Needleless syringe

Abstract

To provide a needleless syringe capable of reducing sound transmission caused by gas serving as a power source.SOLUTION: A needleless syringe 1 includes: a cylinder 10 having a first end portion 1a and a second end portion 1b formed with a delivery hole 100 for dermal administration of liquid to a living body; a cylindrical body housing 3; a plunger 8; a pressing member 6; a tank 5; a trigger member 2; and a cover member 7. The cylinder defines a first space S1 formed with the delivery hole and being for storing liquid.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a needle-free syringe and a syringe unit. [Background technology]

[0002] Patent Document 1 discloses a needleless syringe. This needleless syringe includes an actuator cap that houses a power source, a main housing that is disposed on one end side of the actuator cap, and an ampoule containing a fluid that can be attached to one end side of the main housing. The power source is, for example, a gas, and is stored in the actuator cap in a sealed state before the needleless syringe is operated. A plunger shaft is disposed in the internal space of the main housing. The ampoule has an orifice for discharging a fluid at an end opposite to the main housing. When the ampoule is attached to the main housing, its internal space communicates with the internal space of the main housing. When the orifice is applied to tissue and the actuator cap is pushed toward the ampoule, the gas sealing mechanism is broken and the gas is discharged from the actuator cap into the internal space of the main housing. The discharged gas moves the plunger shaft toward the orifice. This causes the fluid in the ampoule to be discharged through the orifice and delivered below the surface of the tissue. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2005-536273 Summary of the Invention [Problem to be solved by the invention]

[0004] In the needleless syringe disclosed in Patent Document 1, when the gas of the power source is released, especially when it leaks out of the needleless syringe, a sound is generated due to the flow of the gas. This sound may startle a person or a non-human animal receiving a fluid transdermally using the needleless syringe, and may cause the person to move suddenly. As a result, the transdermal administration may not be performed properly. Patent Document 1 does not take this into consideration.

[0005] An object of the present invention is to provide a needle-free syringe and a syringe unit that can reduce the transmission of sound generated by gas that serves as a power source. [Means for solving the problem]

[0006] A needle-free syringe according to a first aspect of the present invention has a first end portion in which a delivery hole for transdermally administering a liquid to a living body is formed, and a second end portion opposite to the first end portion, and includes a cylinder, a cylindrical main body housing, a plunger, a pressing member, a tank, a trigger member, and a cover member. The cylinder has the delivery hole formed therein and defines a first space for containing the liquid. The cylindrical main body housing is connected to the cylinder at the second end side of the cylinder and defines a second space communicating with the first space. The plunger is movable within the first space and the second space. The pressing member is movable within the second space and presses the plunger from the second end side. The tank is disposed on the second end side of the pressing member in the second space and seals a substance. The trigger member is capable of destroying at least a part of the tank to release the substance as a gas into the second space and drive the pressing member. A cylindrical cover member covers at least a portion of the main housing from the outside. The cover member and the main housing form a sound reduction mechanism that reduces sound generated by the gas when the gas is released into the second space.

[0007] A needle-free syringe according to a second aspect of the present invention is the needle-free syringe according to the first aspect, wherein the main body housing has a through hole that communicates the second space with an external space of the main body housing, and the cover member has a side wall portion facing the through hole.

[0008] A needle-free syringe according to a third aspect of the present invention is the needle-free syringe according to the first or second aspect, wherein the trigger member is configured to be operated by application of an external force from outside the cover member and to be capable of destroying at least a part of the tank, and the cover member is configured to be movable between a lock position that restricts operation of the trigger member and a release position that releases the restriction on the operation of the trigger member.

[0009] A needle-free syringe according to a fourth aspect of the present invention is a needle-free syringe according to any one of the first to third aspects, wherein the trigger member has an insertion portion that penetrates the cover member and the main housing and is positioned in the second space, and when the cover member is located in the locked position, the insertion portion does not reach the tank, and when the cover member is located in the released position, the insertion portion reaches the tank due to an external force applied to the trigger member.

[0010] A needle-free syringe according to a fifth aspect of the present invention is the needle-free syringe according to any of the first to fourth aspects, wherein the side wall portion has an inner circumferential surface facing an outer circumferential surface of the main body housing and forming a space between the inner circumferential surface and the outer circumferential surface, and further comprises a filler filled in the space.

[0011] A needle-free syringe according to a sixth aspect of the present invention is the needle-free syringe according to any one of the first to fifth aspects, wherein the cylinder is configured to be detachable from the main body housing.

[0012] A needle-free syringe according to a seventh aspect of the present invention is the needle-free syringe according to any one of the first aspect to the sixth aspect, wherein the gas is carbon dioxide.

[0013] A syringe kit according to an eighth aspect of the present invention comprises the needle-free syringe according to any one of the first aspect to the seventh aspect, and a vial adapter connectable to the first end of the needle-free syringe.

[0014] A syringe unit according to a ninth aspect of the present invention is a syringe unit for constituting a needleless syringe having a first end portion in which a delivery hole for transdermally administering a liquid to a living body is formed, and a second end portion opposite to the first end portion, and includes a main body housing, a pressing member, a tank, a trigger member, and a cover member. The main body housing is a cylindrical main body housing in which the delivery hole is formed, is connected to the second end side of a cylinder that defines a first space for containing the liquid, and defines a second space communicating with the first space, and can accommodate a plunger that moves within the first space and the second space. The pressing member is movable within the second space and presses the plunger from the second end side. The tank is disposed on the second end side of the pressing member in the second space, and seals a substance. The trigger member is capable of breaking at least a part of the tank to release the substance as a gas into the second space and drive the pressing member. The cover member is cylindrical and covers at least a portion of the main housing from the outside. The cover member and the main housing form a sound reduction mechanism that reduces sound generated by the gas when the gas is released into the second space. Effect of the Invention

[0015] According to the needle-free syringe of the present invention, the transmission of sound generated by the gas serving as the power source can be reduced, and transdermal administration to a living body can be performed appropriately. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a cross-sectional view of a needleless syringe. [Diagram 2] FIG. 2 is an exploded perspective view of a needleless syringe and a vial adapter. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. 4 is a cross-sectional view of a main portion showing a configuration in the vicinity of a tip of an insertion portion. [Figure 7] FIG. [Figure 8] Cross-section of the tank. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 4 is a view of the cover member as viewed from the inner circumferential surface side. [Figure 12] 5A and 5B are diagrams illustrating the release position and the lock position of the cover member. [Figure 13] 6A and 6B are cross-sectional views illustrating the release position and the lock position of the cover member. [Figure 14] FIG. 2 is a cross-sectional view of the cylinder tip and the vial adapter. [Figure 15] 13 is a cross-sectional view showing a state in which the tip of the gasket has entered a tapered space. FIG. [Figure 16A] FIG. [Figure 16B] FIG. 13 is a diagram showing the configuration of another filler. [Figure 16C] FIG. 13 is a diagram showing the configuration of yet another filler material. [Figure 17A] FIG. 13 is a cross-sectional view of a needle-free syringe equipped with a cover member according to a modified example. [Figure 17B] FIG. 13 is a perspective view of a needle-free syringe including a cover member according to a modified example. [Figure 18A] 2 is a graph showing the sound level of the needle-free syringe according to Example 1. [Figure 18B] 6 is a graph showing the sound level of the needle-free syringe according to Example 2. [Figure 18C] 11 is a graph showing the sound level of the needle-free injector according to Example 3. [Figure 18D] 11 is a graph showing the sound level of the needle-free syringe according to Example 4. [Figure 18E] 11 is a graph showing the sound level of the needle-free injector according to Example 5. [Figure 18F] 13 is a graph showing sound levels of a needle-free injector according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a needle-free syringe according to one embodiment of the present invention will be described with reference to the drawings.

[0018] <1. Configuration of needleless syringe> FIG. 1 is a cross-sectional view of the needle-free syringe 1 according to the present embodiment, and FIG. 2 is an exploded perspective view of the needle-free syringe 1 and a vial adapter 11. The needle-free syringe 1 is a syringe for transdermally administering a liquid to a living body. The living body may be a human or an animal other than a human. The living body is preferably a mammal. The liquid to be transdermally administered is not particularly limited, and examples thereof include liquids containing medicines, vaccines, physiological saline, placebo, anesthetics, and the like. The liquid administered to the living body by the needle-free syringe 1 penetrates the outermost layer of the skin of the living body and reaches at least one of the skin tissue, subcutaneous tissue, and fascia. Since the needle-free syringe 1 does not include a needle, the liquid can be transdermally administered to the target human or animal without causing the target human or animal to feel pain from the skin being punctured. In addition, the needle-free syringe 1 can avoid the risk of infection caused by needlestick accidents. A needlestick accident is, for example, an accident in which the human or animal being injected moves unexpectedly, and the needle accidentally pierces a medical worker after puncturing the human or animal, or a used needle is not properly disposed of and a person accidentally comes into contact with it.

