WO1992005821A2

WO1992005821A2 - Safety syringe needle device with interchangeable and retractable needle platform

Info

Publication number: WO1992005821A2
Application number: PCT/CA1991/000321
Authority: WO
Inventors: Laurel A. Novacek; Fraser R. Sharp; Donald A. Mclean
Original assignee: Patco Ventures Ltd.
Priority date: 1990-10-03
Filing date: 1991-09-10
Publication date: 1992-04-16
Also published as: AU8444991A; EP0551287A1; JP3316213B2; DK0551287T3; PL170587B1; MX9101086A; DE69124525D1; DE69124525T2; ATE148351T1; GR3023262T3; WO1992005821A3; EP0551287B1; ES2099752T3; JPH06501173A; US5112318A

Abstract

The syringe includes a barrel (12), a plunger (14), and an adapter (24) for mounting the needle (16) in the distal end of the barrel. The adapter includes a protrusion (40) projecting away from the needle end and into the barrel defining an annular space between the barrel and the protrusion. The plunger and protrusion have complementary surfaces whereby the plunger may grip the adapter for removal of the adapter into the interior of the barrel after use. The adapter includes vent passages (60) communicating between the central passage (42) through the adapter and the annular space whereby air can be vented from the barrel after receiving fluid within the barrel and prior to injection. Thus, the syringe may be oriented in a vertical position needle end uppermost with the vent passages forming the most superior portion of the barrel interior whereby air may be vented.

Description

SAFETY SYRINGE NEEDLE DEVICE WITH INTERCHANGEABLE AND RETRACTABLE NEEDLE PLATFORM

FIELD OF THE INVENTION

This invention relates to a novel safety disposable syringe needle for medical and industrial application and particularly to a syringe which, after being used by a person to inject medication or fluid into a patient, or withdraw fluids from a patient or after sampling or exposure to toxic materials, or the like, can be transformed to withdraw the needle into the syringe barrel for disposal purposes, thereby eliminating needle stick injuries.

BACKGROUND OF THE INVENTION

Needle stick injuries, e.g., among medical personnel such as health care workers are of growing concern because of disease transmission, particularly the deadly virus known as HIV-1 (AIDS) and Hepatitis B. The AIDS virus for which there is no known cure is estimated to infect more than twenty million people worldwide and is spreading rapidly. It has been demonstrated statistically that the risk of acquiring HIV-1 infection is 0.35 - 0.74% per needle stick injury. This is due, in part, because the HIV virus can survive at room temperature on a needle for up to a week after injection. Transmission rates of Hepatitis B after needle stick exposure are much higher than that occurring with the HIV virus and may be 6 -.30%.

With presently used syringes with projecting needles, potentially dangerous needle stick injuries are commonplace and most often occur between the time medication is injected into the patient and the time the syringe is disposed of. Most injuries occur while recapping the needle or when disposing of it into a disposal container. However, maintenance personnel who handle disposed materials are also subject to needle stick injuries.

SUMMARY OF THE INVENTION

This invention relates to a safety disposable syringe. More particularly, this invention pertains to a syringe comprising: (a) a hollow elongated barrel; (b) an adapter in removable engagement with an end of the barrel; (c) a plunger adapted to fit within and move axially in the hollow barrel, the plunger causing a pumping action within the interior of the barrel between the plunger and the end of the barrel when the plunger is. pushed into the interior of the barrel in the direction of the end of the barrel; (d) an air and fluid venting system for venting the barrel when filled with fluid to eliminate air within the barrel prior to injection; and (e) engagement structures at the end of the plunger proximate to the adapter for engaging the adapter by a reversible axial coupling .and a unidirectional rotary coupling when the plunger is fully inserted into the interior of the barrel in the direction of the end of the barrel and causing the adapter to part from the barrel end and to be withdrawn into the interior of the barrel when the plunger is withdrawn away from the end of the barrel.

Thus, a feature of the present invention resides in venting structures in the adapter for venting air and fluid from the interior of the barrel once the barrel has been substantially filled with fluid to be injected and prior to injection. It is important that air be expelled entirely from the barrel so that air may not be injected with the fluid and equally important to allow more accurate dose measurement. In a preferred embodiment hereof, the adapter has a connective structure which enables the plunger to grasp the adapter and withdraw the adapter and needle into the interior of the barrel. This connective structure protrudes towards the interior of the barrel, forming an annular space between it and the side walls of the barrel at the barrel's distal end. That is, the adapter opening into the interior of the barrel is located spaced from the distal end of the barrel. Air can thus be trapped in such annular space upon movement of the plunger toward the distal end of the barrel. That is, the fluid in the barrel may occlude the central passage through the adapter, and prevent the air trapped in the annular space from venting.

To prevent this, the adapter is provided with one or more vent passages which open into the annular space at the most superior portion of the hollow barrel when the syringe is oriented substantially vertically with the needle uppermost. Consequently, after the fluid has been withdrawn into the interior of the barrel and the syringe oriented vertically needle end up, air is expelled through the vent passage into the central passage by moving the plunger toward the distal end of the barrel. The central passage may extend wholly through the adapter whereby the vent passage forms one or more branch passages of the central passage. Alternatively, the central passage may terminate within the adapter with the one or^"more vent passages serving not only as air vents but passages for flowing the fluid through the needle during injection. To ensure that the vent passage(s) opens at the superior position in the interior of the barrel, the face of the radially enlarged portion of the adapter facing the barrel interior may be tapered radially inwardly toward the needle end of the barrel. . Additionally, radial grooves, preferably rectangular in cross-section for ease of assembly, may extend in the tapered adapter face and constitute continuations of the vent passages. Eurther,. one.or.. ore annular grooves may be disposed in the tapered adapter face in communication with the radial grooves and vent passages, all to ensure venting of air from the syringe prior to use.

In a further embodiment of the syringe the plunger is hollow and is a circular cylinder in cross section with a fastening means such as threads at the finger press end of the plunger. The plunger additionally includes a narrowed weakened break point adjacent its opposite end whereby the hollow cylindrical portion of the plunger upon being withdrawn from the barrel may be broken away and fastened to the opposite end of the barrel whether or not the needle assembly has been withdrawn into the interior. Such construction allows for redundant manners of sheathing the needle assembly through the use of a needle guard or the cylindrical portion of the plunger. Both include threaded ends of the same size for attachment to the barrel and are relatively larger and more safely used than prior devices. Some additional features improve syringe function, for example, by enhancing the readability of calibration markings and thus improving the accuracy of the syringe.

In a still further embodiment of the invention, the needle guard and the hollow cylindrical portion of the plunger are the same element. That is to say, the circular cylinder portion of the plunger includes at a narrowed intermediate point a reusable connection means in lieu of a break point. Such construction allows this portion of the plunger to be disconnected from the needle end portion of the plunger and used as a needle guard. Subsequently, this portion may be removed from the end of the barrel and reconnected to the needle end portion of the plunger. Moreover, such construction allows the interior of the syringe body to be sealed at both ends when the needle end portion of the plunger is withdrawn and the hollow cylindrical portion is in place on the barrel as a needle guard.

