JPS6339601B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to antitumor agents. An object of the present invention is to provide an antitumor agent that can be easily mass-produced and has almost no toxicity. Strains of microorganisms belonging to the genus Alcaligenes or Agrobacterium produce water-insoluble, thermo-gelaable glucans (hereinafter TAK-
The production of Japanese Patent Application Publication Nos. 43-7000, 48-32673, 48-32674
and British Patent No. 1352938. However, its medicinal uses are still completely unknown. The present inventors have developed TAK-N and a partially hydrolyzed low polymer thereof (hereinafter abbreviated as TAK-D).
As a result of conducting various studies on the carboxymethylated derivatives of CMTAK (hereinafter abbreviated as CMTAK), we discovered that they have strong antitumor effects and that their tumor inhibition rate and tumor eradication effect are extremely high. By continuing this process, we finally completed the present invention. Water-insoluble, heat-solidifying β used in the present invention
-1,3-glucan (TAK-N) is derived from Agrobacterium radiobacter (IFO13127,
ATCC6466), Agrobacterium radiobacter U-19 (IFO13126, ATCC21679, Microtechnical Research Institute No. 1166), Alcaligenes fuecalis
Bal myxogenes NTK-u (IFO13140,
It is produced by culturing Alcaligenes fuecalis bal myxogenes K.
-1,3-glucan is the main bonding mode, is insoluble in water, and many of them gel and solidify when heated with water, a property not found in other β-1,3-glucans. have. The degree of polymerization of TAK-N can vary depending on the manufacturing method. For example, the method of Manners et al. (Carbohydrate Research, Vol. 17, p. 109, 1971)
The average degree of polymerization is approximately 70-
It usually indicates 1000, but it is often 300-500. and,
These are generally coagulable by heating, but lose coagulability when the average degree of polymerization decreases. For example, average degree of polymerization
It is non-coagulable at 113, but coagulable at about 170. The present inventors found that CMTAK has strong antitumor effects. TAK-D is produced by hydrolysis of TAK-N. Hydrolysis means include conventionally well-known acid hydrolysis, alkaline hydrolysis, and enzymatic hydrolysis using β-1,3-glucanase. To separate TAK-D from the reaction mixture, various methods used for purification and fractionation of polysaccharides and oligosaccharides, such as precipitation in acidic conditions, precipitation by addition of ethanol, gel filtration, etc., can be used. In this manner, various low polymers having a desired average degree of polymerization can be separated. TAK-D as used in the present invention includes all kinds of low polymers produced by partial hydrolysis of TAK-N. obtained from a culture of microorganisms, as described above.
The average degree of polymerization of TAK-N covers a wide range. Since β-1,3-glucan produced in the culture tends to be hydrolyzed as the culture time increases, it is also possible to produce TAK-N with a degree of polymerization even lower than the above range. On the other hand, since TAK-D is produced by hydrolysis of TAK-N, its average degree of polymerization is
Although it is naturally smaller than that of -N, generally speaking, TAK has a degree of polymerization that corresponds to most TAK-D.
-N can be produced by culturing microorganisms. There is no substantial difference between TAK-N and TAK-D as long as they have the same average degree of polymerization. The manner in which TAK-D is produced from TAK-N will be explained below using experimental examples. Experimental Example 1 (Hydrolysis with sulfuric acid) 60 g of TAK-N (average degree of polymerization 540, measured by the method of Manners et al. Unless otherwise specified, the same method was used hereinafter) was suspended in 4N sulfuric acid 6 and heated at 60°C.
The hydrolysis reaction was carried out in a constant temperature water bath with stirring. After 30 minutes and 1 hour, collect two reaction solutions each (each reaction solution is designated as S ₁ and S ₂ in order),
The remaining mixture was further reacted for 1 hour to obtain reaction solution _S3 .
Degradation product samples were prepared from S ₁ , S ₂ , and S ₃ by the following operations. First, collect the precipitate by centrifugation, repeat the washing with distilled water in Step 1.6 and centrifugation twice, suspend it again in distilled water in Step 1.2, neutralize it by adding 8N sodium hydroxide solution, and freeze-dry it to form a powder. 22g, 20g and 19g were obtained. Next, 7 g of each of these powders were suspended in 700 ml of distilled water, the pH was adjusted to 12.5 with 8N sodium hydroxide solution, and solution S ₁ ′,
We obtained S ₂ ′ and S ₃ ′. Add ethanol to S ₁ ′, S ₂ ′ at final concentration
After removing the resulting precipitate, add ethanol to 70% and neutralize with dilute hydrochloric acid to form a precipitate.
After repeated washing four times with water and freeze-drying, 1.8 g of white powder from S ₁ ' and 1.5 g of white powder from S ₂ ' (referred to as S- and S-, respectively) were obtained.
Add ethanol to _S3 ' to a final concentration of 70%, collect the precipitate by centrifugation, suspend it again in approximately 500 ml of distilled water, add ethanol to a final concentration of 70%, and neutralize with a small amount of hydrochloric acid. A precipitate was generated by doing this. This precipitate was collected by centrifugation, washed four times with 250 ml of distilled water, and then freeze-dried, resulting in a white powder (S-) of 5.6
g was obtained. The physicochemical characteristic values of S-, S-, and S- were as shown in Table 1.

