Dihydroartemisinic acid crystal as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of pharmaceutical chemistry, and provides a dihydroarteannuic acid crystal and a preparation method and application thereof, and in an X-ray powder diffraction pattern under Cu-K alpha radiation, the dihydroarteannuic acid crystal has characteristic peaks at diffraction angles 2 theta of 6.43 + / -0.2 degrees, 12.46 + / -0.2 degrees, 14.43 + / -0.2 degrees, 19.78 + / -0.2 degrees and 21.41 + / -0.2 degrees. The dihydroarteannuic acid crystal has a novel crystal structure, is high in purity, excellent in stability and convenient to produce and store, can fully meet the stability requirements in applications such as pharmaceutical preparations and the like, and has a wide application prospect. Moreover, the preparation process of the dihydroartemisinic acid crystal is simple, the used reagent is safe, 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 particularly relates to a dihydroartemisinic acid crystal, a preparation method and an application thereof. Background Art

[0002] Dihydroartemisinic acid (CAS No. 85031-59-0) is one of the sesquiterpenoid components in Artemisia annua L., and its molecular formula is C 15 H 24 O2, the molecular structure is It is one of the most important intermediates in the synthesis and metabolism of artemisinin and its derivatives. In recent years, dihydroartemisinic acid has attracted increasing attention from scientists. The evaluation of its physicochemical properties, crystal form, in vitro and in vivo release, in vivo metabolism, bioavailability, and biological activity is of great significance.

[0003] LNMISRA et al. published a paper titled “Crystal Structure of Artemisinic Acid: A Possible Biogenetic Precursor of Antimalarial Aremisinin From Artemisia Annua” (Journal of Natural Products, 1993, 56(2), 215-219), which reported on the X-ray study of crystals of hydrogen-bonded artemisinic acid dimers, discussed the infrared spectrum, electron bombardment mass spectrometry, chemical ion mass spectrometry data and X-ray crystallography results of artemisinic acid, but did not involve dihydroartemisinic acid crystals. Shuqian Liu et al. published a paper titled “Preparative Separation of High-purity Dihydroartemisinic Acid from Aretemisinin Production Waste by Combined Chromatography” (Chem. Pharm. Bull, 2018, 66(3): 319), which reported the single crystal structures of two dihydroartemisinic acid derivatives 28 and 32, but did not disclose the crystal form data of dihydroartemisinic acid monomers.

[0004] CN110143864A discloses a method for removing oil from crude dihydroartemisinic acid to prepare high-purity dihydroartemisinic acid, comprising the following steps: (1) preliminary crystallization; (2) centrifugal deoiling; (3) dissolution deoiling; (4) recrystallization; (5) decolorization crystallization; (6) secondary decolorization recrystallization; (7) drying; and (8) crushing and packaging. The method uses crude dihydroartemisinic acid as raw material, and can remove most of the oil impurities in the crude dihydroartemisinic acid through centrifugation, solvent extraction, and multiple dissolution deoiling and crystallization steps to prepare high-purity dihydroartemisinic acid. CN103524527A discloses a method for simultaneously extracting artemisinic acid and dihydroartemisinic acid from waste liquid after artemisinin separation. The method comprises the following steps: 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 subjected to urea inclusion treatment to remove some saturated and monounsaturated fatty acids; and then the product is recrystallized multiple times using ethyl acetate, chloroform, petroleum ether, and ether to obtain mixed crystals of dihydroartemisinic acid and artemisinic acid with a total content of not less than 95%. CN111533653A discloses a method for separating and purifying dihydroartemisinic acid from waste artemisinin wax oil, comprising the following steps: 1) adding purified water to the waste artemisinin wax oil, heating to remove residual organic solvent in the wax oil, cooling, adding petroleum ether, adding an alkaline substance to adjust the pH, heating under reflux and stirring; 2) cooling to room temperature, separating the layers, removing the aqueous layer, centrifuging and concentrating; 3) adding an acidic substance to adjust the pH; 4) adding petroleum ether, heating and stirring, cooling and separating the layers, taking the petroleum ether layer, and extracting twice; 5) combining the petroleum ether layers, concentrating under reduced pressure, cooling and crystallizing to obtain crude dihydroartemisinic acid crystals; 6) adding 80% ethanol solution to the crude dihydroartemisinic acid crystals, stirring until completely dissolved, adding activated carbon, stirring and decolorizing, filtering to remove the activated carbon, recovering the ethanol, cooling the remaining aqueous solution, crystallizing, filtering and drying to obtain high-purity colorless dihydroartemisinic acid crystals. This method has high separation efficiency and a simple separation process, and the obtained dihydroartemisinic acid is of high purity. CN116924903A discloses a process for extracting a mixture of dihydroartemisinic acid and artemisinic acid, comprising the following steps: dissolving and filtering artemisinin wax oil, mixing the filtrate with column chromatography silica gel, evaporating, separating by silica gel column chromatography, eluting with a mixed solvent of petroleum ether / acetic acid or n-hexane / acetic acid, detecting the components of the eluate by thin-layer chromatography, collecting fractions containing dihydroartemisinic acid and artemisinic acid, recovering the solvent to an extract form, dissolving with petroleum ether, extracting with an equal volume of sodium carbonate solution, and centrifuging. After centrifugation, acidifying the alkaline solution to precipitate a solid, filtering, washing with water until neutral, and repeating the same process on the precipitate to obtain a crude product of the dihydroartemisinic acid and artemisinic acid mixture, wherein the artemisinic acid content is 2.0-17.0% and the dihydroartemisinic acid content is 7.6-74.6%.

