Injectors and drive systems for injectors with gas cylinders, and methods for making such injectors

Abstract

Drive modules and. auto-injectors are provided for delivering an agent into a patient's body. The injector includes an injector module including an agent chamber containing an agent and a piston, and a drive module including a drive housing including a first chamber therein. A plunger, which is coupled to the piston, is slidable within the drive housing from an initial position to an extended position. The drive housing includes an opener mechanism including an opener pin disposed adjacent a gas canister, and an actuator configured to open the canister with the opener pin to release the pressurized gas to advance the plunger, whereupon the plunger advances the piston to deliver the agent from the agent chamber. Improved methods for manufacturing and assembling such injectors is also provided, e.g., to support the gas canister and / or opener mechanism.

Description

INJECTORS AND DRIVE SYSTEMS FOR INJECTORS WITH GAS CYLINDERS, AND METHODS FOR MAKING SUCH INJECTORS RELATED APPLICATION DATA

[0001] The present application claims benefit of co-pending U.S. provisional application Serial No. 63 / 568,275, filed March 21, 2024, the entire disclosure of which is 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 auto-injectors and / or gas- powered drive systems for injection 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. Manual injectors are also available that allow a user to manually deliver a desired dose of the agent.

[0004] Generally, 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 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.

[0005] Gas-powered auto-injectors have also been developed, such as those disclosed in U.S. Patent Nos. 10,716,892, 10,912,883, and 11,071,824, the entire disclosures of which are expressly incorporated by reference herein. Gas-powered injectors include a gas canisteror container therein filled with pressurized gas that is used to power a plunger or other force- providing component to deliver one or more agents from the injector.

[0006] Therefore, improved devices and methods for delivering agents into a patient’s body, e.g., that are more compact than conventional injectors, would be useful. SUMMARY

[0007] 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 injection devices.

[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 adjacent the first end including an opener pin; a canister containing pressurized gas including an outlet disposed adjacent the opener pin; an actuator configured to move one of the opener mechanism and the canister to cause the opener 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 slidably disposed within the second chamber such that pressurized 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; wherein the drive housing comprises a bulkhead dividing the first and second chambers and configured to at least partially receive the canister.

[0009] 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 adjacent the first end including an opener pin; a canister containing pressurized gas including an outlet disposed adjacent the opener pin; an actuator configured to move one of the opener mechanism and the canister tocause the opener 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 slidably disposed within the second chamber such that pressurized 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; wherein the drive housing comprises a bulkhead dividing the first and second chambers and configured to at least partially receive the canister.

[0010] Any of the injector devices described 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 activating the opener mechanism to release the gas. Alternatively, a screw, lever, button, or other actuator may be provided on the drive module that may be manually activated by a user to actuate the opener mechanism to release the gas.

[0011] 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

[0012] 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:

[0013] FIG. 1 is a perspective view of an exemplary auto-injector device including a front and rear housing, and a safety cap.

[0014] 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.

[0015] 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.

[0016] 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 anopener pin, causing the opener pin to advance distally to open a gas canister to release pressurized gas into a flow path within the device.

[0017] FIGS. 5A-5C are details of the proximal end of the device as shown in FIGS. 4A-4C, respectively.

[0018] 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.

[0019] FIG. 6C is a detail of the device as shown in FIG. 6B, showing a tab locking the activation cap after being advanced.

[0020] FIG. 7 is a cross-sectional view of an example of a two-piece drive housing, which may be included in an injector, including proximal and distal housings securing a bulkhead therebetween.

[0021] FIG. 8 is a cross-sectional view of another example of a two-piece drive housing, which may be included in an injector, including an inner housing carrying a bulkhead received within an outer housing.

[0022] FIG. 9 is a cross-sectional view of yet another example of a two-piece drive housing, which may be included in an injector, including an inner housing carrying a bulkhead received within an outer housing.

[0023] FIG. 10 is a cross-sectional view of still another example of a two-piece drive housing, which may be included in an injector, including an inner housing carrying a bulkhead received within an outer housing.

[0024] FIG. 11 is a cross-sectional view of another example of a two-piece drive housing, which may be included in an injector, including proximal and distal housings together by a butt joint.

[0025] FIG. 12 is a cross-sectional view of another example of a two-piece drive housing, which may be included in an injector, including proximal and distal housings together by a threaded joint.

[0026] FIG. 13 is a cross-sectional view of another example of a two-piece drive housing, which may be included in an injector, including proximal and distal housings together by an overlap joint.

[0027] FIG. 14 is a cross-sectional view of an example of a one-piece drive housing, which may be included in an injector, including a bulkhead and seal gland assembly secured within the housing.

[0028] FIG. 15 is a cross-sectional view of another example of a one-piece drive housing, which may be included in an injector, including a bulkhead and seal gland assembly secured within the housing.

[0029] FIG. 16 is a cross-sectional view of yet another example of a one-piece drive housing, which may be included in an injector, including a bulkhead and seal gland assembly secured within the housing.

[0030] FIGS. 17A and 17B are cross-sectional view of still another example of a one-piece drive housing, which may be included in an injector, including a bulkhead and seal gland assembly secured within the housing.

[0031] 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

[0032] 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.

[0033] 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 rangesis 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.

[0034] 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.

[0035] 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 such compounds 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.

[0036] 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.

[0037] 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.

