Crystal form of indolepropionic acid-metformin salt as well as preparation method and application thereof

Abstract

The invention discloses a crystal form of indolepropionic acid-metformin salt as well as a preparation method and application thereof, and belongs to the technical field of chemical medicines and crystal form processes. An X-ray powder diffraction pattern of the compound has characteristic diffraction peaks at the following 2 theta angles: 8.8 degrees + / -0.2 degrees, 12.7 degrees + / -0.2 degrees, 14.1 degrees + / -0.2 degrees, 17.2 degrees + / -0.2 degrees, 18.0 degrees + / -0.2 degrees, 18.5 degrees + / -0.2 degrees and 19.6 degrees + / -0.2 degrees. The crystal form of the indolepropionic acid-metformin salt provided by the invention has good stability, has improved solubility and dissolution rate compared with indolepropionic acid, can solve the problem of lower solubility of indolepropionic acid, and combines metformin and indolepropionic acid which have a hypoglycemic effect, so that the stability of the indolepropionic acid-metformin salt is improved, and the stability of the indolepropionic acid-metformin salt is improved. The indolepropionic acid derivative is expected to promote the design and clinical application of indolepropionic acid preparations, possibly has a pharmacological synergistic effect in treatment of diabetes, and has the potential of developing drugs for treating diabetes.

Description

Technical Field

[0001] The present application relates to the field of chemical drugs and crystal process technology, and in particular to a crystal form of indolepropionic acid-metformin salt and a preparation method and use thereof. Background Art

[0002] Diabetes is a chronic metabolic disease, which is mainly divided into type 1 diabetes, type 2 diabetes and gestational diabetes. Its main characteristics are elevated blood sugar levels accompanied by disorders in fat and protein metabolism. The disease is difficult to cure and can easily cause complications in multiple organs (such as blood vessels, nerves, heart, kidneys, etc.).

[0003] Indole-3-propionic acid, chemical name is indole-3-propionic acid, molecular weight is 189.21, chemical structure is as follows:

[0004] .

[0005] Indolepropionic acid is a potential biomarker that is considered to be associated with the development of type 2 diabetes. It may prevent the occurrence of type 2 diabetes by protecting pancreatic beta cell function. Studies have shown that the intake of indolepropionic acid can significantly reduce fasting blood glucose levels and plasma insulin levels in rats, while improving insulin sensitivity and glucose metabolism. Therefore, indolepropionic acid is regarded as a potential candidate drug for the treatment of metabolic disorders caused by insulin resistance. In addition, indolepropionic acid also has potential application value in the treatment of various diseases such as cancer, colitis, tuberculosis and kidney disease. Although indolepropionic acid has diverse physiological activities, its solubility is low (intrinsic solubility is 0.35 g / L), and there are many challenges in its pharmacokinetic behavior in the body and formulation design, and the possible toxicity has brought many concerns. Summary of the invention

[0006] Based on this, the main purpose of this application is to provide a crystalline form of indolepropionic acid-metformin salt, which has improved solubility and dissolution, can solve the problem of low solubility of indolepropionic acid, and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0007] In the first aspect of the present application, a crystalline form of indolepropionic acid-metformin salt is provided, wherein the X-ray powder diffraction pattern thereof has characteristic diffraction peaks at the following 2θ angles: 8.8°±0.2°, 12.7°±0.2°, 14.1°±0.2°, 17.2°±0.2°, 18.0°±0.2°, 18.5°±0.2° and 19.6°±0.2°.

[0008] In some embodiments, the X-ray powder diffraction pattern thereof further has characteristic diffraction peaks at the following 2θ angles: one or more of 22.2°±0.2°, 24.3°±0.2°, 24.7°±0.2°, 27.7°±0.2° and 32.7°±0.2°.

[0009] In some embodiments, the X-ray powder diffraction pattern of the crystalline form is substantially as follows Figure 5 or Figure 6 or Figure 7 shown.

[0010] In some embodiments, the crystal data of the crystalline form of the indolepropionic acid-metformin salt include: monoclinic system; space group is P21 / n; the asymmetric unit contains an indolepropionic acid anion and a metformin cation, and the indolepropionic acid anion and the metformin cation are combined in a molar ratio of 1:1; unit cell parameters a = 10.517(4); b = 9.392(6); c = 17.126, α = 90.00°; β = 105.030°; γ = 90.00°; unit cell volume 1633.9 Å 3 ; The number of molecules in the unit cell Z = 4.

[0011] In some embodiments, the crystalline form of the indolepropionic acid-metformin salt satisfies one or more of the following conditions:

[0012] (1) The calculated crystal density of the crystalline form of the indolepropionic acid-metformin salt is 1.293 g / cm 3 ;

[0013] (2) Determined by differential scanning calorimetry, the crystalline form of the indolepropionic acid-metformin salt has a melting onset temperature of 181±5°C and a melting peak value of 183±5°C during heating at a heating rate of 10°C / min;

[0014] (3) As determined by a thermogravimetric analyzer, the crystalline form of the indolepropionic acid-metformin salt began to lose weight at 200±5°C when heated to 400°C at a rate of 20°C / min, and lost 80±1% of its weight at 395±5°C;

[0015] (4) The infrared absorption spectrum of the crystalline form of the indolepropionic acid-metformin salt is at least 3493 cm -1 、1557 cm -1 、1379 cm -1 and 1048 cm -1 There is an absorption peak at.

[0016] The second aspect of the present application provides a method for preparing a crystalline form of indolepropionic acid-metformin salt, comprising the following steps:

[0017] Indolepropionic acid, a first solvent and metformin free base are mixed for reaction, the solvent is removed, and the mixture is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0018] In some embodiments, the step of mixing indolepropionic acid, a first solvent and metformin free base for reaction comprises:

[0019] mixing the metformin free base with the first solvent to form a metformin free base solution, and mixing the metformin free base solution with the indolepropionic acid;

[0020] Alternatively, the metformin free base and the indolepropionic acid are added to the first solvent and mixed.

