Technical Field

The present invention relates to a syringe comprising a syringe plunger for preventing re-usage of the syringe as well as a more efficient utilization of the injectable drug which can be manufactured at a cost similar to a conventional syringe.

Background

Misusage of syringes is a common issue, of the 16 billions injections administered each year over 2 million patients and users are infected with severe blood transmittable deceases, such as HIV, Hepatitis B and C. In order to prevent the emergence of decease and infection due to misusage of syringes some syringes are equipped with arrangements for preventing re-usage. This may be especially important with regards to prevent re-usage by addicts. In some instances the prevention is achieved via an arrangement, wherein the needle is retracted into the syringe barrel after one usage whereby additional injections with the syringe are made impossible. In some instances the prevention is achieved by arrangements which destroy the syringe needle after one usage. There are also instances where the prevention is achieved via introduced weaknesses in the syringe plunger which may cause the plunger to deform or brake and thereby preventing re-usage. In further instances re-usage may be prevented by a piece of metal molded into the plunger.

One advantage with such arrangements is that the risk for injuries and decease due to contact with the syringe needle in for example the disposal process is more or less eliminated. However, the arrangements enabling the retracting or destruction of the needles are often complex and more costly to produce. Since the cost for syringes often is a driving factor for the re-usage of conventional syringes, there is a need for more cost-efficient solutions for providing the prevention of re-usage. Another issue with current arrangements for preventing re-usage of syringes is that the volume of the drug in the syringe is not utilized properly. The arrangements are usually disposed inside the cylinder barrel of the syringe, are space-consuming and further limits the volume of the contained drug which is possible to inject through the needle.

Typically, said arrangements prevents injection of the drug disposed in the volume adjacent to the syringe head due to the plunger not reaching all the way distally to the syringe needle and/or the drug getting stuck between the front wall of the cylinder barrel wall disposed adjacent to the syringe head and the syringe head. With the considerable volumes which drugs and syringes are produced such waste represents a significant cost.

Hence, there is a need to provide a syringe which addresses the disadvantages and shortcomings of the prior art in general and to provide a non-reusable syringe which can be manufactured as well as used in a cost-efficient manner.

Summary of the Invention

Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solves at least the above mentioned problems by providing syringe; the syringe comprising a barrel with a lumen, the barrel being adapted to contain the drug; the barrel having a distal end wall portion and a tubular wall extending proximally from the distal end wall portion, whereby the barrel extends along an axis; the distal end wall portion having an opening extending into a syringe head adapted to receive a syringe needle, said syringe head having a lumen smaller in transversal cross-section than the barrel lumen. As is conventional, the syringe head may be a luer, such as a luer grip or a luer slip.

Advantageously, the syringe further comprises a plunger shaft extending along said axis. To enable injection of the contained drug in the barrel said plunger shaft may be displaceable within said barrel. A plunger may be attached to a distal end of said plunger shaft, the plunger being adapted to be in fluid-tight engagement with the tubular wall of the barrel.

Additionally, the plunger has a protrusion adapted to fit in fluid-tight engagement in the lumen of the syringe head.

Preferably, the syringe head comprises at least one axial passage in fluid communication with the barrel, said axial passage being located laterally of the protrusion when the protrusion is positioned in the lumen of the syringe head.

The at least one axial passage allows for a more efficient usage of the drug in the syringe, hence less drug is wasted leading to a more cost-efficient syringe.

The protrusion may further be in a resilient material and be adapted to be retained inside the lumen of the syringe head upon insertion.

An advantage with such a syringe is that re-usage is made impossible due to the plunger being retained inside the syringe head. Thus, a syringe which allows for safer usage of the syringe since re-usage is prevented.

The plunger may comprise a first and second plunger member, the first plunger member being releasably attached to the second plunger member via a locking arrangement. Preferably, the second plunger member may be a top plunger member whereby the first plunger member may be a bottom plunger member.

According to said example the second plunger member comprises the protrusion adapted to fit in fluid-tight engagement in the lumen of the syringe head. The locking arrangement may further be adapted to release the first plunger member from the second plunger member when the plunger shaft is pulled in a direction away from the distal end wall portion after retaining of the protrusion of the second plunger member inside the lumen of the syringe head.