[0038] 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, thesyringe 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.

[0039] 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 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.

[0040] 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.

[0041] 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 ofchambers 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.

[0042] 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 the device 6 is withdrawn away from the skin, the activation cap 80 may automatically advance to cover the needle 78.

[0043] 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.

[0044] 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.

[0045] 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 thelike, 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.

[0046] 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 syringe 70 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.

[0047] 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.

[0048] 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 beprovided 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.

[0049] 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 while properly 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.

[0050] 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.

[0051] 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.

[0052] 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, thehousings 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.

[0053] 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 6 may 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.

[0054] 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.

[0055] 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.

[0056] 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 distalcylinder 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.

[0057] 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.

[0058] 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 fluid containing 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.

[0059] 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.

[0060] 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 or other weakened region (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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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 the initial 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.

[0068] 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 plungersthat 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.

[0069] 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 will be appreciated that any of these optional features related to the plunger 50 may be combined together or omitted, as desired.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 directed proximally. 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).

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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 tabs65 causes the locking features 64a to move inwardly, thereby disengaging the locking features 64a from the proximal end 21a of the inner housing 20.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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 may then be cleaned and / or sterilized and a new gas canister 40 may be loaded into the inner housing 20 before reassembling the device.

[0085] As described above, the injector device 6 shown in FIGS. 1-6 or any of the injector devices disclosed in the patents incorporated by reference, includes a drive module 12 that includes a drive housing 20 that includes a gas canister 40, an opener mechanism 60, and a plunger 50. Instead of the drive housing 20, other drive housings may be provided, which may facilitate manufacturing and / or assembly of an injector device and / or which may enhance support of the components of the drive module, e.g., the gas canister and / or components of the opener mechanism.

[0086] For example, turning to FIG. 7, a cross-sectional view of a drive module 112 is shown that includes a drive housing 120 formed from multiple components, e.g., a first or proximal housing 120a and a second or distal housing 120b, which may secure a bulkhead 130 therebetween. An injector including the drive module 112 may include other components, e.g., an injector module including a syringe or other agent chamber, an outer housing, and an actuator (all not shown for clarity), which may automatically or manually activate an opener mechanism to open an outlet of the gas canister within the drive module 112.

[0087] Similar to the previous device 6, the proximal housing 120a includes a first or proximal chamber 122, e.g., that may receive a gas canister and opener mechanism (not shown), and the distal housing 120b includes a second or distal chamber 124, e.g., that may receive a plunger (also not shown). For example, as shown, the proximal housing 120a includes a uniform diameter first region 122a within which the gas canister (not shown) is mounted, and second and third regions 122b, 122c within which components of the opener mechanism, e.g., a carriage and release cap (not shown), are mounted, similar to other devices herein.

[0088] The bulkhead 130 may include a proximal recess 132, e.g., having a concave shape similar to a closed end of a gas canister, such that the gas canister may be seated within the recess 132 to prevent axial movement of the gas canister, e.g., such that the outlet end of the canister is oriented proximally towards the second and third regions 122b, 122c of the first chamber 122. In addition, the bulkhead 130 may include one or more passages 134, e.g., a plurality of grooves or slots, that provide a path for pressurized gas released from the canister to pass from the first chamber 122 into the second chamber 124 around the canister.

[0089] The bulkhead 130 may be mounted within the drive housing 120 between the first and second chambers 122, 124 such that the bulkhead is axially fixed relative to the drive housing 120. For example, as shown, the bulkhead 130 may include an annular shoulder 136 or other radially outward protrusions that may be received within corresponding annular recesses or grooves in the proximal and distal housings 120a, 120b.

[0090] In the example shown, a distal end 123a of the proximal housing 120a and a proximal end 121b of the distal housing 120b may be attached together by a butt joint 127, e.g., substantially permanently by one or more of bonding with adhesive, soldering, welding, sonic welding, fusing, and the like, thereby securing the annular shoulder 136 within a recess between the housings 120a, 120b. In addition or alternatively, the ends 121a, 121b may be attached using one or more mating threads or other connectors, interference fit, and the like, similar to other devices herein.

[0091] A distal end 123b of the distal housing 120b includes an opening through which the plunger (not shown) may be slidably received, e.g., such that the plunger may be coupled to and / or otherwise advance a piston of a syringe of an injector module (not shown), similar to the previous devices. As shown, the distal end 123b may include one or more seals, e.g., O-ring 125, which may slidably engage the plunger to accommodate distal movement of the plunger while providing a fluid-tight seal to prevent pressurized gas within the second chamber 124 from leaking from the drive housing 120.

[0092] The components of the drive module 112, e.g. the proximal and distal housings 120a, 120b and bulkhead 130, may be formed from metal, plastic, or composite material, e.g., by one or more of molding, machining, casting, spinning, and the like, similar to components of the earlier devices.

[0093] During assembly, the gas canister and opener mechanism (e.g., including a carriage, release cap, spring, and the like, not shown) may be inserted into the first chamber122 of the proximal housing 120a, e.g., similar to the device 6. The bulkhead 130 may be positioned against the canister and / or distal end 123a of the proximal housing 120a, e.g., such that closed end of the canister is received within the recess 132, thereby stabilizing and / or axially fixing the canister within the first chamber 122.