[0021] In some embodiments, the step of removing the solvent includes: at least one of solid-liquid separation, natural volatilization and rotary evaporation; optionally, the solid-liquid separation includes filtration and / or centrifugation.

[0022] In some embodiments, the mixing comprises stirring and / or grinding;

[0023] Optionally, the stirring conditions include: stirring temperature 10-40°C, stirring time 1-24h, stirring speed 50-1000 rpm;

[0024] Optionally, the grinding is ball milling, and the ball milling time is 30-90 min.

[0025] In some embodiments, the drying comprises at least one of natural drying, vacuum drying and freeze drying.

[0026] Optionally, the vacuum drying condition is: drying at 10-60° C. for 12-40 hours.

[0027] In some embodiments, the molar ratio of the indolepropionic acid to the metformin free base is 0.3-3:1; optionally 0.5-2:1, further optionally 0.9-1.1:1, and particularly optionally 1:1.

[0028] In some embodiments, the molar volume ratio of the metformin free base to the first solvent is 0.1 mol: (0.5-10) mL.

[0029] In some embodiments, the first solvent includes water and / or an organic solvent; the organic solvent includes at least one of an alcohol solvent, a ketone solvent, an ester solvent, a nitrile solvent, an ether solvent, an alkane, an aromatic hydrocarbon, and a halogenated hydrocarbon;

[0030] Optionally, the organic solvent includes at least one of methanol, ethanol, isopropanol, acetone, ethyl acetate, acetonitrile and dichloromethane.

[0031] Optionally, the organic solvent includes at least one of isopropanol, acetone, acetonitrile and dichloromethane.

[0032] In some embodiments, the preparation of metformin free base comprises the following steps:

[0033] Metformin hydrochloride, a base and a second solvent are mixed and reacted, and the solid and liquid are separated to obtain the metformin free base.

[0034] In some embodiments, the base comprises at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide;

[0035] And / or, the molar ratio of the metformin hydrochloride to the base is 1:0.5-2;

[0036] And / or, the second solvent includes water and / or an alcohol solvent; at least one of water, methanol and ethanol can be selected.

[0037] The third aspect of the present application provides a crystalline form of indolepropionic acid-metformin salt prepared by the preparation method described in the second aspect.

[0038] The fourth aspect of the present application provides a pharmaceutical composition, comprising the crystalline form of the indolepropionic acid-metformin salt described in the first or third aspect, and pharmaceutically acceptable excipients.

[0039] In some embodiments, the dosage form of the pharmaceutical composition includes tablets, capsules, pills, gels, emulsions or suspensions; tablets or capsules are optional.

[0040] The fifth aspect of the present application provides the use of the crystalline form of the indolepropionic acid-metformin salt described in the first or third aspect or the pharmaceutical composition described in the fourth aspect in the preparation of a drug for treating metabolic diseases of the endocrine system.

[0041] In some embodiments, the metabolic disease of the endocrine system comprises diabetes.

[0042] Beneficial effects of this application:

[0043] 1. The crystalline form of indolepropionic acid-metformin salt provided in the present application has good stability and improved solubility and dissolution compared with indolepropionic acid, which can solve the problem of low solubility of indolepropionic acid and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0044] 2. The crystalline form of indolepropionic acid-metformin salt provided in the present application combines metformin and indolepropionic acid, which have hypoglycemic effects, and has improved solubility and dissolution, and may have pharmacological synergistic effects in the treatment of diabetes, and has the potential to develop drugs for the treatment of diabetes. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art description are briefly introduced below. The drawings are only used to illustrate the preferred embodiments and are not considered to be limitations of the present application. Throughout the drawings, the same reference symbols are used to represent the same components, wherein the "salt" in the drawings refers to the "crystalline form of indolepropionic acid-metformin salt". In the drawings:

[0046] Figure 1 It is the crystal form of the indolepropionic acid-metformin salt obtained in Example 1 of the present application, the single crystal simulation, and the powder X-ray diffraction comparison spectrum of indolepropionic acid and metformin free base.

[0047] Figure 2 It is a Fourier transform infrared spectrum comparison chart of the crystalline form of the indolepropionic acid-metformin salt obtained in Example 1 of the present application, indolepropionic acid and metformin free base.

[0048] Figure 3 It is a comparative thermogravimetric analysis spectrum of the crystalline form of the indolepropionic acid-metformin salt, indolepropionic acid and metformin free base obtained in Example 1 of the present application.

[0049] Figure 4 It is a differential scanning calorimetry comparison chart of the crystalline form of the indolepropionic acid-metformin salt obtained in Example 1 of the present application, indolepropionic acid and metformin free base.

[0050] Figure 5 This is the powder X-ray diffraction pattern of the crystalline form of indolepropionic acid-metformin salt obtained in Example 4 of the present application.

[0051] Figure 6 This is the powder X-ray diffraction pattern of the crystalline form of the indolepropionic acid-metformin salt obtained in Example 5 of the present application.

[0052] Figure 7 This is the powder X-ray diffraction pattern of the crystalline form of the indolepropionic acid-metformin salt obtained in Example 6 of the present application.

[0053] Figure 8 It is a comparison diagram of the dissolution curves of the crystalline form of the indolepropionic acid-metformin salt prepared in Example 1 and indolepropionic acid in a pH 2.0 buffer solution.

[0054] Fig. 9It is a comparison diagram of the dissolution curves of the crystalline form of the indolepropionic acid-metformin salt prepared in Example 1 and indolepropionic acid in a pH 4.5 buffer solution.