Additional features found in the further exemplary embodiments are the use of colored material for the plunger, which due to its close proximity to the inner surface of the barrel provides a less distorted or clearer background for viewing the barrel calibration markings. Still further, the inclusion of a radially linear surface on the interior far end of the plunger bung, as well as using bung material of the same color as the plunger, presents a single flat interface which dramatically improves the visualization of the calibration markings and the alignment of the end of the plunger with such markings. More accurate filling and delivery of contents is then possible.

Still further beneficial features include the use of annular ridges on the interior of the barrel and/or on the exterior of the plunger whereby the sealing ridges in combination with a needle guard attached to the Opposite end of the syringe maintains sterile conditions in the syringe interior prior to use and after use seals bacteria or other material within the body of the syringe.

Additional features include a cup-like annular lip or resilient pronged projections on the plunger adjacent the portion at the break point which are used in combination with the interior ridges of the barrel at the finger press end to deter the needle assembly from being completely withdrawn from the interior of the barrel means. Such elements also retain the needle assembly at the finger press end of the barrel. As an additional feature of the exemplary embodiments, the needle assembly includes an adapter-plunger connection which is designed to allow unidirectional torque only so as to prevent re-attachment of the adapter to the barrel means without the use of a special tool. Thus subsequent use of the needle once the adapter and barrel have separated is prevented in the absence of special tools or extraordinary measures.

A further feature hereof is that the syringe may be packaged and sterilized in bulk and not necessarily in individual packages. However, this does not prevent tampering or inadvertent disruption of seals and contamination. It is important, therefore, that the syringe embody tamperproof features. To that end, in one embodiment hereof, tamperproofing can be accomplished by applying a strip, of tape having adhesive along one face along the side of the syringe covering both the junctures of the needle guard and body of the syringe and the proximal end of the barrel and plunger. Thus, if the tape has been broken or is twisted or otherwise removed from the syringe, it would be evident that the seals at the opposite ends of the syringe have possibly been disrupted. Similarly, in another embodiment hereof, a tight shrink-wrap of plastic material may be provided about these junctures. Again, removal of the shrink-wrapped plastic material or a twisting or severing thereof would indicate a possible disruption of or tampering with the seals. In a further form of the invention, the syringe may be dipped into a plastic material in liquid form whereby a thin-film coating is applied to and solidified about the entire outer surface of the syringe, including the needle guard and projecting portion of the plunger. Consequently, sterility may be maintained, provided the thin-film plastic coating is not broken, while at the same time, disruption of or tampering with the seals at the aforementioned junctures is readily evident.

These and further objects and advantages of the present invention will become more apparent upon reference-to the following specification, appended claims and drawings. DRAWINGS

Figure 1 is a perspective view partially in phantom of a syringe, with an attached needle guard according to the present invention;

Figure 2 is a longitudinal cross-sectional view thereof;

Figure 3 is a perspective view partially in section of the adapter and the distal end of the plunger illustrating the mating relationship of these elements;

Figure 4 is an enlarged fragmentary cross-sectional view illustrating the adapter of Figure 3 disposed in the distal end of the barrel;

Figure 5 is a view similar to Figure 4 illustrating a further form of the adapter;

Figure 6 is a different side elevational view of the syringe in partial sectioned view and with the needle guard removed;

Figure 7 illustrates a manner in which the plunger may be rotated with respect to the barrel in order to disconnect the needle assembly from the barrel for withdrawal of the assembly into the barrel; Figure 8 is a cross-sectional view similar to Figure 2 but with the needle assembly unfastened from the distal end of the barrel and with the assembly withdrawn into the barrel;

Figure 9 is a cross-sectional view similar to that illustrated in Figure 8 but with the hollow cylindrical portion of the plunger broken away at the break point;

Figure 10 is a cross-elevational view partially in section with the hollow cylindrical plunger portion fastened to the distal end of the barrel after the cylindrical plunger portion has been broken away at the break point;

Figure 11 is an axial view illustrating a pair of resilient prongs used to engage a groove at the finger press distal end of the barrel for retaining the needle assembly in the retracted position in the barrel;

Figure 12 is a partial side view of the pronged latching device of Figure 11;

Figure 13 is a side elevational view partially in cross-section of a still further exemplary and presently preferred embodiment of the invention; Figure 14 is a cross-sectional view thereof taken along section line 14-14 of Figure 13;

Figure 15 is a detailed partial side elevation view of a portion of the plunger including its narrowed portion which contains the break point as illustrated in Figure 13;

Figure 16 is an enlarged cross-sectional view illustrating a portion of the radially linear interface between the adapter and the plunger bung;

Figure 17 is an enlarged partial sectional view of ridges and an intervening groove on the inside surface of the barrel at the distal end and a corresponding annular ridge on the exterior surface of the hollow portion of the plunger which cooperates with the annular barrel ridges for locking and sealing purposes;

Figure 18 is a side elevational view partially in cross-section of a still further embodiment of the invention;

Figure 19 is a side elevational view partially in section of the embodiment of Figure 18 illustrating the cylindrical plunger portion disconnected from the needle end portion of the plunger; Figure 20 illustrates a partial end view of the plunger taken along line 20-20 in Figure 19;

Figure 21 is a perspective view of one form of a tamperproof syringe constructed in accordance with the present invention;

Figure 22 is an enlarged fragmentary cross-sectional view with parts broken out illustrating another form of a tamperproof syringe;

Figure 23 is an enlarged side elevational view with parts broken out and illustrates the opposite ends of a syringe having a tamperproof coating according to the present invention;

Figure 24 is an enlarged fragmentary cross-sectional view of a further form of adapter and plunger coupling mechanism according to the present invention;

Figure 25 is a cross-sectional view thereof taken generally about on lines 25-25 in Figure 24; and

Figure 26 is a fragmentary cross-sectional view of a further modified form of the coupling between the plunger and adapter. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

This invention pertains to a syringe which, after being used by a health care worker or hazardous industries worker, or the like, to inject medication or fluid into a patient, or withdraw fluid from a patient, or in sampling toxic material, for example, in an industrial process, can be transformed by the worker to withdraw the needle into the barrel of the syringe for disposal purposes, thereby eliminating potentially harmful needle stick injuries among such workers. In industrial applications, the storage of a contaminated needle is similarly effected within the barrel to prevent further contamination of the environment or process.

