Dosage container

Abstract

The syringe 1 has a longitudinal section 5 in which a plunger 10 is movably guided, the plunger 10 closing the syringe barrel 5 at one end and being movable by a plunger rod 9. The other distal end of the syringe barrel 5 is provided with a connection 4 for attaching an injection needle 11. The plunger 10 is movable beyond the distal end of the connection 4 to reduce dead volume.

Description

[Technical Field]

[0001] The present invention relates to a dosage container, in particular a syringe, having a longitudinal section in which a plunger is movably guided, which closes the dosage container at one end and is movable by a plunger rod, which has at its other end a connection for attaching an injection needle and which can be a pre-filled dosage container, as is common in syringes, or a container that can be filled before administration. [Background technology]

[0002] In general, with the ongoing development of injectable active ingredients that are sensitive, highly effective, expensive or of limited availability, even at low doses in the microliter range, there is a need for dosage containers, in particular syringes, which, on the one hand, allow the administration of small amounts accurately even by manual injection, and, on the other hand, minimize the amount of unused active ingredient remaining in the dosage container and the connected injection needle, which is no longer in use and has to be discarded together with the container.

[0003] Disposable syringes are known for small injections, e.g., with an internal diameter as small as 4.5 mm and finely graduated volumes, e.g., for injecting 1 ml. To reduce dead volume, a conventional technique involves providing syringes with a so-called push-out plug, which protrudes into the luer cone, i.e., the syringe's connection, to push the liquid therein and discharge it through the needle. However, a cannula must be attached for injection, and dead volume at the cannula base and needle always remains. Further optimization of dead volume is difficult when using the globally adopted luer standard. However, deviation from this standard results in the syringe losing compatibility with available cannulas and therefore versatility.

[0004] Alternatively, integrated needle syringes do not require a needle attachment; the needle is integrally formed with the syringe, allowing for a relatively small dead volume, but the needle cannot be replaced. Furthermore, the thinnest needles currently available are technically very difficult to connect to syringes. To prevent damage to the needle tip, drug adhesion, and non-sterile conditions, the needle must be replaced after drawing up the drug. In many cases, aspiration cannulas are also not suitable for injection.

[0005] Prefilled syringe systems can avoid most of the aforementioned problems. However, to ensure accurate dosing, the syringe diameter must be as small as possible, the diameter must be constant throughout the syringe length, and the syringe must not exceed a manageable length to accommodate the required volume. Currently, glass syringes typically have a minimum fill volume of 0.5 ml, a minimum glass tubing inner diameter of 4.5 mm, and are available with Luer or Luer lock connections or integrated needles. Plastic syringes can be manufactured with greater precision in terms of syringe inner diameter and syringe tip contour, but glass syringes have manufacturing disadvantages compared to plastic syringes in terms of dead volume and dosing accuracy. However, due to established industry standards for dimensions, plastic syringes also correspond to the typical dimensions of glass syringes.

[0006] In the case of pre-filled syringes with an integral needle, the tip of the needle must be tightly and sterilely sealed, usually by a needle cap, which can easily break or become damaged, rendering the entire syringe and its contents unusable, especially for very thin needles such as those required for intraocular injections.

[0007] Furthermore, some glass or plastic cartridges are equipped with motor-driven feeds for precise control, allowing for very accurate and reproducible dosing. However, emptying the cartridge is rather difficult, especially if it is closed with a septum that can be pierced several times by the needle of the syringe being filled. Summary of the Invention [Problem to be solved by the invention]

[0008] Against this background, the present invention is based on the problem of designing a dosing container, in particular a syringe of the type mentioned above, so as to overcome the problems mentioned above, in particular so as to reduce the dead volume during injection. [Means for solving the problem]

[0009] The above problem is solved according to the invention by a dosage container having the features set forth in claim 1. Advantageous embodiments of the invention emerge from the dependent claims, the following description and the drawings.

