Syringe assembly with indicia on plunger for dosing

Abstract

A syringe assembly (100) is provided, the syringe assembly (100) comprising a syringe barrel (106) comprising a syringe barrel body (105) having an axial passage through the syringe barrel (106), where the syringe barrel body is at least partially transparent, and the syringe barrel comprises at least one indicia (110). The assembly also includes a plunger (102) having a visible indicia connected to or disposed on a plunger body (103), where the visible indicia is at a distance from a piston (118) of the plunger. The indicia of the plunger is visible through at least a portion of the barrel body. The liquid can be dosed accurately by aligning the mark on the plunger body with the mark on the syringe.

Description

Technical Field

[0001] The present invention relates to the field of syringe assemblies, which comprise a barrel and a plunger having a piston at the distal end of the plunger. Background Art

[0002] Liquids, such as liquid medications, are typically provided in a syringe assembly that uses a needle to provide a predetermined amount of liquid to, for example, a body part of a patient. Many liquid medications must be administered in a specific volume. For example, in the field of ophthalmology, the volume of liquid medication used must be accurately measured, such as about 0.05 mL or even less. The syringe assembly typically includes a syringe and a plunger that can be moved through the syringe. A piston is provided at the distal end of the plunger, which forms a seal with the inner wall of the syringe. The piston can also be referred to as a stopper.

[0003] In order to allow the user to determine the volume of the liquid drug in the syringe assembly, one or more markings may be provided on the syringe barrel. Since the volume of the liquid drug in the syringe assembly is determined by the position of the piston in the syringe barrel of the syringe assembly, the distal end of the piston may be aligned with the markings on the syringe barrel to determine the volume of the liquid drug in the syringe assembly. In order to facilitate visual identification of the piston in the syringe barrel, the piston is typically provided in a darker color than the plunger body to which the piston is connected. For example, the piston may be black, while the plunger body may be white or even transparent. Summary of the invention

[0004] It has been observed that, particularly when the volume of liquid in the syringe assembly is small, e.g., on the order of several milliliters or even tens of milliliters, a small displacement of the piston in the barrel of the syringe assembly may result in a relatively significant change in the volume of the liquid in the syringe assembly. This may be caused, for example, by a practical minimum value for the inner diameter of the barrel, e.g., due to manufacturing limitations; and / or a minimum volume of the syringe, e.g., 1 mL, as specified by industry standards; and / or a minimum size that the syringe must have in order to be properly held.

[0005] Furthermore, it has been observed that the user may have difficulty aligning the piston with the markings on the barrel, particularly when the distal end of the piston does not form a flat surface and / or when the portion of the distal end of the piston that forms a seal with the inner wall of the barrel is not the outermost distal end of the piston, for example, when the piston has a curved or convex end surface.

[0006] Furthermore, it has been observed that the skirt of the syringe at the distal end of the syringe may hinder or make it difficult to print markings at or near the distal end of the syringe, in particular the zero marking. However, it may be preferred to use such a skirt, for example, in order to connect the needle hub to the distal end of the syringe by a threaded connection, such as a known Luer lock.

[0007] If the needle hub is mounted on the syringe (e.g., using a Luer slip connection), the markings at or near the distal end of the syringe may be covered by the needle hub. This may make it difficult or even impossible for the user to see the markings, and / or to align the piston with such markings.

[0008] In general, it is further observed that the distal end of the syringe may taper towards the distal end of the syringe, for example, to comply with the well-known Luer lock or Luer taper standard. Printing a mark, such as a zero mark, on such a tapered portion of the syringe may be technically complex. This may make printing on the tapered portion economically unfeasible.

[0009] One object is to increase the precision and / or accuracy with which a user can determine the volume of liquid present in a syringe assembly, particularly when visually determining the volume. Thus, one object is to increase the precision and / or accuracy with which a user can dose a volume of liquid.

