Patent Publication Number: US-7896849-B2

Title: Syringe for medical interventions and kit for reconstituting extemporaneous substances

Description:
The present invention concerns a syringe and a kit for reconstituting extemporaneous substances, comprising said syringe. 
     The invention concerns in particular a syringe of the type comprising:
         a syringe body in which a passage for the circulation of fluid is defined, said circulatory passage being extended by a main element for fluidic connection to a complementary volume, and   a movable piston inside the body of the syringe defining, with the syringe body, a chamber for the containment of fluid, which containment chamber opens out through said circulatory passage.       

     In the medical field, it is known to use a syringe for effecting the reconstitution of an extemporaneous mixture constituted by a solvent and a cytotoxic active ingredient. The active ingredient is for example used for the treatment by chemotherapy of patients affected by cancer. 
     As is known per se, the solvent is commonly contained initially in a perfusion bag, while the cytotoxic active ingredient, generally in powder form, is initially contained in a bottle. For the preparation of the extemporaneous mixture, the practitioner removes solvent from the bag in order to introduce it into the body of a syringe. The solvent thus removed is introduced into the bottle, where it mixes with the powder constituting the active ingredient. The mixture thus reconstituted is re-aspirated into the syringe, before being transferred back into the perfusion bag. This is then placed on a perfusion line for gradually administering its contents to the patient. 
     During the successive transfers, the excess air contained in the bottle, at the time of introduction of the solvent, is evacuated into the atmosphere through a vent provided for this purpose. The solvent vapours, and especially the gaseous emanations resulting from the active ingredient, escape through said vent. They may be dangerous for the medical staff carrying out the transfer. Thus, it is known to equip the vent with a filter having openings of 0.2 μm in order to retain the harmful molecules in the bottle. 
     However, the actual efficacy of such a filter is questionable and the utilisation of said filter is delicate and expensive. 
     The aim of the invention is therefore to propose a syringe avoiding such gaseous emissions which may be harmful to the medical staff. 
     To this end, the subject of the invention is a syringe of the aforesaid type, characterized in that the syringe body defines a closed space in which the piston is movably mounted, the piston defining in this closed space, in addition to the fluid containment chamber, an auxiliary return chamber, the syringe body defining a return passage opening out into said auxiliary return chamber, and in that said return passage is extended by an auxiliary element for connection to said complementary volume. According to particular embodiments, the syringe includes one or more of the following characteristics:
         said auxiliary connection element comprises a hollow needle;   it comprises a piston actuating rod linked to the piston and protruding out of the syringe body from a rearward end, said circulatory passage being formed at the forward end of the syringe body, and said return passage is formed in the vicinity of the rearward end of the syringe body and the auxiliary connection element extends along the length of the syringe body from the return passage to the vicinity of the forward end;   the main element for fluidic connection includes a distributor comprising a base defining at least three paths for circulation and a closure means, movable in relation to the base, a first path being connected to said circulatory passage, a second path comprising a duct for connection to said complementary volume, and a third path comprising a transfer duct, said closure means being movable between a transfer position, in which the first and third paths are connected, and a preparation position, in which the first and second paths are connected.   the syringe body and the distributor are inseparable;   the transfer duct comprises a hollow needle; and   said hollow needle of the transfer duct has a perforable and resiliently deformable hood covering the hollow needle;   the connecting duct comprises a hollow needle;   the free end portions of the hollow needles of the auxiliary connection element and of the connecting duct are spaced by less than 1 cm.       

     A further subject of the invention is a reconstitution kit comprising a syringe as defined above and a complementary volume adapted for simultaneous connection to the containment chamber and to the auxiliary return chamber respectively via the main element for fluidic connection and the auxiliary connection element. 
    
    
     
       The invention will be understood more clearly on reading the following description, provided solely by way of example and with reference to the drawings, in which: 
         FIG. 1  is an exploded perspective view of a reconstitution kit including a syringe according to the invention; and 
         FIGS. 2 to 6  are views in longitudinal section of the kit at successive stages of use. 
     
    
    
