Syringe

Abstract

This syringe is provided with a barrel which is formed in the shape of a tube with a distal end and a base end and which has an ejection hole provided on the distal end for ejecting a drug; a filter which is arranged on the base end side with respect to the ejection hole inside of the barrel; and a holding member which holds the filter and which has a base-end part that is arranged on the base end side with respect to the filter. In the base-end part, a flow path is provided through which the drug flows; on the base end side of the filter, a base end space is provided where the drug in the flow path enters; on the distal end side of the filter, a distal end space is provided into which the drug flows through the filter from the base end space; when viewed from the axial direction of the barrel, the area of the ejection hole is less than the area of the base end space, less than the area of the distal end space and less than the area of the flow path.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2020-179783, the entire disclosure of which is incorporated herein by reference. [Technical Field]

[0002] The present invention relates to a syringe equipped with a filter that can filter out particles in a drug when the drug is administered. [Background technology]

[0003] Conventionally, a cylinder containing a filter body has been known as a syringe for administering medicine (Patent Document 1). A fixing member with an injection needle attached thereto is detachable from the tip of the cylinder. Also, a filter body is disposed within the tip of the cylinder, which filters out foreign matter and allows only the drug solution to flow. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent No. 6464430 Summary of the Invention [Problem to be solved by the invention]

[0005] However, particles may be encapsulated or formed in the medicine filled into such a cylinder. Such particles may be, for example, silicone oil, glass, plastic, or rubber from the syringe, or protein aggregates or powder from the medicine. While it may be possible to filter out these particles from the cylinder using a filter, this may increase the resistance to injection when administering the medicine.

[0006] An object of the present invention is to provide a syringe that, when administering a medicine, can capture particles in the medicine while suppressing resistance to the injection of the medicine. [Means for solving the problem]

[0007] The syringe of the present invention is a syringe for administering a drug, and comprises: a barrel formed in a cylindrical shape having a tip end and a base end, with an outlet hole at the tip end for injecting the drug contained inside to the outside; a filter arranged inside the barrel on the base end side of the outlet hole; and a holding member configured to hold the filter arranged inside the barrel and having a base end portion arranged on the base end side of the filter, wherein the base end portion of the holding member is provided with a flow path through which the drug flows from the base end side to the tip end side, a base end space is provided on the base end side of the filter into which the drug that has flowed through the flow path flows, and a tip end space is provided on the tip end side of the filter into which the drug flows from the base end space via the filter, and when viewed from the axial direction of the barrel, the area of ​​the outlet hole is smaller than the area of ​​the base end space, smaller than the area of ​​the tip end space, and smaller than the area of ​​the flow path.

[0008] In the syringe, when viewed from the axial direction of the barrel, an area of ​​the flow path in the holding member may be smaller than an area of ​​the base-end space.

[0009] In addition, in the syringe, the base end portion of the holding member may have a base end surface that serves as an abutment surface against which a piston inserted into the barrel from the base end side can abut, and the abutment surface may be configured so that the tip surface of the piston makes surface contact around the entire circumference of the barrel. Holding member Holding member [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of a pre-filled syringe equipped with a syringe according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view of the area indicated by III in FIG. [Figure 4]FIG. 4 is a schematic diagram illustrating the attachment of a filter to the syringe. [Figure 5] FIG. 5 is a side view of a pre-filled syringe according to a modified example. [Figure 6] FIG. 6 is an enlarged cross-sectional view of the area indicated by VI in FIG. [Figure 7] FIG. 7 is a side view of a syringe-equipped container according to a modified example. [Figure 8] FIG. 8 is an enlarged cross-sectional view of the area indicated by VIII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a pre-filled syringe equipped with a syringe according to an embodiment of the present invention will be described with reference to FIGS.

[0012] As shown in Figures 1 and 2, the prefilled syringe 1 includes a syringe 2 for administering a drug. The prefilled syringe 1 also includes a piston 3 that is inserted into the syringe 2 (see Figure 2). The prefilled syringe 1 also includes an injection needle 4 that is connected to the syringe 2. The prefilled syringe 1 also includes a cap 5 that caps the injection needle 4. The drug is a liquid drug, such as a protein preparation.

