Medical syringes and methods for reducing drug waste

Abstract

Medical syringes that dispense residual medication within the Luer tip reduce drug waste. The syringe plunger incorporates a ram rod with a jug at its distal end, which is inserted through the lumen of the Luer tip once the plunger has fully advanced into the syringe barrel. The central through-hole of the syringe stopper is slidably coupled to the ram rod in a liquid-sealed contact state. The central hole is initially oriented toward the ram rod on the jug. While the stopper is in its initial axial position, the medication is drawn into the syringe. Finally, the plunger is advanced with sufficient pressure to bring the stopper into contact with the Luer tip, moving the jug of the ram rod through the lumen of the Luer tip, thereby dispensing a single dose of medication by dispensing the medication held within the lumen.

Description

Technical Field

[0001] The present disclosure generally relates to medical syringes that maximize the use of a drug fluid within a syringe and reduce waste of the drug.

Background Art

[0002] Background After administration of a drug dosage, known medical syringes retain residual drug liquid in the syringe's luer tip, needle hub, and needle lumen. Most of the residual drug is held in the so-called "dead space" within the tip of the syringe and the needle hub. It is desirable to reduce waste of the drug by emptying the "dead space" during drug administration.

[0003] FIG. 1 shows a 1 ml dosing capacity medical syringe 10, which is a known prior art, having a syringe barrel 12 and a syringe luer tip 16 at the distal end 14 of the barrel. The luer tip defines a tip lumen 18 that is in fluid communication with a drug chamber defined within the syringe barrel 12. A movable syringe plunger 20 is coupled to a syringe stopper 22. The distal tip 24 of the syringe stopper 22 is in an orientation abutting the distal end 14 of the syringe barrel 12 and the lumen 18 of the luer tip 16. A needle hub 26 is coupled to the syringe's luer tip 16. The needle hub 26 holds a cup-shaped needle ferrule 28 in an orientation facing the tip lumen 18 and in fluid communication with the tip lumen 18. The needle ferrule 28 holds a hollow injection needle 30, and the needle lumen 32 is in fluid communication with the needle ferrule 28, the luer tip lumen 18, and the syringe cavity.

[0004] The distal tip 24 of the syringe stopper 22 is oriented to contact the distal end 14 and the lumen 18 of the Luer tip 16, so that the syringe 10 dispenses all of the drug pre-held in the syringe barrel 12. However, residual drug remains in three dead space zones distal to the distal end 24 of the syringe stopper, as shown in the crosshatch pattern in Figure 1: namely, the needle hub dead space 34, the needle lumen dead space 36, and the Luer tip lumen dead space 38. In a 1 ml capacity syringe 10, the needle lumen dead space has a relatively small volume of about 0.005 ml, the needle hub dead space 34 has a larger volume of about 0.030 ml, and the Luer tip dead space 38 has the largest volume of about 0.033 ml. The total dead space in a 1 ml dosing capacity syringe 12 is about 0.068 ml, or about 6.8% of the drug dosing volume. To completely distribute 1 ml of medication using syringe 12, 1.068 ml of medication must be drawn into the syringe to compensate for the 6.8 percent of medication that will be wasted. [Overview of the project] [Problems that the invention aims to solve]

[0005] The medical syringe described herein reduces drug waste by distributing residual drug remaining in the syringe barrel luer tip. [Means for solving the problem]

[0006] A ramrod, incorporated at the distal tip of the syringe plunger, advances through the lumen of the syringe barrel Luer tip, dispensing residual drug from the tip. In some embodiments, the syringe also dispensing residual drug remaining in the syringe needle hub, such as the needle ferrule. In clinical applications where multiple doses of a drug, such as a vaccine, are dispensed from the syringe, embodiments of the medical syringe of this disclosure dispense the more complete remaining dose, including a substantial amount of fluid, held in the Luer tip and needle hub.

[0007] One aspect of the present disclosure relates to a medical syringe, the medical syringe comprising a syringe barrel, an inner side wall, a proximal open end, a distal end, and a syringe cavity defined within the inner side wall and distal end of the syringe barrel. The syringe barrel has a barrel Luer tip at its distal end. The barrel Luer tip defines a tip outlet and a lumen through which fluid passes. The tip lumen has a cross-sectional area that establishes fluid communication between the syringe cavity and the tip outlet. The syringe has a plunger with a plunger shaft. The distal end of the plunger shaft is inserted into the syringe cavity and is movable within the syringe cavity. The ram rod has a proximal end firmly coupled to the distal end of the plunger shaft and an axial centerline of the ram rod that is coaxial with the axial centerline of the syringe. The ram rod is insertable at least to the tip outlet within the Luer tip lumen. The distal end of the ram rod defines a jug with a jug tip having a distal surface. The jug has a cross-sectional area measured perpendicular to the axial centerline of the lumen of the Luer tip, and this cross-sectional area is smaller than the corresponding cross-sectional area of ​​the tip lumen. The syringe stopper surrounds the outer circumferential surface of the ram rod and is slidably connected to the ram rod by a central hole that is in a biased, fluid-seal contact state with the outer circumferential surface of the ram rod. The syringe stopper has a distal axial end oriented opposite to the distal end of the syringe barrel, and together with the barrel, the syringe stopper defines the distal and proximal axial boundaries of the syringe cavity between them. The proximal end of the stopper is oriented opposite to the distal end of the plunger shaft, and the outer circumferential surface of the syringe stopper is in a fluid-seal contact state with the inner sidewall of the syringe barrel. The syringe stopper is oriented in its initial axial position on the ram rod, and its central hole is in biased contact with the jug during the initial insertion of the plunger into the syringe barrel and during the suction or distribution of fluid into or out of the syringe cavity. With the full advance of the syringe plunger within the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, and the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel, the jug of the ram rod is captured within the lumen of the Luer tip, and the tip of the jug is aligned at least axially with the outlet of the Luer tip.Therefore, any residual drug present in the lumen is distributed, providing a more complete drug dosage.

