JPS637788B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION BACKGROUND OF THE INVENTION Technical Field The present invention relates to a method of manufacturing an artificial organ. More specifically, the present invention relates to a method for manufacturing so-called adsorption type artificial organs used as artificial kidneys, artificial livers, etc. Prior Art So-called adsorption type artificial organs are used as artificial kidneys, artificial livers, and the like. These artificial organs contain an adsorbent and are used in an extracorporeal circulation circuit, and the adsorbent is brought into direct contact with blood or plasma to adsorb toxic or waste substances in the blood or plasma. It is to be removed. Activated carbon, ion exchange resins, zeolites, activated clay, non-ion exchange resins, and the like are used as adsorbents built into such artificial organs.
However, when these adsorbents are brought into direct contact with blood or plasma, fine particles are generated and released from the adsorbent surface or within its micropores, which are introduced into the body and cause embolism in capillaries or accumulate in tissues. In addition, the adhesion of fine particles may cause platelet destruction. In order to prevent such inconveniences associated with the generation of fine particles from the adsorbent, the adsorbent is washed in advance to remove fine particles before being filled. Conventional methods of cleaning adsorbents include using water or physiological saline as the cleaning solution, washing with continuous water flow of the cleaning solution, and repeating stirring and decantation in the cleaning solution. Alternatively, ultrasonic cleaning is performed in a cleaning solution. However, none of the conventional cleaning methods can sufficiently reduce the amount of microparticles released. For this reason, the surface of the adsorbent after washing is usually coated with a hydrophilic substance instead of being used as is. For example, especially when activated carbon is used as an adsorbent, its surface is coated with a hydrophilic polymer film such as collodion, hydrogel, cellulose, etc. after cleaning. However, surface-coated adsorbents lead to a decrease in adsorption capacity, which increases the amount of adsorbent used.
As an artificial organ, it is large and requires a large amount of priming, which increases the burden on the patient during extracorporeal circulation. In addition, some organic solvent used during coating formation may remain, and this may be eluted during autoclave sterilization or long-term storage, which may have an adverse effect on living organisms. Separately, the adsorbent after cleaning is fixed on an adhesive tape to prevent particulates from leaking out. This method has a high adsorption capacity because it does not have a coating on its surface, but it has the fatal disadvantage of complicating the structure of the artificial organ and increasing cost. There is also a risk of the adhesive leaching out. Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances. The main objective is to provide a method for manufacturing artificial organs in which the amount of microparticles released into blood or plasma is significantly reduced compared to when using conventional cleaning methods. . A second object of the present invention is to provide a method for manufacturing an artificial organ that does not require coating the adsorbent surface after cleaning and does not cause a decrease in the adsorption ability of the adsorbent due to coating formation. A third object of the present invention is to provide a method for manufacturing an artificial organ that can be easily implemented at low cost by using an adsorbent cleaning step that can be performed with a simple configuration. Other objects of the invention will become apparent from the description below. The inventors of the present invention have conducted extensive studies to achieve such an objective. As a result, the following findings were obtained. That is, from a chemical standpoint, blood and plasma are high-protein solutions, and solutions with strong surfactant and protective colloid effects. On the other hand, the cleaning liquid conventionally used for cleaning adsorbents for artificial organs is distilled water or physiological saline, as described above. and,
These have no surfactant effect. Therefore, if we fill a container with an adsorbent that has been washed with a cleaning solution that does not have a surfactant effect and contact it with blood that has a surfactant action, the hydrophobic particles that were present on the surface of the adsorbent even after washing will be removed. It is conceivable that a situation may occur in which the sexual particles are efficiently washed away by blood, so to speak. We have come to the conclusion that this is the reason why conventional cleaning methods cannot sufficiently reduce the amount of fine particles generated and released. Based on these considerations, the inventors of the present invention came up with the idea that if a solution having a surfactant effect or a protective colloid effect is used as a cleaning liquid, the effect of cleaning particles would be significantly improved. Among these solutions, when we actually cleaned the adsorbent using an aqueous solution of an organic colloid that is harmless to living organisms, we found that the cleaning effect was extremely high, and the above objectives were effectively achieved. This knowledge led us to complete the present invention. The method for manufacturing artificial organs in which the container is filled with a washed adsorbent is to achieve the above purpose by using a polysaccharide material with an average molecular weight of 4000 or more that is harmless to living organisms and has a surface-active effect and a protective colloid effect. An artificial method in which the adsorbent is washed in an aqueous solution of a roid compound or polypeptide compound by applying ultrasonic waves, then washed with water or physiological saline, and then filled into a container without drying. This is a method for producing organs. DETAILED DESCRIPTION OF THE INVENTION The manufacturing method of the present invention will be described in detail below. In the present invention, the adsorbent used may be activated carbon, zeolite, activated clay, ion exchange resin, non-ion exchange resin, etc., and there are no particular restrictions on its shape, size, etc. This is because the amount of microparticles released is reduced