[0055] Fig.10 It is a comparison diagram of the dissolution curves of the crystalline form of the indolepropionic acid-metformin salt prepared in Example 1 and indolepropionic acid in a pH 6.8 buffer solution.

[0056] Fig.11 The crystal form of the indolepropionic acid-metformin salt obtained in Example 1 of the present application was subjected to forced degradation conditions (60°C, 92.5% RH and light 5500 lx, 90 μW / cm 2 ) under comparative powder X-ray diffraction patterns.

[0057] Fig.12 It is the powder X-ray diffraction pattern of the sample obtained in Comparative Example 1 of the present application.

[0058] Fig.13 This is the powder X-ray diffraction pattern of the sample obtained in Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solution and advantages of this application clearer and to provide a more thorough and comprehensive understanding of the disclosed content of this application, the technical solution of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. The described embodiments are only part of the embodiments of this application, not all of them.

[0060] The implementation of the present application is described in detail below in conjunction with the accompanying drawings. This embodiment is implemented based on the technical solution of the present application, and a detailed implementation method and specific operation process are given, but the protection scope of the present application is not limited to the following embodiments.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0062] the term

[0063] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0064] In the present application, "plurality", "multiple" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" or "at least one" means one or greater than or equal to two.

[0065] In the present application, the terms "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0066] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0067] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0068] In this application, unless otherwise specified, the temperature parameter is allowed to be either a constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C and ±1°C are allowed.

[0069] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 2-5h means that the units of the left endpoint "2" and the right endpoint "5" are both h (hours).

[0070] The terms "indolepropionic acid and metformin salt", "crystalline form of indolepropionic acid-metformin salt" and "salt" in the present application are synonymous.

[0071] The "room temperature" in this application refers to the temperature range of 10-30°C.

[0072] In the first aspect of the present application, a crystalline form of indolepropionic acid-metformin salt is provided, wherein the X-ray powder diffraction pattern thereof has characteristic diffraction peaks at the following 2θ angles: 8.8°±0.2°, 12.7°±0.2°, 14.1°±0.2°, 17.2°±0.2°, 18.0°±0.2°, 18.5°±0.2° and 19.6°±0.2°.

[0073] Optionally, its X-ray powder diffraction pattern also has characteristic diffraction peaks at the following 2θ angles: one or more of 22.2°±0.2°, 24.3°±0.2°, 24.7°±0.2°, 27.7°±0.2° and 32.7°±0.2°.

[0074] The crystalline form of the indolepropionic acid-metformin salt of the present application has good stability and improved solubility and dissolution compared to indolepropionic acid, which can solve the problem of low solubility of indolepropionic acid and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0075] Optionally, the X-ray powder diffraction pattern of the crystalline form is substantially as follows Figure 5 or Figure 6 or Figure 7 shown.

[0076] Optionally, the X-ray powder diffraction pattern of the crystalline form has characteristic diffraction peaks at the following 2θ angles: 8.8°, 12.7°, 14.1°, 17.2°, 18.0°, 18.5°, 19.6°, 22.2°, 24.3°, 24.7°, 27.7° and 32.7°.

[0077] Optionally, the X-ray powder diffraction pattern of the crystalline form has characteristic diffraction peaks at the following 2θ angles: 8.9°, 12.8°, 14.3°, 17.4°, 18.2°, 18.7°, 19.8°, 22.4°, 24.5°, 24.9° and 32.9°.

[0078] Optionally, the X-ray powder diffraction pattern of the crystalline form has characteristic diffraction peaks at the following 2θ angles: 8.9°, 12.9°, 14.3°, 17.4°, 18.2°, 18.7°, 19.8°, 22.4°, 24.5°, 24.9° and 32.9°.

[0079] The crystal form of the indolepropionic acid-metformin salt of the present application is a single crystal structure, which has good stability. Specifically, the crystal data of the crystal form of the indolepropionic acid-metformin salt include: monoclinic system; space group is P21 / n; the asymmetric unit contains an indolepropionic acid anion and a metformin cation, and the indolepropionic acid anion and the metformin cation are combined in a molar ratio of 1:1; unit cell parameters a = 10.517 (4); b = 9.392 (6); c = 17.126, α = 90.00°; β = 105.030°; γ = 90.00°; unit cell volume 1633.9 Å 3 ; The number of molecules in the unit cell Z = 4.

[0080] Specifically, the calculated crystal density of the crystalline form of the indolepropionic acid-metformin salt is 1.293 g / cm 3 The infrared absorption spectrum of the crystalline form of the indolepropionic acid-metformin salt is at least 3493 cm -1 、1557 cm -1 、1379cm -1 and 1048 cm -1 There is an absorption peak at.

[0081] The crystalline form of the indolepropionic acid-metformin salt of the present application has good thermal stability. Specifically, as determined by differential scanning calorimetry, the crystalline form of the indolepropionic acid-metformin salt has a melting start temperature of 181±5°C and a melting peak value of 183±5°C during heating at a heating rate of 10°C / min; as determined by a thermogravimetric analyzer, the crystalline form of the indolepropionic acid-metformin salt begins to lose weight at 200±5°C during heating to 400°C at a rate of 20°C / min, and loses 80±1% of its weight at 395±5°C.