     The reconstitution kit  10  illustrated in  FIG. 1  is intended in particular for the extemporaneous preparation of a cytotoxic or other drug for the treatment of cancers or the like by chemotherapy. 
     The kit basically includes a syringe  12  and a bottle initially containing an active ingredient in powder form. The bottle  13  is formed, for example and as illustrated in  FIG. 4 , of a body  14  of non-deformable glass closed by a protective cap  15 , the body defining a closed space. It is initially filled with an active ingredient in powder or liquid form. The syringe  12  is suitable for being connected on the one hand to the bottle  13  and on the other hand to a perfusion bag  16 . 
     More precisely, the syringe  12  comprises a syringe body  18  bearing graduations  19  and a three-way distributor  20  permitting the selective connection of a chamber of the syringe body selectively to the bottle  13  or to the perfusion bag  16 . 
     As illustrated in  FIGS. 2 to 6 , the syringe body  18  comprises a cylindrical wall  22  of generally circular section closed, at a forward end, by a transverse wall  24  defined by a base  26  of the distributor  20 . The wall  24  is pierced by a passage  28  for circulation of a fluid entering or leaving the syringe. 
     The passage  28  is extended by a duct  30  forming a first path of the distributor  20 . At the rearward end of the syringe body  18 , the cylindrical wall  22  is closed by a transverse wall  31  pierced in its centre by an opening  32  for the circulation of a piston rod  34 . 
     The piston rod  34  is disposed along the axis of the syringe body and has at its end received in the syringe body a piston  36  displaceable axially from one end to the other of the syringe body, and having a peripheral lip  38  providing a seal along the wall. At its end protruding from the syringe body, the piston rod  34  has a transverse bearing surface  38 . A sealing O-ring  40  is arranged against the transverse wall  31  at the periphery of the piston rod  34 . The seal is compressed by a bearing washer  42 . 
     Thus, the piston  36  defines in the syringe body, at the front, a fluid containment chamber  44 . This chamber is generally closed and opens only through the circulatory passage  28 . On the other side of the piston  36  an auxiliary return chamber  46  for gaseous excess is defined. The chambers  44  and  46  are complementary and together form a closed space defined by the syringe body  18 . 
     The auxiliary return chamber  46  is closed and opens only through a return passage  48  for gaseous excess. This passage is extended by an auxiliary element  50  for connection to the bottle  13 . 
     The auxiliary connection element  50  is formed of a metal or plastics tube of reduced section, for example of 0.5 mm inside diameter. The latter includes a straight main portion  50 A and two elbowed end portions  50 B,  50 C extend generally perpendicularly to the straight main portion  50 A. 
     The straight portion  50 A has a length very slightly greater than the length of the syringe body  18 . The rearward elbowed end  50 B is engaged in the return passage  48 . 
     The straight main portion  50 A extends along the length of the cylindrical wall  22 . For holding the tube  50 , the syringe body has on its outer surface a channel  52  defined by two longitudinal lips  54  visible in  FIG. 1 . 
     The curved forward end  50 C is bevelled at its end marked  50 D, so that the auxiliary connection element  50  constitutes a hollow needle. The bevelled end  50 D is suitable for engaging through the perforable protective cap  15  closing the neck of the bottle  13 . 
     The base  26  of the distributor  20  is formed for example of injection-moulded plastics material. 
     The wall  24  forming the end of the syringe body is bordered externally by a collar  60  permitting the rigid connection of the cylindrical wall  22 . This rigid connection is effected inseparably, for example by adhesive securing or ultrasonic welding, so that the distributor cannot be separated from the syringe body  18 . 
     The base  26  defines a cylindrical seat  62  in which a sliding tap  64  of the distributor is received. The tap passes through the base from side to side and is equipped at each end with an operating member  66 ,  68 . 
     Besides the duct  30 , two other ducts of the distributor open out into the seat  62 . The three ducts of the distributor extend in the same plane and are offset by an angle of 90°, as illustrated in  FIG. 2 . 
     A duct  70  for connection to the bottle  13  forms a second path of the distributor. It comprises a hollow needle  72  protruding from the base  26 . The needle  72  extends parallel to the elbowed portion  50 C and is intended, like the latter, to penetrate into the bottle through the perforable protective cap  15 . The bevelled ends of the needles  50  and  72  are arranged in proximity to each other and are preferably spaced by less than 1 cm and preferably by 1 to 3 mm. 
     The base  26  has a collar  74  surrounding the protruding end of the needle  72 . The collar defines a space for receiving the neck of the bottle  13  and has profiles  76  for resilient engagement behind the neck in order to effect the mechanical connection of the bottle and the distributor. 
     The elbowed portion  50 C extends in the space defined by the collar  74 , the portion  50 C and the needle  72  extending parallel to one another for the perforation of the protective cap  15 . 
     The third path of the distributor comprises a duct for transfer to the perfusion bag  16 . Said duct is equipped with a hollow needle  82  protruding from the base  26 , in a generally cylindrical socket  84  provided in the base and suitable for receiving a tip  86  of the perfusion bag  16 . 
     As is known per se, the tip  86  is generally cylindrical and is perforable to permit access to the bag through an access duct  88 . 