With any of the various embodiments of the basic syringe design, the needle is retracted by the user into the interior of the body of the syringe immediately after it is withdrawn from the patient's body tissue, or after exposure to hazardous situations. Thus, the needle is not exposed for accidental contact at any time after the needle has contacted the potentially hazardous patient's body fluids, or other hazardous materials. This retraction feature eliminates the possibility of potentially dangerous needle stick injuries occurring with contaminated needles. Most disposable syringes can be used with a variety of interchangeable needles with different diameter and length connected to the needle barrel by a Luer connector, which may be of two types. One is a simple conical device which accepts the needle base, known as a Luer tip. To detach the needle, it is simply pulled off. The other connector type is known as a Luer lock. The Luer lock has a simple screw thread locking mechanism that permits the base of the needle to be screwed onto the syringe so that it cannot be pulled off without unscrewing. In this disclosure, the universal coupling, mechanism connecting the needle to the syringe will be referred to as a Luer lock version of the Luer connector unless otherwise indicated while the claims cover both the plain Luer tip and the Luer lock mechanisms.

Referring now to the drawings, particularly to Figures 1-3, there is illustrated a syringe, generally designated 10, comprised of a barrel 12, a plunger 14, a needle 16 attached to a Luer lock 18, and a needle guard 20. A finger press 22 is provided at the remote end of plunger 14. Also, at the end of the barrel remote from the plunger end thereof, there is provided an adapter 24 hich includes a tapered end 26 for receiving a Luer lock 28.

Referring particularly to Figures 3, 4 and 5, adapter 24 is generally cylindrical, having an annular section 28 for -butting against a shoulder 30 at the end of barrel 12. A reduced diameter section has an external thread, for example, a lefthanded thread 32, for engaging with mating threads 34 (Figure 4) on the reduced diameter end 36 of the barrel. For reasons which will become apparent, the reduced diameter end 36 is also externally threaded at 38.

Projecting axially from the opposite end of adapter 24 is a protrusion 40 which, when the adapter 24 is secured in the barrel end, projects into the interior chamber of barrel 12. Adapter 24 includes an axially extending tapered channel or passageway 42 for communicating between the interior of the barrel and the needle. Engagement structure extends about the external surface of protrusion 40 for engaging with a corresponding engagement structure on the plunger whereby the adapter may be removed from the barrel end and withdrawn, together with the needle, into the interior of the barrel. The engagement structure includes on the external surface of protrusion 40 non-jamming, fast-acting spiral threads or ramps 44, together with axially extending end stops 46. Below ramps 44 is an annular groove 48 which cooperates with the connecting structure on the end of the plunger.

Referring to Figure 3, the end of the plunger 14 includes a bung 50 formed of resilient material and which surrounds a mating engagement structure on the plunger end for engaging with the structure about protrusion 40. The engagement structure on the plunger includes ramps and end faces 52 and 54, respectively, complementary to the ramps 44 and end faces 46 on protrusion 40. At the distal end of the plunger, there is an inwardly projecting annular ring 56 for engaging in the annular groove 48. Thus, when the plunger is advanced within the barrel to engage protrusion 40, the complementary ramps 44 and 52 engage one another. Due to the slopes of the ramps 44 and 52, the plunger is rotated in one direction relative to the adapter upon axial movement of the plunger toward the adapter to engage the end faces 46 and 54 with one another. Further, rotation of the plunger in one direction causes a unidirectional torque to be applied to the adapter, enabling the adapter to be unthreaded from the barrel end. Plunger rotation in the opposite direction causes the end stops 54 and 46 to separate and the plunger to ratchet relative to the adapter.

In operation, and after injection, the plunger is advanced axially and guided by the engaging complementary ramps 44 and 52 to engage end stops 46 and 54. Further axial advancement causes full insertion of the plunger into the barrel to engage ridge 56 in groove 48. Further rotation of the plunger in one direction unthreads adapter 24 from barrel end threads 34 while maintaining the adapter attached to the plunger end by the engagement of ridge 56 and groove 48. Ridge 56 may be partially or wholly annular as desired.

To ensure that air from the interior of the barrel may be ejected therefrom prior to use of the syringe, there is provided, with reference to Figure 3, a pair of vent passages 60 extending radially from and in communication with the central axial passageway 42 through vents 61. These passages preferably extend in grooved portions formed in the face of the flange facing the proximal end of the barrel. Additionally, as illustrated in Figures 4 and 5, the face 64 of the adapter facing the proximal end is tapered radially inwardly in a direction toward the needle end of the barrel, for example, on the order of about 3°. Further, an annular trough or groove 66 is preferably formed in the tapered flange face about the base of protrusion 40. Groove 66 lies in coπwnunication with the radial grooves 60 and vents 61 extending into the central passageway 42. One or more additional annular grooves may also be provided, including about the outer margin of the tapered flange base or at intermediate radial positions. By grooving the face of the adapter and tapering that face, grooves 60 and 66 will assume the most superior position within the interior of the barrel when the syringe is oriented vertically with the needle uppermost. Consequently, when the plunger is advanced toward the needle end to vent air from the interior of the barrel, as customary, any air trapped within the annular space between the distal end of the barrel and protrusion 40 will vent through grooves 60, 66 and vents 61 into central passageway 42. Hence, the interior of the barrel may be purged of any air prior to injection. It will be appreciated that there may be only a single vent passage, although preferably at least two such passages diametrically opposed to one another are provided. More than two such passages may also be provided, preferably equally spaced about the axis of the adapter.

Referring now to the embodiment of Figure 5, the central passageway 42a terminates short of the distal end of the protrusion 40a. Consequently, central passage 42a communicates only with the one or more radially extending vents 61a and grooves 64a. In this form, not only do the vents 61a and grooves 64a form the superior positions when the syringe is oriented vertically with the needle uppermost to vent air from the barrel and particularly the annular space 65a between the barrel and protrusion 40a, but provide the sole passageways for egress of fluid from the interior of the barrel through the central passageway 42a during injection. The opening 67a in the end of protrusion 40a -is in the form of a multi-sided opening, e.g., a hex-shaped opening, for purposes of receiving a tool for assembling the syringe. Thus, a tool may be inserted through the opposite end of the barrel and received in opening 67a to thread the adapter onto the barrel.

Referring back now to Figures 1 and 2, it will be appreciated that needle guard 20 covers the needle and is affixed to the barrel by barrel threads 38 and complementary threads on the guard. Plunger 14 also includes internal threads 70 adjacent finger press 22, together with an annular ridge 72 for providing sealing engagement with a groove 74 formed internally along the distal end of the barrel.

Also, plunger 14 includes a narrowed portion 76 including a weakened break point 78, as well as a pair of resilient arms or prongs 80. Details of these elements are shown in Figures 11 and 12.

Once the syringe has been sterilized and assembled, as illustrated in Figure 2, with the needle guard in place forming a sealing engagement with the threaded barrel, as well as with the plunger in the position shown, forming a sealing engagement between elements 72 and 74, the interior of the structure is thus sealed at both ends, maintaining sterile conditions. Other forms of seals may be used. For example, friction fits or annular ridges and complementary grooves may be used. Note that the threads 38 accommodate both the threaded connection with needle guard 20 as well as the threaded connection with threads 70 of the hollow plunger portion once the plunger is broken away and^* connected to the end of the barrel, as illustrated in Figures 9 and 10.

