JP2003088586A - Prefilled syringe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact prefilled syringe with short total length capable of preferably preventing the reuse and never causing the backflow of a content solution after inserting a plunger. SOLUTION: This prefilled syringe 10 comprises a cylinder 11 having an open end 14 at one end part and a discharge port 15 or the like at the other end part; the plunger 12 inserted into the cylinder 11 from the open end 14 side; and a gasket 13 provided at the tip of the plunger 12 to closely slide in the cylinder 11. The length L from the one end to the other end of the cylinder 11 is 3 times or less the outer diameter D thereof. The plunger 12 is preferably perfectly housed in the cylinder 11 after insertion, and more preferably locked within the cylinder 12 when the gasket 13 is allowed to abut on the discharge port 15-side end part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prefilled syringe which is compact and has excellent storability and handleability.

[0002]

2. Description of the Related Art Generally, a drug solution used for drip or the like is marketed in a flexible infusion container, an infusion bottle or the like. On the other hand, drug solutions such as vitamins and antibiotics are supplied in a state that they are filled in a syringe because the amount administered per infusion is extremely small, about several mL. It is used after being mixed with the containing liquid such as.

As a syringe (prefilled syringe) pre-filled with such a drug solution, for example, as shown in FIGS. 7 and 8, a cylinder (outer cylinder) 81 elongated in the axial direction x is charged with the drug solution, and the distal end is filled with the drug solution. It is known that a plunger (inner cylinder) 82 having a gasket 83 is inserted into a cylinder 81. However, the prefilled syringe 80 cannot be stored in a state where the plunger 82 is pushed into the cylinder 81 because the cylinder 81 is preliminarily filled with the chemical liquid. Moreover, the plunger 82 is usually a member longer than the entire length of the cylinder 81. Therefore, it is unavoidable that the total length of the prefilled syringe 80 becomes extremely long, and there is a problem in that it is inconvenient when it is bulky and stored or stored. Note that FIG.
Reference numeral 86 indicates a finger collar, and reference numeral 87 indicates a thumb pad.

Further, in recent years, in the medical field, the reuse of syringes and injection needles has been severely restricted particularly for the purpose of preventing infectious diseases. However, conventional prefilled syringes as shown in FIG. 7 and FIG. In 80, since the plunger 82 can be freely inserted and removed from the used cylinder 81, there is a possibility that the syringe once used may be reused. Further, in the conventional prefilled syringe 80, the gasket 83 provided at the tip of the plunger 82 is usually made of an elastic material such as rubber, and when the plunger 82 is pushed in, the tip of the cylinder 81 (on the discharge port 85 side). When it is pressed against the inner wall of the plunger 82, the elasticity of the gasket 83 itself may cause the plunger 82 to return. When the plunger 82 returns in this way, the discharge port 85 is pushed by pushing the plunger 82.
There is a possibility that the solution or the like in the prefilled syringe 80 discharged from the backflow back into the syringe 80.

Therefore, a main object of the present invention is to provide a prefilled syringe which has a short overall length and is compact, and preferably has a good handleability (operability). Another object of the present invention is to provide a prefilled syringe in which it is difficult to withdraw the plunger and reuse the syringe after the plunger has been pushed in and the content liquid has been discharged. Still another object of the present invention is to provide a prefilled syringe in which the content liquid or the like does not flow back after the content liquid is discharged by pushing the plunger.

[0006]

Means for Solving the Problems and Effects of the Invention A prefilled syringe according to the present invention for solving the above problems has an open end at one end and a discharge port or a needle insertion hole at the other end. A cylinder, a plunger inserted into the cylinder from the open end side, and a gasket at the tip of the plunger that seals the cylinder and slides in the cylinder are provided. One end of the cylinder The length from the part to the other end is less than or equal to 3 times the outer diameter of the cylinder.

According to the present invention, the total length of the prefilled syringe can be shortened to make it compact, and even if the prefilled syringe is in a state in which the cylinder is filled with the drug solution before use, the prefilled syringe can be made into a compact body. It is not bulky and can reduce or eliminate inconveniences during storage and storage.

