Rubber stopper

Abstract

To provide a rubber plug capable of suppressing the occurrence of coring.SOLUTION: A rubber plug having a cap part having an upper surface and a lower surface, and a leg part provided on the lower surface of the cap part, the leg part has a tapered base part at the center of a lower surface side of the cap part, and a radius of curvature R1 of the tapered base part is 2 mm or more and 4 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rubber stopper, and more particularly to a rubber stopper capable of suppressing the occurrence of coring. [Background technology]

[0002] Vials and ampoules are containers for storing liquid medicines. Vials are mainly made of glass or plastic pharmaceutical containers, and are sealed by fitting a rubber stopper to the lip. By inserting a needle into the rubber stopper, it can be connected to a syringe or other instrument without opening (or destroying) the container, which allows for hygienic work without accidentally opening the container.

[0003] On the other hand, rubber stoppers applied to the lips of pharmaceutical containers are required to have high quality and physical properties. For example, the quality properties required for rubber stoppers that seal or stop the lips of vials that store antibiotics and other preparations should conform to the Japanese Pharmacopoeia's rubber stopper test for infusions, given their intended use. In addition, it is also necessary to devise a method to prevent coring, a phenomenon in which part of the rubber (rubber piece) that forms the rubber stopper is scraped off when a needle is inserted into the rubber stopper from the needle insertion part.

[0004] For example, Patent Document 1 discloses a rubber stopper for vials that is less susceptible to coring, comprising a lid portion having an upper and lower surface and legs provided on the underside of the lid portion, whereby the needlestick portion in the center of the lid portion is recessed so that the underside of the lid portion is positioned between the upper and lower surfaces of the needlestick portion, and the underside of the cap portion has a flat shape.

[0005] Patent Document 2 also discloses a rubber stopper for a vial which comprises a cap portion having a flange, a puncture area formed with a recess on the top surface of the cap portion and extending vertically from the recess to the bottom surface of the cap portion, and a leg portion formed on the bottom surface of the cap portion so as to protrude downward and outward from the puncture area with respect to the axis of the cap portion, wherein the puncture area is formed from rubber with a rubber hardness of 20 to 35 and the top surface of the cap portion other than the recess is formed from rubber with a rubber hardness of 58 to 90, and which is constructed from multiple materials to reduce coring.

[0006] Furthermore, Patent Document 3 discloses that in a vial and a sealing device used therewith, a sealing member corresponding to a rubber stopper can be easily switched from a semi-stoppering position in which the interior of the vial is connected to the outside space to a sealing position in which that communication is blocked, and that this sealing position can be reliably maintained after sealing, and further that it can be implemented inexpensively with a simple configuration. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-24384 A [Patent Document 2] International Publication No. 2012 / 090328 Brochure [Patent Document 3] JP 2011-50699 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, conventional measures against coring are still insufficient, and the main object of the present invention is to solve the problem of coring. [Means for solving the problem]

[0009] That is, the present invention provides a rubber stopper having a cap portion having an upper surface and a lower surface, and a leg portion provided on the underside of the cap portion, wherein the leg portion has a tapered base at the center of the underside of the cap portion, and the radius of curvature R1 of the tapered base is 2 mm or more and 4 mm or less. In the present invention, the length P of the inner wall of the leg is longer than the length D of the leg itself, and may be more than 100% and less than 160% of the length D of the leg itself. In the present invention, a distance R2 between the start point and the end point of the arc including the apex of the taper base may be 8 mm or less. In the present invention, the cap portion may have a recess in the center of an upper surface side of the cap portion, and an outer diameter R3 of the recess may be 90% or less of the distance R2. In the present invention, the cap portion has a needle piercing portion through which a needle is pierced, and a thickness E of the needle piercing portion may be 60% or more and less than 100% of a thickness C of the cap portion. In the present invention, the thickness E of the needle piercing portion may be 3 mm or less. In the present invention, the thickness E of the needle insertion portion may be 15% or more and 40% or less of the length D of the leg portion itself. In the present invention, the leg portion may have at least one notch. In the present invention, the leg portion may have a ring-shaped protrusion formed on an outer circumferential surface of the leg portion at the tip end side. The rubber stopper according to the present invention may be used to enclose a freeze-dried preparation. Effect of the Invention

[0010] According to the present invention, a rubber stopper capable of suppressing the occurrence of coring can be provided. Note that the effects described here are not necessarily limited to these, and may be any of the effects described in this specification. [Brief description of the drawings]

