Syringe with aspiration-based automatic disabling

Abstract

A syringe is provided that includes a syringe barrel having a barrel proximal end and a barrel distal end and defining a chamber configured to receive a fluid therein. The syringe also includes a plunger axially movable within the chamber of the syringe barrel, the plunger having a plunger proximal end and a plunger distal end. The syringe also includes a stopper secured to the plunger distal end, the stopper being axially movable with the plunger within the chamber, where the stopper has an attachment member configured to be coupled to the plunger distal end and a cup member extending distally from the attachment member, the cup member having a concave shape.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Patent Application No. 17 / 979,430, titled "Syringe with Suction - Based Automatic Disablement", filed on November 2, 2022, the entire disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to syringes, and more particularly, to disposable syringes having features for automatically precluding reuse of the syringe. Background Art

[0004] Syringes are used to administer fluids, such as medications, to patients in a variety of settings. Many syringes are designed as disposable devices and are discarded after use. Reuse of such disposable syringes, which may occur at a high rate in developing countries, can lead to the transmission of various blood - borne diseases and / or pathogens, such as hepatitis and HIV.

[0005] Many disposable syringes have been designed to address the problem of unauthorized reuse by being designed to be inoperable after initial use of the syringe. Some of these disposable syringes may include locking elements or features positioned within the syringe barrel and / or on the plunger of the syringe, where the locking element prevents the plunger from retracting after injecting / administering fluid to the patient. Other disposable syringes may include additional locking elements separate from the syringe barrel and plunger that prevent the plunger from retracting after injecting / administering fluid to the patient. In either design, the locking elements or features generally increase the cost and / or complexity of the syringe manufacturing and assembly process, such as by requiring complex molded parts or additional assembly steps during manufacturing.

[0006] Accordingly, there is a need in the art for a disposable syringe that effectively disables the syringe after initial use to prevent its reuse, but can be manufactured at low cost and with minimal assembly steps. Summary of the Invention

[0007] Provided herein is a syringe that includes a syringe barrel having a barrel proximal end and a barrel distal end and defining a chamber configured to receive a fluid therein. The syringe further includes a plunger axially movable within the chamber of the syringe barrel, the plunger having a plunger proximal end and a plunger distal end. The syringe further includes a stopper fixed to the plunger distal end, the stopper axially movable within the chamber together with the plunger, wherein the stopper has an attachment member configured to couple to the plunger distal end and a cup member extending distally from the attachment member, the cup member having a concave shape.

[0008] In some embodiments, the syringe barrel includes a cylindrical outer wall extending between a proximal end and a distal end of the barrel, an end wall positioned at the distal end of the barrel, and a nozzle extending distally from the end wall, the nozzle defining a lumen through which fluid enters or exits the chamber, wherein an inner surface of the end wall has a generally flat surface.

[0009] In some embodiments, the cup member is made of a flexible material such that the cup member is deflectable between a concave shape and a flat shape.

[0010] In some embodiments, the stopper includes a nose member extending distally beyond the cup member, the nose member being positioned within the perimeter of the cup member.

[0011] In some embodiments, the plunger and the stopper coupled thereto are movable from a retracted position, in which the cup member and the nose member are axially separated from the end wall, to a forward position, in which the cup member contacts the end wall and the nose member extends into the nozzle.

[0012] In some embodiments, with the plunger and the stopper in the forward position, the nose member extends into the nozzle and the cup member deflects from a concave shape to a flat shape, thereby creating a suction between the stopper and the end wall of the syringe barrel.

[0013] In some embodiments, with the plunger and the stopper in the forward position, the stopper is suctioned to the end wall by a suction force greater than the coupling force that couples the stopper to the plunger.

[0014] In some embodiments, the distal end of the plunger includes a flanged extension member, and the attachment member of the stopper includes a receiving portion formed therein, wherein the flanged extension member is coupled to the receiving portion by a press fit connection to secure the stopper to the plunger.

[0015] In some embodiments, with the stopper suctioned to the end wall, when a proximally directed pulling force greater than the coupling force is applied to the plunger, the flanged extension member is pulled out of the receiving portion, thereby separating the stopper from the plunger.

[0016] In some embodiments, with the stopper separated from the plunger, the stopper is captured in the forward position, thereby preventing reuse of the syringe.

[0017] In some embodiments, the inner surface of the end wall includes a surface treatment thereon that increases the suction between the cup member and the end wall.

