Drug administration device

Abstract

To provide a liquid medicine administration instrument with a double-ended needle.SOLUTION: A liquid medicine administration instrument 10 includes a syringe 302 and a double-ended needle 402. The syringe has a barrel body 308 in which a medicine chamber 322 is formed, and a nozzle part 306 in which an insertion hole 318 is formed. The double-ended needle has a first needle portion 406 facing a puncture target B, and a second needle portion 408 facing the syringe. A receiving port is formed in the second needle portion which receives liquid medicine M in a medicine chamber. When the first needle portion punctures the puncture target, the second needle portion is inserted into the insertion hole. At this time, the receiving port is located between the base end of the nozzle part and a gasket 342 inserted into the barrel body.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a medicinal liquid administration device configured to administer, to a patient, a predetermined amount less than the entire amount of a medicinal liquid contained in a medicinal liquid chamber. [Background Art]

[0002] Portable medicinal liquid administration devices that administer a medicinal liquid to a patient via a needle punctured into the patient's skin are known. In the medicinal liquid administration device described in Patent Document 1, a cap is attached to a distal end of a cylindrical main body. Inside the main body, a cartridge filled with a medicinal liquid and a needle holder holding a needle are accommodated. The needle has a first needle portion and a second needle portion. The first needle portion and the second needle portion respectively protrude from the needle holder in directions opposite to each other. That is, the needle is a so-called double-ended needle.

[0003] When administering a medicinal liquid to a patient using the medicinal liquid administration device, a user rotates the cap relative to the main body and removes the cap from the main body. At this time, the needle and the needle holder are biased toward the cartridge by an elastic force of a spring inside the cap. Accordingly, the needle holder moves toward the cartridge. As a result, an end portion of the second needle portion is inserted into the cartridge. This brings the medicinal liquid in the cartridge into a state where it can be administered to the patient via the needle. [Prior Art Literature] [Patent Literature]

[0004] [Patent Document 1] Japanese National Publication of International Patent Application No. 2018-535042 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] In containers where the drug solution is pre-filled in the chamber, air may be present in the drug solution. Furthermore, when administering the drug solution to a patient, the first needle that is inserted into the patient is not always pointing vertically downwards. For example, depending on the puncture site, the user may point the first needle vertically upwards or horizontally. If the first needle is pointed vertically upwards, horizontally, or somewhere between vertically upwards and horizontally while air is present in the drug solution, there is a concern that the drug solution and air may flow into the lumen of the second needle. If such a situation occurs, it becomes difficult to administer the prescribed amount of drug solution to the patient.

[0006] The present invention aims to solve the problems described above. [Means for solving the problem]

[0007] (1) According to one embodiment of the present invention, a hollow cylindrical housing, a barrel, a chamber formed in the barrel and filled with a drug solution, and a gasket that is liquid-tight and slidable inside the barrel, wherein the barrel has a barrel body housing the gasket, a cylindrical nozzle portion protruding from the barrel body toward the tip, and a sealing member that liquid-tightly seals the tip opening of the nozzle portion, a syringe housed in the housing so as to be movable relative to the housing toward the tip, a plunger that moves relative to the housing toward the tip to push the gasket toward the tip, a first needle portion protruding toward the tip to puncture the target, and a second needle portion protruding toward the proximal end toward the syringe, wherein the second needle portion is located inside the housing A drug administration device is provided, comprising: a double-ended needle positioned such that the first lumen of the first needle portion and the second lumen of the second needle portion are in communication with each other; and a movement stopper that stops the movement of the plunger toward the tip so that the gasket stops at a completed administration position where the gasket is separated from the tip of the barrel body toward the base end, wherein the second needle portion has a receiving port that communicates with the second lumen and receives the drug solution in the drug chamber, and when the syringe moves relative to the housing toward the tip, the second needle portion is inserted into the nozzle portion and the connection of the second needle portion to the barrel is completed, the receiving port of the second needle portion is located between the base end of the nozzle portion and the gasket.

[0008] The specific gravity of air is lower than that of the drug solution. Therefore, when air is mixed in with the drug solution in the drug chamber, for example, if the first needle is oriented vertically upward or horizontally, the air will concentrate in the insertion hole, which is inside the nozzle. In this invention, the receiving port for the drug solution in the second needle is located between the base end of the nozzle and the gasket. In this configuration, when the drug solution in the drug chamber flows into the second lumen through the receiving port, it is difficult for the air inside the nozzle (inside the insertion hole), which is located on the tip side of the drug chamber, to move into the drug chamber and flow into the second lumen through the receiving port. This allows a specified amount of drug solution to be administered to the target of puncture.

[0009] (2) In item (1) above, the barrel body has a body portion and a shoulder portion interposed between the body portion and the nozzle portion, which decreases in diameter as it approaches the nozzle portion, and it is preferable that the receiving port in the second needle portion is located inside the shoulder portion or inside the body portion.

[0010] As described above, when the first needle is oriented vertically upward or horizontally, air mixed in the drug solution concentrates in the insertion hole, which is inside the nozzle. On the other hand, in this configuration, the receiving port is located in the drug chamber. Therefore, it becomes even more difficult for air in the insertion hole to flow into the second lumen through the receiving port. Consequently, it becomes even easier to administer the prescribed amount of drug solution to the target of puncture.

[0011] (3) In item (1) or (2) above, the movement stopping portion includes a ring body that passes through the plunger and is movable relative to the plunger, the plunger has a projection at its tip that protrudes from the side wall of the plunger in a direction perpendicular to the axial direction of the plunger, and when the plunger moves in the direction of the tip, it is preferable that the projection comes into contact with the ring body and stops the movement in the direction of the tip.

[0012] In this case, the ring body obstructs the movement of the plunger, allowing the plunger to be stopped before the entire amount of the drug solution in the chamber is administered to the target of puncture. In other words, the plunger can be stopped when the predetermined amount of drug solution in the chamber has been administered to the target of puncture, thereby ending the administration of the drug solution to the target of puncture.