[0010] The dosage container according to the invention, in particular the syringe according to the invention, has a longitudinal section in which a plunger is movably guided, the plunger closing the dosage container at one end and being movable by a plunger rod. The dosage container has a connection for attaching an injection needle to the other end of the dosage container. According to the invention, the plunger is movable beyond the distal end of the connection in order to reduce dead volumes. It should be noted here that the terms "distal" and "proximal" in this specification refer to the user of the dosage container and not to the patient to whom the contents of the dosage container are to be administered.

[0011] The basic idea of ​​the solution according to the invention is to design a dosage container having a connection part for attaching an injection needle and a plunger movably guided therein and movable beyond the distal end of the connection part, so that the dead volume present in the area of ​​the corresponding connection part with the injection needle is at least partially filled by the plunger and the drug in the dosage container is administered as completely as possible through the injection needle.

[0012] The administration container of the present invention is typically a syringe, but may also be another container for storing and administering medicines or other medicaments. The cross-sectional shape of the longitudinal section along which the plunger is movably guided is preferably circular, but not necessarily circular; it can also be oval, triangular, or polygonal, preferably with rounded corners. The plunger does not necessarily have the same cross-sectional shape as the longitudinal section, but at least has a shape that matches it, and is movable within the longitudinal section but is configured to seal the longitudinal section, thereby forming a container, particularly a syringe, with one end closed by the plunger and the other end having a connecting section for attaching a mating part with an injection needle or another line-compatible connecting section. After passing through the distal end of the connecting section on the container side, the plunger can penetrate into the mating part with an injection needle or another line-compatible connecting section, at least partially eliminating any dead volume present therein. Advantageously, the plunger is configured to completely eliminate the dead volume in the mating part up to the needle.

[0013] This is advantageously achieved by designing the longitudinal section, along which the plunger is movably guided, so that the inner cross section of the longitudinal section continues into or is smaller than the inner cross section of the connecting section. Preferably, the inner wall of the longitudinal section is flush with the inner wall of the connecting section, preferably transitioning without a step. In the case of plastic containers, particularly plastic syringes produced by injection molding, the inner wall always has a certain degree of taper, which is necessary for the molding of the workpiece. This taper is negligibly small as far as the constant cross section, which is essential for the present invention, is concerned.

[0014] Designing the connection, in particular the syringe connection, as a luer or luer lock connection is particularly advantageous, since, as mentioned at the beginning, this ensures a high degree of compatibility of the administration container according to the invention with existing cannula and line connections. When using a luer or luer lock connection, it is expedient to design the plunger and the longitudinal part of the administration container surrounding it with a circular cross section, with the inner diameter of the cylindrical part being smaller than the outer diameter of the (male) luer cone, so that the plunger can completely eliminate as far as possible the dead volume formed in the (female) mating connection part of the luer cone.

[0015] If the inner wall of the longitudinal section of the dosage container merges into the inner wall of the luer cone of the luer connection or luer lock connection, a displacement volume arises within the attached luer compatible connection part or luer lock compatible connection part.

[0016] According to an advantageous development of the invention, this displacement volume can be further increased if at least a portion of the distal end of the plunger is formed with soft elasticity at least in a direction transverse to the direction of movement, so that the distal end of the plunger expands radially after moving beyond the distal end of the connecting part. With such a design, the volume of the mating part can be substantially filled up to the needle or the narrow recess leading to the needle. Then, essentially only the internal volume of the needle and the channel (flow path) in the mating part leading to the needle remains as dead volume.

[0017] In the present invention, soft elasticity can be understood to mean a soft or flexible material (elastomer) with an elastic modulus of less than 700 MPa. On the other hand, hard elasticity in the present invention means rigid and semi-rigid materials as defined by the ISO 80369 standard. Rigid materials have a flexural or tensile modulus of elasticity greater than 3.433 MPa, and semi-rigid materials have a flexural or tensile modulus of elasticity between 700 and 3.433 MPa.

