Systems and methods for multiple site injections

Abstract

To provide a system and method related to a syringe for delivering microliter-range doses of fluid in a medical environment.SOLUTION: An injection system includes a syringe body having proximal and distal ends, a syringe interior, and a syringe flange at the proximal end thereof. The system also includes an injectable fluid disposed in the syringe interior. The system further includes a finger flange coupled to the syringe flange. Moreover, the system includes a stopper member disposed in the syringe interior. In addition, the system includes a plunger ratchet member coupled to the stopper member. The system also includes a plunger tube disposed coaxially around at least a part of the plunger ratchet member and operatively coupled thereto.SELECTED DRAWING: Figure 56

Description

[Technical Field]

[0001] The present invention relates generally to injection systems, devices and processes for facilitating various levels of control over fluid injection, and more particularly to syringe-related systems and methods for delivering doses of fluid in the microliter range in a medical environment. [Background technology]

[0002] Millions of syringes, such as those shown at 2 in FIG. 1A, 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. Indeed, in some countries, such as the United States, due to concerns about maintaining sterility and regulatory constraints, when 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.

[0003] 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 medication intravenously to a patient, with or without the use of an intravenous infusion bag. The luer fitting 14 of the syringe in FIG. 2A is sometimes referred to as a "male" luer fitting, and the luer fitting 18 of FIG. 2B is sometimes referred to as a "female" luer fitting, with one of the luer interfaces being threaded (in which case the configuration may be referred to as a "luer lock" configuration) to couple the two through relative rotation, sometimes in combination with a compressive load. In other words, in one luer lock embodiment, rotation, possibly along with compression, is used to engage the threads of the male fitting 14, which are configured to engage a flange on the female fitting 18 to create a fluid-tight coupling between the devices. In another embodiment, a tapered interface shape may be utilized to provide a luer engagement using compression without threads or rotation (such configurations are sometimes referred to as "slip-on" or "conical" luer configurations). While such luer connections are perceived as relatively safe for operators, they carry the risk of spillage, leakage, or component damage during loading to provide a luer connection. On the other hand, needle injection configurations carry the risk of a sharp needle contacting or puncturing a person or unwanted structures. For these reasons, so-called "safety syringes" have been developed.

[0004] 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 a self-retracting configuration may be associated with issues of blood splatter / aerosolization, safe storage of pre-loaded energy that may cause false activation and 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 rate control, which may be associated with pain and patient discomfort.

[0005] 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 include 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 35 and the distal end 37 of the stopper member 36. The stopper member 36 may comprise a standard butyl rubber material, 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 34 structure and material. The proximal end of the syringe body 34 in FIG. 5B includes 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 surround the entire circumference or a portion of the circumference of the syringe body 34. A partial flange is known as a “clipped flange,” and the other 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 stopper member 36 can be disposed within the syringe body 34 to form a contained volume within the medication chamber or reservoir 40 and aid in the evacuation of associated fluids through the needle. The syringe body 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) or can be configured to have other cross-sectional shapes, such as oval.

[0006] 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, that attempt to meet all or at least some 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.

[0007] Some medications are administered to a patient at multiple sites during a single procedure, and at the same time, needles may be left exposed after the procedure, increasing the likelihood of an inadvertent needle stick.

[0008] What is needed is an injection system that overcomes the shortcomings of currently available configurations. In particular, what is needed is an injection system that injects fluids into multiple sites on a single patient. What is further needed is a safe injection system that functions with such multi-site injection systems. It would also be desirable for such syringe assemblies to utilize the existing, relatively well-managed supply chain of conventionally available pre-filled cartridges and other off-the-shelf components, along with the corresponding assembly machinery and personnel. Summary of the Invention

[0009] Embodiments are directed to injection systems, particularly microliter range injection systems that include at least some off-the-shelf syringe components.

[0010] In one embodiment, an injection system includes a syringe body having a proximal end and a distal end, a syringe interior, and a syringe flange at the proximal end. The system also includes an injectable fluid disposed within the syringe. The system further includes a finger flange coupled to the syringe flange. The system further includes a stopper member disposed within the syringe. The system further includes a plunger ratchet member coupled to the stopper member. The system also includes a plunger tube coaxially disposed around and operably coupled to at least a portion of the plunger ratchet member.

[0011] In one or more embodiments, the system also includes a needle hub assembly distally coupled to the syringe body, the needle assembly including a non-retractable needle and a luer hub. The needle can be selected from the group consisting of a 30g needle, a 32g needle, a 34g needle, and a sub-34g needle.

[0012] In one or more embodiments, the plunger ratchet member includes a needle retaining feature disposed within the plunger, an energy storage member disposed within the plunger, and an energy storage member latch member disposed within the plunger. The system may also include a needle hub assembly coupled at a distal end to the syringe body. The needle assembly may include a needle having a needle proximal end feature, a hub, and a needle latch member configured to selectively prevent proximal movement of the needle relative to the hub. In response to manipulation of the plunger tube, the energy storage member latch member is converted from a latched state to an unlatched state, thereby allowing the needle to be at least partially retracted within the plunger. The needle may be configured to fully penetrate the stopper member and at least partially retract within the plunger. The energy storage member may be interconnected between an inner surface of the plunger ratchet member and the needle retaining feature. The plunger ratchet member may include a plurality of teeth disposed on an outer surface thereof. The distal end of the plunger tube may include a reduced diameter portion configured to interfere with each of the plurality of teeth to prevent proximal movement of the plunger tube relative to the plunger ratchet member. The latch member of the energy storage member may be configured to convert from a latched state to an unlatched state after the reduced diameter portion of the plunger tube moves distally past a proximal-most tooth of the plurality of teeth. The needle may be selected from the group consisting of a 30 g needle, a 32 g needle, a 34 g needle, and a sub-34 g needle.

[0013] In one or more embodiments, the system also includes a thumb pad coupled to a proximal end of the plunger tube. The plunger ratchet member can include a plurality of teeth disposed on an outer surface thereof. A distal end of the plunger tube can include a reduced diameter portion configured to interfere with each of the plurality of teeth to prevent proximal movement of the plunger tube relative to the plunger ratchet member.

[0014] In one or more embodiments, the system also includes a ratchet retaining member having a latch configured to interfere with a plurality of teeth on the plunger ratchet member to limit proximal movement of the plunger ratchet member relative to the ratchet retaining member. The ratchet retaining member can include a pair of resilient latches disposed on opposite sides thereof. The ratchet retaining member can be formed from a sheet of metal. The finger flange can define a space sized and shaped to retain the ratchet retaining member. The finger flange can also define a side opening leading to the space. The tooth pitch can be sized to provide a consistent injection dose per tooth. The plurality of teeth can comprise 10 teeth. The reduced diameter portion can include a plurality of leaves oriented toward the longitudinal axis of the plunger tube. The plurality of leaves can comprise four leaves.

