JP5985027B2 - Method for producing pharmaceutical adsorbent for oral administration - Google Patents

Description

The present invention relates to a method for producing a pharmaceutical adsorbent for oral administration comprising activated carbon made from regenerated cellulose, and particularly for oral administration comprising activated carbon derived from cellulose excellent in selective adsorption performance and adsorption performance of toxic substances. The present invention relates to a method for producing a pharmaceutical adsorbent.

  Patients with renal or liver disease accumulate toxic substances in the blood, resulting in encephalopathy such as uremia and impaired consciousness. The number of these patients tends to increase year by year. For the treatment of patients, hemodialysis type artificial kidneys and the like that remove toxic substances from the body are used. However, such an artificial kidney requires a special engineer for handling from the viewpoint of safety management, and it is regarded as a problem that it requires physical, mental and economic burden on the patient when blood is taken out of the body. It is not always satisfactory.

  As an alternative to artificial organs, adsorbents for oral administration that are taken orally, adsorb toxic substances in the body, and excrete outside the body have been developed (see Patent Document 1, Patent Document 2, etc.). However, since these adsorbents are adsorbents that utilize the adsorption performance of activated carbon, it cannot be said that the adsorption capacity of the toxin to be removed and the selective adsorption of toxins to useful substances are not sufficient. In general, activated carbon has high hydrophobicity and includes a problem that it is not suitable for adsorption of ionic organic compounds such as arginine and creatinine represented by causative substances and precursors of uremia.

  Therefore, in order to improve the problems of the activated carbon adsorbent, anti-nephrosis consisting of activated carbon using raw materials such as wood, petroleum or coal-based pitches to form spherical resin compounds. Syndrome agents have been reported (see, for example, Patent Document 3). The above-mentioned activated carbon is obtained by using petroleum-based hydrocarbon (pitch) or the like as a raw material, adjusting the particle size to be relatively uniform, carbonizing and activating. In addition, an adsorbent for oral administration has been reported in which the particle size of the activated carbon itself is made relatively uniform, and the distribution of pore volume and the like in the activated carbon is adjusted (see Patent Document 4). Thus, medicinal activated carbon improves the poor fluidity in the intestine with a relatively uniform particle size, and at the same time, improves the adsorption performance of the activated carbon by adjusting the pores. planned. Therefore, it is taken by many patients with mild chronic renal failure.

  Medicinal activated carbon is required to rapidly and efficiently adsorb causative substances and precursors of uremia. However, with existing medicinal activated carbon, it is difficult to reduce the particle size while maintaining the spherical shape. Moreover, it cannot be said that the adjustment of the pores in the conventional medicinal activated carbon is good, and the adsorption performance is not always sufficient, so the daily dose must be increased. In particular, since chronic renal failure patients have limited water intake, swallowing with a small amount of water has been very painful for the patient.

  In addition, in the digestive tract such as the stomach and the small intestine, it is an environment in which various substances such as sugars, proteins and other compounds essential for physiological functions and enzymes secreted from the intestinal wall are mixed. Therefore, a medicinal activated carbon with selective adsorption performance that adsorbs arginine, creatinine, etc., which are causative substances of uremia, while suppressing adsorption of compounds such as trypsin, which is essential for physiological functions, is desired. It was rare.

  Further, the aforementioned adsorbent for oral administration uses a thermosetting resin such as petroleum pitch or phenol resin as a starting material. Since it depends on petrochemical-derived raw materials, it is not preferable from the viewpoint of carbon neutrality. Furthermore, since the production energy cost of the raw material becomes extremely high, medicinal activated carbon that is an adsorbent for oral administration derived from biomass has been demanded.

Japanese Patent No. 3835698 JP 2008-303193 A Japanese Patent Laid-Open No. 6-135841 JP 2002-308785 A

  The present invention has been made in view of the above points, and is a pharmaceutical adsorbent for oral administration that is excellent in the adsorption capacity and selective adsorption of a toxin to be removed while being in a small dose, and is economical and suppresses environmental burden. A manufacturing method is provided.

