Infusion systems and methods

Abstract

To provide a multi-chamber safety injection system with precise control of handling, mixing and delivery of multi-component injectables.SOLUTION: The system also includes proximal and distal stoppers disposed in a syringe body, forming respective proximal and distal drug chambers. The system further includes a plunger member configured to be manually manipulated to insert the proximal stopper member relative to the syringe body. Moreover, the system includes a fluid conveying assembly 830, where the fluid conveying assembly includes: a penetrating member 840 configured to penetrate the distal stopper member to fluidly couple the proximal and distal drug chambers, a distal exit tube 850, and a transfer member 860 disposed at least partially around a portion of the penetrating member and defining a fluid passage. A distal end of the penetrating member is disposed in the distal exit tube.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present disclosure relates generally to injection systems, devices and processes for facilitating various levels of control over fluid injection, and more particularly to systems and methods relating to multi-chamber safety syringes in medical environments. [Background technology]

[0002] Millions of syringes, such as the one shown in FIG. 1A (2), are consumed daily in healthcare settings. A typical syringe (2) includes a tubular body (4), a plunger (6), and a needle (8). As shown in FIG. 1B, such syringes (2) can be utilized not only to inject fluids into patients but also to withdraw or expel fluids from or into containers such as vials, bags, or other drug containment systems (10). In fact, in some countries, such as the United States, due to concerns about maintaining sterility and regulatory constraints, if syringes (2) are used with vials (10) in certain patient settings, as shown, such vials must be used only with a single patient and then disposed of, resulting in significant medical waste from vials and remaining medication and contributing to periodic shortages of certain critical medications. Referring to FIG. 2A, three luer-type syringes (12) are shown, each having a distally disposed luer fitting configuration (14) for mating with other devices having a similar fitting configuration, such as the luer manifold assembly (16) shown in FIG. 2B. The luer manifold assembly of FIG. 2B can be used to administer liquid medications intravenously to a patient, with or without the use of an intravenous infusion bag. The luer fittings (14) of the syringes in FIG. 2A are sometimes referred to as "male" luer fittings, and the luer fittings (18) of FIG. 2B are sometimes referred to as "female" luer fittings, with one of the luer interfaces being threaded (in which case the configuration is sometimes referred to as a "luer lock" configuration) to couple the two through relative rotation, which may be combined with a compressive load. In other words, in one embodiment of a luer lock, rotation, possibly along with compression, is utilized to engage the threads of the male fitting (14), which are configured to engage a flange on the female fitting (18) to bring the device into a fluid-tight union. In another embodiment, a tapered interface shape may be utilized to provide the luer engagement using compression, without threads or rotation (such a configuration may be referred to as a "slip-on" or "conical" luer configuration).While such luer connections are perceived as relatively safe for the operator, there is a risk of spillage, leakage, or component damage during assembly of the luer connection. On the other hand, the use of needle injection configurations poses a risk of the sharp needle contacting or puncturing a person or unwanted structures. For these reasons, so-called "safety syringes" have been developed.

[0003] One embodiment of a safety syringe 20 is shown in FIG. 3, in which a tubular shield member 22 is spring-biased to cover the needle 8 when released from a locked position relative to the syringe body 4. Another embodiment of a safety syringe 24 is shown in FIGS. 4A and 4B. In this configuration, a retractable needle 26 is configured to retract (28, 26) into a safe position within the tubular body 4 after the plunger 6 is fully inserted into the syringe body 4, as shown in FIG. 4B. Such self-retracting configurations may be associated with issues of blood splatter / aerosolization, safe storage of pre-loaded energy that could result in premature activation, loss of precision in delivering a full dose injection due to residual dead space within the spring compression volume, and / or loss of retraction speed control, which may be associated with pain or patient discomfort.

[0004] The syringe market has become more complex due to the increasing demand for pre-filled syringe assemblies such as those shown in Figures 5A and 5B, which generally comprise a syringe body or "drug containment and delivery system" (34), a plunger tip, plug or stopper (36), and a distal seal or cap (35) attached to a luer interface (Figure 5A shows the cap 35 in place, while Figure 5B has the cap removed to illustrate the luer interface 14). The liquid drug resides in a volume or drug reservoir (40) between the distal seal and the distal end (37) of the plunger tip (36). The plunger tip (36) can comprise a standard butyl rubber material and is coated with a biocompatible lubricious coating (e.g., polytetrafluoroethylene ("PTFE") or the like) to facilitate favorable sealing and relative motion characteristics relative to the associated syringe body structure and material. The proximal end of the syringe body (34) in FIG. 5B comprises a conventional one-piece syringe flange (38) formed integrally with the material of the syringe body (34). The flange (38) is configured to extend radially from the syringe body (34) and to circumferentially surround or partially surround the syringe body (34). A partial flange is known as a "clipped flange," and the other flange The flange is known as a "full flange." The flange is used to grip the syringe with the fingers and provides support for depressing the plunger to perform the injection. The syringe body (34) preferably comprises a translucent material, such as glass or a polymer. A plunger tip (36) can be disposed within the syringe body (34) to form a contained volume within the chamber or reservoir (40) and aid in the evacuation of the associated fluid through the needle. The syringe body (34) can define a generally cylindrical shape (i.e., such that a plunger tip 36 having a circular cross-sectional shape establishes a seal with the syringe body (34)) or can be configured to have other cross-sectional shapes, such as an oval.

[0005] Such assemblies are desirable because they can be standardized and precisely mass-produced by the few manufacturers in the world who can afford to meet all of the world's ever-changing regulations regarding filling, packaging, and drug / drug interfacing material selection and component use. However, such simple configurations generally cannot meet new global standards for single-use, safety, self-disabling, and needlestick protection. For this reason, certain suppliers have turned to more "vertical" solutions, such as those shown in Figure 5C, which attempt to meet all or at least part of the standards in a single solution. However, as a result of attempting to meet those standards in many different scenarios, such products have significant limitations (including those discussed above with reference to Figures 3-4B) and can have relatively high inventory and usage costs.

[0006] In some cases, multi-component infusion systems can mix injectable components (e.g., liquids and / or powders) prior to injection. Some systems utilize a single injection device to draw component liquids from one container and transfer the liquid components to another container, solubilizing the dry components therein. The solubilized dry components are then drawn into the injection device for injection into the patient. Such systems require extensive handling of exposed needles, unnecessarily exposing users to one or more uncapped needles. Furthermore, manually transferring liquid components from one container to another can result in incomplete transfer of the liquid components, affecting the component ratios in the final mixed infusate. Furthermore, accessing and manipulating multiple component containers complicates the injection process, thereby increasing the risk of user error. Therefore, a multi-component infusion system is needed that simplifies manual access to and mixing of multiple components from multiple containers.

[0007] These limitations are addressed by multi-chamber injection systems configured to mix and inject multiple components. However, there remains a need for precise control of multi-chamber injection systems to accurately handle, mix, and deliver multi-component injectates.

[0008] Furthermore, the increase in the amount of liquids (eg, pharmaceuticals) that may be injected creates an additional requirement to minimize the time that such liquids are exposed to metal (eg, the stainless steel of the needle).

[0009] It is also desirable to incorporate anti-needlestick technology into injection systems. The ability to at least partially retract the sharp end of the needle within the syringe protects the injection personnel and the patient from inadvertent needlestick injuries.

[0010] There is a need for an injection system that addresses the shortcomings of currently available configurations, particularly a precisely controlled, multi-chamber safety injection solution that can take advantage of the existing, relatively well-controlled supply chain of conventionally provided pre-filled syringe assemblies, such as those described with reference to Figures 5A and 5B. Summary of the Invention

[0011] FIELD OF THE INVENTION

[0002] Embodiments relate to infusion systems. In particular, embodiments are directed to a multi-chamber safety infusion system that precisely controls the handling, mixing, and delivery of multi-component infusions.

[0012] In one embodiment, an injection system includes a syringe body defining a proximal opening at a proximal end and a distal needle interface at a distal end. The system also includes proximal and distal stop members disposed within the syringe body, forming a proximal drug chamber between the proximal and distal stop members and a distal drug chamber between the distal stop member and the distal end of the syringe body. The system further includes a plunger member configured to be manually operated to insert the proximal stop member relative to the syringe body. The system further includes a fluid transfer assembly including a piercing member configured to pierce the distal stop member to fluidly couple the proximal and distal drug chambers. The fluid transfer assembly also includes a distal outlet tube, the distal end of the piercing member being disposed within the distal outlet tube. The fluid transfer assembly further includes a transfer member disposed at least partially around a portion of the piercing member, the distal transfer member defining a fluid passageway.

[0013] In one or more embodiments, the transfer member includes a sleeve disposed over a portion of the penetrating member. The sleeve can define a fluid passageway on a surface of the portion of the penetrating member. The transfer member can include a chamfered corner at its proximal end. The diameter of the distal end of the geometric feature can be substantially the same as or greater than the diameter of the proximal end of the distal outlet tube. The penetrating member can be configured to penetrate the distal stop member, and the transfer member can be configured to expand the distal stop member and maintain an open fluid passageway.

[0014] In one or more embodiments, a portion of the penetrating member has a reduced diameter relative to the geometric feature at the distal end of the penetrating member and the distal exit tube at the proximal end of the penetrating member portion, and the distal end of the geometric feature and the proximal end of the distal exit tube can form proximal and distal shoulders at the proximal and distal ends of the penetrating member portion, respectively.

[0015] In one or more embodiments, the transfer member has a closed configuration and an open configuration, where in the closed configuration, the transfer member is disposed around a portion of the penetrating member between a proximal shoulder and a distal shoulder, the transfer member having a first diameter, and in the open configuration, the transfer member has a second diameter greater than the first diameter such that the penetrating member and the distal exit tube are slidable within the transfer member. The transfer member can be converted from the closed configuration to the open configuration by applying about 6 lbf to about 10 lbf (pound-force) to the distal exit tube, provided by fluid pressure from the plunger member to the distal stop member.

[0016] In one or more embodiments, the transfer member includes a distally facing funnel at its distal end. The proximal end of the distal outlet tube is disposed within the distally facing funnel when the transfer member is in the closed configuration. The proximal end of the distal outlet tube may be configured to wedge open the transfer member upon distal movement of the distal outlet tube relative to the transfer member, thereby converting the transfer member from the closed configuration to the open configuration.

[0017] In one or more embodiments, the first diameter is equal to or less than the diameter of the distal end of the geometric feature. The second diameter may be greater than the diameter of the proximal end of the distal outlet tube. The transfer member may be configured to transition from the closed configuration to the open configuration by applying a predetermined amount of force to the distal outlet tube. The predetermined amount of force may be a distally directed force of about 6 lbf to about 10 lbf.

[0018] In one or more embodiments, the transfer member includes a living hinge. The transfer member can include an elongated side opening. The distal stop member can include a funnel configured to guide the proximal end of the penetrating member toward the center of the distal stop member. The transfer member can include a radially extending member configured to physically interfere with the funnel and, upon contact with the funnel, stop proximal movement of the transfer member relative to the funnel and the distal stop member. The penetrating member can include a geometric feature at its proximal end. The geometric feature can be configured to penetrate the distal stop member.

[0019] In one or more embodiments, the distal exit tube includes a split-open distal end. The distal exit tube can include a proximal opening and a proximal end opening. The penetrating member can be longer than the distance between the proximal opening and the proximal end opening. The system can include a ring welded to the distal exit tube. The ring can be configured to prevent the distal end of the distal exit tube from extending more than a predetermined distance toward the distal end of the distal needle interface.

[0020] In one or more embodiments, the system has a delivery configuration, a transfer configuration, and a mixing configuration. In the delivery configuration, the piercing member is disposed completely within the distal drug chamber. In the transfer configuration, the piercing member at least partially penetrates the distal stop member, and the piercing member and the transfer member are at least partially disposed within the proximal drug chamber. In the mixing configuration, the proximal stop member and the distal stop member contact each other, thereby transferring a first drug component from the proximal drug chamber to the distal drug chamber and mixing the first drug component with a second drug component in the distal drug chamber. A fluid passage can form a fluid pathway between the proximal and distal chambers when the system is in the delivery configuration. The transfer member may not completely penetrate the proximal stop member when in the mixing configuration or during injection. After the system reaches the mixing configuration, the distal outlet tube presses in like a wedge to open the transfer member and slides proximally within the transfer member with further distal movement of the distal stop member.

[0021] In one or more embodiments, the system is configured to convert from the delivery configuration to the transfer configuration by applying a preset force to the distal stopper member. The preset force is a distally directed force of approximately 3-5 lbf. The distal outlet tube can include a distal opening at its distal end and a proximal opening disposed within the distal drug chamber. The first and second sizes of the proximal and distal drug chambers, respectively, can be changed by moving the proximal and distal stopper members relative to the syringe body. The proximal and distal drug chambers can contain first and second drug components, respectively, that are mixed together prior to injection into a patient. The transfer member can be formed from a metal or a polymer.