[0005] Although existing technologies disclose methods for the preparation and purification of dihydroartemisinic acid, these methods still have significant shortcomings. For example, some methods have difficulty achieving high purity, some process steps are cumbersome, and the solvents used are unsafe and environmentally unsafe. Some methods also produce dihydroartemisinic acid of insufficient purity and poor stability, failing to meet the technical requirements for pharmaceutical formulations. Furthermore, the prior art lacks in-depth research on dihydroartemisinic acid crystallization, and in particular, research on stable dihydroartemisinic acid crystalline forms remains unresolved. Therefore, the development of new, highly stable dihydroartemisinic acid crystalline forms and methods for their preparation are urgent challenges in the field. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention aims to provide a dihydroartemisinic acid crystal and a preparation method and application thereof. The dihydroartemisinic acid crystal has high purity, good stability, is easy to achieve industrial production, and has 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 a dihydroartemisinic acid crystal, wherein the dihydroartemisinic acid crystal has characteristic peaks at diffraction angles 2θ of 6.43±0.2°, 12.46±0.2°, 14.43±0.2°, 19.78±0.2° and 21.41±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 dihydroartemisinic acid crystals have characteristic peaks at diffraction angles 2θ of 6.43±0.2°, 12.46±0.2°, 14.43±0.2°, 19.78±0.2°, 21.41±0.2°, 25.28±0.2°, 27.14±0.2°, 29.14±0.2°, 38.09±0.2° and 42.84±0.2° in the X-ray powder diffraction pattern under Cu-Kα radiation.

[0011] The dihydroartemisinic acid crystals provided by the present invention have a specific new crystalline structure, high purity, and excellent stability. They are particularly stable under harsh conditions such as light, humidity, heat, acid, alkali, and strong oxidation. They are easy to produce and store, fully meet the stability requirements for applications such as the preparation of pharmaceutical preparations, and have broad application prospects. Furthermore, the preparation process of the dihydroartemisinic 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 dihydroartemisinic 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 14.43±0.2° 100％ 12.46±0.2° 71.8±0.1％ 6.43±0.2° 27.6±0.1％ 19.78±0.2° 34.5±0.1％ 21.41±0.2° 22.8±0.1％ 25.28±0.2° 10.7±0.1％ 27.14±0.2° 14.5±0.1％ 29.14±0.2° 4.6±0.1％ 38.09±0.2° 6.5±0.1％ 42.84±0.2° 5.0±0.1％

[0014] Preferably, in the X-ray powder diffraction pattern of the dihydroartemisinic 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] 2θ Relative peak intensity 14.43±0.2° 100.0％ 12.46±0.2° 71.8％ 6.43±0.2° 27.6％ 19.78±0.2° 34.5％ 21.41±0.2° 22.8％ 25.28±0.2° 10.7％ 27.14±0.2° 14.5％ 29.14±0.2° 4.6％ 38.09±0.2° 6.5％ 42.84±0.2° 5.0％ .

