Artemisinic acid crystal as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pharmaceutical chemistry, and provides an arteannuic acid crystal and a preparation method and application thereof, and the arteannuic acid crystal has characteristic peaks at diffraction angles 2theta of 31.42 + / -0.2 degrees, 20.54 + / -0.2 degrees and 12.78 + / -0.2 degrees in an X-ray powder diffraction pattern under Cu-K alpha radiation. The arteannuic acid crystal has a specific novel crystal structure, is high in purity, good in stability and convenient to produce and store, can fully meet various technical requirements in applications such as preparation of pharmaceutical preparations and the like, and has a wide application prospect. The preparation method of the artemisinic acid crystal is simple to operate, the used crystallization reagent is safe, the dosage is small, the production cost is low, and industrial production is easy.

Description

Technical Field

[0001] The present invention belongs to the technical field of pharmaceutical chemistry, and in particular relates to artemisinic acid crystals, a preparation method and an application thereof. Background Art

[0002] Artemisic acid is one of the sesquiterpenoid components in Artemisia annua L. and is the most important intermediate in the synthesis and metabolism of artemisinin and its derivatives. The molecular formula of artemisinic acid is C 15 H 22 O2, molecular weight is 234.33, molecular structure is Artemisinic acid has multiple pharmacological activities, including antimalarial, antitumor, antipyretic, antibacterial, allelopathic, and anti-adipogenic effects. Artemisinic acid inhibits JNK-mediated downregulation of C / EBP-δ expression, thereby suppressing adipogenesis in hAMSCs and potentially serving as a supplemental therapy for weight loss (Artemisinic Acid is a Regulator of Adipocyte Differentiation and C / EBPδ Expression, Journal of Cellular Biochemistry, 2012, 113:2488–2499). Artemisinic acid inhibits melanogenesis through downregulation of C / EBPα-dependent expression of the HMG-CoA reductase gene (Food and Chemical Toxicology, 51 (2013), 225–230). Artemisinic acid is attracting more and more attention from scientists. Research on the physical and chemical properties, crystal form, in vitro and in vivo release, in vivo metabolism, and bioavailability of artemisinic acid is of great significance for the evaluation of the efficacy of artemisinic acid.

[0003] In the paper “Crystal Structure of Artemisinic Acid: A Possible Biogenetic Precursor of Antimalarial Aremisinin From Artemisia Annua” (Journal of Natural Products, 1993, 56(2), 215-219), LNMISRA, A.AHMAD et al. studied the crystals of hydrogen-bonded dimers of artemisinic acid by X-ray and discussed the infrared spectrum, electron bombardment mass spectrometry and chemical ion mass spectrometry data of artemisinic acid, but did not disclose the crystal form data of artemisinic acid monomer.

[0004] In recent years, the industry has conducted research on the preparation process of artemisinic acid. For example, CN103570739A discloses a method for separating artemisinic acid from Artemisia annua essential oil, which includes the steps of extraction, acidification, extraction, decolorization, concentration crystallization, and recrystallization purification, thereby achieving effective separation of artemisinic acid from Artemisia annua essential oil. CN103467274A discloses a method for preparing artemisinic acid, which first obtains an extract from Artemisia annua by supercritical CO2 extraction, then dissolves the Artemisia annua extract in sodium bicarbonate solution, filters the solution, adds petroleum ether, and then adjusts the pH to 3-5 with hydrochloric acid solution. The petroleum ether extract is collected, decolorized with activated carbon, concentrated to a small volume, and allowed to crystallize. The crystals are then recrystallized from anhydrous methanol. The obtained artemisinic acid content is 97.1-98.7%. CN118638004A discloses a method for extracting and isolating artemisinic acid from an Artemisia annua byproduct. The Artemisia annua byproduct is subjected to dissolution, extraction, acidification, and extraction to obtain an insoluble material. This insoluble material is dissolved in an organic solvent and crystallized to obtain artemisinic acid with a content of 88.01-98.79%. CN107011157A discloses a method for extracting artemisinic acid from an extract obtained by artemisinin production. The crude artemisinic acid crystals obtained by separation, elution, and crystallization from the extract are dissolved in petroleum ether and then recrystallized to obtain the finished artemisinic acid. CN103524527A discloses a method for simultaneously extracting artemisinic acid and dihydroartemisinic acid from waste liquid after artemisinin separation. First, molecular distillation technology is used to preliminarily enrich artemisinic acid and dihydroartemisinic acid in the waste liquid of Artemisia annua. Then, solvent extraction and acid-base methods are used to further separate the molecular distillation product to obtain an oily crude product. Finally, the oily crude product is encapsulated with urea to remove some saturated and monounsaturated fatty acids, and multiple crystallizations are carried out to obtain mixed crystals of dihydroartemisinic acid and artemisinic acid with a total content of not less than 95%.