Due to the aforementioned locking arrangement the plunger shaft is separated from the plunger when re-usage is attempted, further ensuring that no re-usage is possible.

The locking arrangement may comprise a locking element, which may be provided by the plunger shaft extending along the axis into the locking element in a resilient material. Preferably, the locking element may be in a resilient material. Said locking arrangement comprises said locking element adapted to be fitted into a locking portion of the second plunger member adapted to receive the locking element, the locking element having a first portion and second portion, the second portion being wider in a direction substantially perpendicular to the axis than said first portion;

whereby the locking portion comprises a narrower wall section adapted to retain the locking element in the locking portion..

The plunger may further be adapted to be prevented from being pulled in a direction away from the distal end wall portion by the negative pressure induced in a volume distal to the plunger by the insertion of the protrusion into the lumen of the syringe head. Thus, no additional retaining features are required, whereby a more cost- efficient manufacturing is possible, while a robust and reliable non-reusability function still can be provided.

The protrusion may also comprise a plurality of projections being adapted to deform so as to increase the friction and prevent the plunger from being pulled in a direction away from the distal end wall portion upon retaining of the protrusion inside the syringe head. Thus, a more robust retaining of the plunger and consequently a more efficient non-reusability function can be achieved.

Further, the wall of the syringe head may comprise grooves adapted to receive the plurality of projections of the protrusion, whereby the non-reusability is further ensured.

Further advantages will be apparent from the detailed description as well as the appended dependent claims.

Brief Description of Drawings

These and other aspects, features and advantages of which the invention is capable, will be apparent and elucidated from the following description of embodiments of the present invention, reference being made to the accompanying drawings, in which

Fig. 1 is a longitudinal section view of the syringe according to one example; Fig. 2 is a side view of the syringe components;

Fig. 3 shows a plunger member of the syringe from a plurality of views; Fig. 4 is a cross-section view of a syringe head of the syringe according to one example;

Fig. 5 is an exterior view of the syringe according to one example;

Fig. 6 is a longitudinal section view of the syringe according to one example; Fig. 7 is a cross-section view of a syringe head of the syringe according to one example;

Fig. 8 is an exterior view of the syringe according to one example.

Detailed Description

Referring to Fig. 1 and 2 a syringe 10 according to an embodiment is shown.

The syringe 10 comprises a barrel 11 with a lumen, preferably of a cylindrical shape, which is adapted to contain a drug in liquid form to be injected into a patient. The barrel 11 has a distal end wall portion 13 and a tubular wall 12 extending proximally from the distal end wall portion 13.

As seen in Fig. 1 the syringe 10 extends along an axis 100 which defines the direction in which the barrel 11 extends, e.g. the barrel 11 extends along the axis 100.

The syringe 10 has a syringe head 40 e.g. a syringe hub for receiving a syringe needle intended for injecting the drug in a patient. The syringe head may be a luer, such as an exterior luer, for example a luer slip or a luer lock. The syringe head 40 further has a lumen which preferably is smaller in transversal cross-section than the barrel lumen.

In Fig. 5 a more detailed view of the syringe head 40 is shown. As seen in Fig.

1 and 5, fluid communication to the syringe needle is enabled by the distal end wall portion 13 having an opening 14 extending into the syringe head 40 i.e. the lumen of the syringe head 40.

Injection of the drug is achieved by moving of a plunger attached to a plunger shaft. Referring again to Fig. 1 a plunger shaft 96 and a plunger 30 for the syringe 10 is disclosed. The plunger shaft 96 extends along the axis 100 and extends into a thumb rest 94. Said plunger shaft 96 being displaceable along the axis 100 within the barrel 11. The plunger 30 is attached to a distal end of the plunger shaft 96 and is adapted to be in fluid-tight engagement with the tubular wall 12 of the barrel 11. Thereby, the drug contained inside the barrel can be injected through the lumen of the syringe head 40 and through the syringe needle.

