rubber stopper

Abstract

Provided is a rubber plug that inhibits core removal. The rubber plug is characterized by including: a cap portion having an upper surface and a lower surface; and a foot portion provided on the lower surface of the cap portion; the foot portion has a tapered base portion in the center of the lower surface of the cap portion; and the radius of curvature R1 of the tapered base portion is 2 mm or more and 4 mm or less.

Description

Technical Field

[0001] This invention relates to a rubber plug. More specifically, it relates to a rubber plug capable of suppressing coring. Background Technology

[0002] As containers for storing liquid medicines, there are vials and ampoules. Vials are mainly sealed by plugging the opening of a medical container such as glass or plastic with a rubber stopper. Even without opening (or breaking) the container, it can be connected to instruments such as syringes by inserting a needle into the rubber stopper, so the container can be opened hygienically and operations can be carried out without accident.

[0003] On the other hand, rubber stoppers used in the openings of pharmaceutical containers are required to possess high quality and physical properties. For example, rubber stoppers used to seal or plug the openings of vials containing antibiotics and other preparations must meet the quality characteristics required by the Japanese Pharmacopoeia for infusion rubber stoppers in their intended use. Furthermore, the design must be optimized to prevent the removal of a portion of the rubber forming the stopper (the rubber sheet) when a needle is inserted into the stopper (core removal).

[0004] For example, Patent Document 1 discloses a rubber stopper for a small bottle, which includes a cap having an upper surface and a lower surface, and a foot provided on the lower surface of the cap. The needle-like portion in the center of the cap is recessed such that the lower surface of the cap is located between the upper and lower surfaces of the needle-like portion, and the lower surface of the cap is flat, thereby reducing the amount of core removal.

[0005] In addition, Patent Document 2 discloses a rubber plug for a vial, which includes a cap with a flange, a puncture area formed in such a way that a recess is formed on the top surface of the cap and extends longitudinally from the recess to the bottom surface of the cap, and a foot formed at a position further outward relative to the axis of the cap than the puncture area and with the bottom surface of the cap protruding downward. The puncture area is formed of rubber with a hardness of 20 to 35, and the top surface of the cap other than the recess is formed of rubber with a hardness of 58 to 90. By being made of multiple materials, the amount of core removal is reduced.

[0006] In addition, Patent Document 3 discloses a vial and a sealing device used on the vial, wherein the sealing component, which is equivalent to a rubber plug, can be easily switched from a semi-inserted position where the vial's housing is connected to the external space to a sealed position where the connection is blocked. After sealing, the sealed position can be reliably maintained, and it can be implemented economically with a simple configuration.

[0007] [Existing Technical Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2004-24384

[0009] [Patent Document 2] International Publication No. 2012 / 090328

[0010] [Patent Document 3] Japanese Patent Application Publication No. 2011-50699 Summary of the Invention

[0011] [The problem the invention aims to solve]

[0012] However, the existing countermeasures for core removal are insufficient. Therefore, the main objective of this invention is to solve the problem of core removal.

[0013] [Technical means to solve the problem]

[0014] That is, the present invention provides a rubber plug, characterized in that it comprises: a cap having an upper surface and a lower surface; and a foot disposed on the lower surface of the cap; the foot having a conical base at the center of the lower surface side of the cap; the radius of curvature R1 of the conical base being 2 mm or more and 4 mm or less; the cap having a recess at the center of the upper surface side of the cap; the outer diameter R3 of the recess being 90% or less of the distance R2 between the start and end points of the arc containing the vertex of the conical base.

[0015] In this invention, the length P of the inner wall of the foot can be longer than the length D of the foot itself, and is more than 100% and less than 160% of the length D of the foot itself.

[0016] In this invention, the distance R2 can be less than 8mm.

[0017] In this invention, the cap may have a needle-punching portion for needle puncture; the thickness E of the needle-punching portion is more than 60% and less than 100% of the thickness C of the cap.

[0018] In this invention, the thickness E of the needle-punched portion can be less than 3 mm.

[0019] In this invention, the thickness E of the needle-piercing portion can be 15% to 40% or less relative to the length D of the foot itself.

[0020] In this invention, the foot may have at least one notch.

[0021] In this invention, the foot may have an annular protrusion formed on the outer peripheral surface of the front end side of the foot.

