Preventing reuse of pre-filled syringes

Abstract

The application relates to the technical field of medical devices, in particular to a pre-filled syringe for preventing reuse. The pre-filled syringe comprises an outer cylinder, a medicament outlet located at the front end of the outer cylinder and communicating with the inner cavity, the inner cavity having a circumferential wall and a front side wall, and the medicament outlet penetrating through the front side wall; a medicament accommodated in the inner cavity; a plunger slidably accommodated in the inner cavity and composed of an elastomer; a push rod for pushing the plunger to move forward in the inner cavity so that the medicament is guided out of the medicament outlet; an annular groove extending in the circumferential direction is formed on the circumferential wall, and a protrusion protruding outward is formed on the circumferential surface of the plunger; when the plunger is pushed to be in contact with the front side wall, the protrusion is embedded in the annular groove under the action of elastic restoring force.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a pre-filled syringe designed to prevent reuse. Background Technology

[0002] Currently used pre-filled syringes in clinical practice contain sealed medication, eliminating the need for on-site medication preparation by medical staff and making drug administration convenient. However, existing pre-filled syringes lack a one-way limiting and locking structure. After injection, the plunger can be pulled back to its original position, and the inner cavity can be refilled with medication or other liquids, making them easy to reuse. This can lead to cross-infection among patients, and children picking them up and playing with them pose a safety hazard of accidental ingestion. Summary of the Invention

[0003] In view of this, this application provides a pre-filled syringe that prevents reuse.

[0004] The pre-filled syringe for preventing reuse proposed in this application includes: An outer cylinder has an inner cavity and a drug outlet located at the front end of the outer cylinder and communicating with the inner cavity. The inner cavity has a circumferential wall and a front side wall, and the drug outlet penetrates the front side wall. The medicine is contained within the cavity. The plunger is slidably housed within the cavity and is made of an elastomer; A push rod is used to push the plunger forward within the cavity to allow the medicine to be discharged from the medicine outlet. The circumferential wall has an annular groove extending in the full circumferential direction, and the circumferential surface of the plunger has a protrusion protruding outward. In the initial state, the protrusion is pressed inward by the circumferential wall, and the circumferential surface of the plunger is in sealing contact with the wall surface of the circumferential wall throughout the entire circumference; when the plunger is pushed by the push rod to contact the front side wall, the protrusion is embedded in the annular groove under the action of elastic restoring force.

[0005] In some possible implementations, the push rod engages with the plunger but is not connected, wherein when the push rod is actuated to move forward, the plunger is pushed by the push rod and moves forward with the push rod, and when the push rod is actuated to fold backward, the plunger separates from the push rod.

[0006] In some possible implementations, the connection force between the push rod and the plunger is smaller than the engagement force between the protrusion and the annular groove, thereby causing the push rod to separate from the plunger when the push rod is actuated and folded back, provided that the protrusion is engaged in the annular groove under the action of elastic restoring force.

[0007] In some possible implementations, the push rod has a ball-cutting head extending forward, which is embedded in a groove formed in the rear end face of the plunger.

[0008] In some possible implementations, the protrusion has a front surface and a rear surface disposed opposite to each other, wherein the front surface is formed as an inclined surface that slopes backward in a direction away from the centerline of the plunger.

[0009] In some possible implementations, the rear surface is formed as an inclined surface that slopes backward in a direction away from the centerline.

[0010] In some possible implementations, the rear wall of the annular groove is formed as an inclined surface that slopes forward in a direction close to the centerline.

[0011] In some possible implementations, the rear surface is formed as a vertical surface perpendicular to the centerline. In some possible implementations, forward-protruding spikes are formed on the rear wall surface of the annular groove.

[0012] In some possible implementations, the push rod includes a rod portion and a plunger head integrally formed at the front end of the rod portion; The outer cylinder includes a body defining the inner cavity and a blocking member installed at the rear end of the body, the blocking member preventing the push rod from completely disengaging from the inner cavity by blocking the plunger push head.

