JP2016077355A - Prefilled syringe gasket and prefilled syringe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a prefilled syringe gasket in which a medical solution filled in a prefilled syringe is never leaked out.SOLUTION: A prefilled syringe gasket is a laminate gasket 13 and a coat 22 comprising at least one kind of silicon compound is applied on the surface of a sliding part 17. Both of the ratios before and after applying the coat 22 (Ry(after coating/before coating)) of respective maximum height Ry// and Ry⊥ in the circumferential direction of the sliding part 17 and in the vertical direction to the circumferential direction (slide direction) are 0.9 or less. Specifically, the coat 22 applied on the surface of the sliding part 17 has no aggregate derived from the coat 22 existing on the surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gasket for a prefilled syringe and a prefilled syringe having the gasket.

In recent years, the use of prefilled syringes in which a liquid medicine is preliminarily filled with a syringe has been expanded from the viewpoint that it is excellent in convenience during use and can prevent medical accidents such as mixing of medicines (see Patent Document 1).
In the prefilled syringe, the tip portion to which the injection needle is attached is sealed with a cap. At the time of administration, the cap is removed, the injection needle is attached to the distal end portion, the plunger rod is pushed toward the distal end side, and the gasket is slid to administer the injection solution through the injection needle.

  By the way, the chemical resistance can be improved by laminating an inert film such as a fluororesin on the gasket surface. However, the inert film is easily damaged in the film manufacturing process and the laminated gasket molding process, and if there is a damage after lamination (lamination), the chemical solution may leak through the damage on the film during actual use. In particular, when there is a film scratch parallel to the sliding direction of the gasket, liquid leakage is very likely to occur. Moreover, since resistance (sliding resistance) at the time of inserting a gasket into a syringe barrel is high, you have to apply force when using a prefilled syringe.

  Therefore, in order to improve the sealing performance and slidability of the prefilled syringe, silicone oil or the like is applied to the surface of the gasket or barrel. However, in order to improve the sealing performance, a large amount of silicone oil is required. For this reason, there is a problem that silicone oil is mixed into the chemical solution in the prefilled syringe and the medicinal effect of the chemical solution is lowered.

JP 2005-185747 A

In laminated gaskets, compared to conventional rubber gaskets, resin that is plastically deformed is laminated on the outside of the elastic body made of rubber, thermoplastic elastomer, etc. that constitutes the gasket body. It exists in the tendency for the airtightness of the gasket sliding part which contacts the inner surface of the syringe barrel which becomes to deteriorate.
Conventionally, oil such as silicone oil has been applied to improve the airtightness, but it is difficult to apply uniformly to the resin film laminated on the surface of the laminated gasket, and a large amount is required to improve the airtightness. Had to apply oil.

  The present invention has been made to solve such a problem, and further improves the stability and safety of the chemical solution filled in the syringe, and further improves the sealing performance of the chemical solution, and improves the sealing performance of the chemical solution. The main purpose is to provide

  The invention according to claim 1 is a gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part. A coating made of at least one silicone compound is applied to the surface of the sliding portion, and the maximum height Ry / in each of the circumferential direction of the sliding portion and the direction perpendicular to the circumferential direction (sliding direction) The ratio of / and Ry⊥ before and after the coating is applied (Ry (after coating / before coating)) is 0.9 or less, which is a gasket for prefilled syringes.

  The invention according to claim 2 is a gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part. A coating made of at least one silicone compound is applied to the surface of the sliding portion, and the average roughness Ra / in each of the circumferential direction of the sliding portion and the direction perpendicular to the circumferential direction (sliding direction) A prefilled syringe gasket characterized in that the ratio of Ra and / or Ra⊥ before and after the coating is applied (Ra (after coating / before coating)) is 0.9 or less.

  The invention according to claim 3 is a gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part. A gasket for a prefilled syringe, wherein the surface of the sliding portion is coated with at least one silicone compound and aggregates derived from the coating are not present on the surface.