[0011] [Figure 1]5A is a view for explaining one example of an embodiment of a rubber stopper according to the present invention in a vertical cross section, which is a cross section taken along line PP in FIG. [Diagram 2] FIG. 2 is a diagram illustrating an example of an embodiment of a rubber stopper according to the present invention, viewed from a horizontal lateral direction. [Diagram 3] FIG. 2 is a view illustrating an example of an embodiment of a rubber stopper according to the present invention viewed vertically from above. [Figure 4] FIG. 2 is a view illustrating an example of an embodiment of a rubber stopper according to the present invention viewed vertically from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Preferred embodiments for carrying out the present invention will now be described. The embodiment described below is an example of a typical embodiment of the present invention, and the scope of the present invention is not to be construed as being narrow.

[0013] As shown in Figure 1, the rubber stopper 1 of the present invention has a cap portion 11 having an upper surface and a lower surface, and a leg portion 12 provided on the underside of the cap portion 11, and the leg portion 12 has a substantially hemispherical tapered base portion 10 at the center of the underside of the cap portion, and the radius of curvature R1 of the tapered base portion 10 is 2 mm or more and 4 mm or less.

[0014] In the above-mentioned Patent Document 1, the thickness of the cap and the length of the legs are approximately the same, and the legs are short, so while the problem of coring is solved, there is no mention of a leg shape that can ensure the stability of the rubber stopper when partially stoppered, as in the case of rubber stoppers for freeze-dried preparations, and there is also the problem that the stopper is prone to falling over during transportation. Furthermore, in the above-mentioned Patent Document 2, the rubber stopper is manufactured from a plurality of rubber materials having different hardness, which causes a problem of high manufacturing costs. Furthermore, in the above-mentioned Patent Document 3, a holding member and a protective cover are required when the bottle is in the half-capped position, which increases the number of parts and therefore increases the manufacturing cost.

[0015] Therefore, the present invention has as its main objective the resolution of the problem of coring, and also provides a rubber stopper suitable for freeze-drying, with a leg shape that ensures the stability of the rubber stopper when partially stoppered, like a rubber stopper for freeze-dried preparations, and which can suppress the occurrence of coring even when a single rubber material with the same hardness is used, thereby reducing the number of parts and eliminating manufacturing costs.

[0016] As shown in FIG. 1, the radius of curvature R1 is a radius corresponding to a circular arc including the apex of the tapered base 10. The center point of the radius of curvature R1 is on a perpendicular line (central axis) drawn from the apex of the tapered base 10 toward the center of the leg 12, and the start and end points of the circular arc are defined as "R end portion 1". The "R end portion 1" is a part of the length P of the inner wall of the leg 12. If the radius of curvature R1 is less than 2 mm, the inside of the leg 12 becomes too small, and the hollow needle is likely to scrape the inner wall of the leg 12 and cause coring. If the radius of curvature R1 is more than 4 mm, molding defects are likely to occur in the leg 12.

[0017] The radius of curvature R1 is more preferably 2 mm or more and 3 mm or less.

[0018] As shown in the examples described later, the rubber stopper 1 according to the present invention suppresses the occurrence of coring regardless of whether a plastic needle or a metal needle is used as the needle. In particular, since plastic needles are used in a closed system drug transfer device (CSTD), the rubber stopper 1 according to the present invention can also be used to seal a preparation for the CSTD.

[0019] Examples of materials for forming the rubber stopper 1 according to the present invention include synthetic rubbers such as butyl rubber, isoprene rubber, butadiene rubber, halogenated butyl rubber, ethylene propylene rubber, and silicone rubber, as well as natural rubber. The present invention is also applicable to a so-called laminated rubber stopper, in which a rubber stopper is laminated with a film containing a fluororesin. Examples of the fluororesin include tetrafluoroethylene resin, trifluorochloroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, vinylidene fluoride resin, vinyl fluoride resin, tetrafluoroethylene-ethylene copolymer resin, and trifluorochloroethylene-ethylene copolymer resin. The thickness of the film to be laminated can be, for example, 0.002 mm or more and 0.5 mm or less. The hardness of the rubber stopper 1 according to the present invention is, for example, 25 to 45, and preferably 28 to 40.