regardless of which adsorbent is used. Among these various adsorbents, it is preferable to use activated carbon, especially petroleum pit activated carbon made from petroleum pit. Such petroleum pitch-based activated carbon usually has approximately spherical particles and has a large adsorption capacity, and artificial organs containing it exhibit excellent performance. In addition, petroleum pitch-based activated carbon has high hardness and smooth surface shape, and generates fewer particles compared to other activated carbons, and the cleaning method of the present invention realizes an artificial organ with an extremely small amount of particles released. It is something to do. The amount of microparticles released becomes even smaller when the petroleum pit activated carbon is subjected to ultrasonic cleaning in a cleaning solution described below. Note that the petroleum pit activated carbon to be used usually has a particle size of about 0.1 to 1 mm, and commercially available carbon can also be used as is. It can also be used as Furthermore, the petroleum pitch activated carbon used may be subjected to heat treatment or the like in a predetermined atmosphere in advance. According to the present invention, such an adsorbent is cleaned in a predetermined cleaning liquid without previously forming a film of hydrophilic polymer or the like on its surface. The cleaning liquid used here is an aqueous solution of an organic colloid that has both a surfactant effect and a protective colloid effect and is harmless to living organisms. In other words, the organic compound contained as a solute in the cleaning liquid is present in water as an organic colloid, and this organic colloid is a hydrophobic fine particle colloid present on the surface of the adsorbent in water as a cleaning liquid solvent. In addition to enveloping and stabilizing it, it also adsorbs to the surface of this hydrophobic microparticle colloid and adjusts its interfacial phenomena. On the other hand, even if such an aqueous organic colloid solution is used, it is a matter of course that the organic colloid aqueous solution must be harmless to living organisms in view of the biocompatibility of artificial organs. For example, sodium alkylbenzene sulfonate, which is widely used as a synthetic detergent, has surfactant effects and protective colloid effects, but it also has hemolytic toxicity and is adsorbed to adsorbents, especially activated carbon, which can damage the living body of artificial organs. This would significantly impair suitability. In this way, the compounds constituting the organic colloid must be selected from among those that have been confirmed to be harmless to living organisms when introduced into the blood, and in particular, to be non-toxic, pyrogenic, and non-hemolytic. Must be. As a compound constituting such an organic colloid, a polysaccharoid compound or a polypeptide compound is used. In this case, polysaccharoid compounds are particularly preferably polysaccharides and derivatives thereof, and particularly preferred specific compound examples include starch, dextran, levan, pectic acid, alginic acid, Heparin, chondroitin sulfate, etc.; and examples of polysaccharide derivatives include hydroxyethyl starch, methylcellulose, carboxymethylcellulose, etc. The polypeptide compound is preferably a natural or synthetic polypeptide or a derivative thereof. Particularly preferable specific compound examples include albumin, etc. as a natural polypeptide; α, α, etc. as a synthetic polypeptide; β-poly(2
-Hydroxyethyl)-D,L-aspartic acid amide, etc. As natural polypeptide derivatives, oxypolygelatin, modified gelatin solution (modified
fluid gelatin), urea-crosslinked gelatin, and the like. The average molecular weight of the compound constituting such an organic colloid must be 4000 or more. The compounds in the above-mentioned preferred compound group are high molecular compounds, and most of them have such an average molecular weight. If the average molecular weight of the compound constituting the organic colloid is 4000 or less, the adsorption ability of the adsorbent may deteriorate to some extent after washing. On the other hand, the average molecular weight is 4000 or more, more preferably
If it is 5000 or more, the deterioration of adsorption capacity after washing will be sufficiently small. Note that two or more of these compounds can be used in combination, but when two or more types are used in combination, the average molecular weight of the whole may be 4000 or more. These compounds, two or more of them if necessary, are dissolved as an organic colloid. in this case,
Water is used as a solvent for the cleaning solution, and the water as a solvent may further contain other solutes as long as the effects of the present invention are not diminished. For this reason, the organic colloid is generally dissolved in distilled water or physiological saline. On the other hand, the concentration of at least one compound dissolved as such an organic colloid is not particularly limited. However, the concentration is usually about 0.05 to 10%, more preferably about 0.1 to 5%, expressed as a percentage of the total weight (g) of the compound per 1 dl of solvent (water). To clean the adsorbent using the cleaning liquid as detailed above, you can wash it in running water of the cleaning liquid,
There are various methods such as repeating decantation using a washing liquid. However, in order to further reduce the amount of microparticles leaking into the blood during use of an artificial organ, it is necessary to perform cleaning by ultrasonic cleaning. If such ultrasonic cleaning is used, as described above, the amount of microparticles released will be extremely small, especially when petroleum pitch activated carbon, which has excellent adsorption ability, is used as the adsorbent. In order to carry out ultrasonic cleaning using the above-mentioned cleaning liquid, it is also possible to supply the cleaning liquid as running water into the ultrasonic cleaning machine and perform the cleaning while causing the water to overflow. However, in order to make effective use of the cleaning liquid, an ultrasonic cleaning tank is placed in the cleaning liquid circulation path, and the particles removed in the ultrasonic cleaning tank are passed through a filtration device along with the cleaning liquid to purify the cleaning liquid. It is preferable to return it to the cleaning tank and use it for circulation. An example of a cleaning device used in such a case is the first cleaning device.