[0008] Another aspect of the present disclosure relates to a medical syringe having a syringe barrel having an axial centerline, an inner side wall surrounding the axial centerline, a proximal open end, a distal end, and a syringe cavity defined within the inner side wall and distal end of the syringe barrel. The syringe barrel has a barrel Luer tip at its distal end, the barrel Luer tip defining a tip outlet and a lumen through which it passes, coaxial with the axial centerline of the syringe. The tip lumen is in fluid communication with the syringe cavity and the tip outlet and has a cross-sectional area measured perpendicular to the axial centerline of the syringe barrel. The syringe includes a plunger having a plunger shaft coaxial with the axial centerline of the syringe barrel, the distal end of which is inserted into the syringe cavity and movable within the syringe cavity. The plunger shaft has at least one spacer ring projecting radially outward from the outer surface of the plunger shaft near the distal end of the plunger shaft to maintain coaxial alignment between the plunger and the inner side wall of the syringe barrel. The ram rod has a proximal end that is firmly coupled to the distal end of the plunger shaft and is coaxial with the axial centerline of the syringe. The ram rod is insertable into the lumen of the Luer tip at least to the tip outlet. The ram rod has a jug at its distal end, which has a jug tip. The jug tip has a distal surface that protrudes axially from the outlet of the lumen when the syringe plunger is fully advanced into the syringe barrel. The jug has a main lug and at least one secondary lug that protrudes radially outward with respect to the centerline of the syringe barrel, the main lug being measured perpendicular to the axial centerline of the syringe and having a cross-sectional area smaller than the corresponding cross-sectional area of ​​the tip lumen, and at least one secondary lug main lug having a cross-sectional area smaller than the cross-sectional area of ​​the main lug. The syringe stopper is slidably coupled to the ram rod, and its central hole surrounds the outer circumferential surface of the ram rod, and is in a fluid-seal contact state biased with the outer circumferential surface of the ram rod. The central hole of the syringe stopper defines a radially outward projecting recess for capturing the main lug and an additional recess for capturing the corresponding secondary lug. The syringe stopper has its distal axial end oriented opposite to the distal end of the syringe barrel, and together with the syringe barrel, the syringe stopper defines the distal and proximal axial boundaries of the syringe cavity between them.The proximal end of the stopper is oriented opposite the distal end of the plunger shaft, and the outer surface of the syringe stopper is in fluid-sealing contact with the inner sidewall of the syringe barrel. The syringe stopper is oriented on the ram rod in its initial axial position, and during the initial insertion of the plunger into the syringe barrel, and during the suction or distribution of fluid into or out of the syringe cavity, each recess of its central hole is in biased contact with the corresponding lug of the jug. With the full advance of the syringe plunger into the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, and the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel. In this final position, the jug of the ram rod is captured within the lumen of the Luer tip, the jug tip is axially aligned with the outlet of the Luer tip, and the distal surface of the jug tip protrudes axially from the lumen outlet.

[0009] A further aspect of this disclosure relates to a method for dispensing a drug remaining in the lumen of a Luer tip of a medical syringe. A syringe used to carry out embodiments of this method has a syringe barrel with a barrel Luer tip. The Luer tip has a tip outlet and a lumen through which it passes. A plunger is oriented within the syringe barrel communicating with the tip outlet. The plunger has a plunger shaft and a ram rod having a proximal end firmly coupled to the distal end of the plunger shaft. The jug at the distal end of the ram rod is insertable through the lumen of the Luer tip, at least to the tip outlet. A syringe stopper surrounds the ram rod and is slidably coupled to the ram rod by a central hole that is in a biased fluid-seal contact state. The syringe stopper is oriented on the ram rod in its initial axial position, with its central hole in a biased contact state on the jug. A needle hub is coupled to the Luer tip. The hub has a cup-shaped needle ferrule facing the outlet of the Luer tip and in fluid communication with the Luer tip, and a hollow needle coupled to the needle ferrule and in fluid communication with the needle ferrule. When performing an embodiment of this method, at least one dose is drawn into the syringe without moving the stopper from its initial position. If not done before the drug is drawn, the needle hub is coupled to the Luer tip. At least one dose of the drug is dispensed in the syringe by advancing the plunger with sufficient pressure, bringing the stopper into contact with the Luer tip, and moving the ramrod jug through the lumen of the Luer tip, so that the tip of the jug is aligned axially with the outlet, thereby dispensing the drug held in the lumen.

[0010] Exemplary embodiments of this disclosure are further described in the following detailed description in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1] This is an axial cross-sectional view of a conventional syringe with a needle hub. [Figure 1A] Figure 1 is a magnified view of the needle hub and Luer tip portion of a conventional syringe. [Figure 2] This is an axial cross-sectional view of an embodiment of the syringe of the present disclosure coupled to a needle hub, showing the syringe plunger, the ram rod of the syringe plunger, and the plunger stopper in a partially advanced position within the syringe barrel. [Figure 3] Figure 2 is an axial cross-sectional view of the syringe, where the plunger and ram rod are further advanced and the plunger stopper is in contact with the distal end of the syringe barrel and the lumen of its Luer tip. [Figure 3A] Figure 3 is a magnified view of the plunger stopper and ram rod of the syringe. [Figure 4] Figure 3 shows an axial cross-sectional view of the syringe with the plunger fully advanced and the plunger's ram rod fully advanced into the lumen of the luer tip. [Figure 4A] Figure 4 shows a magnified view of the syringe needle hub, luer tip, and the forward-extended ram rod portion. [Figure 5] Figure 2 is an exploded view of a syringe. [Figure 5A] Figure 5 is a magnified view of the ram rod and jug of the syringe. [Modes for carrying out the invention]

[0012] To facilitate understanding, the same reference numbers are used whenever possible to indicate identical elements common to the figures. The figures are not drawn at a fixed scale. Detailed description of the invention A medical syringe configured according to an aspect of this disclosure reduces wasted drug by using a ram rod at the distal end of the syringe plunger to move the drug that would otherwise be held in the dead space of its Luer tip. Once the plunger is fully advanced within the syringe barrel, the ram rod advances through the lumen of the syringe barrel Luer tip, distributing any remaining drug from the tip. In some embodiments, the syringe ram rod also moves the drug within a needle hub, such as a needle ferrule.