[0015] In one or more embodiments, moving the plunger tube from its proximal position to its distal position expels a predetermined amount of fluid from within the syringe. The finger flange can include a distal stop surface configured to limit distal movement of the plunger tube beyond the distal position to prevent more than a predetermined amount of fluid from being expelled from within the syringe. The predetermined amount can be approximately 0.1 ml. The stopper member can be a pre-fabricated stopper member. The syringe body can be a pre-fabricated syringe body. The plunger ratchet member can define a drive recess at its proximal end.

[0016] In one or more embodiments, the finger flange includes a proximally extending tube coaxially disposed around a portion of the plunger tube and a return spring configured to bias the plunger tube from a distal position to a proximal position. The plunger tube can include a proximal flange configured to limit distal movement of the plunger tube relative to the proximally extending tube of the finger flange. The plunger tube can include a plurality of tabs oriented away from the longitudinal axis of the plunger tube. The proximally extending tube of the finger flange can define a plurality of corresponding windows configured to interfere with the plurality of tabs and limit proximal movement of the plunger tube relative to the proximally extending tube of the finger flange. The plunger tube can be coaxially disposed within the syringe body. The system can also include a priming screw configured to advance the plunger ratchet member to remove air from the interior of the syringe and expel a portion of the injectable fluid from the interior of the syringe.

[0017] In one or more embodiments, the finger flange includes a lever, the plunger ratchet member is operably coupled to the lever, and the plunger tube is operably coupled to the lever. The plunger tube can be coaxially disposed within the syringe body. The finger flange can also include a link connecting the plunger tube to the lever. The finger flange can also include a spring operably coupled to the lever. The lever can have a proximal position and a distal position. The spring can bias the lever toward the proximal position.

[0018] In one or more embodiments, the plunger tube has a proximal position corresponding to the proximal position of the lever and a distal position corresponding to the distal position of the lever. A spring can bias the plunger tube toward the proximal position. Moving the plunger tube from its proximal position to its distal position can move the lever from its proximal position to its distal position, causing the plunger ratchet member to move distally relative to the finger flange. The finger flange can include a distal stop surface configured to limit distal movement of the plunger tube beyond the distal position to prevent more than a certain amount of fluid from being expelled from within the syringe.

[0019] In one or more embodiments, moving the plunger tube a first distance from its proximal position to its distal position moves the plunger ratchet member a second distance distally relative to the finger flange, thereby expelling the injectable fluid from the syringe body. The ratio of the first distance to the second distance may be in the range of 1 to 5. The ratio of the first distance to the second distance may be approximately 2.5.

[0020] In one or more embodiments, application of a first force to the plunger tube results in application of a second force to the plunger ratchet member, with the ratio of the second force to the first force being the force ratio. The force ratio may be in the range of 1 to 5. The force ratio may be approximately 2.5. The force ratio can reduce the amount of force applied to the plunger tube to inject a viscous medication through the needle. The plunger tube and the plunger ratchet member can define a space at the proximal end of the plunger tube when the plunger tube is in its proximal position.

[0021] In one or more embodiments, the plunger ratchet member has a smooth outer surface, and the plunger tube includes a pair of inwardly biased members configured to permit distal movement of the plunger ratchet member relative to the plunger tube while preventing proximal movement of the plunger ratchet member relative to the plunger tube. The pair of inwardly biased members can be configured to deform a surface of the plunger ratchet member.

[0022] In another embodiment, a method for assembling an injection system includes attaching a finger flange to a pre-filled syringe. The pre-filled syringe includes a syringe body defining an interior of the syringe, an injectable fluid disposed within the syringe, and a stopper member disposed within the syringe and holding the injectable fluid within the syringe. The finger flange includes a plunger tube having a proximal opening. The method also includes inserting a plunger ratchet member into the plunger tube through the proximal opening. The method further includes connecting the plunger ratchet member to the stopper member within the syringe.

[0023] In one or more embodiments, the method further includes placing a thumb pad over the proximal opening of the plunger tube. The plunger ratchet member can include a plurality of teeth disposed on an outer surface thereof. The distal end of the plunger tube can include a reduced diameter portion configured to interfere with each of the plurality of teeth and prevent proximal movement of the plunger tube relative to the plunger ratchet member. The method can further include inserting the plunger ratchet member into the plunger tube through the proximal opening until a distal-most tooth of the plurality of teeth moves distally past the reduced diameter portion, limiting proximal movement of the plunger ratchet member relative to the plunger tube and finger flange.

[0024] In one or more embodiments, the finger flange includes a coaxially arranged proximally extending tube and a return spring configured to bias the plunger tube from a distal position to a proximal position. The method may further include inserting the plunger tube into the proximally extending tube to compress the return spring. The finger flange may include a lever and a link operably coupled to the lever. The method may further include inserting the plunger tube into the finger flange, thereby operably coupling the plunger tube to the lever via the link.

[0025] In yet another embodiment, an injection system includes a syringe body having a proximal end and a distal end, a syringe interior, and a syringe flange at the proximal end. The system also includes a finger flange coupled to the syringe flange, the finger flange including a plunger return spring. The system further includes a stopper member disposed within the syringe. The system further includes a plunger member coupled to the stopper member and operably coupled to the plunger spring. The plunger member has a proximal position and a distal position. The plunger spring biases the plunger member toward the proximal position.

[0026] In one or more embodiments, the stopper member and the syringe body define a distal chamber when the plunger member is in the proximal position. The plunger member can have a proximal chamber. The stopper member and the distal end of the plunger member can form a proximal one-way valve configured to fluidly couple the proximal and distal chambers when the plunger member is in the proximal position and to fluidly isolate the proximal chamber from the distal chamber when the plunger member is in the distal position. The system can also include a distal one-way valve configured to fluidly couple the distal chamber to an opening at the distal end of the syringe body when the plunger member is in the distal position and to fluidly isolate the distal chamber from the opening when the plunger member is in the proximal position. The stopper member can define a space. The distal end of the plunger member can be movably disposed within the space to movably couple the plunger member to the stopper member. The distal one-way valve can include a spherical member and a valve spring that biases the spherical member to a proximal position to close the distal one-way valve. Moving the plunger member from the distal position to the proximal position closes the distal one-way valve and opens the proximal one-way valve, allowing fluid in the proximal chamber to flow into the distal chamber.

[0027] In one or more embodiments, moving the plunger member from the proximal position to the distal position closes the proximal one-way valve and opens the distal one-way valve, allowing fluid in the distal chamber to flow out the distal opening of the syringe body. Moving the plunger member from the proximal position to the distal position can expel a volume of fluid from the distal chamber through the distal opening of the syringe body. The volume can be approximately 0.1 ml. The needle can be selected from the group consisting of a 30 g needle, a 32 g needle, a 34 g needle, and a sub-34 g needle. The system can also include a thumb pad coupled to the proximal end of the plunger member. The syringe body can be a pre-fabricated syringe body.