That is, the invention according to claim 1 has an average pore diameter of 1.5 to 2.2 nm, a BET specific surface area of 700 to 3000 m ² / g, an average particle diameter of 100 to 1100 μm, and a surface oxide amount of 0.05 meq / In the production of spherical activated carbon having a g density of 0.4 or more and a packing density of 0.4 to 0.8 g / mL, a viscose solution is introduced into an acidic coagulation bath to promote regeneration into cellulose through coagulation of the viscose solution. A spherical regenerated cellulose is obtained in the coagulation bath, the spherical regenerated cellulose is carbonized at 300 to 700 ° C. in a nitrogen atmosphere, steam activated at 750 to 1000 ° C., acid washed, and 500 to 800 ° C. The present invention relates to a method for producing a pharmaceutical adsorbent for oral administration, characterized by heat treatment.

The invention of claim 2 has an average pore diameter of 1.5 to 2.2 nm, a BET specific surface area of 700 to 3000 m ² / g, an average particle diameter of 100 to 1100 μm, a surface oxide amount of 0.05 meq / g or more, In the production of spherical activated carbon having a packing density of 0.4 to 0.8 g / mL, the coagulation bath is introduced by introducing a viscose solution into an acidic coagulation bath to promote regeneration to cellulose through coagulation of the viscose solution. A spherical regenerated cellulose is obtained, impregnated with spherical purified cellulose or spherical regenerated cellulose in ammonium phosphate or metal phosphate, and then carbonized at 300 to 700 ° C. in a nitrogen atmosphere at 750 to 1000 ° C. The present invention relates to a method for producing a pharmaceutical adsorbent for oral administration, which comprises steam activation, acid cleaning and heat treatment at 500 to 800 ° C.

The invention according to claim 3 is the production of the adsorbent for oral administration according to claim 1 or 2, wherein the spherical activated carbon is a therapeutic or preventive agent for renal disease for oral administration or liver disease for oral administration . Related to the method.

According to the method for producing a medicinal adsorbent for oral administration according to the invention of claim 1, the average pore diameter is 1.5 to 2.2 nm, the BET specific surface area is 700 to 3000 m ² / g, and the average particle size is 100 to In producing spherical activated carbon having 1100 μm, a surface oxide amount of 0.05 meq / g or more, and a packing density of 0.4 to 0.8 g / mL, a viscose solution is introduced into an acidic coagulation bath and the viscose is added. Regeneration into cellulose is promoted through coagulation of the solution to obtain spherical regenerated cellulose in the coagulation bath. The spherical regenerated cellulose is carbonized at 300 to 700 ° C. in a nitrogen atmosphere, and steam activation is performed at 750 to 1000 ° C. Because it is acid-washed and heat-treated at 500-800 ° C., it is excellent in adsorption capacity and selective adsorption of toxins to be removed while being in a small dose, and is for oral administration with economical and low environmental impact It becomes medical adsorbent was able to establish a method for producing a medical adsorbent using raw materials derived from biomass.

According to the method for producing a pharmaceutical adsorbent for oral administration according to the invention of claim 2, the average pore diameter is 1.5 to 2.2 nm, the BET specific surface area is 700 to 3000 m ² / g, and the average particle size is 100 to In producing spherical activated carbon having 1100 μm, a surface oxide amount of 0.05 meq / g or more, and a packing density of 0.4 to 0.8 g / mL, a viscose solution is introduced into an acidic coagulation bath and the viscose is added. Regeneration into cellulose is promoted through coagulation of the solution to obtain spherical regenerated cellulose in the coagulation bath. After impregnating spherical purified cellulose or spherical regenerated cellulose with ammonium phosphate or metal phosphate, under a nitrogen atmosphere Carbonized at 300-700 ° C, steam activated at 750-1000 ° C, acid washed and heat-treated at 500-800 ° C, so should be removed even with a small dose Excellent adsorption capacity and selective adsorption of oxygen, it becomes economical and medical adsorbent for oral administration with less environmental impact, which together with the use of raw materials derived from biomass, and facilitate control of the physical properties of the be ready spherical activated carbon pharmaceutical The production method of the adsorbents for the use was established.

According to the method for producing an adsorbent for oral administration according to the invention of claim 3, in the invention of claim 1 or 2, the spherical activated carbon is a therapeutic agent for renal disease for oral administration or liver disease for oral administration. Alternatively, since it is a prophylactic agent, it has a high effect of selectively adsorbing a causative substance of kidney disease or liver disease, and can provide a pharmaceutical adsorbent for oral administration that is promising as a therapeutic agent or prophylactic agent.

