Low-cost syringes with durable and disposable components

Abstract

To provide low cost insulin injection syringes.SOLUTION: Low cost insulin injection syringes 20 are disclosed in which the low cost is achieved by separating the syringe 20 into two types of components, the two types of components being reusable components, - an outer sleeve 24 and a syringe plunger 32 -, that do not contact a fluid path and are durable, and single-use components that contact the fluid path and are not reused. The ability to reuse the durable components reduces the effective per-unit cost of the syringe 20. The disposal burden is reduced because not all of the components of the syringe 20 need to be disposed of each time the syringe 20 is used.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 62 / 611,876, filed December 29, 2017, which is expressly incorporated by reference herein in its entirety.

[0002] FIELD OF THEINVENTION The present invention relates generally to syringes for transferring (i.e., injecting or withdrawing) fluids. In particular, but not by way of limitation, embodiments of the present invention relate to low-cost insulin injection syringes, where the low cost is achieved by separating the syringe into two types of components: a durable component that does not contact a fluid pathway and can be reused, and a disposable or single-use component that contacts a fluid pathway and is not reused. Methods for manufacturing, using, and packaging such syringes are also disclosed and claimed herein. [Background technology]

[0003] 2. Background of the Invention Most syringes in use today are disposable or single-use types. A typical disposable syringe is made primarily of plastic and has several important components. The largest and contains the most material is the plastic barrel. Printing graduations on the barrel is a critical and costly assembly step required to ensure proper administration by the user. Inside the barrel is a rubber stopper that creates a hermetic seal and is used to move liquid medications and other liquids in and out of the barrel. A plastic plunger rod interacts with the rubber stopper to move it back and forth under the user's control. Usually, but not always, a metal needle or cannula is attached to the distal end of the barrel, allowing liquids to be injected into or removed from the body. For example, a syringe with a male Luer connector at its distal end can be attached to the female Luer connector of a catheter or IV line to inject or withdraw fluids without the use of a needle or cannula.

[0004] In the management of diabetes, disposable plastic syringes are often used to administer liquid insulin to the user several times a day. These single-dose syringes typically have a clear polymer barrel with printed graduation numbers that allow the user to withdraw a precise dose of insulin from a vial, and a fine gauge metal needle (usually about 6-12 mm long) that injects the dose into the skin with minimal discomfort to the user. The needle may be removably connected to the barrel using a Luer-Lok® or Luer slip connection, or may be permanently attached or "fixed" to the barrel during the manufacture of the syringe. Insulin syringes usually have a capacity of 1 ml or less (with barrel sizes of 0.3 ml, 0.5 ml, and 1.0 ml being common), and the graduation markings on the barrel represent the units of a particular type of insulin (e.g., U-100 or U-500 insulin). Insulin syringes may include safety features to prevent reuse of the syringe, to protect the used needle, or both. Because insulin syringes are used only once and a user typically needs several of them each day, they are commonly sold in boxes or bags containing multiple syringes. Summary of the Invention [Problem to be solved by the invention]

[0005] In the above types of insulin syringes, there are no durable (reusable) components. The entire syringe is discarded after one use, and no components are reused. Although disposal of single-use syringes is advantageous to ensure sterility and prevent the spread of blood-borne diseases, the cost of providing all of the required syringe components and assembly procedures for only one use is higher than desired. Discarded syringes also create a disposal burden in hospitals and other medical facilities because they cannot be mixed with other types of medical waste, but instead must be placed in dedicated sharps disposal containers. Thus, there is a need for a syringe that reduces the cost and disposal burden associated with single use, while maintaining the hygienic benefits of single-use syringes. [Means for solving the problem]

[0006] Summary of the Invention According to an embodiment of the present invention, a low-cost syringe is provided by separating the syringe into two types of components: durable components that do not contact the fluid path and can be reused, and disposable or single-use components that contact the fluid path and are not reused. The ability to reuse the durable components reduces the effective cost per unit of the syringe when multiple syringes are used. Because these components do not contact the fluid path, sterility is not affected. Disposal burdens are also reduced because not all components of the syringe need to be discarded each time the syringe is used.

