WO1994006289A1

WO1994006289A1 - A method of inactivating microbes in blood using iodine

Info

Publication number: WO1994006289A1
Application number: PCT/US1993/004279
Authority: WO
Inventors: Edward Shanbrom
Original assignee: Edward Shanbrom
Priority date: 1992-05-04
Filing date: 1993-05-04
Publication date: 1994-03-31
Also published as: JPH06511016A; EP0622989A1

Abstract

A process of preparing safe biological fluids comprising adding oxidizing iodine to the biological fluid, holding the fluid for a period to permit inactivation of pathogenic microbes, and extracting or precipitating remaining oxidizing iodine from the fluid is disclosed.

Description

A METHOD OF INACTIVATING MICROBES IN BLOOD USING IODINE

Background of the Invention This invention relates to the treatment of biological fluids generally, including such human transfusion blood, serum and plasma and fractions and products thereof, an biological fluids used for diagnostic testing or the production of biologicals for diagnostic tests.

Iodine was officially recognized by the Pharmacopeia of the United States in 1930, also as tincture iodine (tincture of iodine) and linimentum iodi (liniment of iodine). Clinicians and microbiologists described a great number of experimental data and clinical applications. Despite the successes that have been achieved with iodine, it was ascertained early that it also possesses properties unsuitable for practical application.

Although exact details about the killing of a living cell by the I₂ molecule (or one of the reaction products occurring in aqueous solution) are not known, it can be assumed that iodine reacts with basic N-H functions that are parts of some amino acids (e.g., lysine, histidine, arginine) and the bases of nucleotides (adenine, cytosine, and guanine) forming the corresponding N-iododerivatives. By this reaction, important positions for hydrogen bonding are blocked, and a lethal disorder of the protein structure may occur. Iodine oxidizes the S-H group of the amino acid cysteine, through which the connections of protein chains by disulfide (-S-S-) bridges, as an important factor in the synthesis of proteins, are lost. Iodine reacts with the phenolic group of the amino acid tyrosine, forming mono- or diiodo-derivatives. In this case, the bulk of the iodine atom(s) in the ortho position may cause a form of steric hindrance in the hydrogen bonding of the phenolic OH group and with the carbon-carbon double bond (C=C) of the unsaturated fatty acids. This could lead to a change in the physical properties of the lipids and membrane immobilization.

Iodine - polymer complexes, e.g., with poly(vinylpyrrolidone) (PVP), and complexes of iodine with nonionic surfactants, eg, polyethylene glycol mono(nonylphenyl) ether have been used with considerable success. However, use in direct contact with labile biological materials has been limited because either the killing power of iodine is dissipated in the biological material or damages the biological material. Povidone iodine is capable, in certain circumstances, of killing all classes of pathogens encountered in nosocomial infections: gram-positive and gram-negative bacteria, mycobacteria, fungi, yeasts, viruses and protozoa. Most bacteria are killed within 15 to 30 seconds of contact.

Iodine is consumed by proteinaceous substrates and its efficacy as a disinfectant is reduced at certain antiseptic applications. This is due to a reducing effect of the material to be disinfected which leads to the conversion of iodine into non-bactericidal iodide. Thus, not only the reservoir of available iodine is diminished but also the equilibrium of triiodide is influenced as well. Both of these effects cause a decrease in the proportion of free molecular iodine, the actual anti-microbial agent. When povidone-iodine preparations are contaminated with liquid substrata, e.g. blood, etc., there is, in addition, the dilution effect characteristic of povidone-iodine systems which causes an increase in the equilibrium concentration of free molecular iodine. To what extent the latter effect compensates for the other two effects depends on the content of reducing substances. Thus with full blood, a strong decrease of the concentration of free molecular iodine occurs, while, in the presence of plasma, it remains practically unchanged. Durmaz, et al, Mikrobiγol. Bui. 22 (3), 1988 (abstract); Gottardi W, Hγg. Med. 12 (4). 1987. 150-154. Nutrient broth and plasma had little inactivating activity but 1 g hemoglobin inactivated 50 mg of free I; experiments with ¹²⁵I showed that uptake of I by [human] red cells occurred rapidly. Optimal antimicrobial effects in clinical use should be achieved in relatively blood-free situations. Povidone iodine produced a potent and sometimes persistent bactericidal effect towards bacteria on healthy skin. Lacey, R. W., / Appl Bacterwl 46 (3). 1979. 443-450. The bactericidal activity of dilute povidone-iodine solutions is inversely proportional to the concentration of the povidone-iodine solutions and is inhibited to the greatest extent by blood, followed by pus, fat and glove powder. Zamora J L; Surgery (St Louis) 98 (1). 1985. 25-29; Zamora, Am. J. Surgery, 151, p. 400 (1986); see also, Waheed Sheikh, Current Therapeutic Research 40, No. 6, 1096 (1986). Van Den Broek, et al, Antimicrobial Agents and Chemotherapy, 1982,