[0019] The needle-free syringe 1 extends along the axis A1 as a whole, and a delivery hole 100 for delivering the liquid is formed at one end in the axis A1 direction. Hereinafter, the end where the delivery hole 100 is formed may be referred to as the first end 1a of the needle-free syringe 1, and the end opposite to the first end 1a may be referred to as the second end 1b. The needle-free syringe 1 includes a main body housing 3, a trigger member 2, a lid body 4, a cover member 7, a tank 5, a pressing member 6, a plunger 8, and a cylinder 10. The trigger member 2, the lid body 4, and the cover member 7 are attached to the main body housing 3, and the tank 5 and the pressing member 6 are housed in the main body housing 3. As described later, the needle-free syringe 1 is formed by connecting a cylinder 10 (hereinafter, sometimes referred to as a cylinder unit) in which the plunger 8 is combined to a syringe unit including the main body housing 3. The configuration of each part of the needle-free syringe 1 will be described below.

[0020] [Cylinder] The cylinder 10 is a substantially cylindrical member with a delivery hole 100 formed at its tip, and defines a first space S1 extending in the direction of the axis A1. The first space S1 is a space for containing a liquid to be administered to a living body. The liquid in the first space S1 flows toward the delivery hole 100 as the plunger 8, which will be described later, moves within the first space S1. The first space S1 is circular when viewed from a cross section perpendicular to the axis A1.

[0021] 3 is a perspective view of the cylinder 10 according to this embodiment. The cylinder 10 has a delivery hole portion 101 in which the delivery hole 100 is formed, a substantially cylindrical side wall portion 102 continuing to the second end 1b side of the delivery hole portion 101, a base portion 103 continuing to the second end 1b side of the side wall portion 102, and a connection portion 104 continuing to the second end 1b side of the base portion 103.

[0022] The delivery hole portion 101 is a portion that is applied to the surface of a target living body when the liquid in the first space S1 is administered transdermally to the living body. In this embodiment, the delivery hole portion 101 has an appearance of a substantially truncated cone shape, but the appearance is not limited to this. The first space S1 is defined so that the diameter of the delivery hole portion 101 decreases from the second end 1b side to the first end 1a side, and the diameter is smallest at the delivery hole 100. Hereinafter, the space defined by the delivery hole portion 101 in the first space S1 may be referred to as a "tapered space S10". The tapered space S10 functions as an orifice when the liquid in the first space S1 is delivered to the outside. As a result, the liquid in the first space S1 is delivered through the delivery hole 100 with a pressure that penetrates the outermost layer of the living body.

[0023] The side wall portion 102 is a portion extending along the axis A1. The side wall portion 102 has two or more connected portions 1020 on the outer circumferential surface in the vicinity of the delivery hole portion 101. The side wall portion 102 is configured to be connectable to the vial adapter 11 described later through the two or more connected portions 1020, but the configuration of the side wall portion 102 is not limited thereto and can be modified as appropriate. In this embodiment, the connected portions 1020 are each formed as a protrusion that protrudes radially outward with respect to the axis A1 and extends in the circumferential direction. The protrusions are each formed at intervals in the circumferential direction with respect to the axis A1.

[0024] The base 103 is formed so that the outer diameter increases from the first end 1a side to the second end 1b side. The base 103 has an end face 1030 facing the second end 1b side. When the connecting portion 104 is screwed into the inside of the tip portion 30 of the main body housing 3 described later and the cylinder 10 moves toward the main body housing 3 by a certain amount, the end face 1030 faces and contacts the end face 300 of the main body housing 3. As a result, the end face 1030 restricts the connecting portion 104 from being further screwed into the tip portion 30. In other words, the end face 1030 functions as a stopper for properly screwing the connecting portion 104 into the tip portion 30. The tip portion 30 is an example of the "connected portion" in the present invention.

[0025] The connection part 104 is a substantially cylindrical part for connecting the main body housing 3 and the cylinder 10. In this embodiment, the connection mechanism between the main body housing 3 and the cylinder 10 is a screw type, but the connection mechanism is not limited to this. The connection part 104 in this embodiment has a screw thread 1040 formed on the cylindrical outer circumferential surface, and is configured to screw into a screw thread 301 formed on the inner circumferential surface of the tip part 30 of the main body housing 3.

[0026] The cylinder 10 of this embodiment is configured as one member. That is, the delivery hole portion 101, the side wall portion 102, the base portion 103, and the connection portion 104 are integrally formed. Therefore, as shown in FIG. 1, the side wall portion 102, the base portion 103, and the connection portion 104 form a continuous inner wall surface 105. The part of the first space S1 defined by the inner wall surface 105 has a constant inner diameter along the axis A1 direction. Hereinafter, the part of the first space S1 defined by the continuous inner wall surface 105 is also referred to as the "cylindrical space S11". The cylindrical space S11 is a space in which the plunger 8 described later mainly moves to push the liquid in the first space S1 toward the delivery hole 100.

[0027] The material from which the cylinder 10 is made is not particularly limited, but for example, a resin is preferable, and among them, from the viewpoint of ensuring sufficient impact resistance, gas barrier properties, and transparency, polycarbonate or a resin having equivalent impact resistance, etc. is preferable.

[0028] [Plunger] The plunger 8 is a substantially cylindrical member extending in the direction of the axis A1. The plunger 8 is used to suck liquid from a vial (not shown) into the first space S1 and to deliver the liquid from the first space S1 to a living body by moving within the first space S1 of the cylinder 10.

[0029] 4 is an exploded perspective view of the plunger 8. The plunger 8 has a plunger body 80 and a gasket 9 attached to a tip 800 on the first end 1a side of the plunger body 80. The gasket 9 is mainly made of rubber or elastomer. This gives the gasket 9 elasticity as a whole. At least a part of the surface of the gasket 9 may be covered with a resin film or the like that is inactive against the liquid to be administered transdermally.

[0030] The gasket 9 has a substantially cylindrical main body 90 and a tapered portion 91 extending continuously from the tip of the main body 90 on the first end 1a side. The tapered portion 91 has a tapered shape that reduces in diameter from the second end 1b side toward the first end 1a side. The tapered portion 91 has a shape and dimensions that fit along the inner wall surface of the delivery hole portion 101 that defines the tapered space S10 when the plunger 8 is pushed most toward the first end 1a side of the cylinder 10. This allows the liquid in the first space S1 to be more efficiently pushed out to the delivery hole 100 during transdermal administration, and prevents the liquid from remaining in the first space S1.

[0031] The main body 90 is configured such that, in a side view, the outer diameter is largest at the tip 900 on the first end 1a side and the rear end 901 on the second end 1b side, and the outer diameter is slightly smaller at an intermediate portion 902 located between the tip 900 and the rear end 901. When the plunger 8 is pushed from the second end 1b side to the first end 1a side to push the liquid in the first space S1 toward the delivery hole 100, the outer peripheral surface of the tip 900 mainly comes into close contact with the inner wall surface 105 that defines the cylindrical space S11 over the entire circumferential direction. This prevents the liquid from passing through the gap between the inner wall surface 105 and the outer peripheral surface of the main body 90 and flowing from the first end 1a side of the gasket 9 to the second end 1b side when the plunger 8 is pushed out. On the other hand, when the plunger 8 is pulled from the delivery hole 101 side of the cylinder 10 toward the connection part 104 side to introduce liquid into the first space S1, mainly the outer peripheral surface of the rear end part 901 comes into close contact with the inner wall surface 105 that defines the cylindrical space S11 over the entire circumferential direction. This prevents the liquid from passing through the gap between the inner wall surface 105 and the outer peripheral surface of the main body part 90 and flowing from the first end part 1a side to the second end part 1b side of the gasket 9 when the plunger 8 is pulled out.