[0018] Apart from the taper required to remove the syringe from the mould, it is advantageous to design the longitudinal section along which the plunger is movable with a constant internal cross section that continues into the connection. Preferably, this longitudinal section is designed cylindrically and has a circular cross section.

[0019] Optionally, when the injection needle is attached to the connection part, a dead space having an axial dead space length and a radial dead space inner cross section may extend distally from the distal end of the connection part, and the plunger can move into this dead space. This dead space occurs due to the standardized design of the corresponding connection part of an injection needle having a female luer connection or luer lock connection when it is attached to a male luer connection or male luer lock connector of a dosage container.

[0020] Optionally, the plunger may have an axial length greater than the axial dead volume length, which has the advantage that the proximal portion of the plunger remains sealed within the connection, preventing backflow into the longitudinal portion.

[0021] Optionally, the plunger rod may be long enough so that the plunger abuts the corresponding connecting portion of the injection needle in the dead space in the axial direction, thereby plastically and / or elastically compressing the plunger in the dead space and radially expanding within the dead space to a cross-section within the dead space. In this case, the dead space is almost completely filled with the plunger by manually pushing the plunger, and the remaining dead volume is essentially the internal volume of the needle and the internal volume of the channel leading to the needle in the corresponding connecting portion. By pushing the plunger in the axial direction, the proximal rear edge of the plunger can be pushed beyond the distal end of the connecting portion, so that the proximal rear edge of the plunger expands radially within the dead space and engages with the axial end face of the connecting portion located behind it.

[0022] Optionally, the inner cross-section of the dead space, at least at the proximal end of the dead space, may be larger than the inner cross-section of the longitudinal section continuing to the connecting portion. In this case, at least a portion of the plunger, for example, the outer sealing lip of the plunger, is designed to be flexible and elastic at least in a direction intersecting the direction of movement of the plunger so as to radially expand into the inner cross-section of the dead space within the dead space. The dead space is almost completely filled by the plunger, which is radially compressed at the inner cross-section of the longitudinal section and elastically expands radially within the dead space, so that essentially only the internal volume of the needle and the internal volume of the channel leading to the needle in the corresponding connecting portion remain as dead volumes. The axial length of the plunger may be approximately equivalent to the length of the dead space. This allows the proximal rear edge of the plunger to be pushed beyond the distal end of the connecting portion, where it radially expands within the dead space and engages with the axial end face of the connecting portion located behind it.

[0023] In order to prevent the plunger from exerting excessive axial force on the mating part in the depressed position of the plunger, it is advantageous to limit the axial pushing path of the plunger in the distal direction, preferably in such a way that the soft elastic part of the plunger penetrates into the mating part and thereby almost completely fills the dead volume present therein, but does not exert an unacceptably large axial force in the distal direction that could jeopardize the connection between the connection part and the mating part.

[0024] Advantageously, such a limitation can be effected by a resting mechanism, preferably formed between the plunger and the inner wall of the dosage container or between the plunger rod and the dosage container. Instead of a resting position, a stop can also be provided, which limits the distal pushing path of the plunger.

[0025] In addition to limiting the pushing path, it may be advantageous, for example, to provide one or more resting mechanisms with resting positions in which, for example, the plunger closes the dosage container but does not yet move until the container contents have been metered and dispensed, and / or the distal end of the plunger has reached the distal end of the luer connection.

[0026] It is particularly advantageous if the dosage container, when configured as a syringe, is provided at its proximal end with a finger rest that forms a stop for a thumb rest arranged at the end of the plunger rod, which makes manual dosage particularly easy to handle and makes incorrect operation virtually impossible.

[0027] The design according to the invention is particularly suitable for, but not limited to, small dose syringes, for example 0.3 ml, and is particularly suitable as a pre-filled dosage container, in which the luer or luer lock connection is tightly closed by a cap, which is removed immediately before use and replaced by an injection needle having a luer or luer lock compatible connection.