Invention of Claim 4 is the gasket for prefilled syringes as described in any one of Claims 1-3, Comprising: At least 1 type of a silicone compound contains T unit and Q unit as silicone frame | skeleton, It is characterized by the above-mentioned. It is a gasket for prefilled syringes.
Invention of Claim 5 is a gasket for prefilled syringes of Claim 4, Comprising: Trimethylsiloxy silicic acid or polysilsesquioxane is included as a silicone compound containing T unit and Q unit as a silicone frame | skeleton. This is a prefilled syringe gasket.

Invention of Claim 6 is a gasket for prefilled syringes as described in any one of Claims 1-5, Comprising: Trimethylsiloxy silicic acid and polydimethylsiloxane are used as a silicone compound, It is characterized by the above-mentioned. The gasket for prefilled syringes.
The invention according to claim 7 is a prefilled syringe using the gasket for prefilled syringe according to any one of claims 1 to 6.

  ADVANTAGE OF THE INVENTION According to this invention, the gasket for prefilled syringes which the chemical | medical solution with which the prefilled syringe is filled does not leak can be obtained.

FIG. 1 is a diagram showing a medical syringe according to an embodiment of the present invention in an exploded state. FIG. 2 is a cross-sectional view of a half of a laminated gasket according to an embodiment of the present invention. FIG. 3 is a photomicrograph showing the state of silicone aggregation.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a medical syringe according to an embodiment of the present invention, a so-called prefilled syringe, in an exploded state. In FIG. 1, half of the syringe barrel 11 and the gasket 13 are shown in cross section.
Referring to FIG. 1, a prefilled syringe 10 includes a cylindrical syringe barrel 11, a plunger 12 that can be combined with the syringe barrel 11 and can reciprocate in the syringe barrel 11, and a gasket 13 that is attached to the tip of the plunger 12. Including. The gasket 13 is a so-called laminate gasket including a main body 14 made of an elastic material (such as rubber or elastomer) and a laminate film 15 laminated on the surface of the main body 14. The gasket 13 is provided with two circumferential surface portions (sliding portions) 17 that are in airtight and liquid tight contact with the inner peripheral surface 16 of the syringe barrel 11.

The plunger 12 is made of, for example, a resin plate piece having a cross-shaped cross section, and is provided with a head portion 18 to which a gasket 13 is attached at a tip portion thereof. The head portion 18 is made of a resin integrally formed with the plunger 12 and is processed into a male screw shape.
The gasket 13 has a substantially cylindrical shape with a short axis, and the tip surface thereof has, for example, an obtuse angle shape in which the central portion of the shaft protrudes. A fitting recess 21 having a female thread shape carved in the axial direction from the rear end surface is formed. When the head portion 18 of the plunger 12 is screwed into the fitting recess 21 of the gasket 13, the gasket 13 is attached to the tip of the plunger 12.

FIG. 2 is an enlarged view of only the gasket 13 shown in FIG. 1, and a half of the gasket 13 is shown in cross section.
With reference to FIG. 2, the structure of the gasket 13 which concerns on this embodiment is demonstrated in detail.
The gasket 13 includes a main body 14 and a laminate film 15 laminated on the surface of the main body 14. Further, the gasket 13 is provided with a circumferential surface portion (sliding portion) 17 that is in airtight and liquidtight contact with the inner peripheral surface 16 of the syringe barrel 11. A coat 22 is applied to the surface of the circumferential surface portion (sliding portion) 17.

In this embodiment, two circumferential surface portions (sliding portions) 17 are provided, that is, a front-side circumferential surface portion 17 and a rear-side circumferential surface portion 17, but the circumferential surface portion (sliding portion) 17 is one. There may be only one, or three or more. Further, the shape of the gasket is not limited to the shape of this embodiment.
Next, materials for the main body 14, the laminate film 15, and the coat 22 will be described.

<About the main body 14>
The rubber used as the raw material for the rubber composite forming the main body 14 includes butyl rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, natural rubber, chloroprene rubber, acrylonitrile butadiene rubber and other nitrile rubbers, and hydrogenated nitrile rubber. , Norbornene rubber, ethylene propylene rubber, ethylene-propylene-diene rubber, acrylic rubber, ethylene acrylate rubber, fluorine rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, silicone rubber, urethane rubber, polysulfide rubber, phosphansen rubber Alternatively, 1,2-polybutadiene or the like is used.

