Chrysin polymorphic substance and preparation method thereof

Abstract

The invention discloses a polymorphic substance of chrysin and a preparation method of the polymorphic substance, the polymorphic substance is a metastable crystal form, the crystal form of the polymorphic substance is marked as a beta crystal form, an X-ray powder diffraction pattern of the polymorphic substance has characteristic peaks when 2 theta values are 7.03, 8.38, 9.16, 11.92, 12.52, 13.82, 15.68, 19.81, 22.38, 24.83 and 26.64, and the 2 theta error range is + / -0.2 degrees. The problem that existing chrysin is poor in solubility in water is solved, the novel crystal form of chrysin is provided, the solubility of chrysin can be remarkably improved, preparation conditions are simple, easy to control, safe and environmentally friendly, and the crystal form is suitable for large-scale process production.

Description

Technical Field

[0001] The invention relates to a chrysin crystal form, and in particular to a chrysin polymorph and a preparation method thereof. Background Art

[0002] In the pharmaceutical field, 90% of active pharmaceutical ingredients are small organic molecules, of which more than 80% have polymorphism. Polymorphism refers to the phenomenon that substances with the same chemical composition can crystallize into two or more crystals with different structures under different physical and chemical conditions. Active pharmaceutical ingredients in different crystal forms often exhibit different physical and chemical properties, such as solubility, dissolution rate, melting point, hygroscopicity, compressibility, etc., and these physical and chemical properties will have a certain impact on the application of the compound.

[0003] Metastable crystalline forms are usually ideal for commercially available drugs due to their excellent solubility, dissolution rate, and bioavailability. However, the harsh preparation conditions and the instability of polymorphs during processing limit the application of metastable crystalline forms. Therefore, it is crucial to develop a method to effectively regulate and stabilize drug polymorphs.

[0004] Chrysin is a flavonoid compound with a wide range of pharmacological activities. Its structure is shown in Formula I. Its melting point is 285°C. It is soluble in alkali hydroxide solution, slightly soluble in ether, ethanol and chloroform, and insoluble in water. Chrysin has a wide range of pharmacological and physiological activities such as anti-oxidation, anti-tumor, anti-cancer, anti-virus, anti-hypertension, anti-diabetes, anti-bacterial, and anti-allergic. Moreover, this type of compound is widely distributed in plants and has relatively low toxicity. Therefore, it is a very important resource in the development and research of new drugs.

[0005]

[0006] Studies have shown that the compound with the highest anti-tumor activity among natural flavonoids is 5,7-dihydroxyflavone, also known as chrysin. Since the 1990s, people have begun to study the pharmacology of chrysin. In recent years, there have been increasing reports on research on chrysin and its derivatives at home and abroad, and some compounds with good activity have been obtained, and their clinical application prospects have gradually emerged, but there has been no such drug research and development on the market. This may be due to its poor solubility, and chrysin is insoluble in water, making it difficult to apply in the pharmaceutical field. For the traditional Chinese medicine chrysin, the higher the drug solubility and the faster the dissolution rate, the higher its absorption rate and bioavailability (see Chrysin induces brown fat-like phenotype and enhances lipid metabolism in 3T3-L1 adipocytes, Nutrition 32 (2011) 1002-1010; Beneficial effects of chrysin on the reproductive system of adult male rats, Andrologia 44 (2012) 181-186; Chrysin alleviates testicular dysfunction in adjuvant arthritic rats via suppression of inflammation and apoptosis: comparison with celecoxib, Toxic. App. Pharma. 279 (2014) 129-140; Constituents of Propolis: Chrysin caffeic acid p-coumaric acid and ferulicacid induce prodh / pox-dependent apoptosis in human tongue squamous cell carcinoma cell(CAL-27), Frontiers. Pharmacol. 9(2018)336).

[0007] Therefore, it is necessary to develop polymorphs of the compound of formula I, and it is crucial that the preparation method is simple, has high solubility, and can be scalable.

[0008] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0009] The purpose of the present invention is to provide a polymorph of chrysin and a preparation method thereof, which solves the problem of poor solubility of existing chrysin in water, provides a new crystal form of chrysin, can significantly improve the solubility of chrysin, and the preparation conditions are simple, easy to control, safe and environmentally friendly, and suitable for large-scale process production.

[0010] In order to achieve the above object, the present invention provides a polymorph of chrysin, which is a metastable crystal form, and its crystal form is recorded as β crystal form. Its X-ray powder diffraction spectrum has characteristic peaks at 2θ values ​​of 7.03, 8.38, 9.16, 11.92, 12.52, 13.82, 15.68, 19.81, 22.38, 24.83, and 26.64, and the 2θ error range is ±0.2°.