[0007] In an embodiment of the invention, two different syringe components are provided as durable components: a reusable outer sleeve containing graduation markings for the syringe and a reusable syringe plunger. Syringes manufactured according to the invention may use one or both of these durable components.

[0008] More specifically, one aspect of the invention relates to a syringe that includes a barrel assembly having a disposable tubular insert and a reusable outer sleeve, the tubular insert forming a fluid reservoir and having a fluid opening at its distal end, and the reusable outer sleeve being removably received on an outer surface of the tubular insert and having visible graduation markings thereon; a stopper movably received within the tubular insert, the stopper sealing a proximal end of the tubular insert and movement of the stopper within the tubular insert causing fluid to move in and out of the tubular insert through the fluid opening; and a user-operable plunger coupled to the stopper, the stopper moving within the tubular insert thereby causing fluid to move in and out of the tubular insert through the fluid opening under user control.

[0009] In another aspect, the invention relates to a syringe that includes a disposable portion including a fluid reservoir having a fluid opening at a distal end thereof and a stopper movably received in the fluid reservoir, the stopper sealing a proximal end of the fluid reservoir and movement of the stopper within the fluid reservoir moving fluid in and out of the fluid reservoir through the fluid opening; and a reusable portion including a user-operable plunger removably connected to the stopper, causing the stopper to move within the fluid reservoir, thereby moving fluid in and out of the fluid reservoir through the fluid passageway under user control.

[0010] Additional aspects of the invention relate to methods of using syringes of the types described to transfer fluids, and to syringe multi-packs in which durable and disposable components of the syringes are packaged for sale or use.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS Aspects and advantages of embodiments of the present invention will be more readily understood from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 illustrates a syringe according to a first embodiment of the present invention using a collar lock between a disposable tubular insert and a reusable outer sleeve. [Figure 2A] FIG. 1 illustrates a syringe according to a first embodiment of the present invention using a collar lock between a disposable tubular insert and a reusable outer sleeve. [Figure 2B] FIG. 1 illustrates a syringe according to a first embodiment of the present invention using a collar lock between a disposable tubular insert and a reusable outer sleeve. [Figure 2C] FIG. 1 illustrates a syringe according to a first embodiment of the present invention using a collar lock between a disposable tubular insert and a reusable outer sleeve. [Figure 2D] FIG. 1 illustrates a syringe according to a first embodiment of the present invention using a collar lock between a disposable tubular insert and a reusable outer sleeve. [Diagram 3] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4A] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4B] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4C] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4D] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4E]FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Figure 4F] FIG. 13 shows a syringe according to a second embodiment of the invention, which uses a side lock between a disposable tubular insert and a reusable outer sleeve. [Diagram 5] FIG. 13 shows a syringe according to a third embodiment of the invention, which uses a bayonet lock between a disposable tubular insert and a reusable outer sleeve. [Figure 6] FIG. 13 shows a syringe according to a third embodiment of the invention, which uses a bayonet lock between a disposable tubular insert and a reusable outer sleeve. [Figure 7] FIG. 13 shows a syringe according to a fourth embodiment of the invention, which uses a twist lock between a disposable tubular insert and a reusable outer sleeve. [Figure 8] FIG. 13 shows a syringe according to a fourth embodiment of the invention, which uses a twist lock between a disposable tubular insert and a reusable outer sleeve. [Figure 9A] FIG. 9 shows a modified version of the syringe shown in FIGS. 7 and 8. [Figure 9B] FIG. 9B shows a disposable tubular insert used in the syringe of the embodiment of FIG. 9A. [Figure 9C] 9A-9C show a disposable tubular insert for use in the syringe of the embodiment of FIGS. 7-8. [Figure 9D] FIG. 9 is a front view of a reusable outer sleeve used in the syringe embodiment of FIGS. 7 and 8. [Figure 9E] FIG. 9 is a rear view of a reusable outer sleeve used in the syringe embodiment of FIGS. 7 and 8. [Figure 10] FIG. 13 illustrates a syringe according to a fifth embodiment of the invention employing a press lock between a disposable tubular insert and a reusable outer sleeve. [Figure 11A]FIG. 13 illustrates a syringe according to a fifth embodiment of the invention employing a press lock between a disposable tubular insert and a reusable outer sleeve. [Figure 11B] FIG. 13 illustrates a syringe according to a fifth embodiment of the invention employing a press lock between a disposable tubular insert and a reusable outer sleeve. [Figure 11C] FIG. 13 illustrates a syringe according to a fifth embodiment of the invention employing a press lock between a disposable tubular insert and a reusable outer sleeve. [Figure 11D] FIG. 13 illustrates a syringe according to a fifth embodiment of the invention employing a press lock between a disposable tubular insert and a reusable outer sleeve. [Figure 12] 1A-1C show two different embodiments of a stopper and reusable plunger assembly for use with any of the syringe embodiments described above or with a conventional syringe. [Figure 13] 1A-1C show two different embodiments of a stopper and reusable plunger assembly for use with any of the syringe embodiments described above or with a conventional syringe. [Figure 14] 13A-13C show how multiple syringe assemblies according to any of the above embodiments may be packaged for sale or use. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENTINVENTION Reference will now be made in detail to the embodiments of the invention as illustrated in the accompanying drawings, in which like reference numerals refer to like elements throughout. The embodiments described and illustrated herein illustrate but do not limit the invention, and the drawings are not drawn to scale relative to each other or to actual physical embodiments. Furthermore, it will be understood by those skilled in the art that the phraseology and terminology used herein is for purposes of description and should not be considered limiting. The use of "including," "comprising," or "having," and variations thereof, herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless otherwise limited, the terms "connected," "coupled," and "attached," and variations thereof, herein are used broadly and encompass direct and indirect connections, couplings, and attachments. Furthermore, the terms "connected" and "coupled," and variations thereof, are not limited to physical or mechanical connections or couplings. Furthermore, terms such as "upper," "lower," "bottom," "top," "distal," and "proximal" are relative and are used to aid in description, but are not limiting.