[0022] The rubber plug of the present invention can be used for sealing lyophilized formulations.

[0023] [The effects of the invention]

[0024] According to the present invention, a rubber plug capable of suppressing core removal can be provided.

[0025] Furthermore, the effects described herein are not necessarily limited to these, and can be any of the effects described in this specification. Attached Figure Description

[0026] Figure 1 Figure (A) in the figure illustrates an example of an embodiment of the rubber plug of the present invention using a vertical cross-section, and is... Figure 4 PP line section view. Figure 1 (B) in the middle is Figure 1 A magnified view of (A) in the image.

[0027] Figure 2 This is a diagram illustrating an example of an embodiment of the rubber plug of the present invention from a horizontal direction.

[0028] Figure 3 This is a diagram illustrating an example of an embodiment of the rubber plug of the present invention from a vertical perspective.

[0029] Figure 4 This is a diagram illustrating an example of an embodiment of the rubber plug of the present invention from a vertical perspective. Detailed Implementation

[0030] The preferred embodiments for carrying out the present invention will be described below.

[0031] The embodiments described below are examples of representative embodiments of the present invention and are not intended to narrow the scope of the invention.

[0032] like Figure 1 As shown, the rubber plug 1 of the present invention is characterized in that it comprises: a cap 11 having an upper surface and a lower surface; and a foot 12 disposed on the lower surface of the cap 11; the foot 12 has a generally hemispherical conical base 10 at the center of the lower surface side of the cap, the radius of curvature R1 of the conical base 10 being more than 2 mm and less than 4 mm.

[0033] In the aforementioned patent document 1, the thickness of the cap is approximately the same as the length of the foot. Because the length of the foot is short, although the problem of removing the core is solved, it cannot be said to be a foot shape that can ensure the stability of the rubber plug when it is partially plugged in, like the rubber plug used in freeze-dried preparations. Moreover, there is a problem that it is easy to tip over during transportation.

[0034] In addition, in the aforementioned Patent Document 2, the rubber plug is made of various rubber materials with different hardness, which increases the manufacturing cost.

[0035] Furthermore, in the aforementioned patent document 3, a retaining component or protective cover is required when in a half-clamping position, which increases the number of parts and thus raises the issue of increased manufacturing costs.

[0036] Therefore, while the present invention aims to solve the problem of core removal, it also provides a rubber plug with a foot shape that ensures the stability of the rubber plug when it is partially plugged, similar to the rubber plug used in freeze-dried preparations. Even if a single rubber material with the same hardness is used, core removal can be suppressed, the number of parts can be reduced, the manufacturing cost can be reduced, and it is also suitable for freeze-drying.

[0037] like Figure 1 As shown, the radius of curvature R1 is the radius corresponding to the arc containing the vertex of the conical base 10. Furthermore, the center point of the radius of curvature R1 is located on a vertical line (central axis) falling from the vertex of the conical base 10 towards the center of the foot 12. The start and end points of this arc are defined as the "first rounded corner stop." The "first rounded corner stop" is a portion of the length P of the inner wall of the foot 12. When the radius of curvature R1 is less than 2 mm, the inner side of the foot 12 is too small, increasing the likelihood of the hollow needle cutting away the inner wall of the foot 12 and causing core removal. Additionally, when the radius of curvature R1 exceeds 4 mm, the foot 12 is prone to molding defects.

[0038] The radius of curvature R1 is more preferably 2 mm or more to 3 mm or less.

[0039] As shown in the embodiments described later, the rubber plug 1 of the present invention suppresses core removal when using either a plastic needle or a metal needle. In particular, since plastic needles are used in Closed System Drug Transfer Devices (CSTDs), the rubber plug 1 of the present invention can also be used to seal CSTD formulations.

[0040] Examples of materials used to form the rubber plug 1 of the present invention include, for example, synthetic rubbers or natural rubbers such as butyl rubber, isoprene rubber, butadiene rubber, halogenated butyl rubber, ethylene propylene rubber, and silicone rubber. The present invention can also be applied to, for example, so-called laminated rubber plugs formed by laminating a film containing a fluorinated resin. Examples of such fluorinated resins include, for example, tetrafluoroethylene resin, trifluorochloroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, vinylidene fluoride resin, fluorinated vinyl resin, tetrafluoroethylene-ethylene copolymer resin, and trifluorochloroethylene-ethylene copolymer resin. The thickness of the laminated film can be, for example, set to 0.002 mm or more and 0.5 mm or less. Furthermore, the hardness of the rubber plug 1 of the present invention is, for example, 25 to 45, preferably 28 to 40.

