Patent Application
20180361355
The invention relates to systems and methods for disinfecting, recharging, and conditioning zirconium oxide in a reusable sorbent module. The systems and methods provide for reuse by recharging and conditioning a zirconium oxide sorbent module after being used in dialysis.
Zirconium oxide containing sorbent cartridges are used in dialysis to remove phosphate and other anions from dialysate, allowing the dialysate to be reused. Known systems for reusing zirconium oxide require the zirconium oxide to be removed from a sorbent cartridge, transported to a reprocessor, treated, and placed into a new sorbent cartridge, increasing costs and waste associated with reuse of zirconium oxide. Known systems and methods also cannot reuse a zirconium oxide sorbent module by concurrently disinfecting the ZO to reduce the microbial load to acceptable levels, recharging to recover the capacity of the zirconium oxide, and conditioning the zirconium oxide to return the zirconium oxide to an appropriate chemical state for use in dialysis. Hence, there is a need for systems and methods that can quickly, efficiently, and effectively disinfect, recharge and condition zirconium oxide in a reusable sorbent module. There is further a need for systems and methods that are optimized to carry out all three steps with the least amount of waste at reduced cost than known systems and methods.
The first aspect of the invention relates to a method for recharging zirconium oxide in a zirconium oxide sorbent module. In any embodiment, the method can include flowing a disinfectant solution through the zirconium oxide sorbent module and flowing a base solution through the zirconium oxide sorbent module; wherein the step of flowing the disinfectant solution through the zirconium oxide sorbent module includes any one of: (a) flowing an acid solution and a peracetic acid solution through the zirconium oxide sorbent module; (b) flowing a heated base solution through the zirconium oxide sorbent module; or (c) flowing a bleach solution through the zirconium oxide sorbent module.
In any embodiment, the base solution can be a sodium hydroxide solution.
In any embodiment, the step of flowing the acid solution and the peracetic acid solution through the zirconium oxide sorbent module can include flowing a mixture of acetic acid and peracetic acid through the zirconium oxide sorbent module. In any embodiment, the peracetic acid solution can also contain hydrogen peroxide.
In any embodiment, the mixture of acetic acid and peracetic acid can contain between 1% and 3% peracetic acid and between 5% and 15% acetic acid. In any embodiment, the peracetic acid solution can also contain hydrogen peroxide.
In any embodiment, the step of flowing the acid solution and the peracetic acid solution through the zirconium oxide sorbent module can include first flowing the acid solution through the zirconium oxide sorbent module; and then flowing the peracetic acid solution through the zirconium oxide sorbent module.
In any embodiment, the acid solution can contain acetic acid and sodium acetate.
In any embodiment, the acid solution can contain between 0.3M and 1.1M sodium acetate and between 0.2M and 0.8M acetic acid.
In any embodiment, the acid solution can further contain between 2.5 M and 4.9 M sodium chloride.
In any embodiment, the steps of flowing the base solution and flowing the disinfectant solution through the zirconium oxide sorbent module can include flowing a mixture of the base solution and disinfectant solution through the zirconium oxide sorbent module.
In any embodiment, the mixture of the base solution and disinfectant solution can be a mixture of sodium hydroxide and bleach.
In any embodiment, the mixture of sodium hydroxide and bleach can contain between 0.01% and 2.0% bleach and between 0.2 M and 2.0 M sodium hydroxide.
In any embodiment, a flow rate of the mixture of the base solution and disinfectant solution can be between 5 and 500 mL/min.
In any embodiment, the volume of the mixture of the base solution and disinfection solution flowed through the zirconium oxide sorbent module can be between 1.0 and 3.0 L.
In any embodiment, the method can include rinsing the zirconium oxide sorbent module with water after flowing the base solution through the zirconium oxide sorbent module.
In any embodiment, a volume of water flowed through the zirconium oxide sorbent module to rinse the zirconium oxide sorbent module can be between 100% and 1000% of a void volume of the zirconium oxide sorbent module.
