Abstract:
The present invention relates to multi-compartment devices having a pre-applied dispensing element. The device is adapted for dispensing multi-component compositions that are kept separate prior to use. Supplying a pre-applied dispensing element facilitates and simplifies the dispensing operation during use and reduces the chance of misuse due to improper application of the mixing element, loss and/or damage of the component.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention is related to multi-compartment devices for storing, and dispensing viscous substances. In particular, the invention relates to a multi-compartment device having dispensing tips for dispensing an admixture. 
       BACKGROUND 
       [0002]    Dental practitioners utilize syringes for a variety of tasks and procedures, including storing and dispensing substances used in dental procedures. Many compositions have a single component, but many others are composed of multiple components that are kept separate before a procedure, including, but not limited to, whitening compositions, impression materials, dentifrices and the like. 
         [0003]    Multi-barreled or multi-compartment devices are often utilized to store the multiple components of a composition and may also be used to mix and dispense the composition for use. As it is typically desired to keep the components separate to prevent any premature interaction, it is important for a device to incorporate features that maintain the integrity of the composition during storage. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention relates to multi-compartment devices having a pre-applied dispensing element. The device is adapted for dispensing multi-component compositions that are kept separate prior to use. Supplying a pre-applied dispensing element facilitates and simplifies the dispensing operation during use and reduces the chance of misuse due to improper application of the mixing element, loss and/or damage of the component. 
         [0005]    Many multi-component compositions are also typically mixed prior to use to properly combine the constituents in order to form an active and/or working composition. In one embodiment, a pre-applied dispensing element includes a mixing element, for dispensing and/or mixing the compositions. Supplying a pre-applied dispensing and/or mixing element facilitates and simplifies the dispensing operation during use and reduces the chance of misuse due to improper application of the mixing element, loss and/or damage of the component. 
         [0006]    In one aspect, the tip may serve as a dispensing means. In another aspect, the tip may serve both as a dispensing and a mixing means. 
         [0007]    The present invention relates to a multi-chambered device for storing and dispensing the material components of an admixture, including a housing having at least two chambers, each of said chambers having an outlet and an inlet with full fluid communication between the inlet and the outlet. A dispensing and/or mixing tip may be attached to the housing about the outlets of the chambers. The tip may have a generally axial bore, an inlet and an outlet. The device may include a unitary construction multi-plunger having juxtaposed plungers integrally molded from a polymeric material. 
         [0008]    In one aspect, multi-compartment devices may in general be in the form of a multi-barreled syringe, in particular double-barreled assemblies. The double-barreled syringes may include double-plungers. In another aspect, other numbers of barrels are also conceived and contemplated. 
         [0009]    The multi-compartment devices include sealing systems for keeping the components separate. In one embodiment, a multi-compartment device incorporates features, for example, formations, that may be adapted to allow the components of a composition to remain substantially segregated and sealed off until use. Such features may be adapted to cooperate with corresponding features on the rest of the device. 
         [0010]    At least one sealing system may be configured for substantially sealing the outlets of the chambers during storage, and at least one formation maybe configured for effecting the unsealing of the outlets of the chambers. In one example, at least a portion of the sealing system may be disposed within the bore of the tip. For example, the at least one seal breaking components may be configured to puncture or remove the seal when applying pressure to the contents of the chambers from the inlet ends. 
         [0011]    In one exemplary embodiment, such features, once activated to allow the contents of a compartment to exit the compartment, may be irreversible. In one aspect, the vessel, compartments may include an inert and/or unreactive substance that may act as a plug and/or sealant that may be forced out to allow mixing of the components of a composition. 
         [0012]    In one embodiment, the tip may include at least one cap and at least one plug shape element adapted to be disposed inside the at least one cap. A mixing element is attached and integral with the plug shape element, and maybe adapted for introducing the plug shape element into the barrel region of the syringe body. The pockets or hollow interiors of the barrel or barrels may have a corresponding feature for receiving the plug shape element so that the exit openings of the barrel or barrels may be closed by the plug shape element. The cap of the tip may also include threads adapted for attaching to the barrel or barrels by screwing onto the base of the barrel or barrels and a ledge for pushing the plug element on the mixing element onto the pocket or pockets of the barrel or barrels, closing the openings. 
         [0013]    In one embodiment, the at least one cap plug reversibly plugs the outlet of a chamber. 
         [0014]    In another embodiment, the at least one cap plug irreversibly unplugs the outlet of a chamber when removed. 
         [0015]    In another embodiment, the tip may include a mixing element adapted to be disposed inside the tip and a separate plug element adapted for fitting into the exit opening end of the barrel or barrels. The plug element may be forced into place on the barrel or barrels by attachment of the tip. 
         [0016]    In another aspect, the features may include seals that may be forced and/or broken so as to allow the contents of a compartment to exit. 
         [0017]    In one embodiment, a seal, such as a foil seal, may be introduced at the top of the barrel or barrels to seal off the content or contents. A formation, for example, a pointed formation, is adapted for breaking the seal may be introduced to the barrel or barrels before the barrel or barrels are filled with compositions. During use, the user may push on the plunger or plungers, driving the formation through the foil to open the barrel or barrels. 
         [0018]    In another embodiment, a removable seal, which may be a foil seal, may be introduced at the top of the barrel or barrels to seal off the content or contents. The barrel or barrels may be modified to include a cap which may be attached to the barrel or barrels with a living hinge. The cap may include a mixing element and adapted for attaching onto the opening end of the barrel or barrels. When the seal is removed, the cap may be onto the barrel or barrels for use. 
         [0019]    In another exemplary embodiment, the multi-compartment devices may include a switching assembly that may allow the multiple chambers to be opened and/or closed such that the separated components of a composition may be dispensed together and/or segregated, respectively, when desired. In one aspect, the switching assembly may incorporate a rotatable portion that may allow a user to control the open or closed state of the compartments. In another aspect, the switching assembly may incorporate a pull/push closable feature that may unplug/plug the outlets of the compartments. 
         [0020]    In another alternative embodiment, the compartments may include spatially segregated outlet ports that may substantially decrease the interaction of the components of a composition until an adequate amount of the components is dispensed such that the spatial segregation may be overcome to affect interaction and/or mixing of the components. 
         [0021]    In yet another embodiment, the tip may incorporate a means of closing and/or sealing the delivery outlet point such that a user may prevent substantially all of the composition from exiting the mixing tip, when, for example, in a pause during a procedure or using said composition for multiple procedures. 
         [0022]    In another exemplary embodiment, the multi-compartment device may include a double-barrel syringe body, a rotatable head, a mixing element, and a pre-mixing neck portion including two connecting channels. Each connecting channel extends from the outlet of each barrel and ends at a sealing surface located at the lower inner surface of the rotatable head. When the syringe is in a closed position, the sealing surface entirely blocks the discharge end of the connecting channel to prevent premature interaction between the components from the syringe barrels. In an open position, the sealing surface rotates away by slightly turning the rotatable head to enable the component from each barrel to move upwardly toward the mixing element. 
         [0023]    In other embodiments, the multi-compartment device may include a double-barrel syringe body, a mixing tip, a mixing and switching assembly including a mixing element integrated with a plug, and a pre-mixing neck portion including two connecting channels with tapered ends. The plug includes at least two tapered units which tightly fit with the tapered ends of the connecting channels to form a tight seal to prevent the component in each barrel from premature mixing with each other. The mixing tip may include a tip portion and a threaded portion, the former closely receives the mixing and switching assembly, and the later is adapted to attach to the pre-mixing neck portion by screwing onto the outer surface thereof, wherein at least portion of the threaded portion of the mixing tip engages with at least portion of the plug which is forced down to close the outlet of the barrel. An opened position may be achieved when a user makes an upward quarter or half turn of the mixing tip to disengage the plug, and when appropriate external force is applied to the components in the barrels, the disengaged mixing and switching assembly is accordingly lifted away from the closed position to allow the component in each barrel to move toward the tip portion of the mixing tip where the components can be mixed in the manner as stated previously. The device can be resealed simply by screwing down the mixing tip again. In another aspect, the mixing element is not integrated with the plug. 
         [0024]    In still another aspect, the tip itself may serve as a plug. For example, a hemispheric channel blocker is located within the mixing tip, wherein the outer surface of the hemispheric channel blocker is adapted to block each connecting channel. When the mixing tip is screwed all the way down to close the syringe, the outer surface of the hemispheric channel blocker substantially blocks each connecting channel to prevent the components in the barrels from leaking or premature mixing with the other component. The syringe can be opened when a user makes an upward quarter or half turn of the mixing tip to move the outer surface of the channel blocker away from the connecting channels, such that when appropriate force is applied from the double-plunger assembly to the components in the barrels, the component in each barrel is allowed to move toward the tip portion of the mixing tip where the components are mixed to form an admixture for dispensing. The syringe in the present embodiment can be resealed simply by screwing down the mixing tip again. 