[0016] Preferably, in the X-ray powder diffraction pattern of the dihydroartemisinic acid crystals under Cu-Kα radiation, the characteristic peaks represented by the diffraction angle 2θ and the interplanar spacing (d) are as follows:

[0017]

[0018]

[0019] Further preferably, in the X-ray powder diffraction pattern of the dihydroartemisinic 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] For example, in the X-ray powder diffraction test of the dihydroartemisinic acid crystal under Cu-Kα radiation, λ is

[0022] Preferably, the infrared absorption spectrum of the dihydroartemisinic acid crystals has an absorption peak at the following wavenumbers: 3226±2cm -1 , 2914±2cm -1 , 1732±2cm -1 , 1699±2cm -1 , 1516±2cm -1 , 1406±2cm -1 , 1377±2cm -1 , 1294±2cm -1 , 1255±2cm -1 , 1226±2cm -1 , 1207±2cm -1 , 1112±2cm -1 , 1085±2cm -1 , 1012±2cm -1 , 991±2cm-1 , 977±2cm -1 , 954±2cm -1 , 941±2cm -1 , 920±2cm -1 , 854±2cm -1 , 796±2cm -1 , 771±2cm -1 , 700±2cm -1 , 684±2cm -1 , 563±2cm -1 , 536±2cm -1 , 503±2cm -1 , 437±2cm -1 .

[0023] Illustratively, the infrared absorption spectrum of the dihydroartemisinic acid crystals is tested using KBr pellets.

[0024] Preferably, the melting point without decomposition in the differential scanning calorimetry (DSC) analysis of the dihydroartemisinic acid crystals is 138-141°C, for example, it can be 138.2°C, 138.5°C, 138.8°C, 139°C, 139.2°C, 139.5°C, 139.8°C, 140°C, 140.2°C, 140.5°C or 140.8°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.

[0025] Illustratively, the heating rate in the DSC analysis of the dihydroartemisinic acid crystals is 10°C / min.

[0026] Preferably, the purity of the dihydroartemisinic acid crystals is ≥99%, 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.

[0027] In a second aspect, the present invention provides a method for preparing dihydroartemisinic acid crystals as described in the first aspect, the preparation method comprising:

[0028] Providing a dihydroartemisinic acid solution, the dihydroartemisinic acid solution comprising a combination of crude dihydroartemisinic acid and a crystallization solvent, wherein the crystallization solvent is a mixture of ethyl acetate and an alcohol solvent;

[0029] The dihydroartemisinic acid solution is subjected to crystallization treatment to obtain the dihydroartemisinic acid crystals.

[0030] In the present invention, the dihydroartemisinic acid crystals are obtained by crystallizing crude dihydroartemisinic acid in a specific crystallization solvent, which is simple to operate, uses a safe crystallization solvent, has low production costs, and is easy to achieve industrial-scale production.

[0031] Preferably, the purity of the crude dihydroartemisinic acid (mass content of dihydroartemisinic 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 said range.

[0032] Preferably, based on the mass of the crude dihydroartemisinic 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.

[0033] Preferably, the alcohol solvent comprises methanol and / or ethanol.

[0034] 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.

[0035] Preferably, the dihydroartemisinic acid solution further comprises activated carbon, and the crystallization treatment further comprises a filtration step.

[0036] As a preferred technical solution of the present invention, activated carbon is used to perform adsorption decolorization and purification treatment on the crude dihydroartemisinic acid, thereby obtaining dihydroartemisinic acid crystals of higher purity; before the crystallization treatment, the activated carbon (activated carbon that has completed adsorption decolorization) is removed by filtration.