[0010] A first aspect provides a plunger for a syringe assembly, the plunger comprising: a plunger body having a piston located at or near a distal end of the plunger; a visible mark connected to or disposed on the plunger body, wherein the visible mark is spaced a distance from the piston. The plunger is generally configured to insert the plunger body into a syringe in a manner such that the piston is first inserted into the syringe.

[0011] Typically, a portion of the plunger body extends beyond the proximal end of the barrel, thereby allowing a user to push the plunger further into the barrel and / or pull the plunger away from the distal end of the barrel.

[0012] Usually, the plunger is made of a plunger body and a piston. In addition, generally speaking, the plunger body and the piston can be separate elements, such as can be connected to each other by a threaded connection or an adaptation connection, or can even be separate elements when in use.

[0013] When the plunger body and the piston are separate components, the plunger body and the piston move together at least when in use, for example, when the plunger is inserted into the syringe toward the distal end of the syringe. In this case, whether the plunger body is connected to the piston or not, the plunger body can be used to push the piston further into the syringe, for example, to expel liquid from the syringe.

[0014] Alternatively, the plunger body and the piston may be formed as a single body, for example in an injection molding process using a single material or multiple types of materials.The plunger body itself may be a single body, or may comprise a plurality of connected bodies.

[0015] Since the visible mark is at a distance from the piston, the piston of the plunger no longer has to serve as a visible mark that has to be aligned with the mark of the syringe. In other words, the mark can be at a distance from a part of the plunger (e.g., the piston) that forms a substantially liquid seal with the syringe. Thus, for example, the piston of the plunger can have any shape, including curved, convex or even concave shapes, without making it more difficult for the user to measure a specific volume of liquid in the syringe. It has been observed that when a curved, convex or even concave shape has to be aligned with a mark on the syringe, it may be difficult for the user to determine which part of the curved, convex or even concave shape, such as the minimum or maximum value of the shape, has to be aligned with the mark.

[0016] Since the piston no longer has to serve as a mark that aligns with the mark on the syringe, more freedom can be provided in how the marking of the plunger can be shaped and what size it can be. This in turn can allow for more accurate dosing because the freedom in how the marking of the plunger can be shaped and what size it can be can now be independent of the shape and / or size of the piston.

[0017] The visible marking of the plunger is visible through the transparent portion of the syringe during use, and is therefore visible to the user. When the marking of the plunger is visible through the syringe body, the user can align the marking of the plunger with the marking of the syringe to ensure that the desired volume of liquid is present in the syringe, or that there is substantially no liquid volume in the syringe. Preferably, the marking of the plunger is a thin line, the thickness of which is, for example, less than 10% of the axial length of the plunger, or even less than 1% of the axial length.

[0018] When the visible mark of the plunger is connected to or arranged on the plunger body, the visible mark can move together with the plunger body. Therefore, when the plunger body moves axially, for example in a syringe, the visible mark also moves axially.

[0019] The marking of the plunger can be or include, for example, a line oriented substantially perpendicular to the extension direction of the plunger, which line can partially surround or preferably completely surround the plunger body. When the marking completely surrounds the plunger body, the marking can be visible from any viewing direction.

[0020] Additionally, or alternatively, the markings on the plunger may be or include, for example, one or more arrows, triangles, circles, other symbols, or any combination thereof.

[0021] The marking may be visible on the plunger by making the marking different in color from the segment of the plunger body axially adjacent to the marking. For example, the marking may be a generally dark color, such as black. The segment of the plunger body axially adjacent to the marking may be a generally light color, such as white, or may even be transparent.

[0022] Preferably, the plunger has a single marking, in particular a single marking that is visible through the syringe during use. This can prevent the user from being confused about which marking is to be used to visually determine the volume of liquid present in the syringe, i.e. which marking of the plunger must be aligned with the marking of the syringe.

[0023] Typically, the marking of the plunger may be a printed marking, for example printed on the plunger body. Alternatively, the marking may be a connectable marking connectable to the plunger body. For example, the marking may be annular, or at least partially annular. The marking may, for example, be stuck on the plunger, or be glued on the plunger.