[0018] In some embodiments, the syringe barrel includes a retaining ring formed on its inner surface, the retaining ring being positioned toward the proximal end of the barrel, and wherein the plunger includes an annular rib formed thereon and positioned toward the proximal end of the plunger, wherein when the plunger and the stopper are in the retracted position, the annular rib is proximal to the retaining ring.

[0019] In some embodiments, to move the plunger and the stopper to the advanced position, the distally-directed force applied to the plunger must be greater than the frictional force between the annular rib and the retaining ring.

[0020] Also provided herein is a method of manufacturing a syringe as described above. The method includes providing a syringe barrel, fixing a stopper to a plunger by coupling an attachment member to the distal end of the plunger, and positioning a portion of the stopper and the plunger within the chamber of the syringe barrel. When positioning the portion of the stopper and the plunger within the chamber, the plunger and the stopper are placed in an initial position in which the cup member is separated from the distal end of the barrel.

[0021] Also provided herein is a syringe that includes a syringe barrel having a proximal end and a distal end of the barrel and defining a chamber configured to receive a fluid therein. The syringe further includes a plunger assembly that is axially movable within the chamber of the syringe barrel between a retracted position and an advanced position, wherein the plunger assembly further includes a plunger having a proximal end and a distal end of the plunger and a stopper fixed to the distal end of the plunger, the stopper being configured to be aspirated to the distal end of the barrel when the plunger assembly moves to the advanced position. The stopper is further configured to separate from the plunger and remain aspirated to the distal end of the barrel when the plunger axially moves back from the advanced position toward the retracted position.

[0022] In some embodiments, the stopper includes an attachment member configured to couple to the distal end of the plunger, a cup member extending distally from the attachment member and having a concave shape, wherein the cup member is deflectable between the concave shape and a flat shape, and a nose member extending distally from the attachment member and extending beyond the cup member, the nose member being positioned within the perimeter of the cup member.

[0023] In some embodiments, the distal end of the plunger includes a flanged extension member, and the attachment member of the stopper includes a receiving portion formed therein, wherein the flanged extension member is coupled to the receiving portion by a press fit connection to fix the stopper to the plunger. In the case where the stopper is aspirated to the distal end of the barrel, when the plunger axially moves back from the advanced position to the retracted position, the flanged extension member is pulled out of the receiving portion.

[0024] In some embodiments, the syringe barrel includes a cylindrical outer wall extending between the proximal end and the distal end of the barrel, an end wall positioned at the distal end of the barrel, and a nozzle extending distally from the end wall, the nozzle defining an inner lumen through which fluid enters or exits the chamber, wherein the inner surface of the end wall has a generally flat surface.

[0025] In some embodiments, when the plunger assembly is in the advanced position, the nose member extends into the nozzle and the cup member contacts the end wall and deflects from the concave shape to the flat shape, thereby aspirating the stopper to the end wall of the syringe barrel.

[0026] In some embodiments, the syringe barrel includes a retaining ring formed on its inner surface, the retaining ring being positioned towards the proximal end of the barrel, and the plunger includes an annular rib formed thereon and positioned towards the proximal end of the plunger, wherein when the plunger and the stopper are in the retracted position, the annular rib is proximal to the retaining ring. To move the plunger and the stopper to the advanced position, the distally directed force applied to the plunger assembly must be greater than the frictional force between the annular rib and the retaining ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view of a syringe according to non-limiting embodiments described herein;

[0028] Figure 2 is Figure 1 an exploded view of the syringe;

[0029] Figure 3 is an Figure 1 side cross-sectional view of the stopper included in the syringe;

[0030] Figure 4 is Figure 1 side cross-sectional view of the syringe, wherein the plunger assembly is in an initial or pre-use position;

[0031] Figure 5 is Figure 1 side cross-sectional view of the syringe, wherein the plunger assembly is in a retracted position before first use;

[0032] Figure 6 is Figure 1 side cross-sectional view of the syringe, wherein the plunger assembly is in an advanced position;

[0033] Figure 7 is Figure 1 side cross-sectional view of the syringe, wherein the stopper is separated from the plunger after first use. DETAILED DESCRIPTION

[0034] The following description is provided to enable a person skilled in the art to make and use the described embodiments contemplated for carrying out the invention. However, various modifications, equivalents, variations, and alternatives will still be apparent to a person skilled in the art. Any and all such modifications, equivalents, variations, and alternatives are intended to fall within the spirit and scope of the invention.

