GB2544278A

GB2544278A - Syringes and inserts for syringes

Info

Publication number: GB2544278A
Application number: GB1519802.1A
Authority: GB
Inventors: Shams Iden
Original assignee: Gbuk Group Ltd
Current assignee: Gbuk Group Ltd
Priority date: 2015-11-10
Filing date: 2015-11-10
Publication date: 2017-05-17
Anticipated expiration: 2035-11-10
Also published as: WO2017081467A1; GB201519802D0; GB2544278B

Abstract

A syringe 10 comprises a barrel 11; a plunger 12; and a tip 24; wherein the syringe further comprises an insert 13 which is located at least partially within the tip 24. The insert comprises a front 21 and rear 22 end and a channel 23 which extends therethrough. The insert 13 is retained in the tip 24 via an interference fit. The insert 13 may be dislodged via being pushed inwards, towards the barrel 11. The front end 21 of the insert 13 may have a tubular portion and the rear end 22 may have a tapered portion wider than the tubular portion. A syringe insert is also claimed.

Description

Syringes and Inserts for Syringes

Field of the Invention

The invention relates generally to syringes and inserts for syringes and has particular relevance in the field of syringes for small-dose enteral administration and inserts therefor.

Background to the Invention

Small bore connectivity in healthcare is the focus of much attention given the potential to misconnect intravenous, enteral and intrathecal administration lines. An erroneous connection between a syringe and an incorrect administration route can cause harm to or even death of a patient. This is particularly pertinent in neonatal healthcare where the incorrect administration of even a very small dose of medicine can have a catastrophic effect on the small body of a baby. Even where medicine is correctly administered, it is important for uptake and delivery of a medicine to be accurate due to the small volume of the doses concerned.

In neonatal healthcare in particular, it is common practice to administer very small doses of medication via the enteral route. Given that the standard syringe used for administration typically comprises a female fitting with a large internal bore, there are concerns with regard to the accuracy in delivery of small volumes (e.g. 50-1 ΟΟμΙ) of medication in light of the potential for the medication to occupy dead space within the bore of the female fitting. Inaccurate doses may be administered as a consequence.

There is a real need to provide means for improving the accuracy with which small doses of medicament are delivered to a patient, and for minimising the risk of or preventing incorrect administration through misconnection of a syringe.

Summary of the Invention

In a broad independent aspect, the invention provides a syringe comprising a barrel; a plunger which is, in use, at least partially located inside said barrel and moveable within it; and a tip; wherein the syringe further comprises an insert which, in use, is located at least partially within said tip, the insert comprising front and rear ends and a channel which extends therethrough; wherein the shape and size of the insert is such that the insert is retained in the tip via an interference fit.

This configuration is particularly advantageous because it provides a syringe with an insert which more accurately delivers the contents of the syringe for small doses of medicament when the syringe is actuated. The size of the channel of the insert, which is smaller in comparison to the internal diameter of the tip, minimises the amount of dead space in which a medicament can collect in use. This is particularly useful where a small dose of medicine is being administered because the medicine is less likely to collect in the tip of the syringe.

The interference fit minimises the risk of or prevents the misconnection of the syringe with an incorrect administration route.

Preferably, the retention of the insert is maintained unless said insert is pushed inwards by a force sufficient to overcome said interference fit. This configuration is particularly advantageous because the insert is dislodged if a force, sufficient to overcome the interference fit, is applied to the insert, i.e. the interference fit is overcome, if the insert is pushed inwards, towards the barrel. For example, where the tip comprises a female type connection, the interference fit minimises the risk of the syringe delivering the contents of the barrel if the syringe is connected to a female type connection of an incorrect administration route. If the insert is pushed inwards, towards the barrel, by, for instance, a female Luer connection of another administration route, the interference fit is overcome and the insert is dislodged and withdraws into the barrel of the syringe, rendering the syringe ineffective or unusable. This action minimises the risk that an operator will continue to use the syringe.