In the prefilled syringe of the present invention, it is preferable that the cylinder has a finger collar on an outer peripheral surface of a substantially middle portion in the axial direction of the cylinder. Since the prefilled syringe of the present invention has a short total length of the cylinder, when a flange for holding a finger is provided at the open end of the cylinder like the conventional prefilled syringe, the handleability and operability when pushing the plunger are deteriorated. May occur. On the other hand, in the case where the finger collar is provided at a substantially middle portion in the axial direction of the cylinder, the plunger is completely housed in the cylinder even though the total length of the cylinder is short. Despite this, the handling and operability are not impaired when the liquid medicine is discharged.

In the prefilled syringe of the present invention, the cylinder is partitioned into a plurality of chambers in the circumferential direction by a partition wall continuous from the open end side to the tip of the discharge port or the needle insertion hole. Is preferred. As a prefilled syringe that separately stores two types of chemicals, for example, one shown in FIG. 9 is known (see Japanese Patent Laid-Open No. 8-224305). In this prefilled syringe 90, the inside of the cylinder 91 is separated into two chambers 91a and 91b by a stopper 93a, and when the stopper 93a is moved in the axial direction x in conjunction with the pushing of the plunger 92 (and the gasket 93). In addition, the chemical solutions contained in the chambers 91a and 91b are mixed in the bypass 94 portion where the inner diameter of the syringe 91 is partially thick. Note that FIG.
Reference numeral 95 denotes a discharge port, reference numeral 96 denotes a finger collar, and reference numeral 97 denotes a thumb pad.

However, in the prefilled syringe 90, the chambers 91a and 91b for separately containing the two kinds of chemicals are contained.
Are arranged vertically in the cylinder 91 (prefilled syringe 9
Since the cylinder 91 and the plunger 92 are combined, the total length of the prefilled syringe becomes extremely long. Therefore, the syringe becomes bulky, and the problem of inconvenience in storage, storage, etc. becomes remarkable.

On the other hand, the above-mentioned prefilled syringe in which the inside of the cylinder is partitioned into a plurality of chambers in the circumferential direction (hereinafter referred to as "multi-chamber separation type prefilled syringe").
Say. According to (1), two or more drug solutions can be accommodated in one syringe in a separated state, and more than two chambers are arranged in parallel (in the circumferential direction of the syringe in the circumferential direction of the syringe, not in a column as in the above publication). Being arranged side by side, the syringe can be prevented from becoming too long and it will not be bulky. Therefore, the problem of inconvenience during storage and storage can be alleviated.

In the prefilled syringe of the present invention, it is preferable that the plunger is completely accommodated in the cylinder when the plunger is pushed into the cylinder. In this case, the length of the plunger is short enough to be completely accommodated in the cylinder in a state where the plunger is pushed in, so that the prefilled syringe can be made more compact. Moreover, since the plunger is completely housed in the syringe, it becomes difficult to pull out the plunger from the cylinder after using the prefilled syringe. Therefore, reuse of the syringe can be prevented.

When the plunger is completely housed in the cylinder, if the finger flange is provided at the open end of the cylinder, the handleability and operability at the time of pushing the plunger may deteriorate. is there. However, as in the case described above, by providing a finger collar at a substantially middle portion in the axial direction of the cylinder, even when the plunger is completely housed in the cylinder, the handleability at the time of pushing in the plunger is improved. -The operability is not impaired. This also applies to the multi-chamber separation type prefilled syringe described above.

In the prefilled syringe of the present invention, when the plunger is pushed into the cylinder to bring the gasket into contact with the end portion on the discharge port or needle insertion hole side, the plunger is locked in the cylinder. It is more preferable that the In this case, the gasket provided at the tip of the plunger is elastically repulsed, so that it is possible to prevent the plunger from trying to return after being completely pushed into the cylinder. Therefore, it is possible to prevent the backflow of the content liquid or the like.

Further, since it becomes more difficult to pull out the plunger from the cylinder after using the prefilled syringe, the reuse of the syringe can be prevented more reliably.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a prefilled syringe according to the present invention will be described in detail with reference to the drawings.
The prefilled syringe according to the present invention includes, for example, FIGS.
There are roughly two types of embodiments, one according to the embodiment shown in FIG. 4 (single-chamber prefilled syringe) and one according to the embodiment shown in FIGS. 5 and 6 (multi-chamber separated prefilled syringe). Can be mentioned.

