Tip caps for medical syringes

Abstract

The present disclosure relates to a tip cap (1) for closing a fluid passageway extending through a distal tip of a medical container, the medical container including an adapter attached to the distal tip and having a threaded inner portion, the tip cap (1) comprising an inner cap (10) sealably engaging the tip, the inner cap (10) being made of an elastomeric material and including a proximally extending skirt (11), the inner surface of the skirt (11) being configured to sealably engage an outer surface of the tip of the medical container along a contact surface, and a rigid outer cap securely disposed around the inner cap, the rigid outer cap including a threaded outer portion adapted to engage the threaded inner portion of the adapter, and the proximal edge of the skirt of the inner cap being aligned with the proximal edge of the outer cap.

Description

[Technical Field]

[0001] The present disclosure relates to a tip cap for a medical device. The present disclosure further relates to a tip cap assembly and a medical injection device including said tip cap assembly. [Background technology]

[0002] In this context, the distal end of a medical injection device should be understood to mean the end furthest from the hand of a user handling the medical injection device, and the proximal end should be understood to mean the end closest to said user's hand. Thus, in this specification, the distal direction should be understood as the direction of injection with reference to the injection system, and the proximal direction is the opposite direction, i.e., towards the user's hand.

[0003] A medical injection device includes a container for safely storing a medical solution therein. Such containers generally include an elongated, hollow body and a tip extending distally from the body. The tip of the container includes a fluid passageway extending therethrough to allow the medical solution within the container to be administered to a patient as needed. For connection to a needle or needleless access device, the tip may include an adapter including internal threads that enable a threaded connection.

[0004] Before use, the medical injection device is pre-filled with a medical solution and is provided with a tip cap for closing the passageway, ensuring the airtightness of the medical container at its distal end and thereby avoiding leakage and / or contamination of the medical solution. For this purpose, a screw-on tip cap can be attached to the adapter at the distal end of the medical container.

[0005] Such screw-on tip caps typically include an inner cap with a skirt made of a flexible material that ensures a tight connection between the tip cap and the medical container when the tip cap is secured to the tip of the medical container. Figure 1 shows such a tip cap, which includes a rigid outer cap 200 and a flexible inner cap 100 that includes a skirt 110. The skirt 110 of the inner cap 100 is configured to surround the tip of the medical device and protrudes proximally from the proximal end of the outer cap.

[0006] However, as shown by the arrow on the left side of Figure 2, the rotational motion of the screwing process when sealing the medical device often results in twisting of the flexible skirt 110. Thus, the skirt 110 can twist during the sealing step when the outer cap 200 is screwed onto the adapter and then return to the opposite direction after screwing the tip cap onto the tip of the medical container. Therefore, a tight screwing can partially reverse, which can lead to a leaky connection and result in contamination and / or loss of the medical solution.

[0007] In other cases, the skirt may be compressed during attachment of the tip cap, as indicated by the arrow on the right side of Figure 2. After the attachment process, the skirt stretches proximally along the tip of the medical device to relieve its internal constraints and / or twisting. On the other hand, due to the coefficient of friction and the contact surface between the glass tip of the syringe and the rubber inner cap, an adhesion effect may occur, and therefore the tip cap requires a high pull-out force to remove before using the medical injection device. Therefore, it is difficult for users to remove the tip cap, especially for those who may have reduced finger strength due to a health condition. For medical professionals, repeating the same gesture that requires applying high force to the tip cap can cause repetitive injuries.

[0008] Furthermore, flexible skirts are frequently treated with lubricants to facilitate the installation process. However, during storage of multiple tip caps in a bag, the lubricant can contaminate the surfaces of the rigid portions of the tip caps, particularly the threads of the tip caps that screw onto the adapters attached to the medical containers. This can lead to lubricant contamination of the adapter threads, which can mean a poor connection between the connector and the adapter when an additional needle or connector is screwed onto the adapter after the tip cap is removed. In fact, with lubricant deposited on the threads, the end user may want to screw the connector in tighter, thereby accidentally damaging either the connector or the adapter.