[0037] Preferably, the preparation method of the dihydroartemisinic acid solution comprises: mixing crude dihydroartemisinic acid, a crystallization solvent and activated carbon, fully dissolving the crude dihydroartemisinic acid, and then filtering to obtain the dihydroartemisinic acid solution.

[0038] Preferably, the crude dihydroartemisinic acid is fully dissolved by heating, and the heating temperature is 40-80°C, for example, 42°C, 45°C, 48°C, 50°C, 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 said range.

[0039] Preferably, based on the mass of the crude dihydroartemisinic 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 enumerates the specific points included in the said range.

[0040] 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.

[0041] 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.

[0042] Preferably, the crystallization treatment further includes the steps of solid-liquid separation, washing and drying.

[0043] Preferably, the solid-liquid separation method comprises filtration.

[0044] Preferably, the washing solvent used in the washing comprises an alcohol solvent, more preferably methanol and / or ethanol.

[0045] Preferably, the drying method comprises drying under reduced pressure.

[0046] 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.

[0047] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0048] (1) mixing crude dihydroartemisinic acid, a crystallization solvent, and activated carbon, dissolving the mixture at 40-80° C., and then filtering the mixture to obtain a dihydroartemisinic acid solution;

[0049] Based on the mass of the crude dihydroartemisinic 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;

[0050] The crystallization solvent is a mixture of ethyl acetate and an alcohol solvent, the volume percentage of ethyl acetate in the crystallization solvent is 10-90%, and the alcohol solvent includes methanol and / or ethanol;

[0051] (2) The dihydroartemisinic 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 dihydroartemisinic acid crystals.

[0052] In a third aspect, the present invention provides a use of the dihydroartemisinic acid crystals as described in the first aspect in the preparation of medicines or cosmetics.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] (1) The dihydroartemisinic acid crystals provided by the present invention have a new crystalline structure, are characterized by high purity and good stability, and have a purity of ≥99%. They can remain stable under conditions such as light, moisture, heat, acid, alkali, and strong oxidation, are easy to produce and store, can fully meet the stability requirements in applications such as pharmaceutical preparations, and have broad application prospects.

[0055] (2) The preparation method of dihydroartemisinic acid crystals provided by the present invention is simple, the crystallization reagents used are safe, the production cost is low, and it is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The X-ray powder diffraction pattern of the dihydroartemisinic acid crystals provided in Example 1;

[0057] Figure 2 This is the DSC test chart of the dihydroartemisinic acid crystals provided in Example 1;

[0058] Figure 3This is the infrared absorption spectrum of the dihydroartemisinic acid crystals provided in Example 1;

[0059] Figure 4 This is the HPLC test chart of the dihydroartemisinic acid crystals provided in Example 1. DETAILED DESCRIPTION

[0060] 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.

[0061] 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.

[0062] 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:

[0063] (1) Crude dihydroartemisinic acid: Batch number 20250301, provided by Yunnan Specialty Plant Extraction Laboratory;

[0064] (2) Dihydroartemisinic acid reference substance: batch number DST250124-038, purchased from Chengdu Lemeitian Pharmaceutical Technology Co., Ltd.

[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 dihydroartemisinic acid peak, should be no less than 5000;

[0082] Determination 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] The dihydroartemisinic acid crystals and the preparation method thereof of the present invention are described in detail below using a number of examples as examples, but the dihydroartemisinic acid crystals and the preparation method thereof of the present invention are not limited to these examples.

[0095] Example 1

[0096] A dihydroartemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0097] (1) 100 g of crude dihydroartemisinic acid was added to 800 mL of a crystallization solvent (a mixture of ethyl acetate and ethanol, wherein the volume content of ethyl acetate was 30%), 5 g of activated carbon was added, and the solution was heated at 77°C to completely dissolve the solution. The solution was filtered to obtain a dihydroartemisinic acid solution.

