Retaining element for preventing loosening contamination of a partially prefilled syringe

Abstract

An injector assembly comprising a partially pre-filled syringe barrel and a plunger rod provided with one or more retention elements on the plunger rod that prevent the solution from entering the non-sterile area of the syringe when the plunger rod is pulled back. A method of manufacturing a sterilized, partially filled pre-filled syringe assembly is also disclosed.

Description

[0001] Case Analysis

[0002] This invention patent application is a divisional patent application.

[0003] The original application for this divisional patent application is an invention patent application with an international application date of June 24, 2020, international application number PCT / US2020 / 039348, Chinese national application number 202080021347.8, and an invention title of "Retaining element for preventing loosening and contamination of partially pre-filled syringes". Technical Field

[0004] This disclosure relates to syringe assemblies, and more particularly to syringe assemblies having a plunger rod with a retaining element that, for partially prefilled syringes, prevents solution from entering non-sterile areas of the syringe when the plunger rod is pulled back. This disclosure also relates to a method of manufacturing a sterile, partially prefilled syringe assembly. Background Technology

[0005] Some currently available 10 ml syringes may include retaining rings on both the plunger rod and barrel to prevent the stopper and fluid from shifting backward into non-sterile areas. However, due to the distance between the retaining rings on the plunger rod and barrel, currently available 10 ml syringes with retaining rings on both the plunger rod and barrel cannot effectively produce partially filled syringes with prefill volumes ranging from greater than 0 ml to less than 10 ml (e.g., 3 or 5 ml).

[0006] A syringe assembly is also required, which has a plunger rod with a retaining element, which, for partially prefilled syringes, is introduced to prevent solution from entering the non-sterile area of ​​the syringe if the plunger rod is accidentally pulled back. Summary of the Invention

[0007] A syringe assembly and a method of manufacturing the syringe assembly are described. The syringe assembly includes a plunger rod with a retaining element that, for a partially prefilled syringe, prevents solution from entering a non-sterile area of ​​the syringe when the plunger rod is pulled back.

[0008] One aspect of this disclosure relates to a syringe assembly including a barrel, a proximal and distal opening, a plunger rod body disposed within the barrel, and one or more retention elements disposed on the plunger rod. The barrel may include a sidewall having an inner surface defining a chamber for holding a predetermined amount of prefilled fluid. The distal opening includes a distal sidewall having an end extending distally therefrom, the end having a channel through which it communicates fluidly with the chamber. The plunger rod body is disposed within the barrel. The plunger rod may include a distal and a proximal opening, the distal opening including a stopper having a distal surface. One or more retention elements are disposed on the plunger rod, a length from the distal end of the plunger rod, and configured to provide enhanced mechanical interference between the plunger rod and the barrel when a force is applied in the proximal direction to prevent prefilled fluid from entering a non-sterile area of ​​the syringe assembly.

[0009] In one or more embodiments, one or more retaining elements include a plurality of discontinuities disposed on the outer surface of the plunger rod.

[0010] In one or more embodiments, one or more retaining elements extend radially outward toward the inner surface of the cylinder.

[0011] In one or more embodiments, the predetermined amount of prefilled fluid is in the range of 0 ml to 10 ml, preferably 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 6 ml, 7 ml, 8 ml, 9 ml, and 10 ml. In one or more embodiments, the predetermined amount of prefilled fluid is 3 ml. In one or more embodiments, the predetermined amount of prefilled fluid is 5 ml.

[0012] In one or more embodiments, the retaining elements further include: at least one discontinuity disposed on the outer surface of the plunger rod, the discontinuity extending radially outward toward the inner surface of the cylinder; and at least one retaining ring disposed on the inner surface of the cylinder, the retaining ring extending radially inward toward the outer surface of the plunger rod. In one or more embodiments, the at least one discontinuity cooperates with the at least one retaining ring to increase the interference between the plunger rod and the cylinder, thereby generating an increased mechanical force to prevent the plunger rod from moving forward in the proximal direction.

[0013] In one or more embodiments, the movement of the plunger rod in the proximal direction causes interference between the retaining ring disposed on the inner surface of the cylinder and one or more retaining elements of the plunger.

[0014] In one or more embodiments, a portion of the outer surface of the plunger rod has no retaining element.

[0015] In one or more alternative embodiments, one or more retaining elements include a first component having two sidewalls flush with the straight wall of the crossbar, an inclined top surface with a slope in the range of 1% to 100%, one or more flat portions oriented parallel to the longitudinal axis, and a platform portion forming a flat end oriented perpendicular to the longitudinal axis in the inclined top surface.

[0016] In one or more alternative embodiments, one or more retaining elements further include a second component having an inclined wedge that extends radially from the outer edge of the straight wall relative to the straight wall.

[0017] In one or more alternative embodiments, one or more retaining elements further include a second component having an elongated protrusion that slopes from the distal end to the proximal end and extends from the curved wall of the cross bar.

[0018] In one or more alternative embodiments, one or more retaining elements further include a second component having a slot in the sidewall of the cross bar aligned with the plunger rod at a rear position of the retaining element.

