Mixing syringe

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a mixing syringe, and $ more particularly, to a device for mixing a medicament with a suitable diluent to form a mixture suitable for injection.

. 2. Description of the Prior Art

Many drugs and medicinal products are subject to deterioration unless they are manufactured in dry powder form, and ^{1 u}which are brought into solution or into suspension in a suitable diluent immediately prior to use. For example, certain antibiotics^ vitamins and hormones do not retain their properties when packaged in solution form. Manufacturers of such products have therefore been required to market the powder and the diluent in separate flasks, ampuls or other receptacles, whereupon the· respective constituents are subsequently mixed together in a bottle. The composition or mixture is then drawn into a syringe and administered as soon as possible to 20 the patient, or is added to some other, parenteral solution forimmediate use. It is readily apparent.that the use of separate flasks or ampuls increases the manufacturing cost . of . the product, increases the possibility of spilling the constituents during the mixing operation and increase the possibility of 25 contamination of such constituents during the mixing operation and during the subsequent transferring operation of same to the syringe.

In this connection, the: mixing of certain products must be performed, with extreme caution. For example, the mixing of 30 nitrogen mustard, which is used in cancer therapy, is an extremely dangerous operation causing severe caustic burns if brought accidentally into contact with the skin. .

In an attempt , to overcome some of the problems and hazards referred to above, there has been proposed various 35 syringe assemblies formed of a. plurality of compartments,. A medicament is disposed in one of the compartments and a diluent is disposed in another one of said, compartments, whereby the respective substances are mixed together immediately prior to use. The major difficulty and disadvantage of such known syringe assemblies reside in the mixing operation of the respective substances therein. In this connection, it has been found that the known syringe assemblies do not provide sufficient or adequate means for effectively and efficiently mixing tJie respective substances prior to use.

The present invention overcomes the above difficulties and disadvantages by providing a mixing syringe which maintains the respective substances in separate compartments, and which includes novel shuttle means for quickly and effectively mixing said substances in a manner hereinafter described.

SUMMARY OF THE INVENTION

The mixing syringe of the present invention includes separate chambers formed respectively in a barrel and a 55 plunger for carrying selective constituents of a composition; said barrel and plunger each having a piston reciprocably mounted therein for defining the respective chambers. A mixing shuttle is provided having conduit means mounted thereon for conjoint movement, therewith. The barrel; plunger and 60 mixing shuttle are connected together whereby the opposite end portions of the conduit means are respectively connected to the barrel piston and the plunger piston for conjoint movement therewith. The end portions of the conduit means have terminal ends respectively penetrating the pistons for 65 establishing communication between the respective chambers via said conduit means for mixing the respective constituents therein in response to the reciprocabie and conjoint movement of the shuttle means and the pistons relative to the barrel and the plunger. 70

In another embodiment of the invention, the plunger is replaced with an expansible chamber for carrying a selected constituent of the composition; said chamber having a forward wall portion connected to a conduit end portion for conjoint movement therewith. In this embodiment,, the end portions of 75 the conduit means have terminal ends respectively penetrating the barrel piston and the expansible chamber for establishing communication between the respective chambers via said conduit means for mixing the respective constituents therein in response to the reciprocabie movement of the shuttle means and the expansion and contraction of the expansible chamber.

Suitable outlet means are provided on the barrel for dispensing the mixture or.composition therefrom.

Accordingly, an object of the present invention is to provide a mixing syringe for mixing a dry powdered medicinal substance-with a suitable diluent to form a mixture suitable for injection, and. to provide a device by which the mixing and the injection can be effected successively.

The above and other objects, features and advantages of the present invention will become more apparent from a consideration of the following detailed description when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view, with parts in section and parts broken away , of the mixing syringe assembly constructed in accordance with the present invention;

FIG. 2 is a view similar to FIG. 1 illustrating the component parts coupled together;

FIG. 3 is a view similar to FIG. 2 illustrating one position of. the mixing syringe assembly during the mixing Operation;

FIG. 4 is a view similar to FIG. 3 illustrating the mixing syringe in position for dispensing the composition therefrom;

FIG. 5 is a side elevational view, with parts in section, illustrating another embodiment of the invention;

FIGI 6 is a view similar to FIG. S illustrating the component parts coupled together;

FIG. 7 is a view similar to FIG. 6 illustrating one position of the mixing syringe assembly during the mixing operation; and

