JP2002017855A - Plunger for syringe of radioactive drug medicine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plunger which has a male screw part to be screwed attachably and detachably to/from the gasket of a syringe filled with radioactive drug medicine, whose male screw is sufficiently strong lest it is broken or comes off from a tip part when dropping the plunger by mistake and which is simply produced since the number of parts is reduced. SOLUTION: The male screw part 52 and the tip part 54 are integrally formed of radioactive shielding material obtained by filling plastic with tungsten powder and grass filler. A knob part 56 is formed of the same radioactive shielding material. A rod part 58 is made of plastic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plunger for a syringe filled with a radiopharmaceutical, and more particularly to a plunger using a radiation shielding material as a part of the material.

[0002]

2. Description of the Related Art A radiopharmaceutical container is composed of a direct container for directly storing a radiopharmaceutical and an indirect container for storing the direct container. The direct container is a syringe filled with a drug solution in which a radiopharmaceutical is previously filled. (Prefilled syringe) is commonly used. When administering radiopharmaceuticals, in order to reduce the exposure of the user and the recipient, a lead glass viewing window should be placed on a cylinder made of a high-density substance with a radiation shielding effect, such as lead or a tungsten alloy. Usually, the prefilled syringe is housed in the provided cylindrical radiation shielding member. The radiation shield is commonly referred to as a dosing shield. In recent years, sales are often performed in a state in which a prefilled syringe placed in an administration shield is housed in an indirect container made of lead or a tungsten alloy.

FIG. 2 is a sectional view of the prefilled syringe described above. The prefilled syringe 2 includes a syringe 6 made of transparent glass filled with a radiopharmaceutical (injection solution) 4 therein, and a rubber stopper 8 inserted into the tip of the syringe 6.
And a rubber gasket 10 inserted into the rear end of the syringe 6. The injection solution 4 is filled between the rubber stopper 8 and the gasket 10. On the upper surface of the gasket 10,
Plunger mounting hole 1 into which tip of plunger is screwed
2 are formed. The above-mentioned radiopharmaceutical container is provided with a separately packaged plunger and injection needle. The plunger 20 is integrally formed of plastic,
Male screw part 24 at the lower end of rod part 22 and knob part 2 at the upper end
6 are provided. The injection needle is attached to the tip of the syringe 6.

However, when a radiopharmaceutical is administered by attaching a plunger integrally formed of plastic to the gasket of the prefilled syringe contained in the administration shield, the radiopharmaceutical is pushed out, that is, from the plunger side opening of the syringe. Radiation exposure could not be prevented.

[0005] Japanese Patent Application Laid-Open No. H11-164886 proposes a plunger used for a prefilled syringe filled with a radiopharmaceutical. As shown in FIG. 3, the plunger 30 has a male thread 32 connected to a gasket of a prefilled syringe, a tip 34 following the male thread 32, and a knob 3 with which a finger contacts.
6, a rod part 3 for connecting the tip part 34 and the knob part 36
8, the tip portion 34 and the knob portion 36 are formed of a radiation shielding material formed of a composite material obtained by mixing tungsten powder with a plastic resin, and the male screw portion 32 and the rod portion 38 are formed of a plastic resin. It was done. JP-A-11-164886
The plunger of No. 3 can reduce the radiation exposure from the plunger side opening of the syringe by forming the distal end portion 34 with a radiation shielding material. In the figure, reference numeral 40 denotes a claw-shaped projection provided at the tip of the male screw portion 32. The projection 40 is provided to prevent the external thread 32 from biting into the gasket.

[0006]

However, the plunger for a radiopharmaceutical syringe disclosed in Japanese Patent Application Laid-Open No. H11-164886 has the following disadvantages. (1) Since the male screw portion 32 is made of a plastic resin, the strength of the male screw portion 32 is insufficient, and the male screw portion 32 may be damaged when the plunger is accidentally dropped. (2) Since the portion between the external thread portion 32 and the tip portion 34 is a joint between the radiation shielding material and the plastic resin, which are different materials, the joining strength of this joint is not sufficient and the plunger is accidentally dropped. When the male screw part 3 is removed, the male screw part 32 may come off from the distal end part 34.
The strength of No. 2 was insufficient. (3) Since four male threads 32, a tip 34, a knob 36, and a rod 38 are required as components, the number of components is large and the manufacture of the plunger is complicated.