[Table] Experimental Example 2 (Hydrolysis with formic acid) (i) 6 g of TAK-N (average degree of polymerization 540) was dissolved in 85% formic acid.
It was dissolved in 150 ml and subjected to hydrolysis reaction at 88°C for 20 minutes. After cooling, the reaction solution was concentrated to dryness, the concentrate was suspended in water, and then diluted with 5N sodium hydroxide solution.
Dissolve to pH12.5 and adjust pH again with 5N hydrochloric acid.
After correcting to 7.0, the precipitate was collected by centrifugation. The precipitate was thoroughly washed with distilled water and then freeze-dried to obtain 5.4 g of white powder (F-). (ii) 12g of TAK-N used in (i) in 300ml of 90% formic acid
From the reaction solution that was hydrolyzed at 95°C for 20 minutes, 10.3g of white powder (F-) was obtained by the same operation as in (i). (iii) 12g of TAK-N used in (i) in 400ml of 90% formic acid
From the reaction solution that was hydrolyzed at 95° C. for 40 minutes, 5.4 g of white powder was obtained by the same operation as in (i). Add this powder to 0.05N sodium hydroxide solution at a final concentration of 1.0%.
The mixture was dissolved to give a precipitate by adding ethanol to 57.5%. This precipitate was collected by centrifugation, suspended in distilled water, neutralized with dilute hydrochloric acid, thoroughly washed with 70% ethanol water, and then freeze-dried to obtain 2.2 g of white powder (F-). In addition, after collecting the ethanol precipitate, ethanol is further added to the supernatant liquid to 70%, neutralized with hydrochloric acid to form a precipitate, which is then centrifuged, washed with 70% ethanol water, and freeze-dried to produce a white color. 2.3 g of powder (F-) was obtained. Furthermore, since a considerable amount of partially hydrolyzed product existed in a dissolved state in the remaining supernatant after collecting the first 5.4 g of precipitate from the hydrolysis reaction solution, this supernatant was concentrated and centrifuged. The precipitate and supernatant were separated by separation, and the former was freeze-dried to obtain 2.9 g of white powder (F-).
The latter was also gel-filtered using a Sephadex G-25 column (solvent 0.1M ammonium bicarbonate).
After fractionation, it is lyophilized to produce a white powder (F-).
0.7g was obtained. (iv) 18g of TAK-N used in (i) in 450ml of 90% formic acid
The reaction mixture was hydrolyzed at 95°C for 40 minutes and then subjected to the same operations as in (iii), such as concentration, alcohol precipitation, and gel filtration, to obtain four types of white powders (F-2.3g, F-
2.8g etc.) was obtained. F-, F-, F-, F- obtained here
, F-, F-, F-, and F- were as shown in Table 2. In addition, among these, F- or less 6 with a small degree of polymerization
The specimens were dissolved in 0.02N sodium hydroxide solution and gel-filtered under the same conditions using a Sephadex G-200 column that had been previously treated with the same solution. The samples were eluted in order (from F- to F-) forming symmetrical elution images, and it was shown that the degree of polymerization of each sample was normally distributed around the average degree of polymerization.

