Injection needle, injection needle assembly, and syringe

Abstract

An injection needle according to the present disclosure comprises a tubular body part that extends from a base end to a needle tip. The body part is provided with: a front-side bevel face that extends to the needle tip; a first back surface part and a second back surface part that are planar and are formed on the back side of the front-side bevel face; and a back-side bevel face that includes a first back-side bevel face part and a second back-side bevel face part positioned on the back side of the front-side bevel face. The first back surface part and the second back surface part extend substantially parallel to the longitudinal direction of the body part or extend inclined relative to the longitudinal direction in a state of approaching each other toward the needle tip. The first back-side bevel face part and the second back-side bevel face part form a ridge part extending to the needle tip at a position where the first back-side bevel face part and the second back-side bevel face part intersect with each other. The outer diameter of the body part is 0.15-0.26 mm, and the bevel face length is 0.15-0.5 mm.

Description

Injection needle, injection needle assembly, and syringe

[0001] The present disclosure relates to an injection needle, an injection needle assembly, and a syringe.

[0002] A chemical solution such as a biopharmaceutical like an influenza vaccine is usually administered subcutaneously into the subcutaneous tissue of the skin or intramuscularly into the deeper muscle tissue. However, it has been found that the vaccine dosage can be reduced by administering the vaccine targeting the upper skin layers such as the epidermis and dermis where many immune cells are present. Patent Document 1 discloses an injection needle assembly capable of injecting a chemical solution into the upper skin layer.

[0003] Japanese Patent No. 6625566

[0004] According to the injection needle assembly described in Patent Document 1, even with a short blade surface length, the puncture resistance to the skin can be reduced, but there is still room for improvement from the viewpoint of reducing the puncture resistance to the skin.

[0005] An object of the present disclosure is to provide an injection needle, an injection needle assembly, and a syringe having a shape capable of reducing the puncture resistance to the skin even with a short blade surface length.

[0006] An injection needle in a first aspect of the present disclosure comprises: (1) a tubular body portion extending from the base to the tip of the needle, the body portion including a front inclined cutting surface portion extending inclined with respect to the longitudinal direction of the body portion, the front cutting surface extending to the tip of the needle, a planar first back surface portion and a second back surface portion formed on the back side of the front cutting surface at different positions in the circumferential direction of the body portion, and a back cutting surface portion including a first back cutting surface portion located on the back side of the front cutting surface, connected to the tip of the needle in the longitudinal direction with respect to the first back surface portion and forming a first cutting edge that extends to the tip of the needle at a position intersecting the front cutting surface, and a second back cutting surface portion connected to the tip of the needle in the longitudinal direction with respect to the second back surface portion and forming a second cutting edge that extends to the tip of the needle at a position intersecting the front cutting surface, The first and second back surfaces extend substantially parallel to the longitudinal direction, or extend inclined with respect to the longitudinal direction so as they approach the needle tip; the first and second back surface portions of the back blade surface form a ridge portion at the position where they intersect, extending to the needle tip; the outer diameter of the main body is 0.15 mm or more and 0.26 mm or less; and the blade surface length, which is the maximum length in the longitudinal direction of the front and back blade surfaces, is 0.15 mm or more and 0.5 mm or less.

[0007] An injection needle as one embodiment of the present disclosure is the injection needle described in (1) above, wherein the angle of each of the first cutting edge and the second cutting edge in a cross-sectional view perpendicular to the longitudinal direction is less than 90 degrees.

[0008] An injection needle as one embodiment of the present disclosure is the injection needle according to (1) or (2) above, wherein the first back cutting surface portion and the second back cutting surface portion have a length of 50% or more of the cutting surface length in the longitudinal direction.

[0009] An injection needle as one embodiment of the present disclosure is the injection needle according to any one of (1) to (3) above, wherein, in a top view of the main body portion viewed from the side of the front cutting surface, the angle formed by the first cutting edge and the second cutting edge is 90 degrees or less.

[0010] An injection needle as one embodiment of the present disclosure is the injection needle described in (4) above, wherein the front cutting surface is connected to the front inclined cutting surface portion and extends to the needle tip, and has a front cutting edge cutting surface portion whose angle of inclination with respect to the longitudinal direction is smaller than that of the front inclined cutting surface portion, and in a top view of the main body portion as seen from the side of the front cutting surface, the angle formed by the first cutting edge and the second cutting edge is smaller at the position of the front cutting edge cutting surface portion than at the position of the front inclined cutting surface portion.

[0011] An injection needle as one embodiment of the present disclosure is the injection needle according to any one of (1) to (5) above, wherein in a side view of the main body, the angle formed by the front cutting surface and the back cutting surface at the position of the needle tip is 45 degrees or less.

[0012] An injection needle as one embodiment of the present disclosure is the injection needle according to any one of (1) to (6) above, wherein in a side view of the main body, the inclination angle of the front inclined cutting edge portion with respect to the longitudinal direction is 45 degrees or less.

[0013] An injection needle as one embodiment of the present disclosure is an injection needle according to any one of (1) to (7) above, wherein the main body portion has an outer peripheral surface whose outer shape is substantially circular in a cross-sectional view perpendicular to the longitudinal direction, and includes a needle base portion located on the base end side of the main body portion from the front cutting surface in the longitudinal direction, and the first back portion and the second back portion extend from the front cutting surface to the base end side of the main body portion in the longitudinal direction, and are connected to the outer peripheral surface of the needle base portion via a stopper surface portion facing the needle tip side in the longitudinal direction.

