Syringe plunger rod, syringe barrel, and syringe

Abstract

A syringe plunger rod (100) extending along a central longitudinal axis (A) includes a distal sealing plug (102) for sealing engagement with the syringe barrel (200) and a proximal elongated shaft (103) with a proximal end (104) adapted to receive a force applied along the longitudinal axis (A). The sealing plug (102) is made of a resilient material, and the sealing plug distal face (105) includes a concentric step (106) that is laterally elevated. A syringe barrel (200) is also provided. The syringe barrel (200) includes a needle hub (204) with a longitudinal needle press-fit channel (206). The press-fit channel (206) is flush with the distal plunger socket wall (202) such that the press-fit channel (206) extends proximally into the volume (V). A hollow needle (205) is press-fit into the press-fit channel (206).

Description

[Technical Field]

[0001] The present invention relates to a syringe plunger rod, a syringe barrel, and a syringe comprising a syringe plunger rod and a syringe barrel. [Background technology]

[0002] Injections are one of the most common medical procedures, with 22 billion injections administered worldwide each year. During 2021, mass vaccinations against Covid-19 will require even greater quantities of syringes to administer the shots.

[0003] Syringes known in the art can be pre-filled syringes that are delivered with medicines / vaccines already in place, or conventional syringes that are empty and then filled with the drug to be administered to the patient. Pre-filled syringes are made of either glass or polymer materials. However, their manufacturing process is not cost-effective. Furthermore, glass syringes are more expensive than polymer syringes.

[0004] Conventional syringes are used with a hypodermic needle, which is connected to the tip of the syringe before use. While they are cheaper to manufacture than prefilled syringes, the medication barrel / hypodermic needle cannot be completely emptied, meaning that a residual amount of medication is lost with each injection. This leads to the loss of medication, including expensive active ingredients. To compensate for medication loss in the syringe's dead space, vials holding medication are filled with a 20% surplus. Furthermore, due to the dead space of conventional syringes, air must be removed (in the dead space before filling the needle) before injection to prevent air embolism. This is a time-consuming procedure that wastes medication.

[0005] Furthermore, multiple uses of the same syringe to inject multiple people can lead to the spread of several infectious diseases. It is estimated that syringe misuse causes more than 2 million patients and users to become infected with serious blood-borne diseases such as HIV, Hepatitis B, and Hepatitis C each year. The majority of these injections are administered using conventional syringes or conventional prefilled syringes that are commercially available.

[0006] Already in 2015, the World Health Organization (WHO) set a deadline that all syringes worldwide should be replaced by so-called "smart syringes" such as auto-disable (AD) syringes by 2020. Smart syringes prevent syringe reuse and therefore reduce the spread of the above-mentioned infectious diseases.

[0007] However, commercially available smart syringes also suffer from some of the drawbacks mentioned above, such as the inability to completely empty the syringe barrel of medicine.

[0008] Therefore, there is a need for an improved syringe that is inexpensive to manufacture and reduces the amount of medication remaining in the barrel after injection. Summary of the Invention

[0009] Accordingly, the present invention preferably aims to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and drawbacks in the art, singly or in any combination, and solves at least the above-mentioned problems by proposing a syringe plunger rod extending along a central longitudinal axis, comprising: a distal plunger top having a sealing plug for sealing engagement with a syringe barrel, a proximal elongated shaft having a proximal end adapted to receive a force applied along the axis, wherein the sealing plug is made of an elastic material, and a distal surface of the sealing plug comprises concentric steps, the concentric steps climbing laterally.

[0010] Also provided is a syringe barrel extending along a central longitudinal axis, the syringe barrel comprising: a barrel cylinder defining a volume adapted to contain a medicament, the barrel cylinder having a distal plunger socket wall and a tubular wall extending proximally from the distal plunger socket wall; a needle hub extending distally from the barrel cylinder; and a hollow needle extending distally from the needle hub, the needle hub including a longitudinal needle press-fit channel, the press-fit channel being flush with the distal plunger socket wall such that the press-fit channel extends proximally into the volume, and the hollow needle being press-fit into the press-fit channel.

[0011] A syringe including such a syringe plunger rod and a syringe barrel is also provided.