[0028] These and other embodiments of the present invention are described in the detailed description that follows. [Brief explanation of the drawings]

[0029] 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. [Figure 1] 1A and 1B show various aspects of conventional syringe configurations. [Figure 2] 2A and 2B show various aspects of conventional syringe configurations. [Figure 3] FIG. 3 shows various aspects of conventional syringe configurations. [Figure 4] 4A and 4B show various aspects of conventional syringe configurations. [Figure 5] 5A to 5C show various aspects of conventional syringe configurations. [Figure 6] FIG. 6 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 7] FIG. 7 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 8] FIG. 8 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 9] FIG. 9 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 10] FIG. 10 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 11] FIG. 11 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 12]FIG. 12 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 13] FIG. 13 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 14] FIG. 14 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 15] 15A-15C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 16] FIG. 16 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 17] FIG. 17 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 18] FIG. 18 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 19] FIG. 19 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 20] 20A-20C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 21] FIG. 21 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 22] FIG. 22 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 23] 23A-23C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 24] 24A-24C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 25] FIG. 25 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 26] FIG. 26 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 27] FIG. 27 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 28] FIG. 28 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 29] FIG. 29 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 30] FIG. 30 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 31] FIG. 31 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 32] FIG. 32 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 33] FIG. 33 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 34] FIG. 34 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 35] FIG. 35 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 36] FIG. 36 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 37] FIG. 37 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 38] FIG. 38 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 39] FIG. 39 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 40] FIG. 40 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 41] 41A and 41B illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 42] 42A and 42B illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 43] FIG. 43 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 44] FIG. 44 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 45] FIG. 45 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 46] FIG. 46 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 47] 47A-47C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 48] FIG. 48 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 49] FIG. 49 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 50]FIG. 50 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 51] FIG. 51 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 52] 52A-52C illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 53] FIG. 53 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 54] FIG. 54 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 55] FIG. 55 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 56] FIG. 56 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 57] FIG. 57 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 58] FIG. 58 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 59] 59A and 59B illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 60] FIG. 60 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 61] FIG. 61 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 62] 62A and 62B illustrate various aspects of a multi-site injection system and method according to some embodiments. [Figure 63] FIG. 63 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 64] FIG. 64 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 65] FIG. 65 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 66] FIG. 66 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 67] FIG. 67 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 68] FIG. 68 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 69] FIG. 69 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 70] FIG. 70 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 71] FIG. 71 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 72] FIG. 72 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 73] FIG. 73 illustrates various aspects of a multi-site injection system and method according to some embodiments. [Figure 74] FIG. 74 illustrates various aspects of a multi-site injection system and method according to some embodiments.

[0030] 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

[0031] Exemplary Multi-Site Infusion System Many injectable medications can be administered to multiple injection sites on the same patient. Some medical procedures involve injecting a fixed volume (e.g., 0.1 ml and / or microdoses) of a medication (e.g., botulinum toxin, or "Botox") into multiple injection sites on a patient. Currently, many medications are loaded into an injection system from a vial, which increases procedure time and exposes the needle to unintentional needle sticks. Furthermore, some medications are delivered in viscous solutions, necessitating the use of a large-diameter needle (e.g., low-gauge: 25 g) to draw the viscous medication into the injection system and a smaller-diameter needle (e.g., high-gauge: 30 g, 32 g, 34 g, sub-34 g) for injection. This needle switching increases procedure time and the risk of unintentional needle sticks. The multi-site injection system described herein solves these problems of current systems.

[0032] FIGS. 6-15C illustrate a multi-site injection system 500 according to some embodiments. As shown in FIG. 6, the system 500 can be pre-filled with an injectable medication. The system 500 includes a syringe body 510, a needle assembly 590, a stopper member 520, a plunger member 550, and a finger flange 540. Many of these system components (e.g., the syringe body 510, the stopper member 520, and the needle member 590) can be off-the-shelf components, leveraging existing, relatively well-managed supply chains and corresponding assembly machinery and personnel. The syringe body 510 can be glass, metal, or a polymeric material such as COC, COP, polypropylene, polyethylene, or other syringe materials. The stopper member 520 can be a polymeric material such as rubber, e.g., butyl, chlorobutyl, or bromobutyl, or a thermoplastic elastomer. The stopper member 520 can be coated with a protective and / or lubricious coating, such as PTFE or other polymers. Pre-fabricated stopper member 520 refers to a commercially available stopper member having a generally smooth distally facing surface that does not include protrusions or recesses for coupling to a needle. System 500 also includes plunger tube 560 configured to apply a distally facing force to plunger member 550 and coupled stopper member 520.

[0033] Figure 7 is an exploded view, Figures 8 and 9 are detailed perspective views, and Figures 10 and 11 are detailed partial longitudinal cross-sectional views, all of which show various internal components of multi-site injection system 500 according to some embodiments. Finger flange 540 includes ratchet pawl 542, lever arm 544, link 546, and return spring 548, all housed within flange housing 549. Plunger tube 560 includes arm 562 and thumb pad 564. Plunger member 550 includes ratchet face 552 having a plurality of teeth 554.

[0034] When assembled as shown in FIGS. 8-11 , thumb pad 564 is operatively coupled to ratchet pawl 542 via plunger tube 560, arm 562, link 546, and lever arm 544. Thus, when a distally directed force is applied to thumb pad 564, lever arm 544 transmits an increasing distally directed force to ratchet pawl 542. Depending on the relative dimensions of lever arm 544, the ratio of the distances traveled by plunger tube 560 and plunger member 550 can be anywhere from about 1 to about 5. In one embodiment, the distance ratio is about 2.5:1. Similarly, the force ratio between the force applied to thumb pad 564 and the force acting on ratchet pawl 542 can be anywhere from about 1 to about 5. In one embodiment, the force ratio is about 2.5:1.

[0035] A return spring 548 biases the lever in a proximal direction. Thus, when a user depresses thumb pad 564 to move plunger tube 560 distally and then releases pressure on thumb pad 564, thumb pad 564 and plunger 562 can return to their proximal positions. As shown in FIGS. 10 and 11 , ratchet pawl 542 includes a reduced diameter portion 543 at its distal end. This reduced diameter portion 543 interferes with teeth 554 on a ratchet surface 552 of plunger member 550, allowing ratchet pawl 542 to move proximally but not distally relative to plunger member 550. In the distal direction, ratchet pawl 542 can exert a force on plunger member 550. As shown in FIG. 9 , ratchet pawl 542 further includes a plurality of slots 561 configured to radially expand reduced diameter portion 543 upon return of plunger tube 560, allowing ratchet pawl 542 to engage ratchet teeth 554 of the next adjacent plunger member 550. When return spring 548 moves ratchet pawl 542 proximally, reduced diameter portion 543 and slots 561 are configured to allow ratchet pawl 542 to move proximally over plunger member 550. Lever arm 544 is configured to move ratchet pawl 542 from a distal position to a proximal position, thereby moving reduced diameter portion 543 proximally from one tooth 554 to the next tooth 554, thereby moving plunger member 550 distally the distance of one tooth 554. The various components of the system 500 can be configured so that distal movement of the plunger member 550 the distance of one tooth 554 expels a preset amount of fluid (e.g., 0.1 ml, a microdose) from within the syringe body 510. The spacing between the ribs / teeth 554 can be constant along the length of the plunger member 550 to deliver a consistent dose per injection, or can vary along the length of the plunger member 550 to deliver different doses per injection.As a result, by alternately depressing and releasing the thumb pad 564, the user can sequentially advance the plunger member 550 within the syringe body 510 to expel preset amounts of fluid.

