Patent Publication Number: US-10307336-B1

Title: System and method for mixing and delivering a solution

Description:
TECHNICAL FIELD 
     The presently disclosed subject matter relates to a system and method for mixing and delivering a solution, such as buffered anesthetics. 
     BACKGROUND 
     Local anesthetics have been used for decades to decrease and/or eliminate the perception of pain to a patient. Local anesthetics function by blocking an ion channel upstream of a particular triggered nerve to impede all signals (e.g., pain) to the patient&#39;s brain. Local anesthetics are typically acidified to a pH of about 3.5 to 4.5 to increase stability, resulting in a longer shelf life. Once administered, the body of the patient must buffer the local anesthetic to a pH of 7.4 (the pH of the body) before the full effectiveness or numbness of the local anesthetic is achieved, which can take up to 20 minutes. Further, administering an acidic local anesthetic into human tissues creates a painful or burning sensation. Changing the pH of a local anesthetic to more closely mimic the pH of human tissue has been found to significantly decrease injection-associated pain. However, current methods of buffering local anesthetics are wasteful, time consuming, and expensive. Further, current methods are non-standardized, leaving room for human error. Particularly, physicians typically mix sodium carbonate (pH 8.4) with a desired local anesthetic at a ratio of 9:1 anesthetic to sodium bicarbonate by drawing a desired amount from larger vials of solution. Such a method is unmeasured and non-standardized. In addition, each large vial of buffered anesthetic solution is intended for a single patient, and is discarded after use. The physician will therefore discard the wasted solution or continue to use the vials on future patients, risking cross contamination. It would therefore be beneficial to provide a system and method that overcomes the shortcomings of the prior art. 
     SUMMARY 
     In some embodiments, the presently disclosed subject matter is directed to a device for mixing and delivering a solution. Particularly, the device comprises a tubular barrel comprising a first end, a second end, and interior compartment that houses a first solution to be mixed. The device further comprises a plunger positionable at the first end of the barrel, moveable within the interior compartment of the barrel. The device includes a deformable container positioned at the second end of the barrel, wherein the container comprises a needle-receiving opening, a membrane wall that abuts interior compartment of the barrel, and an internal compartment that houses a second solution to be mixed. The container membrane wall can be ruptured in response to an increase in internal container pressure, thereby allowing first and second solutions to intermix. The device plunger can be activated repeatedly to provide a mixing ability. 
     In some embodiments, the presently disclosed subject matter is directed to a method of mixing and dispensing first and second solutions on demand. The method comprises deforming the container of the disclosed device, wherein the deforming increases the internal pressure within the container internal compartment. The membrane is thereby ruptured, allowing the first and second solutions to be dispersed within the interior of the barrel compartment. The first and second solutions can be further mixed by shaking or moving the device. The solution can then be dispensed through the device opening. 
     In some embodiments, the presently disclosed subject matter is directed to a device for mixing and delivering a solution. Particularly, the device comprises a tubular barrel comprising a first end, a second end comprising a needle-receiving opening, and interior compartment comprising a first solution to be mixed. The device includes a plunger positionable at the first end of the barrel, moveable within the interior compartment of the barrel. The device further comprises a container positioned within the interior barrel compartment, directly adjacent to the plunger, wherein the container comprises an internal compartment comprising a second solution to be mixed and a membrane wall that abuts the interior compartment of the barrel. The device comprises an agitator positioned within the interior compartment of the barrel. The membrane wall is configured to be ruptured by the agitator in response to impact, thereby allowing the first and second solutions to intermix. 
     In some embodiments, the presently disclosed subject matter is directed to a method of mixing and dispensing first and second solutions on demand. The method comprises shaking or moving the disclosed device, wherein the agitator ruptures the membrane, thereby allowing the first and second solutions to be dispersed within the interior of the barrel compartment. The first and second solutions can be further mixed by shaking or moving the device. The mixed solution can then be dispensed through the opening. 
