PFAS-free syringe plunger stopper with curved internal rib region

Abstract

Provided herein are stoppers that are PFAS-free or substantially PFAS-free and are adapted for mounting with a plunger rod for use within a syringe barrel. The stopper includes a body portion defining a proximal end and a distal end, the proximal end being configured to engage with the distal end of the plunger rod for securing the stopper to the plunger rod. The stopper also includes a plurality of ribs, each extending from the outer surface of the body portion around the outer circumference of the body portion, the plurality of ribs including at least a first rib and a second rib spaced apart from the first rib. The stopper also includes curved inter-rib regions positioned between each pair of adjacent ribs of the plurality of ribs, the outer surface of the body portion being curved radially inward.

Description

[Technical Field]

[0001] This disclosure relates, in general, to a plunger stopper for use with a syringe, and more specifically, to a PFAS-free plunger stopper having a curved internal rib region. [Background technology]

[0002] This application claims priority to European Patent Application No. 23315131.5, filed on 28 April 2023, entitled “PFAS-free syringe plunger stopper with curved internal rib region,” and this application also claims priority to European Patent Application No. 2318770.3, filed on 26 July 2023, entitled “PFAS-free syringe plunger stopper with curved internal rib region,” and the entire disclosures of both applications are incorporated herein by reference.

[0003] Medical injection devices such as syringes are used in a variety of settings to administer liquids (e.g., drugs or medications) to patients. Many syringes are supplied as pre-filled syringes, which offer the convenience of quickly delivering the liquid within them to the patient without the need to first draw the medication from another container and measure its volume. To distribute fluid, a pre-filled syringe typically includes a syringe barrel with a plunger assembly inserted through the open proximal end of the barrel, and an opening at the opposite distal end fitted to receive a needle, thereby injecting the fluid into the patient. The plunger assembly typically includes an elongated plunger rod extending out of the barrel and a plunger head or stopper located at the distal end of the plunger rod. The stopper or plunger stopper is typically made of elastomer material and fitted to ensure the integrity of the syringe's container closure when the stopper is inserted into the syringe.

[0004] Existing stopper designs include a stopper body having a tail portion positioned at its proximal end, adapted to attach to the distal end of a plunger rod, and a head portion positioned at its distal end, adapted to engage with the syringe barrel. The head portion of the stopper may include a plurality of annular outwardly projecting ribs formed on its outer cylindrical wall, the ribs forming a seal with the syringe barrel to ensure the integrity of the syringe container closure. A series of two or three ribs may be spaced longitudinally apart along the stopper body, for example, with each pair of adjacent ribs separated by an internal rib region provided between them. The internal rib region is generally formed to present a cylindrical outer surface on the stopper of the internal rib inserted radially inward from the rib (i.e., a “straight” internal rib region).

[0005] While existing stoppers with the structure described above are effective in maintaining the integrity of the closure within the syringe, it is recognized that such stoppers can present problems during the syringe closure process, such as during insertion of the stopper into the syringe barrel while the vent tube is being sealed. Specifically, the design of the stopper, particularly the design of the straight internal rib region, can increase friction between the stopper and the syringe barrel, making stopper insertion more difficult. This increased friction may be particularly true for stoppers that are formed to be free of perfluoroalkyl and polyfluoroalkyl substances (PFAS).

[0006] Therefore, there is a need in the art for a plunger stopper for use with a syringe, and the stopper is configured to reduce the amount of friction present between the stopper and the syringe barrel during the stopper insertion process. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 10,751,473 [Overview of the project] [Means for solving the problem]

[0008] Provided herein are stoppers that are free of or substantially free of perfluoroalkyl and polyfluoroalkyl substances (PFAS) and are adapted for mounting with a plunger rod for use in a syringe barrel. The stopper includes a body portion defining a proximal end and a distal end, the proximal end being configured to engage with the distal end of the plunger rod for securing the stopper to the plunger rod. The stopper also includes a plurality of ribs, each extending from the outer surface of the body portion around the outer circumference of the body portion, the plurality of ribs including at least a first rib and a second rib spaced apart from the first rib. The stopper also includes internal rib regions positioned between each pair of adjacent ribs of the plurality of ribs, the internal rib regions being characterized by including curved internal rib regions where the outer surface of the body portion curves radially inward.

[0009] In certain configurations, the stopper does not include PFAS.

[0010] In certain configurations, the stopper contains PFAS at a concentration of 200 ppm (200 parts per million) or less, preferably 50 ppm (50 parts per million) or less.