[0036] 12-14 illustrate assembly of a multi-site injection system 500 according to some embodiments. In FIG. 12, the plunger tube 560 is inserted coaxially around the ratchet pawl 542 into the finger flange 500 until the arm 562 of the plunger tube 560 engages the link 546 attached to the lever arm 544. The finger flange 540 is snapped onto the pre-filled, pre-stoppered syringe 510. The plunger rod 550 is then inserted through the plunger tube 560 into the finger flange 540 and coupled (e.g., threaded or pushed) to the stopper member 520. The thumb pad 564 is then snapped onto the plunger tube 560 to complete the assembly. The system 500 shown in FIGS. 12-14 includes a pre-attached stake-shaped needle 592. The needle 592 is provided to the end user covered with a needle shield 595. The needle shield 595 may be constructed from a rubber inner needle-contacting component and a plastic outer cover. Alternative needles may be user-attached luer-type or pre-attached retractable safety needles.

[0037] 13 , the lateral opening of the finger flange 540 slides over the glass flange of the syringe body 510, removably coupling the finger flange 540 to the syringe body 510. The plunger member 550 is inserted through the finger flange 540, plunger tube 560, and ratchet pawl 542 until the reduced diameter portion 543 of the ratchet pawl 542 engages the distal-most tooth 554 of the plunger member 550. This engagement can be determined by either distance, sound, and / or a tactile indicator that the reduced diameter portion 543 has moved over the distal-most tooth 554 of the elongate member 550.

[0038] 14, thumb pad 564 is coupled to the proximal end of plunger tube 560 to complete the assembly. After thumb pad 564 is coupled to plunger tube 560, multi-site injection system 500 is ready for use. Needle shield 595 is removed to perform the injection.

[0039] 15A-15C illustrate the use of the multi-site injection system 500 shown in FIGS. 6-14 to inject a first of multiple doses (e.g., microdoses). In FIG. 15A, the multi-site injection system 500 is assembled and ready for use. The return spring 548 biases the lever arm 542 to a proximal position. The plunger member 550 has been inserted until the distal-most tooth 554A moves distally and engages the reduced diameter portion 543 of the ratchet pawl 542.

[0040] 15B illustrates the result of a user applying a distal force to thumb pad 564. The distal force is transmitted through arm 562 at the distal end of plunger tube 562 to link 546 and then to lever arm 544, causing the lever arm to move from its proximal position (see FIG. 15A) to its distal position (see FIG. 15B). As lever arm 544 moves from its proximal position to its distal position, ratchet pawl 542 moves distally relative to finger flange 540 and its coupled syringe body 510. Interference between reduced diameter portion 543 of ratchet pawl 542 and distal-most tooth 554A causes plunger member 550 to move distally with ratchet pawl 542. Because the ratchet pawl 542 and plunger member 550 move distally a shorter distance than the plunger tube 560, a space 566 exists at the proximal end of the plunger tube 560 to accommodate movement of the proximal end of the plunger member 550 as the plunger tube 560 moves distally over the plunger member 550. As the plunger member 550 moves distally relative to the syringe body 510, the stopper member 520 coupled thereto also moves distally relative to the syringe body 510, thereby expelling a fixed dose of fluid from the syringe body 510 through the needle assembly 590.

[0041] FIG. 15C shows the result of a user releasing the distal force from thumb pad 564. Return spring 548 moves lever arm 544 from its distal position (see FIG. 15B) to its proximal position (see FIG. 15C). Proximal movement of lever arm 544 causes both ratchet pawl 542 and plunger tube 560 to move proximally. As ratchet pawl 542 moves proximally, the elastic nature of its reduced diameter portion 543 causes it to expand and slide proximally over the second-to-distal most angled tooth 554B. System 500 is configured so that depression of thumb pad 564 and plunger tube 560, respectively, moves plunger member 550 distally the distance of one tooth 554. This causes reduced diameter portion 543 of ratchet pawl 542 to engage the next distal tooth 554 (ie, 554B) on plunger member 550 after lever arm 544 has returned to its proximal position.

[0042] 15C is now ready for another injection. The injection process shown in FIGS. 15A-15C can be repeated to perform a series of injections of a fixed volume (e.g., 0.1 ml, microdoses) until the plunger member 550 moves distally to a position where the proximal-most tooth 554 moves distally and no longer engages the reduced diameter portion 543 of the ratchet pawl 542. Although not shown, after the multi-site injection system 500 performs the last injection, the needle 592 in the needle assembly 590 is fully retracted proximally, through the stopper member 520 and at least partially into the plunger member 550, such that the sharp end of the needle 592 is no longer exposed, to minimize unintentional needle sticks.

[0043] 16-28 illustrate a multi-site injection system 700 according to some embodiments. As shown in FIGS. 16, 17, and 25-27, the system 700 includes a syringe body 710, a needle assembly 790, a needle cover 730, a stopper member 720, a plunger member 750, a finger flange 740, and a proximal tube 742. Many of these system components (e.g., the syringe body 710, the stopper member 720, and the needle cover 730) may be off-the-shelf components to take advantage of existing, relatively well-controlled supply chains and corresponding assembly machinery and personnel. The syringe body 710 may be glass, metal, or a polymeric material such as COC, COP, polypropylene, polyethylene, or other syringe materials. The stopper member 720 may be a polymeric material such as rubber, e.g., butyl, chlorobutyl, bromobutyl, or a thermoplastic elastomer. The stopper may be covered with a protective and / or lubricious coating, such as PTFE or other polymer. Pre-fabricated stopper member 720 refers to a commercially available stopper member having a generally smooth, distally-facing surface that does not include any protrusions or recesses for coupling to a needle. Proximal tube 742 includes a thumb pad 744 coupled to its proximal end to facilitate a user applying a distally-facing force to proximal tube 742, plunger member 750, and coupled stopper member 720. As described below, system 700 can also include an injectable fluid (e.g., a medication) disposed in syringe body 710.

[0044] As shown in FIGS. 17-20C , the finger flange 740 includes a ratchet mechanism including a proximal tube 742 extending proximally therefrom. The ratchet mechanism also includes a ratchet tube 760 and a plunger member 750 coaxially disposed inside the proximal tube 742. The plunger member 750 includes a plurality of serrated ribs / teeth 752 arranged in series along its longitudinal axis (see FIGS. 20A-20C ). The ratchet tube 760 includes a plurality (e.g., four) of elastically deformable leaves 762 operably coupled to the serrated ribs 752 of the plunger member 750. In an alternative embodiment, the ratchet tube 760 may include a single elastically deformable leaf 762. The ratchet mechanism further includes a return spring 748 that biases the ratchet tube 760 to a proximal position in which a flange 766 on the proximal end of the ratchet tube 760 is spaced from the proximal end of the proximal tube 742 (see FIG. 17).

