WO2012120296A1

WO2012120296A1 - Injection device

Info

Publication number: WO2012120296A1
Application number: PCT/GB2012/050499
Authority: WO
Inventors: Alina MIHAI
Original assignee: Coventry University
Priority date: 2011-03-09
Filing date: 2012-03-07
Publication date: 2012-09-13
Also published as: GB201104047D0

Abstract

A single use, disposable injection device (1, 12) comprises a tube (4) terminating at one end in an outlet, and a flexible bag (2) connected to the other end of the tube and containing a liquid (3) to be injected, such as a dose of a pharmaceutical substance. The tube may be in the form of a hypodermic needle (18) or be attached to such a needle (5). The flexible bag is sealed within an outer flexible container(6), with the space between the container and the bag being filled with a liquid (7) so that compression of the outer container causes hydraulic pressure to be exerted on the inner bag to compress the bag and inject the contents of the bag into a patient. A non-return valve (11) may be provided. The liquid between the bag and the outer container is sterile and non-toxic, such as saline solution. A device (20) may be provided to sever and retain the needle after use.

Description

Injection Device

The present invention relates to an injection device for injecting fluid into a cavity or a part of the human or animal body. The invention is particularly, but not exclusively, concerned with an injection device for use with a hypodermic needle that will penetrate the skin of a patient.

Conventionally, injections are made using a syringe which consists of a cylindrical reservoir, an outlet connected to a hypodermic needle, and a piston within the reservoir attached to a plunger. The reservoir may be pre-filled with the liquid to be injected, or the liquid may be sucked into the reservoir before injection. It has been proposed to provide an injection device in which, instead of a cylindrical reservoir and plunger arrangement, the device has a bag made of a flexible material, the bag being pre-filled with the liquid to be injected. By squeezing the bag, the liquid contained will be passed down a tube to an outlet.

According to one aspect of the present invention, there is provided an injection device comprising a tube terminating at one end in an outlet, and a flexible bag connected to the other end of the tube and containing a liquid to be injected, whereby upon compressing the bag the liquid contained is caused to flow along the tube to the outlet, characterised in that the flexible bag is sealed within an outer flexible container with the space between the container and the bag being filled with a fluid so that compression of the outer container causes pressure to be exerted on the inner bag so as to compress the bag.

Preferably, the fluid is a liquid and thus according to another aspect of the present invention, there is provided an injection device comprising a tube terminating at one end in an outlet, and a flexible bag connected to the other end of the tube and containing a liquid to be injected, whereby upon compressing the bag the liquid contained is caused to flow along the tube to the outlet, characterised in that the flexible bag is sealed within an outer flexible container with the space between the container and the bag being filled with a liquid so that compression of the outer container causes hydraulic pressure to be exerted on the inner bag so as to compress the bag. The hydraulic pressure created by compression of the outer container is applied evenly around the bag so as to ensure that all, or at least a known part, of the contents pass from the bag and into the tube. Where the bag is pre-filled with the liquid to be injected, such as a medication, this ensures that a properly measured dose is injected. The arrangement is more consistent and easier to use than one in which the bag containing the liquid to be injected is compressed directly.

There have been proposed arrangements in which a mechanical device is provided to squeeze a bag containing the liquid to be injected, but this adds to the bulkiness, weight and complexity of the arrangement. The mechanical device may be reusable but it will be necessary to locate it before administering the injection. It will also be an additional device that needs to be sterilised.

The device in accordance with the invention can be fully disposable. After use the outer container and the inner bag will occupy a relatively small space. Neither the inner bag nor the outer container will contain air, and apart from the thickness of the materials of the bag and container there will be the volume of the liquid between them. Typically the used device will be flat and perhaps around 5 mm or less thick.

The device can be supplied with a hypodermic needle attached, or can be attached to such a needle before use. Where the device is provided with a hypodermic needle attached, the needle itself may constitute the tube, or there may be a separate tube to which the needle is connected. The needle is preferably attached permanently to the device so that it can only be removed by being broken.

