RU2801042C2 - Crystalline form of 4-[2-(1h-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, a method of its production, pharmaceutical compositions based on it, its use as an antiviral agent, a method of its identification in pharmaceutical products - Google Patents

Abstract

FIELD: pharmaceuticals.

SUBSTANCE: invention relates to crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid characterized by a diffraction pattern with a set of maxima at an angle of 2θ: 8.51±0.2, 8.76±0.2, 11.39±0.2, 15.48±0.2, 17.03±0.2, 17.55±0.2, 17.77±0.2, 18.31±0.2, 19.05±0.2, 19.21±0.2, 19.73±0.2, 20.23±0.2, 21.26±0.2, 21.78±0.2, 22.56±0.2, 23.86±0.2, 24.32±0.2, 25.50±0.2, 26.05±0.2, 27.07±0.2, 28.22±0.2, 29.13±0.2, 29.5±0.2, 30.11±0.2, 31.22±0.2, 31.76±0.2, 37.2±0.2, 38.14±0.2, 40.25±0.2, 41.33±0.2, 41.94±0.2. Crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic according to the invention is used as the active substance of a solid oral dosage form for the prevention and treatment of viral diseases. The invention also relates to a method of identifying 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to the invention in a solid oral dosage form, characterized by the use of X-ray phase analysis, infrared spectroscopy and differential scanning calorimetry, in which the content of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the solid dosage form must be at least 10% by weight of a solid dosage form.

EFFECT: obtaining 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a new crystalline form I with improved technological properties for the production of solid dosage forms on its basis, in a more accessible and cheap way with a high yield, the said form has antiviral activity, increased stability of pharmaceutical formulations, the ability to identify the content of form I in solid dosage forms.

13 cl, 8 dwg, 12 tbl, 5 ex

Description

Technical field

The invention relates to pharmaceutical chemistry and pharmaceutical industry, concerns a new crystalline form of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, a method for its production, new pharmaceutical compositions based on it, their use in as an antiviral, anti-inflammatory and immunomodulatory agent, and a method for identifying the content of a new crystalline form in manufactured pharmaceutical products.

Prior Art

4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid has the structural formula (I) and is used for antiviral prophylaxis and therapy.

The mechanism of action of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is associated with the stimulation of innate immunity factors that are suppressed by viruses. It increases the expression of the type 1 interferon receptora IFNAR on the surface of epithelial and immunocompetent cells, which leads to an increase in the density of interferon receptors and to an increase in the sensitivity of cells to endogenous interferon signals. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid stimulates the production of the antiviral effector protein MxA, which inhibits the intracellular transport of ribonucleoproteins of various viruses, slowing down the process of viral replication. It stimulates and normalizes the reduced α-interferon producing ability of blood leukocytes, stimulates γ-interferon producing ability of leukocytes. Causes the generation of cytotoxic lymphocytes and increases the content of NK-T cells, which are highly active against virus-infected cells. The anti-inflammatory effect is due to the suppression of the production of key pro-inflammatory cytokines (tumor necrosis factor (TNF-α), interleukins (IL-1β and IL-6)), a decrease in the activity of myeloperoxidase (V.V. Zarubaev, A.V. Garshinina, N.A. Kalinina wt al. Activity of Ingavirin (6 -[2-(1H-Imidazol-4-yl)ethylamino]-5-oxohexanoic Acid) Against Human Respiratory Viruses in in Vivo Experiments Pharmaceuticals 2011, 4, 1518-1534; doi:10.3390/ph4121518).

Polymorphism - the ability of a substance to exist in different crystalline forms with the same chemical composition. Such forms are called polymorphic modifications. Polymorphs exhibit various physical and physicochemical properties, such as melting point, crystal size, density, solubility and dissolution rate, specific heat, electrical conductivity, contact angle, refractive index, light scattering coefficient, IR spectra, Raman spectra, thermograms , X-ray diffraction patterns, etc. (State Pharmacopoeia of the Russian Federation. XIV edition. General pharmacopoeial article. 1.1.0017.15. Polymorphism. S. 393-396).

The polymorphism of medicinal substances is of great importance for the chemical-pharmaceutical industry, since the difference in physico-chemical properties can affect the therapeutic efficacy of drugs. (Smirnova I.G., Gildeeva G.N., Chistyakov V.V. Analysis of the crystal and spatial structure of medicinal substances // Bulletin of Moscow University. Series 2. Chemistry. - 2012. - V. 53. - No. 4. P. 234-240).

Obtaining more stable crystalline forms of medicinal substances with improved technological, physicochemical and biopharmaceutical characteristics, which can lead to an increase in the effectiveness and shelf life of drugs, is an important task for the pharmaceutical industry and medicine.

Two polymorphs A and B are known from CN103382179A for 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid.

Crystal Form A from CN103382179A has an X-ray diffraction pattern obtained at Cu-Kα with the following 2θ angles: 16.25388; 17.55537; 18.19366; 18.74863; 19.78359; 20.20446; 22.27632; 24.14684; 24.38282; 24.93973; 25.34327; 26.41213; 26.93823; 27.06627; 28.01838; 28.62621; 28.94396; 29.92034; 32.30439; 33.21582; 34.69475; 37.98252; 38.51969; 39.85372; 42.54231. Form A from CN103382179A has characteristic peaks in the IR spectrum at 3163, 3100, 3007, 2868, 2005, 1463, 1269, 1200, 1138 and 948 cm ^-1 .

Crystal form A from CN103382179A is obtained in the following way: dissolve 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a solvent at a temperature of from -40 to -180 ° C at a ratio of 1 g of substance to 1- 50 ml of solvent, at a temperature of -40 to -50°C, cooled 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is separated, filtered and dried at a temperature of 30-100°C.