[0024] As a further option, the marking of the plunger may be formed of a material different from the segment of the plunger body adjacent to the marking. The material may differ, for example, in that it has a different color or general visual appearance, so that the user can visually distinguish the marking of the plunger, particularly through a transparent portion of the syringe.

[0025] Embodiments of the plunger may also include a thickened proximal segment that may function as a stopper with the syringe that prevents further insertion of the plunger into the syringe. Thus, the thickened proximal segment may determine a non-retracted position of the plunger. The thickened proximal segment may be thickened from the perspective of having a diameter that is greater than a diameter of a distal adjacent segment of the plunger. The thickened proximal segment may be disposed on an opposite side of the plunger body relative to the piston.

[0026] The distance between the piston and the marking may be less than the distance between the thickened proximal segment and the marking, in particular, at least less than half the distance between the thickened proximal segment and the marking. Alternatively, the distance between the piston and the marking may be equal to or greater than the distance between the thickened proximal segment and the marking. The positioning of the marking of the plunger may depend, for example, on the presence of a label on the syringe body that may obstruct the user's view of the syringe.

[0027] A second aspect provides a syringe barrel for a syringe assembly. It will be appreciated that the plunger according to the first aspect may be used in combination with a syringe barrel according to the second aspect, but it is envisaged that it may also be used in combination with other syringe barrels.

[0028] The syringe according to the second aspect comprises a syringe body having an axial passage therethrough, wherein the syringe body is at least partially transparent and the syringe comprises a zero mark on the syringe body, the zero mark being spaced a distance from the distal end of the syringe.

[0029] When the zero mark of the syringe is spaced a distance from the distal end of the syringe, all parts except the piston of the plunger can be used to visually determine the volume of liquid present in the syringe assembly formed by the syringe and plunger according to the first aspect, in particular, to determine that the volume is substantially zero.

[0030] When the syringe body is at least partially transparent, objects within the syringe body, such as the plunger, in particular the markings of the plunger, may be visible from the outside of the syringe body. Thus, in particular, the syringe body may be at least partially transparent relative to the markings of the plunger. Thus, transparent may be interpreted as at least partially see-through. Typically, the syringe body may consist of or include glass and / or a polymer such as polypropylene.

[0031] The zero mark can be defined as including any visible mark that indicates to the user that the volume of liquid present in the syringe is substantially zero. The zero mark can be used in combination with a mark on the plunger located inside the syringe. For example, at least a portion of the zero mark can resemble: the number zero ("0"), the word zero (in any language), for example in combination with a quantity (such as 0 mL); or any other word that indicates to the user that the volume of liquid present in the syringe is substantially zero, such as the word empty (in any language) or any equivalent wording (in any language); or any symbol that indicates to the user that the volume of liquid present in the syringe is substantially zero, such as a letter indicating the word empty or equivalent wording (for example, the letter E indicates empty); or any combination thereof.

[0032] Alternatively, the syringe may include a connecting flange connected to the skirt, in particular for forming a Luer lock connection with the needle hub. In these embodiments, the zero mark may be spaced a distance from the connecting flange, and the connecting flange may be located between the distal end of the syringe body and the zero mark. In particular, the connecting flange is located at or near the distal end of the syringe.

[0033] It will be appreciated that printing a mark too close to the connecting flange may be impractical or even impossible, as the radially extending connecting flange may obstruct the print head. Therefore, a zero mark cannot or will not be provided by previously known syringes. With the syringe according to the second aspect, it is now possible to provide a zero mark on the syringe, as the zero mark is spaced a distance from the distal end of the syringe body.

[0034] The volume of the axial passage through the syringe may be less than 0.5 mL, in particular even less than 0.3 mL, or even less than 0.2 mL. Thus, the maximum liquid capacity of the syringe may be less than 0.5 mL, in particular even less than 0.3 mL, or even less than 0.2 mL. However, it will be understood that the present invention also includes syringes with other liquid volumes, and greater than 0.5 mL, such as 1.0 mL.