[0022] In one or more embodiments, the transfer member includes a latch having a latched state and an unlatched state. In the latched state, the latch prevents axial movement of the penetrating member and the distal exit tube relative to the transfer member, and in the unlatched state, the latch allows axial movement of the penetrating member and the distal exit tube relative to the transfer member. The latch can include a plastic hinge. The plastic hinge can open to convert the latch from the latched state to the unlatched state. The plastic hinge can open in response to application of a preset amount of force to the latch. The preset amount of force can be a distally directed force of about 6 lbf to about 10 lbf. The latch can include a frangible link for holding the transfer member in the latched state until a preset amount of force is applied to the latch. The preset amount of force can be a distally directed force of about 6 lbf to about 10 lbf.

[0023] In another embodiment, a syringe modification device includes a fluid transfer assembly. The fluid transfer assembly includes a piercing member configured to pierce a distal stop member of the syringe to fluidly couple the proximal and distal drug chambers of the syringe. The fluid transfer assembly also includes a distal outlet tube configured to couple to a proximal end of a needle of the syringe, the distal end of the piercing member being disposed within the distal outlet tube. The fluid transfer assembly further includes a transfer member disposed adjacent to at least a portion of the piercing member, the distal transfer member defining a fluid passageway configured to fluidly couple the distal drug chamber and the proximal drug chamber upon penetration of the distal stop member by the piercing member. The distal outlet tube may include a slot configured to couple the distal outlet tube to the proximal end of the needle.

[0024] In yet another embodiment, an injection system includes a syringe body defining a proximal opening at a proximal end and a distal needle interface at a distal end. The system also includes a proximal stop member and a distal stop member disposed within the syringe body, forming a proximal drug chamber between the proximal stop member and the distal stop member, and a distal drug chamber between the distal stop member and the distal end of the syringe body. The system further includes a plunger member configured to be manually operated to insert the proximal stop member relative to the syringe body. The system further includes a fluid transfer assembly. The system further includes a finger flange including an anti-backup mechanism. The anti-backup mechanism has a brake tab configured to apply a counterforce to the plunger member to prevent proximal movement thereof relative to the brake tab and a retention feature configured to maintain the anti-backup mechanism in a recess in the finger flange.

[0025] In one or more embodiments, the finger flange also includes a separate recess configured to attach the finger flange to the flange of the syringe body. The anti-backup feature can also include a plurality of fit tabs configured to reduce the tolerance between the dimensions of the recess and the anti-backup feature. The anti-backup feature can be a metal clip.

[0026] In one or more embodiments, the brake tab is a resilient, self-actuating pawl. The brake tab can be positioned at an acute angle distally relative to the plane of the anti-backup mechanism. The acute angle and resilience of the brake tab can increase the frictional force against the plunger member during proximal retraction. The acute angle of the brake tab also creates a reaction force parallel to the plunger member exerted by the sharp, curved edge of the brake tab contacting the surface of the plunger member. This force prevents proximal movement of the plunger member. The acute angle and resilience of the brake tab also enable the brake tab to exert an outward force against the inner wall of the finger flange via the anti-backup mechanism when the plunger member is retracted proximally.

[0027] In one or more embodiments, the finger flange also includes an opening having an edge configured to interfere with the anti-backup feature to retain the anti-backup feature within the recess. The anti-backup feature can have a "C" or "O" shape. The anti-backup feature can prevent removal of the plunger member from the syringe body after the plunger member has been inserted into the syringe body. The opposing force can include a friction force and a reaction force.

[0028] In yet another embodiment, an injection system includes a syringe body defining a proximal opening at a proximal end and a distal needle interface at a distal end. The system also includes proximal and distal stop members disposed within the syringe body, forming a proximal chamber between the proximal and distal stop members and a distal chamber between the distal stop member and the distal end of the syringe body. The system further includes a plunger member configured to be manually manipulated to insert the stop member relative to the syringe body. The system further includes a fluid transfer assembly. The fluid transfer assembly includes a penetration tube configured to penetrate the distal stop member. The assembly also includes a solid elongated member, with the penetration tube at least partially disposed around a portion of the solid elongated member. The assembly further includes a distal tube, with the distal end of the solid elongated member disposed at the proximal end of the distal tube. The penetration tube includes a pair of vacuum stoppers configured to increase the force required for the proximal end of the penetration tube to fully penetrate the distal stop member. After the proximal end of the through tube passes completely through the distal stop member, the through tube defines a fluid passageway between the proximal and distal chambers.

[0029] In one or more embodiments, each of the vacuum stops includes a tab extending radially outward in a distal direction. The distal stop member can also include a funnel insert disposed in the distal stop member configured to interfere with the vacuum stop of the through tube to stop proximal movement of the through tube relative to the funnel insert and the distal stop member when the radially extending member contacts the funnel insert. The funnel insert can be configured to guide the proximal end of the through tube toward the center of the distal stop member.

[0030] In one or more embodiments, the through tube further includes a tubular member and a disk disposed at a distal end thereof perpendicular to the longitudinal axis of the tubular member. The disk can define a plurality of radially inwardly extending stops connecting the disk to the tubular member. The plurality of radially inwardly extending stops can define an adjustable opening approximately in the center of the disk. The adjustable opening can have a small configuration configured to prevent a solid elongated member from passing completely through the disk and through tube, and a large configuration configured to allow the solid elongated member to pass completely through the disk and through tube.

[0031] In one or more embodiments, the distal tube has a proximally facing shoulder at its proximal end configured to interfere with a plurality of radially inwardly extending stops to prevent proximal movement of the distal tube relative to the through tube when the adjustable opening is in the small configuration. The diameter of the adjustable opening in the small configuration may be smaller than the outer diameter of the shoulder. The diameter of the adjustable opening in the large configuration may be larger than the outer diameter of the shoulder. Proximal movement of the tubular member away from the disk may change the adjustable opening from the small configuration to the large configuration. Distal movement of the disk away from the tubular member may change the adjustable opening from the small configuration to the large configuration.

[0032] In one or more embodiments, the adjustable opening is transformed from the small configuration to the large configuration by application of a proximally directed force of a predetermined magnitude to the through tube provided by fluid pressure from the plunger member to the distal stop member. The proximally directed force of the predetermined magnitude can be about 7.5 lbf to about 10 lbf. A tubular member extending through the distal stop member can apply a radially inward force to the plurality of radially inwardly extending stoppers to hold the adjustable opening in the small configuration.

[0033] In one or more embodiments, the through tube further includes a pair of radially inward, proximally extending tabs configured to limit distal movement of the solid elongate member relative to the through tube. The solid elongate member can include a distally facing shoulder configured to interfere with the radially inward, proximally extending tabs to limit distal movement of the solid elongate member relative to the through tube.

[0034] In one or more embodiments, the through-tube defines a proximal end opening, an intermediate opening, and a distal opening. After the proximal end of the through-tube fully penetrates the distal stopper member, the fluid passage between the proximal chamber and the distal chamber includes the proximal end opening, the intermediate opening, and the distal opening. The system can also include a vacuum in the distal chamber. The through-tube can include a chamfered corner at its proximal end.

[0035] In one or more embodiments, the system has a delivery configuration, a transfer configuration, and a mixing configuration. In the delivery configuration, the through-tube is disposed entirely within the distal chamber and the distal stopper member. In the delivery configuration, the through-tube partially penetrates the distal stopper member and the open proximal end of the through-tube is disposed within the proximal chamber. In the mixing configuration, the proximal and distal stopper members contact each other, thereby transferring a first drug component from the proximal chamber to the distal chamber and mixing the first drug component with a second drug component in the distal chamber. The through-tube can form a fluid pathway between the proximal and distal chambers when the system is in the delivery configuration. The through-tube can also not completely penetrate the distal stopper member. After the system reaches the mixing configuration, the solid elongate member can be released from the through-tube by further distal movement of the distal stopper member. The system can be converted from the delivery configuration to the transfer configuration by applying a predetermined amount of force to the distal stopper member. The preset force magnitude can be a distally directed force of about 7.5 lbf to about 10 lbf. The proximal and distal chambers can contain first and second components, respectively, of a medication that are mixed together prior to injection into a patient.

[0036] These and other embodiments of the present invention are described in the detailed description that follows. [Brief explanation of the drawings]

[0037] The above and other aspects of the embodiments are described in further detail with reference to the accompanying drawings, in which like elements in various figures are designated by common reference numerals.

[0038] [Figure 1] 1A and 1B show various aspects of conventional injection syringe configurations. [Figure 2] 2A and 2B show various aspects of conventional injection syringe configurations. [Figure 3] FIG. 3 shows various aspects of conventional injection syringe configurations. [Figure 4] 4A and 4B show various aspects of conventional injection syringe configurations. [Figure 5] 5A-5C show various aspects of conventional injection syringe configurations. [Figure 6] 6A and 6B show various aspects of a syringe-based dual chamber safety injection system in which the end / tip of the distal needle retracts into a protective configuration after use, according to some embodiments. [Figure 7] 7A-7P illustrate various aspects of a syringe-based dual chamber safety injection system during steps of a method for mixing and injecting using the system, according to some embodiments. [Figure 8] FIG. 8 illustrates a dual chamber injection system according to some embodiments. [Figure 9] FIG. 9 illustrates a dual chamber injection system according to some embodiments. [Figure 10] FIG. 10 illustrates components of a fluid transfer assembly for use in a dual chamber injection system according to some embodiments. [Figure 11] FIG. 11 illustrates the assembly of components of a fluid transfer assembly for use in a dual chamber injection system according to some embodiments. [Figure 12] FIG. 12 illustrates the assembly of components of a fluid transfer assembly for use in a dual chamber injection system according to some embodiments. [Figure 13] FIG. 13 illustrates the assembly of components of a fluid transfer assembly for use in a dual chamber injection system according to some embodiments. [Figure 14] FIG. 14 illustrates the assembly of components of a fluid transfer assembly for use in a dual chamber injection system according to some embodiments. [Figure 15] FIG. 15 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 16] FIG. 16 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 17] FIG. 17 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 18] FIG. 18 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 19] FIG. 19 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 20] FIG. 20 illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. [Figure 21] Figure 21A illustrates a fluid transfer assembly in a dual chamber injection system according to some embodiments. Figures 21B-21E illustrate a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 22] FIG. 22 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 23] FIG. 23 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 24] FIG. 24 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 25] FIG. 25 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 26] FIG. 26 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 27] FIG. 27 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 28] FIG. 28 illustrates a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 29] 29A-29H illustrate a fluid transfer assembly and its components for use in a dual chamber injection system according to some embodiments. [Figure 30] FIG. 30 shows a fluid transfer assembly that may form part of a dual chamber injection system conversion kit. [Figure 31] FIG. 31 illustrates a dual chamber injection system conversion kit according to some embodiments and its use in converting a single chamber injection system to a dual chamber injection system. [Figure 32] FIG. 32 illustrates a dual chamber injection system conversion kit according to some embodiments and its use in converting a single chamber injection system to a dual chamber injection system. [Figure 33] FIG. 33 illustrates a dual chamber injection system conversion kit according to some embodiments and its use in converting a single chamber injection system to a dual chamber injection system. [Figure 34] FIG. 34 illustrates a dual chamber injection system conversion kit according to some embodiments and its use in converting a single chamber injection system to a dual chamber injection system. [Figure 35] FIG. 35 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 36] FIG. 36 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 37]FIG. 37 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 38] FIG. 38 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 39] FIG. 39 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 40] FIG. 40 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 41] FIG. 41 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 42] FIG. 42 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 43] FIG. 43 illustrates an anti-backup mechanism for use in a dual chamber injection system according to some embodiments. [Figure 44] 44A-44F show a needle hub assembly with a resilient needle latch for use in a safe needle retraction injection system according to some embodiments. [Figure 45] 45A-45D show a needle hub assembly having an elastomeric needle retention system for use in a safe needle retraction injection system according to some embodiments. [Figure 46] 46A-46E illustrate an injection system having a needle hub attachment mechanism according to some embodiments. [Figure 47] 47A-47H illustrate an injection system having a needle hub attachment mechanism according to some embodiments. [Figure 48] FIG. 48 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 49]FIG. 49 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 50] FIG. 50 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 51] FIG. 51 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 52] FIG. 52 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 53] FIG. 53 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 54] FIG. 54 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 55] FIG. 55 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 56] FIG. 56 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 57] FIG. 57 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 58] FIG. 58 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 59] FIG. 59 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 60]FIG. 60 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 61] FIG. 61 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 62] FIG. 62 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments. [Figure 63] FIG. 63 illustrates a dual chamber injection system including a fluid transfer assembly and components thereof according to some embodiments.

[0039] To better understand how the above and other advantages and objects of the various embodiments are obtained, a more detailed description of the embodiments will be provided with reference to the accompanying drawings. It should be noted that the drawings are not drawn to scale, and elements of similar structure or function are designated by similar reference numerals throughout. It should be understood that the drawings depict only certain exemplary embodiments, and therefore should not be considered to limit the scope of the embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0040] Exemplary Prefilled Dual Chamber Safety Infusion System 6A and 6B, a perspective view and a longitudinal cross-sectional view of a pre-filled dual-chamber safety injection system (100) are shown, each having a conventional pre-filled syringe body (34) with conventional proximal and distal stop members (32, 36) disposed therein. The proximal and distal stop members (32, 36), together with the syringe body (34), define proximal and distal chambers (40, 42). The proximal and distal stop members (36, 37) occlude the proximal and distal ends of the proximal chamber (40). The distal stop member (36) occludes the proximal end of the distal chamber (42). In some embodiments, the distal end of the proximal stopper member (32) and the proximal end of the distal stopper member (36) can be coated with a lubricious polymer coating (e.g., PTFE), and the first and second polymer coatings of the proximal and distal stopper members (32, 36), together with the syringe body (34), define a proximal chamber (40). The lubricious polymer coating serves to isolate the rubber of the proximal and distal stopper members (32, 36) from the second liquid (254). The proximal and distal stopper members (32, 36) can be oriented as shown in FIGS. 6A and 6B, or the distal stopper (36) can be inverted so that the lubricious coating faces the distal chamber (42) and the first liquid (252) in the distal chamber (42) contacts the lubricious coating for storage.