As shown in the figure. In the same figure, the cleaning device includes an ultrasonic cleaning tank 1, a circulation pump 2, and a predetermined number of first, second, and third filter devices 31, 32, and 33, which are three in this case. A cleaning liquid circulation path 4 is formed between them. The ultrasonic cleaning tank 1 has a liquid inlet 41 with mesh and a liquid outlet 42 of the cleaning liquid circulation path 4 in a tank 12 equipped with an ultrasonic vibrator 11, and a stirring propeller 14 driven by a motor 13. It is set up. Further, the tank 12 is filled with the above-mentioned cleaning liquid 5, and the adsorbent 6 is filled therein. In addition, the first to third passing devices 31 to 33 include
Each of the filters is provided with a predetermined pore diameter such that the pore diameter becomes smaller from the first filter to the third filter. By using such a cleaning device and ultrasonically cleaning the adsorbent 6 while circulating the cleaning liquid,
Fine particles on the surface of the adsorbent and within the micropores will be sufficiently removed. Note that the cleaning conditions vary depending on the type of adsorbent, the scale of the equipment, etc., but for example, for 1 kg of petroleum pit activated carbon, the cleaning conditions are generally 1 kg at a flow rate of about 0.5 to 5.0/min.
It is sufficient to wash for about 4 hours. The adsorbent thus ultrasonically cleaned is then preferably decanted several times. This decantation is usually
Thoroughly remove organic colloid using water or physiological saline. In this way, the amount of fine particles existing on the surface and in the micropores of the adsorbent cleaned using the above-mentioned cleaning solution is significantly reduced, and the organic colloidal compounds in the cleaning solution are Afterwards, there is almost no presence on the surface of the adsorbent. Therefore, the adsorption capacity of the adsorbent after washing hardly deteriorates. The adsorbent washed in this way is then
It is filled into a container with water or physiological saline without providing a coating such as a hydrophilic polymer.
In this case, the container may be one for a known adsorption type artificial organ, which has a main body, a blood or plasma inlet and an outlet communicating with the main body, and further prevents the adsorbent filled inside the container from flowing out. To prevent this, a mesh with a predetermined hole diameter is provided near the outlet, preferably near the outlet and the inlet. Next, after such filling, sterilization is performed by autoclave sterilization or γ-ray sterilization,
Artificial organs are manufactured. The artificial organs manufactured in this way are used as DHP columns for artificial kidneys, artificial livers, etc. to adsorb and remove toxic substances or waste substances in blood or plasma in extracorporeal circulation circuits. It is something that can be done. Specific Effects of the Invention According to the present invention, fine particles are sufficiently removed from the adsorbent by the above-mentioned washing, and the artificial organ of the present invention manufactured by filling such an adsorbent can be easily absorbed into a living body. The leakage of microparticles is extremely small, and the development of blood clots and the like is prevented. In this case, the amount of microparticles leaked into the blood is much smaller than in the conventional case of washing with water or physiological saline. Furthermore, even when compared with the case where a coating is provided after washing with water or physiological saline, the amount of leakage is comparable. Furthermore, since there is no need to provide a coating, there is no deterioration in adsorption capacity as in the past, and the artificial organ can be made much smaller than in the past, and the amount of priming can be extremely reduced. In addition, in the cleaning process of the adsorbent, all that is needed is to use the above-mentioned specified cleaning liquid, making the cleaning process extremely simple, and since there is no need to perform a coating process on the adsorbent, manufacturing is extremely easy. It is easy to manufacture and the manufacturing cost is low. Furthermore, unlike when a coating is provided, there is no risk of organic solvent remaining or coating material leaching out. Furthermore, since there is little deterioration of adsorption capacity, the amount of adsorbent used can be reduced, and there is no need for the artificial organ itself to have a complicated special structure, so manufacturing costs can be reduced. Realize. EXAMPLES Hereinafter, the present invention will be explained in more detail by showing examples, comparative examples, and experimental examples of the present invention. Example 1 In the cleaning apparatus shown in Fig. 1, solid state 600 manufactured by Ultrasonic Industry Co., Ltd.