[0035] In addition to or as an alternative to the zero mark, the syringe may include one or more volume markings on the syringe body as an option. If the syringe also includes a zero mark, the one or more volume markings are spaced an axial distance from the distal end of the syringe and at an axial distance from the zero mark. The volume marking may be similar to a specific one or more numbers, one or more numbers written as one or more words in any language, for example in combination with a quantity, such as 0.05 mL.

[0036] Any markings on the syringe, such as a zero mark or a volume mark, may include one or more alignment marks, wherein the marking of the plunger may be aligned with the alignment mark. The alignment mark may, for example, be a line substantially perpendicular to the axial direction, which may partially or completely surround the syringe body.

[0037] A third aspect provides a syringe assembly comprising a barrel, for example according to the first aspect, and a plunger, for example according to the second aspect.

[0038] In the assembly, the plunger is arranged to be at least partially inserted (particularly with the piston first) into the axial passage of the barrel body. The markings of the plunger are visible through the transparent portion of the barrel and are therefore visible to a user of the syringe assembly.

[0039] When there is an annular gap between the marking of the plunger and the inner wall of the syringe body, the marking will not hinder the movement of the plunger in the syringe body. In addition, if the marking contacts the inner wall, so there will be no annular gap, the marking can increase undesirable friction between the plunger and the syringe.

[0040] Alternatively, in the assembled state of the syringe assembly, the mark of the plunger may contact the inner wall of the syringe body. For example, the mark may contact the inner wall of the syringe body over the entire circumference of the mark or only over a portion thereof. In the case where the mark contacts the inner wall of the syringe body, due to the refraction of light, the mark of the plunger may visually appear to have the same diameter as the outer diameter of the syringe. This may make it easier for the user to align the mark of the plunger with the mark on the syringe.

[0041] The syringe assembly can be filled with less than 1 mL, less than 0.5 mL, in particular less than 0.2 mL or even less than 0.1 mL of liquid, in particular a liquid drug. In particular, when the liquid drug is used in the eye, the syringe can be filled with 0.1 mL or less (e.g., about 0.05 mL) of liquid drug. A syringe assembly having any of these capacities can be supplied as a prefilled syringe assembly, i.e., the filling position is different from the position where the liquid is discharged from the syringe assembly.

[0042] Embodiments of the syringe assembly may further comprise a needle hub having a needle, the needle hub being arranged to be connected to the needle hub at the distal end of the barrel. The connection may for example be a threaded connection, such as a Luer lock, or an adapted connection, such as a Luer slip, for example according to ISO 80369-7:2016 or 80369-7:2021.

[0043] The needle seat may comprise a pocket located at the proximal end of the needle seat, for example upstream of the needle in use, the pocket being arranged to accommodate at least a portion of the piston of the plunger in a non-retracted state of the plunger, and optionally also a portion of the distal end of the syringe, in particular a portion of the distal end of the syringe body.

[0044] For example, when the plunger is arranged to be inserted into the syringe body at the proximal end of the syringe body, at least a portion of the plunger's piston may extend beyond the distal end of the syringe, in particular at least when in a non-retracted state of the plunger, and optionally also in a partially (i.e. slightly) retracted state of the plunger. When the plunger's piston can at least partially extend beyond the distal end of the syringe body, all liquid present in the entire syringe body can be pushed out of the syringe using the plunger.

[0045] When the shape of at least a portion of the pocket of the needle seat is substantially negative to at least a portion of the shape of the plunger's piston, the dead volume of the syringe assembly can be reduced or even eliminated. For example, when the plunger's piston is convex or generally spherical, at least a portion of the pocket in the needle seat can be concave or hollow in shape. The pocket of the needle seat can also be shaped to accommodate a portion of the distal segment of the syringe body therein.