593-597, suggests that povidone-iodine is bound to cell wall proteins leaving little for interaction with microorganisms in the liquid phase (See, also, Abdullah, et al., Arzneim.-Forsch./Drug Res. 31 (I), Nr. 5, 828). Ninneman et al, J. of Immunol. 81, 1265 (1981) reported that povidone-iodine was absorbed in serum albumin and it is know that povidone-iodine is bound to albumin.

Iodine is used widely in human medicine is the disinfection of skin,

(e.g., the preoperative preparations of the skin, the surgical disinfection of hands, the disinfection of the perineum prior to delivery, and the disinfection of the skin prior to infections and transfusions). Iodine preparations are also used for therapeutic purposes, e.g., the treatment of infected and burned skin but is a strong irritant. Iodophors largely overcome the irritation. Iodine has also been used for the disinfection of medical equipment, such as catgut, catheters, knife blades, ampules, plastic items, rubber goods, brushes, multiple-dose vials, and thermometers. The use of iodine as an aerial disinfectant has been advocated since 1926, and experiments on the disinfection of air have been carried out, mainly during World War II. Aerial disinfection of air-raid shelters with iodine vapors as a prophylactic measure against influenza has been recommended and a "relatively tolerable" concentration of 0.1 mg/ft³ (3.5 mg/m³) was found to be sufficient for a rapid kill of freshly sprayed salivary organisms. Obviously, one is aware of the danger that iodine vapors pose to the respiratory organs, documented by the fact that the maximum allowed concentration of iodine comes to 1.0 mg/m³'

The use of "oxidizing iodine" including "compounds incorporating molecules of oxidizing iodine" e.g. absorbed or grafted on a purified vegetable carbon, as blood-contacting reagents having bactericidal and bacteriostatic action are mentioned in passing in connection with an autotransfuser device in U.S. Patent 4,898,572, Surugue nee Lasnier, et al but without any explanation or elucidation.

Iodine is, thus, an excellent, prompt, effective microbicide with a broad range of action that includes almost all of the important health-related microorganisms, such as enteric bacteria, enteric viruses, bacterial viruses, and protozoan cysts, if the sometimes severe limitations inherent in its use are overcome. Mycobacteria and the spores of bacilli and clostridia can also be killed by iodine. Furthermore, iodine also exhibits a fungicidal and trichomonacidal activity. As to be expected, varying amounts of iodine are necessary to achieve complete disinfection of the different classes or organisms. Within the same class, however, the published data on the disinfecting effect of iodine correspond only to a small extent. In particular, the published killing time of spores and viruses are widely disparate. Various authors have tried to summarize the disinfecting properties of iodine and the other halogens by reviewing the literature and analyzing the existing data. The most important conclusions are: A standard destruction (i.e., a 99.999% kill in 10 minutes at 25° C) of enteric bacteria, amoebic cysts, and enteric viruses requires I₂ residuals of 0.2, 3.5, and 14.6 ppm, respectively. On a weight basis, iodine can inactivate viruses more completely over a wide range of water quality than other halogens. In the presence of organic and inorganic nitrogenous substances, iodine is the cysticide of choice because it does not produce side reactions that interfere with its disinfecting properties. Iodine would require the smallest mg/L dosage compared to chlorine or bromine to "break any water" to provide a free residual. I₂ is 2 to

3 times as cysticidal and 6 times as sporicidal as HOI, while HOI is at least 40 times as virucidal as I₂. This behavior is explained on the one hand by the higher diffusibility of molecular iodine through the cell walls of cysts and spores and on the other hand by the higher oxidizing power of HOI. Gottardi, W. Iodine and Iodine Compounds in DISINFECTION, STERILIZATION, AND PRESERVATION, Third Edition, Block, Seymour S., Ed., Lea & Febiger, Philadelphia, 1983, and the references cited therein provide more details respecting the background discussed above.