One of these may be used alone, or two or more of these may be used in combination.
The rubber used in the rubber composite is not limited to the above, but butyl rubber and / or ethylene-propylene-diene rubber (hereinafter referred to as EPDM rubber) is preferable.
Butyl rubber is preferred because of its excellent gas permeation resistance and water vapor permeation resistance.
A known compound may be used as the butyl rubber, and examples thereof include isobutylene-isoprene copolymer rubber, halogenated isobutylene-isoprene copolymer rubber (hereinafter referred to as “halogenated butyl rubber”), and modified products thereof. Examples of the modified product include a brominated product of a copolymer of isobutylene and p-methylstyrene. Of these, halogenated butyl rubber is more preferable from the viewpoint of easy crosslinking, and chlorinated butyl rubber or brominated butyl rubber is more preferable.

  Also, EPDM rubber is preferable because of its excellent processability. EPDM rubber includes a non-oil-extended EPDM rubber composed only of a rubber component and an oil-extended EPDM rubber containing an extension oil together with the rubber component. Any type of EPDM rubber can be used in the present invention. Examples of the diene monomer in the EPDM rubber include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, and cyclooctadiene.

Further, a combination of halogenated butyl rubber and EPDM rubber is preferable because of good compatibility, excellent gas resistance and water vapor resistance, and excellent processability.
When the rubber composite is a medical rubber product such as a gasket for a syringe as in the present invention, butyl rubber having low gas permeability is preferred as the main component of the rubber. As the crosslinking agent, it is preferable to use triazine derivative crosslinking from the viewpoint of cleanliness.

<About Laminate Film 15>
Although it does not specifically limit as an inert film as the laminate film 15, From the point that favorable chemical-resistance is obtained, polytetrafluoroethylene (PTFE), modified polytetrafluoroethylene (modified PTFE; 4F monomer and a small amount of par Copolymer with fluoroalkoxide), tetrafluoroethylene / ethylene copolymer (ETFE)), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), and polychlorotetrafluoroethylene (PCTFE). At least one kind of fluororesin and / or olefin resin is preferred.

<About coat 22>
In this embodiment, the coat 22 applied to the circumferential surface portion (sliding portion) 17 is made of a silicone compound. The silicone compound is not particularly limited as long as it is a compound having a siloxane bond. Preferably, the silicone skeleton has a structure containing a T unit and a Q unit, and a silicone compound having a branched structure / crosslinked structure is preferably contained. Silicone compounds having a structure containing a T unit and a Q unit as the silicone skeleton include various silicone resins such as methyl silicone resin, phenyl silicone resin, epoxy-modified silicone resin, acrylic-modified silicone resin, polyester-modified silicone resin, and polyphenylsilsesquioxide. And polysilsesquioxanes such as oxane, polymethylsilsesquioxane, and polymethylphenylsilsesquioxane. Of these, methylsilicone resins such as trimethylsiloxysilicic acid and polymethylsilsesquioxane are preferable.

  A preferred embodiment is a mixture of a silicone compound having a branched structure / crosslinked structure having a structure containing a T unit and a Q unit as a silicone skeleton and a linear silicone compound having a D unit as a main structure as a silicone skeleton. More specifically, a mixture of trimethylsiloxysilicic acid and polydimethylsiloxane and a mixture of polymethylsilsesquioxane and polydimethylsiloxane are desirable.

  There is no particular limitation on the mixing ratio of a mixture of a silicone compound having a branched structure / crosslinked structure having a structure containing a T unit and a Q unit as a silicone skeleton and a linear silicone compound mainly having a D unit as a silicone skeleton. Preferably, the silicone compound having a branched structure / crosslinked structure having a structure containing a T unit and a Q unit as the silicone skeleton is 5 to 50% by weight, more preferably 10 to 40% by weight, and still more preferably 20 to 30% by weight. It is. If the blending ratio of the silicone compound having a branched structure / crosslinked structure having a structure containing T units and Q units as the silicone skeleton is too large, the sliding resistance against the barrel inner surface of the gasket may be increased, and the blending ratio is low. If it is too much, it may not be uniformly applied to the gasket surface.