[0046] In general, it is understood that the dead volume of any embodiment of the syringe assembly disclosed herein can be substantially 0 mL, substantially 0.0 mL, or even substantially 0.00 mL. This substantial absence of dead volume can be achieved, for example, by the shape of the piston, the shape of the syringe barrel, and / or the shape of the needle seat. Therefore, any embodiment of the syringe assembly can also be a syringe assembly for the eye. In this field, accurate and / or precise administration of liquid drugs is particularly important because the volume of liquid drugs administered is very small (e.g., less than 0.05 mL) to prevent excessive accumulation of intraocular pressure in the patient. In addition, deviations of only 10% or less from the desired dose can be allowed. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the figure:

[0048] Figure 1A and 1B An isometric view of an embodiment of a syringe assembly is shown;

[0049] Figure 2A and 2B A front view of a syringe assembly is shown;

[0050] Figure 3A and 3B shows a cross-sectional view of a syringe assembly; and

[0051] Figure 4 for Figure 3B Detailed view of the . DETAILED DESCRIPTION

[0052] Figures 1A to 3B An embodiment of a syringe assembly 100 is shown, which includes a syringe barrel 106, a plunger 102, and a needle hub 104. Figure 1A and 1B In FIG. 1 , the syringe assembly 100 is shown in an isometric view. Figure 2A and 2B In the embodiment, the syringe assembly 100 is shown in a front view. Figure 3A and 3B In the embodiment, the syringe assembly 100 is shown in cross-section. In addition, as described in detail below, Figure 1A , 2A 3A, the plunger 102 is depicted in a non-retracted state, while in Figure 1B , 2B and 3B , the plunger 104 is depicted in a partially retracted state.

[0053] Generally, the same embodiment of the syringe assembly 100 is depicted in the figures. However, this should not be interpreted as limiting the scope of the present invention to this embodiment. Those skilled in the art will understand that other embodiments of the syringe assembly 100 are also conceivable, particularly by any combination of the options disclosed herein, particularly in conjunction with a syringe and a plunger. It should be understood that for the sake of clarity of the figures, not every component is provided with a reference numeral in each figure. The absence of a reference numeral does not mean that the component is absent.

[0054] Figure 1A and 1B 1 shows a syringe assembly 100, which includes a plunger 102, which is inserted into a syringe barrel 106, and in particular, into a hollow axial passage 109 of the syringe barrel 106. Figure 1B As shown, in a partially retracted state of the plunger 102 in the syringe 106, a liquid volume 101 is available, which can be filled with a liquid (e.g., a liquid drug, particularly a liquid drug for use in the eye). The plunger 102 includes a piston 118 at the distal end of the plunger, and the piston 118 forms a substantially liquid seal with the inner wall of the syringe when in use.

[0055] For example, in Figure 1A and 1B As can be seen in FIG. 1 , the marking 108 of the plunger 102 is visible from the outside through the syringe 106. Figure 1A In the embodiment of the present invention, the user can visually determine that the marking 108 on the plunger 102 is aligned with the optional zero mark 110 on the syringe. Figure 1B , the user can visually determine that the marking 108 of the plunger 102 is aligned with the volume marking 111, which in this case indicates that the available liquid volume 101 is approximately 0.10 mL.

[0056] exist Figure 1A , the plunger 102 is shown in a non-retracted state, in which the thickened proximal section 116 of the plunger 102 may abut the syringe 105. Additionally or alternatively, the non-retracted state, i.e. the state when the plunger is inserted furthest into the syringe, may be determined by the shape of the needle seat, wherein the needle seat forms a stop for the plunger, in particular a stop for a piston of the plunger.

[0057] In use, the non-retracted state may correspond to the state of the syringe assembly 100 when there is substantially no liquid in the syringe. The plunger may be moved to the retracted state by axially moving the plunger in the syringe body, for example Figure 1B The axial direction is Figure 1ABy retracting the plunger 102 relative to the barrel 106, liquid can be drawn into the barrel 106, in particular into the liquid volume 101. By pushing the plunger 102 further into the barrel 106, the liquid in the liquid volume 101 can be discharged from the barrel 106.

[0058] As shown, embodiments of the syringe 106 may include a plurality of markings 111, including an optional zero marking 110. The markings 111 may be: numbers, such as .00, .05, .10, .15, .20; quantity indications (e.g., mL) used with the numbers; and one or more lines that may or may not be read with one of the numbers. For example, a long line is provided for each 0.05 mL step, and a short line is provided for each 0.01 step between the 0.05 mL steps. In other embodiments, other step sizes may be used, such as 0.002 mL or 0.001 mL.