[0014] An injection needle as one embodiment of the present disclosure is (9) an injection needle according to any one of (1) to (7) above, wherein the main body portion has an outer peripheral surface whose outer shape is substantially circular in a cross-sectional view perpendicular to the longitudinal direction, and includes a needle base portion located on the base end side of the main body portion from the front cutting surface in the longitudinal direction, and the first back portion and the second back portion do not extend from the front cutting surface to the base end side of the main body portion in the longitudinal direction, and are connected to the outer peripheral surface of the needle base portion via an inclined surface portion that is inclined with respect to the longitudinal direction.

[0015] A second aspect of the present disclosure is an injection needle assembly comprising: (10) an injection needle as described in (8) or (9) above; and a needle holder for holding the injection needle.

[0016] A syringe in a third aspect of the present disclosure is a syringe comprising: (11) the injection needle assembly described in (10) above; and a syringe body connectable to the needle holder of the injection needle assembly.

[0017] According to this disclosure, it is possible to provide an injection needle, an injection needle assembly, and a syringe having a shape that can reduce the resistance to skin puncture even with a short cutting edge length.

[0018] This figure shows a syringe as one embodiment of the present disclosure. This is a cross-sectional view of a syringe assembly as one embodiment of the present disclosure. This is a top view of the tip of the main body of a syringe as one embodiment of the present disclosure. This is a bottom view of the tip of the main body of the syringe shown in Figure 3A. This is a side view of the tip of the main body of the syringe shown in Figure 3A. This is a cross-sectional view taken along the line I-I in Figures 3A to 3C. This is a cross-sectional view taken along the line II-II in Figures 3A to 3C. This is a cross-sectional view taken along the line III-III in Figures 3A to 3C. This is a perspective view of the tip of the main body of a syringe as another embodiment of the present disclosure. This is a top view of the tip of the main body of the syringe shown in Figure 7. This is a bottom view of the tip of the main body of the syringe shown in Figure 7. This is a side view of the tip of the main body of the syringe shown in Figure 7. This is a perspective view showing a modified example of the main body of the syringe shown in Figure 7. This is a bottom view of the tip of the main body shown in Figure 9.

[0019] Hereinafter, embodiments of the injection needle, injection needle assembly, and syringe relating to this disclosure will be described with reference to the drawings. In each figure, the same components are denoted by the same reference numerals.

[0020] Figure 1 shows a syringe 1 as one embodiment of the syringe according to the present disclosure. The syringe 1 is configured to inject a drug solution into the upper layer of the skin, which consists of the epidermal and dermal layers. Figure 1 is an exploded front view showing the syringe 1 before use. The syringe 1 comprises a syringe body 100 and a needle assembly 10 as one embodiment of the needle assembly according to the present disclosure. The syringe body 100 is configured to be detachably attached to the needle assembly 10. The syringe body 100 may be, for example, a pre-filled syringe pre-filled with a drug solution such as a vaccine. Figure 2 is a cross-sectional view of the needle assembly 10 shown in Figure 1. In Figure 2, for convenience of explanation, a cross-section of the connection portion of the syringe body 100 that can be connected to the needle assembly 10 is also shown.

[0021] As shown in Figure 1, the syringe body 100 comprises a barrel portion 180, a drug solution discharge tube portion 170, and a plunger 190. As shown in Figure 2, the barrel portion 180 has a compartment inside that can contain the drug solution 181. The drug solution discharge tube portion 170 is provided on the tip side of the barrel portion 180. The plunger 190 comprises a gasket 191 and a plunger 192. The gasket 191 is inserted into the compartment from the base end side of the barrel portion 180. The plunger 192 is connected to the base end side of the gasket 191. As shown in Figure 2, the drug solution 181 is sealed between the gasket 191 and the drug solution discharge tube portion 170 in the compartment of the barrel portion 180. The drug solution 181 is discharged from the drug solution discharge tube portion 170 when the plunger 190 is pushed toward the tip side of the barrel portion 180. The drug solution discharge tube 170 may be sealed with a cap until just before the syringe body 100 is connected to the injection needle assembly 10, so as to prevent the drug solution 181 from leaking out and from being contaminated by external bacteria.

[0022] As shown in Figure 2, the injection needle assembly 10 of this embodiment comprises an injection needle 20 as one embodiment of the injection needle according to the present disclosure, and a needle holder 80 that holds the injection needle 20. The needle holder 80 is configured to be connectable to a syringe body 100. The needle holder 80 of this embodiment comprises a needle hub 81 that holds the injection needle 20, an elastic body 82 through which the injection needle 20 is inserted, and a housing cylinder 83 that houses the needle hub 81 and the elastic body 82 inside, and has an insertion opening 83a into which the drug solution discharge tube portion 170 of the syringe body 100 can be inserted.

[0023] The injection needle 20 is held by passing through the center of the needle hub 81. As shown in Figures 1 and 2, the injection needle 20 protrudes from the tip surface 81b of the needle hub 81.

[0024] The injection needle 20 comprises a tubular body portion 20a extending from the base end 20a1 to the tip of the needle, which is the needle tip 20a2. More specifically, the injection needle 20 of this embodiment consists of a needle tube as the body portion 20a.

[0025] Hereinafter, in the injection needle 20, the longitudinal direction A of the main body 20a will be simply referred to as "longitudinal direction A". Also, in the injection needle 20, the direction around the axis with the main body 20a as the central axis will be simply referred to as "circumferential direction B". Furthermore, in the injection needle 20, the radial direction of a virtual circle with the main body 20a as the central axis in a cross-sectional view perpendicular to the longitudinal direction A of the main body 20a will be simply referred to as "radial direction C".