[0013] Aspects of the present disclosure also relate to a method for dispensing a drug remaining in the lumen of a medical syringe luer tip by advancing a ram rod, which is incorporated at the distal end of the syringe plunger, through a lumen within the syringe barrel luer tip. In some embodiments, the medical syringe used to dispense the residual drug has a syringe barrel having a barrel luer tip with a tip outlet and a lumen through which it passes. A plunger oriented within the syringe barrel communicates with the tip outlet. The plunger has a plunger shaft and a ram rod having a proximal end firmly coupled to the distal end of the plunger shaft. The jug at the distal end of the ram rod is insertable through the lumen of the luer tip at least to the tip outlet. A syringe stopper surrounds the ram rod and is slidably coupled to the ram rod by a central hole in a biased, fluid-seal contact state. Initially, the syringe stopper is oriented in an initial axial position on the ram rod, with its central hole in a biased contact state on the jug of the ram rod. The needle hub is coupled to the lure tip. The hub has a cup-shaped needle ferrule facing the outlet of the lure tip and in fluid communication with the lure tip, and a hollow needle coupled to the needle ferrule and in fluid communication with the needle ferrule.

[0014] In this embodiment of the residual drug distribution method, at least one dose of the drug is drawn into the syringe without moving the stopper from its initial position in contact with the ramrod jug.

[0015] If not already coupled before drug aspiration, the needle hub is coupled to the Luer tip. By advancing the plunger with sufficient pressure, the stopper is brought into contact with the Luer tip, and the ramrod jug is moved through the lumen of the Luer tip, dispensing at least one dose of the drug from the syringe, so that the jug tip aligns axially with the outlet, which dispenses any residual drug held in the lumen.

[0016] In the present disclosure, it is stipulated that the distal end of the instrument is the end closest to the patient, and the proximal end of the instrument is the end farthest from the patient and closest to the operator.

[0017] Regarding the terms used in the present disclosure, the following definitions are provided. As used herein, the use of "a", "an", and "the" includes both singular and plural forms.

[0018] As used herein, the term "catheter-related bloodstream infection" or "CRBSI" refers to any infection caused by the presence of a catheter or IV line.

[0019] As used herein, the term "Luer connector" refers to a connection collar, which is a standard method for attaching syringes, catheters, needles with hubs, IV tubes, etc. to each other. The Luer connector consists of male and female connecting tubes, which are slightly tapered so that they can be firmly held together with just a simple pressure / twist fit. The Luer connector may optionally include additional outer thread rims, which make them safer. The male end of the Luer connector is usually connected to a flush syringe and can be connected and joined to the female end disposed on a vascular access device (VAD). The Luer connector also has a distal end channel for removably attaching the Luer connector to the hub of the VAD and a proximal end channel for removably attaching the Luer connector to the barrel of the syringe.

[0020] As used herein, ISO80369-7:2016 defines the specifications of a standard Luer connector that includes a 6% taper between the distal end and the proximal end. The male standard Luer connector expands in diameter from the open distal end to the proximal end. The female standard Luer connector decreases in diameter from the open proximal end to the distal end. According to ISO80369-7:2016, the male standard Luer connector has an outer cross-sectional diameter in the range of 3.970 mm - 4.072 mm, measured 0.75 mm from the distal end of the tip. The length of the male standard Luer taper is between 7.500 mm and 10.500 mm. The outer cross-sectional diameter, measured 7.500 mm from the distal end of the tip, is between 4.376 mm and 4.476 mm. As used herein, the phrases "male standard Luer connector" and "female standard Luer connector" refer to connectors having the dimensions described in ISO80369-7, which are hereby incorporated by reference in their entirety.

[0021] As will be readily understood by those skilled in the relevant art, throughout this specification, descriptive terms such as "tip", "hub", "thread", "projection / insert", "tab", "slant", "wall", "upper", "side", "bottom", etc. are used for ease of understanding, but are not intended to limit the components that can be used in combination or individually to implement various aspects of the present disclosure.

[0022] As used herein, the "axial centerline" is a straight axis passing through the longest dimension of a medical syringe component, such as the internal cavity of a syringe barrel, a syringe plunger, or the lumen of a Luer tip of a syringe. In some embodiments of the present disclosure, the axial centerline is laterally offset from the center of gravity axis of the component. For example, a coaxially aligned Luer tip lumen, a ramrod, and a plunger of a syringe barrel are laterally offset from the center of gravity axis of the syringe barrel. Embodiments of the syringe of the present disclosure are shown with a cylindrical coaxial cross-section, but in other embodiments, the components may have other cross-sections, such as triangular, rectangular, and / or asymmetric cross-sections.

[0023] Before describing some exemplary embodiments of this disclosure, it should be understood that this disclosure is not limited to the configuration or process details described below. Other embodiments of this disclosure are possible and can be practiced or implemented in many ways.

[0024] The examples provided in this description are provided to aid in a comprehensive understanding of the exemplary embodiments of this disclosure. Those skilled in the art will understand that various modifications and alterations of the embodiments described herein can be made without departing from the scope and spirit of this disclosure. Furthermore, for clarity and brevity, descriptions of well-known functions and configurations are omitted.