[0009] Therefore, there is a need for an improved tip cap that allows for secure, fixed threading onto a medical container, easy removal of the tip cap before use, and avoids unwanted application of lubricant. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present disclosure is to provide an improved tip cap for sealing an injection device that has reduced adhesion and torque characteristics to ensure a reliable connection between the tip cap and the injection device. [Means for solving the problem]

[0011] To that end, an object of the present disclosure is a tip cap for closing a fluid passageway extending through a distal tip of a medical container, the medical container including an adapter attached to the distal tip and having a threaded interior portion, the tip cap comprising: an inner cap sealably engaged with the tip, the inner cap being made of a flexible material and including a proximally extending skirt, the inner surface of the skirt configured to sealably engage an outer surface of the tip of the medical container along a contact surface; a rigid outer cap securely disposed about the inner cap, the rigid outer cap including a threaded outer portion adapted to engage the threaded inner portion of the adapter; Equipped with the proximal edge of the skirt of the inner cap aligned with the proximal edge of the outer cap; A tip cap comprising:

[0012] Additionally, the tip cap provided prevents lubrication from being applied to rigid parts during storage.

[0013] Advantageously, the alignment of the proximal end of the skirt of the inner cap with the proximal end of the outer cap exhibits a mechanical tolerance of + / - 0.3 mm or less.

[0014] Preferably, the proximal end of the skirt of the inner cap and the proximal end of the rigid outer cap are disposed in the same plane perpendicular to the tip.

[0015] The inner cap may be made of a thermoplastic elastomer or rubber.

[0016] The rigid outer cap may be made of a clear, rigid plastic material.

[0017] The clear outer cap allows the user to inspect the cap to detect leaks.

[0018] Preferably, the rigid outer tip cap is made of a rigid polymer selected from the list including polypropylene, polyethylene, polyvinyl chloride, polystyrene, polycarbonate, acrylonitrile butadiene styrene, or acrylonitrile styrene.

[0019] Advantageously, the inner cap is assembled by frictional engagement and / or clipping on the inner surface of the outer cap.

[0020] A second aspect of the present invention relates to a tip cap assembly comprising a tip cap as described above and an adapter adapted to engage with the distal end of the medical container such that the adapter concentrically surrounds the tip of the medical container, the adapter comprising a threaded inner portion adapted to engage with the threaded outer portion of the outer cap.

[0021] A third aspect of the present invention is a medical injection system comprising: a medical container including a longitudinal barrel, a tip projecting distally from the barrel and with a fluid passageway extending through the tip, and an adapter having a threaded interior portion extending around the tip; a tip cap as described above, The medical injection system includes a threaded outer portion of the outer cap that engages the threaded inner portion of the adapter and a skirt of the inner cap that sealably engages the tip. [Brief explanation of the drawings]

[0022] Further features and advantages will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings.

[0023] [Figure 1] FIG. 1 is a schematic diagram of a conventional tip cap. [Figure 2] FIG. 2 shows a schematic representation of the forces acting on the skirt of an inner cap in a conventional tip cap. [Figure 3] FIG. 3 is a schematic diagram of a tip cap according to one embodiment of the present disclosure. [Figure 4] FIG. 4 is a side view of a syringe having a tip cap assembly according to the present invention. [Figure 5] FIG. 5 is a schematic diagram of a flexible inner cap of the tip cap shown in FIG. [Figure 6] FIG. 6 is an enlarged view of the tip cap of FIG. [Figure 7] FIG. 7 is a probability plot of pull-out force for a conventional tip cap and a tip cap, according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] FIG. 3 shows a tip cap 1 according to the present invention.

[0025] The tip cap 1 can be attached to such a medical injection device 40 as shown in FIG.