[0094] The plunger (not shown) may be inserted into the second chamber 124 and then the ends 123a, 121b of the housings 120a, 120b may be positioned against one another and attached together. Any other components, e.g., release cap, spacer, outer housing, injector module, etc., may be positioned around or adjacent the drive housing 120 to fully assemble an injector device, similar to the device 6 shown in FIGS. 1-6.

[0095] For example, the drive module 112 may be included in an injector that is preassembled during manufacturing, e.g., with a syringe or other injector module positioned adjacent the distal end 223b of the distal housing 220b and / or an outer housing and / or actuator components (not shown) around the drive module 112. Alternatively, the drive module 112 may be assembled with an outer housing and / or actuator components, and then the drive module may be provided to a user separate from an injector module. In this alternative, a user may load a desired syringe, e.g., containing one or more desired agents, into the injector module, couple the loaded injector module to the drive module 112 and perform an injection, similar to the other injector devices herein.

[0096] Turning to FIG. 8, another example of a drive module 212 is shown that includes a drive housing 220 formed from multiple components, e.g., an outer and / or proximal housing w20a and an inner or distal housing 220b, which may secure a bulkhead 130 therebetween. As with the drive module 112, an injector including the drive module 212 may include other components, e.g., an injector module including a syringe or other agent chamber, an outer housing, and an actuator (all not shown for clarity), which may automatically or manually activate the opener mechanism to open an outlet of the gas canister within the first chamber 222.

[0097] In this example, the outer / proximal housing 220 extends substantially the entire length of the drive module 212, including a proximal end 221a and a distal end 223a, and includes a first or proximal chamber 222, which may contain a gas canister and opener mechanism (shown), generally similar to the other drive modules herein. The inner / distal housing 220b includes a proximal end 221b with an integral bulkhead 230, a distal end 223b, and a second or distal chamber 224 that extends distally from the bulkhead 230 to thedistal end 223b. The second chamber 224 receives a plunger (not shown), also generally similar to the other drive modules herein.

[0098] As shown, the inner housing 220b is sized to be slidably received within the outer housing 220a to position the bulkhead 230 at an intermediate location within the outer housing 220a without substantial lateral movement. As with the previous examples, the bulkhead 230 separates the first and second chambers 222, 224, which communicate via one or more grooves or other passages in the bulkhead 230 to allow pressurized gas released by the gas canister (not shown) to pass from the first chamber 222 to the second chamber 224 to advance the plunger.