[Table] The present inventors have discovered that by carboxymethylating TAK-N and TAK-D, a new derivative (CMTAK) in which the hydroxyl groups thereof are carboxymethylated is generated. The present invention is based on this discovery, and the general formula (In the formula, at least one R is a -CH ₂ COOH group,
If there is a remainder, it indicates H, and n indicates an integer. The antitumor agent contains a β-1,3-glucan derivative or a salt thereof, and the above-mentioned derivative or salt thereof. CMTAK is TAK-N and TAK-
It can be obtained by carboxymethylating D by a known method. The carboxymethylation can be carried out, for example, by reacting TAK-N or TAK-D with monochloroacetic acid in the presence of an alkali. In addition, all methods commonly used for carboxymethylating sugars can be used. To collect CMTAK from the reaction mixture,
Not only can common techniques used for sugar purification, such as precipitation by addition of organic solvents, be used, but
Depending on the content of carboxymethyl groups in CMTAK or the degree of water solubility of CMTAK, techniques such as ion exchange chromatography or gel filtration can be used as appropriate. CMTAK thus obtained contains a carboxymethyl group in its molecule, but the content of this group varies widely depending on the conditions of the carboxymethylation reaction. When determined by neutralization titration, it is obtained by a conventional carboxymethylation reaction.
The carboxymethyl group content in CMTAK is generally
3 per glucose residue in the CMTAK molecule
within 100 yen. CMTAK referred to in the present invention is TAK
The molecules obtained by carboxymethylating -N or TAK-D contain all detectable carboxymethyl groups, regardless of the degree of carboxymethylation. As is clear from the above general formula shown as a free acid, CMTAK easily reacts with various bases to form their salts, such as sodium,
Forms potassium, calcium, aluminum, magnesium, amine salts, etc. of the present invention
CMTAK includes the free acid form as well as its salts, especially non-toxic salts. Table 3 shows the inventors' TAK-N and TAK
- D shows the physical properties of representative CMTAKs prepared by the above method. For all measurements of these physical properties, samples were prepared in advance at 60°C under reduced pressure over phosphorus pentoxide using a microsample dryer.
I did this after drying for 10 hours. CMTAK in the same table
Nos. 1-11 correspond to the products obtained in Examples 12-22, respectively.

[Table] In addition, the above table No. 2 and No. 1 are shown in Fig. 1 and Fig. 2, respectively.
The infrared absorption spectra of 11 CMTAKs are shown. CMTAK obtained as described above has an average degree of polymerization ranging from 565 or more to about 7, and can be used in warm-blooded animals such as humans, livestock, poultry, dogs, cats, rabbits, rats, and mice. It exhibits excellent suppressive effects on various types of tumors, especially solid tumors, which have been noted to be difficult to treat. The dose of CMTAK may be any amount that can effectively inhibit the target tumor, and may vary depending on, for example, the type of agent, target animal, tumor symptoms, administration route, dosage form, etc. Generally, a single dose is about 0.2-2000 mg/Kg body weight, with the upper limit preferably being about 500 mg/Kg, more preferably about 200 mg/Kg, and in the case of injections, the upper limit is about 100 mg/Kg. /Kg in many cases. The frequency of administration can be appropriately selected within the range of once to six times a day. Sarcoma 180 tumor transplanted into mice, SN-36
The growth of tumors such as MM-46 tumor, CCM adenocarcinoma, NTF reticulosarcoma, and Ehrlichi tumor
is administered intraperitoneally, intravenously, subcutaneously, or orally, before, after, or at the same time as tumor cell transplantation, once or repeatedly, at a dose of about 1-1000 mg/Kg per time. This was significantly suppressed. The toxicity of CMTAK is extremely low; for example, in acute toxicity tests, the LD ₅₀ values when administered orally and intraperitoneally to mice or rats were 5 g/Kg or more and 2 g/Kg, respectively, making it safe for repeated administration to humans. can do. As the administration method, common methods for tumor treatment can be applied. It can be injected subcutaneously, intramuscularly, or if necessary intravenously, orally, intrarectally, applied externally, or infused. The dosage and administration schedule can be appropriately selected in consideration of the patient, tumor type, symptoms, etc. For example, in the case of injections, 1-
About 2000 mg/Kg, preferably about 3-500 mg/Kg. CMTAK can also be used in combination with other antitumor agents. Combinations that result in enhanced immunological effects are particularly effective. Next, examples of the present invention will be shown. Some of these examples demonstrate the effectiveness of the antitumor agent of the present invention using animal models. It is well known that the effects in these animals are also reproduced in other warm-blooded animals. In other cases, CMTAK
The manufacturing method and physical properties thereof, as well as some of the administration forms of the antitumor agent of the present invention are shown. Of course, the invention is not limited to these examples. Example 1 6 × 10 ⁶ Sarcoma 180 tumor cells were transplanted subcutaneously in the right inguinal region of ICR-JCL mice with an average body weight of 23 g, and 24 hours after transplantation, the cells were produced according to Example 12.
Various doses of CMTAK were administered intraperitoneally once a day for 10 consecutive days. Tumors were excised on the 35th day after transplantation, their weights were measured, and the tumor inhibition rate was calculated by comparing with that of the non-administered control group. The sample was ground in a mortar, dissolved in distilled water for injection, and autoclaved (120℃, 25 minutes).
It was completely sterilized and administered. As shown in Table 4,
Tumor growth was suppressed at a single dose of CMTAK of 1-40 mg/Kg, and it was observed that the suppressive effect was more pronounced at a lower dose than the original TAK-N.

