GB2490723A

GB2490723A - A syringe for human factors studies

Info

Publication number: GB2490723A
Application number: GB201107967A
Authority: GB
Inventors: Ian Charles Cleathero; Lyndon Wild; Neil Bentley Cammish
Original assignee: Medical House Ltd
Current assignee: Medical House Ltd
Priority date: 2011-05-13
Filing date: 2011-05-13
Publication date: 2012-11-14
Anticipated expiration: 2031-05-13
Also published as: GB201107967D0; GB2490723B

Abstract

A syringe for use in a human factors study, comprising: a barrel 12 having a closed forward end 12a and an open rear end 12b, a plunger rod 18 disposed in the barrel and axially moveable therein, and a stopper 16 disposed on the plunger rod, the stopper comprising a fluid passageway 14 for establishing fluid communication between the storage chamber and a rearward end of the stopper. In use, forward axial movement of the plunger and the stopper in the barrel causes an increase in pressure of a liquid contained in the storage chamber, and causes the liquid to flow rearwardly through the fluid passageway in the plug, out of the storage chamber. An absorbent material such as cotton wool 26, 26a, 26b may absorb the liquid being expelled rearwardly from the device. The device may be used in an autoinjector. A method of making the device is provided. A standard syringe may be modified by removing the needle from the front, providing a seal in its place, and using the needle to pierce the stopper and provide the fluid channel.

Description

Modified Syringe [0001] The present invention relates to a syringe, and more particularly to a modified syringe suitable for use in a human factors study, a method of using such a syringe, and a method of manufacturing such a syringe.

BACKGROUND

[0002] Generally, before a syringe or an autoinjector device containing a syringe can be sold to or used on the general public, it must first obtain regulatory approval from the appropriate regulation authority. In many cases, regulatory approval can only be obtained once the syringe and/or autoinjector device has undergone extensive testing to ensure that it is safe for use, is effective and meets the needs of the intended user. Such testing often involves a human factors study whereby test subjects are given the relevant syringe or autoinjector device and are asked to use the syringe or autoinjector in accordance with the given instructions and inject a dose of mock-medicament (usually water). Since it would be unsafe for the test subjects to inject themselves with the syringe or autoinjector device, even with water or other placebo, an injection test pad, or the like, that mimics human tissue, is placed against the patient and the injection is delivered into the pad. The results of these human factors studies are used to determine whether the syringe or autoinjector device is safe, adequately designed and that the instructions provided are clear enough for the intended user to understand and follow.

[0003] It is an object of the present invention to provide a syringe for use in a human factors study or similar test, which negates the requirement of an injection test pad, or the like.

BRIEF SUMMARY OF THE DISCLOSURE

[0004] In accordance with the present invention there is provided a syringe for use in a human factors study, comprising: a barrel having a closed forward end and an open rear end; a plunger rod disposed in the barrel and axially moveable therein; and a stopper disposed on the plunger rod for applying pressure to a liquid contained in a storage chamber of the barrel between a forward end of the stopper and the closed forward end of the barrel, the stopper comprising a fluid passageway for establishing fluid communication between the storage chamber and a rearward end of the stopper; wherein, in use, forward axial movement of the plunger and the stopper in the barr& causes an increase in pressure of a liquid contained in the storage chamber, and causes the liquid to pass rearwardly through the fluid passageway, out of the storage chamber.

(0005] Thus, the syringe does not have a forwardly extending needle but can still hold and expel a volume of liquid, albeit rearwardly. The syringe according to the first aspect of the present invention may therefore be used by a test subject in a human factors study, or the like, where the user operates the syringe whilst pressing the forward end of the syringe against their skin, as they would do with a conventional syringe having a forwardly projecting needle. Consequently, there is no need for an injection test pad and the process more accurately reflects the actual injection process, thus providing more useful results in a human factors study. Additionally, given that the syringe according to the first aspect of the present invention can still hold and expel a volume of liquid (via the fluid passageway), the resistance felt by the plunger rod when moving in the syringe barrel will be substantially the same as it would be in a real injection sequence where medicament is expelled through a forwardly projecting needle.