[0041] In this invention, the length P of the inner wall of the foot 12 (from the apex of the conical base 10 to the point in the second rounded corner stop where the foot 12 becomes flat on the ground-contacting side (the inner front end of the foot 12)) is defined as (refer to...). Figure 1(A) is longer than the length D of the foot 12 itself (the shortest distance from the lower surface of the cap to the plane that becomes flat on the ground side of the foot 12 (refer to)). Figure 1 In (A), it is preferable that the length D relative to the foot 12 itself is more than 100% and less than 160%, more preferably more than 100% and less than 145%. Thus, the film will not be overstretched when the foot 12 is laminated, and molding defects such as film breakage can be prevented.

[0042] In this invention, the distance R2 between the start and end points of the arc comprising the apex of the conical base 10 is preferably 8 mm or less, more preferably 6 mm or less. If the distance R2 exceeds 10 mm, the formability is poor, and it is difficult to attach the film to the foot. Furthermore, if the distance R2 is less than 4 mm, the inner wall surface is easily chipped away by the center pin, and core removal is likely to occur. Additionally, as... Figure 1 As shown, the distance R2 is the chord length of the arc including the vertex of the conical base 10, obtained by drawing a horizontal line radially from the point of the "first rounded corner stop". Furthermore, the positions of the start and end points of the "first rounded corner stop" can be determined by the position of the outer diameter R3 of the recess 111 (described later) and the required length D of the foot 12 itself. Additionally, as... Figure 1 As shown, the starting and ending points of the "first rounded corner stop" can be set at the same height as the outer diameter of the annular protrusion B on the lower surface of the cap, or within ±10% of the height of the outer diameter of the annular protrusion B.

[0043] Furthermore, the "first rounded corner stop" preferably exists on a tangent extending toward the central axis at the "second rounded corner stop (first rounded corner stop side)" at the front end of the inner side of the foot. Moreover, by tilting the tangent connecting the "first rounded corner stop" to the "second rounded corner stop (first rounded corner stop side)" at the front end of the inner wall of the foot, the overall length of the foot 12 is shortened, while the volume of the foot 12 increases, thereby improving the stability of the foot 12 and thus improving the overall stability of the rubber plug 1. In addition, not only metal needles, but even hollow needles such as plastic needles with a diameter larger than metal needles are less likely to be cored when tilted during insertion, thus preventing core removal.

[0044] In addition, such as Figure 1 As shown, the "second rounded corner stop" has two points on the curve located at the inner front end of the foot, including the point where the foot 12 flattens out on the ground contact side (inner front end of the foot 12) and the point on the "first rounded corner stop" side. In this invention, the radius of curvature of the curve connecting the two points of the "second rounded corner stop" is preferably 0.1 to 1.0 mm, and particularly preferably about 0.5 mm.

[0045] Furthermore, the relationship between the radius of curvature R1 and the distance R2 is 2R1 > R2 or 2R1 = R2. Additionally, as... Figure 1 As shown, the radius of curvature R1 and the distance R2 are located between the center of the lower surface of the hat and a height (position) greater than D / 2 from the front end of the foot.

[0046] like Figure 1 and Figure 3 As shown, the cap portion 11 has a recess 111 at the center of its upper surface side, and the outer diameter R3 of the recess 111 is preferably 90% or less relative to the distance R2. This further suppresses the occurrence of core removal.

[0047] The cap portion 11 has a recess 111 at the center of its upper surface and a needle-piercing portion 112 serving as the bottom surface of the recess 111 for needle puncture. The thickness E of the needle-piercing portion 112 is preferably 60% or more and less than 100% of the thickness C of the cap portion. By setting it to 60% or more, damage to the needle-piercing portion 112 due to excessive thinness, such as leakage of the medication, can be prevented. Furthermore, by setting it to less than 100%, the occurrence of core removal can be further suppressed.