[0026] The main body portion 20a contains a drug solution lumen 20b that penetrates in the longitudinal direction A. The tip opening 20b1 of the drug solution lumen 20b is formed on the tip surface of the main body portion 20a. The main body portion 20a in this embodiment includes a front cutting surface 21, a first back surface 22, a second back surface 23, a back cutting surface 24, and a needle base portion 25. Details of the injection needle 20 will be described later (see Figures 3A to 6).

[0027] The needle hub 81 contains a through hole 81a through which the main body portion 20a of the injection needle 20 passes. The main body portion 20a passes through the through hole 81a of the needle hub 81, and the needle tip 20a2 side of the main body portion 20a protrudes from the tip surface 81b of the needle hub 81. In this state, the needle hub 81 holds the needle base portion 25 of the main body portion 20a. Specifically, the through hole 81a is filled with and hardened adhesive 86, and the needle base portion 25 of the main body portion 20a is bonded to the needle hub 81 by this adhesive 86.

[0028] The elastic body 82 is compressed and sandwiched between the drug discharge tube 170 of the syringe body 100 and the needle hub 81 when the drug discharge tube 170 of the syringe body 100 is inserted into the insertion opening 83a of the housing cylinder 83. This allows the drug discharge tube 170 and the injection needle 20 held by the needle hub 81 to be in liquid-tight communication.

[0029] The syringe body 100 can be connected to the needle holder 80 by inserting the drug dispensing tube portion 170 into the insertion opening 83a of the housing cylinder 83. The syringe body 100 of this embodiment is equipped with a Luer lock connector compliant with ISO 80369-7:2016. Specifically, the syringe body 100 of this embodiment includes an outer cylinder 171 surrounding the drug dispensing tube portion 170, with a female threaded portion 171a formed on its inner surface. Furthermore, the outer surface of the housing cylinder 83 of this embodiment is provided with a male threaded portion 83b that can be screwed into the female threaded portion 171a of the outer cylinder 171. However, the connection configuration of the syringe body 100 and the needle holder 80 is not limited to the connection configuration of this embodiment.

[0030] Next, we will describe the details of the injection needle 20.

[0031] Figure 3A is a magnified view of the tip of the main body 20a of the injection needle 20, which is a top view of the main body 20a. Here, the top view of the main body 20a is a plan view of the main body 20a as seen from the front side where the front cutting surface 21 is formed. Figure 3B is a magnified view of the tip of the main body 20a of the injection needle 20, which is a bottom view of the main body 20a. Here, the bottom view of the main body 20a is a plan view of the main body 20a as seen from the back side where the back cutting surface 24 is formed. Figure 3C is a magnified view of the tip of the main body 20a of the injection needle 20, which is a side view of the main body 20a. Here, the side view of the main body 20a is a plan view of the main body 20a as seen from a direction perpendicular to the longitudinal direction A, as seen from a position where the front cutting surface 21 appears linear.

[0032] As shown in Figures 3A to 3C, the main body portion 20a includes a front blade surface 21, a first back surface portion 22, a second back surface portion 23, and a back blade surface 24.

[0033] The front cutting surface 21 includes a front inclined cutting surface portion 26 that extends inclined with respect to the longitudinal direction A. More specifically, the front cutting surface 21 of this embodiment is composed of a front inclined cutting surface portion 26. The front inclined cutting surface portion 26 of this embodiment is composed of a planar inclined surface that is inclined with respect to the longitudinal direction A.

[0034] The first back surface portion 22 and the second back surface portion 23 are formed on the back side of the front cutting surface 21 at different positions in the circumferential direction B. The first back surface portion 22 and the second back surface portion 23 are both planar. In this embodiment, the first back surface portion 22 and the second back surface portion 23 extend substantially parallel to the longitudinal direction A, but the configuration is not limited to this. The first back surface portion 22 and the second back surface portion 23 may extend inclined with respect to the longitudinal direction A so that they approach each other as they move towards the needle tip 20a2.

[0035] The back blade surface 24 includes a first back blade surface portion 27 and a second back blade surface portion 28 located on the back side of the front blade surface. The first back blade surface portion 27 is connected to the first back surface portion 22 on the needle tip 20a2 side in the longitudinal direction A. The first back blade surface portion 27 also forms a first cutting edge 29a that extends to the needle tip 20a2 at a position where it intersects with the front blade surface 21. The second back blade surface portion 28 is connected to the second back surface portion 23 on the needle tip 20a2 side in the longitudinal direction A. The second back blade surface portion 28 also forms a second cutting edge 29b that extends to the needle tip 20a2 at a position where it intersects with the front blade surface 21. In other words, the first cutting edge 29a and the second cutting edge 29b are part of the outer edge of the front blade surface 21.

[0036] The first and second back cutting surface portions 27 and 28 of the back cutting surface 24 form a ridge portion 29c that extends to the needle tip 20a2 at a position where they intersect on the back side of the front cutting surface 21.

[0037] Figure 4 is a cross-sectional view of the main body 20a at the position of line I-I in Figures 3A to 3C. Figure 5 is a cross-sectional view of the main body 20a at the position of line II-II in Figures 3A to 3C. Figure 6 is a cross-sectional view of the main body 20a at the position of line III-III in Figures 3A to 3C.