[0006] In a particularly preferable embodiment, the syringe further comprises an absorbent material arranged to absorb liquid passing rearwardly through the fluid passageway, out of the storage chamber.

[0007] In a further or alternative embodiment, the closed forward end of the barrel comprises a sealed forward opening that is preferably sealed with adhesive. Further preferably the adhesive is an acrylic adhesive. In these preferable embodiments, a conventional syringe may be modified to produce a syringe according to the first aspect of the present invention.

[0008] In another further or alternative embodiment, the fluid passageway comprises a needle passing through the stopper. In this embodiment, the liquid will be expelled through a channel (i.e. the needle) that is similar or identical to the channel that it would pass through when being expelled from a conventional syringe (i.e. the conventional front needle). Indeed, it is preferable, if modifying a conventional syringe to form a syringe according to the first aspect of the present invention, to remove the forwardly projecting needle of the conventional syringe and recycle it by using it to form the fluid passageway through the stopper.

[0009] In one preferable embodiment, the absorbent material is disposed around the plunger rod and is preferably affixed to the plunger rod using an adhesive. In particularly preferable embodiments, the adhesive is cyanoacrylate adhesive.

[0010] In an alternative preferable embodiment, the plunger rod is hollow and comprises a bore for receiving liquid from the storage chamber via the fluid passageway. Preferably, the absorbent material, if present, is disposed within the bore of the plunger rod. In a preferable embodiment, the bore is sized to receive a volume of 1 ml. The plunger rod preferably comprises a radially outwardly projecting flange on its outer surface for receiving a load for moving the plunger rod relative to the barrel, wherein the bore of the plunger rod extends both axially forwards and axially rearwards of the flange. In an alternative or further embodiment, the plunger rod preferably further comprises a porous cap at a rear end that is pervious to air but is configured to substantially prevent liquid from exiting the bore through the rear end.

[0011] Regardless of where the absorbent material is disposed, a preferable absorbent material is cotton wooL In any embodiment where absorbent material is employed, the absorbent material can absorb the expelled liquid thereby preventing the user from coming into contact with the expelled liquid.

[0012] In accordance with a second aspect of the present invention, there is provided an autoinjector device including a syringe according to the first aspect of the present invention.

[0013] In accordance with a third aspect of the present invention, there is provided a method of manufacturing a syringe for use in a human factors study, the method including the steps of: (a) providing a barrel having a closed forward end and an open rear end; (b) providing a stopper and creating a fluid passageway therethrough establishing fluid communication between a forward end of the stopper and a rear end of the stopper; (c) introducing liquid into the barrel through the open rear end; and (d) disposing the stopper on the end of a plunger rod and disposing the stopper in the barrel through the open rear end to define a storage chamber between the forward end of the stopper and the closed forward end of the barrel, wherein the stopper is axially moveable in the barrel.

[0014] Preferably, the method further includes the step of adding an absorbent material to the syringe rearward of the stopper, to absorb liquid passing through the fluid passageway, out of the storage chamber. Further preferably, the step of adding an absorbent material comprises affixing the absorbent material to the plunger rod using an adhesive. Alternatively, the plunger rod is preferably hollow and comprises a bore, and the step of adding absorbent material comprises disposing the absorbent material within the bore of the plunger rod.

[0015] In a further or alternative preferable embodiment, step (a) includes providing a barrel with a forward opening and an open rear end, and sealing the forward opening.

Further preferably, the barrel with the forward opening and the open rear end comprises a barrel having a first needle in fluid communication with the forward opening, and the method further comprises the step of removing the first needle.

[0016] In any method according to the third aspect of the present invention, creating a fluid passageway through the stopper preferably comprises piercing a second needle through the stopper to establish fluid communication between the forward end of the stopper and the rear end of the stopper. Further preferably, a first forwardly projecting needle of the barrel is removed from the barrel prior to piercing the second needle through the stopper, and wherein the first needle and the second needle are the same needle.

After removing the needle from the barrel and prior to piercing the needle through the stopper, the method preferably includes the step of removing any remaining adhesive from the needle.

[0017] In accordance with a fourth aspect of the present invention, there is provided a method of using a syringe, comprising the steps of: (a) providing a syringe according to the first aspect of the present invention; (b) introducing a liquid into the storage chamber; and (c) moving the plunger axially forwards in the barrel to expel the liquid out from the storage chamber through the fluid passageway.