     In some embodiments, the presently disclosed subject matter is directed to a device for mixing and delivering a solution. Particularly, the device comprises a compressible tubular barrel comprising a first end, a second end comprising a needle-receiving opening, and interior compartment comprising a first solution to be mixed. The device further includes a plunger positionable at the first end of the barrel, moveable within the interior compartment of the barrel, and a container positioned within the interior barrel compartment, wherein the container comprises an internal compartment comprising a second solution to be mixed. The container is configured to be ruptured in response increased pressure, thereby allowing the first and second solutions to intermix. 
     In some embodiments, the presently disclosed subject matter is directed to a method of mixing and dispensing first and second solutions on demand. The method comprises manipulating the barrel of the disclosed device to rupture the container configured within the interior of the barrel, thereby allowing the first and second solutions to intermix. The first and second solutions can be further intermixed by shaking or moving the device. The mixed solution can then be dispensed through the opening. 
     In some embodiments, the first solution is a local anesthetic solution. In some embodiments, the local anesthetic solution is selected from one or more of articaine, bupivacaine, carticaine, cinchocaine/dibucaine, etidocaine, levobupivacaine, lidocaine/lignocaine, mepivacaine, piperocaine, prilocaine, ropivacaine, trimecaine, procaine/benzocaine, chloroprocaine, cyclomethycaine, dimethocaine/larocaine, propoxycaine, procaine/novocaine, proparacaine, tetracaine/amethocaine, lidocaine/prilocaine, saxitoxin, tetrodotoxin, and pharmaceutically acceptable salts thereof. 
     In some embodiments, the second solution is a buffer. In some embodiments, the buffer is selected from one or more of sodium bicarbonate, potassium carbonate, calcium carbonate, ammonium carbonate, and magnesium carbonate. 
     In some embodiments, the plunger comprises a main body with an exterior cross-sectional circumference that is approximately equal to the interior cross-sectional circumference of the barrel. 
     In some embodiments, at least a portion of the barrel is transparent. In some embodiments, the plunger further comprises an extension portion with an exterior cross-sectional circumference that is approximately equal to the interior cross-sectional circumference of the container, and wherein the extension is configured directly adjacent to the interior compartment of the barrel. In some embodiments, the main body of the plunger comprises one or more sealing ribs. 
     In some embodiments, the container comprises a neck that is sized and shaped to fit into the interior of the second end of the barrel interior compartment. 
     In some embodiments, the container membrane is frangible. In some embodiments, the container membrane comprises one or more weakened areas comprising perforations, thinner material, or both. 
     In some embodiments, the container opening comprises a removable cap. 
     In some embodiments, the agitator comprises a plastic or metal element with one or more sharp angles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The previous summary and the following detailed descriptions are to be read in view of the drawings, which illustrate some (but not all) embodiments of the presently disclosed subject matter. 
         FIG. 1 a    is side plan view a device that can be used to mix and deliver first and second solutions in accordance with some embodiments of the presently disclosed subject matter. 
         FIG. 1 b    is a cross-sectional side view of the device of  FIG. 1   a.    
         FIG. 2  is a perspective view of a barrel in accordance with some embodiments of the presently disclosed subject matter. 
         FIGS. 3 a  and 3 b    are front plan view of plungers that can be used with the disclosed device in accordance with some embodiments. 
         FIGS. 4 a  and 4 b    are side plan views of containers that can be used with the disclosed device in accordance with some embodiments. 
         FIGS. 5 a  and 5 b    are front plan views of one embodiment of assembling the disclosed device. 
         FIGS. 6 a  and 6 b    are front plan views of one embodiment of using the disclosed device. 
         FIG. 7 a    illustrates a side plan view of a mixing and dispensing device in accordance with some embodiments of the presently disclosed subject matter. 
         FIG. 7 b    is a side plan view of the device of  FIG. 7 a    in use. 
         FIG. 8 a    is a side plan view of a mixing and dispensing device in accordance with some embodiments of the presently disclosed subject matter. 
