Syringe

Abstract

The utility model relates to a syringe. Dual chamber syringes facilitate selective drug mixing, dosing and administration through catheters or other vascular access devices (VADs) as well as pre-or post-administration irrigation of catheters with a single syringe instrument. A syringe barrel includes an outlet (such as a luer connector), variable volume concentrically oriented fluid chambers and secondary fluid chambers having nested respective plungers, plunger rods selectively translatable along a common axis inside the barrel, and plunger stops. A selectively resealable valve disposed within the barrel interior selectively isolates the secondary fluid chamber from the primary fluid chamber and / or the outlet of the syringe barrel. In some embodiments, the valve is a one-way valve. In some embodiments, the syringe is pre-packaged with an irrigation solution in the secondary fluid chamber, enabling sequential administration of the drug with the primary fluid chamber and immediate irrigation with the secondary fluid chamber.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application incorporates by reference in its entirety the following U.S. utility patent applications: entitled “DUAL CHAMBER SYRINGE WITH MANUALLY ACTUATED, CHAMBER ISOLATION VALVE” filed concurrently with this application and assigned serial number (UNKNOWN) and entitled “SYRINGE WITH TANDEM DUAL CHAMBERS” filed concurrently with this application and assigned serial number (UNKNOWN). Technical Field

[0003] The present disclosure generally relates to a dual chamber syringe assembly for administering two gases or fluids or for administering and flushing catheters and other vascular access devices (VADs) or for mixing and administering fluids and methods of flushing catheters. Background Art

[0004] VADs are commonly used therapeutic devices that include intravenous catheters. There are two general classifications of VADs, peripheral catheters and central venous catheters. VADs can become clogged if not properly maintained. To ensure that VADs are used correctly and do not become clogged, standards of practice have been developed. These standards include cleaning procedures, which are often referred to as flushing procedures or flushing the catheter.

[0005] VAD practice standards generally recommend flushing procedures after catheter placement, before infusion, and before and after medication, blood draws, fluids, and parenteral nutrition administration. The purpose of these flushing procedures is to confirm catheter patency, avoid medication incompatibilities, ensure complete dosing, prevent thrombosis, and minimize the risk of bloodstream infection. Flushing procedures require several types and amounts of flushing solutions. Commonly used flushing solutions are normal saline and / or heparin lock solutions. The type and amount of flushing solution varies depending on the specific catheter type. A flushing solution volume between 5 and 10 mL is most common, but can vary from 1 mL to 20 mL.

[0006] For flushing procedures, an intravenous line refers to a system that includes a VAD, a clamped tubing set, and may have a port or valve at the end. The most common type of port is covered by a penetrable septum or a pre-slit septum, known in the art and sometimes referred to as a "PRN" (from the Latin pro re nata, meaning "as needed"). The septum is preferably made of rubber or another elastic material that allows a sharp needle cannula to be inserted for infusion or withdrawal of fluid from the catheter. The septum seals itself after the needle cannula is removed. Ports with pre-slit septa are used with blunt cannulas or frusto-conical tips of syringe barrels. The syringe tip or blunt cannula (usually attached to a syringe) is gently pushed through the pre-slit septum to establish fluid communication.

[0007] Intravenous valves, as another terminal intravenous access device that does not require a needle with a sharp tip, are activated by the truncated cone-shaped end of the syringe barrel to allow fluid communication between the interior of the syringe and the catheter. These valves may contain a structure that delivers fluid from a storage chamber in the valve to the catheter, and are known in the art as positive displacement valves.

[0008] Removing debris or residue is called "cleaning" or "flushing" and prevents the accumulation of blood sediment, blood residue, and intravenous medications within catheters or other VAD devices. This accumulation can lead to partial or complete blockage of the fluid pathways in the catheter system and may require expensive, potentially dangerous procedures to clean the affected catheter or replace the catheter entirely. Often, this blockage results in interruptions in therapy, which can impact patient care. The accumulation of debris within the catheter can also increase the risk of infection by providing a breeding ground for microorganisms.

[0009] As will be appreciated by those skilled in the art, the flushing technique involves injecting a flushing solution (e.g., saline) into the VAD to clear debris and obstructions. The injection is typically performed by advancing a plunger rod into a prefilled syringe barrel, thereby expelling the flushing solution into the VAD. When this technique is used with a catheter, turbulence is introduced within the catheter to dislodge any debris or residue attached to the catheter. The flushing technique requires applying a substantially constant pressure or force to the plunger rod in the distal direction. Traditional or smooth flushing techniques may also include applying a substantially linearly increasing or decreasing pressure or force to the plunger rod in the distal direction.

[0010] After flushing, the physician can then administer a dose of a medical fluid, which is contained in a vial that needs to be drawn from it, or in a separate pre-filled syringe. However, connecting multiple devices to a VAD introduces the connector to a non-sterile external environment, introducing the possibility of transmitting a catheter-related bloodstream infection (CRBSI), which can be costly and potentially fatal. To reduce cases of CRBSI and ensure proper use and maintenance of VADs, standards of practice have been developed, including disinfection and cleaning procedures.

[0011] In clinical practice, intravenous flushing is performed after intravenous administration, usually using two separate syringes.

[0012] There is a need for a syringe assembly having a means to both flush a VAD and administer a dose of a medical fluid, thereby reducing the risk of CRBSI. There is also a need for a single syringe for intravenous flushing following intravenous administration to increase clinician efficiency and reduce costs associated with maintaining syringe inventory and medical waste disposal. Utility Model Content

[0013] The dual chamber syringe is helpful for selective drug mixing, dosing and application through a catheter or other vascular access device (VAD) and flushing before or after the application of the catheter with a single syringe device. The syringe barrel includes an outlet (such as a Luer connector), a main fluid chamber and a secondary fluid chamber of a concentric orientation, and the main fluid chamber and the secondary fluid chamber of the concentric orientation have nested corresponding plungers, a plunger rod and a plunger stopper that can be selectively translated along a common axis inside the barrel. The selective resealable valve disposed inside the barrel selectively isolates the secondary fluid chamber from the outlet of the main fluid chamber and the syringe barrel. In certain embodiments, the valve is a one-way valve, such as a duckbill valve, which prevents backflow into the secondary chamber. The isolated secondary chamber structure is advantageously convenient for using prepackaged medicine or flushing solutions in the chamber. The syringe of the type disclosed herein is used in medical procedures that require flushing and administration of medicines by a catheter or other VAD to reduce the need to perform multiple infusions and extract multiple single-function syringes. Use of the disclosed syringes advantageously reduces the risk of infection to patients, reduces costs associated with syringe inventory and subsequent waste disposal, and reduces the time required for clinicians to complete related medical procedures.

