Abstract:
A syringe tip for a syringe and the like in which the bore of the tip tapers so as to increase in diameter from the end of the tip adjacent the barrel of a syringe towards the distal end of the tip; and the outside diameter of said tip tapers so as to decrease in diameter from the proximal end of the tip (adjacent the barrel of said syringe) towards the distal end of the tip.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to GB 1117434.9 filed Oct. 10, 2011 which is incorporated herein by specific reference. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to syringes, and particular to connection systems for syringes, and especially for enteral syringes. 
       BACKGROUND AND PRIOR ART KNOWN TO THE APPLICANT 
       [0003]    For many years, a 6% taper has been used on medical connectors to connect syringes with needles and other fluid-transporting devices such as intravenous catheters, valves and filters. This 6% taper is commonly described as a “Luer” connection, named after the century German medical instrument maker Hermann Wülfing Luer, the 6% taper having previously been used successfully for tapered glass stoppers for bottles. A typical Luer connection uses an externally-tapered male connection for syringes, and a corresponding 6% internal taper for needles. The Luer standard (and its specification is enshrined in international standard ISO 594:1986 “Conical fittings with a 6% (Luer) taper for syringes, needles and certain other medical equipment”) has been so successful that it became the connection of choice for all kinds of delivery systems including enteral, intravenous and intrathecal. 
         [0004]    However, it became apparent that this standard allowed inadvertent misconnection of drug-filled syringes and other fluid-containing devices causing misadministration of medicaments into the wrong part of the body, sometimes with fatal consequences. 
         [0005]    One reaction to this has been the development of separate “standards” for enteral connectors—i.e., for connectors destined to be used on syringes, tubes and other medical devices to deliver drugs, nutritional formulations and other fluids into the gastrointestinal tract. 
         [0006]    One such system, described in U.S. Patent Application U.S. 2007/0076401 in the name of Vygon, typically uses a 5% taper connection. In the Vygon system, syringes are usually provided with female (internal) tapered connections (as opposed to the male 6% taper in the Luer system); a smaller diameter than the standard Luer diameter is also typically used. 
         [0007]    In another system, sold by Fresenius Kabi, a larger 2% taper connection is used, with syringes being provided with an external taper—i.e., a “male” fitting. 
         [0008]    In yet further systems, a so-called “catheter tip connector” is used, having a yet larger tapered connection, but again using an external taper—a “male” fitting—on syringe elements. 
         [0009]    Whilst these systems have been successful in preventing misadministration of enteral formulations by other routes (and vice-versa), the presence of different enteral systems can cause problems in health-care settings where more than one of the different enteral standards are used. This can occur even in the same hospital where, for example, one system might be used on a paediatric ward, and another system on general wards. This can lead to situations where a patient is transferred from one ward to another, and appropriately-connecting syringes are unavailable to connect with medical devices already attached to a patient. 
         [0010]    It is amongst the objects of the present invention to attempt a solution to this and other problems. 
         [0011]    At the time of writing, the applicant acknowledges the following prior art documents: 
         [0000]    WO2009/144583A1 BECTON, WO2010/14019A1 BECTON, U.S. Pat. No. 5,609,584A GETTIG, U.S. Pat. No. 4,596,561A MEYER, and WO8805668A1 MEYER. 
       SUMMARY OF THE INVENTION 
       [0012]    Accordingly, the invention provides a syringe tip for a syringe and the like in which the bore of said tip tapers so as to increase in diameter from the proximal end of the tip (adjacent the barrel of said syringe) towards the distal end of the tip; and the outside diameter of said tip tapers so as to decrease in diameter from the proximal end of the tip (adjacent the barrel of said syringe) towards the distal end of the tip. 
         [0013]    Preferably, a syringe tip for a syringe and the like where the syringe tip extends from the barrel of a syringe; said syringe tip comprises an internal bore and an outside diameter; said internal bore incorporating a taper at the distal most portion of the tip; said taper continuously increasing in diameter from the proximal end of the tip which is adjacent the barrel of the syringe towards the distal end of the tip; whereby said taper facilitates a liquid-tight connection to any appropriately mating connector; and the outside diameter of the tip tapers so as to decrease in diameter in the distal most portion of the tip towards the distal end of the tip; whereby said taper facilitates a liquid tight connection to any appropriately mating connector. 
         [0014]    Preferably the external taper of said tip is not 6%. 
         [0015]    Preferably also, the taper of the bore of said tip is not 6%. 
         [0016]    In either case, it is preferable that the external taper of said tip is between 1% and 4%. 
         [0017]    It is also preferable that the taper of the bore of said tip is less than 6%, and preferably between 3% and 5.5%. 
         [0018]    In any aspect of the invention the syringe tip further comprises an externally-projecting locking portion on the outside of said tip. 
         [0019]    In a further aspect, the invention provides a syringe wherein a portion of the outside surface of the syringe barrel adjacent the syringe tip is tapered, having an outside diameter that decreases towards the syringe tip, thereby being capable of forming a fluid-tight connection with a correspondingly internally tapered connector. 
         [0020]    Preferably said tapered portion of the barrel is graduated. 