In any embodiment, the method can include conditioning the zirconium oxide sorbent module by flowing a sodium bicarbonate solution through the zirconium oxide sorbent module.
In any embodiment, a pH of the sodium bicarbonate solution can be between 5.0 and 9.0.
In any embodiment, the method can include generating either or both of the disinfectant solution and base solution in a zirconium oxide recharging flow path.
In any embodiment, the method can include the step of flowing the sodium bicarbonate solution through a zirconium phosphate sorbent module prior to flowing the sodium bicarbonate solution through the zirconium oxide sorbent module.
In any embodiment, any one of (a) the step of flowing the disinfectant solution through the zirconium oxide sorbent module can include flowing a concentrated disinfectant solution and water to a static mixer to generate a dilute disinfectant solution; and flowing the dilute disinfectant solution through the zirconium oxide sorbent module; (b) the step of flowing the base solution through the zirconium oxide sorbent module can include flowing a concentrated base solution and water to a static mixer to generate a dilute base solution; and flowing the dilute base solution through the zirconium oxide sorbent module; or (c) combinations thereof.
The features disclosed as being part of the first aspect of the invention can be in the first aspect of the invention, either alone or in combination.
The second aspect of the invention is drawn to a zirconium oxide recharging flow path. In any embodiment, the zirconium oxide recharging flow path can include (i) a water source, a disinfectant source, a base source, and an acetic acid source; (ii) a zirconium oxide module inlet and a zirconium oxide module outlet; wherein the zirconium oxide module inlet and the zirconium oxide module outlet are fluidly connectable to a zirconium oxide sorbent module; (iii) at least one pump for flowing fluid from the water source, the disinfectant source, the base source, and the acetic acid source to the zirconium oxide module inlet; and (iv) a zirconium oxide effluent line fluidly connectable to the zirconium oxide module outlet.
In any embodiment, the disinfectant source can be a peracetic acid source.
In any embodiment, the acetic acid source can contain a mixture of acetic acid, sodium chloride, and sodium acetate.
In any embodiment, the disinfectant source can be a peracetic acid solution having a concentration in a range between 0.5% and 2% of peracetic acid in water.
In any embodiment, the acetic acid source can contain sodium chloride between 2.5 M and 4.9 M, sodium acetate between 0.3 M and 1.1 M, and acetic acid between 0.2 M and 0.8 M.
The features disclosed as being part of the second aspect of the invention can be in the second aspect of the invention, either alone or in combination.
The third aspect of the invention is drawn to a zirconium oxide recharging flow path. In any embodiment, the zirconium oxide recharging flow path can include (i) a water source and a base source; (ii) a zirconium oxide module inlet and a zirconium oxide module outlet; wherein the zirconium oxide module inlet and the zirconium oxide module outlet are fluidly connectable to a zirconium oxide sorbent module; (iii) at least one pump for flowing fluid from the water source and the base source to the zirconium oxide module inlet; and (iv) a zirconium oxide effluent line in fluid connection to the zirconium oxide module outlet.
In any embodiment, the base source can contain a mixture of sodium hydroxide and bleach.
In any embodiment, the base source can contain a concentrated solution of sodium hydroxide and bleach, and the zirconium oxide recharging flow path can include a static mixer, the static mixer fluidly connected to the water source and the base source.
In any embodiment, the base source can contain sodium hydroxide, and the zirconium oxide recharging flow path can have a heater.
The features disclosed as being part of the third aspect of the invention can be in the third aspect of the invention, either alone or in combination.
Unless defined otherwise, all technical and scientific terms used generally have the same meaning as commonly understood by one of ordinary skill in the art.
The articles “a” and “an” are used to refer to one or to over one (i.e., to at least one) of the grammatical object of the article. For example, “an element” means one element or over one element.
The term “acetic acid solution” refers to any aqueous solution containing acetic acid or CH3COOH.
The term “acetic acid source” refers to any source of a fluid containing acetic acid.
An “acid solution” as used can be a Lewis acid or a Bronsted-Lowry acid dissolved in water. A Lewis acid is capable of accepting a lone pair of electrons. A Bronsted-Lowry acid is capable of donating a hydrogen ion to another compound.