[0019] In one or an alternative embodiment, the prefilled fluid is a solution containing saline, heparin, citrate, pharmaceuticals or other drugs or combinations thereof.

[0020] In one or more alternative embodiments, the prefill fluid is a pharmaceutical agent. In one or more alternative embodiments, the prefill fluid is a rinsing solution.

[0021] In one or more embodiments, the syringe assembly is terminally sterilized or has aseptic requirements along the fluid path.

[0022] Another aspect of this disclosure relates to a method of manufacturing a sterile, partially filled, pre-filled syringe assembly. A cartridge is provided, including a sidewall, a proximal opening, and a distal end. The sidewall has an inner surface defining a chamber having a total volume for holding a predetermined amount of pre-filled fluid. The proximal opening has a retaining protrusion, and the distal end includes a distal sidewall having an end extending distally therefrom, the end having a channel therethrough in fluid communication with the chamber. A pre-selected filling volume is provided, wherein the filling volume is significantly smaller than the total volume. A plunger rod is provided according to one or more embodiments described in this disclosure. As described in this disclosure, the plunger rod includes one or more retaining elements disposed on the plunger rod at a distance from the distal end of the plunger rod, the distance being related to the filling volume. The plunger rod is inserted into the cartridge until the retaining elements are in a distal position relative to the retaining protrusion. The cartridge is filled with a predetermined amount of pre-filled fluid to the filling volume, wherein the filling volume is significantly smaller than the total volume. The end of the cartridge is sealed with a sealing element. In one or more embodiments, the sealing element is an end cap. The pre-filled syringe assembly is sterilized. In one or more embodiments, the pre-filled syringe undergoes a final sterilization process in the manufacturing plant via autoclaving or radiation sterilization to create a sterile path for the pre-filled liquid.

[0023] In one or more embodiments, the total volume is approximately 3.33 times the fill volume. In one specific embodiment, the total volume is approximately 10 ml and the fill volume is 3 ml.

[0024] In one or more alternative embodiments, the total volume is approximately twice the fill volume. In one specific embodiment, the total volume is approximately 10 ml and the fill volume is 5 ml. Attached Figure Description

[0025] Figure 1 A transparent top view of a syringe assembly having a barrel and a plunger rod according to one or more embodiments of the present disclosure is shown;

[0026] Figure 2 It shows Figure 1 A partial transparent top view of the interaction between the plunger rod and the barrel of the syringe assembly shown;

[0027] Figure 3 A side view of a plunger rod according to one or more embodiments of the present disclosure is shown;

[0028] Figure 4 It shows Figure 3 A partial bottom perspective view of the plunger rod embodiment shown;

[0029] Figure 5 It shows Figure 3 Partial bottom perspective view of an alternative embodiment of the plunger rod shown;

[0030] Figure 6 It shows Figure 3 A partial bottom perspective view of an alternative embodiment of the plunger rod shown;

[0031] Figure 7 It shows Figure 3 A partial bottom perspective view of an alternative embodiment of the plunger rod shown;

[0032] Figure 8 It shows Figure 3 A partial top perspective view of an alternative embodiment of the plunger rod shown;

[0033] Figure 9 It shows Figure 3 A partial perspective view of an alternative embodiment of the plunger rod shown; and

[0034] Figure 10 This is a flowchart illustrating a method for manufacturing a sterilized, partially filled, pre-filled syringe assembly. Detailed Implementation

[0035] Before describing several exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the details of the construction or process steps set forth in the following description. The invention can have other embodiments and can be practiced or performed in various ways.

[0036] The syringe assembly of this disclosure includes a plunger rod with one or more retaining elements that, for a partially prefilled syringe, prevent solution from entering a non-sterile area of ​​the syringe when the plunger is accidentally pulled back. The syringe assembly of this disclosure includes one or more retaining elements to prevent loosening and contamination of a partially prefilled syringe.

[0037] The syringe assembly according to a first aspect includes a syringe barrel and a plunger rod, the plunger rod having a retaining element or feature located on the plunger rod for interacting with a retaining ring on the syringe barrel. In one or more embodiments, the retaining ring is disposed on an inner surface of the barrel and extends inward into a chamber of the barrel. The cross-sectional width of the inner surface of the syringe barrel at the retaining ring is smaller than the cross-sectional width of the inner surface of the syringe barrel at the remainder of the barrel. In one or more embodiments, the retaining feature is in the form of a mechanical stop. Figure 1 An embodiment of the assembled syringe is shown. Figure 2-9 Some alternative embodiments of the plunger rod used with the syringe barrel are shown separately. References Figure 1-9According to one embodiment, a syringe assembly includes a barrel 10, which includes a sidewall 12, a proximal opening 11, and a distal opening 19. The sidewall 12 has an inner surface 14 defining a chamber 16 for retaining fluid. The distal opening 19 includes a distal sidewall 17 having a distal end 15 extending distally therefrom. The distal end 15 includes a channel 13 through which it is in fluid communication with the chamber 16. Figure 1 As shown, the proximal end 11 of the opening includes a finger flange 20. The sidewall 12 of the cylinder may be cylindrical or may have other shapes.