[0048] At this point, the thickness E of the needle-punched portion 112 is preferably 3 mm or less. If the thickness E of the needle-punched portion 112 exceeds 3 mm, the risk of core removal increases. Moreover, the needle puncture resistance during needle penetration also increases. There is no particular limitation on the lower limit of the thickness E of the needle-punched portion 112, but in order to maintain self-sealing and barrier properties, it is preferably 1 mm or more.

[0049] Furthermore, at this time, the thickness E of the needle portion relative to the length D of the foot portion 12 itself is preferably 15% to 40% or less. By setting it to 15% or more, damage to the needle portion 112 due to excessive thinness, such as leakage of the medicine, can be prevented. Moreover, by setting it to 40% or less, the risk of core removal can be suppressed.

[0050] like Figure 4As shown, the foot 12 preferably includes a circular conical base 10 with the same diameter as the needle portion 112 at its center, and has a notch 13 that is open at more than half of the circumference of the conical base 10. By having only one notch 13, compared to a case where the foot 12 has two notches and a bifurcated structure, the contact area with the inner wall of the opening is increased when partially stoppered, thus suppressing the displacement or detachment of the rubber plug 1. Furthermore, when partially stoppered, the foot 12 is in an upright state adapted to the opening of the vial, and the protrusion 121 on the outer circumferential surface of the foot 12 is firmly and tightly connected to the inner wall of the opening, securing the rubber plug 1 and preventing it from falling out of the vial. Therefore, the rubber plug 1 of the present invention can be used in lyophilized formulations and exhibits stability even when partially stoppered. In addition, by having a notch 13, the rubber plug 1 can easily stand upright, which can also prevent the rubber plug 1 from falling down or the feet 12 from sticking together during transportation.

[0051] In addition, the method of filling the lyophilized preparation into the pharmaceutical container is usually carried out in the following order (a) to (c).

[0052] (a) Aseptically fill the formulation into the body of the pharmaceutical container.

[0053] (b) Then, freeze-drying is performed in a freeze dryer with the opening of the main body of the pharmaceutical container partially plugged with a rubber stopper to prevent foreign matter from entering.

[0054] (c) After freeze-drying, completely seal the freeze dryer and remove it from the freeze dryer.

[0055] like Figure 2 and Figure 4 As shown, the foot 12 preferably has a tapered and annular protrusion 121 formed on the outer peripheral surface of the front end side of the foot. Thus, during the partial plugging in step (b), the tapered narrowing portion guides the smooth partial plugging of the inner wall of the opening of the pharmaceutical container body, and increases the contact area with the inner wall of the opening, so that the rubber plug 1 is stably and firmly fixed and thus fitted into the pharmaceutical container.

[0056] Example

[0057] The following is based on Figure 1 The embodiments shown illustrate the invention in more detail. Furthermore, the embodiments described below represent one example of a representative embodiment of the invention and are not intended to narrow the scope of the invention.

[0058] <Experimental Example 1>

[0059] The number of plugs used to seal the containers for lyophilized pharmaceutical preparations in Examples 1 and 2 was investigated using the various plugs shown in Table 1 below for the occurrence of core removal.

[0060] [Example 1]

[0061] Preparation Figure 1 The illustrated rubber plug 1, made of chlorinated butyl rubber coated with fluorinated resin, comprises: a cap 11 having an upper surface and a lower surface; and a foot 12 disposed on the lower surface of the cap 11. The foot 12 has a conical base 10 at the center of the lower surface side of the cap, the radius of curvature R1 of the conical base 10 being 2.65 mm. The length P of the inner wall of the foot 12 of the rubber plug 1 is 13.3 mm, from the center of the lower surface of the cap located on the central axis to the "second rounded stop" at the point where the inner wall of the foot becomes flat at the front end. The length D of the foot 12 itself is 10.2 mm. Furthermore, the distance R2 of the foot 12 on the lower surface side of the cap is 4.6 mm. In addition, the cap 11 has a recess 111 at the center of the upper surface side of the cap, the outer diameter R3 of the recess 111 being 4.0 mm. Furthermore, the cap 11 has a needle-piercing portion 112 for needle piercing, and the thickness E of the needle-piercing portion 112 is 2.5 mm.