In more detail in example 1 CN103382179A, crystalline form A is obtained by dissolving 2 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 14 ml of water, adding 60 ml of acetone, separating the opalescent precipitate, stirring for 2 h on an ice bath, filtering the resulting precipitate and washing it with acetone 2 times. The output of form A - 1.4 g (70%).

In more detail in example 2 CN103382179A, crystalline form A is obtained by dissolving 3 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 50 ml of methyl alcohol, while stirring, adding 25 ml of triethylamine dropwise, slowly adding 360 ml of ethyl acetate, cooling to 0°C, stirring for 2 hours, filtering the precipitate formed, washing the precipitate on the filter with 100 ml of ethyl acetate, drying under reduced pressure. Form A yield - 1.94 g (64.7%).

Crystal Form B from CN103382179A has an X-ray diffraction pattern obtained at Cu-Kα with the following 2θ angles: 15.48400; 17.03720; 17.64442; 17.83801; 19.08664; 20.24814; 21.25388; 21.83913; 23.93256; 24.27171; 25.48872; 26.98308; 29.09590; 30.12190; 41.31897. Form B from CN103382179A has characteristic peaks in the IR spectrum at 3066, 2971, 2932, 2857, 2802, 2005, 1777, 1300, 1234, 1216, 1196, 1129, 1086, 1051, 1033, 933 , 811, 740 and 588 cm ^-1 .

Crystalline form B from CN103382179A is obtained in the following way: dissolve 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a solvent at a temperature of from -40 to -180 ° C at a ratio of 1 g of substance to 1- 50 ml of solvent, at a temperature of -40 to -50°C, cooled 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is separated, filtered and dried at a temperature of 30-100°C.

In more detail in example 3 CN103382179A, crystalline form B is obtained by dissolving 2 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 28 ml of water:ethanol=1:1, stirring at room temperature in during 24 h, filtering the formed precipitate and washing it with ethanol 2 times. The yield of form B is 1.2 g (60%).

In more detail, in example 4 CN103382179A, crystalline form B is obtained by dissolving 2 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in methyl isobutyl ketone/dimethyl sulfoxide, stirring at room temperature for 24 h, filtering the resulting precipitate and washing with methyl isobutyl ketone 2 times. The yield of form B is 1.5 g (75%).

Forms A and B of CN103382179A were tested for stability for 10 days at 60° C., 92.5% humidity and were higher than the commercially available product.

These forms A and B of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid from CN103382179A and methods for their preparation have a number of significant drawbacks:

1) The general description of the methods for obtaining each of the forms A and B, presented in the claims, is completely identical. Therefore, the formation of different forms A and B of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid cannot follow from identical preparation methods.

2) The description of the methods for obtaining forms A and B in the examples does not correspond to the general description of the methods given in the claims.

3) The general method for obtaining forms A and B, presented in the formula, is carried out at very low temperatures and requires specialized equipment and the consumption of cooling agents.

4) Low yield of products, not exceeding 70% for form A and 75% for form B.

5) Conducted stability testing for 10 days at 60°C and 92.5% humidity is not enough to confirm the shelf life of the drug for at least 1 year; The study was performed on a dosage form in the form of a capsule of unknown composition.

Disclosure of invention

The objective of the present invention is to overcome these disadvantages and obtain a new crystalline form of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid (the authors designated as form I) in a simple and more efficient way of obtaining, which is technologically more suitable to obtain solid and liquid dosage forms based on it, which have antiviral activity, an extended shelf life of up to 4 years and develop a method for identifying the state of the crystalline form during the entire shelf life.

This problem is solved by a new crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, as well as a method for its preparation.

The technical result of the invention is: obtaining a more accessible and cheap way with a high yield of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the form of a new crystalline form I, with improved technological properties for the production of solid and liquid dosage forms based on it, which has antiviral activity comparable to that of a commercial product, and in some cases surpassing it; composition of pharmaceutical compositions based on form I, their increased stability and consequently increased shelf life of more than 5 years; the possibility of identifying the content of form I in solid dosage forms.

Crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid has a characteristic set of maxima and their intensities on the diffraction pattern (Fig. 1,2). Form I is characterized by a set of maxima at an angle of 2θ: 8.51±0.2, 8.76±0.2, 11.39±0.2, 15.48±0.2, 17.03±0.2, 17.55±0.2, 17.77±0.2 , 18.31±0.2, 19.05±0.2, 19.21±0.2, 19.73±0.2, 20.23±0.2, 21.26±0.2, 21.78±0.2, 22.56±0.2, 23.86 ±0.2, 24.32±0.2, 25.50±0.2, 26.05±0.2, 27.07±0.2, 28.22±0.2, 29.13±0.2, 29.5±0.2, 30.11±0 ,2, 31.22±0.2, 31.76±0.2, 37.2±0.2, 38.14±0.2, 40.25±0.2, 41.33±0.2, 41.94±0.2. On FIG. 1 shows the X-ray diffraction pattern of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid form I in the range from 3 to 70 deg 2θ. On FIG. Figure 2 shows the same diffraction pattern with increased resolution in the range from 5 to 45 deg 2θ for the convenience of its further analysis.

Only those maxima that exceeded the instrumental background value by a factor of 3 were considered characteristic maxima in the diffraction pattern. The average background value on the diffractograms was 80 pulses; accordingly, those maxima were chosen as characteristic, the intensity of which exceeded 240 pulses. Normalization of the intensity of the maxima was carried out according to the most intense maximum at an angle of 23.86 deg 2θ, which was taken as 100%.

Comparative analysis of the diffraction maxima of form I and form A from CN103382179A, which is the closest in structure, is shown in Table 1. All characteristic maxima and their intensities are marked in the table. The analysis of coinciding maxima was carried out according to the following scheme:

1. In accordance with generally accepted rules among specialists in diffraction analysis, it was considered that the maxima on the diffraction pattern coincide if the difference in the values of the angle 2θ differs by no more than ±0.2 deg. In the case of such a coincidence of the angle 2θ, the table indicated that "there is" a match.