Preferably, the tip comprises a female connection fitting incorporating a bore and, in use, said insert extends at least partially into said bore. This configuration is particularly advantageous because, if an operator attempts to incorrectly attach a female type connection fitting to the tip, the insert is pushed towards the barrel to overcome the interference fit. As the insert extends at least partially into the bore of the female connection fitting, the interference fit is swiftly and reliably overcome where an incorrect connection is attempted. This configuration also improves the delivery of a medicine because the risk of the medicine accumulating in the bore of the fitting is minimised or prevented.

Preferably, the front end of said insert comprises a tubular potion and the rear end comprises a tapered portion; wherein each of the tubular and tapered portions has an inner and outer diameter; and wherein the diameter of said tapered portion at its widest point is greater than the diameter of said tubular portion. This configuration is particularly advantageous because it ensures that an effective and reliable interference fit is in place between the insert and the barrel.

Preferably, said interference fit is between the tapered portion of said insert and said barrel. This configuration is particularly advantageous because the interference fit between the tapered portion of the insert and the barrel forms a fluid-tight seal around the circumference of the insert, which is retained unless the insert is pushed towards the barrel.

Preferably, the outer diameter of at least part of said tubular portion increases in diameter towards said tapered portion. An increase in diameter of at least part of the tubular portion towards the tapered portion ensures an effective interference fit.

Preferably, the inner diameter of at least part of said tubular portion decreases in diameter towards said tapered portion.

Preferably, the inner diameter of at least part of said tapered portion decreases towards the inner diameter of said tubular portion. This configuration acts to funnel fluid initially contained in said barrel towards the tip.

Preferably, the outer diameter of at least part of said tapered portion decreases towards the outer diameter of said tubular portion. This configuration acts to improve the interference fit.

Preferably, said barrel and tip form a seat onto which the tapered portion of the insert sits in use. The seat which is formed improves the fluid-tight seal-forming interference fit between the barrel and insert. This configuration also prevents the insert from passing entirely through the tip.

Preferably, said interference fit is between said seat and the tapered portion of said insert. This configuration improves the fluid-tight seal between an outer surface of the insert and the barrel.

Preferably, the insert is comprised of a material which is more rigid than the material from which said barrel is comprised. The insert is comprised of a material which is more rigid than the material form which the barrel is comprised to ensure a sufficient degree of interference to generate the fit between the barrel and the tip.

Preferably, the diameter of said channel is wider towards the rear end of the insert than towards said front end. This configuration is particularly advantageous because it minimises the amount of dead space at the rear end of the insert where contents of the barrel may collect and not be delivered.

Preferably, the insert is formed of a single piece of plastics material. This configuration is particularly advantageous because the structural integrity of the insert is improved, thereby minimising the risk that the function of the insert will be impaired as stresses and strains typically expected with the use of syringes are applied. A single piece also minimises or prevents the risk of small parts passing through the tip and into an administration route which might cause serious harm to a patient.

In a second broad independent aspect, the invention provides a syringe tip insert, said insert comprising a tubular portion with an inner and an outer diameter; and a tapered portion at one extremity of said tubular portion with an inner and an outer diameter; a channel extending through both said tubular portion; wherein the outer diameter of at least part of said tubular portion increases in diameter towards said tapered portion.

This configuration is particularly advantageous because it provides a syringe tip insert which more accurately delivers the contents of a syringe when the syringe is actuated. The size of the channel of the insert, which is smaller in comparison to that of a syringe tip, minimises the amount of dead space in which a medicament can collect in use. This is particularly useful where a small dose of medicine is being administered.

The interference fit between the insert and a syringe minimises the risk of or prevents the misconnection of a syringe with an incorrect administration route. For example, where a syringe tip comprises a female type connection at its second end, the interference fit minimises the risk of the syringe delivering its contents if the syringe is connected to the female type connection of an incorrect administration route. If the insert is pushed towards the barrel of a syringe, by, for instance, a female Luer connection of another administration route, the interference fit is overcome and the insert retreats into the barrel of the syringe. This action minimises the risk that an operator will continue to use a syringe if misconnected. An increase in diameter of at least part of the tubular portion towards the tapered portion ensures an interference fit between the insert and the syringe.

Preferably, the inner diameter of said tapered portion decreases towards the inner diameter of said tubular portion.