A non-return valve may be provided to ensure that liquid may only flow out of the bag and to prevent air being sucked into the bag.

The outer container may be provided with a pad or the like on which a user's finger or thumb can be located, to ensure that device is held in the correct manner. For example, the wrist can be kept at a neutral position if the angle of a pad or grip indicating where to press is correct.

In some embodiments the liquid between the outer container and the inner bag is non-toxic and sterile so that if there is failure of the wall of the bag and liquid contaminates the liquid to be injected, there will be no ill effects on the patient. For example, the liquid could be sterilised water or a sterile saline solution. Preferably the space between the outer container and inner bag contains no gas such as air, so that there is no risk of the gas entering the inner bag in the event of a failure. The inner bag will contain only the liquid to be injected, and no gas such as air.

The liquid in the space between the outer container and inner bag could be used to clean or sterilise the hands of a user after the device has been used, if the liquid is suitable and there is means to access it - such as a sealed opening. A disinfectant liquid or gel may be used.

In general the term "liquid" used in relation to the material in the space between the outer container and inner bag, encompasses gels and the like which are capable of transmitting hydraulic pressure.

The device is intended to be supplied pre-filled with a pharmaceutical substance to be administered. This reduces the risk of dosing errors, and reduces the risk of air embolisms. The device is intended for single use, thus avoiding the problems associated with reuse, such as infections. The device is easy to use, saves time, and little training will be required. The outer container may be of a material that is easy to grip and is non-slip.

The device may be used by medical staff such as doctors or nurses, or may be used by patients themselves if there is a requirement for self medication such as injecting insulin.

The inner bag and outer container may be of medical grade polypropylene or another suitable medical grade material that will provide the required characteristics such as clarity, heat resistance, impact resistance, flexibility, durability and inertness so that there can be no tainting of the liquid to be injected.

In one embodiment of the invention, the inner bag and the outer flexible container are attached to an externally projecting support, through which passes a hypodermic needle so as to project into the inner bag. A removable needle cap may be provided which can be attached to the support and removed when the device is to be used, for example by being snapped from the support.

An advantage of devices in accordance with the invention is that they can prevent re-use of needles - thus reducing the risk of cross infection associated with syringe/needle re-use.

In an effort to reduce accidental injury from discarded devices - particularly in the case of poorly managed clinical waste, preferably devices are distributed with apparatus that disables the needles after use, for example by breaking and separating the needle from the injection device. Preferably such apparatus includes or is provided with means which will capture the clinical waste in a safe, organised manner, thus helping to promote and raise awareness of best practice.

In one embodiment, the device is provided with a mechanism for removing and storing the needle after the device has been used. This can comprise an elongate, open topped receptacle of plastic or the like, attached by a hinge to the device. The mechanism cam be moved away from the needle when the device is to be used, and then moved into contact with the needle after use. The receptacle contains a sharp portion, for example of metal which can snap the needle, preferably adjacent to where it projects from the device, when the receptacle is pushed into

engagement with the needle. The receptacle preferably contains gripping portions between which the needle is gripped. With the needle safely within the receptacle and the device now incapable of use, the device together with the receptacle and needle can now be disposed of.

A device in accordance with the invention is particularly suitable in developing countries for vaccinations, mass vaccinations, and emergency inoculations, for people that are not really trained. The preferred device serves the purpose of a disposable syringe with a disposable needle. In preferred arrangements the device will come always pre-filled and will save people a time by not having to draw into a syringe the substance to be administered. This will also infection control issues associated with drawing up drugs into a syringe. The volume of substance in the inner bag to be administered may be chosen to be suitable for inoculations and may for example be no more than about 1 ml. The dimensions of the device are preferably compact to increase ease of use and for example to make the device more suitable for right and left hand use.