[0038] like Figure 1 As shown, the end 15 of the cylinder may include a locking Luer-type collar (such as...) that concentrically surrounds the end 15. Figure 1 (shown) or a Luer sliding connector (not shown). In one or more embodiments, the barrel may include a needleless connector. In one or more embodiments, the barrel may include a conventional medical connector. The collar 18 may include an inner surface having at least one thread. Optionally, a needle assembly (not shown) may be provided, comprising a cannula having a proximal end, a distal end, and a lumen therethrough. A hub (not shown) has an open proximal end and a distal end, the open proximal end containing a lumen, and the hub may be attached to the proximal end of the cannula such that the lumen is in fluid communication with the lumen of the hub. The needle assembly (not shown) is removably attached to the end of the barrel by engagement of its end with the hub lumen such that the lumen is in fluid communication with the barrel chamber.

[0039] like Figure 1 and 3 As shown, a plunger rod 30 is provided, comprising a plunger rod body 32 having a proximal end 31 and a distal end 39. The plunger rod 30 is slidably located within a chamber 16 of the cylinder 10 for displacing fluid from the chamber 16. The plunger rod body 32 extends outward from the proximal end 11 of the cylinder opening and is disposed within the chamber 16. The plunger rod 30 includes a thumb press portion 29 located at the proximal end 31 and a plug 40 located at the distal end 39. The plug 40 includes a sealing edge 42 that forms a seal with the inner surface 14 of the cylinder. The shape of the plunger rod can be modified to fit into cylinders with different shaped sidewalls.

[0040] The plunger rod body 32 includes an outer surface 34 that forms a periphery around the plunger rod body 32 and has an axial length extending from a proximal end 31 to a distal end 39. The plunger rod body 32 may include a single beam or structure, which may have a cylindrical or other shape. Figure 1-9 As shown, the main body 32 can be formed by two perpendicularly intersecting beams 37. The beams can have a rectangular cross-section. In the illustrated embodiment, the two intersecting beams 37 intersect to form an outer surface that defines four quadrants 51, 52, 53, 54 (in...). Figure 3(As shown more clearly in the image), these four quadrants face the inner surface 14 of the cylinder and extend along the axial length from the proximal end 31 of the plunger rod to the distal end 39.

[0041] In a preferred embodiment, such as Figure 3 As shown, the plunger body includes two intersecting beams 37, which intersect to form a vertical crossbar 44. The outer surface of the crossbar 44 defines four quadrants in a cross shape. For illustrative purposes, three quadrants 51, 52, and 53 are shown. The vertical crossbar 44 is integrally formed longitudinally with the thumb press portion 29 and the plug engagement portion 28. The plunger body is not limited to a cross shape, and the crossbar 44 does not necessarily have to be vertical or symmetrical. The plunger body 32 may include another geometry that can be internally fitted into the chamber 16 of the syringe barrel 10. For example, the plunger body may be triangular or rectangular.

[0042] A plug engagement 28 with a threaded region is provided adjacent to the distal end 39 for securing the plug. In one or more embodiments, the threaded region of the plug engagement 28 is configured to receive a corresponding thread of the plug. In one specific embodiment, the plunger rod and the plug may be integrally formed or permanently attached. According to one or more embodiments of the present disclosure, the plug engagement 28 is shaped to fit within the plug cavity of the plug and to retain the plug at the distal end of the plunger rod.

[0043] Adjacent to the threaded area is the plunger rod body. The plunger rod body is disposed within the chamber 16 and can move in the proximal and distal directions within the corresponding chamber 16 of the syringe barrel 10.

[0044] The plunger rod body and retaining element can be made of rigid plastic or other materials. Examples of such materials include polypropylene, polyethylene, polycarbonate, and combinations thereof.

[0045] In one or more embodiments, the plug 40 may be integrally formed on the distal end 39 of the plunger rod, or it may be formed as a separate component connected to the distal end 39 of the plunger rod. The distal end 39 of the plunger rod may include the integrally formed plug. Figure 1 As shown, the plug 40 may include a conical distal surface, and the cylinder may include a conical inner surface on its distal wall. The plug 40 is slidably positioned to fluid-tightly engage with the inner surface 14 of the cylinder for drawing fluid into and expelling fluid from the chamber.

[0046] The stopper 40 can be made of any material suitable for providing a seal with the inner surface 14 of the cylinder. For example, the stopper 40 can be made of thermoplastic elastomers, natural rubber, synthetic rubber, or thermoplastic materials and combinations thereof. The stopper 40 can be integrally formed or composed of separate parts of the same or different materials joined together. The plunger rod 30 can be made of a material that is more rigid than the stopper, such as polypropylene, polyethylene, etc. The material should be selected to be compatible with the procedure being used.