[0014] 1 and 2A-2D show a syringe 20 according to a first embodiment of the present invention. The syringe 20 includes a tubular barrel assembly including a disposable tubular insert 22 and a reusable outer sleeve 24 that is open at both ends and coaxially receives the insert 22. The disposable tubular insert is preferably made of a plastic (polymer) material, such as polypropylene, that can be inexpensively injection molded. The reusable outer sleeve 24 is also preferably made of a plastic material, such as polypropylene, polystyrene, polycarbonate, or ABS, but may also be made of a metal, such as stainless steel. In general, the reusable outer sleeve 24 is preferably made of a relatively hard and durable material, while the disposable insert 22 may be made of a thinner, less rigid material. The upper portion of the tubular insert 22 can be seen in the partially exploded view of FIG. 1. The lower portion of the tubular insert 22 is partially obscured by the outer sleeve 24 in FIG. 1, but is visible through an elongated rectangular slot 26 formed longitudinally in the outer sleeve 24. FIG. 2A shows the tubular insert 22 fully received in the outer sleeve 24, as it is when the syringe 20 is in use.

[0015] The tubular insert 22, shown alone in Figure 2B, is designed to be disposable and forms a fluid reservoir for fluid (not shown) to be injected or aspirated by the syringe 20. The volume of the fluid reservoir varies according to the position of a separate rubber stopper 28 that seals the proximal end of the insert 22. The stopper 28 is movably received within the tubular insert 22 for moving fluid in and out of the tubular insert 22 through a fluid opening 30 at the distal end of the tubular insert 22.

