GB2462669A

GB2462669A - A syringe element for a needle-free injection apparatus

Info

Publication number: GB2462669A
Application number: GB0814622A
Authority: GB
Inventors: David Murray Macdonald
Original assignee: MANAGED TECHNOLOGIES Ltd
Current assignee: MANAGED TECHNOLOGIES Ltd
Priority date: 2008-08-11
Filing date: 2008-08-11
Publication date: 2010-02-24
Anticipated expiration: 2028-08-11
Also published as: GB0814622D0; GB2462669B

Abstract

A syringe element 1 for a needle-free injection apparatus. The syringe element 1 comprises a cylindrical body 2 having a first end and a second end. The syringe element 1 provides a bore 9 of a first diameter and a stub 3 provides a bore 7 of a second diameter. The stub extends from the second end of the cylindrical body 2 and the bore 7 extends through the stub 3 and is in fluid communication with the inside of the cylindrical body 2. The ratio of the length of said bore 7 to its diameter is at least 140:1 (which corresponds to a length of 7mm and a width of 50 microns). Also disclosed is a syringe element 1 where the stub 2 includes a sealing element 5, which closes off the bore 7, is detachable from the stub 3 and is made from the same material as said stub 3. The syringe element 1 can also be incorporated into a drug administration device comprising at least one syringe element holder, and an actuator.

Description

NEEDLE-FREE INJECTION APPARATUS AND METHOD

Field of the Invention

The present invention relates to a needle-free injection apparatus, and in particular to a single dose needle-free injection apparatus.

Background of the Invention

Administration of drugs to the intra-muscular or sub-dermal regions of the body (human or animal) usually involves the use of a hypodermic needle. Hypodermic needles present a number of problems.

Whilst in principle, at least in human health care, hypodermic needles should be used once and disposed of, this does not always happen. Needles which are thought to have been disposed of safely may find their way to drug users, where diseases such as hepatitis and HIV/AIDS may be spread.

Further, hypodermic needles require a syringe. In order to prevent any possibility of cross-contamination of patients being injected with a hypodermic needle, not only should the needle be discarded after each injection, but the syringe should also be discarded.

Hypodermic needles and syringes do not appear to be particularly costly as individual items.

However, where a syringe is to be supplied pre-filled with the needle attached the current cost would be in excess of forty pence per unit. If a mass immunization program is planned, possibly * vaccinating millions of individuals, the cost of hypodermic needles and syringes required may be S... * . r

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Where the syringe is not supplied pre-filled the substance must be drawn into the syringe ** through the needle. This may be done either by inserting the needle to be used into a bottle

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containing the desired substance, and then withdrawing the substance by extending the plunger of the syringe, or by carrying out the same procedure but using a hypodermic needle dedicated to the bottle, detaching the filled syringe from the needle dedicated to the bottle and attaching a fresh sterile needle, prior to injecting the substance. This is a time consuming activity with significant possibilities for errors resulting in cross-contamination.

When filling the syringe with a drug to be injected, the syringe should be filled such that the amount of drug administered corresponds to the weight of the person to whom the drug is to be administered. It is a health professional who fills the syringe. There is obvious scope for human error in the filling of the syringe. Such errors can prove fatal.

Still further, qualified health professionals are required to administer drugs using a hypodermic needle and syringe. This is because in many instances the needle must be inserted into the correct part of the body to a correct depth. Poor insertion of the needle may result in pain being experienced by the patient, and no or ill effects from the injected drug.

Yet another problem associated with hypodermic needles is the possibility of cross-infection resulting from the person administrating the drug mistakenly self-injecting after administering a drug to a patient.

Yet another problem associated with hypodermic needles is that being very sharp objects they may be used as weapons and therefore, in the context of healthcare provision, represent a danger to health professionals dealing with dangerous patients.

Another problem associated with hypodermic needles is the damage that they cause to the skin. * . S... * *. * . . * ..

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Needle free injection systems are known. They are used predominantly where there is a requirement to administer drugs frequendy for a long period of time, the largest single group of individuals using needle free injection systems being people suffering from diabetes.

Needle free injection prevents the possibility of disease transmission through the use of a single hypodermic needle for more than one person. However, the drug delivery systems for needle free injection devices tend to be complex.