[0025] Exemplary embodiments of the embodiments of the present disclosure are shown in Figures 2-5A. Referring to Figures 2 and 3, the syringe 40 includes a syringe barrel 42, a plunger 44 movable within the syringe barrel, a needle hub 46, a hollow needle 48 coupled to the needle hub, and a syringe stopper 50 coupled to the plunger 44. The syringe 40 and the syringe barrel 42 define axial centers coaxial with the respective centerlines of the plunger 44, needle hub 46, needle 48, and stopper 50. The syringe barrel 42 has a gripping tab 52 at its open proximal end. The distal end 54 of the syringe barrel 42 incorporates a barrel luer tip 56 having an internal luer tip lumen 58 passing through the barrel luer tip 56, which is coaxial with the axial centerline of the syringe 40. As shown in Figure 4A, the tip lumen 58 has a cylindrical profile and a diameter D1, the cross-sectional area of ​​which is measured perpendicular to the axial centerline of the syringe 40. The tip lumen 58 terminates at the distal tip outlet 59, as shown in Figures 3 and 5. The syringe barrel 42 has an inner side wall 60 that defines the barrel cavity 62, together with its distal end 54 and stopper 50. The tip lumen 58 establishes fluid communication between its tip outlet 59 and the syringe cavity 62.

[0026] Referring to Figures 2, 3A, and 5A, the plunger 44 has a plunger shaft 64 whose centerline is coaxial with the axial centerlines of the syringe 40 and the syringe barrel 42. The proximal end of the plunger shaft 64 defines a finger tab 66. At least one spacer ring 68 projects radially outward from the outer surface of the plunger shaft 64 to maintain coaxial alignment between the plunger shaft and the inner side wall 60 of the syringe barrel 42. At least one spacer ring 68 is oriented near the distal end 70 of the plunger shaft 64.

[0027] The ram rod 72 has a proximal end that is firmly coupled to the distal end 70 of the plunger shaft 64, is coaxial with the axial centerline of the plunger shaft, and is insertable into the lumen 58 of the lure tip 58, at least to the tip outlet 59. In some embodiments, the ram rod 72 is not insertable to the tip outlet 59. The distal end of the ram rod 72 defines a jug 74, which comprises a jug tip 76 and a distal surface 78 of the jug tip 76 that faces the lumen 58 of the lure tip 56. As shown in Figures 4 and 4A, the jug tip 76 has an axial length L1 such that when the syringe plunger 44 is fully advanced into the syringe barrel, the distal surface 78 of the jug tip 76 protrudes axially from the lumen outlet 59.

[0028] Referring to Figures 4A and 5A, the jug 74 has a main lug 80 and at least one secondary lug 82 projecting radially outward with respect to the axial centerline of the ram rod 72 or the axial centerline of the syringe barrel. In the exemplary, non-limiting embodiments shown in Figures 4A and 5A, the jug 74 has a main lug 80 and three secondary lugs 82 projecting radially outward with respect to the axial centerline of the ram rod 72 or the axial centerline of the syringe barrel. The Luer tip lumen 58, the ram rod 72, and the lugs 80, 82 have complementary cylindrical profiles and cross-sections that fit together, but in other embodiments, they may have other complementary cross-sections, such as square, triangular, elliptical, or asymmetrical cross-sections. The main lug 80 has a diameter D2 with a cross-sectional area measured perpendicular to the axial centerline of the ram rod 72, and the diameter D2 is smaller than the diameter D1 of the complementary corresponding cross-sectional area of ​​the tip lumen 58. The clearance gap between complementary diameters D1 and D2 is selected to allow fluid to be removed from the lumen without the ram rod 72 becoming immobile within the tip lumen 58. In Figure 5A, the secondary lug 82 has a smaller diameter D3 and cross-sectional area than the primary lug 80, preventing the ram rod 72 from becoming immobile within the tip lumen 58. The tip of the jug 76 has a diameter D4.

[0029] Referring to Figures 2, 3, and 3A, the syringe stopper 50 has a distal axial end 84 facing the distal end 54 of the barrel and oriented opposite to the distal end 54 of the barrel, a proximal end 86 facing the distal axial end 70 of the plunger shaft 64, and an outer peripheral surface 88 that is in fluid-seal contact with the inner side wall 60 of the syringe barrel 42. The inner side wall 60 of the barrel, together with the distal end 54 of the barrel and the distal axial end 84 of the syringe stopper 50, defines the barrel cavity 62, the volume of which changes depending on the axial position of the plunger stopper 50 and the plunger 44 to which the plunger stopper 50 is connected within the syringe barrel 42. The syringe stopper 50 is made of a flexible material (e.g., elastomer) and surrounds the outer surface of the ram rod, and is slidably coupled to the ram rod 72 by an internal or central hole 90 that is in a biased, fluid-seal contact state with the outer surface of the ram rod. The central hole 90 defines an internal recess 92 projecting radially outward for capturing the main lug 80 and the secondary lug 80.

[0030] As shown in Figure 2, the syringe stopper 50 is initially oriented in an axial position on the jug 74 of the ram rod 72, and during the initial insertion of the plunger 44 into the syringe barrel 42 and during the aspiration or distribution of fluid into or from the syringe cavity 62, each recess 92 of its central hole 90 is in biased contact with the corresponding lugs 80, 82 of the jug 74. In some embodiments, multiple doses of medication are dispensed using the same syringe 40 by replacing a new needle hub 46 and its attached needle 48. Next, referring to Figures 3 and 3A, the syringe stopper 50 remains engaged with the jug 74 during medication dispensing, while the plunger 44 is advancing, until the distal axial end 84 of the syringe stopper is in contact with the distal end 54 of the syringe barrel 42. In order to aspirate or dispense a fluid drug, the axial force applied to the plunger 44 within the syringe barrel 42 to retract or advance the coupled plunger stopper 50 of the plunger 44 is less than the shear axial force required to separate the mating contact between the stopper recess 92 and the lugs 80, 82 of the jug.

