CONTAINER PLUG FOR HIGH-PITCH APPLICATIONS

Description

BACKGROUND

[0001] Some automated blood analyzers mix different reagents with blood samples or other fluids under test as part of their analysis protocols. High throughput analyzers generally store a relatively large amount of the various reagents in containers that are repeatedly accessed by needle type aspirator probes to obtain the needed amounts of reagents for testing. The reagent containers may have openings that are enclosed by an elastomeric stopper. The elastomeric stopper can be pierced by a needle-type aspirator probe and substantially recloses itself to seal the container when the aspirator probe is removed.

[0002] In currently available high-throughput automated analyzers, a reagent container stopper may be subject to as many as 750 piercings by aspirator probes before the reagent container's contents are exhausted. The large number of piercings can cause fragmentation and coring of the container stopper. Such fragmenting and coring of the container stopper can result in inadequate sealing of the reagent container and / or contamination of the reagents which can and lead to inaccurate analysis results and other system level reliability problems, for example.

[0003] US 5 817 082 A describes a disposable closure assembly / container combination for delivering medial fluid to a patient by needleless access means. The closure assembly comprises an elastomeric stopper for sealing the container at its open end and a spike access means equipped with a luer lock.

[0004] EP 0 564 037 A1 describes an abrasion-resistant stopper for a medical vial for containing a fluid therein comprising a stopper body of an elastomeric material having a head portion and a fluid contactable leg portion, the leg portion being adapted to be inserted into the medical vial for hermetically sealing the fluid therein and the head portion comprising a top surface to receive a coating thereon, the top surface being coated with an abrasion-resistant coating to prevent generation of particles upon piercing of the stopper by a spike or a hypodermic needle. Preferably the coating covers at least the centre, pierceable portion of the top surface and is advantageously polytetrafluoroethylene.

[0005] WO 94 / 15850 A1 describes a closure for sealing the open end of a container and usable with a blunt entry device, wherein the sealing includes a resilient body having a central diaphragm portion, peripheral flange portion, and a hollow plug portion. The plug portion depends from the circumference juncture of the flange and diaphragm portions and sealingly engages the interior of the open end of the container. The diaphragm portion is configured for minimal entry force by the blunt entry device. A metal ferrule which secures the stopper to the container has an annular skirt portion for engagement with the exterior of the container.SUMMARY

[0006] The claimed invention is defined by a pierceable stopped according to appended claim 1.

[0007] The present disclosure includes a resealing reagent container stopper that can be subjected to high pierce counts with reduced susceptibility to coring or fragmentation. The disclosed stopper is suitable for use in packaging of reagents which contain a high volume of reagents for high-throughput analysis systems.

[0008] The disclosed stopper has a thin diaphragm, an aggressive undercut core, and compression protrusion features on the top of the stopper. Together, these features aid in stretching the diaphragm for ease of piercing and reduced coring & fragmentation.

[0009] The disclosed stopper permits the use of large containers in which a stopper must be capable of a large number of piercings without suffering coring and fragmentation. The amount of force required to pierce and slide through the disclosed stopper with a standard medical grade piercing cannula is drastically reduced compared to previously used stoppers.DETALED DESCRIPTION

[0010] Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein like reference characters designate like or corresponding parts throughout the several views.

[0011] The present disclosure includes a method not encompassed by the wording of the claims and an apparatus not encompassed by the wording of the claims for providing resealable access to a reagent container suitable for use in high-throughput automated analyzers. An improved container stopper is disclosed which substantially reduces the insertion force required by an aspirator probe to pierce the stopper compared to previously known container stoppers. The disclosed container stopper is designed and configured to be subject to a high number of piercings without fragmenting or coring of the container stopper.

[0012] FIGURE 1 shows a top view of a container stopper according to an illustrative embodiment of the present disclosure. FIGURE 2 shows a bottom view of the container stopper shown in FIGURE 1. FIGURE 3 shows a cross-sectional side view of the container stopper shown in FIGURES 1 and 2.