[0041] The needle coupling assembly (606) is disposed at the distal end of the distal chamber (42) with the needle cover member (63) attached for storage. The dual-chamber safety injection system facilitates sequential injection of a first liquid (252) from the distal chamber (42) followed by a second liquid (254) from the proximal chamber by a user sequentially inserting the plunger assembly (44) into the syringe body (34) to varying degrees. The plunger assembly (44) includes a proximal stopper member (32), a plunger housing member (69), and a plunger operating interface (128). The first and second liquids disposed in the distal and proximal chambers (42, 40), respectively, may be any liquid or gel, such as an aqueous or oil-based medicinal solution.

[0042] The dual-chamber safety injection system (100) has a staked needle configuration in which, when provided to a user, the needle assembly, including the needle spine assembly ("needle") (76) and the needle coupling assembly (606), is mounted in a fixed position ready for injection after removal of the needle cover member (63), which may have an elastomeric sealing material on its interior surface that contacts the needle distal end (78) and / or distal housing portion during storage. Alternatively, the needle cover member (63) may include a vent (not shown) that allows pressure resulting from the movement of the liquids (252, 254) to escape from the interior of the syringe body (34) while preventing contamination from entering the syringe body (34). Although the staked needle is depicted as being fixed in place, the staked needle can be removably coupled to the syringe body (34) using a luer slip or luer lock interface (not shown), with the proximal end (50) of the needle member extending through the luer interface into the distal chamber (42). Alternatively, the needle may be fixedly or removably attached to a flange on the cartridge body instead of the syringe. In the embodiment shown in Figures 6A and 6B, a significant portion of the safety needle retraction member resides within the plunger housing.

[0043] 7A-7P, various embodiments of configurations designed to facilitate injection of a multi-component drug and retraction of a needle into a syringe body are illustrated, in which two or more drug components are combined to form an injection combination or solution immediately prior to delivery to a patient. In one embodiment, a liquid first drug component / diluent (252) can be combined with a substantially non-liquid second drug component (254), such as a powder form of the drug, such as a lyophilized drug component, immediately prior to injection. The configurations described herein with reference to FIGS. 7A-7P relate to dual-chamber configurations, in which two or more chambers within the same syringe body (34) are utilized for transport, mixing, and injection of the injection solution.

[0044] 7A and 7B, a distal stopper member (36) between two interior portions of a syringe body (34) defines proximal and distal medicament chambers (40, 42), with the distal medicament chamber (42) containing an air or gas gap and a non-liquid medicament (254), and the proximal medicament chamber (40), opposite the distal stopper member (36), containing a liquid diluent (252) that is confined proximally by the proximal stopper member (32). The liquid diluent (252) is a first component of the medicament, and the non-liquid medicament (254) is a second component of the medicament.

[0045] Referring to Figure 7C and the associated cross-sectional view in Figure 7D, various components of the needle coupling assembly (here, a so-called "staked" needle coupling assembly 606 is illustrated, although other needle assemblies, as described below, including Luer coupling configurations as well as staked configurations, can be utilized). Lug feature 258 is configured to assist in coupling the needle coupling assembly 606 to the needle cover member 63, as shown, for example, in Figure 7A. A small O-ring can be utilized as the sealing member 260 around the needle shaft, while a large O-ring can be utilized as the sealing member 262 at the syringe body 34 / needle coupling assembly 606 interface. Alternatively, the small O-ring 260 and the large O-ring 262 can be combined into a single seal that performs both O-ring sealing functions. The small O-ring 260 can also be used to seal both around the needle shaft and with the syringe body 34.

[0046] The needle includes multiple (e.g., four) proximal openings / ports (270) configured to allow the inflow of liquid diluent that exits through a more distally located intermediate opening / opening (266), and a lumen plug (268) occludes the needle lumen to create a flow path from the proximal openings (270) to the intermediate openings (266) under conditions such as those described above with reference to Figures 6N and 7H. The needle also includes a distal opening (264) on the opposite side of the lumen plug (268) from the intermediate openings (266). The distal opening (264) is fluidly coupled to the needle distal end (48) through the needle for injecting liquid into a patient.

[0047] Referring to Figure 7E, a proximal harpoon interface (84) is configured to serially pierce the proximal and distal stop members (32, 36) and mate with a coupling feature in the plunger rod (such as a needle retaining feature, for example, as illustrated in Figures 7N and 7P (element 712)). Figure 7F shows a spike-type harpoon coupling interface (85) configured to serially pierce both the proximal and distal stop members (32, 36) and mate with a coupling feature in the plunger rod to at least partially retract the needle member into the plunger rod after an injection has been administered to the patient.

[0048] Figures 7A, 7B, and 7G-7P illustrate a sequence of actions for an injection procedure utilizing a dual-chamber safety injection system as described above. Referring to Figures 7A and 7B, the injection assembly is in a stable configuration, ready for shipment or injection patient care scenario, with the first pharmaceutical component / liquid diluent (252) separated from the second, non-liquid pharmaceutical component (254), both within the syringe body and located on opposite sides of the distal stopper member (36).

[0049] 7G and 7H illustrate the initial insertion of plunger assembly (44), advancing distal (36) and proximal (32) stop members together relative to syringe body (34). Referring to FIG. 7H, advancement sufficient to pierce proximal end (50) of needle assembly and traverse distal stop member (36) creates a fluid pathway between the two previously separated chambers (40, 42) of syringe body (34), allowing liquid first drug component (252) in proximal drug chamber (40) to flow through transfer tube (46), into at least one of proximal openings (270), and out the more distal intermediate opening (266) to reach non-liquid second drug component (254) in distal drug chamber (42).

[0050] Figures 7I and 7J show that upon further insertion of the stopper members (36, 32) adjacent one another, the liquid first drug component / diluent (252) moves into the distal drug chamber (42) and merges with the non-liquid second drug component (254). Figures 7K and 7L show that over time and / or with manual agitation, the liquid first drug component / diluent (252) and the formerly non-liquid second drug component (254) mix to form a mixed drug solution (272).

[0051] In some embodiments, particularly with a lyophilized, non-liquid second drug component, the mixed drug solution (272) can be formed with minimal or no agitation or time lapse. In other embodiments, particularly with drugs held in suspension or emulsified drugs, vigorous shaking may be required to promote mixing. The user may find it convenient to remove their thumb from the plunger operating interface (128) during vigorous shaking. During the transfer of the liquid first drug component (252) from the proximal drug chamber to the distal drug chamber (40, 42), pressure may build up in the distal drug chamber (42). This pressure acts on the proximal and distal stopper members (32, 36) to resist stopper movement. Furthermore, if the user does not restrain the plunger assembly (44) with their thumb, the pressure buildup may cause the stopper members (32, 36) and plunger operating interface (128) to move proximally. A mixing configuration latch or "mixing click" on the plunger assembly (44) can be utilized to provide resistance to movement of the plunger operating interface (128) due to pressure buildup, allowing the user to remove their thumb from the plunger operating interface (128) for shaking or mixing the medication. The mixing click can also be an audible and / or tactile indication that transfer of the liquid first medication component (252) is complete. The distal medication chamber (42) can also include an agitation device to assist in mixing the medication components.

[0052] With the assembly ready for injection of the mixed solution (272), as shown in Figures 7M and 7N, the needle cover member (63) can be removed and the plunger assembly (44) and associated stop members (36, 32) can be depressed / inserted to expose the needle distal end (48) for injection into a patient. Referring to Figures 7O and 7P, full depression / insertion of the plunger assembly (44) and associated stop members (32, 36) can automatically retract the sharp needle distal end / tip (48) at least partially through the distal and proximal stop members (36, 32) to a safe position within the syringe body (34), needle coupling assembly (606), or at least partially within the plunger assembly (44).

[0053] Exemplary Fluid Transfer Assembly for a Dual Chamber Safety Injection System FIG. 8 illustrates a dual-chamber injection system 800 including a fluid transfer assembly configured to provide precise control of the handling, mixing, and delivery of components of a multi-component injectate, according to some embodiments. Similar to the dual-chamber injection system 100 illustrated in FIGS. 6A-7B and 7G-7P, the dual-chamber injection system 800 includes a syringe body 810, proximal and distal stopper members 812, 814, and a plunger member 816. The plunger member 816 is inserted into an interior 818 of the syringe body 810 through a proximal opening in the syringe body. The syringe body 810 also includes a distal needle interface 820 at its distal end. While the dual-chamber injection system 100 illustrated in FIGS. 6A-7B and 7G-7P includes a staked needle, the syringe body 810 includes a Luer lock-type distal needle interface 820. The distal needle interface 820 is not limited to a Luer lock and may be another type of needle / tubing interface. The proximal and distal stop members 812, 814, together with the syringe body 810, define a proximal drug chamber 822. The distal stop member 814 and the syringe body 810 define a distal drug chamber 824. The plunger member 816 can be manually manipulated to insert the proximal stop member 812 relative to the syringe body 810. When an incompressible fluid is disposed in the proximal drug chamber 822, inserting the proximal stop member 812 also inserts the distal stop member 814 relative to the syringe body 810.

[0054] While the dual-chamber injection system 100 shown in Figures 6A-7B and 7G-7P has a needle with various openings for fluid transfer and delivery (see Figures 7C-7F), the dual-chamber injection system 800 includes a fluid transfer assembly 830 for fluid transfer and delivery.

[0055] As shown in FIG. 9 , a fluid transfer assembly 830 according to some embodiments includes a piercing member 840, a distal outlet tube 850, and a transfer member 860. The piercing member 840 is partially disposed within the distal outlet tube 850 and partially disposed within the transfer member 860. The distal outlet tube 850 is generally an elongated tubular member that includes a jam ring 852 welded thereon to prevent distal movement of the distal outlet tube 850 during use of the dual-chamber injection system 800. The position of the jam ring 852 on the distal outlet tube is configured to leave a seal clearance 853 between the distal end of the distal outlet tube and the distal end of the syringe body 810. The seal clearance 853 prevents the syringe cap from leaking during storage and shipping.

[0056] FIG. 10 illustrates the penetrating member 840 inserted into the distal outlet tube 850, with the overlying transfer member 860 omitted for clarity, according to some embodiments. The joint 842 between the penetrating member 840 and the distal outlet tube 850 is welded to form a watertight seal 842 that prevents unintended fluid flow. The penetrating member 840 is generally an elongated solid member that includes a geometric feature 844 at its proximal end. The geometric feature 844 shown in FIG. 10 has a three-dimensional arrowhead shape configured to penetrate the distal stop member 814. The outer diameter of the penetrating member 840, excluding the geometric feature 844, is substantially consistent and configured to fit snugly inside the distal outlet tube 850. That is, the outer diameter of the penetrating member 840 is slightly smaller than the inner diameter of the distal outlet tube 850.

[0057] The distal end of geometric feature 844 has an outer dimension / diameter that is larger than the outer diameter of penetrating member 840. The proximal end of distal exit tube 850 also has an outer dimension / diameter that is larger than the outer diameter of penetrating member 840. Thus, the distal end of geometric feature 844 and the proximal end of distal exit tube 850 form proximal and distal shoulders 846, 854 that surround annular recessed portion 848 of penetrating member 840. Annular recessed portion 848 is sized and shaped to retain the transfer member in a closed configuration (described below).

[0058] The piercing member 840 has a length sufficient to substantially fill the interior of the distal outlet tube 850 between the proximal opening / junction / watertight seal 842 and a side opening 856 formed in the side wall of the distal outlet tube 850 near the jam ring 852. In the embodiment shown in FIG. 10 , the distal end of the piercing member 840 extends to a point X adjacent to and near the side opening 856. In addition to filling the interior of the distal outlet tube 850 between the proximal opening 842 and the side opening 856, the piercing member 840 has an additional length sufficient to form an annular recessed portion 848.

[0059] The distal outlet tube includes a distal opening with a split end 858 and is hollow between the side opening 856 and the distal opening 858. The distal tube between the side opening 856 and the distal opening 858 forms a flow path Y through which fluid can exit the distal drug chamber and exit through the distal opening 858. The split end at the distal opening 858 is configured to couple the distal outlet tube 850 to a tubular member that forms a distal outlet from the dual-chamber infusion system 800. Exemplary tubular members include, but are not limited to, a needle and a tube, both of which may be attached to a Luer connector.