Preferably, the outer diameter of said tapered portion decreases towards the outer diameter of said tubular portion. This configuration acts to improve the interference fit between the insert and the syringe.

Preferably, the insert is formed of a single piece of plastics material. This configuration is particularly advantageous because the structural integrity of the insert is improved, thereby minimising the risk that the function of the insert will be impaired as stresses and strains typically expected with the use of syringes are applied. A single piece also minimises or prevents the risk of small parts passing through the tip of a syringe and into an administration route which might cause serious harm to a patient.

Brief Description of the Drawings

In the drawings:

Figure 1A shows a schematic perspective view of a syringe of a preferred embodiment.

Figure 1B shows a cross-sectional side view of an insert of a preferred embodiment.

Figure 2 shows a cross-sectional side view of the syringe of Figure 1B.

Figure 3 shows a cross-sectional side view of a preferred embodiment of a syringe comprising a female connection fitting.

Figure 4A shows a perspective view of an insert of a preferred embodiment.

Figure 4B shows a perspective view of a syringe of a preferred embodiment.

Detailed Description of the Embodiments A preferred embodiment of a syringe is shown in Figure 1A and is referenced generally as 10. The syringe 10 comprises a barrel 11, a plunger 12, a tip 24 and an insert 13, which forms an interference fit with the barrel 11, and functions to improve the accuracy with which medicaments are delivered by minimising dead space at the fluid exit point of the syringe 10, whilst minimising the risk that the syringe 10 is misconnected to an erroneous administration route.

The barrel 11, which has at least one outer surface and at least one inner surface comprising a receptacle for a medicament, further comprises a first end 14 and a second end 15 and a chamber 25. The first end 14 is the end which is typically held by an operator during use and incorporates one or more flanges 16 which, in use, are held by the hand of an operator as pressure is applied to a top end 17 of the plunger 12. The syringe 10 comprises a tip 24 at the second end 15 of the barrel 11. In use, medicine is expelled from the barrel 11 via the tip 24 as pressure is applied to the plunger 12. As pressure is applied to the top end 17 of the plunger, a projection 18 is pushed further inside the barrel 11 to displace the contained fluid. The plunger 12 further comprises a seal 19 at a distal end 20 of the projection 18 to prevent fluid from travelling towards the first end 14 of the barrel 11 as the plunger 12 is pushed towards the second end 15.

The first end 14 of the barrel 11 incorporates an opening for receiving the projection 18 of the plunger.

The tip 24 may comprise a connection fitting 26, such as a female screw-type fitting to facilitate attachment of the syringe 10 to an administration route, such as enteral tubing leading to the stomach of a patient. The fitting 26 comprises a bore 27 (see Figure 3) which is in fluid connection with the barrel 11. In a preferred embodiment, the barrel 11 and tip 24 are integrally formed, but in an alternative embodiment the tip 24 is a separate component which is attached to the barrel 11 prior to use.

The insert 13, which is shown more clearly in Figure 1B, comprises a front end 21 and a rear end 22 and a channel or passage 23 which extends therethrough. In use, the insert 13 is positioned within the syringe 10 such that it is held and extends through the tip 24. An interference, press or friction fit is achieved between the barrel 11 and insert 13. In one embodiment, an additional interference fit may be in place between the insert 13 and at least part of the tip 24. Once the insert 13 is inserted and retained by the interference fit, the front end 21 of the insert 13 is preferably located beyond the tip 24, i.e. the front end 21 is located in the bore of the fitting 26. The size and shape of the insert 13 is such that the insert 13 forms an interference fit (press fit, friction fit, or fluid tight junction) with an inner surface of the barrel 11. A seat 28 or shoulders are formed within the barrel 11 by the reduction in diameter between the barrel 11 and the tip 24. In a preferred embodiment, the interference fit is between the insert 13 and the seat 28 or shoulders of the barrel 11.

The smaller diameter of the channel 23 of the insert 13 compared to the inner diameter of the tip 24 improves the accuracy of delivery of small doses of medicines because the space in which fluid may collect and subsequently fail to be dispersed from the syringe 10, as an operator applies pressure to the plunger 12 is reduced or eliminated.

