Syringe

Abstract

The present invention provides a syringe that captures particles within the drug while suppressing drug dispensing resistance during drug administration. [Solution] The device comprises a barrel formed in a cylindrical shape having a tip and a base, with an injection hole 64 provided at the tip for dispensing a drug to the outside; a filter 7 located inside the barrel on the base side of the injection hole; and a holding member 8 that holds the filter and has a base side portion located on the base side of the filter, wherein a flow path 81 for the drug to flow is provided at the base side portion, a base side space is provided at the base side of the filter for the drug that has flowed through the flow path to flow in, and a tip side space is provided at the tip side of the filter for the drug to flow in from the base side space through the filter, and when viewed from the axial direction of the barrel, the area of ​​the injection hole is smaller than the area of ​​the base side space, smaller than the area of ​​the tip side space, and smaller than the area of ​​the flow path.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the priority of Japanese Patent Application No. 2020 - 179783, and is incorporated herein by reference in its entirety for all purposes.

[0002] The present invention relates to a syringe provided with a filter capable of filtering particles in a drug, for example, at the time of drug administration.

Background Art

[0003] Conventionally, as a syringe for administering a drug, a cylinder including a filter body is known (Patent Document 1). A fixing member with a syringe needle attached is detachable at the tip of the cylinder. Also, a filter body that filters foreign substances and allows only the drug solution to flow is disposed inside the tip of the cylinder.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, particles may be encapsulated or formed in the drug filled in such a cylinder. The particles may be, for example, silicon oil, glass, plastic, rubber derived from the syringe, or protein aggregates, powders, etc. derived from the drug. In the above cylinder, it is conceivable to filter these particles with a filter, but there is a risk that the injection resistance at the time of drug administration may increase.

[0006] An object of the present invention is to provide a syringe that suppresses the injection resistance of a drug while capturing particles in the drug at the time of drug administration.

Means for Solving the Problems

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

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

[0009] Furthermore, in the syringe, the base end portion of the holding member is provided with a base end surface that can be contacted by a piston inserted into the barrel from the base end, and this contact surface may be configured such that the tip surface of the piston makes surface contact with the entire circumference of the barrel. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a side view of a pre-filled syringe equipped with a syringe according to this embodiment. [Figure 2] Figure 2 is a cross-sectional view along the line II-II in Figure 1. [Figure 3] Figure 3 is an enlarged cross-sectional view of the region shown as III in Figure 2. [Figure 4]Figure 4 is a schematic diagram illustrating the attachment of the filter to the syringe. [Figure 5] Figure 5 is a side view of a modified pre-filled syringe. [Figure 6] Figure 6 is an enlarged cross-sectional view of the region shown as VI in Figure 5. [Figure 7] Figure 7 is a side view of a syringe-equipped container according to a modified example. [Figure 8] Figure 8 is an enlarged cross-sectional view of the region shown as VIII in Figure 7. [Modes for carrying out 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 Figures 1 to 4.

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

[0013] Syringe 2 comprises a cylindrical barrel 6 having a tip portion 60 and a base portion 61, a filter 7 disposed inside the barrel 6, and a holding member 8 configured to hold the filter 7. Syringe 2 is also substantially cylindrical. Although syringe 2 in this embodiment has one filter 7, it may have multiple filters 7 stacked on top of each other.

[0014] Hereinafter, in pre-filled syringe 1 and syringe 2, the side where the tip portion 60 is located (the upper side in Figures 1 to 3) will be simply referred to as the "tip side," and the side where the proximal portion 61 is located (the lower side in Figures 1 to 3) will be referred to as the "proximal side." The axial direction of syringe 2 will also be simply referred to as the "axial direction."

[0015] The barrel 6 is a member for accommodating a drug therein. The barrel 6 of the present embodiment includes, in addition to a tip portion 60 and a base end portion 61, a cylindrical portion 62 that connects the tip portion 60 and the base end portion 61 (see FIG. 2). Further, the barrel 6 has a flange portion 63 that extends outward (in the radially outer 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 of a material that is, for example, transparent and can withstand the internal pressure applied when administering the 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 a COP (cyclic olefin polymer) that is a homopolymer of a cyclic olefin or a COC (cyclic olefin copolymer) that is a copolymer of a cyclic olefin and ethylene or the like. Note that the barrel 6 may be made of PP (polypropylene) or glass.