[0013] (4) In any one of the above items (1) to (3), it is preferable that the syringe holder is arranged on the outer circumference of the syringe to hold the syringe and is movable inside the housing, and that the syringe holder moves integrally with the syringe toward the tip while being guided by the housing.

[0014] For example, when forming a guide hole in a syringe, if the guide hole is positioned to overlap with the drug chamber, there is a concern that the drug solution may leak from the guide hole. Therefore, it is not possible to position the guide hole to overlap with the drug chamber. Thus, when providing a guide hole in a syringe, there are limitations on where the guide hole can be formed. In contrast, since a syringe holder is not filled with drug solution, there are no restrictions on forming guide holes, slits, or openings in the syringe holder. Thus, syringe holders have a greater degree of freedom in shape compared to syringes.

[0015] In addition, for example, by providing a first guide section on the housing and a second guide section on the syringe holder, and guiding the second guide section with the first guide section, the syringe holder and the syringe held in the syringe holder can be moved integrally. Thus, with this configuration, it is easy to move the syringe within the housing.

[0016] (5) In item (4) above, it is preferable that the housing has a first guide portion and the syringe holder has a second guide portion, where one of the first guide portion or the second guide portion is a guide hole, and the other of the first guide portion or the second guide portion is a guide projection movably inserted into the guide hole, and the movement of the syringe holder and the syringe stops when the guide projection reaches the tip end of the guide hole.

[0017] This determines the relative stopping position of the syringe holder and syringe housing. Since the plunger moves in this position, a specified amount of medication can be precisely dispensed from the chamber. In other words, the amount of medication administered to the target of puncture can be precisely controlled.

[0018] (6) In the above item (4) or (5), it is preferable that a holder lock for positioning the syringe holder is provided, the holder lock has a first engaging portion, the syringe holder has a second engaging portion, in an initial state, the first engaging portion and the second engaging portion engage with each other to position the syringe holder within the housing, and when the engagement between the first engaging portion and the second engaging portion is released, the syringe holder and the syringe can integrally move within the housing.

[0019] According to this configuration, movement of the syringe holder and the syringe can be prevented before the first needle portion punctures a puncture target.

Effects of the Invention

[0020] According to the present invention, even when air is mixed in the drug solution in the initial state, air is prevented from being entrained in the drug solution administered to a puncture target via the double-ended needle. Therefore, a prescribed amount of the drug solution can be administered to the puncture target.

Brief Description of Drawings

[0021] [Figure 1] FIG. 1 is an exploded perspective view of a drug solution administration device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view along the axial direction of the drug solution administration device. [Figure 3] FIG. 3 is a cross-sectional view along the axial direction of the drug solution administration device in a posture obtained by rotating the drug solution administration device by 90° from FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view of the drug solution administration device showing a state where the tip of the double-ended needle punctures a patient's body when the axial direction of the drug solution administration device extends along the horizontal direction. [Figure 5] FIG. 5 is a cross-sectional view of the drug solution administration device showing a state where the drug solution is being administered to the patient subsequent to the state shown in FIG. 4. [Figure 6] FIG. 6 is a cross-sectional view of the drug solution administration device showing a state where the drug solution is being administered to the patient in a posture obtained by rotating the drug solution administration device by 90° from FIG. 5. [Figure 7] Fig. 7 is a cross-sectional view of the medicinal solution administration device when the tip of the double-ended needle is punctured into the patient's body in a case where the tip of the medicinal solution administration device faces upward in the gravity horizontal direction. [Figure 8] Fig. 8 is a cross-sectional view of the medicinal solution administration device showing a state where the tip of the double-ended needle has been withdrawn from the patient's body following the state shown in Figs. 5 and 6. Mode for Carrying Out the Invention

[0022] In the following embodiment, the patient's body B (see Fig. 5) is exemplified as the puncture target. A user is typically a patient, but is not particularly limited to a patient. The distal direction is the direction facing the patient's body B, which is the puncture target. The proximal direction is the direction opposite to the distal direction. The axial direction is the direction connecting the distal end and the proximal end. In addition, the "initial state" refers to a state of the medicinal solution administration device before a puncture operation is performed by a user.

[0023] Fig. 1 is an exploded perspective view of the medicinal solution administration device 10 according to the present embodiment. The medicinal solution administration device 10 includes a housing, a needle cover, a syringe unit, a needle assembly, and a plunger.

[0024] The material of the housing 100 is, for example, a resin material. The housing 100 is formed into a hollow cylindrical shape having a predetermined length in the axial direction. Both ends (distal end and proximal end) of the housing 100 in the axial direction are open ends. When the housing 100 is viewed from the axial direction, the housing 100 has a substantially elliptical shape. The needle cover 200 is inserted through the first opening 102, which is the distal opening of the housing 100. The second opening 104, which is the proximal opening of the housing 100, is closed by an end cap 140.

[0025] The housing 100 is formed with a pair of first connection holes 108, a pair of second connection holes 110, and four holes 112. The pair of first connection holes 108, the pair of second connection holes 110, and the four holes 112 penetrate along the thickness direction from the inner wall to the outer wall of the housing 100.

[0026] The second connecting hole 110 is formed in a location closer to the second opening 104 than the first connecting hole 108. The four holes 112 are formed in locations closer to the second opening 104 than the second connecting hole 110. Two of the four holes 112 and the remaining two of the four holes 112 are arranged symmetrically with respect to the axial direction of the housing 100 as the line of symmetry.

[0027] Figure 2 is a cross-sectional view of the drug dispensing device 10 along its axial direction. Figure 3 is a cross-sectional view of the drug dispensing device 10 along its axial direction, rotated 90° from the position shown in Figure 2. As shown in Figures 2 and 3, a cylindrical needle holder 118 is provided inside the housing 100 near the first opening 102. The needle holder 118 is spaced at a predetermined distance from the inner surface of the side of the housing 100 and is connected to the inner surface of the side of the housing 100 via a pair of support parts 120. This spacing creates an insertion opening (not shown) between the needle holder 118 and the inner wall of the housing 100.