With reference to Fig. 1 and 5, the syringe head 40 has a lumen smaller in transversal cross-section than the barrel 11, the barrel 11 being in fluid communication with the aforementioned opening extending into the syringe head lumen extending through the entirety of the syringe head 40. The syringe head 40 further comprises at least one axial passage 42 in fluid communication with the barrel 11, the axial passage 42 being located laterally of the protrusion 33 when the protrusion 33 is positioned in the lumen of the syringe head 40. Preferably, axial passage 42 is forming a recess in a wall of the syringe head 41.

Thereby a syringe which enables usage of close to the entire volume of the drug contained in the barrel is provided.

As is disclosed in Fig. 1 to 8 the plunger 30 may have a protrusion 33 which may according to one example constitute of a tapered end 33, adapted to fit in fluid- tight engagement in the lumen of the syringe head 40, the protrusion 33 being in a resilient material such as for example rubber. To provide the prevention of re-usage the protrusion 33 is adapted to be retained inside the lumen of syringe head 40 upon insertion in said syringe head 40. Preferably, the protrusion 33 is wider in a direction perpendicular to the axis 100, i.e. in transversal cross-section, than the syringe head lumen 45, the protrusion 33 as well as the syringe head lumen 45 and the syringe head 40 may be cylindrical or conical, whereby the protrusion 33 may have a diameter larger than the syringe head lumen 45. Thereby, the resilient material of the protrusion 33 can expand which increases the friction between the syringe head wall 41 and the protrusion 33, preventing the user to move the plunger 30. The retaining of the protrusion 33 is shown in for example Fig. 1 wherein the insertion of the protrusion 33 is shown in several states.

The syringe head 40, as presented in Fig 4-5 and 7-8, comprises at least one axial passage 42, but preferably a plurality of axial passage 42 in fluid communication with the cylinder barrel 11. The axial passages 42 are each adapted to allow fluid communication between the barrel 11 and the axial passage 45. Preferably, the one or more axial passages 42 are forming recesses in the wall 41 of the syringe head 40. Thereby, the drug is allowed to enter the syringe head 40 even after the protrusion 33 has entered the lumen of the syringe head 40. Hence, a syringe which prevents re-usage as well as increases the utilization of the contained drug is achieved.

As is evident from Fig. 5 and 8 the at least one axial passage 42

advantageously extends from the distal end wall portion 13 parallel to the axis 100 to a location situated at a distance from a distal end 44 of the syringe head 40. This is particularly advantageous with regards to manufacturing costs since the thickness of the material at the distal end 44 of the syringe head 40 can be held constant which enables a less complex sealing arrangement in the molding tool and less wear of said molding tool. In the case of the recess extending all the way to the distal end, the metal tool required for molding said recesses will abut to the metal tool for molding the syringe body. Due to no castings being present between the tools which consequently will be in metal-to-metal contact with each other severe wear of the tools may occur. The increased wear consequently leads to less exact tolerances which may require the tools to be replaced.

Referring to Fig. 3 the protrusion 33 has a distal protrusion end 34, whereby the distal protrusion end 34 may be narrower in a direction substantially perpendicular to the axis 100 than said protrusion 33 so as to enable fluid communication between the at least one axial passage 42 and the distal end 44 of the syringe head 40 upon insertion of the protrusion 33 inside the lumen of the syringe head 40. Thereby a fluid path from the opening 14 extending through the at least one axial passage 42 to the distal end 44 is established. The drug can thereby pass the entire protrusion 33 and reach the distal end 44 of the syringe head 40 even when the protrusion 31 is fully inserted inside lumen of the syringe head 40 due to the resulting axially extending gap between the wall of the syringe head 41 and the protrusion 33 towards the distal end of the at least one axial passage 42. Consequently, the usage of the drug contained inside the barrel is further increased resulting in a syringe with a more cost-efficient usage.

With reference to Fig. 1, 5, 6 and 8 the retaining of the protrusion 33 of the plunger in the syringe head 40 can be achieved with a number of means. Referencing Fig. 1 the retaining may simply be achieved by the protrusion 33 comprising a material with properties which makes it impossible for a user to pull the plunger shaft 96 in a direction away from the distal end wall portion 13 after insertion, preferably after complete insertion, of the protrusion 33 inside the lumen of the syringe head 40. Thus, the protrusion 33 may comprise a resilient material with a friction coefficient chosen so as to enable retaining of the plunger 33 inside the lumen of the syringe head 40 upon insertion.