[0082] The second aspect of the present application provides a method for preparing a crystalline form of indolepropionic acid-metformin salt, comprising the following steps:

[0083] Indolepropionic acid, a first solvent and metformin free base are mixed for reaction, the solvent is removed, and the mixture is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0084] The crystalline form of the indolepropionic acid-metformin salt of the present application is obtained by a mixed reaction of indolepropionic acid and metformin free base, has a simple preparation process, combines metformin and indolepropionic acid, which have hypoglycemic effects, and has improved solubility and dissolution, which can solve the problem of low solubility of indolepropionic acid and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0085] In the present application, there is no specific requirement for the mixing order of indolepropionic acid, the first solvent and metformin free base, as long as the dissolution and dispersion of indolepropionic acid and metformin free base can be achieved. For example, the metformin free base can be mixed with the first solvent to form a metformin free base solution, and the metformin free base solution can be mixed with the indolepropionic acid; or the metformin free base and the indolepropionic acid can be added to the first solvent and mixed.

[0086] In the present application, the step of removing the solvent is to initially remove the solvent to facilitate the subsequent drying process, and the method of removing the solvent is not particularly limited. Specifically, the step of removing the solvent includes: at least one of solid-liquid separation, natural volatilization and rotary evaporation; wherein the solid-liquid separation may include filtration and / or centrifugation; the water bath temperature of the rotary evaporation is 30-50 ℃, for example, 30 ℃, 40 ℃, 50 ℃, etc.

[0087] In the present application, the purpose of drying is to remove moisture, and the drying method is not particularly limited, and natural drying, vacuum drying or freeze drying may be used; for example, the vacuum drying conditions may be: drying at 10-60°C (for example, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, etc.) for 12-40h (for example, 12h, 16h, 20h, 24h, 28h, 32h, 36h, 40h, etc.).

[0088] In the present application, there is no special requirement for the mixing conditions, as long as the dissolution and dispersion of indolepropionic acid and metformin free base can be achieved. Stirring, grinding and the like can be used to promote the mixing effect during the mixing process; wherein, the stirring conditions include: a stirring temperature of 10-40°C, for example, 10°C, 20°C, 30°C, 40°C, etc.; a stirring time of 1-24h, for example, 1h, 4h, 8h, 12h, 16h, 20h, 24h, etc.; a stirring speed of 50-1000 rpm, for example, 50rpm, 100rpm, 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, 800rpm, 1000rpm, etc.; the grinding is ball milling, and the ball milling time is 30-90min, for example, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc.

[0089] In the present application, the molar ratio of indolepropionic acid to metformin free base fluctuates within a certain range and has no effect on the quality of the crystalline form of indolepropionic acid-metformin salt. Specifically, the molar ratio of indolepropionic acid to metformin free base is 0.3-3:1; it can be 0.5-2:1, further can be 0.9-1.1:1, and can be 1:1, for example, 0.3:1, 0.5:1, 0.7:1, 0.9:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, etc.

[0090] In the present application, the function of the first solvent is to dissolve or disperse indolepropionic acid and metformin free base well, and the amount and type of the first solvent are not particularly limited.

[0091] Specifically, the molar volume ratio of the metformin free base to the first solvent is 0.1 mol: (0.5-10) mL, for example, 0.1 mol: 0.5 mL, 0.1 mol: 1 mL, 0.1 mol: 2 mL, 0.1 mol: 3 mL, 0.1 mol: 4 mL, 0.1 mol: 5 mL, 0.1 mol: 6 mL, 0.1 mol: 7 mL, 0.1 mol: 8 mL, 0.1 mol: 9 mL, 0.1 mol: 10 mL, etc.

[0092] Specifically, the first solvent includes water and / or an organic solvent; the organic solvent includes at least one of alcohol solvents, ketone solvents, ester solvents, nitrile solvents, ether solvents, alkanes, aromatic hydrocarbons and halogenated hydrocarbons; optionally, the organic solvent includes at least one of methanol, ethanol, isopropanol, acetone, ethyl acetate, acetonitrile and dichloromethane; further preferably, at least one of isopropanol, acetone, acetonitrile and dichloromethane.

[0093] In the present application, metformin free base can be a commercially available product or can be prepared by itself. For example, the preparation of metformin free base includes the following steps:

[0094] Metformin hydrochloride, a base and a second solvent are mixed and reacted, and the solid and liquid are separated to obtain the metformin free base.

[0095] It is understandable that after the solid-liquid separation step, steps such as redissolution, recrystallization and drying may also be included. In the process of mixing the metformin hydrochloride, the base and the second solvent for reaction, stirring may be used to improve the reaction uniformity and efficiency, and the stirring speed may be 50-1000rpm, for example, 50rpm, 100rpm, 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, 800rpm, 1000rpm, etc.

[0096] The metformin free base solution may be a solution obtained by redissolving the metformin free base, or a solution obtained by redissolving the solid obtained by redissolving, recrystallizing and drying the metformin free base in the first solvent.

[0097] In the present application, the role of the base is to react with metformin hydrochloride to obtain metformin free base, and the specific type is not particularly limited, and the amount can be adjusted according to actual needs. Specifically, the base includes at least one of sodium hydroxide, potassium hydroxide and calcium hydroxide; the molar ratio of the metformin hydrochloride to the base is 1:0.5-2, for example, 1:0.5, 1:1, 1:1.5, 1:2, etc.

[0098] In the present application, the second solvent is used to dissolve or disperse metformin hydrochloride and the base, and there is no special requirement for the specific type. Specifically, the second solvent includes water and / or an alcohol solvent; preferably at least one of water, methanol and ethanol.

[0099] According to the specific mixing and solvent removal processes, the preparation method of the present application can be divided into a reaction crystallization method, a solvent volatilization method, a suspension method and a solvent-assisted grinding method.

[0100] Wherein, the reaction crystallization method comprises the following steps:

[0101] Metformin free base is dispersed in a first solvent to form a metformin free base solution; indolepropionic acid is added to the metformin free base solution, mixed, filtered, and the solid is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0102] In the reaction crystallization method, a white solid is precipitated after the mixture is left to stand. The solvent is preferably an organic solvent that has a certain solubility for metformin free base, such as ketones and / or nitriles, and acetone is particularly preferred.