[0028] As shown in Figure 2, multiple internal guide grooves 116 are formed as first guide sections on the inner surface of the side of the housing 100, near the second opening 104. The internal guide grooves 116 extend from the second opening 104 of the housing 100 toward the first opening 102. The leading end of the internal guide grooves 116 is located closer to the first opening 102 than to the hole 112.

[0029] Inside the housing 100, a pair of stopper ribs 124 are provided at a position closer to the second opening 104 from the needle holding portion 118. The stopper ribs 124 protrude radially inward from the inner circumferential wall of the housing 100. The stopper ribs 124 extend axially for a predetermined length.

[0030] The end cap 140 has a lid portion 142, a large-diameter cylindrical portion 144, a small-diameter cylindrical portion 146, and a retaining shaft portion 148. The lid portion 142 is disc-shaped and closes the second opening 104 of the housing 100. The large-diameter cylindrical portion 144, the small-diameter cylindrical portion 146, and the retaining shaft portion 148 are arranged concentrically on the inner surface (tip end face) of the lid portion 142 and extend toward the tip. The small-diameter cylindrical portion 146 is located radially inward of the large-diameter cylindrical portion 144, and the retaining shaft portion 148 is located radially inward of the small-diameter cylindrical portion 146. The axial length of the large-diameter cylindrical portion 144 is greater than the axial length of the small-diameter cylindrical portion 146. The axial length of the retaining shaft portion 148 is greater than the axial length of the large-diameter cylindrical portion 144.

[0031] A pair of connecting protrusions 150 are symmetrically provided at the tip of the outer surface of the peripheral wall of the large-diameter cylindrical portion 144. The connecting protrusions 150 engage with a second connecting hole 110 formed in the housing 100. This connects the end cap 140 to the housing 100. A pair of cap-side claws 152 are symmetrically provided at the tip of the outer surface of the peripheral wall of the small-diameter cylindrical portion 146.

[0032] As described above, the retaining shaft portion 148 is positioned on the axis of the housing 100 and extends to near the axial center of the housing 100. The plunger 500 is fitted over the retaining shaft portion 148 via the injection spring 160. The retaining shaft portion 148, the injection spring 160, and the tip of the plunger 500 are inserted into the syringe 302 that constitutes the syringe unit 300.

[0033] The needle cover 200 is formed in a hollow cylindrical shape. At least a portion of the needle cover 200 is inserted into the housing 100 through the first opening 102 of the housing 100. The needle cover 200 is axially movable relative to the housing 100. In the initial state, the needle cover 200 covers at least the first needle portion 406 of the double-ended needle 402 that constitutes the needle assembly 400.

[0034] The needle cover 200 comprises a tip cover portion 202 provided at the tip, a cylindrical cover portion 204 extending from the tip cover portion 202 toward the base end, and a pair of extension portions 206 (see Figures 1 and 3) extending from the base end of the cylindrical cover portion 204.

[0035] A needle hole 208 is formed in the center of the tip of the tip cover portion 202, penetrating in the axial direction. As the needle cover 200 is pressed against the user's body B (see Figure 4) during the puncture operation, the needle cover 200 moves relative to the housing 100 in the proximal direction. As a result, the needle assembly 400 moves relative to the needle cover 200 in the tip direction. Consequently, the first needle portion 406 of the double-ended needle 402 is inserted through the needle hole 208 and protrudes from the needle cover 200 in the tip direction.

[0036] The cylindrical cover portion 204 has a pair of slits 210 extending from the base end toward the tip. When the cylindrical cover portion 204 is inserted into the housing 100 through the first opening 102 of the housing 100, the cylindrical cover portion 204 passes through the insertion opening between the inner surface of the side wall of the housing 100 and the needle holding portion 118.

[0037] The extension portion 206 extends from the base end of the cylindrical cover portion 204 toward the base end. When the needle cover 200 moves relative to the housing 100 toward the base end, the base end of the extension portion 206 comes into contact with the tip of the lock sleeve 640, which will be described later. In this state, the extension portion 206 pushes the lock sleeve 640 toward the base end.

[0038] The syringe unit 300 includes a syringe 302 and a syringe holder 350. The syringe holder 350 covers the outside of the syringe 302 and holds it in place. The syringe unit 300 is housed inside the hollow interior of the holder lock 700. As will be described later, the syringe unit 300 is movable towards the tip inside the hollow interior of the holder lock 700. Here, the holder lock 700 is housed inside the housing 100. Therefore, the syringe 302 and the syringe holder 350 move together as a single unit inside the housing 100.

[0039] Syringe 302 has a hollow cylindrical barrel 304. The barrel 304 has a nozzle portion 306 and a barrel body 308. The barrel body 308 has a shoulder portion 310 and a barrel body portion 312 (body portion). The barrel 304 further has a flange portion 314 provided at the base end of the barrel body portion 312.

[0040] The nozzle portion 306 extends from the tip of the shoulder portion 310 toward the tip. The nozzle portion 306 has a tip opening 316 that opens at the tip of the nozzle portion 306, an insertion hole 318, and a base end opening 320 that opens at the base end of the nozzle portion 306. The insertion hole 318 is formed from the tip opening 316 to the base end opening 320. The diameter of the insertion hole 318 (the inner diameter of the nozzle portion 306) is constant.

[0041] The shoulder portion 310 is the part interposed between the nozzle portion 306 and the barrel body portion 312. The hollow interior of the shoulder portion 310 and the barrel body portion 312 is a chamber 322 containing the chemical solution M. The chamber 322 communicates with the insertion hole 318 via the base end opening 320. The inner and outer diameters of the shoulder portion 310 taper as they move from the barrel body portion 312 towards the nozzle portion 306. In contrast, the inner and outer diameters of the barrel body portion 312 remain constant. The inner and outer diameters of the barrel body portion 312 are larger than the inner and outer diameters of the nozzle portion 306, respectively.