[0045] The leaves 762 interfere with ribs / tooth 752 on the plunger member 750, allowing the ratchet tube 760 to move proximally but not distally relative to the plunger member 750. In the distal direction, the ratchet tube 760 can exert a force on the plunger member 750. When the return spring 748 moves the ratchet tube 760 proximally, the leaves 762 flex radially inward, allowing the ratchet tube 760 to move proximally over the plunger member 750. The system 700 is configured such that moving the ratchet tube 760 from a distal position to a proximal position moves the leaves 762 proximally from one rib / tooth 752 to the next rib / tooth 752. This moves the plunger member 750 distally the distance of one rib / tooth 752. The various components of system 500 can be configured to expel a volume (e.g., 0.1 ml, a microdose) of fluid from within syringe body 710 by distally moving plunger member 750 a distance of one rib / tooth 752. As a result, by alternately depressing and releasing thumb pad 744, a user can sequentially advance plunger member 750 within syringe body 710 to expel a preset amount of fluid.

[0046] 18 shows a finger flange 740 for use in the multi-site injection system 700. A proximal tube 742 aligns the ratchet tube 760 and plunger member 750 of the ratchet mechanism. The proximal tube 742 also has a proximal end 741 that provides a hard stop against a flange 766 on the proximal end of the ratchet tube 760. The distance between the proximal end of the proximal tube 742 and the flange 766 on the proximal end of the ratchet tube 760 defines the amount of travel of the plunger member 750 per injection. The proximal tube 742 also includes multiple (e.g., two) windows 746 configured to interfere with a retaining tab 768 on the ratchet tube 760.

[0047] 19 illustrates a ratchet tube 760 for use in the multi-site injection system 700. The ratchet tube 760 includes multiple (e.g., four) resilient leaves 762 configured to interfere with ribs / teeth 752 on the plunger member 750. In an alternative embodiment, the ratchet tube 760 can include a single resiliently deformable leaf 762. The ratchet tube 760 also includes multiple (e.g., two) retaining tabs 768 configured to extend to interfere with the window 746 and the proximal tube 742. In an alternative embodiment, the ratchet tube 760 can include a single retaining tab 768. The ratchet tube 760 further includes a flange 766 configured to interfere with the proximal end of the proximal tube 742 to define a single injection stroke.

[0048] 20A-20C show a plunger member 750 for use with the multi-site injection system 700. The plunger member 750 includes a pattern of continuous, serrated ribs / teeth 752 on its exterior surface. The spacing between the ribs / teeth 752 can be varied to adjust the dose delivered by the multi-site injection system 700. The spacing between the ribs / teeth 752 can be constant along the length of the plunger member 750 to deliver a consistent dose per injection, or the spacing can vary along the length of the plunger member 750 to deliver different doses per injection. The plunger member 750 also includes a needle retraction mechanism.

[0049] 21 and 22 show the proximal and distal positions of the ratchet tube 760 relative to the proximal tube 742 of the finger flange 740. In the proximal position shown in FIG. 21, the return spring 748 pushes the ratchet tube 760 proximally until the retaining tab 768 on the ratchet tube 760 interferes with the window 746 in the proximal tube 742. In the distal position shown in FIG. 22, the user applies a distal force to the thumb pad 744, pushing the ratchet tube 760 proximally until the flange 766 on the ratchet tube 760 interferes with the proximal end of the proximal tube 742. This mechanism defines the stroke length of the dose injection, thereby reducing overdose situations.

[0050] 23A-23C and 24A-24C illustrate one injection cycle using the multi-site injection system 700. In FIGS. 23A and 24A, the leaf 762 on the ratchet tube 760 engages the first serrated rib / tooth 752 on the plunger member 750, and the system 700 is ready for the first injection. When the user depresses the thumb pad 744, the leaf 762 transmits a distally directed force to the rib / tooth 752, thereby advancing the plunger member 750 and its associated stopper member 720 the distance of approximately one rib / tooth 752. The advancement of the stopper member 720 expels a volume (e.g., 0.1 ml, a microdose) of fluid from within the syringe body 710.

[0051] 23B and 24B, the user is depressing the thumb pad 744 as described above. Advancing the ratchet tube 760 also compresses the return spring 748. The interference between the flange 766 of the ratchet tube 760 and the proximal end of the proximal tube 742 defines the stroke length and can reduce overdose situations. The ratchet tube 760 also includes a space 764 at its proximal end to accommodate the proximal end of the plunger member 750 at the bottom of the first stroke.

[0052] 23C and 24C, the user has released the thumb pad 744. The return spring 748 expands, moving the ratchet tube 760 proximally on the plunger member 750, which is held in place by friction between the stopper member 720 and the syringe body 710. As the tube 760 moves proximally, the resiliently deformable leaf 762 slides over the serrated ribs / tooths 752, moving from the first rib / tooth 752 to the next proximal rib / tooth 752. This returns the ratchet tube 760 and thumb pad 744 to a ready position for the next injection, while the plunger member 750 remains in a position advanced the distance of one rib / tooth 752.

[0053] 23A-24C can be repeated to perform a series of injections of a volume (e.g., 0.1 ml, microdoses) until the plunger member 750 moves distally to a position where the proximal-most rib / tooth 752 moves distally past and out of engagement with the leaf 762 of the ratchet tube 760. As shown in FIG. 17 and 23A-24C, after the multi-site injection system 700 delivers its final injection dose, the needle 792 of the needle assembly 790 is fully retracted proximally through the stopper member 720 and at least partially within the plunger member 750 such that the sharp end of the needle 792 is no longer exposed to minimize unintentional needle sticks.

[0054] FIG. 27 illustrates the assembly of a multi-site injection system 700 according to some embodiments. A syringe body 710 is coupled to a needle assembly (not shown; see 790 in FIG. 26 ) and has a needle shield 795 over its distal end. The syringe body 710 is pre-filled with an injectable fluid (e.g., a medication) and pre-loaded with a stopper member 720. A finger flange 740 is then coupled (e.g., snapped) to the syringe flange of the syringe body 710. A plunger member 750 is then inserted through the proximal opening of a ratchet tube 760 and coupled (e.g., threaded) to the stopper member 720. Optionally, the proximal opening of the ratchet tube 760 is sealed, thereby obtaining the assembled multi-site injection system 700.

[0055] 28 illustrates a needle assembly 790 for use in a multiple-site injection system 700 according to some embodiments. The needle assembly 790 includes a needle latch 792. The needle latch assembly 790 also includes a retaining ring 794.

[0056] Figures 29-36 illustrate a multi-site injection system 700' according to some embodiments. The system 700' illustrated in Figures 29-36 is similar to the system 700 illustrated in Figures 16-28, and the same components are described above. The difference between the system 700' illustrated in Figures 29-36 and the system 700 illustrated in Figures 16-28 is that the system 700' illustrated in Figures 29-36 includes a stake-type needle assembly 790' that is not retractable. As such, the plunger member 750' does not include a needle retraction component. As shown in Figures 30 and 31, the plunger member 750' may be solid (e.g., polymeric).