[0038] As shown in Figure 4, the main body portion 20a includes an arc-shaped portion 30 whose shape in a cross-sectional view perpendicular to the longitudinal direction A is arc-shaped, and a flat plate-shaped first plate portion 31 and a second plate-shaped portion 32. In this embodiment, the arc-shaped portion 30, the first plate-shaped portion 31, and the second plate-shaped portion 32 each have a substantially uniform thickness regardless of their position in the longitudinal direction A. The arc-shaped portion 30 is located on the front side of the main body portion 20a. In this embodiment, the arc-shaped portion 30 is semicircular. The first plate-shaped portion 31 and the second plate-shaped portion 32 are located on the back side of the main body portion 20a where the back blade surface 24 is formed. In Figure 4, the first plate-shaped portion 31 is located on the right side. In Figure 4, the second plate-shaped portion 32 is located on the left side. In Figure 4, the upper end of the first plate-shaped portion 31 is continuous with the lower right end of the arc-shaped portion 30. In Figure 4, the upper end of the second plate-like portion 32 is continuous with the lower left end of the arc-shaped portion 30. In Figure 4, the lower ends of the first plate-like portion 31 and the second plate-like portion 32 are continuous. The shape of the first plate-like portion 31 and the second plate-like portion 32 in a cross-sectional view perpendicular to the longitudinal direction A (see Figure 4) is generally the shape of the letter V. Thus, the main body portion 20a has an arc-shaped portion 30 on its front side that is convex outward in the radial direction C. The main body portion 20a also has a first plate-like portion 31 and a second plate-like portion 32 on its back side that form a V-shape that is convex outward in the radial direction C. In Figures 3A to 6, the central axis of the arc-shaped portion 30 is shown as the axis O of the main body portion 20a.

[0039] As shown in Figures 5 and 6, the front cutting surface 21 is formed on the needle tip 20a2 side in the longitudinal direction A of the arc-shaped portion 30 of the main body 20a. Specifically, the front cutting surface 21 is formed to connect with the curved outer surface of the arc-shaped portion 30 of the main body 20a on the needle tip 20a2 side in the longitudinal direction A. More specifically, in this embodiment, the front inclined cutting surface portion 26 is connected with the curved outer surface of the arc-shaped portion 30 of the main body 20a on the needle tip 20a2 side in the longitudinal direction A. The front inclined cutting surface portion 26 in this embodiment extends to the needle tip 20a2. The back cutting surface 24 is formed on the needle tip 20a2 side in the longitudinal direction A of the first plate-shaped portion 31 and the second plate-shaped portion 32 of the main body 20a. More specifically, the planar outer surface of the first plate-shaped portion 31 of the main body 20a is the first back surface portion 22 described above. The first back blade portion 27 of the back blade surface 24 is formed to connect with the planar outer surface of the first plate-shaped portion 31 of the main body portion 20a on the side of the needle tip 20a2 in the longitudinal direction A. The planar outer surface of the second plate-shaped portion 32 of the main body portion 20a is the second back surface portion 23 described above. The second back blade portion 28 of the back blade surface 24 is formed to connect with the planar outer surface of the second plate-shaped portion 32 of the main body portion 20a on the side of the needle tip 20a2 in the longitudinal direction A.

[0040] Thus, in the main body portion 20a, the first back cutting surface portion 27 and the second back cutting surface portion 28 of the back cutting surface 24 are formed to be continuous with respect to the first back surface portion 22 and the second back surface portion 23 on the needle tip 20a2 side in the longitudinal direction A. Therefore, compared to a configuration in which the first back cutting surface portion 27 and the second back cutting surface portion 28 of the back cutting surface 24 are formed to be continuous with respect to the portion having the same shape as the arc-shaped portion 30 on the needle tip 20a2 side in the longitudinal direction A, it becomes easier to sharpen the area near the needle tip 20a2 of the main body portion 20a. When the main body portion 20a is manufactured, the plate portion that will become the first plate-shaped portion 31 extends from the first back surface portion 22 to the needle tip 20a2 side in the longitudinal direction A, and the first back cutting surface portion 27 is formed by cutting the plate portion that will become the first plate-shaped portion 31. Furthermore, during the manufacturing of the main body portion 20a, the plate portion that will become the second plate-like portion 32 extends from the second back surface portion 23 to the needle tip 20a2 side in the longitudinal direction A, and the second back blade surface portion 28 is formed by cutting the plate portion that will become the second plate-like portion 32.

[0041] Here, the outer diameter OD of the main body portion 20a is 0.15 mm or more and 0.26 mm or less. The "outer diameter OD of the main body portion 20a" here refers to the maximum length obtained by comparing the maximum lengths in a cross-sectional view perpendicular to the longitudinal direction A at any position in the longitudinal direction A. It is particularly preferable that the outer diameter OD of the main body portion 20a is 0.15 mm or more and 0.20 mm or less. In addition, the blade surface length L1, which is the maximum length in the longitudinal direction A of the front blade surface 21 and the back blade surface 24, is 0.15 mm or more and 0.5 mm or less. It is particularly preferable that the blade surface length L1 is 0.15 mm or more and 0.4 mm or less. With the main body portion 20a, even when such a short blade surface length L1 is adopted, the vicinity of the needle tip 20a2 can be sharpened by having the shape described above, and the resistance to puncturing the skin can be reduced.

[0042] Further details of the main body 20a of this embodiment will be described below.

[0043] As shown in Figure 6, in this embodiment, the angle θ1 (hereinafter simply referred to as "cutting edge angle θ1") of the first cutting edge 29a and the second cutting edge 29b in a cross-sectional view perpendicular to the longitudinal direction A is less than 90 degrees. As described above, by forming the first back cutting edge portion 27 and the second back cutting edge portion 28 of the back cutting edge 24 so as to be connected to the needle tip 20a2 side in the longitudinal direction A with respect to the first back surface portion 22 and the second back surface portion 23, it becomes easier to make the cutting edge angle θ1 less than 90 degrees. And by making the cutting edge angle θ1 less than 90 degrees, the resistance to puncturing the skin can be further reduced even with a short blade length L1. It is more preferable that the cutting edge angle θ1 be 80 degrees or less, and particularly preferable that it be 70 degrees or less.