         FIG. 8 b    is a side plan view of the device of  FIG. 8 a    during use. 
     
    
    
     DETAILED DESCRIPTION 
     The presently disclosed subject matter is introduced with sufficient details to provide an understanding of one or more particular embodiments of broader inventive subject matters. The descriptions expound upon and exemplify features of those embodiments without limiting the inventive subject matters to the explicitly described embodiments and features. Considerations in view of these descriptions will likely give rise to additional and similar embodiments and features without departing from the scope of the presently disclosed subject matter. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter pertains. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described. 
     Following long-standing patent law convention, the terms “a”, “an”, and “the” refer to “one or more” when used in the subject specification, including the claims. Thus, for example, reference to “a carpule” can include a plurality of such carpules, and so forth. 
     Unless otherwise indicated, all numbers expressing quantities of components, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the instant specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter. 
     As used herein, the term “about”, when referring to a value or to an amount of mass, weight, time, volume, concentration, and/or percentage can encompass variations of, in some embodiments +/−20%, in some embodiments +/−10%, in some embodiments +/−5%, in some embodiments +/−1%, in some embodiments +/−0.5%, and in some embodiments +/−0.1%, from the specified amount, as such variations are appropriate in the disclosed packages and methods. 
     The presently disclosed subject matter is directed to a device for dispensing a mixture of a first composition (e.g., a drug) and a second composition (e.g., a diluent buffer, a second drug, or a solution).  FIGS. 1 a  and 1 b    illustrate one embodiment of device  5  comprising plunger  10  that slidably engages with the interior of device barrel  15  at first end  20 . Second end  25  of the device barrel includes flexible container  30  configured to house one or more solutions (e.g., sodium bicarbonate). Container  30  comprises membrane  35  positioned adjacent to the interior of the barrel, and exterior opening  40  facing the exterior environment. Opening  40  is covered by cap  45 . First solution  50  (e.g., a local anesthetic) is housed within the interior of barrel  15 , and second solution  55  (e.g., a buffer) is housed within the interior of container  30 . As described in more detail herein below, the two solutions can be mixed on demand as needed by a physician to provide a buffered anesthetic solution. It should be appreciated that the presently disclosed subject matter is not limited, and the first and second solutions can be any two solutions (or powders) that are to be mixed on demand. 
     In some embodiments, device  5  is a carpule mixing device. The term “carpule” refers to a container, such as a vial, cartridge, or the like, generally made of glass and adapted to house a dose of a medical fluid. The carpule can be inserted into a syringe for dispensing (e.g., injecting) into a patient. Carpules typically include a puncturable cap on one end and a sliding plug on the other end. The cap can be punctured by the tip of a needle assembly of a carpule syringe to allow the fluid housed within the carpule to be dispensed. The plug is advanced towards the cap end of the carpule via a syringe plunger. 
       FIG. 2  illustrates one embodiment of barrel  15  that can be used with device  5 . As shown, in some embodiments, the barrel can be configured in a cylindrical shape with hollow interior  60  and open ends  20 ,  25 . However, the presently disclosed subject matter is not limited and the barrel can have any desired shape. The hollow interior of the barrel allows the movement of a plunger from first end  20  to second end  25 . In this way, fluid housed within the barrel can be dispensed. 
     Barrel  15  can be constructed from any desired material, such as (but not limited to) glass, polymeric material, ceramic material, metal (e.g., stainless steel), or combinations thereof. In some embodiments, the material used to construct barrel  15  can be at least partially transparent to allow the user to monitor mixing of the first and second solutions. The term “transparent” refers to a material property that permits transmission of at least 50% of the light directed at a first side of the material through the other side of the material. 
     The device barrel can be configured in any desired size, dependent upon the dosage of mixed solution. For example, the barrel can house an internal fluid volume of about 0.5-10 mL. Thus, barrel  5  can have an internal volume of at least about (or no more than about) 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mL. However, it should be appreciated that the device is not limited, and the barrel can be configured larger or smaller than the range set forth above. 