[0011] Preferably, the X-ray powder diffraction pattern of the polymorph is substantially as follows Figure 6 shown.

[0012] Preferably, the X-ray powder diffraction pattern of a single crystal of the polymorph is substantially as follows Figure 7 shown.

[0013] Preferably, the polymorph has endothermic peaks in the ranges of 152°C to 162°C and 287°C to 299°C.

[0014] Preferably, the DSC diagram of the polymorph is substantially as follows Fig. 9 shown.

[0015] Preferably, the melting point of the polymorph is 157±0.3°C.

[0016] Preferably, the TG diagram of the polymorph is substantially as follows Fig.11 shown.

[0017] Another object of the present invention is to provide a method for preparing the polymorph, which comprises the following steps:

[0018] (1) providing a first mixed solution, wherein the first mixed solution is obtained by dissolving an additive and an organic solvent;

[0019] (2) adding an excess amount of existing chrysin to the first mixed solution obtained in step (1) to completely precipitate the additive;

[0020] (3) filtering the mixed solution obtained in step (2);

[0021] (4) The filtrate obtained in step (3) is allowed to stand to evaporate the solvent, and solid is allowed to precipitate to obtain β-crystal chrysin.

[0022] Among them, the existing chrysin crystal form is defined as an α crystal form, and its X-ray powder diffraction spectrum has characteristic peaks at 2θ values ​​of 7.51, 12.71, 14.96, 17.82, 20.76, 22.38, 25.04, and 27.86, and the 2θ error range is ±0.2°; the additive is selected from 4-dimethylaminopyridine; the dosage ratio of the additive in the organic solvent is not less than 0.002g:3mL; the organic solvent is selected from any one of acetone, dichloromethane, chloroform, 1,2-dichloroethane, and ethyl acetate.

[0023] The inventors of the present invention have found that when 4-dimethylaminopyridine is used as an additive, 4-dimethylaminopyridine can form intermolecular hydrogen bonds with chrysin, thereby protecting the hydroxyl functional groups of chrysin. The OH in one molecule of chrysin forms a hydrogen bond with the O in the OH protected by 4-dimethylaminopyridine in another molecule of chrysin, thereby rearranging the space and forcing the chrysin molecules to appear in a new crystal form.

[0024] Preferably, in step (2), an excess amount of existing chrysin is added to the first mixed solution, and the mixture is reacted in a constant temperature shaker at 35° C. and 220 rpm.

[0025] Preferably, the reaction time is 6 hours.

[0026] The polymorph of chrysin and the preparation method thereof of the present invention solve the problem of poor solubility of existing chrysin in water and have the following advantages:

[0027] The present invention induces the formation of polymorphs of chrysin in the presence of the additive 4-dimethylaminopyridine, 4-dimethylaminopyridine forms intermolecular hydrogen bonds with chrysin, protects the hydroxyl functional group of chrysin, OH in one molecule of chrysin forms hydrogen bonds with O in OH protected by 4-dimethylaminopyridine in another molecule of chrysin, and rearranges the space, thereby obtaining a metastable crystalline form of chrysin, and the crystalline form thereof is defined as a β-crystalline form. Compared with the existing chrysin crystalline form (defined as an α-crystalline form), the β-crystalline form obtained by the present invention has significantly improved solubility in water, providing certain medical value and commercial prospects for chrysin.

[0028] In addition, the method of the present invention has the advantages of simple preparation conditions, easy control, safety and environmental protection, and is suitable for large-scale process production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a single crystal structure diagram of the existing chrysin α crystal form.

[0030] Figure 2 This is a single crystal structure diagram of the β-crystal form of chrysin of the present invention.

[0031] Figure 3The PXRD diagrams of the products obtained under different additive dosages of the present invention are shown in FIG.

[0032] Figure 4 The PXRD patterns of the products obtained in different organic solvents of the present invention are shown in FIG.

[0033] Figure 5 This is the PXRD diagram of the α-crystal form of the existing chrysin raw material used in the present invention.

[0034] Figure 6 This is the PXRD pattern of the β-crystal of chrysin prepared in Experimental Example 2 of the present invention.

[0035] Figure 7 This is the single crystal PXRD pattern of the β-crystal form of chrysin prepared in Experimental Example 2 of the present invention.

[0036] Figure 8 This is the DSC diagram of the α-crystal form of the existing chrysin raw material used in the present invention.

[0037] Fig. 9 This is the DSC graph of the β-crystal of chrysin prepared in Experimental Example 2 of the present invention.

[0038] Fig.10 This is the TG diagram of the α-crystal of the existing chrysin raw material used in the present invention.

[0039] Fig.11 This is the TG graph of the β-crystal of chrysin prepared in Experimental Example 2 of the present invention.