FIG. 8 is a view similar to FIG. 7 illustrating the mixing syringe in position for dispensing the composition therefrom;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, and more particularly to FIGS. 1 through 4, numeral 10 represents the mixing syringe constructed in accordance with the present invention. Syringe 10 includes a barrel 12 formed of glass, plastic or other suitable , material. In accordance with conventional construction, barrel 12 is provided with a tubular wall 14 and a transversely extending front wall .16 from which a tip or nosepiece 1.8 projects outwardly and serves as a dispensing outlet. In this connection, nosepiece 18 is.provided with a bore 20 establishing communication between the interior of barrel 12 and nosepiece 18. Cap 22 is separably mounted on nosepiece 18 by suitable fastening means, indicated generally by numeral 24, and serves as a closure for the barrel dispensing outlet during the mixing operation. At such time as the mixture or composition is to be dispensed from the barrel outlet, cap 22 is removed and replaced with a conventional hypodermic needle in a manner hereinafter described. The rear end portion of tubular wall 14 is open and is provided with a transversely extending flange portion 26 projecting outwardly and serving as finger gripping portions for barrel 12.

Reciprocably mounted within the open end of barrel 12 is a piston 28 formed of a flexible, resilient and penetrable material such as rubber or the like. Piston 28 constitutes a cylindrical plug or seal and serves to define a forward chamber 30 in barrel 12 for carrying one constituent of a composition.

Piston 28 includes a conical shape cavity portion 32 formed, axially therein and which is tapered toward the front end surface 34 thereof to provide wall portion 36 having a reduced thickness between.the bottom or apex of cavity 32 and the front end surface 34 pf piston 28, at the axis thereof. The rear end surface 38 of piston 28 defines an annular flange 40 hav_rv ing a centrally provided opening 42 therein affording access to cavity portion 32. The construction is such as to permit piston.

3,570,486 to be separably connected to a mixing shuttle of the syringe assembly.

Mixing shuttle 44 is provided with a tubular wall 46 reciprocably mounted through the open end of barrel 12 and located rearwardly of piston 28. Shuttle 44 may be formed of glass, plastic or other suitable material. Tubular wall 46 includes a transversely extending flange portion 48 projecting outwardly from the rear end thereof and serving as finger gripping portions for shuttle 44. Tubular wall 46 further includes a transversely extending wall portion SO projecting radially inwardly from the forward end thereof and to which is fixedly secured conduit means 52 extending axially of tubular wall 46; said conduit 52 having a bore 54 extending longitudinally the length thereof. The construction is such that conduit 52 moves conjointly with the reciprocable movement of shuttle 44.

The end portions 56 and 58 of conduit 52 are provided with head portions 60 and 62 respectively, for interconnecting various components of the syringe assembly. In this connection, head portion 60 has a surface configuration complementary to the taper of cavity 32 in piston 28, and includes a tapered terminal end 64 projecting forwardly therefrom. The construction is such that the axis of terminal end 64 is coincident with the axis of piston 28 for subsequently piercing wall portion 36 of piston 28. Accordingly, head portion 60 and terminal end 64, together with piston cavity 32 and piston flange 40, provide coacting means for interengaging the end portion 56 of conduit 52 with piston 28 upon slidable movement of conduit 52 relative to said piston. Head portion 62 similarly includes a tapered terminal end 66 for interconnecting the end portion 58 of conduit 52 to a plunger component of the syringe assembly.

Reciprocably mounted within shuttle 44 is a plunger assembly indicated generally by the numeral 68. Plunger 68 may be formed of glass, plastic or other suitable material, and includes a tubular wall 70 telescopically disposed within shuttle 44. Tubular wall 70 is closed at the rear end 72 thereof and may be provided with a transversely extending flange portion 74 projecting radially outwardly therefrom and serving as finger gripping portions for plunger 68. Tubular wall 70 further includes another transversely extending flange portion 76 projecting radially inwardly from the forward end thereof. Reciprocably mounted within plunger 68 is a piston 78 formed of a flexible, resilient and penetrable material such as rubber or the like. Piston 78 is suitably sized to constitute a cylindrical plug or seal for defining a rearward chamber 80 in plunger 68 for carrying another constituent of the composition. In this connection, piston 78 is similar in construction to piston 28, and includes a conical shape cavity portion 82 formed axially therein and which is tapered toward the rear end surface 84 thereof. Accordingly, there is provided a piston wall portion 86 having a reduced thickness between the bottom or apex of cavity 82 and the rear end surface 84 of piston 78, at the axis thereof. The forward end surface 88 of piston 78 defines as annular flange 90 having a centrally provided opening 92 therein affording access to cavity portion 82.

Referring again to mixing shuttle 44, the head portion 62 of conduit end portion 58 is provided with a surface configuration complementary to the taper of cavity 82 in piston 78. The construction is such that the axis of terminal end 66 of head portion 62 is coincident with the axis of piston 78 for subsequently piercing wall portion 86 of piston 78. It is now apparent that head portion 62 and terminal end 66, together with piston cavity 82 and piston flange 90, provide coacting means for interengaging the end portion 58 of conduit 52 with piston 78 upon slidable movement of conduit 52 relative to said piston.