[0031] In Figure 3, after the syringe plunger 44 has fully advanced into the syringe barrel 42, if the distal axial end 84 of the syringe stopper 50 is in contact with the distal end 54 of the syringe barrel 42, residual drug remains in the lumen 58 of the syringe luer tip 56, the needle hub 46, and the needle 48, similar to the example of the conventional syringe 10 in Figure 1. The syringe 40 of this disclosure allows a healthcare professional to expel residual drug, reduce drug waste, and provide the patient with a complete drug dose by enabling the ram rod 72 to advance through the lumen 58 of the luer tip.

[0032] In Figures 4 and 4A, the syringe stopper 50 is moved along the ram rod 72 to its final axial position, and the distal axial end 84 of the syringe stopper 50 is in contact with the distal end 54 of the syringe barrel 42, applying an additional axial shear force to the plunger 44. This additional axial force advances the ram rod 72 into the lumen 58 of the Luer tip 56 by separating the lugs 80, 82 from the recess 92 of the stopper. Upon shear separation, this additional applied axial force advances the jug 74 through the exit 59 of the Luer tip 56. The distal surface 78 of the tip 76 of the jug protrudes into the cup-shaped needle ferrule 94 of the needle hub 46, and as a result, the distal surface 78 of the tip of the jug approaches the needle lumen 96 of the needle 48. The fully advanced ramrod 72 expels residual liquid drug from the lumen 58 of the syringe's luer tip 56 and partially expels drug from the residual dead space 98 of the needle ferrule 94. A relatively small amount of drug remains in the dead space 98 of the needle ferrule, and similarly, an even smaller amount remains in the dead space 100 of the needle lumen.

[0033] The following non-limiting examples illustrate the principle of reducing residual drug in a syringe according to one or more embodiments of the present disclosure. An embodiment of syringe 40 with a 1 ml dosing capacity significantly reduces drug dead space and drug waste compared to a known equivalent-capacity syringe 10 (about 0.068 ml of drug wasted). The ram rod 72 of syringe 40 distributes all the drug from the lure tip lumen 58, reducing the dead space 98 in the needle hub to about 0.01 ml, while the dead space 100 in the needle lumen remains at 0.005 ml. The total amount of drug wasted in the embodiment of syringe 40 is reduced to about 0.015 ml compared to the 0.068 ml wasted in a prior art embodiment of an equivalent-capacity syringe 10, representing a waste reduction of about 78 percent.

[0034] Embodiments of syringes disclosed herein are constructed from medical-grade materials known to those skilled in the art. In some embodiments, the barrel, plunger, and shaft described are made of polypropylene polymer. The seal is made of fiber-filled polytetrafluoroethylene (PTFE) polymer. The stopper is made of polyisoprene polymer. Embodiment Embodiment (a): A medical syringe comprising a syringe barrel, a plunger, a ram rod, and a syringe stopper. The syringe barrel has an inner side wall, a proximal open end, a distal end, a syringe cavity defined inside the inner side wall and distal end of the syringe barrel, and a barrel Luer tip at the distal end of the syringe barrel, the barrel Luer tip defining a tip outlet and a lumen through which the lumen defines an axial centerline of the lumen, the tip lumen establishing fluid communication between the syringe cavity and the tip outlet, and having a cross-sectional area measured perpendicular to the axial centerline of the lumen. The plunger includes a plunger shaft, the distal end of which is inserted into the syringe cavity and movable within the syringe cavity. The ram rod has a proximal end firmly coupled to the distal end of the plunger shaft and a ram rod axial centerline coaxial with the axial centerline of the lumen, the ram rod is insertable into the Luer tip lumen at least to the tip outlet. The distal end of the ram rod defines a jug with a jug tip having a distal surface, the jug having a cross-sectional area measured perpendicular to the axial centerline of the lumen, and this cross-sectional area is smaller than the corresponding cross-sectional area of ​​the tip lumen. The syringe stopper is slidably coupled to the ram rod and has a central hole that surrounds the outer circumferential surface of the ram rod and is in a fluid-seal contact state biased with the outer circumferential surface of the ram rod, the syringe stopper has a distal axial end oriented opposite to the distal end of the syringe barrel, defining the distal and proximal axial boundaries of the syringe cavity between them, the proximal end of the syringe stopper is oriented opposite to the distal end of the plunger shaft, and the outer circumferential surface of the syringe stopper is in a fluid-seal contact state with the inner sidewall of the syringe barrel. The syringe stopper is oriented in its initial axial position on the ram rod, and its central hole is in biased contact with the jug during the initial insertion of the plunger into the syringe barrel and during the suction or distribution of fluid into or out of the syringe cavity.

[0035] With the syringe plunger fully advanced into the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel, the jug of the ram rod is captured within the lumen of the Luer tip, and the tip of the jug is aligned at least axially with the exit of the Luer tip.

[0036] Embodiment (b): A syringe according to Embodiment (a), further comprising a jug tip defining at least one projection projecting radially outward with respect to the axial centerline of the ram rod.

[0037] Embodiment (c): A syringe according to Embodiment (b), further comprising a central hole in the syringe stopper defining at least one radially outward projecting recess for capturing at least one lug of the jug tip therein when the syringe stopper is in its initial axial position.

[0038] Embodiment (d): A syringe according to embodiment (b), further comprising a jug tip defining a main lug and at least one sub-lug having a cross-sectional area smaller than the cross-sectional area of ​​the main lug.