[0028] It is particularly advantageous if the cap closing the dosage container is designed to simultaneously prevent the plunger from being inserted, for example by covering the thumb rest, or if a separate cap is provided which is arranged proximally to the dosage container and is designed to prevent actuation of the plunger rod, in particular the thumb rest of the plunger rod, which cap must be removed before use.

[0029] Basically, the embodiment according to the present invention can be implemented in various suitable dosage containers, and is particularly advantageous in syringes, regardless of whether the syringe body is made of glass or plastic.However, the present invention is particularly advantageous when implemented using a syringe body made of plastic.The embodiment according to the present invention is advantageously used in pre-filled syringes. [Brief explanation of the drawings]

[0030] [Figure 1] FIG. 1 is a longitudinal cross-sectional view of a syringe having a luer lock connection. [Figure 2] FIG. 1 is a longitudinal cross-sectional view of a syringe with a luer connection and a corresponding connection portion with an attached needle. [Figure 3] FIG. 3 illustrates an alternative embodiment to that shown in FIG. 2. [Figure 4] 1 is an enlarged vertical cross section of a luer lock connection part on the container side having an inner cone. [Figure 5] 1 is a schematic diagram of a syringe with the plunger in five different positions. [Figure 6] FIG. 1 shows a syringe with an attached needle and proximal protective cap. [Figure 7] FIG. 7 shows the syringe according to FIG. 6 fitted with a distal protective cap. DETAILED DESCRIPTION OF THE INVENTION

[0031] The invention will now be explained in more detail with reference to embodiments shown in the drawings.

[0032] The syringe 1 shown in FIG. 1 is a prefilled syringe having a distal luer lock connection, and the distal end of the syringe 1, particularly the luer cone 4, is sealed by a protective cap 3 attached to the distal luer lock connection. The syringe has a syringe barrel 5, the cylindrical inner wall 6 of which continues to the luer cone 4, forming a continuous cylindrical inner wall throughout the syringe 1. A finger rest 7 is integrally formed at the proximal end of the syringe barrel 5. The finger rest 7, together with a thumb rest 8 at the proximal end of a plunger rod 9, is provided for manually administering the medication in the syringe barrel. A plunger 10 is located at the tip of the plunger rod 9. The plunger 10 is axially movably disposed within the syringe barrel 5 and seals the syringe barrel on the proximal side. The syringe barrel 5 and plunger rod 9 are made of a hard elastic plastic, while the plunger 10 is made of a soft elastic plastic, as is the inside of the protective cap 3 that seals the luer cone 4. The elasticity of the material causes the plunger 10 to expand radially as it passes over the distal end of the luer cone 4 to fill the dead volume created within the luer cone's female mating connection.

[0033] In Figure 1, the axial dimensions of the plunger rod 9 with the plunger 10 and the syringe barrel 5 with the luer cone 4 are not drawn to scale, but rather, as in the case of the syringe shown in Figure 2, the plunger 10 can be pushed distally by the plunger rod 9 after the protective cap 3 is removed, allowing the plunger 10 to protrude distally of the luer cone 4 to fill the dead space that would be formed in this area if a mating connector were attached. In the syringe shown in Figure 2, the luer cone 4 is integrally formed at the tip of the syringe barrel 5, and an injection needle 11 is disposed on the luer cone 4 and attached to the luer cone 4 by its mating connector 12. In the syringe, the plunger rod 9 with the plunger 10 attached to its distal end is pushed beyond the distal end of the luer cone 4 and into the mating connector 12, or more specifically, to the step where the mating connector 12 tapers to accommodate a needle 13. In this position, the contents of the syringe have been completely expelled, with only the remaining small hollow space formed by the needle 13 still filled.

[0034] In the embodiment shown in FIG. 3, the mating portion 12 is tapered in the area 14 that protrudes beyond the luer cone 4, allowing the soft elastic plunger 10 to substantially completely fill the dead volume therein.