     First solution  50  is housed within the interior of barrel  15 . First solution  50  can include any solution that can be mixed with a second solution. For example, in some embodiments, the first solution can include a drug, such as a local anesthetic solution. The term “local anesthetic” refers to any anesthetic agent that induces local anesthesia by reversibly inhibiting peripheral nerve excitation and/or transmission. Suitable local anesthetics can comprise any known local anesthetic, including (but not limited to) articaine, bupivacaine, carticaine, cinchocaine/dibucaine, etidocaine, levobupivacaine, lidocaine/lignocaine, mepivacaine, piperocaine, prilocaine, ropivacaine, trimecaine, procaine/benzocaine, chloroprocaine, cyclomethycaine, dimethocaine/larocaine, propoxycaine, procaine/novocaine, proparacaine, tetracaine/amethocaine, lidocaine/prilocaine, saxitoxin, tetrodotoxin, and pharmaceutically acceptable salts thereof. In some embodiments, first solution  50  can include a mixture of more than one solution, such as more than one local anesthetics. 
     As set forth above, plunger  10  is positioned within the interior of barrel  15  and travels from first end  20  to second end  25  to dispense the fluid housed within the device interior.  FIG. 3 a    illustrates one embodiment of plunger  10  comprising main body  65  and optional extension  70 . The plunger main body has a size and shape that corresponds to the interior of barrel  15  to allow movement from one end to the other. Particularly, the inner diameter of barrel  15  is equal to the outer diameter of main body  65 . Thus, if the inner diameter of the barrel is configured with a round cross-sectional shape having a diameter of 0.5 inches, the outer diameter of main body  65  also is configured with a round cross-sectional shape with a diameter of 0.5 inches. In this way, the main body slides in an axial direction through the inside of the barrel to dispense the mixed solution. Further, the plunger main body provides a fluid-tight seal within the interior of the barrel such that fluid cannot leak from the device. 
     In some embodiments, main body  65  includes one or more ribs  75  positioned about the outer circumference. The ribs function as a sealing ring, ensuring no fluid leaks from the device. Particularly, the ribs are compressed within the tubular barrel, creating a seal that retains fluid within the device interior. The main body can include any number of ribs, such as about 1-5. Further, the ribs can be configured with any desired cross-sectional shape (e.g., square, circular, oval, rectangular). It should be appreciated that ribs  75  are optional, and in some embodiments main body  65  can be configured without ribs. 
     Plunger extension  70  has an outer diameter that is less than the outer diameter of main body  65 , as shown. In some embodiments, the outer diameter of the extension can be about 2-50 percent smaller than the outer diameter of the main body. Extension  70  is sized and shaped to cooperate with the interior of cap  30 . Particularly, the extension is configured to axially move into the interior of container  30  to dispense fluid from opening  40 , as discussed in more detail herein below. Thus, the outer circumference of extension  70  has the same cross-sectional shape and size as the interior of cap  30 . It should be appreciated that in some embodiments, extension  70  is optional, as shown in the embodiment of  FIG. 3   b.    
     Any suitable material can be used to construct plunger  10 , such as (but not limited to) rubber, polymeric material, and combinations thereof. 
     As discussed above, second end  25  of the device comprises container  30 , as illustrated in  FIG. 4 a   . Particularly, container  30  comprises neck  80  that is sized and shaped to fit into the interior of barrel  15 . Thus, the outer diameter of neck  80  is the same or about the same as the interior diameter of barrel  15 . In some embodiments, the outer circumference of neck  80  includes one or more connection elements to allow the container to releasably attach to the barrel. For example, one or more threads  90  can be positioned about the outer circumference of the neck, cooperating with indentations on the interior of barrel  15  at second end  25 . However, container  30  can attach to the barrel using any known mechanism, such as mechanical closures (screws, clips, etc.), adhesives, snap-fit engagement, slide fit engagement, and the like. 