[0047] exist Figure 1-9 In the illustrated embodiment, one or more retaining elements 36 are disposed on the outer surface of the body portion 32 of the plunger rod. More specifically, one or more retaining elements are disposed on the outer surface of four quadrants (51, 52, 53). The retaining elements 36 may be integrally formed or provided as separate components that can be added to the plunger rod. In one or more embodiments where the retaining elements 36 are provided as separate components, the plunger rod 30 or cylinder 10 may also include structures for attaching the individual retaining elements 36. In one or more embodiments, the chamber of the cylinder may contain 10 ml of fluid. In one or more embodiments, the prefill fluid is a solution containing saline, heparin, or citrate, or other drugs or agents. In one or more embodiments, the prefill fluid is a flushing solution or agent. The 10 ml chamber 16 of the barrel can be pre-filled with a predetermined amount of solution ranging from 0 ml to 10 ml, preferably 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 6 ml, 7 ml, 8 ml, 9 ml, and 10 ml, wherein a retention element disposed on the plunger rod of this disclosure interacts with a retaining ring on the inner surface of the barrel to prevent the pre-filled solution from entering the non-sterile area of ​​the syringe if the plunger rod is accidentally pulled back by the end user. In one or more embodiments, the chamber 16 of the barrel is pre-filled with 3 ml of solution. In one or more alternative embodiments, the chamber 16 of the barrel is pre-filled with 5 ml of solution. In one or more embodiments, a retaining ring is disposed on the inner surface of the barrel at the proximal end of the barrel. In one or more embodiments, a retaining ring is disposed on the inner surface of the barrel to interact with the retention element of the plunger rod, thereby allowing a predetermined amount of fluid in the range of 0 ml to 10 ml (e.g., 3 ml or 5 ml) pre-filled in the chamber of the barrel, and preventing the pre-filled solution from entering the non-sterile area of ​​the syringe if the plunger rod is accidentally pulled back by the end user.

[0048] like Figure 1As shown, one embodiment of this disclosure relates to a syringe assembly 6 having a barrel and a retaining element 36 disposed at a fixed position along the length of a plunger rod body 32. The chamber of the barrel can be pre-filled with a predetermined amount of fluid in the range of 0 ml to 10 ml, for example, 3 ml or 5 ml. The retaining element 36 is used to prevent the pre-filled solution from leaving the sterile area "A" and entering the non-sterile area "B" located outside the retaining element 36 in the event that the plunger rod is accidentally pulled back to a non-sterile area by the end user.

[0049] In one or more embodiments, the plunger rod 30 includes an integral retaining element 36 along the length of the plunger rod body 32 to control the maximum relative position at which the plunger rod 30 can extend distally from the distal end 19 of the syringe assembly. When the retaining element 36 abuts against a retaining ring within the chamber 16 of the syringe barrel 10, the retaining element 36 prevents the plunger rod from extending further from the distal end 19 of the syringe 6 beyond a desired point, thus preventing pre-filled solution from entering the non-sterile area of ​​the syringe in the event of accidental pull-back of the plunger rod in a partially pre-filled syringe. The position of the retaining element 36 on the plunger rod body 32 is determined by the amount of fluid pre-filled into the syringe barrel 10, such that in the event of accidental pull-back of the plunger rod by the end user, the retaining element 36 prevents pre-filled solution from entering the non-sterile area of ​​the syringe.

[0050] In this disclosure, following convention, the inner direction is the direction perpendicular to the longitudinal axis 5, while the outer direction is the direction perpendicular to the direction away from the longitudinal axis 5.

[0051] like Figure 2 As shown, the syringe barrel 10 includes a chamber 16. In one or more embodiments, the maximum volume of the chamber is 10 ml. In one or more embodiments of this disclosure, the volume of pre-filled fluid in the chamber 16 can range from 0 ml to 10 ml, preferably 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 6 ml, 7 ml, 8 ml, 9 ml, and 10 ml. Within the chamber 16, there is a retaining ring or retaining ring 21 closely adjacent to the proximal end 11 of the syringe barrel 10. The retaining ring 21 extends inwardly into the chamber 16 of the syringe barrel 10. Once the retaining element 36 approaches or abuts the retaining ring 21, the retaining ring 21 prevents the retaining element 36 from translating proximally to prevent pre-filled solution from entering the non-sterile area of ​​the syringe in the event that the plunger rod is accidentally pulled back.