[0020] In the present invention, the length P of the inner wall of the leg 12 (the length from the apex of the tapered base 10 to the point of the R-stop portion 2 that becomes flat on the ground side of the leg 12 (at the inner tip of the leg 12) (see A in Figure 1)) is longer than the length D of the leg 12 itself (the shortest distance from the underside of the cap portion to the flat plane on the ground side of the leg 12 (see A in Figure 1)), and is preferably more than 100% but less than 160%, and more preferably more than 100% but less than 145%, of the length D of the leg 12 itself. This makes it possible to prevent molding defects such as film tearing caused by the film being stretched too much when laminating the leg 12.

[0021] In the present invention, the distance R2 between the start point and the end point of the arc including the apex of the tapered base 10 is preferably 8 mm or less, more preferably 6 mm or less. If the distance R2 exceeds 10 mm, the moldability is poor and the film is difficult to attach to the leg. If the distance R2 is less than 4 mm, the inner wall surface is easily scraped by the center needle and coring is easily caused. The distance R2 is the chord length of the arc including the apex of the tapered base 10 extending a horizontal line in the radial direction from the point of the "R stop portion 1" as shown in FIG. 1. The positions of the start point and the end point of the "R stop portion 1" can be determined by the position of the outer diameter R3 of the recess 111 described later and the required length D of the leg 12 itself. Furthermore, the positions of the start point and the end point of the "R stop portion 1" can be determined at the same height as the outer diameter position of the annular protrusion B provided on the underside of the cap portion as shown in FIG. 1, or within a range of the height of the outer diameter position of the annular protrusion B ±10%.

[0022] In addition, it is preferable that the "R stop portion 1" is present on a tangent line extending toward the central axis (line) at the "R stop portion 2 (R stop portion 1 side)" at the inner end of the leg. In addition, by having an inclination on the tangent line connecting the "R stop portion 1" and the "R stop portion 2 (R stop portion 1 side)" at the end of the inner wall of the leg, the overall length of the leg 12 is shortened and the volume of the leg 12 is increased, thereby improving the stability of the leg 12 and thus the stability of the entire rubber stopper 1. In addition, coring is unlikely to occur even if not only a metal needle but also a hollow needle such as a plastic needle with a diameter larger than a metal needle is inserted obliquely, and the occurrence of coring can be avoided. As shown in Fig. 1, "R end portion 2" has two points on a curve provided at the inner end of the leg, and consists of a flat point on the ground side of leg 12 (at the inner end of leg 12) and a point on the "R end portion 1" side. In the present invention, the radius of curvature of the curve connecting the two points of "R end portion 2" is preferably 0.1 to 1.0 mm, and particularly preferably about 0.5 mm.

[0023] The relationship between the radius of curvature R1 and the distance R2 is 2R1>R2 or 2R1=R2. Furthermore, the radius of curvature R1 and the distance R2 are between the center of the underside of the cap and a height (position) of D / 2 or more from the tip of the leg, as shown in FIG.

[0024] 1 and 3, the cap portion 11 has a recess 111 at the center of the upper surface of the cap portion, and the outer diameter R3 of the recess 111 is preferably 90% or less of the distance R2, thereby making it possible to further suppress the occurrence of coring.

[0025] The cap portion 11 has a recess 111 at the center of the top surface thereof, and has a needle piercing portion 112 which is the bottom surface of the recess 111 and into which the needle is pierced, and the thickness E of the needle piercing portion 112 is preferably 60% or more and less than 100% of the cap portion thickness C. By making it 60% or more, it is possible to prevent the needle piercing portion 112 from becoming too thin and being damaged, which can cause leakage of the drug solution, etc. Also, by making it less than 100%, it is possible to further suppress the occurrence of coring.

[0026] In this case, the thickness E of the needle puncture portion 112 is preferably 3 mm or less. If the thickness E of the needle puncture portion 112 exceeds 3 mm, the risk of coring increases. Furthermore, the needle puncture resistance increases when the needle is punctured. Although there is no particular limit to the lower limit of the thickness E of the needle puncture portion 112, it is preferably 1 mm or more in order to maintain the self-sealing property and barrier property.

[0027] In this case, the thickness E of the needle piercing portion is preferably 15% to 40% of the length D of the leg portion 12 itself. By making it 15% or more, it is possible to prevent the needle piercing portion 112 from becoming too thin and being damaged, which may cause leakage of the drug solution, etc. Also, by making it 40% or less, it is possible to reduce the risk of coring.

