Abstract:
An assembly comprising a flanged flask and a syringe device fixable thereto is provided. The syringe device includes a guide member for cooperating with the body of the flask. The guide member includes a first end with an internal guide surface at its terminal portion and a fastening mechanism set back from the internal guide surface. The internal guide surface cooperates with the cylindrical body of the flask and the fastening mechanism attached to the flange of the flask. A second end of the guide member provides translational guidance to a syringe.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a syringe device fixable on a flask, in particular a flask containing a liquid to be injected or a substance that has been lyophilized and that is to be mixed with a physiological liquid or with medication so that the mixture can be injected. 
     2. Description of Related Art 
     There exist known substances, particularly in the medical field, which need to be stored separately and which should be mixed only immediately prior to being injected into a patient, e.g. subcutaneously, intravenously, or into muscle. This applies in particular to medical substances which are prepared in lyophilized (freeze dried) form, or in powder form, and which need to be mixed with a solvent, e.g. physiological serum, for administration to a patient. In other cases, the two components that are mixed together may both be liquids, when the liquids cannot be stored for long periods of time when mixed together. 
     The most commonly used technique is to store the powder in a separate receptacle which is closed by a membrane or a leakproof plug that can be punctured by means of a needle. Then, using a syringe of standard type, a certain quantity of solvent is taken from a second receptacle and the appropriate quantity of solvent is injected into the first receptacle through the membrane. The content of the first receptacle is then mixed together and the same syringe is then used to suck up the mixture. The syringe is then ready for injecting the medication. 
     In other known techniques, the liquid, e.g. physiological serum, is already contained in the syringe. It then suffices to inject the liquid through the puncturable membrane into the receptacle containing the substance in powder form, to mix the substances together, and then suck the mixture back into the syringe. 
     However, that technique suffers from certain difficulties in use. In particular, when the flask containing the powder has a neck of small diameter, it is difficult to puncture the puncturable plug appropriately. An essential condition for extracting all of the liquid contained in the flask after the powder has been mixed with the solvent is for the puncturable plug to be punctured in its center and for the needle to be inserted as small a distance as possible into the flask. That also serves to avoid wetting the needle while mixing is being performed, thus leaving the needle in a condition suitable for being reused to inject the mixture into the patient. Unfortunately, as already mentioned, when the neck of the flask is of small diameter, this can be difficult to do. There also exists a non-negligible risk of the user, e.g. a nurse, pricking a finger while performing the above operation. 
     An object of the present invention is to provide a syringe device that is fixable on a flask and which ensures that the puncturable plug is punctured in its center and which also makes this operation very reliable and completely repeatable. Another object of the present invention is to provide such a device which can be fitted onto a flask commonly used for containing medicinal powders for mixing with a solvent, and in particular substances that have been lyophilized. 
     SUMMARY OF THE INVENTION 
     According to the invention, this object is achieved by a syringe device suitable for fixing on a flask that has a cylindrical body, an opening surrounded by a flange presenting a side face, and a puncturable plug closing said opening, the device being characterized in that it comprises a guide part suitable for co-operating with said flask, and a syringe provided with a needle and mounted to slide in said guide part, said guide part including an open first end having at its terminal portion a first internal guide surface suitable for co-operating with the cylindrical body of said flask, and fastening means for fastening said part to said flange, which means are set back relative to said first internal guide surface, said fastening means being activated while said device is being put into place on said flask, said guide part including a second end and a common portion suitable for receiving said syringe provided with means for providing guidance in translation to said syringe in said guide part in order to bring said syringe into an engaged position in which its needle punctures the puncturable membrane of the flask, said guide part also having a central orifice for allowing the end of said needle to pass through under the effect of said syringe moving in translation. 
     It will be understood that in this way, because of the presence of the guide surface at the end of the guide part co-operating with the cylindrical body of the flask over sufficient length, the guide part is accurately centered relative to the puncturable plug of the flask. Consequently, the end of the needle of the syringe is properly positioned facing the central portion of the puncturable plug of the flask, thereby enabling the plug to be punctured under optimum conditions when the syringe is pushed into the guide part. Also, since the syringe is guided in translation relative to the guide part, this ensures that the positioning of the needle relative to the plug is maintained while the syringe is moving. In addition, the presence of the fastening elements makes it possible to secure the guide part, and thus the syringe, to the flask, thus making it easier to maneuver the syringe relative to the flask. In particular, that makes it possible to monitor very accurately how far the syringe has been pushed into the guide part, and thus how far the tip of the needle has penetrated into the flask after the plug has been punctured, in order to ensure that such penetration is kept down to a minimum. Naturally, after the operation of mixing and then sucking the mixture back into the syringe, the syringe can be separated from the guide part. 