         [0025]    In one embodiment of the invention, the multi-compartment device may include a syringe body, which may include a double-barrel assembly having juxtaposed first and second barrels having a common length and a generally cylindrical bore. Each barrel is bounded at a discharge end by first and second shoulders, respectively, with each shoulder having a generally planar surface. The surfaces are coplanar and contiguous. A generally cylindrical neck extends from and is substantially symmetrically disposed between the shoulders. The neck includes first and second outlet passages. Each barrel at its opposite (plunger) end closely receives a piston within its bore. An arcuately-shaped finger-grip circumscribes the contiguous plunger ends of the barrels. The syringe body further includes a double-plunger assembly having juxtaposed first and second plungers of a common length. Each plunger extends at a proximal end in an end-piece rigidly attached to one of the pistons, and is rigidly attached at a distal end to a thumb-rest common to the plungers. 
         [0026]    In one embodiment, the diameters or sizes of the barrels or compartments may be the same, for example, in a 1:1 ratio. In another embodiment, the diameters or sizes of the barrels or compartments may be different, for example, in a ratio of 1:2 to 1:5. 
         [0027]    In one aspect, the syringe includes a pre-applied dispensing and/or mixing tip that may be integrally or detachably attached to the syringe body. The dispensing and/or mixing tip may be generally conical in shape and may have an inlet end (Proximal), a discharge end (Distal) and a bore therethrough. The bore may be generally cylindrical at the inlet end and may extend in a conically tapered fashion toward the discharge end (Distal). The cylindrical bore portion may be determined by a circumferential surface that may be adapted to closely receive the body neck. 
         [0028]    For a mixing tip, a static mixing element may be closely received and wedged within the bore of the tapered portion of the tip. The mixing tip may include at the inlet end a second mating assembly having opposed generally planar, arcuate first and second locking tabs of a common predetermined thickness slightly less than the distance between the rib locking faces of the first mating assembly and the neighboring shoulder. Each tab may have at least one edge beveled at a common predetermined angle. The tabs may be symmetrically disposed with respect to the cylindrical bore portion. The bore circumferential surface may include diametrically opposed first and second detent recesses and first and second ramps which may be contiguous at a proximal end, respectively, to the recesses. 
         [0029]    In one embodiment, the static mixer may have a four section mixing element. Alternatively, a five section static mixing element may be received and wedged within the bore tapered portion. It has been observed that the use of a five section static mixing element may provide up to approximately 50% better mixing than the four section static mixing element. Those skilled in the art will appreciate that additional sections of the static mixing element may provide further enhanced mixing and may therefore be desirable. 
         [0030]    In one aspect, each section of the static mixing element may include a single turn screw, intertwined blades, baffles and/or fins. Each screw may be clocked, i.e., configured so as to be right or left handed, opposite that of each adjacent screw and may be oriented, with respect to the leading and trailing edges thereof, at 90° with respect to each adjacent screw. Thus, as the two viscous materials flow from one screw to the next screw, the viscous materials may be split into two portions, such that it may effect the desired mixing thereof. The screws may be disposed upon a common shaft. The screws may taper in size such that the viscous materials may flow through successively smaller screws as the viscous materials are dispensed. 
         [0031]    In one aspect, the screws may be disposed upon a common shaft. In another aspect, the screws may include at least one tapered section such that the materials may flow through the at least one tapered section as the materials are dispensed. 
         [0032]    In some embodiments, the dispensing and/or mixing tip may be integrally formed onto the body of the syringe. 
         [0033]    In other embodiments, the dispensing and/or mixing tip may be separate and/or detachable from the body of the syringe. 
         [0034]    In an exemplary aspect, the mixing tip may be formed from a single molded piece. In one embodiment, the mixing tip piece may include multiple sections that may form, when viewed from its end, sectors of a full circle and may, when assembled properly, form a fully cylindrical, conical and/or other appropriately shaped tip that may have a substantially hollow interior. The interior surface of the mixing tip may also have a plurality of baffles, fins and/or other formations that may be adapted to facilitate the mixing tip&#39;s static mixing function when the tip is properly assembled. The baffles, fins and/or other formations may be formed onto the surfaces of the sections of the unassembled mixing tip during manufacture, such that the formations may be distributed in a desired fashion and/or pattern on the surfaces of the mixing tip sections. 
         [0035]    In another aspect, the tip may include a dynamic mixing element. In one embodiment, the dynamic mixing element may include movable mixing formations to facilitate mixing of the components of a composition. 
         [0036]    The present invention also relates to a multi-chambered device for storing and dispensing the material components of an admixture, including a housing having at least two chambers each having an outlet and an inlet with full fluid communication between the inlet and the outlet, and a dispensing tip adapted for attaching to the housing about the outlets of the chambers, said tip comprising an inlet, an outlet and a generally axial bore comprising a mixing and switching assembly disposed therein. The device may also include a pre-mixing neck portion having at least two connecting channels with full fluid communication between the housing and the dispensing tip when the device is in its open position. In one embodiment, each connecting channel is extended from the outlet of each chamber to a discharge end of the pre-mixing neck portion. 
         [0037]    In one embodiment, the mixing and switching assembly may include a plug and a static or a dynamic mixing element for mixing at least two materials dispensed from the chambers. 
         [0038]    In one aspect of any of the above embodiments, the plug may include at least two tapered units. According to one embodiment, the mixing element may be integrated with the plug. In another aspect, the tapered units of the plug substantially block the connecting channels. In a further aspect, at least a portion of the threads of the dispensing tip engage with the plug, such that when the tip may be screwed toward the closed position, the plug is forced down to close the discharge end of the pre-mixing neck portion. In yet another aspect, the dispensing tip may disengage with the plug when the tip is screwed toward the open position. 
         [0039]    In another embodiment, the dispensing tip may include threads to rotatably control an open or closed position of the device. 
         [0040]    In a further embodiment, the mixing element may be disposed separately with the plug and may include a disc and at least two legs extended therefrom. 
         [0041]    In one aspect of any of the embodiments above, the legs of the plug may substantially block the connecting channels. In another aspect, the at least portion of the threads of the dispensing tip may engage with the disc of the plug, such that when the tip is screwed toward the closed position, the plug is forced down to close the discharge end of the pre-mixing neck portion. At the same time, the dispensing tip may disengage with the disc when the tip is screwed toward the open position. 
         [0042]    In still another embodiment, a mixing element may be disposed separately with the plug which is integrated with at least portion of the dispensing tip. 
         [0043]    In one aspect of any of the embodiments above, the plug may be located within the dispensing tip. At least portion of the threads of the dispensing tip may engage with corresponding threads of the neck portion, such that when the tip is screwed toward the closed position, the plug is accordingly moved down toward the connecting channels. In another aspect, an outer surface of the plug may substantially block the connecting channels. The outer surface of the plug may be moved away when the tip is screwed toward the open position. 
         [0044]    The present invention further relates to a dispensing and mixing tip. The tip has a body having multiple sections and two free edges, each of said multiple sections having an inner surface and an outer surface; and multiple formations extending from the inner surfaces of the multiple sections. The two free edges of the multiple sections may be joined to form a conduit and the multiple formations may be arranged to form a mixing system within the conduit of the tip. The multiple formations may be staggered, angled or aligned. The body may also be of unitary construction. 
         [0045]    In one embodiment, the formations of the dispensing and mixing tip may include fins, blades, baffles or combinations thereof. 
         [0046]    In another embodiment, the mixing system may include a static or a dynamic element. 
         [0047]    In a further embodiment, the body may be adapted for rotation within an external housing. 
         [0048]    Any of the above embodiments and aspects of the invention may be applicable to all other inventions, embodiments and aspects. 
         [0049]    The present invention together with the above and other advantages may best be understood from the following detailed description of the embodiments of the invention illustrated in the drawings below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0050]      FIG. 1  is an exploded perspective view of a double-barreled syringe according to the invention, including a double-plunger assembly, two pistons, a double-barrel assembly, a static mixing element, and an applied dispensing and/or mixing tip; 
           [0051]      FIG. 2  is a discharge end perspective view of the  FIG. 1  double-barrel assembly, including two shoulders, a neck with two outlet passages, and a mating assembly with two diametrically opposed detents and two symmetrically disposed locking ribs for engaging and interlocking with the dispensing and/or mixing tip; 
           [0052]      FIG. 3  is an inlet end perspective view of the  FIG. 1  dispensing and/or mixing tip, including a mating assembly, having two locking tabs, which engages and interlocks with the  FIG. 2  mating assembly; 
           [0053]      FIG. 4  is a partial perspective view of a double-barreled syringe with a pre-applied dispensing and mixing tip and a combined cap and pull tab in an exemplary embodiment of the invention; 
           [0054]      FIG. 4A  is a partial cross-sectional view of the double-barreled syringe assembly of  FIG. 4 ; 
           [0055]      FIG. 4B  illustrates the usage of a break point with the double-barreled syringe assembly of  FIG. 4 ; 
           [0056]      FIG. 4C  illustrates capping the double-barreled syringe assembly of  FIG. 4 ; 
           [0057]      FIG. 4D  is a partial exploded cross-sectional view of the double-barreled syringe assembly of  FIG. 4 ; 
           [0058]      FIG. 5  is partial cross-sectional perspective view of a double-barreled syringe assembly with an inert material; 
           [0059]      FIG. 5A  is partial cross-sectional exploded view of a double-barreled syringe assembly with an inert material; 
           [0060]      FIG. 5B  is partial cross-sectional exploded view of a double-barreled syringe assembly with a combined cap and pulling tab, and an inert material. 
