patient’s body would be useful. SUMMARY

[0006] The present application relates generally to devices and methods for delivering agents into a subject’s body and, more particularly, to injectors and / or gas- powered drive systems for injector devices, e.g., that provide end-of-dose indications to a user, and to methods for making and using such devices.

[0007] As explained above, components of gas-powered auto-injectors can experience external forces or acceleration of the device, e.g., during assembly, shipping and handling, or otherwise prior to user activation. These forces can cause movement on both external and internal component of the device leading to unintended device activation. The devices herein may reduce the risk of unintended device activation by introducing a locking mechanism or system that can only be disabled by the user following the intended activation sequence. Such interlock mechanisms may eliminate the possibility of an unwanted change of state, which includes but is not limited to displacement, deflection, deformation or destruction, of a trigger component or assembly without active control from the user.

[0008] In accordance with one example, a drive module is provided for delivering one or more agents into a patient’s body from an injector module comprising an agent chamber containing one or more agents and a piston, the drive module including a drive housing including a first end and a second end, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; a plunger slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber; and alocking mechanism for preventing the actuator from moving until the locking mechanism is released.

[0009] In one example, the opener mechanism includes a release cap carrying the actuator pin and the actuator includes an activation cap adjacent the second end of the drive housing such that a contact surface is disposed distal to the second end and an activation cap extension extends proximally around the drive housing; and a spacer adjacent the drive housing including a distal end adjacent a proximal end of the activation cap extension and a proximal end adjacent the release cap; the activation cap movable axially relative to the outer housing such that, when the contact surface of the activation cap is pressed against a subject’s skin, the activation cap is configured to move proximally to direct the spacer proximally, the spacer consequently directing the release cap proximally to release the actuator pin, thereby causing the actuator pin to open the outlet to release the gas into the first chamber and into the second chamber such that the gas advances the plunger to direct the piston distally to deliver the one or more agents through the needle, and wherein the locking mechanism includes one or more locking features on the activation cap to prevent axial movement of the activation cap until the features are disengaged.

[0010] In accordance with another example, a device is provided for delivering one or more agents into a patient’s body that includes an injector module comprising an injector housing carrying an agent chamber containing one or more agents and a piston slidably disposed within the agent chamber. The device also includes a drive module including a drive housing including a first end and a second end coupled to the injector module, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; a plunger slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber; and a locking mechanism for preventing the actuator from moving until the locking mechanism is released.

[0011] In one example, the opener mechanism includes a release cap carrying the actuator pin and the actuator includes an activation cap adjacent the second end of the drive housing such that a contact surface is disposed distal to the second end and an activation cap extension extends proximally around the drive housing; and a spacer adjacent the drive housing including a distal end adjacent a proximal end of the activation cap extension and a proximal end adjacent the release cap; the activation cap movable axially relative to the outer housing such that, when the contact surface of the activation cap is pressed against a subject’s skin, the activation cap is configured to move proximally to direct the spacer proximally, the spacer consequently directing the release cap proximally to release the actuator pin, thereby causing the actuator pin to open the outlet to release the gas into the first chamber and into the second chamber such that the gas advances the plunger to direct the piston distally to deliver the one or more agents through the needle, and wherein the locking mechanism includes one or more locking features on the activation cap to prevent axial movement of the activation cap until the features are disengaged.

[0012] In accordance with still another example, an injector device is provided that includes an injector module including an injector housing comprising a distal end and a proximal end; a syringe within the injector housing comprising an agent chamber containing one or more agents, a needle extending from the syringe adjacent the distal end, and a piston within the agent chamber; and an activation cap comprising a contact surface disposed distal to the distal end of the injector housing. The injector device also includes a drive module including a drive housing including a first end and a second end connectable to the proximal end of the injector housing, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; a spacer within the drive housing operatively coupled to the activation cap and the opener mechanism configured to move the opener mechanism when the activation cap is directed proximally when the contact surface is pressed against a patient’s skin to insert the needle, thereby causing the actuator pin to open the outlet and release the gas within the canister to flow from the first chamber into the second chamber; and a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger coupled to the piston to advance the piston to deliver the one or more agents from the agent chamber through the needle. The injector device alsoincludes a locking mechanism including one or more features on the second end of the drive housing coupled to one or more corresponding features on the spacer to prevent the spacer from moving; and one or more features on the proximal end of the injector housing configured to release the one or more features on the second end of the drive housing when the drive housing and injector are assembled together, thereby releasing the spacer such that the spacer is free to move when the actuator cap moves proximally.

[0013] In accordance with yet another example, an injector device is provided that includes an outer housing comprising a proximal end and a distal end; and an injector module including an agent chamber within the outer housing adjacent the distal end containing one or more agents, and a piston; an activation cap within the outer housing comprising a contact surface disposed distal to the distal end; and a safety cap coupled to the distal end covering the activation cap. The injector device also includes a drive module including a drive housing including a first end and a second end coupled to the injector module, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; and a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber. The injector device also includes a locking mechanism on one or both of the safety cap and the activation cap preventing axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing. For example, the locking mechanism may include a tab or finger on the distal end of the outer housing adjacent an outer surface of the activation cap; and a rib or ramped feature on the safety cap that directs the tab or finger radially inwardly when the safety cap is coupled to the distal end of the outer housing such that the tab or finger engages the outer surface of the activation cap to prevent axial movement of the activation cap. Optionally, the injector device may include a track coupled between the safety cap and the distal end of the outer housing configured such that the safety cap is rotatable to slide along the track to allow removal of the safety cap fromthe distal end, wherein rotation of the safety cap releases the locking mechanism, thereby allowing axial movement of the activation cap.

[0014] In accordance with another example, an injector module is provided for an injector device that includes an outer housing comprising a proximal end and a distal end; an agent chamber within the outer housing adjacent the distal end containing one or more agents, a needle extending from the agent chamber adjacent the distal end, and a piston within the agent chamber; an activation cap within the outer housing comprising a contact surface disposed distal to the needle; a safety cap coupled to the distal end covering the activation cap; a locking mechanism on one or both of the safety cap and the activation cap preventing axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing; and a track coupled between the safety cap and the distal end of the outer housing configured such that the safety cap is rotatable to slide along the track to allow removal of the safety cap from the distal end, wherein rotation of the safety cap releases the locking mechanism, thereby allowing axial movement of the activation cap, the activation cap configured to be coupled to an actuator of a drive module such that, when the activation cap is released and moves proximally, the activation cap activates the drive module to advance the piston and deliver the one or more agents from the agent chamber.

[0015] In accordance with still another example, an injector module is provided for an injector device that includes an outer housing comprising a proximal end and a distal end; an agent chamber within the outer housing adjacent the distal end containing one or more agents, a needle extending from the agent chamber adjacent the distal end, and a piston within the agent chamber; an activation cap within the outer housing comprising a contact surface disposed distal to the needle; a safety cap coupled to the distal end covering the activation cap; and a locking mechanism including a tab or finger on the distal end of the outer housing adjacent an outer surface of the activation cap; and a rib or ramped feature on the safety cap that directs the tab or finger radially inwardly when the safety cap is coupled to the distal end of the outer housing such that the tab or finger engages the outer surface of the activation cap to prevent axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing.

[0016] The devices herein may include any of the actuators disclosed in the patents incorporated by reference herein. For example, an actuation sleeve may be provided that is retracted when the needle is inserted into a patient’s skin, thereby actuating the opener mechanism to release the gas. Alternatively, a screw, lever, button, or other actuator maybe provided on the drive module that may be manually activated by a user to actuate the opener mechanism to release the gas.

[0017] Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] It is believed the present invention will be better understood from the following description of certain examples taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements and in which:

[0019] FIG. 1 is a perspective view of an exemplary auto-injector device including a front and rear housing, and a safety cap.

[0020] FIGS. 2A and 2B are longitudinal cross-sections of an exemplary auto- injector device showing internal components of the device including a syringe carrying one or more agents.

[0021] FIGS. 3A and 3B are details of the distal end of the device of FIGS. 2A and 2B before use, showing a safety cap covering an activation cap and needle of the device.

[0022] FIGS. 4A-4C are cross-sections of the device of FIGS. 2A and 2B, showing activation of the device when the activation cap is displaced proximally when the device is pressed against a subject’s skin to puncture the skin with the needle, the activation cap causing a spacer and release cap to also displace proximally to release a carriage carrying an opener pin, causing the opener pin to advance distally to open a gas canister to release pressurized gas into a flow path within the device.