One example of a needle free injection system is described in W02006/012151. This provides a delivery pressure of 3000 to 3500psi, and injects fluid subcutaneously through two jet nozzles.

Another example of a needle free injection system is described in US2007191762. In this system the drug is contained in an ampule formed of plastics material. The plastics material of the ampule deforms under the pressure rise caused by depressing the plunger, leading to pressure in the fluid dropping, reducing the efficiency of injection.

WO 2008/023300 describes a drug delivery device powered by a piezoelectric actuator, the amount of drug delivered corresponding to an inputted weight of a patient.

Whilst attempts have been made to commercialise needle free injection systems, use of such systems has not been taken up widely owing to technical problems and cost penalties.

It would therefore be desirable to provide an improved apparatus and method for administering drugs normally dispensed by injection. * ** * S * * **

". Summary of the Invention *S..

* * . * According to one aspect of the invention there is provided a syringe element for a needle-I..

* free injection apparatus as specified in Claim 1.

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S. S 3 S * S S *S According to another aspect of the invention there is provided an administration device as specified in Claim 11.

According to another aspect of the invention there is provided a method of injecting as specified in Claim 15.

Brief Description of the Drawings

In the drawings which illustrate a preferred embodiment of a needle-free injection apparatus, and are byway of example: Figure 1 is a schematic representation of a syringe element forming part of the apparatus of the invention; Figure 2 is a cross-sectional elevation of the syringe element illustrated in Figure 1; and Figure 3 is a cross-sectional elevation of the syringe element illustrated in Figures 1 and 2 mounted in a delivery device; Figure 4 is a schematic representation of an alternative delivery device.

Figure 5 is a schematic representation of the delivery device illustrated in Figure 4.

Detailed Description of the Preferred Embodiments

Referring now to Figure 1, a syringe element 1 comprises a cylindrical body 2 having first and second ends. The first end is substantially open, whereas the second end is closed and mounts a stub 3 having a length of about 10mm. A bore 7 extends through a first portion 4 of the stub 3 and I..

* is in fluid communication with the inside of the cylindrical body 2. The cylindrical body 2 is formed from a thin glass wall, and typically has an internal diameter of about 8 mm. The stub 3 comprises a *** substantially solid piece of glass and typically has an external diameter of about 4mm. The bore 7 **S..S * * ** * 4 * * ** extending through the first portion 4 of the stub 3 typically has a diameter of between 20 and 50 microns, the actual diameter being selected according to inter a/ia the density and viscosity of the fluid to be ejected from the cylindrical body 2 through the bore 7. Advantageously, the stub 3 is formed from a piece of capillary tube.

The end of the stub 3 is fused to form first and second portions in the stub 3. The first portion 4 includes the aforesaid bore. In the second portion 5, the bore is sealed, thereby preventing egress of fluid from the syringe element 1. The outer surface of the stub 3 includes a groove 6 which provides a frangible connection between the first and second portions of the stub 3.

One of the important features of the present invention is the length to diameter ratio of the bore 7. As mentioned above, the diameter of the bore 7 is in the order of 20 and 50 microns. The length of the bore is in the order of 6 mm. The combination of the length of the bore 7 to its diameter and the pressure to which the liquid in the cylindrical body is subjected results in fluid exiting the end of the bore at very high velocity and being subjected to a hydraulic flip, which means that the fluid is ejected as a continuous stream in the form of a very fine jet, rather than being atomised, as happens when the length to diameter ratio is reduced. By providing a continuous stream, dispersion of the fluid between the needle end and the skin surface is reduced.

The liquid exits the bore at high velocity due to the difference in cross-sectional areas of the cylindrical body 2 and the bore 7. The continuity equation states that Alvi = A2v2, where A is the cross-sectional area and v is the fluid velocity at points 1 and 2, which implies that any reduction in cross-sectional area of a conduit must be compensated by an increase in velocity. * **

* .*. Where the internal diameter of the cylindrical body 2 is 8mm and the internal diameter of *I** * the bore 7 is 50 micron, following the equation A izr2, where A is the cross-sectional area and r is * the radius, the respective cross-sectional areas of the cylindrical body 2 and the bore 7 are as follows:

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Cylindrical body 2: Cross-section area 3.14 x 4mm x 4mm = 50.24mm2; Bore 7: Cross-sectional area 3.14 x 0.025mm x 0.025mm 0.0019625 mm2.