[0016] A plastic plunger 32 (shown in FIG. 1 but omitted from FIGS. 2A and 2B) having a distal end connected to the stopper 28 causes the stopper 28 to move up and down within the tubular insert 22, thereby moving fluid in and out of the tubular insert 22 through the fluid opening 30 under the control of the user. A thumb press 34 integrally formed at the proximal end of the plunger 32 allows the user to pull or push the plunger 32 as needed. A flange 36 with opposing arms is integrally formed near the proximal end of the tubular insert 22 and may be held by the user's fingers when manipulating the plunger 32. An annular collar 38 is integrally formed at the proximal end of the tubular insert 22 above the flange 36 to receive a removable sterile cap (not shown) that covers the proximal end of the syringe 20 prior to use. With the plunger 32 fully depressed, the thumb press 34 is slightly raised above the collar 38 so that the thumb press 34 may be grasped to manipulate the plunger 32.

[0017] In the illustrated embodiment, the fluid opening 30 is formed in a reduced diameter distal end portion 40 of the tubular insert 22 and is intended to receive a permanently attached or "fixed" needle or cannula (not shown). The use of a fixed needle may be advantageous to reduce fluid dead space within the insert 22. Alternatively, the distal end portion 40 may be formed as a male Luer slip or Luer Lock™ connector that allows the tubular insert 22 to be attached to a separately provided needle or cannula 42 via a hub 43. A Luer connector may also be used to directly couple the syringe 20 to a female Luer connector on a catheter or IV line without the use of a needle or cannula. In the case of a Luer Lock™ connector, the tapered Luer tip may be integrally formed with the insert 22 and the female threaded locking collar may be integrally formed with the sleeve 24. Alternatively, both portions may be integrally formed with the insert 22. Another possibility is to provide a snap fit between the hub 43 and the reduced diameter distal end portion 40 of the tubular insert, instead of a luer connection. The needle or cannula, whether separate or permanently attached, may be equipped with a sharp tip for skin penetration or pronator ventricle (PRN), or it may consist of a blunt cannula of the type used to access needleless connectors.

[0018] For cost reasons, the disposable tubular insert 22 is preferably devoid of any printed indicia, including printed graduation markings that are normally required for proper operation of the syringe 20, which would require a separate manufacturing step. Instead, the necessary graduation markings 44 are provided on the outer sleeve 24, which can be removed from the used syringe 20 and reused. The graduation markings 44 on the outer sleeve 24 can take the form of a combination of lines and numbers representing milliliters or units of insulin, as shown in FIGS. 1 and 2, or any other suitable form that may be required for a particular application. The graduation markings 44 can be ink or laser printed, embossed, engraved, laser etched, or a combination thereof (e.g., embossed with an overcoat of ink printing to enhance legibility). The embossing or engraving can be accomplished as part of the injection molding process used to manufacture the outer sleeve 24 (if it is made of plastic), with any desired ink printing being performed during a separate manufacturing step.

[0019] The longitudinal slots 26 in the outer sleeve 24 allow the user to view the transparent or translucent tubular insert 22 directly, so that the fluid level within the tubular insert 22 may be viewed and compared to the scale markings 44 on the outer sleeve 24. Due to the presence of the slots 26, it is usually preferred to manufacture the outer sleeve 24 transparent or translucent, so that the fluid level may be ascertained to some degree through its wall (although perhaps less clearly than through the slots 26), although the outer sleeve 24 may be manufactured partially or completely opaque, if desired. The slots 26 may be omitted if the outer sleeve 24 is sufficiently transparent or translucent, so that the fluid level within the tubular insert 22 may be viewed through the wall of the outer sleeve 24 with sufficient accuracy for proper dosing. Alternatively, the slots 26 may be replaced with a transparent or translucent window in embodiments in which the outer sleeve 24 is partially or completely opaque.