[0011] In a particular configuration, the internal rib region includes a first abutment region adjacent to the first rib, a second abutment region adjacent to the second rib, and a central region located between the first and second abutment regions, where the first and second abutment regions are generally flat, and the central region curves radially inward from the first and second abutment regions.

[0012] In certain configurations, the first and second boundary regions are defined by the outer diameter D of the maximum internal rib region. 最大_内部-リブ It provides, and the center point of the central region is the outer diameter D of the minimum internal rib region. 最小_内部-リブ To provide.

[0013] In a specific configuration, the first and second ribs have an outer diameter, D 外部_リブ and

[0014]

Number

[0015] the ratio of is between the values of 1.03 and 1.30.

[0016] In a specific configuration, the radius of curvature of the central region is between 30 mm and 600 mm.

[0017] In a specific configuration, each of the first rib and the second rib includes a radially outward contact surface, and the width of the contact surface is 0.2 to 10 mm, preferably 0.2 mm to 1.5 mm.

[0018] In a specific configuration, the stopper also includes a coating applied to at least the radially outward contact surfaces of the first and second ribs to reduce the friction between the first and second ribs and the syringe barrel.

[0019] In a specific configuration, the stopper includes a third rib spaced apart from the second rib, the third rib extends around the outer periphery of the body portion from the outer surface of the body portion, and includes a second inner rib region disposed between the second rib and the third rib, and the second inner rib region includes a curved inner rib region where the outer surface of the body portion curves radially inward.

[0020] Also, in this specification, a syringe includes a syringe barrel having a barrel proximal end and a barrel distal end and defining a chamber configured to contain fluid therein, and a plunger assembly axially movable between a storage position and a forward position within the chamber of the syringe barrel. The plunger assembly includes a plunger having a plunger proximal end and a plunger distal end, and a stopper fixed to the plunger distal end. The stopper does not contain or substantially does not contain perfluoroalkyl and polyfluoroalkyl substances (PFAS). The stopper includes a body portion defining a proximal end and a distal end. The proximal end is configured to mate with the distal end of the plunger rod to fix the stopper to the plunger rod. The stopper also includes a plurality of ribs each extending around the outer periphery of the body portion from the outer surface of the body portion. The plurality of ribs includes at least a first rib and a second rib spaced apart from the first rib. The stopper also includes an internal rib region disposed between each pair of adjacent ribs of the plurality of ribs. The internal rib region includes a curved internal rib region where the outer surface of the body portion curves radially inward.

[0021] In a particular configuration, the internal rib region includes a first boundary region disposed adjacent to the first rib, a second boundary region disposed adjacent to the second rib, and a central region disposed between the first boundary region and the second boundary region. Each of the first boundary region and the second boundary region is generally flat, and the central region curves radially inward from the first boundary region and the second boundary region.

[0022] In a particular configuration, the stopper contains PFAS in the range of 0 to 200 ppm, preferably 0 to 50 ppm.

[0023] In a particular configuration, the interference between the first and second ribs and the syringe barrel is in the range of 1.5 to 20% as determined by interference = ((D 外部_リブ / ID バレル ) -  1) × 100, where D 外部_リブThis is the outer diameter of the first and second ribs, ID バレル This is the inner diameter of the syringe barrel. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a perspective view of a syringe in which an embodiment of the present disclosure may be implemented. [Figure 2] Figure 2 is an exploded view of the syringe shown in Figure 1. [Figure 3] Figure 3 is a side view of a stopper included in the syringe of Figure 1, according to a non-limiting embodiment described herein. [Figure 4] This is a side cross-sectional view of the stopper in Figure 3, taken along line 4-4. [Figure 5] This is a side cross-sectional view of a stopper according to another non-limiting embodiment described herein. [Modes for carrying out the invention]

[0025] The following description is provided to enable those skilled in the art to create and use the described embodiments intended for carrying out the invention. However, various modifications, equivalents, variations, and substitutes will be readily apparent to those skilled in the art. Any and all such modifications, variations, equivalents, and substitutes are intended to fall within the spirit and scope of the invention.

[0026] Hereinafter, for illustrative purposes, “top,” “bottom,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” “horizontal,” “vertical,” and their derivatives shall be used in relation to the present invention as oriented in the drawings. However, it should be understood that the present invention may presuppose various alternative modifications unless expressly otherwise specified. It should also be understood that the specific devices shown in the accompanying drawings and described in the following specification are merely exemplary embodiments of the present invention. Therefore, specific dimensions and other physical features relating to the embodiments disclosed herein should not be considered restrictive.