     Container  30  includes interior compartment  95  that houses second solution  55 . Second solution  55  can include any solution that can be mixed with first solution  50 . For example, in some embodiments, the second solution can include a buffer. The term “buffer” refers to an aqueous solution comprising a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. In some embodiments, second solution  55  can comprise one or more of sodium bicarbonate, potassium carbonate, calcium carbonate, ammonium carbonate, and magnesium carbonate. Container  30  can house any desired volume of second solution  55 , such as (but not limited to) a volume of about 0.1-5 mL. In some embodiments, the ratio of first solution  50  to second solution  55  can be about 1:1 to about 1:20. 
     Membrane  35  spans the open end of neck  80 , adjacent to the interior of the barrel. The term “membrane” as used herein refers to a thin layer of material that separates the interior compartment of container  30  from the interior compartment of barrel  15 . Membrane  35  can be constructed from any desired material, including (but not limited to) one or more polymeric materials, metal foil, elastomeric material, and the like. In some embodiments, the membrane can have a thickness of about 2-100 μm. However, it should be appreciated that the thickness of the membrane is not limited and can be configured outside the range set forth above. 
     In some embodiments, membrane  35  is frangible. The term “frangible” refers to the characteristic of being breakable, such as by force or pressure. Thus, in some embodiments, membrane  35  can have one or more weakened areas (e.g., thinner material, perforations, etc.). In use, membrane  35  is ruptured to allow the contents of the cap and barrel to intermix. 
     Container  30  further comprises lip  85  that fits over the second end of the barrel, creating a dispensing unit. In some embodiments, the lip has a larger diameter than the outer diameter of barrel  15 . The lip includes opening  40  through which the mixed fluid is dispensed. The opening can have any shape that allows fluid to exit container  30 . For example, the opening can be straight, as depicted in  FIG. 4 a   , or the opening can follow a more tortuous path to allow fluid to be dispensed while resisting the escape of material. 
     As shown in  FIG. 4 b   , cap  45  is positioned over opening  40  to create sealed interior compartment  95 . For example, the interior compartment of container  30  can be filled with a desired amount of second fluid  55  through opening  40 . The cap is then used to seal the container contents from the outside environment. The cap can further be used as an access point for the insertion of a syringe needle. Cap  45  can be constructed from any desired material, such as (but not limited to) polymeric material, metal foil, and/or elastomeric material. 
     Container  30  can be constructed from any flexible material. The term “flexible” refers to the characteristic of bending without breaking. In some embodiments, the container can be constructed from one or more polymeric materials, elastomeric material, rubber, and the like. 
       FIGS. 5 a -5 b    illustrate one method of assembling device  5 . As shown, plunger  10  can be positioned within the interior of barrel  15 , at first end  20  such that plunger extension  70  faces the interior of the barrel. Container  30  can be positioned on second end  25  of the barrel, such that container membrane  35  faces the interior of the barrel. It should be appreciated that in some embodiments, the container can be initially positioned on barrel  15 , followed by positioning of the plunger. Interior compartment  60  of the barrel is filled with a desired amount of first fluid  50  using any known method. For example, after plunger  10  is configured on the first end of the barrel, the fluid can be added, followed by positioning of the container on second end  25  to ensure that the fluid is maintained within the device interior. 
     In some embodiments, the device of  FIG. 5 b    can be deposited into a reusable syringe that includes a rod that manually engages plunger  10 . In this way, anesthetic solution is pushed through the entire device. A standard hollow-born needle can be screwed into the metal syringe for stability. One end of the needle pierces cap  45 , providing access to the mixed solution (e.g., buffered anesthetic). The second end of the needle can be used to administer the mixed solution into the desired body tissue. 