[0035] 4 shows a syringe-side embodiment of the luer lock connection 2, in which the cylindrical inner wall 6 in the region of the luer cone 4 transitions into a conically tapering region 14 in the distal direction. In this region 14, the soft-elastic plunger 10 is radially compressed by forward movement, and the pushing resistance increases, so that the user perceives that the plunger 10 only needs to move a small further distance in order to reach the end of the luer cone 4 and eliminate the dead volume in the counter-connection part 12. At the same time, the radial compression allows the plunger 10 to expand radially well beyond the luer cone 4.

[0036] Operation of such a syringe 1 can be simplified by an appropriate resting mechanism, as shown in Figure 5. The syringe shown in Figure 5a has a circumferential resting protrusion 15 on the cylindrical inner wall 6 near the proximal end, which is arranged so that the plunger rod 9 with the plunger 10 cannot be completely removed from the syringe but can only be withdrawn to a position where the maximum possible volume is drawn up. In Figure 5b, in addition to the circumferential resting protrusion 15, the plunger 10 is provided with a cooperating circumferential resting protrusion 16 which indicates a specific position of the plunger 10, e.g., a predetermined filling volume.

[0037] The rest protrusions 15 and 16 are advantageously designed to allow passage by elastic deformation after overcoming resistance. In the syringe shown in Figure 5c, such a rest position is provided when the plunger 10 is approximately half-retracted. The rest mechanism shown in Figure 5d shows the position where the plunger 10 has reached the distal end of the luer cone 4, which creates a resistance that, once overcome, tells the practitioner that only the dead volume in the mating part 12 needs to be further filled.

[0038] Finally, Figure 5e shows an arrangement in which the circumferential rest projections 15 and 16 can be radially expanded to form not only a rest mechanism but also a stopper. In the position shown in Figure 5e, the plunger 10 has reached the end of its distal travel within the mating part 12, past the luer cone 4, so it is advantageous to provide a stopper instead of a rest mechanism. The plunger 10 then comes to a stop against a step in the mating part 12. The stopper effectively prevents the plunger 10 from exerting an unacceptably large axial force on the mating part 12, which would prevent the mating part from fitting securely to the luer cone 4.

[0039] In the syringe shown in FIG. 6 , the plunger 10 is in its distal position, positioned within the mating portion 12, and the stopper is formed by the thumb rest 8, which abuts against the finger rest 7 attached as a separate part. This shows that, depending on the design of the plunger-syringe barrel configuration, the stopper does not necessarily have to be provided between the plunger rod and the syringe barrel, but can be formed, for example, by a combination of the finger rest 7 and the thumb rest 8 at the end of the plunger rod 9. The finger rest 7 is further extended proximally by a cylindrical projection 17, which is provided for mounting a proximal protective cap 18 that protects the proximal end of the plunger rod 9 with the thumb rest 8 from being activated. This proximal protective cap 8 is particularly advantageous in the case of a pre-filled syringe, as shown in FIG. 7, in which the plunger rod 9 is withdrawn proximally, forming a volume 19 tightly sealed by the protective cap 3 between the cylindrical inner wall 6, the plunger 10 and the end of the luer cone 4.

[0040] As is clear from the above description, the individual features of the present invention can be used to advantage both alone and in combination. [Explanation of symbols]

[0041] 1 syringe 2 Luer lock connection 3 Protective cap 4. Lure Cone 5 Syringe barrel 6 Cylindrical inner wall 7 Finger rest 8 Thumb rest 9 Plunger Rod 10 Plunger 11 Syringe needle 12 Mating connection parts 13 needles 14 Tapered area 15 Resting protrusion 16 Resting protrusion 17 Cylindrical protrusion 18 Proximal Protective Cap 19 Volume

Claims

1. 1. A dosage container, in particular a syringe (1), having a longitudinal section (5) that closes the dosage container at one end and in which a movable plunger (10) is movably guided by a plunger rod (9), and a connection part (4) for attaching an injection needle (11) to the other end of the dosage container, characterized in that the plunger (10) can be moved beyond the distal end of the connection part (4) in order to reduce dead volume.