[0027] In this disclosure, the distal end of a component or device means the end furthest from the user's hand when the component or device is in use, i.e., when the user is holding the syringe in preparation for or during use, and the proximal end means the end closest to the user's hand. Thus, in a syringe, for example, the distal end is its end containing the needle (or Luer connector), and the proximal end is where the user engages with the plunger (i.e., the plunger thumb press). Similarly, in this application, the terms “distally” and “distally” mean the direction toward the distal tip of the syringe, and the terms “proximal” and “proximal” mean the direction opposite to the direction of the distal tip of the syringe (i.e., the direction of the plunger thumb press).

[0028] Referring to Figures 1 and 2, Figures 1 and 2 illustrate non-limiting embodiments of syringe 10 in which aspects or embodiments of the present disclosure may be implemented. According to some aspects of the present disclosure, syringe 10 may be provided as a pre-filled syringe, which provides the convenience of rapidly delivering the liquid within it to the patient without the need to first draw the drug from another container and measure its volume.

[0029] As shown in Figures 1 and 2, the syringe 10 generally includes a syringe barrel 12 and a plunger assembly 14. The plunger assembly 14 is movable within the syringe barrel 12 to an advanced position along its longitudinal axis to facilitate the administration of an injectable fluid (e.g., a drug) to a patient. The syringe barrel 12 is generally formed from a cylindrical outer wall 16 and an end member 18 that collectively define a chamber 20 for holding fluid therein. The syringe barrel 12 includes an open proximal end 22 configured to receive the plunger assembly 14 therein and a distal end 24 where the end member 18 is located. The proximal end 22 of the syringe barrel 12 may include a flange 26 to facilitate the handling and positioning of the syringe 10 and to maintain the relative position of the syringe barrel 12 with respect to the plunger assembly 14 during drug administration. At the distal end 24, the end member 18 may include a shoulder portion 28 that narrows relative to the cylindrical outer wall 16 and a hub portion 30 that extends distally from the shoulder portion 28. The hub portion 30 is formed as a partially hollow member that fluidly communicates with the chamber 20 and defines a channel 32 through which it passes. The needle 34 is attached to the hub portion 30 in the channel 32 by being bonded to the hub portion 30 or otherwise fixed to it.

[0030] According to some aspects of the present disclosure, the syringe 10 may further include a cover 35 that connects to the hub portion 30 of the syringe barrel 12 to protect the needle 34. The cover 35 includes a closed distal end and an open proximal end, the open proximal end allowing for the placement of a cover that covers the hub portion 30 and the needle 34. Although not shown in Figures 1 and 2, the cover 35 may include an outer casing made of a rigid material and an inner casing made of a flexible material, so that when the cover 35 is attached to the hub portion 30 of the syringe 10, the needle 34 can be safely housed within (or engaged with) the cover 35.

[0031] The plunger assembly 14 of the syringe 10 is formed from an elongated plunger rod 36 (more commonly referred to as "plunger 36" as used below) and a plunger head or stopper 38. The plunger 36 may include a body 40 extending between the proximal end 42 and the distal end 44 of the plunger. In some embodiments, the body 40 may include a plurality of elongated vanes or walls 46 extending axially along its length between the proximal end 42 and the distal end 44 of the plunger. A thumb press 48 is positioned on the proximal end 42 of the plunger and engaged by the user's thumb (or other fingers) to apply distal force to the plunger assembly 14, thereby moving the plunger 36 relative to the syringe barrel 12. In some embodiments, an extension member 50 (e.g., a threaded cylindrical member) is positioned on the distal end 44 of the plunger and configured to engage with the stopper 38. In other embodiments, the distal end 44 of the plunger may include a female receptacle formed therein, which is configured to receive and connect a projection (e.g., a pin) extending proximal from the stopper 38 such that the projection and the receptacle engage via threads.

[0032] The stopper 38 of the plunger assembly 14 is positioned at the distal end 44 of the plunger so as to be movable with the plunger 36 within the chamber 20 of the syringe barrel 12. The stopper 38 may be made of a different material from the material of the plunger 36 and may form a seal with the syringe barrel 12 as the syringe barrel 12 advances through it. In some embodiments, the stopper 38 is formed of an elastomer material such as butyl, styrene-butadiene, or isoprene, as a non-limiting example. In other embodiments, instead, the stopper 38 may be formed of a polymer material such as a crosslinked elastomer or thermoplastic elastomer, as a non-limiting example.