[0042] The flange portion 314 is provided at the base end of the barrel body 308. The outer diameter of the flange portion 314 is larger than the outer diameter of the barrel body 312. Thus, the flange portion 314 is a part that protrudes radially outward from the base end of the barrel body 308.

[0043] The syringe 302 further has a cap 330. The cap 330 is fitted to the outside of the nozzle portion 306 and covers the nozzle portion 306. An insertion hole 332 is formed at the tip of the cap 330. The insertion hole 332 overlaps with a tip opening 316 formed in the nozzle portion 306 of the barrel 304. Here, a sealing member 340 is provided inside the cap 330. The sealing member 340 is located between the insertion hole 332 and the tip opening 316. The tip opening 316 is liquid-tightly sealed by the sealing member 340. That is, in the initial state, the sealing member 340 prevents the drug solution M in the chamber 322 of the barrel 304 from leaking through the tip opening 316.

[0044] The syringe 302 further includes a gasket 342. The gasket 342 is inserted into the barrel body 312. A liquid-tight seal is maintained between the inner circumferential wall of the barrel body 312 and the side circumferential wall of the gasket 342. The gasket 342 is slidable within the barrel body 312 when pressed by the plunger 500. The sliding direction of the gasket 342 is from the base end to the tip end of the barrel body 312.

[0045] The syringe holder 350 has a cylindrical holder body 352 and a flange housing 356 provided at the base end of the holder body 352.

[0046] The holder body 352 extends along the axial direction. The barrel 304 is housed inside the holder body 352. A sufficient clearance is formed between the holder body 352 and the barrel body 312.

[0047] A pair of holder-side ribs 358 (see Figures 1 and 2) are provided on the outer circumferential surface of the holder body 352. The holder-side ribs 358 protrude radially outward from the outer circumferential surface of the holder body 352 and extend along the axial direction. The pair of holder-side ribs 358 are arranged symmetrically with respect to the axis of the syringe holder 350.

[0048] The holder body 352 has a pair of first claw holes 360 and a pair of second claw holes 362 (see Figures 1 and 3). The pair of first claw holes 360 are second engagement portions and are arranged symmetrically. The pair of second claw holes 362 are also arranged symmetrically. The pair of first claw holes 360 are closer to the tip of the holder body 352 than the pair of second claw holes 362.

[0049] The flange housing portion 356 has a substantially elliptical shape corresponding to the flange portion 314 of the syringe 302. The flange portion 314 is housed in the flange housing portion 356. With this housing, the syringe 302 is held and positioned in relation to the syringe holder 350.

[0050] The flange housing portion 356 has six external guide ribs 370 (see Figures 1 and 2) projecting radially outward as a second guide portion. The six external guide ribs 370 are each inserted into six internal guide grooves 116. The external guide ribs 370 are slidable along the internal guide grooves 116. The external guide ribs 370 together with the internal guide grooves 116 constitute a stopper portion. Thus, in this embodiment, the first guide portion is a guide hole, and the second guide portion is a guide projection. However, conversely, the first guide portion may be a guide projection, and the second guide portion may be a guide hole. Even if guide holes are formed in the syringe holder 350, there is no concern that the drug solution M will leak from the drug chamber 322.

[0051] The cylindrical holder lock 700 is positioned and fixed within the housing 100. Specifically, a pair of external engaging claws 704 are symmetrically provided on the outer surface of the peripheral wall of the holder lock 700. When the tip surface of the holder lock 700 is in contact with the base end surface of the stopper rib 124 inside the housing 100 (see Figure 3), the external engaging claws 704 engage with the first connecting hole 108, as shown in Figure 2. The contact of the tip surface of the holder lock 700 with the base end surface of the stopper rib 124 prevents the holder lock 700 from moving in the tip direction. The engagement of the external engaging claws 704 with the first connecting hole 108 prevents the syringe unit 300 from moving in the base direction.

[0052] A pair of flexible arm portions 708 (see Figure 1) are symmetrically provided on the peripheral wall of the holder lock 700. An inner claw 710 (see Figure 3) is provided on the inner surface of each of the pair of flexible arm portions 708 as a first engaging portion. In the initial state, the inner claw 710 is detachably engaged with a first claw hole 360 ​​formed in the syringe holder 350. In the puncture state, the inner claw 710 engages with a second claw hole 362 formed in the syringe holder 350 (see Figure 6).

[0053] As described above, the syringe unit 300 is inserted into the hollow interior of the holder lock 700. A lock side groove (not shown) is formed on the inner surface of the holder lock 700. The holder side rib 358 (see Figures 1 and 2) of the syringe holder 350 is slidably engaged with the lock side groove. When the syringe unit 300 moves within the holder lock 700, the holder side rib 358 is guided by the lock side groove.

[0054] The needle assembly 400 includes a double-ended needle 402 and a needle hub 404 that holds the double-ended needle 402. The needle hub 404 is held in a holding hole 119 of a needle holding portion 118 provided at the tip inside the housing 100.

[0055] The double-ended needle 402 has a first needle portion 406 and a second needle portion 408. The first needle portion 406 protrudes from the needle hub 404 toward the tip. In Figure 2, the tip of the first needle portion 406 and the base of the second needle portion 408 are shown in enlarged view within the circle. As shown in this enlarged view, the first needle portion 406 is a hollow body having a first lumen 410. An administration port 412 opens at the tip of the first needle portion 406. The administration port 412 communicates with the first lumen 410. The tip of the first needle portion 406 is inserted into the patient's body B (see Figure 4). The second needle portion 408 protrudes from the needle hub 404 toward the base. The second needle portion 408 is a hollow body having a second lumen 414. An inlet 416 opens at the base of the second needle portion 408. The receiving port 416 communicates with the second lumen 414. The proximal end of the second needle portion 408 punctures the sealing member 340.

[0056] The first lumen 410 and the second lumen 414 are in communication with each other. Therefore, the receiving port 416 is in communication with the administration port 412 via the second lumen 414 and the first lumen 410. The receiving port 416, the second lumen 414, the first lumen 410, and the administration port 412 form the flow path for the drug solution M.