The present invention has been made in view of the above-mentioned circumstances, and the male screw portion has a sufficient strength, and when the plunger is accidentally dropped, the male screw portion is damaged, or the male screw portion is moved from the tip end. It is an object of the present invention to provide a plunger for a radiopharmaceutical syringe which does not come off and has a small number of parts and is easy to manufacture.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a male thread, a tip following the male thread, a knob, and a rod provided between the tip and the knob. A male screw part is detachably screwed into a gasket of a syringe filled with a radiopharmaceutical, wherein the male screw part and the tip part are made of plastic mixed with tungsten powder and glass filler. Provided is a plunger for a radiopharmaceutical syringe, which is integrally formed of a material.

A radiation shielding material obtained by blending the above-mentioned plastic with a tungsten powder and a glass filler is as follows:
Higher strength than plastics and radiation shielding materials obtained by blending tungsten powder with plastics. In the plunger of the present invention, since the male screw portion and the tip portion are integrally formed from a high-strength radiation shielding material obtained by mixing tungsten powder and glass filler with plastic, the male screw portion has sufficient strength, and the plunger is erroneously formed. The male screw portion is not damaged when dropped, and the male screw portion does not come off from the tip. Further, since the male screw portion and the tip portion are formed integrally, the number of parts can be reduced as compared with the case where these are formed separately.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples. FIG. 1 is a sectional view showing an embodiment of the plunger of the present invention. The plunger 50 of the present example includes a male screw part 52 detachably screwed into a plunger mounting hole of a gasket of a prefilled syringe, a tip part 54 following the male screw part 52, a disk-shaped knob part 56 with which a finger contacts,
A rod portion 58 provided between the distal end portion 54 and the knob portion 56; and a claw-shaped projection 6 provided at the distal end of the male screw portion 52.
It consists of 0. The projection 60 is provided to prevent the external thread 32 from biting into the gasket.

In the plunger of this embodiment, the male screw 5
2. The tip 54 and the projection 60 are integrally formed of a radiation shielding material obtained by filling a tungsten powder and a glass filler in plastic. The knob 56 is formed of the same radiation shielding material. In addition, rod part 5
Reference numeral 8 is formed of plastic. The plunger of this example is attached to a gasket of a prefilled syringe filled with a radiopharmaceutical, and the distal end portion 54 is made of a radiation shielding material, so that radiation exposure from the plunger side opening of the syringe can be reduced. it can.
The reason why the knob 56 is formed of a radiation shielding material is to reduce radiation exposure from the plunger-side opening of the syringe more reliably and to improve the weight balance of the entire plunger. The plunger of this example is formed by a composite forming method such as an insert forming method.

In the present invention, for example, the following can be used as the plastic of the radiation shielding material, the tungsten powder and the glass filler, and the plastic forming the rod portion.

(Plastic of Radiation Shielding Material) The plastic used for the radiation shielding material may be either a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin, for example, polyamide, polyester, polycarbonate, polyether sulfide. Phone, polyolefin, polyphenylene oxide, polyphenylene sulfide,
Polyetheretherketone, AS resin, AN resin, A
BS resin and the like can be mentioned. Particularly preferred are polyamides, especially nylon 6, nylon 12.

(Tungsten Powder for Radiation Shielding Material) The specific gravity of the tungsten powder used for the radiation shielding material is preferably about 19, and the average particle diameter is preferably 50 μm or less.
In particular, a tungsten powder having a particle size of 10 μm or less and a particle distribution of 50% by weight or more based on the entire tungsten powder and a particle size of 20 μm or more having a particle distribution of 30% by weight or more is preferable. In the case of such a particle size distribution, the fluidity particularly at the time of melting is improved.

(Glass Filler of Radiation Shielding Material) Examples of the glass filler used for the radiation shielding material include glass fibers (long fibers and short fibers), glass powder, glass spheres and the like. Particularly preferred are glass fibers.

(Preferred Radiation Shielding Material) Preferred radiation shielding materials include, for example, those having the following compositions. (A) Plastic Type: Nylon 6 Compounding amount: 2 to 14% by weight (B) Tungsten powder Compounding amount: 77 to 97% by weight (C) Glass filler Type: Glass fiber Compounding amount: 1 to 15% by weight

The specific gravity of the radiation shielding material can be freely adjusted by changing the mixing ratio of the tungsten powder and the glass filler to be mixed, but the specific gravity of the radiation shielding material is 6-1.
5 is preferred.

