NON-HEMOLYZING BLOOD FILTER AND METHODS FOR FILTERING BLOOD WITHOUT HEMOLYSIS

Abstract

An article, system, and method is provided for the filtration of blood wherein the blood is removed, contacted with a filter substrate operatively associated with a filter structure, and the filtered blood is subsequently returned to a receiver. Methods for removing iron from the liquid fraction of blood and for determining whether a substrate is capable of selectively retaining 2,2-dipyridyl (DP)-Fe.sup.2+ complexes are also disclosed.

Claims

1. A system for filtering blood comprising: a vessel configured to selectively hold a volume of blood; more than one substrate configured to chemically filter the blood and blood components, wherein the more than one substrate are arranged in series at an outlet of the vessel; and at least one structure configured to support said more than one substrate, wherein the at least one substrate is configured to selectively retain 2,2-dipyridyl (DP)-Fe.sup.2+ complexes but is permeable to Arsenazo III-Ca.sup.2+ complexes, and wherein said at least one structure has a pore size between 0.0001 micron to 20 micron.

2. The system of claim 1, wherein said more than one substrate is independently: a chelating agent; a styrene-divinylbenzene co-polymer containing iminodiacetic acid groups; polyphenols; phytates; ascorbic acid derivatives; polymeric hydroxamic acid; derivatives/hydrogels/resins, or chemical modifications of existing oral chelating drugsdeferoxamine, deferiprone, and deferasirox, or combinations thereof.

3. The system of claim 1 wherein said more than one substrate is positioned in-line in a blood transfusion system.

4. The system of claim 3 wherein blood, in the blood transfusion system, is caused to make contact with said more than one substrate by gravitational movement of blood, mechanical movement of blood, or a combination thereof.

Description

BRIEF DESCRIPTIONS OF THE DRAWINGS

[0019] FIG. 1 illustrates proposed storage lesions that red blood cells can undergo with time, and is reprinted from Buehler, P. W., et al., Blood aging, safety, and transfusion: capturing the radical menace, Antioxid. Redox Signal. 14(9):1713-28 (2011).

[0020] FIG. 2 demonstrates that Chelex? 100 resin retains DP-Fe.sup.2+.

[0021] FIG. 3 demonstrates that Chelex? 100 resin efficiently retains 1 mM DP-Fe.sup.2+, but not 1 mM Arsenazo III-Ca.sup.2+.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0022] Disclosed is an article, system, and method that decreases the overall burden of iron overload and other damaging components in blood transfusions. Without being tied to any particular theory or result, it is believed that binding and separating the dangerous components that trigger iron overload by removing them once they come into contact with the active agents of the device is disclosed.

[0023] Based on a long-felt but unmet need to remove dangerous components, disclosed is a chelation-based blood filter that will function in removing free or suspended dangerous elements and compounds before it enters into patient body and causes harm to the vital organs and other complications. This filter is capable of being included in the blood transfusion process at two stages: after the processing of blood in the blood collection centers and at the end stage just before blood is transfused to subject. Disclosed is a non-hemolysing filter that will remove (i) damaging components, and (ii) damaged red blood cells.

[0024] Disclosed is filter that can be round/spherical in shape, integrated or separated into a single or multiple compartments, in series to the outlet of blood bag going to patients/inserted in blood bag during storage, made of biocompatible/new material, using chelating chemicals, immobilized/suspended, sandwiched/directly coming in contact with blood, where blood will flow over or flow through the filter and damaging components will be entrapped in the filter.

[0025] Without being tied to any particular theory or result, any of the following components in any combinations are contemplated being used in the disclosed article: alloys, ceramics, cellulose, plastic/polymers, thermoplastics, thermosets, elastomers, homopolymers, copolymers, polymer blends, polyvinylchloride, polyethelene, polypropylene, cycloolefin polymers/copolymers, polystyrene, acrylics, polycarbonates, polyurethanes, polyacetals, polyesters, polylactic acid copolyesters, polyamides, polysulfones, polyimides, polyamide-imides, polyphenylene sulfide, polyether ether ketones, liquid crystalline polymers, nitrocellulose, fibrin, nanoplastics, nylon, nanoparticles, fluoropolymers, styrenics, silicones, and biopolymers. These components can be coated, non-coated, or both, hydrophobic, hydrophilic, or both, and these plastics can be used in any combination with each other. Additionally, any of these components can be mixed with nano additives, plastic additives, or drugs.