2. It was considered that the intensities of the maxima coincide if the discrepancy in the intensity of the maximum did not exceed ±50% of the tabular values for form A given in CN103382179A. In the case of such a coincidence of intensity, the table indicated that "there is" a match. The value of ±50% was chosen based on the possible large error in determining the intensity for samples with different morphology.

3. If the diffraction maximum for form A from CN103382179A does not coincide with any of the maxima of the new form I in the range of ±0.2 deg 2θ, then in this case it was noted that there was “no” coincidence and for such a maximum the intensities were not compared.

Thus, a comparative analysis of the positions of the maxima in the diffraction pattern and their intensities of the new form I and form A showed that:

1. Form I is characterized by a diffraction pattern containing 31 characteristic diffraction maxima, form A - 25 maxima.

2. Characteristic maxima in form I start at 8.51 deg 2θ, characteristic maxima in form A start at 16.25388 deg 2θ.

3. Among the 31 characteristic diffraction peaks in shape I, only three diffraction peaks with shape A coincided simultaneously in the position of the angle 2θ and intensity.

4. Among the 31 characteristic diffraction peaks in shape I, 10 diffraction peaks coincided with shape A only in the position of the angle 2θ.

Thus, the comparative analysis of the positions of the maxima in the diffraction pattern of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid confirmed that a new previously unknown form I was obtained, which is characterized by its own set of characteristic maxima in the diffraction pattern (Fig. 1,2).

The crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is characterized by an IR spectrum which contains 34 main absorption maxima at 3240, 3147, 3097, 3003, 2965, 2853, 2793, 2649 1640 1562 1476 1454 1416 1379 1332 1302 1271 1211 1193 1123 1086 1066 1048 1031 933 880 836 805 761 , 741, 708, 666, 655 and 637 cm ^-1 (Fig. 3). The most intense maximum in the IR spectrum is at 637 cm ^-1 , which is absent in form A and B of CN103382179A.

Crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is characterized by a DSC-TGA thermogram (Fig. 4). The melting point of form I is 201°C. There is no weight loss up to the melting temperature, which indicates the absence of solvated solvent molecules in the crystal structure of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid form I.

Confirmation of the preservation of the structure of the molecule in crystalline form I is the analysis of ¹ H NMR (Fig. 5), which turned out to be identical before and after the process of obtaining crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]- butanoic acid.

The method for obtaining 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I consists in dissolving 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a solvent , in which it is possible to achieve a concentration of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid 7-15% of the mass. and more and further slow evaporation of the solution under vacuum until the solvent is completely removed.

Elevated concentrations of a solution of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid can be achieved by heating the solution while stirring until all the precipitate of the substance dissolves and the solution becomes completely transparent.

It was found that form I is formed at a rate of evaporation of a concentrated solution of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid of 0.05-0.5% by weight of the total solvent in one minute of the process. Heating of the solution during the evaporation process is allowed if the rate of solvent removal is within this range. The evaporation temperature of the solution should be in the range from 25 ° C to the boiling point of the solvent minus 10-15 degrees, i.e. the solution should not boil. In the fluidized bed of the solution, the formation of nuclei of another crystalline phase is initiated, which leads to the formation of a significant proportion of impurities. The time of the evaporation process can be from 200 to 2000 minutes, depending on the volume of the solvent, the depth of the vacuum and the temperature of the solution. The yield of form I is not less than 98%.

As a solvent, it is recommended to use water, dimethyl sulfoxide or mixtures thereof in various proportions. It is preferable to use a mixture of water/dimethylsulfoxide in a ratio of 20:1 to 2:1 by volume.

The advantage of this method is the ease of implementation, the use of standard laboratory and industrial equipment, the ability to control the temperature, pressure and evaporation rate in a wide range, the single-stage process without the need for cooling, filtering and additional washings, as well as a high product yield.

Another object of the invention is the use of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I for the prevention and treatment of viral diseases.

It was found that the use of a therapeutically effective amount of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I in an in vivo experimental model (ferrets) effectively and significantly reduces the clinical manifestations of influenza infection, such as sneezing, respiratory failure, decreased activity. As indicators of effectiveness in the experiment, we used the clinical picture of the disease, the dynamics of changes in body temperature, macro- and microscopic changes in the lungs, the cellular composition of nasal swabs, and a clinical blood test. Crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid for the prevention and treatment of viral diseases was used both separately and as part of a pharmaceutical composition with a set of pharmaceutically acceptable additives. Such use includes administering a therapeutically effective amount of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I orally in solid or liquid dosage forms, which may be tablets, capsules, powder, aqueous solution or syrup. Pharmaceutically acceptable additives are any substances that are approved for use by regulators in different countries for the creation of dosage forms based on them.

In another embodiment of the invention, to further enhance the antiviral effect, it is possible to use 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I with other substances having antiviral activity.

Such use includes administering a therapeutically effective amount of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I and known antiviral agents orally in solid or liquid dosage forms.

In specific embodiments, the known antiviral agent is selected from the group consisting of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or combinations thereof.

Another object of the invention is a pharmaceutical composition for the treatment and/or prevention of viral diseases, containing a therapeutically effective amount of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I and a set of pharmaceutically acceptable additives.

In another embodiment of the invention, to further enhance the antiviral effect, the pharmaceutical composition may contain an additional known active substance with antiviral activity.

In specific embodiments, the known antiviral agent is selected from the group consisting of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or combinations thereof.

The most convenient for the use of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I are solid dosage forms in the form of tablets, capsules or powder containing a therapeutically effective amount of form I.

A therapeutically effective amount of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I in solid dosage forms is from 30 to 90 mg.