[0018] Prior to step (c), the method preferably includes the step of installing the syringe in an autoinjector device, wherein the method further includes the step of actuating the autoinjector device to cause the plunger to move axially forwards in the barrel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a standard syringe according to the prior art; Figure 2 shows a plunger rod and stopper modified to incorporate a needle that passes through the stopper in accordance with an embodiment of the present invention; Figure 3 shows a syringe barrel with a sealed forward end in accordance with an embodiment of the present invention; Figure 4 shows a stopper and a plunger rod with a portion removed in accordance with an embodiment of the present invention; Figure 5 shows a side view of a syringe according to an embodiment of the present invention; Figure 6A is a perspective view of a plunger rod according to an alternative embodiment of the present invention; and Figure 6B is a cross-sectional view of the plunger rod of Figure 6A.

DETAILED DESCRIPTION

[0020] Figure 1 shows a cross-sectional view of a standard pre-filled syringe 10 according to the prior art. The syringe 10 has a barrel 12 having a forwardly projecting needle 14 at a forward end in fluid communication with a forward opening 12a of the barrel 12. The barrel 12 has an open rear end 12b through which a plunger rod 18 passes to be partially disposed within the barrel 12. At a forward end of the plunger rod 18 is a stopper 16. The plunger rod 18 and stopper 16 are axially movable within the barrel 12. The barrel 12 can contain a volume of liquid, such as medicament, in a so-called storage chamber 20 defined by the stopper 16 and the forward end of the barrel 12.

[0021] A syringe according to the present invention may be manufactured using the components of a conventional pre-filled (or indeed empty) syringe, such as the syringe 10 of Figure 1, however the skilled reader will appreciate that the present invention is not necessarily limited to a syringe manufactured in accordance with this method.

Alternatively, the syringe according to the present invention may be made entirely or partly from components that have not previously been assembled in any way. The foregoing description describes the manufacture of a syringe according to the present invention through modification of the syringe 10 of Figure 1.

[0022] Figure 2 shows the plunger rod 18 and stopper 16 with the needle 14 passing axially through the stopper 16 such that a fluid passageway is established between a front end of the stopper 16 and a rear end of the stopper 16. The needle 14 has thus been removed from the front end of the barrel 12 and pierced through the stopper 16. It may be preferable and/or necessary to remove any adhesive remaining on the needle 14 that previously secured the needle 14 to the forward end of the barrel 12.

[0023] In the preferable embodiment shown in Figure 2, the needle 14 is secured to the plunger rod 18 using an adhesive 22, however alternative embodiments may not include any adhesive 22 between the needle 14 and plunger rod 18. Depending on the dimensions of the plunger rod 18, the plunger rod may need to be modified to allow a channel for the needle 14 to pass through. For example, unmodified, the plunger rod of Figure 4 has a forward flange 18a that would block a needle 14 passing through the stopper 16. Therefore, as shown in Figure 4, the flange 18a of the plunger rod 18 has been machined to leave a cut-out portion 18b that permits a needle 14 to pass through the stopper 16 and reside against the plunger rod 18, where it may be secured with adhesive 22 as shown in Figure 2. In order to machine the plunger rod 18, the plunger rod 18 and stopper 16 will need to be removed from the syringe barrel 12 and the stopper 16 may need to further be removed from the plunger rod 18. After machining of the plunger rod 18, if necessary, the stopper 16 may be affixed to the plunger rod 18 (by screwing, for example) once more before the needle 14 is pushed through the stopper 16 to establish the fluid passageway.

[0024] The forward opening 12a of the barrel 12 is sealed using an adhesive 24 such as an acrylic adhesive (e.g. MA31O) to seal the forward end of the barrel 12, as shown in Figure 3. If any liquid (such as medicament) is present in the syringe barrel, this should be emptied before sealing the forward opening 12a. Once the adhesive 24 is cured, a new liquid may be introduced into the barrel 12. For the purpose of human factors studies, 0.55 ml of water may be a suitable volume. Of course, the actual volume of liquid introduced may vary and will depend on individual requirements.