[0012] Further advantages will become apparent from the detailed description and the appended dependent claims. [Brief explanation of the drawings]

[0013] These and other aspects, features and advantages of the present invention will become apparent and elucidated from the following description of embodiments of the invention when taken in conjunction with the accompanying drawings.

[0014] [Figure 1] 1 is a longitudinal cross section of a syringe. [Figure 2] 1 shows a cross section of a syringe according to the present invention in detail and in its position of use. DETAILED DESCRIPTION OF THE INVENTION

[0015] To enable those skilled in the art to practice the invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The embodiments do not limit the invention, which is limited only by the appended claims. Furthermore, the terminology used in the detailed description of specific embodiments illustrated in the accompanying drawings is not intended to limit the invention.

[0016] Referring to FIG. 1 , a syringe plunger rod 100 is disclosed. The syringe plunger rod 100 extends along a central longitudinal axis A. The syringe plunger rod 100 includes a distal plunger top 101. The distal plunger top 101 includes a sealing plug 102. The sealing plug 102 seals against the syringe barrel 200 during use to form a syringe 300. An elongated shaft 103 is provided adjacent the sealing plug 102. A push plate 104 is provided at the proximal end of the elongated shaft 103. The push plate 104 extends substantially transverse to the longitudinal axis A. The push plate 104 is adapted to receive a force applied along the axis A such that, during use, the syringe plunger rod 100 is displaced relative to the barrel 200.

[0017] According to FIG. 2 , the present invention also provides a syringe barrel 200. The syringe barrel 200 extends along a longitudinal axis A. The syringe barrel 200 includes a barrel cylinder 201 defining a volume V adapted to contain a medicament. The barrel cylinder 201 has a distal plunger socket wall 202 and a tubular wall 203 extending proximally from the distal plunger socket wall 202. A needle hub 204 extends distally from the barrel cylinder 201. A hollow needle 205 extends distally from the needle hub 204. The needle hub 204 includes a longitudinal needle press-fit channel 206. The press-fit channel 206 is flush with the distal plunger socket wall 202 such that the press-fit channel 206 extends proximally to the volume V, and thus the press-fit channel 206 is recessed within the volume V. The hollow needle 205 is press-fit into the press-fit channel 206. The wall thickness of the needle hub 204 around the press-fit channel 206 is preferably 0.5 to 1.5 mm, which provides elasticity and flexibility during the needle loading process. Furthermore, the longitudinal length of the press-fit channel 206 is preferably 1.5 to 4.5 mm. The relatively thin thickness enhances the seal between the hollow needle 205 and the needle hub 204 and reduces irregularities and fragility therein. Furthermore, this minimizes resistance in the seal and provides a maximum contact diameter between the hollow needle 205 and the needle hub 204. Furthermore, this provides elasticity to the needle hub wall, which facilitates and assists in press-fitting the hollow needle 205 into the needle hub 204.

[0018] The sealing plug 102 is made from a resilient material. Disposed at the distal end of the sealing plug 102 is a sealing plug distal surface 105. The sealing plug distal surface 105 comprises concentric steps 106. In this context, the term "concentric" means extending about a central axis A, and does not necessarily mean, but does not exclude, the same step length, the same step height, being exactly circular, being exactly co-centered, circumferential, etc. In the embodiment disclosed in FIG. 2, this means that the different steps 106 are disposed at different radial distances from the central axis A and extend about the central axis A.

[0019] 2, the number of concentric steps is 5. However, this number may vary depending on the size of the syringe into which the syringe plunger rod 100 is placed and / or the medication being injected. The number of steps 106 may be between 2 and 50, for example, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0020] The steps 106 rise laterally, i.e., toward the circumference of the sealing plug 102. As the syringe plunger rod 100 is displaced relative to the barrel 200, the sealing plug distal face 105 eventually abuts the distal plunger socket wall 202 of the barrel 200. As the syringe plunger rod 100 is displaced relative to the barrel 200, the sealing plug 102 slides against the tubular wall 203 of the barrel 200. Because the steps 106 rise laterally, the outermost steps 106 abut the distal plunger wall 202 first, forcing the injected liquid toward the center. In this way, the final portion of the injected medication, such as a vaccine or viscous medication, is forced from the periphery toward the center into the needle channel. Due to the resiliency of the sealing plug 102, the sealing plug 102 deforms with the additional force in the distal direction, causing the central step of the outermost step 106 to displace relative to the barrel 200 and abut the distal plunger socket wall 202. In this way, the liquid to be injected is forced further toward the center. The same relative motion with respect to the barrel 200 is repeated for each step 106, forcing the liquid toward the center and into the hollow needle 205 of the barrel 200. In this way, the amount of air trapped at the interface of the sealing plug 102 and the plunger socket wall 202 can be reduced.