[0032] A gasket space S9 is formed in the main body 90. The gasket space S9 is a space that is open on the second end 1b side of the main body 90 and closed on the first end 1a side. The gasket space S9 is configured to receive the tip 800 of the plunger main body 80 of the gasket 9 and to have a shape that fits the outer shape of the tip 800 by elastic deformation. When the entire tip 800 is accommodated in the gasket space, the gasket 9 is fixed to the tip 800, and the gasket 9 and the plunger main body 80 operate together as the plunger 8.

[0033] The shape of the gasket space S9 and the outer shape of the tip portion 800 are preferably such that the gasket 9 is prevented from easily separating from the tip portion 800. In this embodiment, the tip portion 800 has a shape that expands in diameter from the tip of the first end 1a toward the second end 1b, then contracts once at the midpoint in the axial A1 direction, and expands again from the first end 1a toward the second end 1b. By changing the outer diameter of the tip portion 800 along the axial A1 direction in this way, the gasket 9 can be fixed to the tip portion 800 more reliably.

[0034] The plunger body 80 has a rod-like outer shape extending along the axis A1 except for the tip portion 800. A rear end portion 801 on the second end portion 1b side of the plunger body 80 is pressed by a pressing member 6, which will be described later.

[0035] The material for forming the plunger body 80 is not particularly limited, but is preferably, for example, a resin, and among them, engineering plastics such as polycarbonate, cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polyethylene, polypropylene, etc. In addition, even if the tip portion 800 and the gasket 9 are formed from different materials, they may be molded integrally by a method such as two-color molding.

[0036] [Main body housing] 5 is an exploded perspective view of the main body housing 3 and the cover 4 that can be attached thereto. The main body housing 3 has a front end portion 30 which is an end portion on the first end portion 1a side, a rear end portion 31 which is an end portion on the second end portion 1b side, and an intermediate portion 32 which is continuous with the front end portion 30 and the rear end portion 31 and extends between them. The front end portion 30, the rear end portion 31, and the intermediate portion 32 each have a substantially cylindrical outer shape. In other words, the main body housing 3 is a substantially cylindrical member which extends along the axis A1 direction.

[0037] 1, the main housing 3 defines a second space S2 and a housing space S3, each of which is a substantially cylindrical space. The second space S2 and the housing space S3 are in communication with each other, with the second space S2 located on the first end 1a side and the housing space S3 located on the second end 1b side. The second space S2 and the housing space S3 are open at the ends (the front end 30 and the rear end 31) of the main housing 3, respectively.

[0038] The housing space S3 accommodates the tank 5, which will be described later. The housing space S3 according to this embodiment has a larger inner diameter than the second space S2. This restricts the movement of the tank 5 toward the first end 1a. The housing space S3 is closed at the second end 1b side by the lid 4 attached to the rear end 31. With the lid 4 attached to the rear end 31, the movement of the tank 5 toward the second end 1b side is also restricted. In other words, the main housing 3 and the lid 4 are configured to fix and position the tank 5 within the housing space S3.

[0039] The rear end 31 has a protrusion 310 on its outer circumferential surface that protrudes radially outward from the outer circumferential surface. The protrusion 310 is connected to the trigger member 2 described later and holds the trigger member 2 rotatably about an axis A2 perpendicular to the axis A1. More specifically, the protrusion 310 is formed in a middle portion in the axis A1 direction so as to define a groove 3100. The groove 3100 opens toward the radially outward direction based on the axis A1 and extends along the axis A2 direction. The groove 3100 receives and positions a support post 22 of the trigger member 2 described later. When the support post 22 is received by the groove 3100, it is fixed to the rear end 31 but can rotate based on the axis A2. This allows the trigger member 2 to be rotatably connected to the rear end 31.

[0040] The intermediate portion 32 has a protrusion 320 and a protrusion 321 on its outer circumferential surface, each of which protrudes radially outward from the outer circumferential surface. The intermediate portion 32 also has a through hole 322 formed therein, which penetrates the intermediate portion 32 in the radial direction based on the axis A1 and communicates the second space S2 with the external space of the main body housing 3. The protrusion 320, the through hole 322, and the protrusion 321 are arranged in this order from the second end 1b side toward the first end 1a side, and are arranged at the same circumferential position as the protrusion 310 on the outer circumferential surface of the main body housing 3. The protrusions 320 and the protrusions 321 are portions that are overlapped by a cover member 7 described later from the radial outside, and therefore have a shorter length of protrusion radially outward than the protrusion 310.

[0041] As described later, when the cover member 7 is located at the first lock position, the protrusions 320 and 321 respectively fit into recesses 720 and 721 (see FIG. 11) formed on the inner circumferential surface 72 of the cover member 7, thereby positioning the cover member 7 with respect to the main housing 3. When the cover member 7 is located at the release position, the protrusions 320 and 321 respectively fit into recesses 722 and 723 (see FIG. 11) formed on the inner circumferential surface 72 of the cover member 7, thereby positioning the cover member 7 with respect to the main housing 3. Furthermore, the protrusions 320 and 321 contact surfaces 724 and 725 of the inner circumferential surface 72 of the cover member 7 when the cover member 7 is located at a second lock position intermediate between the first lock position and the release position.

[0042] The through hole 322 penetrates the intermediate portion 32 in the radial direction based on the axis A1. The insertion portion 21 of the trigger member 2 described later is inserted into the through hole 322. FIG. 6 is a cross-sectional view of a main part showing a configuration near the tip of the insertion portion 21. The intermediate portion 32 has a rib 3260 protruding radially inward from the inner circumferential surface 326 in the vicinity of the through hole 322 on the first end 1a side of the insertion portion 21. The rib 3260 is continuous in the circumferential direction and is therefore annular when viewed from the axis A1 direction. The rib 3260 engages with a rib 600 (see FIG. 7) of the pressing member 6 described later, and restricts the pressing member 6 from moving in the second space S2 depending on the attitude of the needleless syringe 1 regardless of the substance of the tank 5.

[0043] Furthermore, the intermediate portion 32 has a step portion 323 where the outer diameter changes discontinuously on the first end 1a side from the protruding portion 321. The outer diameter of the intermediate portion 32 changes so that it is larger on the second end 1b side of the step portion 323 and smaller on the first end 1a side. As a result, a space S7 is formed between an inner circumferential surface 72 of the cover member 7 described later and an outer circumferential surface 324 of the intermediate portion 32 on the first end 1a side from the step portion 323 (see FIG. 1).

[0044] A through hole 325 is further formed in a portion of the intermediate portion 32 closer to the tip portion 30. The through hole 325 penetrates the intermediate portion 32 in a radial direction based on the axis A1, and communicates the second space S2 with the external space of the main body housing 3. The through hole 325 functions as a vent for releasing a substance discharged as a gas from the tank 5 into the second space S2 into the space S7. In order to ensure the power of the gas, the through hole 325 as the vent is preferably formed at a position on the main body housing 3 that is closer to the second end 1b than the rear end 62 of the pressing member 6 when the pressing member 6 described later moves to the most first end 1a side. Note that more through holes functioning as the vent may be formed in the intermediate portion 32.

[0045] On the outer peripheral surface of the tip portion 30, a rib 302 is formed on the first end 1a side of the through hole 325, protruding radially outward from the outer peripheral surface and extending in the direction of the axis A1. In this embodiment, two ribs 302 are formed at positions 180° apart in the circumferential direction with the axis A1 as a reference, but one rib 302 or three or more ribs may be formed. When the cover member 7 described later is located at the first lock position and the second lock position, the rib 302 fits into two grooves 726 (see FIG. 10) formed on the inner peripheral surface 72 of the cover member 7, respectively, to position the cover member 7 with respect to the main body housing 3.

[0046] As described above, the inner peripheral surface of the tip portion 30 is formed with the thread 301 that screws into the thread 1040 of the cylinder 10. The main body housing 3 is connected via the thread 1040 and the thread 301 to the cylinder 10, in which a liquid is contained in the first space S1 and in which at least a portion of the gasket 9 of the plunger 8 is contained in the cylindrical space S11.

[0047] The material from which the main housing 3 is formed is not particularly limited, but is preferably, for example, a resin, and in particular, a resin that has excellent impact resistance and can be ultrasonically welded is preferable, such as polycarbonate or a resin having equivalent impact resistance.