[0033] According to aspects of this disclosure, whether the stopper 38 is formed of an elastomer material or a polymer material, the stopper is formed to be free of or substantially free of perfluoroalkyl and polyfluoroalkyl substances (PFAS) (commonly known as “PFAS-free” materials) that may leach into the drug or other solution stored in the pre-filled syringe 10. As defined herein, “PFAS-free or substantially free” or “PFAS-free” stopper 38 is understood to mean a material that is completely free of PFAS and / or may contain trace amounts of PFAS. In exemplary embodiments, the stopper 38 is considered substantially PFAS-free if it contains 200 p-parts per million or less of PFAS (i.e., 200 ppm or less), and preferably 50 ppm or less of PFAS (i.e., 50 ppm or less). In general, the materials constituting Stopper 38 are understood to comply with the rules and regulations set forth by the European Union regarding restrictions surrounding PFAS as determined by the European Chemicals Agency (ECHA), the ECHA's proposed regulations, ECHA Annex XV Restriction Report - Proposed Restrictions - Substance Name(S): Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS), Version 2, dated March 22, 2023. Therefore, if Stopper 38 contains traces of PFAS higher than the above 200 ppm (e.g., 300 ppm or 400 ppm as a non-limiting example), it is assumed that Stopper 38 could still be considered "substantially PFAS-free" if such values ​​are found to be permissible / compliant with the final guidelines or regulations set forth by ECHA.

[0034] Continuing with reference to Figures 1 and 2, and then to Figures 3 and 4, the structure of the stopper 38 is shown in more detail according to an aspect or embodiment of the present disclosure. The stopper 38 is defined by a body 52 which includes an open proximal end 54 that engages with the distal end of the plunger 36 and a closed distal end 56 configured to engage with the barrel 12 of the syringe 10. The closed distal end 56 of the body 52 generally includes a cylindrical portion 58 and a roof portion 60 that extends distally from the cylindrical portion 58. In one embodiment, the roof portion 60 is configured as a conical portion that extends distally from the cylindrical portion 58 to the tip 62 in order to provide the closed distal end 56. However, it is recognized that the roof portion 60 may have other suitable shapes, such as being formed as a flat surface or a domed surface, as other non-limiting examples.

[0035] As shown in Figure 4, the body 52 of the stopper 38 is substantially hollow and is dimensioned and configured to receive the extension member 50 of the plunger 36. The body 52 of the stopper 38 defines an internal cavity 64, which is generally defined between the majority of the open proximal end 54 and the closed distal end 56 of the body 52. ​​In some embodiments, as described above, the internal cavity 64 includes a threaded inner surface 66 configured to receive and fit the threaded extension member 50 of the plunger 36. In other embodiments, the internal cavity 64 may define an inner contour surface having a notch configured to receive the flanged extension member of the plunger 36, the flanged extension member engaging with the notch to hold the extension member 50 within the internal cavity 64.

[0036] Referring further to FIGS. 3 and 4, the outer surface 68 of the cylindrical portion 58 of the body 52 includes a plurality of ribs 70, 72 formed thereon that extend circumferentially around the entire outer surface 68 of the cylindrical portion 58. In the illustrated embodiment, the plurality of ribs 70, 72 include a first rib 70 disposed toward the proximal end 54 of the body 52 and a second rib 72 disposed toward the distal end 56 of the body 52, and the first rib 70 is longitudinally spaced from the second rib 72 on the cylindrical portion 58 to form an internal rib region 74 therebetween. The stopper 38 is shown in FIGS. 3 and 4 as including only two ribs 70, 72 (i.e., the first rib 70 and the second rib 72) formed thereon, and the stopper 38 can be configured to include more ribs, such as three ribs, while including a third rib 75 shown in FIG. 5, and it is recognized that the stopper 38 includes an internal rib region 74 provided between each adjacent pair of ribs.