10025] With the new liquid present in the barrel, the plunger rod 18 and stopper 16 (with needle 14 inserted therethrough) is fitted back into the barrel 12 and moved to the desired axial position therein. The stopper 16 and the forward end of the barrel 12 once again define the storage chamber 20 in which the newly introduced volume of liquid resides.

[0026] An absorbent material, such as cotton wool, for example, may then be arranged rearward of the needle 14 to absorb liquid exiting the storage chamber 20 through the needle 14. in the embodiment shown in Figure 5, the absorbent material 26 is arranged in a first part 26a around a forward portion of the plunger rod 18 and a second part 26b around a rear portion of the plunger rod 18. The absorbent material 26 may be affixed to the plunger rod 18 using a suitable adhesive (not shown), such as cyanoacrylate.

[0027] When complete and assembled, the modifications described above form a modified syringe 10', which is shown in Figure 5. The modified syringe 10' may be operated manually or as part of an autoinjector device (not shown). In either embodiment, the modified syringe 10' is operated by moving the plunger rod 18 axially forwards in the barrel 12. This increases the pressure of the Uquid contained in the storage chamber 20 which in turn causes the liquid to be expelled rearwardly through the needle 14, and be absorbed by the absorbent material 26. Thus, no liquid is expelled through the forward end of the modified syringe 10', as occurs in a convention syringe, such as the syringe 10 shown in Figure 1.

[0028] However, since there is liquid present, and the liquid passes through a channel of the needle 14, just as it would do through the front needle of a conventional syringe, the resistive forces exerted on the plunger rod 18 during expulsion are substantially the same in the modified syringe 101 as they would be in a conventional syringe. The modified syringe 10' therefore allows a close representation of a delivery of medicament to be experienced by the user without the user having to inject themselves or an injection test pad, or the like. The same benefits are realised when the modified syringe 10' is incorporated into an autoinjector device. In this case the autoinjector device is placed against an injection site and actuated, causing a driving means of the autoinjector device to move the plunger rod 18 and stopper 16 axially forwardly in the barrel 12 and cause the liquid to be expelled from the storage chamber, as described above.

[0029] Whilst the above description predominantly relates to the modification of a pre-assembled conventional syringe to form the syringe according to the present invention, the syringe according to the present invention may alternatively be manufactured entirely or partially from components that have not previously been part of an assembly. For example, the syringe barrel may be manufactured with a closed forward end and no forwardly projecting needle such that it is not necessary to remove the needle and seal the forward end. Additionally, the plunger rod may be manufactured such that no extra machining is required to allow a fluid passageway to be established through the stopper.

Indeed, the fluid passageway is not limited to one defined by a needle and may comprise any suitable passageway that permits the rearward passage of liquid out from the storage compartment. The adhesives referred to throughout the description may comprise any suitable adhesive and are not necessarily limited to the examples given. Similarly, the absorbent material may comprise any suitable absorbent material and is not necessarily limited to cotton wool.

[0030] A plunger rod 118 for use in a syringe according to an alternative embodiment of the present invention is shown in Figures 6A and 6B. The plunger rod 118 has a forward end 11 Ba having a screw thread 119 for receiving a screwable stopper (not shown) thereon, and a rear end 118b. The plunger rod 118 is hollow, having a bore 280 running therethrough from the forward end 11 8a to the rear end 11 8b. The bore 280 comprises a forward channel 280a extending axiafly through the screw thread 1195 and a rear chamber 280b which extends rearwardly from the forward channel I 80a to the rear end 11 8b of the plunger rod 118 thereby providing an open rear end. The plunger rod 118 further comprises a radially projecting flange 11 8c which is configured for receiving a load to move the plunger rod 118 in the barr& of a syringe.

[0031] When assembled, the plunger rod 118 has a stopper (not shown) screwed on to the screw thread 1195 and is disposed in the barrel of a syringe (not shown). In other preferable embodiments, the stopper may be affixed to the plunger rod 118 by suitable alternative means.