Polyvinylpyrrolidone (PVP, Povidone) is manufactured by BASF Aktiengesellschaft, Unternehemensbereich Feincheme, D-6700 Ludwigshaven, Germany and sold under the trademark KOLIDON®. Povidone-iodine products and the preparation of such products are described in U.S. Patents 2,707,701, 2,826,532, and 2,900,305 to Hosmer and Siggia, assigned to GAF Corporation and in a number of GAF Corporation publications; see, e.g. Tableting with Povidone USP (1981) and PVP Polyvinylpyrrolidone (1982).

There is extensive patent literature on the manufacture and use of various iodine-polymer complexes, exemplary of which are: U.S. Patent No.

3,294,765, Hort, et al, 1966 - manufacture of povidone-iodine complex; U.S.

Patent No. 3,468,831, Barabas, et.al., 1969 - graft co-polymers of N-vinyl pyrrolidone; U.S. Patent No. 3,468,832, Barabas, et.al., 1969 - graft co- polymers of N-vinyl pyrrolidone; U.S. Patent No. 3,488,312, Barabas, et. al, 1970 - water-insoluble graft polymer-iodine complexes; U.S. Patent No. 3,689,438, Field, et. al., 1972 - cross-linked polymer-iodine manufacture; U.S. Patent No. 3,907,720, Field, et. al., 1975 - cross-linked polymer-iodine manufacture; U.S. Patent No. 4,017,407, Cantor, et. al., 1977 - solid N-vinyl-

2-pyrrolidone polymer carriers for iodine; U.S. Patent No. 4,128,633, Lorenz et al, 1978 - preparation of PVP-I complex; U.S. Patent No. 4,139,688, Dixon, 1979 - cross-linked vinylpyrrolidone; U.S. Patent No. 4,180,633, Dixon, 1979 - cross-linked vinylpyrrolidone; U.S. Patent No. 4,190,718, Lorenz, et.al., 1980 -increasing molecular weight of polyvinylpyrrolidone.

Under ordinary conditions, PVP is stable as a solid and in solution. The single most attractive property of PVP is its binding capability. This property has permitted utilization in numerous commercial applications. Small quantities of PVP stabilize aqueous emulsions and suspensions, apparently by its absorption as a thin layer on the surface of individual colloidal particles. The single most widely studied and best characterized PVP complex is that of PVP-iodine. For example, hydrogen triiodide forms a complex with PVP that is so stable that there is no appreciable vapor pressure. It is superior to tincture of iodine as a germicide. Various poloxamers (i.e., polyether alcohols) also make effective carriers for iodine (i.e., Prepodyne, Septodyne) that exhibit the same germicidal activity as povidone-iodine. The iodophors are available in a variety of forms, such as a 10% applicator solution, 2% cleansing solution (scrub), aerosol spray, aerosol foam, vaginal gel (for trichonomal and candidal infections) ointment powder, mouthwash, perineal wash, and whirlpool concentrate (all 2%). All iodophors may be used in this invention in some of its various uses and applications and, to the extent that the iodophor is effective and does not injure the material undergoing treatment, are considered generally as equivalents or potential equivalents of povidone iodine. In addition to the risk of transmitting infectious disease via blood or blood products, the growth of bacteria in blood and blood products at various stages of production and processing introduces pyrogens into the blood component or product which must be removed before the product can be used in therapy. Introduction of molecular iodine, e.g. povidone-I₂, at an early stage in processing of blood products greatly reduces or eliminates the pyrogen-load of the ultimate product or fraction.

Generally, this invention is applicable to the treatment of donated blood, products produced from blood, and biological liquids for therapeutic use or the preparation of diagnostic materials, for inactivating virus, bacteria, chlamydia, rickettsia, mycoplasma and other potentially pathogenic microorganisms.