The term “base solution” refers to any aqueous solution containing hydroxide ions and a pH of greater than 7.0.
A “base source” is any source of a base solution.
The term “bleach solution” refers to any aqueous solution containing sodium hypochlorite.
The term “comprising” includes, but is not limited to, whatever follows the word “comprising.” Use of the term indicates the listed elements are required or mandatory but that other elements are optional and may be present.
A “concentrated” solution refers to a solution having at least one solute in a higher concentration than intended for use.
The terms “conditioning” or “to condition” refer to processes designed to allow safe and effective use of a component in dialysis.
The term “consisting of” includes and is limited to whatever follows the phrase “consisting of” The phrase indicates the limited elements are required or mandatory and that no other elements may be present.
The term “consisting essentially of” includes whatever follows the term “consisting essentially of” and additional elements, structures, acts or features that do not affect the basic operation of the apparatus, structure or method described.
A “dilute” solution refers to a concentrated solution after addition of a solvent to lower the solute concentration.
The term “disinfectant solution” refers to any solution capable of destroying or removing bacterial contaminants from a reusable sorbent module.
The term “disinfectant source” refers to any source of a disinfectant solution.
The terms “flowing” or to “flow” “refer to the movement of a fluid, gas, or mixtures thereof.
The term “flow rate” refers to the volume of a fluid moved in a flow path in a given period of time.
The term “fluidly connectable,” “fluidly connect,” “for fluid connection,” and the like, refer to the ability of providing for the passage of fluid, gas, or a combination thereof, from one point to another point. The two points can be within or between any one or more of compartments, modules, systems, components, and rechargers, all of any type. The connection can optionally be disconnected and then reconnected.
The terms “generating” or to “generate” refer to creating a fluid with a specified concentration, pH, temperature, and/or volume from one or more fluid sources.
A “heater” is a component capable of raising the temperature of a substance, container, or fluid.
The term “mixture” refers to a fluid having at least two components, the two components combined to form a substantially homogeneous substance.
The term “peracetic acid solution” refers to any aqueous solution containing peracetic acid or CH3COOOH. The peracetic acid solution can also include hydrogen peroxide and acetic acid in equilibrium with the peracetic acid.
The term “pH” refers to the negative log of the H+ concentration in a fluid when stated in moles of H+ per liter of fluid volume.
The term “pump” refers to any device that causes the movement of fluids, gases, or combinations thereof, by applying suction or pressure.
“Recharging” refers to treating a sorbent material to restore the functional capacity of the sorbent material to put the sorbent material back into a condition for reuse or use in a new dialysis session. In some instances, the total mass, weight and/or amount of “rechargeable” sorbent materials remain the same. In some instances, the total mass, weight and/or amount of “rechargeable” sorbent materials change. Without being limited to any one theory of invention, the recharging process may involve exchanging ions bound to the sorbent material with different ions, which in some instances may increase or decrease the total mass of the system. However, the total amount of the sorbent material will in some instances be unchanged by the recharging process. Upon a sorbent material undergoing “recharging,” the sorbent material can then be said to be “recharged.”
The term “rinsing” or to “rinse” refers to flowing water through a component to remove substances from the component.
The term “sodium bicarbonate solution” refers to any aqueous solution containing sodium bicarbonate or NaHCO3.
A “sorbent cartridge module” or “sorbent module” means a discreet component of a sorbent cartridge. Multiple sorbent cartridge modules can be fitted together to form a sorbent cartridge of two, three, or more sorbent cartridge modules. In some embodiments, a single sorbent cartridge module can contain all of the necessary materials for dialysis. In such cases, the sorbent cartridge module can be a “sorbent cartridge.”
A “static mixer” is a component configured to receive fluids from one or multiple sources and to mix the fluids together. The static mixer may include components that agitate the fluids to further mixing.