Therefore, the two embodiments will be individually described below. [Single-chamber Prefilled Syringe] In the prefilled syringe (single-chamber type) according to the present invention, as shown in, for example, FIGS. 1 and 2, one end is an open end 14 and the other end is a discharge port 15 ( Or a cylinder 11 having a needle insertion hole)
And the plunger 12 inserted into the cylinder 11 from the open end 14 side, and the cylinder 1 at the tip of the plunger 12.
Gasket 1 for sealing 1 and sliding in cylinder 11
3 and the length from one end of the cylinder 11 to the other end is 3 times the outer diameter of the cylinder 11.
It is characterized by being less than twice.

(Cylinder) Regarding the cylinder (outer cylinder) 11 of the prefilled syringe 10, the length L from one end to the other end thereof is not more than 3 times the outer diameter D of the cylinder 11. Is required (see Fig. 2 (d)). By adjusting the length L to be not more than 3 times the outer diameter D, the total length of the prefilled syringe 10 can be shortened and made compact. Therefore, even when the cylinder 11 is filled with the drug solution before use, the cylinder 11 does not become bulky as in the conventional prefilled syringe, and the inconvenience during storage and storage can be reduced or eliminated.

The ratio of the length L to the outer diameter D is not particularly limited as long as it satisfies the above range, and within the above range, the prefilled syringe 1
It may be appropriately set according to the amount of the drug solution stored in 0, the operability of the prefilled syringe 10, and the like. The ratio of the length L to the outer diameter D is not limited to this,
Considering the operability of the prefilled syringe and the amount of the contained drug solution, it is preferable that the length L is 0.5 to 2.5 times the outer diameter D, particularly in the range.
For example, when the amount of the prefilled syringe containing the liquid medicine is about 5 mL, the length L can be adjusted to about 2.5 cm and the outer diameter D can be adjusted to about 2.0 cm. By adjusting in this way, it is possible to make the syringe compact while maintaining good operability and securing a sufficient space for holding the liquid medicine in the cylinder and holding the gasket and the plunger.

FIG. 3 and FIG. 4 are vertical cross-sectional views showing a modified design example of the single-chamber type prefilled syringe according to the present invention. In both the prefilled syringe 10 'shown in FIG. 3 and the prefilled syringe 10''shown in FIG. 4, when the plunger 12' is pushed into the cylinder 11 ', 11'', the plunger 12' Designed to be completely contained within 11 ''.

By being designed in this way,
Cylinder 1 after using prefilled syringe 10 '
Since it becomes difficult to pull out the plungers 12 ′ and 12 ″ from the 1 ′ and 11 ″, it is possible to prevent reuse of the syringes 10 ′ and 10 ″. Further, in this case, since the plungers 12 ′, 12 ″ are also short enough to be completely accommodated in the cylinders 11 ′, 11 ″, the prefilled syringes 10 ′, 10 ′ even before use. '
Is even shorter and more compact.

Further, in the modified design shown in FIGS. 3 and 4, a locking ridge 18 is provided on the inner peripheral surface near the open end 14 of the cylinders 11 ', 11'',
When the plunger 12 'is pushed all the way in, the outer peripheral surface of the thumb pad 17' and the locking projection 18 are engaged. Since the gasket 13 provided at the tip of the plunger 12 'is usually made of an elastic material such as rubber as described above, the cylinders 11', 11 ''
When this is pressed against the inner wall of the tip of the (the discharge port 15 side),
The elasticity of the gasket 13 itself may cause the plunger 12 'to return.

When the plunger 12 'moves back, the liquid content in the syringe may flow back at the discharge port 15. Therefore, such a situation should be avoided. However, in the modified design shown in FIGS. Since the thumb pad 17 'of the'and the outer peripheral surfaces of the cylinders 11' and 11 '' are engaged and the plunger 12 'is locked in the cylinders 11' and 11 '', the plunger 12 'and the gasket 13 Backflow is prevented, and therefore, the situation in which the liquid content of the syringe or the like flows backward can be avoided.