[0059] When the barrel 106 includes a plurality of markings, preferably at least the portion of the barrel 105 between the plurality of markings is at least partially transparent so that the user can visually determine when the markings 108 of the plunger 102 are aligned with the markings of the barrel. Figure 2B In the embodiment of the present invention, the user can visually determine that the liquid volume 101 totals approximately 0.065 mL. It will be understood that embodiments of the syringe 106 are also contemplated to include a single marking that can indicate a specific volume, such as 0.05 mL, or a single marking set that together indicate a specific volume, such as 0.05 mL.

[0060] exist Figure 2A , a distance x1 is shown, which is the distance between the distal end face 160 of the syringe 106 and the farthest mark, which is the zero mark 110 in this specific embodiment.

[0061] At the same time, Figure 2A , the distance x2 is indicated in the figure, which is the distance between the connecting flange 120 of the syringe 106 and the farthest mark. It may be preferred to minimize the distance x2. However, the minimum value of the distance x2 can be determined, for example, by a process (e.g., a printing process) of applying the farthest mark to the syringe 106. It may be preferred not to print or provide any marking on the outside of the skirt 122, because the marking of the plunger may be difficult to align with such a marking due to the radial distance between the skirt 122 and the plunger.

[0062] Figure 3A and 3BThe syringe assembly 100 is shown in cross-section, and therefore it will be appreciated that the markings on the syringe 106 are not visible in these figures. Figure 3B , a distance y1 is shown, which is the distance between the outer distal end point 162 of the plunger 103 and the marking 108 of the plunger 103. Alternatively, the distance y1 can be less than the distance y2 between the marking 108 of the plunger 102 and the thickened proximal section 116. The distance y1 can even be less than 50% of the distance y2, or even less than 25% of the distance y2. However, other embodiments are envisioned where the distance y1 is greater than the distance y2, for example due to the presence of a printed or glued label on the syringe.

[0063] Additionally, or alternatively, the distance y1 may be less than 50%, or even 25%, of the axial length y3 of the axial passage of the barrel 106. Thus, when the plunger is in the retracted state, the marking 108 may be prevented from moving out of the barrel 106. If the plunger's marking 108 is outside the barrel 106, the marking 108 may no longer be useful for a user to visually determine the volume of the liquid 101 in the barrel.

[0064] exist Figure 3B Also shown in FIG. 1 is a thickness t, which is similar to the thickness of the marking 108 of the plunger 102. The thickness t may be less than 20% of the distance y1, less than 10% of the distance y1, or even less than 5% of the distance y1. The thickness t may generally correspond to the thickness of the marking of the syringe (e.g., to the line as the marking of the syringe), or may have a smaller thickness than the marking of the syringe. For example, as Figure 2A As can be seen, this can allow the markings 108 of the plunger 102 to appear hidden behind the markings 110 of the barrel, which in turn can help the user to properly align the markings.

[0065] Figure 4 Shows Figure 3B Detailed view of the syringe assembly 100 in FIG. Figure 4 As can be seen, the needle hub 104 can include a connection flange 141 that can be screwed into the skirt 122 of the barrel 106, for example according to the Luer lock standard. In general, the skirt 122 can be generally axially oriented and the connection flange 120 can be generally radially oriented.

[0066] exist Figure 4 , the oblique lines show an embodiment of the distal segment 119 of the piston 118 of the plunger 102. Figure 4 FIG. 1 shows an embodiment of a curved distal segment 119 of a piston 118. Generally, the distal segment of the piston may have a flat end surface or a curved end surface. In particular, the curved end surface may be a convex end surface, for example, Figure 4The generally dome-shaped end surface shown. Such a raised end surface can prevent liquid from being trapped in the syringe 100, particularly in conjunction with the needle hub 104, as explained below. Additionally or alternatively, the raised end surface can prevent air from being trapped between the end surface and the needle hub, such as when the plunger is inserted into the syringe barrel and fully depressed to a non-retracted state.