[0013] The syringe 2 includes a cylindrical barrel 6 having a distal end 60 and a proximal end 61, a filter 7 disposed inside the barrel 6, and a holding member 8 configured to hold the filter 7. The syringe 2 is also substantially cylindrical. The syringe 2 of this embodiment includes a single filter 7, but may also include a plurality of overlapping filters 7.

[0014] Hereinafter, in the prefilled syringe 1 and the syringe 2, the side where the tip portion 60 is arranged (upper side in Figs. 1 to 3) will be simply referred to as the "tip side," and the side where the base end portion 61 is arranged (lower side in Figs. 1 to 3) will be simply referred to as the "base side." Additionally, the axial direction of the syringe 2 will also be simply referred to as the "axial direction."

[0015] The barrel 6 is a member that contains a drug inside. In addition to a distal end 60 and a proximal end 61, the barrel 6 of this embodiment includes a cylindrical portion 62 that connects the distal end 60 and the proximal end 61 (see FIG. 2). The barrel 6 also has a flange portion 63 that extends outward (in the radially outward direction of the cylindrical portion 62) from the entire outer periphery of the other end in the axial direction of the cylindrical portion 62.

[0016] The barrel 6 is formed, for example, from a transparent material that can withstand the internal pressure applied when administering a drug. Specifically, the material of the barrel 6 is a resin containing a cyclic olefin such as norbornene as a repeating unit. More specifically, the material of the barrel 6 is a transparent resin such as COP (cycloolefin polymer), which is a homopolymer of a cyclic olefin, or COC (cycloolefin copolymer), which is a copolymer of a cyclic olefin and ethylene or the like. The barrel 6 may also be made of PP (polypropylene) or glass.

[0017] It should be noted that the inner peripheral surface of the barrel 6 (for example, the inner peripheral surface of the cylindrical portion 62) is coated with silicone oil in order to reduce the sliding resistance of the piston 3 against the inner peripheral surface of the barrel 6.

[0018] The tip portion 60 of the barrel 6 is provided at one end in the axial direction of the tubular portion 62 (specifically, the end portion on the tip side). The tip portion 60 is provided with an ejection hole 64 for ejecting the medicine contained inside to the outside. In the barrel 6 of this embodiment, the ejection hole 64 is a needle hole through which the injection needle 4 is inserted.

[0019] When the needle inserted into the ejection hole 64 is, for example, 27 gauge, the inner diameter of the ejection hole 64 is 0.27 mm, and the area of ​​the ejection hole 64 when viewed from the axial direction is 0.057 mm. 2 In addition, when the needle inserted into the injection hole 64 is 29 gauge, the inner diameter of the injection hole 64 is 0.21 mm, and the area of ​​the injection hole 64 when viewed from the axial direction is 0.035 mm 2 The cross-sectional area of ​​the injection hole 64 in a direction perpendicular to the axis is approximately constant.

[0020] The base end surface 600 of the tip portion 60 is formed so as to close the edge portion located on the tip side of the cylindrical portion 62 except for the spout hole 64. The base end surface 600 extends, for example, in an inclined state so that the radially inward side is positioned closer to the tip side.

[0021] The area of ​​the cylindrical portion 62 when viewed from the axial direction (the cross-sectional area of ​​the cylindrical portion 62 in a direction perpendicular to the axial direction) is, for example, approximately constant, specifically, 12.56 mm 2 More than 314mm 2 The inner diameter of the cylindrical portion 62 is, for example, approximately constant, and specifically, is not less than 4 mm and not more than 20 mm.

[0022] The filter 7 is attached to the retaining member 8. The retaining member 8 is housed in the barrel 6 while being pressed against the barrel 6. Specifically, at least a portion of the outer circumferential surface of the retaining member 8 is in close contact with the inner circumferential surface of the barrel 6.

[0023] Furthermore, the holding member 8 is made of a flexible material. The holding member 8 of this embodiment is more flexible than the barrel 6. Specifically, the material of the holding member 8 is, for example, a resin, rubber, elastomer, or the like that is softer than the material of the barrel 6. The flexibility of the barrel 6 and the holding member 8 can be confirmed, for example, by measuring durometer hardness. By making the holding member 8 of such a material, the flexibility of the holding member 8 relative to the barrel 6 is ensured, and cracks in the barrel 6 can be prevented.