[0103] Wherein, the solvent volatilization method comprises the following steps:

[0104] Indolepropionic acid and metformin free base are added to a first solvent, mixed and reacted, the solvent is naturally evaporated, and dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0105] In the solvent evaporation method, the solvent is preferably a solvent with a certain solubility for indolepropionic acid and metformin free base, such as at least one of alcohols, ketones, esters, nitriles, ethers, alkanes, aromatic hydrocarbons and halogenated hydrocarbons, and at least one of methanol, ethanol, isopropanol and acetonitrile is particularly preferred; the time for naturally evaporating the solvent is 1-7 days, and it can be carried out at room temperature.

[0106] Wherein, the suspension method comprises the following steps:

[0107] Indolepropionic acid and metformin free base are added to the first solvent, mixed and reacted, filtered, and the solid is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0108] In the suspension method, the solvent is preferably a solvent having a certain solubility for indolepropionic acid and metformin free base, such as at least one of alcohols, ketones, esters, nitriles, ethers, alkanes, aromatic hydrocarbons and halogenated hydrocarbons, and particularly preferably at least one of methanol, ethanol, isopropanol and acetonitrile.

[0109] Wherein, solvent assisted grinding method comprises the following steps:

[0110] Indolepropionic acid and metformin free base are mixed, a first solvent is added, the mixture is ground, the solvent is removed, and the mixture is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

[0111] In the solvent-assisted grinding method, there is no special requirement for the solvent.

[0112] The third aspect of the present application provides a crystalline form of indolepropionic acid-metformin salt prepared by the preparation method described in the second aspect.

[0113] The crystalline form of the indolepropionic acid-metformin salt of the present application combines metformin and indolepropionic acid, which have hypoglycemic effects, and has improved solubility and dissolution, which can solve the problem of low solubility of indolepropionic acid and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0114] The fourth aspect of the present application provides a pharmaceutical composition, comprising the crystalline form of the indolepropionic acid-metformin salt described in the first or third aspect, and pharmaceutically acceptable excipients.

[0115] The pharmaceutical composition of the present application includes a crystalline form of indolepropionic acid-metformin salt, which can solve the problem of low solubility of indolepropionic acid and is expected to promote the design and clinical application of indolepropionic acid preparations.

[0116] In the present application, the dosage form of the pharmaceutical composition is not particularly limited and may include tablets, capsules, pills, gels, emulsions or suspensions; considering medication compliance, etc., tablets or capsules are preferred.

[0117] The fifth aspect of the present application provides the use of the crystalline form of the indolepropionic acid-metformin salt described in the first or third aspect or the pharmaceutical composition described in the fourth aspect in the preparation of a drug for treating metabolic diseases of the endocrine system.

[0118] The crystalline form or pharmaceutical composition of the indolepropionic acid-metformin salt of the present application has good stability and improved solubility and dissolution rate compared with indolepropionic acid, which can solve the problem of low solubility of indolepropionic acid, and combines metformin and indolepropionic acid with hypoglycemic effects, which may have pharmacological synergistic effects in the treatment of diabetes and has the potential to develop drugs for the treatment of diabetes.

[0119] Specifically, the metabolic disease of the endocrine system includes diabetes.

[0120] Unless otherwise specified, the raw materials used in the following experiments can be purchased from the market.

[0121] The information of the instruments and performance test methods used in the embodiments and comparative examples are as follows:

[0122] The X-ray powder diffraction pattern was obtained using a Shimadzu XRD-6000 X-ray powder diffractometer, which uses Cu-Kα radiation (λ = 1.5418 Å); radiation scanning range: 3 - 40°; scanning speed: 2 ° / min, and the analysis software used is MDI Jade 6.0.

[0123] The single crystal data were obtained using a Bruker D8 Advance single crystal X-ray diffractometer with a graphite monochromator and Mo-Kα radiation (λ = 0.71073 Å); the test temperature was 170 K; the SAINT-5.0 and SHELXTL-2017 programs were used to complete the data restoration and structural analysis of the single crystal structure, and the absorption correction was completed by the SADABS program.

[0124] Differential scanning calorimetry was performed using a Netzsch DSC 3500 instrument with a heating rate of 10 °C / min.

[0125] Thermogravimetric analysis was performed using a Netzsch TG 209F3 instrument with a heating rate of 20 °C / min.

[0126] Fourier transform infrared spectrometer was Nicolet iS50, scanning range: 4000-400 cm -1 , resolution 4 cm -1 .

[0127] The HPLC data were determined using a Shimadzu LC-20 HPLC. The chromatographic column was a C18 column (4.6 mm × 150 mm, 5 μm); -1 Sodium heptane sulfonate solution (pH 2.8) was used as mobile phase A, and acetonitrile was used as mobile phase B. Gradient elution was performed according to Table 1. The flow rate was 1.0 mL / min. The column temperature was 40 °C. The detection wavelength was 230 nm. The injection volume was 10 μL.

[0128] Table 1 Elution gradient

[0129]

[0130] The following are specific embodiments.

[0131] Preparation Example 1

[0132] Preparation of metformin free base solution:

[0133] 1) Add metformin hydrochloride (10 mmol) and sodium hydroxide (10 mmol) into a conical flask, add 100 mL of anhydrous ethanol, stir at 500 rpm for 1 hour at room temperature, filter to remove the white solid, and rotary evaporate the solution in a 40 °C water bath to obtain a white powder, i.e., crude metformin free base;

[0134] 2) Dissolve the crude metformin free base obtained in step 1) in 100 mL of acetone and stir for 10 min. Filter to remove the white insoluble matter to obtain a colorless transparent solution, which is the metformin free base solution.