Various medical and blood handling procedures are referred to hereinafter. These are all well-known procedures and steps in these procedures are fully described in the literature. The following references are provided for general background and as sources for detailed reference to the literature as to specific procedures: TECHNICAL MANUAL of the American Association of Blood Bankers, 9th Ed. (1985); HLA TECHNIQUES FOR BLOOD BANKERS, American Association of Blood Bankers (1984); Developments in Biological Standardization, Vols. 1 - 57, S. Karger, Basel; CONICAL IMMUNOCHEMISTRY, The American

Association for Clinical Chemistry; MEDICINE, Vols. 1 - 2, Scientific American, New York; Care of the SURGICAL PATIENT, Vols 1 - 2, Scientific American, New York; CURRENT PROTOCOLS IN MOLECULAR BIOLOGY, Greene Publishing Associates and Wiley- Interscience, John Wiley & Sons, New York.

Most individuals have a high tolerance to iodide; however, some individuals my be sensitive to in vivo introduction of iodine. More importantly, it is desirable to provide biological fluids that are free of, or contain an absolute minimum of, any reagent that may induce side reactions in highly sensitive individuals or in individuals who require repetitive treatment. It is, accordingly, an object of this invention to provide safe biological fluids wherein pathogenic microbes have been inactivated and that are also free of all but traces of iodine.

Summary of the Invention Iodine is added to the liquid biological sample to be freed of pathogenic microorganisms, a period of time, from a minute or two up to 24 hours or more, is permitted to elapse to permit the iodine and then the iodine is removed by separation from the biological fluid by solvent extraction or precipitation and filtration or centrifugation. Safe transfusion blood, or blood substitute, is manufactured by removing a substantial portion of blood plasma or serum from whole blood. In the case of plasma removal, a blood cell concentrate remains. If serum is separated directly from blood, cells from another unit of blood may be used. The plasma or serum is passed into contact with a solid source of available oxidizing iodine for inactivating pathogenic microbes in the blood and for transferring an effective amount of oxidizing iodine, from about 0.01% by weight to five percent by weight, into the plasma or serum to inactivate pathogenic microbes in both the plasma or serum and in the blood cell concentrate. The next step comprises reconstituting the whole blood by mixing the iodized plasma with the blood cell concentrate or reconstituting a blood substitute by mixing the iodized serum with the blood cell concentrate, the available oxidizing iodine in the plasma or serum being from about 0.01% to about five percent by weight of the serum and sufficient to inactivate substantially all pathogenic microbes in the blood cell concentrate. Optionally, other viricidal and/or biocidal compounds may be added to the serum or to the reconstituted blood to enhance the viral inactivation and interfere with the virus replication in the cells. After a suitable period of time, from a few minutes to an hour or more, the reconstituted blood is contacted with a solvent for iodine that has no effect or minimal effect on blood cells and the hydrophilic components of the blood. Normal alkane, e.g. n-heptane, is a suitable extraction solvent for removing oxidizing iodine from the blood. Of course, iodine that has been reduced to iodide will remain, largely, in the aqueous blood phase. Other extraction solvents include analogous homolog of heptane and vegetable oils such as soy bean oil, cotton seed oil, corn oil, etc. Any hydrophobic solvent for iodine that is essentially inert biologically and has sufficient density difference from water and respecting which water has a high enough interfacial tension to form a clean separation from the aqueous phase may be used as the solvent. Iodine may also be removed by adding starch solution and removing the starch-iodine precipitate that forms, or by contacting the plasma with cross-linked povidone. Safe transfusion plasma is manufactured by passing the plasma into contact with a solid source of available oxidizing iodine, or otherwise introducing oxidizing iodine into the plasma, for inactivating pathogenic microbes in the plasma and for transferring an effective amount of oxidizing iodine, from about 0.01% by weight to five percent by weight, into the plasma to activate pathogenic microbes in the plasma. After a suitable period of time, from a

minutes to an hour or more, the plasma is contacted with a solvent for iodine that has no effect or minimal effect on plasma and the hydrophilic components. Normal alkane, e.g. n-heptane, is a suitable extraction solvent for removing oxidizing iodine from the blood. Of course, iodine that has been reduced to iodide will remain, largely, in the aqueous phase. Other extraction solvents include analogous homolog of heptane and vegetable oils such as soy bean oil, cotton seed oil, corn oil, etc. Any hydrophobic solvent for iodine that is essentially inert biologically and has sufficient density difference from water and respecting which water has a high enough interfacial tension to form a clean separation from the aqueous phase may be used as the solvent.