[0052] like Figure 2 and 3As shown, an alternative embodiment of the plunger rod 30 includes one or more retaining elements 36 disposed along the length of the crossbar 44, such that when the plunger rod is positioned in a 10 ml syringe barrel, the plunger rod will limit the pre-filled volume in the syringe chamber 16 to the range of 0 ml to 10 ml (e.g., 3 ml or 5 ml), and prevent the pre-filled solution from entering the non-sterile areas of the syringe in the event that the plunger rod is accidentally pulled back by the end user. More specifically, one or more retaining elements are disposed on the outer surfaces of four quadrants (51, 52, 53). Retaining elements are disposed along the plunger rod body at the far inner end of the crossbar 44. One or more retaining elements are disposed along a certain length of the plunger rod body 32 to allow the user to administer a desired amount of flushing solution or agent in the range of 0 ml to 10 ml (e.g., 3 ml or 5 ml), depending on the position of the retaining elements along the plunger rod. In one or more embodiments, the retaining element of the plunger rod interacts with a retaining ring or retaining ring 21 disposed on the inner surface of the chamber 16 of the syringe barrel 10 and extending radially inward toward the chamber and / or the plunger rod. The retaining ring 21 interacts with a retaining element 36 disposed on the plunger rod 30 to prevent pre-filled solution from entering a non-sterile area of ​​the syringe in the event that the plunger rod is accidentally pulled back by the end user. In such embodiments, the retaining ring 21 forms a narrower cross-sectional width compared to the cross-sectional width formed by the inner surface 14 of the barrel. The inner surface 14 of the barrel has a smaller cross-sectional width at the retaining ring 21.

[0053] For one or more specific embodiments, such as Figure 4 As shown, the mechanical stop of the plunger rod is provided on the cross bar 44 and includes one or more straight walls 41 and curved walls 43.

[0054] like Figure 4 As shown, the retaining element 100 is shaped like a "shark fin". The retaining element 100 is a discontinuous portion along the length of the plunger rod body 32 on the curved wall 43. The retaining element 100 includes an inclined surface 102. The inclined surface 102 is inclined outward toward the proximal end 31 of the plunger rod body 32. The sidewall 104 of the retaining element 100 is flush with the straight wall 41 of the crossbar 44. The retaining element 100 may also have one or more flat portions 106 extending parallel to the longitudinal axis 5. A stop or plateau portion forms the flat end 108 of the retaining element 100 on the inclined surface. The flat end 108 is perpendicular to the longitudinal axis 5.

[0055] In one or more embodiments, the "shark fin" shaped retaining element 100 protrudes radially from the outer surface of four quadrants (51, 52, 53). In one or more embodiments, the thickness of the "shark fin" shaped retaining element 100 is equal to or slightly less than the thickness of the four quadrants (51, 52, 53). In one or more embodiments, the "shark fin" shaped retaining element 100 does not protrude tangentially from the four quadrants (51, 52, 53).

[0056] like Figure 5 and 6 As shown, an alternative embodiment of the plunger rod includes a retaining element 200 having two components disposed and integrated into the wall 43 of the alternating crossbars 44. The retaining element 200 is a discontinuous portion disposed along the length of the plunger rod body 32 on the curved wall 43. The first component 210 of the retaining element is shaped like a "shark fin" and integrated into the curved wall 43 of the crossbars 44, and includes an inclined surface 202. The inclined surface 202 is inclined outward toward the proximal end 31 of the plunger rod body 32. The sidewalls 204 of the retaining element 200 are flush with the straight wall 41 of the crossbars 44. The retaining element 200 may also have one or more flat portions 206 extending parallel to the longitudinal axis 5. A stop or plateau portion forming a flat end 208 of the retaining element 200 is present on the inclined surface. The flat end 108 is perpendicular to the longitudinal axis 5.

[0057] The second component 220 of the retaining element 200 is a discontinuity integrated into the curved wall 43 of the alternating crossbars 44, wherein two of the crossbars 44 have a first component 210 in the form of a "shark fin," and the other two alternating crossbars have a second component 220. The second component 220 is in the shape of an inclined wedge and is integrated into the curved wall 43 of the crossbars 44. The second component 220 includes an inclined surface 222 that slopes outward toward the proximal end 31 of the plunger rod body 32. The retaining element 200 may also have one or more flat portions 226 extending parallel to the longitudinal axis 5. The sidewalls 224 of the second component 220 project outward from the midplane and extend inward to the straight wall 41 of the crossbars 44 to "enclose" the crossbars 44 of the plunger rod body 32. Similar to the inclined surface 222, the sidewalls 224 of the second component 220 slope outward toward the proximal end 31 of the plunger rod body 32. The inclined surface 222 and the sidewall 224 have a stop portion of the flat end 228 of the second part 220 that forms the retaining element 200.

[0058] Within the main body of the rod plunger, the entire plunger rod body 32 may utilize only a single embodiment or a combination of the various embodiments of the retaining elements 100 and 200.

[0059] like Figure 7As shown, an alternative embodiment of the plunger rod includes a retaining element 300 having two components disposed and integrated into alternating crossbars. The retaining element 300 is a discontinuity along the length of the plunger rod body 32 on a curved wall 43. A first component 310 of the retaining element is shaped like a "shark fin" and integrated into the curved wall 43 of the crossbar 44, and includes an inclined surface 302. The inclined surface 302 is inclined outward toward the proximal end 31 of the plunger rod body 32. A sidewall 304 of the first component 310 is flush with the straight wall 41 of the crossbar 44. The first component 310 may also have one or more flat portions 306 extending parallel to the longitudinal axis 5. A cut-off or plateau portion forms a flat end 308 of the first component 310 within the inclined surface. The flat end 108 is perpendicular to the longitudinal axis 5.