[0135] Preparation Example 2

[0136] The metformin free base solution prepared in Preparation Example 1 was subjected to rotary evaporation to obtain a white powder, namely, metformin free base.

[0137] Example 1

[0138] Indolepropionic acid (10 mmol) was added to the metformin free base solution (10 mmol metformin free base) obtained in step 2) of Preparation Example 1. After standing for a while, a white solid precipitated. The filtrate was filtered and vacuum dried at room temperature for 24 hours to obtain a white powder, i.e., a crystalline form of indolepropionic acid-metformin salt.

[0139] The crystal form of the obtained indolepropionic acid-metformin salt was characterized by powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The crystal forms of the indolepropionic acid-metformin salt were compared with those of indolepropionic acid and metformin free base. Figure 1-Figure 4 As shown, the crystalline form of indolepropionic acid-metformin salt has characteristic diffraction peaks at 8.8°, 12.7°, 14.1°, 17.2°, 18.0°, 18.5°, 19.6°, 22.2°, 24.3°, 24.7°, 27.7° and 32.7°.

[0140] Example 2

[0141] About 100 mg of the crystalline form of indolepropionic acid-metformin salt of Example 1 was added to 0.4 mL of water and completely dissolved after heating at 40° C. Then, the crystalline form was placed in a refrigerator at 4° C. and transparent block-shaped single crystals were obtained after about 1 week.

[0142] Single crystal X-ray diffraction analysis showed that the obtained bulk single crystal was monoclinic with space group P21 / n. a = 10.517(4), b = 9.392(6), c = 17.126, α = 90.00°, β = 105.030°, γ = 90.00°, unit cell volume 1633.9 Å 3, the number of molecules in the unit cell is Z = 4, and the calculated crystal density is 1.293 g / cm 3 .

[0143] The powder X-ray diffraction results obtained from the single crystal simulation of Example 2 are basically consistent with the powder X-ray diffraction pattern in Example 1, verifying that the crystal and the crystal form of the indolepropionic acid-metformin salt obtained in Example 1 are the same crystal form.

[0144] Example 3

[0145] Metformin free base (Preparation Example 2, 0.1 mmol) and indolepropionic acid (0.1 mmol) were added to 4 mL of acetonitrile, stirred at 1000 rpm at room temperature for 1 hour, and the solvent was evaporated at room temperature after complete dissolution. Block single crystals were obtained after 3-4 days. The powder X-ray diffraction results obtained by single crystal simulation were basically consistent with the powder X-ray diffraction pattern in Example 1, verifying that the crystal and the crystal form of indolepropionic acid-metformin salt obtained in Example 1 were the same crystal form.

[0146] Example 4

[0147] Metformin free base (Preparation Example 2, 0.1 mmol) and indole propionic acid (0.1 mmol) were added to 4 mL of isopropanol and stirred at 800 rpm for 1 hour at room temperature. After complete dissolution, the solvent was evaporated at room temperature to obtain a white powder after 7 days. After vacuum drying at 60 °C for 24 hours, the crystal form of indole propionic acid-metformin salt was obtained. Its powder X-ray diffraction pattern is as follows: Figure 5 As shown, there are characteristic diffraction peaks at 8.9°, 12.8°, 14.3°, 17.4°, 18.2°, 18.7°, 19.8°, 22.4°, 24.5°, 24.9° and 32.9°, which are basically consistent with the powder X-ray diffraction pattern in Example 1, confirming that the same crystal form as in Example 1 is obtained.

[0148] Example 5

[0149] Metformin free base (Preparation Example 2, 0.1 mmol) and indolepropionic acid (0.1 mmol) were added to 4 mL of acetone, stirred at 200 rpm for 12 hours at room temperature, filtered, and the filtrate was vacuum dried at 40 °C for 24 hours to obtain a white powder, i.e., the crystalline form of indolepropionic acid-metformin salt. Its powder X-ray diffraction pattern is as follows: Figure 6 As shown, there are characteristic diffraction peaks at 8.9°, 12.9°, 14.3°, 17.4°, 18.2°, 18.7°, 19.8°, 22.4°, 24.5°, 24.9° and 32.9°, which are basically consistent with the powder X-ray diffraction pattern in Example 1, confirming that the same crystal form as in Example 1 is obtained.

[0150] Example 6

[0151] Metformin free base (Preparation Example 2, 0.1 mmol) and indolepropionic acid (0.2 mmol) were added to 4 mL of dichloromethane, stirred at 50 rpm for 24 hours at room temperature, filtered, and the filtrate was vacuum dried at 20 °C for 24 hours to obtain a white powder, i.e., the crystalline form of indolepropionic acid-metformin salt. Its powder X-ray diffraction pattern is as follows: Figure 7 As shown, there are characteristic diffraction peaks at 8.9°, 12.8°, 14.3°, 17.3°, 18.1°, 18.6°, 19.8°, 22.3°, 24.5°, 24.9° and 32.8°, which are basically consistent with the powder X-ray diffraction pattern in Example 1, confirming that the same crystal form as in Example 1 is obtained.

[0152] Test Example 1

[0153] Comparison of the solubility of the crystalline form of indolepropionic acid-metformin salt and indolepropionic acid monomer

[0154] An excess of the crystal form of indolepropionic acid-metformin salt prepared in Example 1 and indolepropionic acid monomer were weighed and placed in a pH 2.0, 4.5, and 6.8 buffer. The mixture was shaken at 250 rpm in a constant temperature incubator at 25°C for 24 hours, centrifuged after standing for 24 hours, and the supernatant was taken. The supernatant was diluted 100 times with 20% acetonitrile and the concentration of indolepropionic acid in the solution was determined by high performance liquid chromatography to obtain the crystal form of indolepropionic acid-metformin salt and the equilibrium solubility of indolepropionic acid in the monomer.