Safe transfusion serum is manufactured by passing the serum into contact with a solid source of available oxidizing iodine, or otherwise introducing oxidizing iodine into the serum, for inactivating pathogenic microbes in the serum and for transferring an effective amount of oxidizing iodine, from about 0.01% by weight to five percent by weight, into the serum to activate pathogenic microbes in the serum. After a suitable period of time, from a few minutes to an hour or more, the serum is contacted with a solvent for iodine that has no effect or minimal effect on serum and the hydrophilic components. Normal alkane, e.g. n-heptane, is a suitable extraction solvent for removing oxidizing iodine from the blood. Of course, iodine that has been reduced to iodide will remain, largely, in the aqueous phase. Other extraction solvents include analogous homolog of heptane and vegetable oils such as soy bean oil, cotton seed oil, corn oil, etc. Any hydrophobic solvent for iodine that is essentially inert biologically and has sufficient density difference from water and respecting which water has a high enough interfacial tension to form a clean separation from the aqueous phase may be used as the solvent.

Alternatively, plasma or other biological liquid can be freed of iodine by addition of starch solution containing dissolved starch in an amount sufficient to bind all of the added iodine or by contacting the plasma, serum or other liquid with solid, cross-linked polyvinyl povidone which adsorbs the iodine forming a PVP-iodine complex, then removing the solid cross-linked polyvinyl pyrrolidone, including the iodine complexed therewith.

Other biological liquids are treated in an analogous manner. Description of the Preferred Embodiments The following is given as a basic, exemplary method of carrying out the present invention. It will be understood that the present technique can be adapted to integrating the present invention into overall blood collection and handling technique, that additional steps may be added, and that many variations are possible within the scope of the invention. Whole Blood A unit of transfusion quality blood is separated into plasma and blood cell concentrate. This may be accomplished by compressing the blood through a filter to express a substantial amount of the plasma from the container leaving a blood cell concentrate, by centrifuging the blood lightly and decanting the plasma, or in any other way. This step, separating a substantial amount of the plasma from the blood cell concentrate can be carried out using any convenient manipulation(s). It is not necessary that all of the plasma be separated; however, best results are achieved when substantially all of the plasma not interstitially trapped between the cells of the cell concentrate is removed. The plasma is then contacted with a solid source of oxidizing iodine that holds the iodine loosely enough to permit some of the iodine to enter into the plasma. One convenient way of carrying out the invention is to express plasma through a bed (filter) of polymer-iodine particles. This provides contact with a solid source of oxidizing iodine and helps effect a separation of the plasma from the cell concentrate. Any of several forms of solid povidone- iodine or other polymer-iodine complex is a suitable form of such iodine.

Whole Blood Substitute A unit of transfusion quality blood is separated into plasma and blood cell concentrate and the plasma is coagulated to produce serum. This separation may be accomplished by compressing the blood through a filter to express a substantial amount of the plasma from the container leaving a blood cell concentrate, by centrifuging the blood lightly and decanting the plasma, or in any other way. This step, separating a substantial amount of the plasma from the blood cell concentrate can be carried out using any convenient manipulation(s). It is not necessary that all of the plasma be separated; however, best results are achieved when substantially all of the plasma not interstitially trapped between the cells of the cell concentrate is removed. If two units of blood are available, one unit may be coagulated and the serum used to reconstitute blood substitute.

The serum is then contacted with a solid source of oxidizing iodine that holds the iodine loosely enough to permit some of the iodine to enter into the serum. This provides contact with a solid source of oxidizing iodine. Any of several forms of solid povidone-iodine or other polymer-iodine complex are suitable forms of such iodine. Cross-linked povidone iodine and polymer- iodine complexes have been known for many years. Solid polyvinylpyrrolidone-iodine complexes are described, inter alia, by: Barabas, et.al., 1969 - graft co-polymers of N-vinyl pyrrolidone; U.S. Patent No. 3,468,832; Barabas, et.al., 1969 - graft co-polymers of N-vinyl pyrrolidone; Barabas, et al., 1970, U.S. Patent No. 3,488,312 - water-insoluble graft polymer-iodine complexes; Field et al, 1972, U.S. Patent No. 3,689,438 - cross-linked polymer-iodine manufacture; Field, et. al., 1975 - U.S. Patent No.