[0032] An alternative embodiment of a syringe according to the present invention may be manufactured by creating a fluid passageway through the stopper of the plunger road 118 such that a forward end of the stopper (and hence a storage chamber of the syringe axially forwards of the stopper) is in fluid communication with a rearward end of the stopper, and hence also in fluid communication with the forward channel 1 BOa and rear chamber 280b of the plunger rod 118. In a preferable embodiment, the fluid passageway is created through the stopper by piercing the stopper with a needle such that it passes through the stopper and forward channel 280a. In a further preferable embodiment, the needle is left in place to provide a fluid passageway through the stopper from the storage chamber to the rear chamber 280b. If the syringe of the present invention is to be made from the components of a standard syringe, albeit with the plunger rod 118 of Figures 6A and 6B, it may be preferable to remove the forwardly-projecting needle of the standard syringe and pierce the stopper of the plunger rod 118 to form the fluid passageway into the rear chamber 280b via the forward channel 280a. ln any embodiment, the barrel of the syringe has a closed forward end (either formed with a closed forward end or later sealed) for use in a human factors study.

[0033] In use, the syringe would preferably be part of an autoinjector device and would be actuated in the same manner that a conventional syringe would be actuated, i.e. the forward end of the device would be placed against the injection site and the actuation means (such as a button or other trigger) would be actuated to initiate an injection sequence. Upon actuation, the plunger rod 118 is acted upon by a driving means to move the plunger rod 118 axially forwards within the barrel of the syringe and increase the pressure of a liquid contained in the storage chamber. ln a preferable embodiment, the driving means act on the flange 1 18c of the plunger rod 118 in order to move the plunger rod 118 axially forwards. As the pressure of the liquid increases, it begins to flow rearwardly through the fluid passageway through the stopper and into the rear chamber 280b. In a particularly preferable embodiment, the bore 280 of the plunger rod contains an absorbent material, such as cotton wool, for absorbing liquid that has flowed from the storage chamber to the bore 280. In other preferable embodiments, the plunger rod 118 may additionally or alternatively include a rear cap to contain the liquid within the bore 280.

However, such a cap would need to be porous to air or be otherwise capable of venting air from the bore 280 as the liquid is introduced through the fluid passageway. One example of a particularly suitable cap would be a filter tip that is capable of absorbing liquid such that liquid is substantially prevented from exiting the bore 280 via the rear end 11 8b of the plunger rod 118, but allows air from the bore 280 to pass therethrough.

[0034] The plunger rod shown in Figures 6A and SB comprises an extended portion 11 8d extending rearwardly from the flange 11 Bc. In alternative embodiments, the plunger rod 118 may not comprise the extended portion 118d and instead terminate at a rear end 11 8b that is coincident with the flange 11 8c. The extended portion 11 8d provides additional volume in the bore 280 to accommodate one or both of more absorbent material and a greater volume of liquid. In a particularly preferable conflguration, the plunger rod 118 is sized so as to be capable of receiving I ml of liquid within the bore 280. ln alternative embodiments (e.g. where the extended portion 1 18d is not present or is smaller than shown in Figures 6A and SB), the plunger rod 118 may be configured to receive smaller volumes of liquid, such as 0.5 ml, within the bore 280.

(0035] Throughout the description and claims of this specification, the words tcomprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0036] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments.