[0155] The experimental results are shown in Table 2:

[0156] Table 2 Crystal forms of indolepropionic acid-metformin salt and indolepropionic acid monomer in different pH buffer solutions

[0157] Equilibrium Solubility Comparison

[0158]

[0159] As can be seen from Table 2, in pH 4.5 and pH 6.8 buffers, the equilibrium solubility of the crystalline form of indolepropionic acid-metformin salt is increased to 204 and 35 times, respectively, compared with the indolepropionic acid monomer. The higher equilibrium solubility can ensure that the drug maintains a higher supersaturation state in the digestive tract, so that the drug is quickly absorbed through the inner wall of the digestive tract into the blood circulation, increasing the blood drug concentration, and thus helping to improve the bioavailability and ensure the efficacy of the drug.

[0160] Test Example 2

[0161] Comparison of the dissolution rates of the crystalline forms of indolepropionic acid-metformin salt and indolepropionic acid monomer

[0162] After the indolepropionic acid monomer and the crystal form of indolepropionic acid-metformin salt prepared in Example 1 were sieved through a 100-mesh sieve, the excess indolepropionic acid and the crystal form of indolepropionic acid-metformin salt with the corresponding content were weighed, and 10 mL of pH 2.0, pH 4.5 and pH 6.8 buffer solutions were added. The stirring speed was 150 rpm and the solution temperature was 37 °C. 300 μL of solution was taken at 1, 3, 5, 10, 15, 20, 30 and 60 minutes, filtered with a 0.22 μm filter membrane, diluted 100 times with 20% acetonitrile, and the concentration of indolepropionic acid in the solution at each time point was determined by high performance liquid chromatography, and repeated three times. Finally, the dissolution curves of the indolepropionic acid monomer and the crystal form of indolepropionic acid-metformin salt in pH 2.0, pH 4.5 and pH 6.8 buffer solutions were obtained, and the results were as follows: Figure 8 , Fig. 9 and Fig.10 shown.

[0163] from Figure 8-Figure 10 The results show that the apparent solubility of the indolepropionic acid-metformin salt crystal form is higher, and at the same time, it shows a faster dissolution rate, especially in the buffer solution of pH 4.5 and 6.8, the dissolution advantage of the indolepropionic acid-metformin salt crystal form is extremely significant, which is consistent with the solubility results of Test Example 1. The higher dissolution rate can make the drug dissolve quickly in the digestive tract, reach the supersaturated state faster, and reduce the time to peak blood drug concentration (t max ), higher apparent solubility can also allow the drug to be quickly absorbed through the inner wall of the digestive tract into the blood circulation, increasing the peak blood drug concentration (c max ), and may increase bioavailability.

[0164] Test Example 3

[0165] Evaluation of the Crystal Stability of Indolepropionic Acid-Metformin Salt

[0166] The crystals of indolepropionic acid-metformin salt prepared in Example 1 were passed through a 100-mesh sieve and sieved under high temperature (60 °C), high humidity (92.5% RH) and light (5500 lx, 90 μW / cm 2 ) conditions and placed for 10 days. The crystal forms of the undegraded indolepropionic acid-metformin salt and the salts under various degradation conditions were analyzed by powder X-ray diffraction analysis and high performance liquid chromatography for related substances to evaluate the crystal form stability and chemical stability of the indolepropionic acid-metformin salt. The results are shown in Tables 3 and Fig.11 shown.

[0167] Table 3 Chemical stability of the crystalline form of indolepropionic acid-metformin salt

[0168]

[0169] Depend on Fig.11 It can be seen that the characteristic diffraction peaks shown by the crystal forms of indolepropionic acid-metformin salt under undegraded and various degradation conditions are relatively consistent, indicating that the crystal forms of indolepropionic acid-metformin salt have good stability under the three degradation conditions; as shown in Table 3, the amount of impurities detected in the crystal forms of indolepropionic acid-metformin salt under high temperature and high humidity conditions did not show significant differences, and no new degradation impurities were generated, showing good chemical stability; under light conditions, a small amount of new impurity Imp1 was generated, indicating that the crystal forms of indolepropionic acid-metformin salt need to be stored away from light.

[0170] Comparative Example 1

[0171] Metformin hydrochloride (0.1 mmol) and indolepropionic acid (0.1 mmol) were added to 4 mL of isopropanol and stirred at 800 rpm for 1 hour at room temperature. After complete dissolution, the solvent was evaporated at room temperature to obtain a white powder after 7 days. The powder X-ray diffraction pattern of the sample after vacuum drying at 60 °C for 24 hours is as follows: Fig.12 As shown, Figure 5 By comparison, the characteristic diffraction peaks of the crystalline form of indolepropionic acid-metformin salt did not appear, and the crystalline form of indolepropionic acid-metformin salt could not be obtained.

[0172] Comparative Example 2

[0173] Metformin hydrochloride (0.1 mmol) and indolepropionic acid (0.1 mmol) were added to 4 mL of acetone, stirred at 200 rpm for 12 hours at room temperature, filtered, and the filtrate was vacuum dried at 40 °C for 24 hours to obtain a white powder. Its powder X-ray diffraction pattern is as follows: Fig.13 As shown, Figure 5 By comparison, the characteristic diffraction peaks of the crystalline form of indolepropionic acid-metformin salt did not appear, and the crystalline form of indolepropionic acid-metformin salt could not be obtained.

[0174] It can be seen from Comparative Examples 1 and 2 that the crystalline form of indolepropionic acid-metformin salt was not prepared by using metformin hydrochloride and adopting the solvent evaporation method or the suspension method.