After use, and with the adapter and plunger connected, as illustrated in Figure 2, the plunger may be rotated in the manner shown in Figure 7 to disconnect the adapter from the interior threads at the distal end of the barrel as previously described. An important feature of this engagement mechanism is that once the adapter has been disconnected at its threaded connection with the barrel, it, along with the remainder of the needle assembly, remain attached to the plunger portion through the snap connection formed by the ridge 56 and groove 48. Thereafter, the plunger and attached needle assembly may be withdrawn into the barrel.

Retraction of the contaminated needle into the. barrel after use prevents or substantially reduces the possibility of inadvertent needle stick injuries. Furthermore, it will be appreciated that once adapter 24 has been disconnected from the distal end of barrel 12, in the absence of extraordinary measures or the use of a special tool, the needle assembly and the adapter cannot be reassembled to the barrel and the syringe reused. Thus, attempts to reattach the adapter to the barrel for subsequent use, illicit or otherwise, is effectively prevented since the ramps (spiral grooves) and end stop faces of the adapter-plunger connection are shaped to prevent transfer of torque in a direction to attain reattachment of the adapter to the barrel by rotating the plunger in the direction opposite that illustrated in Figure 7.

In use, the exemplary embodiment of syringes as illustrated, are bulk packaged, sterilized, assembled structures of the nature generally illustrated in Figure 2. Initially, needle guard 20 is removed, the plunger and attached bung are withdrawn, and the proper dosage of fluid within the syringe body is adjusted using calibration markings (not shown) on the barrel in combination with the straight radial forward edge of the bung 50 to obtain a rapid and highly accurate measured reading of the contents. On conventional syringes the calibration markings, as well as the bung, are usually black, with the bung attached to a slightly opaque plunger that is normally of an X cross-section. Additionally, the leading edge of the bung is normally curved outwardly. Accordingly, neither rapid nor accurate readings are easily obtainable with such structure which includes two interfaces between the bung and the fluid contents and between the bung and the plunger. Such readings are additionally complicated by attempting to distinguish black calibration markings against a black bung. As previously noted, the forward surface of the bung 50 albeit annular is planar in the radial direction. Moreover, the coloration of the bung and plunger elements are the same so as to obtain a single interface. Moreover, the colors of the materials, as well as the calibration markings, are selected to be contrasting so as to significantly improve the accuracy as well as the speed with which measurements may be taken. As an additional important feature pertaining to rapid and accurate measurements, the cylindrical plunger portion is sized to be closely received in barrel 12, thus reducing diffraction and increasing visibility.

After use and when the plunger and needle assembly including adapter 24 are withdrawn to the position illustrated in Figure 8, the ends of the resilient arms 80 register in the annular groove 74 so as to retain the needle assembly and lower portion of the plunger in the position illustrated. Thereafter, cylindrical plunger portion 14a may be broken away at the plunger break point 78 in the manner illustrated in Figure 9. The narrowed portion of the plunger 76 adjacent break point 78 is circular in cross-section in Figure 11 but may take other shapes such as oval to enhance the ease with which portion 14a may be broken away. After portion 14a has been broken away, it may be attached to the threaded distal end of the barrel as illustrated in Figure 10. Thus, the needle assembly is locked in the barrel and by locking arm 80. Moreover, the bung serves, to seal one end of the barrel. Also, portion 14a of the plunger may be attached to the threaded end of barrel 12 by the illustrated threaded connection or by other well known snap-fit or friction-fit connections, for example. As illustrated in Figure 10, not only is the needle withdrawn to a position eliminating inadvertent needle sticks, but the barrel is sealed at both ends thus effectively preventing the escape of any toxic or contagious contents.

It will be appreciated that because plunger element 14a is hollow and is made sufficiently long as to encapsulate the needle assembly in the position illustrated in Figure 2, for example, should the adapter 24 malfunction and fail to separate from the barrel, the exposed needle assembly may nevertheless be covered by either needle guard 20 or by plunger portion 14a. In this regard because the needle guard, as well as the hollow plunger portion, have been made of approximately the same diameter as the threaded end of the barrel, both the needle guard and the plunger portion 14a may more safely be installed on the exposed needle. Accordingly, it will be seen that the present design includes redundancy features whereby even if the needle assembly fails to disengage and retract after use, it may nevertheless be covered in at least two other ways as discussed above, thus incorporating additional safety features.

A still further embodiment is illustrated in Figures 13 through 17. In this embodiment, barrel 12a of Figure 13 is substantially identical to barrel 12 of the previous embodiment and includes elements 90 which, as illustrated in greater detail in Figure 17, include two annular ridges and an intervening groove 91 on the inside surface at the finger press end of the barrel. As will be seen in Figure 17, the groove 91 of the barrel is designed to cooperate with annular ridge 92 included in plunger. As will be recognized, these parts can be reversed. That is to say, groove 91 can be included on the plunger and ridge 92 can be included on the barrel. These elements cooperate when engaged to form an effective seal at one end of the barrel so as to prevent ingress or egress of materials to the central portion of the syringe body until it is used. This seal along with the use of a needle guard of the nature illustrated with the embodiment of Figure 2, which may be threaded to the barrel, will completely seal both ends of the syringe body. Such sealing, as with the previous embodiment, will allow the syringe to be sterilized and then bulk packaged rather than individually packaged, but nevertheless retain internal sterility. Returning to Figure 16, barrel 12a includes an annular groove formed at 94 for receiving in sealing engagement an annular sealing ridge 96 included in adapter 24a. This groove can be formed in the barrel during manufacturing or, preferably, is formed by ridge 96 during assembly due to the resilience of the plastic barrel material. The embodiment of Figure 13 additionally includes modifications to the plunger. In this.embodiment, plunger portion 104, which is shown in greater detail in both Figures 14 and 15 includes an outer circumferential lip 102 which is sufficiently reduced in diameter as to snap past barrel ridges 90 and groove 91 on assembly, but will be retained at the innermost ridge when the plunger and needle assembly are withdrawn into the barrel.

Subsequent to withdrawing the plunger and needle assembly into the barrel, the cylindrical plunger portion 14a may be broken away at the reduced break point or notch 106 of portion 108. As with the previous embodiment, narrow portion 108 may be circular in cross section or have other shapes such as oval for aiding in breaking away plunger portion 14a.

After the plunger portion 14a has been removed, it may be joined to the distal threaded end of barrel 12a as previously described. Element 14a is designed to be attached to the distal barrel end, even if the adapter fails to disengage from the barrel and the needle fails to retract. Moreover, as with the embodiment of Figure 2, the threaded connections such as formed at 38 and 70 may be replaced with other connection means such as snap connections or friction fits of the nature previously described.

Additionally, as with the previously described embodiment, the bung as well as the plunger portions may have similar coloration which additionally contrasts with the coloration of the calibration markings (not shown) on the barrel. Such coloration, as well as the radially linear forward surface 110 as detailed in Figure 16, present a single fluid plunger interface with greatly enhanced visibility as well as accuracy for the reasons previously described.