[0035] For the purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and derivatives thereof shall relate to the present invention as shown in the drawings. However, it should be understood that the present invention may take various alternative variations, unless expressly stated to the contrary. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Accordingly, the specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered limiting.

[0036] As used in this specification, the terms "proximal" and "distal" refer respectively to the directions towards and away from the user who places the device in contact with the patient. Thus, for example, the end of the device that first contacts the patient's body will be the distal end, while the opposite end of the device that is manipulated by the user will be the proximal end of the device.

[0037] The terms "first", "second", etc. are not intended to refer to any particular order or time sequence, but rather to different conditions, properties or elements.

[0038] Reference Figures 1 to 7 , there is shown a non-limiting embodiment of a disposable syringe 10. The syringe 10 generally includes a syringe barrel 12 and a plunger assembly 14. The plunger assembly 14 is axially movable within the syringe barrel 12 between a retracted position ( Figure 5 ) and an advanced position ( Figure 6 ) to, for example, facilitate the administration of an injectable fluid (e.g., a drug) to a patient.

[0039] The syringe barrel 12 is formed by a generally cylindrical outer wall 16 and an end wall 18, which together define a chamber 20 for holding fluid. The syringe barrel 12 includes an open proximal end 22 configured to receive the plunger assembly 14 therein and a distal end 24 at which the end wall 18 is located. The proximal end 22 of the syringe barrel 12 may include a flange 26 to facilitate the operation and positioning of the syringe 10 and to maintain the relative position of the syringe barrel 12 with respect to the plunger assembly 14 during drug administration. At the distal end 24, a nozzle 28 extends distally outwardly from the end wall 18 and defines an inner lumen 30 in fluid communication with the chamber 20. In some embodiments, the nozzle 28 may be configured as a Luer connection (male Luer connection), which may be coupled to a corresponding needleless connector (not shown) to which the syringe 10 will be placed in engagement to administer a drug to a patient. It will be understood that other types of attachment means may be provided to secure the distal end 24 of the syringe barrel 12 to discharge the injectable material into the target location.

[0040] The plunger assembly 14 of the syringe 10 is formed by an elongate plunger rod 32 (more generally referred to as "the plunger 32" as used hereinafter) and a plunger head or stopper 34. The plunger 32 may include a body 36 extending between a proximal plunger end 38 and a distal plunger end 40. In some embodiments, the body 36 may include a plurality of elongate vanes or walls 42 extending axially along its length between the proximal plunger end 38 and the distal plunger end 40. A thumb press 44 is located at the proximal plunger end 38 and may be engaged by the user's thumb (or other finger) to apply a distally-directed force to the plunger assembly 14, thereby moving the plunger 32 relative to the syringe barrel 12. In some embodiments, a flanged extension member 46 (e.g., a disk-shaped flange) is located at the distal plunger end 40 and is configured to mate with the stopper 34.

[0041] The stopper 34 of the plunger assembly 14 is located at the distal plunger end 40 so as to be movable together with the plunger 32 within the chamber 20 of the syringe barrel 12. The stopper 34 may be made of a material different from that of the plunger 32, wherein the stopper 34 is formed of a flexible elastomeric material, for example, capable of forming a tight seal with the syringe barrel as the stopper 34 advances through the syringe barrel 12. The stopper 34 may generally be defined as including an attachment member 48, a cup member 50, and a nose member 52. The attachment member 48 is provided at the proximal end 54 of the stopper 34 and is configured to mate with the plunger 32. In some embodiments, the attachment member 48 includes a receiving portion 56 formed therein ( Figure 3 ), the size and configuration of the receiving portion being designed to receive the flanged extension member 46 of the plunger 32, wherein the flanged extension member 46 is coupled to the receiving portion 56, for example, by a press-fit connection to fix the stopper 34 to the plunger 32, but it will be understood that the attachment member 48 and the distal plunger end 40 may be fixed by other techniques known in the art. The attachment member 48 may also include a pair of spaced-apart annular flanges 58 (i.e., O-rings) formed thereon, which form a tight seal with the cylindrical outer wall 16 of the syringe barrel 12.