           [0061]      FIG. 6  is a partial cross-sectional perspective view of a double-barreled syringe assembly with a seal and seal breakers; 
           [0062]      FIG. 6A  is a perspective view of a seal breaker of  FIG. 6 ; 
           [0063]      FIG. 7  is an exploded perspective view of a double-barreled syringe manual control system; 
           [0064]      FIG. 7A  is a top view of the double-barreled syringe manual control system of  FIG. 7  in the closed alignment; 
           [0065]      FIG. 7B  is a top view of the syringe manual control system of  FIG. 7  in the open alignment; 
           [0066]      FIG. 8  is a partial cross-sectional view of a double-barreled syringe assembly with a stopper system in the open alignment; 
           [0067]      FIG. 8A  is a partial cross-sectional view of a double-barreled syringe assembly with a stopper system in the closed alignment; 
           [0068]      FIG. 8B  is a perspective view of a stopper cylinder of  FIGS. 8 and 8A ; 
           [0069]      FIG. 9  is a perspective view of a mixing and dispensing tip with integral static mixing formations; 
           [0070]      FIG. 9A  is a axial view of an assembled mixing and dispensing tip with integral static mixing formations of  FIG. 9 ; 
           [0071]      FIG. 9B  is a partial see-through perspective view of a mixing and dispensing tip within an external form; 
           [0072]      FIG. 9C  is a perspective view of a mixing and dispensing tip with integral static mixing formations; 
           [0073]      FIG. 9D  is a partial see-through perspective view of an assembled mixing and dispensing tip with integral static mixing formations of  FIG. 9C ; 
           [0074]      FIG. 10  is a perspective view of a double-barrel syringe with a rotatable head. 
           [0075]      FIG. 10A  is a cross-sectional perspective view of a double-barrel syringe with a rotatable head. 
           [0076]      FIG. 10B  is a partial cross-sectional perspective view of a double-barrel syringe focusing on the rotatable head. 
           [0077]      FIG. 10C  is a perspective view of the double-barrel syringe with a rotatable head in a closed position. 
           [0078]      FIG. 10D  is a perspective view of the double-barrel syringe with a rotatable head in an open position. 
           [0079]      FIG. 10E  is a perspective view of the rotatable head with integral static mixing formations. 
           [0080]      FIG. 10F  is a perspective view of the rotatable head with integral static mixing formations of another embodiment. 
           [0081]      FIG. 10G  is a perspective view of the rotatable head with integral static mixing formations forming flow channels. 
           [0082]      FIG. 11  is a perspective view of a double-barrel syringe including a rotatable mixing tip. 
           [0083]      FIG. 11A  is an exploded perspective view of the syringe in  FIG. 11 , including a mixing element with an integrated plug. 
           [0084]      FIG. 11B  is a partial cross-sectional perspective view of the syringe in  FIG. 11  when the syringe is in its closed position. 
           [0085]      FIG. 12  is a perspective view of another double-barrel syringe including a rotatable mixing tip. 
           [0086]      FIG. 12A  is an exploded perspective view of the syringe in  FIG. 12 , including a mixing element with a separated plug. 
           [0087]      FIG. 12B  is a partial cross-sectional perspective view of the syringe in  FIG. 12  when the syringe is in its closed position. 
           [0088]      FIG. 13  is a perspective view of another double-barrel syringe including a rotatable mixing tip. 
           [0089]      FIG. 13A  is an exploded perspective view of the syringe in  FIG. 13 , including a mixing tip, a mixing element and a syringe barrel. 
           [0090]      FIG. 13B  is a partial cross-sectional perspective view of the syringe in  FIG. 13A . 
           [0091]      FIG. 13C  is a partial cross-sectional perspective view of the syringe when the syringe is in its closed position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0092]    While the present invention is open to various modifications and alternative constructions, the embodiments shown in the drawings will be described herein in detail. It is to be understood, however, there is no intention to limit the invention to the particular form disclosed. On the contrary, it is intended that the invention cover all modifications, equivalences and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims. 
         [0093]    The invention relates to an article of manufacture which is primarily intended for storing and dispensing gels which are components of an admixture that may need to be kept separate until the admixture is formed. However, the invention is not limited to particular types of material to be stored and dispensed, and can be used for storing and dispensing any material that can be placed within a syringe barrel and effectively admixed by a static or dynamic mixing tip. 
         [0094]    Where used herein, the word “attached” means that the two parts referred to (e.g., a locking rib and a shoulder or a plunger end-piece and a piston) are either molded in a single piece, are glued, slip onto one another, friction fit or force-fitted together, and may or may not be easily separated after being joined together. However, other forms of attachment may be suitable, consistent with simplicity of manufacture and reliability of operation. Where used herein, the word “connected” means that the two parts referred to (viz., the two mating assemblies) can be easily separated after being joined together in an interlocking combination. 
         [0095]    Referring to  FIGS. 1 and 2 , a syringe body  10  may include a double-barrel assembly  12  that may have juxtaposed first and second generally cylindrical barrels  14 L,  14 R which may have a common length and a generally cylindrical bore  16 L,  16 R, respectively, that may be of a common diameter that may determine storage compartments  15 L (not shown),  15 R (not shown). Barrels  14 L,  14 R may be bounded at a first (discharge) end  18 L,  18 R, respectively, by first and second shoulders  20 L,  20 R, respectively. The shoulders may have generally planar surfaces  21 L,  21 R, respectively, which may be coplanar and contiguous. A generally cylindrical neck  22  may extend from and may be, for example, substantially symmetrically disposed between the shoulders. As shown in  FIG. 2 , neck  22  may include first and second outlet passages  24 L,  24 R, which may be divided by a partition  26 . Barrels  14 L,  14 R may be open at an opposite (plunger) end  28 L,  28 R, respectively, which may closely receive pistons  30 L,  30 R, respectively. Barrel ends  28 L,  28 R may be circumscribed by and rigidly attached to an arcuately-shaped finger-grip  32 . 
         [0096]    The syringe body  10  may further include a double-plunger assembly  36  that may have juxtaposed generally cylindrical first and second plungers  38 L,  38 R of a common length. Each plunger may extend at an end  40 L,  40 R proximal to a piston in an end-piece  42 L,  42 R that may be rigidly attached to the piston  30 L,  30 R, respectively. The plungers may be attached at their distal end  44 L,  44 R to, for example, a disc-shaped thumb-rest  46  such that when the thumb-rest is depressed the plungers may move forward in tandem, and the attached pistons may move in tandem within the barrels. In other embodiments, the plungers may be separate. 
         [0097]    Still referring to  FIG. 2 , syringe body  10  may further include a first mating assembly  50  that may have diametrically opposed first and second detents  52 ,  54  that may extend outwardly from neck  22 , and opposed first and second locking ribs  56 L,  56 R that may be, for example, substantially symmetrically disposed with respect to neck  22 . Ribs  56 L,  56 R may each have a first (stand-off) portion  57 L,  57 R, respectively, which may be generally parallel to the shoulders  20 L,  20 R, respectively, and generally orthogonal to a second (bracket) portion  58 L,  58 R (not shown), respectively, which may be rigidly attached, respectively, to shoulders  20 L,  20 R. Rib stand-off portions  57 L,  57 R may each have two generally planar locking faces  59 L,  60 L, and  59 R (not shown),  60 R (not shown), respectively, which may be, for example, generally parallel to and at a generally common distance from the neighboring shoulder surface  21 L,  21 R, respectively, thus determining substantially symmetrical recesses  62 L,  62 R (not shown), respectively. 
         [0098]    In some embodiments, double-barrel assembly  12 , including neck  22 , and mating assembly  50  may be fabricated as a unit from a suitable material, such as, for example, polymeric materials that may be biodegradable, compostable, recyclable, non biodegradable or non-recyclable and may include polypropylene, polyethylene, polycarbonate, polystyrene, polyacrylic polymers, polylactic acid, and/or any other suitable material. The double-barrel assembly  12  may be manufactured by a variety of methods such as, for example, various molding methods that may include injection-molding. Some materials may be colored to protect the constituents from exposure to UV and or light exposure. Also in addition, those skilled in the art may fabricate the unit from a material that may protect the constituents from drying out and from degrading due to exposure to certain elements in the air. 
         [0099]    Referring to  FIGS. 1 and 3 , the syringe body  10  may have disposed on it a pre-applied dispensing and/or mixing tip  70 . The tip  70  may be attached to the syringe  10  at the time of manufacture and/or any time prior to the delivery to the customer. This may decrease the chance of loss and any subsequent loss of function and/or usability of components, decrease the complexity of usage and in general provide for an increase in convenience to the customer. The pre-applied tip  70  may be attached to the syringe  10 ′ by permanent, integral and/or detachable means, and may include an inlet end  72  and a discharge end  74  and a bore  76  therethrough. As best shown in  FIG. 3 , bore  76  may have a generally cylindrical portion  78  proximate to inlet end  72  and may extend in a conically tapered portion  80  (not shown) toward the discharge end  74 . Cylindrical bore portion  78  may be determined by a circumferential surface  78 S that may be adapted to closely receive the neck  22 . 