[0048] [Lid] After the tank 5 is accommodated in the housing space S3, the lid body 4 is attached to the rear end portion 31 of the main housing 3 in a manner such as fitting, and fixed by ultrasonic welding or the like. However, the method of attaching and fixing the lid body 4 is not limited to this. The lid body 4 of this embodiment has a substantially disk-shaped flange portion 41 and a substantially cylindrical fitting portion 40 protruding from a first surface 410 of the flange portion 41. The fitting portion 40 is configured to be fitted into the housing space S3 from the rear end portion 31 side of the main housing 3. The flange portion 41 is formed with a larger diameter than the rear end portion 31, and is configured so that when the entire fitting portion 40 is fitted into the housing space S3, the first surface 410 comes into contact with the end surface of the rear end portion 31. In addition, when the entire fitting portion 40 is fitted into the housing space S3, the end portion 400 of the fitting portion 40 comes into contact with the tank 5, restricting the tank 5 from moving toward the second end portion 1b side in the housing space S3.

[0049] The material for forming the lid 4 is not particularly limited, but is preferably, for example, a resin, and in particular, a resin that has excellent impact resistance and can be ultrasonically welded is preferable, such as polycarbonate or a resin having equivalent impact resistance.

[0050] [Pressing member] FIG. 7 is a perspective view of the pressing member 6. The pressing member 6 has a generally truncated cone shape that gradually decreases in diameter from the second end 1b side toward the first end 1a side, except for the rib 600 formed on the outer circumferential surface 60. The pressing member 6 is configured to receive gas discharged from the tank 5 into the second space S2, which will be described later, and move in the second space S2 while pressing the plunger 8. For this reason, the maximum outer diameter of the pressing member 6 is formed to be large enough to move in the second space S2 without interfering with the inner circumferential surface 326, except for the rib 600. On the other hand, it is preferable to make the gap between the inner circumferential surface 326 and the outer circumferential surface 60 of the pressing member 6 as small as possible in order to suppress the amount of gas discharged from the tank 5 passing through. Therefore, the maximum outer diameter of the pressing member 6 is formed to be slightly smaller than the inner diameter in the second space S2.

[0051] The rib 600 is formed on the rear end 62, which is the end of the pressing member 6 on the second end 1b side. The rib 600 protrudes radially outward from the outer circumferential surface 60 of the rear end 62 with respect to the axis A1. The rib 600 is continuous in the circumferential direction, and is therefore annular when viewed from the axis A1 direction. Before the gas in the tank 5 is released into the second space S2, the pressing member 6 is accommodated in the second space S2 so that the rib 600 is located closer to the second end 1b than the rib 3260 (see FIG. 6). As a result, before the gas in the tank 5 is released into the second space S2, the movement of the pressing member 6 in the second space S2 is restricted, and the pressing member 6 is positioned at an appropriate position in the second space S2. Hereinafter, the state in which the pressing member 6 is positioned in this manner will be referred to as the initial state of the needleless syringe 1. The strength of the engagement between the rib 3260 and the rib 600 in the initial state is preferably such that the engagement is not released by the weight of the pressing member 6 when the first end 1a of the needle-free syringe 1 faces vertically downward and the second end 1b faces vertically upward. On the other hand, the strength of the engagement is preferably such that the engagement is easily released when the pressing member 6 receives a driving force due to gas released from the tank 5.

[0052] A recess 620 is formed in the rear end 62 of the pressing member 6, recessed inward from the second end 1b side toward the first end 1a side. The recess 620 is a space defined by a curved surface 6200 that is convex toward the first end 1a side, and the first end 1a side is closed. In the initial state, the recess 620 receives the tip of the destructible portion 50 of the tank 5, which will be described later. The recess 620 is configured to receive most of the gas released from the tank 5, thereby obtaining a driving force to press the plunger 8.

[0053] Meanwhile, a recess 610 recessed inward from the first end 1a side toward the second end 1b side is formed in the tip 61, which is the end on the first end 1a side of the pressing member 6. The recess 610 is a substantially truncated cone-shaped space whose diameter decreases from the first end 1a side toward the second end 1b side, and the second end 1b side is closed by a circular surface 6100. The recess 610 is configured to receive the rear end 801 of the plunger 8. The recess 610 is configured to come into contact with the rear end 801 of the plunger 8 at the surface 6100 when the pressing member 6 obtains the driving force by the gas, and to press the plunger 8 toward the first end 1a side.

[0054] The material for forming the pressing member 6 is not particularly limited, but is preferably, for example, a resin, more preferably a resin that slides easily against other members and has relatively high viscosity, such as polyethylene and polypropylene.

[0055] [tank] 8 is a cross-sectional view of the tank 5. The tank 5 has a container body 53 that opens to the second end 1b side, and a lid body 54 attached to a peripheral portion 520 that defines the opening. The tank 5 is housed in the housing space S3 such that the lid body 54 faces the second end 1b side of the needle-free syringe 1, and the bottom surface portion 51 of the container body 53 faces the first end 1a side. However, the destructible portion 50, which will be described later, protrudes from the housing space S3 into the second space S2.

[0056] The container body 53 has a side wall portion 52 including a peripheral portion 520, and a bottom surface portion 51 closing the side wall portion 52 on the first end portion 1a side. The side wall portion 52 is a substantially cylindrical portion facing the inner peripheral surface of the housing space S3. The bottom surface portion 51 is a substantially disk-shaped portion continuing with the side wall portion 52 on the first end portion 1a side. The outer diameter of the bottom surface portion 51 is larger than the inner diameter of the second space S2. Therefore, the container body 53 is restricted from moving into the second space S2. The container body 53 defines a tank space S5. The tank space S5 contains a substance that serves as a drive source for driving the pressing member 6 and the plunger 8.

[0057] The amount of the substance contained in the tank space S5 is determined in advance so that the substance becomes a gas within a predetermined pressure range in the second space S2 in the temperature environment in which the needle-free syringe 1 is used, in order to provide a sufficient driving force to the pressing member 6 and the plunger 8. The type of the gas is not particularly limited, but in this embodiment, it is carbon dioxide.

[0058] The bottom surface portion 51 has a thin-walled portion 510 formed in the center of a substantially circular shape. The thin-walled portion 510 is formed so that the thickness in a cross-sectional view becomes thinner from the periphery toward the center of the bottom surface portion 51. As a result, the tank space S5 is defined so that the cross-sectional area rapidly decreases on the first end portion 1a side.

[0059] A destructible portion 50 is formed on the outer surface of the bottom portion 51 at a position corresponding to the thin portion 510. The destructible portion 50 is continuous with the thin portion 510 and has a generally cylindrical outer shape that protrudes in the direction of the axis A1 with the thin portion 510 as a base end. The destructible portion 50 is configured to break with the thin portion 510 as a base end when pressed downward in FIG. 1 by the insertion portion 21 of the trigger member 2 described later. When the destructible portion 50 breaks, at least a part of the thin portion 510 that is the base end is also removed from the tank 5, and a through hole is formed in the bottom portion 51 that penetrates it. When at least a part of the tank 5 is broken in this way, the gas in the tank space S5 flows out into the second space S2 through the through hole.

[0060] The lid body 54 is attached to the peripheral portion 520 and closes the tank space S5 from the second end 1b side, thereby maintaining the tank space S5 in a sealed state. That is, the lid body 54 closes the tank space S5 to such an extent that the amount of substance leaking from the tank space S5 does not adversely affect the operation of the needleless syringe 1. The lid body 54 may be attached to the peripheral portion 520 in any manner as long as the sealed state can be maintained. For example, the lid body 54 may be configured to be attached to the peripheral portion 520 by being fitted or screwed into the peripheral portion 520. Furthermore, the lid body 54 may be ultrasonically welded to the peripheral portion 520. In addition to or instead of this, the lid body 54 may be attached to the peripheral portion 520 via an adhesive, and a gasket or the like for sealing the gap between the lid body 54 and the peripheral portion 520 may be provided between them. Furthermore, the lid body 54 may be configured to be attached to the peripheral portion 520 by being fitted or screwed into the peripheral portion 520.

[0061] The material for forming the container body 53 and the lid 54 is not particularly limited, but is preferably, for example, a resin, and more preferably, a resin that has the strength to withstand the internal pressure in the tank 5, can be ultrasonically welded, and is easy to break at the destructible portion 50. Such a resin can be appropriately selected from, for example, engineering plastics.