[0023] FIGS. 5A-5C are details of the proximal end of the device as shown in FIGS. 4A-4C, respectively.

[0024] FIGS. 6A and 6B are cross-sections of the device of FIGS. 2A and 2B after the pressurized gas is released, showing the pressurized gas advancing a plunger within the device to deliver one or more agents within the syringe through the needle, and advancing the activation cap when the needle is withdrawn from the subject’s skin.

[0025] FIG. 6C is a detail of the device as shown in FIG. 6B, showing a tab locking the activation cap after being advanced.

[0026] FIGS. 7A and 7B are cross-sectional details of a proximal end of an injector device identifying components of an opener mechanism that may release due to externalforces or acceleration acting on the device before use, which may accidentally activate the device.

[0027] FIGS. 8A and 8B are cross-sections of an injector device showing user interface components of the device that may move due to external forces or acceleration acting on the device before use, which may accidentally activate the device.

[0028] FIG. 9A is a partial cross-sectional side view of an exemplary injector device including an interlock mechanism.

[0029] FIG. 9B is a side view of an activation cap, cylinder spacer, and release cap that may be included in the injector device of FIG. 9A.

[0030] FIG. 9C is a perspective detail of a proximal end of the injector device of FIG. 9A with an outer housing transparent to allow identification of internal components.

[0031] FIG. 9D is a cross-sectional view of the proximal end of the injector device of FIG. 9A showing release of the interlock mechanism.

[0032] FIG. 10A is a partial cross-sectional side view of another exemplary injector device including one or more interlock mechanisms.

[0033] FIG. 10B is a side view of an activation cap, cylinder spacer, and release cap that may be included in the injector device of FIG. 10A.

[0034] FIG. 10C is a cross-sectional detail of the injector device of FIG. 10A showing an interlock mechanism between a safety cap and an activation cap of the device.

[0035] FIGS. 10D and 10E are details of the injector device of FIG. 10A showing an interlock mechanism between a spacer and outer housing of the injector.

[0036] FIGS. 10F and 10G are perspective details showing disengaging the interlock mechanism of the device of FIGS. 10A-10C by rotating the safety cap.

[0037] FIGS. 11A and 11B are partial cross-sectional views of a distal end of another injector device including an interlock mechanism between a safety cap and an activation cap of the device.

[0038] FIG. 11C is a perspective view of the injector device of FIGS. 11A and 11B after removing the safety cap to expose the activation cap.

[0039] FIG. 11D is a perspective view of the safety cap of the injector device of FIGS. 11A and 11B.

[0040] FIGS. 11E and 11F are cross-sectional views of the safety cap and activation cap of the injector device of FIGS. 11A and 11B showing disengagement of the interlock mechanism.

[0041] The drawings are not intended to be limiting in any way, and it is contemplated that various examples of the invention may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention; it being understood, however, that this invention is not limited to the precise arrangements shown. DETAILED DESCRIPTION

[0042] Before the examples are described, it is to be understood that the invention is not limited to particular examples described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular examples only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0043] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0044] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, some potential and exemplary methods and materials are now described.

[0045] It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a compound” includes a plurality of suchcompounds and reference to “the polymer” includes reference to one or more polymers and equivalents thereof known to those skilled in the art, and so forth.

[0046] Certain ranges are presented herein with numerical values being preceded by the term “about.” The term “about” is used herein to provide literal support for the exact number that it precedes, as well as a number that is near to or approximately the number that the term precedes. In determining whether a number is near to or approximately a specifically recited number, the near or approximating unrecited number may be a number which, in the context in which it is presented, provides the substantial equivalent of the specifically recited number.

[0047] Turning to the drawings, FIG. 1 shows an example of an auto-injector device 6 that includes an outer housing 8 including a front housing 10 carrying a syringe 70 containing one or more agents within an agent chamber, and a rear housing 12 including a drive assembly for automatically delivering the agent(s) from the syringe 70 when the device 6 is activated. As shown, a safety cap 86 is provided on the front housing 10 to prevent premature activation of the device 6, which may be removed immediately before an injection, as described further elsewhere herein. One or more internal components of the device 6 may move axially, i.e., proximally and / or distally relative to the longitudinal axis 18 when the device 6 is activated, as described further elsewhere herein.

[0048] In one example, the syringe 70 may be a pre-filled syringe, e.g., formed from glass, plastic, and the like, filled with a predetermined volume of agent, e.g., corresponding to a single dose for a patient. Alternatively, the agent chamber and needle may be integrated into the front housing 10 if desired (not shown). In a further alternative, the syringe 70 (or integral agent chamber) may include a distal port (not shown) without a needle, such that a separate needle (also not shown) may be coupled to the port, e.g., using a Luer fitting, mating threads, and / or other cooperating connectors, immediately before an injection or otherwise as desired. As used herein, “agent” may include one or more flowable therapeutic and / or diagnostic compounds, medicaments, or materials, e.g., in liquid or gaseous form, in solution or suspension, and the like, such as viscous fluids.

[0049] Turning to FIGS 2A and 2B, an exemplary auto-injector device 6 is shown that includes an outer housing 8 including a front housing 10 carrying a syringe 70 containing one or more agents within an agent chamber 73, and a rear housing 12 including a drive assembly for automatically delivering the agent(s) from the syringe 70 when the device 6 is activated. As shown, a safety cap 86 is provided on the front housing 10 toprevent premature activation of the device 6, which may be removed immediately before an injection, as described further elsewhere herein. One or more internal components of the device 6 may move axially, i.e., proximally and / or distally relative to the longitudinal axis 18 when the device 6 is activated, as described further elsewhere herein.

[0050] In one example, the syringe 70 may be a pre-filled syringe, e.g., formed from glass, plastic, and the like, filled with a predetermined volume of agent, e.g., corresponding to a single dose for a patient. Alternatively, the agent chamber and needle may be integrated into the front housing 10 if desired (not shown). In a further alternative, the syringe 70 (or integral agent chamber) may include a distal port (not shown) without a needle, such that a separate needle (also not shown) may be coupled to the port, e.g., using a Luer fitting, mating threads, and / or other cooperating connectors, immediately before an injection or otherwise as desired. As used herein, “agent” may include one or more flowable therapeutic and / or diagnostic compounds, medicaments, or materials, e.g., in liquid or gaseous form, in solution or suspension, and the like, such as viscous fluids.

[0051] With continued reference to FIGS. 2A and 2B, the syringe 70 includes a barrel 72 containing the agent(s) within agent chamber 73, a needle 78 extending from a distal end 72a of the barrel 72, and a piston or stopper 74 slidable within a proximal end 72b of the barrel 72 for directing the agent(s) through the needle 78 into the subject’s body (not shown). The device 6 also includes a gas canister or other source of pressurized gas 40 to power the device 6, e.g., to advance a plunger 50 coupled to the piston 74 to deliver the agent(s). The device 6 also includes an activation cap 80 and an opener mechanism 60 for opening the canister 40 to release pressurized gas within the canister 40 into a set of chambers of the device 6. For example, an inner housing 20 may be mounted within the outer housing 8 that includes a first or proximal chamber 22, e.g., within which the gas canister 40 is mounted, and a second or distal chamber 24, e.g., in which the plunger 50 is slidably received.

[0052] Generally, the device 6 is configured such that, when a contact surface 84 of the activation cap 80 is pressed against a subject’s skin to insert the needle 78, the activation cap 80 retracts proximally into the outer housing 8 and automatically activates the opener mechanism 60 to release the pressurized gas from the canister 40 into the first and second chambers 22, 24, which generates a distal force to advance the plunger 50 to deliver the agent(s) from the syringe 70 into the subject. After the injection is completed and thedevice 6 is withdrawn away from the skin, the activation cap 80 may automatically advance to cover the needle 78.

[0053] For example, a spacer 30 may be provided that extends between the activation cap 80 and a release cap 34 of the opener mechanism 60, e.g., such that proximal movement of the activation cap 80 is translated by the spacer 30 to the direct the release cap 34 proximally within the rear housing 12, which releases a spring perch assembly or carriage 64 of the opener mechanism 60, as described further elsewhere herein. The spacer 30 may be biased distally, e.g., by spring 32, which may, in turn, bias the activation cap 80 distally after completing the injection, also as described further elsewhere herein.