[0042] The cup member 50 extends distally away from the attachment member 48 so as to face the end wall 18 of the syringe barrel 12. The cup member 50 is configured to have a distally-facing surface 60 with a concave shape. As described above, the stopper 34 - including the cup member 50 - is formed of a flexible material such that the cup member 50 is deformable and can change from having a concave shape to having a generally flat profile or shape when pressure is applied thereto. In some embodiments, the cup member 50 may be formed to have a diameter slightly smaller than the diameter of the attachment member 48 (i.e., the O-ring 58 of the attachment member 48), such that the cup member 50 does not form a tight seal with the cylindrical outer wall 16 of the syringe barrel 12

[0043] The nasal member 52 extends distally away from the attachment member 48 and outwardly beyond the cup member 50 of the plug 34. The nasal member 52 is positioned within the perimeter of the cup member 50 and centered on the plug 34 such that the nasal member 52 is aligned with the nozzle 28 of the syringe barrel 12. The nasal member 52 is sized and configured to cooperate with the nozzle 28 when the plunger assembly 14 is axially moved to the advanced position, wherein when so cooperating, the nasal member 52 forms a seal with the nozzle 28.

[0044] In accordance with aspects of the present disclosure, the syringe 10 is configured to include an automatic disable feature incorporated therein that prevents the syringe 10 from being reused after its initial use - i.e., after a drug has been initially administered from the syringe 10. Specifically, the cup member 50 of the plug 34 is configured to form a suction engagement with the end wall 18 of the syringe barrel 12 when the plunger assembly 14 is actuated to the advanced position. In the case where the cup member 50 is suctioned to the end wall 18 of the syringe barrel 12, a subsequent attempt to actuate the plunger assembly 14 back to the retracted position (i.e., by applying a proximally directed force to the plunger 32) will result in the plug 34 disengaging and separating from the plunger 32. When disengaged from the plunger 32, the plug 34 is captured in the advanced position, thereby limiting the use of the syringe 10 to a single / initial use and precluding the syringe 10 from being used in subsequent injection applications.

[0045] Reference Figures 4 to 7 , the syringe 10 is shown in various stages of its use or actuation to better explain and illustrate the automatic disable feature of the syringe 10. First reference Figure 4 , the syringe 10 is shown in its initial or pre-use position, such as the position that occurs when the syringe 10 is unpacked. In its initial position, the plunger assembly 14 of the syringe 10 is located within the syringe barrel 12 at a position between the previously mentioned fully retracted position and the fully advanced position. In the initial position, the plug 34 is spaced apart from the end wall 18 of the syringe barrel 12 such that the cup member 50 of the plug 34 does not contact the end wall 18 (and cannot be suctioned to the end wall 18). According to some embodiments, a retaining ring 62 and an annular rib 64 are respectively provided on the syringe barrel 12 and the plunger 32, which serve to hold the syringe 10 in its initial position and prevent accidental actuation to the advanced position. The retaining ring 62 is formed on the inner surface 66 of the syringe barrel 12, toward its proximal end 22, and the annular rib 64 is similarly formed on the plunger 32, toward its proximal end 38, wherein when the plunger assembly 14 is in the initial position, the annular rib 64 is located proximal to the retaining ring 62. The retaining ring 62 and the annular rib 64 hold the syringe 10 in its initial position because a distally directed force needs to be applied to the plunger assembly 14 in order to slide the annular rib 64 distally past the retaining ring 62, thereby moving the plunger assembly 14 to the advanced position (i.e., a distally directed force greater than the frictional force between the annular rib 64 and the retaining ring 62 must be applied to the plunger assembly 14).

[0046] As Figure 5 shown, the syringe 10 can be pulled back from its initial position to its retracted position to allow a clinician to draw a drug into the syringe barrel 12. The clinician can apply a proximally-directed force to the plunger assembly 14, such as by gripping the flange 26 of the syringe barrel 12 and / or the thumb press 44 on the plunger 32 and applying pressure thereto, thereby causing the plunger 32 and the stopper 34 to retract to the retracted position.

[0047] Turning to Figure 6 , when it is desired to administer the drug from the syringe 10 to a patient, the syringe 10 is actuated to its advanced position. The clinician can apply a distally-directed force to the plunger assembly 14, such as by gripping the flange 26 of the syringe barrel 12 and the thumb press 44 on the plunger 32 and applying pressure thereto, thereby causing the plunger 32 and the stopper 34 to translate to the advanced position. As described above, in some embodiments, the magnitude of the force required to move the plunger 32 and the stopper 34 to the advanced position may need to be sufficient to overcome the frictional force between the annular rib 64 and the retaining ring 62. In the case where the plunger assembly 14 is actuated to the advanced position, the nose member 52 of the stopper 34 is pushed into and forms a seal with the mouth 28 of the syringe barrel 12. Additionally, actuation of the plunger assembly 14 to the advanced position causes the cup member 50 of the stopper 34 to be placed in strong contact with the end wall 18 of the syringe barrel 12. This strong contact between the cup member 50 and the end wall 18 causes the cup member 50 to deflect from its concave shape to a generally flat shape and creates a suction force between the cup member 50 and the end wall 18. In some embodiments, a surface treatment 68 (e.g., a gloss treatment) can be applied to the end wall 18, which promotes or enhances the formation of a seal between the cup member 50 and the end wall 18, thereby creating a strong suction therebetween.