With such material the protrusion 33 may be retained in the lumen of the syringe head 40 without requiring any structural retaining features. Instead, only the friction between the syringe head 40 and the protrusion end 33 in conjunction with the capillary force induced by the relatively small volume remaining drug in the syringe head and the negative pressure generated when the protrusion 33 is retained in the lumen of the syringe head 40 is enough for preventing the plunger shaft 96 to be pulled in a direction away from the distal end wall portion 13. Said negative pressure occurs due to the pressure difference between the volumes in the barrel 11 distal and proximal to the plunger 30 when the protrusion 33 has been inserted into the lumen of the syringe head 40, which effectively creates a low pressure zone distal to the plunger 30. Attempts to pull the plunger 30 in a direction away, i.e. proximally from the syringe head 40 is thus made impossible due to the suction effect holding the protrusion 33 inside the lumen of the syringe head 40.

Accordingly, the plunger 30 may be adapted to be prevented from being pulled in a direction away from the distal end wall portion 13 by the negative pressure induced in a volume distal to the plunger 30 by the insertion of the protrusion 33 into the lumen of the syringe head 40. Said volume distal to the plunger may hence be a volume between the plunger 30 and the distal end wall portion 13 and/or the lumen of the syringe head 40.

Since the capillary force and friction force increases with the contact surface, the material can be chosen so as to have a friction coefficient which allows for insertion of the entire tapered end 33 inside the syringe head 40.

With the aforementioned retaining arrangement no structural additional features are required which allows for a less costly manufacturing process. Notably, the arrangement simply utilizes the pressure phenomena occurring inside the syringe to achieve the non-reusability function. This does not require any costly extra components or more advanced manufacturing methods, instead a syringe with a robust and reliable non-reusability function can be achieved without high manufacturing costs.

Advantageously, the difference in E-modulus between the material of the syringe head 40 and the protrusion 33 should be as large as possible. Preferably, the syringe head 40 is in a material with a higher E-modulus than the tapered end 33. Thus, the syringe head 40 may be in polypropylene (PP) and the protrusion 33 in an elastomeric material.

Advantageously, the syringe head, e.g. the interior of the syringe head, as well as the protrusion may be polished to further maximize the suction effect and the generated negative pressure. This is achieved by the finer surfaces allowing for a more fluid-tight engagement between the syringe head wall and the protrusion 33 which increases the difference in pressure between the volume proximate and distal of the plunger 30. Also, the syringe head and the protrusion may be treated with silicone.

As depicted in Fig. 6 the retaining may be retained by means to increase the friction, whereby the protrusion 33 is in a resilient material and comprises a plurality of projections 35, which may extend in a direction perpendicular to the axis 100, e.g. being transversally extending projections.

Accordingly, the protrusion 33 may comprise a plurality of projections 35 being adapted to deform due to insertion of said protrusion 33 in the lumen of the syringe head 40 so as to increase the friction and prevent the plunger 30 from being pulled in a direction away from the distal end wall portion 13 upon retaining of the protrusion 33 inside the syringe head 40. Thereby, a reliable and robust non-reusability function which does not require any complex components or arrangements within the barrel or syringe head can be provided.

Advantageously, said projections may be radial projections extending from a substantially cylindrical protrusion 33. To achieve the retaining function the diameter of the projections 35 may be larger than the diameter of the syringe head lumen 45.

Thereby, the projections 35 of the protrusion 33 are deformed upon insertion in the lumen of the syringe head 40 the friction force retaining the protrusion 33 increases greatly. Hence, the projections are adapted to deform so as to retain the protrusion 33 inside the lumen of syringe head 40 upon insertion in said lumen of the syringe head 40.

Referring to Fig. 8, the retention of the protrusion 33 may be enabled by the wall of the syringe head 41 comprising grooves 43 adapted to receive a plurality of projections 35 of the protrusion 33. Said grooves 43 may be adapted to hold said projections 35 so as to prevent movement of the plunger 30 in a direction away from the distal end wall portion 13, i.e. in a proximal direction of the syringe 10. Thus, a reliable and non-complex non-reusability function can be provided.