[0005] Although various methods for preparing artemisinic acid are known in the prior art, these methods suffer from numerous shortcomings. These include the use of unsafe solvents (e.g., petroleum ether) in some methods, which pose flammability and explosion risks in large-scale production. Other methods also yield low purity and poor product stability, failing to meet the technical requirements for pharmaceutical formulations. Furthermore, the prior art lacks research on artemisinic acid crystallization, particularly on stable crystalline forms. Therefore, the development of new, highly stable crystalline forms of artemisinic acid and their preparation methods are key research areas in this field. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention aims to provide artemisinic acid crystals and their preparation method and application. The artemisinic acid crystals have a specific crystal structure, high purity, good stability, simple preparation method, safe reagents used, easy to achieve industrial production, and have broad application prospects.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an artemisinic acid crystal, wherein the artemisinic acid crystal has characteristic peaks at diffraction angles 2θ of 31.42±0.2°, 20.54±0.2° and 12.78±0.2° in an X-ray powder diffraction pattern under Cu-Kα radiation.

[0009] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0010] Preferably, the artemisinic acid crystals have characteristic peaks at diffraction angles 2θ of 31.42±0.2°, 20.54±0.2°, 12.78±0.2°, 9.36±0.2°, 14.06±0.2°, 15.47±0.2°, 19.36±0.2°, 21.56±0.2° and 26.69±0.2° in the X-ray powder diffraction pattern under Cu-Kα radiation.

[0011] The artemisinic acid crystals provided by the present invention have a specific new crystalline form with high purity and excellent stability. They remain stable under harsh conditions such as light, moisture, heat, acid, alkali, and strong oxidation, and do not undergo reactions such as degradation. They are easy to produce and store, fully meeting the stability requirements for applications such as the preparation of pharmaceutical preparations, and have broad application prospects. Furthermore, the preparation process of the artemisinic acid crystals is simple, the reagents used are safe, the production cost is low, and they are easy to industrialize.

[0012] Preferably, in the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks and relative peak intensities (I / I0) expressed in terms of diffraction angle 2θ are as follows:

[0013] 2θ Relative peak intensity 31.42±0.2° 100％ 20.54±0.2° 69.0±0.1％ 12.78±0.2° 59.2±0.1％ 9.36±0.2° 5.7±0.1％ 14.06±0.2° 9.1±0.1％ 15.47±0.2° 5.8±0.1％ 19.36±0.2° 9.2±0.1％ 21.56±0.2° 14.2±0.1％ 26.69±0.2° 5.3±0.1％

[0014] Further preferably, in the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks and relative peak intensities (I / I0) expressed in terms of diffraction angle 2θ are as follows:

[0015]

[0016]

[0017] Preferably, in the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks represented by the diffraction angle 2θ and the interplanar spacing (d) are as follows:

[0018]

[0019] Further preferably, in the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks represented by the diffraction angle 2θ and the interplanar spacing (d) are as follows:

[0020]

[0021]

[0022] For example, in the X-ray powder diffraction test of the artemisinic acid crystal under Cu-Kα radiation, λ is