[0062] [Trigger member] FIG. 9 is a perspective view of the trigger member 2. The trigger member 2 is attached to the second end 1b of the needle-free syringe 1, and is a member operated by a user to perform transdermal administration of a liquid using the needle-free syringe 1. The trigger member 2 has a main body 20, and an insertion portion 21 and a support portion 22, each continuing from the main body 20. The main body 20 has an operation portion 200 on the first end 1a side. The operation portion 200 is disposed radially outward from the side wall portion 70 of the cover member 7 described later, with the axis A1 as a reference. The operation portion 200 has an outer surface 2000 that spreads in a substantially circular shape. The outer surface 2000 is a portion on which a user places a finger such as a thumb and applies a pressing force when pushing the insertion portion 21 downward in FIG. 1.

[0063] A substantially rectangular through hole 201 is formed on the second end 1b side of the main body 20. A substantially cylindrical support 22 extending along the axis A2 is formed between a pair of walls that define the through hole 201 and face each other with respect to the axis A1. The support 22 is continuous with the pair of faces at both ends. The support 22 is received in a groove 3100 of the main body housing 3. This allows the trigger member 2 to be attached to the main body housing 3. The support 22 can rotate within the groove 3100 with respect to the axis A2. The main body 20 and the insertion portion 21 rotate around the axis A2 in conjunction with the rotation of the support 22.

[0064] The insertion portion 21 is a portion that protrudes radially inward from the surface of the main body portion 20 on the cover member 7 side with respect to the axis A1. The insertion portion 21 has a large diameter portion 210 that is continuous with the main body portion 20 and has a generally cylindrical shape with a larger diameter, and a small diameter portion 211 that is continuous with the large diameter portion 210 and has a generally cylindrical shape with a smaller diameter. When the cover member 7 described later is positioned at the first lock position, the large diameter portion 210 interferes with a first peripheral portion 7010 (see FIG. 10) of the through hole 700 of the cover member 7, thereby functioning as a stopper that restricts the pushing operation of the trigger member 2. In addition, at the first lock position, the small diameter portion 211 engages with the first peripheral portion 7010, and the relative movement with respect to the cover member 7 is restricted. Furthermore, when the cover member 7 is located at the second lock position, the large diameter portion 210 interferes with a second peripheral portion 7020 (see FIG. 10) of the through hole 700 of the cover member 7, thereby functioning as a stopper that restricts the pushing operation of the trigger member 2. In other words, when the cover member 7 is located at the first lock position and the second lock position, the tip of the small diameter portion 211 does not reach the destructible portion 50.

[0065] The small diameter portion 211 is inserted through a through hole 700 of the cover member 7 described later and a through hole 322 of the main housing 3. The tip of the small diameter portion 211 is located near the middle of the destructible portion 50 of the tank 5 and spaced apart from the outer circumferential surface of the destructible portion 50. When the cover member 7 described later is located in the release position, if a pressing force is applied to the operating portion 200, the tip of the small diameter portion 211 reaches the destructible portion 50 and breaks the destructible portion 50.

[0066] The material from which the trigger member 2 is formed is not particularly limited, but is preferably, for example, a resin, and among these, resins having relatively high strength such as engineering plastics, acrylic resins, polypropylene, polystyrene, and the like are preferable.

[0067] [Cover material] FIG. 10 is an external perspective view of the cover member 7. The cover member 7 is a member that covers at least a part of the main body housing 3 from the radial outside with respect to the axis A1. The cover member 7 has a substantially cylindrical side wall portion 70. The side wall portion 70 is open at both the first end 1a side and the second end 1b side, and extends along the axis A1 direction so as to reach at least the through hole 325 of the main body housing 3 to the through hole 322 when the cover member 7 is located at the release position described below. In particular, the side wall portion 70 is configured to face at least the through hole 325 when the cover member 7 is located at the release position. The cover member 7 forms a sound reduction mechanism together with the main body housing 3. In addition, in this embodiment, the cover member 7 forms a lock mechanism that restricts unintended operation of the needle-free syringe 1 together with the trigger member 2 and the main body housing 3. Details of the sound reduction mechanism and the lock mechanism will be described later.

[0068] The side wall portion 70 forms an outer peripheral surface 71 facing outward with respect to the axis A1, and an inner peripheral surface 72 facing inward. The cover member 7 is attached to the main body housing 3 so that the inner peripheral surface 72 faces the outer peripheral surface (including the outer peripheral surface 324) of the main body housing 3. As a result, a space S7 is formed between the inner peripheral surface 72 and the outer peripheral surface of the main body housing 3. The interval between the inner peripheral surface 72 and the outer peripheral surface of the main body housing 3 can be set appropriately and may vary along the axis A1 direction. As described later, the cover member 7 is movable with respect to the main body housing 3, and can move between a first lock position, an unlocked position, and a second lock position between these positions.

[0069] A through hole 700 is formed in the side wall 70 at the portion on the second end 1b side. The through hole 700 is formed by a first hole 701 located closest to the first end 1a, a third hole 703 located closest to the second end 1b, and a second hole 702 continuing to both the first hole 701 and the third hole 703. Of the peripheral portions defining the through hole 700, a portion including a portion closest to the first end 1a and mainly defining the first hole 701 is referred to as a first peripheral portion 7010, a portion including a portion closest to the second end 1a and mainly defining the second hole 702 is referred to as a second peripheral portion 7020, and a portion including a portion closest to the second end 1b and mainly defining the third hole 703 is referred to as a third peripheral portion 7030. The first peripheral portion 7010 forms an engagement portion 7010a in the vicinity of the second peripheral portion 7020.

[0070] The first hole 701 and the second hole 702 are formed to a certain size so that the small diameter portion 211 of the insertion portion 21 of the trigger member 2 can be inserted therethrough, but the large diameter portion 210 cannot be inserted therethrough. The third hole 703 is formed to a certain size so that the large diameter portion 210 can be inserted therethrough. The small diameter portion 211 can move relatively within the first hole 701 to the third hole 703 in conjunction with the relative position of the cover member 7 with respect to the main body housing 3. More specifically, when the cover member 7 is located at the first lock position, the small diameter portion 211 is configured to be located within the first hole 701. At this time, the first peripheral portion 7010 engages with the small diameter portion 211 at the engagement portion 7010a, and restricts the relative movement of the small diameter portion 211 with respect to the cover member 7. When the cover member 7 moves from the first lock position to the second lock position, the engagement between the small diameter portion 211 and the engagement portion 7010a is released, and the small diameter portion 211 moves from the first hole 701 to the second hole 702. When the cover member 7 is located at the second lock position, the small diameter portion 211 is located in the second hole 702. As described above, when the cover member 7 is located at the first and second lock positions, the large diameter portion 210 interferes with the first peripheral portion 7010 and the second peripheral portion 7020, so that the rotation of the trigger member 2 is restricted and the insertion portion 21 does not reach the destruction portion 50. When the cover member 7 moves from the second lock position to the release position, the small diameter portion 211 moves from the second hole 702 to the third hole 703. When the cover member 7 is located at the release position and the small diameter portion 211 is located in the third hole 703, the lock of the trigger member 2 is released. In this state, large diameter portion 210 and third peripheral portion 7030 do not interfere with each other, and large diameter portion 210 can be inserted into third hole 703. In other words, insertion portion 21 can destroy destroyed portion 50 by applying an external force that pushes insertion portion 21 deeper into second space S2.

[0071] FIG. 11 is a view of the vicinity of the through hole 700 of the side wall portion 70 as viewed from the inner circumferential surface 72 side. As shown in FIG. 11, the inner circumferential surface 72 is formed with recesses 720 and 721, as well as recesses 722 and 723, which are recessed radially outward with respect to the axis A1. The recesses 720 and 721 are each formed so as to extend from the first peripheral portion 7010 along the axis A1 direction. The recesses 722 and 723 are each formed so as to extend from the third peripheral portion 7030 along the axis A1 direction. In the inner circumferential surface 72, a portion between the recesses 721 and 723 is referred to as a surface 724, and a portion between the recesses 720 and 722 is referred to as a surface 725.

[0072] Referring again to FIG. 10, a groove portion 726 is formed in the portion of the side wall portion 70 on the side of the first end portion 1a, which is recessed radially outward with respect to the axis A1. The groove portion 726 extends along the axis A1 direction, and in this embodiment, two groove portions 726 are formed at positions 180° apart in the circumferential direction with respect to the axis A1 so as to correspond to the positions of the ribs 302 of the main body housing 3. However, the groove portion 726 may be formed as one, or as three or more, in correspondence with the configuration of the ribs 302. The ribs 302 are fitted into the groove portion 726 at the corresponding positions, and can slide along the axis A1 direction within the groove portion 726. The groove portion 726 is configured so that the ribs 302 can enter and exit the groove portion 726 with the above-mentioned sliding movement.