[0014] One aspect of the present disclosure relates to a syringe, comprising a substantially cylindrical barrel, wherein the barrel defines an inner sidewall, the barrel having an open proximal end and a distal end. The distal end of the barrel comprises a connector, such as a Luer connector, the connector defining an outlet chamber therethrough, the outlet chamber being in fluid communication with the interior of the barrel. The barrel interior is defined by the open proximal end, the distal end, and the inner sidewall of the barrel. The syringe also comprises a concentrically nested main plunger and a secondary plunger, the main plunger and the secondary plunger being disposed within the barrel interior, respectively having a main plunger rod and a secondary plunger rod that can selectively translate along a common axis within the barrel interior. A main stopper is coupled to the distal end of the main plunger. It has a proximal surface facing the proximal end of the barrel, a distal surface facing the distal end of the barrel, and also defines a through hole between its proximal and distal surfaces, the through hole being in fluid communication with the outlet chamber. A secondary stopper is coupled to the distal end of the secondary plunger; having a distal surface facing the distal end of the barrel. A resealable valve is disposed within the interior of the barrel, axially offset from the distal surface of the secondary stopper along the common axis toward the distal end of the barrel. The resealable valve has an inlet in fluid communication with the distal surface of the secondary stopper and an outlet in fluid communication with the through hole of the main stopper and the outlet chamber. The syringe has an annular variable volume main fluid chamber, which is defined within the barrel interior between the distal surface of the main stopper and the distal end of the barrel. The volume of the main fluid chamber can be selectively changed by translation of the main plunger rod. The syringe also has a variable volume secondary fluid chamber, which is nested within the main fluid chamber and within the barrel interior, defined between the distal surface of the secondary stopper and the valve inlet. The secondary fluid chamber is in fluid communication with the valve inlet. The volume of the secondary fluid chamber can be selectively changed by translation of the secondary plunger rod. When the valve is closed, the secondary fluid chamber is isolated from the outlet chamber, so that translation of the primary plunger rod draws fluid into or dispenses fluid out of the primary chamber only via the outlet chamber. When the valve is open, the secondary fluid chamber is in fluid communication with the outlet chamber, so that translation of the secondary plunger rod draws fluid into or dispenses fluid out of the secondary chamber via the outlet chamber.

[0015] In some embodiments of the syringe disclosed herein, its secondary chamber is pre-filled with a flushing solution. Desirably, a clinician can administer medication into a patient's VAD with the primary chamber and immediately flush the VAD with the secondary chamber without removing the syringe from the VAD. In other embodiments of the syringe disclosed herein, a clinician can administer medication through the VAD and immediately flush the VAD with a single, continuous advancement of the two dual plungers.

[0016] Another aspect of the present disclosure relates to a syringe, comprising a substantially cylindrical barrel, the barrel defining an inner sidewall, wherein the barrel has an open proximal end and a distal end. The distal end of the barrel comprises a connector, the connector defining an outlet chamber passing therethrough, the outlet chamber being in fluid communication with the interior of the barrel. The barrel interior is defined by the open proximal end of the barrel, the distal end, and the inner sidewall. The syringe comprises an inner barrel having a distal top end adjacent to the distal top end of the barrel and being nested in the barrel in a radially spaced relationship. Concentrically nested main plungers and secondary plungers are disposed within the barrel interior, respectively having a main plunger rod and a secondary plunger rod that can selectively translate along a common axis within the barrel interior. The main plunger surrounds the inner barrel, and the secondary plunger is nested within the inner barrel. A main stopper is coupled to the distal end of the main plunger. The main stopper has an annular cross section, a proximal surface facing the proximal end of the barrel, and a distal surface facing the distal end of the barrel. The main stopper defines a through hole between its proximal and distal surfaces for receiving the inner barrel therein. The main stopper is in fluid communication with the outlet chamber. The secondary stopper is coupled to the distal end of the secondary plunger. The secondary stopper has a distal surface facing the distal end of the barrel. The syringe also includes a resealable valve, which is disposed inside the barrel interior; it is axially offset along the common axis away from the distal surface of the secondary stopper toward the distal end of the barrel. The resealable valve has a valve inlet coupled to the distal top end of the inner barrel. The valve inlet is in fluid communication with the distal surface of the secondary stopper. The resealable valve also has an outlet in fluid communication with the through hole of the main stopper and the outlet chamber. The resealable valve selectively isolates the secondary chamber from the outlet chamber and the main chamber. An annular primary fluid chamber is defined within the distal surface of the primary stopper, the distal end of the barrel, the inner sidewall of the barrel, and the outer sidewall of the inner barrel. The volume of the primary fluid chamber can be selectively changed by translation of the primary plunger rod. A secondary fluid chamber is defined within the distal surface of the secondary stopper, the distal top of the inner barrel, and the inner sidewall of the inner barrel, the distal top of the inner barrel including the valve inlet. The secondary fluid chamber is in fluid communication with the valve inlet. The volume of the secondary fluid chamber can be selectively changed by translation of the secondary plunger rod. When the syringe is used, when the valve is closed, the secondary fluid chamber is isolated from the outlet chamber, so that translation of the primary plunger rod only draws fluid into the primary chamber or dispenses fluid out of the primary chamber via the outlet chamber. When the valve is open, the secondary fluid chamber is in fluid communication with the outlet chamber such that translation of the secondary plunger rod dispenses fluid out of the secondary chamber via the outlet chamber.

[0017] In some embodiments, the resealable valve comprises a one-way valve, such as a duckbill-type valve. In some embodiments, the main plunger comprises a tubular profile. In some embodiments, the inner surface of the distal end of the barrel defines a seat surface for abutting engagement with a distal end surface of the main stop when the main stop is fully advanced within the barrel, thereby isolating the main chamber from the outlet chamber and the outlet of the valve.

[0018] In some embodiments, the inner surface of the distal end of the secondary chamber defines a seat surface, and the seat surface is used to abut and engage with the distal end surface of the secondary stop when the secondary stop is fully advanced in the barrel, thereby isolating the secondary chamber from the outlet cavity and the outlet of the valve.

[0019] In some embodiments, the secondary plunger rod is selectively coupled to the secondary plunger when dispensing fluid from the secondary chamber. In some embodiments, the secondary plunger rod is selectively coupled to the secondary plunger using mating male and female threads.