[0021] The height of each step may be 0.01 mm to 1 mm. The number of steps 106 may vary from 2 to 50. Parameters for adjusting the step height and number of steps may be the inner diameter of the barrel 200 and the E module of the sealing plug 102. The width of the steps 106 may also be varied.

[0022] At the center, i.e., below the hollow needle 205, the sealing plug distal surface 105 is provided with a central plateau 107 from which concentric steps rise laterally. In this manner, the central plateau 107 is located proximally just below the hollow needle 205. In this manner, the sealing plug distal surface 105 is configured such that a minimal amount of injected fluid is trapped within the barrel 200, as the plateau 107 can be located flush with the proximal end of the hollow needle 205.

[0023] The sealing plug distal surface 105 is generally conical such that the outermost concentric step 106 is located proximate to the distal end point of the sealing plug 102, such as plateau 107. This further assists in forcing the injected fluid into the needle 205, as there is a distal force component due to the injection force being directed distally.

[0024] Returning to the syringe barrel 200, the needle hub 204 includes a distal needle hub opening 207 that tapers proximally toward the central longitudinal axis A and the center of the needle hub opening 207. The hollow needle 205 has a needle proximal end 208 that has an external taper or radius that tapers / rounds toward the central longitudinal axis A. The proximal needle end 208 of the hollow needle 205 is substantially flush with the distal plunger socket wall 202. The proximal end 208 of the hollow needle 205 engages the needle hub 204. The internal taper of the needle hub 204 guides the hollow needle 205 into the needle hub 204 when the hollow needle 205 is displaced into the press-fit channel 206 for attachment to the needle hub 204. Additionally, the taper reduces friction between the hollow needle 205 and the needle hub 204, facilitating attachment of the hollow needle 205. If the inner taper of the needle hub 204 and the outer taper of the hollow needle 205 were straight and not tapered, it would be difficult to fit the needle proximal end 208 into the needle hub opening 207. Furthermore, high pressure is exerted between the outer surface of the needle proximal end 208 and the needle hub 204, such as the press-fit channel 206. The rounded outer taper of the needle proximal end 208 is advantageous because it reduces the risk of the hollow needle 205 peeling material from the needle hub 204 during the attachment process. Sharp edges could scratch the needle hub 204, potentially causing plastic particles to become dislodged from the needle hub 204 and mix with the medication being injected through the hollow needle 205. The needle hub opening 207 and the remainder of the needle hub 204 are formed from a single mold core, injection molded or machined to form the needle hub 204 with its internal taper, so that there is no shoulder or other obstruction to the hollow needle 205 when inserted into the needle hub opening 207.

[0025] Because the hollow needle 205 is press-fitted into the needle hub 204, no adhesive or glue is required to attach the hollow needle 205 to the needle hub 204. The use of adhesives to connect the needle to the syringe is very common in pre-filled syringes known in the art, both glass and / or polymer syringes. The needle can be molded into the syringe barrel during the injection molding process used to form the polymer syringe. However, this is not a cost-effective needle integration technique compared to the press-fit attachment process used in the syringes described herein. Furthermore, all types of adhesives used in syringes (such as epoxy resins or glues) pose quality risks. Viscous adhesives can reach the drug / vaccine flow path in the syringe and thereby damage the syringe. Press-fitting eliminates the need for adhesives. Also, for example, when using a Luer-slip syringe with a hypodermic needle, there is always a risk that the hypodermic needle, once attached, may leak or become dislodged during the injection process. Finally, even when using a smart syringe with a hypodermic needle, it is possible to remove the hypodermic needle after injection and reuse the hypodermic needle with another barrel, which contributes to the spread of infection. In the barrel 200 described herein, this problem is mitigated because the needle 205 is securely attached to the needle hub 204.

[0026] After hollow needle 205 is press-fit into press-fit channel 206, it is preferred that needle proximal end 208 be at a proximal-distal level with plunger socket wall 202 to minimize dead space within syringe 300. Hollow needle 205 can have an inner diameter of approximately 0.15 to 0.2 mm.