[0060] 11-14 illustrate a transfer member 860 attached to the annular recessed portion 848 of the piercing member 840, according to some embodiments. FIG. 11 shows the transfer member 860 before attachment. The transfer member 860 may be cut from a metal sheet. The transfer member 860 includes two plastic / living hinges 862 and a longitudinal opening 864 sized and shaped to facilitate conversion of the transfer member 860 between a closed configuration and an open configuration (described below). The plastic / living hinges 862 and the longitudinal opening 864 can be modified to adjust the retention force of the transfer member 860 relative to the piercing member 840. The transfer member 860 also includes a funnel 866 at its distal end. The transfer member 860 further includes two radially extending members 868, each in the form of a wing configured to interfere with the distal stop member 814 and prevent distal movement of the distal stop member 814 relative to the transfer member 860.

[0061] 12 shows the relative positions of the piercing member 840 (which is already coupled to the distal exit member 850) and the transfer member 860 before the fluid transfer assembly 830 is assembled. The transfer member 860 is aligned with the annular recessed portion 848 of the piercing member 840.

[0062] FIG. 13 shows the piercing member 840 and the transfer member 860 being moved toward each other such that the transfer member 860 is positioned over the annular recessed portion 848 of the piercing member 840 .

[0063] 14 illustrates crimping of transfer member 860 around annular recessed portion 848 of penetrating member 840. Crimping can be performed manually or mechanically / robotically. Crimping transfer member 860 seats transfer member 860 in annular recessed portion 848 of penetrating member 840. Once seated, transfer member 860 assumes its closed configuration. In the closed configuration, proximal shoulder 846 interferes with the proximal end of transfer member 860, preventing distal movement of penetrating member 840 relative to transfer member 860. Additionally, in the closed configuration, distal shoulder 854 interferes with funnel 866 at the distal end of transfer member 860, preventing proximal movement of penetrating member 840 relative to transfer member 860.

[0064] With the transfer member 860 in the closed configuration shown in FIG. 14 and seated in the annular recessed portion 848 of the penetrating member 840, the fluid transfer assembly 830 can be assembled with the other components of the dual chamber injection system 800.

[0065] 15 shows an exploded view of selected components of a dual-chamber injection system 800 according to some embodiments. The assembled fluid transfer assembly 830 is inserted through the proximal opening of the syringe body 810 until the jam ring 852 interferes with the distal end of the syringe body 810, preventing further distal movement of the fluid transfer assembly 830 relative to the syringe body 810. The distal stop member 814 includes a guide / funnel 813 configured to direct the geometric feature 844 at the proximal end of the penetrating member 840 toward the center of the distal stop member 814. The distal stop member 814, including the guide / funnel 813, is then inserted through the proximal opening of the syringe body 810 until the geometric feature 844 at the proximal end of the penetrating member 840 abuts the center of the guide / funnel 813 adjacent to the center of the distal stop member 814. Insertion of the distal stop member 814 defines the distal drug chamber 824. Next, a proximal stop member 812 is inserted through the proximal opening of the syringe body 810, thereby defining a proximal drug chamber 824 (see FIG. 8). Thereafter, a plunger member 816 is inserted through the proximal opening of the syringe body 810 and coupled to the proximal stop member 812 (e.g., by threading the plunger member 816 onto the proximal stop member 812; see FIG. 8).

[0066] FIG. 16 illustrates a dual-chamber injection system 800 in an as-shipped / shipped configuration according to some embodiments. In the as-shipped / shipped configuration, the proximal end of the geometric feature 844 of the penetrating member 840 remains centered within the guide / funnel 813 and the distal stop member 814, respectively. The proximal end of the geometric feature 844 resides on the inner surface of the distal stop member 814 and is ready to penetrate the distal stop member 814 in response to a distally directed force applied to the distal stop member 814. In the as-shipped / shipped configuration, the proximal and distal drug chambers 822, 824 are isolated from each other, and any drug components contained therein are also isolated from each other. Furthermore, any drug components contained in the proximal drug chamber 822 are exposed only to the glass side of the syringe body 810, the proximal and distal stop members 812, 814, thereby facilitating the delivery of metal-sensitive drug components within the proximal drug chamber 822.

[0067] FIG. 17 illustrates a dual-chamber injection system 800 in a transfer configuration according to some embodiments. In the transfer configuration, a geometric feature 844 penetrates the distal stop member 814 in response to a distally directed force applied to the distal stop member 814 (e.g., a force originally applied via the plunger member 816, the proximal stop member 812, and the incompressible fluid in the proximal drug chamber 822). The magnitude of the distally directed force required to drive the geometric feature 844 through the distal stop member 814 can be about 3 lbf to about 5 lbf. In the transfer configuration, a proximal end of a transfer member 860 is disposed within the proximal drug chamber 822. The transfer member 860 defines a fluid passageway (e.g., a trench) 861 above the annular recessed portion 848 (see FIGS. 10 and 14) of the penetrating member 840. In the transfer configuration, fluid passageway 861 is the fluid flow path between the proximal and distal drug chambers 822, 824. Thus, increased pressure in proximal drug chamber 822, which may be provided by distal movement of plunger member 816 and associated proximal stopper member 812, causes fluid to be transferred from proximal drug chamber 822 to distal drug chamber 824. Transfer member 860 also includes chamfered corners and its proximal end configured to reduce resistance to the flow of liquid through fluid passageway 861.

[0068] In the transfer configuration, a user can apply a distally directed force to plunger member 816 to transfer the liquid drug component in proximal drug chamber 822 to distal drug chamber 824 and solubilize the powdered drug component therein. The liquid drug component is transferred through a fluid passageway 861 formed in distal stopper member 814 by transfer member 860 of fluid transfer assembly 830.

[0069] 18 illustrates forces acting on the transfer member 860 during complete penetration of the fluid transfer assembly 830, guided by the geometric feature 844, through the distal stop member 814 (see FIG. 17), according to some embodiments. During insertion of the fluid transfer assembly 830 through the distal stop member 814, friction of the distal stop member material exerts a distally directed force F1 on the transfer member 860. However, the distally directed force F1 is counteracted by a reaction force F2 generated by interference between the funnel 866 at the distal end of the transfer member 860 and the distal shoulder 854. The balance of forces F1 and F2 causes the transfer member 860 to remain within the annular recessed portion 848 (see FIGS. 10 and 14) of the penetration member 840 as the fluid transfer assembly 830 penetrates the distal stop member 814. The distal stopper member 814 and the geometric feature 844 are configured so that the force exerted by the distal stopper member 814 on the geometric feature 844 required to cause the fluid transfer assembly 830 to penetrate the distal stopper member 814 is approximately 3 lbf to approximately 5 lbf.

[0070] 19 illustrates the dual-chamber injection system 800 according to some embodiments after it has reached the mixing configuration. In the mixing configuration, the proximal stopper member 812 is advanced distally so that the proximal and distal stopper members 812, 814 contact one another, thereby substantially collapsing the proximal drug chamber 822. In the mixing configuration, any liquid drug components in the proximal drug chamber 822 have been transferred to the distal drug chamber 824 through the fluid passageway 861 formed in the distal stopper member 814 by the transfer member 860. At that point, the dual-chamber injection system 800 can be agitated (e.g., by inversion) to mix the drug components in the distal drug chamber 824. After the drug components have been mixed, the multi-component injectate is ready for delivery / injection.

[0071] After the dual chamber injection system 800 reaches the mixed configuration, further application of a distally directed force to the plunger member 816 pushes the proximal and distal stop members 812, 814 distally relative to the penetrating member 840 (see FIG. 18 ). Initially, the distally directed force causes the proximal and distal stop members 812, 814 to move distally relative to the transfer member 860. However, as the distal stop member 814 moves distally relative to the transfer member 860, the radially extending members / wings 868 abut the inner surface of the guide / funnel 813, thereby preventing further distal movement of the distal stop member 814 (see FIGS. 19 and 20 ) relative to the transfer member 860. The interference between the radially extending members / wings 868 and the guide / funnel 813 allows additional force to be applied to the transfer member 860 by the guide / funnel 813. This additional force (i.e., about 6 lbf to about 10 lbf) is sufficient to transform the transfer member 860 from the closed configuration (see FIG. 18) to the open configuration shown in FIG. 20. When the magnitude of the distally directed force reaches about 6 lbf to about 10 lbf, the distal shoulder 854 formed by the proximal end of the distal outlet tube 850 wedges against the funnel 866 at the distal end of the transfer member 860, thereby opening the tubular transfer member 860. As the transfer member 860 is wedged open, it changes from its closed configuration to its open configuration.

[0072] With the transfer member 860 in the open configuration, the distal outlet tube 850 and the coupled piercing member 840 can move proximally relative to the proximal and distal stop members 812, 814. Such distal movement causes the piercing member 840 to penetrate the proximal stop member 812. Because the transfer member 860 penetrates only the distal stop member 814 and not the proximal stop member 812, there is no fluid leakage path to the plunger member 816. The proximal stop member 812 will seal around the piercing member 840 and distal outlet tube 850 as they penetrate the proximal stop member 812.

[0073] 20 illustrates the relative positions of the guide / funnel 813 within the fluid transfer assembly 830 and the distal stop member (not shown for clarity) after the dual chamber injection system 800 according to some embodiments has reached the mixed configuration and the transfer member 860 has reached the open configuration. The radially extending members / wings 868 of the transfer member 860 interfere with the guide / funnel 813 to prevent distal movement of the guide / funnel 813 and distal stop member 814 relative to the transfer member 860.

[0074] 21A illustrates a fluid transfer assembly 830 with the transfer member 860 in an open configuration, according to some embodiments. The guide / funnel 813 and distal stop member are omitted for clarity. The dual-chamber injection system 800 has moved beyond the mixed configuration by expelling a portion of the mixed multi-component infusate from the dual-chamber injection system 800. As described above, the distal shoulder 868 formed by the proximal end of the distal outlet tube 850 wedges through the funnel 866 at the distal end of the transfer member 860, placing the transfer member 860 in the open configuration. With the transfer member 860 in the open configuration, the transfer member 860 can move proximally relative to the distal outlet tube 850.

[0075] 21B-21E illustrate a fluid transfer assembly 2130 (see FIG. 21E) according to some embodiments. The fluid transfer assembly 2130 includes a piercing member 2140, a distal exit tube 2150, and a transfer member 2160. The piercing member 2140 and the distal exit tube 2150 are similar to the piercing member 840 and the distal exit tube 850 shown in FIGS. 7-21A and described above. One difference is that the piercing member 2140 in FIG. 21E is shorter than the piercing member 840 shown in FIGS. 7-21A. The shorter length of the piercing member is to accommodate the transfer member 2160, which will be described later.

[0076] 21B-21D show transfer member 2160 in top, side, and perspective views. Transfer member 2160 in FIGS. 21B-21D is similar to transfer member 860 in FIG. 11. For example, transfer member 2160 has a plastic hinge 2162, a longitudinal opening 2164, and a pair of radially extending members / wings 2168. These components of transfer member 2160 are generally identical to the corresponding components in transfer member 860 described above. One difference between transfer members 2160 and 860 is that transfer member 2160 shown in FIGS. 21B-21D does not have a funnel / guide at its distal end, such as funnel / guide 866 at the distal end of transfer member 860 shown in FIG. 11. Another difference is that the transfer member 2160 shown in Figures 21B-21D has a pair of detents 2166 at its proximal end configured to interfere with the distal shoulder 2154 formed at the proximal end of the distal outlet tube 2150 (see Figure 21E).

[0077] The detent 2166 is configured to prevent proximal movement of the distal exit tube 2150 and the associated piercing member 2140 relative to the transfer member 2160 when the transfer member 2160 is in the closed configuration shown in FIGS. 21A-21E. The transfer member 2160 is configured to remain in its closed configuration until a distally directed force of a predetermined magnitude (e.g., about 6 lbf to about 10 lbf) is applied to the transfer member 2160. In some embodiments, when the distally directed force of the predetermined magnitude is applied to the transfer member 2160, the distal shoulder 2154 can push past the detent 2162, thereby prying the transfer member 2160 open and converting it to the open configuration. With the transfer member 2160 in its open configuration, the distal exit tube 2150 and the associated piercing member 2140 are free to move distally relative to the transfer member 2160.

[0078] As discussed above with reference to the transfer configuration shown in FIG. 17 , the amount of force required to drive the geometric feature 844 through the distal stop member 814 can be from about 3 lbf to about 5 lbf. After the dual-chamber injection system 800 is in the transfer configuration, additional force forces fluid from the proximal chamber 822 to the distal chamber 824 (see FIG. 17 ). After the majority of the fluid has been transferred from the proximal chamber 822 to the distal chamber 824, the dual-chamber injection system 800 is in the mixing configuration. Upon further application of distally directed force, as shown in FIGS. 19 and 20 , the additional distally directed force applied to the plunger member 816 moves the distal stop member 814 distally relative to the transfer member 860 until the radially extending members / wings 868 abut the inner surface of the guide / funnel 813 of the distal stop member 814. At this point, due to interference between the member / wing 868 and the guide / funnel 813, a greater force (e.g., about 6 lbf to about 10 lbf) can be applied to the distal shoulder 854, 2154 formed by the proximal end of the distal outlet tube 850, 2150, thereby wedging the transfer member 860, 2160 into its respective open configuration. Thus, the fluid transfer assembly 830, 2130 shown in FIGS. 8-21E can easily penetrate the distal stopper member 814 and convert the dual chamber infusion system 800 from the delivery configuration shown in FIG. 16 to the transfer configuration shown in FIG. 17 with the application of a smaller force (e.g., about 3 lbf to about 5 lbf). The fluid transfer assembly 830 can also easily transfer fluid from the proximal drug chamber 822 to the distal drug chamber 824 while the dual chamber infusion system 800 is in the transfer configuration shown in FIG. 17. The fluid transfer assembly 830 can be easily opened by applying a greater force (e.g., about 6 lbf to about 10 lbf) to transform the transfer member 860 from its closed configuration to its open configuration, thereby providing a wedge-like push to open the transfer member 860.