3,907,720 - cross-linked polymer-iodine manufacture; Cantor, et. al., 1977, U.S. Patent No. 4,017,407 - solid N-vinyl-2-pyrrolidone polymer carriers for iodine; Lorenz et al, 1978, U.S. Patent No. 4,128,633 - preparation of PVP-I complex; Dixon, 1979, U.S. Patent No. 4,139,688 - cross-linked vinylpyrrolidone; Dixon, 1979, U.S. Patent No. 4,180,633 - cross-linked vinylpyrrolidone; Lorenz, et.al., 1980, U.S. Patent No. 4,190,718 -increasing molecular weight of polyvinylpyrrolidone. Other polymer-iodine complexes are described, inter alia, by Rosenblatt, 1991, U.S. Patent 5,071,648 - polyvinyl alcohol-iodine; and Fiore, et al., 1990, U.S. Patent 4915839 - process for surface modifying a microporous membrane; nylon fiber used for microfiltration of biological liquids.

The plasma and the blood cell concentrate are reconstituted to form whole blood or the serum and blood cell concentrate are reconstituted to form a blood substitute. Residual iodine in the plasma, or serum, is present in a sufficient amount, from 0.001 to five percent, typically from 0.1 to 1 percent, by weight, in the plasma, or serum, to kill or inactivate all extracellular virus in the blood cell concentrate and substantially all or all intracellular virus by penetration into the cell. A brief reaction period is required after the reconstitution of the whole blood. A minimum of about two minutes is necessary, and at least about 15 minutes is desirable, before extracting iodine from the blood to permit the iodine to inactivate the pathogenic microbes in the blood.

After a suitable period after the addition of the iodine has been added the blood is then gently mixed with a solvent for iodine that is substantially inert to blood. N-heptane is a good solvent for iodine and has minimal effect, on short exposure, to blood and blood cells. Close n-alkane analogs and vegetable oils may also be used. Soy bean oil, cotton seed oil, corn oil, etc. are generally biologically inert as to blood and blood cells and are also suitable solvents for iodine. The solvent extraction may be carried out in any suitable vessel that will permit intimate mixing of the blood and solvent and decantation of the hydrophobic phase from the top or withdrawal of the blood from the bottom. Alternatively, the blood substitute may be contacted with solid particles of cross-linked povidone which complexes with the iodine. The particles are removed by a suitable filter, settling or mild centrifugation. The process results in transfusion quality whole blood that is safe, being free of pathogenic microbes, and which is also free of any added chemicals except for iodide (resulting from reduction of the iodine).

If further assurance of total conversion of iodine to iodide is desired, the addition of biologically compatible reducing substances, e.g. reducing sugars, ascorbic acid or ascorbate, sodium sulfite, etc. may be added. It is, however, well known and firmly established that iodide is well- tolerated in vivo by nearly all human subjects. The present invention, therefore, obviates objections to the introduction of povidone or other polymeric substances into the blood stream of the patient. Blood Plasma. Serum and Other Biological Liquids Plasma, serum, or other biological liquid, is, preferably, passed through a filter or column that constitutes a solid source of oxidizing iodine that holds the iodine loosely enough to permit some of the iodine to enter into the liquid. Any other means of introducing oxidizing iodine into the liquid with introduction of undesirable carriers or other liquids may be used as well. Any of several forms of solid povidone-iodine or other polymer-iodine complex is a suitable form of such iodine. Cross-linked povidone iodine and polymer-iodine complexes as described above are quite suitable.