For oral administration, liquid dosage forms can be used, which are prepared by dissolving the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in aqueous solutions or syrups.

Syrups may contain sugar, glycerol, botanicals, thickeners, acidifiers, colors, flavors, and other pharmaceutically acceptable additives used for these purposes.

The dosage of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I in aqueous solutions or syrups is 6 to 18 mg/ml.

All pharmaceutical compositions used are administered orally.

Another object of the invention is a method for monitoring or a method for identifying or a method for detecting crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in solid dosage forms by X-ray phase analysis, infrared spectroscopy and differential scanning calorimetry .

The method consists in applying these methods to analyze a solid dosage form containing a crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in an amount of at least 10% of the mass. from the mass of a single dosage form.

The method of x-ray phase analysis on a variety of compositions of pharmaceutical compositions containing crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, in an amount of at least 10% of the mass. on the mass of a single dosage form, regardless of the type of solid dosage form (tablet, capsule (internal contents of the capsule), powder) reveals four maxima at an angle of 2θ: 19.05±0.2, 20.23±0.2, 21, 26 ± 0.2, 23.86 ± 0.2, which correspond to Form I. With any composition of the pharmaceutical composition, three of these four maximums remain (Fig. 6).

Thus, confirmation that the pharmaceutical composition contains 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I is the following sets of 2θ angles on the diffraction pattern:

19.05±0.2, 20.23±0.2, 21.26±0.2;

20.23±0.2, 21.26±0.2, 23.86±0.2;

19.05±0.2, 21.26±0.2, 23.86±0.2;

19.05±0.2, 20.23±0.2, 23.86±0.2.

The use of the X-ray phase analysis method is sufficient to identify the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the composition of the pharmaceutical composition, if its amount in the composition is at least 10% of the mass.

The method of infrared spectroscopy on various formulations of pharmaceutical compositions containing crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, in an amount of at least 10% of the mass. from the mass of a single dosage form, regardless of the type of solid dosage form (tablet, capsule (internal contents of the capsule), powder) always reveals a maximum at 637 cm ^-1 , which is characteristic only for form I (Fig. 7).

The use of the infrared spectroscopy method is sufficient to identify the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the composition of the pharmaceutical composition, if its amount in the composition is at least 10% of the mass.

The simultaneous use of X-ray phase analysis and infrared spectroscopy to identify the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a pharmaceutical composition makes it possible to independently confirm the presence of form I.

The method of differential scanning calorimetry on a variety of compositions of pharmaceutical compositions containing crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, in an amount of at least 10% of the mass. from the mass of a single dosage form, regardless of the type of solid dosage form (tablet, capsule (internal contents of the capsule), powder) reveals a maximum melting point at 193±3°C (Fig. 8). This melting point method does not allow unequivocal determination that the composition contains form I, therefore this method is additional to the two methods listed above.

Description of figures

Fig. 1. Diffraction pattern of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I in the range from 3 to 70 deg 2θ.

Fig. 2 X-ray diffraction pattern of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I in the range from 5 to 45 deg 2θ.

Fig. 3. Fourier transform IR spectrum of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid form I in the range.

Fig. 4. DSC curves (1) and TG curves (2) of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid form I.

Fig. 5. ¹ H NMR spectrum of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid form I. A - full spectrum; B - enlarged fragment in the range of 1.5-3.5 ppm; C - enlarged fragment in the range of 6.5-8 ppm.

Fig. 6. X-ray diffraction pattern of a pharmaceutical composition containing crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the range from 3 to 70 deg 2θ.

Fig. 7. Fourier transform IR spectrum of a pharmaceutical composition containing 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I.

Fig. 8. DSC (1) and TG (2) curves of a pharmaceutical composition containing 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid Form I.

Description of instruments and methods for physical and chemical measurements

Powder X-ray phase analysis (XRD) was performed on a Rigaku Ultima IV diffractometer (Japan), the tube voltage was 40 kV, the tube current was 30 mA, and the tube anode material was Cu. Goniometer: Θ/Θ vertical type, the sample is stationary. Goniometer radius - 185 mm / 285 mm. The maxima in the diffraction pattern accumulated over 1 h. The angle 2Θ ranged from 3 to 70 degrees.

The melting point, thermal behavior, and weight loss were studied by differential scanning calorimetry and thermogravimetry (DSC-TGA) on a NETZSCH STA 449 C instrument (Germany) in an inert atmosphere at a heating rate of 10 deg/min.

Infrared radiation spectra (IR spectra) were obtained on a Spectrum Two IR-Fourier spectrometer (Perkin Elmer, USA) with a diffuse reflectance attachment in the range of 4000-600 cm ^-1 with a resolution of 2 cm ^-1 , the number of scans was 10.

^1H NMR spectra were obtained on a Bruker Avance NMR spectrometer (Germany) with a frequency of 600 MHz in DMSO-d6.

Stability testing (accelerated storage test) was carried out in a Memmert HCP50 chamber (Germany) at 40°C and 75% humidity in accordance with the Decision of the Board of the Eurasian Economic Commission dated May 10, 2018 No. 69 “On Approval of the Requirements for the Study of the Stability of Medicinal Products and Pharmaceutical Substances” .

Embodiments of the invention

The invention is illustrated by the following examples, but is not limited to them.

Example 1 Preparation of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I

7.0 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is slowly dissolved with stirring in 100 ml of water heated to 85°C. From the resulting hot solution with a concentration of 10%, water is slowly distilled off on a rotary evaporator (pressure 10 mm Hg) at a rate of 0.5 ml/min until the solvent is completely removed. Approximate process time was 200 min. The yield of form I is 98.0%.

Crystal form I is formed in 99.1% yield. The structure of the crystal lattice is confirmed by X-ray phase analysis (Fig. 1, 2). Form I has a characteristic IR spectrum (FIG. 3). The melting point was set to 201° C. by differential scanning calorimetry (Fig. 4). ¹ H-NMR method confirmed the preservation of the structure of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid before and after its recrystallization, the spectra were identical (Fig. 5).

