JP2004033509A - Plunger rod for injection syringe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plunger rod for an injection syringe capable of extremely easily separating waste after administration from a gasket after several days are elasped following the adminitration of a medicinal liquid when a plunger rod is fractionally discarded for the purpose of reducing the amount of the waste after the administration in a syringe preliminarily filled with a general medicine or a radioactive medine. <P>SOLUTION: In a medical syringe comprising a cylinder, a gasket and a plunger rod, a resin which is selected from fluoroplastic, a silicone resin, a polyethylene resin and a polypropylene resin is provided to at least a part of the bonding surfaces of the gasket and the plunger rod. <P>COPYRIGHT: (C)2004,JPO

Description

【００１１】
【発明の効果】
以上のように、医療用シリンジに用いられる本発明プランジャーロッドは、ガスケットとの接合面を摩擦抵抗の小さい樹脂で被覆されているので、両者の密着が防止され、分離性が維持されている。これにより、通常取り外しが困難となる投与後数日放置されたシリンジにおいても極めて容易かつ確実にプランジャーロッドを取り外して分別廃棄することが可能となる。
【図面の簡単な説明】
【図１】本発明プランジャーロッドとガスケットとの螺合状態を示す要部拡大軸方向断面説明図。
【図２】従来および本発明タングステンプランジャーロッド例（雄ネジ部の形状が略三角柱状）を示す概略斜視説明図。
従来品　：雄ネジ部１２を含む先部２１にフッ素樹脂を被覆しない。
本発明品：雄ネジ部１２を含む先部２１にフッ素樹脂を被覆する。
【図３】従来のタングステンプランジャーロッド例（雄ネジ部の形状が円柱状）を示す概略斜視説明図。
従来品　：雄ネジ部１２を含む先部２１にフッ素樹脂を被覆しない。
本発明品：雄ネジ部１２を含む先部２１にフッ素樹脂を被覆する。
【図４】従来のプラスチックプランジャーロッド例を示す概略斜視説明図。
【符号の説明】
１０；プランジャーロッド
１１；先部端面
１２；雄ネジ部
１３；シリンジ
１４；ガスケット
１５；雌ネジ部
２０；放射線遮蔽先部
２１；先部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plunger rod for an injection syringe body.
[0002]
[Prior art]
At medical sites in recent years, drug-filled syringes that can be transported and stored with the drug solution pre-filled inside the syringe, attach the injection needle at the time of administration, and then push the plunger rod to administer the drug. Has come to be used frequently. In many of them, a so-called disposable set in which an empty syringe and a plunger rod are separately discarded after the liquid medicine inside the syringe is used up is generally used. And the method of joining the plunger rod to the gasket in the injection syringe filled with the drug solution is often a screw type, a fitting type, an adhesive type and an integral molding type, but when a separation operation after administration is required, Many screw types that are easy to separate are used.
[0003]
In the case of radiopharmaceuticals, for the purpose of minimizing the amount of radioactive waste, after using a syringe, it is desirable to separate the syringe to which the radioactive substance is attached from the plunger rod to which it is not attached and discard them separately. I have. Further, when a special plunger rod having a radiation shielding ability is used, it is expensive, and therefore it is usually used repeatedly instead of disposable for economic reasons. When a conventional screw-type plunger rod is used, after filling the filled chemical solution, when separating and disposing of the syringe and the plunger rod, when rotating to remove the plunger rod, the gasket and the inner wall of the syringe are used. When the frictional force between the plunger rod and the gasket is greater than the frictional force with the plunger rod, the gasket rotates in close contact with the plunger rod, making it difficult to remove the plunger rod.
[0004]
In order to solve such a problem, a projection is formed at the tip (screw tip) of the gasket engaging portion of the plunger rod, and the gasket made of elastic material is distorted to reduce the repulsive force. A technique of improving the separability by using the same has already been disclosed (JP-A-9-308689). However, in this method, since the shape of the projection at the tip of the plunger rod screw and the shape of the bottom of the female screw hole of the gasket do not match, the area around the liquid contact of the gasket is also distorted at the time of screwing, and the airtightness of the syringe and the syringe There was a possibility that the position holding property of the gasket in the inside was deteriorated. There is also disclosed a plunger rod in which a male screw portion having a non-circular thread outer peripheral shape is formed at a front portion thereof, which is detachably screwed with a female screw portion of a gasket (Japanese Patent Application Laid-Open No. H11-114062). Gazette). According to the present invention, if a bar-shaped protruding end is formed at the tip of the male screw portion, the thread flat portion of the male screw portion is prevented from closely contacting the inner bottom wall of the female screw portion of the gasket. This is a technique that allows the jar rod to be more easily removed. However, radiopharmaceuticals are generally discarded several days after the amount of radioactivity is sufficiently attenuated, so that the separation of the gasket and the plunger rod is not sufficiently satisfactory for practical use. Improvement to one that is easy to separate has been strongly desired.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the circumstances as described above, in a syringe pre-filled with general pharmaceuticals or radiopharmaceuticals, when separately discarding the plunger rod for the purpose of reducing waste after administration, Provided is a plunger rod for an injection syringe that can be very easily separated from a gasket even after several days from the administration of a drug solution.
[0006]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a joining surface between a plunger rod and a gasket is coated with a resin having low frictional resistance. With such a configuration, the frictional resistance of the joint surface between the gasket and the plunger rod is reduced, so that in the separating operation, the gasket does not rotate with the rotation of the plunger lot, and the separation can be performed extremely easily and reliably. it can.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a cross section of the distal end of a plunger rod for an injection syringe of the present invention used for a syringe filled with a drug solution, and FIG. 2 shows a schematic perspective view of the plunger rod. Hereinafter, description will be made with reference to FIG. Reference numeral 10 denotes a plunger rod having a male threaded portion 12 which is screwed to a gasket 14 at a tip portion 21 thereof. At the time of separation of the plunger rod 10 after administration of the chemical solution, at least a part of the male screw portion 12 or the front end face 11 where the plunger rod 10 and the gasket 14 are in contact with each other is made of fluorine or the like in order to reduce the frictional force with the gasket 14. It is covered with a resin with good slidability. Further, the female screw portion 15 in contact with the male screw portion 12 may be coated with the resin, and at least one of the front end surface 11 and the male screw portion 12 is formed of a resin having good slidability such as fluorine. May be. The plunger rod of the product of the present invention is made of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, Chlorotrifluoroethylene, chlorotrifluoroethylene-ethylene copolymer, polyvinylidene fluoride, polyvinyl fluoride, or various vinyl ethers having a functional group such as a fluoroolefin and an alkyl group, a cycloalkyl group, a hydroxylalkyl group or a carboxyl group. After applying a fluororesin such as a copolymer bonded alternately, the resin is baked and dried by a conventional method. As the resin that can be used in the present invention, in addition to the above-mentioned fluorine-based resin, those selected from silicon-based resin, polyethylene-based resin, and polypropylene-based resin are also preferable in terms of chemical resistance, and among them, polyfluorinated resin, which is a fluorine-based resin, is preferred. Ethylene is most preferred. The resin may contain a metal, for example, nickel-polyethylene fluoride or the like. FIG. 2 shows an example of a plunger rod for an injection syringe according to the present invention which is particularly suitable for use in a syringe filled with a radiopharmaceutical. Radiation in which the tip 21 of the plunger rod 10 is coated with a fluororesin is shown. It is composed of a shielding material.
[0008]
Embodiments of the present invention will be described below.
Manufacture plunger rod with fluororesin processing (polyethylene processing) at the tip (tungsten part including male screw part) of plunger rod with radiation shielding material used for syringe filled with radiopharmaceutical liquid Then, after mounting on the gasket in the syringe, the separability between the gasket and the plunger rod with the passage of days was compared. The following plunger rods are screwed and attached to the gasket in the syringe filled with the drug solution with the force required for normal operation by hand. Next, after being left standing at room temperature for 30 days, a test was performed to determine whether the gasket could be removed from the plunger rod by a manual operation with normal force without idling. The results are as shown in Table 1.
[0009]
The present invention: a plunger rod shown in FIG. 2 having a fluororesin at the tip (a tungsten portion including a male screw portion) of a plunger rod provided with a radiation shielding material (the male screw portion has a substantially triangular prism shape).
Conventional product 1: Plastic plunger rod shown in FIG. 4 that does not have a fluororesin at the tip (male thread) Conventional product 2: At the tip (tungsten portion including male thread) of plunger rod with radiation shielding material Plunger rod shown in Fig. 3 without fluorine resin (male thread part is cylindrical)
Conventional product 3: Plunger rod shown in FIG. 2 (the male screw portion has a substantially triangular prism shape) without a fluororesin at the tip (tungsten portion including a male screw portion) of the plunger rod with radiation shielding material
[0010]
[Table 1]
Plunger rod removal test