<About gasket molding process>
The gasket of the present invention is a kneaded product obtained by kneading compounded materials at a predetermined compounding ratio using a sealed kneader, an open roll kneader, etc., and producing an unvulcanized rubber sheet with a calendar or a sheet molding machine. A laminated gasket molded sheet can be obtained by stacking an unvulcanized rubber sheet of a constant weight and size and an inert film, placing them in a mold, and molding them with a vacuum press.

The molding conditions are not particularly limited and may be set as appropriate. The molding temperature is preferably 155 to 200 ° C, more preferably 165 to 180 ° C, and the molding time is preferably 1 to 20 minutes, more preferably 3 to 15 minutes, more preferably 5 to 10 minutes. The mold to be used has a smooth mold surface with an arithmetic average roughness Ra of 0.03 μm or less measured at a cutoff value of 0.08 mm of the corresponding part by mirror finishing of the sliding surface forming part. Is preferred. By using such a mold, the laminated rubber member can obtain a molded product smaller than the surface roughness of the original film. Ra is preferably 0.02 μm or less, more preferably 0.015 μm or less.
Thereafter, unnecessary portions are cut and removed from the molded product of the gasket, and thereafter, cleaning, sterilization, drying, and appearance inspection are performed to obtain a finished product of the gasket.

<About gaskets>
As a method for evaluating the uniform presence of the coating of the present invention on the gasket surface, the maximum height Ry / long along the circumferential direction and the circumferential vertical direction (= sliding direction) of the gasket sliding portion before and after the coating. /, Ry⊥ is measured, and the ratio before and after coating (with / without coating) is calculated, along the circumferential direction of the gasket sliding part before and after coating, and the circumferential vertical direction (= sliding direction). A method of measuring the arithmetic average roughness Ra //, Ra ⊥, calculating a ratio before and after coating (with / without coating), and a method of observing the surface with a microscope and confirming the presence or absence of an agglomerated structure is there.

The maximum height and arithmetic average roughness are measured based on JIS B06014: 1994. The cut-off is 0.25 mm.
In the evaluation method based on the maximum height, when the ratio of Ry (with / without coating) <1.00, it can be determined that the surface uniformity is improved by coating compared to before coating. The Ry ratio (with / without coating) in the present invention is preferably 0.90 or less, more preferably 0.75 or less, and still more preferably 0.60 or less.

In the evaluation method based on arithmetic average roughness, when the ratio of Ra (with / without coating) <1.00, it can be determined that the surface uniformity has been improved by coating compared to before coating. The ratio of Ra (with / without coating) in the present invention is preferably 0.90 or less, more preferably 0.75 or less, and even more preferably 0.60 or less.
In the case of the method by microscopic observation, in the present invention, it is preferable that there is no aggregate in the order of μm.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to this embodiment.
<Production Example 1>
An unvulcanized rubber sheet containing chlorinated butyl rubber and a modified PTFE having a thickness of 100 μm were bonded together and molded while being vulcanized and bonded at 175 ° C. for 10 minutes in a vacuum press, thereby obtaining a molded sheet in which a plurality of gasket shapes were molded. . The obtained molded sheet was punched out to obtain a gasket having the shape shown in FIG. The obtained gasket was washed and sterilized and dried to obtain a predetermined gasket.

<Production Example 2>
The ratio of trimethylsiloxysilicic acid (Momentive Performance Materials Japan GK, SR1000) and silicone oil with a viscosity of 20 cSt (Momentive Performance Materials GK, TSF451-20) is 70 / The coating solution was adjusted to 30 wt% so that the concentration of the silicone compound relative to ethyl acetate was 2.5 wt%.