[0057] As shown in Figures 2 and 3, in the initial state, the first needle portion 406 is covered by the tip cover portion 202 of the needle cover 200. The second needle portion 408 is covered by the cylindrical cover portion 204. The base end of the second needle portion 408 is located beyond, for example, the insertion hole 332 formed at the tip of the cap 330.

[0058] The tip of the needle holder 118 is inserted into the opening on the base end of the cover spring 250. In other words, the base end of the cover spring 250 is held by the tip of the needle holder 118. On the other hand, the tip of the cover spring 250 is in contact with the inner surface of the tip cover portion 202 of the needle cover 200. Therefore, the elastic force of the cover spring 250 biases the needle cover 200 so that it moves relative to the housing 100 and the needle assembly 400 toward the tip.

[0059] The plunger 500 shown in Figures 1 to 3 is a component for moving the gasket 342 toward the tip of the barrel 304. The plunger 500 is a cylindrical body that extends axially and has a hollow interior. The retaining shaft portion 148 of the end cap 140 is inserted into the hollow interior of the plunger 500 through an opening at the base end. An injection spring 160 is inserted between the side circumferential wall of the retaining shaft portion 148 and the inner circumferential wall of the plunger 500. The axial length of the injection spring 160 is greater than the axial length of the retaining shaft portion 148. The tip of the injection spring 160 abuts against the inner surface of the tip of the plunger 500. The base end of the injection spring 160 abuts against the inner surface of the base end of the lid portion 142 of the end cap 140. Therefore, the elastic force of the injection spring 160 biases the plunger 500 so that it moves toward the tip.

[0060] The tip of the plunger 500 is inserted into the barrel body 312 of the syringe 302. The tip of the plunger 500 abuts against the base end face of the gasket 342. In the initial state, the tip of the plunger 500 may be spaced a predetermined distance from the base end face of the gasket 342.

[0061] As shown in Figure 3, a pair of grooves 502 are symmetrically formed on the outer surface of the side wall of the plunger 500. The pair of grooves 502 extend along the axial direction of the plunger 500. A pair of base-side stoppers 506 are provided at the base ends of each of the grooves 502. A pair of locking holes 508 are formed on the side wall of the plunger 500, closer to the base end than the base-side stoppers 506.

[0062] A stopper ring 520, which is a ring body, is passed through the base end of the plunger 500. The base-side stopper 506 and the stopper ring 520 constitute a movement-stopping section 550. In the initial state, the tip end face of the stopper ring 520 is in contact with the base end face of the flange portion 314 of the syringe 302.

[0063] A pair of engaging projections 526 are symmetrically provided at the base end of the stopper ring 520. The pair of engaging projections 526 each protrude radially inward from the inner circumferential wall of the base end of the stopper ring 520. The engaging projections 526 engage with the groove 502 of the plunger 500 so as to be movable relative to it.

[0064] As shown in Figures 2 and 3, the drug dispensing device 10 is equipped with a locking mechanism 600. The locking mechanism 600 has a cylindrical locking body 610, a cylindrical locking sleeve 640, and a locking sleeve spring 670. In its initial state, the locking mechanism 600 prevents the plunger 500 from moving toward the tip.

[0065] The lock body 610 surrounds the base end of the plunger 500. The lock body 610 is positioned inside the end cap 140. A pair of body side holes 612 are symmetrically formed on the side wall of the lock body 610. As shown in Figure 2, a pair of cap side claws 152, provided on the small diameter cylindrical portion 146 of the end cap 140, engage with the pair of body side holes 612. This engagement connects the lock body 610 to the end cap 140.

[0066] The lock body 610 has a pair of radially elastically deformable engaging arm portions 614. The pair of engaging arm portions 614 are elastically deformable with their base ends as pivot points. Each of the inner surfaces of the tips of the pair of engaging arm portions 614 is provided with a locking claw 616 (see Figure 3). The locking claw 616 engages with the locking hole 508 of the plunger 500. At this time, since the locking sleeve 640 is arranged on the outer circumference of the engaging arm portion 614, the engaging arm portion 614 is prevented from bending radially outward. This maintains the engagement between the locking claw 616 and the locking hole 508. As a result, in the initial state, the plunger 500 is prevented from moving toward the tip. In other words, the plunger 500 is locked.

[0067] As shown in Figure 2, the lock body 610 further has a pair of body-side protrusions 622 that project radially outward from the circumferential wall. The body-side protrusions 622 are formed at the tip of the outer surface of the side wall of the lock body 610 and project radially outward.

[0068] The lock sleeve 640 has a cylindrical portion 642 and a large-diameter ring portion 644 provided at the tip of the cylindrical portion 642. The large-diameter ring portion 644 extends radially outward from the base end of the cylindrical portion 642. In the puncture state, the base end of the extension portion 206 of the needle cover 200 comes into contact with the large-diameter ring portion 644. This causes the lock sleeve 640 to be pushed toward the base end.

[0069] As shown in Figure 1, a pair of U-shaped holes 646 are formed in the peripheral wall of the lock sleeve 640. The U-shaped holes 646 extend from the large-diameter ring portion 644 toward the proximal end. A pair of hook portions 648 are positioned inside each U-shaped hole 646. The tips of the hook portions 648 are connected to the large-diameter ring portion 644. That is, the hook portions 648 are supported only by the large-diameter ring portion 644. Body-side protrusions 622 are inserted into each U-shaped hole 646 (see Figure 2). When the puncture procedure is completed and the first needle portion 406 is detached from the patient's body B, the body-side protrusions 622 are sandwiched between the inner surface of the U-shaped hole 646 and the proximal end of the hook portion 648 (see Figure 8). Based on this, movement of the lock sleeve 640 along the axial direction is prevented.

[0070] As shown in Figure 2, the lock sleeve spring 670 is sandwiched between the lid portion 142 of the end cap 140 and the large-diameter ring portion 644 of the lock sleeve 640. Therefore, the elastic force of the lock sleeve spring 670 biases the lock sleeve 640 toward the tip.