[0026] The medical injection device 40 includes a container that includes an elongated hollow body 42 that is pre-filled with a medical solution. A tip 41 extending from the body 42 includes a fluid passageway that allows the medical solution to flow through the tip 41 and be administered to a patient.

[0027] Typically, the medical container 40 comprises an adapter 30 that is attached to the distal end of the syringe and at least partially surrounds the syringe tip 41. Such an adapter 30 comprises an internal thread 31, which may also allow for connection of a device for administering a medical solution to a patient's body, such as an injection needle, a device for administering an intravenous infusion, or a needleless injection device.

[0028] The tip cap 1 is threaded onto the adapter 30 after the container has been filled with medical solution and during storage of the injection device 40. The tip cap seals the tip of the medical container to prevent leakage and contamination of said medical solution.

[0029] The medical injection device may further comprise a plunger rod 44 that is inserted into the open proximal end of the body 42 and includes a stopper 43 that maintains fluid-tight engagement with the cylindrical wall of the body 42. After removal of the tip cap 1, distal sliding movement of the plunger rod 44 forces the medical solution out of the body 42 through a fluid passage in the tip 41 of the medical injection device 40.

[0030] As can be seen in FIG. 3, the tip cap 1 includes an outer cap 20 and an inner cap 10 .

[0031] The outer cap 20 is made of a transparent, rigid material, preferably a rigid polymer. The outer cap 20 can be manufactured by a molding process, such as injection molding. The polymer can be selected from polypropylene, polyethylene, polyvinyl chloride, polystyrene, polycarbonate, acrylonitrile butadiene styrene, acrylonitrile styrene, or similar polymers, or combinations thereof. The transparent material allows for verification of the correct assembly of the outer cap and inner cap, as well as the assembly of the tip cap on the medical container adapter. Furthermore, when the tip cap is attached to a medical container filled with medical solution, the transparent outer cap allows the user to inspect the cap and determine whether a leak has occurred and whether the medical solution has penetrated into the space between the inner and outer caps. Most preferably, the outer cap is made of polypropylene, because it is an easily moldable, strong, and lightweight plastic material. Polypropylene also has the advantages of being highly impermeable to liquids and inert to many chemicals, preventing deterioration of the outer cap when in contact with medical solutions.

[0032] The outer cap 20 has an external threaded surface 21 at its proximal end and is adapted to be threaded onto the internal threads 31 of the adapter 30 of the medical container 40 .

[0033] Additionally, the outer cap 20 may include a rim 26 that provides a limit stop when threading the tip cap 1 onto the adapter 30, either by contact between the rim 26 and the adapter 30 or by contact between the inner cap 10 and the distal end of the medical container 40.

[0034] The outer cap 20 may further include a distal gripping portion 25 including ribs, grooved indentations, or any other structure that allows a user to firmly hold the tip cap 1 when securing it to the syringe adapter 30, preventing the tip cap from slipping out of the user's hand. The gripping portion 26 may also prevent the tip cap from rolling off when placed on a smooth surface, making it easier for the user to handle.

[0035] The outer cap 20 provides a rigid outer wall to the tip cap 1 to protect the flexible skirt of the inner cap 10 from mechanical forces due to the external environment, thereby avoiding deformation of the inner cap, such as compression or squeezing.

[0036] The outer cap 20 can be provided with an opening at its distal end of any size less than or equal to the diameter of the outer cap 20. Such an opening avoids air compression between the inner and outer caps, which could create resistance to inserting the inner cap 10 into the outer cap 20, and simplifies assembly of the outer cap 20 and the inner cap 10, while not affecting the function of the outer cap.