The area of the Bore 7 is 25600 times smaller than the area of the cylindrical body 2, hence the velocity of fluid passing through the bore 7 is 25600 times greater than the velocity of travel of the stopper 8.

A self-sealing two part syringe closure comprises a stopper 8 and a plug 10. The stopper 8 is located within the cylindrical body 2, in the example the stopper being formed from a suitable sterile polymer. A bore 9 having a diameter of between 0.5 and 1.0mm extends axially through the stopper 8 and receives a shaft part 12 of a plug 10. The plug 10 comprises a head 11 and the afore-mentioned shaft 12. The external diameter of the shaft 12 is marginally greater than the internal diameter of the stopper, which is itself deformable.

The manner of operation of the syringe element I will now be described below; Filling: A substance to be administered is introduced into the cylindrical body 2.

The stopper 8 is inserted into the cytindrical body 2 and is pressed down, for example by means of a plunger 15 (see Figure 3), until all liquid contained within the cylindrical body 2 is expelled via the bore 9. The plug 10 is then introduced into the cyhndrical body 2, the shaft 12 * * * thereof being aligned with the bore 9 of the stopper 8, and the shaft 12 is pressed into the said bore 9 * : by exerting a force on the head 11. 0** *

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The filled syringe element is then packaged in suitable packaging, for example sterile packaging, and dispatched for use.

Using: In order to eject fluid from the syringe element 1, the syringe element is loaded into a suitable delivery device, for example that shown in Figure 3, or Figures 4 and 5. The second portion of the stub 3 is removed. A user of the syringe element I does this by snapping off the said second portion 5, typically using his fingers. An actuator of some description is brought up to the free surface of the head 11 of the plug 10. As the actuator exerts a force on the head 11 in the direction of the stub 3, the shaft 12 of the plug 10 is pressed into the stopper 8. That the external diameter of the shaft 12 is greater than the internal diameter of the bore 9 causes the plug 8 to increase in diameter, thereby causing the outer surface of the plug to form a fluid tight seal with the inside wall of the cylindrical body 2.

The open tip of the tube is held a short distance away from the surface of the skin of the person or animal to whom the drug is to be administered. Fluid exiting the bore 7 passes through the skin into the body.

Referring now to Figures 3 and 4, a device 20 for delivering a liquid contained in a syringe element of the type described above comprises a body 21 having an upper end 22 configured to receive and attach to a cap 23, for example the inner surface of the cap 23 and the outer surface of the end 22 may be provided with corresponding threads. The cap 23 provides a housing 24 which is configured to mount a button 25, which is biased into an "oft" position by a spring 26. The housing

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24 also receives a switch element 29 of an electrical power device 28 which is configured to power a *5SS solenoid 30. The switch element 29 is aligned with a shaft 27 of button 25. When the button 25 is depressed the switch element 29 is switched to on, and the electrical power device 28 powers the * 55 solenoid 30.

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Attached to the base of the body 20 is a carousel 30 which is mounted to rotate about a shaft 31. The shaft 31 extends between a recess 32 in the underside of the body 21 and a recess 35 located in an arm 33 which is pivotally attached to the body 21 by a hinge 34.

The carousel 30 includes individual openings to receive a number of syringe elements (for example 6) of the type described with reference to Figures 1 and 2 for example. To use the device 20 the carousel is moved to a position in which a syringe element is aligned axially with the shaft 36 of the solenoid 30. The solenoid shaft 36 engages with the plug 10, forcing the shaft 12 thereof into the bore 9 of stopper 8, and then the stopper 8 through the cylindrical body 2, in turn causing fluid contained in the cylindrical body 2 to be ejected through the bore 7.

By adjusting the stroke of the solenoid shaft the amount of drug administered may be adjusted. In one embodiment of the invention the electronic power device may be linked to an electronic scale. The electronic power device, or an interface between the electronic scale and the electronic power device, may be programmed to deliver a quantity of liquid proportional to the weight of the person on the scales, which is achieved by controlling the stroke length of the solenoid.