Another way to obtain form I is to dissolve 200 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 1000 ml of dimethyl sulfoxide with stirring at a temperature of 25 ° C and distillation of the solvent on a rotary evaporator at 4 mm .rt.st. at a rate of 0.05 ml/min until the solvent is completely removed. The total process time was just over 33 hours. The yield of Form I was 99.5%. Physico-chemical characteristics correspond to Fig. 1-5.

Another way to prepare form I is to dissolve 50 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 500 ml of a mixture of dimethyl sulfoxide with water (1:1) with stirring at a temperature of 30°C and distillation of solvents on a rotary evaporator at 7 mm Hg. at a rate of 0.15 ml/min until the solvent is completely removed. The yield of form I is 98.7%. Physico-chemical characteristics correspond to Fig. 1-5.

Another way to obtain form I is to dissolve 50 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 500 ml of a mixture of dimethyl sulfoxide with water (1:9) with stirring and a temperature of 60 ° C and distillation of solvents on a rotary evaporator at 4 mm Hg. at a rate of 0.4 ml/min until complete removal of the solvent. The output of form I - 99.0%. Physico-chemical characteristics correspond to Fig. 1-5.

Another way to obtain form I is to dissolve 90 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 500 ml of a mixture of dimethyl sulfoxide with water (9: 1) with stirring and a temperature of 60 ° C and distillation of solvents on a rotary evaporator at 5 mm Hg. at a rate of 0.08 ml/min until the solvent is completely removed. The output of form I - 99.0%. Physico-chemical characteristics correspond to Fig. 1-5.

Another way to prepare form I is to dissolve 50 g of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in 500 ml of a mixture of dimethyl sulfoxide with water (4:1) with stirring at a temperature of 35°C and distillation of solvents on a rotary evaporator at 3 mm Hg. at a rate of 0.06 ml/min until the solvent is completely removed. The output of form I - 98.4%. Physico-chemical characteristics correspond to Fig. 1-5.

Example 2. Study of the stability of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I by the accelerated storage method

Form I in the form of a substance and a dosage form (tablets, capsules and powder) were stored (n=5) in a climatic chamber and kept for 16 months at a temperature of 40°C and a humidity of 75°C. Samples were analyzed every 2 months. The amount of the substance and its decomposition products was determined by HPLC, and the crystal form I was monitored by X-ray phase analysis. Stability data are shown in Table 2.

From Table 2 it follows that all Form I and dosage forms based on it are stable for 16 months in the accelerated storage method, which corresponds to more than 5 years of storage under normal conditions. X-ray phase analysis in each case confirmed the crystal structure of form I in the test samples, the diffractograms corresponded to Fig. 1.

Example 3 Use of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I for the treatment and prevention of viral diseases

The antiviral activity of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I (hereinafter Form I) was evaluated in a model of influenza infection in ferrets.

Since the discovery of the susceptibility of ferrets (Mustela putorius furo) to the influenza virus in the 1930s, they have remained one of the best animal models of influenza infection, as they exhibit many of the clinical symptoms seen in humans after influenza infection. Unlike mice, ferrets are naturally susceptible to human influenza virus isolates. Human and avian influenza viruses replicate efficiently in the respiratory tract of ferrets, and ferrets also exhibit the clinical signs found in humans after infection with seasonal or avian influenza virus - runny nose, fever, etc. Ferrets can be directly infected with the human influenza virus without prior viral adaptation and are capable of transmitting the influenza virus between themselves. The susceptibility of ferrets to human influenza viruses is due to the presence of terminal α2-6-linked N-acetylneuraminic sialic acids (Neu5AC) in the respiratory mucosa, which promotes virus binding and initiation of virus replication (Smith J.H., Nagy T., Driskell E., Brooks P. , Tompkins S.M., Tripp R.A. Comparative pathology in ferrets infected with H1N1 influenza A viruses isolated from different hosts // Journal of virology - 2011. - Vol. 85, No 15. - P. 7572-7581).

In the experiment, seronegative (by the presence of antibodies to the influenza A virus) male ferrets aged 6-8 months were used. The test preparations/formulations (or placebo) were administered to the animals according to the following scheme: 1 day before the infection of the animals, on the day of the infection, and then 3 days after the infection. Ingavirin ^® and Tamiflu ^® were chosen as the reference drug, which was administered orally to the animals at a daily dose of 15 mg/kg. Since preliminary experiments did not reveal differences in the effect when taking Form I in the form of a pharmaceutical substance or dosage form (capsule), then all further experiments were performed on a dosage form in the form of capsules (Table 10, example No. 1).

The highest therapeutic dose (HTD) for the commercial drug Ingavirin ^® is 90 mg per person (or 1.5 mg/kg with a weight of 60 kg).

Taking into account interspecies dose conversion factors (Guidance for industry. Estimating the maximum safe starting dose in initial clinical trials for therapeutics in adult healthy volunteers / Center for Drug Evaluation and Research (CDER), 2005), the equivalent dose (VTD) for a ferret was - 1 .5 mg/kg x5.3 (conversion factor)=7.95 mg/kg (about 8 mg/kg).

When studying antiviral activity, three doses of the drug were used - 4 mg/kg (1/2 VTD), 8 mg/kg (VTD), 16 mg/kg (2 VTD). The drugs were administered orally.

We used a strain of the pandemic influenza A virus. To infect ferrets, 0.25 ml of virus-containing material was injected into each nostril.

In the control group, infection of animals with virulent influenza A virus was accompanied by sneezing, nasal discharge, respiratory failure and decreased activity, noted already on the 2nd day after infection, an increase in body temperature up to 41°C (1-2°C above normal temperature) , the development of an acute systemic and local inflammatory response and pathomorphological changes on the 4th day after infection.