[0057] Figure 32 shows an exploded view of system 700' with components identical to those of system 700 shown in Figures 16-28, which are numbered the same. Figure 33 shows a ratchet tube 760 identical to ratchet tube 760 in system 700 shown in Figures 16-28. Figure 34 shows a solid plunger member 750'.

[0058] 35 and 36 show partial assembly of a finger flange 740 / ratchet tube 760 unit according to some embodiments. First, the return spring 748 is inserted into the proximal tube 742 of the finger flange 740. Next, the ratchet tube 760 is inserted into the proximal tube 742 of the finger flange 740. The finger flange 740 / ratchet tube 760 unit is then attached to the glass / syringe flange of the syringe body, after which the plunger member 750' is inserted through the ratchet tube 760 and coupled to the stopper member within the syringe body. Optionally, the proximal end of the ratchet tube 760 is closed / sealed.

[0059] 37-42B illustrate several components for controllably advancing a plunger member 750′ of a multi-site injection system 700′ according to some embodiments to remove air from a syringe body (“defoaming” or “priming”) and move a portion of the injectable fluid into a needle. This process (“priming”) is particularly useful for microdose multi-site injection systems. As shown in FIGS. 37-39 and 41A-41B, the system 700′ includes a priming screw 761 coupled to a ratchet tube 760 by a threaded connection that translates rotation of the priming screw 761 into distal movement thereof. The priming screw 761 abuts the proximal end of the plunger member 750′ such that distal movement of the priming screw 761 moves the plunger member 750′ distally. The sealed priming screw 761 defines a rectangular drive recess 763 ( FIGS. 41A-41B ). Thumb pad 744 includes a rectangular drive boss 745 (FIGS. 42A and 42B) that mates with and interferes with a rectangular drive recess 763 to rotate seal member 761 and distally advance priming screw 761, thereby driving plunger member 750' and associated stopper member distally to expel air and fluid from the needle of system 700'. As shown in FIGS. 37, 38, and 40, ratchet tube 760 includes a plurality (e.g., four) latches 798 configured to couple thumb pad 744 to ratchet tube 760.

[0060] 43-47C illustrate several components for limiting proximal movement of a plunger member 750" of a multiple-site injection system 700", according to some embodiments. As shown in FIGS. 43-46, the finger flange 740" of the system 700" defines a chamber 747 configured to retain an anti-retraction mechanism 749. As shown in FIGS. 47A-47C, the anti-retraction mechanism 749 includes a pair of brake tabs 796 configured to limit proximal movement of the plunger tube 750" relative to the anti-retraction mechanism 749 while allowing distal movement relative to the anti-retraction mechanism 749.

[0061] FIGS. 48-54 illustrate a multi-site injection system 700'" according to some embodiments. The system 700'" illustrated in FIGS. 48-54 is similar to the system 700 illustrated in FIGS. 16-28, and the same components are described above. The difference between the system 700'" illustrated in FIGS. 48-54 and the system 700 illustrated in FIGS. 16-28 is that the system 700'" illustrated in FIGS. 48-54 includes a toothless plunger member 750'" (compared to the plunger member 750 of the system 700 illustrated in FIGS. 16-28). Instead of using teeth to ratchet the plunger member 750'" forward, a ratchet tube 760'" includes a pair of resiliently deformable metallic leaves 762'" configured to deform a softer surface of the plunger member 750'". The leaves may be formed of a polymer.

[0062] 52A-52C illustrate a single injection of a multi-site injection method using system 700'". As ratchet tube 760'" is pushed distally, resiliently deformable leaves 762'" bite into the surface of plunger member 750'", moving plunger member 750'" distally. At the end of the injection, a return spring pushes ratchet tube 760'" proximally while plunger member 750'" is held in place by friction or by the anti-retraction mechanism described above. Because plunger member 750'" does not have teeth, multi-site injection system 700'" can be used to deliver a less-than-full dose without disrupting the next injection dose by advancing ratchet tube 760'" a less-than-full stroke before releasing ratchet tube 760'".

[0063] Figures 55-67 illustrate a multiple-site injection system 500' according to some embodiments. The system 500' shown in Figures 55-67 is similar to the system 500 shown in Figures 6-15C, and the same components are described above. The difference between the system 500' shown in Figures 55-67 and the system 500 shown in Figures 6-15C is that the system 500' shown in Figures 55-67 includes a needle retraction mechanism.

[0064] To facilitate needle retraction, needle assembly 590' includes a removably coupled needle 592', and plunger member 550' includes a needle retraction member similar to that of the aforementioned patent application. As shown in FIGS. 60 and 61 , finger flange 540 includes an anti-retraction mechanism 541 configured to allow distal movement of plunger tube 550' relative to anti-retraction mechanism 541 while limiting proximal movement relative to anti-retraction mechanism 541. Anti-retraction mechanism 541 includes a pair of brake tabs 543, as shown in FIG. 61 .

[0065] 64-66 illustrate one injection cycle of a multi-site injection method using system 500'. As ratchet tube 560 is moved distally from FIG. 64 to FIG. 65, plunger member 550' is moved distally, expelling one dose from syringe body 510. When the user removes pressure from the thumb pad, a spring in the finger flange returns ratchet tube 560 proximally, preparing system 500' for the next injection / dose.

[0066] Figure 57 shows the plunger member 550' and stopper member 520 advanced nearly to the distal end of the syringe body 510, leaving only one dose inside the syringe body 510. After the final dose inside the syringe body 510 has been delivered, as shown in Figures 58 and 67, a retraction mechanism retracts the needle 592' into the plunger member 550' to minimize the risk of an accidental needle stick.

[0067] 59A and 59B show the finger flange assembly 540 before it is snapped onto the syringe body. The finger flange assembly 540 is attached to the syringe body in a manner similar to the finger flanges described in FIGS. 12 and 13. The finger flange assembly 540 includes a plunger tube 560 having an integral thumb pad 564 with an open proximal end 563 for insertion of a plunger member to couple to a stopper. The proximal end of the integral thumb pad 564 can be sealed with a plug after insertion of the plunger member.

[0068] FIG. 63 illustrates the plunger member 550′ and its components in an exploded view. Specifically, a plunger cap 556 is disposed on the proximal end of the plunger member 550′. The plunger cap 556 includes a drive recess 557 configured to facilitate rotation of the plunger member 550′ for threadedly coupling the plunger member 550′ to the stopper member. The plunger cap 556 also includes a pair of latches 558 configured to interfere with corresponding openings in the plunger member 550′ to secure the plunger cap 556. Securing the plunger cap 556 to the plunger member 550′ accommodates the needle retraction components (e.g., the needle, spring, spring latch, and needle receiver member) within the plunger member 550′ after needle retraction.

[0069] 68-74 illustrate a multi-site injection system 600 according to some embodiments. As shown in FIGS. 68 and 69, the system 600 includes a syringe body 610, a needle assembly 690, a needle cover 630, a stopper member 620, a plunger member 650, and a finger flange 640. Many of these system components (e.g., the syringe body 610, the stopper member 620, and the needle cover 630) may be off-the-shelf components to take advantage of existing, relatively well-controlled supply chains and corresponding assembly machinery and personnel. The plunger member 650 includes a thumb pad 654 coupled to its proximal end to facilitate a user applying a distally directed force to the plunger member 650 and the associated stopper member 620. As described below, the system 600 also includes an injectable fluid (e.g., a medication) disposed within a chamber of the plunger member 650.