[0013] According to the pre-filled syringe provided in this application, an annular groove extending in the full circumferential direction is formed on the circumferential wall of the inner cavity, and a protrusion protruding outward on the circumferential surface of the plunger is formed. When the plunger is pushed to the injection completion position in contact with the front side wall, the protrusion on the plunger is embedded in the annular groove under the action of elastic restoring force, thereby preventing the plunger from moving back to its original position when the plunger is withdrawn. Structurally, this eliminates the possibility of the syringe being reused, greatly reduces the risk of cross-infection, and better meets the regulatory requirements for disposable medical devices. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application, and are not intended to limit this application.

[0015] Figure 1 This is a schematic diagram of the pre-filled syringe provided in this application embodiment before use.

[0016] Figure 2 This is a schematic diagram of the pre-filled syringe provided in this application after injection.

[0017] Figure 3 yes Figure 2 Enlarged view of part X1.

[0018] Figure 4 This is a schematic diagram of the pre-filled syringe provided in this application after injection.

[0019] Figure 5 yes Figure 4 Enlarged view of part X2.

[0020] Figure 6 This is a schematic diagram of the pre-filled syringe provided in this application after injection.

[0021] Figure 7 yes Figure 6 Enlarged view of part X3.

[0022] Figure 8 This is a schematic diagram of the pre-filled syringe provided in this application embodiment before use.

[0023] Figure 9 This is a schematic diagram of the pre-filled syringe provided in this application after injection.

[0024] Figure 10 yes Figure 9 Enlarged view of part X4.

[0025] Figure 11 This is a schematic diagram of the pre-filled syringe provided in this application after injection.

[0026] Figure 12 yes Figure 11 Enlarged image of part X5.

[0027] Figure 13 This is a three-dimensional schematic diagram of the pre-filled syringe provided in the embodiments of this application.

[0028] Figure 14 This is an exploded view of a portion of the pre-filled syringe provided in an embodiment of this application.

[0029] Figure 15 This is a schematic diagram of the cooperation between the blocking component and the flange of the pre-filled syringe provided in the embodiments of this application.

[0030] Explanation of reference numerals in the attached figures: 100-syringe; 10-Outer cylinder, 20-Plunger, 30-Push rod, 40-Cap, 50-Blocking component, 60-Reagent; 11-Cylinder body, 12-Front nozzle, 12a-Pharmaceutical outlet, 13-Flange, 13a-Card hole, 14-Inner cavity, 14a-Circumferential wall, 14b-Front side wall, 15-Protrusion, 16-Annular groove, 16a-Rear wall surface, 16b-Spirit; 21-Protrusion, 21a-Front surface, 21b-Rear surface; 31-Lever section, 32-Plunger push head, 32a-Ball cutter head, 33-Actuator handle; 51-Protrusion, 52-Notch, 5a-Through hole. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the described embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0032] In the description of this application, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects, and, for example, the term "first element" itself does not imply the existence of a "second element," nor does the term "second element" itself imply the existence of a "first element." Furthermore, words such as "a" or "one" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates not less than two.

[0033] Figures 1 to 15 Some embodiments of the pre-filled syringes 100 of this application are shown, in which each syringe 100 includes an outer barrel 10, a plunger 20, a push rod 30, and a cap 40.

[0034] The outer cylinder 10 includes a hollow cylinder 11, a front nozzle 12 integrally formed at the front end of the cylinder 11 and smaller than the diameter of the cylinder 11, and a flange portion 13 integrally formed at the rear end of the cylinder 11. The cylinder 11, the front nozzle 12, and the flange portion 13 can be formed of resin. The cylinder 11 has a cylindrical inner cavity 14, which contains an injectable drug 60. The front nozzle 12 has a drug outlet 12a communicating with the inner cavity 14. Since the drug outlet 12a communicates with the inner cavity 14, a portion of the drug 60 fills the drug outlet 12a. The inner cavity 14 has a circumferential wall 14a and a front side wall 14b, and the drug outlet 12a penetrates the front side wall 14b.