[0026] Disclosed are custom membranes including, but not limited to: alloys, ceramics, mixed cellulose ester, polyesteramide, polyfluortetraethylene, polyethersolphone, polyvinylidene fluoride, polypropylene, cellulose acetate, glass fiber, quartz fiber polystyrene, polyether urethane, sulfated polyethylene, hydroxyathyl methacrylate, polylactic acid polyethylene glycol polycarbonate. These custom membranes may be coated and non-coated, hydrophillic, hydrophobic, or dual sided, or come in one or more layers. These materials can be used in any combination with each other.

[0027] Also disclosed is one or more chemical chelation components. Further disclosed is Chelex?, which is a chelating material from Bio-Rad Laboratories, Inc. capable of purifying other compounds via ion exchange. It is noteworthy for its ability to bind transition metal ions. Chelex? is a styrene-divinylbenzene co-polymer containing iminodiacetic acid groups. Other disclosed chemicals include polyphenols, phytates, ascorbic acid derivatives, polymeric hydroxamic acid derivatives/hydrogels/resins, or even chemical modifications of already existing oral chelating drugs: deferoxamine, defferiprone, and defarisirox.

[0028] Any chemical, compound, substrate, or combinations thereof are operatively associated with the disclosed filter. The association includes any type of fixation, imbedding or attachment of the substrate to the filter in a manner such that the chemical components are in direct contact with blood being filtered in the present invention.

[0029] Disclosed is chemical immobilization. Additional disclosures include, but are not limited to and/or physical adsorption, entrapment, absorption, immobilization on beads/resin, and integration with plastics, membranes, biocompatible polymers, in existing tubing, or combinations thereof.

[0030] Also disclosed is a construction and arrangement that removes dangerous elements form the blood without leaching anything or changing the pH/chemistry or morphology of the blood cells. The chemical is immobilized with a unique filter that optimizes the blood flow through rate in which dangerous components from the blood are extracted. The configurations of the filter range from circular to oval to rectangular to square to and any shape that has 3 or more sides. Furthermore, the porosity range of the filter membrane can be from 0.0001 microns to 20 microns.

[0031] Additionally disclosed is a configuration in order to filter the red blood cells on the basis of size whereby red blood cells of particular sizes are removed.

[0032] Substances for separation are, of course, well known in the art. Some substances separate on the basis of ion exchange, in which ions of one charge are retained on the substances. An example of an ion exchange substance is Chelex?, which is a styrene-divinylbenzene co-polymer containing iminodiacetic acid groups. Chelex? is well known in the art as a substance for separation based on ion exchange, but disclosed herein for the first Lime is that Chelex? is capable of selectively retaining DP-iron complexes. See Chelex? 100 and Chelex 20 Chelating Ion Exchange Resin Instruction Manual, Bio-Rad Laboratories, Hercules, Calif. (LIT200 Rev B). Also disclosed for the first time is that Chelex? does not bind protein-calcium ion complexes, thereby establishing selectivity of protein-metal ion binding.

[0033] Containers for these substances for separation typically have a single lumen, but the diameter of the lumen of one end of the container is typically smaller than the diameter of the lumen of the other end of the container. In other words, these containers are/have at least one tapering section. Other typical containers are columns, but these columns are not sized for blood. The containers disclosed herein are not tapered and are sized for blood.

[0034] As used herein, the term free iron refers to iron not encapsulated within intact erythrocytes. Free iron can include Fe.sup.3+ ions, Fe.sup.2+ ions, hemoglobin, heme, and 2,2-dipyrydyl-Fe.sup.2+. As also used herein, the term drug-chelated iron refers to complexes of deferoxamine, defferiprone, and defarisirox with iron ions.

EXAMPLES

[0035] Some non-limiting examples follow.

Example 1

[0036] In this example, the ability of Chelex? 100 resin to retain iron ions, iron complexes, and an iron complex in the presence of calcium ions was examined. Approximately 0.5 g of Chelex? 100 resin (149 ?m particle size; Bio-Rad Laboratories, Inc., Hercules, Calif.) was packed in a filter tube with a 40 ?m pore size bed. Solutions of 1 mM FeCl.sub.3, 1 mM FeCl.sub.2, 1 mM 2,2-dipyrydyl (DP)-Fe.sup.2+, and 1 mM deferoxamine (DFO)-Fe.sup.3+ were prepared in water (Sigma-Aldrich, St. Louis, Mo.). A solution of 1 mM DP-Fe.sup.2+ and 10 mM CaCl.sub.2 (Sigma-Aldrich, St. Louis, Mo.) in water was also prepared.