5μ pore cartridge filter,
1μ pore cartridge filter and 0.45μ pore
A cartridge filter was used. This cleaning tank 1
, petroleum pitch activated carbon (manufactured by Kureha Chemical Co., Ltd.)
2 kg of BAC-AZ) was added, and a 0.3% aqueous solution 8 of heparin (average molecular weight approximately 15,000) was added, and the mixture was washed continuously for 3 hours while being circulated by pump 2 at a flow rate of 3/min. The activated carbon from which particulate carbon dust on the surface and inside the micropores had been removed was transferred to a stainless steel container and decanted with physiological saline for 5 minutes.
The heparin was removed almost completely, and the washing solution was replaced with physiological saline. 100 g of the activated carbon thus washed was packed together with physiological saline into a DHP column (direct blood perfusion column) container. This column container is equipped with a mesh having a pore size of 200 μm at the blood outlet and inlet. After this, the column was sealed and sterilized in an autoclave to produce a DHP column. In addition, in the above, the heparin concentration in the washing liquid is expressed as a percentage of g/dl, and the washing liquid concentration below also follows this expression. Example 2 The heparin 0.3% aqueous solution in Example 1 was
Exactly the same as in Example 1 except that the physiological saline solution containing 40% dextran (average molecular weight 18000) was used.
A DHP column was created. Example 3 The heparin 0.3% aqueous solution in Example 1 was
% hydroxyethyl starch (average molecular weight approx.
400000) A DHP column was produced in exactly the same manner as in Example 1, except that the aqueous solution was used. Example 4 The heparin 0.3% aqueous solution in Example 1 was
A DHP column was prepared in exactly the same manner as in Example 1, except that an aqueous solution of modified fluid gelatin (average molecular weight 30,000) was used. Comparative Example 1 A DHP column was prepared in the same manner as in Example 1, except that the heparin aqueous solution in Example 1 was replaced with a physiological saline solution according to the conventional method. Comparative Example 2 After performing ultrasonic cleaning with physiological saline in exactly the same manner as in Comparative Example 1, the activated carbon was dried, and then a poly-hydroxy methacrylate coating was formed on the surface of the activated carbon. That is, 30 g of this coating material was added to ethanol 4 and dissolved by heating, then 2 kg of the above activated carbon was added thereto, the ethanol was evaporated under warm air, and then after the ethanol evaporated, the temperature was heated to 90°C.
The film was left in an oven for 22 days to form a coating.
A DHP column was prepared in exactly the same manner as in Example 1 using 100 g of the activated carbon thus obtained. Experimental Example 1 For each of the seven types of DHP columns prepared in Examples 1 to 4 and Comparative Examples 1 and 2, a dust-free 1% dextran solution that had been passed twice through a 0.22 μ pore membrane filter was added at a flow rate of 200 ml/min. It was washed away. The number of particulate coal dust in the solution flowing out was measured for each 100 ml that initially flowed out. The results are shown in Table 1 below.

[Table] From the results in Table 1, it can be seen that according to the present invention, the amount of microparticles leaked into the dextran solution used as a plasma substitute is significantly reduced compared to the case of using conventional washing with physiological saline. You can see that It can also be seen that the amount of microparticles released was reduced to the same level as when the activated carbon was coated. Experimental Example 2 Produced in Example 1 and Comparative Example 2
In order to confirm the difference in the adsorption capacity of the DHP column,
Clearance was measured using a single pass method using the measuring device shown in the figure. In the figure, storage tank T was filled with three types of physiological saline L containing creatinine, vitamin B ₁₂ and inulin as indicator substances at 10 mg/dl each. On the other hand, the storage tank T is connected to a heat exchanger HE, a pump P, a bubble trap BT, and the above DHP column 7,
As shown in the figure, the blood circuit is connected sequentially through a single-pass blood circuit, and each indicator substance-added saline solution is applied.