[0024] The holding member 8 has a base end portion 80 that is disposed closer to the base end than the filter 7. The holding member 8 of this embodiment is composed only of the base end portion 80. The base end portion 80 of the holding member 8 is provided with a flow path 81 through which the drug flows from the base end side to the tip end side.

[0025] The base end portion 80 of the holding member 8 has a contact surface 800 as a base end face 800 against which the piston 3 inserted into the barrel 6 from the base end side can come into contact. The base end portion 80 has a cylindrical shape whose tip side is closed by a disk with a through hole provided in the center.

[0026] The contact surface 800 of the base end portion 80 has a shape corresponding to the tip surface 33 of the piston 3. The contact surface 800 is configured so that the tip surface 33 of the piston 3 comes into surface contact with the barrel 6 over the entire circumferential direction.

[0027] The abutment surface 800 of this embodiment includes, for example, as shown in Figure 3, a base-end abutment surface 801 located on the base-end side, a tip-end abutment surface 802 located on the tip-end side, and a connecting abutment surface 803 connecting the base-end abutment surface 801 and the tip-end abutment surface 802.

[0028] The base end contact surface 801 is, for example, a surface that is approximately perpendicular to the axial direction. The tip end contact surface 802 is, for example, a surface that is approximately perpendicular to the axial direction.

[0029] The connection abutment surface 803 is a surface extending along the axial direction. For example, the central portion of the connection abutment surface 803 in the axial direction is recessed radially outward.

[0030] The proximal portion 80 of this embodiment includes an attachment site 82 to which the filter 7 is attached, and leg portions 83 extending from the attachment site 82. In this proximal portion 80, the attachment site 82 is provided on the distal side, and the leg portions 83 are arranged on the proximal side.

[0031] The flow path 81 is provided in an attachment portion 82 of the base end portion 80. In this embodiment, the area of ​​the flow path 81 when viewed from the axial direction (the cross-sectional area of ​​the flow path 81 in a direction perpendicular to the axis) is constant. In addition, the area of ​​the flow path 81 when viewed from the axial direction is 0.64 mm 2 More than 1.33mm 2The inner diameter of the flow path 81 in this embodiment is constant. The inner diameter of the flow path 81 is, for example, 0.3 mm or more and 0.9 mm or less. The flow path 81 is a through hole, and specifically, is cylindrical, but may also be rectangular.

[0032] The mounting portion 82 has a shape in which its outer periphery protrudes toward the tip. In this embodiment, the outer periphery of the mounting portion 82 is slightly spaced from the inner periphery of the barrel 6 (specifically, the inner periphery of the tubular portion 62 of the barrel 6). Furthermore, the mounting portion 82 has a tapered shape in which the outer diameter decreases toward the tip. The mounting portion 82 also has an outer periphery mounting portion 820 that forms the outer periphery, and an inner periphery mounting portion 821 that is located radially inward of the outer periphery mounting portion 820 and defines the flow path 81.

[0033] Furthermore, in the mounting region 82, an outer peripheral leading end surface 822, which is the leading end surface of the outer peripheral mounting portion 820, is located further forward than an inner peripheral leading end surface 823, which is the leading end surface of the inner peripheral mounting portion 821. In other words, the leading end surface of the mounting region 82 is recessed in the circumferential center. The outer peripheral mounting portion 820 has a shoulder portion 824 as the outer peripheral portion on the leading end side.

[0034] Leg portions 83 have a shape in which the outer periphery protrudes toward the base end. A base end surface 830 of leg portions 83 forms the abutment surface 800 of base end portion 80. The outer periphery of leg portions 83 is in surface contact with the inner periphery of barrel 6 (specifically, the inner periphery of tubular portion 62 of barrel 6). In this way, the outer periphery of leg portions 83 is in close contact with the inner periphery of barrel 6, so that the drug reliably passes through flow path 81 of holding member 8 and is filtered by filter 7.