[0071] The drug administration device 10, configured as described above, is housed in a packaging container (not shown) before the puncture procedure is performed. Here, the packaging container has a locking projection. The locking projection is inserted into the housing 100 through the hole 112. The locking projection abuts against the proximal end face of the large-diameter ring portion 644 of the lock sleeve 640. This prevents the lock body 610 from moving toward the proximal end.

[0072] An air pocket AP (see Figures 2 and 3) may form in the drug solution M within the drug chamber 322. When the drug dispensing device 10 is positioned with its axial direction aligned horizontally, as shown in Figures 2 and 3, the air pocket AP is located, for example, at the top of the tip of the barrel body 312.

[0073] Next, we will explain the procedure for removing the drug administration device 10 from the packaging container and performing the puncture.

[0074] The user inserts their finger into the packaging container and removes the drug dispensing device 10 from the packaging container. At this time, the locking projection provided on the packaging container detaches from the hole 112 in the housing 100. This releases the plunger 500 and other components from being constrained by the packaging container.

[0075] The drug dispensing device 10, after being removed from its packaging, is in the initial state shown in Figures 2 and 3. In the initial state of the drug dispensing device 10, the locking claw 616 of the engaging arm portion 614 of the lock body 610 is inserted into the locking hole 508 of the plunger 500 from the radially outward direction. Here, the lock sleeve 640 is biased toward the tip by the lock sleeve spring 670. This prevents the engaging arm portion 614 from elastically deforming toward the radially outward direction. The locking mechanism 600 thereby locks the plunger 500. That is, it prevents the plunger 500 from moving toward the tip.

[0076] The user grasps the housing 100 of the drug administration device 10. Next, as shown in Figure 4, the user presses the tip cover portion 202 of the needle cover 200, which protrudes from the tip of the housing 100, against the puncture site on the patient's body B at approximately a right angle. Note that in Figure 4, as in Figures 2 and 3, the drug administration device 10 is shown in a position extending horizontally, with the tip cover portion 202 pressed against the puncture site.

[0077] From this position, the user pushes the housing 100 toward body B (towards the tip). This causes the needle cover 200 to be pushed by body B, resulting in the needle cover 200 moving relative to the housing 100 toward the base end. At this time, the cover spring 250 is compressed.

[0078] As the needle cover 200 moves relative to the proximal end, as shown in Figure 4, the first needle portion 406 of the double-ended needle 402 protrudes from the needle hole 208 of the needle cover 200. As a result, the first needle portion 406 is punctured into body B and inserted to a predetermined depth. That is, the drug administration device 10 enters a puncture state. At this point, the administration port 412 formed at the tip of the first needle portion 406 is located inside the patient's body B.

[0079] As the needle cover 200 moves relative to the base end as described above, the base end of the extension 206 of the needle cover 200 comes into contact with the large-diameter ring 644 of the lock sleeve 640. As a result, the lock sleeve 640 is pushed by the extension 206 and moves towards the base end. This compresses the lock sleeve spring 670 and moves the lock sleeve 640 towards the base end. The lock sleeve 640 reaches beyond the engaging arm 614 towards the base end. Therefore, the lock claw 616 is released from the constraint of the lock sleeve 640. For this reason, the engaging arm 614 can elastically deform radially outward.

[0080] The injection spring 160 biases the plunger 500 toward the tip. As a result, the engaging arm portion 614 tilts along the lock hole 508. This tilting causes the locking claw 616 to move radially outward. Consequently, the locking claw 616 disengages from the lock hole 508 (see Figure 6).

[0081] This releases the lock on the plunger 500 by the locking claw 616. In other words, the drug delivery device 10 becomes unlocked. Consequently, the plunger 500 begins to move toward the tip due to the elastic force of the injection spring 160. Thus, the needle cover 200 acts as an activation switch that changes the drug delivery device 10 from its initial state to an unlocked state, making the plunger 500 movable.

[0082] As the plunger 500 begins to move toward the tip, the tip of the plunger 500 comes into contact with the base end of the gasket 342. Subsequently, the gasket 342 is pushed toward the tip by the moving plunger 500. Thus, the plunger 500 and the gasket 342 are in a state where they can move together as a single unit. Here, the tip opening 316 of the nozzle portion 306 in the barrel 304 is liquid-tightly closed by the sealing member 340. Thus, leakage of the chemical solution M in the chamber 322 of the barrel 304 from the tip opening 316 is prevented.

[0083] The gasket 342 receives a reaction force from the chemical solution M in the chamber 322. Therefore, the gasket 342 cannot move towards the tip relative to the barrel 304 within the chamber 322. In contrast, the plunger 500 is subjected to the elastic force of the injection spring 160. Consequently, the plunger 500 attempts to move towards the tip within the housing 100. As a result, the barrel 304 is pushed by the plunger 500 via the gasket 342.

[0084] At this time, the inner claw 710 of the holder lock 700 disengages from the first claw hole 360 ​​formed in the syringe holder 350. This releases the syringe unit 300 from the constraint of the holder lock 700. Consequently, the syringe unit 300 moves relative to the housing 100 toward the tip, as shown in Figure 4. During this movement, the holder-side rib 358 is guided into the lock-side groove. Simultaneously, the outer guide rib 370 provided in the flange housing portion 356 of the syringe holder 350 is guided into the inner guide groove 116 formed on the inner surface of the housing 100. Based on the engagement between the holder-side rib 358 and the lock-side groove, and the engagement between the outer guide rib 370 and the inner guide groove 116, tilting of the syringe unit 300 relative to the housing 100 is prevented. In other words, it is easy to move the syringe unit 300 straight toward the tip.

[0085] As described above, when the syringe unit 300 moves relative to the tip within the holder lock 700 or housing 100, the base end of the second needle portion 408 of the double-ended needle 402 is inserted into the insertion hole 332 of the cap 330. The base end of the second needle portion 408 penetrates the sealing member 340 and is inserted into the insertion hole 318 via the tip opening 316 of the nozzle portion 306.