         [0021]    More preferably said syringe further comprises a syringe tip as described above. 
         [0022]    Also included within the scope of the invention is a syringe tip or a syringe substantially as described herein with reference to any appropriate combination of the accompanying drawings. 
         [0023]    Also included within the scope of the invention is a syringe comprising a syringe barrel and a syringe tip as described herein. 
         [0024]    In a further independent aspect, the invention provides a syringe tip and connector assembly comprising, a syringe tip for a syringe and the like where the syringe tip extends from the barrel of a syringe; said syringe tip comprising an internal bore and an outside diameter; said internal bore incorporating a taper at the distal most portion of the tip; said taper continuously increasing in diameter from the proximal end of the tip which is adjacent the barrel of the syringe towards the distal end of the tip; and the outside diameter of the tip tapers so as to decrease in diameter in the distal most portion of the tip towards the distal end of the tip; and a connector body with at least one of an outer diameter to facilitate a liquid-tight connection with said internal bore of said syringe tip; and an inner diameter configured to facilitate a liquid-tight connection with said external diameter of said syringe tip. 
         [0025]    In a subsidiary aspect, the connector body comprises an outer diameter and an inner diameter both configured to facilitate a liquid-tight connection with both said outside diameter and said internal bore of said tip. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    The invention will be described with reference to the accompanying drawings, in which: 
           [0027]      FIGS. 1 and 2  are cross-sections of syringe tips of the invention; 
           [0028]      FIG. 3  is a perspective view of a syringe tip and syringe of the invention; 
           [0029]      FIG. 4  is a cut-away perspective view of a syringe tip and syringe of the invention; 
           [0030]      FIG. 5  is a perspective view of a syringe of the invention; and 
           [0031]      FIG. 6  is a cut-away perspective view of a syringe of the invention. 
           [0032]      FIGS. 7 ,  8  and  9  are cross-sections of assemblies of the invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0033]      FIGS. 1 and 2  show, in cross-sectional view, a syringe tip, generally indicated by  1 , according to the invention. In this tip, the bore  2  of the tip  1  is tapered, such that the internal diameter of the bore adjacent the discharge end of the tip  3  is larger than the internal diameter at the end of the tip  4  adjacent the barrel of the syringe. The internal taper, indicated by angle A in  FIG. 2 , is arranged to be at an angle that is incompatible with a male Luer connector, i.e. it is not a 6% taper. Preferably, the taper is configured to be less than 6%. The taper is preferably between 3% and 5.5%. This prevents interconnectivity with Luer fittings destined for use with medicaments not intended to be delivered enterally, and vice-versa. Most preferably, a 5% internal taper is used. In this way, the internal bore of the syringe tip will fluidly mate with a Vygon connector as described above. 
         [0034]    The external surface  5  of the syringe tip  1  is also provided with a taper such that the external diameter of syringe tip at the discharge end is smaller than the diameter at the end of the tip adjacent a syringe barrel. The external taper, indicated by B in  FIG. 2 , is again configured not to fluidly mate with a Luer connector, i.e., it is not a 6% taper. In preferred embodiments, the external taper B is between 1% and 4%, and preferably the taper is 2%. A 2% taper is equivalent to a taper of 3.43° (i.e., 1.74° for each side). In this way, the external surface will mate with Fresenius fittings as described above. 
         [0035]    Whilst it is especially and preferably envisaged that such syringe tips will form part of a syringe, it is also envisaged that the tips could be used as a general connector for enteral lines, for example as part of enteral “giving sets”, being fluidly-connected e.g., to the end of a tube. In this case, references to “adjacent the syringe barrel” and like terms may be construed as “adjacent the tube”, and most generally meaning upstream of the fluid connection. 
         [0036]    At  FIG. 1  it can clearly be seen that the bore  2  of the tip  1  comprises a continuous taper from end  24  inwards. This allows for a continuous, single, uninterrupted contact between the bore  3  and a suitably disposed connector. This contact forms an internal fluid tight (water tight) attachment between a connector and the tip of the syringe. The external surface  5  of the syringe tip  1  comprises a continuous taper  20  along the majority of its length for a similar continuous, uninterrupted contact with a suitably disposed connector (not shown). This contact facilitates an external fluid tight attachment between a connector and the external surface of the syringe tip. However, in this preferred embodiment there is also shown a step  21  which splits the taper of the external surface into a first side  22  and a second side  23 —thus along the whole of its length the taper of the external surface  5  of the syringe tip  1  is discontinuous although it is the case that each of first side  22  and second side  23  is linear (like the taper of bore  3 ) in its taper. Indeed in particularly preferred embodiments, the taper of the first side  22  and the taper of the second side  23  run along notionally parallel linear paths, sharing as they do the same angle. In other words, the first portion of the tip both externally and internally, starting from the distal most extremity  24  of the syringe tip comprises a continuous taper which facilitates in a first mode of use an external liquid tight attachment to a connector and in a second mode of use an internal liquid tight attachment to a connector. 
         [0037]    Whilst the syringe tip  1  as illustrated comprises an end  24  wherein the end comprises a squared off outer edge  25  and a squared off inner edge  26 , in an alternative embodiment the edges of the distal or discharge end  3  of the tip may be rounded or chamfered. 