[0035] The filter 7 is a filter for filtering the medicine, and is disposed inside the barrel 6 closer to the base end than the outlet hole 64.

[0036] A base-end space 72 is provided on the base end side of the filter 7, into which the drug that has flowed through the flow path 81 flows. A tip-end space 71 is provided on the tip end side of the filter 7, into which the drug flows from the base-end space 72 via the filter 7. The filtration area of ​​the filter 7 is the area of ​​the tip-end edge of the base-end space 72 and the area of ​​the base-end edge of the tip-end space 71. The area of ​​the tip-end edge of the base-end space 72 is equal to the area of ​​the base-end edge of the tip-end space 71, for example.

[0037] The filter 7 may be, for example, a membrane, a mesh, a sintered body, a foam body, etc. The material of the filter 7 is resin, ceramic, metal, paper, etc.

[0038] The filter 7 is, for example, a membrane filter, but may also be a pre-filter.

[0039] The filter 7 of this embodiment is attached to the distal end surface 804 of the base end portion 80 of the holding member 8. Specifically, the filter 7 is welded to the distal end surface 804. More specifically, the filter 7 is welded to the outer peripheral distal end surface 822 of the outer mounting portion 820. This welding is ultrasonic welding, but other welding methods such as heat welding may also be used. The filter 7 may also be adhesively attached to the distal end surface 804.

[0040] 4, before the filter 7 is welded, the base-side portion 80 (e.g., the outer peripheral mounting portion 820) has a protrusion 825 that protrudes toward the tip side. When the filter 7 is welded, the protrusion 825 melts and spreads, so that after the filter 7 is welded, the tip surface 804 of the base-side portion 80 becomes a substantially flat surface.

[0041] The tip space 71 is defined by the inner circumferential surface 65 of the barrel 6 (specifically, the base end surface 600 of the tip portion 60) and the filter 7 (specifically, the tip side surface of the filter 7). The tip space 71 is continuous with the pouring hole 64.

[0042] Furthermore, the tip side space 71 has a shape in which, for example, the area when viewed from the cylindrical direction (cross-sectional area in a direction perpendicular to the axis) decreases from the base end side toward the tip side, that is, a tapered shape in which the area when viewed from the cylindrical direction (cross-sectional area in a direction perpendicular to the axis) decreases toward the tip side. The tip side space 71 in this embodiment is approximately cylindrical. This tip side space 71 has a shape in which, for example, the inner diameter decreases from the base end side toward the tip side, that is, a tapered shape in which the inner diameter decreases toward the tip side. Furthermore, the tip side space 71 has a shape in which the distance between the filter 7 and the base end face 600 of the tip portion 60 of the barrel 6 decreases toward the outer periphery. As a result, when administering a drug, the drug solution is pushed out into the tip side space 71 in a state in which it can easily move from the outer periphery side toward the cylindrical axis side in the circumferential direction, thereby reducing the pouring resistance. The tip side space 71 may be in the shape of a square tube.

[0043] The base end portion of the tip end space 71, i.e., the portion of the tip end space 71 with the largest area (e.g., inner diameter), is aligned with the shoulder portion 824 in the axial direction of the barrel 6, and its inner diameter is approximately the same size as the outer diameter of the shoulder portion of the retaining member 8.

[0044] The base-side space 72 is defined by the filter 7 (specifically, the base-side side surface of the filter 7) and a tip surface 804 of the base-side portion 80 (specifically, an inner circumferential tip surface 823 of the inner circumferential mounting portion 821 and an inner circumferential mounting surface 826 that is the inner circumferential surface of the outer circumferential mounting portion 820). The base-side space 72 is formed by the inner circumferential tip surface 823 of the inner circumferential mounting portion 821 being recessed toward the base end relative to the outer circumferential tip surface 822 of the outer circumferential mounting portion 820, that is, by the tip surface of the mounting portion 82 being recessed toward the base end.