[0073] At the first lock position, the rib 302 is entirely fitted in the groove 726, and rotation of the cover member 7 relative to the main body housing 3 is restricted. At the second lock position, the cover member 7 moves toward the first end 1a (cylinder 10 side) relative to the main body housing 3, and the end of the rib 302 on the first end 1a side is positioned at the end of the groove 726 on the second end 1b side. That is, at the second lock position, the restriction on rotation of the cover member 7 relative to the main body housing 3 is released. At the release position, the rib 302 and the groove 726 are positioned at different circumferential positions relative to the axis A1.

[0074] The material forming the cover member 7 is not particularly limited, and can be appropriately selected from resin, metal, and the like.

[0075] [Sound reduction mechanism] As described above, in the needleless syringe 1, when the cover member 7 is located in the release position, the destructible portion 50 of the tank 5 is destroyed by the operation of the trigger member 2, and the substance in the tank space S5, which has a higher pressure, is discharged as gas into the second space S2, which has a lower pressure. The gas discharged into the second space S2 is discharged vigorously outside the second space S2 through the through hole 325 after driving the pressing member 6 and the plunger 8, and the force of this discharge generates a discharge sound. However, the side wall portion 70 of the cover member 7 is present at least in the vicinity of the through hole 325 of the main body housing 3, and further, the gas is guided into the space S7, and the force of the gas flow is reduced, so that the discharge sound when the gas flows out from the through hole 325 can be reduced. As described above, the main body housing 3 and the cover member 7 constitute a sound reduction mechanism that reduces the transmission of sound generated due to the gas that drives the pressing member 6 and the plunger 8.

[0076] [Locking mechanism] FIG. 12 is an external perspective view of the needleless syringe 1 when the cover member 7 is located at the first lock position (i), the second lock position (ii), or the release position (iii). FIG. 13 is a cross-sectional view showing the state near the trigger member 2 when the cover member 7 moves to the first lock position (i), the second lock position (ii), or the release position (iii). As shown in FIG. 12 and FIG. 13, in the first lock position (i), the small diameter portion 211 is located in the first hole 701 and engages with the engagement portion 7010a. This restricts the rotation and sliding of the cover member 7 relative to the main body housing 3. In addition, the large diameter portion 210 and the first peripheral portion 7010 interfere with each other. Furthermore, the end portion on the second end portion 1b side of the cover member 7 is located near the support portion 22 of the trigger member 2, and resists the pushing force of the trigger member 2. In addition, in the first lock position (i), the ribs 302 and the corresponding grooves 726 engage with each other, which also restricts the rotation of the cover member 7 relative to the main housing 3.

[0077] When the cover member 7 is slid in the direction of the arrow A3 in FIG. 13 relative to the main body housing 3 while the cover member 7 is in the first lock position (i), the cover member 7 moves to the second lock position (ii). As shown in FIG. 12 and FIG. 13, in the second lock position (ii), the small diameter portion 211 is located in the second hole 702, and the large diameter portion 210 and the second peripheral edge portion 7020 interfere with each other. The protrusion 320 of the main body housing 3 is fitted into the recess 720 of the cover member 7, and the protrusion 321 is fitted into the recess 721. This restricts the rotation of the cover member 7 relative to the main body housing 3. In addition, in the second lock position (ii), each rib 302 and the corresponding groove portion 726 are positioned at the same rotation angle around the axis A1.

[0078] When the cover member 7 is rotated in the direction of the arrow A4 in FIG. 13 relative to the main body housing 3 while the cover member 7 is located at the second lock position (ii), the cover member 7 moves to the release position (iii) via the state (ii') in FIG. 13. In the state (ii'), the small diameter portion 211 of the trigger member 2 is located in the second hole 702 of the cover member 7. Then, the protrusion 320 of the main body housing 3 contacts the surface 724 of the cover member 7, and the protrusion 321 contacts the surface 725. The protrusion 320 and the protrusion 321 can slide on the surface 724 and the surface 725, respectively, while the cover member 7 rotates relative to the main body housing 3. The needle-free syringe 1 of this embodiment is configured to reach the release position (iii) when the cover member 7 rotates 40° in the direction of the arrow A4 from the second lock position (ii) relative to the main body housing 3.

[0079] 12 and 13, in the release position (iii), the small diameter portion 211 of the trigger member 2 is located inside the third hole 703, and the large diameter portion 210 can be inserted into the third hole 703. The protrusion 320 of the main body housing 3 is fitted into the recess 722 of the cover member 7, and the protrusion 321 is fitted into the recess 723. In addition, in the release position (iii), the ribs 302 are not fitted into the corresponding grooves 726, and are positioned at rotation angles offset from each other around the axis A1. As described above, in this embodiment, the rotation angles are configured to be 40°.

[0080] The above description is an example in which the cover member 7 moves in this order among the first lock position (i), the second lock position (ii), and the release position (iii). However, the cover member 7 can also move in this order among the release position (iii), the second lock position (ii), and the first lock position (i) before the trigger member 2 is operated. That is, before the trigger member 2 is operated, the cover member 7 can reversibly move between the first lock position (i) and the second lock position (ii), and between the second lock position (ii) and the release position (iii). More specifically, when the cover member 7 is rotated 40° in the direction of the arrow A5 in FIG. 13 relative to the main body housing 3 while the cover member 7 is located at the release position (iii), the cover member 7 moves to the second lock position (ii). Furthermore, when the cover member 7 is slid relative to the main housing 3 in the direction opposite to the arrow A3 in FIG. 13 while the cover member 7 is in the second lock position (ii), the cover member 7 moves to the first lock position (i).

[0081] The above-described locking mechanism prevents the trigger member 2 from being operated at an unintended timing, which would result in the tank 5 being destroyed and the liquid in the first space S1 leaking out from the delivery hole 100. Note that in both the first lock position and the second lock position, the operation of the trigger member 2 is restricted. Therefore, both the first lock position and the second lock position are examples of the "lock position" of the present invention.

[0082] <2. Vial adapter configuration> An example of the configuration of the vial adapter 11 for introducing liquid into the first space S1 of the needle-free syringe 1 will be described below. The vial adapter 11 is attached to the upper opening of a vial (not shown) containing liquid, and is used for the purpose of transferring the liquid into the first space S1 of the needle-free syringe 1. FIG. 14 is a cross-sectional view showing a state in which the vial adapter 11 is connected to the connected portion 1020 of the cylinder 10. The vial adapter 11 includes a base portion 110 connected to the tip portion of the cylinder 10, a side wall portion 112 extending from the center of the base portion 110, and a pair of holding portions 111 continuing from the side wall portion 112.

[0083] The base 110 has a substantially cylindrical outer shape and is configured to cover the tip of the cylinder 10 from the radial outside. A connecting portion 1100 is formed on the inner wall surface of the base 110. The connecting portion 1100 is configured to be connectable to the connected portion 1020 of the cylinder 10. In this embodiment, the connecting portion 1100 is formed as a thread that can be screwed into the connected portion 1020. The connecting portion 1100 and the connected portion 1020 are connected by inserting the tip of the cylinder 10 into the base 110 and rotating the cylinder 10 in one direction. The inner wall surface of the base 110 has a shape that fits the outer shape of the delivery hole portion 101 of the cylinder 10 at one end of the base 110, and positions the delivery hole portion 101 within the space of the base 110 when the base 110 is connected to the cylinder 10. When the delivery hole portion 101 is positioned within the space of the base portion 110, the delivery hole 100 and a flow path 1121, which will be described later, are in a communication state.

[0084] The side wall portion 112 has an inner wall surface 1120 that is continuous with the inner wall surface of the base portion 110. The inner wall surface 1120 defines a flow path 1121. The flow path 1121 is a liquid passage for the needleless syringe 1 to draw liquid from the vial through the delivery hole 100. The side wall portion 112 has an opening 1122 formed near the tip portion, and the liquid in the vial can flow into the flow path 1121 through the opening 1122. The side wall portion 112 further has a needle-shaped puncture portion 1123 at the tip portion. The puncture portion 1123 punctures the lid of the vial, allowing the side wall portion 112 to access the liquid contained in the vial.