[0099] Optionally, as shown, the outer housing 220a may include a shoulder or other feature(s) 239 within the outer housing 220a, e.g., at an intermediate location between the proximal and distal ends 221a, 223a, to limit the axial position of the inner housing 222b and bulkhead 230, e.g., such the distal end 223b of the inner housing 220b is positioned adjacent the distal end 223a of the outer housing 220a. [000100] As shown, the drive housing 212 also includes a gland or end member 240, which may be attached to the distal end 223a of the outer housing 220a and / or to the distal end 223b of the inner housing 220b. For example, the gland 240 may include an outer flange that abuts the distal end 223a of the outer housing 220, which may be permanently attached together, e.g., by one or more of welding, soldering, bonding with adhesive, fusing, and / or one or more mating connectors. One or more seals, e.g., O-ring 225 may be provided around an opening in the gland 240, e.g., to allow the plunger to slide therethrough while providing a fluid-tight seal. [000101] The gland 240 may abut the distal end 223b of the inner housing 220b when attached to the outer housing 220a to prevent axial movement of the inner housing 220b and bulkhead 240. Thus, in this example, the bulkhead 240 and inner housing 220b may be integrally formed as a single component that are axially fixed between the shoulder 239 and the gland 240. For example, the inner housing 220b and bulkhead 230 may be integrally formed from one piece, e.g., by one or more of molding, casting, machining, and the like, or the tubular portion of the inner housing and the bulkhead may be formed separately and then attached together before inserting into the outer housing 220a. Otherwise, the components of the drive housing 212 may be constructed and / or assembled similar to the other drive modules herein. The drive housing 212 may be included in an injector device,e.g., to replace the drive housing of the device 6 of FIGS. 1-6, similar to the drive module 112. [000102] Optionally, as shown in FIG. 9, one or more sleeves 250 may be provided around a drive housing 312. In the example shown, the drive housing 312 includes a proximal or outer housing 320a that receives a distal or inner housing 320b including an integral bulkhead 330, e.g., generally similar to the drive module 212 (or any of the other drive modules described herein). In this example, however, one or more sleeves 328 may be provided around the outer housing 320a, which may be formed from metal, plastic, or composite materials with enhance strength to reinforce the drive module 312. The sleeve(s) 328 may be secured to the outer housing 320 by one or more of interference fit, bonding with adhesive, fusing, welding, over-molding, applying and curing, and the like. In addition or alternatively, other external reinforcement may be provided, e.g. by winding one or more of filament, roving, tape, and the like (not shown) around the outer housing 320a, e.g., substantially along the entire length between the proximal and distal ends 321a, 323a or simply around the first and / or second chambers 322, 324. [000103] Turning to FIG. 10, still another example of a drive housing 412 is shown, which includes a two-piece outer housing, e.g., including a first or proximal housing 420a and a second or distal housing 420b, which are attached together. For example, a distal end 423a of the proximal housing 420a may be lapped or otherwise received at least partially over a proximal end 421b of the distal housing 420b (or vice versa). As shown, the ends 423a, 421b include angled surfaces providing a frusto-conical lap joint, which may be permanently attached together by one or more of interference fit, bonding with adhesive, fusing, welding, and the like. Alternatively, the joint may be cylindrical or planar, e.g., with the ends 423a, 421b having uniform diameters with one slightly smaller than the other, or the ends 423a, 421b may be attached using a butt joint (not shown). [000104] In addition, the drive housing 412 includes a bulkhead 430 that is received within the drive housing 420, e.g., such that the bulkhead 430 is axially fixed at an intermediate location. In this example, the bulkhead 430 includes a tubular extension 438 that extends distally from the bulkhead 430 to a distal end 438b located adjacent the distal end 423b of the distal housing 420b. The tubular extension 438 provides the distal or second chamber 424 that receives the plunger (not shown), e.g., similar to the drive module 312.[000105] Similar to the other devices herein, one or more seals, e.g., O-ring 425 may be provided around a distal opening to slidably engage the plunger while providing a fluid- tight seal. In the example shown, the distal end 423b of the distal housing 420b tapers inwardly to provide a gland and distal opening of the drive module 412 (through which the plunger advances). Alternatively, the distal end 438b of the tubular extension 438 may provide the distal opening and / or include one or more seals. [000106] To assemble the drive module 412, a gas canister and opener mechanism may be inserted into the first chamber 422, e.g., into the distal end 423a of the proximal housing 420 and the bulkhead 430 and tubular extension 438 (along with the plunger, not shown) may be inserted into the distal housing 420b, e.g., from the proximal end 421b. In the example shown, the bulkhead 430 includes an annular shoulder or other radially outward projections 436, which may be received in one or more corresponding annular recesses or grooves in the ends 423a, 421b of the proximal and distal housings 420a, 420b, when the ends 432a, 421b are directed together to provide the joint 423. Thus, the bulkhead 430 and tubular extension 438 are thereafter axially fixed relative to the housings 420a, 420b, which may be attached together as described previously. [000107] Turning to FIG. 11, another example of a drive module 512 is shown that includes a two-piece outer housing, e.g., including a first or proximal housing 520a and a second or distal housing 520b, which are attached together, e.g., using a butt joint 529. A bulkhead 530 may be provided separate from the housings 520a, 520b, which may be secured between the ends 523a, 521b defining the butt joint 529. For example, the bulkhead 530 includes an annular shoulder or other radial protrusions 536 that are received within annular recesses within the ends 523a, 521b such that the bulkhead 530 is axially fixed within the housings 520a, 520b, similar to other drive modules herein. [000108] During assembly, a gas canister and opener mechanism (not shown) may be received in the first chamber 522, and the bulkhead may be positioned over the closed end of the canister and / or against the distal end 523a. A plunger may be inserted into the second chamber 524 and the proximal end 521b of the distal housing 520b may be positioned against the distal end 523a of the proximal housing 520a, and then the butt joint may be formed to attach the housings 520a, 520b together. Alternatively, the bulkhead 530 may be positioned in the proximal end 521b of the distal housing 520b (e.g., after inserting the plunger), and the bulkhead 530 may be directed into contact with the canister when the ends 521b, 523a are brought together, thereby capturing the shoulder 536 therebetween.