         [0100]    Still referring to  FIG. 3 , the inlet end  72  of tip  70  may include a second mating assembly  90  that may have, for example, opposed generally planar and/or arcuately-shaped first and second locking tabs  92 ,  94  of a common predetermined thickness that may be slightly less than the common width of recesses  62 L,  62 R. Tabs  92 ,  94  may be, for example, substantially symmetrically disposed with respect to cylindrical bore portion  78  and may have edges  93 A (not shown),  93 B (not shown) and  95 A,  95 B, respectively, which may each be beveled at an angle of about 8 degrees. Tabs  92 ,  94  may be rigidly attached, respectively, to structural ribs  98 ,  100  which may be, for example, disposed substantially symmetrically with respect to bore portion  78 , and may extend in generally oval-shaped collar portions  102 ,  104 , respectively. The two collar portions may partially circumscribe inlet end  72  and extend such that tab  92  may be rigidly attached at an interior edge  92 E (not shown) to collar portion  104 , and tab  94  may be rigidly attached at an interior edge  94 E to collar portion  102 . Surface  78 S may include substantially diametrically opposed first and second detent recesses  110 ,  112  and a plurality of corrugations  114 . 
         [0101]    In some embodiments, dispensing and/or mixing tip  70  and associated mating assembly  90  may be fabricated as a unit from a suitable material, including those suitable for the barrels or compartments mentioned above, for example. The tip  70  may be manufactured by a variety of methods such as, for example, various molding methods that may include injection-molding. 
         [0102]    A mixing element, for example a static mixing element  82  may be closely received and wedged within the tapered bore portion  80 . The static mixing element  82  may include a four section static mixing element in one embodiment. That is, the mixing element  82  may include four separate single turn screws. In another embodiment, the mixing element  82  may include a five section static mixing element. The mixing element  82  may be inserted in a random azimuthal orientation within bore portion  80  and so may not be disposed in a predetermined orientation with respect to partition  26  and outlet passages  24 L,  24 R when tip  70  is attached to double-barrel assembly  12 . 
         [0103]    Further examples of the mixing elements  82  may be found in U.S. Pat. Nos. 5,819,988, 6,065,645, 6,394,314, 6,564,972, 6,698,622, and 4,767,026, the contents of which are hereby incorporated by reference. 
         [0104]      FIG. 4  shows a partial perspective view of a double-barreled syringe  10 ′ with a pre-applied dispensing and/or mixing tip  70  in an exemplary embodiment of the invention. The double-barreled syringe  10 ′ may be substantially identical to the double-barreled syringe assembly  12  of  FIG. 1 . 
         [0105]    In an exemplary embodiment, the syringe  10 ′ with pre-applied tip  70  may include integral or detachable means of isolating and/or sealing the contents of the syringe barrels  14 R,  14 L prior to use and may provide additional means of allowing interaction between the contents and/or closing the syringe.  FIG. 4A  shows a partial cross-sectional view of the syringe  10 ′ with pre-applied dispensing and/or mixing tip  70  of  FIG. 4 . In one aspect, the pre-applied tip  70  may have disposed within a static mixing element  82  that may be substantially identical in form and function to the mixing element  82  as shown in  FIG. 1 . In one embodiment, the static mixing element  82  may have cap plugs  82 R,  82 L attached at the end proximal to the outlets  24 R,  24 L. The cap plugs  82 R,  82 L may substantially close and/or seal the outlets  24 R,  24 L, respectively and thus may substantially eliminate, minimize or prevent the release and/or interaction of the contents of the barrels  14 R,  14 L, respectively. Prior to use, the cap plugs  82 R,  82 L may be removed such that the contents of the barrels  14 R,  14 L may exit and may be dispensed and/or mixed. A pull shaft  83  may be attached to the static mixing element  82  at its end distal to the outlets  24 R,  24 L. The pull shaft  83  may extend beyond the end of the pre-applied tip  70  and may allow the user to effect the removal of the cap plugs  82 R,  82 L by means of pulling on the pull shaft  83  such that the static mixing element  82  and by virtue of its attachments, the cap plugs  82 R,  82 L may be shifted distally from the outlets  24 R,  24 L, thus opening them. 
         [0106]    Since additional objects in the flow path of the pre-applied tip  70  may restrict the exiting of a composition therefrom, it may be desirable to remove pull shaft  83  after utilizing it to remove cap plugs  82 R,  82 L. A break point  83   a  may be included between the pull shaft  83  and the static mixing element  82  such that a properly applied and/or exerted force may effect its failure or breakage such that the pull shaft  83  may be removed from the flow path of the pre-applied tip  70  while retaining the static mixing element  82 , if present, as shown in  FIG. 4B . In general, the properly applied and/or exerted force necessary to effect failure or breakage at the break point  83   a  may be greater than the force required to remove the cap plugs  82 R,  82 L from the outlets  24 R,  24 L. 
         [0107]    A mating formation  84  also may be included such that the pull shaft  83  may be attached to a handle and/or other component that may allow easier effecting of the pulling motion, such as the combined cap and pull tab  130 ′ shown in  FIGS. 4 and 4A . The combined cap and pull tab  130 ′ may include a mating formation  133  that may substantially couple it to the mating formation  84  of the pull shaft  83 . Thus, by pulling on the combined cap and pull tab  130 ′, the user may effect the removal of the cap plugs  82 R,  82 L as discussed above with greater ease. The combined cap and pull tab  130 ′ may also include features that may increase its grippability and/or its ease of handling, such as, for example, handle tabs  132 , as shown in  FIG. 4A . Other features, that may include, but are not limited to, textured gripping surfaces, pull bars that the users may hook their fingers around for better grip, and/or any other suitable features may be included. In general, the mating formations  84 ,  133  may maintain their interface up to and beyond the force required to remove the cap plugs  82 R,  82 L from outlets  24 R,  24 L as well as the force required to effect failure or breakage of breaking point  83   a.    
         [0108]    In an exemplary embodiment, the combined cap and pulling tab  130 ′ may also include a feature, for example, a formation that may allow it to substantially cap and/or close the pre-applied tip  70 . A hollow space  131  may be included, which may be adapted to fit snuggly and/or tightly over the end of the pre-applied tip  70  such that the combined cap and pulling tab  130 ′ may be placed onto the end of the pre-applied tip  70  to substantially close it, as illustrated in  FIG. 4C . 
         [0109]    In some embodiments, the syringe body  10 , tip  70 , static mixing element  82  and combined cap and pulling tab  130 ′ may be formed as separate elements that may be assembled prior to deliver to a customer, as illustrated with the partial exploded view in  FIG. 4D . 
         [0110]    In other embodiments, the above components may be integrally combined in various combinations including, but not limited to, the combined cap and pulling tab and the static mixing element and/or any other suitable combination. 
         [0111]    In some embodiments, the attachment of the tip may be accomplished by means of the previously discussed mating formations illustrated in  FIGS. 1-3 . In other embodiments, other attachment methods may be utilized, including, but not limited to, adhesive attachment, friction fit attachment, threaded screw in attachment, fusing (e.g. melting), and/or any other appropriate attachment method. 
         [0112]    In other aspects, after the cap plugs  82 R and  82 L are removed from the outlets  24 R and  24 L, the syringe may include further means of segregating the contents of the separate barrels before intended use. In one aspect, as illustrated in the partial cross-sectional view of  FIG. 5 , the barrels  14 R,  14 L of the syringe body  10  may be at least partially filled with inert material  502  at the end proximal to the tip  70 . The composition components  500 R,  500 L, which may be mixed to form an active admixture, may substantially fill the remainder of the internal space of the barrels  14 R,  14 L, respectively. The inert material  502  may substantially act as a barrier that may effect the substantial segregation of the composition components  500 R,  500 L and may be in direct contact with the components  500 R,  500 L, which may result in a layered effect within the barrels  14 R,  14 L, respectively. The inert material  502  may be removed to allow interaction of the components  500 R,  500 L to form an active admixture by means of applying a force onto the contents of the barrels  14 R,  14 L using the plungers  38 R,  38 L, respectively, in the manner discussed above. 
         [0113]    The inert material  502  may be any material that may act as a barrier against the composition components  500 R,  500 L. The inert material  502  may, for example, resist mixing, reacting and/or otherwise not interact with the components  500 R,  500 L and may be a gel or other high viscosity fluid, a deformable solid, a packed powder, and/or any other suitable material type. Examples of suitable materials may include, but are not limited to, saccharide polymer gels such as agar, agarose, pectin and alginate, protein polymer gels such as gelatin, silicone, oil, petroleum jelly, and cationic polymer gels such as polyvinylpyrrolidone, polyvinyl alcohol and cellulosic material such as hydroxypropyl cellulose. 
         [0114]    The presence of an inert material  502  may also aid in the use of the syringe  10  and the dispensing and/or mixing tip  70  by, for example, filling flow voids within the dispensing and/or mixing tip  70 , which may allow a greater proportion of the active composition to be dispensed rather than being wasted inside the tip. 
