GB2593466A

GB2593466A - Sterile needle hubs

Info

Publication number: GB2593466A
Application number: GB2004173.7A
Authority: GB
Inventors: Fazlul Hoque Chowdhury Dewan
Original assignee: NDM Technologies Ltd
Current assignee: NDM Technologies Ltd
Priority date: 2020-03-23
Filing date: 2020-03-23
Publication date: 2021-09-29
Also published as: GB202004173D0; WO2021191581A1

Abstract

A needle hub for an injector device, comprising a central body 8 supporting a double ended needle 2 for penetrating a vial 30 at a proximal end 4 and the skin of a subject at a distal end 6. Each end of the needle 2 is enclosed within a sealed enclosure 12 22 which extends from the central body, each having a membrane end wall 14 24 which is spaced from the needle tip and can be pierced by the needle in use. At least the distal chamber 22 preferably comprises a side wall 20 that can collapse when the needle hub is pressed against the skin, and may have fold lines 27 along it to allow it to collapse. This reduces the length of the distal chamber 22 and allows the distal end 6 of the needle to pierce the distal end wall 24 and the skin. The proximal enclosure may have a rigid side wall and a flexible end membrane which deflects when a vial is pushed against it. The enclosures may be cylindrical and may be different diameters.

Description

TITLE

Sterile needle hubs

DESCRIPTION

Technical field

The invention relates to needle hubs for medical devices, which are used to inject a fluid from a vial, through a hollow needle, into the skin of a subject. The needle is double-ended and is mounted in the hub so that a first end extends in a proximal direction to penetrate the vial and a second end extends in a distal direction to penetrate the skin of the subject.

Background of the invention

Many injector devices are known, which are used to deliver a fluid into the skin of a subject, while providing additional functionality compared with a manually operated hypodermic syringe. The fluid is typically but not exclusively a biologically active substance such as a pharmaceutical. The subject may be human or animal.

Biologically active fluids such as pharmaceuticals are frequently packaged in cylindrical vials, which contain an axially sliding plunger. As the plunger moves from the proximal end (closer to the operator) to the distal end (closer to the subject), it displaces fluid from the distal end of the vial. Prior to use, for example during transport and storage, the distal end of the vial is normally sealed by a septum to maintain the sterility of the interior of the vial. Immediately before use, the septum must be ruptured to release the fluid by piercing it with the proximal end of the needle. The needle is held in a needle hub, which is moved towards the vial until the proximal end of the needle pierces the septum. The fluid can then flow from the vial, through the needle, to its distal end for injection into the skin of the subject.

Needles for this purpose are typically very fine and are vulnerable to damage Mounting the needle in a hub allows it to be more easily handled during subsequent stages of manufacture, transport and storage. The hub may also be shaped to provide some physical protection to the needle, for example by comprising an open-ended -2 -cylinder that surrounds the needle over part of its length. If the injector device is intended for single use, the needle hub may be permanently assembled into it during manufacture and the needle hub may be integrated with other components of the device and/or may perform functions other than supporting the needle. If the injector device is intended for multiple uses, then the needle hub may be designed to be assembled into the device shortly before the first use and to be removed and replaced before each subsequent use The needle must be sterile at the time of use. It can be sterilized during manufacture and thereafter it is essential to keep it contained within an air-and water-tight seal, to avoid the need for re-sterilization. This is typically achieved by sealing the proximal end of the needle within the body of the injector device and by forming the injector device to include a disposable cap that seals and protects the distal end of the needle until it is ready to be used. For example, patent EP 3141276 Al discloses a needle for an insulin pen, which is surrounded by a shell 4. Sealing paper/film 6 covers the proximal end of the shell 4, to be tom off before the needle assembly is mounted on an injector pen. Then the shell 4 is removed to expose the distal end of the needle. Such arrangements require sterilization of the whole the device or at least the sub-assembly of the device that includes the needle hub. (Alternatively, the needle hub and the surrounding parts could be sterilized separately but would then need to be assembled in a sterile environment.) They also require additional disposable parts.

Summary of the invention

The invention provides an injection device as defined in claim I. The invention further provides a method of operating such an injection device, as defined in claim 8.

Features of the invention that are preferred but not essential are defined in the dependent 30 claims. -3 -

The drawings Figure 1 is a perspective diagram of a needle hub according to a first embodiment of the invention in an expanded condition.

Figure 2 shows the same as Figure 1 but shows the needle hub in a compressed condition.

Figure 3 is a perspective diagram of a needle hub according to a second embodiment of the invention in an expanded condition.

Figure 4 shows the same as Figure 3 but shows the needle hub in a compressed condition.

Figure 3 is a perspective diagram of a needle hub according to a third embodiment of the invention in an expanded condition.