As indicators of effectiveness in the experiment, we used the clinical picture of the disease, the dynamics of changes in body temperature, macro- and microscopic changes in the lungs, the cellular composition of nasal swabs, and a clinical blood test.

During the clinical examination of the animals, symptoms from the nasopharynx, changes in breathing, and activity were recorded (Table 3).

With the maximum severity of pathological changes during clinical examination, the animal can be assigned a total score of 7 (intense nasal discharge + heavy breathing + severe depression). The severity of symptoms was recorded on an ordinal scale (points). Data are presented in Table 4.

From the data of Table 4 it follows that in all animals exposed to infection, clinical signs of the development of influenza infection were recorded, most pronounced in the control group of animals, starting from the 2nd day of the experiment. Against the background of therapeutic and prophylactic administration of the reference drug Tamiflu ^® at a daily dose of 15 mg/kg after infection of animals with virulent influenza A virus, the severity and duration of clinical symptoms, such as sneezing, respiratory failure, decreased activity, decreased.

Administration of Ingavirin ^® and Form I to ferrets at doses of 16 mg/kg and 8 mg/kg resulted in an equivalent significant reduction in the clinical manifestations of influenza infection on the 3rd and 4th day of the experiment. The use of Ingavirin ^® and Form I at a dose of 4 mg/kg did not reduce the severity of symptoms of influenza infection. Thus, Form I and Ingavirin ^® at doses of 8 and 16 mg/kg, respectively, have similar antiviral activity.

To study the effect of test preparations on the body temperature of ferrets infected with the virus.

Against the background of the introduction of the reference drug Tamiflu ^® , form I and Ingavirin ^® at doses of 8 and 16 mg/kg, there was a pronounced tendency to reduce the body temperature of ferrets infected with the virus (Table 5), while form I and Ingavirin ^® at a dose of 4 mg/kg practically did not reduce the body temperature of experimental animals. The results obtained indicate that Form I and Ingavirin ^® at doses of 8 and 16 mg/kg, respectively, have a similar tendency to reduce body temperature in experimental animals infected with the virus.

Complete blood count in ferrets exposed to the virus

Blood was taken from the cubital vein, the parameters were determined in whole blood (with anticoagulant) on a standard veterinary hematological analyzer. The data are shown in Table 6. Statistically significant changes in the leukocyte formula (in intact and control groups) were revealed, manifested in an increase in the population of granulocytes and a decrease in the population of lymphocytes in ferrets exposed to infection, which indicates the development of a systemic inflammatory reaction.

Tamiflu ^® (15 mg/kg), Ingavirin ^® and form I at doses of 16 mg/kg showed the maximum activity, manifested in a significant increase in the population of lymphocytes and a decrease in the population of granulocytes (Table 6). Form I at a dose of 8 mg/kg had a pronounced antiviral activity, while Ingavirin ^® at a dose of 8 mg/kg did not have such activity, which indicates a superior activity of form I compared to Ingavirin ^® . With the introduction of Ingavirin ^® and form I at a dose of 4 mg/kg, there was only a tendency to change the parameters of the leukocyte formula, which indicates the absence of pronounced antiviral activity.

Study of the cellular composition of nasal swabs.

Nasal swabs were taken from all animals on days 1, 2, 3, and 4 under short-term anesthesia. To collect nasal swabs, ferrets (under anesthesia) were injected with a dispenser into one nasal passage with 1 ml of phosphate-buffered saline. The number of specific cell types (granulocytes, lymphocytes and monocytes/macrophages) was calculated after the preparation of glass slides stained with May-Grunwald-Giemsa by light microscopy. At least 100 cells were counted and the percentages for each cell population were estimated (Table 7).

Infection of ferrets with the influenza virus led to the development of acute inflammation in the nasal passages, which was characterized by an increase in the population of monocytes in the mucus. Against the background of the introduction of the comparison drug Tamiflu ^® , Ingavirin ^® at doses of 16 mg/kg and 8 mg/kg, as well as Form I at doses of 16 mg/kg, 8 mg/kg and 4 mg/kg, there was a significant decrease in the monocyte population, indicating reduction of the inflammatory process. With the introduction of Ingavirin ^® at a dose of 4 mg/kg, only a tendency to reduce inflammation was observed. Thus, form I showed significant pharmacological activity at doses of 4, 8 and 16 mg/kg, while Ingavirin ^® had significant activity only at doses of 8 and 16 mg/kg, which indicates a higher activity of form I. Pathomorphological studies

On the 4th day after infection of the ferrets with the influenza virus, pathomorphological studies were performed. The pathology was assessed according to a number of criteria (Table 8), which were assigned a value corresponding to the severity of the process: 0 - no changes, 1 point - minimal changes, 2 points - minor changes, 3 points - moderately pronounced changes, 4 points - strongly pronounced changes, 5 - the most pronounced changes.

According to the results of a pathomorphological study, in all experimental groups infected with the virus, regardless of the administered test drug, inflammation was recorded affecting all lung tissues of animals.

Animals showed damage to the airways from mild to moderate bronchitis and bronchiolitis, single small areas of epithelial necrosis, mild hypertrophy and hyperplasia of the epithelial lining. Weak and moderate inflammation in the respiratory section affected the bronchi, bronchioles, vessels and alveoli in the form of lymphocytic and mononuclear infiltration. There was a reaction of the lung tissue in the form of mild and moderate hyperemia of the alveolar septa, hemorrhages and emphysema.