The laminate gasket molded in Production Example 1 and laminated with PTFE was immersed in a solution prepared by adjusting the sliding portion in contact with the inner surface of the barrel, and then dried in air at room temperature to volatilize the solvent. The amount of solution to be applied was set to 7.2 μL / piece per gasket.
<Production Example 3>
In Production Example 2, the viscosity of the silicone oil was changed from 20 cSt to 1000 cSt (Momentive Performance Materials Japan G.K., TSF451-1000). Application was carried out.

<Production Example 4>
In Production Example 2, adjustment of the coating solution and gasket surface were the same as in Production Example 2 except that the viscosity of the silicone oil was changed from 20 cSt to 10,000 cSt (manufactured by Momentive Performance Materials Japan GK, TSF451-1M). Application to was carried out.
<Production Example 5>
As the silicone compound, only a silicone oil having a viscosity of 20 cSt (TSF451-20) was used, and the coating solution was adjusted so that the concentration of the silicone compound with respect to ethyl acetate was 2.5 wt%.

The laminate gasket molded in Production Example 1 and laminated with PTFE was immersed in a solution prepared by adjusting the sliding portion in contact with the inner surface of the barrel, and then dried in air at room temperature to volatilize the solvent. The amount of solution to be applied was set to 7.2 μL / piece per gasket.
<Production Example 6>
In Production Example 5, the coating solution was adjusted and applied to the gasket surface in the same manner as in Production Example 5, except that the viscosity of the silicone oil was changed from 20 cSt to 1000 cSt (TSF451-1000).

<Production Example 7>
In Production Example 5, adjustment of the coating solution and application to the gasket surface were carried out in the same manner as in Production Example 5 except that the viscosity of the silicone oil was changed from 20 cSt to 10,000 cSt (TSF451-1M).
Each of the gaskets obtained in the above production examples was used for various tests shown below.

<Chemical sealability test>
An aqueous solution in which 0.1 wt% of a nonionic surfactant (polysorbate 80) was dissolved was prepared as a liquid to be sealed in the prefilled syringe. A gasket was plugged into a syringe (inner diameter, 6.35 mm) made of plastic (cyclic olefin polymer) having a capacity of 1 mL, and an aqueous solution was injected into the syringe. Then, a rubber cap was put on the syringe tip and placed in an oven at 40 ° C. for 1 week. Thereafter, the sample is taken out from the oven, and a video microscope (DVM5000 manufactured by Leica Microsystems, Inc.) is used to determine whether or not the chemical solution has reached between two sliding portions (hereinafter referred to as valleys) present in the gasket. The measurement magnification was 50 times. When the chemical solution reached the valley, it was determined that there was a leakage of the chemical solution.

<Sliding surface roughness measurement>
The surface roughness of the gasket sliding part was measured with a laser microscope (manufactured by Keyence Corporation, VK-X100). The total magnification was measured at 1000 times, and the maximum height Ry (JIS B06014: 1994) in each of the direction perpendicular to the sliding part circumference (longitudinal direction) and the direction parallel to the sliding part circumference (lateral direction) was measured. Compliance, cut-off 0.25 mm).

Moreover, when measuring the surface roughness, the appearance of the measurement region was measured while rotating the gasket, and the presence or absence of agglomerates derived from the coat was confirmed.
<Example 1>
When the surface roughness of the gasket sliding portion obtained in Production Example 2 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.397 μm and 0.536 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 0.68 and 0.64 in the circumferential vertical direction and circumferential direction, respectively. Moreover, the aggregate was not confirmed. When a chemical solution sealing test was performed on 50 gaskets, no liquid leakage of the chemical solution was observed.

<Example 2>
When the surface roughness of the gasket sliding portion obtained in Production Example 3 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.379 μm and 0.494 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 0.65 and 0.59 in the circumferential vertical direction and circumferential direction, respectively. Moreover, the aggregate was not confirmed. When a chemical solution sealing test was performed on 50 gaskets, no liquid leakage of the chemical solution was observed.