[0023] Preferably, the infrared absorption spectrum of the artemisinic acid crystals has an absorption peak at the following wavenumbers: 2914±2cm -1 , 1689±2cm -1 , 1622±2cm -1 , 1448±2cm -1 , 1402±2cm -1 , 1377±2cm -1 , 1321±2cm -1 , 1296±2cm -1 , 1278±2cm -1 , 1217±2cm -1 , 1184±2cm -1 , 1159±2cm -1 , 1105±2cm -1 , 1029±2cm -1, 993±2cm -1 , 945±2cm -1 , 825±2cm -1 , 796±2cm -1 , 713±2cm -1 , 700±2cm -1 , 653±2cm -1 , 615±2cm -1 , 567±2cm -1 , 437±2cm -1 .

[0024] Illustratively, the infrared absorption spectrum of the artemisinic acid crystals is tested using KBr pellets.

[0025] Preferably, the melting point without decomposition in the differential scanning calorimetry (DSC) analysis of the artemisinic acid crystals is 129-131°C, for example, it can be 129.2°C, 129.5°C, 129.8°C, 130°C, 130.2°C, 130.5°C or 130.8°C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the said range.

[0026] Illustratively, the heating rate in the DSC analysis of the artemisinic acid crystals is 10°C / min.

[0027] Preferably, the melting point without decomposition temperature in the thermogravimetric-differential thermal analysis (TGA) of the artemisinic acid crystals is 129-131°C, for example, it can be 129.2°C, 129.5°C, 129.8°C, 130°C, 130.2°C, 130.5°C or 130.8°C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0028] Exemplarily, the heating rate in the TGA analysis of the artemisinic acid crystals is 10°C / min.

[0029] Preferably, the purity of the artemisinic acid crystals is ≥99.0%, for example, it can be 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, 99.95% or 99.99%, as well as specific values between the above points. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific points included in the said range.

[0030] In a second aspect, the present invention provides a method for preparing artemisinic acid crystals as described in the first aspect, the preparation method comprising the following steps:

[0031] Providing an artemisinic acid solution, the artemisinic acid solution comprising a combination of crude artemisinic acid and a crystallization solvent, wherein the crystallization solvent is a mixture of ethyl acetate and an alcohol solvent;

[0032] The artemisinic acid solution is subjected to crystallization treatment to obtain the artemisinic acid crystals.

[0033] In the present invention, the artemisinic acid crystals are obtained by crystallizing a crude artemisinic acid product in a crystallization solvent (ethyl acetate-alcohol solvent mixture) of specific components. The preparation method is simple, the crystallization solvent used is safe, the amount used is small, the production cost is low, and industrial production is easy to achieve.

[0034] Preferably, the purity of the crude artemisinic acid (mass content of artemisinic acid) is 95-98%, for example, it can be 95.2%, 95.5%, 96%, 96.5%, 97%, 97.5% or 97.8%, as well as specific values between the above points. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific values included in the range.

[0035] Preferably, the alcohol solvent includes methanol and / or ethanol.

[0036] Preferably, the volume percentage of ethyl acetate in the crystallization solvent is 10-90%, for example, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85%, as well as specific values between the above points. Due to space limitations and for the sake of brevity, the present invention does not exhaustively enumerate the specific values included in the above range.

[0037] Preferably, based on the mass of the crude artemisinic acid product of 1 g, the volume of the crystallization solvent is 1-50 mL, for example, 5 mL, 8 mL, 10 mL, 15 mL, 20 mL, 25 mL, 30 mL, 35 mL, 40 mL or 45 mL, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0038] Preferably, the artemisinic acid solution further comprises activated carbon, and the crystallization treatment further comprises a filtration step.

[0039] As a preferred technical solution of the present invention, activated carbon is used to perform adsorption decolorization and purification treatment on the crude artemisinic acid, thereby obtaining artemisinic acid crystals of higher purity; before the crystallization treatment, the activated carbon (activated carbon that has completed adsorption decolorization) is removed by filtration.