     Preferably, the first end of the guide part includes a second internal guide surface suitable for co-operating with the side wall of the flange of the flask, the fastening means being disposed between the first and second guide surfaces. The presence of these two guide surfaces makes it possible to reduce the length of the first guide surface while obtaining accurate centering of the guide part relative to the flask. 
     Also preferably, in a first embodiment, the means for guiding the syringe in translation in the guide part include sealing means for providing sealing between the inside face of the guide part and the body of said syringe. 
     In a second embodiment, the means for guiding the syringe in the guide part include at least one guide face formed in the inside face of the guide part and suitable for co-operating with a portion of the body of said syringe. 
     According to another characteristic of the invention, the guide part includes a plate element disposed substantially perpendicularly to the direction of displacement of the syringe and in which the central orifice is formed, the face of the plate directed towards the first end of the guide part being provided with a projecting annular rib surrounding the central orifice, whereby said rib is pressed against the plug of said flask while said fixing means co-operate with said flask. 
     Other characteristics and advantages of the present invention appear more clearly on reading the following description of various embodiments of the invention given as non-limiting examples. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description refers to the accompanying drawings, in which: 
     FIG. 1 is a vertical section through a flask usable with the syringe device of the invention; 
     FIG. 2 is a section through a first embodiment of the syringe device; 
     FIG. 2A illustrates a removable cap for use with a syringe device according to the invention 
     FIG. 3 is a perspective view of the syringe device fixed on a flask; 
     FIG. 4 a  is a detail view of FIG. 2 showing how the syringe device is fixed on a flask; 
     FIG. 4 b  is a horizontal section view on line B—B of FIG. 4 a;    
     FIG. 5 is a view partially in perspective and partially in vertical section, showing a second embodiment of the syringe device fixed on a flask; 
     FIGS. 6 a  to  6   c  show how the syringe device is used; and 
     FIG. 7 is a fragmentary vertical section through a third embodiment of the syringe device. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference initially to FIG. 1, there is described a flask  10  of standard type e.g. containing medication in lyophilized form. The flask  10  comprises a cylindrical body  12  with a neck  14  defining an opening  16 . The neck  14  is surrounded by a cylindrical flange  18  which has a side face  20 , a top face  22 , and an inside face  24 . The flask is closed by a plug made of puncturable material  26  which is engaged in the opening  16  of the flask. The periphery  28  of the plug is pressed against the top face  22  of the flange, and a metal clamping capsule  30  fixes the plug in sealed manner onto the opening  16  of the flask  10 . 
     It will be understood on looking at FIG. 1 that the diameter D of the puncturable central portion of the plug is relatively small, with its diameter lying in the range 5 mm to 2 mm, depending on the size of the flask. 
     With reference now to FIGS. 2 to  4 , there is described a first embodiment of a syringe device suitable for fixing on a flask of the kind shown in FIG.  1 . The syringe device  40  is essentially constituted by a guide part  42  and a syringe  44  of conventional type fitted with a needle  45 . The guide part  42  is preferably circularly symmetrical about the axis XX′ and has a first end  46  for securing to the flask  10 , a second end  48  for receiving and guiding in translation the syringe  44 , and an intermediate common part  50 . The first end  46  comprises a first guide surface  52  of inside diameter D′ 2  that is designed to co-operate with the cylindrical portion  12  of the flask, which has a diameter D 2  that is slightly smaller than the diameter D′ 2 . The end  46  includes a second circularly symmetrical guide surface  54  designed to co-operate with the side face  20  of the flange  18  of the flask, said guide surface having an inside diameter D′ 1  that is slightly greater than the diameter D 1  of the flange  18 . Between the guide surfaces  52  and  54 , the end  46  of the guide part includes resilient snap-fastening elements  58  serving to secure the end  46  of the guide part  42  on the neck of the flask  10 . As can be seen more clearly in FIGS. 2 and 4, the end  46  of the guide part is connected in its common portion by a portion  60  forming a plate that is substantially orthogonal to the axis XX′ and that forms an integral portion of the guide part. This plate  60  is provided with an axial sleeve  62  which defines a central orifice  64  lying on the axis XX′ of the guide part. The central orifice  64  is extended by a frustoconical portion  66  facing towards the second end of the guide part. When the syringe  44  is mounted on the guide part, the end of the needle  45  lies inside the central orifice  64 . The bottom face  60   a  of the plate  60  is preferably provided with an annular rib  70  surrounding the orifice  64  and projecting from the face  60   a . This ensures that the guide part  42  is secured to the flask, with the resilient tongues  58  co-operating with the bottom face  24  of the flange when the rib  70  is pressed against the plug. Accurate fixing and good sealing is thus obtained between the plug and the guide part by the action of the rib on the resilient material forming the plug of the flask. Also preferably, although not essentially, a puncturable membrane  72  can be fixed to the face  60   a  of the plate  60 , thereby sealing the zone  76  inside the guide part, and thus ensuring that the space  76  containing the needle is kept sterile. 