         [0115]    In some embodiments, at least a portion of the barrels  14 R,  14 L proximal to the tip  70  may be filled with an inert material  502 . In other embodiments, at least a portion of the interior of the tip  70  may also be filled with an inert material  502 . 
         [0116]    In still other embodiments, the inert material  502  may be spaced internally from the composition components  500 R,  500 L within the barrels  14 R,  14 L, respectively, by the space or gap  504 , as illustrated in the partial cross-sectional exploded view of  FIG. 5A . 
         [0117]    In another embodiment, as exemplified in  FIG. 5B , the tip may include a cap and a plug shape element adapted to be disposed inside the cap. A mixing element is attached and integral with the plug shape element, and maybe adapted for introducing the plug shape element into the barrel region of the syringe body. The pocket or hollow interiors of the barrel or barrels may have a corresponding feature for receiving the plug shape element so that the exit openings of the barrel or barrels may be closed by the plug shape element. The cap of the tip may also include, for example, threads adapted for attaching to the barrel or barrels by screwing onto the base thereof and a ledge for pushing the plug element on the mixing element onto the pocket or pockets of the barrel or barrels, closing the openings. The barrels  14 R,  14 L of the syringe body  10  may be at least partially filled with inert material  502  at the end proximal to the tip  70 . Once the user applies appropriate external force to break the pull shaft  83  (preferably at the breaking point  83 a) and effects the removal of the cap plugs  82 R and  82 L by pulling on the combined cap and pull tab  130 ′, the inert material  502  may be removed to allow interaction of the components  50 OR and  500 L to form an active admixture by means of applying a force onto the contents of the barrels  14 R and  14 L using the plungers  38 R,  38 L, respectively, in the manner previously discussed. 
         [0118]    In another embodiment, the tip may include a mixing element adapted to be disposed inside the tip and a separate plug element adapted for fitting into the exit opening end of the barrel or barrels. The plug element may be forced into place on the barrel or barrels by attachment of the tip. 
         [0119]    In another aspect, the features may include seals that may be forced and/or broken so as to allow the contents of a compartment to exit. 
         [0120]    In one embodiment, a seal, such as a foil seal, a wax paper seal or a polymeric film seal, may be introduced at the top of the barrel or barrels to seal off the content or contents. The seals may be adhesively coated for attachment to, for example, the top of the barrels. A formation, for example, a pointed formation, is adapted for breaking the seal may be introduced to the barrel or barrels before the barrel or barrels are filled with compositions. During use, the user may push on the plunger or plungers, driving the formation through the foil to open the barrel or barrels. 
         [0121]    In another embodiment, a removal seal which may be a foil seal, for example, may be introduced at the top of the barrel or barrels to seal off the content or contents, as exemplified in  FIG. 6 . The barrel or barrels may be modified to include a cap which may be attached to the barrel or barrels with a living hinge. The cap may include a mixing element and adapted for attaching onto the opening end of the barrel or barrels. When the seal is removed, the cap may be onto the barrel or barrels for use. 
         [0122]    In another aspect, the segregation of the composition components within the barrels of a syringe may be accomplished by introducing a seal over the outlet ports of the barrels, as exemplified in  FIGS. 6 and 6A . The seal may substantially close off the outlet ports of the barrels and may preserve the segregation of the composition components by substantially sealing the surfaces of the outlet ports and a dividing formation, such as a septum, as discussed previously. The syringe may also include features, for example, formations, that may allow the user to remove and/or break the seal. Such features may be included in any appropriate position and/or location in the syringe  10 ″ such that they may effect the removal and/or breakage of the seal  25 , including, but not limited to, inside the barrels and between the outlet ports and the tip and/or mixing element, in close proximity to the seal. 
         [0123]      FIG. 6  illustrates the use of a seal  25  over the outlet ports  24 R,  24 L of the barrels  14 R,  14 L of a syringe  10 ″. In embodiments with a pre-applied tip (not shown), the syringe  10 ″ may include features that may allow the user to remove and/or break the seal  25  without removing the tip to gain access to the seal  25 , as noted above. 
         [0124]    In an exemplary embodiment, the syringe  10 ″ may include substantially identical seal breakers  200 R,  200 L, which may be adapted to lie within the chambers of the barrels  14 R,  14 L, respectively. The seal breakers  200 R,  200 L may include formations that may allow them to both break the seal  25  when a correctly applied force is introduced and may also include formations that may allow them to utilize an applied force from the user. The paddle-like portions  202 R,  202 L of the seal breakers  200 R,  200 L, respectively, may be adapted to substantially lie perpendicular to the long axis of the barrels  14 R,  14 L and may substantially occupy a significant proportion of the cross-sectional area of the interior space of the barrels  14 R,  14 L such that when a force is applied by the user to the plungers (not shown), the force may be transmitted to the paddle-like portions  202 R,  202 L via the contents of the barrels  14 R,  14 L such that the seal breakers  200 R,  200 L may move towards the outlets  24 R,  24 L. 
         [0125]      FIG. 6A  shows a perspective view of a seal breaker  200 , which may be utilized in either barrel  14 R,  14 L of the syringe  10 ″ as  200 R or  200 L, respectively. The seal breakers  200 R,  200 L may further include seal piercing formations  204 R,  204 L, respectively that, when the seal breakers  200 R,  200 L are moved sufficiently toward the outlets  24 R,  24 L, the seal piercing formations  204 R,  204 L may substantially displace and/or break the seal  25 , which may allow the contents of the barrels  14 R,  14 L to exit through the outlets  24 R,  24 L. 
         [0126]    The formations  204 R,  204 L may include substantially pointed and/or sharp leading portions  205 R,  205 L that may allow them to effectively pierce the seal  25  when an appropriate force is applied, as illustrated. 
         [0127]    In some embodiments, the paddle-like portions  202 R,  202 L may be substantially solid formations that may occupy only a portion of the total cross-sectional area of the barrels  14 R,  14 L such that the contents of the barrels  14 R,  14 L may still flow past the paddle-like portions  202 R,  202 L at, for example, cut-out areas  203 R,  203 L, as illustrated. 
         [0128]    In other embodiments, the paddle-like portions  202 R,  202 L may include perforations and/or other features, for example, formations, that may allow the contents of the barrels  14 R,  14 L to flow more freely through and/or past the paddle-like portions  202 R,  202 L. 
         [0129]    In still another aspect, the syringe may include features, for example, formations, that may allow the outlets of the barrels to be substantially opened and closed multiple times during the course of use. The opening and closing of the outlets may be accomplished substantially with the tip pre-applied and remaining on the syringe. The syringe may include, for example, a system that may allow the user to manually open and close the outlets of the barrels by actuating a portion of the syringe. 
         [0130]    In an exemplary embodiment, as exemplified in  FIG. 7  the syringe manual control system  700  may include spatially separated outlet ports  712 R,  712 L on the end of the barrels  710  proximal to the tip. The top surface  711  of the end of the barrels  710  may include stop pair bars  714 ,  716 , which may lie substantially at  90  degree intervals about the center of the top surface  711  on the perpendicular axes A, B, where pair  716  may lie substantially adjacent to the outlets  712 R,  712 L on axis B such that the sides of the top surface  711  corresponding to the outlets  712 R,  712 L may be symmetrical with respect to axis A. The stop pair bars  714 ,  716  may be substantially perpendicular to the top surface  711  and may be taller than the outlet ports  712 R,  712 L. 
         [0131]    A switching disc  720  may be included and may provide the open and closed states of the outlets  712 R,  712 L. The switching disc  720  may include apertures  722 R,  722 L which may, in one alignment, provide clear openings to the outlets  712 R,  712 L below. The switching disc  720  may further include a sealing surface  723  on the side that faces the outlets  712 R,  712 L. The sealing surface  723 , when in contact with the outlets  712 R,  712 L, may serve to substantially seal and/or block the outlets  712 R,  712 L such that the contents of the barrels of the syringe may be substantially contained and segregated. The sealing surface  723  may also provide a frictional and/or other holding force that may substantially limit free rotation of the switching disc  720  without the application of force by the user. 
         [0132]    The switching disc  720  may also include stop pair bars  726 , which may extend from the edge of the switching disc  720  in a direction substantially perpendicular to the radial axis of the switching disc  720 . The stop pair bars  726  may lie substantially opposite each other with approximately  180  degree spacing about the center of the switching disc  720  and may be slightly offset from the symmetric axis B. 
         [0133]    An axial shaft  730  may also be included and may interact with the switching disc  720  and the top surface  711  of the barrels. Axial holes  718 ,  728  may be included in the top surface  711  and switching disc  720 , respectively, to accommodate the axial shaft  730 . The axial shaft  730  may, for example, in some embodiments, be integral to the static mixing element and may substantially extend beyond the tip (not shown) such that the shaft  730  may be accessible to the user without removal of the tip. The axial shaft  730  may further include interfacing formations  731 ,  732  that may interface with corresponding formations  724  of switching disc  720 . The interface between formations  731 ,  732  and  724  may substantially lock the switching disc  720  and the axial shaft  730  together, such that rotation of the axial shaft  730  may affect a substantially identical rotation of the switching disc  720 . 