[0028] As shown in FIG. 4, the leg 12 preferably includes a circular tapered base 10 having the same diameter as the needle piercing portion 112 in the center, and has a notch 13 so that more than half of the circumference of the tapered base 10 is open. By having one notch 13, the contact area with the inner wall of the lip during half-stoppering is larger than in the case where the leg 12 has two notches and a bifurcated structure, so that the occurrence of slippage or dislodging of the rubber stopper 1 can be suppressed. In addition, the leg 12 remains standing upright to fit the lip of the vial during half-stoppering, and at that time, the protrusion 121 provided on the outer peripheral surface of the leg 12 is firmly in contact with the inner wall of the lip so that the rubber stopper 1 does not come off from the vial, and the rubber stopper 1 can be fixed. Therefore, the rubber stopper 1 according to the present invention can be used for a freeze-dried preparation, and is stable even during half-stoppering. Furthermore, by providing the notch 13 at one location, the rubber stopper 1 itself can easily stand on its own, preventing the rubber stopper 1 from falling over during transportation and preventing the legs 12 from docking together.

[0029] The method for filling a lyophilized preparation into a pharmaceutical container is generally carried out in the following order of (a) to (c). (a) The formulation is aseptically filled into the pharmaceutical container body. (b) Next, a rubber stopper is half-sealed onto the lip of the pharmaceutical container body to prevent the inclusion of foreign matter, and the container is then freeze-dried in a freeze-dryer. (c) After freeze-drying, completely seal the vials and remove them from the freeze-dryer.

[0030] 2 and 4, it is preferable that a tapered, ring-shaped protrusion 121 is formed on the outer circumferential surface of the tip of the leg 12. With this, during the partial stoppering in the above step (B), the tapered narrowing acts as a guide against the inner wall surface of the lip of the pharmaceutical container body, allowing smooth partial stoppering, and the contact area with the inner wall surface of the lip is increased, so that the rubber stopper 1 is stably and firmly fixed and fitted to the pharmaceutical container. EXAMPLES

[0031] The present invention will now be described in more detail with reference to the embodiment shown in FIG. The embodiment described below is a representative example of the present invention. This should not be construed as narrowing the scope of the present invention.

[0032] <Test Example 1> The rubber stoppers of Examples 1 and 2 were fitted into pharmaceutical containers for freeze-dried preparations, and the number of corings that occurred was investigated using various needles shown in Table 1 below.

[0033] [Example 1] A rubber stopper 1 made of chlorinated butyl rubber coated with a fluorine-based resin was prepared as shown in FIG. 1, which has a cap portion 11 having an upper surface and a lower surface, and a leg portion 12 provided on the lower surface of the cap portion 11, and the leg portion 12 has a tapered base portion 10 at the center of the cap lower surface side, and the radius of curvature R1 of the tapered base portion 10 is 2.65 mm. The length P of the inner wall of the leg portion 12 of the rubber stopper 1 is the length from the center of the cap lower surface on the central axis to the "R stop portion 2" where the tip of the inner wall of the leg becomes flat, and was 13.3 mm. The length D of the leg portion 12 itself was 10.2 mm. In addition, the distance R2 of the leg portion 12 on the cap lower surface side was 4.6 mm. Furthermore, the cap portion 11 has a recess 111 at the center of the cap upper surface side, and the outer diameter R3 of the recess 111 was 4.0 mm. Moreover, the cap portion 11 had a needle insertion portion 112 into which a needle was inserted, and the thickness E of the needle insertion portion 112 was 2.5 mm.

[0034] [Example 2] A rubber stopper 1 made of chlorinated butyl rubber coated with a fluorine-based resin was prepared as shown in FIG. 1, which has a cap portion 11 having an upper surface and a lower surface, and a leg portion 12 provided on the lower surface of the cap portion 11. The leg portion 12 has a tapered base portion 10 at the center of the cap lower surface side, and the radius of curvature R1 of the tapered base portion 10 is 3.30 mm. The length P of the inner wall of the leg portion 12 of the rubber stopper 1 is the length from the center of the cap lower surface on the central axis to the "R stop portion 2" where the tip of the inner wall of the leg becomes flat, and was 13.2 mm. The length D of the leg portion 12 itself was 10.3 mm. In addition, the distance R2 of the leg portion 12 on the cap lower surface side was 5.3 mm. However, in this Example 2, the cap portion 11 does not have a recess 111 at the center of the cap upper surface side. Moreover, the cap portion 11 had a needle insertion portion 112 into which a needle was inserted, and the thickness E of the needle insertion portion 112 was 3.3 mm.