[0013] Referring to FIGURES 1 and 2, a pierceable stopper 10 for sealing a container opening includes a hollow plug portion 20 defining a central axis 22, and a disk portion 30 covering the hollow plug portion 20. The disk portion 30 is concentrically arranged with the hollow plug portion 20 about the central axis and defines a flange 40 extending radially beyond an outside diameter of the hollow plug portion 20. The stopper 10 also includes an internal cavity 50 of the hollow plug portion 20. Referring to FIGURE 3, the internal cavity 50 intersects the disk portion 30 such that the disk portion 30 includes a reduced thickness portion 60 over the internal cavity 50.

[0014] A central area 69 of the disk portion 30 defines a pierceable membrane 61 over the reduced thickness portion 60. A plurality of protrusions 70 extend from a top surface 71 of the disk portion 30 in a first radial zone 72 of the top surface 71 over the reduced thickness portion 60 and in a direction opposite the internal cavity 50. The first radial zone 72 is outside of and concentric with the central area 69 of the disk portion 30. A second radial zone 73 of the top surface 71 defines a planar ring area outside of the first radial zone 72.

[0015] The internal cavity 50 includes an undercut portion 80 extending radially into the flange portion 40.

[0016] In an illustrative embodiment, the plurality of protrusions 70 are substantially equidistantly placed in conjunction with the pierceable membrane 61 and the undercut portion 80. The pierceable membrane 61 defines an elastic diaphragm integrally attached to and movable with each of the plurality of protrusions 70.

[0017] In an illustrative embodiment, each of the plurality of protrusions 70 has an identical geometry and is spaced substantially equidistant from each adjacent protrusion within the first radial zone 72 of the top surface 71. In the illustrative embodiment, each of the protrusions 70 includes a ramped inner surface and a substantially vertical outer surface, for example.

[0018] According to an aspect of the present disclosure, the plurality of protrusions 70 when compressed by an external force are configured to reduce the external piercing forces applied by an aspirator probe on the stopper 10.

[0019] In an illustrative embodiment, the hollow plug portion 20 has a compressible exterior surface. In an illustrative embodiment, the pierceable stopper 10 may be made from a bromobutyl material, for example. The pierceable stopper 10 may also include a siliconized outer surface.

[0020] FIGURE 4A shows an example of a reagent container 100 that may be resealably closed by the disclosed stopper 10, and a separate cover member 110 that can be installed over the stopper 10 after the stopper 10 is installed on the reagent container 100. FIGURE 4B shows the stopper 10 installed on the reagent container 100. FIGURE 4C shows the cover member 110 installed over the stopper 10 while the stopper is installed on the container 100.

[0021] The cover member 110 includes a central aperture 120 sized such that the cover member 110 covers the second radial zone 73 of the top surface 71 of the stopper 10, but does not cover the first radial zone 72 or the central area 69 of the top surface 71 of the stopper 10. The central aperture 120 allows the plurality of protrusions 70 to extend through the cover member 110.

[0022] FIGURE 5 is a diagram showing a process for piercing the disclosed stopper 10 by an aspiration probe 200 of an automated analyzer for aspirating a reagent from a reagent container 100. In a first state of the process, the aspiration probe 200 is in a retracted position within a probe foot 210 and the probe foot 210 is also in a retracted position such that the stopper 10 is untouched by the probe foot 210 or the aspiration probe 200. The probe foot is a substantially cylindrical member that sheathes the aspiration probe 200 and is configured for vertical movement independently of the aspiration probe 200. The probe foot 210 includes a hole 220 configured to allow the aspiration probe 200 to extend and retract therethrough.

[0023] In a second state of the process, the aspiration probe 200 remains in its retracted position and the probe foot 210 is extended downward onto the stopper 10 and cover member 110. The probe foot 210 in its extended position exerts a downward force on the protrusions 70 that compresses the protrusions 70 downward. Due at least in part to the undercut portion 80 of the internal cavity 50 the protrusions 70 roll inward toward the central axis 22 (FIGURE 1) such that the top portions of the protrusions 70 are forced toward each other. At the same time the base of the protrusions are also pushed away from the central axis 22 thereby applying a radial stretching force to the central area 69 of the stopper 10.

[0024] When the probe foot 210 is fully extended against the stopper 10 and cover member 110, the protrusions 70 are fully deflected toward the central axis 22. According to an aspect of the present disclosure, the disclosed geometry of the protrusions leaves a central clearance pathway between the top portions of the fully deflected protrusions 70.