[0175] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0176] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A crystalline form of indolepropionic acid-metformin salt, characterized in that: Its X-ray powder diffraction pattern has characteristic diffraction peaks at the following 2θ angles: 8.8°±0.2°, 12.7°±0.2°, 14.1°±0.2°, 17.2°±0.2°, 18.0°±0.2°, 18.5°±0.2° and 19.6°±0.2°.

2. The crystalline form of indolepropionic acid-metformin salt according to claim 1, characterized in that: Its X-ray powder diffraction pattern also has characteristic diffraction peaks at the following 2θ angles: one or more of 22.2°±0.2°, 24.3°±0.2°, 24.7°±0.2°, 27.7°±0.2° and 32.7°±0.2°.

3. The crystalline form of indolepropionic acid-metformin salt according to claim 1, characterized in that: Its X-ray powder diffraction pattern is basically as shown in Figure 5 or Figure 6 or Figure 7.

4. The crystalline form of indolepropionic acid-metformin salt according to claim 1 or 2, characterized in that: The crystal data of the crystalline form of the indolepropionic acid-metformin salt include: monoclinic system; space group is P21 / n; the asymmetric unit contains an indolepropionic acid anion and a metformin cation, and the indolepropionic acid anion and the metformin cation are combined in a molar ratio of 1:1; unit cell parameters a = 10.517(4); b = 9.392(6); c = 17.126, α = 90.00°; β = 105.030°; γ = 90.00°; unit cell volume 1633.9 Å 3 ; The number of molecules in the unit cell Z = 4.

5. The crystalline form of indolepropionic acid-metformin salt according to claim 4, characterized in that: The crystalline form of the indolepropionic acid-metformin salt satisfies one or more of the following conditions: (1) The calculated crystal density of the crystalline form of the indolepropionic acid-metformin salt is 1.293 g / cm 3 ; (2) Determined by differential scanning calorimetry, the crystalline form of the indolepropionic acid-metformin salt has a melting onset temperature of 181±5°C and a melting peak value of 183±5°C during heating at a heating rate of 10°C / min; (3) As determined by a thermogravimetric analyzer, the crystalline form of the indolepropionic acid-metformin salt began to lose weight at 200±5°C when heated to 400°C at a rate of 20°C / min, and lost 80±1% of its weight at 395±5°C; (4) The infrared absorption spectrum of the crystalline form of the indolepropionic acid-metformin salt is at least 3493 cm -1 、1557 cm -1 、1379 cm -1 and 1048 cm -1 There is an absorption peak at.

6. A method for preparing a crystalline form of indolepropionic acid-metformin salt, characterized in that: The steps include: Indolepropionic acid, a first solvent and metformin free base are mixed and reacted, the solvent is removed, and the mixture is dried to prepare the crystalline form of the indolepropionic acid-metformin salt.

7. The preparation method according to claim 6, characterized in that: One or more of the following conditions are met: (1) The step of mixing indolepropionic acid, a first solvent and metformin free base for reaction comprises: mixing the metformin free base with the first solvent to form a metformin free base solution, and mixing the metformin free base solution with the indolepropionic acid; or adding the metformin free base and the indolepropionic acid into the first solvent and mixing; (2) The step of removing the solvent comprises: at least one of solid-liquid separation, natural volatilization and rotary evaporation; (3) The mixing includes stirring and / or grinding; optionally, the stirring conditions include: stirring temperature 10-40 °C, stirring time 1-24h, stirring speed 50-1000 rpm; optionally, the grinding is ball milling, and the ball milling time is 30-90min; (4) The drying comprises at least one of natural drying, vacuum drying and freeze drying; optionally, the vacuum drying condition is: drying at 10-60°C for 12-40h; (5) The molar ratio of the indolepropionic acid to the metformin free base is 0.3-3:1; optionally 0.5-2:1, further optionally 0.9-1.1:1, and particularly optionally 1:1; (6) The molar volume ratio of the metformin free base to the first solvent is 0.1 mol: (0.5-10) mL; (7) The first solvent includes water and / or an organic solvent; the organic solvent includes at least one of an alcohol solvent, a ketone solvent, an ester solvent, a nitrile solvent, an ether solvent, an alkane, an aromatic hydrocarbon and a halogenated hydrocarbon; optionally, the organic solvent includes at least one of methanol, ethanol, isopropanol, acetone, ethyl acetate, acetonitrile and dichloromethane; more preferably, at least one of isopropanol, acetone, acetonitrile and dichloromethane; (8) The preparation of metformin free base comprises the following steps: Metformin hydrochloride, a base and a second solvent are mixed for reaction, and the solid-liquid separation is performed to obtain the metformin free base; optionally, the base includes at least one of sodium hydroxide, potassium hydroxide and calcium hydroxide; optionally, the molar ratio of the metformin hydrochloride to the base is 1:0.5-2; optionally, the second solvent includes water and / or an alcohol solvent, and further at least one of water, methanol and ethanol can be selected.

8. The crystalline form of indolepropionic acid-metformin salt prepared by the preparation method according to claim 6 or 7.

9. A pharmaceutical composition comprising the crystalline form of indolepropionic acid-metformin salt according to any one of 1 to 5 or claim 8, and a pharmaceutically acceptable excipient; Optionally, the dosage form of the pharmaceutical composition includes tablets, capsules, pills, gels, emulsions or suspensions; tablets or capsules may be selected.

10. Use of the crystalline form of indolepropionic acid-metformin salt according to any one of claims 1 to 5 or claim 8 or the pharmaceutical composition according to claim 8 in the preparation of a medicament for treating metabolic diseases of the endocrine system; Optionally, the metabolic disease of the endocrine system includes diabetes.

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