[0070] 70 and 71 show the multiple-site injection system 600 with and without the needle cover 630 installed. With the needle cover 630 removed, as shown in FIG. 71, the system 600 is ready for use. As shown in FIGS. 70 and 71, the plunger member 650 also includes a proximal chamber 652 that can store an injectable fluid. The proximal chamber 652 opens at a distal end 656 of the plunger member 650.

[0071] As shown in FIG. 72 , the distal end 656 of the plunger member 650 defines a distally facing cone having an open bud approximately at its center. The stopper member 620 includes an internal cavity 622 in which the distal end 656 of the plunger member 650 is movably disposed. The stopper member 620 also includes a proximally facing protrusion 624 and an opening 628. The distal end 656 of the plunger member 650, the internal cavity 622, and the proximally facing protrusion 624 of the stopper member 620 together form a proximal one-way valve 626. The proximal one-way valve 626 is fluidly coupled between a proximal chamber 652 within the plunger member 650 and a distal chamber 612 defined by the stopper member 620 and the distal end of the syringe body 610. 72 , the proximal one-way valve 626 is open because the distal end 656 of the plunger member 650 is pulled proximally away from the proximally-facing protrusion 624 while the stopper member 620 is pulled distally away due to sliding friction between the stopper member 620 and the syringe body 610 and the vacuum in the distal chamber 612, thereby creating a fluid path between the opening in the distal end 656 of the plunger member 650 and the opening 628 in the stopper member 620. The proximal one-way valve 626 can be placed in a closed configuration by applying a proximally-facing force to the plunger member 650 to pull the distal end 656 of the plunger member 650 away from the proximally-facing protrusion 624 of the stopper member 620, as described below.

[0072] As also shown in FIG. 72 , the proximal end of the needle assembly 690 includes a distal one-way valve 694. The distal one-way valve 694 includes a spherical member 696 within a valve body 697 and a valve spring 698 that biases the spherical member 696 proximally to close the proximal opening of the valve body 697. In FIG. 72 , the distal one-way valve 694 is in a closed configuration. As shown in FIGS. 73 and 74 , upon continued application of a distal force to the plunger member 650 and the stopper member 620, the incompressible fluid within the distal chamber 612 transfers a force to the spherical member 696, overcoming the force of the valve spring 698 and moving the spherical member 696 distally, opening the distal one-way valve 694. Opening the distal one-way valve 694 fluidly couples the distal chamber 612 to the injection needle 692. The specific valve in this embodiment is exemplary. Other types of one-way valves are within the scope of this disclosure.

[0073] As shown in FIGS. 71 and 73 , finger flange 640 includes a return spring 642 that biases plunger member 650 toward a proximal position (see, e.g., FIG. 71 ). When a user applies a distal force to thumb pad 654 to perform an injection, the distal force overcomes the proximal force exerted by return spring 642 on thumb pad 654, advancing plunger member 650 a predetermined distance to the distal position (see, e.g., FIG. 73 ). Movement of plunger member 650 from the proximal to the distal position at stopper member 620 expels a known volume (e.g., 0.1 ml, a microdose) from distal chamber 612 through needle 692. A range of volumes (e.g., up to 0.1 ml) can also be expelled from distal chamber 612 by moving plunger member 650 only a portion of the distance to the distal position. When the plunger member 650 is advanced to perform an injection, the proximal one-way valve 626 is closed to prevent retrograde movement of fluid from the distal chamber 612 to the proximal chamber 652. In the configuration shown in FIG. 74 , the proximal one-way valve 626 is closed because the cone of the distal end 656 of the plunger member 650 is forced against the proximally-facing protrusion 624, thereby closing the opening at the distal end 656 of the plunger member 650. The proximal one-way valve 626 can be placed in the closed configuration by applying a distal force to the plunger member 650 to force the distal end 656 of the plunger member 650 against the proximally-facing protrusion 624 of the stopper member 620. The stopper member 620 and proximally-facing protrusion 624 are held in place by friction between the stopper member 620 and the syringe body 610 and positive pressure within the distal chamber 612. At the same time, the distal one-way valve 694 is opened by the increased pressure in the distal chamber 612 , allowing fluid to be injected from the distal chamber 612 through the needle 692 .

[0074] When the user releases the thumb pad 654, the return spring 642 moves the plunger member 650 proximally back to its proximal position (see, e.g., FIG. 71 ). When the plunger member 650 returns to its proximal position (see, e.g., FIG. 72 ), the vacuum created in the distal chamber 612 and the bias of the valve spring 698 cause the distal one-way valve 694 to assume its closed configuration. Simultaneously, the distal end 656 of the plunger member 650 moves proximally out of the internal cavity 622 of the stopper member 620, opening the proximally-facing projection 624 and thereby opening the proximal one-way valve 626. This causes the injectable fluid in the proximal chamber 652 of the plunger member 650 to be drawn into the distal chamber 612 by the vacuum in the distal chamber created by the proximal movement of the stopper member 620. The movement of injectable fluid from the proximal chamber 652 to the distal chamber 612 prepares the multi-site injection system 600 for another injection. The injection process shown in Figures 71-74 can be repeated to perform a series of injections of fixed volumes (e.g., 0.1 ml, microdoses).

[0075] Thus, a user can perform a series of injections by alternately depressing and releasing thumb pad 654. In the embodiment shown in FIGS. 68-74, a user can optionally depress plunger member 650 less than its full travel distance (e.g., to deliver a half dose or a quarter dose). Regardless of how far plunger member 650 is depressed, the return stroke draws a sufficient amount of injectable fluid from proximal chamber 652 into distal chamber 612 in preparation for the next injection.

[0076] Although various embodiments have been described with particular connectors (e.g., slip and luer), the embodiments can be used with any known infusion system connector. Although various embodiments have been described with stake-type needles and needle connectors, the embodiments can be used with any known permanently coupled needle or needle connector system.

[0077] 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 the more broadly applicable features of the present invention. Various changes may be made in 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 invention. All such modifications are intended to be within the scope of the claims associated with this disclosure.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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 disclosure, 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.

[0082] 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 relating 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 relating to the present invention. It should be noted that such claims may be drafted to exclude any element. Thus, this statement is intended to serve as a precedent for using exclusive terms such as "solely," "only," etc., in connection with the recitation of claim elements, or for using a "negative" limitation.

[0083] 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.