[0045] The base-end space 72 is continuous with the flow path 81. The base-end space 72 has a tapered shape, for example, in which the area increases from the base end toward the tip end when viewed from the axial direction, i.e., the area increases toward the tip end. The base-end space 72 in this embodiment is substantially cylindrical. The base-end space 72 has a tapered shape, for example, in which the inner diameter increases from the base end toward the tip end. The angle of inclination of the inner mounting surface 826 of the outer mounting portion 820, which defines the base-end space 72, relative to the axial direction is smaller than the angle of inclination of the base-end end surface 600 of the tip portion 60, which defines the tip end space 71, relative to the axial direction. The base-end space 72 may also have a rectangular cylindrical shape.

[0046] In the above-described syringe 2, the filter 7 is sandwiched between the barrel 6 and the base end portion 80 of the holding member 8. Specifically, the filter 7 is sandwiched in the axial direction between the base end surface 600 of the tip portion 60 of the barrel 6 (specifically, the base end edge 601 of the base end surface 600) and the shoulder portion 824 of the base end portion 80. This makes it difficult for the filter 7 to come off from the base end portion 80 even if pressure is applied to the filter 7 when administering the medicinal liquid.

[0047] From the base end to the tip end, the flow path 81, the base end space 72, the tip end space 71, and the ejection hole 64 are arranged in this order. In the syringe 2 of this embodiment, the central axis of the flow path 81, the central axis of the base end space 72, and the central axis of the tip end space 71 all coincide with the central axis of the ejection hole 64. This ensures a good flow of the drug from the flow path 81 to the ejection hole 64 when the drug is administered.

[0048] The dimension L81 in the axial direction of the flow path 81 is larger than the dimension L72 in the axial direction of the base-end space 72. In addition, the dimension L71 in the axial direction of the tip-end space 71 (specifically, the dimension at the central axis of the tip-end space 71) is larger than the dimension L72 in the axial direction of the base-end space 72.

[0049] When viewed from the axial direction, the area of ​​the spouting hole 64 is smaller than the area of ​​the base end space 72, smaller than the area of ​​the tip end space 71, and smaller than the area of ​​the flow path 81. This means that the area of ​​the spouting hole 64 is smaller than the area of ​​any portion of the base end space 72 in the axial direction, smaller than the area of ​​any portion of the tip end space 71 in the axial direction, and smaller than the area of ​​any portion of the flow path 81 in the axial direction. Specifically, the area of ​​the spouting hole 64 is smaller than the area of ​​the base end space 72, smaller than the maximum area of ​​the tip end space 71 (the area at the base end edge of the tip end space 71), and smaller than the area of ​​the flow path 81.

[0050] Furthermore, when viewed from the axial direction, the area of ​​the flow path 81 is smaller than the area of ​​the base-end space 72. This means that the area of ​​the flow path 81 is smaller than the area of ​​any portion of the base-end space 72 in the axial direction.

[0051] Specifically, the inner diameter R64 of the spout 64 is smaller than the inner diameter R72 of the base end space 72, smaller than the maximum inner diameter R71 of the tip end space 71 (the inner diameter at the base end edge of the tip end space 71), and smaller than the inner diameter R81 of the flow path 81. In addition, the inner diameter R81 of the flow path 81 is smaller than the inner diameter R72 of the base end space 72.

[0052] Regarding such dimensional relationships, experiments were conducted by combining a barrel 6 having an inner diameter R64 of the dispensing hole 64 of 0.27 mm and 0.21 mm with a retaining member 8 having an inner diameter R81 of the flow path 81 of 0.3 mm, 0.6 mm, and 0.9 mm and an inner diameter R72 of the base end space 72 of 0.6 mm, 2.1 mm, and 3.6 mm, to examine the effect on dispensing resistance (specifically, sliding load).

[0053] The results of this experiment are as follows. When the inner diameter R72 of the base-end space 72 was 0.6 mm, an increase in the sliding load was confirmed. When the inner diameter R72 of the base-end space 72 was 2.1 mm or 3.6 mm, no significant change in the sliding load was observed. Furthermore, when the inner diameter R81 of the flow path 81 was changed within the above range, no significant change in the sliding load was observed.