[0025] FIGURE 6 shows the protrusions in a slightly compressed state 310, an intermediately compressed state 320 and in a fully compressed state 330. In the fully compressed state 330 the central clearance pathway 340 for is maintained for allowing the aspiration probe 200 to pass therethrough.

[0026] FIGURE 7 shows a cross sectional finite element analysis view of the disclosed stopper 10 when the protrusions 70 are in the fully compressed state. A dark colored region 350 around the central area 69 indicates stretching of the central area 69 which reduces forces needed for piercing the stopper 10 with an aspiration probe 200. In an illustrative embodiment, the stopper 10 includes a pre-existing hole 365 that is stretched toward a more open state by the radial stretching force on the central area 69. A light colored region 360 above the undercut portion 80 indicates that stress is relieved above the undercut portion which facilitates repeated flexing of the protrusions toward each other without causing cracks, tears or fragmentation of the stopper.

[0027] Referring back to FIGURE 5, in a third state, the aspiration probe 200 is extended while the probe foot 210 remains in its extended position. The aspiration probe 200 pierces the central area 69 of the stopper 10 and extends into the reagent container while the central area 69 of the stopper 10 remains radially stretched. After the reagent is aspirated into the aspiration probe 200, both the aspiration probe 200 and the probe foot 210 are retracted to the first state to repeat the process.

[0028] FIGURE 8 shows a graph 800 comparing the average initial force 820 required for piercing the disclosed stopper 10 by an aspiration probe 200 and the average drag applied by the disclosed stopper 10 on the aspiration probe 200 compared to the same forces on two previously known reagent container stopper types. According to an aspect of the present disclosure, both the average initial insertion force 820 and insertion drag 830 of the disclosed stopper are drastically reduced compared to the previously known reagent container stopper types.

Claims

1. A pierceable stopper (10) for sealing a container opening (100), the stopper (10) comprising: a hollow plug portion (20) defining a central axis; a disk portion (30) covering the hollow plug portion (20), the disk portion (30) concentrically arranged with the hollow plug portion (20) about the central axis and defining a flange (40) extending radially beyond an outside diameter of the hollow plug portion (20); an internal cavity (50) of the hollow plug portion (20) intersecting the disk portion (30) such that the disk portion (30) comprises a reduced thickness portion (60) over the internal cavity (50); wherein the internal cavity (50) includes an open end, a cylindrical portion and an undercut portion (80), the undercut portion (80) extending radially into the flange (40); a central area (69) of the disk portion (30) defining a pierceable membrane (61) over the reduced thickness portion (60); a plurality of protrusions (70) extending from a top surface (71) of the disk portion (30) in a first radial zone (72) of the top surface (71) over the reduced thickness portion (60) and in a direction opposite the internal cavity (50), the first radial zone (72) outside of and concentric with the central area (69) of the disk portion (30); a second radial zone (73) of the top surface (71) defining a planar ring area outside of the first radial zone (72); the pierceable stopper (10) being characterized in that the diameter of the internal cavity (50) at its open end and the diameter of the internal cavity at the cylindrical portion are smaller than the maximum diameter of the internal cavity (50) at the undercut portion (80).

2. The pierceable stopper of claim 1, wherein the plurality of protrusions (70) are substantially equidistantly placed in conjunction with the pierceable membrane (61) and the undercut portion (80), wherein the plurality of protrusions (70) when compressed by an external force is configured to reduce the external force on the stopper (10).

3. The pierceable stopper of claim 1, wherein each of the plurality of protrusions (70) has an identical geometry and is spaced substantially equidistant from each adjacent protrusion within the first radial zone (72) of the top surface (71).

4. The pierceable stopper of claim 1, wherein the hollow plug portion (20) comprises a compressible exterior surface.

5. The pierceable stopper of claim 1, wherein the pierceable membrane (60) defines an elastic diaphragm integrally attached to and movable with each of the plurality of protrusions (70).

6. The pierceable stopper of claim 1, wherein each of the plurality of protrusions (70) comprise a ramped inner surface and a substantially vertical outer surface.

7. The pierceable stopper of claim 1, made from a bromobutyl material.

8. The pierceable stopper of claim 7, comprising a siliconized outer surface.