[0085] The pair of holding parts 111 are formed at positions 180° apart from each other so as to extend radially outward from the side wall part 112. The pair of holding parts 111 are preferably elastically deformable and configured to hold the side wall of the vial from both sides. This prevents the vial from tilting or falling over during the operation of sucking the liquid in the vial with the needle-free syringe 1. Note that the configuration of the vial adapter 11 described above is an example, and the configuration of the vial adapter 11 can be changed as appropriate. In addition, for example, a syringe kit including at least the needle-free syringe 1 and the vial adapter 11 may be configured by combining the needle-free syringe 1 with the vial adapter 11 that can be connected thereto.

[0086] <3. Manufacturing method and method of using needleless syringe> An example of a method for producing (manufacturing) and using the needle-free syringe 1 will now be described.

[0087] First, a syringe unit for producing the needleless syringe 1 is prepared. The syringe unit is a component that includes at least a trigger member 2, a main housing 3, a lid 4, a tank 5, and a pressing member 6, and is assembled as shown in FIG. 1. That is, in the syringe unit, the support 22 of the trigger member 2 is rotatably connected to the protruding portion 310 of the main housing 3, the cover member 7 covers the main housing 3 from the outside, and the insertion portion 21 of the trigger member 2 is inserted into the through hole 700 and the through hole 322. In addition, in the syringe unit, the tank 5 in which a predetermined substance is sealed is accommodated in the housing space S3, the pressing member 6 is accommodated in the second space S2 so as to be in an initial state, and the lid 4 is attached to the rear end portion 31. In the syringe unit, it is preferable that the cover member 7 is located at the first lock position so that the tank 5 is not destroyed by erroneous operation of the trigger member 2. In addition, in the syringe unit, it is preferable that the temperature of the environment in which the tank 5 is stored is controlled within a certain range in order to control the internal pressure of the tank 5.

[0088] Furthermore, before or after the preparation of the syringe unit, or in parallel therewith, a cylinder unit is prepared. The cylinder unit includes at least a plunger 8 and a cylinder 10.

[0089] Next, the plunger 8 of the cylinder unit is pushed into the end of the first end 1a side of the cylindrical space S11. Before or after or in parallel with the pushing of the plunger 8, the vial adapter 11 is connected to the tip of the cylinder 10, resulting in the state shown in FIG.

[0090] Next, a vial containing a liquid is prepared. The vial containing a liquid is preferably stored in a temperature environment controlled within a predetermined range, and is taken out from the storage location immediately before use. The vial containing a liquid can be stored separately from the syringe unit and the cylinder unit.

[0091] Next, the lid of the vial is pierced by the piercing portion 1123 of the vial adapter 11 connected to the cylinder unit, while the side wall of the vial is sandwiched and held by the pair of holding portions 111.

[0092] Next, it is confirmed that the opening 1122 of the vial adapter 11 is immersed in the liquid in the vial, and the plunger 8 is retracted toward the base 103 of the cylinder 10. This causes the liquid in the vial to flow into the first space S1. When a predetermined amount of liquid is contained in the first space S1, the vial adapter 11 is removed from the cylinder 10. This provides a cylinder unit filled with liquid.

[0093] Next, the cylinder unit containing the liquid is connected to the syringe unit. More specifically, the plunger 8 is accommodated in the second space S2 of the main body housing 3 from the tip portion 30 side, and the connection portion 104 of the cylinder 10 is screwed to the tip portion 30 of the main body housing 3. This provides the needleless syringe 1 in a state in which the liquid is contained in the first space S1. It is noted that either the removal of the vial adapter 11 from the cylinder 10 or the connection of the cylinder unit containing the liquid to the syringe unit may be performed first.

[0094] Next, the needle-free syringe 1 is unlocked. Specifically, the cover member 7 located at the first lock position is slid toward the first end portion 1a with respect to the main body housing 3. By this operation, the cover member 7 moves to the second lock position.

[0095] Next, the cover member 7, which is located in the second lock position, is rotated relative to the main body housing 3 and moved to the release position. This causes the needle-free syringe 1 to be completely unlocked.

[0096] Next, the needle-free syringe 1 is positioned relative to the living body. Specifically, the delivery hole portion 101 is placed against the skin surface of the living body, and an appropriate force is applied so that no gap is formed between the periphery of the delivery hole 100 and the skin surface of the living body. At this time, it is preferable that the needle-free syringe 1 is fixed so as to be perpendicular to the skin surface of the living body.

[0097] Next, the operating portion 200 of the trigger member 2 is pushed toward the cover member 7, and the breakable portion 50 of the tank 5 is broken by the insertion portion 21. As a result, a through hole is formed in the bottom surface portion 51 of the tank 5, and the substance in the tank space S5 flows out as high-pressure gas into the second space S2 through the through hole. The outflowing gas releases the pressing member 6 from the engagement between the rib 600 and the rib 3260 of the main body housing 3, applies pressure to the pressing member 6, and moves the pressing member 6 and the plunger 8 toward the first end portion 1a. The plunger 8, while having its rear end portion 801 pressed by the pressing member 6, pushes the liquid in the second space S2 to the delivery hole 100 by the gasket 9. The liquid pushed out from the delivery hole 100 penetrates the outermost layer of the skin of the living body due to the pressure, and reaches at least one of the skin tissue, subcutaneous tissue, and fascia. In this manner, the pressing member 6 and the plunger 8 are driven, and transdermal administration is performed.

[0098] In the needle-free syringe 1 according to this embodiment, when the gas released from one tank 5 causes the tapered portion 91 of the gasket 9 to enter the tapered space S10 (see FIG. 15), one transdermal administration is completed.

[0099] The gas that has driven the pressing member 6 and the plunger 8 flows into the space S7 through the through hole 325 of the main housing 3, and then diffuses outside the cover member 7. When the gas passes through the through hole 325, a discharge sound such as "psh" may be generated, but since the cover member 7 is interposed between the second space S2 and the external space of the needle-free syringe 1, the sound is unlikely to be transmitted to the ears of humans or animals. Furthermore, by forming the space S7, the momentum of the gas that has flowed out from the through hole 325 can be weakened within the space S7. This makes it possible to suppress the volume of the discharge sound itself.

[0100] <4. Features> According to the needle-free syringe 1 of the above embodiment, the cover member 7 reduces the sound generated by the gas that drives the pressing member 6 and the plunger 8, making it difficult to startle a person or animal that is the subject of transdermal administration. This makes it possible to avoid a situation in which the person or animal makes an unexpected movement during transdermal administration and the transdermal administration is not performed properly.

[0101] Furthermore, in the needle-free syringe 1 according to the above embodiment, the cylinder 10 is configured to be detachable from the main body housing 3. For this reason, for example, the syringe unit and a cylinder unit containing a liquid prepared in advance can be managed separately, and assembled into the needle-free syringe 1 immediately before use. This is particularly useful in cases where the liquid to be administered transdermally requires relatively strict temperature control, or when multiple needle-free syringes 1 are used to administer transdermally to a group of people, etc.

[0102] Furthermore, the syringe unit of the needle-free syringe 1 according to the above embodiment is configured to be non-reusable, and the cylinder unit is configured to be disposable, thereby ensuring hygiene and extremely reducing the risk of infectious diseases.

[0103] Furthermore, in the needle-free syringe 1 according to the above embodiment, the cover member 7 is configured to be movable between a locked position and an unlocked position. This prevents the trigger member 2 from being unintentionally operated, destroying the tank 5 and resulting in the waste of the liquid in the first space S1, and ensures that transdermal administration can be performed reliably.

[0104] <5. Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the following modifications are possible. In addition, the gist of the following modifications can be combined as appropriate.

[0105] (1) The needle-free syringe 1 does not have to be separated into a syringe unit and a cylinder unit. That is, the main body housing 3 and the cylinder 10 may be integrally configured and inseparable. The vial adapter 11, the syringe kit, the syringe unit, and the cylinder unit described in the above embodiments are also included in the scope of the present invention.

[0106] (2) The locking mechanism between the cover member 7 and the main housing 3 may be omitted. In addition, the locking position of the cover member 7 does not have to have two stages, the first locking position and the second locking position, but may have one stage or three or more stages.

[0107] (3) At least one of the shapes of the trigger member 2, the main housing 3, the lid 4, the tank 5, the pressing member 6, the cover member 7, the plunger 8, and the cylinder 10 may be modified at least in part.

[0108] (4) The connection mechanism between the main body housing 3 and the cylinder 10 is not limited to that in the above embodiment. For example, the cylinder 10 and the main body housing 3 may be configured such that the tip portion 30 of the main body housing 3 is inserted into the connection portion 104 of the cylinder 10.