[0060] The second component 320 of the retaining element is shaped like a "shark's tail" and integrated into the curved wall 43 of the alternating crossbars 44. The second component 320 includes an inclined surface 322. The inclined surface 322 is inclined outward toward the proximal end 31 of the plunger rod body 32. The sidewall 329 of the second component 320 protrudes outward from the crossbars 44 and is inclined outward toward the proximal end 31 of the plunger rod body 32, aligned with the inclined surface 322. The retaining element 300 may also have one or more flat portions 306 extending parallel to the longitudinal axis 5. Cut-off portions forming the flat ends 328 of the second component 320 are present in the inclined surface 322 and the sidewall 329. The flat ends 328 are perpendicular to the longitudinal axis 5.

[0061] like Figure 8 As shown, an alternative embodiment of the plunger rod includes a retaining element 400 having two components disposed and integrated into alternating crossbars. The retaining element 400 is a discontinuity along the length of the plunger rod body 32 on a curved wall 43. A first component 410 of the retaining element is teardrop-shaped and integrated into the curved wall 43 of the crossbar 44, and includes a beveled surface 402. The beveled surface 402 is inclined outward toward the distal end 39 of the plunger rod body 32. The opposite beveled design provides resistance to the beveled surface 402 when it frictionally engages with the retaining ring 21, and prevents prefilled solution from entering the non-sterile area of ​​the syringe when the plunger rod is pulled back. This results in cessation of proximal translation of the plunger rod 30 relative to the syringe barrel 10. The sidewall 404 of the retaining element 400 is flush with the straight wall 41 of the crossbar 44.

[0062] In one or more embodiments, the first element 410 protrudes radially from the outer surface of the four quadrants (51, 52, 53). In one or more embodiments, the thickness of the first element 410 is equal to or slightly less than the thickness of the four quadrants (51, 52, 53). In one or more embodiments, this type of first element 410 does not protrude tangentially from the four quadrants (51, 52, 53).

[0063] The second component 420 of the retaining element 400 is shaped like a submarine and integrated into the curved wall 43 of the alternating crossbars 44, and includes a sloping surface 422. The sloping surface 422 of the second component 420 is sloping outward toward the distal end 39 of the plunger rod body. The sloping surface 422 is also sloping outward toward the distal end 39 of the plunger rod body 32. The outward sloping of the sloping surface 422 of the second component 420 provides resistance to the sloping surface 422 when the end user accidentally pulls back the plunger rod, as the sloping surface 422 frictionally engages with the retaining ring 21. This causes cessation of proximal translation of the plunger rod 30 relative to the syringe barrel 10. The second component 420 also includes a sidewall 428 that extends inward into the crossbars 44. In one or more embodiments, the second component 220 projects tangentially relative to the curved wall 43. In one or more embodiments, the second component 220 also contacts and encloses a portion of the crossbars 44 in which it resides.

[0064] In one or more embodiments, a first part 410 of retaining element and a second part 420 of retaining element are disposed on alternating crossbars 44, wherein two of the crossbars 44 have the first part 410 and two of the crossbars 44 alternately have the second part 420.

[0065] In one or more embodiments, the plunger rod 30 may include a combination of retaining elements having or not having walls flush with the straight walls of the crossbars.

[0066] One or more embodiments of the plunger rod with retaining element 400 provide the end user with an extended time period to stop the pull-back motion when resistance increases.

[0067] Figure 9 An alternative embodiment of the plunger rod is shown. For example... Figure 9As shown, the retaining element 500 is shaped like a "shark fin". The retaining element 500 is a discontinuity along the length of the plunger body 32 on the curved wall 43. The retaining element 500 includes an inclined surface 502. The inclined surface 502 is inclined outward toward the proximal end 31 of the plunger body 32. The sidewall 504 of the retaining element 500 is flush with the straight wall 41 of the crossbar 44. The retaining element 500 may also have one or more flat portions 506 extending parallel to the longitudinal axis 5. A stop or plateau portion forming the flat end 108 of the retaining element 100 is present on the inclined surface. The flat end 508 is perpendicular to the longitudinal axis 5. In one or more embodiments, the retaining element 500 also includes a plurality of tangential ribs 503 disposed on the inclined surface 502.

[0068] like Figure 9 As shown, a slot 60 is provided on the inner side of the retaining element 500 on the multiple crossbars 44 along the plunger rod 30. The slot allows the retaining element 500 to deflect in the inward and outward directions. The slot 60 allows the retaining element 500 and the surface in which the retaining element is integrated to flex. This increased flexibility allows the plunger rod 30 to be assembled within the syringe barrel 10. To assemble the medical syringe 6, the distal end of the plunger rod 30 is inserted into the proximal end 11 of the syringe barrel 10. As the plunger rod enters the syringe barrel, the retaining ring 21 within the chamber 16 of the syringe barrel 10 applies force to the inclined surface 502 of the retaining element 500. The slot 60 on the straight wall 41 of the crossbars 44 allows the retaining element 500 to deflect in the inward direction. Once the flat end 508 of the retaining element 500 passes the retaining ring 21 in the syringe barrel 10, the retaining element 500 quickly returns from its deflected position, producing an audible "click" sound when the assembly of the medical syringe 6 is complete.