[000109] Similar to other devices herein, the components of the drive module 512 may be formed from metal, plastic, or composite materials, e.g., by one or more of molding, casting, machining, laser cutting, and the like. The butt joint may be formed by one or more welding, soldering, bonding with adhesive, fusing, and the like. For example, a weld may be formed by laser, electron-beam, electric arc welding, and the like, with or without filler material. A bonded joint may be formed with adhesive, solvent, and the like. [000110] Optionally, the bulkhead 530 may include a tubular extension (not shown), e.g., extending distally to the distal end 523b within the distal housing 520b. As shown, the distal end 523b of the distal housing 520b may include a tapered or otherwise shaped end, including an opening through which the plunger may slide. One or more seals, e.g., O-ring 525 may be provided around the opening to slidably engage the plunger while providing a fluid-tight seal. Alternatively, a separate gland or end member (not shown) may be provided that may be attached to the distal end 523b of the distal housing 520b, similar to other devices herein. [000111] Alternatively, as shown in FIG. 12, a drive module 612 may be provided that includes proximal and distal housings 620a, 620b, which are threaded together. For example, as shown, the proximal end 621b of the distal housing 620b may include outer threads, and the distal end 623a of the proximal housing 620a may include inner threads that may be threaded over the outer threads to attach the housings 620a, 620b together (alone or in combination with welding, bonding with adhesive, etc., if desired). Alternatively, the threads may be reversed, if desired. Optionally, in this example, one or more seals may be provided between the ends 621b, 623a, e.g., an O-ring 625b, which may be provided around the bulkhead 630 and / or otherwise between the ends to provide a fluid-tight connection. [000112] In a further alternative, shown in FIG. 13, proximal and distal housings 720a, 720b of a drive module 712 may be attached together by an overlap joint 729. As shown, a proximal end 721b of the distal housing 720b may be slidably received over a distal end 723a of the proximal housing 720a. Optionally, the bulkhead 730 may include an annular shoulder 736 or other outward projections that may be received within recesses in the ends 721b, 723a to axially fix the bulkhead 730 within the housings 720a, 720b, similar to other devices herein. The overlap joint 729 may permanently attach the housings 720a, 720b together, e.g., by one or more of an interference fit, welding, soldering, bonding with adhesive, fusing, and the like.[000113] Turning to FIG. 14, another example of a drive module 812 is shown that includes a drive housing 820 formed from a single tubular structure, e.g., including regions corresponding to the first or proximal chamber 822 and the second or distal chamber 824. As with other drive modules herein, the drive module 812 may include other components, e.g., a gas canister and opener mechanism (not shown) received in the first chamber 822, a plunger (also not shown) received in the second chamber 824, and one or more external or internal actuator components. An injector device including the injector module 812 may include a syringe or other agent chamber, an outer housing, and an actuator (all not shown for clarity), which may automatically or manually activate the opener mechanism to open an outlet of the gas canister within the first chamber 822. [000114] The drive housing 820 extends substantially the entire length of the drive module 812, including a proximal end 821 and a distal end 823. A bulkhead 830 is mounted within the drive housing 820, e.g., at an intermediate location separating the first and second chambers 822, 824, but including one or more passages allowing pressurized gas released from the canister to pass from the first chamber 822 into the second chamber 824, similar to other devices herein. [000115] In this example, the drive housing 820 includes one or more features for axially fixing the bulkhead 830. For example, the drive housing 820 may include a shoulder or other feature(s) 839 within the drive housing 820 that limits proximal movement (to the right in FIG. 14) of the bulkhead 830. For example, during assembly, the bulkhead 830 may be inserted into the second chamber 824 from the distal end 823 of the drive housing 820 (e.g., after inserting the gas canister and opened mechanism) and directed proximally until the bulkhead 830 abuts the shoulder 839. To prevent subsequent distal movement of the bulkhead 830, a swage 832 may be formed in the drive housing 820 immediately distal to the bulkhead 830. For example, the drive housing 820 may be formed from metal or other material that may be malleable or otherwise deformable such that, after positioning the bulkhead 830 against the shoulder 839, a tool may be used to deform the wall of the drive housing 820 inwardly to form the swage 832, e.g., to press the wall against a distal end of the bulkhead 830. Alternatively, the material of the drive housing 820 may be heated or otherwise softened, e.g., in the case of plastic material, and then pressed inwardly against the bulkhead 830. Once the material cools, the resulting swage 832 prevents subsequent movement of the bulkhead 830.[000116] In addition, as shown, the drive housing 812 also includes a gland or end member 840, which may be attached to the distal end 823 of the drive housing 820, e.g., to provide a desired opening at the distal end 823 through which the plunger may slide. One or more seals, e.g., O-ring 825 may be provided around an opening in the gland 840, e.g., to allow the plunger to slide therethrough while providing a fluid-tight seal. The gland 840 may be attached to the drive housing 820, e.g., by one or more of mating connectors, interference fit, welding, soldering, fusing, bonding with adhesive, and the like. [000117] In one example, the gland 840 may be a tubular member sized to be slidably received within the distal end 823 and secured therein, e.g., by one or more fingers, detents, or other features 823a on the distal end 823 that may be received in corresponding pockets or recesses in the gland 840. The fingers 823a may be biased inwardly such that they slide over the gland 840 until they are positioned over the pockets, whereupon they may resiliently snap in to secure the gland 840. In addition or alternatively, an outer sleeve 842 may be provided, which may be positioned around the proximal end 832 of the drive housing 820 to secure the fingers 823a within the pockets. The sleeve 842 may be permanently attached around the drive housing 820, e.g., by one or more of welding, soldering, fusing, bonding with adhesive, shrink fit, and the like. In addition or alternatively, another swage (not shown) may be formed in the drive housing 820 around the gland 840 to engage the wall of the drive housing 820 against the gland 840. [000118] Similar to the other devices herein, the gland 840 may include one or more seals, e.g., an O-ring 825a that slidably engages the plunger while providing a fluid-tight seal. Optionally, one or more additional O-rings or seals 825b may be provided between the gland 840 and the drive housing 820 to substantially seal the distal end 823 to prevent pressurized gas from escaping from the second chamber 824. [000119] Turning to FIG. 15, another example of a drive module 912 is shown that includes a drive housing 920, a bulkhead 930, and a gland or end member 940, which may generally be constructed similar to other devices herein. As with other drive modules herein, the drive module 912 may include other components, e.g., a gas canister and opener mechanism (not shown) received in a first chamber 922, a plunger (also not shown) received in the second chamber 924, and one or more external or internal actuator components. [000120] Similar to the drive module 812, the drive housing 920 is formed from a single tubular structure, e.g., including regions corresponding to the first or proximalchamber 922 and the second or distal chamber 924, e.g., such that the drive housing 920 extends substantially the entire length of the drive module 912, including a proximal end 921 and a distal end 923. The bulkhead 930 is mounted within the drive housing 920, e.g., at an intermediate location separating the first and second chambers 922, 924, but including one or more passages allowing pressurized gas released