[0020] The aspects of the present disclosure and the respective features of the exemplary embodiments described herein may be applied jointly or individually in any combination or sub-combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Exemplary embodiments of the present disclosure are further described in the following detailed description in conjunction with the accompanying drawings, in which:

[0022] Figure 1 is a cross-sectional view of an embodiment of a dual chamber syringe having a primary fluid chamber and a secondary fluid chamber oriented concentrically, wherein each chamber contains a fluid;

[0023] Figure 2 is a cross-sectional view of a one-way duckbill valve in a sealed or closed state;

[0024] Figure 3 is in open state Figure 2 A cross-sectional view of a one-way duckbill valve;

[0025] Figure 4-7 is used Figure 1 Illustrative sequential steps of a syringe of FIG. 1, respectively showing aspiration and dispensing / infusion of a fluid (e.g., a drug) in a primary chamber into an intravenous fluid conduit or port, and then flushing the conduit with fluid in a secondary chamber;

[0026] Figure 8 is a cross-sectional view of another embodiment of a dual chamber syringe including an externally actuated isolation valve, wherein each chamber contains a fluid;

[0027] Fig. 9 yes Figure 8 Exploded view of the syringe;

[0028] Fig.10 and Fig.11 yes Figure 8 Detailed cross-sectional view of a syringe of , showing the needle valve in closed and open positions, respectively;

[0029] Fig.12 yes Figure 8 A perspective view of a syringe showing the Fig.10 and Fig.11 The closed and open positions selectively engage a cam groove of a needle valve;

[0030] Fig.13 is a cross-sectional view of another embodiment of a dual chamber syringe in which a secondary or proximal chamber is included within a primary plunger thereof and is pre-filled with a fluid;

[0031] Fig.14 yes Fig.13 a cross-sectional view of a syringe wherein another fluid has been drawn into its main chamber or distal chamber;

[0032] Fig.15 yes Fig.13 A cross-sectional view of a syringe wherein fluid in a secondary or proximal chamber is being dispensed;

[0033] Fig.16 yes Fig.13 A cross-sectional view of the syringe after all of the fluid in the secondary chamber or the proximal chamber has been dispensed; and

[0034] Fig.17 is a cross-sectional view of another embodiment of a dual chamber syringe in which a secondary or proximal chamber is included within its main plunger.

[0035] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale. DETAILED DESCRIPTION

[0036] Aspects of the dual chamber syringe embodiments disclosed herein facilitate selective drug mixing, dosing and administration through a catheter or other vascular access device (VAD) and flushing before or after administration of a catheter with a single syringe apparatus. Typically, in each disclosed embodiment, the syringe barrel includes an outlet, such as a Luer connector, which is selectively fluidly connected to the main variable volume fluid chamber and the secondary variable volume fluid chamber. In some embodiments, the chamber pair has a series, in-line orientation in the syringe barrel, and in other embodiments, the chamber pair is nested in a roughly concentric orientation. In any type of chamber orientation, for each chamber, the syringe includes a corresponding plunger nested, a plunger rod that can be selectively translated along a common axis inside the barrel, and a plunger stopper. Therefore, a separate drug or other fluid (e.g., flushing solution) is selectively and independently distributed by a clinician. A selectively resealable valve disposed inside the barrel selectively isolates the secondary fluid chamber from the outlet of the main fluid chamber and the syringe barrel. In other embodiments, the valve is a one-way valve, such as a duckbill valve, which prevents backflow into the secondary chamber.

[0037] The isolated secondary chamber configuration advantageously facilitates the use of prepackaged medications or flushing solutions in the chamber, whereby the clinician can aspirate and dispense medications with the empty primary chamber, and immediately thereafter deliver the prepackaged flushing solution from the secondary chamber. In other embodiments, the syringe disclosed herein is used as a medication mixing syringe, prepackaged with a powdered medication in the primary chamber, and prepackaged with a diluent solution in the secondary chamber. In some embodiments, a single forward stroke on the nested primary and secondary plungers of the syringe automatically delivers or infuses into the VAD sequentially. The medication contained in the primary chamber, followed by the flushing solution.

[0038] In this disclosure, a convention is followed where the distal end of a device is the end closest to the patient, e.g., for delivery of one or more drugs to the patient, and the proximal end of the device is the end distal to the patient and closest to a clinician or other medical practitioner. With respect to terms used in this disclosure, the following definitions are provided.

[0039] As used herein, the use of "a", "an" and "the" includes both the singular and the plural.

[0040] As used herein, the term "Luer connector" refers to a connecting collar that is a standard way to interconnect syringes, catheters, seated needles, intravenous tubing, etc. A Luer connector consists of male and female interlocking tubes that are slightly tapered to better secure them together even with just a simple press / twist fit. The Luer connector can optionally include an additional threaded outer rim to make it more secure. The male end of the Luer connector is associated with a flush syringe and can interlock and connect with the female end located on a vascular access device (VAD). The Luer connector also has a distal channel that releasably connects the Luer connector to the seat of the VAD and a proximal channel that releasably connects the Luer connector to the barrel of a syringe.

[0041] As used herein, ISO80369-7:2016 defines the specifications of a standard Luer connector, including a 6% taper between the distal end and the proximal end. The male standard Luer connector increases from the open distal end to the proximal end. The female standard Luer connector decreases from the open proximal end to the distal end. According to ISO80369-7:2016, the outer cross-sectional diameter of the male standard Luer connector measured at 0.75 mm from the distal end of the end is between 3.970 mm and 4.072 mm. The length of the male standard Luer taper is between 7.500 mm and 10.500 mm. The outer cross-sectional diameter measured at 7.500 mm from the distal end of the end is between 4.376 mm and 4.476 mm. The phrases "male standard Luer connector" and "female standard Luer connector" used herein shall refer to connectors with the sizes described in ISO80369-7, and the entire contents of ISO80369-7 are incorporated herein by reference.

[0042] As will be readily understood by those skilled in the relevant art, although descriptive terms such as "end", "seat", "thread", "protrusion / insertion portion", "tab", "ramp", "wall", "top", "side", "bottom", etc. are used in this specification to facilitate understanding, this does not mean that there is any limitation on any components that can be combined or used alone that require a specific spatial orientation to realize the various aspects of the embodiments of the present disclosure.

[0043] Before describing several exemplary embodiments of the present disclosure, it should be understood that the present disclosure is not limited to the details of the structures or process steps described below. The present disclosure is capable of other embodiments and can be practiced or implemented in many ways.

[0044] The matters cited in this description are intended to help fully understand the exemplary embodiments of the present disclosure. Therefore, those of ordinary skill in the art will recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and structures have been omitted for clarity and brevity.

[0045] In an exemplary embodiment of the present disclosure, the barrel of the syringe includes a distal end having a needleless connection. In one or more embodiments, the needleless connection includes all combinations of at least one thread and other features to enable it to be connected to a corresponding thread or threads of a corresponding connector.