[0079] Thus, the fluid transfer assembly 830 facilitates improved control during transfer of fluid from the proximal drug chamber 822 to the distal drug chamber 824, mixing of the fluid with the second drug component in the distal drug chamber 824, and ejection of the mixed multi-component infusate from the dual-chamber injection system 800. The fluid transfer assemblies 830, 2130 shown in Figures 8-21E and described above can be used with off-the-shelf components such as stopper members, syringe bodies, cartridge bodies, and Luer connectors. Fluid transfer can also be used with safety needle retraction members such as plunger members and needle hubs.

[0080] Although specific amounts of force are described, modifications can be made to fluid transfer assembly 830 to vary the amount of force required to penetrate distal stop member 814, to transfer fluid from proximal drug chamber 822 to distal drug chamber 824, and to expel the mixed multi-component infusate. Varying the amount of force required to achieve various functions of dual chamber injection system 800 provides improved control of system 800.

[0081] Exemplary fluid transfer assembly for a dual chamber safety injection system having a polymeric transfer member 22 illustrates a fluid transfer assembly 2230 and a distal stopper member 814 for use in a dual-chamber injection system according to some embodiments. Other components of the dual-chamber injection system may be the same as those in the dual-chamber injection system 800 illustrated in FIG. 8 and described above. These other components may be off-the-shelf components, such as a stopper member, syringe body, cartridge body, and luer connector. Other components may also be safety needle retraction components, such as a plunger member and needle hub.

[0082] The fluid transfer assembly 2230 shown in Figure 22 includes a piercing member 840 and a distal exit tube 850. Both of these components are identical to those shown in Figures 8-21E and described above. The difference between the fluid transfer assembly 2230 and the fluid transfer assembly 830 described above is the transfer member 2260. Unlike the transfer member 860 described above, which is formed from a sheet of metal, the transfer member 2260 is formed from a polymer. In some embodiments, the transfer member 2260 is molded from a polymer.

[0083] The fluid transfer assembly 2230, distal stop member 814 and guide / funnel 813 are in the delivery configuration of Figure 22. In that configuration, geometric feature 844 is located at the center of each of guide / funnel 813 and distal stop member 814.

[0084] 23 illustrates a fluid transfer assembly 2230 and distal stop member 814 in a transfer configuration, according to some embodiments. As described above with respect to the fluid transfer assembly 830, the fluid transfer assembly 2230 and distal stop member 814 are configured such that a predetermined amount of distally directed force (e.g., about 3 lbf to about 5 lbf) applied to the distal stop member 814 causes the geometric feature 844 to penetrate the distal stop member 814. In the transfer configuration, the piercing member 840 and the transfer member 2260 also penetrate the distal stop member 814. A recess in the longitudinal cross section of the transfer member 2260 forms a fluid passageway (e.g., trench) 2261 through the distal stop member 814. As described above, once the dual-chamber injection system is in the transfer configuration, continued application of a distally directed force forces fluid from the proximal chamber to the distal chamber (not shown).

[0085] FIG. 24 illustrates the fluid transfer assembly 2230 and distal stop member 814 after a dual-chamber injection system according to some embodiments has reached a mixing configuration. The transfer member 2260 includes a pair of latches 2262 that, when biased to a closed state, prevent the distal outlet tube 850 from moving proximally past the latches 2262 (see FIGS. 22 and 23). The latches 2262 are actuated when they abut a surface of the guide / funnel 813 and are actuated from the proximal end of the distal outlet tube 850. Actuation of the latches 2262 causes the latches 2260 to deform to an open state, as shown in FIG. 24, thereby allowing the distal outlet tube 850 to move proximally past the latches 2262. The latches 2262 are configured such that a force of about 6 lbf to about 10 lbf applied to the distal stop member 814 sufficient to actuate the latches 2262 is sufficient. The transfer member 2260 also includes a funnel 2263 to provide a smoother transition (ie, minimize fluctuations in force / resistance) as the proximal end of the distal outlet tube 850 passes through the transfer member 2260.

[0086] 25-27 show the proximal end of a fluid transfer assembly 2230 according to some embodiments. The transfer member 2260 and its latch 2262 are shown in FIGS. 25 and 26. The latch is configured to remain in its biased closed state when a force sufficient to penetrate the penetrating member 840 through the distal stopper member (e.g., about 3 lbf to about 5 lbf) is applied. This prevents premature release of the distal outlet tube 850 and penetrating member 840 from the transfer member 2260 until a force sufficient to actuate the latch 2262 (e.g., about 6 lbf to about 10 lbf) is applied. Thus, the latch 2262 of the fluid transfer assembly 2230 shown in FIGS. 22-27 provides a mechanism for controlling the distal stopper penetration, fluid transfer, and fluid ejection steps of multi-component infusate delivery as described above.

[0087] FIG. 28 illustrates a fluid transfer assembly 2830 for use in a dual-chamber injection system according to some embodiments. This fluid transfer assembly 2830 is similar to the fluid transfer assembly 2230 illustrated in FIGS. 22-27. The difference between the fluid transfer assemblies 2230, 2830 lies in the design of the latching mechanism of the transfer members 2260, 2860. In addition to the latch 2862, the transfer member 2860 illustrated in FIG. 28 also includes a pair of frangible links 2864 (see FIG. 29A). The frangible links 2864 prevent the latch 2862 from deforming to its open state until sufficient force (e.g., about 6 lbf to about 10 lbf) is applied to the distal stopper member. This additional mechanism provides additional control over the distal stopper penetration, fluid transfer, and fluid ejection steps of multi-component infusate delivery, as described above.

[0088] 29B-29D illustrate a transfer member 2960 for use with a fluid transfer assembly, according to some embodiments. The transfer member 2960 is very similar to the transfer member 2860 shown in FIG. 29A. For example, the transfer member 2960 shown in FIGS. 29B-29D also includes a pair of latches 2962 that form a latching mechanism. The difference between the transfer members 2860 and 2960 is that the transfer member 2960 shown in FIGS. 29B-29D includes only a single frangible link 2964. The frangible link 2964 prevents the latch 2962 from deforming to its open state until sufficient force (e.g., about 6 lbf to about 10 lbf) is applied to the distal stopper member. This single frangible link 2964 design provides another design option for improved control over the distal stopper penetration, fluid transfer, and fluid ejection steps in multi-component infusate delivery, as described above.

[0089] FIGS. 29E-29H illustrate a transfer member 2960' including a distal end, a proximal end, and a frangible link 2964'. The transfer member has an internal channel 2966 defined by the inner surface of the transfer member 2960' and extending therethrough to facilitate fluid flow. The transfer member 2960' can be configured with a single channel or multiple channels. The transfer member 2960' shown in FIGS. 29E-29H has four channels. The internal channels 2966 extend from the proximal end to the distal end of the transfer member 2960'. Alternatively, the internal channels 2966 may extend a portion of the length of the transfer member 2960'. The proximal end of the transfer member 2960' is configured to circumferentially surround the proximal end of the penetrating member (2968; see FIG. 29G) by forming a complete, unbroken ring. The circumferential nature of the proximal end of the transfer member 2960' increases the radial stiffness of the transfer member 2960' and resists the crushing forces generated when the proximal end of the transfer member 2960' penetrates the rubber material of the stopper member. The transfer member 2960' can be constructed of a polymer such as COC, COP, polypropylene, or other medical-grade polymers. Attachment of the transfer member 2960' to the penetrating member 2968 can be achieved by sliding the transfer member 2960' over the proximal end of the penetrating member 2968. The proximal end of the transfer member 2960' is configured to resiliently expand to allow the proximal end of the penetrating member 2968 to pass through the proximal end opening of the transfer member 2960'. After the proximal end of the penetrating member 2968 passes adjacent the proximal end of the transfer member 2960', the proximal end opening of the transfer member 2960' resiliently snaps back to a smaller diameter, preventing the transfer member 2960' from disengaging from the penetrating member 2968. Once fluid transfer is complete, the user applies a distally directed force to the plunger member, thereby overcoming / breaking the frangible link 2964' and allowing the penetrating member 2968 to move longitudinally relative to the transfer member 2960'.

[0090] Exemplary Dual Chamber Safety Injection System Conversion Kit FIG. 30 illustrates a fluid transfer assembly 3002 that can form part of a dual-chamber injection system conversion kit 3000 (see FIGS. 31-34). The fluid transfer assembly 3000 can be used with a pre-fabricated syringe, such as that shown in FIG. 31, to convert a single-chamber injection system to a dual-chamber injection system, as described below. The fluid transfer assembly 3002 includes a piercing member 840, a transfer member 2260, and a distal exit member 3050, which are similar to the corresponding components described above. A latch 3051 on the distal exit member 3050 allows the fluid transfer assembly 3002 to couple to the proximal end of a needle. A split distal end 3058 of the distal exit member 3050 allows the fluid transfer assembly 3002 to couple to various exit styles (e.g., needles, luer connectors, tubing).

[0091] 31-34 illustrate a method for converting a single-chamber injection system using a dual-chamber injection system conversion kit 3000. In the step shown in FIG. 31, a fluid transfer assembly 3002 is inserted through the proximal opening of a pre-fabricated syringe body 3010. The distal outlet tube 3050 of the fluid transfer assembly 3002 is threaded onto the proximal end of the needle 3072 of the needle hub assembly 3070, thereby coupling the fluid transfer assembly 3002 to the needle 3072 and the needle hub assembly 3070.

[0092] FIG. 32 shows the fluid transfer assembly 3002 coupled to the needle hub assembly 3070.

[0093] 33 illustrates the addition of the dried / lyophilized components 3015 of the multi-component injectate into the syringe body 3010 through the proximal opening. A pre-fabricated distal stopper member 3014 is then inserted through the proximal opening of the syringe body 3010 until the proximal end of the piercing member 840 (see FIG. 30) is centered within the distal stopper member 3014. Placement of the distal stopper member 3014 within the syringe body 3010 forms a distal drug chamber 3024 in which the dried / lyophilized components 3015 are disposed.

[0094] 34 illustrates the addition of the liquid / diluent component 3017 of the multi-component injectate into the syringe body 3010 through the proximal opening. A pre-fabricated proximal stopper member 3012 is then inserted through the proximal opening of the syringe body over the liquid / diluent component 3017. Placing the proximal stopper member 3012 within the syringe body 3010 forms a proximal drug chamber 3022 in which the liquid / diluent component 3017 is disposed. Next, a finger flange 3080 and plunger member 3016 are added to the current dual-chamber injection system. The needle hub assembly 3070 and plunger member 3016 can include safety needle retraction components such as a plunger member and a needle hub.

[0095] Although the fluid transfer assembly 3002 has been described as including a penetrating member 840, a transfer member 2260, and a distal exit member 3050 similar to the corresponding components described above, the fluid transfer assembly in the dual chamber safety injection system conversion kit may include various equivalent components, such as the transfer member 860 and / or the distal exit member 850 described above.

[0096] Exemplary Finger Flange with Anti-Backout Feature In a multi-chamber multi-component mixing injection system, pressure can build up in a first chamber when fluid from one of the other chambers is forced into the first chamber, which can push the plunger member backward / proximally, thereby interfering with the function of the multi-chamber multi-component mixing injection system.

[0097] 35-43 illustrate the addition of a one-way ratchet to the dual-chamber injection system described herein. The one-way ratchet allows the plunger member to move distally with minimal resistance and prevents proximal movement by engaging the ratchet teeth on the outer surface of the plunger member. During the mixing phase of a multi-component injection formulation, air pressure builds up in the distal chamber as the liquid is transferred. This pressure buildup creates a proximal reaction force on the thumb. The addition of a toothless ratchet counteracts this reaction force and prevents proximal movement of the plunger member. With the toothless ratchet engaged, the user does not need to continuously apply distal force to maintain the plunger member position. The ratchet can also be toothless if the outer surface of the plunger member is smooth and the ratchet arms are configured to bite into the plunger member. In this case, the position of the plunger member is maintained in infinitesimal increments. Alternatively, the ratchet may engage an annular groove or threads on the outer surface of the plunger member to provide incremental position stops. The annular groove may provide a tactile and / or audible click or feedback to the user that the ratchet is engaged.

[0098] 35 illustrates a dual-chamber injection system 3500 including a finger flange 3580 having an anti-backup feature 3590 according to some embodiments. The anti-backup feature 3590 prevents proximal movement of the plunger member 3516 relative to the syringe body 3510 while allowing distal movement. In addition to the syringe body 3510, plunger member 3516, finger flange 3580, and anti-backup feature 3590, the dual-chamber injection system 3500 also includes proximal and distal stop members 3512, 3514 and a needle hub assembly 3570. The plunger member 3516 is inserted into the interior 3518 of the syringe body 3510 through a proximal opening in the syringe body. The proximal and distal stop members 3512, 3514, together with the syringe body 3510, define a proximal drug chamber 3522. The distal stopper member 3514 and the syringe body 3510 define a distal drug chamber 3524. The plunger member 3516 can be manually manipulated to insert the proximal stopper member 3512 relative to the syringe body 3510. When an incompressible fluid is disposed in the proximal drug chamber 3522, inserting the proximal stopper member 3512 also inserts the distal stopper member 3514 relative to the syringe body 3510.