[0054] Generally, the outer housing 8 includes a proximal end 8a, e.g., provided on the rear housing 12, an open distal end 8b, e.g., provided on the front housing 10, and an inner wall extending therebetween to enclose the interior of the device 6. The outer surface between the proximal and distal ends 8a, 8b may be sized and / or shaped to facilitate manipulation of the device 6, e.g., to facilitate placing and pressing the activation cap 80 against a subject’s skin to activate the device 6 and inject the agent(s). For example, the outer surface may have a generally cylindrical shape optionally including one or more textures or grip features to facilitate an operator (the subject themselves or a third party) holding the device 6 in one hand and pressing the activation cap 80 against the subject’s skin, as described further elsewhere herein. As shown, the proximal end 8a of the housing 8 may include a wall 8c enclosing the proximal end 8a and, optionally, one or more pockets or other features 8d for locking the release cap 34, as described further elsewhere herein.

[0055] The outer housing 8 may be formed from multiple, separate components, e.g., clamshell halves, e.g., formed from metal, such as stainless steel, aluminum, and the like, plastic, and / or composite material, by one or more of cold drawing, molding, casting, machining, and the like, that are substantially permanently attached together, e.g., by one or more of welding, soldering, fusing, bonding with adhesive, interference fit, and the like. As shown, the outer housing 8 is formed as separate forward and rear housings 10, 12, which may be assembled separately with respective internal components, and then coupled together, e.g., after loading a syringe 70 into the front housing 10.

[0056] For example, during manufacturing, the front housing 10 may be assembled with the activation cap 80 and safety cap 86, and a syringe 70 may be loaded into an interior of the front housing 10, e.g., during manufacturing or during assembly of the device 6 any time before performing an injection. Optionally, as shown in FIGS. 3A and 3B, the syringe70 may include a rigid needle shield 79, e.g. formed from conventional materials, that may be removably secured to the distal end 72a of the barrel 72 to protect the needle and prevent accidental sticks. The safety cap 86 may include features 86a that engage the needle shield 79 such that, when the safety cap 86 is removed, the needle shield 79 is also removed. For example, as shown, the proximal end of the safety cap 86 may include one or more fingers 86a that fit into one or more corresponding cutouts, recesses, or other features on the needle shield 79 when the syringe 70 is inserted into the front housing 10, thereby coupling the needle shield 79 to the safety cap 86, as described elsewhere herein.

[0057] The rear housing 12 may be assembled with the inner housing 20, the spacer 30, the release cap 34, the gas canister 40, the plunger 50, and the opener mechanism 60 (and any other incidental components), and the rear housing 12 may be coupled to the front housing 10 at any time. For example, during manufacturing, a syringe 70 may be loaded into the interior of the front housing 10, and the assembled rear housing 12 may be immediately coupled to the front housing 10. When the rear housing 12 is attached to the front housing 10, a distal end 54 of the plunger 50 may be coupled to the piston 74 within the syringe 70, e.g., such that distal movement of the plunger 50 is translated to the piston 74, as described further elsewhere herein.

[0058] As shown in FIGS. 2A and 2B, the outer housing 8 may include a mount 11, e.g., on one of the forward and rear housings 10, 12, for guiding and / or securing the syringe 70 during loading. Optionally, the proximal end 72b of the barrel 72 may include one or more flanges, e.g., a radial flange or a pair of opposing flanges, that may abut and / or be received within the mount 11 to secure the syringe 70 relative to the front housing 10. In addition or alternatively, one or more detents, ridges, or other features (not shown) may be provided on the front housing 10 for securing the syringe 70. Optionally, the front housing 10 may include one or more windows 10c in the sidewall, which may facilitate observing the syringe 70 during an injection, e.g., to allow visual confirmation when the piston 74 is fully advanced.

[0059] Optionally, the device 6 may include a syringe spacer or adapter 75 that may provide an interface between a distal end 54 of the plunger 50 and the piston 74, e.g., to provide connectors therebetween and / or ensure proper spacing such that the piston 74 is advanced in conjunction with the plunger 50. For example, different length spacers 75 may be provided to allow different length syringes to be loaded into the front housing 10 whileproperly positioning the needle 78 adjacent the distal end 8b of the outer housing 8 and allowing the plunger 50 to be properly coupled to the piston 74.

[0060] During manufacturing or assembly, a syringe 70 may be selected that may be inserted into the housing 8, e.g., through the opening in the distal end 8b and coupled to the distal end 16 of the drive assembly 12. A syringe spacer 75 may be selected and its distal end 75a may be coupled to the piston 74, e.g., by one or more cooperating threads, as shown, one or more detents or other connectors, and the like. The distal end 54 of the plunger 50 may be inserted into a recess 75b in the syringe spacer 75 when the rear housing 12 is coupled to the front housing 10. Optionally, the distal end 54 of the plunger 50 and the recess 75b may include cooperating locking features, e.g., one or more threads, detents, and the like (not shown) or the distal end 54 may simply be inserted into the recess 75b to coupled subsequent distal movement of the piston 74 to the plunger 50, as described further elsewhere herein.

[0061] Alternatively, the assembled housings 10, 12 may be packaged, stored, and / or otherwise prepared for subsequent assembly. For example, the housing 10, 12 may be shipped or otherwise provided to a manufacturer of the syringe 70, who may load the syringe 70 and couple the housings 10, 12 together to provide the finished device 6. In a further alternative, the assembled housings 10, 12 may be provided to a hospital, physician, or other medical professional, and final assembly may be completed immediately before performing an injection, which may allow a syringe including a specific agent to be loaded before an injection.

[0062] The proximal end 10a of the front housing 10 and the distal end 12b of the rear housing 12 may include one or more cooperating connectors (not shown) to couple the housings 10, 12 together to provide the fully-assembled device 6. For example, the housings 10, 12 may include one or mating threads, detents, and the like, which may permanently couple the housings 10, 12 together. Alternatively, the connectors may allow the housings 10, 12 to be subsequently separated, e.g., after performing an injection, to remove the syringe 70, e.g., to allow the device 6 to be cleaned and reused with a new syringe.

[0063] In addition or alternatively, the housings 10, 12 may be permanently attached together by one or more of an interference fit between the ends 10a, 12b, bonding with adhesive, fusing, sonic welding, and the like. In another alternative, the outer housing 8 may be formed as a single, integral component into which the components of the device 6may be assembled. In these alternatives or even with a two-part housing, the device 6 may be a single use device, which may be disposed of after a single injection.

[0064] In the example shown in FIGS. 2A and 2B, the inner housing 20 includes a proximal cylinder 20a including the first chamber 22 and a distal cylinder 20b including the second chamber 24. Each of the proximal and distal cylinders 20a, 20b may have an elongate cylindrical wall or other cross-sectional shape along their lengths. The proximal and distal cylinders 20a, 20b may be permanently attached together to provide the inner housing 20, e.g., by one or more of cooperating threads, as shown, detents or other connectors, force fit, bonding with adhesive, sonic welding, fusing, and the like. Alternatively, the inner housing 20 may be formed as a single, unitary structure including the first and second chambers 22, 24. The proximal and distal cylinders 20a, 20b may be formed from materials similar to or different from the outer housing 8.

[0065] The inner housing 20 may be mounted within the outer housing 8 such the inner housing 20 remains substantially stationary within the outer housing 8. Similarly, the gas canister 40 may be mounted within the inner housing 20, e.g., within the first chamber 22, such that the gas canister 40 also remains substantially stationary relative to the outer housing 8. For example, one or more struts, supports, or other structures (not shown) may be provided on the inner and / or outer housings 20, 8 to secure the inner housing 20 and / or the gas canister 40 relative to the outer housing 8.

[0066] In the example shown, the proximal cylinder 20a may include an annular wall surrounding the first chamber 22 that includes a uniform diameter first region 22a within which the gas canister 40 is mounted, and second and third regions 22b, 22c within which the carriage 64 is slidably mounted, as described further elsewhere herein. The distal cylinder 20b may have a length such that a distal end 21b of the distal cylinder 20b may abut the syringe 70 when the device 6 is assembled.

[0067] Optionally, the distal end 21b may include one or more features that contact the proximal end 72b of the syringe 70, e.g., an O-ring 20d secured on or around the distal end 21b formed from resilient and / or relatively flexible material. The O-ring 20d may prevent the distal end 21b from damaging the syringe 70, e.g., if the barrel 72 is made from glass.