A further modification to the embodiment of Figure 13 may be found in the further exemplary embodiment illustrated in Figures 18 through 20. This embodiment is similar in most respects to the embodiment of Figure 13 except that the narrowed intermediate portion of the plunger includes as a substitute for a break point a connection whereby the hollow cylindrical portion of the plunger may be unlatched or disconnected from the needle end portion and subsequently re-attached thereto. Such construction allows the hollow finger press portion of the plunger 14b to be used as a needle guard both before and after use, as well as a plunger portion during use. In Figures 13 and 18, the needle end plunger portions are substantially the same except that the narrowed intermediate portion with break point 78 has been replaced with a rectilinear locking mechanism 120 having a rectangular shaped socket 122 with two resilient wings or side arms 124 that are slightly flared in the outward or radial direction. The upper ends of these two arms include lips 126 which are arcuate and have internal grooves 128 which are also arcuate.

The plunger portion 14b as in the embodiment of Figure 13 is a hollow cylindrical cylinder in cross section. However, the needle end portion thereof has been modified as illustrated in Figures 18 and 19 to include a rectilinear portion 130 which is complementary to the rectilinear portion 120. Accordingly, when these portions are joined, both portions 14b and 132 will rotate as a unit. Moreover, since the adapter/plunger engagement structure in this embodiment is the same as that found in the embodiment of Figure 13, for example, unidirectional rotation of the adapter will be obtained in the previously described manner when the plunger is rotated.

Note that the same type of sealing at the finger press end of the syringe comprising complementary ridge arrangements is included in this embodiment. The finger press end of barrel 12b, however, has been tapered to enable arms 124 to flare outwardly and unlock or disengage from the complementary grooves included in plunger portion 14b.

In operation the sterilized syringe is supplied with cylindrical portion 14b connected over the needle and in sealing engagement with the distal end of the barrel 12b. In this regard, although the sealing engagement is illustrated as a threaded connection, other connection means as previously described may be used. As supplied, the syringe would also include the adapter and needle assembly connected to the distal end of the barrel but with the plunger portions 132 and 120 along with bung 136 withdrawn into the barrel and in sealing engagement with the finger press end of the barrel in the same manner noted with regard to the embodiment of Figure 13. Additionally, arms 124 would be positioned as illustrated in Figure 19. (Note, however, that the arms 124 in their unbiased condition may be smaller in diameter than the diameter of the barrel, thus enabling similar attachment of the plunger when the arms 124 lie within the barrel). Accordingly, as supplied, both ends of the syringe would be sealed, thus maintaining sterility as to the enclosed portions of the syringe body. Additionally, once the syringe is used the needle end portion of the plunger along with the adapter and needle assembly may be withdrawn and plunger portion 14b disconnected, as illustrated in Figure 19. Thereafter, the disconnected plunger portion 14b may be reconnected as before to the distal needle end portion of the barrel so that both ends of the syringe are again sealed whereby toxic or contagious material within the syringe body cannot escape. Moreover, in Figure 13, plunger portion 14b may be re-attached to the barrel as a needle guard whether or not the needle assembly has been withdrawn into the barrel.

Thus, single element (14b) may be used both as a needle guard and as a portion of the plunger through the use of the disclosed rectilinear locking mechanism. Moreover, the previously described sealing and locking arrangements and their beneficial results may be maintained. Additionally, the shape and coloration of the elements whereby visibility and accuracy of measurement of the syringe fluid contents may also be applied to the embodiment of Figures 18 through 20. Furthermore, the artisan will appreciate that the beneficial feature of this embodiment may be adapted for use in still other embodiments previously disclosed.

Referring now to the embodiments of the invention illustrated in Figures 21-23, three forms of syringes having tamperproof features are disclosed, respectively. In Figure 21, there is illustrated a syringe having a barrel 300, a finger press 302 for the plunger, and a needle guard 304. The needle guard is, of course, screw-threaded or otherwise secured to the end of the barrel 300, for example, as illustrated in Figures 21 and 22. In this .form of the invention, a strip 306 of paper or other material, such as plastic, having adhesive along one side thereof is applied along a side of the syringe. Particularly, the strip is applied along the side of the barrel 300 and onto the end of the needle guard 304 at its juncture with the barrel 300. The opposite end of the strip 306 is applied to the finger press 302 and preferably extends across the top of the finger press and partially down the opposite side to at least the cylindrical barrel portion. In this manner, the juncture between the finger press 302 and barrel is spanned by at least a portion of the strip 306. As a result, it will be appreciated that any inadvertent or attempted removal of the needle guard from the barrel or rotational or axial movement of the finger press 302 relative to the barrel will cause the strip 306 to tear or become twisted whereby the disruption of the seal at these junctures and possible tampering with the syringe will be indicated.

In Figure 22, another form of tamperproof syringe is disclosed. In the embodiment illustrated in Figure 22, the barrel, finger press and needle guard are indicated as in Figure 21 with the suffix "a" applied thereto. In this form, thin-film plastic material 308 and 310, respectively, is applied, for example, by heat-shrinking, about each of the junctures between the needle guard 304a and barrel 300a on the one hand and the barrel 300a and finger press and plunger portion 302a, on the other hand. Once again, any rotary movement or other movement of the needle guarrt 304a relative to barrel 300a or rotary or axial movement of the finger press 302a relative to barrel 300a will be detected by the severing of the shrink-wrapped plastic material or its wrinkling whereby disruption of the seals at the opposite ends of the syringe or tampering with the syringe will be indicated. It will also be appreciated that the shrink-wrap of plastic material assists in maintaining the sterility of the syringe and that suitable tear strips may be provided along each of the shrink-wrapped portions to facilitate their removal and use of the syringe.

In Figure 23, the like elements of the syringe are illustrated by like reference numerals as in Figures 31 and 22, followed by the suffix "b". In this form, the syringe is dipped into a melted plastic material whereby a thin-film coating of plastic 312 is applied about and completely envelops the syringe with the needle guard attached and plunger located in its axially innermost position. For example, the plastic coat 312 may comprise a clear chlorinated polyvinyl chloride coating (CPCV) . The ingredients are vinyl chloride-vinyl acetate resin silicon dioxide (amorphus) with a methol isobutyl ketone base. This is an air dry coating. The drying can be accelerated by raising the temperature to 100°F. The melting temperature of the plastic material is, of course, less than the melting temperature of the plastic forming the syringe, and it will be appreciated that a clear plastic material should be used such that the gradations and other information on the syringe may be visualized through the thin-film plastic coating. Thus, any efforts to remove the needle guard 304b or displace the plunger will be immediately detectable by the break in the thin-film 12 of plastic material, hence indicating disruption of or tampering with the seals adjacent the opposite ends of the syringe. The coating material is, of course, sufficiently thin to enable the needle guard to be readily removed from the barrel and the plunger to be readily rotated to break the seal, hence permitting axial movement of the plunger relative to the barrel. Therefore, the plastic coating can be left on the syringe barrel during use, eliminating the need to physically strip it from the barrel and dispose of it separately.