[0099] 36-39 illustrate a finger flange 3580 configured to attach to a minor flange 3511 formed on the proximal end of a syringe body 3510 (see FIG. 39). As shown in FIG. 36, the finger flange 3580 defines a first recess 3582 configured to receive the minor flange 3511 to couple the finger flange 3580 to the syringe body 3510. The finger flange 3580 also defines a second recess 3584 configured to receive an anti-backup mechanism 3590. The anti-backup mechanism 3590 includes a pair of brake tabs 3592 configured to provide a counterforce against proximal movement of the plunger member 3516 relative to the anti-backup mechanism 3590 while allowing distal movement. The opposing forces can include a frictional force when the brake tabs 3592 contact the outer surface 3517 of the plunger member 3516 and a reaction force when the brake tabs 3592 bite into the outer surface 3517 of the plunger member 3516. The acute angles of the brake tabs 3592 create a reaction force parallel to the plunger member 3516 exerted by the sharp curved edge of each of the brake tabs 3592 contacting the surface 3517 of the plunger member 3516. This reaction force, along with the frictional force, prevents the plunger member 3516 from moving in the proximal direction. The finger flange 3580 further defines a "C" shaped opening 3586 configured to receive the plunger member 3516 (see FIG. 35). The "C" shaped opening 3586 allows the finger flange 3580 to slide onto the minor flange 3511 from the side of the minor flange 3511 after the plunger member 3516 is inserted during assembly. Additionally, the "C" shaped finger flange 3580 and anti-backup feature 3590 shown in FIGS. 35-39 can slide / snap onto the minor flange 3511 of the syringe body 3510 after the plunger member 3516 is inserted. The syringe body 3510 with the plunger member 3516 threaded onto the proximal stopper member 3514 can be packed more securely into shipping trays for transport. The finger flange 3580 with the anti-backup feature 3590 is fastened after shipping and snapped around both the syringe body 3510 and plunger member 3516.

[0100] As shown in FIG. 37 , the anti-backup mechanism 3590 is a generally “C” shaped clip. In some embodiments, the anti-backup mechanism 3590 is cut or stamped from a metal sheet, after which certain portions thereof are bent into their final shape. The anti-backup mechanism 3590 includes a pair of brake tabs 3592 configured to provide a frictional force opposing proximal movement of the plunger member 3516, as described above. The brake tabs 3592 are resiliently deformable and self-actuating. The brake tabs 3592 extend distally at an acute angle relative to the plane of the anti-backup mechanism 3590 (i.e., the brake tabs 3592 are bent downward). The angle and resilience of the brake tabs 3592 allow the plunger member 3516 to slide distally past the brake tabs 3592. As the plunger member 3516 is pulled proximally relative to the brake tab 3592, the brake tab 3592 contacts and bites into the outer surface 3517 of the plunger member 3516, preventing proximal movement of the plunger member 3516 relative to the brake tab 3592. Because the brake tab 3592 is self-actuating, upon attempted proximal movement, the brake tab 3592 engages the plunger member 3516 by increasing the frictional force and bite into the plunger member 3516, preventing proximal movement thereof. In effect, the brake tab 3592 forms a pair of pawls that engage the plunger member 3516 and prevent proximal movement thereof. In some embodiments, the plunger member (not shown) is provided with and / or formed with annular groove threads thereon to enhance the ratcheting effect of the brake tab 3592. The anti-backup mechanism 3590 and brake tab 3592 prevent the plunger member 3516 from being removed from the dual chamber injection system 3500 after use.

[0101] The anti-backout mechanism 3590 also includes a pair of retention tabs 3594 configured to retain the anti-backout mechanism 3590 in the second recess 3584 of the finger flange 3580. The retention tabs 3594 are configured to bend inwardly, thereby gripping the inside of the second recess 3584 of the finger flange 3580 with a frictional and reactive force to prevent removal of the anti-backout mechanism 3590 from the second recess 3584. The retention tabs 3594 are also self-actuating, providing increasing frictional and reactive forces as the anti-backout mechanism 3590 is pulled from the second recess 3584. In the embodiment shown in FIG. 38 , the finger flange 3580 includes a pair of openings 3588 configured to receive the retention tabs 3594 from the anti-backout mechanism 3590, retaining the anti-backout mechanism 3590 in the second recess 3584 by interference instead of friction.

[0102] 37 , the anti-backout feature 3590 includes four fit tabs 3596 configured to reduce the tolerance between the second recess 3584 and the anti-backout feature 3590, allowing for a tighter fit of the anti-backout feature 3590 within the second recess 3584. In some embodiments, the finger flange 3580 is molded from a polymer, thereby limiting the minimum size of the recess that can be accurately and precisely formed therein, resulting in a larger original tolerance. Meanwhile, the anti-backout feature 3590 is cut from sheet metal, thereby having a thinner profile than the height of the second recess 3584. The fit tabs 3596 increase the thickness / height of the anti-backout feature 3590, thereby providing a tighter fit within the second recess 3584. The fit tabs 3596 also provide rigidity to the anti-backout feature 3590. Thus, when the plunger member 3516 is pulled proximally, the brake tab 3592 (due to its resilience and angle) exerts an outward force on the anti-backup feature 3590. This outward force is transmitted through the anti-backup feature 3590 and fit tab 3596 and, due to the rigidity of the anti-backup feature 3590, presses against the inside of the second recess 3584 of the finger flange 3500. This outward force is a counter force to the frictional force and a reaction force applied to the plunger member 3516, preventing its proximal movement.

[0103] FIGS. 40-43 illustrate a dual-chamber injection system 4000 with a finger flange 4080 having an anti-backout feature 4090, according to some embodiments. The dual-chamber injection system 4000 has many of the same components as the dual-chamber injection system 3500 described above and illustrated in FIGS. 35-39. These components have the same numbers as the corresponding components in the dual-chamber injection system 3500. The difference between the dual-chamber injection systems 3500, 4000 lies in the finger flanges 3590, 4090. Unlike the finger flange 3590 illustrated in FIGS. 36 and 37, which has a "C"-shaped opening 3586 for receiving the plunger member 3516, the finger flange 4090 illustrated in FIGS. 41 and 4 has an "O"-shaped opening 4086 for receiving the plunger member 3516. The "O"-shaped opening 4086 provides an additional mechanism for preventing removal of the plunger member 3516 from the dual-chamber injection system 4000 after use.

[0104] As shown in FIG. 42 , the anti-backup feature 4090 in the finger flange 4080 has an “O” and / or rectangular shape. The anti-backup feature 4090 can be cut from a metal sheet. The “O” and / or rectangular shape of the anti-backup feature 4090 allows the anti-backup feature 4090 to be inserted into the finger flange 4080, and the finger flange 4080 with the anti-backup feature 4090 to snap onto the minor flange 3511 before the plunger member 3516 is inserted into the syringe body 3510 (see FIGS. 40 and 43 ). In such an embodiment, the plunger member 3516 is inserted through the “O” shaped opening 4086 in the finger flange 4080. Thus, interference between the “O” shaped opening 4086 in the finger flange 4080, the plunger member 3516, and the syringe body 3510 prevents the finger flange 4080 from being removed from the syringe body 3510 after assembly. 35-40, which has a "C" shaped opening 3586, can slide / snap onto the minor flange 3511 from the side of the minor flange 3511 at any time during assembly. Additionally, the "O" shaped opening 4086 in the finger flange 4080 aligns the plunger member 3516 within the syringe body 3510.

[0105] The brake tab 4092 of the anti-backup mechanism 4090 shown in FIG. 42 is the same as the brake tab 3592 of the anti-backup mechanism 3590 shown in FIG. 37 described above. The retention tab 4094 of the anti-backup mechanism 4090 shown in FIG. 42 is similar to the retention tab 3594 of the anti-backup mechanism 3590 shown in FIG. 37 described above. The difference is that the anti-backup mechanism 4090 has a single retention tab 4094, while the anti-backup mechanism 3590 has a pair of retention tabs 3594. The fit tab 4094 of the anti-backup mechanism 4090 shown in FIG. 42 is similar to the fit tab 3596 of the anti-backup mechanism 3590 shown in FIG. 37 described above. The difference is that the anti-backup mechanism 4090 has three fit tabs 4094, while the anti-backup mechanism 3590 has four fit tabs 3594.

[0106] The anti-backup mechanism 4090 depicted in Figures 40-43 is symmetrical, simplifying mass assembly, both manual and automated. In embodiments where the plunger member (not shown) has an annular groove and / or threads, the anti-backup mechanism 4090 can prevent removal of the plunger member 3516 from the dual chamber injection system 4000. Additionally, the pair of long beams of the "O" shaped anti-backup mechanism 4090 are deformable, allowing the anti-backup mechanism 4092 to bend outward, thereby transmitting an outward reaction force to the inner wall of the second recess 4084 via the outer / long fit tabs 4096.

[0107] Exemplary Resilient Needle Latch 44A-45B show a needle latch mechanism 4490 for use in a safety injection needle retraction system 4400, according to some embodiments. The resilient needle latch 4490 is disposed on the needle hub 4474 to hold the needle 4472 at the distal end of the syringe body 4410 during injection and to release the needle 4472 for retraction after the injection is completed. FIG. 44A is a half-sectional view of the injection system 4400 showing the needle 4472 in a latched state, with the needle latch 4490 coupling the needle 4472 to the needle hub 4474. The needle 4472 has an annular latch groove 4476 that couples to the resilient needle latch 4490. The resilient needle latch 4490 is configured to have a latched state (see FIG. 44A ) in which the pair of latch arms 4492 are constrained and / or compressed into engagement with the annular latch groove 4476 of the needle, and an unlatched state (see FIG. 44B ) in which the latch arms 4492 are readily free to open and disengage from the annular latch groove 4476, releasing the needle 4472 for retraction. The needle hub 4474 defines a recess 4478 having an inner diameter and a restraining surface configured to restrain the resilient needle latch 4490 in the latched configuration.

[0108] 44B is another half-sectional view illustrating the needle unlatching process. To unlatch the needle 4472, the needle 4472 and associated resilient needle latch 4490 are pushed distally by advancing a plunger member (not shown). The resilient needle latch 4490 is configured so that the needle latch 4490 is pushed distally after an injection is substantially complete. Distal movement of the resilient needle latch 4490 moves it out of the recess 4478, allowing the latch arm 4492 to slide distally over a restraining surface within the recess 4478, thereby allowing the latch arm 4492 to expand radially (because the latch arm 4492 is biased to expand). The radial expansion of the latch arm 4492 disengages the latching surface of the latch arm 4492 from the annular latch groove 4476 of the needle, thereby releasing the needle 4472 to be retracted proximally relative to the needle hub 4474 and syringe body 4410. The needle retraction mechanism can be used in conjunction with a resilient needle latch 4490.

[0109] FIGS. 44C and 44D are half-sectional views (rotated 90 degrees on the longitudinal axis from FIGS. 44A and 44B) showing the flexible unlatching force arm / retention tab 4494 pair of the resilient needle latch 4490. FIG. 44C shows the needle 4472 in a latched state, and FIG. 44D shows the needle 4472 in an unlatched state. A desired force to unlatch the needle 4472 is about 2 lbf to about 4 lbf. To configure the resilient needle latch to unlatch at the desired unlatch force, the retention tab 4494 engages a generally proximally facing annular shelf 4471 inside the nosecone of the needle hub 4474. In FIG. 44C, the retention tab 4494 is in a straightened state, preventing the resilient needle latch 4490 from moving distally out of the recess (see FIG. 44A). The retention tab 4494 is configured such that when a distally directed force is applied to the needle assembly (thereby transmitting the distally directed force to the resilient needle latch 4490), the retention tab 4494 engages the annular shelf 4471. The retention tab 4494 reacts to the distally directed needle unlatch force until a desired unlatch force is reached, at which point the retention tab 4494 bends proximally and deforms to a bent state, allowing the resilient needle latch 4490 to advance distally from the recess 4478, thereby removing the latch constraint and allowing the needle 4472 to be released. Figures 44E and 44F are perspective views of the resilient needle latch 4490 of Figures 44A-44D with the latch arm 4492 in an unlatched state and the retention tab 4494 in a straight state.