[0068] With continued reference to FIGS. 2A and 2B, the canister 40 includes a body 42 including a first closed end 42a, a second outlet end 42b, and a cap 44 welded or otherwise attached to the outlet end 42b to provide an enclosed cavity 48 filled with a fluidcontaining pressurized gas, such as carbon dioxide or fluorocarbon gases, compressed to sufficient pressure to least partially liquefy the gas within the cavity 48. Alternatively, fluids containing gases such as argon, nitrogen, helium, or other combinations thereof that remain in gaseous form may be stored within the cavity 48. As described elsewhere herein, the pressurized fluid contained within the cavity 48 may be used to generate the forces to operate the device 6, e.g., to inject one or more agents from the syringe 70 into a subject’s body.

[0069] In one example, the body 42 and cap 44 may be formed from stainless steel or other desired or suitable metal, plastic, or composite material, e.g., formed by one or more of drawing, stamping, machining, casting, molding, and the like. For example, the body 42 may be deep drawn from sheet metal, e.g., a round sheet metal blank of Type 305 stainless steel, using one or more dies and punches (not shown), to form a main barrel region, the enclosed end 42a, an optional tapered shoulder region, and the outlet end 42b defining an opening to which the cap 44 is attached.

[0070] As shown, the canister 40 may be oriented with the outlet end 42b proximal to the enclosed end 42a, and the carriage 64 may be provided proximal to the outlet end 44. In the example shown, the cap 44 may be an enclosed cap including a septum, weakened region, or other outlet (not shown) that may be opened by the opener mechanism. In this example, the carriage 64 may include an opener pin 62 configured to puncture or preferentially tear the septum, as described elsewhere herein. Additional information regarding canisters that may be used and methods for making them may be found in U.S. Publication No. 2017 / 0258583, the entire disclosure of which is expressly incorporated by reference herein.

[0071] Alternatively, the cap 44 may include other closer mechanisms, such as a ball or other member (not shown) that may be biased or otherwise configured to close an outlet in the cap 44 yet may be directed away from the cap 44, e.g., into the canister 40, by the carriage 64 to open the outlet and release the pressurized gas within the cavity 48. In this alternative, the opener pin 62 may include a tapered tip (not shown) sized to enter the outlet and push the closure away from the outlet.

[0072] The plunger 50 may be an elongate rod or other member including a proximal end 52 that is slidably disposed within the second chamber 24, e.g., initially immediately adjacent the first chamber 22, and a distal end 54 coupled to the piston 74. The plunger 50 is movable from an initial or retracted position (e.g., shown in FIGS. 2A and 2B)to a final or extended position (e.g., shown in FIGS. 6A and 6B), e.g., wherein the distal end 54 extends from the second end 16 of the drive assembly 12 into the agent chamber 73 of the syringe 70.

[0073] A flange or other guide member 53 may be provided on the proximal end 52 of the plunger 50 that slidably engages a wall of the second chamber 24. Consequently, when pressurized gas enters the second chamber 24 (via the first chamber 22), the pressure generates a distal force to direct the plunger 50 distally from the initial position towards the extended position to advance the piston 74 and deliver the one or more agents from the agent chamber 73 through the needle 78 into the subject, as described further elsewhere herein.

[0074] Optionally, a wall, orifice, or intermediate passage (not shown) may be provided between the first and second chambers 22, 24. The intermediate passage may have a relatively small diameter to provide a restrictor to reduce pressure rise time within the second chamber 24. For example, the intermediate passage may i) slow down the transient flow of gas, slowing the rise of pressure imparted to the plunger 50, e.g., providing a soft-start to the injection, reducing / eliminating pressure shock waves in the fluid to be injected in the syringe and possibly reducing patient pain as the drug injection is gently initiated; and / or ii) slow down the steady state flow of gas, reducing the otherwise pressure imparted to the plunger 50, providing a limiting effect to the flow rate of the drug injected into the patient.

[0075] Optionally, as shown, the plunger 50 may also include a plunger chamber 56, e.g., extending from an open proximal end 52 of the plunger 50 to a closed distal end 54. The plunger chamber 56 may taper inwardly from the proximal end 52 to the distal end 54, as shown, or may have a uniform diameter or other cross-sectional shape along its length. Alternatively, the proximal end 52 of the plunger 50 may include a closed wall and / or the plunger 50 may be a solid rod between the proximal and distal ends 52, 54.

[0076] Optionally, the flange 53 on the proximal end 52 of the plunger 50 may include one or more passages (not shown) that extend between proximal and distal surfaces of the flange 53. For example, the flange 53 may include a plurality of circular or other enclosed passages spaced apart from one another around a circumference of the flange 53, each extending between the proximal and distal surfaces.

[0077] In this option, the flange 53 may be sized and / or shaped to slidably engage an inner wall of the second chamber 24, e.g., to allow the plunger 50 to move from theinitial to the extended position, but may not require O-rings or other seals. Instead, one or more O-rings or other seals may be provided within and / or adjacent the inner housing 20 to seal the first and second chambers 22, 24 and / or otherwise a flow path from the gas canister 40 to the plunger 50. For example, a first O-ring 58a may be provided between the inner housing 20 and the carriage 64, a second O-ring 58b may be provided between a distal end 21b of the inner housing 20 and the plunger 50, and / or a third O-ring 58c may be provided between the proximal and distal cylinders 10a, 10b, if provided as separate components secured together.

[0078] In one example, the plunger 50 includes a flange 53 formed as a cylindrical head having a larger outer diameter than the plunger 50, which may be integrally molded or otherwise formed with the plunger 50, or that is manufactured separately and permanently attached to the plunger 50, with one or more passages (not shown) extending between the proximal and distal surfaces of the flange 53. When the canister 40 is opened to release the pressurized gas, the initial volume that the gas must fill the first chamber 22 around the canister 40, the second chamber 24 around the plunger 50 and, optionally, the plunger chamber 56, which may result in an initial pressure drop as the gas fills the available volume. However, as the plunger 50 advances, the change in volume that the gas must fill increases only minimally (e.g., the volume the plunger 50 occupies within the second chamber 24 that is displaced out of the distal end 16 of drive assembly 12). Consequently, because the volume change is minimized, the resulting force applied by the pressure on the plunger 50 may remain substantially constant or reduce only slightly. Thus, the resulting force drop applied to the plunger 50 may be minimized, which may provide a more uniform delivery rate of the agent from the syringe 70. Additional information regarding plungers that may provide reduced pressure drop can be found in co-pending U.S. application, Serial Nos. 17 / 965,707, the entire disclosure of which is expressly incorporated by reference herein.

[0079] Optionally, the proximal end 52 of the plunger 50 may have a larger diameter or other cross-section than the distal end 54 of the plunger 50. For example, the outer diameter or cross-section may taper between the proximal and distal ends 52, 54 of the plunger 50. Such a tapered shape may increase the cross-sectional area of the plunger 50 as it advances from the initial position towards the extended position, which may minimize the change in the distal force applied to the syringe stopper due to volume change, which may be particularly useful for applications where consistent rates of delivery are desired. It willbe appreciated that any of these optional features related to the plunger 50 may be combined together or omitted, as desired.

[0080] Returning to FIGS. 2A and 2B, the opener mechanism 60 includes a release cap 34 and a spring perch assembly or carriage 64 slidably coupled to the rear housing 12, e.g., within the second and third regions 22b, 22c of the first chamber 24. The carriage 64 carries the opener pin 62, e.g., mounted along the axis 18 and oriented distally towards the cap 44. The carriage 64 and release cap 34 include one or more features that disengage when the release cap 34 is directed proximally (by the activation cap 80 and spacer 30), and the carriage 64 may be biased to move distally, when released, to direct the opener pin distally to open the outlet in the cap 44 of the canister 40.

[0081] For example, the rear housing 12 and the carriage 64 may include cooperating features that prevent the carriage 64 from moving until the device 6 is activated. For example, as best seen in FIGS. 5A-5C, the carriage 64 includes locking tabs or other features 64a on its proximal end that engage the proximal end 13a of the rear housing 12, and a flange 64b on its distal end slidable within the second region 22b of the first chamber 24. A puncture spring 66 is also provided within the second region 22b around the carriage 64, e.g., a coil spring provided in an initially compressed state between the rear housing 12 and the flange 64b. Consequently, the spring 66 biases the carriage 64 to move distally, but for the locking features 64a engaging the proximal end 13a of the rear housing 12.