[0054] For example, the inner diameter R81 of the flow path 81 is preferably greater than 1 and less than 5 times the inner diameter R64 of the spout hole 64, and is desirably 1.1 to 4.3 times the inner diameter R64 of the spout hole 64. When the inner diameter R64 of the spout hole 64 is 0.21 mm or 0.27 mm, the inner diameter R81 of the flow path 81 can be selected from 0.3 mm, 0.6 mm, and 0.9 mm. Furthermore, for example, the inner diameter R72 of the base-end space 72 (the filtration area of ​​the filter 7) is preferably greater than 5 and less than 20 times the inner diameter R64 of the spout hole 64, and is desirably greater than 7 and less than 18 times the inner diameter R64 of the spout hole 64. When the inner diameter R64 of the spout hole 64 is 0.21 mm or 0.27 mm, the inner diameter R72 of the base-end space 72 can be selected from 2.1 mm and 3.6 mm. If the inner diameters R72, R71 of the base end space 72 and the tip end space 71 are within this range, it is possible to reduce the discharge resistance while ensuring a sufficient filtration area when administering a drug.

[0055] The syringe 2 of this embodiment is sterilized by radiation such as gamma rays. This sterilization may be performed using a gas such as ethylene oxide gas, or may be performed in an autoclave.

[0056] The piston 3 is a member that is operated when dispensing the medicine in the barrel 6. The piston 3 of this embodiment has an axial rod portion 30, a gasket 31 that is attached to one end of the rod portion 30 in the longitudinal direction and that is in close contact with the entire inner circumferential surface of the tubular portion 62 of the barrel 6, and an operating portion 32 that is attached to the other end of the rod portion 30 in the longitudinal direction.

[0057] In the piston 3 of this embodiment, the tip surface 33 is formed by the tip surface of the gasket 31. Specifically, during administration of a drug, the tip surface 33 abuts at least against the base-end abutment surface 801 of the base-end portion 80 of the holding member 8, and more specifically, it abuts against the connecting abutment surface 803 in addition to the base-end abutment surface 801.

[0058] The piston 3 also has a contact portion 34 that contacts the inner peripheral surface of the barrel 6, and a protruding portion 35 that protrudes from the tip surface of the contact portion 34. The tip surface of the contact portion 34 contacts a base-end contact surface 801, and the tip surface of the protruding portion 35 contacts a tip-end contact surface 802. The outer peripheral surface of the protruding portion 35 contacts a connection contact surface 803.

[0059] The injection needle 4 is a member for administering the medicine in the barrel 6 to a patient. The tip of the injection needle 4 is covered with a cap 5.

[0060] According to the syringe 2 described above, even if particles are present in the medicine contained in the barrel 6, the particles can be captured by the filter 7 when the medicine is administered. Furthermore, the medicine flows through the flow path 81, the base end space 72, and the tip end space 71, which have a larger area (e.g., inner diameter) than the outlet hole 64, and is then injected from the outlet hole 64. This reduces the resistance when the medicine flows through the flow path 81, the base end space 72, and the tip end space 71, and as a result, reduces the resistance to the medicine being injected.

[0061] In the syringe 2 of this embodiment, the area (e.g., inner diameter) of the flow path 81 is small and the area (e.g., inner diameter) of the base end space 72 is large, so that the amount of drug remaining in the flow path 81 can be reduced while ensuring the area with which the drug comes into contact on the filter 7 (the filtration area by the filter 7), and the amount of residual liquid can be reduced while suppressing the discharge resistance.

[0062] Furthermore, in the syringe 2 of this embodiment, when administering the drug, the tip surface 33 of the piston 3 moves until it comes into surface contact with the abutment surface 800 of the holding member 8 around the entire circumference, thereby reducing residual liquid between the piston 3 and the holding member 8 and reducing the amount of residual drug liquid in the barrel 6.

[0063] The syringe of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, or part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

[0064] The configuration of the holding member 8 may be different from the configuration described above. For example, the contact surface 800 of the base end portion 80 may have a different shape as long as it matches the shape of the contact surface 33 of the piston 3.

[0065] Specifically, although the connection abutment surface 803 in the above embodiment extends along the axial direction, it may include a portion extending in a direction inclined relative to the axial direction. More specifically, as shown in Figures 5 and 6, the connection abutment surface 803 may include a first connection abutment surface 803a that is a surface approximately perpendicular to the axial direction, and second connection abutment surfaces 803b and 803c that are a pair of surfaces extending along the axial direction from both end edges of the first connection abutment surface 803a.