In use, if the insert 13 is pushed towards the barrel 11, i.e. towards the first end of the barrel 11, with a force sufficient to overcome the interference fit between the barrel 11 and the insert 13, the insert 13 retreats into the barrel 11 of the syringe 10 to prevent misconnection of the syringe 10 with an erroneous administration route. For example, where an operator attempts to connect a female type connector to the syringe 10 and insert 13, the motion of pushing the connector onto the insert 13 will cause the interference fit between the insert 13 and barrel 11 to be broken and the insert 13 will subsequently retreat into the barrel 11. In a preferred embodiment, the interference fit between the insert 13 and the barrel 11 is sufficient to prevent dislodging of the insert 13 unless the insert 13 is specifically pressed towards the first end 14 of the barrel 11. This allows an operator to use the syringe 10 with confidence, knowing that the interference fit will only be broken if an incorrect connection with another administration route is attempted.

Figure 2 shows a cross-sectional view from the side of the syringe 10 to show, in more detail, the difference in inner diameter of the barrel 11 and tip 24 and how the channel 23 of the insert 13 further reduces in diameter to improve the accuracy with which medicines can be delivered.

Best shown in Figure 3, a seat 28 is formed by the change in inner diameter of the barrel 11 and the tip 24.

The front end 21 of the insert 13 comprises a tubular portion and the rear end 22 of the insert 13 comprises a tapered portion. In a preferred embodiment, the tapered portion, in use, abuts against the seat to form the interference fit, to stabilise the insert 13 and to prevent it from passing entirely through the tip 24. In a further preferred embodiment, the insert 13 is tapered towards the front end 21 to ensure that, as the insert 13 contacts the inner surface of the barrel 11, there is sufficient friction between the insert 13 and barrel 11 to establish the interference fit (in preferred embodiment a fluid tight junction) between the two components. In one embodiment, the rear end 22 of insert 13 comprises a portion of increased diameter and the tapering of the insert is stepped. However, tapering of the insert 13 may alternatively be consistent from the rear end 22 towards the front end 21. In another alternative embodiment, the insert 13 is tapered over a plurality of stepped portions towards the front end 21.

In a preferred embodiment, the tubular and tapered portions each has an inner and outer diameter, wherein the diameter of the tapered portion at its widest point is greater than the diameter of the tubular portion. Preferably, the outer diameter of at least part of, and more preferably all of, the tubular portion increases in diameter towards the tapered portion. In a further preferred embodiment, the inner diameter of at least part of, and more preferably all of, the tubular portion decreases in diameter towards the tapered portion. In a yet further preferred embodiment, the inner diameter of at least part of, and more preferably all of, the tapered portion decreases towards the inner diameter of the tubular portion. In a still further preferred embodiment, the outer diameter of at least part of, and more preferably all of, the tapered portion decreases towards the outer diameter of the tubular portion.

In a preferred embodiment, the outer diameter of the tubular portion of the insert 13 tapers such that the syringe 10 is incompatible with a female Luer connector, i.e. it is not a 6% taper. In preferred embodiment, the taper of the outer diameter of the tubular portion is between 1% and 4% and preferably the taper is 2%.

In a preferred embodiment, the diameter and taper of the bore of the tip 24 is such that the tip 24 is incompatible with a male Luer connector. This is because the diameter of the bore of the tip 24 is much larger than the diameter of a male Luer connector.

In a preferred embodiment, the diameter of the channel 23 of the insert 13 is wider towards the rear end 22 of the insert 13 than towards the front end 21. The wider diameter towards the rear end 22 improves the ability of the insert 13 to channel fluid from the barrel 11 out of the syringe 10 because the opportunity for fluid to collect around the rear end 22 of the insert 13 and not flow through the channel 23 is minimised.

In a preferred embodiment, where the tip 24 incorporates a fitting 26 and the insert 13 extends at least partially into the bore 27 of the fitting 26 once an interference fit is established between the barrel 11 and the insert 13. In a further preferred embodiment, which is shown in Figure 3, the insert 13 does not extend beyond the rim of the fitting 26 to minimise the risk that the insert 13 is knocked or pushed from the side, which might dislodge the insert 13 during normal, correct use.