Figure 1 schematically shows a needle hub 1 that is generally cylindrical in form, with a double-ended, hollow needle 2 along its axis. The needle 2 has a sharp proximal end 4 for piercing the septum of a vial (not shown) and a sharp distal end 6 for piercing the skin of a subject (not shown). In a central region between the two ends 4,6 -but not necessarily at its geometric centre -the needle is mounted in a drum-shaped central body 8 A rigid, cylindrical proximal side wall 10 extends from the central body 8 to define a proximal chamber 12 that concentrically surrounds the proximal end 4 of the needle. The end of the chamber 12 is closed by a proximal end wall 14, which is spaced axially from the tip of the proximal end 4 of the needle. The end wall 14 is formed by a thin, flexible membrane, which is capable of being pierced by the proximal end 4 of the needle. The end wall 14 creates a seal that isolates the proximal end 4 of the needle from the environment to prevent microbial ingress.

A generally cylindrical distal side wall 20 extends from the central body 8 to define a distal chamber 22 that concentrically surrounds the distal end 6 of the needle. The end of the chamber 22 is closed by a distal end wall 24, which is spaced axially from the tip of the distal end 6 of the needle. The distal end wall 24 is formed by a thin membrane, which is capable of being pierced by the distal end 6 of the needle. The distal end -4 -wall 24 may be formed from the same material as the proximal end wall 14 but it is not essential that the membrane of the distal end wall 24 should be flexible. The end wall 24 creates a seal that isolates the distal end 6 of the needle from the environment and microbial ingress. The distal side wall 20 is formed from a generally stiff material but, as shown schematically in Figure 1, over at least part of its axial extent the distal side wall 20 is structured in the manner of a concertina or bellows 26, with predefined fold lines 27, along which the material of the wall can bend in order for the side wall 20 to collapse and become shorter in the axial direction. The stiff material of the distal side wall 20 offers a degree of physical protection to the distal end 6 of the needle.

The proximal end wall 14 and the distal end wall 24 create seals, which isolate the proximal chamber 12 and the distal chamber 22 respectively from the environment, preventing microbial ingress. Therefore, if the needle 2 and the interiors of the chambers 22,24 are sterile when the seals are closed, they will remain sterile as long as the end walls 14,24 remain intact. Although the central body 8 is typically solid, it is not necessary that it should isolate the proximal and distal chambers 12,22 from one another because in any case they are connected via the hollow needle 2 Figure 2 shows how the end walls 14,24 of the needle hub 1 may be pierced when the zo hub has been mounted in an injector device (not shown) and is ready to use. The dashed cylinder 28 represents the distal end of a vial, which is typically sealed by a septum across its opening (The vial does not form part of the present invention.) The diameter of the vial 28 is smaller than the diameter of the proximal side wall 10 so that the vial 28 may be pushed axially into the proximal chamber 12. The relative axial movement of the needle hub 1 and the vial 28 may be guided by features of the injector device (not shown) such as co-operating screw threads. As the mouth of the vial 28 enters the proximal chamber 12, it deforms the flexible membrane of the proximal end wall 14. It does not matter whether or not the deformation is elastic. The vial pushes the end wall 14 against the proximal end 4 of the needle and causes the tip of the needle to pierce first the membrane of the end wall 14 and then the septum of the vial 28, thereby providing a channel for fluid to flow out of the vial 28 through the hollow needle 2. -5 -

Subsequently, the needle hub is pressed against the skin of the subject to deliver the fluid into the skin. As shown in Figure 2, pressure on the distal end wall 24 causes the concertina section of the distal side wall 20 to collapse and reduce the axial length of the distal chamber 22. This causes the tip of the distal end 6 of the needle first to pierce the membrane of the distal end wall 24 and then to penetrate the surface of the skin so that the fluid from the vial can be delivered.

The needle hub 1 and the individual proximal and distal chambers 2,4 do not necessarily have the form of a circular cylinder. For example, if the distal chamber 22 were square in cross-section, it would be possible to form the concertina section 26 of the side wall 20 with a structure of straight fold lines that would enable the chamber 22 to be compressed with less stretching of the material of the side walls.

Figures 3 and 4 show a second embodiment of the invention with a different form of the distal chamber 32. The proximal chamber 12 is identical to the first embodiment and will not be described again. In this embodiment, the side wall 30 of the distal chamber is not formed from a stiff material with predefined fold lines but from a relatively deformable material that will collapse by randomly crumpling when axial pressure is applied to it, to reduce its length as shown in Figure 4. The material may be zo the same as for the end wall 34: the side wall 30 and end wall 34 in this embodiment are preferably formed integrally as a single component. The stiffness of the component should be sufficient to hold its shape, for example under its own weight during normal handling of the needle hub. For this reason, the diameter of the distal chamber 32 is preferably reduced to give the component greater strength. It may be welded at a proximal end to a boss 36 of the central body, which has a correspondingly reduced diameter.