Medical adsorbent of the invention, the starting material is a regenerated cellulose, carbonizing the cellulose material, a spherical shaped activated carbon have developed pores by activation. The raw material regenerated cellulose is high-purity cellulose prepared from pulp by a conventionally known viscose method or copper ammonia method.

  Or it is the cellulose prepared after melt | dissolving a pulp using ionic liquids, such as NMMO (N-methylmorpholine oxide) and BMMCL (1-butyl-3-methylimidazolium chloride). In order to adjust the viscosity of the cellulose solution and the pore distribution of the cellulose coagulum, 20% by weight or less of a soluble or water-insoluble starch can be added to the cellulose used as a raw material. Furthermore, in order to further increase the strength of the activated activated carbon, 20% by weight or less of inorganic fiber such as cellulose fiber or silica can be added as a filler.

The shape of the regenerated cellulose is preferably granular in view of taking it as a pharmaceutical adsorbent. In particular, considering the fluidity in the intestinal tract, the preferred shape of the medicinal activated carbon is spherical. Regenerated cellulose and the like can be obtained by coagulation under water or strong acid. A viscose solution having a predetermined concentration is dropped into water or a strong acid coagulation liquid, or is stirred and dispersed in the coagulation liquid by a known method to easily form spherical cellulose particles. The average particle size of the spherical cellulose particles is arbitrarily adjusted depending on the concentration and viscosity of the viscose solution, the diameter of the liquid discharge nozzle during coagulation, the rotation speed of the coagulation liquid, and the like. The cellulose solution discharge device is adjusted so that activated carbon having an average particle diameter of 100 to 1100 μm is finally obtained. The stage prior to carbonization of the dried spherical form cellulose is the particle size of 150～2000Myuemu.

  Cellulose particles are generally considered to be used for cosmetic powders and pharmaceutical excipients. Since the cellulose particles are required to have flexibility and self-disintegrating property, the hardness is not particularly expected. The microcrystalline cellulose fine particles are used as a molding accelerator such as spheroidization of pharmaceuticals, and are formulated together with a drug to become the core of the drug. However, in the case of microcrystalline cellulose, even if spherical cellulose particles having a certain particle diameter and hardness can be prepared, it is not expected to maintain hardness in the body.

On the other hand, cellulose is an ingredient derived from natural products, and has an advantage that the load of raw material procurement and raw material preparation is small. Moreover, the time required for activation is short compared with the activated carbon of a phenol-type resin. Therefore, the inventors adjust the particle size and hardness by controlling the concentration when dissolving cellulose, adjusting the degree of molecular polymerization of viscose, or blending and impregnating incombustible components to increase hardness. Clarified that it can be adjusted over a wide range. By carbonization and activation the ball-like product of cellulose obtained thereon, has led to the conventional art to obtain a medical adsorbent spherical activated carbon having a desired hardness while the cellulose starting material is difficult .

  The spherical activated carbon which is the main component of the pharmaceutical adsorbent will be described from its production method. The spherical cellulose made of the regenerated cellulose is accommodated in a firing furnace such as a cylindrical retort electric furnace, and is carbonized at 300 to 700 ° C. in a nitrogen atmosphere to become spherical carbonized cellulose.

Alternatively, spherical shape cellulose consisting of the regenerated cellulose is impregnated in a solution of ammonium phosphate or phosphoric acid metal salts such as sodium phosphate and potassium phosphate. The spherical cellulose containing phosphate is accommodated in a firing furnace such as a cylindrical retort electric furnace, and is carbonized at 300 to 700 ° C. in a nitrogen atmosphere to form spherical carbonized cellulose. The impregnation into the phosphate solution is performed for the purpose of making the spherical cellulose flame retardant.