[0069] In one or more embodiments, a plunger rod having any combination of retaining elements described herein may also include slots 60 in a plurality of crossbars 44.

[0070] like Figure 1-9 As shown, multiple retaining elements can be arranged along the axial length of the plunger rod, and can be arranged at predefined intervals along the axial length. In one specific embodiment, the predefined intervals are equidistant. The multiple retaining elements can be arranged along the axial length of the plunger rod, which is determined by the amount of prefilled solution in the range of 0 ml to 10 ml (e.g., 3 ml or 5 ml), thereby preventing the stopper from being pulled back to a point in the non-sterile area behind the original position where the prefilled solution can enter the back of the stopper rib.

[0071] In one or more embodiments, one or more retaining elements 36 may be formed peripherally along a section of the outer surface of the plunger rod, while the remaining sections of the outer surface have no retaining elements.

[0072] When a force caused by an accidental pull by the end user is applied to the plunger rod in the proximal direction, one or more retaining elements 36 of the plunger rod body 32 interact with the retaining ring 21 of the syringe barrel.

[0073] In operation, when used with the plunger rod described herein, the syringe assembly is prefilled with a flushing solution or agent using known methods. The prefilled syringe undergoes a final sterilization process at the manufacturing plant via autoclaving or radiation sterilization to create a sterile path for the prefilled fluid. In one or more embodiments, the flushing solution can be any solution designed to flush or maintain the performance of the vascular access device (VAD). Exemplary flushing solutions include saline flushing solutions and / or heparin lock flushing solutions. These solutions are known in the art and are readily available. An example of a saline flushing solution is 0.9% sodium chloride for injection (USP). An example of a heparin lock flushing solution is 0.9% sodium chloride containing 100 USP units of sodium heparin per milliliter or 10 USP units of sodium heparin per milliliter. Once assembled, the syringe assembly is available for use by the end user to administer the prefilled agent or flush the VAD (such as a catheter in an intravenous infusion kit) by providing distal force. To prevent accidental pull-back, the retaining features described in this disclosure prevent the stopper from being pulled back to a point in the non-sterile area behind the original position of the stopper rib.

[0074] According to one or more embodiments, one or more retaining elements 36 disposed on the plunger rod are configured to interfere with or create enhanced mechanical interference with the syringe barrel during proximal movement of the plunger rod. If the user applies an unexpected force to the plunger rod in the proximal direction, the change in mechanical force between the plunger rod and the barrel will impede, slow down, or stop the movement of the plunger rod.

[0075] Another aspect of this disclosure relates to a method for manufacturing a sterilized, partially filled, pre-filled syringe assembly. Figure 10 An exemplary manufacturing method 600 is illustrated. Reference numerals are used to describe the various components described below. Figure 1-9 The components shown are consistent. For example... Figure 10 As shown in step 610, provide as follows Figure 1 The illustrated cylinder 10 includes a sidewall 12, a proximal opening 11, and a distal opening 19. The sidewall 12 has an inner surface 14 defining a chamber 16 having a total volume for holding a predetermined amount of pre-filled fluid. The proximal opening 11 has a retaining protrusion. The distal opening 19 includes a distal sidewall 17 having an end extending distally therefrom, the end having a channel through which it is in fluid communication with the chamber. Figure 10 As shown in step 620, a certain filling volume is pre-selected, wherein the filling volume is significantly smaller than the total volume. For example... Figure 10As shown in step 630, the following are provided: Figure 1-9 A plunger rod 30 of one or more embodiments is shown. The plunger rod 30 includes a distal end, a plug, and a proximal end. The plunger rod includes one or more retaining elements as described in this disclosure, disposed on the plunger rod at a distance from the distal end of the plunger rod, said distance being related to the filling volume. One or more retaining elements 36 are configured to provide enhanced mechanical interference between the plunger rod 30 and the retaining protrusion of the cylinder 10. Figure 10 As shown in step 640, the plunger rod is inserted into the cylinder 10 until the retaining element is in a distal position relative to the retaining protrusion. Figure 10 As shown in step 650, a predetermined amount of pre-filled fluid is filled into the cylinder 10 to the filling volume, wherein the filling volume is significantly smaller than the total volume. Figure 10 As shown in step 660, the end of the cylinder is sealed with a sealing element. In one or more embodiments, the sealing element is an end cap. Figure 10 As shown in step 670, the pre-filled syringe assembly is sterilized. In one or more embodiments, the pre-filled syringe undergoes a final sterilization process in the manufacturing plant via autoclaving or radiation sterilization to create a sterile path for the pre-filled liquid. In one or more embodiments, the sterilization step of the pre-filled syringe assembly occurs before the plunger rod is inserted into the barrel, until the retention element is in a distal position relative to the retaining protrusion.