[0082] The release cap 34 and carriage 64 include cooperating features that release the locking features 64a from the rear housing 12 when the device 6 is activated. For example, as shown in FIGS. 5A-5C, the release cap 34 includes a cylindrical body surrounding a portion of the rear housing 12, e.g., around the second and third regions 22b, 22c of the first chamber 24. The release cap 34 may also include an enclosed proximal end 34a proximal to the proximal end 13a of the rear housing 12, and a distal end 34b that includes one or more features to limit axial movement of the release cap 34. For example, one or more flanges on the distal end 34b may slide proximally along the inner surface of the outer housing 8, e.g., until they abut a ridge on the outer housing 8 to prevent further proximal movement of the release cap 34, as described further elsewhere herein.

[0083] As shown, a central hub 36 is provided on the proximal end 34a of the release cap 34 aligned along the axis 18 distally towards the opener pin 62. The carriage 64 includes a plurality of tabs or release fingers 65, e.g., arranged concentrically around the axis 18 such that the tabs 65 may slide along the hub 36 as the release cap 34 is directedproximally. Once the hub 36 moves proximally beyond the tabs 65, the tabs 65 are biased to move radially inwardly (towards the central axis 18), thereby directing the locking features 64a inwardly. Once the locking features 64a clear the proximal end 13a of the rear housing 12, e.g., as shown in FIG. 5C, the spring 66 may automatically direct the carriage 64 distally, thereby directing the opener pin 62 distally to penetrate the septum in the cap 44 of the canister 40 (or otherwise opening the outlet).

[0084] During use, the device 6 may be provided initially with the safety cap 86 attached to the distal end 8b of the housing 8, e.g., as shown in FIGS. 1-2B. Immediately before performing an injection, the safety cap 86 may be removed, e.g., by simply pulling the safety cap 86 distally away from the outer housing 8, to expose the contact surface 84 of activation cap 80, e.g., as shown in FIG. 4A. For example, as best seen in FIGS. 3A and 3B, the safety cap 86 may include inner and outer cylindrical members with the proximal end 86a of the inner member coupled to the needle shield 79 and a proximal end 86b of the outer member slidably received over the distal end 8b of the outer housing 8. Alternatively, the safety cap 86 and / or outer housing 8 may include one or more connectors, locks, and the like (not shown) that may be disengaged before removing the safety cap 86.

[0085] As described elsewhere herein, the safety cap 86 may prevent the activation cap 80 from being directed proximally, e.g., by preventing the activation cap 80 from being contacted. In addition or alternatively, the safety cap 86 may include features that engage the needle shield 79 such that, when the safety cap 86 is removed, the needle shield 79 is also removed. The safety cap 86 and needle shield 79 may prevent the needle 78 from being exposed from the housing 8 prior to use. Once the safety cap 86 and needle shield 79 are removed, the device 6 is ready to be used to perform an injection.

[0086] Turning to FIGS. 4A-4C, the contact surface 84 may be placed against a subject’s skin (not shown) and then the device 6 may be pressed against the skin to insert the needle 78, thereby causing the activation cap 80 to slide proximally from the initial position shown in FIG. 4A to the retracted position shown in FIG. 4B as the needle 78 enters the subject’s skin. As described further below, this action may activate the opener mechanism 60 to cause the opener pin 62 to open the outlet of the gas canister 40 to release pressurized gas into the first chamber 22, whereupon the pressurized has may advance the plunger 50 and, consequently, the piston 74 to deliver the agent(s) through the needle 78 into the subject.

[0087] For example, as shown in FIG. 4A, initially, the proximal end 82 of the activation cap 80 may abut or otherwise engage a distal end 30a of the spacer 30, and a proximal end 30b of the spacer 30 may abut or otherwise engage the distal end 34b of the release cap 34. Consequently, when the activation cap 80 is retracted proximally within the outer housing 8, its proximal end 82 pushes the distal end 30a of the spacer 30, thereby directing the spacer 30 proximally, and, in turn, the proximal end 30b of the spacer 30 pushes the distal end 34b of the release cap 34, thereby directing the release cap 34 proximally, e.g., until the proximal end 34a of the release cap 34 contacts the proximal end 8c of the outer housing 8.

[0088] As the activation cap 80, spacer 30, and release cap 34 move proximally, the inner housing 20 (and canister 40 within the first chamber 22) may remain substantially stationary. As can be seen in FIGS.4A and 4B, as the spacer 30 is directed proximally, the spring 32 may be compressed, e.g., between features on the distal end 30a of the spacer 30 and the inner housing 20, thereby biasing the spacer 30 subsequently to move distally. However, with the operator pressing the contact surface 84 of the activation cap 80 against the subject’s skin, the spacer 30 is unable to move distally.

[0089] Since the carriage 64 is secured relative to the inner housing 20 by the locking features 64a, the carriage 64 also remains substantially stationary, such that the release cap 34 moves proximally relative to the carriage 64 and the tabs 65 on the carriage 64 slide along the hub 36 on the release cap 34, as best seen in FIGS. 5A-5C. When the release cap 34 reaches its proximal-most position, e.g., shown in FIGS. 4C and 5C, the hub 36 has moved proximally beyond the ends of the tabs 65 and, given the inward bias of the tabs 65, the tabs 65 are released and automatically move inwardly. Given that the tabs 65 are coupled to the locking features 64a on the carriage 64, the inward movement of the tabs 65 causes the locking features 64a to move inwardly, thereby disengaging the locking features 64a from the proximal end 21a of the inner housing 20.

[0090] Due to the spring 66, the carriage 64 is then released and biased to move distally, thereby advancing the opener pin 62 distally to open the outlet of the canister 40, as shown in FIGS. 4C and 5C. The release cap 34 may include one or more tabs or other features 34c, e.g., corresponding to the pockets 8d in the outer housing 8, such that, when the release cap 34 reaches its proximal-most position, the tabs 34c are received in respective pockets 8d, as shown. Thus, the tabs 34c may prevent the release cap 34 from moving distally as the carriage 64 advances distally due to the spring 66.

[0091] When the carriage 64 moves distally, it causes the opener pin 62 to advance and penetrate the septum in the cap 44 (or otherwise open the outlet), thereby releasing the pressurized gas within the canister 40. The released pressurized gas then enters the first chamber 22, e.g., around the canister 40, and passes to the second chamber 24, thereby pressurizing the second chamber 24 to generate a distal force to direct the plunger 50 distally from the initial position towards its extended position to deliver the one or more agents from the syringe 70 through the needle 78 into the subject, e.g., as shown in FIG. 6A.

[0092] The operator may monitor the syringe 70 during the injection, e.g., via the window(s) 8c to confirm that the piston 74 has fully advanced distally within the barrel 72 to deliver the entire dose into the subject. Once the injection is completed, the device 6 may be directed away from the subject, thereby withdrawing the needle 78 from the subject’s skin. As the device 6 is directed away from the subject’s skin, the activation cap 80 is free to move distally and, due to the distal bias of the spring 32, the spacer 30 automatically advances distally, thereby directing the activation cap 80 distally to cover the needle 78 as it is withdrawn.

[0093] As best seen in FIG. 6C, as the spacer 30 advances distally, the proximal end 30b of the spacer may pass distally beyond features 34d on the distal end 34b of the release cap 34. For example, the features 34b may include one or more fingers or tabs that slide along the interior of the spacer 30 until the proximal end 30b passes distally, whereupon the tabs may resiliently move radially outwardly, e.g., such that the tabs 34d are located proximal to the proximal end 30b of the spacer 30, thereby preventing the spacer 30 from subsequently moving proximally. With the spacer 30 prevented from moving proximally, the activation cap 80 is unable to retract again, thereby locking the activation cap 80 extended over the needle 78 and preventing accidental exposure of the needle 78.

[0094] If the device 6 is a single-use device, the device 6 may then be disposed of. If the device is reusable, e.g., if the forward and rear housings 10, 12 are separable, the rear housing 12 may subsequently be separated from the front housing 10, and the syringe 70 may be removed. For a reusable device, one or more features may be provided within the device to release any residual pressure within the first and second chambers 22, 24. For example, as shown in FIGS. 6A and 6B, a gas valve and / or shaft member may be provided within the plunger 50, which may be manipulated to release the pressurized gas before removing decoupling the plunger 50 from the piston 74. The separate housings 10, 12 maythen be cleaned and / or sterilized and a new gas canister 40 may be loaded into the inner housing 20 before reassembling the device.