[0098] (2) The dihydroartemisinic acid solution obtained in step (1) was allowed to stand at 25° C. for 72 h to allow crystals to slowly precipitate. The solution was filtered, washed with ethanol, and dried under reduced pressure at 30° C. to obtain 71 g of dihydroartemisinic acid crystals with a yield of 71%. The content of the crystals was determined by HPLC to be 99.4%.

[0099] The dihydroartemisinic acid crystals provided in this embodiment were tested and their Cu-Kα radiation, The X-ray powder diffraction pattern is as follows Figure 1 The characteristic peaks, interplanar spacing (d value) and relative peak intensity (I / I0) expressed in terms of diffraction angle 2θ are shown in Table 1:

[0100] Table 1

[0101]

[0102]

[0103] Combine Figure 1 As shown in Table 1, the dihydroartemisinic acid crystals provided by the present invention are a new crystalline form.

[0104] The DSC test graph of the dihydroartemisinic acid crystals provided in this embodiment is as follows: Figure 2 As shown, the melting point without decomposition in DSC analysis is 138-141°C.

[0105] The infrared absorption spectrum of the dihydroartemisinic acid crystals provided in this example is as follows: Figure 3 As shown, it has an absorption peak at the following wave number: 3226cm -1 , 2914cm-1 , 1732cm -1 , 1699cm -1 , 1516cm -1 , 1406cm -1 , 1377cm -1 , 1294cm -1 , 1255cm -1 , 1226cm -1 , 1207cm -1 , 1112cm -1 , 1085cm -1 , 1012cm -1 , 991cm -1 , 977cm -1 , 954cm -1 , 941cm -1 , 920cm -1 , 854cm -1 , 796cm -1 , 771cm -1 , 700cm -1 , 684cm -1 , 563cm -1 , 536cm -1 , 503cm -1 , 437cm -1 .

[0106] The HPLC test chart of dihydroartemisinic acid crystals provided in this example is as follows Figure 4 As shown, its purity (content) is 99.4%.

[0107] Example 2

[0108] A dihydroartemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0109] (1) 100 g of crude dihydroartemisinic acid was added to 500 mL of a crystallization solvent (a mixture of ethyl acetate and ethanol, wherein the volume content of ethyl acetate was 50%), and 3 g of activated carbon. The solution was heated at 78° C. to completely dissolve the solution, and filtered to obtain a dihydroartemisinic acid solution.

[0110] (2) The dihydroartemisinic acid solution obtained in step (1) was allowed to stand at 10° C. for 48 h to allow crystals to slowly precipitate. The solution was filtered, washed with ethanol, and dried under reduced pressure at 40° C. to obtain 80 g of dihydroartemisinic acid crystals with a yield of 80%. The content of the dihydroartemisinic acid crystals was determined by HPLC to be 99.1%. The dihydroartemisinic acid crystals provided in this example were tested by X-ray powder diffraction, confirming that their crystal structure was the same as that in Example 1.

[0111] Example 3

[0112] A dihydroartemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0113] (1) 100 g of crude dihydroartemisinic acid was added to 600 mL of a crystallization solvent (a mixture of ethyl acetate and methanol, wherein the volume content of ethyl acetate was 50%), 5 g of activated carbon, and the solution was heated at 77°C to completely dissolve the solution. The solution was filtered to obtain a dihydroartemisinic acid solution.

[0114] (2) The dihydroartemisinic acid solution obtained in step (1) was allowed to stand at 10° C. for 72 h to allow crystals to slowly precipitate. The solution was filtered, washed with methanol, and dried under reduced pressure at 25° C. to obtain 77 g of dihydroartemisinic acid crystals with a yield of 77%. The content of the dihydroartemisinic acid crystals measured by HPLC was 99.3%. The dihydroartemisinic acid crystals provided in this example were tested by X-ray powder diffraction, confirming that their crystal structure was the same as that in Example 1.

[0115] Example 4

[0116] A dihydroartemisinic acid crystal and a preparation method thereof, the preparation method comprising the following steps:

[0117] (1) 100 g of crude dihydroartemisinic acid was added to 900 mL of a crystallization solvent (a mixture of ethyl acetate and methanol, wherein the volume content of ethyl acetate was 60%), 5 g of activated carbon was added, and the solution was heated at 70° C. to completely dissolve the solution. The solution was filtered to obtain a dihydroartemisinic acid solution.