  The spherical carbonized cellulose obtained by any of the aforementioned processes is steam activated at 750 to 1000 ° C., preferably 800 to 1000 ° C., more preferably 850 to 950 ° C. The activation time is 0.5 to 50 hours, although it depends on the production scale and equipment. After cooling in a nitrogen atmosphere, the activated spherical carbonized cellulose is acid washed with dilute hydrochloric acid or the like. After acid cleaning, it is washed with water to remove impurities such as ash. After the acid washing, the activated spherical carbonized cellulose is heat-treated in a mixed gas containing oxygen and nitrogen for 15 minutes to 2 hours to remove residual hydrochloric acid. And the surface oxide amount of activated carbon is adjusted by passing through each process. During the heat treatment, the oxygen concentration is controlled to 0.1 to 5 vol% or less. After acid cleaning, the activated spherical carbonized cellulose is heated at 500 to 800 ° C.

  In any production method, the spherical activated carbon that has undergone final heating is sieved by a sieve or the like, and the particle diameter of the spherical activated carbon is adjusted and sorted. In this way, the spherical activated carbon which is the pharmaceutical adsorbent of the present invention is obtained. By sieving, activated carbon having a large particle size that has a low adsorption rate and cannot sufficiently exert the adsorption force is removed.

  The spherical activated carbon obtained from the above-described production method adsorbs the causative substances of liver dysfunction and renal dysfunction described in the examples described later, and suppresses adsorption of enzymes necessary for the living body as much as possible. It is required to improve the adsorption performance and to exhibit sufficient adsorption performance with a relatively small dose. In order to find the harmonious range of the properties to be provided, the pharmaceutical adsorbent is: [1] average pore diameter, [2] BET specific surface area, [3] average particle size, [4] surface oxide amount, [5] packing It is defined by the density index. Then, as is clear from the tendency and the like of examples described later, suitable range values for each index are derived. In addition, the measurement methods, various conditions, etc. of the said activated carbon described below are explained in full detail in an Example.

  First, [1] The average pore diameter is defined as 1.5 to 2.2 nm. When the average pore diameter is less than 1.5 nm, the adsorption performance of the toxic substance is lowered, which is not preferable. Conversely, when the average pore diameter exceeds 2.2 nm, it is not preferable because there are many pores that adsorb polymers such as enzymes and polysaccharides necessary for living bodies. For this reason, the average pore diameter is preferably within the above range, and more preferably 1.6 to 2.0 nm.

[2] The BET specific surface area is defined as 700 to 3000 m ² / g. When the BET specific surface area is less than 700 m ² / g, the adsorption performance of the toxic substance is lowered, which is not preferable. If the BET specific surface area exceeds 3000 m ² / g, the strength of the spherical activated carbon itself is likely to deteriorate since the pore volume in addition to the packing density is deteriorated becomes larger. Accordingly, the BET specific surface area is preferably in the above range, and is preferably 900 to 2400 m ² / g, more preferably 1000 to 2000 m ² / g.

  [3] The average particle size is defined as 100 to 1100 μm. When the average particle size is less than 100 μm, adsorption of useful substances such as digestive enzymes tends to occur, which is not preferable from the viewpoint of selective adsorption. In addition, an average particle size of less than 100 μm, for example, 20 μm, can be theoretically assumed, but is actually difficult to manufacture. When the average particle size exceeds 1100 μm, the particles become too large and the surface area is relatively reduced, so that the adsorption rate is lowered. Thus, the average particle size is preferably within the above range, preferably 100 to 1000 μm, more preferably 300 to 1000 μm. The “average particle size” in the present specification means the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method using the laser light scattering type particle size distribution measuring apparatus of the examples described later. To do.

  [4] The amount of surface oxide is specified to be 0.05 meq / g or more. The increase in the amount of surface oxides on the surface of the spherical activated carbon is to increase ionic functional groups on the surface of the activated carbon. For this reason, in order to improve the adsorption | suction performance of an ionic organic compound, it is thought that the amount of surface oxides is 0.05 meq / g or more, Furthermore, 0.10 meq / g or more is desirable. In addition, when the amount of surface oxides is less than 0.05 meq / g, it cannot be said that the adsorption characteristics are inferior.

  [5] The packing density is specified to be 0.4 to 0.8 g / mL. When the filling density is less than 0.4 g / mL, the dose increases and it becomes difficult to swallow during oral administration. When the packing density exceeds 0.8 g / mL, the desired selective adsorptivity balance is lacking, which is inappropriate. For these reasons, the packing density is preferably in the above range, and preferably 0.5 to 0.7 g / mL.