[Table] Example 2 A sample obtained by dissolving CMTAK obtained in Example 12 in distilled water for injection was completely sterilized by heating under pressure at 120°C for 25 minutes using an autoclave. As a result of testing the samples according to the method of Example 1, as shown in Table 5, remarkable antitumor effects were observed in all samples.

[Table] Example 3 CMTAK obtained in Example 12 was dissolved in distilled water for injection and completely sterilized in an autoclave.
3mg, 5mg, 10mg, 20mg, 400mg or 80mg once a day
ICR-JCL with an average weight of 23g for 5 consecutive days in mg/Kg
It was administered intraperitoneally to mice. Twenty-four hours after the final administration, 6 x ¹⁰⁶ Sarcoma 180 tumor cells were implanted subcutaneously in the right inguinal region, and the tumor weight was measured on the 35th day after implantation. As shown in Table 6, Tumor growth was also markedly suppressed.

[Table] Example 4 4×10 ⁶ Sarcoma 180 tumor cells were subcutaneously transplanted into the axillary region of ICR-JCL mice weighing 20-24 g.
From the 7th day after transplantation when the tumor has completely engrafted
CMTAK was intraperitoneally administered at 10 mg/Kg each time 9 times every other day. The tumor weight was measured on the 26th day after transplantation, and the tumor inhibition rate was calculated by comparing it with that of the non-administered control group. As CMTAK, those obtained in Examples 12, 15, and 16 were used, and each was dissolved in physiological saline and administered. As shown in Table 7, all samples showed a remarkable tumor growth inhibiting effect.

[Table] Example 7 3.1 × 10 ⁶ Ehrlichi carcinoma tumor cells were implanted subcutaneously in the right inguinal region of ICR-JCL mice with an average weight of 23 g, and CMTAK obtained in Example 12 was dissolved in distilled water for injection. Completely sterilized in an autoclave, then injected once a day starting 24 hours after transplantation.
mg/Kg or 40 mg/Kg was administered intraperitoneally for 10 consecutive days. The tumor was excised on the 35th day after transplantation, its weight was measured, and the tumor inhibition rate was calculated. The results are shown in Table 8, with a single dose of CMTAK of 20-40 mg/Kg.
tumor growth was suppressed.

[Table] Example 6 1.1×10 ⁷ CCM adenocarcinoma cells were transplanted subcutaneously in the right inguinal region of ICR-JCL mice with an average weight of 23 g.
The CMTAK obtained in step 12 was dissolved in distilled water for injection, sterilized in an autoclave, and then intraperitoneally administered once a day for 10 days starting 24 hours after transplantation at a dose of 20 mg/Kg each time. . The tumor was excised on the 35th day after transplantation, its weight was measured, and the tumor inhibition rate was calculated. As shown in Table 9, tumor growth was significantly suppressed.