The locking projection 18 is not particularly limited as long as it engages with the thumb pad 17 'of the plunger 12'. Thus, for example, cylinders 11 ', 1
It does not need to be a continuous ridge along the inner peripheral surface of 1 ″, and may be a protrusion provided at several places on the inner peripheral surface. The inner circumference of the open end 14 of the cylinder 11 ″ may be appropriately designed according to the outer diameter of the thumb pad 17 ′, as shown in FIG. 4, for example. When using a prefilled syringe, that is, when pushing the plunger into the cylinder, it is usually necessary to put your finger on the finger collar provided at the open end of the cylinder and press the thumb pad at the tip of the plunger. Done. Here, in all of the prefilled syringes (10, 10 ′, 10 ″) shown in FIGS. 1 to 4, the finger collar 16 has the open end 14 of the cylinder (11, 11 ′, 11 ″).
Not in the axial direction x, but in a substantially intermediate portion in the axial direction x.

The prefilled syringes (10, 10 ', 10'') shown in FIGS. 1 to 4 are all cylinders (11, 1).
1 ', 11'') has a short overall length, and in particular in the syringe shown in FIGS. 3 and 4, the plunger (12', 12 '') is completely housed in the cylinder (11 ', 11''). Is designed to. In such a case, if the finger collar 16 is provided at the open end 14 of the cylinder (11, 11 ', 11''), the operability of the syringe may be significantly reduced.
The prefilled syringe (10, 10 ', 1 shown in FIGS.
In 0 "), the finger collar 16 is a cylinder (11, 11 ', 11")
The plunger (1
(2,12 ', 12'') is short, and even if it is completely accommodated in the cylinder, its handling and operability will not be impaired.

The material used for forming the cylinder 11 is not particularly limited, but it is medically acceptable, for example, glass; polypropylene, polyethylene, cyclic polyolefin, polyvinyl alcohol, polystyrene, various elastomers and the like. Synthetic resin; metals such as stainless steel and aluminum. Cylinder 1
0 is preferably transparent so that the contained chemical solution can be visually observed.

Further, when the contained chemical liquid is liable to be deteriorated by gas such as oxygen or moisture, it is preferable to form the cylinder 10 by using a material having excellent barrier properties. Examples of the material having the gas barrier property and the water barrier property include glass, metals such as stainless steel and aluminum among the materials exemplified above. Among the synthetic resins, cyclic polyolefin, polyvinyl alcohol and the like are suitable as the material having gas barrier property and moisture barrier property. Further, the synthetic resin of the above-mentioned examples, which is vapor-deposited with silicon oxide or aluminum oxide, the resin having the above-mentioned barrier property is laminated, or a laminate thereof is also suitable as the material having the gas barrier property or the moisture barrier property. . When the contained chemical solution is easily decomposed by light, a light shielding film may be laminated.

(Plunger) In the prefilled syringe (10, 10 ', 10'') according to the present invention, the plunger 1
The total length of 2, 12 ′ is not particularly limited, but in order to make the syringe shorter and more compact, the total length of the plungers 12, 12 ′ should be such that it is completely housed in the cylinder. It is preferable to shorten it. The shape and size of the thumb pads 17, 17 'provided at the tips of the plungers 12, 12' (tips on the side opposite to the gasket 13) are not particularly limited, but as described above, , 12 'to the cylinder (11, 11',
11 ''), but with the cylinder (11,
To achieve the purpose of locking with 11 ', 11''), place the thumb pad 17, 17' in the cylinder (11, 11 ', 1
It is preferable to make it a circle slightly smaller than the inner diameter of 1 '').

The plunger 12, 12 'and the cylinder (11,
11 ', 11'') is not limited to the engagement with the configurations shown in FIGS.
Various forms can be adopted as long as 2'can be fixed in the cylinder (11, 11 ', 11'') to the extent that it does not return due to the repulsive force of the gasket 13.
In addition, the plunger 12, 12 'and the cylinder (11, 11',
11 ") is limited to the engagement between the thumb pad 17, 17 'and the ridges / protrusions provided on the inner peripheral surface of the cylinder (11, 11', 11"). If the plungers 12 and 12 'can be fixed in the cylinders (11, 11' and 11 '') to the extent that they do not return due to the repulsive force of the gasket 13, various forms of engagement are possible. The form of can be adopted.

The material used to form the plungers 12 and 12 'is not particularly limited, but the material is not limited to the plungers 12 and 12' via the thumb pads 17 and 17 'during the discharge operation of the chemical liquid. Since a load is applied, it is required to use one that can withstand such a load. Examples of materials suitable for such applications include various hard materials such as glass; metals such as stainless steel and aluminum; hard synthetic resins such as polypropylene and polystyrene.