The term “void volume” refers to a volume contained in a cartridge, not including a sorbent or any other material, through which liquid can flow. The term “void volume” can also refer to the volume of a cartridge or container available for a liquid or gas to fill the cartridge or container.
A “water source” is a fluid source from which water can be obtained.
“Zirconium oxide,” also known as hydrous zirconium oxide, is a sorbent material that removes anions from a fluid, exchanging the removed anions for different anions.
A “zirconium oxide effluent line” is a fluid passageway, tube, or path of any kind into which fluid exiting a zirconium oxide sorbent module will flow.
A “zirconium oxide module inlet” is a connector through which a fluid, slurry, or aqueous solution can enter a zirconium oxide sorbent module.
A “zirconium oxide module outlet” is a connector through which a fluid, slurry, or aqueous solution can exit a zirconium oxide sorbent module.
A “zirconium oxide recharging flow path” is a path through which fluid can travel while recharging zirconium oxide in a reusable zirconium oxide sorbent module.
A “zirconium oxide sorbent module” is a sorbent module containing zirconium oxide.
A “zirconium phosphate module” or “zirconium phosphate sorbent module” is a sorbent module containing zirconium phosphate.
The method of disinfecting, recharging, and conditioning the zirconium oxide in a zirconium oxide sorbent module can begin in step 101. During use in dialysis, phosphate and other anions are adsorbed by the zirconium oxide. In step 102, the zirconium oxide sorbent module can optionally be rinsed with water to remove human dialysate waste. In some cases, the removal of human dialysate waste can make the disinfection of the zirconium oxide sorbent module more efficacious. The pre-rinsing in step 102 can include flowing water through the zirconium oxide sorbent module. The volume of water used can be any volume, including between 50 and 500% of the void volume of the zirconium oxide sorbent cartridge. However, the pre-rinsing step 102 is optional and can be omitted. In step 103, the zirconium oxide sorbent module is filled with a mixture of disinfectant solution and a base. In a preferred embodiment, the disinfectant solution is bleach, or a sodium hypochlorite solution. The base can be any hydroxide base, including sodium hydroxide, lithium hydroxide, potassium hydroxide, or any other hydroxide base. In a preferred embodiment, the base is sodium hydroxide. The sodium hydroxide concentration can range from 0.2M to 2.0M, with a preferred concentration of about 0.8M. The bleach concentration can range from 0.01 wt % to 2 wt % with a preferred concentration of 0.10 wt %. The preferred combined solution composition is 0.8M NaOH/0.10 wt % bleach. By combining the disinfectant and base in a single solution, the recharge and disinfection of the zirconium oxide can occur at the same time. The hydroxide base recovers the capacity of the zirconium oxide by exchanging the phosphate and other anions for hydroxide anions while the bleach disinfects the zirconium oxide. Another benefit of combining the base and bleach is the increased stability of sodium hypochlorite at high pH.
The volume of base and bleach flowed through the zirconium oxide sorbent module can vary depending on the size of the zirconium oxide sorbent module. The volume can be between 100 and 200% or more of the void volume of the zirconium oxide sorbent module, ensuring complete filling with the base and bleach solution. In a preferred embodiment, the volume of base and bleach flowed through the zirconium oxide sorbent module in step 103 is about 150% of the void volume of the zirconium oxide sorbent module. For example, with a 0.3 L zirconium oxide sorbent module, 0.45 L of the base and bleach solution can be flowed through the module in step 103. Any flow rate can be used in step 103, including between 5 and 500 mL/min. In a preferred embodiment, the flow rate is about 55 mL/min.
In step 104, the mixture of bleach and base solution is optionally held in the zirconium oxide sorbent module. Holding the bleach and base solution in the zirconium oxide sorbent module allows in-line neutralization of the effluent by aligning the zirconium oxide recharging process, which produces a basic effluent, with a zirconium phosphate recharging process, which produces an acidic effluent. The hold time can vary from 0 to 60 minutes depending on the hold time and flow rates used in the zirconium phosphate recharging process. In a preferred embodiment, the hold time is 25 minutes, which allows alignment with the zirconium phosphate recharging process. If the zirconium oxide is being recharged independently of zirconium phosphate, step 104 may be omitted.