  Spherical activated carbon having the above-mentioned physical properties is a drug intended for oral administration, and serves as a therapeutic or preventive agent for kidney disease or liver disease. As described above, a causative substance of a disease or chronic symptom is adsorbed and retained in the pores developed on the surface of the spherical activated carbon, and discharged outside the body, thereby preventing the deterioration of the symptom and leading to improvement of the disease state. In addition, when there is a congenital or acquired metabolic abnormality or there is a risk of it, the internal concentration of the causative substance of the disease or chronic symptoms can be lowered by taking spherical activated carbon in advance. Therefore, it may be taken as a preventive measure to prevent worsening of symptoms.

  Examples of renal diseases include chronic renal failure, acute renal failure, chronic pyelonephritis, acute pyelonephritis, chronic nephritis, acute nephritic syndrome, acute progressive nephritic syndrome, chronic nephritic syndrome, nephrotic syndrome, nephrosclerosis, interstitial nephritis Tubulopathies, lipoid nephrosis, diabetic nephropathy, renovascular hypertension, hypertension syndrome, or secondary renal diseases associated with the above-mentioned primary diseases, and mild renal failure before dialysis. Examples of liver diseases include fulminant hepatitis, chronic hepatitis, viral hepatitis, alcoholic hepatitis, liver fibrosis, liver cirrhosis, liver cancer, autoimmune hepatitis, drug allergic liver disorder, primary biliary cirrhosis, tremor ), Encephalopathy, metabolic abnormalities, functional abnormalities.

  The dose when spherical activated carbon is used as an adsorbent for oral medicine cannot be uniformly defined because it is affected by age, sex, physique or medical condition. However, in general, in the case of human subjects, 1 to 20 g per day and 2 to 4 doses per day are assumed in terms of the weight of spherical activated carbon. Spherical activated carbon adsorbents for oral medicine are administered in the form and dosage form of powders, granules, tablets, dragees, capsules, suspensions, sticks, sachets or emulsions.

[Measurement items and measurement method]
The inventors relate to the spherical activated carbons of Examples and Comparative Examples described later, the average particle diameter (μm), the BET specific surface area (m ² / g), the pore volume (mL / g), the average pore diameter (nm). ), Packing density (g / mL), and surface oxide amount (meq / g) were measured. At the same time, the adsorption performance of creatinine and arginine as toxic substances (toxic substances) was evaluated, and the adsorption performance of trypsin as a useful substance was evaluated. In addition, iodine adsorption power (mg / g) was also measured in order to evaluate general adsorption performance of activated carbon.

  The average particle diameter (μm) is measured using a laser light scattering particle size distribution measuring device (SALD3000S) manufactured by Shimadzu Corporation, and the particle diameter at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method. It was.

The BET specific surface area (m ² / g) was determined by measuring the nitrogen adsorption isotherm at 77K with BELSORP mini manufactured by Nippon Bell Co., Ltd., and using the BET method.

The pore volume (mL / g) was determined by the following two methods.
The N ₂ pore volume V _mi was determined from the amount of nitrogen adsorbed in terms of liquid nitrogen at a relative pressure of 0.990 using BELSORPmini manufactured by Nippon Bell Co., Ltd., applying Gurvitsch's law. This method was intended for a pore diameter range of 0.6 to 100 nm.
Mercury pore volume V _me was set at a contact angle of 130 °, a surface tension of 484 dynes / cm (484 mN / m) using an autopore 9500 manufactured by Shimadzu Corporation, and mercury with a pore diameter of 7.5 to 15000 nm. The pore volume was determined by the press-fitting method.

The average pore diameter Dp (nm) was determined by the following equation (i) assuming that the pore shape was cylindrical. In the formula, V _mi is the N ₂ pore volume described above, and Sa is the BET specific surface area.

  The packing density (g / mL) was measured according to JIS K 1474 (2007).

Surface oxide content (meq / g) is when applying the method of Boehm, filtered after shaking the spherical activated carbon in an aqueous solution 0.05N sodium hydroxide and titration of the filtrate with 0.05N hydrochloric Of sodium hydroxide.

  Iodine adsorption power (mg / g) was measured in accordance with JIS K 1474 (2007).