from the canister to pass from the first chamber 922 into the second chamber 924, similar to other devices herein. [000121] For example, the drive housing 920 may include a shoulder or other feature(s) 939 within the drive housing 920 that limits proximal movement (to the right in FIG. 14) of the bulkhead 930. During assembly, the bulkhead 930 may be inserted into the second chamber 924 from the distal end 923 of the drive housing 920 (e.g., after inserting the gas canister and opened mechanism) and directed proximally until the bulkhead 930 abuts the shoulder 939. [000122] To prevent the bulkhead 930 from moving distally after assembly, the gland or end member 940 includes proximal and distal glands 940a, 940b. The proximal gland 940a is sized to be inserted into the distal end 923 and the second chamber 924 during assembly. The proximal gland member 940a may be a tubular member having sufficient length such that a proximal end 941a thereof abuts the bulkhead 930 when fully inserted and a distal end 943a thereof is located adjacent the distal end 923 of the drive housing 920, as shown. For example, the bulkhead 930 may include an annular groove or other feature that receives the proximal end 941a to prevent axial movement of the bulkhead 930. [000123] The distal gland 940b is sized to be received within the distal end 923 of the drive housing 920, e.g., between the drive housing 920 and the distal end 943a of the proximal gland 940a. The distal gland 940b may be secured or otherwise attached to the distal end 923 of the drive housing 920, thereby preventing subsequent axial movement of the proximal gland 940a and the bulkhead 930. For example, similar to the device module 812, the distal end 923 of the drive housing 920 may include a plurality of fingers, detents, or other features 923a that may be received in pockets of the distal gland 940b and a sleeve 942 may be secured around the distal end 923 once the fingers 923a are received in the pockets. In addition or alternatively, the distal gland 940b may be permanently attached to the distal end 923 of the drive housing 920, e.g., using one or more of welding, soldering, fusing, bonding with adhesive, and the like. [000124] Optionally, one or more O-rings or other seals 925b may be provided around and / or between the proximal and distal glands 940a, 940b and / or the distal end 923 of thedrive housing 920 to provide a fluid-tight seal at any connection locations. In addition, an O-ring or other seal 925a may be provided around an opening through the distal gland 940b, e.g., to slidably engage the plunger while preventing pressurized gas from escaping from the second chamber 924, similar to other devices herein. [000125] Turning to FIG. 16, still another variation of a drive module 1012 is shown, which includes a single piece drive housing 1020, a bulkhead 1030, which may be secured within the drive housing 1020 between a shoulder 1039 and a swage 1032, e.g., similar to drive module 812. In this example, a gland or end member 1040 is provided that may be secured or otherwise attached to a distal end 1023 of the drive housing 1020, e.g., after inserting the bulkhead 1030 and other components (e.g., a gas canister and opener mechanism). As shown, the gland 1040 and the distal end 1023 of the drive housing 1020 may including mating threads such that the gland 1040 may be threaded into the drive housing 1020, e.g., until the gland 1040 abuts the distal end 1023. Optionally, one or more seals, e.g., O-ring 1025b, positioned around the gland 1040 or otherwise between the gland 1040 and the drive housing 1020 to provide a fluid-tight seal at the threaded connection. In addition or alternatively, the gland 1040 may be attached to the distal end 1023 by one or more of welding, soldering, fusing, bonding with adhesive, and the like. Similar to other devices herein, the gland 1040 may include one or more seals, e.g., O-ring 1025a around the opening through which the plunger extends. [000126] Turning to FIGS. 17A and 17B, another variation of a drive module 1112 is shown, which includes an outer drive housing 1120a, an inner drive housing 1120b including a bulkhead 1130, and a gland or end member 1140. The outer drive housing 1120a may be constructed to other drive modules herein, e.g., including proximal and distal ends 1121a, 1123a. [000127] As shown, the outer housing 1120a extends substantially the entire length of the drive module 1112, including a proximal end 1121a and a distal end 1123a, and includes a first or proximal chamber 1122, which may contain a gas canister and opener mechanism (shown), generally similar to the other drive modules herein. The inner housing 1120b includes a proximal end 1121b with an integral bulkhead 1130, a distal end 1123b, and a second or distal chamber 1124 that extends distally from the bulkhead 1130 to the distal end 1123b, which receives a plunger (not shown), also generally similar to the other drive modules herein.[000128] As shown, the inner housing 1120b is sized to be slidably received within the outer housing 1120a to position the bulkhead 1130 at an intermediate location within the outer housing 1120a. As with the previous examples, the bulkhead 1130 separates the first and second chambers 1122, 1124, which communicate via one or more grooves or other passages in the bulkhead 1130 to allow pressurized gas released by the gas canister (not shown) to pass from the first chamber 1122 to the second chamber 1124 to advance the plunger. [000129] Optionally, as shown, the outer housing 1120a may include a shoulder or other feature(s) 1139, e.g., at an intermediate location between the proximal and distal ends 1121a, 1123a, to limit the axial position of the inner housing 1122b and bulkhead 1130, e.g., such the distal end 1123b of the inner housing 1120b is positioned adjacent the distal end 1123a of the outer housing 1120a. [000130] The gland or end member 1140 may be attached to the distal end 1123a of the outer housing 1120a and / or to the distal end 1123b of the inner housing 1120b. For example, as shown, the gland 1140 may be inserted into the distal end 1123a of the outer housing 1120a, and the distal end 1123a may be swaged or otherwise deformed inwardly around the gland 1140 to permanently attached the gland 110 within the distal end 1123a, thereby axially fixing the gland 1140, the inner housing 1120b, and the bulkhead 1130 within the outer housing 1120a. In addition or alternatively, the gland 1140 may be further attached to the outer housing 1120a, e.g., by one or more of welding, soldering, bonding with adhesive, fusing, and / or one or more mating connectors. Optionally one or more seals, e.g., O-ring 1125b may be provided between the gland 1140 and the drive housing 1120a to provide a fluid-tight seal, and an O-ring 1125a may be provided around an opening in the gland 1140, e.g., to allow the plunger to slide therethrough while providing a fluid-tight seal, similar to the other devices herein. [000131] 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 the particular 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 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 adjacent the first end including an opener pin; a canister containing pressurized gas including an outlet disposed adjacent the opener pin; an actuator configured to move one of the opener mechanism and the canister to cause the opener 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 slidably comprising a proximal end disposed within the second chamber such that pressurized gas entering the second chamber causes the plunger to move from an initial position to an extended position where a distal end of the plunger extends from the second end of the drive housing, 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; wherein the drive housing comprises a bulkhead dividing the first and second chambers and configured to at least partially receive the canister.