Having described the component parts of the novel mixing syringe of the present invention, attention is now directed to the operation thereof as embodied in FIGS. 1 through 4. Chambers 30 and 80, located in barrel 12 and plunger 68 respectively, are illustrated as carrying the constituents of the composition. It will be appreciated that while chamber 80 is il lustrated as carrying the dry powder medicament and chamber 30 carrying the suitable diluent, the location of the respective constituents with respect to said chambers can be reversed. Furthermore, it is readily apparent that the syringe of the present invention can be used for mixing medicinal products which do not include a powder constituent. In those situations where one of the constituents is in powder form, it is preferable to connect the mixing shuttle to the chamber carrying the dry constituent prior to connecting the mixing shuttle to the chamber carrying the diluent.

Accordingly, shuttle 44 and plunger 68 are slidably moved relative to one another for interengaging conduit end portion 58 with piston 78, whereby piston cavity 82 receives the head portion 62 of conduit 52. The arrangement is such that terminal end 66 of conduit 52 pierces piston wall portion 86 for establishing communication between chamber 80 and the bore 54 of conduit 52. The sealing arrangement of piston 78 relative to plunger wall 70, and the thickness of piston wall portion 86, are such that coupling of conduit end portion 58 with piston 78 is readily achieved without materially displacing the piston within plunger wall 70; whereupon piston 78 will thereafter move conjointly with conduit end portion 58. Mixing shuttle 44 is then connected to chamber 30 by slidably moving shuttle 44 and barrel 12 relative to one another for interengaging conduit end portion 56 with piston 28. The coupling arrangement is similar to that described with respect to chamber 80 whereby piston cavity 32 receives the head portion 60 of conduit 52, and terminal end 64 of conduit 52 pierces piston wall portion 36 for establishing communication between chamber 30 and the bore 54 of conduit 52. It will be noted that during the coupling operations described above, the piston flanges 40 and 90 of pistons 28 and 78 respectively, must be sufficiently resilient so as to be initially displaced within the respective piston cavities 32 and 82 and thereafter reassume their normal positions whereby said flanges 40 and 90 will abut against the respective shoulders of conduit head portions 60 and 62. In this connection, FIG. 1 illustrates in phantom conduit end portion 56 after it has been slidably moved within barrel 12 a distance sufficient to permit piston flange 40 to reassume its normal position. It is now apparent that communication is established between chambers 30 and 80 via bore 54 of conduit 52 for mixing the respective constituents of the composition therein in response to the reciprocable and conjoint movement of shuttle 44 and pistons 28 and 78 relative to barrel 12 and plunger 68. In other words, when barrel 12 and plunger 68 arc fixedly held in the position illustrated in FIG. 3, forward movement of shuttle 44 will force the diluent in chamber 30 through the bore 54 of conduit 52 and into contact with the powder medicament in chamber 80. Thereafter, retracted movement of shuttle 44 will force the mixed constituents from chamber 80 to chamber 30 via conduit 52. Further reciprocable movement of shuttle 44 will transfer the mixed constituents alternately between the respective chambers for quickly and effectively mixing said constituents prior to use. Flange portion 76 of plunger 68 serves as a stop to prevent piston 78 from being inadvertently withdrawn from plunger 68 during the mixing operation. After the constituents have been sufficiently mixed, shuttle 44 is positioned to locate the mixture or composition in chamber 80. Barrel closure cap 22 may now be removed for mounting the hub 94 of hypodermic needle 96 on barrel nose piece 18 in a conventional manner. Mixing shuttle 44 can now be positioned to locate the composition in chamber 30, as shown in FIG. 4, whereby the composition will be dispensed from the barrel outlet and through hypodermic needle 96 in response to the combined forward movement of plunger 68 and shuttle 44 relative to barrel 12.

FIGS. 5 through 8 represent another embodiment of a mixing syringe 100 constructed in accordance with the present invention wherein plunger 68 is replaced with an expansible chamber 110 for carrying a selected constituent of the composition. In this connection, the structural details of the respective syringes 10 and 100 are essentially similar to one

3,570,486 another, and accordingly, those details of syringe 100 common to syringe 10 carry similar reference numerals designated with a prime notation; said common details and components operating and functioning in a similar manner so that a detailed description of same is not deemed necessary.