[0040] Preferably, the preparation method of the artemisinic acid solution comprises: mixing crude artemisinic acid, a crystallization solvent and activated carbon, dissolving the crude artemisinic acid and then filtering to obtain the artemisinic acid solution.

[0041] Preferably, the crude artemisinic acid is fully dissolved by heating, and the heating temperature is 50-80°C, for example, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, 70°C, 72°C, 75°C or 78°C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0042] Preferably, based on the mass of the crude artemisinic acid as 100%, the mass of the activated carbon is 0.1-5%, for example, it can be 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5% or 4.8%, as well as specific values between the above points. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific points included in the range.

[0043] Preferably, the temperature of the crystallization treatment is 0-40°C, for example, it can be 2°C, 5°C, 8°C, 10°C, 12°C, 15°C, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 35°C or 38°C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0044] Preferably, the crystallization treatment time is ≥12h, for example, it can be 15h, 18h, 20h, 24h, 28h, 30h, 32h, 36h, 40h, 44h, 48h, 50h, 52h, 56h, 60h, 64h, 68h, 70h, 72h, 76h, 80h, 84h, 88h or 92h, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range, and 12-84h is further preferred.

[0045] Preferably, the crystallization treatment further includes the steps of solid-liquid separation, washing and drying.

[0046] Preferably, the solid-liquid separation method comprises filtration.

[0047] Preferably, the solvent used for washing includes an alcohol solvent, more preferably methanol and / or ethanol.

[0048] Preferably, the drying method includes drying under reduced pressure.

[0049] Preferably, the drying temperature is 25-40°C, for example, it can be 26°C, 28°C, 30°C, 32°C, 34°C, 35°C, 36°C or 38°C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values included in the range.

[0050] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0051] (1) Mixing crude artemisinic acid, a crystallization solvent, and activated carbon, dissolving them at 50-80° C., and then filtering to obtain an artemisinic acid solution;

[0052] Based on the mass of the crude artemisinic acid product being 1 g, the volume of the crystallization solvent is 1-50 mL, and the mass of the activated carbon is 0.001-0.05 g;

[0053] The crystallization solvent is a mixture of ethyl acetate and an alcohol solvent, the alcohol solvent includes methanol and / or ethanol, and the volume percentage of ethyl acetate in the crystallization solvent is 10-90%;

[0054] (2) The artemisinic acid solution is allowed to stand at 0-40° C. for crystallization for ≥12 h, followed by solid-liquid separation, and the solid is collected, washed, and dried to obtain the artemisinic acid crystals.

[0055] In a third aspect, the present invention provides a use of the artemisinic acid crystals as described in the first aspect in the preparation of medicines or cosmetics.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The artemisinic acid crystals provided by the present invention have a specific new crystal structure with a purity of ≥99%. They can remain stable under conditions such as light, moisture, heat, acid, alkali, and strong oxidation. They have the characteristics of high purity and good stability, are easy to produce and store, can fully meet various technical requirements in applications such as the preparation of pharmaceutical preparations, and have broad application prospects.

[0058] (2) The method for preparing artemisinic acid crystals provided by the present invention is simple to operate, the crystallization reagents used are safe, the amount used is small, the production cost is low, and it is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is the X-ray powder diffraction pattern of the artemisinic acid crystals provided in Example 1;

[0060] Figure 2 DSC and TG-DTA test charts of artemisinic acid crystals provided in Example 1;

[0061] Figure 3 This is the infrared absorption spectrum of the artemisinic acid crystals provided in Example 1;

[0062] Figure 4 This is the HPLC test chart of artemisinic acid crystals provided in Example 1. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0064] As used herein, the terms "comprises," "including," "having," "containing" or any other variations thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises a listed element is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, or article.

[0065] In the following specific embodiments of the present invention, the test instruments and test methods used are as follows:

[0066] (1) X-ray powder diffraction test

[0067] Instrument: Japan Rigaku D / MAX-2200 diffractometer

[0068] Target: Cu-Kα radiation 2θ is 2°-90°;

[0069] Step angle: 0.04°;

[0070] Tube voltage: 36kV;

[0071] Tube current: 30mA;

[0072] Scanning speed: 10° / min;

[0073] Filter: Graphite monochromator.