[0035] The cap 40 is detachably mounted on the front nozzle 12 and closes the medicine outlet 12a inside the front nozzle 12. Thus, the cap 40 and the plunger 20 seal the medicine 60 in the inner cavity 14 without leakage.

[0036] The plunger 20 is made of an elastic body and is slidably housed in the inner cavity 14 of the cylinder 11. The plunger 20 in the inner cavity 14 is subjected to the inward circumferential pressure of the circumferential wall 14a of the cylinder 11, thereby sealing the plunger 20 against the circumferential wall 14a and sealing the agent 60 in the inner cavity 14 between the plunger 20 and the cap 40.

[0037] The push rod 30 includes a straight-extending rod portion 31, a plunger push head 32 integrally formed at the front end of the rod portion 31, and an actuation handle 33 integrally formed at the rear end of the rod portion 31. The rod portion 31, the plunger push head 32, and the actuation handle 33 may also be formed of resin.

[0038] When injecting the drug 60 using the syringe 100, the cap 40 is removed and the injection needle (not shown) is installed on the front nozzle 12. By pushing the actuator handle 33 of the push rod 30 forward, the push rod 30 moves forward as a whole. The plunger push head 32 at the front end of the push rod 30 pushes the plunger 20 to move forward, thereby allowing the drug 60 in the inner cavity 14 to be discharged through the drug outlet 12a and the injection needle, thus realizing the push injection of the drug 60.

[0039] The rod portion 31 is formed with a rectangular cross section, and therefore, the cross section of the rod portion 31 has a width and a length greater than the width; the plunger push head 32 and the actuation handle 33 are formed with circular cross sections, and the cross-sectional dimensions of the plunger push head 32 and the actuation handle 33 are larger than the cross-sectional dimensions of the rod portion 31.

[0040] The plunger push head 32 has a ball-cutting head 32a extending forward, which is slightly larger than half a sphere. This ball-cutting head 32a is embedded in a groove formed on the rear end face of the plunger 20, thereby achieving a weak connection (lower connection force) between the push rod 30 and the plunger 20. The engagement force between the ball-cutting head 32a and the groove of the plunger 20 is less than the engagement force between the protrusion 21 and the annular groove 16.

[0041] exist Figures 1 to 7 In the various embodiments shown, an annular groove 16 extending in the full circumferential direction is formed on the circumferential wall 14a of the inner cavity 14, and a protrusion 21 protruding outwardly is formed on the circumferential surface of the plunger 20. In the initial state (the state before use), as... Figure 1As shown, the protrusion 21 is pressed inward by the circumferential wall 14a, thereby sealing the circumferential surface of the plunger 20 with the wall surface of the circumferential wall 14a throughout the entire circumference; when the plunger 20 is pushed by the push rod 30 to contact the front wall 14b of the inner cavity 14 (in the injection completed state), as... Figure 2 , Figure 4 , Figure 6 As shown, the protrusion 21 is embedded in the annular groove 16 under the action of elastic restoring force. With this design, after the drug 60 in the syringe 100 has been injected, if the plunger 30 is pulled backward to retract the plunger 20 and refill the inner cavity 14 with drug 60 or other liquid (e.g., by aspiration from the drug outlet 12a), the plunger 20 will not move backward with the plunger 30 because the protrusion 21 on the plunger 20 is embedded in the annular groove 16 of the outer cylinder 10, and the connection between the plunger 30 and the plunger 20 is weak. The connection force between the plunger 30 and the plunger 20 is smaller than the engagement force between the protrusion 21 and the annular groove 16. Therefore, the plunger 20 remains in the annular groove 16. Figure 2 , Figure 4 , Figure 6 As shown in the injection completion position, the retracted plunger 30 separates from the plunger 20, thus preventing the syringe 100 from being reused.