In step 105, the mixture of bleach and base solution are again flowed through the zirconium oxide sorbent module. The concentrations and flow rates of bleach and base used in step 105 can be the same as described with reference to step 103. The total amount of bleach and base solution needed to recharge and disinfect the zirconium oxide can vary depending on the size of the zirconium oxide sorbent module, the concentrations of bleach and base in the solution, and the amount of phosphate or other anions adsorbed by the zirconium oxide during therapy. The total volume of bleach and base flowed through the zirconium oxide sorbent module can be between 1 and 3 L combined in steps 103 and 105. In a preferred embodiment, the total volume of bleach and base flowed through the zirconium oxide sorbent module is about 1.9 L of a 0.8M NaOH/0.10 wt % bleach solution, for a 310 g zirconium oxide sorbent module with a capacity to remove 250-mmol of phosphate.
In step 106, the zirconium oxide sorbent module is rinsed with water to remove the bleach and base solution. Removal of the bleach and base is necessary prior to reuse of the zirconium oxide sorbent module or for storage of the zirconium oxide sorbent module. The volume of rinse water flowed through the zirconium oxide sorbent module in step 106 can vary depending on the size of the zirconium oxide sorbent module. The volume can vary from 100% to 1000% of the zirconium oxide sorbent module void volume. In a preferred embodiment, the volume of rinse water flowed through the zirconium oxide sorbent module is 667% of the module void volume, or 2 L for a zirconium oxide sorbent module with a 0.3 L void volume. The rinse volume is chosen to reduce the residual bleach levels to 0.5-ppm total chlorine or less.
In step 107, the zirconium oxide sorbent module is conditioned with a sodium bicarbonate solution. Conditioning of the zirconium oxide is necessary to place the zirconium oxide in a state usable in dialysis. Without conditioning, the zirconium oxide will consume total carbonate from the dialysate. Conditioning of the zirconium oxide with sodium bicarbonate places the zirconium oxide in pH equilibrium with the bicarbonate conditioning solution. The conditioning solution is preferably a sodium bicarbonate solution at the same pH as effluent from the zirconium phosphate sorbent module during therapy, and can be between 5.0 and 9.0 depending on the needs of the patient and system. In a preferred embodiment, the pH of the conditioning solution is about 6.5. By equilibrating the zirconium oxide during step 107 with the zirconium phosphate effluent pH, the zirconium oxide sorbent module can be used without adversely affecting the dialysate pH during therapy.
The conditioning step 107 can take place in a recharger or in a dialysis console prior to therapy. To ensure that the conditioning solution is at the proper pH, the conditioning solution, containing bicarbonate, can be flowed through a zirconium phosphate module that has already been recharged to the proper pH. The effluent leaving the zirconium phosphate module will be at the desired conditioning pH, and the zirconium oxide sorbent module will eventually equilibrate to the desired pH during conditioning. Alternatively, a separate conditioning solution can be flowed through the zirconium oxide sorbent module, with the separate conditioning solution premade to a desired pH. The separate conditioning solution can be prepared by any method known in the art. In one non-limiting example, the separate conditioning solution can be a pressured solution of sodium bicarbonate and carbon dioxide. Alternatively, a solution of sodium bicarbonate can be mixed with an acid, such as acetic acid or HCl to generate a conditioning solution having a desired pH. The pH of the conditioning solution can be any pH usable as a dialysate pH during therapy. In a preferred embodiment, the pH of the conditioning solution is about 6.5.
An optional final rinse step 108 can be included after conditioning. Storage of the zirconium oxide sorbent module with bicarbonate may increase the risk of microbial growth. The conditioning step 107 can be performed either in the recharger, or alternatively in the dialysis console just prior to use. If the conditioning step 107 is performed on the recharger, the zirconium oxide sorbent module can be rinsed in final rinse step 108 after conditioning to remove the sodium bicarbonate prior to storage. If the conditioning step 107 is performed in the dialysis console, or if the recharged zirconium oxide sorbent module will be immediately reused without storage, the final rinse step 108 can be omitted. In step 109, the method can end and the zirconium oxide sorbent module can be used again in dialysis.