[0095] As explained above, components of gas-powered auto-injector devices may experience external forces or acceleration acting on of the devices, e.g., during assembly, shipping and / or handling, and / or other activities, prior to user activation. These forces may cause movement of one or both of external and internal components of the devices, which may result in unintended device activation. For example, FIGS. 7A and 7B are details of a proximal end of an injector device 6, e.g., generally similar to the device 6 shown in FIGS. 1-6. Similar to the device 6, the device 6 includes an opener mechanism 60 including a carriage 64 carrying an opener pin 62 and a release cap 34 that initially locks the carriage 64 until the device is activated, whereupon the carriage 64 is released to direct the opener pin 62 to open outlet of a gas canister 40, as described elsewhere herein.

[0096] In this example, the release cap 34 includes a central hub 36 and the carriage 64 includes a plurality of tabs or release fingers 65 that engage the central hub 36 until the release cap 34 is directed proximally, e.g., when displaced by the device’s actuator (not shown). However, before use, if the device experiences sudden forces or acceleration, the release cap 34 could accidentally move proximally, thereby disengaging the release fingers 65 and, consequently, the carriage 34 such that the opener pin 62 may open the canister 40 and release the pressurized gas prematurely.

[0097] Similarly, turning to FIGS. 8A and 8B, user interface components of an injector device, such as the device 6 of FIGS. 1-6, may free flow independently in the device before the removal or deactivation of a safety feature. For example, a safety cap 86, activation 80, and / or spacer 32 may accidentally displace if the device experiences sudden forces, which may activate the opener mechanism and release pressurized gas from a canister of the device. Thus, there is a risk that the device design may allow the user interfacial components to accidentally trigger the activation mechanism. Therefore, it may be beneficial to include an interlock mechanism on an injector device that locks the user interface components together and / or connects with safety features that restrict the motion of those components, which will eliminate the possibility of unwanted activation caused by user interface components. In one example, the interlocking may be accomplished by adhesive bonding or mechanical locking features.

[0098] Turning to FIGS. 9A-9D, exemplary user interface components of an injector device 106 are shown that include an interlock mechanism that prevents accidentalactivation of the device 106 until the interlock mechanism is released. Other components of the injector device 106 (e.g., a syringe, gas canister, and carriage) are omitted for clarity but the device 106 may include any of the components of the devices described previously. As shown in FIG. 9A, the interface components include an activation cap 180, a cylinder spacer 132, and a release cap 134, which are all received within an outer housing 108. The outer housing is omitted in FIG. 9B and shown transparent in FIG. 9C to facilitate identifying the interface components.

[0099] Similar to the device 6, the activation cap 180, spacer 132, and release cap 134 are operatively coupled together such that proximal movement of the activation cap 180 relative to the outer housing 108, e.g., when a contact surface 184 is pressed against a patient’s skin to insert a needle of the device into the patient (not shown), causes the spacer 132 and, consequently, the release cap 134 to move proximally. This motion may release a carriage (not shown), which may then automatically move axially to open a gas canister (also not shown) to release pressurized gas to perform an injection, generally similar to the device 6. [000100] Optionally, as shown in FIG. 9B, the activation cap 180 may be coupled to the spacer 132 by mechanical interlocking features, e.g., an axial extension 185 of the activation cap 180 may include a tab 185b or other connector that is received in a pocket 133 or other corresponding connector on a distal end 132b of the spacer 132. Optionally, the spacer 132 and release cap 134 may include similar mechanical interlocking connectors or features, if desired. In addition or alternatively, contact points between the activation cap 180, spacer 132, and / or release cap 134 may be attached together, e.g., by one or more of bonding with adhesive, welding, fusing, and the like. [000101] With particular reference to FIGS. 9C and 9D, in this example, the interlock mechanism includes one or more tabs 137 on the release cap 134 that are received in corresponding ribs or other features in the outer housing 108, which prevent proximal movement of the release cap 134. For example, as best seen in FIG. 9D, at least two tabs 137 may be provided on opposite sides of the release cap 134, which may be received within or otherwise engaged with the outer housing 108 to prevent axial movement of the release cap 134. Thus, if the device 106 experiences any sudden forces, the release cap 134 is unable to move, thereby prevent accidental release of the pressurized gas within the canister.[000102] As shown in FIG. 9D, during activation of the device 106, e.g., when the contact surface 184 is pressed against a patient’s skin to direct the activation cap 180 proximally, the spacer 132 may move proximally, as represented by “1” in FIG.9D. The tabs 137 of the interlock mechanism may be configured such that the spacer 132 causes the tabs 137 to bend inwardly, as represented by “2” in FIG. 9D, which disengages the tabs 137 from the outer housing 108, thereby releasing the interlock mechanism. [000103] As represented by “3” in FIG, 9D, continued proximal movement of the spacer 132 (due continued movement of the activation cap 180) causes the release cap 134 to move proximally. This action may release the carriage to open the gas canister (not shown), thereby releasing the pressurized gas to activate the device 106 to complete the injection, similar to other devices herein. [000104] Turning to FIGS. 10A-10G, another example of an injector device 206 is shown that includes one or more interlock mechanisms on user interface components that may prevent accidental activation of the device 206. As shown in FIG. 10A, the interface components include an activation cap 280, a cylinder spacer 232, and a release cap 234, which are all received within an outer housing 208. The outer housing is omitted in FIG. 10B to facilitate identifying the interface components. Similar to other devices herein, the injector device 206 may include additional components not, e.g., a gas canister, carriage carrying an opener pin, a plunger, the like. [000105] As best seen in FIG. 10B, the activation cap 280, spacer 232, and release cap 234 are operatively coupled together such that proximal movement of the activation cap 280 relative to the outer housing 208, e.g., when a contact surface 284 is pressed against a patient’s skin to insert a needle of the device into the patient (not shown), causes the spacer 232 and, consequently, the release cap 234 to move proximally. This motion may release a carriage (not shown), which may then automatically move axially to open a gas canister (also not shown) to release pressurized gas to perform an injection. [000106] Optionally, as shown, the activation cap 280 may be coupled to the spacer 232 by mechanical interlocking features, e.g., an axial extension 285 of the activation cap 280 may include a tab 285b or other connector that is received in a pocket 233 or other corresponding connector on a distal end 232b of the spacer 232. In addition or alternatively, contact points between the activation cap 280, spacer 232, and / or release cap 234 may be attached together, e.g., by one or more of bonding with adhesive, welding, fusing, and the like.[000107] As shown in FIGS.10A and 10C, the device 206 includes a safety cap 286 provided on a distal end of the outer housing 208, which may include interlocking features that prevent axial movement of the activation cap 280 until disengaged. For example, the safety cap 286 may include an extrusion or other feature 286a that engage ribs 280a on the activation cap 280 that prevent axial movement of the activation cap 280. It will be appreciated that other detents or connectors may be provided between the safety cap 286 and the activation cap 280, if desired. [000108] Turning to FIGS. 10F and 10G, the interlocking features may be disengaged by twisting the safety cap 286, e.g., such that the safety cap 286 rotates helically relative to the outer housing 208. For example, as shown in FIG. 10F, a helical groove 209 may be provided on the distal end 208b of the outer housing 208 and a tab or other feature 286c on the safety cap 286 may be slidably received in the groove 209, e.g., such that rotation of the safety cap 286 in a first direction, e.g., in a counterclockwise direction as represented by curved arrow A1, causes the feature 286b to slide helically along the groove 209 to direct the safety cap 286 distally as represented by the axial arrow A2 in FIG. 10F until the feature 286b exits the groove 209, thereby releasing the safety cap 286 from the distal end 208b of the housing 208 to allow removal of the safety cap 286 and expose the activation cap 280. This rotation may also disengage the interlocking features between the safety cap 286 and the activation cap 280 such that the activation cap 280 may be free to move axially, e.g., when the contact surface 284 is pressed against a patient’s skin. [000109] In addition or alternatively, an interlock mechanism may be provided between the spacer 232 and the outer housing 208, e.g., to prevent risk of undesired proximal movement of the spacer 232. For example, as best seen in FIG. 10D, one or more detents, fingers, or other locking features 212) may be provided on a rear housing 212 of the outer housing 208 that are received in corresponding pockets or recesses 232a in the spacer 232 that prevent proximal movement of the spacer 232. Although one locking finger 212a and recess 232a are shown in FIG. 10D, it will be appreciated that two may be provided, e.g., on opposite sides of the spacer 232 and rear housing 212, or more than two may be provided that are spaced apart around the circumference of the spacer 232 and rear housing 212. [000110] In one example, the injector device 206 may be provided with a separate injector and drive module, which may be assembled immediately before use. For example, the drive module may include the spacer 232, release cap 234, and other components, notshown, e.g., gas canister, carriage carrying an opener pin, and the like, received within rear housing 212. The rear housing 212 includes the one or more locking features 212a that are received in the corresponding recesses 232a in the spacer 232 to prevent proximal movement of the spacer 232. Thus, the interlocking feature(s) 212a, 232a may prevent the spacer 232 from moving proximally to direct the release cap 234 proximally, thereby preventing pressurized gas from being release prematurely. [000111] As shown in FIG. 10E, the injector module includes a forward housing 210 of the outer housing 208, e.g., into which a syringe or other agent container may be loaded before use, and carrying the activation cap 280 and safety cap 286. As shown, a proximal end of the forward housing 210 may include one or more ramped features 210a, which may be contact corresponding interlocking features 212a when the housing portions 210, 212 are assembled together. For example, when the proximal end of the forward housing 210 is directed against the distal end of the rear housing 212, the ramped feature 210a may slidably engage the corresponding locking feature(s) 212a on the rear housing 212, thereby directing the locking feature(s) 212a radially outward out of the recess(es) 232a in the spacer 232. Thus, the spacer 232 may be released such that the spacer 232 may subsequently move axially, e.g., may be directed proximally by the activation cap 280. [000112] Turning to FIGS. 11A-11F, another example of an injector device 306 is shown that includes an outer housing 308, an activation cap 380, and a safety cap 386. The device 306 may include other components, not shown, similar to other devices herein. Similarly to other devices herein, the safety cap 386 may be initially coupled to a distal end 308b of the outer housing 308, thereby covering the activation cap 380. For example, the safety cap 386 may include an outer annular portion 386a including a proximal collar 386b that may be slidably received over the distal end 308b of the outer housing 308. Thus, in this example, the safety cap 386 may simply be pulled distally, e.g., as represented by arrow A3 in FIG. 11F. [000113] The safety cap 386 and outer housing 308 may include an interlock mechanism, which may releasably engage the activation cap 380 to prevent axial movement of the activation cap 386 until the safety cap 386 is removed. For example, as shown, the distal end 308 of the outer housing 308 may include one or more tabs, fingers, cantilevered elements, and the like 309, which may be positioned adjacent an outer surface 381 of the activation cap 380. The safety cap 386 includes one or more ribs or ramped features 386cthat may interact with the tabs 309 when the safety cap 386 is positioned over the distal end 308b of the outer housing 308. [000114] For example, as best seen in FIG. 11D, a pair of internal ribs 386c may be provided on an inner surface of collar 386b of the safety cap 386, and the outer housing 308 may include a corresponding pair of tabs 309 on opposite sides of the distal end 308b. It will be appreciated that only one or more than two ribs and tabs may be provided, as desired. As best seen in FIG. 11E, when the collar 386b of the safety cap 386 is positioned over the distal end 308b of the outer housing 308, the ribs 386c may slidably engage the tabs 309 on the outer housing 308, thereby directing the tabs 309 radially inwardly into contact with the outer surface 381 of the activation cap 380. [000115] For example, as shown, each rib 386c may include a tapered or ramped proximal edge such that, as the collar 386b is advanced over the distal end 308b of the outer housing 308, the tapered edge may slide over the tab 309, thereby deflecting the tab 309 radially inward against the outer surface 381 of the activation cap 380. The tabs may be biased to return radially outwardly when the safety cap 386 is removed. For example, as shown in FIG. 11F, as the safety cap 386 is removed distally from the outer housing 308, the collar 386b may slide away from the tab 309, thereby releasing the tab 309 to resiliently return to its relaxed position away from the outer surface 381 of the activation cap 380. [000116] The frictional engagement of the inner surface of the tabs 309 against the outer surface 381 of the activation cap 380 may prevent the activation cap 380 from moving axially. Optionally, if desired, the outer surface 380 of the activation cap 380 may include features that further interlock with the tabs 309 when the tabs 309 are directed inwardly by the safety cap 386. For example, a recess (not shown) may be provided in the outer surface that receives a detent or other portion of a corresponding tab to prevent movement. [000117] Once the safety cap 386 is removed (and the tabs 309 disengaged from the activation cap 380), the device 306 may be used to perform an injection, e.g., by pressing the contact surface 384 of the activation cap 380 against a patient’s skin to insert a needle of the device 306, whereupon the activation cap 380 may move proximally to displace a spacer and / or release cap to open an outlet of a gas canister (not shown) to deliver one or more agents, similar to other devices herein. [000118] While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to theparticular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.