[Table] Example 7 Four types obtained in Examples 14, 18, 20 and 22
Each CMTAK was dissolved in physiological saline and tested for its effect on Sarcoma 180 tumor according to the method of Example 1.
Continuous administration of mg/Kg for 10 days showed a remarkable growth-inhibiting effect. Example 8 CMTAK 150mg Lactose 48mg Magnesium stearate 2mg A total of 200mg or more per capsule. CMTAK and lactose are mixed in the above ratio, compressed into tablets, crushed, and mixed with magnesium stearate. Fill each No. 2 capsule with the mixture. Example 9 CMTAK 400mg Lactose 95mg HPC-L (oxypropyl cellulose)
5mg A total of 500mg or more is considered as one dose unit. After mixing the three components in the above proportions, a small amount of water is added, kneaded in a kneading machine, sized, dried, sized again, sieved, and packaged into the units mentioned above. Example 10 Dissolve 2 g of CMTAK (product of Example 20) in 100 ml of distilled water for injection (or physiological saline), filter,
Dispense the liquid into ampoules in 20 ml portions, melt and sterilize by heating in the usual manner. Example 11 CMTAK 160mg Sorbit 200mg Carboxymethylcellulose Sodium
Mix 10mg polysorbate 80 3.2mg methyl paraoxybenzoate 4mg propyl paraoxybenzoate 0.4mg or more with distilled water for injection (if using CMTAK, neutralize with N/10 sodium hydroxide solution if necessary) and add the entire amount. The volume should be 4 ml. Example 12 3 g of TAK-N (average degree of polymerization 540) was suspended in 80 ml of isopropanol, stirred at room temperature for 30 minutes, and then added with 8 ml of 30% sodium hydroxide solution while stirring.
was added slowly over about 60 minutes, and the mixture was vigorously stirred at room temperature for about 90 minutes to prevent the formation of a gel-like substance. Then add 3.6g of monochloroacetic acid,
The carboxylation reaction was carried out by stirring at 60-70°C for 5 hours. Take the product, wash thoroughly with methanol-acetic acid mixture (7:3 (V/V)), collect the precipitate by filtration, and wash thoroughly with 80% methanol water, methanol, and acetone repeatedly in that order. Thereafter, it was dried under reduced pressure to obtain 2.9 g of CMTAK.
Carboxymethyl group content (number of carboxymethyl groups per glucose residue, same hereinafter) 0.54. Example 13 1.5 g of TAK-N (average degree of polymerization 540) was suspended in 40 ml of isopropanol and stirred at room temperature for 30 minutes.
Add 0.5ml at a time in 4 parts every minute,
Stirred for an additional 90 minutes at room temperature. Next, 0.9 g of monochloroacetic acid was added in three portions of 0.3 g every 10 minutes, and the mixture was stirred at 50° C. for 150 minutes to carry out a carboxymethylation reaction. The product is collected by centrifugation,
It was dissolved in 50 ml of water and neutralized with acetic acid. Add 120 ml of methanol to this neutralized solution, collect the resulting precipitate by centrifugation, wash thoroughly with 300 ml of 80% methanol water and 100 ml of ethanol, then with a mixture of 300 ml of 80% ethanol water and 200 ml of ethanol, and freeze. After drying, 1.7 g of CMTAK was obtained. Carboxymethyl group content 0.75. Example 14 1.5 g of TAK-N (average degree of polymerization 540) was suspended in 40 ml of isopropanol, stirred at room temperature for 30 minutes, and then 4 ml of 30% sodium hydroxide solution was added to 1.5 g with stirring.
The mixture was added in 4 portions, 1 ml each at minute intervals, and stirred for an additional 90 minutes at room temperature. Next, 1.8 g of monochloroacetic acid was added in three portions of 0.6 g every 10 minutes, and the mixture was stirred at 50° C. for 150 minutes to carry out a carboxymethylation reaction. The product is collected by centrifugation,
It was dissolved in 40 ml of water and neutralized with acetic acid. 90 ml of methanol was added to this neutralized solution, and the resulting precipitate was collected by centrifugation and thoroughly washed first with a mixture of 200 ml of 80% methanol water and 100 ml of ethanol, and then with a mixture of 200 ml of 80% ethanol water and 200 ml of ethanol. Later freeze-dried and CMTAK2.0
I got g. Carboxymethyl group content 1.07. Example 15 3.2 g of TAK-N (average degree of polymerization 255) was suspended in 33 ml of water, and 1 g of sodium hydroxide was added while stirring at room temperature.
After adding 2.4g of sodium monochloroacetate