The needle used with the device may be identified by colour coding, for example by adhering to an internationally recognised colour-coding system to identify the needle size. For example, a blue or green colour may be used according to the size of the person. The needle may be used at 90 degrees to the skin of the patient.

By making the device non-refillable and the needle non-removable, a doctor or other user will be prevented from using the device repeatedly on other patients.

The device may be disposed after use in a "sharp safe" biohazard box, of the type already in use now in hospitals and clinics.

The use of a hydraulic mechanism, for example using a saline liquid in the outer container, protects the patient if there is puncture of the inner bag.

The small quantity of liquid necessary to dispense the dose of medication , which dose typically will be no more than about 1 ml, means that the cost of the device is not excessive.

If it is necessary the device can contain a non-return valve, which will show if the nurse or other person using the device has hit a blood vessel.

All the body of the device will have a low opacity so that the substance to be administered can be seen.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying schematic drawings, in which:

Figure 1 is a plan view of an embodiment of the invention;

Figure 2 corresponds to Figure 1 but with optional components included;

Figure 3 is a side view of the embodiment of the invention, before use; Figure 4 is a side view of the embodiment of the invention, after use;

Figure 5 is a side view of a second embodiment of the invention;

Figure 6 is a side view of a modification of this second embodiment, modified soas to have a needle disposal mechanism; and

Figure 7 is a detailed view of the needle disposal mechanism.

Referring now to the figures in more detail, the injection device 1 shown in Figure 1 comprises an inner flexible bag 2, containing a liquid 3 to be injected. The bag 2 communicates with one end of a tube 4 and a hypodermic needle 5 is connected to the other end of the tube 4. The bag 2 is sealed within an outer flexible container 6 and the space 7 between the inner bag 2 and the outer container 6 is filled by a liquid 7, such as sterile saline solution.

As shown in Figure 2, the outer container 6 is provided with a pad 8 indicating where a user is to press the container. An outer protective sheath 9 is provided around the tube 4, and a removable protective cap 10 is provided around the hypodermic needle 5. The end of the tube 4 is provided with a non-return valve 1 1 .

Before use, the bag 2 is full of the substance 3 to be injected, as shown in Figure 3. The outer container 6 is then compressed so that the liquid 7 exerts hydraulic pressure around the bag 2. The contents 3 are then ejected down the tube and through the hypodermic needle 5. The device then reaches the condition shown in Figure 4. The contents of the bag 2 have been expelled and the bag has collapsed, but the liquid 7 between the outer container 6 and the bag 2 remain in place. The flattened device 1 can then be disposed of, and takes up less space than the filled device shown in Figure 3.

Referring to Figure 5, an injection device 12 comprises an inner flexible bag 13, containing a liquid 14 to be injected.. The bag 13 is sealed within an outer flexible container 15 and the space 16 between the inner bag 13 and the outer container 15 is filled by a liquid 7, such as sterile saline solution. The outer container 15 is provided with an externally projecting support 17 and a tubular hypodermic needle 18 passes through this support and into the inner bag 13. The hypodermic needle 18 is sealed in the support 17 and the bag 13 is sealed around the open end of the needle 18 so that there is no leakage of the liquid 16 or risk of the liquid 16 contaminating the liquid 14 to be injected. The bag 13 may also be sealed to the outer container 15 and optionally the support 17, in the region where the hypodermic needle 18 enters the bag. The needle 18 is provided with a removable protective sheath or cap 19.

Figure 6 shows a modification of this embodiment a receptacle 20 for the needle 18 is attached by a hinge portion 21 to the support 17, so that it can be moved in the directions of the arrows A and B. The receptacle is semi-tubular having an open top facing the needle 18 and an elongate interior 22.. As shown in Figure 7, within the receptacle 20 is provided a sharp part 23 for snapping a needle, for example of metal or hard plastic. By moving the receptacle 20 in the direction of the arrow B, the needle can be snapped adjacent to where it enters the support 17. The receptacle 20 is provided with resilient portions 23 of plastic which grip the snapped off needle. The disabled device, with the snapped off needle attached, can then be disposed of safely.