[0037] FIG. 2 demonstrates that Chelex? 100 resin retains DP-Fe.sup.2+. The right-hand tube in FIG. 2 is a 1 mM solution of DP-Fe.sup.2+. This solution was filtered through the Chelex? 100 resin filter tube at a rate of 4 ml/min and a contact time of fifteen seconds. The column on the far left of FIG. 2 demonstrates that the Chelex? 100 resin retains DP-Fe.sup.2+. After passing 93 ml of a 1 mM solution of DP-Fe.sup.2+ through 0.72 g of Chelex 100 resin, the filtrate began showing a slight pink color, indicating saturation (left-hand tube).

[0038] The capacities of Chelex? 100 resin to remove free Fe.sup.3+, Fe.sup.2+, DP-Fe.sup.2?, and DFO-Fe.sup.3+ complexes were titrated by adding measured amounts of solutions of the complexes until color appeared in the filtrates. The capacities of Chelex? 100 resin to retain each component are expressed below:

TABLE-US-00001 Amount of iron preparation retained Preparation (mg/g Chelex? 100 resin) Fe.sup.3+ 103.7 Fe.sup.2+ 69.1 DFO-Fe.sup.3+ 10.1 1 mM DP-Fe.sup.2+ 7.4 1 mM DP-Fe.sup.2+ 4.8 and 10 mM CaCl.sub.2
Thus, Chelex? 100 resin captures and retains iron even in the presence of strong iron chelators.

[0039] It is calculated that one gram of Chelex? 100 resin is sufficient to remove all hemoglobin-derived iron compounds in one unit of packed red blood cells. One unit of packed red blood cells contains approximately four-hundred milliliters of blood with hemoglobin levels at 150 grams per liter. Therefore, one unit of packed red blood cells contains approximately sixty grams of hemoglobin (150 g/L?0.4 L=60 g). Because the molecular weight of hemoglobin is approximately 64,500 daltons, one unit of packed red blood cells contains approximately 0.93 millimoles of hemoglobin (60 g?64,500 Da?0.93 millimoles).

[0040] And, one molecule of hemoglobin contains four iron ions, each with a molecular weight of approximately fifty-six daltons. Therefore, there is approximately two-hundred and eight milligrams of iron in one unit of packed red blood cells (0.93 millimoles?4 iron ions?fifty-six daltons?208 mg iron ions). Assuming a two percent hemolysis rate in any given unit of packed red blood cells, the amount of free iron in the packed red blood cell unit is approximately 4.2 milligrams. (208 mg iron ions?2%=4.2 mg iron ions). Because Chelex? 100 resin was found to retain at least 4.8 milligrams of iron ions per gram, one gram of Chelex? 100 resin is calculated to be sufficient to remove all hemoglobin-derived iron compounds in one unit of packed red blood cells.

Example 2

[0041] In this example, the relative selectivity of Chelex? 100 resin to retain iron complexes or calcium complexes was examined. Preparations of 2 mM DP-Fe.sup.2+ and 2 mM Arsenazo III-Ca.sup.2+ (Sigma-Aldrich, St. Louis, Mo.) in water were mixed in equal parts. FIG. 3 demonstrates that Chelex? 100 resin efficiently retains 1 mM DP-Fe.sup.2+, but not 1 mM Arsenazo III-Ca.sup.2+. Specifically, cuvette 2 contains the mixture of 1 mM DP-Fe.sup.2+ and 1 mM Arsenazo III-Ca.sup.2+ before the mixture was filtered through Chelex? 100 resin. Cuvette 1 contains the filtrate; note that the filtrate has the approximate color of a 1 mM Arsenazo III-Ca.sup.2+ solution in water. Cuvette 3 contains a 1 mM DP-Fe.sup.2+ solution in water before the mixture was filtered through Chelex? 100 resin. Cuvette 4 contains the filtrate; note that the filtrate is approximately colorless.

[0042] While the invention has been described in its preferred form or embodiment with some degree of particularity, it is understood that this description has been given only by way of example and that numerous changes in the details of construction, fabrication, and use, including the combination and arrangement of parts, may be made without departing from the spirit and scope of the invention.