Referring now to the embodiments hereof illustrated in Figures 24-26, where relatively small diameter syringes are employed, a different form of adapter and coupling arrangement may be employed. In this form, as illustrated in Figure 24, the end of syringe barrel 400 terminates in an opening having fast-acting threads 402. An adapter 404 is provided and has a hub 406 mounting a needle 408. Adapter 404 has fast-acting male threads 410 for cooperation with the female threads 402. Hub 406 projects from a preferably integral cup-shaped structure having a base 412 and an upstanding annular flange 414. The base 412 is disk-like in configuration for seating against the flange of the barrel end and, in a preferred form, the distal end of flange 414 terminates in a radially inwardly projecting rib 416. The flange 414 may be wholly integral or segmented to provide a flexing action for the segmented flanges, as apparent from the ensuing description.

The interior annular face 418 of adapter 404 includes a plurality of circumferentially spaced, radially extending splines or ratchets 419 which consist, as illustrated in Figure 25, of an angled surface 420 and an axially extending drive surface 422. These splines 418 extend from adjacent the opening through the adapter in communication with the needle to adjacent the flange 414.

The plunger includes a bung 424 and a substantially rigid portion 426 which projects beyond the forward face of bung 424. The forward face of projection 426 has splines or ratchets 428 complementary to and for engaging the splines 418 on the adapter face when the plunger is fully depressed into the barrel. Splines 428 include angled and driving surfaces 420a and 422a. Spaced back from the end of projection 426 containing splines 428 is an annular groove 430 about the periphery of the portion 426. .

In operation, and after an injection has been completed, the plunger is pressed toward the adapter end of the barrel to engage the splines on the respective adapter and projecting portion 426 of the plunger. Upon rotation of the plunger in one direction, drive surfaces 422a on the splines 428 of the plunger will engage driven surfaces 422 on the adapter whereby, because of the arrangement of the cooperating threads 410 and 402, further rotation of the plunger drives the adapter in a direction to unscrew the adapter from the barrel end, enabling the adapter and needle to be withdrawn into the barrel. It will also be appreciated that upon seating the splines 42-8 of the plunger against the splines 419 of the adapter for unscrewing the latter, the groove 430 will be engaged by the projecting rib 416, locking the plunger and the adapter one to the other. Consequently, when the plunger and adapter have been rotated sufficiently to unscrew the adapter from the barrel end, the connective structure of the ribs and recesses enables joint withdrawal of the plunger and adapter so that the adapter and needle may reside wholly within the barrel.

As in the previous embodiments, the end of the barrel is externally threaded. Once the adapter and needle have been withdrawn into the barrel, the plunger may be broken as in Figure 9 and the free portion of the plunger threaded to the end of the barrel whereby the needle will be sealed at both ends of the barrel.

Referring now to Figure 26, the reverse configuration of the connective structure between the plunger and the adapter is illustrated. That is, the flange 414a may have an annular groove 430a adjacent its distal end, while the projecting portion 426a of the plunger may have a radially projecting rib 440. It will be appreciated that upon complete axial insertion of the plunger into the barrel, rib 440 engages in the annular groove 430a to connect the plunger and adapter.

It will also be appreciated that the inside surface of the adapter may be differently shaped than as illustrated. For example, the splines or ratchets may not necessarily extend from the central opening of the adapter but could be spaced radially outwardly therefrom to extend to the radial outer margins of the adapter. Additionally, the base 412 of the adapter may be bowl-shaped, with the splines formed on angled surfaces of the .bowl. Further, the sides of the flanges 414 may be angled radially inwardly toward the end of the barrel and themselves have splines for cooperating engagement with complementary splines formed along the side edges of the projecting portion of the barrel. In this manner, substantial torque may be transferred from the plunger to the adapter. It will also be appreciated that the integral needle and hub connection illustrated in Figures 24-26 may comprise, as in the prior embodiments, a Luer lock type connection between the hub 406 and the needle 408 and that conversely the Luer lock type connections described and illustrated with respect to the previous embodiments may be replaced by an integral connection between the adapter and needle.

As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope there¬ of. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.

Claims

WHAT IS CLAIMED IS:

1. A syringe comprising:

(a) a hollow axially-elongated barrel for containing fluid to be injected by the syringe;

(b) an adapter removably mounted at the distal end of said barrel, having a portion projecting into the barrel toward its proximal end and having a fluid passage in communication with the interior of the barrel;

(c) a ferrule carrying a hollow needle and adapted for removable connection with one of the distal barrel end and the adapter adjacent the barrel end, with the hollow needle in communication with the fluid passage of the adapter;

(d) a plunger axially movable in the hollow barrel; and

(e) an adapter engagement structure disposed at the distal end of the plunger and engageable with a mating connection engagement structure on the projecting adapter portion in response to axial movement of the plunger toward the distal end of the barrel, said structures being cooperable to cause (1) relative rotation of the plunger end and the adapter in response to such axial movement, and (2) the adapter and needle ferrule with the needle attached thereto to part from the end of the barrel in response to subsequent relative rotation of the plunger and the barrel, thereby enabling the adapter and the needle ferrule with the needle attached thereto to be withdrawn into the interior of the barrel when the plunger is withdrawn from the distal end of the barrel;

(f) said fluid passage of said adapter having a passage portion opening into said barrel at a location between the proximal end of said projecting adapter portion and the distal end of said barrel to enable air to be vented from said barrel through said needle upon receiving fluid into said barrel and moving said plunger toward the distal end of said barrel.

2. A syringe as in Claim 1 wherein the needle ferrule is removably coupled to the adapter with a threaded connection.

3. A syringe as in Claim 2 wherein the engagement structures on the adapter and at the distal end of the plunger -include mating ramps connections.

4. A syringe as in Claim 1 wherein the adapter is detachably connected to the distal end of the barrel by a threaded connection of a first sense while the engagement structures between the adapter and plunger include a threaded connection of a second sense, opposite said first sense, said fluid passage portion opening forming the most superior portion of the hollow barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

5. A syringe as in Claim 1 wherein said fluid passage extends centrally through said adapter between and through proximal and distal ends thereof and said fluid passage portion extends substantially laterally between said proximal and distal ends and in communication with said central fluid passage, said fluid passage portion opening forming the most superior portion of the hollow barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

6. A syringe according to Claim 1 wherein said fluid passage extends centrally through at least a portion of said adapter terminating short of the proximal end thereof, said fluid passage portion extending substantially laterally between said proximal and distal ends and in communication with said central fluid passage, said fluid passage portion opening forming the most superior portion of the hollow barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

7. A syringe as in Claim 1 wherein the' needle ferrule is releasably engaged with the distal end of the adapter, and the engagement means at the proximal end of the adapter engages with the plunger in response to rotation of the plunger end, said fluid passage extending axially through the adapter and opening through the proximal and distal ends thereof.