[0020] A removable connection is provided between the disposable tubular insert 22 and the reusable outer sleeve 24 so that the two components can be coupled together and used in the same manner as a conventional syringe, and then separated to allow reuse of the outer sleeve 24. This connection can be a simple friction or press fit between all or a portion of the cylindrical exterior surface of the tubular insert 22 and the cylindrical interior surface of the outer sleeve 24, or it can be a clamshell type connection if the sleeve 24 is split or hinged. However, given the importance of axially positioning the graduation markings 44 in such a way that they accurately and consistently represent the correct fluid volume within the tubular insert 22, a more accurate and reliable releasable locking arrangement would typically be desired. The locking function is primarily required axially, since this is the direction in which the fluid level is compared to the graduation markings 44, although in some applications a rotational lock (i.e., prevention of relative rotation between the tubular insert 22 and the outer sleeve 24) may also be required or desired.

[0021] One axial locking configuration, referred to as a collar lock, is shown in FIG. 1 and in FIGS. 2A-2D. In this arrangement, the tubular insert 22 seats at an annular rim 45 formed at the bottom of the sleeve 24 when it reaches its full insertion point within the sleeve. At this point, a separate collar 46 with internal threads 47, which is received in an externally threaded proximal end portion 48 of the sleeve 24, is rotated, thereby advancing it from position 49 on the sleeve 24 to a slightly more proximal position 50. The threaded end 47 has a slightly larger outer diameter at position 50 than it has at position 49. Cuts or gaps 51 divide the proximal end portion 48 into three or more relatively flexible portions. When the collar 46 is rotated to position 50, the increased diameter of the threaded end 47 allows these flexible portions to compress inwardly and grip the insert 22, thereby locking the sleeve 24 and the insert 22 together both axially and rotationally. In an alternative embodiment, the threaded end 47 has a slightly larger outer diameter at position 49 than it has at position 50, and the collar 46 is rotated and advanced from position 50 to position 49 to secure the sleeve 24 to the insert 22.

[0022] The user first receives the syringe 20 with the outer sleeve 24, either already attached or provided as a separate component that the user attaches to the insert 22 prior to use. If a needle or cannula 42 is required for the intended fluid transfer but is not pre-fixed or pre-attached to the insert 22, the user also attaches the necessary needle or cannula. The user then performs the fluid transfer, which may consist of aspirating a fluid (e.g., aspirating insulin from a vial), injecting a fluid into the body, delivering a fluid to a catheter or IV line, or withdrawing a fluid from the body (e.g., a blood sample), or some combination of these steps. In doing so, the user may observe the amount of fluid in the syringe 20 by comparing the fluid level visible through the slot 26 with the graduation markings 44 on the outer sleeve 24. Once the fluid transfer is complete, the user removes the outer sleeve 24 by unscrewing the collar 46 and discards the remainder of the syringe 20. The outer sleeve 24 and collar 46 may then be reused as part of another syringe 20 by attaching it to another insert 22 and repeating the above steps.

[0023] Several advantages of the disclosed syringe 20 will be apparent. For example, there is a reduction (perhaps up to 25%) in the cost per effective unit of the syringe because a labor-intensive manufacturing step (printing of the scale markings) is performed on a component of the syringe 20 (the outer sleeve 24) that can be used multiple times before being discarded. Such reuse does not compromise the sterility of the syringe because the outer sleeve 24 and collar 46 do not come into contact with bodily fluids or fluids transferred by the syringe 20. Another advantage is that the reusable outer sleeve 24 can be made of a sufficiently rigid material such as polycarbonate or even metal, reducing the rigidity required for the insert 22. In other words, because the insert 22 is snugly received in a closely fitting sleeve 24 that can provide some of the required strength, the walls of the insert 22 can be made thinner than would otherwise be required to withstand the internal fluid pressures generated by handling and injection by the user. This results in less waste of material when the insert 22 is discarded than would be the case with a conventional single-use syringe barrel.