<Example 3>
When the surface roughness of the gasket sliding portion obtained in Production Example 4 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.437 μm and 0.583 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 0.75 and 0.69 in the circumferential direction and circumferential direction, respectively. Moreover, the aggregate was not confirmed. When a chemical solution sealing test was performed on 50 gaskets, no liquid leakage of the chemical solution was observed.

<Comparative Example 1>
When the surface roughness of the gasket sliding portion obtained in Production Example 1 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.586 μm and 0.843 μm, respectively. When a chemical liquid sealing test was performed on 50 gaskets, there were 6 gaskets leaking chemical liquid.

<Comparative Example 2>
When the surface roughness of the gasket sliding portion obtained in Production Example 5 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.770 μm and 0.919 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 1.31 and 1.09 in the circumferential vertical direction and circumferential direction, respectively. Aggregates were also confirmed. When a chemical solution sealing test was performed on 50 gaskets, the number of gaskets leaking chemical solutions was four.

<Comparative Example 3>
When the surface roughness of the gasket sliding portion obtained in Production Example 6 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.827 μm and 0.981 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 1.41 and 1.16 in the circumferential vertical direction and circumferential direction, respectively. Aggregates were also confirmed. When a chemical liquid sealing test was performed on 50 gaskets, there were 5 gaskets leaking chemical liquid.

<Comparative example 4>
When the surface roughness of the gasket sliding portion obtained in Production Example 7 was measured, the maximum heights in the circumferential vertical direction and the circumferential direction were 0.929 μm and 1.098 μm, respectively. The ratio of the maximum height before and after coating (Ry (with / without coating)) was 1.59 and 1.30 in the circumferential vertical direction and circumferential direction, respectively. Aggregates were also confirmed. When a chemical liquid sealing test was performed on 50 gaskets, there were 5 gaskets leaking chemical liquid.
Table 1 below summarizes the above.

<Conclusion>
It was confirmed that by applying the coating of the present invention to the gasket surface (the surface of the sliding portion), a uniform coating was realized and the airtightness was greatly improved.

DESCRIPTION OF SYMBOLS 10 Prefilled syringe 11 Syringe barrel 12 Plunger 13 Gasket 14 Main body 15 Laminate film 17 Inner peripheral surface part (sliding part)
22 coats

Claims (7)

A gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part,
A coat made of at least one silicone compound is applied to the surface of the sliding portion,
The ratio (Ry (after coating / before coating)) before and after the coating of the maximum heights Ry // and Ry⊥ in the circumferential direction of the sliding portion and the direction perpendicular to the circumferential direction (sliding direction), respectively. , Both are 0.9 or less, The gasket for prefilled syringes characterized by the above-mentioned. A gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part,
A coat made of at least one silicone compound is applied to the surface of the sliding portion,
The ratio (Ra (after coating / before coating)) before and after the coating of the average roughness Ra // and RaＲ in the circumferential direction and the direction perpendicular to the circumferential direction (sliding direction) of the sliding part , Both are 0.9 or less, The gasket for prefilled syringes characterized by the above-mentioned. A gasket for a prefilled syringe comprising a wetted part and a sliding part in contact with the inner surface of the syringe barrel, wherein an inert film is laminated on the surface of the wetted part and the sliding part,
A gasket for a prefilled syringe, wherein the surface of the sliding portion is coated with at least one silicone compound, and aggregates derived from the coating are not present on the surface. The prefilled syringe gasket according to any one of claims 1 to 3,
A gasket for prefilled syringes, wherein at least one kind of silicone compound contains T units and Q units as a silicone skeleton. The prefilled syringe gasket according to claim 4,
A gasket for a prefilled syringe, comprising trimethylsiloxysilicic acid or polysilsesquioxane as a silicone compound containing T units and Q units as a silicone skeleton. It is a gasket for prefilled syringes as described in any one of Claims 1-5,
A gasket for a prefilled syringe, wherein trimethylsiloxysilicic acid and polydimethylsiloxane are used as a silicone compound.   The prefilled syringe which uses the gasket for prefilled syringes as described in any one of Claims 1-6.