8. A syringe as in Claim 1 wherein the needle ferrule is releasably engaged with the distal end of the adapter, and the engagement means at the proximal end of the adapter engages with the plunger in response to rotation of the plunger end, said fluid passage extending axially through the adapter and terminating short of the proximal end of said adapter.

9. A syringe as in Claim 7 wherein the adapter is releasably connected to the end of the barrel by a female-male thread combination, the adapter having a spiral thread and drive surfaces, the plunger end having driving surfaces for engaging the drive surfaces on the adapter in response to relative rotation of the plunger end and the adapter and along said thread to align and engage the driving and drive surfaces of the plunger end and adapter, respectively, and thereafter for rotating the adapter relative to the barrel to enable axial withdrawal of the adapter and needle ferrule along the barrel, said fluid passage comprising a central passage, a second fluid passage portion in communication with said central passage and opening into said barrel^* at a location between its proximal and distal ends and circu ferentially spaced about said adapter from the first mentioned fluid passage portion.

10. A syringe as in Claim 9 wherein the needle ferrule includes a female Luer lock fitting, which is engaged with the adapter with a plain Luer tip or Luer lock male fitting.

11. A syringe as in Claim 7 wherein the adapter is threadedly couplable to the barrel and to the plunger with respectively opposite thread directions.

12. A syringe as in Claim 1 wherein the adapter is detachably connected to the distal end of the barrel by a threaded connection of a first sense while the engagement structures between the adapter and plunger include a threaded connection of the same sense as said first sense.

13. A syringe as in Claim 1 wherein the needle ferrule is releasably engaged with the barrel end, the adapter being releasably connected to the end of the barrel by a female-male thread combination, the adapter having a spiral thread and drive surfaces, the plunger end having driving surfaces for engaging the drive surfaces of the adapter in response to relative rotation of the plunger end and the adapter and along said spiral thread and thereafter for rotating the adapter relative to the barrel to enable axial withdrawal of the adapter and needle ferrule along the barrel.

14. A syringe as in Claim 1 including connection structure at the distal end of said barrel and complementary connection structure at the end of said plunger opposite its distal end, said plunger having structure intermediate its ends for detachably connecting the distal and opposite ends of the plunger whereby the opposite end of the plunger can be detached from the plunger and connected to the distal end of the barrel when the plunger has been withdrawn from the distal end of the barrel.

15. A syringe as in Claim 1 including a seal structure on the inside surface of the barrel adjacent its proximal end and a mating seal structure on the outside surface of said opposite plunger end, a needle guard releasably and sealingly connected adjacent the distal end of the barrel whereby the seal provided by the needle guard and seal structure at the respective distal and opposite ends of the barrel is sufficient to maintain sterile conditions within the syringe between the seals until the syringe is used.

16. A hollow adapter for the interior of a syringe having a barrel, and a piston axially movable within the barrel, said adapter releasably attaching a hollow needle base to the distal end of the syringe and comprising:

(a) a fitting formed at the distal end of the adapter for releasably coupling to the base of the syringe needle;

(b) a releasable engagement means formed on the exterior of the adapter for releasable engagement with the interior of the distal end of the syringe barrel;

(c) an engagement means formed in a proximal end portion of the adapter for engagement with the distal end of the plunger including a non-jamming spiral thread one revolution or less about an axis coincident with the barrel axis and a groove formed about the adapter at an axial location adjacent the base of the thread; and

(d) means defining a fluid passage through said adapter including a central passage portion and a portion in communication therewith opening laterally of said adapter at a location between its proximal and distal ends.

17. An adapter according to Claim 16 wherein the releasable engagement means includes a male thread.

18. A syringe having a plunger axially movable within a barrel toward and away from a distal end of the barrel carrying a needle and a multiple engagement mechanism disposed at said distal end, said mechanism including first, second and third separate attachment areas for effecting selective individually controllable attachment respectively: (a) to said distal end of the barrel, (b) to the distal end of said plunger and (c) to a removable hollow needle base, wherein said second attachment area includes a hollow central protrusion having a proximal end and at least one helical track around an outer surface of the protrusion, said mechanism having an axial fluid passage in communication with said needle and at least a portion of said passage opening adjacent said protrusion and spaced from said proximal end thereof.

19. A syringe as in Claim 18 wherein said second attachment area further includes at least one snap-engagement groove disposed on the outer surface of said protrusion at a location axially spaced from said at least one helical track.

20. A syringe as in Claim 18 wherein said fluid passage portion opens at a location laterally offset from the axis of said fluid passage, a second fluid passage portion in communication with said axial passage and opening adjacent said protrusion, spaced from said proximal end thereof and circumferentially spaced from the first mentioned fluid portion, one of said first and second fluid passage portion openings forming the most superior portion of the barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

21. A syringe as in Claim 18 including connection structure at the distal end of said barrel and complementary connection structure at the end of said plunger opposite its distal end, said plunger having structure intermediate its ends for detachably connecting the distal and opposite ends of the plunger whereby the opposite end of the plunger can be detached from the plunger and connected to the distal end of the barrel when the plunger has been withdrawn from the distal end of the barrel.

22. A syringe as in Claim 18 including a seal structure on the inside surface of the barrel adjacent its proximal end and a mating seal structure on the outside surface of said opposite plunger end, a needle guard releasably and sealingly connected adjacent the distal end of the barrel whereby the seal provided by the needle guard and seal structure at the respective distal and opposite ends of the barrel is sufficient to maintain sterile conditions within the syringe between the seals until the syringe is used.

23. A syringe as in Claim 20 wherein said second attachment area includes a pair^* of said helical tracks and a pair of said snap engagements, the members of each said pair being spaced apart approximately 180° circumferentially.

24. A device for use with a syringe barrel and piston and a removable hollow syringe needle, said device comprising:

a central body having a bore for transmitting fluid through said body, a distal portion tapered to mate inside a standard hollow needle base and a proximal portion with engagement surfaces for receiving the distal end of a syringe piston latch;

a radially projecting portion extending circumferentially and radially outwardly from said central body and disposed between said distal and proximal portions, said radially projecting portion being sized to fit within the distal end of a syringe barrel, said engagement surfaces of the central body including a pair of ramps disposed along the outside of said central body and terminating in linear axially and radially extending surfaces for engaging corresponding surfaces on .the distal end of the syringe piston latch; and an externally threaded section on said adapter sized to removably mate within an internally threaded portion of the distal end of a syringe barrel;

said central body bore having a passage portion in communication therewith and opening between said radially projecting portion and the end of said proximal portion.

25. A device as in Claim 24 wherein said adapter has a latching surface including at least one groove for engaging a projection carried by the syringe piston latch.

26. A device as in Claim 24 wherein said cylinder section includes an internal Luer lock thread surrounding the tapered distal portion of the central body.

27. A device as in Claim 24 wherein said radial projecting portion includes a flared outer rim to matingly seal against a flared portion of the distal end of a syringe barrel.

28. A device as in Claim 24 wherein said radially projecting portion has a generally annular face facing the proximal portion of said central body and tapered radially inwardly toward the distal portion of said central body.