[0037] FIG. 5 shows the inner cap 10. The inner cap 10 is made of a flexible material, such as a rubber formulation such as bromobutyl elastomer or chlorobutyl elastomer, or any other rubber formulation or thermoplastic elastomer that provides suitable elasticity for sealing the tip of a medical container. Those skilled in the art will select a rubber formulation that is inert to the medical solution being filled into the medical container, has sufficient heat resistance to undergo the necessary sterilization procedures, and has appropriate grip and release characteristics for sliding the inner cap over the tip of the medical container and releasing it after use. The inner cap 10 can be manufactured by a molding process such as injection molding.

[0038] The inner cap 10 includes a proximal skirt 11 having a hollow cylindrical shape. The inner wall of the hollow cylinder is straight, and the outer wall of the hollow cylinder is slightly tapered. The inner cap further includes a distal solid sealing base 12 that can present a central protrusion 13 surrounded by the skirt 11, forming an inner cavity with a circular shape adapted to engage with the distal end of the tip of a medical container 40. The central protrusion 13 can penetrate the distal end of the tip 41 of a medical container 40.

[0039] The diameter of the skirt 11 is selected so that it expands slightly radially when attached to the tip of the medical container. In this way, the inner wall of the skirt tightly surrounds the outer surface of the tip 41 of the medical container 40. The tight cylindrical shape and flexible material allow the inner cap to provide a fluid-tight seal on the tip of the medical container, avoiding loss and / or contamination of the medical solution.

[0040] The inner cap 10 is typically secured to the inner wall of the outer cap 20 by a clipping mechanism or any other connection based on frictional engagement between the inner cap 10 and the outer cap 20. Both the inner and outer caps may include ribs 28, grooves 18, or nubs suitable for providing such a connection between the inner and outer caps. Alternatively, the inner cap may be glued to the outer cap, for example, by a suitable adhesive.

[0041] The inner cap 10 and outer cap 20 are in intimate contact at the distal portion of the tip cap. At the proximal end of the tip cap, a radial gap 50 exists between the inner cap 10 and outer cap 20. The radial gap allows deformation of the flexible inner cap to conform to the shape of the tip of the medical device during assembly.

[0042] As shown in Figure 6, when the outer cap 20 and inner cap 10 are assembled, the skirt 11 of the inner cap 10 is proximally aligned with the rigid outer cap 20. Alignment should be understood to mean that the proximal ends of the skirt of the inner cap and the outer cap are positioned in the same plane perpendicular to the tip of the medical device. The tip cap engages the tip of the medical device along a contact surface.

[0043] The outer cap length has a mechanical tolerance of 0.1 mm, and the inner cap skirt length has a mechanical tolerance of 0.2 mm. These tolerances are typically due to manufacturing. Therefore, a total mechanical tolerance of + / - 0.3 mm is allowed for alignment. Thus, the edge of the inner cap skirt and the edge of the outer cap are aligned proximally by + / - 0.3 mm when assembled.

[0044] For example, for a Type 7025 tip cap, the skirt has an overall length of 5.82 mm. A tolerance of + / - 0.3 mm results in a length variation of 5.2%. For an FM30 type tip cap, the total cap length is 5.77 mm. A tolerance of + / - 0.3 mm results in a length variation of 5.2% of the overall tip cap length.

[0045] In a preferred embodiment, the proximal end of the outer cap is flush with the inner cap, i.e., the proximal end of the outer cap and the proximal end of the skirt of the inner cap are positioned exactly in the same plane perpendicular to the tip of the medical device.

[0046] When securing the tip cap 1 to the prefilled medical container 40, the outer cap 20 is threaded onto the inner threads 31 of the adapter 30 attached to the distal end of the medical container 40 with the outer thread surface 21. This step is typically performed with a screwdriver. The inner cap 10 is thereby pushed proximally, and the skirt 11 slides along the outer surface of the tip 41, tightly surrounding the tip 41. When the tip cap 1 is attached, the sealing base 12 seals the fluid passage on the tip 41 of the medical container, and the central protrusion 13 is inserted into the tip 41 of the medical container. The skirt 11 tightly surrounds the tip 41 to provide a seal for the medical solution contained in the medical container 40.