Using creatinine and arginine as toxic substances and trypsin as a useful substance as examples of adsorbed substances, the adsorption performance by each spherical activated carbon was evaluated. First, each adsorbed substance was dissolved in a phosphate buffer having a pH of 7.4 to prepare a standard solution having a concentration of the adsorbed substance of 0.1 g / L.
2.5 g of the spherical activated carbons of Examples and Comparative Examples were added to 50 mL of a standard solution of creatinine, and the mixture was shaken at 37 ° C. for 3 hours.
0.5 g of the spherical activated carbons of Examples and Comparative Examples was added to 50 mL of a standard solution of arginine, and the mixture was shaken at 37 ° C. for 3 hours.
0.125 g of the spherical activated carbons of Examples and Comparative Examples was added to 50 mL of a trypsin standard solution, and the mixture was shaken for 3 hours at a temperature of 21 ° C.

  Thereafter, the filtrate obtained by filtration was measured for the TOC concentration (mg / L) in each filtrate using a total organic carbon meter (manufactured by Shimadzu Corporation, TOC5000A), and the mass of the adsorbed substance in each filtrate. Was calculated. The adsorption rate (%) of each substance to be adsorbed was obtained from equation (ii).

[Production of spherical activated carbon of Examples and Comparative Examples]
<Example 1>
2 kg of dissolved pulp LNDP (manufactured by Nippon Paper Chemical Co., Ltd.) with 90% by weight α-cellulose per unit weight and sodium hydroxide solution (concentration 18.5%) are immersed for 15 minutes at 55 ° C. The sodium hydroxide content was removed to prepare alkali cellulose (AC) having a cellulose concentration of 33.5% by weight. Alkaline cellulose is aged at 40 ° C. for 7 hours, 5 kg of the alkali cellulose and 436 mL of carbon disulfide having a purity of 97% or more are reacted for 70 minutes, and cellulose xanthate having a viscosity of 0.055 Pa · s (55 cP) at 40 ° C. Got.

  After completion of the reaction, about 13 L of dilute sodium hydroxide solution was added to cellulose xanthate and stirred for 100 minutes to obtain viscose. Further, viscose having a cellulose concentration of 9.0% was prepared through steps of defoaming, aging and filtration. The prepared viscose is diluted with distilled water to a viscose concentration of 80%, and from a nozzle having an inner diameter of about 0.9 mm (18 gauge) to a gently stirred 40 ° C. large excess dilute sulfuric acid bath (coagulation bath). The cellulose was regenerated by dripping to obtain a spherical product of cellulose (so-called regenerated cellulose). At this time, the spherical cellulose was immersed in a dilute sulfuric acid bath for 30 minutes. The spherical cellulose was washed with a large excess of water to remove dilute sulfuric acid, and then immersed in a dilute aqueous sodium hydroxide solution at 40 ° C. for 1 hour or longer. After washing again with a large excess of water to remove the sodium hydroxide content in the spherical product, it was dried at 105 ° C. to obtain spherical cellulose.

  To 250 g of the spherical cellulose obtained by the above preparation, 500 mL of an aqueous ammonium phosphate solution (concentration 5%) was added and allowed to stand for 12 hours. Thereafter, the moisture was removed, and drying was performed at 120 ° C. for 3 hours by a dryer. The whole amount of the spherical cellulose that had undergone the ammonium phosphate treatment was placed in a cylindrical retort electric furnace and sealed with nitrogen, then heated to 600 ° C. at 100 ° C./hour, and kept at that temperature for 1 hour for carbonization. Thereafter, the carbide was heated to 900 ° C., steam was added, and the temperature was maintained for 1 hour for activation (activation temperature 900 ° C., activation time 1 hour). The activated activated carbon was washed with dilute hydrochloric acid, filled with nitrogen, and heat-treated at 600 ° C. for 1 hour in a cylindrical retort electric furnace to obtain the spherical activated carbon of Example 1 (yield 19.6%). there were).

<Example 2>
Spherical activated carbon of Example 2 was obtained according to Example 1 except that the activation temperature in Example 1 was 750 ° C. and the activation time was 2 hours (yield was 30.1%).

<Example 3>
Spherical activated carbon of Example 3 was obtained according to Example 1 except that the activation temperature in Example 1 was 750 ° C. and the activation time was 8 hours (yield was 22.6%).