[0017] Silicon oil is applied to the inner peripheral surface of the barrel 6 (for example, the inner peripheral surface of the cylindrical portion 62) in order to suppress the sliding resistance of the piston 3 with respect to the inner peripheral surface of the barrel 6.

[0018] The tip portion 60 of the barrel 6 is provided at one end (specifically, the tip-side end) in the axial direction of the cylindrical portion 62. The tip portion 60 is provided with an injection hole 64 for injecting the drug accommodated therein to the outside. In the barrel 6 of the present embodiment, the injection hole 64 is a needle hole through which the injection needle 4 is inserted.

[0019] When the needle inserted into the injection hole 64 is, for example, 27 gauge, the inner diameter of the injection hole 64 is 0.27 mm, and the area of the injection hole 64 when viewed from the axial direction is 0.057 mm 2 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 in the direction orthogonal to the axis of the injection hole 64 is substantially constant.

[0020] The base end face 600 of the tip portion 60 is formed to close off the portion of the edge of the cylindrical portion 62 located on the tip side, excluding the dispensing hole 64. The base end face 600 extends in an inclined manner, for example, so that it is located closer to the tip as it moves in the radial direction.

[0021] The area of ​​the cylindrical portion 62 when viewed from the axial direction (the cross-sectional area of ​​the cylindrical portion 62 in the direction perpendicular to the axis) is, for example, approximately constant, specifically 12.56 mm². 2 More than 314mm 2 The following applies: The inner diameter of the cylindrical portion 62 is, for example, approximately constant, specifically between 4 mm and 20 mm.

[0022] The retaining member 8 is the member to which the filter 7 is attached. The retaining member 8 is housed inside the barrel 6 in a state of 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 retaining member 8 is made of a flexible material. The retaining member 8 in this embodiment is more flexible than the barrel 6. Specifically, the material of the retaining member 8 is, for example, a resin, rubber, or elastomer that is softer than the material of the barrel 6. The flexibility between the barrel 6 and the retaining member 8 can be confirmed, for example, by measuring the durometer hardness. By forming the retaining member 8 from such a material, the flexibility of the retaining member 8 relative to the barrel 6 can be ensured, thereby preventing cracks in the barrel 6.

[0024] The retaining member 8 includes a proximal portion 80 positioned on the proximal side of the filter 7. In this embodiment, the retaining member 8 consists only of the proximal portion 80. The proximal portion 80 of the retaining member 8 is provided with a flow path 81 through which the drug flows from the proximal side to the tip side.

[0025] The base end portion 80 of the retaining member 8 is provided with a contact surface 800 as the base end surface 800, which can be contacted by the piston 3 inserted into the barrel 6 from the base end. The base end portion 80 has a cylindrical shape with its tip closed by a disc having a through hole in the center.

[0026] The contact surface 800 of the base end portion 80 has a shape that corresponds to the tip surface 33 of the piston 3. Furthermore, the contact surface 800 is configured such that the tip surface 33 of the piston 3 makes surface contact with the barrel 6 over its entire circumference.

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

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

[0029] The connecting contact surface 803 is a surface that extends along the axial direction. For example, the central part of the connecting contact surface 803 in the axial direction is concave toward the radially outward direction.

[0030] The base end portion 80 of this embodiment includes a mounting portion 82 to which the filter 7 is attached, and a leg portion 83 extending from the mounting portion 82. In this base end portion 80, the mounting portion 82 is provided on the tip side, and the leg portion 83 is located on the base end side.

[0031] The flow path 81 is provided at the mounting 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 the direction perpendicular to the axis) is constant. Also, the area of ​​the flow path 81 when viewed from the axial direction is 0.64 mm². 2 More than 1.33mm 2The following applies: The inner diameter of the flow path 81 in this embodiment is constant. Furthermore, 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, specifically cylindrical, but may also be rectangular.