Claims

WE CLAIM:

1. A drive module for delivering one or more agents into a patient’s body from an injector module comprising an agent chamber containing one or more agents, an outlet, and a piston, the drive module comprising: a drive housing including a first end and a second end, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber; and a locking mechanism for preventing the actuator from moving until the locking mechanism is released.

2. The drive module of claim 1, wherein the opener mechanism comprises a release cap carrying the actuator pin and the actuator comprises: an activation cap adjacent the second end of the drive housing such that a contact surface is disposed distal to the second end and an activation cap extension extends proximally around the drive housing; and a spacer adjacent the drive housing comprising a distal end adjacent a proximal end of the activation cap extension and a proximal end adjacent the release cap; the activation cap movable axially relative to the outer housing such that, when the contact surface of the activation cap is pressed against a subject’s skin, the activation cap is configured to move proximally to direct the spacer proximally, the spacer consequently directing the release cap proximally to release the actuator pin, thereby causing the actuator pin to open the outlet to release the gas into the first chamber and into the second chambersuch that the gas advances the plunger to direct the piston distally to deliver the one or more agents, wherein the locking mechanism comprises one or more locking features on the activation cap to prevent axial movement of the activation cap until the features are disengaged.

3. The drive module of claim 2, wherein the locking features comprise tabs on the activation cap that engage features in the drive housing until disengaged.

4. The drive module of claim 3, wherein the activation cap is movable proximally relative to the drive housing to disengage the tabs from the features in the drive housing.

5. The drive module of claim 3, wherein the activation cap is configured to be initially moved proximally relative to the drive housing and then rotated to deflect the tabs to disengage the tabs from the features in the drive housing and release the actuator for subsequent activation.

6. The drive module of claim 2, wherein the locking mechanism comprises a safety cap covering a needle of the agent chamber and the locking mechanism comprises one or more features on the safety cap and the activation cap that prevent movement of the activation cap until the safety cap is removed.

7. The drive module of claim 6, wherein the one or more features comprise a tab on one of the safety cap and the activation cap and a helical track on the other of the safety cap and the activation cap, the tab received initially in the track to prevent movement of the activation cap, the safety cap rotatable relative to the drive housing to slide the tab along the track and remove the safety cap, thereby releasing the activation cap for subsequent activation.

8. The drive module of any one of claims 2-7, wherein the spacer is biased to advance distally such that, when the activation cap is released when the contact surface is directed away from the subject’s skin after delivering the one or more agents, the spacerdirects the activation cap distally to cover the needle, the spacer comprising one or more locking members for preventing subsequent proximal movement of the spacer and activation cap.

9. The drive module of claim 1, wherein the actuator comprises an actuator sleeve that is retracted when the injector housing is pressed against a patient’s skin to insert the needle, the actuator sleeve configured to release the opener mechanism to cause the actuator pin to open the outlet and release the gas.

10. The drive module of claim 1, wherein the actuator comprises a manual actuator on the drive module that may be manually activated by a user to actuate the opener mechanism to open the outlet and release the gas.

11. An injector device, comprising: a) an injector module comprising an agent chamber containing one or more agents and a piston; and b) a drive module comprising: a drive housing including a first end and a second end coupled to the injector module, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber; and a locking mechanism for preventing the actuator from moving until the locking mechanism is released.

12. The device of claim 11, wherein the opener mechanism comprises a release cap carrying the actuator pin and the actuator comprises: an activation cap adjacent the second end of the drive housing such that a contact surface is disposed distal to the second end and an activation cap extension extends proximally around the drive housing; and a spacer adjacent the drive housing comprising a distal end adjacent a proximal end of the activation cap extension and a proximal end adjacent the release cap; the activation cap movable axially relative to the outer housing such that, when the contact surface of the activation cap is pressed against a subject’s skin, the activation cap is configured to move proximally to direct the spacer proximally, the spacer consequently directing the release cap proximally to release the actuator pin, thereby causing the actuator pin to open the outlet to release the gas into the first chamber and into the second chamber such that the gas advances the plunger to direct the piston distally to deliver the one or more agents from the agent chamber, wherein the locking mechanism comprises one or more locking features on the activation cap to prevent axial movement of the activation cap until the features are disengaged.