     It will be understood that because of the presence of the resilient tongues  58 , the guide part is automatically secured to the neck of the flask merely by pushing the neck of the flask into the end of the guide part, without there being any need for some other action being performed. The resilience of the tongues  58  ensures that they operate automatically. 
     It would not go beyond the invention if the guide surface  54  were to be omitted. Under such circumstances, the surface  52  would need to be of adequate length in the direction of the axis XX′, e.g. 5 mm, so that it is capable, on its own, of positioning the guide part on the flask. 
     FIG. 4 b  shows a variant embodiment of the guide surface  52  and optionally of the guide surface  54 . It makes it possible to achieve very good centering of the guide part  42  on the flask in spite of dimensional tolerances applicable to the flask. The inside face  52   a  of the guide surface is provided with at least one longitudinal rib  53 , and preferably with three such ribs disposed at 120° intervals, and of a section that is triangular or similar. The edges of said ribs can be crushed to some extent along a diameter of the particular cylindrical body concerned, or of the flange, while still maintaining centering. 
     In dashed lines, FIG. 2 shows another variant embodiment of the guide part. In this variant, the puncturable membrane  72  is replaced by a film  73  (shown in dashed lines in the figure) whose periphery is fixed in sealed manner to the guide part  54 . This very thin sealed film has tear starters in its center. When the guide part is put into place on the flask, the plug of the flask applies pressure to the film  73 , thereby causing it to tear in its center. This ensures that the needle can pass through it freely. 
     To maintain sterile conditions in the inside zone  76  of the guide part, it is also possible to provide the inside face of the guide zone  52  with tapping  200 . A removable cap  202  having an outside thread  204  can then be screwed to the end of the guide part. 
     The syringe  44  is guided in translation inside the common portion of the guide part by means of an annular sealing ring  78  whose outside face  78   a  preferably has three sealing ribs  80 ,  82 , and  84  that co-operate with the guide part. The inside face  78   b  of the sealing ring  78  has a shoulder  86  co-operating with the syringe body  44 . Consequently, the sealing ring is entrained by the syringe when the syringe is pushed into the guide part. In contrast, the sealing ring is free relative to the syringe when the syringe is moved to be extracted from the guide part. The end  48  of the guide part preferably includes resilient blades  90  projecting into the inside of the guide part. In the storage position, as shown in FIG. 2, the ends of the resilient blades  90  are interposed between the ribs  82  and  84  that serve to hold the sealing ring  78  to some extent relative to the guide part. In this way, the syringe and the guide part are indeed secured mechanically to each other by means of the sealing ring  78  which also serves to provide dynamic sealing between the guide part and the syringe body. As also shown in FIG. 2, the guide part  42  preferably has a flange  92  on its outside face serving to protect the fingers of people handling the equipment while the syringe is being put back into its initial place inside the guide part after it has been used. 
     FIG. 5 shows a variant embodiment of the guide device. This variant consists solely in another embodiment of the plate  60  and of the sleeve  62 . In this embodiment, the plate element which is now referenced  60 ′ has a cylindrical sleeve  96  defining an axial bore  97  of large dimensions. In this axial bore, there is engaged an additional part  98 . This part  98  includes a plate-forming portion  100  provided with the rib  70 ′. The additional part  98  also includes a sleeve-forming portion  102  which is engaged in the cylindrical sleeve  96 . The sleeve  102  has a frustoconical end  104  and the central orifice  105 , in similar manner to the sleeve  62  including a frustoconical end  66 . It will be understood that when the extra part  98  is put into place in the sleeve  96 , a structure is reconstituted which is identical to that shown in FIG.  2 . The advantage of this technique lies in the fact that during the preliminary operations of preparing the syringe device, the syringe  44  is placed initially in the guide part  42  while the guide part is not yet provided with the part  98 , after which the part  98  is installed via the first end of the guide part. 
     FIGS. 6 a  to  6   b  show the syringe device in use. FIG. 6 a  shows both the syringe device  40  and the flask  10  together with its puncturable plug  26 . 
     FIG. 6 b  shows the syringe device  40  being put into place on the flask  10 . The guide part  42  is accurately positioned relative to the flask and thus relative to the plug by means of the guide surfaces  52  and  54 . In addition, the snap-fastening tongues  58  co-operate with the flange  18  of the flask, thereby holding the two parts together. 