[0032] The mounting portion 82 has a shape in which its outer circumference protrudes toward the tip. The outer surface of the mounting portion 82 in this embodiment is slightly separated from the inner surface of the barrel 6 (specifically, the inner surface of the cylindrical 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 a mounting outer circumference portion 820 that constitutes the outer circumference, and a mounting inner circumference portion 821 that is located inward in diameter from the mounting outer circumference portion 820 and defines the flow path 81.

[0033] Furthermore, at the mounting portion 82, the outer peripheral tip surface 822, which is the tip surface of the mounting outer peripheral portion 820, is located closer to the tip than the inner peripheral tip surface 823, which is the tip surface of the mounting inner peripheral portion 821. In other words, the tip surface of the mounting portion 82 is concave in the center in the circumferential direction. The mounting outer peripheral portion 820 has a shoulder portion 824 as the outer peripheral portion on the tip side.

[0034] The leg portion 83 has a shape in which its outer circumference protrudes toward the base end. The base end surface 830 of the leg portion 83 constitutes the contact surface 800 of the base end portion 80. The outer circumferential surface of the leg portion 83 is in surface contact with the inner circumferential surface of the barrel 6 (specifically, the inner circumferential surface of the cylindrical portion 62 of the barrel 6). In this way, the outer circumferential surface of the leg portion 83 is in close contact with the inner circumferential surface of the barrel 6, so that the drug is reliably filtered through the flow path 81 of the holding member 8 by the filter 7.

[0035] Filter 7 is a filter for filtering out the drug. Filter 7 is located inside the barrel 6, closer to the base end than the dispensing hole 64.

[0036] The proximal end of the filter 7 is provided with a proximal space 72 into which the drug that has flowed through the channel 81 flows. The tip end of the filter 7 is provided with a tip end space 71 into which the drug flows from the proximal space 72 through the filter 7. The filtration area of ​​the filter 7 is the area of ​​the tip end edge of the proximal space 72 and the area of ​​the proximal end edge of the tip end space 71. The area of ​​the tip end edge of the proximal space 72 is, for example, equal to the area of ​​the proximal end edge of the tip end space 71.

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

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

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

[0040] As shown in Figure 4, in the state before welding the filter 7, the base end portion 80 (for example, the mounting outer circumference 820) is provided with a protruding portion 825 that extends toward the tip. When the filter 7 is welded, the protruding portion 825 melts and spreads, so in the state after welding the filter 7, the tip surface 804 of the base end portion 80 becomes a substantially flat surface.

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

[0042] Furthermore, the tip-side space 71 has a shape in which, for example, the area when viewed from the cylindrical direction from the base end to the tip end (cross-sectional area in the direction perpendicular to the axis) decreases, that is, it has a tapered shape in which the area when viewed from the cylindrical direction (cross-sectional area in the direction perpendicular to the axis) decreases towards the tip end. In this embodiment, the tip-side space 71 is substantially cylindrical. This tip-side space 71 has a shape in which, for example, the inner diameter decreases from the base end to the tip end, that is, it has a tapered shape in which the inner diameter decreases towards the tip end. In addition, 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 is smaller towards the outer circumference. 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 is easy to move from the outer circumference to the cylindrical axis in the circumferential direction, thereby reducing dispensing resistance. The tip-side space 71 may also be rectangular.

[0043] The base portion of the tip-side space 71, that is, the portion of the tip-side 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 holding member 8.

[0044] The base end space 72 is defined by the filter 7 (specifically, the base end side of the filter 7) and the tip surface 804 of the base end portion 80 (specifically, the inner tip surface 823 of the mounting inner circumference portion 821 and the mounting inner circumference surface 826, which is the inner circumference surface of the mounting outer circumference portion 820). Furthermore, the base end space 72 is formed by the inner tip surface 823 of the mounting inner circumference portion 821 being recessed towards the base end than the outer tip surface 822 of the mounting outer circumference portion 820, that is, by the tip surface of the mounting portion 82 being recessed towards the base end.