[0024] 3 and 4A-4F show a syringe 20A according to a second embodiment of the invention (needle or cannula 42 is not shown in this or subsequent embodiments, but would normally be present). Syringe 20A is constructed much the same as syringe 20 of FIGS. 1 and 2, except that a different locking mechanism is provided between disposable tubular insert 22A and reusable outer sleeve 24A. In particular, flange 36A of insert 22A is received in a cavity of a correspondingly shaped receptacle 37 formed in the proximal end of sleeve 24A. In use, flange 36A and adjacent receptacle 37 together form a combined flange that may be held by a user's fingers. The underside of flange 36A has a distally facing cavity with a pair of shallow indentations 52 (visible in FIGS. 4B and 4C) that interact with sleeve collar 53 (shown alone in FIG. 4D). The sleeve collar 53 has two protruding cantilevered proximally extending arms 55 that are captured and fixed within the sleeve 24A and receptacle 37 and are flexible and normally outwardly biased. One end 57 of each arm 55 engages a corresponding indent 52 in the flange 36A while the other end protrudes through an opening 61 (visible in FIG. 4F) in the sleeve 24A. The engagement of the ends 57 of the arms 55 with the indents 52 in the flange 36A locks the sleeve 24A and the insert 22A together both axially and rotationally. The sleeve 24A and the insert 22A can be separated from one another after the syringe 20A has been used by squeezing the arms 55 inwardly to disengage the ends 57 of the arms from the indents 52 and then pulling the sleeve 24A and the insert 22A apart.

[0025] 5 and 6 show a syringe 20B according to a third embodiment of the present invention. The syringe 20B is constructed in much the same way as the syringes 20 and 20A of FIGS. 1-4F, except that a different locking mechanism is provided between the disposable tubular insert 22B and the reusable outer sleeve 24B. In particular, the insert 22B is molded with a laterally extending lug or protrusion 54, and the proximal portion of the reusable outer sleeve 24B has an open-ended L-shaped bayonet slot for slidably receiving the protrusion 54 to removably secure the sleeve 24B to the insert 22B by a combination of axial and rotational motion. The bayonet connection provides both an axial and partial rotational lock between the sleeve 24B and the insert 22B, which can be released by rotating the two components in opposite directions and displacing them axially. This allows the sleeve 24B and the insert 22B to be separated from each other after the syringe 20B has been used, so that the sleeve 24B can be reused.

[0026] 7 and 8 show a syringe 20C according to a fourth embodiment of the invention. In this embodiment, the flange 36C of the insert 22C is received in a cavity of a correspondingly shaped receptacle 52C formed in the proximal end of the sleeve 24C. The receptacle 52C has slots 58 in its front and rear side walls to receive the arms of the flange 36C when the insert 22C is rotated 90 degrees and pressed down against the sleeve 24 from the position shown in FIG. 7 to the position shown in FIG. 8. The receptacle 52C also has diagonally opposed side openings 60 in its front and rear side walls to frictionally receive and retain the arms of the flange 36C when the insert 22C is rotated another 90 degrees against the sleeve 24 from the position shown in FIG. 8. The top closure 62, 64 is positioned above the side opening 60 to prevent the insert 22C from being axially pulled out of the sleeve 24C following this second 90 degree rotation, and the closed side walls of the receptacle 52C prevent any further rotation of the insert 22C in the same direction. In this way, the insert 22C is both axially and rotationally locked within the sleeve 24C. The frictional engagement between the arms of the flange 36C and the side openings and walls of the receptacle 52C may be enhanced by providing bonding or interlocking structures (not shown) on these structures, if desired. The flange 36C and the adjacent receptacle 52C together form a mated flange that may be held by the user's fingers during use of the syringe 20C. The insert 22C and the sleeve 24C may be separated from each other after use of the syringe 20C by first rotating and then axially displacing them in opposite directions relative to each other. This allows the sleeve 24C to be reused and the remainder of the syringe 20C to be discarded.

[0027] The embodiment of FIG. 9A is similar to that of FIGS. 7 and 8, except that the length of the flange 36D has been reduced (truncated) to save additional material in the manufacture of the insert 22D. FIG. 9B shows the insert 22D of FIG. 9A removed from the outer sleeve 24D, more clearly showing the reduced length of the flange 36D. For comparison, FIG. 9C shows the insert 22C of FIGS. 7 and 8 with a full length flange 36C. FIGS. 9D and 9E are front and rear views of the reusable outer sleeve 24C of FIGS. 7 and 8 as it would appear when removed from the disposable insert 22C. The reusable outer sleeve 24D of FIG. 9A would have essentially the same appearance.