2. The drive module of claim 1, wherein the drive housing comprises a proximal portion, a distal portion, and a bulkhead portion attached between the proximal and distal portions.

3. The drive module of claim 2, wherein the bulkhead portion is at least partially received within a recess between a proximal end of the distal portion and a distal end of the proximal portion.

4. The drive module of claim 1, wherein the drive housing comprises an outer housing defining the first and second ends and an inner housing carrying the bulkheadreceived within the outer housing to position the bulkhead at an intermediate location between the first and second ends.

5. The drive module of claim 4, wherein the inner housing comprises a tubular body extending from the bulkhead towards the second end of the outer housing, the drive module further comprising a gland or end member connected to the second end of the outer housing to secure the inner housing.

6. The drive module of claim 5, wherein the gland or end member comprises a seal providing a seal around the plunger while allowing the distal end of the plunger to slide distally from the second end of the outer housing.

7. The drive module of claim 4, wherein the outer housing comprises first and second outer portions and wherein the bulkhead is attached between the first and second outer portions.

8. The drive module of claim 7, wherein the bulkhead is at least partially received within a recess defined by the first and second outer portions.

9. The drive module of claim 8, wherein the second outer portion comprises a seal providing a seal around the plunger while allowing the distal end of the plunger to slide distally from the second end of the outer housing.

10. The drive module of claim 1, wherein the drive housing comprises: an outer housing comprising the first and second ends; a bulkhead portion attached at an intermediate location between the first and second ends; and a gland or end member attached to the second end of the outer housing.

11. The drive module of claim 10, wherein the bulkhead portion is attached at the intermediate location by swaging the outer housing.

12. The drive module of claim 10, wherein the gland or end member is attached to the second end of the outer housing by one or more of cooperating fingers, a sleeve, and cooperating threads.

13. The drive module of claim 10, wherein the gland or end member comprises a tubular body extending into the outer housing from the second end to abut the bulkhead portion to prevent movement of the bulkhead portion.

14. The drive module of claim 13, wherein the end member comprises a first portion comprising the tubular body and a second portion attached to the second end of the outer housing to secure the first portion and the bulkhead portion.

15. The drive module of claim 13, wherein the gland or end member is attached to the second end of the outer housing by swaging the outer housing.

16. The drive module of any one of claims 1-15, wherein the components of the drive housing are permanently attached together by one or more of interference fit, lap joints, cooperating threads, bonding with adhesive, welding, and fusing.

17. The drive module of any one of claims 1-15, wherein the bulkhead comprises a concave recess therein for receiving the canister.

18. The drive module of any one of claims 1-15, wherein the opener mechanism comprises a carriage carrying the opener pin and a release cap coupled to the carriage, and wherein 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; 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 drive 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 consequentlydirecting the release cap proximally to release the carriage, whereupon the opener pin opens the outlet to release the pressurized gas into the first chamber and into the second chamber such that the pressurized gas advances the plunger to direct the piston distally to deliver the one or more agents.

19. The drive module of claim 18, 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.

20. The drive module of any one of claims 1-15, 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 opener pin to open the outlet and release the pressurized gas.

21. The drive module of any one of claims 1-15, 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 pressurized gas.

22. The drive module of claim 21, wherein the manual actuator comprises one of a screw, a button, and a lever.

23. 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 adjacent the first end including an opener pin;a canister containing pressurized gas including an outlet disposed adjacent the opener pin; an actuator configured to move one of the opener mechanism and the canister to cause the opener 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 pressurized gas entering the second chamber causes the plunger to move from an initial position to an extended position, a distal end of the plunger coupled to the piston of the injector module to advance the piston to deliver the one or more agents from the agent chamber; wherein the drive housing comprises a bulkhead dividing the first and second chambers and configured to at least partially receive the canister.

24. The device of claim 23, wherein the drive housing comprises a proximal portion, a distal portion, and a bulkhead portion attached between the proximal and distal portions.

25. The device of claim 24, wherein the bulkhead portion is at least partially received within a recess between a proximal end of the distal portion and a distal end of the proximal portion.

26. The device of claim 23, wherein the drive housing comprises an outer housing defining the first and second ends and an inner housing carrying the bulkhead received within the outer housing to position the bulkhead at an intermediate location between the first and second ends.

27. The device of claim 26, wherein the inner housing comprises a tubular body extending from the bulkhead towards the second end of the outer housing, the drive module further comprising a gland or end member connected to the second end of the outer housing to secure the inner housing.