[0086] As the syringe unit 300 moves further toward the tip, the outer guide rib 370 reaches the tip end of the inner guide groove 116. In this state, the tip end face of the outer guide rib 370 abuts against the tip inner surface of the inner guide groove 116. This abutment prevents the syringe unit 300 from moving toward the tip. In other words, the syringe unit 300 stops within the housing 100. At this time, the inner claw 710 of the holder lock 700 engages with the second claw hole 362 formed in the syringe holder 350. Consequently, the syringe unit 300 is re-restrained by the holder lock 700.

[0087] During this movement, the base end of the second needle portion 408 passes over the base end of the nozzle portion 306 of the barrel 304. Specifically, the base end of the second needle portion 408 reaches the inside of the shoulder portion 310 of the barrel 304 through the base end opening 320 of the nozzle portion 306.

[0088] An inlet 416 opens at the base end of the second needle portion 408. The inside of the shoulder portion 310 is part of the drug chamber 322. Therefore, in this embodiment, the inlet 416 is located further to the base (base end opening 320) of the nozzle portion 306 of the barrel 304 and reaches the drug chamber 322. The drug chamber 322 of the syringe 302 is in communication with the administration port 412 via the inlet 416, the second lumen 414 of the second needle portion 408, and the first lumen 410 of the first needle portion 406. Therefore, the drug solution M in the drug chamber 322 can flow out of the administration port 412 via the inlet 416, the second lumen 414, and the first lumen 410. In other words, the second needle portion 408 and the syringe 302 are connected, and as a result, the sealed state of the drug chamber 322 is released.

[0089] Even after the syringe unit 300 stops moving toward the tip, the elastic force of the injection spring 160 is still applied to the plunger 500. As described above, the syringe unit 300 is stopped within the housing 100, and the sealing state of the drug chamber 322 is released. Therefore, the plunger 500 and gasket 342 move together toward the tip within the barrel 304 without being subjected to the reaction force of the drug solution M. Based on this movement, the drug solution M in the drug chamber 322 flows into the second lumen 414 through the receiving port 416. The drug solution M then passes through the first lumen 410 and flows into the patient's body B through the administration port 412, as shown in Figure 5. In this way, the drug solution M is administered to the patient.

[0090] As the plunger 500 and gasket 342 move within the barrel 304 as described above, the air pocket AP formed in the drug solution M moves, for example, to the insertion hole 318. Here, the receiving port 416 for receiving the drug solution M is located in the drug chamber 322 beyond the insertion hole 318 and the proximal opening 320. Therefore, while the drug solution M is being administered to the patient, the flow of the air pocket AP in the insertion hole 318 into the receiving port 416 is suppressed.

[0091] As the plunger 500 and gasket 342 move within the barrel 304, the engaging projection 526 of the stopper ring 520 moves relative to the groove 502 of the plunger 500. At this time, the tip end face of the engaging projection 526 gradually approaches the base end stopper 506. Immediately after a predetermined amount of drug solution M is administered to the patient, the tip end face of the engaging projection 526 comes into contact with the base end stopper 506, as shown in Figure 6. This contact prevents the plunger 500 from moving in the tip direction. In other words, the movement stopper 550 stops the plunger 500 and gasket 342 within the barrel 304. As a result, the gasket 342 reaches the administration completion position. In other words, the drug solution administration device 10 reaches the administration completion state, where the administration of drug solution M to the patient is complete.

[0092] When the administration of drug solution M to the patient is complete, a predetermined amount of drug solution M remains in the drug chamber 322. In other words, the patient receives a predetermined amount of drug solution M from the drug chamber 322, but not the entire amount. As described above, while drug solution M is being administered to the patient, the air pocket AP in the insertion hole 318 is prevented from flowing into the receiving port 416. Therefore, it is prevented that drug solution M is administered to the patient through the administration port 412 while entrained with air from the air pocket AP.

[0093] In other words, the entrainment of air into the drug solution M discharged from the administration port 412 of the first needle portion 406 is suppressed. Therefore, the drug solution M can be administered to the patient in a predetermined prescribed dose. Thus, according to this embodiment, since the receiving port 416 of the second needle portion 408 is positioned more towards the proximal end than the proximal end of the nozzle portion 306, it is easy to administer the drug solution M to the patient in a prescribed dose.

[0094] As shown in Figure 7, the drug dispensing device 10 may be positioned with its tip pointing vertically upward and its base pointing vertically downward. In this case, the air reservoir AP is located, for example, near the tip opening 316 of the nozzle portion 306. The drug dispensing device 10 may also be positioned to extend along a direction between the vertical and horizontal directions.

[0095] As described above, the receiving port 416 for receiving the drug solution M is located in the drug chamber 322, beyond the insertion hole 318 and the proximal opening 320. While the drug solution M is being administered to the patient, it is difficult for the air pocket AP near the tip opening 316 to descend through the insertion hole 318 and reach the drug chamber 322. Therefore, even in this case, the inflow of the air pocket AP into the receiving port 416 is suppressed. As a result, it is avoided that the drug solution M, which contains the air pocket AP, is administered to the patient through the administration port 412.

[0096] Furthermore, if the thickness of the stopper ring 520 is different, the stopping position of the plunger 500 will differ. Consequently, the amount of drug solution M administered to the patient will also change. As can be understood from this, by configuring the drug solution administration device 10 using stopper rings 520 of different thicknesses, it is possible to change the prescribed amount of drug solution M administered to the patient.

[0097] After the administration of drug solution M is complete, the user separates the tip cover portion 202 of the needle cover 200 from the patient's body B, as shown in Figure 8. As this separation occurs, the cover spring 250 extends. The elastic force of the cover spring 250 biases the needle cover 200 toward the tip. As a result, the tip cover portion 202 protrudes from the front of the housing 100. The tip of the tip cover portion 202 is located further forward than the tip of the first needle portion 406 of the double-ended needle 402. This ensures that the needle cover 200 completely covers the first needle portion 406 of the double-ended needle 402.