[0028] 10 and 11A-11D show a syringe 20E according to a fifth embodiment of the present invention. The syringe 20E is constructed much the same as the syringes 20-20D of FIGS. 1-9E, except that a different locking mechanism is provided between the disposable tubular insert 22E and the reusable outer sleeve 24E. In particular, the proximal portion of the disposable tubular insert 22E has a pair of diametrically opposed lateral projections or studs 66, 68, and the proximal portion of the reusable outer sleeve 24E has an expandable section including a pair of opposed deflectable flaps 70, 72 having channels 71 and holes 73 for receiving the projections 66, 68. During initial assembly of the syringe 20E, as the outer sleeve 24E is advanced proximally over the exterior surface of the tubular insert 22E, the projections 66, 68 slide into the channels 71 and eventually into the holes 73 to removably secure the sleeve 24E to the insert 22E. This holds sleeve 24E and insert 22E together in an axially and rotationally locked condition. After syringe 20E has been used, sleeve 24E and insert 22E can be separated from one another by pressing fastening tabs 75, which bends flaps 70, 72 outward and disengages holes 73 from projections 66, 68. Sleeve 24E and insert 22E can then be pulled apart.

[0029] Figures 12 and 13 show two different embodiments of a stopper and reusable plunger assembly 80, 80' for use in any of the syringe embodiments described above (i.e., in combination with a disposable insert 22 and a reusable outer sleeve 24) or for use in a conventional single-use syringe having no other reusable components. In each of Figures 12 and 13, the plunger 32, 32' is a durable plastic component that can be separated from the rubber stopper 28, 28' after use of the syringe and then reused as part of another syringe. Such reuse does not compromise the sterility of the syringe because the plunger 32, 32' does not come into contact with bodily fluids or fluids transported by the syringe.

[0030] Separation of the plunger 32, 32' from the stopper 28, 28' may be initiated by the user in a variety of ways, depending on the nature of the structural connection between these components. For example, if the distal end 82 of the plunger 32 includes an outer annular ring 84 that mates with an inner annular groove 86 in the stopper cavity 88, as shown in FIG. 12, separation may be accomplished by pulling the plunger 32 firmly in a proximal direction, while the stopper 28 is retained within the insert 22 by the user manually blocking the proximal opening of the insert 22 or by providing a constriction at the proximal opening of the insert 22 through which the stopper 28 may be forced upon initial assembly. Alternatively, as shown in FIG. 13, if the distal end 82' of the plunger 32' is provided with a raised helical thread 90 on its outer surface that mates with an internal helical groove 92 in the stopper cavity 88', separation may be accomplished by simply unscrewing the plunger 32' from the stopper 28'. The friction of the stopper 28' within the insert 22 will normally provide sufficient resistance to rotation of the stopper 28' to allow the plunger 32' to be unscrewed therefrom, but if this is not the case, the user may apply pressure by hand through the walls of the insert 22 and / or sleeve 24 to increase friction. Such application of pressure may also be used to assist in restraining the stopper 28 when the plunger 32 is removed by axial pulling in the embodiment of FIG. 12.

[0031] In all of the embodiments described, the stopper 28 is preferably placed at the proximal most end of the insert 22 prior to use. This positioning can be seen, for example, in Figures 9B and 9C. When the stopper 28 bottoms out and engages with the plunger tip, the user can push the stopper 28 distally with the plunger tip. Additionally, there can be a lubricant on the inside of the insert 22 to aid in the movement of the stopper 28. Placing the stopper 28 at the proximal end of the insert 22 first will better aid in the movement of the lubricant within the insert.