[0045] Furthermore, the base end space 72 is continuous with the flow path 81. In addition, the base end space 72 has a shape in which the surface area when viewed from the axial direction increases from the base end to the tip end, that is, a tapered shape in which the area when viewed from the axial direction increases towards the tip end. The base end space 72 in this embodiment is substantially cylindrical. This base end space 72 has a shape in which the inner diameter increases from the base end to the tip end, that is, a tapered shape in which the inner diameter increases towards the tip end. The inclination angle with respect to the axial direction of the mounting inner surface 826 of the mounting outer circumference 820 that defines the base end space 72 is smaller than the inclination angle with respect to the axial direction of the base end surface 600 of the tip portion 60 that defines the tip end space 71. Note that the base end space 72 may also be rectangular.

[0046] In the syringe 2 described above, the barrel 6 and the proximal end portion 80 of the retaining member 8 hold the filter 7. Specifically, the proximal end face 600 of the tip portion 60 of the barrel 6 (specifically, the proximal end edge 601 of the proximal end face 600) and the shoulder portion 824 of the proximal end portion 80 hold the filter 7 in the axial direction. As a result, even if pressure is applied to the filter 7 when administering the drug solution, the attachment of the filter 7 to the proximal end portion 80 is less likely to come loose.

[0047] From the proximal end to the tip end, the flow path 81, the proximal end space 72, the tip end space 71, and the injection port 64 are arranged in that order. In syringe 2 of this embodiment, the central axis of the flow path 81, the central axis of the proximal end space 72, and the central axis of the tip end space 71 all coincide with the central axis of the injection port 64. As a result, when administering a drug, the flow of the drug from the flow path 81 to the injection port 64 is smooth.

[0048] The axial dimension L81 of the flow path 81 is larger than the axial dimension L72 of the base end space 72. Also, the axial dimension L71 of the tip end space 71 (specifically, the dimension of the tip end space 71 along its central axis) is larger than the axial dimension L72 of the base end space 72.

[0049] When viewed from the axial direction, the area of ​​the dispensing hole 64 is smaller than the area of ​​the base-side space 72, smaller than the area of ​​the tip-side space 71, and smaller than the area of ​​the flow path 81. Specifically, the area of ​​the dispensing hole 64 is smaller than the area of ​​any part of the base-side space 72 in the axial direction, smaller than the area of ​​any part of the tip-side space 71 in the axial direction, and smaller than the area of ​​any part of the flow path 81 in the axial direction.

[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 part of the base end space 72 in the axial direction.

[0051] Specifically, the inner diameter R64 of the dispensing hole 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. Furthermore, the inner diameter R81 of the flow path 81 is smaller than the inner diameter R72 of the base end space 72.

[0052] Regarding these dimensional relationships, experiments were conducted using a barrel 6 with an inner diameter R64 of the dispensing hole 64 of 0.27 mm and 0.21 mm, and a retaining member 8 with 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 investigate 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 sliding load was observed. When the inner diameter R72 of the base end space 72 was 2.1 mm or 3.6 mm, no significant change in 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 sliding load was observed.

[0054] For example, the inner diameter R81 of the flow path 81 is preferably greater than 1 times and 5 times or less the inner diameter R64 of the dispensing hole 64, and preferably between 1.1 times and 4.3 times the inner diameter R64 of the dispensing hole 64. If the inner diameter R64 of the dispensing 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, or 0.9 mm. Also, for example, the inner diameter R72 of the base end space 72 (filtration area of ​​the filter 7) is preferably between 5 times and 20 times the inner diameter R64 of the dispensing hole 64, and preferably between 7 times and 18 times the inner diameter R64 of the dispensing hole 64. If the inner diameter R64 of the dispensing 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 and R71 of the proximal space 72 and the tip space 71 are within this range, it is possible to reduce dispensing resistance while ensuring a sufficient filtration area when administering the drug.