[0047] Due to its relatively short length, the skirt 11 of the inner cap 10 remains in its original shape during the screwing procedure, except for slight radial stretching. There is no squeezing or twisting of the skirt. Therefore, the skirt 11 immediately reaches its final shape and position at the end of the screwing, tightly enclosing the tip of the medical container. The tip cap remains in place while screwed onto the syringe and does not move or loosen into different positions after being secured to the medical container.

[0048] [Pull-out performance] The tip cap according to the invention presents a contact surface with the tip of the medical container that is smaller than the contact surface of conventional tip caps in which the skirt of the inner cap extends beyond the rigid outer cap. Preferably, the extension of the contact surface in the proximal direction, L C is the length of the distal tip L T and more preferably, the length of the distal tip L T The length of the distal tip, L T corresponds to the distance between the distal outer wall of the syringe barrel and the distal end of the tip, as shown in FIG. 6.

[0049] This reduces the pull-out force required to remove the tip cap from the medical container.

[0050] The reduced contact surface results in a reduced frictional force between the tip cap and the tip of the medical container, thereby reducing the pull-out force required to remove the tip cap. The reduced pull-out force makes it easier for users to access the medical solution, especially for users with reduced finger strength or medical professionals who perform the same gesture repeatedly.

[0051] The reduced pull-out force and easy removal prevent the user from accidentally breaking the tip itself or breaking the tip from the medical container, as the user is required to apply less force and effort. The reduced effort also reduces the risk that the user will accidentally twist or bend the tip while removing the tip cap. This prevents breakage of the syringe tip, which would render the syringe and the medical solution contained therein useless.

[0052] Pull-out forces have been tested on a range of sample tip caps for various syringe types. Figure 7 shows the distribution of pull-out forces in N for two lots of tip caps: one lot of conventional tip caps (represented by circles) and one lot of tip caps in accordance with the present invention (represented by squares). The pull-out forces for the conventional tip caps range from 1.6 N to 5.2 N, while the pull-out forces for the tip caps in accordance with the present invention range from 0.8 N to 4.1 N. As can be seen in the probability plot, the pull-out forces for the tip caps in accordance with the present invention are significantly lower.

[0053] In particular, while providing reduced pull-out force, the reduced surface area does not affect integrity performance and the tightness of the connection is at the same level as that of a conventional end cap.

[0054] Because sterilization and aging typically affect the pull-out force required to remove a tip cap, the pull-out properties of tip caps according to the present invention have been tested after sterilization procedures and after application of accelerated aging protocols.

[0055] [Leak test] Several lots of end caps according to the present invention have been tested for their sealing performance.

[0056] The first type of leak test procedure combines a closed-leak and pressure leak test, allowing the risk of loss of the medical solution contained in the medical container to be assessed. A series of medical containers were then sterilized and filled with the test solution. A closed-leak test was performed, applying a pressure of 1.1 bar for 5 seconds and measuring the leakage rate of the test solution. All samples complied with the specification, which requires a leakage rate of less than 44 Pa / s.

[0057] After the closure leak test, a visual leak test was performed. The medical container was then stoppered with a syringe stopper, leaving a 3-4 mm air bubble, as typically occurs in stoppered medical containers. A pressure leak test was then performed, in which pressure was applied to the syringe stopper's piston and the leakage of the test liquid through the tip of the medical container was observed as a function of the applied mechanical pressure. The results were corrected by subtracting the stopper's sliding force, which was measured separately on an empty injection device. All recorded pressure leak values ​​were within the 1.1 bar specification.