Such a system reduces the problem associated with over or under dosing and allows less well qualified people to administer the liquid.

The arm 33 sets the distance between the end of the syringe element and the skin into which fluid is to be introduced. An adjustment means may be provided to vary this distance. Such a feature may be useful where different drugs need to reach different depths of the skin for example.

When using the device 20, to administer another dose of drug, the operator simply indexes * *.

the carousel around to the next unused syringe element and breaks off the portion 5, then * S S...

*:::* administers the drug.

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The invention also extends to a method of administering a drug comprising the steps of placing a syringe element containing fluid into a delivery device, positioning the outlet of the syringe element a suitable distance from the surface of the skin and forcing fluid out of the syringe element towards the skin.

The syringe element and delivery device of the invention provide a needle free injection system which is a technical improvement over currently available devices. The provision of a syringe element which is sealed, yet only requires the end to be broken off facilitates easy use and also shows any tampering. The large ratio of bore length to diameter ensures a particular type of fluid flow, which is advantageous when introducing licjuid into the skin. Further, the delivery device provides for easy administration of drugs. * S. * S S * S. S... * . *..S * *5 * e * * *5 * S..

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Claims

Claims 1. A syringe element for a needle-free injection apparatus, the syringe element comprising a cylindrical body having a first end and a second end and providing a bore of a first diameter and a stub providing a bore of a second diameter, wherein the stub extends from the second end and the bore through the stub is in fluid communication with the inside of the cylindrical body, and wherein the ratio of the length of said bore to its diameter is at least 140:1.
2. A syringe element for a needle-free injection apparatus, the syringe element comprising a cylindrical body having a first end and a second end and providing a bore of a first diameter and a stub providing a bore of a second diameter, wherein the stub extends from the second end and the bore through the stub is in fluid communication with the inside of the cylindrical body, and wherein the stub includes a sealing element closing off the bore therein, and wherein the sealing element is detachable from the stub and is formed of the same material as the stub.
3. A syringe element according to Claim 2, wherein the stub includes a point of weakness substantially aligned with the interface between the bore and the sealing element.
4. A syringe element according to Claim 3, wherein the syringe element is formed of glass, and wherein the stub is formed of glass tube, and wherein the sealing element is provided by sealing the bore of the glass tube.
5. A syringe element according to Claim 3 or 4, wherein the point of weakness is provided by at least one score mark on the outer surface of the stub.**
6. A syringe element according to any preceding claim, further comprising a self-sealing *::: . two part syringe closure comprising a stopper and a plug, wherein the stopper includes * ** an opening, and the plug includes an element configured to be inserted into the axial * * * * I. opening.S*SS... * S

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7. A syringe element according to Claim 6, wherein the stopper is formed of an elastically deformable material.
8. A syringe element according to Claim 7, wherein the elastically deformable material is a polymer.
9. A syringe element according to Claim 6, wherein the opening comprises a bore, and the element insertable in the bore comprises a shaft.
10. A syringe element according to Claim 6 or 7, wherein the element insertable into the opening is larger than the opening, and wherein insertion of the said element into the opening causes the stopper to deform creating a seal between the stopper and the plug.
11. A drug ad.ministration device adapted to receive a syringe element as claimed in any of Claims I to 10, comprising at least one syringe element holder and an actuator, wherein the actuator is substantially aligned axially with the syringe element holder.
12. A drug administration device according to Claim 11, wherein the actuator comprises a solenoid.
13. A drug administration device according to Claim 11 or 12, further comprising a source of electrical power.
14. A drug administration device according to any of Claims 11 to 13, comprising a plurality of syringe holding elements formed in a carousel, wherein the carousel is rotatable with respect to the solenoid.
15. A method of administering a drug comprising the steps of: i) placing a syringe element containing fluid into a delivery device; * ii) positioning the outlet of the syringe element a suitable distance from the surface oftheskin;and **** in) forcing fluid out of the syringe element towards the sun.*..:
16. A syringe element substantially as shown in, and as described with reference to, Figures *** * I and 2 of the drawings.

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17. A drug administration device substantially as shown in, and as described with reference to, Figures 3 and 4 of the drawings. * ** * * * * *e * * * ** * * * * S.S *5* * **. S... * S S. SS S S S *5