[0046] According to a further exemplary embodiment of the present disclosure, the configuration of the structural elements constituting the needleless connector includes a collar protruding from a distal end of the barrel, the collar including at least one thread to connect to a corresponding thread or threads of a corresponding connector.

[0047] According to further exemplary embodiments of the embodiments of the present disclosure, the collar or needleless connector may be bent or elastically deformed to provide a better interference fit with a corresponding connector.

[0048] According to further exemplary embodiments of embodiments of the present disclosure, the needleless connector may include: internal threads, the size and thread form of which are configured to engage with a standard ISO594-2 type male fitting; and / or external threads, the size and thread form of which are configured to engage with a standard ISO594-2 type female fitting. An example of an ISO594-2 type fitting is a Q-type fitting.

[0049] In one or more embodiments, the female connector can be selected from the group consisting essentially of a needle connector (for direct injection into a patient or insertion into a vial to draw a dose of medication therefrom), a needleless connector, a catheter Luer connector, a stopcock, and a hemodialysis connector. In one or more embodiments, the needleless connector is selected from Q-type connector, MaxPlus, MaxPlus Clear, MaxZero, UltraSite, Caresite, InVision-Plus, Safeline, OneLink, V-Link, ClearLink, NeutraClear, Clave, MicroClave, MicroClave Clear, Neutron, NanoClave, Kendall, Nexus, InVision, Vadsite, Bionector, and the like.

[0050] In one or more embodiments, the male connector may be a venous tubing end or a stopcock.

[0051] Now refer to the accompanying drawings, Figure 1-7, wherein a syringe 20 has a concentrically oriented dual chamber. The syringe 20 includes a substantially cylindrical outer barrel 22 defining an inner sidewall 24, an open proximal end 26, a plunger stop 27 radially projecting inwardly, and a distal end 28. The distal end 28 of the outer barrel 22 includes a Luer connector 30 defining an outlet cavity 32 for attachment to and fluid communication with various associated VAD connectors (schematically shown as connector 34). The interior 36 of the outer barrel 22 is generally defined and delimited by its inner sidewall 24, the open proximal end 26, the open proximal end 26, and its distal end 28. The syringe 20 has an inner barrel 38 nested within the outer barrel 22 in a radially spaced relationship. The inner barrel 38 has an open proximal end 39 and a distal tip 40 proximal to the distal end 28 of the outer barrel 22. The inner barrel 38 has corresponding inner sidewalls 42 and outer sidewalls 44. The interior 45 of the inner barrel 38 is generally defined and bounded by its inner sidewall 42 , its open proximal end 39 , and its distal top end 40 .

[0052] The syringe 20 has a nested primary plunger 46 and secondary plunger 48, each having a primary plunger rod 50 and a secondary plunger rod 52 that are selectively translatable along a common axis within the interior 36 of the outer barrel 22. Figure 1 As shown, the main plunger rod 50 has a tubular construction that is integral with the main plunger 46. The main plunger 46 is nested within the outer barrel 22 and around the inner barrel 38. The secondary plunger 48 is in turn nested within the inner barrel 38 and the main plunger 46. The secondary plunger rod 52 is selectively attached to the inner plunger head 54 of the secondary plunger 48 by a screw 56, wherein the male threads of the screw engage the mating female threads formed in the secondary plunger rod.

[0053] An annular main stopper 58 is connected to the distal end of the main plunger 46. The main stopper 58 has a proximal surface 60 facing the proximal end 26 of the outer barrel 22, and a distal surface 62 facing the distal end 28 of the outer barrel. The main stopper 58 is in fluid communication with the outlet chamber 32. The inner diameter 64 of the annular main stopper 58 is in fluid-tight contact with the outer side wall 44 of the inner barrel 38, and defines a through hole between its proximal surface 60 and distal surface 62. A variable volume annular main chamber 66 (also referred to as a main cavity) is in fluid communication with the outlet chamber 32 via a passage 67. However, when the main stopper 58 is fully advanced into the outer barrel 22, its distal surface 62 abuts a mating seat surface on the barrel distal end 28, thereby isolating the main chamber 66 from the passage 67 and the outlet chamber 32. The annular shape of the main chamber 66 is defined within the boundaries of the distal end surface 62 of the main stopper 58, the distal end 28 of the outer barrel 22, the inner sidewall 24 of the outer barrel 22, and the outer sidewall 44 of the inner barrel 38. Translation of the main plunger rod 50 changes the volume of the main chamber 66. Withdrawal or retraction of the main plunger rod 50 draws fluid from the outlet chamber 32 into the main chamber 66. Retraction of the main plunger rod 50 is limited by contact with the internal stopper 27 formed in the outer barrel 22. Conversely, insertion or advancement of the main plunger rod 50 moves fluid through the outlet chamber 32 and out of the main chamber 66. Therefore, a clinician can selectively draw fluid, such as a drug or flushing solution, into or out of the main chamber 66 of the syringe 20.

[0054] The secondary stopper 68 is coupled to the inner plunger head 54 at the distal end of the secondary plunger 48. The end cap 53 is coupled to the proximal open side of the inner barrel 38 to prevent the inner plunger head 54 and the secondary stopper 68 from being accidentally removed or separated from the inner barrel. The secondary stopper has a distal surface 70 facing the distal tip 40 of the inner barrel 38 and the distal end 28 of the outer barrel 22, and an outer circumferential surface 72 in fluid-tight contact with the inner sidewall 42 of the inner barrel 38. A variable volume secondary chamber 74 (also referred to as a secondary cavity) is defined within the boundaries of the distal surface 70 of the secondary stopper 68 and the distal tip 40 and the inner sidewall 42 of the inner barrel 38. The translation of the secondary plunger rod 52 changes the volume of the secondary chamber 74. The translation of the secondary plunger rod 52 changes the volume of the secondary chamber 74. Thus, the clinician can selectively expel fluid (e.g., medication or flushing solution) from the secondary chamber 74 by advancing the secondary plunger rod 52 into the syringe 20. In some embodiments, when the syringe 20 is prepackaged with fluid in the secondary chamber 74, the secondary plunger rod 52 is intentionally separated from the secondary plunger 48 to prevent inadvertent dosing. The clinician attaches the secondary plunger rod 52 before administering the prepackaged dose to the patient.