(Plastic of rod part) As the plastic used for the rod part, any of a thermoplastic resin and a thermosetting resin can be used, but a thermoplastic resin is preferable, and for example, polyamide, polyester, polycarbonate, poly Ether sulfone, polyolefin, polyphenylene sulfide, polyphenylene sulfide, polyether ether ketone, AS resin, AN
Resin, ABS resin and the like can be mentioned.

[0019]

EXAMPLES The following three types of plungers (a) to (c) were produced, and their tip strength tests were performed to confirm the effects of the present invention.

(A) The plunger male screw part 52, tip part 54 and protrusion 60 of the present invention shown in FIG. 1 were integrally formed of a radiation shielding material (specific gravity 8) having the following composition. The knob 56 is formed of the same radiation shielding material. Rod part 5
8 was made of ABS resin. Radiation shielding material (A) Plastic Type: Nylon 6 Compounding amount: 7 to 8% by weight (B) Tungsten powder Compounding amount: 88 to 90% by weight (C) Glass filler Type: Glass fiber Compounding amount: 2 to 5% by weight

(B) In the plunger shown in FIG. 1, the radiation shielding material is not compounded with a glass filler. The male screw portion 52, the tip portion 54 and the projection 60 are integrally formed by a radiation shielding material (specific gravity 8) having the following composition. . The knob 56 is formed of the same radiation shielding material. Rod part 5
8 was made of ABS resin. Radiation shielding material (A) Plastic Type: Nylon 6 Compounding amount: 8.5% by weight (B) Tungsten powder Compounding amount: 91.5% by weight

(C) The conventional plunger tip 34 and knob 36 shown in FIG. 3 are each formed of a radiation shielding material (specific gravity 10) having the following composition. Male thread 32
The projections 40 are formed integrally with the ABS resin. The rod part 38 was formed of ABS resin. Radiation shielding material (A) Plastic Type: Nylon 6 Compounding amount: 5.7% by weight (B) Tungsten powder Compounding amount: 94.3% by weight

The deformation state of the projections after dropping each plunger on the stainless steel plate with the projections down, that is, a change in the height dimension (projection height before drop-projection height after drop). Measured with a digital microscope. The drop height of the plunger is 100mm, 200mm, 300
mm, 400 mm, and 500 mm. Table 1 shows the results.

[0024]

[Table 1]

From the results shown in Table 1, it was confirmed that the plunger of the present invention had good strength of the male thread portion. Further, the plunger of the present invention had good radiation shielding ability.

[0026]

As described above, the plunger for a radiopharmaceutical syringe according to the present invention has the following effects. The external thread and the tip are integrally formed of a high-strength radiation shielding material made of plastic mixed with tungsten powder and glass filler, so the external thread has sufficient strength, so if the plunger is accidentally dropped, etc. The external thread is not damaged and the external thread does not come off from the tip. Since the male screw part and the tip part are formed integrally, the number of parts can be reduced as compared with the case where these are formed separately. Not only the tip but also the external thread is made of a radiation shielding material, so if the specific gravity of the radiation shielding material is made equal to the conventional one, a higher radiation shielding ability than before can be obtained. Even if it is lower than before, the same radiation shielding ability as before can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a plunger for a radiopharmaceutical syringe according to the present invention.

FIG. 2 is a sectional view showing an example of a prefilled syringe.

FIG. 3 is a sectional view showing an example of a conventional plunger for a radiopharmaceutical syringe.

[Explanation of symbols]

 40 Plunger 42 Male thread part 44 Tip part 46 Knob part 48 Rod part 50 Projection

Claims (1)

[Claims] A male thread portion, a tip portion following the male thread portion,
A plunger comprising a knob portion and a rod portion provided between the distal end portion and the knob portion, wherein a male screw portion is detachably screwed into a gasket of a syringe filled with a radiopharmaceutical, the male screw portion and A plunger for a radiopharmaceutical syringe, wherein a tip portion is integrally formed of a radiation shielding material obtained by mixing a tungsten powder and a glass filler with plastic.