Although the method depicted in
In step 204, the zirconium oxide sorbent module can be filled with a peracetic acid disinfectant. The peracetic acid solution can have any concentration of peracetic acid sufficient to disinfect the zirconium oxide sorbent module, including between 0.5 and 2 wt %. In a preferred embodiment, the peracetic acid solution is 1 wt % in water. The volume of peracetic acid flowed into the zirconium oxide sorbent module should be enough to completely fill the zirconium oxide sorbent module, and can be between 100% to 200% or more of the void volume of the zirconium oxide sorbent module. In a preferred embodiment, a volume of peracetic acid solution flowed into the zirconium oxide sorbent module is 150% of the module void volume.
In step 205, the peracetic acid disinfectant solution can be held in the zirconium oxide sorbent module for a sufficient length of time to ensure complete disinfection of the zirconium oxide sorbent module. The hold time can be any length of time, including between 5 and 30 minutes, between 5 and 10 minutes, between 5 and 15 minutes, between 10 and 20 minutes, between 15 and 30 minutes or between 20 and 30 minutes. The length of the hold time can depend on the temperature of the zirconium oxide sorbent module, and in a preferred embodiment the hold time can be 15 minutes at 22° C. In step 206, the zirconium oxide sorbent module can be rinsed with water, allowing a buffer of water to be present between the peracetic acid solution and the subsequent base solution.
In step 207 a hydroxide base solution can be flowed through the zirconium oxide sorbent module. The hydroxide base solution can be the same solutions described with reference to
An optional rinse step 208 can be included to remove base from the cartridge in cases where conditioning step 209 is not performed on the recharger and the cartridge is stored until the next therapy.
In step 209, the zirconium oxide sorbent module can be conditioned with a sodium bicarbonate solution. The conditioning process of step 209 can use the same solution, volume, and flow rates as the conditioning process described with respect to
In step 304, the mixture of peracetic acid and acetic acid disinfectant solution can be held in the zirconium oxide sorbent module for a sufficient length of time to ensure complete disinfection of the zirconium oxide sorbent module. The hold time can be any length of time, including between 5 and 30 minutes, between 5 and 10 minutes, between 5 and 15 minutes, between 10 and 20 minutes, between 15 and 30 minutes or between 20 and 30 minutes. The length of the hold time can depend on the temperature of the zirconium oxide sorbent module, and in a preferred embodiment the hold time can be 15 minutes at 22° C. In step 305, the zirconium oxide sorbent module can be rinsed with water, allowing a buffer of water to be present between the peracetic acid solution and the subsequent base solution.
In step 306, a hydroxide base solution can be flowed through the zirconium oxide sorbent module. The hydroxide base solution can be the same solutions described with reference to
An optional rinse step 307 can be included to remove base from the cartridge in cases where conditioning step 308 is not performed on the recharger and the cartridge is stored until the next therapy.
In step 308, the zirconium oxide sorbent module can be conditioned with a sodium bicarbonate solution. The conditioning process of step 308 can use the same solution, volume, and flow rates as the conditioning process described with respect to
In step 405, the zirconium oxide sorbent module can be conditioned with a sodium bicarbonate solution. The conditioning process of step 405 can use the same solution, volume, and flow rates as the conditioning process described with respect to
The direction of flow through the zirconium oxide sorbent module during the methods of
The solutions in the disinfectant and acetic acid source 605 and base source 606 can be any concentration, including the concentrations described with reference to
One skilled in the art will understand that various combinations and/or modifications and variations can be made in the described systems and methods depending upon the specific needs for operation. Moreover features illustrated or described as being part of an aspect of the invention may be used in the aspect of the invention, either alone or in combination.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/520,537 filed Jun. 15, 2017, the entire disclosure of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62520537 | Jun 2017 | US |