If the side wall 30 and end wall 34 of the distal chamber 32 are formed integrally, it is not necessary that a clear boundary should be identifiable between them. Figure 5 shows an example where the distal chamber is surrounded by a single, domed chamber wall 40. It is still possible to identify a region on the axis as the end wall and a region -6 -at the periphery as the side wall but one region merges seamlessly into the other. In other respects, the third embodiment is identical to the second embodiment.

It will be understood that the structures shown at opposite ends of the needle hub 1 in the illustrated embodiments are essentially independent of one another so they could be combined in alternative combinations. In particular, the proximal chamber 12 of the hub could be provided with a collapsible side wall similar to those illustrated in the distal chambers 22,32. In that case, the vial would be guided via an external guide chamber that is an integral part of the injector device (not shown). This would also be to advantageous to ensure that the pressure required to insert the needle into the septum in the vial would be very low and, for example, significantly lower than the force that may be required to overcome the elasticity of a flat elastic seal.

Although the needle 2 is referred to as "double-ended", it is not essential that it should be manufactured as a single piece. One alternative would be for the proximal and distal ends 4,6 of the needle to be separate components that are mounted independently in the central body 8 and coupled via a chamber (not shown) within the central body. In this scenario, the two ends 4,6 could have different diameters or other properties. For example, if the fluid to be delivered from the vial 30 is viscous, it might be advantageous to form the proximal end 4 of the needle with a larger diameter than the distal end 6.

A sterile barrier can be achieved using materials that are completely non-porous. Nonporous materials are used where the sterilisation process uses radiation such as gamma or electron beam. Alternatively, the materials may be sufficiently porous to allow the diffusion of air and other gases but not to allow the ingress of bacteria or any viable material that would render the product/area within the barrier non-sterile. Porous materials are generally used where the sterilisation process uses steam or hydrogen peroxide gas.

Examples of materials that may be suitable for the invention described herein are listed as follows.

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Plastic films: Polyethylene at a range of densities. Low density Polyethylene (LDPE), Linear low density PE (LLDPE) is soft, stretchable and has good heat sealing properties. These would be ideal for the invention at hand. Medium and high density polyethylene (MDPE and HDPE) are stiffer than the low density grades. Ethylene vinyl acetate (EVA) is tough and flexible and therefore also suited to this application.

- Paper: produced from cellulose, can be coated (with a thin layer of polymer) or uncoated and formed from multilayers, and provides a collapsible high integrity barrier.

- Non-wovens: these are generally sheets of fibres, continuous filaments, or chopped yarns of any nature or origin, that have been formed in to a web by any means and bonded together by any means with the exception of weaving or knitting. -8 -

Claims

CLAIMS1. A needle hub for an injection device comprising: a hollow needle comprising a proximal end and a distal end; a central body in which the needle is mounted with the proximal and distal ends projecting from the central body; a proximal enclosure extending from the central body to form a seal around the proximal end of the needle, the proximal enclosure comprising an end wall formed from a proximal membrane that is axially spaced from the proximal end of the needle; and a distal enclosure extending from the central body to form a seal around the distal end of the needle, the distal enclosure comprising an end wall formed from a distal membrane that is axially spaced from the distal end of the needle.
2. A needle hub according to claim 1, wherein the enclosure at either the proximal or distal end comprises a side wall that is capable of collapsing to cause the distal end of the needle to pierce the distal membrane
3. A needle hub according to claim 2, wherein the side wall has predefined fold lines, along which to fold when collapsing.
4. A needle hub according to claim 2, wherein the side wall is formed from the same membrane as the end wall.
5. A needle hub according to claim 4, wherein the side wall is in the general form of a cylinder, haying a distal end closed by the end wall and a proximal end welded to the central body.
6. A needle hub according to any of claims 2 to 5, wherein the proximal enclosure also comprises a side wall that is capable of collapsing to cause the proximal end of the needle to pierce the proximal membrane.
7. A needle hub according to any of claims 2 to 5, wherein: the proximal enclosure comprises a rigid side wall that is closed at a proximal end by the proximal membrane; and the proximal membrane is capable of deformation to cause the proximal end of the needle to pierce the proximal membrane.
8. A method using a needle hub for an injection device, the needle hub comprising: a hollow needle comprising a proximal end and a distal end; a central body in which the needle is mounted with the proximal and distal ends projecting from the central body; a proximal enclosure extending from the central body to form a seal around the proximal end of the needle; and a distal enclosure extending from the central body to form a seal around the distal end of the needle; wherein each enclosure comprises an end wall formed from a membrane that is axially spaced from the respective end of the needle and is capable of being pierced by the respective end of the needle; the method comprising: applying pressure to the distal enclosure to cause a side wall of the distal enclosure to collapse and thereby cause the distal end of the needle to pierce the distal membrane.