Advantageously, the projections 35 or the entire protrusion 33 may be in a rubber material, such as synthetic isoprene rubber whereby the syringe head 40 and/or the grooves 43 may be in a material with a higher E-modulus such as polypropylene (PP). Thereby, the projections 35 may be compressed inside the grooves 43 leading to the retaining effect. Preferably, either the projections 35 or the grooves may be treated with silicone, which decreases the friction upon insertion and makes it easier for the protrusion 33 to be inserted inside the lumen of the syringe head 40, making the syringe more user-friendly.

As presented in Fig. 6 the syringe 10 may further comprise a locking arrangement 50 which is adapted to be released when the plunger shaft 96 is pulled in a direction away from the distal end wall portion 13, i.e. proximally, after retaining of the protrusion 33 of the plunger 30 inside the lumen of the syringe head 40. Accordingly, any attempted re-usage of the syringe will result in the plunger shaft being separated from the plunger whereby further injections are made impossible.

With reference to Fig 5 and 8, a second plunger member 31 comprises a substantially conical section 36 extending into the protrusion 33, in this case a tapered end 33. The substantially conical section 36 is adapted to be in fluid-tight engagement with the tubular wall 12 and the first wall portion 14.

Further referring to Fig. 6 the aforementioned functionality is provided by the plunger 30 comprising a first plunger member 31 and a second plunger member 32, the first plunger member 31 being releasably attached to the second plunger member 32 via the locking arrangement 50. Thus, it may be the second plunger member 32 which comprise the protrusion 33 of the plunger which is adapted to fit in fluid-tight engagement in the lumen of the syringe head 40.

In order to provide the non-reusability, the locking arrangement 50 is adapted to release the first plunger member 31 from the second plunger member 32 when the plunger shaft 96 is pulled in a direction away from the distal end wall portion 13 after retaining of the protrusion 33 of the second plunger member 32 inside the lumen of syringe head 40.

Fig. 6 presents an example of such a locking arrangement in further detail; said locking arrangement 50 may comprise a locking element 51, whereby the plunger shaft 96 extends along the axis into said locking element 51.

The locking element 51 is preferably adapted to be fitted into a locking portion 53 of the second plunger member 32. To retain the locking element 51, , the locking portion further comprising a narrower wall section 54 which is adapted to retain the locking element 51 in the locking portion 53. This is achieved by the locking element 51 comprising a first portion 31 and a second portion 32 which is wider in transversal cross-section, e.g. a direction perpendicular to the axis 100, than the first portion 31 in a direction, thereby the resilient elastic locking element 51 can be elastically deformed so as to enable the insertion of said locking element 51 through the narrower wall section 54. Thus, the locking element 51 can revert back to its original shape inside the locking portion 53, whereby an upper surface of the second portion abuts against a lower surface of the narrower wall section retaining the locking element 51. Hence, the narrower wall section 54 may be a locking shoulder adapted to be in engagement with the locking element 51. The locking element 51 may thus be a locking arm adapted to be fitted into the locking portion 53 and being retained by said locking shoulder.

With the locking arrangement described above any re-usage may be prevented due to the locking element 51 being adapted to be released from the recess 52 when a user attempts to pull the plunger shaft 96 in a direction away from the distal end wall portion 13. Notably, with the aforementioned embodiment of the locking arrangement

50 pushing of the plunger shaft 96 towards the distal end wall portion 13 will not cause any separation of the plunger members since it will simply cause pushing of the locking

51 element against the interior bottom of the recess 52. Fig. 2 and 3 shows the syringe 10 and the plunger arrangement in particular. As depicted, the second plunger member has an upper surface 38 substantially

perpendicular to the axis 100. The second plunger member 31 comprising at least one, preferably a plurality of, protruding element 37 which extends from the upper surface 38. Hence, the upper surface 38 may be adapted to abut against a lower surface 39 of the first plunger member which also extends perpendicularly to the axis 100. Hence, the locking element is further supported during movement of the plunger, whereby a more robust locking arrangement is achieved.

Further, the invention has mainly been described with reference to a few embodiments. However, as is readily understood by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended claims.