In the control group of animals, the severity of damage was 5 points. Against the background of therapeutic and prophylactic administration of the reference drug Tamiflu ^®, the severity of damage was 2 points. With the introduction of Ingavirin ^® at doses of 8 and 16 mg/kg, the severity of damage was moderate and was estimated at 3 points, while with the use of form I at doses of 8 and 16 mg/kg, minor damage to the respiratory system developed, estimated at 2 points. When using Ingavirin ^® and form I at a dose of 4 mg/kg, changes in the bronchopulmonary system were significantly pronounced and amounted to 4 points. Thus, form I at doses of 8 and 16 mg/kg showed a pronounced pharmacological effect comparable to the effect of the reference drug Tamiflu ^® , while Ingavirin ^® at doses of 8 and 16 mg/kg was significantly inferior in activity to form I at equivalent doses and the reference drug Tamiflu ^® .

Joint separate use or as part of a composition of an additional antiviral substance selected from the group of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir or their combinations increases the effectiveness of treatment as a whole by 10-50%, depending on the mechanism of action and dosage of the substance.

Example 4 Pharmaceutical compositions containing 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I

Variants of pharmaceutical compositions containing crystal form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid are presented in the following examples, but are not limited to them.

Option 1. Tablets.

Pharmaceutical compositions based on crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the form of tablets are presented in Table. 9.

The tablet composition contains 30 to 90 mg of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I. Excipients: croscarmellose sodium - 1.5-15 mg; magnesium stearate - 0-2 mg; stearic acid - 0-2 mg; microcrystalline cellulose - 25-80 mg; Povidone K-30 - 1-3 mg; calcium hydrophosphate - 0-100 mg; potato starch - 20-75 mg; - 1.5-15 mg, calcium stearate - 0-3 mg. The tablets may optionally be film-coated.

Additionally, the tablet may contain from 5 to 100 mg of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or a combination thereof.

During the compression process, it was observed that tablets containing form I are more resistant to crumbling and are compressed at a lower pressure than before recrystallization. Also, form I practically did not stick to the materials of the press, which indicates an improvement in its technological properties.

Option 2. Capsule

Pharmaceutical compositions based on 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I in the form of capsules are presented in Table 10.

The tablet composition contains 30 to 90 mg of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I. Excipients: colloidal silicon dioxide - 0.73-2.2 mg; potato starch - 11-33 mg; lactose monohydrate - 0-90 mg; magnesium stearate - 0.73-2.2 mg; microcrystalline cellulose - 0-64 mg; povidone K-25 - 0-10 mg; croscarmellose sodium - 0-4 mg.

Additionally, the capsule may contain from 5 to 100 mg of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or a combination thereof.

The capsule shell may contain substances commonly used for these purposes. Option 1: titanium dioxide - 1.3%; crimson dye - 0.0008%; dye azorubine - 0.307%; quinoline yellow dye - 0.4207%; gelatin - up to 100%. Option 2: titanium dioxide - 1%; iron dye yellow oxide - 1%, gelatin - up to 100%. Option 3. Powder.

Pharmaceutical compositions based on 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline Form I in powder form are shown in Table 11.

The powder composition contains 30 to 90 mg of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I. Excipients: mannitol - 0-4 mg; magnesium citrate - 100-400 mg; aspartame - 0-50 mg; citric acid - 25-50 mg; ascorbic acid - 0-400 mg; povidone K-30 - 5-15 mg; flavors - up to 200 mg.

The flavoring may include various substances, including, but not limited to: maltodextrin, acacia gum, α-pinene, β-pinene, limonene, γ-terpinene, linalool, neral, α-terpineol, geranial, etc.

Additionally, the powder may contain from 5 to 100 mg of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or combinations thereof.

Option 4. Liquid forms.

The composition in the form of an aqueous solution/syrup contains from 6 to 18 mg/ml of the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid. Excipients per 100 ml of liquid form: maltitol - 0-1000 mg; glycerol - 0-3000 mg; xanth gum - 0-300 mg; citric acid - 0-50 mg; sodium methyl parahydroxybenzoate - 0-100 mg; flavors - up to 200 mg; water - up to 100% (Table 12).

Additionally, the solution may contain from 1 to 20 mg/ml of umifenovir, favipiravir, remdesivir, paxlovide, molnupiravir, or combinations thereof.

Example 5 Method for Identification of Crystal Form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in solid pharmaceutical compositions

Tablets, capsules and powder obtained according to example 4 (without additional antiviral agent) were subjected to physicochemical analysis by X-ray phase analysis, infrared spectroscopy and differential scanning calorimetry to determine the possibility of identifying crystalline form I in a mixture of various excipients. It was found that when the content in the pharmaceutical composition of form I is more than 10% of the mass. it can be identified both by X-ray phase analysis and infrared spectroscopy, as well as by using these two methods together. This follows from the characteristic maxima in the diffraction pattern and one characteristic maximum in the IR spectrum of pharmaceutical compositions containing at least 10% of the mass. form I. The method of differential scanning calorimetry only indirectly indicates the content of form I and is auxiliary to the methods of X-ray phase analysis and infrared spectroscopy.

It was found that the method of X-ray phase analysis on a variety of compositions of pharmaceutical compositions containing crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, in an amount of at least 10% of the mass. regardless of the type of solid dosage form (tablet, capsule, powder) reveals four maxima at an angle 2θ of 19.05±0.2, 20.23±0.2, 21.26±0.2, 23.86±0 ,2, which correspond to Form I. With any composition of the pharmaceutical composition, any three maximums of these four remain.

As an example, in FIG. 6 shows a diffraction pattern of the contents of a capsule containing 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I and a number of excipients (Table 10, example 1). On FIG. Figure 6 clearly shows four maxima at an angle 2θ of 19.05±0.2, 20.23±0.2, 21.26±0.2, 23.86±0.2, which are the most intense and coincide with the maxima of form I in its purest form. The remaining maxima were not taken into account because of their shifts and because of the weak intensity.