The flow rate was 200ml/min. In each case, the clearance was measured using the following formula. Formula C _L = C _Bi −C _Bp /C _Bi × _Q Bwhere, C _L is the clearance (ml/min), C _Bi
and C _Bp are the concentration (mg/dl) of the solute indicator substance at the DHP column inlet and outlet, respectively;
Q _B represents the flow rate (ml/min). In each case, the change in clearance over time was measured. The results are shown in Figure 3. In the figure, a ₁ , a ₂ and a ₃ are for the DHP column in Example 1, and b ₁ , b ₂ and b ₃ are for the DHP column in Comparative Example 2.
These are the changes in the DHP column and these a ₁ to _{a 3}
The subscripts 1 to 3 in b ₁ to _{b 3} represent the results when 1 is creatinine, 2 is vitamin B ₁₂ , and 3 is inulin, respectively. From the results shown in FIG. 3, it can be seen that according to the present invention, the clearance value C _L is extremely high, and no deterioration of the adsorption capacity occurs, compared to the case where the coating is formed after cleaning according to the conventional method. When the changes in clearance were similarly measured for the DHP columns in Examples 2 to 5 and Comparative Example 1, which was washed with physiological saline only, almost the same results as the DHP column of Example 1 in FIG. 3 were obtained. Experimental Example 3 The two types of DHP columns 7 produced in Example 1 and Comparative Example 1 were respectively incorporated into the measuring apparatus shown in FIG. That is, the storage tank T is filled with a 1% aqueous solution L' of dust-free dextran, and this is passed through a 1μ pore filter F, pump P and
It was connected to DHP column 7 to form a circulation path. Perfusion was carried out for 2 hours at a flow rate of 200 ml/min. While performing such perfusion, 50 ml of the liquid that initially flowed out after the start of circulation was collected, and the number of fine particles of 1.5 μ or more in the test liquid was counted. Such measurements were repeated for 50 ml of test solution at 10 minute intervals. In this case, the number of particles t minutes after the start is St (particles/
ml), and the number of particles after (t+10) minutes is St+10(particles/
ml), the number of particles flowing out in these 10 minutes can be calculated as (St + St + 10) x 200 x 10 ÷ 2.
Therefore, such measurements and calculations were performed over a period of 2 hours, and the total number of particles flowing out during the 2 hours of perfusion was calculated. As a result, the total number of particles flowing out of the DHP column of Comparative Example 1 was 18 times that of Example 1. It was found that the amount of microparticles released was reduced by 95%. It should be noted that such effects were achieved to the same extent in Examples 2 to 5 as well. Experimental Example 4 The DHP column obtained in Example 1 was applied to a patient who had fallen into a hepatic coma due to severe hepatitis after confirming that it completely passed the sterility test and pyrogen test. The results before and after perfusion are shown in Table 2 below. After perfusion, the patient showed obvious relief of symptoms, such as awakening from hepatic coma, and
No serious side effects were observed due to the use of DHP columns.

【table】 [Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one example of a cleaning device used in the present invention, FIG. 2 is an explanatory diagram showing a measuring device used in Experimental Example 2 for confirming the effects of the present invention, and FIG. is the change over time in the clearance of the artificial organ obtained by the present invention when measured using the measuring device shown in FIG.
FIG. 4 is a diagram showing a comparison with that of an artificial organ obtained by a conventional method, and FIG. 4 is an explanatory diagram showing a measuring device used in Experimental Example 3 for confirming the effects of the present invention. 1... Ultrasonic cleaning tank, 5... Organic colloid aqueous solution, 6... Adsorbent, 7... DHP column.

Claims (1)

[Scope of Claims] 1. A method for producing an artificial organ in which a container is filled with a washed adsorbent, which uses a polysaccharoid having an average molecular weight of 4,000 or more and having a surfactant effect and a protective colloid effect and being harmless to living organisms. The adsorbent is washed by applying ultrasonic waves in an aqueous solution of a polypeptide-based compound or a polypeptide-based compound, then washed with water or physiological saline, and then filled into a container without drying. Characteristic method for manufacturing artificial organs. 2. The method for manufacturing an artificial organ according to claim 1, wherein the adsorbent is petroleum pitch activated carbon.