[0067] Generally, for syringe assemblies, it may be preferred to reduce the dead volume of the syringe, or even eliminate the dead volume. The dead volume is defined as the volume of liquid that is retained in the syringe assembly even when the plunger is fully inserted into the syringe barrel (i.e., in a non-retracted state, such as shown in Figure 34). In particular, when syringe assemblies are used in conjunction with expensive liquids (e.g., liquid drugs, particularly liquid drugs for the eye), even if the dead volume is reduced by a small amount, it may be economically beneficial because it reduces the volume of liquid drugs that must be discarded with the syringe assembly after the remainder of the liquid drug has been discharged from the syringe assembly. Additionally or alternatively, reducing or eliminating the dead volume can improve the accuracy and / or precision with which liquids can be discharged from the syringe assembly.

[0068] exist Figure 4 In the illustrated embodiment, in order to reduce or even eliminate dead volume, the needle hub 104 includes a pocket 144 located at the proximal end of the needle hub. The pocket 144 is configured to accommodate at least a portion of the piston 118, in particular, the distal segment 119 of the piston 118 in the non-retracted state of the plunger 102. Figure 4 As shown, the negative shape of at least a portion of the shape of the pocket 144 preferably substantially corresponds to the shape of the distal segment 119 of the piston. In order to allow the piston 118 to be at least partially inserted into the pocket 114 of the needle hub 104, at least a portion of the piston 118 can extend beyond the distal end of the syringe 106 when the plunger is in the non-retracted state. This state can be seen, for example, Figure 3A The non-retracted state may correspond to a fully inserted state of the plunger. When positioning the indicia 108 on the plunger, due consideration must be given to how far the piston 118 may extend from the distal end of the barrel 106 in the non-retracted state.

[0069] The sealing segment 146 of the piston 118 is arranged to form a fluid seal with the inner wall 140 of the hollow passage through the barrel 105 when in use. The sealing segment 146 can be located adjacent to the distal segment 119 of the piston 118 and between the distal segment 119 and the marker 108.

[0070] As Figure 4In the illustrated option, there may be an annular space 142 between the marking 108 of the plunger and the inner wall 140 of the syringe body 105. Thus, in use, when the plunger moves in the syringe, the marking 108 does not hinder the movement. In an alternative embodiment, the marking 108 may contact the inner wall 140 of the syringe 105.

[0071] In the above description, it is understood that when an element is mentioned to be connected to another element, the element is either directly connected to the other element, or there may be intermediate elements. In addition, it is understood that the values ​​given in the above description are given by way of example, and other values ​​may be possible and / or may be expanded to other values.

[0072] It should be noted that the accompanying drawings are only schematic representations of embodiments given by way of non-limiting examples. For the purpose of clarity and concise description, features are described herein as part of the same or separate embodiments, however, it should be understood that the scope of the present invention may include embodiments having a combination of all or part of the described features.

[0073] The term "comprising" does not exclude the presence of other features or steps. Furthermore, the words "a" and "an" should not be understood as being limited to "one", but are used to mean "at least one", and do not exclude a plurality.

Claims

1. A plunger (102) for a syringe assembly (100), the plunger comprising: - an axially extending plunger body (103) having a piston (118) at or near a distal end of the plunger; - a visible marking (108) connected to or arranged on the plunger body (103); The visible mark (108) is spaced a distance (y1) from the piston.

2. Plunger according to claim 1, wherein the piston (118) has a curved end section (119), in particular at least partially dome-shaped.

3. The plunger according to any one of claims 1 to 2, wherein the plunger comprises a single marking (108).

4. The plunger according to any one of claims 1 to 3, wherein the marking is a printed marking.

5. The plunger according to any one of claims 1 to 3, wherein the marking is a connectable marking connectable to the plunger body.