Expansible chamber 110 has a forward wall portion 112 slidably mounted within shuttle 44'and an axially extensible wall portion 114 extending rearwardly thereof which is closed by rear wall portion 116. Expansible chamber 110 may be formed of a flexible, resilient material such as rubber, plastic or the like, and constitutes a bellows which defines chamber 118 for carrying the powder medicament. In the preferred construction, forward wall portion 112 is formed of a penetrable material, such as rubber, and includes a conical shape cavity portion 120 formed axially therein and which is tapered toward the rear end surface 122 thereof. Accordingly, there is provided a wall portion 124 having a reduced thickness between the bottom or apex of cavity 120 and the rear end surface 122, at the axis thereof. The forward end surface 126 of forward wall portion 112 defines an annular flange 128 having a centrally provided opening 130 therein affording access to cavity portion 120.

Referring to mixing shuttle 44'the head portion 62'of conduit end portioh 58' is provided with a surface configuration complementary to the taper of cavity 120 in forward wall portion 112. The construction is such that the axis of terminal end 66' of head portion 62' is coincident with the axis of expansible chamber 110 for subsequently piercing wall portion 124 of forward wall portion 112. It is now apparent that head portion 62' arid terminal end 66', together with forward wall cavity 120 and forward wall flange 128, provide cbacting means for interengaging the end portion 58'with the forward wall portion 112 of expansible chamber 110, and piercing wall portion 124 upon slidable movement of forward wall portion 112 relative to conduit 52'.

In operation, shuttle 44' and the forward wall portion 112 of expansible chamber 110 are slidably moved relative to one another for interengaging conduit end portion 58' with forward wall portion 112, whereby forward wall cavity 120 receives the head portion 62' of conduit 52'. The arrangement is such that terminal end 66' of conduit 52' pierces wall portion 124 for establishing communication between chamber 118 and the bore 54' of conduit 52'. The coupling operation is similar to that described with respect to the embodiment of FIGS. 1 through 4 whereby the forward wall portion 112 of expansible chamber 110 will thereafter move conjointly with conduit 0 PORTION 58' Mixing shuttle 44' is then connected to chamber 30' by slidably moving shuttle 44' and barrel 12' relative to one another for interengaging conduit end portion 56' with piston 28' in the manner heretofore described. It is now apparent that communication is established between chambers 30' and 118 via bore 54' of conduit 52' for mixing the respective constituents of the composition therein in response to the reciprocable movement Of shuttle 44' and the expansion and contraction of expansible chamber 110. In other words, piston 28' and the forward wall portion 112 of expansible chamber 110 are coupled to conduit end portions 56' and 58' respectively, for conjoint movement therewith. Forward movement of shuttle 44' relative to barrel 12', as shown in FIG. 7, will force the diluent in chamber 30' through the bore 54' of conduit 52' and into contact with the powder medicament in chamber 118 thereby expanding expansible chamber 110. Thereafter, retracted movement of shuttle 44' relative to barrel 12' will reduce the pressure in chamber 30' and thus serve to transfer the mixed constituents from chamber 118 to chamber 30', via conduit 52', thereby contracting expansible chamber 110. Further reciprocable movement of shuttle 44' will transfer the mixed constituents alternately between the respective chambers for quickly and effectively mixing said constituents prior to use. The dispensing operation is performed similarly to that described with respect to the embodiment of FIGS. 1 through 4, whereby shuttle 44' is positioned to locate the mixture or composition in chamber

118. Barrel closure cap 22' may now be removed for mounting the hub 94' of hypodermic needle 96' on barrel nose piece 18'. Mixing shuttle 44' is then positioned to locate the composition in chamber 30', as shown in FIG. 8, whereby the composition will be dispensed from the barrel outlet and through hypodermic needle 96' in response to the combined forward movement of expansible camber 110 and shuttle 44' relative to barrel 12'.

Accrodingly, there is now provided a mixing syringe assembly which maintains the respective constituents in separate compartments and which includes a shuttle assembly for interconnecting the compartments for quickly and effectively mixing the constituents prior to use. Plunger 68 and expansible chamber 110, respectively containing selected constituents, can be manufactured, supplied and stored separately for selective use and coupling with the mixing syringe as required. Furthermore, whereas the forward wall portion 112 of expansible chamber 110 is preferably illustrated as being slidably mounted within shuttle 44', this construction is merely illustrative and is not to be deemed a limitation on the invention. For example, the embodiment of FIGS. 5 through 8 can be readily constructed with conduit end portion 58' extending beyond the open end of shuttle 44' and being connected to the forward wall portion 112 of expansible chamber 110 in the manner heretofore described, without otherwise altering the mixing and dispensin operation. If desired, the mixed constituents can be added to some other parenteral solution for immediate use.

While specific embodiments of the invention have been shown and described in detail, it will be readily understood and appreciated that various changes or modifications thereof may be made without departing from the spirit and scope of the invention as set forth in the appended claims.