[0074] (2) Infrared absorption spectrum test

[0075] Instrument: Shimadzu IR Tracer-100 Fourier transform infrared spectrometer, KBr pellets were used for testing.

[0076] (3) Purity (content) test

[0077] High performance liquid chromatography (HPLC) was used for testing. The instrument was an Agilent 1290 Infinity II HPLC instrument, including: G7104A pump, G7129B autosampler, G7117A diode array detector, G7116B column oven, and OpenLab workstation.

[0078] Chromatographic column: Octadecylsilane bonded silica gel was used as filler, Agilent InfinityLabPoroshell120EC-C18 (4.6×250nm×2.7μm);

[0079] Mobile phase: acetonitrile-0.1% phosphoric acid-5% tetrahydrofuran aqueous solution, volume ratio 60:40; acetonitrile, tetrahydrofuran, and phosphoric acid were chromatographic grade, and redistilled water was used for HPLC.

[0080] Detection wavelength: 205nm;

[0081] Theoretical plate number: calculated based on the artemisinic acid peak, should be no less than 5000;

[0082] Test method: Take about 10 mg of the sample to be tested, accurately weigh it, place it in a 10 mL volumetric flask, add petroleum ether, dissolve it at 60-90 ° C and dilute it to the scale, and mix it thoroughly; accurately measure 10 μL and inject it into the high performance liquid chromatograph, record the chromatogram; calculate the purity by peak area according to the external standard method.

[0083] (4) Differential scanning calorimetry (DSC) test

[0084] Instrument: METTLER TGA / DSC / HT1600 analyzer;

[0085] Temperature range: 25-400℃;

[0086] Heating rate: 10℃ / min.

[0087] (5) Thermogravimetric-differential thermal (TGA) test

[0088] Instrument: METTLER TGA / DSC / HT1600 analyzer;

[0089] TG range: 5mg;

[0090] DTA range: ±250μV;

[0091] Reference material: Al2O3;

[0092] Temperature range: 25-400℃;

[0093] Heating rate: 10℃ / min.

[0094] In the following specific embodiments of the present invention, the materials for which no preparation methods are provided are all commercially available chemicals. The specific information of some materials is shown in the following table:

[0095] (1) Crude artemisinic acid: batch number 20250228, provided by Yunnan Specialty Plant Extraction Laboratory;

[0096] (2) Artemisinic acid reference substance: batch number DSTDQ004802, purchased from Chengdu Lemeitian Pharmaceutical Technology Co., Ltd.

[0097] The artemisinic acid crystals and the preparation method thereof of the present invention are described in detail below using a number of examples, but the artemisinic acid crystals and the preparation method thereof of the present invention are not limited to these examples.

[0098] Example 1

[0099] An artemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0100] (1) 100 g of crude artemisinic acid was added to 5000 mL of a crystallization solvent (a mixture of ethyl acetate and ethanol, wherein the volume content of ethyl acetate was 70%), and 5 g of activated carbon. The mixture was heated at 77° C. to completely dissolve the artemisinic acid, and filtered to obtain an artemisinic acid solution.

[0101] (2) The artemisinic acid solution obtained in step (1) was allowed to stand at 25° C. for 72 h to allow crystals to slowly precipitate, filtered, washed with ethanol, and dried under reduced pressure at 30° C. to obtain 73 g of artemisinic acid crystals with a yield of 73%. The content was determined by HPLC to be 99.4%.

[0102] The artemisinic acid crystals provided in this embodiment were tested and found to be The X-ray powder diffraction pattern is as follows Figure 1 As shown, the characteristic peaks represented by the diffraction angle 2θ, the interplanar spacing (d value, ) and relative peak intensity (I / I0,%) are shown in Table 1:

[0103] Table 1

[0104]

[0105] according to Figure 1 As shown in Table 1, the artemisinic acid crystals provided by the present invention are a new crystalline form.