[0066] Specifically, the base-end-side contact surface 801 in the above embodiment is a surface that is approximately perpendicular to the axial direction, but may include a portion that is inclined at an angle other than perpendicular to the axial direction. More specifically, as shown in Figures 7 and 8, the base-end-side contact surface 801 may include a first base-end-side contact surface 801a that is a surface that is approximately perpendicular to the axial direction, and a second base-end-side contact surface 801b that is a surface that extends further inward in the radial direction from the radially inward edge of the first base-end-side contact surface 801a and is inclined so that the portion closer to the radially inward side is positioned closer to the tip.

[0067] Even with this configuration, the tip surface 33 of the piston 3 moves until it makes surface contact with the abutment surface 800 of the holding member 8 around the entire circumference, thereby reducing residual liquid between the piston 3 and the holding member 8 and reducing the amount of residual drug liquid in the barrel 6.

[0068] In the above embodiment, the retaining member 8 was composed of a base end portion 80, but it may also be composed to include a tip end portion that is positioned more distal than the filter 7, either integral with or separate from the base end portion 80.

[0069] Furthermore, in the holding member 8 of the above embodiment, the inner diameter of the flow path 81 is smaller than the inner diameter of the base-end space 72, but it may be approximately the same as the inner diameter of the base-end space 72.

[0070] In the holding member 8 of the above embodiment, the abutment surface 800 of the base-end side portion 80 is configured so that the tip surface 33 of the piston 3 comes into surface contact with the barrel 6 over the entire circumferential direction, but the abutment surface 800 may be configured so that the abutment surface 800 comes into surface contact with only a portion of the tip surface 33 of the piston 3 in the circumferential direction. For example, it is conceivable to provide recesses or protrusions intermittently in the circumferential direction on the base-end side abutment surface 801 of the abutment surface 800 of the base-end side portion 80.

[0071] In the syringe 2 of the above embodiment, the distal space 71 has a tapered shape with an inner diameter that decreases toward the distal end, but it may have another shape, such as a shape with a uniform inner diameter. In this case, the proximal end surface 600 may extend, for example, in a direction perpendicular to the axial direction.

[0072] The base end space 72 has a tapered shape with an inner diameter that decreases toward the tip end, but may have another shape, such as a shape with a uniform inner diameter.

[0073] Furthermore, the dimension of the flow path 81 in the axial direction may be equal to or smaller than the dimension of the base end space 72 in the axial direction.

[0074] Furthermore, the dimension in the axial direction of the distal end space 71 may be equal to or smaller than the dimension in the axial direction of the proximal end space 72. In this case, for example, it is conceivable to reduce the inclination angle of the proximal end face 600 of the distal end portion 60 of the barrel 6 with respect to the cylindrical axis, and then position the proximal end portion 80 of the holding member 8 at a position where it abuts against the proximal end face 600, or to increase the dimension in the axial direction of the proximal end portion 80 of the holding member 8.

[0075] According to the present invention, it is possible to provide a syringe that can capture particles in a medicine while suppressing resistance to the injection of the medicine when administering the medicine.

[0076] The syringe of the present invention is a syringe for administering a drug, and comprises: a barrel formed in a cylindrical shape having a tip end and a base end, with an outlet hole at the tip end for injecting the drug contained inside to the outside; a filter arranged inside the barrel on the base end side of the outlet hole; and a holding member configured to hold the filter arranged inside the barrel and having a base end portion arranged on the base end side of the filter, wherein the base end portion of the holding member is provided with a flow path through which the drug flows from the base end side to the tip end side, a base end space is provided on the base end side of the filter into which the drug that has flowed through the flow path flows, and a tip end space is provided on the tip end side of the filter into which the drug flows from the base end space via the filter, and when viewed from the axial direction of the barrel, the area of ​​the outlet hole is smaller than the area of ​​the base end space, smaller than the area of ​​the tip end space, and smaller than the area of ​​the flow path.