         [0134]    When assembled, the switching disc  720  may lie in substantially two alignments with the top surface  711 , closed, as shown in the top view of  FIG. 7A , and open, as shown in the top view of  FIG. 7B . In the closed configuration of  FIG. 7A , the switching disc  720  may be rotated such that the apertures  722 R,  722 L are  90  degrees misaligned from the outlets  712 R,  712 L (obscured by the switching disc  720 ). The stop pair bars  726  may prevent further rotation in the counterclockwise direction by stopping against the stop pair bars  716  of the top surface  711 . The alignment may be changed to the open alignment, as shown in  FIG. 7B , by rotating the switching disc  720 , for example, in the clockwise direction. 
         [0135]    In the open configuration, the apertures  722 R,  722 L may align with the outlets  712 R,  712 L such that the contents of the barrels may exit through the openings (as indicated by the shaded regions). The stop pair bars  726  and the axial shaft  730  may be utilized by the user to effect a change in the alignment of the switching disc  720  by rotation in a given direction. 
         [0136]    In another embodiment, the directional orientations of the various components may be reversed such that clockwise rotation of the switching disc  720  closes the outlets  712 R,  712 L and counterclockwise rotation opens them. 
         [0137]    In some embodiments, the apertures  722 R,  722 L may be substantially the same size and shape as the outlets  712 R,  712 L. In other embodiments, apertures  722 R,  722 L may be of a different size and shape than the outlets  712 R,  712 L. 
         [0138]    In other embodiments, the outlets  712 R,  712 L may be flush with the surface of top surface  711  and the switching disc  720  may lie directly on the top surface  711 . The switching disc  720  may also include formations that may lock it and/or otherwise fix it to the top surface  711  with respect to vertical and/or horizontal movement such that the switching disc  720  may still rotate freely about the central axis. 
         [0139]    In still other embodiments, the components of the system  700  may be of any shape and/or size that may effect the desired operation of the system  700 . 
         [0140]    In yet other embodiments, the outlets  712 R,  712 L may be adjacent in a unified column, such as in the syringes described previously. In such embodiments, the portion of the syringe  710  may be an adapter that may be included such that the outlets  712 R,  712 L may be spatially separated such that the resultant top surface may appear as shown in  FIGS. 7 ,  7 A and  7 B. 
         [0141]    In another exemplary embodiment, the syringe may include a stopper system that may serve to control the open and closed states of the outlets of the barrels.  FIG. 8  is a partial cross-sectional view of a double-barreled syringe system  800  with a pre-applied tip  870 . In one embodiment, the tip  870  may be permanently attached or integrally formed with the syringe. In another embodiment, the tip  870  may be detachable. The syringe system  800  may include barrels  812 R,  812 L with outlets  824 R,  824 L, respectively. The pre-applied tip  870  may include within it a static mixing element  883 , which may operate in a manner similar to the static mixing elements discussed above. 
         [0142]    The stop pair bars  726  may prevent further rotation in the clockwise direction by stopping against the stop pair bars  714  of the top surface  711 . The alignment may be changed to the closed alignment, as shown in  FIG. 7A , by rotating the switching disc  720  in the counterclockwise direction. 
         [0143]    The syringe system  800  may also include a stopper system  830  that may be adapted to substantially open and close the outlets  824 R,  824 L of the barrels  812 R,  812 L. The stopper system  830  may include a cylinder  834 , which is illustrated in  FIG. 8B , with perpendicular bore  836  that may pass through the cylinder  834  and may define two openings on opposite sides of the surface of the cylinder  835 . The bore  836 , when in the open alignment, as illustrated in  FIG. 8 , may serve as an opening to the outlets  824 R,  824 L and may allow the contents of the barrels  812 R,  812 L to exit through the outlets  824 R,  824 L to the tip  870  and static mixing element  883 . The cylinder  834  of the stopper system  830  may be rotated about its axis by actuating handle  832 . An adjustment nut  838  may also be included to allow tightening and/or loosening of the rotation of the cylinder  834 . A gasket  837  may provide cushioning of the nut  838  against the housing of the stopper system  830  and may aid in maintaining the tightness of the adjustment to the cylinder  834 . 
         [0144]    The handle  832  may be rotated from the open alignment by rotation in either the clockwise or counterclockwise direction to yield a closed alignment, an example of which is illustrated in  FIG. 8A . The surface  835  of the cylinder  834  may be contoured in a manner corresponding to a curvature and/or other contour present on the outlets  824 R,  824 L of the barrels  812 R,  812 L. The corresponding contours may assure a tight seal between the surface  835  and the outlets  824 R,  824 L when in a closed alignment. 
         [0145]    The components of the stopper system  830 , in particular the cylinder surface  835  and the corresponding surfaces on the other components may be manufactured from and/or coated with a material that may be conducive to allowing free rotation of the components while still allowing for a tight and/or sealing fit at the outlets  824 R,  824 L. Examples of appropriate materials include, but are not limited to, fluoropolymers such as polytetrafluoroethylne (PTFE or Teflon), fluorinated-ethylene-propylene (FEP) and perfluoroalkoxy polymer resin (PFA), lubricants such as silicone grease, petroleum-based products such as oil, and/or any other appropriate material. The materials utilized in the stopper system may also be, in general, resistant to any chemicals present in the compositions of the contents of the barrels  812 R,  812 L. 
         [0146]    In another exemplary embodiment, a syringe may include a rotatable head that may serve to control the open and closed states of the outlets of the barrels. As shown in  FIG. 10 and 10A , the syringe  1000  may include a syringe barrel  1010 , a mixing element  1020  and a rotatable head  1030 . The syringe barrel  1010  may include a double-barrel assembly  1012  that may have juxtaposed first and second generally cylindrical barrels  1014 L,  1014 R, which may have a common length and a generally cylindrical bore  1016 L,  1016 R, respectively. The syringe barrel  1010  may further include a double-plunger assembly  1036  that may have juxtaposed generally cylindrical first and second plungers  1038 L,  1038 R of a common length. 
         [0147]    As can be shown in  FIGS. 10A and 10B , a pre-mixing neck portion  1023  may have juxtaposed first and second generally cylindrical connecting channels  1024 L,  1024 R, respectively. The connecting channels  1024 L,  1024 R are L-shaped, extending from outlets of the cylindrical barrels  1014 L,  1014 R, respectively, and ending at sealing surfaces  1039 L,  1039 R, respectively, of the rotatable head  1030 . The sealing surfaces  1039 L,  1039 R are located at lower inner surfaces of the rotatable head  1030  and adapted to tightly seal discharge ends  1029 L,  1029 R of the connecting channels  1024 L,  1024 R, respectively, to prevent any premature interaction of the components in the barrels before mixing with each other. 
         [0148]    Still referring to  FIGS. 10A and 10B , the mixing element  1020  extends from a top surface  1041  of a base  1040 , and at least portion of the bottom surface  1041 ′ of the base  1040  forms portion of the inner surfaces of the connecting channels  1024 L,  1024 R, respectively. The L-shaped connecting channels  1024 L and  1024 R are located underneath the base  1040 . 
         [0149]    The mixing element  1020 , the base  1040  and at least portion of the pre-mixing neck portion  1023  are encircled by the rotatable head  1030  which includes, for example, threads  1031  (not shown) adapted to attach to the pre-mixing neck portion  1023  by screwing onto corresponding threads  1031 ′ (not shown) on the outer surface of the pre-mixing neck portion  1023  to adjust relative position between the discharge ends ( 1029 L,  1029 R) of the connecting channels ( 1024 L,  1024 R) and the sealing surfaces ( 1039 L,  1039 R). The rotatable head  1030  has a substantially hollow interior. In one embodiment, the rotatable head  1030  may form, when assembled properly, a tip portion  1032 , an enlarged middle portion  1033  and a thread portion  1034 . 
         [0150]    Referring to  FIG. 10C  with respect to a closed position according to the embodiment, the connecting channels  1024 L,  1024 R, respectively, are sealed when the sealing surfaces  1039 L and  1039 R substantially entirely block the outlets of the connecting channels  1024 L,  1024 R, respectively. The seal is sufficiently tight that any premature interaction of components from barrels  1014 L,  1014 R (not shown), may be minimized or prevented. In addition, those skilled in the art may furthermore make either interface sealing surface and or the threads that seal below the sealing surface from a flexible sealing material in appropriate durometer or hardness, such as silicon, thermosetting rubber, polypropylene, high density polyethelene, polyurethane, thermoplastic elastomer such as synthetic rubber like Kraton polymers, polyvinyl chloride, thermoplastic silicon vulcanite, or melt processable rubber to furthermore aid in the sealing. 
         [0151]    As can be seen in  FIG. 10D , the relative position between the sealing surfaces ( 1039 L,  1039 R) and the discharge ends ( 1029 L,  1029 R) of the connecting channels ( 1024 L,  1024 R) may be changed by twisting the rotatable head  1030 . Once the sealing surfaces  1039 L and  1039 R are moved away from the discharge ends  1029 L and  1029 R, the components in the barrels  1014 L,  1014 R (not shown), are allowed to move to the tip portion  1032  to form an admixture for dispensing. 