         [0038]      FIG. 3  illustrates, in perspective view, a further syringe tip, generally indicated by  1 , forming part of a syringe, generally indicated by  6 . In this embodiment, the syringe tip  1  has a first externally tapered portion  7  at the end distal from the syringe barrel  8 . The configuration of this portion is as described above for the syringe tip of  FIGS. 1 and 2 . The bore of this syringe tip portion  7  is also internally tapered, again as described above for the syringe tip of  FIGS. 1 and 2 . 
         [0039]    The syringe tip also has a second externally tapered portion  9  located adjacent the syringe barrel  8 . This second tapered portion  9  has a taper such that the external diameter of the portion decreases in a direction away from the end proximal to the barrel  8  and towards the discharge end of the tip  1 . The taper in this portion is configured to be that of a catheter taper, i.e., preferably a taper of 2°. 
         [0040]    In this embodiment, outwardly-projecting lugs  10  are provided between the two externally tapered portions  7  and  9 . The lugs are preferably configured to form part of a helix. The lugs may be used to lock the end of the syringe tip to a connector having a corresponding internal thread arrangement, such as is found in the Vygon connector described above. 
         [0041]      FIG. 4  illustrates in cut-away perspective view, the syringe tip and syringe of  FIG. 3 . The cutaway view illustrates that the internal bore  2  of the first tapered portion  7  is also tapered, as described for the tip illustrated in  FIGS. 1 and 2 . 
         [0042]      FIG. 5  illustrates a further embodiment of an aspect of the invention in perspective view. This embodiment comprises a syringe, generally indicated by  11  in which a portion  12  of the external surface of the syringe barrel  8  is provided with a taper, in which the outside diameter of the barrel  8  decreases towards the discharge end of the syringe. Preferably the taper is 2°, such that it can function as a catheter tip connector. 
         [0043]    At the end of the syringe is a syringe tip  13 . In preferred embodiments, this tip is provided with an external, and preferably an internal taper, as described for the embodiment of  FIGS. 1 and 2 . 
         [0044]    The external body of the barrel  8  is also marked with graduations  14  to indicate volume. This configuration of syringe is particularly suited to small volume syringes, and particularly those having a volume of about 1 ml. 
         [0045]      FIG. 6  shows the syringe of  FIG. 5  in cross-sectional view, also including a plunger  15 , slideably sealed within the barrel  8  of the syringe  11 . It can be seen that the sealing end of the plunger  16  extends into the portion of the barrel  12  that is tapered, i.e. it extends completely into the connector portion. In this way, dead space in the connector is effectively eliminated. 
         [0046]    At  FIG. 7 , an assembly  50  is shown. The assembly comprises a syringe tip  52  and a connector  54 . The syringe tip  52  comprises an internal bore  56  with the taper of the type described in the foregoing paragraphs. The syringe tip also comprises an outer diameter  58  with a taper also so described in the foregoing paragraphs. The taper of the internal bore  56  comprises a first syringe tip contact surface  60 , whilst the outer diameter  58  comprises a second syringe tip contact surface  62 . In this assembly, the connector  54  is so sized that the forward most portion of the syringe tip  52  fits inside it thereby forming a liquid tight (e.g., water tight) connection. The connector  54  comprises a tube  64  with a taper which decreases in diameter from its distal extremity inwards. The syringe  52  and the connector  54  are shown mated with one another and as such the taper on the inner diameter  66  of the tube which comprises a first tube contact surface is at a complementary angle to that of the outer diameter  58  of the syringe tip  52 , mating with it and forming a continuous, linear, uninterrupted, liquid tight connection. 
         [0047]    At  FIG. 8 , a second assembly  70  is shown—whilst syringe tip  52  remains essentially the same, the connector  72  here fits inside the bore  56  of the syringe tip  52 . The connector  72  comprising a tube  74  and having an outer diameter  76  which itself has a taper, the taper decreasing the outer diameter  76  of the tube  74  prior to the termination of the tube  74  at its tip. The taper of the outer diameter  76  of the tube  74  matches the taper of the bore  56  of the syringe tip  52 . The taper of the outer diameter  76 , the tube  74  defines a second tube contact surface  78  which mates with and forms a continuous, linear, uninterrupted liquid tight connection with first syringe tip contact surface  84 . 
         [0048]    At  FIG. 9 , a third assembly  90  is shown, wherein the syringe tip  52  comprises an inner bore with a taper comprising a first syringe tip contact surface  94  and an outer diameter  96 , comprising a second syringe contact surface  98 . The syringe tip mates with connector  100  comprising a bifurcated tube  102  which fits on both the inside and outside of syringe tip  92 , having a first tube contact surface  104  and a second tube contact surface  106 , each of those contact surfaces  104 ,  106  having a taper corresponding to the mating contact surfaces  60 ,  62  of the syringe tip. In this configuration, there is provided a succession of an internal fluid tight connection and an external fluid tight connection. 
         [0049]    In a preferred embodiment of any of the  FIGS. 1-9 , the Syringe tip  1  may be an integrally formed part of the syringe  6 .