was added and stirred at room temperature for 2 hours to carry out a carboxymethylation reaction. After that, 1 g of sodium hydroxide and 2.4 g of sodium monochloroacetate were added again, and the reaction was carried out by stirring at room temperature for 3 hours. Then, 1 g of sodium hydroxide and 2.4 g of sodium monochloroacetate were further added, and the mixture was stirred at room temperature for 2 hours. The reaction was continued. Add 1 part of ethanol to the reaction solution, wash the resulting precipitate thoroughly with ethanol on a glass filter until the solution no longer turns red due to phenolphthalene, and then remove under reduced pressure.
Dry at 50°C. 3.7 g of the obtained powder was dissolved in 90 ml of water, neutralized with acetic acid, and then 210 ml of ethanol was added. The resulting precipitate was collected by centrifugation, washed with 80% ethanol water, and freeze-dried.
2.6 g of CMTAK was obtained. Carboxymethyl group content
0.30. Example 16 6.4 g of TAK-N (average degree of polymerization 255) was suspended in 66 ml of water, and 4 ml of sodium hydroxide was added while stirring under ice cooling.
After adding g, sodium monochloroacetate 9.6
g was added thereto, and the mixture was stirred for 2 hours under ice cooling to carry out a carboxymethylation reaction. Then again 4g of sodium hydroxide and 9.6g of sodium monochloroacetate.
After stirring for 3 hours under ice-cooling to carry out the reaction, 4 g of sodium hydroxide and 9.6 g of sodium monochloroacetate were added, and the mixture was stirred under ice-cooling for 3 hours.
The reaction was continued with stirring for an hour. Add 1 part of ethanol to the reaction solution, wash the resulting precipitate thoroughly with ethanol on a glass filter until the solution no longer turns red due to phenolphthalene, and then
Dry at 50°C under reduced pressure. Add 8.6g of the obtained powder to water.
After dissolving in 172 ml and neutralizing with acetic acid, 480 ml of ethanol was added. The resulting precipitate was collected by centrifugation, further washed with 80% ethanol water, and then freeze-dried to obtain 5.6 g of CMTAK. Carboxymethyl group content 0.36. Example 17 1.5 g of TAK-D (F-, average degree of polymerization 299) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 13. The reaction product was washed to obtain 1.9 g of CMTAK. Carboxymethyl group content 0.59. Example 18 1.5 g of TAK-D (F-, average degree of polymerization 299) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 14. Next, the reaction product was washed to obtain 2.2 g of CMTAK. Carboxymethyl group content 1.15. Example 19 1.5 g of TAK-D (F-, average degree of polymerization 113) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 13.
The product was collected by centrifugation, dissolved in 40 ml of water and neutralized with acetic acid. Add methanol 90% to this neutralizing solution.
ml and collect the resulting precipitate by centrifugation.
First with 200ml of 80% methanol water, then with 80%
After thorough washing with 200 ml of ethanol water, each was freeze-dried to obtain 1.4 g of CMTAK. Carboxymethyl group content 0.51. Example 20 1.5 g of TAK-D (F-, average degree of polymerization 113) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 14.
The reaction product was washed as in Example 19.
Obtained 2.3 g of CMTAK. Carboxymethyl group content
1.22. Example 21 1.5 g of TAK-D (S-, average degree of polymerization 68) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 13.
The reaction product was washed as in Example 19.
1.4 g of CMTAK was obtained. Carboxymethyl group content
0.36. Example 22 1.5 g of TAK-D (S-, average degree of polymerization 68) was suspended in 40 ml of isopropanol, and a carboxymethylation reaction was carried out in the same manner as in Example 14.
The reaction product was washed as in Example 19.
1.4 g of CMTAK was obtained. Carboxymethyl group content
0.45.

[Brief explanation of the drawing]

Figures 1 and 2 are CMTAK in Table 3, respectively.
The infrared absorption spectrum curves of No. 2 and No. 11 are shown.

Claims (1)

[Claims] 1. General formula (At least one R in the formula is a -CH ₂ COOH group,
If there is a remainder, it indicates H, and n indicates an integer. The average degree of polymerization of the compound is from 2 to 1000).
1,3-glucan derivatives and salts thereof. 2 General formula (At least one R in the formula is a -CH ₂ COOH group,
If there is a remainder, it indicates H, and n indicates an integer. The average degree of polymerization of the compound is from 2 to 1000).
An antitumor agent containing a 1,3-glucan derivative or a salt thereof.