<Example 4>
In preparing spherical cellulose in Example 4, viscose having a cellulose concentration of 9.0% was diluted with distilled water to a viscose concentration of 50%, and gently stirred from a nozzle having an inner diameter of about 0.9 mm (18 gauge). The cellulose was regenerated by dripping into a large excess of dilute sulfuric acid bath (coagulation bath) at 40 ° C. to obtain a spherical product of cellulose (regenerated cellulose).

  To 250 g of the spherical cellulose obtained by the above preparation, 500 mL of an aqueous ammonium phosphate solution (concentration 5%) was added and allowed to stand for 12 hours. Thereafter, the moisture was removed, and drying was performed at 120 ° C. for 3 hours by a dryer. The whole amount of the spherical cellulose that had undergone the ammonium phosphate treatment was placed in a cylindrical retort electric furnace and sealed with nitrogen, then heated to 600 ° C. at 100 ° C./hour, and kept at that temperature for 1 hour for carbonization. Thereafter, the carbide was heated to 900 ° C., steam was added and the temperature was maintained for 45 minutes for activation (activation temperature 900 ° C., activation time 0.75 hour). The activated activated carbon was washed with dilute hydrochloric acid, filled with nitrogen, and heat-treated at 600 ° C. for 1 hour in a cylindrical retort electric furnace to obtain spherical activated carbon of Example 4 (yield was 14.4%). there were).

<Example 5>
In preparing spherical cellulose in Example 5, viscose having a cellulose concentration of 9.0% was diluted with distilled water to a viscose concentration of 50%, and gently stirred from a nozzle having an inner diameter of about 0.7 mm (19 gauge). The cellulose was regenerated by dripping into a large excess of dilute sulfuric acid bath (coagulation bath) at 40 ° C. to obtain a spherical product of cellulose (regenerated cellulose).

  Subsequent ammonium phosphate treatment, heating, steam activation, dilute hydrochloric acid washing, and heating treatment all obtained spherical activated carbon of Example 5 according to Example 4 (yield was 15.1%).

<Example 6>
In Example 6, spherical cellulose (Daito Kasei Kogyo Co., Ltd., CELLULOSEBEADS D-200) was used. To 250 g of this spherical cellulose, 500 mL of an aqueous ammonium phosphate solution (concentration 5%) was added and allowed to stand for 12 hours. Thereafter, the moisture was removed, and drying was performed at 120 ° C. for 3 hours by a dryer. The whole amount of the spherical cellulose that had undergone the ammonium phosphate treatment was placed in a cylindrical retort electric furnace and sealed with nitrogen, then heated to 600 ° C. at 100 ° C./hour, and kept at that temperature for 1 hour for carbonization. Thereafter, the carbide was heated to 900 ° C., steam was added, and the temperature was maintained for 30 minutes for activation (activation temperature 900 ° C., activation time 0.5 hour). The activated activated carbon was washed with dilute hydrochloric acid, filled with nitrogen, and heat-treated at 750 ° C. for 15 minutes in a cylindrical retort electric furnace to obtain spherical activated carbon of Example 6 (yield was 27.1%). there were).

<Comparative example 1>
250 g of the spherical cellulose prepared in Example 1 was placed in a cylindrical retort electric furnace, filled with nitrogen, heated to 600 ° C. at a rate of 100 ° C./hour, and kept at 600 ° C. for 1 hour for carbonization. Thereafter, the carbide was heated to 900 ° C., steam was added, and the activation was maintained at 900 ° C. for 1 hour (activation temperature 900 ° C., activation time 1 hour). The activated activated carbon was washed with dilute hydrochloric acid, filled with nitrogen, and heat treated at 600 ° C. for 1 hour in a cylindrical retort electric furnace to obtain the spherical activated carbon of Comparative Example 1 (the yield was 11.6%). )

<Comparative example 2>
After adding 250 g of spherical phenol resin (AH-1131 manufactured by Lignite Co., Ltd.) to the reaction kettle, filling nitrogen and adjusting the oxygen concentration to 3% or less, the temperature was raised to 600 ° C. at 100 ° C./hour. Carbonization was carried out by maintaining at temperature for 1 hour. The carbide was heated to 900 ° C., steam was added, and the temperature was maintained for 1 hour to activate. The activated activated carbon was washed with dilute hydrochloric acid, filled with nitrogen, and heat-treated at 600 ° C. for 1 hour in a cylindrical retort electric furnace to obtain a spherical activated carbon of Comparative Example 2 (yield was 45.6%). there were).