[0039] Embodiment (e): A syringe according to Embodiment (d), further comprising a central hole in the syringe stopper, wherein the central hole defines a radially outward projecting recess for capturing a primary lug and an additional recess for capturing a corresponding secondary lug when the syringe stopper is in its initial axial position.

[0040] Embodiment (f): A syringe according to embodiment (b), further comprising a jug tip that defines a distal surface projecting axially from the lumen outlet when the syringe plunger is fully advanced into the syringe barrel.

[0041] Embodiment (g): A syringe according to Embodiment (a), further comprising an outer surface of a plunger shaft defining at least one radially outward projecting spacer ring for maintaining coaxial alignment between the plunger and the inner side wall of the syringe barrel.

[0042] Embodiment (h): A syringe according to Embodiment (g), further comprising at least one spacer ring oriented in close proximity to the distal end of the plunger shaft.

[0043] Embodiment (i): A syringe according to Embodiment (a), wherein the forward force required on the plunger shaft to move the syringe stopper from its initial axial position to its final axial position is greater than the force required to move the syringe stopper while aspirating or distributing fluid into or out of the syringe cavity before the distal end of the syringe stopper contacts the distal end of the syringe barrel.

[0044] Embodiment (j): A syringe according to Embodiment (a), further comprising a needle hub coupled to a barrel luer tip, the needle hub having a cup-shaped needle ferrule oriented opposite to the outlet of the luer tip, and with the full forward movement of the syringe plunger within the syringe barrel, the jug tip of the ram rod is oriented within the needle ferrule.

[0045] Embodiment (k): A medical syringe comprising a syringe barrel, a plunger, a ram rod, and a syringe stopper. The syringe barrel has an axial centerline, an inner side wall surrounding the axial centerline, a proximal open end, a distal end, and a syringe cavity defined within the inner side wall and distal end of the syringe barrel, a barrel Luer tip provided at the distal end of the syringe barrel, the barrel Luer tip defining a tip outlet and a lumen passing through therein, which is coaxial with the axial centerline of the syringe, the tip lumen having fluid communication between the syringe cavity and the tip outlet, and having a cross-sectional area measured perpendicular to the axial centerline of the syringe barrel. The plunger has a plunger shaft coaxial with the axial centerline of the syringe barrel, the distal end of the plunger shaft is inserted into the syringe cavity and movable within the syringe cavity, and at least one spacer ring protrudes radially outward from the outer surface of the plunger shaft, close to the distal end of the shaft, in order to maintain coaxial alignment of the plunger and the inner side wall of the syringe barrel. The ram rod has a proximal end firmly coupled to the distal end of the plunger shaft, is coaxial with the axial centerline of the syringe, and is insertable into the lumen of the Luer tip at least to the tip exit, and a jug with a jug tip is provided at the distal end of the ram rod, the jug tip having a distal surface that protrudes axially from the lumen exit when the syringe plunger is fully advanced into the syringe barrel, the jug has a main lug and at least one secondary lug that protrude radially outward with respect to the centerline of the syringe barrel, the main lug having a cross-sectional area measured perpendicular to the axial centerline of the syringe, this cross-sectional area being smaller than the corresponding cross-sectional area of ​​the tip lumen, and at least one secondary lug having a cross-sectional area smaller than the cross-sectional area of ​​the main lug.The syringe stopper is slidably coupled to the ram rod and surrounds the outer circumferential surface of the ram rod, having a central bore that is in a biased, fluid-seal contact state with the ram rod. The central bore of the syringe stopper defines within it a radially outward projecting recess for capturing the primary lug, and within it an additional recess for capturing the corresponding secondary lug. The syringe stopper has a distal axial end oriented opposite to the distal end of the syringe barrel, defining the distal and proximal axial boundaries of the syringe cavity between them. The proximal end is oriented opposite to the distal end of the plunger shaft, and the outer circumferential surface of the syringe stopper is in fluid-seal contact state with the inner sidewall of the syringe barrel. The syringe stopper is oriented in its initial axial position on the ram rod, and each recess of its central bore is in biased contact with the corresponding lug of the jug during the initial insertion of the plunger into the syringe barrel and during the suction or distribution of fluid into or out of the syringe cavity. With the syringe plunger fully advanced into the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel, the ram rod's jug is captured within the lumen of the Luer tip, the jug tip is axially aligned with the Luer tip's outlet, and the distal surface of the jug tip protrudes axially from the lumen outlet.

[0046] Embodiment (l): A syringe according to Embodiment (k), wherein the forward force in the plunger shaft required to move the syringe stopper from its initial axial position to its final axial position is greater than the force required to move the syringe stopper while aspirating or dispensing liquid into or out of the syringe cavity before the distal end of the syringe stopper contacts the distal end of the syringe barrel.

[0047] Embodiment (m): A syringe according to Embodiment (k), further comprising a needle hub coupled to a barrel luer tip, the needle hub having a cup-shaped needle ferrule oriented opposite to the outlet of the luer tip, and with the full advance of the syringe plunger into the syringe barrel, the axial surface of the jug tip of the ram rod is oriented into the needle ferrule.

[0048] Embodiment (n): A method for dispensing a drug remaining in the lumen of a Luer tip of a medical syringe, the method comprising a medical syringe, the medical syringe comprising a syringe barrel having a barrel Luer tip having a tip outlet and a lumen through which it passes, and a plunger oriented within the syringe barrel and communicating with the tip outlet, the plunger comprising a plunger shaft and a ram rod having a proximal end firmly coupled to the distal end of the plunger shaft, a jug at the distal end of the ram rod that can be inserted through the Luer tip lumen at least to the tip outlet, and a syringe stopper slidably coupled to the ram rod by a central hole surrounding the ram rod and biased to the ram rod, the syringe stopper being oriented in its initial axial position on the ram rod and having its central hole biased to the jug A medical syringe is provided, comprising a syringe stopper in contact with the Luer tip, and a needle hub coupled to a Luer tip, the hub having a cup-shaped needle ferrule facing the outlet of the Luer tip and in fluid communication with the Luer tip, and a hollow needle coupled to the needle ferrule and in fluid communication with the needle ferrule; and a method for dispensing a drug, comprising: drawing at least one dose of a drug into the syringe without moving the stopper from its initial position; coupling the needle hub to the Luer tip if not done before drug aspiration; and dispensing at least one dose of a drug by advancing a plunger with sufficient pressure to bring the stopper into contact with the Luer tip, moving the ramrod jug through the lumen of the Luer tip, so that the tip of the jug is axially aligned with the outlet, thereby dispensing the drug held in the lumen.

