WO2021191581A1

WO2021191581A1 - Sterile needle hubs

Info

Publication number: WO2021191581A1
Application number: PCT/GB2021/050535
Authority: WO
Inventors: Dewan Fazlul Hoque Chowdhury
Original assignee: Ndm Technologies Ltd
Priority date: 2020-03-23
Filing date: 2021-03-04
Publication date: 2021-09-30
Also published as: GB202004173D0; GB2593466A

Abstract

In a needle hub (1) for an injector device, a central body (8) supports a proximal needle end (4) for penetrating a vial (30) and a distal needle end 6 for penetrating the skin of a subject. Each needle end (4,6) sealed within an enclosure (12,22) that maintains the sterility of the needle ends (4,6) prior to use. The respective enclosures (12,22) comprise end walls (14,24) formed from membranes that can be pierced by the tips of the needle ends (4,6). The distal enclosure (22) comprises a side wall (20) that can collapse when the needle hub (1) is pressed against the skin, to reduce the length of the distal enclosure (22) and allow the distal needle end (6) to pierce the distal end wall (24). The proximal enclosure (12) comprises a rigid side wall (10), while the membrane of its end wall (14) can be deformed by pressure from the neck of a vial to allow the tip of the proximal needle end (4) to pierce the end wall (14).

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 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 A1 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 1.

The invention further provides a method of operating such an injection device, as defined in claim 6.

Features of the invention that are preferred but not essential are defined in the dependent claims. 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 is 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 is the same as Figure 3 but shows the needle hub in a compressed condition. Figure 5 is a perspective diagram of a needle hub according to a third embodiment of the invention in an expanded condition. Figure 6 is a schematic cross-section along the axis of a needle hub according to the invention, which comprises a double-ended needle.

Figure 7 is a schematic cross-section along the axis of a needle hub according to the invention, which comprises two needle ends as separate components. 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 such that the two needle ends 4,6 project from the central body 8 in opposite directions along the axis.

A rigid, cylindrical proximal side wall 10 extends from the central body 8 to define a proximal enclosure 12 that concentrically surrounds the proximal end 4 of the needle. The end of the enclosure 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 enclosure 22 that concentrically surrounds the distal end 6 of the needle. The end of the enclosure 22 is closed by a distal end wall 24, which is spaced axially from the tip of the distal needle end 6. The distal end wall 24 is formed by a thin membrane, which is capable of being pierced by the tip of the distal needle end 6. The distal end 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 interiors of the proximal enclosure 12 and the distal enclosure 22 respectively from the environment, preventing microbial ingress. Therefore, if the needle 2 and the interiors of the enclosures 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 enclosures 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 hub has been mounted in an inj ector 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 enclosure 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 enclosure 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.

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 enclosure 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 enclosures 2,4 do not necessarily have the form of a circular cylinder. For example, if the distal enclosure 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 enclosure 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 enclosure 32. The proximal enclosure 12 is identical to the first embodiment and will not be described again. In this embodiment, the side wall 30 of the distal enclosure 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 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 enclosure 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 enclosure 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 enclosure is surrounded by a single, domed enclosure wall 40. It is still possible to identify a region on the axis as the end wall and a region 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.

In the invention as described so far, the proximal end 4 and the distal end 6 are the opposite ends of a single, double-ended needle 2. Figure 6 schematically shows such a double-ended needle mounted in the central body 8. Figure 7 schematically shows an alternative, in which the proximal and distal ends 4,6 of the needle are manufactured as separate components, which are mounted independently in the central body 8 and coupled in fluid communication via a fluid chamber 42 within the central body 8. In this arrangement, the two needle 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, as shown in Figure 7.

A sterile barrier can be achieved using materials that are completely non-porous. Non- porous 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:

- 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 yams 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.

Claims

1. A needle hub (1) for an injection device comprising: a hollow proximal needle end (4); a hollow distal needle end (6); a central body (8) in which the proximal and distal needle ends (4,6) are mounted in fluid communication with one another, the proximal and distal needle ends (4,6) projecting from the central body (8) in opposite directions along an axis; a proximal enclosure (12) extending from the central body (8) to form a seal around the proximal needle end (4), the proximal enclosure (12) comprising a side wall (10) and an end wall (14), the end wall (14) being formed from a proximal membrane that is axially spaced from a tip of the proximal needle end (4); and a distal enclosure (22,32) extending from the central body (8) to form a seal around the distal needle end (6), the distal enclosure (22.32) comprising a side wall (20,30) and an end wall (24,34), the end wall (24,34) being formed from a distal membrane that is axially spaced from a tip of the distal needle end (6); wherein the side wall (20,30) of the distal enclosure (22,32) is capable of collapsing to cause the tip of the distal needle end (6) to pierce the distal membrane (24,34); and the side wall (10) of the proximal enclosure (12) is rigid, the proximal membrane (14) being capable of deformation to cause the tip of the proximal needle end (4) to pierce the proximal membrane (14).

2. A needle hub (1) according to claim 1, wherein the side wall (20) of the distal enclosure (22) has predefined fold lines (27), along which to fold when collapsing.

3. A needle hub (1) according to claim 1, wherein the side wall (30) and the end wall (34) of the distal enclosure (32) are formed from the same membrane.

4. A needle hub (1) according to claim 3, wherein the side wall (30) of the distal enclosure (32) is in the form of a cylinder, having a distal end closed by the end wall (34) and a proximal end welded to the central body (8).

5. A needle hub (1) according to any of claims 1 to 4, wherein the proximal needle end (4) and the distal needle end (6) are opposite ends of a double-ended, hollow needle (2).

6. A needle hub (1) according to any of claims 1 to 4, wherein the proximal needle end (4) and the distal needle end (6) are separate components mounted to be in fluid communication with one another via a fluid chamber (42) in the central body (8).

7. A needle hub (1) according to claim 6, wherein the proximal needle end (4) and the distal needle end (6) have different diameters.

8. A method of using a needle hub for an injection device, the needle hub (1) comprising: a hollow proximal needle end (4); a hollow distal needle end (6); a central body (8) in which the proximal and distal needle ends (4,6) are mounted in fluid communication with one another, the proximal and distal needle ends (4,6) projecting from the central body (8) in opposite directions along an axis; a proximal enclosure (12) extending from the central body (8) to form a seal around the proximal needle end (4), the proximal enclosure (12) comprising a rigid side wall (10) and an end wall (14) formed from a proximal membrane that is axially spaced from a tip of the proximal needle end (4); and a distal enclosure (22,32) extending from the central body (8) to form a seal around the distal needle end (6), the distal enclosure (22,32) comprising a side wall (20,30) that is capable of collapsing and an end wall (24,34) formed from a distal membrane that is axially spaced from a tip of the distal needle end (6); the method comprising: applying pressure axially to the distal enclosure (22,32) to cause the side wall (20,30) of the distal enclosure to collapse and thereby cause the tip of the distal needle end (6) to pierce the distal membrane (24,34); and deforming the proximal membrane (14) to cause the tip of the proximal needle end (4) to pierce the proximal membrane (14).