[0044] Further, as shown in FIGS. 3B and 3C, the first back blade surface portion 27 and the second back blade surface portion 28 have a length of 50% or more of the blade surface length L1 in the longitudinal direction A. That is, the length L2 in the longitudinal direction A of each of the first back blade surface portion 27 and the second back blade surface portion 28 is 50% or more of the blade surface length L1. By doing so, even if the blade surface length L1 is short, it becomes easier to secure the lengths of the first cutting edge 29a and the second cutting edge 29b respectively. Therefore, it is possible to suppress an increase in puncture resistance during the insertion of the main body portion 20a of the injection needle 20 to a predetermined depth of the skin. The blade surface length L1 of the present embodiment is the length in the longitudinal direction A of the front blade surface 21. Further, the first cutting edge 29a and the second cutting edge 29b preferably have a length extending over the entire width W1 of the front blade surface 21 in a top view of the main body portion 20a (see FIG. 3A). By doing so, it is possible to further suppress an increase in puncture resistance during the insertion of the main body portion 20a to a predetermined depth of the skin. The width W1 of the front blade surface 21 of the present embodiment is the same as the outer diameter OD of the main body portion 20a.

[0045] As shown in FIG. 3A, in a top view of the main body portion 20a, the angle θ2 formed by the first cutting edge 29a and the second cutting edge 29b (hereinafter, simply referred to as "cutting edge opening angle θ2") is preferably 90 degrees or less. By doing so, in a top view of the main body portion 20a (see FIG. 3A), the main body portion 20a can be made sharper toward the needle tip 20a2. Thereby, even if the blade surface length L1 is short, the puncture resistance to the skin can be further reduced. The cutting edge opening angle θ2 is more preferably 80 degrees or less, and particularly preferably 75 degrees or less. The cutting edge opening angle θ2 of the present embodiment is constant regardless of the position in the longitudinal direction A. That is, the cutting edge opening angle θ2 of the present embodiment is the same as the upper surface blade tip angle formed by the first cutting edge 29a and the second cutting edge 29b at the position of the needle tip 20a2 in a top view of the main body portion 20a (see FIG. 3A) regardless of the position in the longitudinal direction A. However, although details will be described later, the cutting edge opening angle θ2 may be configured to change depending on the position in the longitudinal direction A so as to be smaller in the vicinity of the needle tip 20a2 (see FIG. 8A).

[0046] As shown in FIG. 3C, in a side view of the main body portion 20a, the angle θ3 (hereinafter simply referred to as "side edge tip angle θ3") formed by the front side cutting edge surface 21 and the back side cutting edge surface 24 at the position of the needle tip 20a2 is preferably 45 degrees or less. By doing so, in a side view of the main body portion 20a (see FIG. 3C), the main body portion 20a can be made sharper toward the needle tip 20a2. Thereby, even with a short cutting edge length L1, the puncture resistance to the skin can be further reduced. The side edge tip angle θ3 is more preferably 40 degrees or less, and particularly preferably 35 degrees or less.

[0047] As shown in FIG. 3C, in a side view of the main body portion 20a, the inclination angle θ4 (hereinafter simply referred to as "blade surface angle θ4") of the front side inclined blade surface portion 26 with respect to the longitudinal direction A is preferably 45 degrees or less. By doing so, in a side view of the main body portion 20a (see FIG. 3C), the main body portion 20a can be made sharper toward the needle tip 20a2. Thereby, even with a short cutting edge length L1, the puncture resistance to the skin can be further reduced. The blade surface angle θ4 is more preferably 40 degrees or less, and particularly preferably 35 degrees or less.

[0048] As shown in FIG. 6, the angle θ5 (hereinafter simply referred to as "ridge angle θ5") in a cross-sectional view perpendicular to the longitudinal direction A of the ridge portion 29c formed by the intersection of the first back side blade surface portion 27 and the second back side blade surface portion 28 is not particularly limited, but is preferably less than 90 degrees as in this embodiment. By doing so, the ridge portion 29c also becomes more likely to function as a cutting edge for tearing the skin. Thereby, when the vicinity of the needle tip 20a2 of the main body portion 20a is inserted into the skin, the puncture resistance to the skin can be further reduced. The ridge angle θ5 is more preferably 80 degrees or less, and particularly preferably 70 degrees or less.

[0049] As shown in Figure 3C, in a side view of the main body 20a, the height H1 of the first back cutting surface 27 and the second back cutting surface 28 in the direction perpendicular to the longitudinal direction A is 50% or more of the height H2 of the main body 20a in the direction perpendicular to the longitudinal direction A. By doing so, as described above, it becomes easier to realize a configuration in which the first cutting edge 29a and the second cutting edge 29b have a length that extends across the entire width W1 of the front cutting surface 21 in a top view of the main body 20a (see Figure 3A).

[0050] For the main body portion 20a, stainless steel (SUS) is preferred, but it is not limited to this, and may be aluminum, aluminum alloy, titanium, titanium alloy, or other metals.

[0051] Next, with reference to Figures 7 to 8C, an injection needle 220 as another embodiment of the injection needle according to the present disclosure will be described. Figure 7 is a perspective view of the tip of the main body portion 220a of the injection needle 220. Figure 8A is an enlarged view of the tip of the main body portion 220a from a top view of the main body portion 220a. Figure 8B is an enlarged view of the tip of the main body portion 220a from a bottom view of the main body portion 220a. Figure 8C is an enlarged view of the tip of the main body portion 220a from a side view of the main body portion 220a. In Figures 8A to 8C, for the sake of explanation, the position of the tip surface 81b of the needle hub 81 in the needle holder 80 in which the injection needle 220 is held is indicated by a dashed line.