[0110] Exemplary Elastomeric Needle Retention System 45A-45D are half-sectional views illustrating a mechanism for retaining a needle 4572 during an injection and retracting the needle 4572 after an injection is completed, according to some embodiments. The safety injection system 4500 includes a needle 4572 (FIG. 45B) having a needle hub 4574, an elastomeric seal 4590, and an annular seal seat 4576. The elastomeric seal 4590 (FIG. 45C) has an inner sealing surface, a syringe sealing surface, and a needle hub sealing surface. The elastomeric seal 4590 is configured to provide a pressure seal between the interior of the syringe body 4510, the needle hub 4574, and the exterior of the needle 4572. The elastomeric seal 4590 is also coupled to the exterior of the needle 4572 by friction and / or mechanical engagement mechanisms, which provide resistance to proximal movement of the needle 4572 into the syringe body 4510 during an injection. The resistance to proximal movement is adjusted to be sufficient to allow an injection, but not so strong that it prevents the needle retraction mechanism from retaining and retracting the needle 4572 within the syringe body 4510 and / or plunger member. A proximal movement resistance greater than about 1.5 lbf and less than about 3.0 lbf provides sufficient resistance to movement to allow assembly and injection, while allowing the retraction spring to overcome the needle retention force and retract the needle 4572 (see FIG. 45D). Alternatively, the elastomeric seal may be an O-ring or a slab of elastomer (not shown) that is penetrated by the needle 4572 during assembly. In some embodiments, the needle 4572 has a distally facing surface that engages with an internal proximally facing surface of the needle hub 4574 to prevent distal movement of the needle 4572 during cap removal, handling, medication injection, and / or removal of the needle 4572 from the patient.

[0111] Exemplary Needle Hub Attachment Mechanism for a Polymer Syringe Body 46A-46E illustrate an attachment mechanism for coupling a needle hub 4674 to a polymeric syringe body 4610, according to various embodiments. In various embodiments, the polymeric syringe body 4610 is molded from a cyclic olefin copolymer or a cyclic olefin polymer. The polymeric syringe body 4610 has a needle retaining ledge 4611. As shown in FIGS. 46C-46E, the needle hub 4674 has a latch 4675 configured to fit into a space 4617 (see FIG. 46E) proximal to the needle retaining ledge 4611 after passing the needle hub 4611 distally, thereby coupling the needle hub 4674 to the polymeric syringe body 4610. The injection system also includes a gasket 4615 (see FIG. 46B) within the needle hub 4674 distal to the polymeric syringe body 4610.

[0112] 47A-47H illustrate attachment mechanisms for coupling a needle hub 4774 to a polymeric syringe body 4710, according to various embodiments. FIG. 47A is an exploded perspective view of a needle hub assembly including a needle 4772, a needle hub 4774, a needle retaining ring 4790, and a gasket 4715. While the embodiment shown in FIG. 47A includes a needle latch and a needle latch actuator, these components are optional in needle hub assemblies for use with molded polymeric injection system bodies; other needle hub assembly embodiments may omit the needle latch and needle latch actuator. In various embodiments, the polymeric syringe body 4710 is molded from a cyclic olefin copolymer or cyclic olefin polymer. As shown in FIG. 47D, the polymeric syringe body 4710 has a smooth needle coupling member 4711 at its distal end. The needle hub 4774 has a retaining ring 4774 for coupling over the needle coupling member 4711.

[0113] The metal retaining ring 4775 includes teeth 4777 (see FIGS. 47G and 47H) that are biased to bend more easily in one direction than the other, allowing the retaining ring 4775 to slide more easily proximally over the needle coupling member 4711 (see FIG. 47E) at the distal end of the molded polymeric syringe body 4710, while offering relatively greater resistance when removing the retaining ring 4775 distally over the needle coupling member 4711. In fact, the teeth 4777 of the retaining ring 4775 may even gouge / dig into the needle coupling member 4711 as the needle hub 4774 is pulled away from the polymeric syringe body 4710.

[0114] An automatic braking action occurs between the teeth 4777 and the polymeric syringe body 4710, which helps resist removal of the retaining ring 4775 on the needle binding member 4711. The teeth 4777 tend to bond more tightly to the needle binding member 4711 as more removal force is applied. This is due to the shallow angle formed between the teeth 4777 and the needle binding member 4711 after assembly, which increases friction between the teeth 4777 and the needle binding member 4711 as the removal force increases, preventing the teeth 4777 from disengaging from the needle binding member 4711. The dome-like curvature of the teeth 4777 and the surrounding metal of the retaining ring 4775 provide structural strength to the teeth 4777, which compress the needle binding member 4711 with a generally radial force, helping to enhance the automatic braking action and helping the teeth 4777 resist release of the needle binding member 4711. The interference between the needle coupling member 4711 and the retaining ring 4775 allows the needle hub 4772 to be attached to the polymeric syringe body 4710 in the proximal direction, while preventing the needle hub 4772 from being removed from the polymeric syringe body 4710 in the distal direction. The metal retaining ring 4775 has a higher hardness and elasticity than the polymeric syringe body 4710 due to its metallic composition.

[0115] Although the various components shown in Figures 31-34 are described as off-the-shelf or safety needle retraction components, the dual chamber injection system conversion kit 3000 and fluid transfer assembly 3002 can be used with a variety of injection systems and system components.

[0116] Exemplary Fluid Transfer Assembly for a Dual Chamber Safety Injection System 48-63 illustrate a dual-chamber injection system 5100 including a fluid transfer assembly configured to provide precise control of the handling, mixing, and delivery of components of a multi-component injectate, according to some embodiments. Similar to the dual-chamber injection system 100 shown in FIGS. 6A-7B, 7G-7P, and 8-29D, the dual-chamber injection system 5100 includes a syringe body 5110, proximal and distal stopper members 5114, 5112, and a plunger member 5116, as shown in FIG. 51. The plunger member 5116 is inserted into an interior 5118 of the syringe body 5110 through a proximal opening in the syringe body 5110. The syringe body 5110 also includes a capped distal needle interface 5120 at its distal end. While the dual-chamber injection system 100 shown in FIGS. 6A-7B and 7G-7P has a staked needle, the syringe body 5110 has a luer lock-type distal needle interface 5120. Note that the distal needle interface 5120 is not limited to a luer lock and may be other types of needle / tubing interfaces. The distal needle interface 5120 is capped to minimize contamination and facilitate the maintenance of an optional vacuum in the interior 5118 of the syringe body 5110. Benefits of the optional vacuum include reduced exposure of the drug to air, aiding in the transfer of liquid drug components from the proximal drug chamber 5122 to the distal drug chamber 5124, and eliminating the need to vent the distal drug chamber during drug mixing, which makes the capped distal needle interface 5120 possible. The capped distal needle interface 5120 minimizes user exposure in embodiments with toxic drug components.

[0117] The proximal and distal stopper members 5114, 5112, together with the syringe body 5110, define a proximal drug chamber 5122. The distal stopper member 5112 and the syringe body 5110 define a distal drug chamber 5124. The plunger member 5116 can be manually manipulated to insert the proximal stopper member 5114 relative to the syringe body 5110. When an incompressible fluid is disposed in the proximal drug chamber 5122, inserting the proximal stopper member 5114 also inserts the distal stopper member 5112 relative to the syringe body 5110.

[0118] While the dual-chamber injection system 100 shown in Figures 6A-7B and 7G-7P includes a needle with various openings for fluid transfer and delivery (see Figures 7C-7F), the dual-chamber injection system 5100 includes a fluid transfer assembly 5130 for fluid transfer and delivery.

[0119] 53 , a fluid transfer assembly 5130 according to some embodiments includes a spine assembly 5000 and a through tube 4800. The spine assembly 5000 includes a distal tube 5010 and a solid elongate member 5020 disposed partially within the distal tube 5010 and partially within the through tube 4800. The distal tube 5010 is typically a tubular member that is sealed by a hermetic weld between the solid elongate member 5020 and the distal tube 5010.

[0120] As described above, the solid elongate member 5020 may be coupled to the distal tube 5010 by welding. As shown in FIG. 55 , the proximal end of the distal tube 5010 forms a proximally facing shoulder 5012 at the junction with the solid elongate member 5020. The solid elongate member 5020 can be formed from a variety of wires and bands. Alternatively, the solid elongate member 5020 may be formed from a single piece of material. In either case, the solid elongate member 5020 defines a recessed region near its proximal end and a distally facing shoulder 5022.

[0121] 48 and 55, the through tube 4800 includes a tubular member 4810 movably coupled to a disk member 4830. The tubular member 4810 defines a pair of vacuum stoppers 4814 extending radially outwardly distally from an outer surface of the tubular member 4810. The vacuum stoppers 4814 are configured to interfere with a funnel surface 4910 of a funnel insert 4900 (see FIG. 49) to stabilize the relative positions of the through tube 4800 and the funnel insert 4900 in the delivery configuration and to adjust the amount of force required to move the funnel insert 4900 distally beyond the through tube 4800. The tubular member 4810 also defines a pair of intermediate openings 4816 into the interior of the tubular member 4810 adjacent each one of the pair of vacuum stoppers 4814. The tubular member 4810 further defines a pair of anti-backout tabs 4818 extending proximally radially inward from the outer surface of the tubular member 4810. The anti-backout tabs 4818 are configured to interfere with distally facing shoulders 5022 on the solid elongate member 5020 to limit distal movement of the solid elongate member 5020 relative to the through tube 4800. The tubular member 4810 also defines a pair of distal openings 4820 into the interior of the tubular member 4810 adjacent each one of the pair of anti-backout tabs 4818. The through tube 4800 can be formed by bending a single piece of sheet metal.

[0122] 48 and 55 , the disc member 4830 defines a plurality of radially inwardly extending stops 4832. The radially inwardly extending stops 4832 are movably connected to the tubular member 4810 and disposed adjacent the disc member 4830. One of the radially inwardly extending stops 4832 includes a connecting member 4836 connecting the disc member 4830 to the tubular member 4810. The radially inwardly extending stop 4832 defines an adjustable opening 4834 approximately in the center of the disc member 4830.

[0123] The adjustable opening 4834 is adjustable between a small configuration (shown in FIG. 48 ) and a large configuration (shown in FIG. 62 and described herein). When the adjustable opening 4834 is in the small configuration, a proximally facing shoulder 5012 on the distal tube 5010 interferes with a radially inwardly extending stop 4832 to prevent proximal movement of the distal outlet tube 5010 relative to the disc member 4830 of the through tube 4800. When the adjustable opening 4834 is in the large configuration, the distal tube 5010 is free to move proximally relative to the through tube 4800, as described. When the tubular member 4810 is forced distally relative to the disc member 4830 (e.g., by a vacuum in the distal drug chamber 5124 and / or a distally directed force applied to the plunger member 5116 driving the distal stopper member 5112 distally onto the through tube 4800), the radially inwardly expanding stopper 4832 is prevented from opening. However, when the tubular member 4810 is no longer forced distally relative to the disc member 4830, the radially inwardly expanding stopper 4832 is free to deform, changing the adjustable opening 4834 from a small to a large configuration (see FIG. 62 described herein).

[0124] Figures 48-50 show the penetration tube 4800, funnel insert 4900, and spine assembly 5000 as separate components. Figures 51-53 show the dual chamber injection system 5100 in a delivery configuration in which the vacuum stopper 4814 interferes with the funnel surface 4910 of the funnel insert 4900 of the distal stopper member 5112, increasing the amount of distally directed force required to initiate distal movement of the distal stopper member 5112 relative to the syringe body 5110. The increased amount of distally directed force required by the vacuum stopper 4814 and funnel surface 4910 promotes stability of the device with a vacuum in the distal drug chamber 5124, which is present in some embodiments.

[0125] 54 shows the assembly of the dual chamber injection system 5100. First, the spine assembly 5000 is inserted into the interior 5118 of the syringe body 5110. Next, the through tube 4800 is threaded onto the proximal end of the spine assembly 5000 to form the fluid transfer assembly 5130.

[0126] FIG. 55 shows the through tube 4800 after it has been snapped onto the spine assembly 5000. In this configuration, proximal movement of the spine assembly 5000 relative to the through tube 4800 is limited by interference between the proximally facing shoulder 5012 of the distal tube 5010 and the radially inward telescoping stop 4832 of the disk member 4830. Distal movement of the spine assembly 5000 relative to the through tube 4800 is also limited by interference between the distally facing shoulder 5022 of the solid elongate member 5020 and the anti-backout tab 4818 of the tubular member 4810. FIG. 55 shows the through tube 4800 on the spine assembly 5000. FIG. 55 also shows the sharp piercing tip 4812 penetrating the proximal opening 4822 defined by the piercing tip.

[0127] Figure 56 shows the next step in the assembly of the dual-chamber injection system 5100, following Figure 54. The funnel insert 4900 is inserted (e.g., screwed or pushed) into the distal stopper member 5112. The distal stopper member 5112 with the funnel insert 4900 is then inserted into the interior 5118 of the syringe body 5110 through the proximal opening until the vacuum stopper 4814 of the through tube 4800 interferes with the funnel surface 4910 of the funnel insert 4900 (see Figures 48 and 49), holding the distal stopper member 5112 in the delivery configuration of the dual-chamber injection system 5100 described herein. Next, the proximal stopper member 5114 is inserted into the interior 5118 of the syringe body 5110 through the proximal opening. Finally, the plunger member 5116 is coupled (e.g., screwed) to the proximal stopper member 5114.