(Gasket) As the material used to form the gasket 13, natural rubber, synthetic rubber, various elastomers, etc. can be mentioned, as in the case of the gaskets in conventionally known syringes and prefilled syringes. The shape of the gasket 13 is not particularly limited and may be designed in the same manner as a conventionally known syringe or the like.

(Discharge port or needle insertion hole) Cylinder (1
1, 11 ', 11'') is provided with a hole (not shown) for inserting a discharge port 15 or a needle such as an injection needle.
The shape of the discharge port or the needle insertion hole is not particularly limited, and may be appropriately designed according to the application of the prefilled syringe and the like as in the conventionally known syringe and the like.
When a discharge port is provided at the tip of a cylinder (11, 11 ', 11''), the shape of the discharge port is the same as that of a normal syringe, etc. Etc. can be adopted. It is usually preferable to seal the discharge port or the needle insertion hole. As the sealing member, an elastic cap, a luer lock type cap, a release film, or the like may be adopted depending on the application of the discharge port or the needle insertion hole, the syringe, or the like.

(Containing Chemical Solution) The chemical solution contained in the prefilled syringe of the present invention is not particularly limited, and various conventionally known chemical solutions can be mentioned. Among them, it is suitable for the purpose of accommodating vitamins, trace elements, heparin, antibiotics, anticancer agents, etc. which are usually supplied in the form of prefilled syringes.

[Multi-chamber Separation-Type Prefilled Syringe] The prefilled syringe (multi-chamber separation type) according to the present invention has, for example, as shown in FIG. 5, one end portion having an open end 34 and the other end portion having a discharge port. A cylinder 31 having 35 (or a needle insertion hole), a plunger 32 inserted into the cylinder 31 from the open end 34 side, and a gasket 33 at the tip of the plunger 32 for sealing the cylinder 31 and sliding in the cylinder 31. And the length from one end of the cylinder 31 to the other end is not more than 3 times the outer diameter of the cylinder 31, and the cylinder 31 discharges from the open end 34 side. A plurality of chambers (31a, 31a, 31a)
It is divided into b).

FIG. 6 is a sectional view of the multi-rate separation type prefilled syringe 30 shown in FIG. 5 (a). 6 (a)-
5C is a sectional view taken along the line AA, a sectional view taken along the line BB, and a sectional view taken along the line CC of FIG. According to the multi-chamber separation type prefilled syringe 30, as shown in FIGS. 6 (a) to 6 (c),
Since the chambers 31a and 31b for containing the liquid medicine are separated by the partition wall 39 up to the tip of the discharge port 35, there is no risk of mixing the liquid medicine when storing the liquid medicine in the prefilled syringe 30. Each room (31a, 31b)
The liquid medicine stored in the cylinder 31 pushes the plunger 32 into the cylinder 31 (see FIG. 5 (b)), and the discharge port 3 of the cylinder 31 is discharged.
When discharged from 5, they are mixed with each other.

In the multi-chamber separation type prefilled syringe 30 shown in FIG. 5, the length L'from one end of the cylinder 31 to the other end thereof is shown in FIG.
The outer diameter D'of 1 is designed to be 3 times or less. The preferred range of the ratio of the length L ′ and the outer diameter D ′ and the effect of setting the ratio of the length L ′ and the outer diameter D ′ in the above range are the single-chamber prefilled syringes described above. It is similar to the case of.

The syringe 31 of the multi-chamber separation type prefilled syringe 30 shown in FIG. 5 is designed to be completely accommodated when the plunger 32 is pushed in, as shown in FIG. On the inner peripheral surface on the side of the open end 34, a locking projection 38 for engaging the thumb pad 37 of the plunger 32 is provided. The effect of the syringe 31 having a length capable of completely accommodating the plunger 32 and the effect of the plunger 32 being engaged by the locking projection 38 and locked in the syringe 31 are as described above. This is similar to the case of the single-chamber type prefilled syringe.