[0052] The injection needle 220 of this embodiment differs from the injection needle 20 described above (see Figures 1 to 6) in the configuration of the tip of the main body portion 220a, while other configurations are common. More specifically, the main body portion 220a of this embodiment differs from the main body portion 20a described above (see Figures 1 to 6) in that the front cutting surface 221 has a front cutting edge cutting surface portion 233 in addition to the front inclined cutting surface portion 26. Furthermore, the main body portion 220a of this embodiment differs from the main body portion 20a described above (see Figures 1 to 6) in that, in the longitudinal direction A, it has a needle base portion 225 located on the base end 20a1 side of the front cutting surface 221, having an outer peripheral surface 225a whose outer shape in a cross-sectional view perpendicular to the longitudinal direction A is substantially circular. Furthermore, the main body portion 220a of this embodiment differs from the main body portion 20a (see Figures 1 to 6) described above in that a stopper surface portion 234 is formed between the first back surface portion 22 and the second back surface portion 23, respectively, and the outer peripheral surface 225a of the needle base portion 225 described above. The main body portion 220a of this embodiment is the same as the main body portion 20a (see Figures 1 to 6) except for the differences described above. Therefore, only the differences described above will be explained here, and the common configuration will not be explained.

[0053] The main body portion 220a comprises a front blade surface 221, a first back surface portion 22, a second back surface portion 23, a back blade surface 24, and a needle base portion 225. The first back surface portion 22, the second back surface portion 23, and the back blade surface 24 are configured similarly to those of the main body portion 20a described above.

[0054] As shown in Figures 7, 8A, and 8C, the front cutting surface 221 of this embodiment comprises a front inclined cutting surface portion 26 and a front cutting edge cutting surface portion 233. The front inclined cutting surface portion 26 of this embodiment is composed of a planar inclined surface that is inclined with respect to the longitudinal direction A. The front cutting edge cutting surface portion 233 of this embodiment is connected to the needle tip 20a2 side relative to the front inclined cutting surface portion 26. The front cutting edge cutting surface portion 233 of this embodiment extends to the needle tip 20a2. As shown in Figure 8C, the inclination angle of the front cutting edge cutting surface portion 233 of this embodiment with respect to the longitudinal direction A is smaller than the inclination angle θ4 (cutting surface angle θ4) of the front inclined cutting surface portion 26. The front cutting edge cutting surface portion 233 of this embodiment extends substantially parallel to the longitudinal direction A. More specifically, the front cutting edge cutting surface portion 233 of this embodiment is formed by a plane substantially parallel to the longitudinal direction A. In other words, although the inclination angle in this embodiment is 0 degrees, the front cutting edge surface portion 233 may be inclined at an angle smaller than the inclination angle θ4 (cutting surface angle θ4).

[0055] The front cutting edge surface portion 233 is formed in a position on the needle tip side 20a2 of the tip opening 20b1 of the drug solution lumen 20b when viewed from above (see Figure 8A) of the main body portion 220a.

[0056] The first back-side cutting surface portion 27 has a first cutting edge 29a that extends to the needle tip 20a2 at a position where it intersects with the front-side cutting surface 221. More specifically, the first cutting edge 29a in this embodiment includes a base end portion 29a1 formed by the intersection of the first back-side cutting surface portion 27 and the front-side inclined cutting surface portion 26, and a needle tip portion 29a2 formed by the intersection of the first back-side cutting surface portion 27 and the front-side cutting edge portion 233. The cutting edge angle θ1 (see Figure 6) is the same at both the base end portion 29a1 and the needle tip portion 29a2.

[0057] The second back-side cutting surface portion 28 has a second cutting edge 29b that extends to the needle tip 20a2 at a position where it intersects with the front-side cutting surface 221. More specifically, the second cutting edge 29b in this embodiment includes a base end portion 29b1 formed by the intersection of the second back-side cutting surface portion 28 and the front-side inclined cutting surface portion 26, and a needle tip portion 29b2 formed by the intersection of the second back-side cutting surface portion 28 and the front-side cutting edge portion 233. The cutting edge angle θ1 (see Figure 6) is the same at both the base end portion 29b1 and the needle tip portion 29b2.

[0058] As shown in Figure 8A, the cutting edge opening angle θ2 is smaller at the front cutting edge surface 233 than at the front inclined cutting surface 26. Specifically, the second cutting edge opening angle θ2b at the front cutting edge surface 233 is smaller than the first cutting edge opening angle θ2a at the front inclined cutting surface 26. In this embodiment, the second cutting edge opening angle θ2b at the front cutting edge surface 233 is the same as the top cutting edge angle formed by the first cutting edge 29a and the second cutting edge 29b at the needle tip 20a2 in a top view of the main body 220a (see Figure 8A).

[0059] Thus, by having the front cutting edge portion 233 on the needle tip 20a2 side of the front inclined cutting edge portion 26 on the front cutting edge portion 221, the upper cutting edge angle can be made smaller compared to a configuration without the front cutting edge portion 233. As a result, the area near the needle tip 20a2 of the main body portion 220a can be sharpened more sharply in a top view of the main body portion 20a (see Figure 3A). Therefore, even with a short cutting edge length L1, the resistance to puncturing the skin can be further reduced.