[0055] Figure 1-7The syringe 20 embodiment includes a one-way valve 76 coupled to the distal tip 40 of the inner barrel 38 for selectively isolating the secondary chamber 74 from the outlet chamber 32 of the Luer connector 30. When the syringe 20 is in use, the clinician can expel fluid from the secondary chamber 74 to the outlet chamber 32 by advancing the secondary plunger rod 52 into the inner barrel 38, but cannot draw fluid into the secondary chamber. Therefore, the one-way valve 76 acts as a check valve. Figure 2 and Figure 3 The physical structure and operation of the one-way valve 76 are schematically shown in FIG. The one-way valve 76 is a duckbill-type valve composed of a monolithic elastomer (e.g., medical grade silicone) with a conical or frustoconical profile. The inlet 78 of the duckbill valve 76 is coupled to the distal tip 40 of the inner barrel 38, and the outlet 80 thereof is oriented to face the Luer connector 30. Figure 3 As shown, when the pressure P1 in the Luer connector 30 is greater than or equal to the pressure P2 in the secondary chamber 74, the outlet 80 is in a sealed relaxed state. Figure 3 When the pressure P2 is greater than the pressure P1 , such as when the secondary plunger 48 is advanced into the syringe 20 , the elastic body in the valve 76 stretches and deforms radially outward, discharging the fluid from the secondary chamber 74 .

[0056] Figure 4-7 The functional operation of the syringe 20 is depicted by first withdrawing the main plunger 46 to draw the drug from the vial 84 into its main chamber 66 via the Luer connection 30 ( Figure 4 ). Drug is infused from the main chamber 66 into the previously flushed VAD 34 by advancing the main plunger 46, thereby emptying the main chamber ( Figure 5 If not previously secured to the syringe 20, the secondary plunger rod 52 is secured to its corresponding inner plunger head 54 ( Figure 6 ). The VAD 34 is flushed with a flushing solution (eg, saline or heparin) prepackaged in the secondary chamber 74 by advancing the secondary plunger rod 52. The syringe 20 is then withdrawn from the VAD 34 once the flushing procedure is complete.

[0057] exist Figure 8-12Another aspect of the present disclosure is shown, wherein a dual chamber syringe 90 has a main chamber 92 and a secondary chamber 94 of variable volume in series, axially aligned and oriented, the secondary chamber 94 having a manually actuated selective isolation valve 96 that facilitates the drawing of fluid into or the expulsion of fluid from its secondary chamber. In one or more embodiments, the main chamber 92 is filled with a desired amount of saline flush fluid. In one or more embodiments, the main chamber 92 is filled with a desired drug. In one or more embodiments, the secondary chamber 94 is filled with a desired amount of saline flush fluid. In one or more embodiments, the secondary chamber 94 is filled with a desired drug. In one or more embodiments, both the main chamber 92 and the secondary chamber 94 are filled with a desired drug. In one or more embodiments, both the main chamber 92 and the secondary chamber 94 are filled with a desired amount of saline flush fluid. The main chamber 92 and / or the secondary chamber 94 are pre-filled with fluid during or after the syringe 90 is assembled using a sterile filling method. In addition, the barrel 98 of the syringe 90 may include measurement markings 99 to indicate the amount of fluid contained therein.

[0058] The syringe 90 includes a substantially cylindrical barrel 98 defining an inner sidewall 100. The barrel 98 has an open proximal end 102 and a distal end 104. The distal end 104 of the barrel 98 includes a luer connector 106 defining an outlet chamber 108 therethrough. The outlet chamber 108 is in fluid communication with an interior 110 of the barrel 98, wherein the interior is defined by the open proximal end 102, the distal end 104, and the inner sidewall 100.

[0059] The syringe 90 includes a nested main plunger 112 and a secondary plunger 114, which are disposed within the barrel interior 110 and have integral tubular main and secondary plunger rods, respectively, that are selectively translatable along a common axis within the barrel interior. A threaded plunger nut 115 cooperates with an external thread formed on the distal end of the main plunger 112, which also captures the secondary plunger 114 and holds the two plungers in a nested orientation.

[0060] A primary stopper 116 is coupled to the distal end of the primary plunger 112. The primary stopper 116 has a proximal surface 118 facing the open proximal end 102 of the barrel 98 and a distal surface 120 facing the distal end 104 of the barrel. The primary stopper 116 defines a through hole 122 between its proximal surface 118 and distal surface 120, and the through hole 122 is in fluid communication with the outlet chamber 108. A secondary stopper 124 is coupled to the distal end of the secondary plunger 114. The secondary stopper has a distal surface 126 facing the distal end 104 of the barrel 98.

[0061] refer to Figure 10-12, the isolation valve 96 includes a spring-loaded shaft-mounted needle valve 128 disposed in a tubular main plunger 112 and a mating seat 130 formed in the through hole 122 of the main stop. In some embodiments, the needle valve 128 and the seat 130 have a Luer connector profile. The spring 132 biases the needle valve 128 away from the seat 130, maintaining the isolation valve in an open position; this allows fluid to flow from the secondary chamber 94 into the main chamber 92 and the outlet 108. The main plunger 112 defines at least one cam groove 134 having an open engagement surface portion 136 and a closed engagement surface portion 138, and a radially protruding cross pin 140 of the shaft of the needle valve 116 is constrained in the cam groove 134. The isolation valve 96 is closed by twisting and then pressing a grooved knob 142 on the shaft of the needle valve 128 out of the open engagement surface 136 of the cam groove 134. This compresses the spring 132 and pushes the needle valve 128 into mating contact with the corresponding seat 130, thereby closing the valve and isolating the secondary chamber 94 from the main chamber 92 and the outlet 108 of the luer connector 106. The needle valve 128 is locked in its closed position by twisting the grooved knob 142 so that the cross pin 140 of the isolation valve 96 engages and is trapped within the closed engagement surface 138 of the cam groove 134. In some embodiments, the main plunger 112 has three cam grooves 134, and there are three corresponding cross pins 140 on the isolation valve 96. An annular shaft seal 144 prevents fluid from leaking between the elongated stem of the isolation valve 96 and the main plunger 112. The shafts of the main plunger 112 and the needle valve 128 are sized to inhibit flexure of the shafts and maintain vertical alignment of the needle valve tip and its mating seat 130.