[0011]
【The invention's effect】
As described above, since the plunger rod of the present invention used for the medical syringe has the joint surface with the gasket coated with the resin having a small frictional resistance, the close contact between the two is prevented, and the separability is maintained. . This makes it possible to very easily and reliably remove the plunger rod and separate and discard it even in a syringe that has been left for several days after administration, which is usually difficult to remove.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view in the axial direction of a main part showing a screwed state of a plunger rod and a gasket of the present invention.
FIG. 2 is a schematic perspective explanatory view showing an example of a conventional and inventive tungsten plunger rod (the male screw portion has a substantially triangular prism shape).
Conventional product: The tip portion 21 including the male screw portion 12 is not covered with a fluororesin.
The present invention: The front portion 21 including the male screw portion 12 is coated with a fluororesin.
FIG. 3 is a schematic perspective explanatory view showing an example of a conventional tungsten plunger rod (the male screw portion has a columnar shape).
Conventional product: The tip portion 21 including the male screw portion 12 is not covered with a fluororesin.
The present invention: The front portion 21 including the male screw portion 12 is coated with a fluororesin.
FIG. 4 is a schematic perspective explanatory view showing an example of a conventional plastic plunger rod.
[Explanation of symbols]
10; plunger rod 11; tip end face 12; male thread 13; syringe 14; gasket 15; female thread 20; radiation shielding tip 21;

Claims (3)

In a medical syringe comprising a cylinder, a gasket, and a plunger rod, at least a part of a joint surface between the gasket and the plunger rod has a resin selected from a fluororesin, a silicone resin, a polyethylene resin, or a polypropylene resin. A plunger rod. The plunger rod according to claim 1, wherein the fluororesin is a resin containing polyfluorinated ethylene or metal-containing polyfluoroethylene. The plunger rod according to claim 1, wherein the plunger rod is used for a syringe filled with a radioactive drug solution.

Images