[0032] FIG. 14 illustrates one possible way in which a syringe 20 constructed according to any of the above embodiments may be packaged for use or sale. In the illustrated example, a plurality of inserts 22 (e.g., 10 inserts), having individual stoppers 28 but lacking some or all of the graduation markings necessary for proper use of the syringe, are packaged in a sealed plastic bag 100 along with a single reusable sleeve 24 and a single reusable plunger 32. After opening the bag, the user couples the sleeve 24 and plunger 32 (and a needle or cannula, provided separately, if required for the intended use) to one of the inserts 22 to form a first syringe 20, uses the first syringe 20, removes the sleeve 24 and plunger 32, and discards the insert 22 (including the stopper 28). The removed sleeve 24 and plunger 32 are then attached to another insert 22 to form a second syringe 20, which is used and then separated in the same manner. This process is repeated until the supply of inserts 22 is exhausted, at which point the sleeve 24 and plunger 32 may also be discarded.

[0033] It will be apparent that variations are possible in which only one of the sleeve 24 and plunger 32 is reusable, in which case the other components are provided separately for each insert 22 (as in the case where the plunger 32 is not reused) or not provided at all (as in the case where the insert 22 is provided with direct scale markings and does not require a separate outer sleeve 24). It will also be apparent that variations are possible in which more than one reusable sleeve 24 and / or plunger 32 is provided in the bag 100 (e.g., two or more reusable outer sleeves 24 having different types of scale markings 44 for different types of insulin), or in which a box or other form of packaging is used in place of the bag 100. The ratio of disposable to reusable components may be higher than 10:1 (e.g., 50:1, 100:1, or higher), and the reusable components may be packaged separately from the disposable components, if desired.

[0034] Syringes 20 constructed in accordance with the present invention may be used in any application where it is desirable to inject, withdraw or transfer a fluid, including the administration of insulin and other liquid medications, the withdrawal of blood and other bodily fluids for sampling purposes, and the transfer of fluids for non-medical purposes.

[0035] Although only a few embodiments of the present invention have been shown and described, the present invention is not limited to the described embodiments. Instead, those skilled in the art will recognize that changes can be made to these embodiments without departing from the scope of the present invention. Furthermore, any of the embodiments, features and / or elements disclosed herein may be combined with each other to form various additional combinations not specifically disclosed, so long as the combined embodiments, features and / or elements are not mutually inconsistent. All such modifications and combinations are considered to be within the scope of the present invention, as defined by the appended claims and their equivalents.

Claims

1. a disposable portion including a fluid reservoir having a fluid opening at a distal end thereof and a stopper movably received within the fluid reservoir, sealing a proximal end of the fluid reservoir and causing movement of the stopper within the fluid reservoir to move fluid into and out of the fluid reservoir through the fluid opening; a reusable portion including a user operable plunger removably connected to the stopper to cause the stopper to move within the fluid reservoir, thereby moving fluid into and out of the fluid reservoir through a fluid passageway under user control, the reusable portion further including an outer sleeve having a longitudinal slot through which the fluid level in the disposable fluid reservoir can be viewed.

2. 10. The syringe of claim 1, further comprising a thumb press at a proximal end of the plunger.

3. 10. The syringe of claim 1, further comprising an annular collar at a proximal end of the fluid reservoir.

4. 10. The syringe of claim 1, further comprising a luer connector at the fluid opening of the fluid reservoir.

5. 10. The syringe of claim 1, further comprising a hollow needle or cannula at the fluid opening of the fluid reservoir.

6. 10. The syringe of claim 1, wherein the fluid reservoir includes a disposable insert removably received within a reusable outer sleeve having visible graduation markings.

7. performing a first fluid transfer using a first syringe comprising the syringe of claim 1; removing a reusable plunger and a reusable outer sleeve of the first syringe from a disposable portion of the first syringe after the first fluid transfer is completed; Providing a second disposable portion; attaching the second disposable portion to the reusable plunger and the reusable outer sleeve of the first syringe to construct a second syringe; A method of performing first and second fluid transfers, comprising performing a second fluid transfer using the second syringe.

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