[0058] The second type of leak test procedure, the dye immersion test, tests the penetration of externally applied substances into syringes and allows for the assessment of the risk of contamination of the medical solution contained therein. In this type of test, a second set of medical containers is sterilized and stoppered with empty syringe stoppers. The stoppers are placed at a level corresponding to a 1 ml fill level of the medical solution in the medical container. Then, tip caps are attached to the medical containers. During the test procedure, the tips with attached tip caps are immersed in a liquid dye, typically methylene blue, so that the medical containers are not completely submerged. A vacuum of -350 mbar is applied for 16 hours. Penetration of the dye into the medical barrel indicates a potential risk of leakage and contamination from the outside of the tip caps. No leakage was observed among all test samples.

[0059] [Lubricant distribution] Tip caps for medical injection devices are often treated with a lubricant during or after manufacture and assembly. Such lubricants are typically applied to the flexible inner cap to facilitate sliding of the tip cap onto the tip of the medical container. During storage, some tip caps are typically stored in a clean, dust-proof bag, such as a sealed plastic bag. Because the flexible inner cap is completely surrounded by the outer cap, the lubricant generally remains in place and does not rub off onto the threads of the outer cap and, consequently, onto the threads of the adapter. Therefore, because the threads of the adapter remain free of lubricant, a needle or other connector threaded onto the adapter after the cap is removed is securely fastened without the risk of loosening the threaded connection. This also prevents users from using more force to thread the connector, thereby reducing the risk of accidentally damaging the adapter, needle, or connector being threaded onto the medical container.

Claims

1. 1. A tip cap (1) for closing a fluid passageway extending through a distal tip of a medical container, the medical container including an adapter attached to the distal tip and having a threaded interior portion, the tip cap (1) comprising: an inner cap (10) sealably engaging the tip, the inner cap (10) being made of a flexible material and including a proximally extending skirt (11), the inner surface of the skirt (11) being configured to sealably engage an outer surface of the tip of the medical container along a contact surface; a rigid outer cap (20) tightly disposed around the inner cap (10), the rigid outer cap (20) having a threaded outer portion (21) adapted to engage the threaded inner portion of the adapter; Equipped with The tip cap (1), wherein the proximal edge of the skirt (11) of the inner cap (10) is aligned with the proximal edge of the outer cap (20).

2. 2. The tip cap (1) of claim 1, wherein the alignment of the proximal end of the skirt (11) of the inner cap with the proximal end of the outer cap (20) exhibits a mechanical tolerance of + / - 0.3 mm or less.

3. 2. The tip cap (1) of claim 1, wherein the proximal end of the skirt (11) of the inner cap (10) and the proximal end of the rigid outer cap (20) are disposed in the same plane perpendicular to the tip.

4. The tip cap (1) according to any one of claims 1 to 3, wherein the inner cap (10) is made of a thermoplastic elastomer or rubber.

5. The tip cap (1) according to any one of claims 1 to 4, wherein said rigid outer cap (20) is made of a transparent rigid plastic material.

6. 6. The tip cap (1) according to any one of claims 1 to 5, wherein the rigid outer cap (20) is made of a rigid polymer selected from the list comprising polypropylene, polyethylene, polyvinyl chloride, polystyrene, polycarbonate, acrylonitrile butadiene styrene, or acrylonitrile styrene.

7. The tip cap (1) according to any one of claims 1 to 6, wherein the inner cap (10) is assembled by frictional engagement and / or clipping on the inner surface of the outer cap (20).

8. 8. A tip cap assembly comprising: a tip cap (1) according to any one of claims 1 to 7; and an adapter adapted to engage with a distal end of a medical container such that the adapter concentrically surrounds the tip of the medical container, the adapter comprising a threaded inner portion adapted to engage with the threaded outer portion (21) of the outer cap (20).

9. 1. A medical injection system comprising: a medical container including a longitudinal barrel, a tip projecting distally from the barrel and with a fluid passageway extending through the tip, and an adapter having a threaded interior portion extending around the tip; A tip cap (1) according to any one of claims 1 to 8; Equipped with A medical injection system, wherein the threaded outer portion (21) of the outer cap (20) engages the threaded inner portion of the adapter, and the skirt of the inner cap (10) sealably engages the tip.

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