[0128] In some embodiments, a liquid drug component can be introduced into the proximal drug chamber 5122 before the proximal stopper member 5114 is inserted into the syringe body 5110. In such embodiments, the incompressibility of the liquid drug component maintains the position of the proximal stopper member 5114 relative to the distal stopper member 5112 until an outlet flow path is opened to the proximal drug chamber 5122. In some embodiments, a liquid or dried / lyophilized drug component can be introduced into the distal drug chamber 5124 before or after the distal stopper member 5112 is inserted into the syringe body 5110. The liquid drug component in the distal drug chamber 5124 can be lyophilized in place using a vacuum and then maintained in the distal drug chamber using the capped distal needle interface 5120. If a dried / lyophilized drug component is introduced into the distal drug chamber 5124, a vacuum can be created in the distal drug chamber 5124 directly and the vacuum can be maintained using the capped distal needle interface 5120.

[0129] 57 shows the distal stopper member 5112, funnel insert 4900, through tube 4800, and spine assembly 5000 when the dual chamber infusion system 5100 is in the delivery configuration as described above. In some embodiments having a vacuum in the distal drug chamber 5124, the vacuum can generate a distally directed force of approximately 6.5 lbf on the distal stopper member 5112. Thus, the vacuum stopper 4814 of the through tube 4800 and the funnel surface 4910 of the funnel insert 4900 can be configured such that a distally directed force of more than 6.5 lbf is required to overcome interference between those components and cause the through tube 4800 to enter the funnel insert 4900 and penetrate the distal stopper member 5112. For example, the vacuum stopper 4814 of the penetration tube 4800 and the funnel surface 4910 of the funnel insert 4900 can be configured such that a distally directed force of 7.5 lbf is required to overcome interference between those components and cause the penetration tube 4800 to enter the funnel insert 4900 and penetrate the distal stopper member 5112. An additional 1 lbf of distally directed force can be provided by the user applying that force to the plunger member 5116.

[0130] Upon application of a distally directed force sufficient to overcome interference between the vacuum stopper 4814 of the penetration tube 4800 and the funnel surface 4910 of the funnel insert 4900, the sharp piercing tip 4812 of the penetration tube 4800 penetrates the distal stopper member 5112 until the proximal opening 4822 of the penetration tube 4800 is in fluid communication with the proximal drug chamber 5122, as shown in FIGS. 58 and 59. An exemplary force magnitude for driving the sharp piercing tip 4812 through the distal stopper member 5112 is about 4 lbf to about 5 lbf. Because the vacuum provides a distally directed force of about 6.5 lbf, the system can "auto-pierce" after overcoming the interference between the vacuum stopper 4814 of the penetration tube 4800 and the funnel surface 4910 of the funnel insert 4900. 58 and 59 show the dual-chamber infusion system 5100 in a transfer configuration with an outlet flow path open between the proximal and distal drug chambers (5122, 5124). The outlet flow path includes the proximal opening 4822 of the through-tube 4800, the interior of the through-tube 4800, and the distal opening 4820 of the through-tube. Because the proximal end of the solid elongate member 5020 of the spine assembly 5000 only occupies the distal-most end of the outlet flow path, there is very little resistance to fluid flow through the outlet flow path. In some embodiments, the force required to drive fluid flow is less than about 2.2 lbf. In embodiments in which a vacuum is present in the distal drug chamber 5124, a distally directed force (e.g., 6.5 lbf) generated by the vacuum can draw liquid drug components from the proximal drug chamber 5122, through the outlet flow path, and into the distal drug chamber 5124. As the liquid drug component is drawn from the proximal drug chamber 5122 , the proximal stopper member 5114 is also drawn distally relative to the syringe body 5110 .

[0131] FIG. 60 illustrates the next step in the method for injecting a multiple-component drug. The proximal drug chamber 5122, shown in FIG. 56, has been substantially or completely collapsed by either the action of a vacuum in the distal drug chamber 5124 and / or a distally directed force applied by a user to the plunger member 5116. The liquid drug component in the proximal drug chamber 5122 flows through the outlet channel into the distal drug chamber 5124. The lyophilized drug component in the distal drug chamber 5124 will be dissolved by the liquid drug component. The dual chamber injection system 5100 can be agitated to promote solubilization of the lyophilized drug component. At this point, the dual chamber injection system 5100 is in a mixing configuration. The various components of the dual chamber injection system 5100 can be configured to completely consume the vacuum by moving the liquid drug component into the distal drug chamber 5124.

[0132] In the mixing configuration shown in FIG. 60 , the mixed medication in the distal medication chamber 5124 is ready for injection. The syringe body 5100 includes a distal end opening 5030 (see FIG. 52 ) to allow fluid, such as the mixed medication, to exit the distal medication chamber 5124. As mentioned above, FIG. 52 illustrates one embodiment of the dual-chamber injection system 5100 including a capped distal needle interface 5120 that blocks the exit path from the distal medication chamber 5024 through the distal end opening 5030 until transfer of the liquid medication components and / or mixing of the mixed medication is complete. In such an embodiment, the capped distal needle interface 5120 is uncapped prior to injection. A needle assembly including an injection needle (not shown) can then be coupled to the uncapped distal needle interface 5120 prior to injection. In other embodiments, tubing can connect the uncapped distal needle interface 5120 to an IV bag prior to injection. After the uncapped distal needle interface 5120 is connected to the subject of injection, the injection can begin. Further application of a distally directed force to the plunger member 5116 causes both the proximal and distal stopper members 5114, 5112 to move distally relative to the syringe body 5110, forcing the mixed drug in the distal drug chamber 5124 out of the uncapped distal needle interface 5120 to perform the injection.

[0133] 61 and 62 show the proximal and distal stop members 5114, 5112 contacting each other after the dual chamber injection system 5100 is in the mixing configuration. FIG. 61 shows how forcing the tubular member 4810 against the disk member 4830 forces the radially inwardly telescoping stops 4832 together, holding the adjustable opening 4834 in its small configuration and thereby latching the spine assembly 5000 to the through tube 4800. The relatively thick (e.g., 0.009 inch) metal from which the through tube 4800 is made and the tight sliding clearance (e.g., 0.0025 inch) limits the extent to which the radially inwardly telescoping stops 4832 can subsequently telescope.

[0134] As shown in FIG. 62, further application of a distally directed force to the plunger member 5116 closes the gap between the disk member 4830 and the funnel insert 4900 ( FIG. 62). The distally directed force is then transmitted through the funnel insert 4900, pushing the disk member 4830 of the through tube 4800 distally away from the tubular member 4810 of the through tube 4800, while the tubular member 4810 is held stationary (e.g., by barbs (not shown)) within the distal stop member 5112 and funnel insert 4900. This causes the disk member 4830 to move distally from the tubular member 4810, bending the radially inwardly telescoping stopper 4832 away from the adjustable opening 4834 (see FIG. 48) and converting it from the small configuration to the large configuration. This unlatches the spine assembly 5000 from the through tube 4800, allowing the spine assembly 5000 to pass through the through tube 4800 and through the proximal stop member 5114. The through tube remains largely held to the proximal stop member 5112 and funnel insert 4900 by the disc member 4830.

[0135] FIG. 63 shows the dual chamber injection system 5100 after injecting the mixed medicament from the distal medicament chamber 5124. At this point, the dual chamber injection system 5100 is in its completed configuration. The proximal stop member 5114 contacts the distal stop member 5112, which in turn contacts the distal end of the syringe body 5110. The proximal end of the spine assembly 5000 penetrates both the distal and proximal stop members 5114, 5112 and enters the plunger member 5116. The penetration tube 4800 does not fully penetrate the proximal stop member 5112, thereby minimizing the risk of backflow into the plunger member 5116. In some embodiments, after injection of the mixed medicament, the spine assembly 5000 and its attached needle (not shown) can be retracted into the syringe body 5110 to provide a safe injection system.

[0136] The dual-chamber injection system 5100 and its components shown in FIGS. 48-63 prevent accidental and / or premature administration of a medication before the transfer of liquid medication components and / or mixing of the combined medication is complete. At the same time, the dual-chamber injection system 5100 includes low resistance to injection after the combined medication is prepared and ready for injection. The dual-chamber injection system 5100 achieves this by maintaining the spine assembly 5000 locked to the penetration tube 4800 during transfer and mixing of the liquid medication from the proximal medication chamber 5122 to the distal medication chamber 5124, thereby preventing incomplete mixing and fluid transfer. When the spine assembly 5000 is unlocked from the penetration tube 4800, there is minimal resistance to distal movement of the proximal and distal stop members 5114, 5114 on the spine assembly 5000. While a vacuum is described in the distal medication chamber of various embodiments, the vacuum is an optional feature of the injection system. Alternatively, a vacuum may be present in both the proximal and distal medication chambers in some embodiments. The dual chamber injection system 5100 is compatible with a needle retraction system, but can also be used without a needle retraction system. The dual chamber injection system 5100 is compatible with a wide variety of syringe sizes (e.g., 20cc syringes).

[0137] Although some of the prefilled dual chamber safety injection systems illustrated and described herein include luer lock connectors, the injection and dual chamber configurations including the anti-backup mechanism, safety injection needle retraction system and needle hub attachment mechanism described herein can be used with cartridges that are autoinjectors and injection systems with syringes having staked needles or luer slip connectors, as well as needleless syringes.

[0138] Various exemplary embodiments of the present invention are described herein. These examples are referred to in a non-limiting sense. They are provided to illustrate broader applicable aspects of the present invention. Various modifications may be made to the described invention, and equivalents may be substituted, without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process acts, or steps to the objective, spirit, or scope of the present invention. Moreover, as will be understood by those skilled in the art, each of the individual variations described and illustrated herein has individual components and features that can be readily separated from or combined with the features of any of the other embodiments without departing from the scope or spirit of the present invention. All such modifications are intended to be within the scope of the claims associated with this disclosure.

[0139] Any of the described devices for performing a subject diagnostic or interventional procedure may be provided in a packaged combination for use in performing such an intervention. These supply "kits" may further include instructions for use and may be packaged in a sterile tray or container as commonly employed for such purposes.

[0140] The present invention includes methods that may be performed with a subject device. The methods may include the act of providing such a suitable device. Such providing may be performed by an end user. That is, the act of "providing" merely requires the end user to obtain, access, approach, place, set up, activate, power on, or take other action to provide the required device in the subject method. Methods described herein may carry out the recited events in any order that is logically possible or in the sequence of events recited.

[0141] Exemplary embodiments of the present invention, including details regarding material selection and manufacturing, have been described above. Other details of the present invention may be understood in connection with the above-cited patents and publications, as well as generally known or understood by those skilled in the art. For example, those skilled in the art will understand that one or more lubricious coatings (e.g., hydrophilic polymers such as polyvinylpyrrolidone-based compositions, fluoropolymers such as tetrafluoroethylene, PTFE, hydrophilic gels, or silicones) may be used in connection with various portions of the device, such as relatively large interface surfaces of movably coupled portions, as needed, to facilitate, for example, low-friction manipulation or advancement of such objects relative to other portions of the instrument or nearby tissue structures. The same will be true for method-based embodiments of the present invention with respect to additional actions commonly or logically employed.

[0142] Furthermore, while the present invention has been described with reference to several examples optionally incorporating various features, it is not intended to be limited to what has been described or disclosed as contemplated with respect to each variation of the invention. Various modifications can be made to the described invention, and equivalents (whether described herein or not included for brevity) can be substituted without departing from the true spirit and scope of the invention. Furthermore, when a range of values ​​is provided, it is understood that all intervening values ​​between the upper and lower limits of that range, as well as other stated or intervening values ​​within the stated range, are encompassed within the scope of the invention.

[0143] It is also contemplated that any feature of the described inventive variations may be described and claimed independently or in combination with any one or more of the features described herein. Reference to a singular item includes the possibility of a plurality of the same items. More specifically, as used in this specification and the claims related thereto, the singular forms "a," "an," "said," and "the" include plural referents unless otherwise indicated. In other words, the use of articles allows for "at least one" of the subject items in the above description, as well as in the claims related to this disclosure. It should be noted that such claims may be drafted to exclude any element. Thus, this statement is intended to function as a preceding statement using exclusive terms such as "solely," "only," etc., in connection with the recitation of claim elements, or a preceding statement using a "negative" limitation.

[0144] Without using such exclusive language, the term "comprising" in any claim relating to this disclosure shall be construed as allowing for the inclusion of any additional elements, regardless of whether a given number of elements are recited in such claim or whether the addition of features would be considered to change the nature of the elements recited in such claim. Except as specifically defined herein, all technical and scientific terms used herein shall be given the broadest and most commonly understood meaning possible while maintaining the validity of the claims.

[0145] The breadth of the present invention is not limited to the examples and / or subject specification provided, but rather is limited only by the scope of the language of the claims associated with this disclosure.

Claims

1. 1. An injection system comprising: a molded body member having a retaining ledge at a distal end; a needle hub assembly coupled to a retaining ledge at the distal end of the molded body member, a needle hub coupled to the retaining ledge; a needle coupled to the needle hub; a pair of latches disposed at a proximal end of the needle hub; a continuous ring disposed proximally of the pair of latches; and a needle hub assembly having: the pair of latches are configured to interfere with the retention ledge to couple the needle hub to the retention ledge of the molded body member; The injection system, wherein the pair of latches extend distally from the continuous ring.

2. 10. The system of claim 1, The system further comprising a gasket disposed between the distal end of the molded body member and an inner surface of the needle hub.

3. 10. The system of claim 1, The system, wherein the body member is molded from a cyclic olefin copolymer or a cyclic olefin polymer.

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