[0027] Syringe barrel 200 is made from a polymeric material, preferably a plastic selected from cycloolefin polymer (COP), cycloolefin copolymer (COC), or polypropylene (PP). These polymers are particularly preferred because they have beneficial tensile strength properties that facilitate press-fitting of hollow needle 205 in needle hub 204.

[0028] A needle cover (not shown) may be disposed on a cover flange 209, which extends distally and is disposed laterally of the needle hub 204. The cover flange 209 is configured as a cylinder around the needle hub 204 such that the needle cover can be slid into engagement onto the cover flange 209. The cover protects the user from the hollow needle 205. The cover flange 209 being separated from the needle hub 204 allows the cover to be sized separately from the size of the needle hub 204, and vice versa. Additionally, the cover flange 209 may be made thinner, with dimensions that can increase flexibility, to facilitate placement of the cover onto the cover flange 209.

[0029] When the hollow needle 205 is placed in place within the needle hub 204, the hollow needle 205 has a plurality of circumferential recesses 210, such as radial grooves, on its outer surface facing the interior cavity wall of the needle hub 204. The circumferential recesses 210 increase the connection strength between the hollow needle 205 and the needle hub 204. This technique is simple and cost-effective for securely attaching the hollow needle 205 within the needle hub 204. The circumferential recesses 210 each have a V- or U-shaped cross-section, and when the hollow needle 205 is press-fit into the needle hub 204, the edges of the recesses 210 engage with the polymer material of the needle hub 204. This is due to the fact that all polymer materials have limited creep characteristics during press-fitting. When pressed-fit, pressure, strain, and tension are applied to the solid polymer needle hub 204, causing it to initiate cold flow, allowing the circumferential recesses 210 with their edges to engage with the needle hub 204. Thus, increased adhesion of the hollow needle 205 on the needle hub 204 is achieved.

[0030] The needle hub opening 207 may be melted to abut the outer surface of the hollow needle 205 after insertion of the hollow needle 205. This technique allows for a lower press fit and can also be used with needles without the circumferential recess 210. The melted needle hub opening 207, together with the circumferential recess 210, provides a stronger, more secure attachment of the needle 205 in the needle hub 205.

[0031] Barrel 200 has a volume V configured to contain a medication, vaccine, or any other type of medicinal liquid or solution to be administered to a patient. The medication may be in liquid form to be injected into the patient or user.

[0032] 1 is disposed within barrel 200. Plunger rod 100 extends along tubular wall 203 and axis A.

[0033] The sealing plug 102 is adapted to fluid-tightly engage the tubular wall 203 of the barrel 200. The fluid-tight engagement with the tubular wall 203 of the barrel 200 prevents the drug or liquid contained within the barrel 200 from leaking out of the syringe 300 in any other direction other than through the hollow needle 205.

[0034] Figures 2a to 2f show the operation of a syringe 300 comprising the plunger rod 100 and barrel 200 of Figure 1. Figures 2a to 2f show a cross section of the syringe 100 in the use position.

[0035] 2a, plunger rod 100 is pushed distally, and sealing plug 102 is displaced along tubular wall 203 of barrel 200. Sealing plug distal face 105 does not yet abut plunger socket wall 202.

[0036] 2b, the periphery of the sealing plug distal surface 105, i.e., the outermost disposed step 106, abuts the outermost portion of the plunger socket wall. Thus, the fluid / medication contained in volume V of the syringe 100 is forced into the center of the outermost step 106.

[0037] In Figure 2c, the plunger rod 100 is advanced further distally compared to the position in Figure 2b, and the elastic properties of the sealing plug 102 cause it to deform to conform to the shape of the plunger socket wall 202. Thus, the fluid / medication contained in volume V of the syringe 100 is forced into the center of the step 106, which is second from the periphery.

[0038] In Figure 2d, the plunger rod 100 is advanced further distally compared to the position of Figure 2c, and the elastic properties of the sealing plug 102 cause it to further deform to conform to the shape of the plunger socket wall 202. Thus, the fluid / medication contained in volume V of the syringe 100 is forced into the center of the step 106, which is third from the periphery.