         [0152]    For example, when the sealing surfaces ( 1039 L,  1039 R) are removed, the component in each barrel moves forward separately from each connecting channel to at least portion of the inner surface of the rotatable head  1030  before reaching the mixing element  1020 , which may be closely received and wedged within the bore of the tapered portion of the rotatable head  1030 . The components are mixed in the tip portion  1032  in the manner as previously discussed. 
         [0153]    In some embodiments, the attachment of the rotatable head  1030  may be accomplished by means of clamping two identical halves to encircle the mixing element  1020 , the base  1040  and at least portion of the pre-mixing neck portion  1023 . In other embodiments, other attachment methods may be utilized, including, but not limited to, adhesive attachment, friction fit attachment, fusing (e.g. melting), and/or any other appropriate attachment method. 
         [0154]    In some embodiments, the rotatable head  1030  may include a cap  1050  as shown in  FIG. 10 , which may also include, for example, threads (not shown) adapted for attaching to the tip portion  1032  of the rotatable head  1030  by screwing onto the outer surface of the upper tip portion  1032 . 
         [0155]      FIGS. 11 and 11A  illustrates another exemplary embodiment of the syringe having a rotatable head. The syringe  1100  may include a syringe barrel  1110 , a mixing and switching assembly  1120 , and a rotatable mixing tip  1130 . The syringe barrel  1110  may include a double-barrel assembly  1112  that may have juxtaposed first and second generally cylindrical barrels  1114 L,  1114 R, which may have a common length and a generally cylindrical bore  1116 L,  1116 R, respectively. The syringe  1100  may further include a double-plunger assembly  1136  that may have juxtaposed generally cylindrical first and second plungers  1138 L,  1138 R of a common length. 
         [0156]    As can be seen in  FIG. 11A , a pre-mixing neck portion  1123  may have juxtaposed first and second connecting channels  1124 L,  1124 R, respectively. The tapered connecting channels extend from the outlets of the cylindrical barrels  1114 L,  1114 R, respectively, to the discharge end of the neck portion  1123 . The connecting channels ( 1124 L,  1124 R) may be spaced by a tapered protrusion  1125  adapted to securely hold the mixing and switching assembly  1120 . 
         [0157]    The mixing and switching assembly  1120  may include a mixing element  1121  and a plug  1122 , wherein the mixing element  1121  and the plug  1122  are assembled together and the mixing element  1121  extends from the top surface of the plug  1122 . The plug  1122  includes a right tapered unit  1126 R and a left tapered unit  1126 L, which are separated by a tapered vacancy  1127 . Each tapered unit may include a plurality of fins  1128 , arranged substantially in parallel, located thereat. The size and shape of taper units ( 1126 L,  1126 R) is designed to tightly fit the corresponding connecting channels  1124 L,  1124 R, respectively. When the mixing and switching assembly  1120  is pushed down and the pinnacle of the tapered protrusion  1125  reaches the tapered end of the tapered vacancy  1127 , the left and right tapered units  1126 L,  1126 R, substantially block the connecting channels  1124 L,  1124 R, respectively, and a tight seal of each connecting channel is formed to prevent the component in each barrel from prematurely mixing with each other. 
         [0158]    Referring to  FIGS. 11A and 11B , the mixing tip  1130  may include a tip portion  1131  and a thread portion  1132 . The mixing element  1121  is closely received and wedged within the bore of the tapered tip portion  1131 . The thread portion  1132  is adapted to attach to the pre-mixing neck portion  1123  by screwing onto portion of the outer surface thereof to control the position of the mixing and switching assembly  1120 . 
         [0159]    For example, when the mixing tip  1130  is screwed all the way down on the neck portion  1123 , the syringe is at its closed position, and the upper portion of the thread in the thread portion  1132  engages with the upper portion fins of the tapered units to force the plug down to close the outlets of the barrels, as shown in  FIG. 11B . An opened position may be achieved when a user makes an upward, for example, quarter or half turn of the mixing tip  1130  to disengage the mixing and switching assembly  1120 . In other words, the mixing and switching assembly  1120  is freely suspended within the mixing tip  1130  after an upward quarter or half turn of the mixing tip  1130 . Thus, when appropriate force is applied from the double-plunger assembly  1136  to the components in the barrels, the disengaged mixing and switching assembly  1120  is accordingly lifted away from the closed position to allow the component in each barrel to move toward the tip portion of the mixing tip  1130  for form an admixture for dispensing. The syringe in the present embodiment can be resealed simply by screwing down the mixing tip  1130  again. 
         [0160]    In some aspects, the plug and the mixing element are not integrated together. As shown in  FIGS. 12 and 12A , the syringe  1200  may include a syringe barrel  1210 , a mixing and switching assembly  1220  including a plug  1221  and a mixing element  1222 , and a rotatable mixing tip  1230 . Likewise, the syringe barrel  1210  may include, fro example, a double-barrel assembly  1212  that may have juxtaposed first and second generally cylindrical barrels  1214 L,  1214 R, respectively, which may have a common length and a generally cylindrical bore  1216 L,  1216 R, respectively. The syringe barrel  1210  may further include, for example, a double-plunger assembly  1236  that may have juxtaposed generally cylindrical first and second plungers  1238 L,  1238 R of a common length. 
         [0161]    Referring to  FIG. 12A  and  FIG. 12B , a pre-mixing neck portion  1223  may have juxtaposed first and second connecting channels  1224 L,  1224 R, respectively. Each connecting channel extends from an outlet of each cylindrical barrel  1214 L,  1214 R, respectively, to the discharge end of the neck portion  1223 . The connecting channels  1224 L and  1224 R are compartmentalized by a separation unit  1225 , which is adapted to securely hold the plug  1221 . 
         [0162]    The plug  1221  includes a disc  1226 , a right leg  1227 R and a left leg  1227 L, which extends downwardly from the disc  1226 , and are separated by a vacancy slot  1228 . The size and shape of each leg ( 1227 L,  1227 R) is designed to tightly fit the corresponding connecting channels  1224 L,  1224 R, respectively. When the plug  1221  is pushed down and the separation unit  1225  fully engages with the vacancy slot  1228 , the left and right legs  1227 L,  1227 R, substantially block the connecting channels  1224 L,  1224 R, respectively, and a tight seal of each connecting channel is formed to prevent the components from premature mixing with each other. 
         [0163]    The mixing tip  1230  may include a tip portion  1231  and a thread portion  1232 . The mixing element  1222  is closely received and wedged within the bore of the tapered tip portion  1231 . The thread portion  1232  is adapted to attach to the pre-mixing neck portion  1223  by screwing onto portion of the outer surface thereof to control the position of the plug  1221 . 
         [0164]    For example, when the mixing tip  1230  is screwed all the way down on the neck portion  1223 , the syringe is at its closed position, and at least part of the thread portion  1232  engages with the disc  1226  of the plug  1221 , as shown in  FIG. 12B . An opened position may be achieved when a user makes an upward quarter or half turn of the mixing tip  1230  to disengage the disc  1226 . In other words, the plug  1221  is freely suspended within the tip portion  1231  after an upward quarter or half turn of the mixing tip  1230 . Thus, when appropriate force is applied from the double-plunger assembly  1212  to the components in the barrels  1214 L,  1214 R, the disengaged plug  1221  is accordingly lifted away from the closed position to allow the component in each barrel to move toward the tip portion of the mixing tip  1230  where the components are mixed to form an admixture for dispensing. The syringe in the present embodiment can be resealed simply by screwing down the mixing tip  1230  again. 
         [0165]    The size of the disc  1226  is at least the same size as the discharge end of the neck portion  1223 , so as to cover the discharge end thereof to minimize or prevent the components in the barrels  1214 L,  1214 R from leaking or premature mixing with the other component. 
         [0166]    In some aspects, the rotatable mixing tip itself may serve as a plug which is also not integrated with the mixing element. As shown in  FIGS. 13 and 13A , for example, the syringe  1300  may include a syringe barrel  1310 , a mixing and switching assembly  1320  including a hemispheric channel blocker  1321  and a mixing element  1322 , and a rotatable mixing tip  1330 . Similar to other embodiments previously illustrated, the syringe barrel  1310  may include a double-barrel assembly  1312  that may have, for example, juxtaposed first and second generally cylindrical barrels  1314 L,  1314 R, respectively, which may have a common length and a generally cylindrical bore  1316 L,  1316 R, respectively. The syringe barrel  1310  may further include a double-plunger assembly  1336  that may have juxtaposed generally cylindrical first and second plungers  1338 L,  1338 R of a common length. 
         [0167]    Referring to  FIG. 13A  and  FIG. 13B , a pre-mixing neck portion  1323  may have juxtaposed first and second connecting channels  1324 L,  1324 R, respectively. Each connecting channel extends from an outlet of each cylindrical barrel  1314 L,  1314 R, respectively, to the discharge end of the neck portion  1323 . The connecting channels  1324 L and  1324 R are compartmentalized by a separation unit  1325 . 
         [0168]    The mixing tip  1330  may include a tip portion  1331  and a thread portion  1332 . The mixing element  1320  is closely received and wedged within the bore of the tapered tip portion  1331 . The thread portion  1332  is adapted to attach to the pre-mixing neck portion  1323  by screwing onto portion of the outer surface thereof to control the position of the mixing tip  1330 . 