<Comparative Example 3>
Spherical activated carbon of Comparative Example 3 was obtained according to Comparative Example 2 except that the activation time in Comparative Example 2 was 3 hours (yield was 29.3%).

With respect to the spherical activated carbon of each example and comparative example, the physical property values are shown in Tables 1 to 3 together with the reaction conditions of the spherical activated carbon. In order from the top of the table, carbonization conditions (° C. × hr), activation conditions (° C. × hr), temperature rise conditions (° C./hr), yield (%), average pore diameter (nm), BET specific surface area (m ² / g), average particle size (μm), packing density (g / mL), mercury pore volume and N ₂ pore volume (both mL / g), surface oxide amount (meq / g), iodine adsorption capacity ( mg / g), creatinine, arginine and trypsin adsorption rate (%). In the table, “<0.1” indicates the measurement limit value or less.

[Results and discussion]
The spherical activated carbon of each Example showed substantially the same physical property values as compared with the spherical activated carbon derived from the existing spherical phenol resin (Comparative Example 2). Thus, it was proved that spherical cellulose is useful as a raw material that can substitute for the spherical phenol resin. In addition, the spherical activated carbon of each example exhibited selective adsorptivity while suppressing the adsorption of useful substances such as trypsin while increasing the adsorption rate of toxic substances such as creatinine and arginine. In particular, Examples 1 to 3 hardly adsorb trypsin, and Examples 4 to 6 greatly suppress trypsin adsorption. From the results of adsorption measurement, the spherical activated carbon of each Example is extremely excellent in selective adsorption performance.

  Furthermore, the packing density of the spherical activated carbon in the examples suggests the possibility of a pharmaceutical adsorbent in a very compact dosage form depending on the embodiment. Therefore, it can be said that it is desirable as a pharmaceutical adsorbent that efficiently absorbs toxic substances.

  The spherical activated carbon produced by the production method of the present invention reaches the digestive tract by oral administration, and is extremely promising for use as a pharmaceutical adsorbent that efficiently absorbs and excretes toxic substances while suppressing absorption of substances necessary for the living body. It is.

Claims (3)

The average pore diameter is 1.5 to 2.2 nm, the BET specific surface area is 700 to 3000 m ² / g, the average particle size is 100 to 1100 μm, the surface oxide amount is 0.05 meq / g or more, and the packing density is 0.4. In the production of spherical activated carbon to be ~ 0.8 g / mL,
Introducing a viscose solution into an acidic coagulation bath to promote regeneration into cellulose through coagulation of the viscose solution to obtain spherical regenerated cellulose in the coagulation bath,
Regenerated cellulose of the spherical carbonized under 300 to 700 ° C. nitrogen atmosphere, subjected to steam activation at 750 to 1000 ° C., acid washed and 500 to 800, characterized in that a heat treatment at ° C. for oral administration medical adsorbent Manufacturing method. The average pore diameter is 1.5 to 2.2 nm, the BET specific surface area is 700 to 3000 m ² / g, the average particle size is 100 to 1100 μm, the surface oxide amount is 0.05 meq / g or more, and the packing density is 0.4. In the production of spherical activated carbon to be ~ 0.8 g / mL,
Introducing a viscose solution into an acidic coagulation bath to promote regeneration into cellulose through coagulation of the viscose solution to obtain spherical regenerated cellulose in the coagulation bath,
After impregnating spherical purified cellulose or spherical regenerated cellulose with ammonium phosphate or metal phosphate, carbonization is performed at 300 to 700 ° C. in a nitrogen atmosphere, steam activation is performed at 750 to 1000 ° C., and acid cleaning is performed to 500 to 500 A method for producing a pharmaceutical adsorbent for oral administration, comprising heat-treating at 800 ° C. 3. The method for producing a pharmaceutical adsorbent for oral administration according to claim 1 or 2, wherein the spherical activated carbon is a therapeutic agent or a preventive agent for renal disease for oral administration or liver disease for oral administration.