[0042] In some possible implementations, the push rod 30 and the plunger 20 only contact but are not connected. When the push rod 30 is actuated and moves forward, the plunger 20 is pushed by the push rod 30 and moves forward with it. When the push rod 30 is actuated and folds back, the plunger 20 separates from the push rod 30. For example, the front end face of the plunger push head 32 at the front end of the push rod 30 is a flat surface without a ball-cutting head 32a. Before use, this flat surface contacts but is not connected to the rear end face of the plunger 20. Therefore, when the push rod 30 is forced to move backward, the plunger 20 will not move backward with it. In this implementation, the initial position of the push rod 30 can be positioned by a tearable adhesive seal.

[0043] In some embodiments, the protrusions 21 on the plunger 20 are formed as flanges extending over the entire circumference. In other embodiments, the protrusions 21 are formed as dots, and a plurality of dots are arranged evenly around the plunger 20.

[0044] The protrusion 21 has a front surface 21a and a rear surface 21b that are disposed opposite to each other in the front-rear direction.

[0045] exist Figures 1 to 3In the illustrated embodiment, the front surface 21a of the protrusion 21 is formed as an inclined surface that slopes further backward in the radial direction the further away from the centerline of the plunger 20, and the rear surface 21b is formed as a vertical surface perpendicular to the centerline. This design helps to reduce friction between the protrusion 21 and the cylinder 11 during injection, making the injection operation smoother; it also helps to increase the engagement force between the protrusion 21 and the annular groove 16, preventing the plunger 20 from moving backward along with the push rod 30.

[0046] exist Figure 4 and Figure 5 In the illustrated embodiment, both the front surface 21a and the rear surface 21b of the protrusion 21 are formed as inclined surfaces that slope backward in a direction away from the centerline of the plunger 20. This design helps to reduce friction between the protrusion 21 and the cylinder 11 during injection, making the injection operation smoother. It also helps to increase the engagement force between the protrusion 21 and the annular groove 16, preventing the plunger 20 from moving backward with the push rod 30. Furthermore, the inclined rear surface 21b forms an acute-angle space with the plunger 20 body, which... Figure 1 In the corresponding state, the acute-angled space provides space for the protrusion 21 to collapse and deform inward, so that the protrusion 21 of the plunger 20 collapses inward to seal against the wall surface of the circumferential wall 14a.

[0047] And in Figure 4 and Figure 5 In the illustrated embodiment, the rear wall surface 16a of the annular groove 16 is formed as an inclined surface that slopes forward in the direction close to the center line of the plunger 20, so that when the plunger 20 is pushed to... Figure 4 and Figure 5 When the injection is completed as shown, the rear wall 16a of the annular groove 16 is located in the aforementioned acute-angle space. Even if a relatively large backward thrust is applied to the plunger 20, the protrusion 21 on the plunger 20 is unlikely to go over the rear wall 16a of the annular groove 16.

[0048] exist Figure 6 and Figure 7 In the illustrated embodiment, forward-protruding spikes 16b are formed on the rear wall surface 16a of the annular groove 16. With this design, when the plunger 20 moves to the injection completion position, the spikes 16b pierce forward into the protrusion 21 of the plunger 20. Therefore, even if a relatively large backward thrust is applied to the plunger 20, the protrusion 21 on the plunger 20 is unlikely to cross the rear wall surface 16a of the annular groove 16.

[0049] It should be understood that injection molds with retractable snap-fit ​​cores can be used to manufacture... Figure 3 , Figure 4 and Figure 7The outer cylinder 10 shown in any of the embodiments may have a shrinkable, flap-shaped core, for example, a half-shaped core comprising multiple half-shaped inserts. Since the use of a shrinkable, flap-shaped core to injection mold a cylindrical cavity structure with an annular groove (even if one side wall of the annular groove is inclined or has spikes) is a technique well-known to those skilled in the art, it will not be described in detail in this application embodiment. Alternatively, as a possible implementation, the outer cylinder 10 may also be manufactured using a 3D printing process. This application embodiment does not limit the manufacturing method of the outer cylinder 10.