[0037] According to an embodiment of the present disclosure, the structure of each of the first rib 70 and the second rib 72 can be controlled to achieve a desired interaction between the stopper 38 and the barrel 12. According to one aspect of the ribs 70, 72, the ribs 70, 72 extend radially outward from the internal rib region 74 of the cylindrical portion 58 by a desired distance (i.e., the thickness of the rib) so as to function as bearing points against the inner surface of the syringe barrel 12. In some embodiments, the outer diameter, D 外部_リブ of the rib is controlled based on the inner diameter, ID バレル of the barrel 12 to provide a desired amount of interference between the stopper 38 and the barrel 12. As an example, the thickness and outer diameter D 外部_リブ of the rib are such that interference = (D 外部_リブ / ID バレルThe interference between the stopper 38 and the syringe barrel 12 is in the range of 1.5 to 20%, as determined by (-1) × 100. According to another embodiment of the ribs 70, 72, the respective widths of the first rib 70 and the second rib 72 that contact the syringe barrel 12 (i.e., the radially outward contact surfaces 76 of the ribs 70, 72) are between 0.2 mm and 10 mm, preferably between 0.2 mm and 1.5 mm. According to yet another embodiment of the ribs 70, 72, each of the first rib 70 and the second rib 72 may include grooving or surface texturing formed thereon, as described in Patent Document 1 incorporated herein by reference. The grooving or surface texturing is formed on the radially outward contact surfaces 76 of the ribs 70, 72 so as to locally reduce the contact surface and locally increase the contact pressure when compressed.

[0038] According to aspects of this disclosure, an internal rib region 74 located between the first rib 70 and the second rib 72 (and, if there are three or more ribs, between other adjacent pairs of ribs) is formed to provide a curved outer surface 68 to a section / region of the cylindrical portion 58 of the body 52. ​​The internal rib region 74 includes boundary regions 78, i.e., a first boundary region 78a and a second boundary region 78b, at each of its ends adjacent to the first rib 70 and the second rib 72, and each of the boundary regions 78 exhibits a generally flat surface. The central region 80 is located between the boundary regions 78 that curve radially inward from the boundary regions 78, and the maximum outer diameter D of the internal rib region 74 最大_内部-リブ The boundary region 78 is provided, and the minimum outer diameter D of the internal rib region 74 最小_内部-リブ The central region 80 is provided along the central region 80 (i.e., to the longitudinal midpoint 82 of the central region 80). In some embodiments, the radius of curvature of the curved central region 80 is between 30 mm and 600 mm, and the curved central region 80 is provided by a rib, D 最小_内部-リブ The ratio of the minimum outer diameter of the internal rib region 74 to the outer diameter of D 外部_リブ -that is-

[0039]

number

[0040] It is configured so that the value is between 1.03 and 1.30.

[0041] According to aspects of the present disclosure, the stopper 38 may further include an outer surface or coating 84 applied to that portion, such as on the sealant or its sliding surface, i.e., on the contact surfaces 76 of the first rib 70 and the second rib 72, and / or on the roof portion 60. The coating 84 may be configured to reduce friction between the stopper 38 and the barrel 12 as the stopper 38 moves within the syringe 10. The coating 84 is formed of a PFAS-free material (or substantially PFAS-free material) that may leach into the drug or other solution contained in the pre-filled syringe 10. As stated above, according to aspects of the present disclosure, the coating 84 is considered PFAS-free or substantially PFAS-free if it contains 0 to 200 ppm of PFAS, and / or otherwise complies with the guidelines or regulations set forth by ECHA regarding acceptable amounts of PFAS.

[0042] According to aspects of this disclosure, the configuration of the internal rib region 74 as a radially curved surface reduces the amount of friction present when inserting the stopper 38 into the barrel 12, i.e., during a closure process such as closing a vent pipe. That is, by including the curved internal rib region 74 on the stopper 38, the contact pressure between the stopper 38 and the barrel 12 is reduced, particularly within the internal rib region 74, thereby reducing friction between them. In some embodiments, the inclusion of the curved internal rib region 74 on the stopper 38 reduces the friction between the stopper 38 and the barrel 12 by 10 to 50% (or more), depending on the stopper sizing rules applied, compared to a stopper 38 having a straight / linear internal rib region 74. In some embodiments, the stopper may be further improved by adding a sliding coating 84 on the ribs 70, 72 (i.e., sliding may be optimized and friction may be reduced). The inclusion of the gliding coating 84 on the ribs 70, 72 also eliminates or significantly reduces the use of such lubricants when inserting the stopper 38 into the syringe 10 via the vent tube stopper process (e.g., 0.02 mg / cm³). 2 The following method minimizes the need for the use of a separate lubricant on the stopper 38.

[0043] Therefore, advantageously, embodiments of the present invention relate to a stopper having spaced-out first and second ribs formed thereon, extending from the outer surface of the body portion of the stopper and extending around the outer circumference of the body portion. The inner rib region of the outer surface between the first and second ribs is configured as a curved inner rib region where the outer surface of the body portion curves radially inward. The curved inner rib region reduces the amount of friction present when inserting the stopper into the syringe barrel, such as during the venting process, because the curved inner rib region reduces the contact pressure between the stopper and the barrel, thereby reducing friction between the stopper and the barrel. The curved inner rib region is therefore beneficial in enabling the venting process, especially for stoppers having a structure / composition that does not contain PFAS.