[0084] 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 syringe body having a proximal end and a distal end, a syringe interior, and a syringe flange at the proximal end; an injectable fluid disposed within the syringe; a finger flange coupled to the syringe flange; a stopper member disposed inside the syringe; a plunger ratchet member coupled to the stopper member; a plunger tube coaxially disposed around at least a portion of the plunger ratchet member and operably coupled to the plunger ratchet member; The finger flange is A lever arm; a spring connected to a first end of the lever arm; a link connecting the plunger tube to a second end of the lever arm opposite the first end; the lever arm having a proximal position and a distal position; the spring biases the lever arm toward the proximal position; the lever arm, the spring, and the link are housed within a flange housing; the plunger tube having a proximal position corresponding to the proximal position of the lever arm and a distal position corresponding to the distal position of the lever arm; 1. An injection system comprising: a plunger tube configured to move from its proximal position to its distal position, the plunger tube moving from its proximal position to its distal position, and the plunger ratchet member moving distally relative to the finger flange.

2. 10. The system of claim 1, the plunger ratchet member is operably connected to the lever arm; The system, wherein the plunger tube is operatively connected to the lever arm.

3. 3. The system of claim 2, The system, wherein the plunger tube is coaxially disposed within the syringe body.

4. 10. The system of claim 1, The system, wherein the spring biases the plunger tube to a proximal position.

5. 10. The system of claim 1, The system, characterized in that the finger flange has a distal stop surface configured to limit distal movement of the plunger tube beyond a distal position to prevent more than a certain amount of fluid from being expelled from within the syringe.

6. 10. The system of claim 1, moving the plunger tube a first distance from its proximal position to its distal position, thereby moving the plunger ratchet member a second distance distally relative to the finger flange, thereby expelling the injectable fluid from the syringe body.

7. 7. The system of claim 6, The ratio of the first distance to the second distance is in the range of 1 to 5.

8. 8. The system of claim 7, The ratio of the first distance to the second distance is 2.

5.

9. 10. The system of claim 1, A system wherein application of a first force to the plunger tube applies a second force to the plunger ratchet member, the ratio of the second force to the first force being a force ratio.

10. 10. The system of claim 9, The force ratio is in the range of 1 to 5.

11. 11. The system of claim 10, The force ratio is 2.

5.

12. 10. The system of claim 9, The force ratio reduces the amount of force applied to the plunger tube to inject a viscous medication through a needle.

13. 10. The system of claim 1, The system, wherein the plunger tube and the plunger ratchet member define a space at a proximal end of the plunger tube when the plunger tube is in its proximal position.

14. 10. The system of claim 1, The system further includes a needle hub assembly coupled to the syringe body at a distal end, the needle assembly including a non-retractable needle and a luer hub.

15. 15. The system of claim 14, The system, wherein the needle is selected from the group consisting of a 30g needle, a 32g needle, a 34g needle, and a sub-34g needle.

16. 10. The system of claim 1, The plunger ratchet member is a needle retaining feature disposed within the plunger; an energy storage member disposed within the plunger; a latch member for the energy storage member disposed within the plunger; The system further includes a needle hub assembly coupled to the syringe body at a distal end, the needle assembly comprising: a needle having a needle proximal end feature; Hub and a needle latch member configured to selectively prevent the needle from moving proximally relative to the hub; wherein a latch member of the energy storage member is transformed from a latched state to an unlatched state in response to manipulation of the plunger tube, thereby permitting the needle to be at least partially retracted within the plunger.

17. 17. The system of claim 16, The system is configured such that the needle is retracted at least partially within the plunger, completely through the stopper member.

18. 17. The system of claim 16, The system of claim 1, wherein the energy storage member is interconnected between an inner surface of the plunger ratchet member and the needle retaining feature.

19. 17. The system of claim 16, the plunger ratchet member having a plurality of teeth disposed on an outer surface thereof; a distal end of the plunger tube having a reduced diameter portion configured to interfere with each of the plurality of teeth to prevent proximal movement of the plunger tube relative to the plunger ratchet member; the latching member of the energy storage member is configured to be converted from a latched state to an unlatched state after the reduced diameter portion of the plunger tube moves distally past a proximal-most tooth of the plurality of teeth.

20. 17. The system of claim 16, The system, wherein the needle is selected from the group consisting of a 30g needle, a 32g needle, a 34g needle, and a sub-34g needle.

21. 10. The system of claim 1, The system further comprising a thumb pad coupled to a proximal end of the plunger tube.

22. 10. The system of claim 1, the plunger ratchet member having a plurality of teeth disposed on an outer surface thereof; a distal end of the plunger tube having a reduced diameter portion configured to interfere with each of the plurality of teeth to prevent proximal movement of the plunger tube relative to the plunger ratchet member.

23. 23. The system of claim 22, The system further comprises a ratchet retaining member having a latch configured to interfere with a plurality of teeth of the plunger ratchet member to limit proximal movement of the plunger ratchet member relative to the ratchet retaining member.

24. 24. The system of claim 23, The ratchet retaining member includes a pair of resilient latches disposed on opposite sides thereof.

25. 24. The system of claim 23, The system wherein the ratchet retaining member is formed from sheet metal.

26. 24. The system of claim 23, The finger flange defines a space sized and shaped to retain the ratchet retaining member.

27. 27. The system of claim 26, The system wherein the finger flange also defines a side opening leading to the space.

28. 24. The system of claim 23, A system characterized in that the tooth pitch is sized to provide a consistent injection dose from tooth to tooth.

29. 23. The system of claim 22, The system wherein the plurality of teeth comprises ten teeth.

30. 23. The system of claim 22, The system of claim 1, wherein the reduced diameter section includes a plurality of leaves oriented along a longitudinal axis of the plunger tube.

31. 31. The system of claim 30, The system, wherein the plurality of leaves consists of four leaves.

32. 10. The system of claim 1, A system wherein moving the plunger tube from its proximal position to its distal position expels a volume of fluid from within the syringe.

33. 33. The system of claim 32, The system further comprises a finger flange having a distal stop surface configured to limit distal movement of the plunger tube beyond a distal position to prevent more than the predetermined amount of fluid from being expelled from within the syringe.

34. 33. The system of claim 32, The system is characterized in that the fixed volume is 0.1 ml.

35. 10. The system of claim 1, The system, wherein the stop member is a prefabricated stop member.

36. 10. The system of claim 1, The system, wherein the syringe body is a pre-fabricated syringe body.

37. 10. The system of claim 1, The plunger ratchet member defines a drive recess at a proximal end thereof.

38. 10. The system of claim 1, The finger flange is a proximally extending tube coaxially disposed about a portion of the plunger tube; a return spring configured to bias the plunger tube from a distal position to a proximal position.

39. 39. The system of claim 38, The system, wherein the plunger tube comprises a proximal flange configured to limit distal movement of the plunger tube relative to the proximally extending tube of the finger flange.

40. 39. The system of claim 38, the plunger tube includes a plurality of tabs oriented away from a longitudinal axis of the plunger tube; the proximally extending tube of the finger flange defines a corresponding plurality of windows configured to interfere with the plurality of tabs to limit proximal movement of the plunger tube relative to the proximally extending tube of the finger flange.

41. 10. The system of claim 1, The system, wherein the plunger tube is coaxially disposed within the syringe body.

42. 10. The system of claim 1, The system further comprises a priming screw configured to advance the plunger ratchet member to remove air from within the syringe and expel a portion of the injectable fluid from within the syringe.

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