[0106] The DSC and TG-DTA (TGA) test diagrams of artemisinic acid crystals provided in this example are as follows: Figure 2 As shown, the melting temperature without decomposition in the DSC analysis is 129-131°C, and the melting temperature without decomposition in the TGA analysis is 129-131°C.

[0107] The infrared absorption spectrum of artemisinic acid crystals provided in this example is as follows Figure 3 As shown, it has an absorption peak at the following wave number: 2914cm -1 , 1689cm -1 , 1622cm -1 , 1448cm -1 , 1402cm -1 , 1377cm -1 , 1321cm -1 , 1296cm -1 , 1278cm -1 , 1217cm -1 , 1184cm -1 , 1159cm -1 , 1105cm -1 , 1029cm -1 , 993cm -1 , 945cm -1 , 825cm -1 , 796cm -1 , 713cm -1 , 700cm -1 , 653cm -1 , 615cm -1 , 567cm -1 , 437cm -1 .

[0108] The HPLC test chart of artemisinic acid crystals provided in this example is as follows Figure 4 As shown, its purity (content) is 99.4%.

[0109] Example 2

[0110] An artemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0111] (1) 100 g of crude artemisinic acid was added to 2000 mL of a crystallization solvent (a mixture of ethyl acetate and ethanol, wherein the volume content of ethyl acetate was 80%), and 3 g of activated carbon. The mixture was heated at 78° C. to completely dissolve the artemisinic acid, and filtered to obtain an artemisinic acid solution.

[0112] (2) The artemisinic acid solution obtained in step (1) was allowed to stand at 10° C. for 48 h to allow crystals to slowly precipitate, filtered, washed with ethanol, and dried under reduced pressure at 40° C. to obtain 81 g of artemisinic acid crystals with a yield of 81%. The content of the crystals was determined by HPLC to be 99.1%.

[0113] Example 3

[0114] An artemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0115] (1) 100 g of crude artemisinic acid was added to 5000 mL of a crystallization solvent (a mixture of ethyl acetate and methanol, wherein the volume content of ethyl acetate was 60%), and 5 g of activated carbon. The mixture was heated at 77°C to completely dissolve the artemisinic acid, and filtered to obtain an artemisinic acid solution.

[0116] (2) The artemisinic acid solution obtained in step (1) was allowed to stand at 10° C. for 48 h to allow crystals to slowly precipitate, filtered, washed with methanol, and dried under reduced pressure at 25° C. to obtain 76 g of artemisinic acid crystals with a yield of 76%. The content was determined by HPLC to be 99.8%.

[0117] Example 4

[0118] An artemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0119] (1) 100 g of crude artemisinic acid was added to 3000 mL of a crystallization solvent (a mixture of ethyl acetate and methanol, wherein the volume content of ethyl acetate was 75%), and 5 g of activated carbon. The mixture was heated at 70° C. to completely dissolve the artemisinic acid, and filtered to obtain an artemisinic acid solution.

[0120] (2) The artemisinic acid solution obtained in step (1) was allowed to stand at 25° C. for 72 h to allow crystals to slowly precipitate, which was then filtered, washed with methanol, and dried under reduced pressure at 30° C. to obtain 82 g of artemisinic acid crystals with a yield of 82%. The content of the crystals was determined by HPLC to be 99.5%.

[0121] Comparative Example 1

[0122] Artemisinic acid crystals and a preparation method thereof. The preparation method differs from Example 3 only in that the crystallization solvent is replaced with an equal volume of anhydrous methanol, and the types, amounts, and process parameters of other materials are the same as those in Example 3, to obtain artemisinic acid crystals.

[0123] Comparative Example 2

[0124] Artemisinic acid crystals and a preparation method thereof. The preparation method differs from Example 3 only in that the crystallization solvent is replaced with an equal volume of ethyl acetate, and the types, amounts, and process parameters of other materials are the same as those in Example 3, to obtain artemisinic acid crystals.