[0044] This disclosure has been described in detail for illustrative purposes based on what is currently considered to be the most practical and preferred embodiments or aspects, but such details are for that purpose only, and this disclosure is not limited to the disclosed embodiments or aspects, but rather intended to encompass modifications and equivalent arrangements that fall within the spirit and scope of the appended claims. For example, this disclosure is intended to be, wherever possible, to allow one or more features of any embodiment to be combined with one or more features of any other embodiment.

Claims

1. A stopper that is free of or substantially free of perfluoroalkyl and polyfluoroalkyl substances (PFAS) and is adapted for attachment to a plunger rod for use in a syringe barrel, A main body portion defining a proximal end and a distal end, wherein the proximal end is configured to fit with the distal end of the plunger rod in order to fix the stopper to the plunger rod, Each of the plurality of ribs extends from the outer surface of the main body portion around the outer circumference of the main body portion, and the plurality of ribs includes at least a first rib and a second rib spaced apart from the first rib, An internal rib region is located between each pair of adjacent ribs of the plurality of ribs, and the internal rib region includes an internal rib region in which the outer surface of the main body portion is curved radially inward, A stopper that includes this.

2. The stopper according to claim 1, wherein the stopper does not contain PFAS.

3. The stopper according to claim 1, wherein the stopper contains PFAS at 200 ppm or less, preferably PFAS at 50 ppm or less.

4. The internal rib region comprises a first boundary region located adjacent to the first rib, A second boundary region located adjacent to the second rib, A central region disposed between the first boundary region and the second boundary region, The stopper according to any one of claims 1 to 3, wherein each of the first boundary region and the second boundary region is generally flat, and the central region curves radially inward from the first boundary region and the second boundary region.

5. The first boundary region and the second boundary region have an outer diameter D of the maximum internal rib region. 最大_内部-リブ The central point of the central region is the outer diameter D of the minimum internal rib region. 最小_内部-リブ The stopper according to claim 4, which provides...

6. The first rib and the second rib have an outer diameter, D 外部_リブ It has, [Math 1] The stopper according to claim 5, wherein the ratio is a value between 1.03 and 1.

30.

7. The stopper according to any one of claims 4 to 6, wherein the radius of curvature of the central region is between 30 mm and 600 mm.

8. The stopper according to any one of claims 1 to 7, wherein each of the first rib and the second rib includes a radially outward contact surface, the width of the contact surface being 0.2 to 10 mm, preferably 0.2 mm to 1.5 mm.

9. The stopper according to any one of claims 1 to 8, comprising a coating applied to at least the radially outward contact surfaces of the first rib and the second rib in order to reduce friction between the first rib and the second rib and the syringe barrel.

10. The stopper according to any one of claims 1 to 9, comprising a third rib spaced apart from the second rib, wherein the third rib extends from the outer surface of the body portion around the outer circumference of the body portion, and the second internal rib region is located between the second rib and the third rib, and the second internal rib region includes a curved internal rib region in which the outer surface of the body portion curves radially inward.

11. A syringe barrel having a proximal end and a distal end, defining a chamber configured to contain fluid, and A plunger assembly that is movable in the axial direction between a retracted position and an advanced position within the chamber of the syringe barrel, The plunger assembly comprises a plunger having a proximal end and a distal end, The stopper according to claim 1, which does not contain or substantially contains perfluoroalkyl and polyfluoroalkyl substances (PFAS) Plunger assembly including Syringe containing.

12. The internal rib region of the stopper is A first boundary region positioned adjacent to the first rib, A second boundary region located adjacent to the second rib, A central region is located between the first boundary region and the second boundary region. Includes The first boundary region and the second boundary region are generally flat, and the central region curves radially inward from the first and second boundary regions. The syringe according to claim 11.

13. The syringe according to claim 12, wherein the stopper contains 0 to 200 ppm of PFAS, preferably 0 to 50 ppm of PFAS.

14. The interference between the first rib and the second rib and the syringe barrel is: interference = ((D 外部_リブ / ID バレル As determined by () - 1) × 100, it is in the range of 1.5 to 20%, D 外部_リブ The outer diameters of the first rib and the second rib are, ID バレル The syringe according to any one of claims 11 to 13, wherein is the inner diameter of the syringe barrel.

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