29. A syringe comprising:

(a) a hollow, axi lly-elongated barrel;

(b) an adapter carried by said barrel adjacent the distal end thereof and removable therefrom in response to rotation relative to the barrel, the adapter having a fluid passage in communication with a hollow needle;

(c) a plunger axially movable in the hollow barrel; and

(d) adapter engagement structure disposed at the distal end of the plunger and engageable with a mating connection engagement structure on the adapter and projecting into the interior of said hollow barrel, said structures having alignment, drive and connective pairs of respective engagement surfaces, said alignment pair of surfaces being engageable and relatively movable to align and engage said drive surfaces one with the other thereby to enable subsequent rotation of the adapter relative to the barrel in response to relative rotation of the plunger and barrel, said connective surfaces being engageable in response to -substantially full axial insertion of said plunger in said barrel to connect the plunger and adapter one with the other, enabling the adapter and any attached needle to part from the end of the barrel and to be withdrawn into the interior of the barrel when the plunger is withdrawn from the distal end of the barrel;

said fluid passage having at least a portion thereof opening through said adapter into the interior portion of said barrel at a location between its opposite ends such that said fluid passage portion opening forms the most superior portion of the interior of said barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

30. A syringe according to Claim 29 wherein said alignment pair of surfaces are relatively rotatable in response to axial movement of said plunger in said barrel and in a direction toward full axial insertion of the plunger in the barrel.

31. A syringe according to Claim 29 wherein said connective surfaces comprise a groove on one of said adapter and said plunger and a projection on the other of said adapter and said plunger for reception in said groove.

32. A syringe according to Claim 29 wherein said drive surfaces comprise a radially and axially extending flat on each of said adapter and said plunger.

33. A syringe according to Claim 29 including male screw threads carried by said distal end of said barrel, female threads carried by the proximal end of the plunger, said plunger having a weakened section intermediate its ends for breaking off a portion of the plunger, including the proximal end, upon withdrawal of the plunger from the distal end of the barrel whereby the broken-off portion may be threaded to the barrel by the cooperable male and female threads on the barrel and plunger end, respectively.

34. A syringe according to Claim 29 wherein said plunger has a weakened section intermediate the ends for breaking off a portion of the plunger including its proximal end upon withdrawal of the plunger from the distal end of the barrel, means on said barrel and plunger cooperable to prevent withdrawal of the plunger totally from within said barrel, said weakened portion lying outside the barrel upon withdrawal of the plunger to its fullest extent from the barrel.

35. A syringe according to Claim 29 including connection structure at the distal end of said barrel and complementary connection structure at the end of said plunger opposite its .distal end, said plunger having structure intermediate its ends for detachably connecting the distal and opposite ends of the plunger whereby the opposite end of the.,plunger can be detached from the plunger and connected to the distal end of the barrel when the plunger has been withdrawn from the distal end of the barrel.

36. A syringe as in Claim 29 including a seal structure on the inside surface of the barrel adjacent its proximal end and a mating seal structure on the outside surface of said opposite plunger end, a needle guard releasably and sealingly connected adjacent the distal end of the barrel whereby the seal provided by the needle guard and seal structure at the respective distal and opposite ends of the barrel is sufficient to maintain sterile conditions within the syringe between the seals until the syringe is used.

37. A syringe as in Claim 29 wherein said alignment pair of surfaces being engageable to back said plunger away from said adapter in response to rotation of said plunger relative to said barrel in a direction opposite to said relative rotation of said plunger and said barrel.

38. A syringe comprising:

(a) a hollow, axially-elongated barrel;

(b) an adapter carried by said barrel adjacent the distal end thereof and removable therefrom in response to rotation relative to the barrel, the adapter having a central fluid passage and adapted for removable coupling to a hollow needle;

(c) a plunger axially movable in the hollow barrel;

(d) cooperable rotary drive and driven surfaces on said plunger and said adapter, respectively;

(e) connective surfaces on said plunger and adapter, respectively;

(f) means cooperable between the distal end of the plunger and the adapter to enable initial relative rotation therebetween in response to axial movement of the plunger in the barrel toward full insertion to (a) align the cooperable rotary drive and driven surfaces, respectively, one with the other and (b) engage the connective surfaces thereof enabling joint axial movement of the adapter and plunger and, (c), upon subsequent relative rotational movement of said plunger and barrel, enable said adapter to part from the end of the barrel and to be withdrawn into the interior of the barrel when the plunger is withdrawn from he distal end of the barrel;

(g) said adapter having an axial portion projecting into the barrel defining therewith an annular space therebetween, said central fluid passage having a lateral portion opening through said adapter into said annular space at a location such that said fluid passage portion opening forms the most superior portion of the interior of said barrel when the syringe is held in a generally vertical orientation with the needle uppermost.

39. A syringe comprising:

(b) an adapter removably mounted at the distal end of said barrel and having a fluid passage in communication with the interior of the barrel;

(d) a needle guard releasably connected with one of said ferrule and said distal barrel end;

(e) a plunger axially movable in the hollow barrel between retracted and extended positions relative to said barrel; and (f) means connecting between said barrel and said needle guard and between said barrel and said plunger in the retracted position of said plunger to indicate attempted removal of said needle guard from said one of said ferrule and said distal barrel end and movement of said plunger relative to said barrel from said plunger retracted position.

-40. A syringe according to Claim 39 wherein said connecting means includes a tape secured to said barrel and extending to overlie portions of said needle guard and said plunger.

41. A syringe according to Claim 39 wherein said connecting means includes a first plastic material heat-shrunk about said needle guard and said one of said ferrule and said distal barrel end and a second plastic material heat-shrunk about said barrel and exposed portions of said plunger in said retracted position thereof.

42. A syringe according to Claim 39 wherein said connecting means includes a thin film coating of plastic material on the exposed external surfaces of said needle guard, said barrel and said plunger.

55

43. A syringe comprising:

(a) a hollow, axially-elongated barrel;

(b) an adapter carried by said barrel adjacent the distal end thereof and removable therefrom in response to rotation relative to the barrel, the adapter having a central fluid passage and having a hollow needle coupled thereto;

(c) a plunger axially movable in the hollow barrel; (d) cooperable rotary drive and driven surfaces on said plunger and said adapter, respectively;

(e) connective surfaces on said plunger and adapter, respectively;

(f) means cooperable between the distal end of the plunger and the adapter to enable initial relative rotation therebetween in response to axial movement of the plunger in the barrel toward full insertion to (i) align the cooperable rotary drive and driven surfaces, respect¬ ively, one with the other and (ii) engage the connective surfaces thereof enabling joint axial movement of the adapter and plunger and, (iii) , upon subsequent relative rotational movement of said plunger and barrel, enable said adapter to part from the end of the barrel and to be with¬ drawn into the interior of the barrel when the plunger is withdrawn from the distal end of the barrel;

(g) said adapter having an annular portion projecting into the barrel defining a central recess for receiving said rotary drive surfaces and the connective surfaces of said plunger.