6. A plunger according to any one of claims 1 to 5, wherein the plunger also includes a thickened proximal segment (116), and wherein the distance (y1) between the piston (118) and the mark (108) is smaller than the distance (y2) between the thickened proximal segment and the mark, in particular at least smaller than half of the distance (y2) between the thickened proximal segment and the mark.

7. A syringe assembly (100), comprising: - a syringe (106) comprising a syringe body (105) having an axial passage through the syringe (106), wherein the syringe body is at least partially transparent and the syringe comprises at least one marking; - A plunger (102) according to any one of claims 1 to 6, arranged to be at least partially inserted into the axial passage of the syringe body; wherein the indicia (108) of the plunger (102) is visible through at least a portion of the syringe body.

8. The syringe assembly of claim 7, wherein in an assembled state, an annular gap (142) exists between the marking (108) of the plunger and the inner wall (140) of the barrel.

9. The syringe assembly of claim 7, wherein in an assembled state, the marking (108) of the plunger is in contact with an inner wall (140) of the barrel body.

10. A syringe assembly according to any one of claims 7 to 9, wherein the syringe assembly further comprises a needle hub (104) having a needle (114), the needle hub (104) being arranged to be connected to the syringe at the distal end of the syringe, in particular connected to the syringe by a threaded connection or an adapter connection.

11. The syringe assembly according to any one of claims 7 to 10, wherein the barrel is filled with less than 1 mL of liquid, in particular about 0.05 mL of liquid medicine, in particular liquid medicine for use in the eye.

12. A syringe assembly according to any one of claims 7 to 11, wherein the plunger is arranged to be inserted into the syringe body at the proximal end of the syringe body, and in the non-retracted state of the plunger, at least a portion of the piston (118) of the plunger is capable of extending beyond the distal end of the syringe.

13. A syringe assembly according to claim 12, within the scope of claim 10, wherein the needle seat includes a bag portion (144) located at the proximal end of the needle seat, and the bag portion is arranged to accommodate at least a portion of the piston of the plunger when the plunger is in a non-retracted state.

14. The syringe assembly of claim 13, wherein the negative of the shape of at least a portion of the pocket (144) of the needle hub substantially corresponds to at least a portion of the shape of the piston of the plunger.

15. The syringe assembly according to any one of claims 7 to 14, wherein when the plunger is fully inserted into the syringe and the dead volume of the syringe assembly is substantially 0 mL, the mark (108) of the plunger is aligned with at least one mark of the syringe, in particular with the zero mark of the syringe.

16. A syringe assembly according to any one of claims 7 to 15, wherein when the available volume of liquid in the syringe is approximately 0.05 mL or less, the mark (108) of the plunger is aligned with at least one mark of the piston on the syringe away from the plunger.

17. A syringe assembly according to any one of claims 7 to 16, wherein the syringe comprises a connecting flange (120) having a skirt (122) at the distal end of the syringe, in particular for forming a Luer lock connection with a needle hub, and wherein when the plunger is fully inserted into the syringe, the marking (108) of the plunger is not aligned with the skirt (122).

18. The syringe assembly of any one of claims 7 to 17, wherein the entire barrel is transparent except for at least one indicia.

19. A syringe (106) for a syringe assembly (100), the syringe comprising a syringe body (105) having an axial passage through the syringe (106), wherein: - the barrel body is at least partially transparent; and - The syringe comprises a zero mark (110) on the syringe body, the zero mark being spaced a distance (x1) from the distal end (D) of the syringe body.

20. The syringe of claim 19, wherein: The syringe also includes: - a connecting flange (120) having a skirt (122), in particular for forming a Luer lock connection with a needle hub; The zero mark (110) is spaced a distance (x2) from the connecting flange, and the connecting flange is located between the distal end (D) of the syringe body and the zero mark.

21. The syringe according to claim 19 or 20, wherein the volume of the axial passage through the syringe is less than 0.5 mL, in particular even less than 0.3 mL, in particular about 0.2 mL.

22. The syringe according to any one of claims 19 to 21, wherein the syringe further comprises one or more volume markings (111) on the syringe body at an axial distance from the zero marking.

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