[0076] In one or more embodiments, the total volume is approximately 3.33 times the fill volume. In one specific embodiment, the total volume is approximately 10 ml and the fill volume is 3 ml.

[0077] In one or more alternative embodiments, the total volume is approximately twice the fill volume. In one specific embodiment, the total volume is approximately 10 ml and the fill volume is 5 ml.

[0078] In one or more embodiments, one or more retaining elements include a first component having two sidewalls flush with the straight wall of the crossbar, an inclined top surface with a slope in the range of 1%-100%, one or more flat portions oriented parallel to the longitudinal axis, and a platform portion forming a flat end oriented perpendicular to the longitudinal axis in the inclined top surface, such as... Figure 3 and 4 As shown.

[0079] In one or more alternative embodiments, one or more retaining elements further include a second component having an inclined wedge that extends radially from the straight wall 41 relative to the outer edge of the straight wall, such as... Figure 5-7 As shown.

[0080] In yet another alternative embodiment, one or more retaining elements further include a second component having an elongated, oval-shaped projection that slopes from the distal end to the proximal end and extends from the curved wall of the crossbar, such as Figure 8 As shown.

[0081] In yet another alternative embodiment, one or more retaining elements further include a second component having a slot in the sidewall of the crossbar, the slot being aligned along the plunger rod at a rear position of the retaining element, such as... Figure 9 As shown.

[0082] In one or more alternative embodiments, the retaining protrusion is a disc, a washer, or an O-ring.

[0083] Throughout this specification, references to "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" mean that a particular element, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in one embodiment" throughout this specification does not necessarily refer to the same embodiment of this disclosure. Furthermore, in one or more embodiments, a particular element, structure, material, or characteristic may be combined in any suitable manner.

[0084] Although the disclosure herein has been described with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of this disclosure. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatus of this disclosure without departing from the spirit and scope of this disclosure. Therefore, this disclosure is intended to include modifications and variations within the scope of the appended claims and their equivalents.

Claims

1. A syringe assembly comprising: A cylinder includes sidewalls having chambers defined by their inner surfaces for holding a predetermined volume of pre-filled fluid, wherein the predetermined volume of the pre-filled fluid is significantly smaller than the total volume of the cylinder. The opening has a proximal end and a distal end, the distal end including a distal sidewall having an end extending distally therefrom, the end having a channel through which it is in fluid communication with the chamber; A plunger rod disposed within the cylinder, the plunger rod including a distal end and a proximal end, a plunger rod body extending from the proximal end to the distal end, the distal end including a plug having a distal side, the plunger rod being formed by two perpendicularly intersecting beams intersecting to form an outer surface, the outer surface defining four quadrants facing the inner surface of the cylinder and extending axially from the proximal end to the distal end of the plunger rod; as well as One or more retention elements are disposed on the plunger rod at a distance from the distal end of the plunger rod, the retention elements being configured to provide enhanced mechanical interference between the plunger rod and the barrel when force is applied in the proximal direction to prevent prefilled fluid from entering a non-sterile area of ​​the syringe assembly, wherein the one or more retention elements include a first part and a second part disposed on and integrated into the alternating crossbars, the first part of the retention element being teardrop-shaped and integrated into the curved wall of the crossbars, and including a first inclined surface that is inclined outward toward the distal end of the plunger rod body, the second part of the retention element being submarine-shaped and integrated into the curved wall of the alternating crossbars, and including a second inclined surface that is inclined outward toward the distal end of the plunger rod body.

2. The syringe assembly according to claim 1, wherein, At least one of the first and second inclined surfaces frictionally engages with the retaining ring to prevent prefilled solution from entering the non-sterile area of ​​the syringe when the plunger rod is accidentally pulled back by the end user.

3. The syringe assembly according to claim 1, wherein, The first component extends radially from the outer surfaces of the four quadrants.

4. The syringe assembly of claim 1, wherein, The thickness of the first component is equal to or slightly less than the thickness of the four quadrants.

5. The syringe assembly according to claim 1, wherein, The first component does not protrude tangentially from the four quadrants.

6. The syringe assembly of claim 1, wherein, The second component also includes a sidewall that extends inward into the crossbar.

7. The syringe assembly of claim 1, wherein, The second component protrudes tangentially relative to the curved wall.

8. The syringe assembly of claim 1, wherein, The second component contacts and encloses a portion of the crossbar where the second component is located.

9. The syringe assembly of claim 1, wherein, Two of the intersecting bars have a first component, and the other two alternating intersecting bars have a second component.

10. The syringe assembly of claim 1, wherein, The total volume is approximately 3.33 times the filling volume.

11. The syringe assembly of claim 10, wherein, The total volume is approximately 10 ml, and the filling volume is 3 ml.

12. The syringe assembly of claim 1, wherein, The total volume is approximately twice the filling volume.

13. The syringe assembly of claim 12, wherein, The total volume is approximately 10 ml, and the filling volume is 5 ml.

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