     FIG. 6 c  shows the syringe being pushed into the guide part  42 . This is controlled by the presence of the sealing ring  78 . The needle  45  punctures the center of the plug  26 . It is then possible, by actuating the piston of the syringe, to cause the liquid contained in the syringe to penetrate into the flask  10 . After the two substances have been mixed together, the mixture prepared in this way is sucked back into the syringe. Thereafter it suffices to extract the syringe  44  from the guide part  42 , with the sealing ring  78  remaining captive in the guide part because of the presence of the resilient tongues  90 . 
     In addition, in both of these first two embodiments, the syringe is guided in translation in the guide part by means of the sealing ring  78  which also serves to provide sealing, and thus to ensure that the volume  76  containing the needle is kept sterile. These two functions could be obtained by providing for the syringe body  44  itself to have several, e.g. three, annular ribs that are spaced apart axially and that co-operate with the inside face of the common portion of the guide part. 
     With reference now to FIG. 7, there follows a description of a third embodiment of the syringe device. It differs from the first embodiment essentially by the fact that the sealing ring  78  is omitted and by the fact that the syringe  44  is guided in translation in the guide part  42  by means specifically provided for that purpose. The remainder of the device is identical in both cases and is therefore not described again. 
     Guidance in translation is provided by co-operation between internal guide surfaces of the guide part and certain portions of the body  47  of the syringe. In the example shown in FIG. 7, the end of the body  47  on which the needle  45  is mounted presents an endpiece  120 , a small diameter cylindrical portion  122 , and a cylindrical portion  124  of diameter larger than that of the common portion of the syringe body. 
     The inside face  50   a  of the common part  50  of the guide part has a diameter that is slightly greater than the outside diameter of the portion  124  of the syringe body, thereby forming a first guide surface. Inside the guide part there are provided four radially-extending guide fins  126  whose edges  126   a  are disposed on a circularly cylindrical surface whose diameter is slightly greater than that of the portion  122  of the syringe body. This defines a second guide surface. The distance between these two guide surfaces is large enough to provide very good guidance in translation of the syringe within the guide part, and thus accurate centering of the needle  45  relative to the plug  26 . 
     Naturally, only one surface need be provided, on condition that it is of sufficient length. 
     It can also be seen that the top ends  126   b  of the fins  126  constitute an abutment against further pushing in of the syringe by co-operating with the large-diameter portion  124  of the syringe body. This abutment ensures that after the syringe has been pushed into the guide part, the tip of the needle  45  has indeed passed through the plug  26  of the flask, but that it penetrates only very little into the flask. This figure also shows, at the top end of the guide part, reversible clip-forming tabs  130  suitable for co-operating with the shoulder  124   a  of the syringe body. The purpose of these tabs  130  is reliably to secure the syringe in translation with the guide part when the syringe is fully engaged in the guide part. This makes handling the rod for controlling the syringe piston more comfortable when injecting the liquid contained in the syringe and when sucking the mixture back out from the flask. 
     FIG. 7 shows another improvement which could be implemented equally well in both of the above embodiments. This improvement relates to recovering harmful gases that might possibly escape from the flask after the components have been mixed together. Because of the excess pressure that may result from making the mixture in the flask and from temporary and local deformation of the plug when the tip of the needle leaves the plug, harmful gases or a residual fraction of liquid can penetrate into the guide part and escape into the surrounding air. 
     To solve this problem, it is possible to place a part  140  of porous material such as a porous foam at the first end of the guide part. When the needle is being extracted from the flask, any gases escaping from the flask are absorbed, trapped, or blocked by the part  140 . Naturally, the needle passes through the part  140 . 
     For the same purpose, it is also possible to provide in the guide part  40  an orifice that is obstructed by a microporous filter  142  making it possible to compensate the excess pressure created by the escaping gases, by filtering said gases outside the guide part without their toxic components. This disposition is particularly advantageous if the quantity of gas created is large. 
     The filter also serves to compensate pressures inside and outside the guide part during movements of the syringe through the guide part. 
     It should be added that the syringe device of the invention serves not only to ensure that the needle of the syringe and the flask are accurately coaxial, but also to position the guide part accurately relative to the flask along the axis XX′. To monitor the extent to which the needle has penetrated into the flask, it therefore suffices to monitor the extent to which the syringe has penetrated into the guide part. This result can be obtained automatically by providing an abutment that limits the extent to which the syringe can be pushed into the guide part. 
     Although particular embodiments of the invention have been described in detail for purposes of illustration, various changes and modifications may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited except as by the appended claims and equivalents thereof.