[0125] Comparative Example 3

[0126] Artemisinic acid crystals and a preparation method thereof. The preparation method differs from Example 3 only in that the crystallization solvent is replaced with an equal volume of methanol-water solution (the volume content of methanol is 95%). The types, amounts, and process parameters of other materials are the same as those in Example 3 to obtain artemisinic acid crystals.

[0127] The stability test of the aforementioned artemisinic acid crystals was performed using a commercially available artemisinic acid reference substance (batch number DSTDQ004802) as a comparison. The specific method is as follows:

[0128] (1) Strong acid destruction: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, add 1 mL of 0.1 mol / L hydrochloric acid aqueous solution, mix well, and let it stand at room temperature for 1 h; add 1 mL of 0.1 mol / L sodium hydroxide aqueous solution to neutralize it, then dissolve it with methanol, dilute it, and make it up to 0.5 mg / mL, and shake it well.

[0129] (2) Strong alkali destruction: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, add 1 mL of 0.1 mol / L sodium hydroxide aqueous solution, mix well, and let it stand at room temperature for 1 h; add 1 mL of 0.1 mol / L hydrochloric acid aqueous solution to neutralize it, then dissolve it with methanol, dilute it, and make it up to 0.5 mg / mL, and shake it well.

[0130] (3) Strong oxidative damage: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, add 1 mL of 5% hydrogen peroxide, mix well, let stand at room temperature for 1 h, then dissolve, dilute and adjust the volume to 1.0 mg / mL with methanol, and shake well.

[0131] (4) High temperature destruction: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, heat it at 60 °C for 2 h, then dissolve it in methanol, dilute it, and make it to 1.0 mg / mL, and shake it well.

[0132] (5) Strong light damage: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, place it under strong light conditions of 4500 lux for 240 h, then dissolve it in methanol, dilute it, and make it up to 1.0 mg / mL, and shake it well.

[0133] The destroyed samples were subjected to HPLC test, and the obtained peak area data are shown in Table 2:

[0134] Table 2

[0135]

[0136]

[0137] Combined with the test data in Table 2, it can be seen that compared with the commercially available artemisinic acid reference substance, the artemisinic acid crystals with a specific crystal form provided by the present invention are destroyed by strong acid, strong alkali, strong oxidation, high temperature, and strong light. The percentage of the main peak area of the undamaged sample reflects the stability of the sample, indicating that it can remain stable under light, heat, acid, alkali, and strong oxidation conditions without producing degradation by-products, has excellent stability, and is easy to produce and store.

[0138] The HPLC peak areas of each artemisinic acid sample after destruction by strong acid, strong base, strong oxidation, high temperature, and strong light were integrated and calculated to obtain the rate of change of the peak area after destruction. The smaller the rate of change, the better the stability of the sample. The data are shown in Table 3:

[0139] Table 3

[0140]

[0141] Combined with the test data in Table 3, it can be seen that the present invention obtains a new crystal form of artemisinic acid crystals through the design of the crystallization solvent. The HPLC peak area change rate after destruction by strong acid, strong base, strong oxidation, high temperature, and strong light is lower, indicating excellent stability. The crystals prepared in Comparative Examples 1-3 do not have the crystal structure of the present invention and have significantly poorer stability.

[0142] The applicant states that while the above-described embodiments illustrate the artemisinic acid crystals, their preparation methods, and applications, the present invention is not limited to the aforementioned process steps, nor does it necessarily rely on these process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for the raw materials used, additions of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. An artemisinic acid crystal, characterized in that: In the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, characteristic peaks are present at diffraction angles 2θ of 31.42±0.2°, 20.54±0.2° and 12.78±0.2°.

2. The artemisinic acid crystal according to claim 1, characterized in that In the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, characteristic peaks are present at diffraction angles 2θ of 31.42±0.2°, 20.54±0.2°, 12.78±0.2°, 9.36±0.2°, 14.06±0.2°, 15.47±0.2°, 19.36±0.2°, 21.56±0.2° and 26.69±0.2°.