[0048] Now referring to Figure 7, if an attempt is made to reuse syringe 10—where the user attempts to draw more medication into syringe barrel 12 by pulling plunger assembly 14 back to the retracted position—the syringe 10 is automatically disabled and such use is prevented. That is, as described above, when the plunger assembly 14 is actuated to the advanced position, the cup member 50 of the stopper 34 is drawn to the end wall 18 of the syringe barrel 12. This suction force between the cup member 50 and the end wall 18 is greater than the coupling force between the stopper 34 and the plunger 32 (e.g., between the flanged extension member 46 of the plunger 32 and the receiving portion 56 of the stopper 34). Thus, when a proximally directed pulling force greater than the coupling force is applied to the plunger 32, the stopper 34 disengages from the plunger 32—resulting in the separation of the stopper 34 from the plunger 32. When a proximally directed pulling force is applied thereto, the plunger 32 can thus be pulled back toward the retracted position, but the stopper 34 remains drawn to the end wall 18 of the syringe barrel 12 and stays in the advanced position. Accordingly, the stopper 34 is captured in the advanced position and the syringe 10 becomes disabled and unfit for reuse.

[0049] Advantageously, aspects of the present disclosure described herein provide a disposable syringe that includes an automatic-disable feature incorporated therein. The automatic-disable feature prevents the syringe from being reused after the first administration of medication therefrom. The automatic-disable is included in the syringe at low cost, where no additional assembly steps are required during manufacturing. When the plunger assembly of the syringe is moved to the advanced position to administer medication to a patient, a concave cup member included on the stopper of the syringe forms a suction engagement with the distal end wall of the syringe barrel. Once the cup member forms a suction with the end wall of the syringe barrel, any subsequent retraction of the plunger in the proximal direction will cause the plunger to separate from the stopper, while the stopper remains at the distal end of the syringe barrel. In the case where the stopper is disconnected from the plunger and captured at the distal end of the syringe barrel, the syringe is disabled and any reuse of the syringe in other injection applications is prohibited.

[0050] While the present disclosure has been described in detail for purposes of illustration based on the currently considered most practical and preferred embodiments or aspects, it is to be understood that such detail is for that purpose only and that the present disclosure is not limited to the disclosed embodiments or aspects, but rather, is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment may be combined with one or more features of any other embodiment.

Claims

1. A syringe, the syringe comprising: A syringe barrel having a barrel proximal end and a barrel distal end and defining a chamber configured to receive a fluid therein; A plunger capable of axially moving within the chamber of the syringe barrel, the plunger having a plunger proximal end and a plunger distal end; And A stopper fixed to the plunger distal end, the stopper capable of axially moving within the chamber together with the plunger, wherein the stopper includes: An attachment member configured to be coupled to the plunger distal end, and A cup member extending distally from the attachment member, the cup member having a concave shape.

2. The syringe according to claim 1, wherein the syringe barrel comprises: A cylindrical outer wall extending between the barrel proximal end and the barrel distal end; An end wall positioned at the barrel distal end; And A nozzle extending distally from the end wall, the nozzle defining an inner cavity through which fluid enters or exits the chamber; Wherein the inner surface of the end wall includes a substantially flat surface.

3. The syringe according to claim 2, wherein the cup member is made of a flexible material such that the cup member is capable of deflecting between a concave shape and a flat shape.

4. The syringe according to claim 3, wherein the stopper comprises a nose member extending distally beyond the cup member, the nose member being positioned within the perimeter of the cup member.

5. The syringe according to claim 4, wherein the plunger and the stopper coupled thereto are movable from a retracted position to a forward position, in the retracted position, the cup member and the nose member are axially separated from the end wall, and in the forward position, the cup member contacts the end wall and the nose member extends into the mouthpiece.

6. The syringe according to claim 5, wherein when the plunger and the stopper are in the forward position, the nose member extends into the mouthpiece and the cup member deflects from a concave shape to a flat shape, thereby creating a suction between the stopper and the end wall of the syringe barrel.