[0039] In Figure 2e, the plunger rod 100 is again advanced further distally compared to the position of Figure 2d, and the elastic properties of the sealing plug 102 cause it to further deform to conform to the shape of the plunger socket wall 202. Thus, the fluid / medication contained in volume V of the syringe 100 is forced into the center of the step 106, which is the fourth from the periphery.

[0040] In Figure 2f, plunger rod 100 is advanced even further distally compared to the position of Figure 2d, and the elastic properties of sealing plug 102 cause it to further deform to conform to the shape of plunger socket wall 202. Thus, the fluid / medication contained in volume V of syringe 100 is forced into the center of step 106, which is the fifth from the periphery. At this position, central plateau 107 closes press-fit channel 206, thereby emptying the entire volume V of barrel 200.

[0041] The sealing plug 102 is made from a resiliently flexible material, preferably a polymeric material selected from a thermoplastic elastomer or a natural or synthetic rubber material. As force is applied in the distal direction, a larger portion of the sealing plug distal surface 105 contacts the plunger socket wall 202.

[0042] Furthermore, although the present invention has been described primarily with reference to certain embodiments, it will be readily apparent to those skilled in the art that other embodiments than those disclosed above are equally possible within the scope of the present invention as defined by the appended claims.

[0043] In the claims, the term "comprises" does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. In addition, although individual features may be included in different claims, these may be advantageously combined, and their inclusion in different claims does not imply that a combination of features is infeasible and / or advantageous. In addition, the use of the singular does not exclude a plurality. The use of terms such as "a," "an," "first," and "second" does not exclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way.

Claims

1. A syringe plunger rod (100) extending along a central longitudinal axis (A), a distal sealing plug (102) for sealingly engaging the syringe barrel (200); a proximal elongate shaft (103) having a proximal end (104) adapted to receive a force applied along said longitudinal axis (A); Equipped with A syringe plunger rod (100) wherein the sealing plug (102) is made of a resilient material, the sealing plug distal surface (105) comprises a concentric step (106), the concentric step (106) being laterally elevated.

2. 2. The syringe plunger rod (100) of claim 1, wherein the number of concentric steps (106) is 2, 3, 4, 5, 6, 7, 8, 9, or 10.

3. 3. The syringe plunger rod (100) of claim 1 or 2, wherein the sealing plug distal surface (105) comprises a central plateau (107) from which the concentric steps (106) rise laterally.

4. 4. The syringe plunger rod (100) of claim 1, wherein the sealing plug distal surface (105) is generally conical such that the outermost concentric step (106) is positioned proximate to the distal end point of the sealing plug (102).

5. A syringe barrel (200) extending along a central longitudinal axis (A), said syringe barrel (200) comprising: a barrel cylinder (201) defining a volume (V) adapted to contain a medicament, the barrel cylinder (201) having a distal plunger socket wall (202) and a tubular wall (203) extending proximally from the distal plunger socket wall (202); a needle hub (204) extending distally from the barrel cylinder (201); a hollow needle (205) extending distally from said needle hub (204); Equipped with the needle hub (204) comprises a longitudinal needle press-fit channel (206), the press-fit channel (206) being flush with the distal plunger socket wall (202) such that the press-fit channel (206) extends proximally into the volume (V); The syringe barrel (200) has a hollow needle (205) press-fitted into the press-fit channel (206).

6. 6. The syringe barrel (200) of claim 5, wherein the needle hub (204) comprises a needle hub opening (207), the needle hub opening (207) having an inner taper radius tapering toward the central longitudinal axis (A) and a center of the needle hub opening (207).

7. 7. The syringe barrel (200) of claim 5 or 6, wherein the hollow needle (205) has a needle proximal end (208) having an outer taper radius tapering toward the longitudinal central axis (A) and the center of a vertical cross section of the hollow needle (205).

8. The syringe barrel (200) according to any one of claims 5 to 7, wherein the syringe barrel (200) is made from a polymer material, preferably a plastic selected from cycloolefin polymer (COP), cycloolefin copolymer (COC), or polypropylene (PP).

9. The syringe barrel (200) of any one of claims 5 to 8, wherein the proximal needle end (208) of the hollow needle (205) is substantially flush with the distal plunger socket wall (202).

10. A syringe (300) comprising a syringe plunger (100) according to any one of claims 1 to 4 and a syringe barrel (200) according to any one of claims 5 to 9.

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