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

[0056] The piston 3 is a component that is operated when dispensing the drug from the barrel 6. The piston 3 in this embodiment has an axial rod portion 30, a gasket 31 attached to one end of the rod portion 30 in the longitudinal direction and in close contact with the entire inner circumference of the cylindrical portion 62 of the barrel 6, and an operating portion 32 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 from the tip surface of the gasket 31. Specifically, when administering the drug, the tip surface 33 contacts at least the base end contact surface 801 of the base end portion 80 of the retaining member 8, and more specifically, in addition to the base end contact surface 801, it also contacts the connecting contact surface 803.

[0058] Furthermore, the piston 3 has a contact portion 34 that is in close contact with the inner circumferential 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 abuts against the base end contact surface 801, and the tip surface of the protruding portion 35 abuts against the tip end contact surface 802. In addition, the outer circumferential surface of the protruding portion 35 is in close contact with the connecting contact surface 803.

[0059] The injection needle 4 is a component used to administer the drug contained in the barrel 6 to the patient. The tip of the injection needle 4 is covered by a cap 5.

[0060] With the syringe 2 described above, even if particles are present in the drug contained in the barrel 6, the particles can be captured by the filter 7 when the drug is administered. Furthermore, since the drug flows through the channel 81, the proximal end space 72, and the tip side space 71, which have a larger area (e.g., inner diameter) than the injection hole 64, and is injected from the injection hole 64, resistance when flowing through the channel 81, the proximal end space 72, and the tip side space 71 can be suppressed, resulting in reduced drug injection resistance.

[0061] In the syringe 2 of this embodiment, the area (e.g., inner diameter) of the flow path 81 is reduced, and the area (e.g., inner diameter) of the proximal end space 72 is increased. This makes it possible to reduce the amount of drug remaining in the flow path 81 while ensuring the contact area of ​​the drug with the filter 7 (filtration area by the filter 7), thereby suppressing the amount of residual liquid while suppressing dispensing 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 makes full circumferential contact with the contact surface 800 of the retaining member 8, thereby suppressing residual liquid between the piston 3 and the retaining member 8, and thus suppressing the amount of residual drug in the barrel 6.

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

[0064] The configuration of the retaining member 8 may differ 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 connecting contact surface 803 in the above embodiment extended along the axial direction, it may also include portions that extend in a direction inclined with respect to the axial direction. More specifically, as shown in Figures 5 and 6, the connecting contact surface 803 may include a first connecting contact surface 803a which is substantially perpendicular to the axial direction, and a second connecting contact surface 803b, 803c which is a pair of surfaces extending along the axial direction from both ends of the first connecting contact surface 803a.

[0066] Specifically, although the base end contact surface 801 in the above embodiment was a surface substantially perpendicular to the axial direction, it may also include portions inclined at angles other than perpendicular to the axial direction. More specifically, as shown in Figures 7 and 8, the base end contact surface 801 may include a first base end contact surface 801a, which is a surface substantially perpendicular to the axial direction, and a second base end contact surface 801b, which extends further inward from the radially inward edge of the first base end contact surface 801a and is inclined such that the portion on the radially inward side is located closer to the tip.

[0067] Even with this configuration, the tip surface 33 of the piston 3 moves until it makes full surface contact with the contact surface 800 of the retaining member 8 in the circumferential direction, thereby suppressing residual liquid between the piston 3 and the retaining member 8, and thus suppressing the amount of residual liquid of the drug in the barrel 6.

[0068] In the above embodiment, the retaining member 8 was composed of a base end portion 80, but the tip end portion, which is positioned further forward than the filter 7, may be included either integrally with or separately 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 was 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 above embodiment of the retaining member 8, the contact surface 800 of the base end portion 80 was configured such that the tip surface 33 of the piston 3 made surface contact with the barrel 6 over its entire circumference. However, it may also be configured so that it makes 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 intermittent recesses or protrusions in the circumferential direction on the base end contact surface 801 of the contact surface 800 of the base end portion 80.