[0062] When the syringe 90 is used, the secondary chamber 94 is pre-filled with fluid, wherein the isolation valve 96 is in a closed position to prevent leakage of the fluid. Alternatively, the secondary chamber 94 is filled on-site at the treatment center. If the latter, before filling the syringe 90, the isolation valve 96 is opened; both the main stopper 116 and the secondary stopper 124 are fully advanced together with the main plunger 112 and the secondary plunger 114, so that the distal surface 120 of the main stopper 116 abuts the distal end 104 of the barrel 98, and the distal surface 126 of the secondary stopper 124 abuts the proximal surface 118 of the main stopper. Now, both the main chamber 92 and the secondary chamber 94 have been compressed to a zero volume state. In order to aspirate and fill the empty secondary chamber 94, the secondary plunger 114 is retracted, while the main plunger remains in its fully advanced position. The plunger stopper 146 protrudes radially into the interior of the barrel 98 to prevent the main plunger 112 and the secondary plunger 114 from being accidentally separated from the barrel. When the secondary chamber 94 is filled to the desired capacity, the isolation valve 96 is closed, thereby isolating its contents. Thereafter, the primary chamber 92 is aspirated by retracting the main plunger 112. In some applications, the syringe 90 is used to reconstitute a powdered drug that has been pre-filled in the primary chamber 92 by dispensing a pre-filled diluent liquid stored in the secondary chamber 94 into the primary chamber. In other applications, after opening the isolation valve 96, the drug is aspirated and dispensed into the VAD with the primary chamber 92, and the VAD is subsequently flushed with a flushing solution stored in the secondary chamber 94.

[0063] exist Figure 13-16 Another aspect of the present disclosure is shown in which a dual chamber syringe 150 has a main chamber 152 and a secondary chamber 154 of variable volume in series, axially aligned and oriented. The secondary chamber 154 is contained within a main plunger 172. A one-way duckbill valve 156 facilitates the discharge of fluid from its secondary chamber 154. The duckbill valve 156 has a Figure 2 and Figure 3 It is similar in construction and operation to the duckbill valve 76 of the syringe 150; it does not allow fluid to flow back or reverse into the secondary chamber 154. As with the previously described syringe embodiments, in one or more embodiments of the syringe 150, the main chamber 152 and / or the secondary chamber 154 are pre-filled with one or more fluids, such as flushing fluid or medication.

[0064] The syringe 150 includes a substantially cylindrical barrel 158 defining an inner sidewall 160. The barrel 158 has an open proximal end 162 and a distal end 164. The distal end 164 of the barrel 158 includes a Luer connector 166 defining an outlet chamber 168 therethrough. The outlet chamber 168 is in fluid communication with an interior 170 of the barrel 158, wherein the interior is defined by the open proximal end 162, the distal end 164, and the inner sidewall 160.

[0065] The syringe 150 includes a nested main plunger 172 and a secondary plunger 174, which are disposed within the barrel interior 170 and have an integral main plunger rod and a secondary plunger rod, respectively, that are selectively translatable along a common axis within the barrel interior 170. The main plunger 172 has a hollow tubular configuration and includes a structure of the secondary chamber 154. Thus, when the main plunger 172 is advanced or withdrawn within the barrel interior 170, the secondary chamber 154 translates with the main plunger 172. In addition, the outer surface of the barrel 158 and / or the secondary plunger 174 may include measurement markings to indicate the amount of fluid contained therein.

[0066] refer to Fig.13 and Fig.16 , a main stopper 176 is coupled to the distal end of the main plunger 172. The main stopper 176 has a proximal surface 178 facing the open proximal end 162 of the barrel 158 and a distal surface 180 facing the distal end 164 of the barrel. The main stopper 176 defines a through hole 182 between its proximal surface 178 and the distal surface 180, wherein the hole is in fluid communication with the outlet chamber 168. A secondary stopper 184 is coupled to the distal end of the secondary plunger 174. The secondary stopper has a distal surface 186 facing the distal end 164 of the barrel 158 and a circumferential sealing skirt 188. The circumferential sealing skirt 188 is in friction-tight fluid-tight contact with the inner side wall 190 of the main plunger 172.

[0067] The variable volume main chamber 152 is defined within the boundaries of the distal end surface 180 of the main stopper 176, the distal end 164 and the inner sidewall 160 of the barrel 158, and the distal end surface 186 of the secondary stopper 184. The variable volume secondary chamber 154 is defined within the boundaries of the distal end surface 186 of the secondary stopper 184, the distal end 194 and the inner sidewall 190 of the tubular main plunger 172, and the distal end surface 186 of the secondary stopper 184. In operation, as shown in FIG. Figure 13-16 As shown, by retracting the secondary plunger 174 ( Fig.14 ), the empty main chamber 152 is aspirated and filled with the required fluid. The frictional contact between the circumferential sealing skirt 188 of the secondary stopper 184 and the opposing abutting inner side wall 190 of the main plunger 172 causes the latter plunger and its primary stopper 176 to translate toward the proximal open end 162 of the barrel 158. In order to prevent the main plunger 172 and the nested secondary plunger 174 from being accidentally separated from the barrel 158, the retraction of the two plungers is limited when the proximal surface 194 of the main plunger with an internal stop ring 196 is inserted into the open proximal end 162 of the barrel 158. Fig.15In the embodiment of the present invention, the fluid in the main chamber 154 has been discharged by advancing the secondary plunger 172 with sufficient force to advance the primary stopper 176 into contact with the distal end 164 of the barrel 158, but the advancement force is limited to a level below that required to open the duckbill valve 156. When it is necessary to discharge the contents of the secondary chamber 154, the secondary plunger 174 is advanced with sufficient force to open the duckbill valve 156, as previously explained with respect to the discharge of the secondary chamber 74 of the syringe 20 (see Figure 4 ). Thus, for embodiments of the syringe 158, by continuously advancing the secondary plunger 174 with sufficient force to open the duckbill valve 156, the clinician can automatically and sequentially deliver medication with the primary chamber 154 and then deliver flushing solution with the secondary chamber 154 without having to change syringes.

[0068] exist Fig.17 Another aspect of the present disclosure is shown, wherein a dual chamber syringe 200 has a serially connected, axially aligned and oriented, variable volume main chamber 202 and secondary chamber 204, which are formed in nested respective main barrel 206 and secondary barrel 208. A one-way umbrella valve 210 and a mating umbrella valve seat 212 are coupled to the secondary barrel 208; they serve as a primary stop and facilitate the storage of fluid in and discharge from the secondary chamber 204. The umbrella valve seat 212 defines a through hole 213. The umbrella valve 210 is oriented within the through hole 213, preventing fluid from flowing from the main chamber 202 to the secondary chamber 204, which isolates the contents of the secondary chamber from the rest of the syringe 200. As with the previously described syringe embodiments, in one or more embodiments of the syringe 200, the main chamber 202 and / or the secondary chamber 204 are each pre-filled with one or more fluids, such as a flushing fluid or a drug.