     The protruding end of the needle  82  is covered over its entire length by a perforable resilient hood  90  in the form of a bellows suitable for being compressed axially along the needle  82 . 
     The tap  64  is mounted to be rotatable about its axis, the latter extending perpendicularly to the plane in which the ducts  30 ,  70  and  80  extend. 
     A peripheral groove  92  is provided on the tap  64  to permit the selective connection of the ducts. The groove extends through 180°. Thus the tap is adapted such that, in a first position, termed transfer position, it effects the connection of the ducts  30  and  80 , the duct  70  being closed and, in a second position, termed preparation position, it effects the connection of the ducts  30  and  70 , the duct  80  being closed. 
     The reconstitution kit is used in the following manner. 
     Initially, the bag  16  and the bottle  13  are not connected to the syringe  12 , as illustrated in  FIG. 2 . The syringe is stored in a sterile package. 
     After being taken out of the package, the syringe  12  is first connected to the bag  16  via the needle  82 . To this end, the tip  86  of the bag is engaged in the socket  84 , so that the hood  90  is perforated by the needle  82  and retracts along said needle. The bevelled end of the needle  82  pierces the tip of the bag and thus comes into contact with the solvent contained in the bag, as illustrated in  FIG. 3 . 
     With the tap of the distributor in its transfer position and connecting the ducts  30  and  80 , the piston  36 , initially pressed against the front wall  24 , is drawn towards the rear. By the action of the displacement of the piston  36 , solvent is gradually drawn from the bag and is received in the containment chamber  44 , as illustrated in  FIG. 3 . The air contained in the auxiliary chamber  46  is gradually evacuated via the auxiliary connection element  50 . The air is expelled into the atmosphere, without any consequence, since the air is sterile. 
     After the chamber  44  is filled with a satisfactory amount of solvent, the bottle  13  is connected. To this end, the neck of the bottle is introduced into the space defined by the collar  74 . The protective cap  15  is then perforated at the same time by the needle  72  and the needle  50 . 
     The tap  64  is then turned through 90° in order to be brought into its preparation position, so that the ducts  30  and  70  are connected to each other, the duct  80  being isolated. In this position, the containment chamber  44  is connected to the bottle  13  via the needle  72 , while the auxiliary return chamber  46  is also connected to the bottle  13  by the auxiliary connection element formed by the needle  50 . 
     For correct operation, the bottle is placed with its neck facing upwards and, as illustrated in  FIG. 4 , the piston is then pushed forwards, leading to the expulsion of the solvent towards the inside of the bottle through, in succession, the ducts  30  and  70 . Simultaneously, the excess gas contained in the bottle  13  is aspirated into the auxiliary return chamber  46  through the needle  50 . The excess gas contained in the bottle is transferred to the return chamber by the combined action of the over-pressure arising in the bottle  13  and the aspirating action of the auxiliary chamber  46 , owing to the displacement of the piston  36 . 
     All the solvent contained in the containment chamber  44  is thus transferred to the bottle. The solvent then mixes with the powder constituting the cytotoxic active ingredient. 
     The bottle  13  is then turned over, so that the free end of the needle  72  is in contact with the mixture, as illustrated in  FIG. 5 . The piston  36  is then displaced towards the rear of the syringe body by pulling on the rod  34 , as illustrated in  FIG. 5 . The mixture is thus re-aspirated into the containment chamber  44  through, in succession, the ducts  70  and  30 . 
     Simultaneously, the gas previously aspirated into the auxiliary return chamber  46  is reintroduced into the bottle  13 , to occupy the space left free by the mixture evacuated to the containment chamber  44 . 
     All the mixture is thus re-aspirated into the syringe. As illustrated in  FIG. 6 , the tap  64  is then brought into its transfer position, effecting the connection between the ducts  30  and  80 . The mixture contained in the containment chamber  44  is then reintroduced into the bag  16  through, in succession, the ducts  30  and  80  by the action of the piston  36  pushed axially towards the front of the syringe body. During this transfer, the bottle  13  remains connected and gas drawn from the bottle is aspirated into the return chamber. Thus a slight under-pressure is produced in the bottle  13 . 
     After the transfer of all the mixture contained in the containment chamber  44  or of a volume determined by means of the graduations of the syringe, the bag  16  is separated from the syringe by disengagement of the tip  86  from the socket  84 . By the action of the resilience of the hood  90 , the latter expands along the needle  82  to completely cover the end of same. Thus, the mixture still contained in the needle is confined inside the hood  90 , avoiding any transfer of the mixture in liquid and gaseous form to the outside. 
     With such a device, no gaseous emission containing molecules of the cytotoxic active ingredient is released into the atmosphere. In fact, the gaseous emissions which may occur in the bottle during the reconstitution of the extemporaneous mixture during the different stages of use of the syringe are systematically confined in the bottle and/or in the auxiliary return chamber  46 . Since the bottle  13  and the syringe  46  remain definitively connected, no contact occurs between the inside of the bottle and the chamber  46 , and the outside. 
     It will be imagined that with such a device, the operator is protected against any pollution resulting from the use of the cytotoxic active ingredient.