Alternatively, plasma, serum or other biological liquid can be freed of iodine by addition of starch solution containing dissolved starch in an amount sufficient to bind all of the added iodine. Iodine that has not been reduced, I₃, binds very firmly to starch, forming a blue precipitate that can be separated by filtration or centrifugation from the liquid. Quite surprisingly, the starch- iodine complex retains iodine's biocidal properties. Work to date suggests that the virucidal activity of iodine is enhanced when starch is added; however, it has not yet been determined if this result is because of greater virucidal activity of the complexed starch or the additive effects of a transitional residue of iodine in solution and the biocidal effect of starch-iodine. Alternatively, dry starch powder can be added followed by separation of the well-known blue starch-I₃ complex and the unreacted starch by filtration. It is, however, regarded as preferable to minimize the amount of starch added, even though starch is entirely compatible in the blood stream. The same procedure can be used, somewhat less satisfactorily, with reconstituted blood; however, the blood must be reconstituted using the cell-containing fractions after centrifugation. In another alternative, the blood substitute may be contacted with solid particles of cross-linked povidone which complexes with the iodine. The particles are removed by a suitable filter, settling or mild centrifugation.

The process results in plasma, serum, or other biological fluid, that is safe, being free of pathogenic microbes, and which is also free of any added chemicals except for iodide (resulting from reduction of the iodine).

If further assurance of total conversion of iodine to iodide is desired, the addition of biologically compatible reducing substances, e.g. reducing sugars, ascorbic acid or ascorbate, sodium sulfite, etc. may be added. Pathogenic microbes that are inactivated in accordance with this invention include virus, bacteria, chlamydia, rickettsia, mycoplasma and other potentially pathogenic microorganisms.

Data in the above identified co-pending applications establish the biocidal and virucidal efficacy of iodine. Practical Application

This invention is useful in the preparation of safe transfusion blood and biological liquids.

Claims

WHAT IS CLAIMED IS:

1. A process of preparing safe human transfusion blood comprising the steps of separating whole human blood into cell concentrate and plasma, adding oxidizing iodine to the plasma in an amount equivalent to at least 0.001 percent by weight of the blood sufficient to inactivate substantially all microbes in the plasma and cell concentrate, reconstituting whole blood from the thus treated plasma and the cell concentrate, holding the reconstituted blood for a period of greater than about two minutes and solvent extracting the reconstituted blood with a hydrophobic biologically compatible iodine solvent before transfusing the same into a patient.

2. The process of Claim 1 wherein adding oxidizing iodine comprises passing the plasma into contact with solid polymer-iodine complex to add oxidizing iodine.

3. A process of preparing plasma or serum safe for transfusion into a patient comprising the steps of adding oxidizing iodine to said plasma or serum in an amount equivalent to at least 0.001 percent by weight sufficient to inactivate substantially all microbes in such plasma or serum, holding the plasma or serum for a period of greater than about two minutes and solvent thereafter extracting the biological fluid with a hydrophobic biologically compatible iodine solvent.

4. The process of Claim 3 wherein adding oxidizing iodine comprises passing the plasma or serum into contact with solid polymer-iodine complex to add oxidizing iodine.

5. A process of preparing plasma or serum safe for transfusion comprising the steps of adding oxidizing iodine to said plasma or serum in an amount equivalent to at least 0.001 percent by weight sufficient to inactivate substantially all microbes in such plasma or serum, holding the plasma or serum for a period of greater than about two minutes and solvent thereafter reacting the plasma or serum with starch and separating the resulting starch iodine precipitate from the plasma or serum.

6. The process of Claim 5 wherein adding oxidizing iodine comprises passing the plasma or serum into contact with solid polymer-iodine complex to add oxidizing iodine.

7. A process of preparing human transfusion blood substitute comprising the steps of separating whole human blood into cell concentrate and producing serum from the plasma in the blood, adding oxidizing iodine to the serum in an amount equivalent to at least 0.001 percent by weight of the blood sufficient to inactivate substantially all microbes in the serum and cell concentrate, reconstituting blood substitute from the thus treated serum and the cell concentrate, holding the reconstituted blood substitute for a period of greater than about two minutes and solvent extracting the reconstituted blood with a hydrophobic biologically compatible iodine solvent before transfusing the same into a patient.

7. The process of Claim 8 wherein adding oxidizing iodine comprises passing the serum into contact with solid polymer-iodine complex to add oxidizing iodine.

8. A process of removing iodine from plasma, serum or other biological fluid comprising reacting the liquid with a solution starch and separating the resulting starch-iodine precipitate from the liquid.

9. A process of removing iodine from plasma, serum or other biological fluid comprising contacting such fluid with solid particles of cross-linked povidone which complexes with the iodine and then separating such particles from such fluid.