[0069] The substantially cylindrical main barrel 206 defines an inner sidewall 214, an open proximal end 216, and a distal end 218. The distal end 218 of the main barrel 206 includes a Luer connector 220 that defines an outlet cavity 222 therethrough. The outlet cavity 222 is in fluid communication with an interior 224 of the main barrel 206, wherein the interior is defined by the open proximal end 216, the distal end 218, and the inner sidewall 214. The variable volume main chamber 202 is defined within the inner sidewall 214, and the distal end 218 of the main barrel 208 and a main stopper including an umbrella valve 210 / umbrella valve seat 212.

[0070] The syringe 200 includes a nested main plunger and a secondary plunger pair that can selectively translate along a common axis within the interior 224 of the main barrel 206. The secondary barrel 208 serves as an integrated main plunger / integrated plunger rod disposed within the interior 224 of the main barrel. Therefore, the entire secondary chamber 204 translates with the secondary barrel because the secondary barrel serves as a main plunger to change the volume of the main chamber 202 within the main barrel 206. A retaining ring 228 adjacent to the open proximal end 216 of the main barrel 206 limits the retraction of the integrated secondary barrel / main plunger 208 to prevent the secondary barrel from accidentally separating from the syringe 200. The secondary plunger 226 includes an integral plunger rod that can selectively translate within the corresponding interiors of the main barrel 206 and the secondary barrel 208. In addition, the outer surface of the main barrel 206 and / or barrel 208 and / or the secondary plunger 226 may include measurement markings to indicate the amount of fluid contained therein.

[0071] A secondary stop 230 is coupled to the distal end of the secondary plunger 226. The secondary stop has a distal surface 232 facing the distal end 218 of the primary barrel 208. The variable volume secondary chamber 204 is defined within the boundaries of the distal surface 232 of the secondary stop 230, the inner sidewall 234 of the secondary barrel 208, and the umbrella valve seat 212. When in a locked state, the twist-lock mechanism selectively locks the secondary plunger 226 in its maximum retracted position relative to the secondary plunger barrel 208, so that the advancement pressure on the secondary plunger only translates the secondary barrel 208 to selectively change the volume of the primary chamber 202. The twist-lock mechanism includes a pair of opposing radially projecting lugs 336 formed on the secondary plunger 226 and a mating corresponding lug recess 240 formed in the inner sidewall 234 of the secondary plunger barrel 208. When the twist-lock mechanism is in the unlocked state, the lugs 336 of the secondary plunger 226 are not engaged in the mating lug recesses 240 of the secondary barrel 208, thereby allowing the secondary plunger and its attached secondary stop 230 to translate within the secondary barrel.

[0072] The secondary chamber 204 of the syringe 200 is advantageously pre-filled with a desired fluid, such as water. In some embodiments, the main chamber 202 is pre-filled with a dry powder drug, which is then mixed with a diluent fluid from the secondary chamber 204 by unlocking the locking mechanism and advancing the secondary plunger 226. The mixed drug is infused into the VAD by locking the secondary plunger 226 with the locking mechanism and advancing it together with the integrated secondary barrel / 208 main plunger. In other embodiments, the secondary chamber 204 of the syringe 200 pre-filled with a flushing solution and an empty main chamber 202 are provided. The main chamber 202 is selectively aspirated with a desired fluid such as a drug and discharged into the VAD. The VAD is then flushed with the flushing solution in the secondary chamber 204 by using the same syringe 200. Thus, for an embodiment of the syringe 200, a clinician can automatically and sequentially deliver medication into the VAD and then flush the VAD by: (i) advancing the secondary plunger 226 when in a locked state, thereby expelling the primary chamber 202 filled with medication into the VAD, (ii) unlocking the secondary plunger using a simple twisting motion, and (iii) depressing the unlocked secondary plunger to expel the secondary chamber 204 filled with flushing solution into the VAD, all without requiring replacement of the syringe.

[0073] The syringe embodiments disclosed herein are made of medical grade materials known to those skilled in the art. In some embodiments, the barrel, plunger and shaft described are made of polypropylene polymers. The seal is made of a fiber-filled polytetrafluoroethylene (PTFE) polymer. The stopper is made of a polyisoprene polymer. The spring is made of stainless steel.

[0074] The reference to "one embodiment", "certain embodiments", "various embodiments", "one or more embodiments" or "embodiments" in this specification means that the specific features, structures, materials or characteristics described in relation to the embodiment are included in at least one embodiment of the present disclosure. Therefore, phrases such as "in one or more embodiments", "in certain embodiments", "in various embodiments", "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily refer to the same embodiment of the present disclosure. In addition, specific features, structures, materials or characteristics may be combined in one or more embodiments in any suitable manner. In addition, it will be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive. "Including", "including" or "having" and variations thereof used herein are meant to include the items listed thereafter and their equivalents and additional items. Unless otherwise specified or limited, the terms "mounting", "connecting", "supporting" and "coupling" and variations thereof are to be interpreted broadly; they include direct and indirect mounting, connection, support and coupling. In addition, "connecting" and "coupling" are not limited to physical, mechanical or electrical connections or couplings.

[0075] Although the disclosure herein provides descriptions with reference to embodiments, it should be understood that these embodiments merely illustrate the principles and applications of the present disclosure. It is apparent to those skilled in the art that various modifications and variations may be made to the present disclosure without departing from the spirit and scope of the present disclosure. Therefore, the present disclosure is intended to include modifications and variations within the scope of the appended claims and their equivalents. The appended claims are not limited to the construction details and component arrangements of the exemplary embodiments set forth in the specification or shown in the drawings.

Claims

1. A syringe, characterized in that include: a cylindrical barrel defining an inner sidewall, the barrel having an open proximal end and a distal end, the distal end of the barrel comprising a connector defining an outlet chamber therethrough, the outlet chamber being in fluid communication with an interior of the barrel defined by the open proximal end, the distal end, and the inner sidewall; a concentrically nested primary and secondary plunger disposed within the barrel interior and having a primary and secondary plunger rod, respectively, selectively translatable along a common axis within the barrel interior; a main stopper coupled to a distal end of the main plunger, the main stopper having a proximal surface facing the proximal end of the barrel and a distal surface facing the distal end of the barrel, the main stopper defining a through hole between the proximal and distal surfaces thereof, the through hole being in fluid communication with the outlet chamber; a secondary stopper coupled to a distal end of the secondary plunger, the secondary stopper having a distal surface facing the distal end of the barrel; a resealable valve disposed within the barrel interior and axially offset along the common axis away from the distal surface of the secondary stop toward the distal end of the barrel, the resealable valve having a valve inlet in fluid communication with the distal surface of the secondary stop and an outlet in fluid communication with the through hole of the primary stop and the outlet chamber; an annular primary fluid chamber defined within the barrel interior between the distal surface of the primary stopper and the distal end of the barrel, the volume of the primary fluid chamber being selectively variable by translation of the primary plunger rod; as well as a secondary fluid chamber nested within the primary fluid chamber and defined within the barrel interior between the distal end surface of the secondary stopper and the valve inlet, in fluid communication with the valve inlet, the volume of the secondary fluid chamber being selectively variable by translation of the secondary plunger rod; wherein when the valve is closed, the secondary fluid chamber is isolated from the outlet chamber such that translation of the primary plunger rod draws fluid into or dispenses fluid out of the primary fluid chamber only via the outlet chamber; and Wherein, when the valve is open, the secondary fluid chamber is in fluid communication with the outlet chamber, so that translation of the secondary plunger rod dispenses fluid out of the secondary fluid chamber via the outlet chamber.