[0077] With this configuration, even if particles are present in the medicine contained in the barrel, the particles can be captured by the filter when the medicine is administered.Furthermore, since the medicine flows through the flow path, base end space, and tip end space, which have a larger area than the outlet hole, and is then injected from the outlet hole, resistance when flowing through the flow path, base end space, and tip end space can be reduced, and as a result, resistance to the injection of the medicine can be reduced.

[0078] In the syringe, when viewed from the axial direction of the barrel, an area of ​​the flow path in the holding member may be smaller than an area of ​​the base-end space.

[0079] With this configuration, the area of ​​the flow path is reduced and the area of ​​the base-end space is increased, so that the amount of drug remaining in the flow path can be reduced while ensuring the area where the drug comes into contact with the filter (filtration area), and the amount of residual liquid can be reduced while suppressing the discharge resistance.

[0080] In addition, in the syringe, the base end portion of the holding member may have a base end surface that serves as an abutment surface against which a piston inserted into the barrel from the base end side can abut, and the abutment surface may be configured so that the tip surface of the piston makes surface contact around the entire circumference of the barrel.

[0081] With this configuration, when administering the medicine, the tip surface of the piston moves until it makes surface contact with the abutment surface of the holding member around the entire circumference, thereby reducing residual liquid between the piston and the holding member and reducing the amount of residual medicine in the barrel. [Explanation of symbols]

[0082] 1...container, 2...syringe, 3...piston, 4...injection needle, 5...cap, 6...barrel, 7...filter, 8...holding member, 30...rod portion, 31...gasket, 32...operating portion, 33...contact surface (tip surface), 34...adhering portion, 35...protruding portion, 60...tip portion, 61...base end portion, 62...cylindrical portion, 63...flange portion, 64...discharge hole, 65...inner circumferential surface, 71...tip side space, 72...base side space, 80...base side portion, 81...flow path, 82...mounting portion, 83...leg portion, 600...base side end surface , 601...base end edge, 800...abutment surface (base end end surface), 801...base end abutment surface, 801a...first base end abutment surface, 801b...second base end abutment surface, 802...tip end abutment surface, 803...connection abutment surface, 803a...first connection abutment surface, 803b...second connection abutment surface, 803c...second connection abutment surface, 804...tip surface, 820...mounting outer periphery, 821...mounting inner periphery, 822...outer periphery tip surface, 823...inner periphery tip surface, 824...shoulder, 825...protrusion, 826...mounting inner periphery surface, 830...base end surface

Claims

1. A syringe for administering a drug, comprising: a barrel formed in a cylindrical shape having a tip end and a base end, the tip end having an ejection hole for ejecting the medicine contained therein to the outside; a filter disposed inside the barrel on the proximal side of the pouring hole; a retaining member configured to retain the filter disposed inside the barrel, the retaining member having a proximal portion disposed proximal to the filter, the base end portion includes an attachment portion to which the filter is attached and leg portions extending from the attachment portion toward the base end, The outer circumferential surface of the attachment portion has a smaller diameter than the outer circumferential surface of the leg portion, The outer peripheral surface of the leg portion is in surface contact with the inner peripheral surface of the barrel, the mounting portion has an outer mounting portion and an inner mounting portion located radially inward of the outer mounting portion and located on the base end side of a tip end surface of the outer mounting portion, a flow path through which a drug flows from the base end side to the tip end side is provided in the base end side portion of the holding member, a base-end space into which the drug that has flowed through the flow path flows is provided on the base-end side of the filter; a distal end space into which a drug flows from the base end space through the filter is provided on the distal end side of the filter, a syringe, wherein, when viewed from the axial direction of the barrel, the area of ​​the ejection hole is smaller than the area of ​​the base end space, the area of ​​the tip end space, and the area of ​​the flow path.

2. The syringe according to claim 1 , wherein an area of ​​the flow path in the holding member is smaller than an area of ​​the base end space when viewed from the axial direction of the barrel.

3. 3. The syringe according to claim 1, wherein the base end portion of the holding member has a base end surface that serves as a contact surface against which a piston inserted into the barrel from the base end side can contact, and the contact surface is configured so that the tip surface of the piston makes surface contact around the entire circumference of the barrel.

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