[0060] Furthermore, as shown in Figures 7 to 8C, the main body portion 220a of this embodiment includes a needle base portion 225 located on the base end 20a1 side of the main body portion 220a in the longitudinal direction A, relative to the front blade surface 221. The needle base portion 225 of this embodiment has an outer peripheral surface 225a whose outer shape is substantially circular in a cross-sectional view perpendicular to the longitudinal direction A. The main body portion 220a of this embodiment is configured such that the needle base portion 225 is held by the needle hub 81 of the needle holder 80. More specifically, the needle base portion 225 of this embodiment is held by the needle hub 81 with a portion of its tip side protruding outward from the tip surface 81b of the needle hub 81, and its base end side housed in the through hole 81a (see Figure 2).

[0061] As shown in Figures 7 to 8C, the first back surface 22 and the second back surface 23 of this embodiment extend in the longitudinal direction A from the front blade surface 221 to the base end 20a1 (see Figure 2) of the main body 220a. Furthermore, the first back surface 22 and the second back surface 23 of this embodiment are connected to the outer peripheral surface 225a of the needle base 225 via a stopper surface 234 that faces the needle tip 20a2 side in the longitudinal direction A. In other words, in this embodiment, there is a step between the first back surface 22 and the second back surface 23 and the outer peripheral surface 225a of the needle base 225. The stopper surface 234 is provided at the position of this step.

[0062] The main body portion 220a is equipped with a stopper surface portion 234, which allows for control of the insertion depth of the main body portion 220a into the skin. In other words, when the main body portion 220a is inserted into the skin from the needle tip 20a2, the stopper surface portion 234 abuts against the skin surface, preventing further insertion into the skin. Thus, by providing the stopper surface portion 234 on the main body portion 220a, the insertion depth of the main body portion 220a into the skin can be controlled without using the tip surface 81b of the needle hub 81. Therefore, when assembling the injection needle 220 into the needle holder 80, fine adjustment of the amount of protrusion from the tip surface 81b of the main body portion 220a becomes unnecessary, improving the efficiency of assembling the injection needle 220 into the needle holder 80.

[0063] Figures 9 and 10 show a modified example of the main body portion 220a of this embodiment. In the main body portion 220a shown in Figures 9 and 10, the first back surface portion 22 and the second back surface portion 23 do not extend from the front cutting surface 221 to the base end 20a1 side of the main body portion 220a in the longitudinal direction A. More specifically, the base end 22a of the first back surface portion 22 shown in Figures 9 and 10 is located near the base end 27a of the first back cutting surface portion 27 in the longitudinal direction A. Furthermore, the base end 22a of the first back surface portion 22 shown in Figures 9 and 10 is located on the needle tip 20a2 side from the base end 221a of the front cutting surface 221 in the longitudinal direction A. Also, the base end 23a of the second back surface portion 23 shown in Figures 9 and 10 is located near the base end 28a of the second back cutting surface portion 28 in the longitudinal direction A. Furthermore, the base end 23a of the second back surface portion 23 shown in Figures 9 and 10 is located on the needle tip 20a2 side of the base end 221a of the front cutting surface 221 in the longitudinal direction A.

[0064] Furthermore, in the main body portion 220a shown in Figures 9 and 10, the first back surface portion 22 and the second back surface portion 23 are connected to the outer peripheral surface 225a of the needle base portion 225 via a sloping portion 236 that is inclined with respect to the longitudinal direction A. In other words, in the main body portion 220a shown in Figures 9 and 10, the sloping portion 236 is provided so that no step is formed between the first back surface portion 22 and the second back surface portion 23 and the outer peripheral surface 225a of the needle base portion 225.

[0065] In this way, by reducing the range of the first back surface portion 22 and the second back surface portion 23 in the longitudinal direction A, the effort required to form the planar first back surface portion 22 and the second back surface portion 23 on the outer surface of the tubular body, which has a circular cross-sectional shape perpendicular to the longitudinal direction A, can be reduced. Furthermore, by providing the aforementioned bevel portion 236, it is possible to suppress the formation of a step between each of the first back surface portion 22 and the second back surface portion 23 and the outer surface 225a of the needle base portion 225, which would increase the resistance to puncturing the skin. As a result, even if the first back surface portion 22 and the second back surface portion 23 do not extend from the front cutting surface 221 to the base end 20a1 (see Figure 2) of the main body portion 220a in the longitudinal direction A, it is possible to suppress an increase in puncture resistance when the main body portion 220a punctures the skin.

[0066] In the case of the main body portion 220a shown in Figures 9 and 10, the insertion depth of the main body portion 220a into the skin may be controlled by utilizing the tip surface 81b of the needle hub 81 (see the dashed line in Figures 8A to 8C).

[0067] The injection needle, injection needle assembly, and syringe relating to this disclosure are not limited to the specific configurations shown in the embodiments and modifications described above, and various modifications, changes, and combinations are possible without departing from the scope of the claims. For example, in the main body portion 20a described above (see Figures 1 to 6) in which the front cutting surface 21 is composed only of the front inclined cutting surface portion 26, the needle base portion 225 and stopper surface portion 234 shown in Figures 7 to 8C may be applied. Also, for example, in the main body portion 20a described above (see Figures 1 to 6) in which the front cutting surface 21 is composed only of the front inclined cutting surface portion 26, the needle base portion 225 and inclined surface portion 236 shown in Figures 9 and 10 may be applied.

[0068] This disclosure relates to injection needles, injection needle assemblies, and syringes.