2. The syringe according to claim 1, characterized in that The valve includes a one-way valve that prevents fluid from being drawn into the secondary fluid chamber.

3. The syringe according to claim 2, characterized in that The valve comprises a duckbill type valve.

4. The syringe according to claim 1, characterized in that The secondary plunger rod is selectively coupled to the secondary plunger when dispensing fluid from the secondary fluid chamber.

5. The syringe according to claim 4, characterized in that Also included is the secondary plunger rod selectively coupled to the secondary plunger using mating male and female threads.

6. The syringe according to claim 1, characterized in that The secondary fluid chamber is pre-filled with fluid.

7. The syringe according to claim 1, characterized in that Also included is an inner surface of the distal end of the barrel, the inner surface defining a seat surface for abutting engagement with the distal end surface of the main stop when the main stop is fully advanced within the barrel, thereby isolating the main fluid chamber from the outlet cavity and the outlet of the valve.

8. The syringe according to claim 7, characterized in that It also includes an inner surface of the distal end of the secondary fluid chamber defining a seat surface, and when the secondary stopper is fully advanced in the barrel, the seat surface of the secondary fluid chamber is used to abut and engage with the distal end surface of the secondary stopper, thereby isolating the secondary fluid chamber from the outlet cavity and the outlet of the valve.

9. The syringe according to claim 1, characterized in that The inner surface of the distal end of the secondary fluid chamber defines a seat surface, and when the secondary stopper is fully advanced in the barrel, the seat surface is used to abut and engage with the distal end surface of the secondary stopper, thereby isolating the secondary fluid chamber from the outlet cavity and the outlet of the valve.

10. A syringe, characterized in that include: a cylindrical barrel defining an inner sidewall, the barrel having an open proximal end and a distal end, the distal end of the barrel comprising a connector defining an outlet chamber therethrough, the outlet chamber being in fluid communication with an interior of the barrel defined by the open proximal end, the distal end, and the inner sidewall; an inner barrel having a distal tip adjacent the distal end of the barrel and nested in radially spaced relationship within the barrel; a concentrically nested primary and secondary plunger disposed within the barrel interior and having primary and secondary plunger rods, respectively, selectively translatable along a common axis within the barrel interior, wherein the primary plunger surrounds the inner barrel and the secondary plunger is nested within the inner barrel; a main stopper coupled to the distal end of the main plunger, the main stopper having an annular cross-section, a proximal surface facing the proximal end of the barrel and a distal surface facing the distal end of the barrel, the main stopper defining a through hole between the proximal and distal surfaces thereof for receiving the inner barrel therein, the main stopper being in fluid communication with the outlet chamber; a secondary stopper coupled to a distal end of the secondary plunger, the secondary stopper having a distal surface facing the distal end of the barrel; an annular main fluid chamber; and a resealable valve disposed within the barrel interior and axially offset along the common axis toward the distal end of the barrel away from the distal surface of the secondary stopper, the resealable valve having a valve inlet coupled to the distal top end of the inner barrel and an outlet in fluid communication with the through hole of the primary stopper and the outlet chamber, the valve inlet in fluid communication with the distal surface of the secondary stopper, the valve selectively isolating a secondary fluid chamber from the outlet chamber and the primary fluid chamber; wherein the primary fluid chamber is defined within the distal surface of the primary stopper, the distal end of the barrel, the inner sidewall of the barrel, and the outer sidewall of the inner barrel, the volume of the primary fluid chamber being selectively variable by translation of the primary plunger rod; wherein the secondary fluid chamber is defined within the distal surface of the secondary stopper, the distal top end of the inner barrel and the inner side wall of the inner barrel, the distal top end of the inner barrel comprising the valve inlet, the secondary fluid chamber being in fluid communication with the valve inlet, and the volume of the secondary fluid chamber being selectively changeable by translation of the secondary plunger rod; wherein when the valve is closed, the secondary fluid chamber is isolated from the outlet chamber such that translation of the primary plunger rod draws fluid into or dispenses fluid out of the primary fluid chamber only via the outlet chamber; and Wherein, when the valve is open, the secondary fluid chamber is in fluid communication with the outlet chamber, so that translation of the secondary plunger rod dispenses fluid out of the secondary fluid chamber via the outlet chamber.

11. The syringe according to claim 10, characterized in that The valve comprises a one-way valve.

12. The syringe according to claim 11, characterized in that The valve comprises a duckbill type valve.

13. The syringe according to claim 10, characterized in that The main plunger includes a tubular profile.

14. The syringe according to claim 10, characterized in that Also included is an inner surface of the distal end of the barrel, the inner surface defining a seat surface for abutting engagement with the distal end surface of the main stop when the main stop is fully advanced within the barrel, thereby isolating the main fluid chamber from the outlet cavity and the outlet of the valve.

15. The syringe according to claim 14, characterized in that It also includes an inner surface of the distal end of the secondary fluid chamber defining a seat surface, and when the secondary stopper is fully advanced in the barrel, the seat surface of the secondary fluid chamber is used to abut and engage with the distal end surface of the secondary stopper, thereby isolating the secondary fluid chamber from the outlet cavity and the outlet of the valve.

16. The syringe according to claim 10, characterized in that The inner surface of the distal end of the secondary fluid chamber defines a seat surface, and when the secondary stopper is fully advanced in the barrel, the seat surface is used to abut and engage with the distal end surface of the secondary stopper, thereby isolating the secondary fluid chamber from the outlet cavity and the outlet of the valve.

17. The syringe according to claim 10, characterized in that The secondary plunger rod is selectively coupled to the secondary plunger when dispensing fluid from the secondary fluid chamber.

18. The syringe according to claim 17, characterized in that Also included is the secondary plunger rod selectively coupled to the secondary plunger using mating male and female threads.

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