[0049] Embodiment (o): A method for dispensing a drug according to Embodiment (n), further comprising advancing a plunger with sufficient pressure, bringing a stopper into contact with the lure tip, and moving the jug of the ram rod through the lumen of the lure tip so that the tip of the jug is inside the needle ferrule, thereby dispensing the drug held in the needle ferrule and lumen, thereby dispensing at least one dose of the drug.

[0050] Throughout this specification, any reference to “one embodiment,” “a particular embodiment,” “various embodiments,” “one or more embodiments,” or “embodiment” means that a particular feature, structure, material, or property described in relation to an embodiment is included in at least one embodiment of this disclosure. Therefore, any occurrence of phrases such as “in one or more embodiments,” “a particular embodiment,” “various embodiments,” “in one embodiment,” or “in an embodiment” in various places throughout this specification does not necessarily refer to the same embodiment of this disclosure. Furthermore, a particular feature, structure, material, or property may be combined in any suitable manner in one or more embodiments.

[0051] While the disclosure herein provides explanations with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the disclosure. It will be apparent to those skilled in the art that various modifications and changes can be made to this disclosure without departing from the spirit and scope of the invention. Accordingly, this disclosure is intended to include modifications and changes that fall within the scope of the appended claims and their equivalents.

Claims

1. A medical syringe, wherein the medical syringe is A syringe barrel comprising an inner side wall, a proximal open end, a distal end, a syringe cavity defined within the inner side wall and the distal end of the syringe barrel, and a barrel Luer tip at the distal end of the syringe barrel, wherein the barrel Luer tip defines a tip outlet and a lumen through which it passes, the lumen defines an axial center line of the lumen, the tip lumen establishes fluid communication between the syringe cavity and the tip outlet, and has a cross-sectional area measured perpendicular to the axial center line of the lumen, A syringe plunger having a plunger shaft, wherein the distal end of the plunger shaft is inserted into the syringe cavity and is movable within the syringe cavity, A ram rod having a proximal end firmly coupled to the distal end of the plunger shaft, and a ram rod axial center line coaxial with the lumen axial center line, wherein the ram rod is insertable into the lumen of the luer tip at least to the tip exit, The distal end of the ram rod defining a jug having a jug tip having a distal surface, wherein the jug has a cross-sectional area measured perpendicular to the axial centerline of the lumen, which is smaller than the corresponding cross-sectional area of ​​the tip lumen, A syringe stopper slidably coupled to the ram rod, wherein the syringe stopper surrounds the outer circumferential surface of the ram rod and has a central hole that is biased and in fluid-seal contact with the outer circumferential surface of the ram rod, the syringe stopper has a distal axial end oriented opposite to the distal end of the syringe barrel, defining the distal and proximal axial boundaries of the syringe cavity between them, the proximal end of the syringe stopper is oriented opposite to the distal end of the plunger shaft, and the outer circumferential surface of the syringe stopper is in fluid-seal contact with the inner side wall of the syringe barrel, During the initial insertion of the plunger into the syringe barrel, and during the suction or distribution of fluid into or out of the syringe cavity, the syringe stopper is initially oriented in the axial position on the ram rod, and its central hole is in biased contact with the jug. A medical syringe characterized in that, upon the full advance of the syringe plunger into the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel, the jug of the ram rod is captured within the lumen of the Luer tip, and the tip of the jug is aligned at least axially with the outlet of the Luer tip.

2. A syringe according to claim 1, further comprising a jug tip defining at least one lug projecting radially outward with respect to the axial center line of the ram rod.

3. A syringe according to claim 2, further comprising the central hole of the syringe stopper defining at least one radially outward projecting recess for capturing the at least one lug of the tip of the jug when the syringe stopper is in its initial axial position.

4. A syringe according to claim 2, further comprising the jug tip defining a main lug and at least one sub-lug having a cross-sectional area smaller than the cross-sectional area of ​​the main lug.

5. A syringe according to claim 4, further comprising the central hole of the syringe stopper, wherein, when the syringe stopper is in its initial axial position, the central hole of the syringe stopper defines a radially outward projecting recess for capturing the main lug and an additional recess for capturing the corresponding sub-lug.

6. A syringe according to claim 2, further comprising the jug tip which defines a distal surface that protrudes axially from the lumen outlet when the syringe plunger is fully advanced into the syringe barrel.

7. A syringe according to claim 1, further comprising the outer circumferential surface of the plunger shaft defining at least one radially outward projecting spacer ring to maintain coaxial alignment between the plunger and the inner side wall of the syringe barrel.

8. A syringe according to claim 7, further comprising the at least one spacer ring oriented near the distal end of the plunger shaft.

9. A syringe according to claim 1, characterized in that the forward force on the plunger shaft required to move the syringe stopper from its initial position to its final axial position is greater than the force required to move the syringe stopper during the aspiration or distribution of fluid into or out of the syringe cavity, before the distal end of the syringe stopper comes into contact with the distal end of the syringe barrel.