The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0037] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS1. A syringe for use in a human factors study, comprising: a barrel having a closed forward end and an open rear end; a plunger rod disposed in the barrel and axially moveable therein; and a stopper disposed on the plunger rod for applying pressure to a liquid contained in a storage chamber of the barrel between a forward end of the stopper and the closed forward end of the barrel, the stopper comprising a fluid passageway for establishing fluid communication between the storage chamber and a rearward end of the stopper; wherein, in use, forward axial movement of the plunger and the stopper in the barrel causes an increase in pressure of a liquid contained in the storage chamber, and causes the liquid to pass rearwardly through the fluid passageway, out of the storage chamber.
2. A syringe according to claim 1, further comprising an absorbent material arranged to absorb liquid passing rearwardly through the fluid passageway, out of the storage chamber.
3. A syringe according to any preceding claim, wherein the closed forward end of the barrel comprises a sealed forward opening.
4. A syringe according to claim 7, wherein the sealed forward opening comprises a forward opening sealed with adhesive.
5. A syringe according to claim 8, wherein the adhesive is an acrylic adhesive.
6. A syringe according to any preceding claim, wherein the fluid passageway comprises a needle passing through the stopper.
7. A syringe according to any preceding claim, wherein the absorbent material is disposed around the plunger rod.
8. A syringe according to claim 7, wherein the absorbent material is affixed to the plunger rod using an adhesive.
9. A syringe according to claim 8, wherein the adhesive is cyanoacrylate adhesive.
10. A syringe according to any of claims I to 6, wherein the plunger rod is hollow and comprises a bore for receiving liquid from the storage chamber via the fluid passageway.
11. A syringe according to claim 10 when dependent on claim 2, where the absorbent material is disposed within the bore of the plunger rod.
12. A syringe according to claim 10 or 11, wherein the bore is sized to receive a volume of I ml.
13. A syringe according to any of claims 10 to 12, wherein the plunger rod comprises a radially outwardly projecting flange on its outer surface for receiving a load for moving the plunger rod relative to the barrel, wherein the bore of the plunger rod extends both axially forwards and axially rearwards of the flange.
14. A syringe according to any of claims 10 to 13, wherein the plunger rod further comprises a porous cap at a rear end that is pervious to air but is configured to substantially prevent liquid from exiting the bore through the rear end.
15. A syringe according to claim 2, or any of claims 3 to 14 when dependent on claim 2, wherein the absorbent material is cotton wool.
I 6. An autoinjector device including a syringe according to any preceding claim.
17. A method of manufacturing a syringe for use in a human factors study, the method including the steps of: (a) providing a barrel having a closed forward end and an open rear end; (b) providing a stopper and creating a fluid passageway therethrough establishing fluid communication between a forward end of the stopper and a rear end of the stopper; (c) introducing liquid into the barrel through the open rear end; and (d) disposing the stopper on the end of a plunger rod and disposing the stopper in the barrel through the open rear end to define a storage chamber between the forward end of the stopper and the closed forward end of the barrel, wherein the stopper is axially moveable in the barrel.
18. A method according to claim 17, further including the step of adding an absorbent material to the syringe rearward of the stopper, to absorb liquid passing through the fluid passageway, out of the storage chamber.
19. A method according to claim 17, wherein the step of adding an absorbent material comprises affixing the absorbent material to the plunger rod using an adhesive.
20. A method according to claim 17, wherein the plunger rod is hollow and comprises a bore, and wherein the step of adding absorbent material comprises disposing the absorbent material within the bore of the plunger rod.
21. A method according to any of claims 17 to 20, wherein step (a) includes providing a barrel with a forward opening and an open rear end, and sealing the forward opening.
22. A method according to claim 21, wherein the barrel with the forward opening and the open rear end comprises a barrel having a first needle in fluid communication with the forward opening, and the method further comprises the step of removing the first needle.
23. A method according to any of claims 17 to 22, wherein creating a fluid passageway through the stopper comprises piercing a second needle through the stopper to establish fluid communication between the forward end of the stopper and the rear end of the stopper.
24. A method according to claim 23, wherein a first forwardly projecting needle of the barrel is removed from the barrel prior to piercing the second needle through the stopper, and wherein the first needle and the second needle are the same needle.
25. A method according to claim 24, wherein after removing the needle from the barrel and prior to piercing the needle through the stopper, the method includes the step of removing any remaining adhesive from the needle.
26. A method of using a syringe, comprising the steps of: (a) providing a syringe according to any of claims Ito 15; (b) introducing a liquid into the storage chamber; and (c) moving the plunger axially forwards in the barrel to expel the liquid out from the storage chamber through the fluid passageway.
27. A method according to claim 26, wherein prior to step (c), the method includes the step of installing the syringe in an autoinjector device, and wherein the method further includes the step of actuating the autoinjector device to cause the plunger to move axially forwards in the barrel.
28. A syringe for use in a human factors study substantially as hereinbefore described with reference to the accompanying drawings.
29. A method of manufacturing a syringe for use in a human factors study substantially as hereinbefore described with reference to the accompanying drawings.
30. A method of using a syringe substantially as hereinbefore descrthed with reference to the accompanying drawings!