28. The device of claim 27, wherein the gland or end member comprises a seal providing a seal around the plunger while allowing the plunger to slide distally from the second end of the outer housing.

29. The device of claim 26, wherein the outer housing comprises first and second outer portions and wherein the bulkhead is attached between the first and second outer portions.

30. The device of claim 29, wherein the bulkhead is at least partially received within a recess defined by the first and second outer portions.

31. The device of claim 30, wherein the second outer portion comprises a seal providing a seal around the plunger while allowing the plunger to slide distally from the second end of the outer housing.

32. The device of claim 23, wherein the drive housing comprises: an outer housing comprising the first and second ends; a bulkhead portion attached at an intermediate location between the first and second ends; and a gland or end member attached to the second end of the outer housing.

33. The device of claim 32, wherein the bulkhead portion is attached at the intermediate location by swaging the outer housing.

34. The device of claim 32, wherein the gland or end member is attached to the second end of the outer housing by one or more of cooperating fingers, a sleeve, and cooperating threads.

35. The device of claim 32, wherein the gland or end member comprises a tubular body extending into the outer housing from the second end to abut the bulkhead portion to prevent movement of the bulkhead portion.

36. The device of claim 35, wherein the gland or end member comprises a first portion comprising the tubular body and a second portion attached to the second end of the outer housing to secure the first portion and the bulkhead portion.

37. The device of claim 35, wherein the gland or end member is attached to the second end of the outer housing by swaging the outer housing.

38. The device of any one of claims 23-37, wherein the components of the drive housing are permanently attached together by one or more of interference fit, lap joints, cooperating threads, bonding with adhesive, welding, and fusing.

39. The device of any one of claims 23-37, wherein the bulkhead comprises a concave recess therein for receiving the canister.

40. The device of any one of claims 23-37, wherein the opener mechanism comprises a carriage carrying the opener pin and a release cap coupled to the carriage, and wherein 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; 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 drive 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 carriage, whereupon the opener pin opens the outlet to release the pressurized gas into the first chamber and into the second chamber such that the pressurized gas advances the plunger to direct the piston distally to deliver the one or more agents.

41. The device of one of claims 23-37, 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 theactivation 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.

42. The device of any one of claims 23-37, 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 opener pin to open the outlet and release the pressurized gas.

43. The device of any one of claims 23-37, 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 pressurized gas.

44. The device of claim 43, wherein the manual actuator comprises one of a screw, a button, and a lever.

45. The device of one of claims 23-37, further comprising an outer device housing carrying the drive housing and wherein the injector module comprises a syringe received within the outer device housing adjacent the drive housing.

46. A method for assembling a drive module for an injector device including an injector module comprising an agent chamber containing one or more agents and a piston, the method comprising: providing 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; positioning an opener mechanism and a canister containing pressurized gas within the first chamber such that an outlet of the canister is disposed adjacent an opener pin of the opener mechanism; mounting a bulkhead within the drive housing separating the first and second chambers, the bulkhead comprising one or more passages communicating between the first and second chambers; coupling an actuator to the opener mechanism such that activation of the actuator causes the opener pin to open the outlet and cause the gas within the canister to flow from the first chamber into the second chamber via the one or more passages; andproviding a plunger comprising a proximal end disposed within the second chamber such that pressurized gas entering the second chamber causes the plunger to move from an initial position to an extended position where a distal end of the plunger extends from the second end of the drive housing, 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.

47. The method of claim 46, wherein providing the drive housing comprises: providing a proximal housing comprising the first chamber and a distal housing comprising the second chamber; and attaching ends of the proximal and distal housings together to provide the drive housing.

48. The method of claim 47, wherein the bulkhead is mounted between the ends of the proximal and distal housings when the ends are attached together.

49. The method of claim 47, wherein the ends of the proximal and distal housings comprise one or more recesses and wherein the bulkhead comprises one or more protrusions that are received within the one or more recesses to mount the bulkhead within the drive housing.

50. The method of claim 46, wherein mounting the bulkhead comprises: inserting the bulkhead into the second end of the drive housing until the bulkhead is received at an intermediate location separating the first and second chambers; and attaching the bulkhead at the intermediate location.

51. The method of claim 50, wherein the bulkhead is attached at the intermediate location by swaging a wall of the drive housing adjacent the bulkhead.

52. The method of claim 50, wherein the bulkhead is inserted into the second end until the bulkhead contacts a shoulder within the drive housing that prevents further insertion of the bulkhead.

53. The method of claim 52, wherein attaching the bulkhead comprises swaging a wall of the drive housing to form a swage such that the bulkhead is axially fixed between the swage and the shoulder.

54. The method of claim 52, wherein the bulkhead comprises a tubular extension extending from the bulkhead to an extension end and wherein the bulkhead is inserted into the second end until the extension end is positioned adjacent the second end.

55. The method of claim 54, further comprising attaching a gland or end member to the second end to prevent axial movement of the tubular extension.

56. The method of claim 50, wherein attaching the bulkhead comprises inserting a tubular member into the second end such that the tubular member contacts the bulkhead to prevent axial movement of the bulkhead.

57. The method of claim 56, further comprising attaching a gland or end member to the second end to prevent axial movement of the tubular member and the bulkhead.

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