[0109] (5) The needleless syringe 1 may further include a filler filled in the space S7. FIGS. 16A-C are diagrams showing configuration examples of such fillers 77A-77C. The fillers 77A-77C are members filled between the outer peripheral surface of the main housing 3 and the inner peripheral surface of the cover member 7 over the entire circumference, and can ensure the effect of the sound reduction mechanism. FIGS. 16A-C are diagrams showing a part of the fillers 77A-77C as viewed from the outer peripheral surface side of the main housing 3. As shown in FIG. 16A, the filler 77A has an inner peripheral surface 770A on which a plurality of ribs 7701 extending in the circumferential direction are formed alternately along the axis A1 direction. As shown in FIG. 16B, the filler 77B has an inner peripheral surface 770B on which a spiral rib 7703 is formed.

[0110] As shown in FIG. 16C, a side wall portion 770C of another filler 77C has a plurality of regularly arranged circular through-holes 7704 (only representative ones are labeled with reference numerals in the drawing).

[0111] The material constituting such a filler is not particularly limited, but examples thereof include urethane foam, polypropylene, polyethylene, polylactic acid, etc. The shape of the filler is also not limited to the curved plate-like shape as described above, and may be, for example, cotton-like.

[0112] (6) Fig. 17A is a cross-sectional view of a needle-free syringe 1D equipped with a cover member 7D according to a modified example, and the configuration other than the cover member 7D is the same as that of the needle-free syringe 1. As shown in Fig. 17A, in the needle-free syringe 1D, the space S7 between the inner peripheral surface 72D of the cover member 7D and the outer peripheral surface 324 of the main body housing 3 is narrower than that of the needle-free syringe 1 according to the above embodiment. According to the inventor's study, even if the space S7 is narrower in this way, the cover member 7D and the main body housing 3 can form a sound reduction mechanism similar to that of the above embodiment. For reference, an external perspective view of the needle-free syringe 1D is shown in Fig. 17B. EXAMPLES

[0113] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0114] <Experiment> Five types of needle-free syringes according to Examples 1 to 5 and one type of needle-free syringe according to Comparative Example were prepared, each in five pieces. The needle-free syringe according to Example 1 was similar to the needle-free syringe according to the above embodiment, and had the configuration shown in FIG. 1. The needle-free syringes according to Examples 2 to 4 had the same configuration and dimensions as the needle-free syringe according to Example 1, and had a filler filled between the inner circumferential surface of the cover member and the outer circumferential surface of the main body housing. More specifically, the needle-free syringe according to Example 2 had a filler as shown in FIG. 16A, the needle-free syringe according to Example 3 had a filler as shown in FIG. 16B, and the needle-free syringe according to Example 4 had a filler as shown in FIG. 16C. All of the fillers were made of polylactic acid, and were arranged so as to surround the entire outer circumferential surface of the main body housing. In addition, the needle-free syringe according to Example 5 was configured so that the space between the main body housing was narrower than that of the needle-free syringe according to Example 1, as shown in FIG. 17A. The needle-free syringe according to the comparative example had the same configuration and dimensions as the needle-free syringe according to the example 1, except that it did not have a cover member.

[0115] In the needleless syringes according to Examples 1 to 5 and Comparative Example, the trigger member was operated without containing liquid in the cylinder, and the sound level when each tank was destroyed was measured using a sound level meter (LA-7500, manufactured by Ono Sokki Co., Ltd.) and the sound levels were compared over time. The measurement conditions were as follows. The sound level meter was fixed at a location 50 cm away from each needleless syringe. [Measurement conditions] Level range: 50-120dB Time weighting characteristics: Fast Frequency weighting: Z characteristic

[0116] <Experimental Results> When the needle-free syringes according to Examples 1 to 5 and Comparative Example (five each) were operated, the graphs of the sound level measured by the sound level meter over time were as shown in Figs. 18A to 18F, respectively. In the graphs, the horizontal axis represents time [seconds], and the vertical axis represents sound level [dB]. In the graphs of Figs. 18A to 18F, the peaks (areas enclosed by dashed lines) in the vicinity of 0.05 to 0.1 seconds indicate the sound level of the sound generated by the sudden outflow of gas due to the destruction of the tank. There was no significant difference in the peaks of the sound level caused by the sudden outflow from the tank between the needle-free syringes according to Examples 1 to 5 and Comparative Example. However, after the destruction of the tank, an even larger peak of the sound level caused by the discharge of gas from the main body housing was observed in the needle-free syringe according to Comparative Example (area enclosed by solid lines in Fig. 18F). In contrast, in the needle-free syringes according to Examples 1 to 5, the peaks in the sound levels caused by the gas being discharged through the through-holes in the main housing were barely observed (FIGS. 18D and E), or were clearly smaller than the peaks in the sound levels caused by the gas flowing out of the tank (areas enclosed by solid lines in FIGS. 18A to C).These results confirmed the effectiveness of the sound reduction mechanism of the needle-free syringe according to the present invention. [Explanation of symbols]

[0117] 1 Needleless syringe 1a 1st end 1b Second end 2 Trigger member 3 Main housing 5. Tank 6 Pressing member 7 Cover material 8 Plunger 9 Gasket 10 Cylinders 21 Insertion part 30 Tip (connected part) 50 Destroyed part 70 Side wall 100 outlet hole 104 Connection 325 Through hole S1 1st space S2 2nd space S7 space

Claims

1. A needleless syringe having a first end portion having a delivery hole for transdermally administering a liquid to a living body, and a second end portion opposite the first end portion, a cylinder in which the delivery hole is formed and which defines a first space for containing the liquid; a cylindrical main body housing connected to the cylinder at the second end side of the cylinder and defining a second space communicating with the first space; a plunger movable within the first space and the second space; a pressing member that is movable within the second space and presses the plunger from the second end side; a tank disposed on the second end side of the pressing member in the second space and configured to seal a substance; a trigger member capable of breaking at least a part of the tank so as to release the substance as a gas into the second space to drive the pressing member; a cylindrical cover member that covers at least a portion of the main body housing from the outside; Equipped with the cover member and the main housing form a sound reduction mechanism that reduces sound generated by the gas when the gas is released into the second space. Needleless syringe.

2. a through hole is formed in the main body housing to communicate the second space with an external space of the main body housing; The cover member has a side wall portion facing the through hole. The needle-free syringe of claim 1.

3. The trigger member is configured to be actuated by application of an external force from outside the cover member and to be capable of destroying at least a portion of the tank, The cover member is configured to be movable between a lock position that restricts the operation of the trigger member and a release position that releases the restriction on the operation of the trigger member. The needleless syringe according to claim 1 or 2.

4. the trigger member has an insertion portion that passes through the cover member and the main housing and is disposed in the second space, When the cover member is located at the lock position, the insertion portion does not reach the tank, When the cover member is located at the release position, the insertion portion reaches the tank due to an external force applied to the trigger member. The needleless syringe according to claim 3.

5. the side wall portion has an inner circumferential surface that faces an outer circumferential surface of the main housing and forms a space between the inner circumferential surface and the outer circumferential surface, Further comprising a filler material filled in the space. The needleless syringe according to claim 2.

6. The cylinder is configured to be detachable from the main body housing. The needleless syringe according to claim 1 or 2.

7. The gas is carbon dioxide. The needleless syringe according to claim 1 or 2.

8. The needleless syringe according to claim 1 or 2, a vial adapter connectable to the first end of the needleless syringe; Equipped with Syringe kit.

9. A syringe unit for constituting a needleless syringe having a first end portion in which a delivery hole for transdermally administering a liquid to a living body is formed, and a second end portion opposite to the first end portion, a cylindrical main body housing, the main body housing being connected to the second end side of a cylinder in which the delivery hole is formed and which defines a first space for containing the liquid, the main body housing defining a second space communicating with the first space, the main body housing being capable of accommodating a plunger which moves within the first space and the second space; a pressing member that is movable within the second space and presses the plunger from the second end side; a tank disposed on the second end side of the pressing member in the second space and configured to seal a substance; a trigger member capable of breaking at least a part of the tank so as to release the substance as a gas into the second space to drive the pressing member; a cylindrical cover member that covers at least a portion of the main body housing from the outside; Equipped with the cover member and the main housing form a sound reduction mechanism that reduces sound generated by the gas when the gas is released into the second space. Syringe unit.

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