The use of a receptacle to remove (i.e. disable) and retain a needle is

advantageous with a variety of syringe devices, whether the device in accordance with the present invention or otherwise. Thus, in accordance with another invention disclosed herein there is provided a device for removing and retaining a hypodermic needle comprising an elongate receptacle with an open top which contains a severing portion to snap a hypodermic needle when pressure is exerted between the device and the needle, and means for retaining the severed needle in the receptacle. There may be projections at spaced intervals in the receptacle, between which a detached needle can be gripped. The receptacle may be attached in movable fashion to an injection device. The device may comprise two halves which are clamped around a needle, to provide the force to snap the needle with is then retained inside the closed receptacle.

In a modification of the injection device as described above, the space between the outer container and the inner bag could be filled with a gas, such as air or nitrogen. The outer container could be generally self supporting but capable of compression. Transfer of pressure to the inner bag would be by pneumatic force rather than hydraulic. In other respects the device could be identical to the embodiments of the invention described above and all optional features of the device described and claimed which uses hydraulic pressure, which are compatible with the use of pneumatic pressure, apply equally to a device using a gas instead of a liquid.

Claims

1 . An injection device comprising a tube terminating at one end in an outlet, and a flexible bag connected to the other end of the tube and containing a liquid to be injected, whereby upon compressing the bag the liquid contained is caused to flow along the tube to the outlet, characterised in that the flexible bag is sealed within an outer flexible container with the space between the container and the inner bag being filled with a fluid so that compression of the outer container causes pressure to be exerted on the inner bag so as to compress the inner bag.

2. An injection device as claimed in claim 1 , wherein the tube is a tubular portion and at said one end of the tube there is means for attaching the tube to a hypodermic needle.

3. An injection device as claimed in claim 1 , wherein the tube is a hypodermic needle.

4. An injection device as claimed in claim 3, wherein the outer container is provided with a support through which the hypodermic needle passes in sealing fashion, the hypodermic needle opening into the inner bag.

5. An injection device as claimed in claim 1 , wherein the tube is a tubular portion and at said one end of a hypodermic needle is attached to the tube.

6. An injection device as claimed in claim 3, 4 or 5, wherein the needle is attached non-releasably to the remainder of the device.

7. An injection device as claimed in any preceding claim wherein the liquid to be dispensed is a dose of a pharmaceutical substance to be administered to a patient.

8. An injection device as claimed in claim 6, wherein the device is a disposable single-use device.

9. An injection device as claimed in any preceding claim, wherein a non-return valve is provided to ensure that liquid may only flow out of the bag and to prevent air being sucked into the bag.

10. An injection device as claimed in any preceding claim, wherein the outer container is provided with a pad on which a user's finger or thumb can be located.

1 1 . An injection device as claimed in any preceding claim, wherein there is provided a device for removing and retaining a hypodermic needle after use.

12. An injection device as claimed in claim 1 1 , wherein the device for removing and retaining a hypodermic needle comprises an elongate receptacle with an open top which contains a severing portion to snap the hypodermic needle when pressure is exerted between the device and the needle, and means for retaining the severed needle in the receptacle.

13. An injection device as claimed in claim 12, wherein there are projections at spaced intervals in the receptacle, between which a detached needle can be gripped.

14. An injection device as claimed in claim 1 1 , 12 or 13, wherein the device for removing and retaining a hypodermic is attached in movable fashion to the injection device.

15. An injection device as claimed in any preceding claim, wherein the fluid in the space between the container and the inner bag is a liquid so that so

compression of the outer container causes hydraulic pressure to be exerted on the inner bag so as to compress the bag.

16. An injection device as claimed in claim 15, wherein the liquid between the outer container and the inner bag is non-toxic and sterile.

17. An injection device as claimed in claim 16, wherein the liquid between the outer container and the inner bag is sterile saline solution.