         [0169]    Still referring to  FIGS. 13A and 13B , the hemispheric channel blocker  1321  may be, for example, integrated with the tip portion  1331  and located within the mixing tip  1330 . More for example, the hemispheric channel blocker  1321  extends downwardly from lower tip portion  1331 , and is located between the tip portion  1331  and the thread portion  1332 , wherein the hemispheric channel blocker  1321 , with a hollow interior, has an opening  1326  with full fluid communication with the bore of the tapered tip portion  1331 , which receives and wedges the mixing element  1322 . In other words, at least portion of the mixing element  1322  may be located within the hemispheric channel blocker  1321 . 
         [0170]    The separation unit  1325  is arranged to receive the channel blocker  1321  wherein the size and shape of the separation unit  1325  is designed to tightly fit with an outer surface  1327  of the hemispheric channel blocker  1321 , which is adapted to substantially block the connecting channel  1324 L,  1324 R, respectively. As can be seen in  FIG. 13C , for example, when a user screws the mixing tip  1330  all the way down to close it, the outer surface  1327  of the hemispheric channel blocker  1321  is accordingly moved down to substantially block the connecting channels  1324 L,  1324 R, respectively, and a tight seal of each connecting channel is formed to prevent the components from premature mixing with each other. 
         [0171]    An opened position of the syringe may be achieved when the user makes an upward quarter or half turn of the mixing tip  1330  to move the hemispheric outer surface  1327  away from the connecting channels  1324 L,  1324 R, respectively. Thus, when appropriate force is applied from the double-plunger assembly  1312  to the components in the barrels  1314 L,  1314 R, the component in each barrel is allowed to move toward the tip portion of the mixing tip  1330  where the components are mixed to form an admixture for dispensing. The syringe in the present embodiment can be resealed simply by screwing down the mixing tip  1330  again. 
         [0172]    It is worth mentioning that since the size (e.g. diameter) of the connecting channels ( 1024 L,  1024 R,  1124 L,  1124 R,  1224 L,  1224 R,  1324 L,  1324 R) is relatively smaller than that of the barrels ( 1014 L,  1014 R,  1114 L,  1114 R,  1214 L,  1214 R,  1314 L,  1314 R), relatively higher pressure may be applied by the user to force the components from the barrels to the connecting channels. In other words, the flow rate decreases when the components move from the barrels to the connecting channels. Accordingly, the retention time of the components in the mixing element increases, and the mixing is thus enhanced. 
         [0173]    In some aspects, the static mixing element may be formed integrally with the tip of a syringe.  FIG. 9  illustrates an embodiment of a mixing and dispensing tip  900  that may include integral static mixing formations. The tip  900  may be formed from as a single component with multiple sections  902  that may form a full tip  900  when assembled. For example, the multiple sections  902  may be sectors of a cylinder, sectors of a cone, sections of prism, and/or any other appropriate components of a physical form that may be utilized as a tip. The tip  900  may include any number of sections  902  that may be effective in constructing a fully formed tip. In general, a greater number of sections may not necessarily improve the performance and/or usability of the tip and thus a low number, such as two or three sections, may be utilized to simplify design, construction and/or assembly. The sections may include hinges  906  between them. The hinges  906  may be, for example, living hinges such that they may be integrally constructed into the tip  900  and may not require any additional manufacture or assembly. 
         [0174]    The sections  902  may include on their inner surfaces multiple fins or baffles  904 . The fins or baffles may be angled, spaced and/or staggered in any appropriate configuration such as, for example, at an offset in each section such that when assembled, the fins or baffles  904  alternate from each section from one end of the tip to the other. The fins or baffles  904  may also be of an appropriate size such that they may provide an adequate mixing environment and may allow the composition to substantially pass through the tip  900  without significant obstruction to the flow. The fins or baffles may also overlap when the tip  900  is assembled and viewed from either end, as illustrated in  FIG. 9A . 
         [0175]    In other embodiments, the tip  900  may include a static mixing element where the fins or baffles  904  may form flow obstructions with offset flow channels.  FIG. 9C  illustrates an embodiment of a dispensing and mixing tip that may include multiple sections  902 . The multiple sections  902  may include disposed on their inner surface a series of fins or baffles  904  that, when the tip  900  is properly assembled, may substantially form flow obstructions. The fins or baffles  904  may, as shown in  FIG. 9D , form portions of an internal structure that may substantially block flow. The flow obstructions may occur at regular or irregular intervals through the length of the tip  900 . Each obstruction that may be formed by a particular set of fins or baffles  904  may also include a set of holes or flow channels  905  that may substantially allow passage of a flow therethrough. The holes or flow channels  905  may be formed in a regular pattern on each obstruction and may, in general, be situated around the central axis of the tip  900 . The holes or flow channels  905  may further be offset from each other in each successive obstruction such that, when viewed from one end of tip  900 , no straight-through flow path may be formed by the holes or flow channels  905 . This configuration may allow the obstructions and the holes or flow channels  905  to form a static mixing element, as a multiphase flow entering from one end may be substantially split and recombined in multiple radial orientations about the center axis of the tip  900 , and may be substantially mixed upon exiting from the outlet end. 
         [0176]    The tip  900  may be assembled by rolling the sections  902  onto each other such that the free edges  907 ,  908  meet, utilizing the living hinges  906 . The free edges  907 ,  908  may be joined by a variety of methods including, but not limited to, adhesives, welding, melting, fasteners, and/or any other appropriate method. Alternatively, the tip  900  may be housed within an external form  910 , such as, for example, a cylinder, cone or other shape appropriate to the shape of the tip  900 , such that the external form  910  may serve to hold the tip together, as shown in  FIG. 9B . 
         [0177]    In some embodiments, the tip  900  may be adapted form a dynamic mixing element. The tip  900  may be adapted to move within the external form  910  in, for example, a rotational manner, such that the fins or baffles  904  may serve as the effective moving parts of a dynamic mixing element. 
         [0178]    The tip  900  may be manufactured by a variety of methods, including, but not limited to, injection molding, extrusion, casting, machining, and/or any other appropriate method, and may be fabricated as a unit from a suitable material, such as, for example, polymeric materials that may include polypropylene, polyethylene, polycarbonate, polyacrylic polymers, polystyrene and/or any other suitable material, as mentioned before. 
         [0179]    In some embodiments, the mixing element may be formed integrally within the rotatable head  1030  as shown in  FIG. 10E . The rotatable head  1030  may be formed from as a single component with multiple sections  1090  that may form a full tip portion of the rotatable head  1030  when assembled. In the present embodiment, two sections may be utilized to simplify design, construction and/or assembly. The sections  1090  may include on their inner surfaces multiple fins or baffles  1092 . The fins or baffles  1092  may be angled, spaced and/or staggered in any appropriate configuration such as, for example, at an offset in each section such that when assembled, the fins or baffles  1092  alternate from each section from one end of the tip to the other. The fins or baffles  1092  may also be of an appropriate size such that they may provide an adequate mixing environment and may allow the composition to substantially pass through the tip portion of the rotatable head without significant obstruction to the flow. The fins or baffles  1092  may also overlap when the rotatable head  1030  is assembled and viewed from the top, as illustrated in  FIG. 10E . 
         [0180]    In other embodiments, the tip portion of the rotatable head  1030  may include a mixing element where the fins or baffles  1093  may form flow obstructions with offset flow channels. As shown in  FIG. 10F , the multiple sections  1090  may include a series of fins or baffles  1093  disposed on their inner surface, which may substantially form flow obstructions when the rotatable head  1030  is properly assembled. The fins or baffles  1093  may, as shown in  FIG. 10H , form portions of an internal structure that may substantially block flow. The flow obstructions may occur at regular or irregular intervals through the length of the tip portion of the rotatable head  1030 . In one embodiment, each obstruction that may be formed by a particular set of fins or baffles  1093  may also include a set of holes or flow channels  1094  that may substantially allow passage of a flow therethrough, as can be seen in  FIG. 10G . The holes or flow channels  1094  may be formed in a regular or irregular pattern on each obstruction and may, in general, be situated about the central axis of the tip portion  1032  of the rotatable head  1030 . The holes or flow channels  1094  may further be offset from each other in each successive obstruction such that, when viewed from the top of the rotatable head  1030 , no straight-through flow path may be formed by the holes or flow channels  1094 . This configuration may allow the obstructions and the holes or flow channels  1094  to form a mixing element, as a multiphase flow entering from one end may be substantially split and recombined in multiple radial orientations about the center axis of the rotatable head  1030 , and may be substantially mixed upon exiting from the outlet end. 
         [0181]    As noted above, the components may be mixed in various proportions such as 1:1, 1:2, 1:3, 1:4, 1:5 or so on, and thus the compartments or chambers of the syringe or container may be of the same or different sizes or diameters, as desired. Also, the number of compartments or chambers may vary from two to more than two. 
         [0182]    While exemplified embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Accordingly, the invention is not to be considered as limited by the foregoing description, but is only limited by the scope of the claims appended hereto.