In the syringe 31 of the multi-chamber separation type prefilled syringe 30 shown in FIG. 5, the finger collar 36 is
It is provided on the outer peripheral surface of the cylinder 31 at a substantially intermediate portion in the axial direction x. The effect of providing the finger collar 36 at the substantially intermediate portion in the axial direction x of the cylinder 31 is the same as that of the above-described single-chamber type prefilled syringe. In the multi-chamber separation type prefilled syringe 30, the material used to form the cylinder 31, the plunger 32, and the gasket 33, the shape of the ejection port 35 (needle insertion hole), the ejection port 35 and the needle insertion hole are sealed. As the sealing member for this, the same one as in the case of the above-mentioned single-chamber type prefilled syringe can be mentioned.

The chemical liquid to be stored in the storage chambers 31a and 31b of the cylinder 31 of the multi-chamber separation type prefilled syringe 30 is not particularly limited, and the same one as in the case of the above-mentioned single chamber type prefilled syringe is used. Can be mentioned. The multi-chamber separation type prefilled syringe 30
Is a combination of drugs that are usually administered simultaneously,
It is suitable for accommodating those which cause problems such as alteration when stored in a mixed state.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a prefilled syringe according to the present invention.

2 (a) is a front view of the prefilled syringe 10 shown in FIG. 1, (b) is a right side view thereof, (c) is a front view showing a state in which a plunger 12 is pushed into a cylinder 11, (d). FIG. 4 is a front view showing a state in which the cylinder 11 and the plunger 12 are separated.

FIG. 3 is a vertical cross-sectional view showing an example of design change of a single-chamber type prefilled syringe, showing a state where a plunger 12 ′ is pushed into a cylinder 11 ′.

FIG. 4 is a vertical cross-sectional view showing another example of design change of the single-chamber type prefilled syringe, showing a state in which the plunger 12 ″ is pushed into the cylinder 11 ″.

5A and 5B are vertical cross-sectional views showing an embodiment of a multi-chamber separation type prefilled syringe according to the present invention, in which FIG. 5A is a state before pushing the plunger 32 into the cylinder 31, and FIG. The state after pushing into the cylinder 31 is shown.

6A is a cross-sectional view taken along the line AA in FIG. 5A, and FIG.
5A is a sectional view taken along line BB in FIG. 5A, and FIG. 5C is a sectional view taken along line CC in FIG. 5A.

FIG. 7 is a perspective view showing an example of a conventional prefilled syringe.

8 is a front view of the prefilled syringe 80 shown in FIG. 7, (a) showing a state before use, and (b) showing a state in which a plunger 82 is pushed into a cylinder 81.

FIG. 9 is a vertical sectional view showing an example of a conventional two-chamber separation type prefilled cylinder.

[Explanation of symbols]

10 prefilled syringes, 11 cylinders, 1
2 plungers, 13 gaskets, 14 open ends, 15 discharge ports, 16 finger collars, 18 locking ridges, 30 prefilled syringes (multi-chamber separation type),
31 cylinders, 31a chamber, 31b chamber, 3
2 Plungers, 33 gaskets, 34 open ends,
35 discharge ports, 38 locking projections, 39 bulkheads,
D outer diameter, L length, x cylinder axial direction, y
Circumferential direction of cylinder.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fujio Inoue             41, 240 Odai, Otsu Town, Naruto City, Tokushima Prefecture F-term (reference) 4C066 AA07 CC01 DD12 EE14 FF05                       GG01 GG11 GG15

Claims (5)

[Claims] 1. A cylinder having an open end at one end and a discharge port or a needle insertion hole at the other end, a plunger inserted into the cylinder from the open end side, and a tip of the plunger. And a gasket that seals the cylinder and slides in the cylinder, and the length from one end of the cylinder to the other end is 3 times or less of the outer diameter of the cylinder. A prefilled syringe characterized in that. 2. The prefilled syringe according to claim 1, wherein the cylinder is provided with a collar for a finger on an outer peripheral surface at a substantially intermediate portion in the axial direction of the cylinder. 3. The cylinder is partitioned into a plurality of chambers in the circumferential direction by a partition wall continuous from the open end side to the tip of the discharge port or the needle insertion hole. Alternatively, the prefilled syringe described in 2. 4. The prefilled syringe according to claim 1, wherein the plunger is completely housed in the cylinder when pushed into the cylinder. 5. The plunger is locked in the cylinder when the plunger is pushed into the cylinder to bring the gasket into contact with the end portion on the discharge port or needle insertion hole side. The prefilled syringe according to claim 4.