In a preferred embodiment, the insert 13 is comprised of a material which is more rigid than the material from which the barrel 11 is comprised. The barrel 11 is preferably comprised polypropylene and the insert 13 is therefore preferably comprised of a material which is more rigid than polypropylene or is comprised of polypropylene which is more rigid than the polypropylene of the barrel 11. Preferably, the insert 13 is formed of a single piece of plastics material. In an alternative embodiment, at least a portion of the insert 13 is comprised of a material which is more flexible than the material of the barrel.

In a preferred embodiment, the insert 13 is preferably removably inserted in said barrel 11 so that the insert 13 may be used with different syringes. The may be provided as part of a kit with the syringe 10 as shown in Figures 1A, 2 and 4B. In an alternative, broad, embodiment, the insert 13 is provided on its own, i.e. without the syringe 10, as shown in Figures 1B and 4A. In this embodiment, the insert 13 forms an interference fit with a portion of a barrel, preferably of reduced diameter, of a separate syringe.

Claims

1. A syringe comprising a barrel; a plunger which is, in use, at least partially located inside said barrel and moveable within it; and a tip; wherein the syringe further comprises an insert which, in use, is located at least partially within said tip, the insert comprising front and rear ends and a channel which extends therethrough; wherein the shape and size of the insert is such that the insert is retained in the tip via an interference fit.

2. A syringe according to claim 1, wherein the retention of the insert is maintained unless said insert is pushed inwards by a force sufficient to overcome said interference fit.

3. A syringe according to either claim 1 or claim 2, wherein the tip comprises a female connection fitting incorporating a bore and, in use, said insert extends at least partially into said bore.

4. A syringe according to any of the preceding claims, wherein the front end of said insert comprises a tubular potion and the rear end comprises a tapered portion; wherein each of the tubular and tapered portions has an inner and outer diameter; and wherein the diameter of said tapered portion at its widest point is greater than the diameter of said tubular portion.

5. A syringe according to claim 4, wherein said interference fit is between the tapered portion of said insert and said barrel.

6. A syringe according to either claim 4 or claim 5, wherein the outer diameter of at least part of said tubular portion increases in diameter towards said tapered portion.

7. A syringe according to any of claims 4 to 6, wherein the inner diameter of at least part of said tubular portion decreases in diameter towards said tapered portion.

8. A syringe according to any of claims 4 to 7, wherein the inner diameter of at least part of said tapered portion decreases towards the inner diameter of said tubular portion.

9. A syringe according to any of claims 4 to 8, wherein the outer diameter of at least part of said tapered portion decreases towards the outer diameter of said tubular portion.

10. A syringe according to any of claims 4 to 9, wherein said barrel and tip form a seat onto which the tapered portion of the insert sits in use.

11. A syringe according to claim 10, wherein said interference fit is between said seat and the tapered portion of said insert.

12. A syringe according to any of the preceding claims, wherein the insert is comprised of a material which is more rigid than the material from which said barrel is comprised.

13. A syringe according to any of the preceding claims, wherein the diameter of said channel is wider towards the rear end of the insert than towards said front end.

14. A syringe according to any of the preceding claims, wherein the insert is formed of a single piece of plastics material.

15. A syringe substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.

16. A syringe tip insert, said insert comprising a tubular portion with an inner and an outer diameter; and a tapered portion at one extremity of said tubular portion with an inner and an outer diameter; a channel extending through both said tubular portion and said tapered portion; wherein the outer diameter of at least part of said tubular portion increases in diameter towards said tapered portion.

17. An insert according to claim 16, wherein the inner diameter of at least part of said tubular portion decreases in diameter towards said tapered portion.

18. An insert according to either claim 16 or claim 17, wherein the inner diameter of said tapered portion decreases towards the inner diameter of said tubular portion.

19. An insert according to any of claims 16 to 18, wherein the outer diameter of said tapered portion decreases towards the outer diameter of said tubular portion.

20. An insert according to any of claims 16 to 19, wherein the insert is formed of a single piece of plastics material.

21. An insert substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.