3. The artemisinic acid crystal according to claim 1 or 2, characterized in that In the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks and relative peak intensities expressed by the diffraction angle 2θ are as follows: Preferably, in the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks and relative peak intensities expressed by the diffraction angle 2θ are as follows: 。 4. The artemisinic acid crystal according to any one of claims 1 to 3, characterized in that In the X-ray powder diffraction pattern of the artemisinic acid crystals under Cu-Kα radiation, the characteristic peaks and interplanar spacings expressed by the diffraction angle 2θ are as follows:

5. The artemisinic acid crystal according to any one of claims 1 to 4, characterized in that: The infrared absorption spectrum of the artemisinic acid crystals has an absorption peak at the following wavenumbers: 2914±2cm -1 , 1689±2cm -1 , 1622±2cm -1 , 1448±2cm -1 , 1402±2cm -1 , 1377±2cm -1 , 1321±2cm -1 , 1296±2cm -1 , 1278±2cm -1 , 1217±2cm -1 , 1184±2cm -1 , 1159±2cm -1 , 1105±2cm -1 , 1029±2cm -1 , 993±2cm -1 , 945±2cm -1 , 825±2cm -1 , 796±2cm -1 , 713±2cm -1 , 700±2cm -1 , 653±2cm -1 , 615±2cm -1 , 567±2cm -1 , 437±2cm -1 .

6. The artemisinic acid crystal according to any one of claims 1 to 5, characterized in that: The melting point without decomposition of the artemisinic acid crystals in differential scanning calorimetry analysis is 129-131°C; Preferably, the purity of the artemisinic acid crystals is ≥99.0%.

7. A method for preparing artemisinic acid crystals according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: Providing an artemisinic acid solution, the artemisinic acid solution comprising a combination of crude artemisinic acid and a crystallization solvent, wherein the crystallization solvent is a mixture of ethyl acetate and an alcohol solvent; The artemisinic acid solution is subjected to crystallization treatment to obtain the artemisinic acid crystals.

8. The preparation method according to claim 7, characterized in that The alcohol solvent includes methanol and / or ethanol; Preferably, the volume percentage of ethyl acetate in the crystallization solvent is 10-90%; Preferably, based on the mass of the crude artemisinic acid product being 1 g, the volume of the crystallization solvent is 1-50 mL; Preferably, the artemisinic acid solution further comprises activated carbon, and the crystallization treatment further comprises a filtration step; Preferably, the preparation method of the artemisinic acid solution comprises: mixing crude artemisinic acid, a crystallization solvent and activated carbon, dissolving the crude artemisinic acid, and then filtering to obtain the artemisinic acid solution; Preferably, based on the mass of the crude artemisinic acid being 100%, the mass of the activated carbon is 0.1-5%; Preferably, the temperature of the crystallization treatment is 0-40°C; Preferably, the crystallization treatment time is ≥12 h, more preferably 12-84 h; Preferably, the crystallization treatment further includes the steps of solid-liquid separation, washing and drying.

9. The preparation method according to claim 7 or 8, characterized in that The preparation method comprises the following steps: (1) Mixing crude artemisinic acid, a crystallization solvent, and activated carbon, dissolving them at 50-80° C., and then filtering to obtain an artemisinic acid solution; Based on the mass of the crude artemisinic acid product being 1 g, the volume of the crystallization solvent is 1-50 mL, and the mass of the activated carbon is 0.001-0.05 g; The crystallization solvent is a mixture of ethyl acetate and an alcohol solvent, the alcohol solvent includes methanol and / or ethanol, and the volume percentage of ethyl acetate in the crystallization solvent is 10-90%; (2) The artemisinic acid solution is allowed to stand at 0-40° C. for crystallization for ≥12 h, followed by solid-liquid separation, and the solid is collected, washed, and dried to obtain the artemisinic acid crystals.

10. Use of the artemisinic acid crystal according to any one of claims 1 to 6 in the preparation of medicines or cosmetics.

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