[0035] The test results are shown in Table 1 below.

[0036] [Table 1]

[0037] The results of this test example 1 suggest that the occurrence of coring can be suppressed by using the rubber stopper 1 according to the present invention, which has a cap portion 11 having an upper surface and a lower surface, and a leg portion 12 provided on the lower surface of the cap portion 11, the leg portion 12 having a tapered base portion 10 at the center of the lower surface side of the cap portion, and the radius of curvature R1 of the tapered base portion 10 being 2 mm or more and 4 mm or less. Furthermore, as shown in Table 1 above, the rubber stopper 1 according to the present invention had little occurrence of coring regardless of whether a plastic needle or a metal needle was used. Furthermore, it was found that the occurrence of coring can be further suppressed by setting the thickness E of the needle piercing portion 112 to 3 mm or less. [Industrial Applicability]

[0038] As is clear from the above, according to the present invention, the problem of coring can be solved, and the present invention can provide a rubber stopper suitable for freeze-drying with a leg shape that ensures the stability of the rubber stopper at the time of partial stoppering, such as a rubber stopper for freeze-dried preparations, and can suppress the occurrence of coring even when a single rubber material with the same hardness is used, thereby reducing the number of parts and reducing manufacturing costs. [Explanation of symbols]

[0039] 1 Rubber stopper 10 Tapered base 11 Kasabe 111 Recess 112 Needle insertion part 12 Legs 121 Convex 13 Cutout R1 Radius of curvature at the base of the taper R2: The distance between the start and end points of the arc containing the vertex of the taper base R3 Outer diameter of recess B. Annular protrusion C Thickness of cap D Length of the leg itself E Thickness of needle insertion part

Claims

1. A cap portion having an upper surface and a lower surface; A rubber stopper having a leg portion provided on the underside of the cap portion, The leg portion has a tapered base portion at the center of the lower surface side of the cap portion, The tapered base has a radius of curvature R1, The radius of curvature R1 is a radius corresponding to an arc including a vertex of the taper base portion, The center point of the radius of curvature R1 is on a perpendicular line drawn from the apex of the tapered base toward the center of the leg, and when the start point and end point of the arc are R end portion 1, there are two R end portions 2 on a curve drawn from the R end portion 1 toward the tip side of the leg, The two R-stop portions 2 have a point on the R-stop portion 1 side and a flat point at the inner tip of the leg portion, and The R-stop portion 1 is a rubber plug that exists on a tangent line extending toward the central axis on the R-stop portion 1 side of the inner tip of the leg portion.

2. A rubber stopper as described in claim 1, wherein the length P of the inner wall of the leg is longer than the length D of the leg itself and is more than 100% but less than 160% of the length D of the leg itself.

3. 3. The rubber stopper according to claim 1, wherein a radius of curvature of a curve connecting the two R-stop portions 2 is 0.1 to 1.0 mm.

4. A rubber stopper described in any one of claims 1 to 3, wherein a distance R2 between the start point and end point of an arc including the apex of the tapered base is 4 mm or more.

5. A rubber stopper as described in any one of claims 1 to 4, wherein a distance R2 between the start point and end point of an arc including the apex of the tapered base is 8 mm or less.

6. The cap portion has a recess in the center of an upper surface side of the cap portion, 6. The rubber plug according to claim 4, wherein an outer diameter R3 of the recess is 90% or less of the distance R2.

7. The cap portion has a needle piercing portion through which a needle is pierced, 7. The rubber stopper according to claim 1, wherein a thickness E of the needle piercing portion is 60% or more and less than 100% of a thickness C of the cap portion.

8. A rubber stopper as described in claim 7, wherein the thickness E of the needle insertion portion is 3 mm or less.

9. A rubber stopper as described in claim 7 or 8, wherein the thickness E of the needle insertion portion is greater than or equal to 15% and less than or equal to 40% of the length D of the leg portion itself.

10. A rubber stopper described in any one of claims 1 to 9, wherein the leg portion has at least one notch.

11. A rubber stopper as described in Claim 10, wherein the leg has a ring-shaped protrusion formed on the outer peripheral surface of the tip side of the leg.

12. A rubber stopper described in any one of claims 1 to 11, used to encapsulate a freeze-dried preparation.

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