[0050] exist Figures 8 to 12 In the various embodiments shown, a plurality of protrusions 15 are formed on the circumferential wall 14a of the inner cavity 14, arranged at uniform intervals along the circumference. In the initial state, as Figure 8 As shown, the circumferential surface of the plunger 20 is in full circumferential sealing contact with the wall surface of the circumferential wall 14a; when the plunger 20 is pushed by the push rod 30 to contact the front side wall 14b of the inner cavity 14 and reach the injection completion position, as... Figures 9 to 12 As shown, the plunger 20 passes over the protrusion 15 and is thus positioned between the protrusion 15 and the front wall 14b of the inner cavity 14. In this way, the drug 60 in the syringe 100 is injected, and the plunger 20 moves to... Figures 9 to 12 At the position shown, if the push rod 30 is pulled backward to retract the plunger 20 and refill the inner cavity 14 with the agent 60, the plunger 20 will not move backward with the push rod 30 because it is blocked and limited by the protrusion 15. Furthermore, the connection between the push rod 30 and the plunger 20 is weak, and the connection force between the push rod 30 and the plunger 20 is less than the blocking force of the protrusion 15 on the plunger 20. Therefore, the plunger 20 will not move backward with the push rod 30; that is, the plunger 20 remains at the position shown. Figures 9 to 12 The injection completion location is shown, thus preventing the syringe 100 from being reused.

[0051] exist Figure 9 and Figure 10 In the illustrated embodiment, the protrusion 15 is formed as a half-sphere (i.e., a hemisphere). Figure 11 and Figure 12 In the embodiment shown, the protrusion 15 is formed as a quarter sphere, having a quarter spherical surface and a planar surface disposed opposite each other in the front-rear direction, with the planar surface located on the front side of the quarter spherical surface. In this way, the plunger 20 can easily pass over the protrusion 15 forward, but it is difficult to pass over the protrusion 15 backward. Figure 10 and 12 The outer cylinder 10 shown can also be manufactured using an injection mold with a retractable flap core, such as a half core comprising multiple half inserts, which will not be described in detail in this application embodiment.

[0052] Please continue reading Figures 1 to 12 and combined Figures 13 to 15 ,exist Figures 1 to 12In the various embodiments shown, the outer cylinder 10 also includes a blocking member 50 detachably mounted at the rear end of the cylinder 11 (more specifically, at the flange 13 at the rear end of the cylinder 11). The blocking member 50 prevents the push rod 30 from completely disengaging from the inner cavity 14 by blocking the plunger push head 32. As mentioned above, for the push rod 30, the cross-sectional dimension of the plunger push head 32 is larger than the cross-sectional dimension of the rod portion 31. Based on this, the blocking member 50 allows the rod portion 31 of the push rod 30 to move back and forth. However, when the larger plunger push head 32 moves backward to the position of the blocking member 50, it will be blocked by the blocking member 50 and cannot pass over the blocking member 50 to disengage from the inner cavity 14 of the outer cylinder 10.

[0053] More specifically, the flange portion 13 has multiple locking holes 13a, and the blocking member 50 has multiple locking protrusions 51 corresponding to the multiple locking holes 13a respectively. The blocking member 50 and the flange portion 13 are detachably installed together through the locking engagement of the locking protrusions 51 and the locking holes 13a. The blocking member 50 is formed into a U-shaped structure with a notch 52. The width of the notch 52 is smaller than the diameter of the plunger push head 32. Therefore, the plunger push head 32 cannot be dislodged from the inner cavity 14 beyond the notch 52.