[0069] 1: Syringe 10: Injection needle assembly 20, 220: Injection needle 20a, 220a: Main body 20a1: Base end of main body 20a2: Needle tip of main body 20b: Drug lumen 20b1: Tip opening 21, 221: Front cutting surface 22: First back surface 22a: Base end of first back surface 23: Second back surface 23a: Base end of second back surface 24: Back cutting surface 25, 225: Needle base 26: Front inclined cutting surface 27: First back cutting surface 27a: Base end of first back cutting surface 28: Second back cutting surface 28a: Base end of second back cutting surface 29a: First cutting edge 29a1: Base end side of first cutting edge 29a2: Needle tip side of first cutting edge 29b: Second cutting edge 29b1: Base end side of the second cutting edge 29b2: Needle tip side of the second cutting edge 29c: Ridge portion 30: Arc-shaped portion 31: First plate-shaped portion 32: Second plate-shaped portion 80: Needle holder 81: Needle hub 81a: Through hole 81b: Tip surface 82: Elastic body 83: Storage cylinder 83a: Insertion opening 83b: Male thread portion 86: Contact agent 100: Syringe body 170: Drug discharge tube portion 171: Outer cylinder 171a: Female thread portion 180: Barrel portion 181: Drug solution 190: Plunger 191: Gasket 192: Plunger 221a: Base end of the front cutting surface 225a: Outer peripheral surface of the needle base portion 233: Front cutting edge surface portion 234: Stopper surface portion 236: Inclined surface A: Longitudinal direction B: Circumferential direction C: Radial direction H1: Height of the first and second back blade surfaces H2: Height of the main body L1: Blade length L2: Length of the first and second back blade surfaces O: Axis of the main body OD: Outer diameter of the main body W1: Width of the front blade surface θ1: Cutting edge angle θ2: Cutting edge opening angle θ2a: First cutting edge opening angle θ2b: Second cutting edge opening angle θ3: Side cutting edge angle θ4: Inclination angle of the front inclined blade surface relative to the longitudinal direction (blade surface angle) θ5: Ridge angle

Claims

1. A tubular main body portion extending from the base to the tip of the needle, the main body portion includes a front inclined blade surface portion extending inclined with respect to the longitudinal direction of the main body portion, the front blade surface extending to the tip of the needle, a first and second planar back surface portion formed on the back side of the front blade surface at different positions in the circumferential direction of the main body portion, and a back blade surface portion including a first back blade surface portion located on the back side of the front blade surface, connected to the tip of the needle in the longitudinal direction relative to the first back surface portion, forming a first cutting edge that extends to the tip of the needle at a position intersecting the front blade surface, and a second back blade surface portion connected to the tip of the needle in the longitudinal direction relative to the second back surface portion, forming a second cutting edge that extends to the tip of the needle at a position intersecting the front blade surface, The first and second back surfaces extend substantially parallel to the longitudinal direction, or extend inclined with respect to the longitudinal direction so as they approach the needle tip; the first and second back surface portions of the back cutting surface form a ridge portion at the position where they intersect, extending to the needle tip; the outer diameter of the main body is 0.15 mm or more and 0.26 mm or less; and the blade length, which is the maximum length in the longitudinal direction of the front and back cutting surfaces, is 0.15 mm or more and 0.5 mm or less.

2. The injection needle according to claim 1, wherein the angle of the first cutting edge and the second cutting edge in a cross-sectional view perpendicular to the longitudinal direction is less than 90 degrees.

3. The injection needle according to claim 1 or 2, wherein the first back cutting surface portion and the second back cutting surface portion have a length of 50% or more of the cutting surface length in the longitudinal direction.

4. In a top view of the main body portion viewed from the side of the front cutting surface, the angle formed by the first cutting edge and the second cutting edge is 90 degrees or less, as described in claim 1 or 2.

5. The injection needle according to claim 4, wherein the front cutting surface is connected to the front inclined cutting surface portion and extends to the needle tip, and comprises a front cutting edge cutting surface portion having a smaller angle of inclination with respect to the longitudinal direction than the front inclined cutting surface portion, and in a top view of the main body portion viewed from the side of the front cutting surface, the angle formed by the first cutting edge and the second cutting edge is smaller at the position of the front cutting edge cutting surface portion than at the position of the front inclined cutting surface portion.

6. The injection needle according to claim 1 or 2, wherein, in a side view of the main body, the angle formed by the front cutting surface and the back cutting surface at the position of the needle tip is 45 degrees or less.

7. In a side view of the main body, the inclination angle of the front inclined blade surface with respect to the longitudinal direction is 45 degrees or less, as described in claim 1 or 2.

8. The injection needle according to claim 1 or 2, wherein the main body portion has an outer peripheral surface whose outer shape is substantially circular in a cross-sectional view perpendicular to the longitudinal direction, and includes a needle base portion located on the base end side of the main body portion from the front cutting surface in the longitudinal direction, and the first back portion and the second back portion extend from the front cutting surface to the base end side of the main body portion in the longitudinal direction, and are connected to the outer peripheral surface of the needle base portion via a stopper surface portion facing the needle tip side in the longitudinal direction.

9. The injection needle according to claim 1 or 2, wherein the main body portion has an outer peripheral surface whose outer shape is substantially circular in a cross-sectional view perpendicular to the longitudinal direction, and includes a needle base portion located on the base end side of the main body portion from the front cutting surface in the longitudinal direction, and the first back portion and the second back portion do not extend from the front cutting surface to the base end side of the main body portion in the longitudinal direction, and are connected to the outer peripheral surface of the needle base portion via an inclined surface portion that is inclined with respect to the longitudinal direction.

10. An injection needle assembly comprising the injection needle described in claim 8 and a needle holder for holding the injection needle.

11. A syringe comprising: an injection needle assembly according to claim 10; and a syringe body connectable to the needle holder of the injection needle assembly.

Images