[0062] [Example 2]

[0063] Preparation Figure 1 The illustrated rubber plug 1, made of chlorinated butyl rubber coated with fluorinated resin, comprises: a cap 11 having an upper surface and a lower surface; and a foot 12 disposed on the lower surface of the cap 11. The foot 12 has a conical base 10 at the center of the lower surface side of the cap, the radius of curvature R1 of the conical base 10 being 3.30 mm. The length P of the inner wall of the foot 12 of the rubber plug 1 is 13.2 mm, from the center of the lower surface of the cap located on the central axis to the "second rounded stop" at the point where the inner wall of the foot becomes flat at the front end. The length D of the foot 12 itself is 10.3 mm. Moreover, the distance R2 of the foot 12 on the lower surface side of the cap is 5.3 mm. However, in this embodiment 2, the cap 11 does not have a recess 111 at the center of the upper surface side of the cap. In addition, the cap 11 has a needle-piercing portion 112 for needle piercing, and the thickness E of the needle-piercing portion 112 is 3.3 mm.

[0064] The test results are shown in Table 1 below.

[0065] [Table 1]

[0066]

[0067] The results of this test example 1 show that core removal can be suppressed by using the rubber plug 1 of the present invention. The rubber plug 1 is characterized by comprising: a cap 11 having an upper surface and a lower surface; and a foot 12 disposed on the lower surface of the cap 11; the foot 12 has a conical base 10 at the center of the lower surface side of the cap, the radius of curvature R1 of the conical base 10 being 2 mm or more and 4 mm or less. Furthermore, as shown in Table 1, it can be seen that the rubber plug 1 of the present invention results in less core removal when using either plastic or metal needles. In addition, it can be seen that by setting the thickness E of the needle insertion portion 112 to 3 mm or less, core removal can be further suppressed.

[0068] [Industrial Applicability]

[0069] As can be seen from the above, the present invention can solve the problem of core removal and provide the following rubber plug: it is designed with a foot shape that ensures the stability of the rubber plug when it is partially plugged, similar to the rubber plug for freeze-dried preparations. Even if a single rubber material with the same hardness is used, core removal can be suppressed, the number of parts can be reduced, the manufacturing cost can be reduced, and it is also suitable for freeze-drying.

[0070] In the picture:

[0071] 1: Rubber plug

[0072] 10: Conical base

[0073] 11: Hat section

[0074] 111: concave part

[0075] 112: Acupuncture point

[0076] 12: Feet

[0077] 121:convex part

[0078] 13: Gap

[0079] R1: Radius of curvature of the conical base

[0080] R2: The distance between the start and end points of the arc containing the vertex of the cone base.

[0081] R3: outer diameter of the recess

[0082] B: Ring-shaped protrusions

[0083] C: Thickness of the cap

[0084] D: The length of the foot itself

[0085] E: Thickness of the needle-punched area.

Claims

1. A rubber plug, characterized by, Comprising: a cap portion having an upper surface and a lower surface; and a foot portion provided on the lower surface of the cap portion; the foot portion has a tapered base portion in the center of the lower surface of the cap portion; the radius of curvature of the tapered base portion is 2 mm or more and 4 mm or less; the cap portion has a recess in the center of the upper surface of the cap portion; the distance of the outer diameter of the recess from the start point to the end point of the circular arc including the vertex of the tapered base portion is 90% or less.

2. A rubber plug according to claim 1, characterised in that The length of the inner wall of the foot portion is longer than the length of the foot portion itself, and exceeds 100% and is less than 160% with respect to the length of the foot portion itself.

3. A rubber plug according to claim 2, characterised in that The distance is 8 mm or less.

4. A rubber plug according to any one of claims 1 to 3, characterised in that The cap portion has a needle puncture portion for needle puncture; The thickness of the needle puncture portion is 60% or more and less than 100% of the thickness of the cap portion.

5. A rubber plug according to claim 4, characterised in that The thickness of the needle puncture portion is 3 mm or less.

6. A rubber plug according to claim 4, characterised in that The thickness of the needle puncture portion is 15% or more and 40% or less with respect to the length of the foot portion itself.

7. A rubber plug according to any one of claims 1 to 3, characterised in that The foot portion has at least one notch.

8. A rubber plug according to claim 7, characterised in that The foot portion has an annular protrusion formed on the outer peripheral surface of the front end side of the foot portion.

9. A rubber plug according to any one of claims 1 to 3, characterised in that Encapsulation for freeze-dried preparations.

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