[0040] Fig.12 It is a comparison chart of the dissolution behavior curves of the existing chrysin raw material α-crystal and the chrysin β-crystal prepared in Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that if no specific conditions are specified in the examples, the experiments were carried out according to conventional conditions or conditions recommended by the manufacturer. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0043] In the present invention, all features defined in the form of numerical ranges or percentage ranges, such as values, quantities, contents and concentrations, are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0044] The features mentioned in the present invention can be combined arbitrarily, as long as there is no contradiction in the combination of these features, all possible combinations should be considered as the scope of this specification. Each feature disclosed in the specification can be replaced by any alternative feature that can provide the same, equal or similar purpose. Therefore, unless otherwise specified, the disclosed features are only general examples of equal or similar features.

[0045] The inventors of the present invention discovered a new crystal form of chrysin through catalyst-induced crystallization, and defined the new crystal form as β-crystal form. The existing chrysin crystal form is defined as α-crystal form. Their single crystal structures are shown in Figure 2 and Figure 1 The solubility of the β-crystal obtained by the present invention in water is significantly improved. Therefore, the present invention provides a polymorph of chrysin and a preparation method thereof. In the solvent, the presence of the additive provides another site for the arrangement of crystal nuclei for chrysin, and the excess chrysin in the solvent will force the additive to precipitate completely, thereby avoiding the influence of impurities on the crystallization process. After filtration, a clear solution is obtained, and the β-crystal of chrysin, which is a dominant metastable crystal form of chrysin, is obtained by crystallization in the solution, which provides a valuable application prospect for the development of chrysin as a drug.

[0046] The following is a detailed description of a polymorph of chrysin and a preparation method thereof provided by the present invention through experimental examples.

[0047] Experimental Example 1 Screening of Preparation Conditions for β-Crystalline Chrysin

[0048] 1. Screening of additive dosage

[0049] Different amounts (0.01 g, 0.02 g, 0.03 g, 0.05 g, 0.08 g) of 4-dimethylaminopyridine (as an additive) were weighed and dissolved in 30 mL of acetone, respectively. Then, an excess of chrysin raw material α-crystal (purchased from Shaanxi Linzhou Biotechnology Co., Ltd.; the saturated solubility of chrysin in acetone solvent is 4 g / L) was added, and the mixture was reacted in a constant temperature shaker at 35°C and 220 rpm for 6 hours. During this process, all the additives were precipitated. The resulting solution was filtered, and the filtrate was naturally evaporated at room temperature to precipitate chrysin β-crystal.

[0050] like Figure 3 As shown, it is the PXRD pattern of the product obtained at different additive dosages of the present invention. It can be seen that when the additive dosage is less than 0.02 g, a new crystal form of chrysin cannot be formed.

[0051] 2. Screening of organic solvent types

[0052] Weigh 0.05 g of 4-dimethylaminopyridine and dissolve it in 30 mL of different organic solvents (acetonitrile, ethyl acetate, dichloromethane, acetone, ethanol), then add excess chrysin raw material α crystal, and react in a constant temperature shaker at 35°C and 220 rpm for 6 hours. During this process, all the additives are precipitated, the resulting solution is filtered, and the filtrate is naturally evaporated at room temperature to precipitate chrysin β crystal.

[0053] like Figure 4 As shown, the PXRD patterns of the products obtained in different organic solvents of the present invention are shown. It can be seen that acetone is the best solvent, followed by dichloromethane and ethyl acetate, ethanol is not ideal, and acetonitrile fails. The choice of solvent in this study is related to its volatility. A volatile solvent will crystallize the desired target crystal form faster and better, while N,N-dimethylformamide and N,N-dimethyl sulfoxide are solvents with high viscosity and are difficult to volatilize, so they cannot be used for experiments.

[0054] Experimental Example 2 Preparation of β-crystalline chrysin and structural characterization

[0055] Weigh 0.15 g of 4-dimethylaminopyridine and dissolve it in 50 mL of acetone, then add excess chrysin raw material α crystal, and react in a constant temperature shaker at 35°C and 220 rpm for 6 hours. During this process, all additives are precipitated. The resulting solution is filtered, and the filtrate is naturally evaporated at room temperature to precipitate chrysin β crystal.

[0056] The characterization test method of the present invention is as follows:

[0057] 1. PXRD

[0058] The α-crystal form of chrysin raw material and the β-crystal form of chrysin were characterized by X-ray powder diffractometer (PXRD). Figure 5 and Figures 6-7 It can be seen that the characteristic peak values ​​(2θ±0.2°) of the existing chrysin raw material α crystal are: 7.51, 12.71, 14.96, 17.82, 20.76, 22.38, 25.04, 27.86. The characteristic peak values ​​(2θ±0.2°) of the chrysin β crystal prepared by the present invention are: 7.03, 8.38, 9.16, 11.92, 12.52, 13.82, 15.68, 19.81, 22.38, 24.83, 26.64.