[0098] As the needle cover 200 moves toward the tip, the lock sleeve 640 is released from the pressure exerted by the needle cover 200 toward the base end. Consequently, the lock sleeve 640 is biased by the elastic force of the lock sleeve spring 670 and moves toward the tip. At this time, the lock sleeve 640 pushes the lock claw 616 inward. As a result, the engaging arm portion 614 elastically deforms so as to move radially inward. This causes the lock sleeve 640 to move toward the tip, overcoming the lock claw 616.

[0099] As the lock sleeve 640 moves toward the tip of the lock body 610, the body-side projection 622 of the lock body 610 is inserted into the U-shaped hole 646 of the lock sleeve 640. The body-side projection 622 is sandwiched between the base end of the hook portion 648 and the inner surface of the U-shaped hole 646. This positions and fixes the lock sleeve 640 to the lock body 610. In other words, axial movement of the lock sleeve 640 is prevented.

[0100] The extension 206 of the needle cover 200 abuts against the large-diameter ring portion 644 of the lock sleeve 640. This prevents the needle cover 200 from moving in the proximal direction. Therefore, even if a force is applied to push the needle cover 200 in the proximal direction after puncture, the first needle portion 406 of the double-ended needle 402 is prevented from being exposed to the outside of the needle cover 200. Thus, contact between the first needle portion 406 and the user after puncture is avoided.

[0101] Furthermore, the present invention is not limited to the disclosure described above, and can take various configurations without departing from the spirit of the invention. [Explanation of Symbols]

[0102] 10…Medication dispensing device 100…Housing 102...First opening 104...Second opening 116...Internal guide groove 118...Needle holding part 124... Stopper rib 140... End cap 148...Holding shaft section 150...Connecting projection 152...Cap-side claw 160...Injection spring 200... Needle cover 202... Tip cover 208... Needle hole 250... Cover spring 300... Syringe unit 302... Syringe 304...Barrel 306...Nozzle 308... Barrel body 310... Shoulder part 312... Barrel section 314... Flange section 316…Tip opening 318…Insertion hole 320…Proximal opening 322…Cancer chamber 332…Through hole 340…Sealing member 342...Gasket 350...Syringe holder 358…Holder-side rib 360…First claw hole 362...Second claw hole 370...Outer guide rib 400... Needle assembly 402... Double-ended needle 406...First needle section 408...Second needle section 410...First lumen 412...Injection port 414...Second lumen 416...Intake port 500...Plunger 502...Deep groove 506... Base end stopper 508... Locking hole 520... Stopper ring 526... Engaging projection 550...Movement stop part 600...Locking mechanism 610... Lock body 612... Body side hole 616... Locking claw 622... Protrusion on the body side 640... Lock sleeve 644... Large diameter ring 646...U-shaped hole 648...Hook part 670... Lock sleeve spring 700... Holder lock 704...External engaging claw 708...Flexible arm 710...Inner claw AP...Air pocket B...Body M...Medicinal liquid

Claims

1. A hollow cylindrical housing, A syringe comprising a barrel, a chamber formed within the barrel and filled with a drug solution, and a gasket that is liquid-tight and slidable inside the barrel, wherein the barrel comprises a barrel body housing the gasket, a cylindrical nozzle portion protruding from the barrel body toward the tip, and a sealing member that liquid-tightly seals the tip opening of the nozzle portion, and the syringe housed within the housing so as to be relatively movable toward the tip relative to the housing, A plunger moves relative to the housing in the direction of the tip and pushes the gasket toward the tip, A double-ended needle having a first needle portion that protrudes toward the tip to puncture the target and a second needle portion that protrudes toward the proximal end toward the syringe, wherein the second needle portion is located inside the housing and the first lumen of the first needle portion and the second lumen of the second needle portion are in communication, A movement stopper is provided to stop the movement of the plunger toward the tip so that the gasket stops at a dispensing completion position where the gasket is separated from the tip of the barrel body toward the base end by a predetermined distance, A drug dispensing device equipped with, The second needle portion has an opening that communicates with the second lumen and receives the drug solution in the drug chamber, A drug dispensing device wherein, as the syringe moves relative to the housing in the direction of the tip, the second needle portion is inserted into the nozzle portion and the connection of the second needle portion to the barrel is completed, the receiving port of the second needle portion is located between the base end of the nozzle portion and the gasket.

2. A drug dispensing device according to claim 1, wherein the barrel body has a body portion and a shoulder portion interposed between the body portion and the nozzle portion and decreasing in diameter as it approaches the nozzle portion, and the receiving port of the second needle portion is located inside the shoulder portion or inside the body portion.

3. In the drug administration device according to claim 1, the movement stopper includes a ring body that is passed through the plunger and is movable relative to the plunger, The plunger has a projection at its tip that protrudes from the side wall of the plunger in a direction perpendicular to the axial direction of the plunger, The plunger is a drug dispensing device in which, when it moves toward the tip, the protrusion comes into contact with the ring body, thereby stopping its movement toward the tip.

4. A drug administration device according to claim 1, comprising a syringe holder arranged on the outer circumference of the syringe to hold the syringe and movably disposed inside the housing, A drug administration device wherein the syringe holder moves integrally with the syringe toward the tip while being guided by the housing.

5. A drug administration device according to claim 4, wherein the housing has a first guide portion and the syringe holder has a second guide portion, and one of the first guide portion or the second guide portion is a guide hole, and the other of the first guide portion or the second guide portion is a guide projection movably inserted into the guide hole, A drug administration device wherein the movement of the syringe holder and the syringe stops when the guide projection reaches the tip end of the guide hole.

6. The drug administration device according to claim 4, further comprising a holder lock for positioning the syringe holder, The holder lock has a first engaging portion, The syringe holder has a second engaging portion, In the initial state, the syringe holder is positioned within the housing by the engagement of the first engaging portion and the second engaging portion with each other. A drug administration device wherein the syringe holder and the syringe can move integrally within the housing when the engagement between the first engaging portion and the second engaging portion is released.

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