[0054] like Figure 15 As shown, in the assembled state, the open end of the notch 52 is covered by the flange 13 of the outer cylinder 10, thereby defining the through hole 5a surrounding the rod 31. The cross-section of the through hole 5a and the cross-section of the rod 31 (a cross-section perpendicular to the front-back direction) are formed into corresponding non-circular shapes. Specifically, both cross-sections are approximately rectangular in shape with width and length, and the cross-sectional dimension of the through hole 5a is slightly larger than the cross-sectional dimension of the rod 31. Figures 1 to 12 The width of the cross-section of rod 31 is shown in the figure. The length of the cross-section of rod 31 is perpendicular to the plane of the paper and is not shown in the figure. Figure 13 The perspective view also shows the length and width of the cross-section of the rod 31. With this design, the through hole 5a allows the push rod 30 to move back and forth, but prevents the push rod 30 from rotating. Therefore, it helps to improve the smoothness of the push rod 30's forward movement and can prevent the ball joint 32a on the push rod 30 from separating from the plunger 20 due to accidental rotation of the push rod 30.

[0055] When assembling the syringe 100, the plunger 30 with the plunger 20 installed can be inserted into the inner cavity 14 of the outer cylinder 10. Then, the open end of the notch 52 is aligned with the rod portion 31 and moved along the length direction of the rod portion 31 so that the rod portion 31 of the plunger 30 is received by the notch 52 of the blocking member 50. Then, the blocking member 50 is installed together with the flange portion 13 of the outer cylinder 10 by the snap-fit ​​engagement of the snap-fit ​​protrusion 51 and the snap-fit ​​hole 13a.

Claims

1. A pre-filled syringe for preventing reuse, comprising: An outer cylinder has an inner cavity and a drug outlet located at the front end of the outer cylinder and communicating with the inner cavity. The inner cavity has a circumferential wall and a front side wall, and the drug outlet penetrates the front side wall. The medicine is contained within the cavity. The plunger is slidably housed within the cavity and is made of an elastomer; A push rod is used to push the plunger forward within the cavity to allow the medicine to be discharged from the medicine outlet. The feature is that an annular groove extending in the entire circumferential direction is formed on the circumferential wall, and a protrusion protruding outward from the circumferential surface is formed on the circumferential surface of the plunger. In the initial state, the protrusion is pressed inward by the circumferential wall, and the circumferential surface of the plunger is in sealing contact with the wall surface of the circumferential wall throughout the entire circumference; when the plunger is pushed by the push rod to contact the front side wall, the protrusion is embedded in the annular groove under the action of elastic restoring force.

2. The pre-filled syringe according to claim 1, characterized in that, The push rod engages with the plunger but is not connected. When the push rod is actuated and moves forward, the plunger is pushed by the push rod and moves forward with it. When the push rod is actuated and folds back, the plunger separates from the push rod.

3. The pre-filled syringe according to claim 1, characterized in that, The connection force between the push rod and the plunger is smaller than the engagement force between the protrusion and the annular groove, thereby causing the push rod to separate from the plunger when the push rod is actuated and folds back, in the case where the protrusion is embedded in the annular groove under the action of elastic restoring force.

4. The pre-filled syringe according to claim 3, characterized in that, The push rod has a ball-cutting head that extends forward and is embedded in a groove formed on the rear end face of the plunger.

5. The pre-filled syringe according to any one of claims 1 to 4, characterized in that, The protrusion has a front surface and a rear surface disposed opposite to each other, wherein the front surface is formed as an inclined surface that is inclined rearward in a direction away from the center line of the plunger.

6. The pre-filled syringe according to claim 5, characterized in that, The rear surface is formed as an inclined surface that slopes backward in a direction away from the center line.

7. The pre-filled syringe according to claim 6, characterized in that, The rear wall of the annular groove is formed as an inclined surface that slopes forward in a direction close to the center line.

8. The pre-filled syringe according to claim 6, characterized in that, The rear surface is formed as a vertical surface perpendicular to the center line.

9. The pre-filled syringe according to any one of claims 1 to 4, characterized in that, The annular groove has forward-protruding spikes formed on its rear wall surface.

10. The pre-filled syringe according to any one of claims 1 to 4, characterized in that, The push rod includes a rod portion and a plunger push head integrally formed at the front end of the rod portion; The outer cylinder includes a body defining the inner cavity and a blocking member installed at the rear end of the body, the blocking member preventing the push rod from completely disengaging from the inner cavity by blocking the plunger push head.

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