       FIGS. 6 a  and 6 b    illustrate one embodiment of the disclosed device during use. As shown, a user applies pressure (such as with a finger) to flexible container  30  at second end  25  of the device. The user manipulates the flexible container towards the interior compartment of barrel  15 . As a result, flexible container  30  is deformed, causing an increase in pressure within the container interior. Membrane  35  ruptures from the increased pressure, releasing second solution  55  into the interior of the barrel to intermix with first solution  50 . Continuous pumping of the flexible container creates mixing within the interior of the device, as shown in  FIG. 6 b   . The user (e.g., physician) can then insert a dispensing needle into membrane of cap  45  to dispense the mixed solution on demand. The plunger is advanced towards second end  25 , until extension  70  rests within the interior of compartment  30 . The device can then be disposed of. 
       FIG. 7 a    illustrates an alternate embodiment of device  5 . As shown, barrel  15  includes a tapered nozzle at second end  25 . The nozzle includes opening  40  and cap  45  to allow the interior of the barrel to be filled with a desired amount first fluid  50  (e.g., anesthetic solution). The opening also includes pierceable membrane  95  that allows a user to access the interior of the barrel, such as during dispensing of the mixed fluid. Container  105  houses second fluid  55  (e.g., sodium bicarbonate), and is positioned at first end  20  of the device, between the internal barrel compartment and plunger  10 . Container  30  comprises membrane  35 , positioned directly adjacent to the interior barrel compartment. Plunger  10  is positioned at first end  20 , between container  30  and the external environment. In some embodiments, compartment  30  and plunger  10  can be configured in an insert sleeve to allow for easy insertion into the first end of the barrel. Insert sleeve  105  can be constructed from any desired material, such as polymeric material, metal foil, and the like. 
     One or more agitators  110  are dispersed within first fluid  50  or second fluid  55 . The term “agitator” as used herein refers to any object capable of piercing membrane  35 . In some embodiments, the agitator can be configured as a sharp object, such as an angled piece of plastic or metal. The agitator functions to rupture membrane  35  to allow first and second fluids  50 ,  55  to intermix. Thus, in use, the user shakes the device to move agitator  110  within the interior of the barrel until it contacts and ruptures membrane  35 , as shown in  FIG. 7 b   . The user can continue shaking the device until the solutions are intermixed. The user can then advance plunger  10  towards second end  25 . In this way, the mixed solution can be dispensed to a patient in need thereof. It should be appreciated that agitator  110  is sized such that it cannot pass through opening  40 . 
       FIGS. 8 a  and 8 b    illustrate a further embodiment of device  5 . As shown, barrel  15  is configured from a flexible material and includes a tapered nozzle at second end  25 . The nozzle includes opening  40  and cap  45  to allow the interior of the barrel to be filled with a desired amount first fluid  50  (e.g., anesthetic solution). The opening also includes pierceable membrane  95  that allows a user to access the interior of the barrel, such as during dispensing of the mixed fluid. For example, a user can pierce membrane  100  to cooperatively attach a dispensing needle. Plunger  10  is positioned at first end  20  of the barrel, between the inner barrel compartment and the exterior environment. Second solution  55  (e.g., a buffer) is housed within flexible container  115 , positioned within the interior compartment of barrel  15 . In some embodiments, the flexible container can be configured as a pouch or other easily manipulatable receptacle. 
     In use, a user can manipulate the exterior of flexible barrel  15  with the fingers (i.e., through a pinching or squeezing motion) to rupture flexible container  115  housed within the barrel interior, as shown in  FIG. 8 b   . In this way, second solution  55  housed within container  115  is intermixed with first solution  50  housed within the barrel interior compartment. The user can then dispense the mixed solution as described herein above. 
     Advantageously, the disclosed system and method allows a user to prepare and intermix two solutions on demand. The user can mix a desired amount of solution, and does not waste excess fluid, thereby providing a cost savings. 
     Further, the disclosed device enables the user to prepare a mixed solution on demand, thereby optimizing the mixed solution&#39;s shelf life. 
     The disclosed system and method further provide a standardized method of buffering anesthetic directly prior to administering to a patient. The two solutions are pre-measured, thereby reducing the likelihood of measurement errors.