13. The device of claim 12, wherein the locking features comprise tabs on the activation cap that engage features in the drive housing until disengaged.

14. The device of claim 13, wherein the activation cap is movable proximally relative to the drive housing to disengage the tabs from the features in the drive housing.

15. The device of claim 13, wherein the activation cap is configured to be initially moved proximally relative to the drive housing and then rotated to deflect the tabs to disengage the tabs from the features in the drive housing and release the actuator for subsequent activation.

16. The device of claim 12, wherein the locking mechanism comprises a safety cap covering a needle of the agent chamber and the locking mechanism comprises one ormore features on the safety cap and the activation cap that prevent movement of the activation cap until the safety cap is removed.

17. The device of claim 16, wherein the one or more features comprise a tab on one of the safety cap and the activation cap and a helical track on the other of the safety cap and the activation cap, the tab received initially in the track to prevent movement of the activation cap, the safety cap rotatable relative to the drive housing to slide the tab along the track and remove the safety cap, thereby releasing the activation cap for subsequent activation.

18. The device of any one of claims 12-17, wherein the spacer is biased to advance distally such that, when the activation cap is released when the contact surface is directed away from the subject’s skin after delivering the one or more agents, the spacer directs the activation cap distally to cover the needle, the spacer comprising one or more locking members for preventing subsequent proximal movement of the spacer and activation cap.

19. The device of claim 11, wherein the actuator comprises an actuator sleeve that is retracted when the injector housing is pressed against a patient’s skin to insert the needle, the actuator sleeve configured to release the opener mechanism to cause the actuator pin to open the outlet and release the gas.

20. The device of claim 11, wherein the actuator comprises a manual actuator on the drive module that may be manually activated by a user to actuate the opener mechanism to open the outlet and release the gas.

21. The device of claim 20, wherein the manual actuator comprises one of a screw, a button, and a lever.

22. The device of one of claims 12-17, further comprising an outer device housing carrying the drive housing and wherein the injector module comprises a syringe received within the outer device housing.

23. An injector device, comprising: a) an injector module comprising: an injector housing comprising a distal end and a proximal end; a syringe within the injector housing comprising an agent chamber containing one or more agents, a needle extending from the syringe adjacent the distal end, and a piston within the agent chamber; and an activation cap comprising a contact surface disposed distal to the distal end of the injector housing; and b) a drive module comprising: a drive housing including a first end and a second end connectable to the proximal end of the injector housing, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; a spacer within the drive housing operatively coupled to the activation cap and the opener mechanism configured to move the opener mechanism when the activation cap is directed proximally when the contact surface is pressed against a patient’s skin to insert the needle, thereby causing the actuator pin to open the outlet and release the gas within the canister to flow from the first chamber into the second chamber; a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger coupled to the piston to advance the piston to deliver the one or more agents from the agent chamber through the needle; and a locking mechanism comprising: one or more features on the second end of the drive housing coupled to one or more corresponding features on the spacer to prevent the spacer from moving; and one or more features on the proximal end of the injector housing configured to release the one or more features on the second end of the drive housing when the drive housing and injector are assembled together, thereby releasing the spacer such that the spacer is free to move when the actuator cap moves proximally.

24. The device of claim 23, wherein the one or more features on the second end of the drive housing comprise a tab, detent, or finger on the second end that is received in a corresponding recess in the spacer to couple the spacer to the drive housing to prevent axial movement of the spacer.

25. The device of claim 24, wherein the one or more features on the proximal end of the injector housing comprise a ramped feature that slidably engaged the tab, detent, or finger to direct the tab, detent, or finger out of the recess to release the spacer.

26. An injector device, comprising: a) an outer housing comprising a proximal end and a distal end; b) an injector module comprising: an agent chamber within the outer housing adjacent the distal end containing one or more agents, and a piston; an activation cap within the outer housing comprising a contact surface disposed distal to the distal end; and a safety cap coupled to the distal end covering the activation cap; and c) a drive module comprising: a drive housing including a first end and a second end coupled to the injector module, a first chamber adjacent the first end communicating with a second chamber adjacent the second end; an opener mechanism within the first chamber including an actuator pin; a canister containing pressurized gas including an outlet disposed adjacent the actuator pin; an actuator configured to move one of the opener mechanism and the canister to cause the actuator pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber; a plunger comprising a proximal end slidably disposed within the second chamber such that the gas entering the second chamber causes the plunger to move from an initial position to an extended position, the plunger configured to be coupled to the piston of the injector module to advance the piston of the injector module to deliver the one or more agents from the agent chamber; anda locking mechanism on one or both of the safety cap and the activation cap preventing axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing.

27. The device of claim 26, wherein the locking mechanism comprises: a tab or finger on the distal end of the outer housing adjacent an outer surface of the activation cap; and a rib or ramped feature on the safety cap that directs the tab or finger radially inwardly when the safety cap is coupled to the distal end of the outer housing such that the tab or finger engages the outer surface of the activation cap to prevent axial movement of the activation cap.

28. The device of claim 27, wherein the tab or finger is biased outwardly such that, when the safety cap is removed from the distal end of the outer housing, the tab or finger resiliently moves away from the outer surface to allow the activation cap to subsequently move axially.

29. The device of claim 27 or 28, wherein the tab or finger is pressed against the outer surface by the rib or ramped feature such that the tab or finger frictionally engages the outer surface to prevent movement of the activation cap.

30. The device of claim 26, further comprising a track coupled between the safety cap and the distal end of the outer housing configured such that the safety cap is rotatable to slide along the track to allow removal of the safety cap from the distal end, wherein rotation of the safety cap releases the locking mechanism, thereby allowing axial movement of the activation cap.

31. The device of claim 30, wherein the track comprises a helical groove in one of the safety cap and the distal end a tab slidable in the helical groove such that rotation of the safety cap causes the tab to slide along the helical groove to direct the safety cap distally until released from the distal end of the outer housing.

32. The device of any one of claims 26-31, wherein the actuator comprises a spacer within the outer housing and operatively coupled between the activation cap and the opener mechanism such that proximal movement of the activation cap directs the spacer proximally to release the opener mechanism to release the gas within the canister.

33. An injector module for an injector device, comprising: an outer housing comprising a proximal end and a distal end; an agent chamber within the outer housing adjacent the distal end containing one or more agents, a needle extending from the agent chamber adjacent the distal end, and a piston within the agent chamber; an activation cap within the outer housing comprising a contact surface disposed distal to the needle; a safety cap coupled to the distal end covering the activation cap; a locking mechanism on one or both of the safety cap and the activation cap preventing axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing; and a track coupled between the safety cap and the distal end of the outer housing configured such that the safety cap is rotatable to slide along the track to allow removal of the safety cap from the distal end, wherein rotation of the safety cap releases the locking mechanism, thereby allowing axial movement of the activation cap, the activation cap configured to be coupled to an actuator of a drive module such that, when the activation cap is released and moves proximally, the activation cap activates the drive module to advance the piston and deliver the one or more agents from the agent chamber.

34. The injector module of claim 33, wherein the track comprises a helical groove in one of the safety cap and the distal end a tab slidable in the helical groove such that rotation of the safety cap causes the tab to slide along the helical groove to direct the safety cap distally until released from the distal end of the outer housing.

35. An injector module for an injector device, comprising: an outer housing comprising a proximal end and a distal end;an agent chamber within the outer housing adjacent the distal end containing one or more agents, a needle extending from the agent chamber adjacent the distal end, and a piston within the agent chamber; an activation cap within the outer housing comprising a contact surface disposed distal to the needle; a safety cap coupled to the distal end covering the activation cap; and a locking mechanism comprising: a tab or finger on the distal end of the outer housing adjacent an outer surface of the activation cap; and a rib or ramped feature on the safety cap that directs the tab or finger radially inwardly when the safety cap is coupled to the distal end of the outer housing such that the tab or finger engages the outer surface of the activation cap to prevent axial movement of the activation cap until the safety cap is removed from the distal end of the outer housing.

36. The injector module of claim 35, wherein the tab or finger is biased outwardly such that, when the safety cap is removed from the distal end of the outer housing, the tab or finger resiliently moves away from the outer surface to allow the activation cap to subsequently move axially.

37. The injector module of claim 35 or 36, wherein the tab or finger is pressed against the outer surface by the rib or ramped feature such that the tab or finger frictionally engages the outer surface to prevent movement of the activation cap.

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