[0059] 2.DSC

[0060] Differential scanning calorimetry (DSC) was used to characterize the α-crystalline form of chrysin raw material and the β-crystalline form of chrysin. Figure 8 and Fig. 9It can be seen that the melting point of the existing chrysin raw material α crystal form is 288±0.3°C, while the melting point of the chrysin β crystal form prepared by the present invention is 157±0.3°C.

[0061] 3. TG

[0062] Thermogravimetric analysis (TG) was used to characterize the α and β crystal forms of chrysin. Fig.10 (Reference: Master's degree thesis of Liaocheng University, Study on co-crystals for the purpose of improving the pharmaceutical activity of flavonoids and reducing the hepatotoxicity of anti-tuberculosis drugs) and Fig.11 It can be seen that the chrysin α crystal has only one weight loss step starting at 281°C, while the chrysin β crystal has two weight loss steps starting at 152°C and 287°C, confirming that it has a new crystal form. In addition, during the heating process, the β crystal did not show obvious weight loss before 152°C, confirming that the β crystal is a polymorph that is anhydrous or does not contain other solvents.

[0063] 4. Dissolution performance

[0064] The dissolution behavior of chrysin α and β crystals in aqueous solution at 37°C was characterized by UV-visible spectrometry at a wavelength of 270 nm. Fig.12 It can be seen that the maximum solubility of the α-crystal form of chrysin raw material is 1.07×10 -8 g / g; while the maximum solubility of chrysin β-crystal is 0.04g / g. Compared with the α-crystal of chrysin raw material, the newly emerged β-crystal far exceeds the raw material in terms of dissolution rate and dissolution, providing a promising prospect for its use in pharmaceutical development.

[0065] For the traditional Chinese medicine chrysin, the higher the drug solubility and the faster the dissolution rate, the higher its absorption rate and bioavailability. As can be seen from the above, the chrysin β crystal obtained by the present invention has important value in promoting the application and development of chrysin drugs.

[0066] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A polymorph of chrysin, characterized in that: The polymorph is a metastable crystal form, and its crystal form is recorded as β crystal form. Its X-ray powder diffraction spectrum has characteristic peaks at 2θ values ​​of 7.03, 8.38, 9.16, 11.92, 12.52, 13.82, 15.68, 19.81, 22.38, 24.83, and 26.64, and the 2θ error range is ±0.2°.

2. The polymorph according to claim 1, characterized in that The X-ray powder diffraction pattern of the polymorph is substantially as shown in FIG6 .

3. The polymorph according to claim 1, characterized in that The X-ray powder diffraction pattern of the single crystal of the polymorph is substantially as shown in FIG7 .

4. The polymorph according to claim 1, characterized in that The polymorph has endothermic peaks in the ranges of 152°C to 162°C and 287°C to 299°C.

5. The polymorph according to claim 4, characterized in that The DSC graph of the polymorph is substantially as shown in FIG9 .

6. The polymorph according to claim 4, characterized in that The melting point of the polymorph is 157±0.3°C.

7. The polymorph according to claim 1, characterized in that The TG diagram of the polymorph is basically shown in FIG11 .

8. The method for preparing a polymorph according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (1) providing a first mixed solution, wherein the first mixed solution is obtained by dissolving an additive and an organic solvent; (2) adding an excess amount of existing chrysin to the first mixed solution obtained in step (1) to completely precipitate the additive; (3) filtering the mixed solution obtained in step (2); (4) placing the filtrate obtained in step (3) to allow the solvent to evaporate, and waiting for solid precipitation to obtain β-crystal chrysin; The existing chrysin crystal form is defined as an α-crystal form, and its X-ray powder diffraction spectrum has characteristic peaks at 2θ values ​​of 7.51, 12.71, 14.96, 17.82, 20.76, 22.38, 25.04, and 27.86, and the 2θ error range is ±0.2°; The additive is selected from 4-dimethylaminopyridine; The additive is used in the organic solvent in an amount ratio of not less than 0.002 g: 3 mL; The organic solvent is selected from any one of acetone, dichloromethane, chloroform, 1,2-dichloroethane and ethyl acetate.

9. The preparation method according to claim 8, characterized in that: In step (2), an excess amount of existing chrysin is added to the first mixed solution, and the mixture is reacted in a constant temperature shaker at 35° C. and 220 rpm.

10. The preparation method according to claim 9, characterized in that: The reaction time is 6 hours.

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