7. The syringe according to claim 6, wherein when the plunger and the stopper are in the forward position, the stopper is suctioned to the end wall by a suction force greater than the coupling force that couples the stopper to the plunger.

8. The syringe according to claim 7, wherein the distal end of the plunger comprises a flanged extension member, and the attachment member of the stopper comprises a receiving portion formed therein, wherein the flanged extension member is coupled to the receiving portion by a press fit connection to fix the stopper to the plunger.

9. The syringe according to claim 8, wherein when the stopper is suctioned to the end wall, when a proximally directed pulling force greater than the coupling force is applied to the plunger, the flanged extension member is pulled out of the receiving portion, thereby separating the stopper from the plunger.

10. The syringe according to claim 9, wherein when the stopper is separated from the plunger, the stopper is captured in the forward position, thereby preventing reuse of the syringe.

11. The syringe according to claim 6, wherein the inner surface of the end wall includes a surface treatment thereon that increases the suction between the cup member and the end wall.

12. The syringe according to claim 5, wherein the syringe barrel includes a retaining ring formed on its inner surface, the retaining ring being positioned towards the proximal end of the barrel, and wherein the plunger includes an annular rib formed thereon and positioned towards the proximal end of the plunger, wherein when the plunger and the stopper are in the retracted position, the annular rib is proximal to the retaining ring.

13. The syringe according to claim 12, wherein in order to move the plunger and the stopper to the advanced position, the distally directed force applied to the plunger must be greater than the frictional force between the annular rib and the retaining ring.

14. A method of manufacturing the syringe according to claim 1, the method comprising: Providing a syringe barrel; Fixing the stopper to the plunger by coupling the attachment member to the plunger distal end; And Positioning the stopper and a portion of the plunger within the chamber of the syringe barrel; Wherein when positioning the stopper and the said portion of the plunger within the chamber, the plunger and the stopper are placed in an initial position, in which the cup member is separated from the barrel distal end.

15. A syringe comprising: A syringe barrel having a barrel proximal end and a barrel distal end and defining a chamber configured to receive a fluid therein; And A plunger assembly capable of axially moving within the chamber of the syringe barrel between a retracted position and an advanced position, the plunger assembly including: A plunger having a plunger proximal end and a plunger distal end, and A stopper fixed to the plunger distal end, the stopper configured to be suctioned to the barrel distal end when the plunger assembly moves to the advanced position; Wherein the stopper is further configured to separate from the plunger and remain suctioned to the barrel distal end when the plunger axially moves back from the advanced position towards the retracted position.

16. The syringe according to claim 15, wherein the stopper comprises: An attachment member configured to be coupled to the plunger distal end; A cup member extending distally from the attachment member, the cup member having a concave shape, wherein the cup member is capable of deflecting between the concave shape and a flat shape; And A nose member extending distally from the attachment member and beyond the cup member, the nose member being positioned within the perimeter of the cup member.

17. The syringe according to claim 16, wherein the distal end of the plunger includes a flanged extension member, and the attachment member of the stopper includes a receiving portion formed therein, and the flanged extension member is coupled to the receiving portion by a press fit connection to fix the stopper to the plunger; and wherein in the case where the stopper is suctioned to the distal end of the barrel, when the plunger is axially moved back from the advanced position to the retracted position, the flanged extension member is pulled out of the receiving portion.

18. The syringe according to claim 16, wherein the syringe barrel includes: A cylindrical outer wall extending between the barrel proximal end and the barrel distal end; An end wall positioned at the barrel distal end;And A nozzle extending distally from the end wall, the nozzle defining an inner cavity through which fluid enters or exits the chamber; Wherein the inner surface of the end wall includes a substantially flat surface.

19. The syringe according to claim 18, wherein, with the plunger assembly in the advanced position, the nose member extends into the mouthpiece and the cup member contacts the end wall and deflects from a concave shape to a flat shape, thereby drawing the stopper towards the end wall of the syringe barrel.

20. The syringe according to claim 15, wherein the syringe barrel includes a retaining ring formed on its inner surface, the retaining ring being located towards the proximal end of the barrel, and wherein the plunger includes an annular rib formed thereon and located towards the proximal end of the plunger, wherein the annular rib is proximal to the retaining ring when the plunger and the stopper are in the retracted position; and wherein, in order to move the plunger and the stopper to the advanced position, the distally directed force applied to the plunger assembly must be greater than the frictional force between the annular rib and the retaining ring.

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