By changing the compositions of pharmaceutical compositions, three of the four indicated maxima are always present on the diffraction pattern. It is possible to unambiguously identify the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in a solid pharmaceutical composition by X-ray phase analysis using at least three of the four maxima at an angle of 19.05 ± 0.2, 20.23±0.2, 21.26±0.2, 23.86±0.2 2θ degrees.

Thus, confirmation that the pharmaceutical composition contains 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystalline form I is the following sets of 2θ angles on the diffraction pattern:

19.05±0.2, 20.23±0.2, 21.26±0.2;

20.23±0.2, 21.26±0.2, 23.86±0.2;

19.05±0.2, 21.26±0.2, 23.86±0.2;

19.05±0.2, 20.23±0.2, 23.86±0.2.

It was found that the method of infrared spectroscopy on various formulations of pharmaceutical compositions containing crystalline form I 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid, in an amount of at least 10% of the mass. regardless of the type of solid dosage form (tablet, capsule, powder) reveals a characteristic absorption maximum at 637 cm ^-1 if form I in the composition is at least 10% by weight.

As an example, in FIG. 7 shows the FTIR diffuse reflectance spectrum of the contents of a capsule containing the crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid and a number of excipients (Table 10, example 1). On FIG. 7 clearly shows that the most intense maxima is the peak at 637 cm-1, which is also present in the IR spectrum of form I. The remaining maxima can vary greatly in the presence of various excipients.

Regardless of the composition of pharmaceutical forms, the IR spectrum always has a maximum at 637 cm ^-1 , which indicates that 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the composition is in crystalline form I, since this maximum in the IR spectrum was not found among analogues. Thus, 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid crystal form I in a solid pharmaceutical composition can be unambiguously identified by infrared spectroscopy if a maximum at 637 cm ^-1 is present in the IR spectrum.

The application of the differential scanning calorimetry method can complement the two methods listed above.

It was noted that the presence of excipients significantly reduces the melting point of crystalline form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid by 8°C from 201 to 193°C with a statistical error of ±3° C, since the excipients have a lower melting point.

As an example, in FIG. 8 shows the DSC curve of the contents of a capsule containing crystal form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid and a number of excipients (Table 10, example 1). From FIG. 8 shows that the DSC curve of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid against the background of excipients has a clear maximum at a melting temperature of 193°C. The excipients melt to the melting point of form I (broad maxima up to 100°C and a clear maximum at 150°C).

Thus, the method of differential scanning calorimetry makes it possible to determine the melting point of form I, which, due to the presence of substances with lower melting points in a mixture, decreases from 201 to 193°C.

Taken together, the analysis of pharmaceutical forms containing form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid by X-ray phase analysis, infrared spectroscopy and differential scanning calorimetry allows us to conclude that it is form I that should be determined. as part of the composition, you can use the following options for identification methods:

- X-ray phase analysis;

- infrared spectroscopy;

- X-ray phase analysis combined with infrared spectroscopy.

To these three options for identification methods, you can additionally apply the method of differential scanning calorimetry for a more complete analysis.

Claims (13)

1. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I, characterized by a diffraction pattern with a set of maxima at an angle of 2θ: 8.51±0.2, 8.76±0.2, 11.39± 0.2, 15.48±0.2, 17.03±0.2, 17.55±0.2, 17.77±0.2, 18.31±0.2, 19.05±0.2, 19.21±0.2, 19.73±0, 2, 20.23±0.2, 21.26±0.2, 21.78±0.2, 22.56±0.2, 23.86±0.2, 24.32±0.2, 25.50±0.2, 26.05±0.2, 27.07±0.2, 28.22±0.2, 29.13±0.2, 29.5±0.2, 30.11±0.2, 31.22±0.2, 31.76±0.2, 37.2±0.2, 38.14± 0.2, 40.25±0.2, 41.33±0.2, 41.94±0.2. 2. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, characterized by the diffraction pattern shown in FIG. 12. 3. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, having absorption maxima in the IR spectrum at 3240, 3147, 3097, 3003, 2965, 2853 , 2793, 2649, 1640, 1562, 1476, 1454, 1416, 1379, 1332, 1302, 1271, 1211, 1193, 1123, 1086, 1066, 1048, 1031, 933, 880, 8 36, 805, 761, 741, 708 , 666, 655 and 637 cm ^-1 . 4. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, characterized by the IR spectrum shown in FIG. 3. 5. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, in which the absorption maximum in the IR spectrum with maximum intensity is at 637 cm ^-1 . 6. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, which has a melting point of 201±3°C. 7. 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1, characterized by the DSC curve shown in FIG. 4. 8. The use of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1 as the active substance of a solid oral dosage form for the prevention and treatment of viral diseases. 9. The use of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 8, wherein 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl ]-butanoic acid in crystalline form I is used together with an antiviral agent selected from the group: umifenovir, favipiravir, remdesivir, paxlovid, molnupiravir. 10. A method for identifying 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in crystalline form I according to claim 1 in a solid dosage form for oral administration, characterized by the use of X-ray phase analysis, infrared spectroscopy and differential scanning calorimetry, in which the content of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the solid dosage form must be at least 10% by weight of the solid dosage form. 11. The identification method according to claim 10, in which, when using the X-ray phase analysis method to detect 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the form of crystalline form I, at least 3 any characteristic maxima at an angle of 2θ: 19.05±0.2, 20.23±0.2, 21.26±0.2, 23.86±0.2. 12. The method of identification according to claim 10, in which when using the method of infrared spectroscopy to detect 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid in the form of crystalline form I in the IR spectrum of diffuse reflection should there is an absorption maximum with a maximum intensity at 637 cm ^-1 . 13. The method of identification according to claim 10, in which, using the method of differential scanning calorimetry, the maximum melting point of form I of 4-[2-(1H-imidazol-4-yl)-ethylcarbamoyl]-butanoic acid is at a temperature of 193 ± 3 ° WITH.