2. 2. A dosage container according to claim 1, characterized in that the connection is designed as a luer connection (4) or a luer lock connection (2).

3. 3. A dosage container as described in claim 1 or 2, characterized in that at least a portion of the distal end of the plunger (10) is designed to have soft elasticity at least in a direction perpendicular to the movement direction of the plunger (10) so as to expand radially after the distal end of the plunger moves beyond the distal end of the connection portion (4).

4. 10. A dosing container according to any one of the preceding claims, characterized in that the longitudinal portion (5) has a constant, in particular cylindrical, inner cross section (6) which continues up to the connection part (4).

5. 10. The dosage container according to claim 9, wherein when the injection needle (11) is attached to the connection part (4), a dead space having an axial dead space length and a radial dead space inner cross section extends distally from the distal end of the connection part (4), and the plunger (10) is movable into the dead space.

6. 6. A dosing container according to claim 5, characterized in that the plunger (10) has an axial length that is greater than the axial dead space length.

7. 7. The dosage container according to claim 5, wherein the plunger rod (9) is sufficiently long so that the plunger (10) abuts axially against the corresponding connecting part (12) of the injection needle (11) in the dead space, whereby the plunger (10) is compressed axially in the dead space and expands radially in the dead space to the cross section of the dead space.

8. A dosage container as described in any one of claims 5 to 7, characterized in that the inner cross-section of the dead space is larger than the inner cross-section of the longitudinal portion (5) continuing distally to the connection portion (4), and at least a portion of the plunger (10) is designed to have soft elasticity at least in a direction perpendicular to the movement direction of the plunger so as to expand radially within the dead space to the inner cross-section of the dead space.

9. 10. A dosing container according to any one of the preceding claims, characterized in that the axial pushing path of the plunger (10) is limited in the distal direction.

10. 10. A dosage container according to any one of the preceding claims, characterized in that at least one resting mechanism (15, 16) is provided between the plunger (10) and the inner wall (11) of the dosage container or between the plunger rod (9) and the dosage container.

11. 11. The dosage container according to claim 10, characterized in that the resting mechanism (15, 16) is provided with a resting position in which the plunger (10) reaches the distal end of the luer connection (4) or luer lock connection (2).

12. 12. A dosage container as claimed in claim 10 or 11, characterized in that the resting mechanism (15, 16) has a stop position in which the plunger (10) closes the dosage container but has not yet moved to the extent of metering and dispensing the contents of the container.

13. A dosage container according to any one of the preceding claims, characterized in that a stopper (15) is provided for the plunger (10) or the plunger rod (9), the stopper (15) limiting the path of movement of the plunger (10) in the distal direction.

14. 14. The dosage container of claim 13, wherein the stopper (15) is arranged to limit the movement path of the plunger (10) before or until it reaches a step in the cannula base (12) of the cannula (11) attached to the luer connection (4) or luer lock connection (2).

15. A dosage container according to any one of the preceding claims, characterized in that the proximal end of the dosage container is provided with a finger rest (7) which forms a stop for a thumb rest (8) arranged at the end of the plunger rod (9).

16. 10. A dosing container according to any one of the preceding claims, characterized in that the dosing container is pre-filled and is provided with a cap (3) that closes the luer connection (4) or luer lock connection (2).

17. 10. A dosage container according to any one of the preceding claims, characterized in that it is provided with a protective cap (18) attached to the proximal side of the dosage container to prevent actuation of the thumb rest (8) of the plunger rod (9).

18. 10. A dosage container according to any one of the preceding claims, characterized in that the dosage container is made of plastic and formed as a plastic injection moulded part.

19. 10. A dosage container according to any one of the preceding claims, characterized in that the inner diameter of the syringe barrel (5) is smaller than the outer diameter of the luer cone (4).

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