[0071] In the syringe 2 of the above embodiment, the tip-side space 71 had a tapered shape with a smaller inner diameter towards the tip, but it may also have other shapes, such as a shape with a uniform inner diameter. In this case, the base-side end face 600 may extend in a direction perpendicular to the axial direction, for example.

[0072] The base-side space 72 had a tapered shape with a smaller inner diameter towards the tip, but it may also have other shapes, such as a uniform inner diameter.

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

[0074] Furthermore, the axial dimension of the tip-side space 71 may be less than or equal to the axial dimension of the base-side space 72. In this case, for example, the inclination angle of the base-side end face 600 of the tip portion 60 of the barrel 6 with respect to the cylindrical axis may be reduced, and the base-side portion 80 of the retaining member 8 may be positioned to abut against the base-side end face 600, or the axial dimension of the base-side portion 80 of the retaining member 8 may be increased.

[0075] According to the present invention, it is possible to provide a syringe that suppresses drug dispensing resistance while capturing particles within the drug during drug administration.

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

[0077] With this configuration, even if particles are present in the drug contained in the barrel, the particles can be captured by the filter when the drug is administered. Furthermore, since the drug flows through a channel, a proximal space, and a tip space that have a larger area than the dispensing hole before being dispensed from the dispensing hole, resistance during flow through the channel, proximal space, and tip space can be suppressed, resulting in reduced drug dispensing resistance.

[0078] Furthermore, in the syringe, when viewed from the axial direction of the barrel, the area of ​​the flow path in the holding member may be smaller than the 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 is reduced while ensuring the area in contact with the filter (filtration area), and the amount of residual liquid is reduced while suppressing dispensing resistance.

[0080] Furthermore, in the syringe, the base end portion of the holding member is provided with a base end surface that can be contacted by a piston inserted into the barrel from the base end, and this contact surface may be configured such that the tip surface of the piston makes surface contact with the entire circumference of the barrel.

[0081] With this configuration, when administering the drug, the tip surface of the piston moves until it makes full surface contact with the contact surface of the retaining member in the circumferential direction, thereby suppressing residual liquid between the piston and the retaining member and reducing the amount of residual drug 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 section, 31...Gasket, 32...Operating section, 33...Contact surface (tip surface), 34...Fitting section, 35...Protruding section, 60...Tip section, 61...Base end section, 62...Cylindrical section, 63...Flange section, 64...Discharge hole, 65...Inner circumferential surface, 71...Tip side space, 72...Base end side space, 80...Base end section, 81...Flow path, 82...Mounting section, 83...Leg section, 600...Base end side end surface 601... Base end edge, 800... Contact surface (base end face), 801... Base end contact surface, 801a... First base end contact surface, 801b... Second base end contact surface, 802... Tip end contact surface, 803... Connection contact surface, 803a... First connection contact surface, 803b... Second connection contact surface, 803c... Second connection contact surface, 804... Tip surface, 820... Mounting outer circumference, 821... Mounting inner circumference, 822... Outer circumference tip surface, 823... Inner circumference tip surface, 824... Shoulder portion, 825... Protrusion, 826... Mounting inner circumference surface, 830... Base end surface

Claims

1. A syringe for administering medication, A barrel formed in a cylindrical shape having a tip and a base, with an injection hole provided at the tip for dispensing the drug contained inside to the outside, A filter positioned inside the barrel on the base end side of the pouring hole, The barrel comprises a retaining member configured to hold the filter, which is disposed inside the barrel, and having a base end portion that is positioned on the base end side of the filter, The base end portion of the holding member is provided with a flow path through which the drug flows from the base end to the tip end. A base-end space is provided at the base end of the filter, into which the drug that has flowed through the channel flows. The tip side of the filter is provided with a tip-side space through which the drug flows in from the base-side space via the filter. A syringe in which, when viewed from the axial direction of the barrel, the area of ​​the dispensing 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.

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

3. The syringe according to claim 1 or 2, wherein the base end portion of the retaining member is provided with a base end surface that can contact a piston inserted into the barrel from the base end, and the contact surface is configured such that the tip surface of the piston makes surface contact with the barrel over its entire circumference.

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