10. A syringe according to claim 1, further comprising a needle hub coupled to the barrel luer tip, wherein the needle hub has a cup-shaped needle ferrule oriented opposite to the outlet of the luer tip, and the jug tip of the ram rod is oriented within the needle ferrule upon the full advance of the syringe plunger into the syringe barrel.

11. A medical syringe, wherein the medical syringe is A syringe barrel having an axial centerline, an inner side wall surrounding the axial centerline, a proximal open end, a distal end, and a syringe cavity defined within the inner side wall and the distal end of the syringe barrel, wherein a barrel Luer tip is located at the distal end of the syringe barrel, the barrel Luer tip defines a tip outlet and a lumen passing through it, which is coaxial with the axial centerline of the syringe, the tip lumen is in fluid communication between the syringe cavity and the tip outlet, and the syringe barrel has a cross-sectional area measured perpendicular to the axial centerline of the syringe barrel, A syringe plunger having a plunger shaft coaxial with the axial centerline of the syringe barrel, wherein the distal end of the plunger shaft is inserted into the syringe cavity and movable within the syringe cavity, and at least one spacer ring protrudes radially outward from the outer circumferential surface of the plunger shaft near the distal end of the shaft to maintain coaxial alignment between the syringe plunger and the inner side wall of the syringe barrel, A ram rod, the ram rod being coaxial with the axial centerline of the syringe and insertable into the lumen of the luer tip at least to the tip outlet, the ram rod having a proximal end firmly coupled to the distal end of the plunger shaft, and a jug having a jug tip at the distal end of the ram rod, the jug tip having a distal surface that protrudes axially from the lumen outlet when the syringe plunger is fully advanced into the syringe barrel, the jug having a main lug that protrudes radially outward with respect to the axial centerline of the syringe barrel, and at least one sub-lug, the main lug having a cross-sectional area measured perpendicular to the axial centerline of the syringe that is smaller than the corresponding cross-sectional area of ​​the tip lumen, and the at least one sub-lug having a cross-sectional area smaller than the cross-sectional area of ​​the main lug, the ram rod, A syringe stopper slidably coupled to the ram rod, the syringe stopper having a central hole surrounding the outer circumferential surface of the ram rod and having a biased, fluid-seal contact with the outer circumferential surface of the ram rod, the central hole of the syringe stopper defining within it a radially outward projecting recess for capturing a main lug, and within it an additional recess for capturing a corresponding secondary lug, the syringe stopper having a distal axial end oriented opposite to the distal end of the syringe barrel, defining the distal and proximal axial boundary of the syringe cavity between them, the proximal end oriented opposite to the distal end of the plunger shaft, and the outer circumferential surface of the syringe stopper being in fluid-seal contact with the inner side wall of the syringe barrel, The syringe stopper is oriented in its initial axial position on the ram rod during the initial insertion of the plunger into the syringe barrel and during the suction or distribution of fluid into or out of the syringe cavity, with each recess of its central hole in biased contact with the corresponding lug of the jug. A medical syringe characterized in that, upon the full advance of the syringe plunger into the syringe barrel, the syringe stopper is moved along the ram rod to its final axial position, the distal axial end of the syringe stopper is in contact with the distal end of the syringe barrel, the jug of the ram rod is captured within the lumen of the luer tip, the tip of the jug is aligned axially with the outlet of the luer tip, and the distal surface of the jug tip protrudes axially from the lumen outlet.

12. A syringe according to claim 11, characterized in that the forward force on the plunger shaft required to move the syringe stopper from its initial axial position to its final axial position is greater than the force required to move the syringe stopper during the aspiration or distribution of fluid into or out of the syringe cavity, before the distal end of the plunger shaft comes into contact with the distal end of the syringe barrel.

13. A syringe according to claim 11, further comprising a needle hub coupled to the barrel luer tip, wherein the needle hub has a cup-shaped needle ferrule oriented opposite to the outlet of the luer tip, and upon full advance of the syringe plunger into the syringe barrel, the axial surface of the jug tip of the ram rod is oriented within the needle ferrule.

14. A method for dispensing a drug remaining in the lumen of the Luer tip of a medical syringe, wherein the method is: To provide a medical syringe, the medical syringe comprising: a syringe barrel having a barrel Luer tip with a tip outlet and a lumen through which it passes; a plunger oriented within the syringe barrel and communicating with the tip outlet, the plunger comprising: a plunger shaft; and a ram rod having a proximal end firmly coupled to the distal end of the plunger shaft; and a jug at the distal end of the ram rod, the jug being insertable through the lumen of the Luer tip to at least the tip outlet; and a slidably coupled jug to the ram rod by a central hole. To provide a medical syringe comprising: a syringe stopper, the central hole of which surrounds the ram rod and is in a biased, fluid-sealed contact state with the ram rod, the syringe stopper being initially oriented in an axial position on the ram rod and its central hole being in a biased contact state on the jug; and a needle hub coupled to a Luer tip, the needle hub having a cup-shaped needle ferrule facing the outlet of the Luer tip and in fluid communication with the Luer tip; and a hollow needle coupled to the needle ferrule and in fluid communication with the needle ferrule. Without moving the stopper from its initial position, at least one dose of the drug is drawn into the syringe. If this has not been done before aspirating the drug, the needle hub shall be connected to the luer tip, A method comprising: advancing the plunger with sufficient pressure, bringing the stopper into contact with the lure tip, moving the jug of the ram rod through the lumen of the lure tip, thereby aligning the tip of the jug axially with the outlet, and thereby distributing the drug held in the lumen, thereby distributing at least one dose of the drug.

15. A method for dispensing a drug according to claim 14, further comprising advancing the plunger with sufficient pressure to bring the stopper into contact with the lure tip, moving the jug of the ram rod through the lumen of the lure tip, so that the tip of the jug is in the needle ferrule, thereby dispensing at least one dose of the drug by dispensing the drug held in the needle ferrule and the lumen.

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