[0118] (2) The dihydroartemisinic acid solution obtained in step (1) was allowed to stand at 25° C. for 72 h to allow crystals to slowly precipitate. The solution was filtered, washed with methanol, and dried under reduced pressure at 30° C. to obtain 82 g of dihydroartemisinic acid crystals with a yield of 82%. The content of the obtained crystals was determined to be 99.5% by HPLC. The dihydroartemisinic acid crystals provided in this example were tested by X-ray powder diffraction, confirming that the crystal structure was the same as that in Example 1.

[0119] Comparative Example 1

[0120] A dihydroartemisinic acid crystal 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. The types, amounts, and process parameters of other materials are the same as those in Example 3, to obtain dihydroartemisinic acid crystals.

[0121] Comparative Example 2

[0122] A dihydroartemisinic acid crystal 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 dihydroartemisinic acid crystals.

[0123] Comparative Example 3

[0124] A dihydroartemisinic acid crystal 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 50%). The types, amounts, and process parameters of other materials are the same as those in Example 3, to obtain dihydroartemisinic acid crystals.

[0125] The stability test of the aforementioned dihydroartemisinic acid crystals was conducted using a dihydroartemisinic acid reference substance (batch number DST250124-038) as a comparison. The specific method is as follows:

[0126] (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.

[0127] (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.

[0128] (3) Strong oxidative damage: Accurately weigh 10 mg of the sample to be tested into a 10 mL volumetric flask, add 1 mL of hydrogen peroxide (H2O2 concentration is 5%) solution, mix well, and let it stand at room temperature for 1 h; then dissolve it with methanol, dilute it, and make it up to 0.5 mg / mL, and shake it well.

[0129] (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.

[0130] (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.

[0131] The destroyed samples were subjected to HPLC test, and the obtained peak area percentage data are shown in Table 2:

[0132] Table 2

[0133]

[0134] Combined with the test data in Table 2, it can be seen that compared with the commercially available dihydroartemisinic acid reference substance, the dihydroartemisinic acid crystals provided by the present invention, after being destroyed by strong acid, strong alkali, strong oxidation, high temperature, and strong light, the stability of the sample is reflected by the percentage of the main peak area of the undamaged sample, indicating that it can remain stable under harsh conditions such as light, heat, acid, alkali, and strong oxidation, has excellent stability, and is easy to produce and store.

[0135] The HPLC peak areas of each dihydroartemisinic 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:

[0136] Table 3

[0137]

[0138] Combined with the test data in Table 3, it can be seen that the present invention obtains a new crystalline form of dihydroartemisinic 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 crystalline structure of the present invention and have significantly poorer stability.

[0139] The applicant states that while the above-described embodiments illustrate the dihydroartemisinic 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. A dihydroartemisinic acid crystal, characterized in that: In the X-ray powder diffraction pattern of the dihydroartemisinic acid crystals under Cu-Kα radiation, characteristic peaks are present at diffraction angles 2θ of 6.43±0.2°, 12.46±0.2°, 14.43±0.2°, 19.78±0.2° and 21.41±0.2°.

2. The dihydroartemisinic acid crystal according to claim 1, characterized in that In the X-ray powder diffraction pattern of the dihydroartemisinic acid crystals under Cu-Kα radiation, characteristic peaks are present at diffraction angles 2θ of 6.43±0.2°, 12.46±0.2°, 14.43±0.2°, 19.78±0.2°, 21.41±0.2°, 25.28±0.2°, 27.14±0.2°, 29.14±0.2°, 38.09±0.2° and 42.84±0.2°.

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

5. The dihydroartemisinic acid crystal according to any one of claims 1 to 4, characterized in that The infrared absorption spectrum of the dihydroartemisinic acid crystals has an absorption peak at the following wavenumbers: 3226±2cm -1 , 2914±2cm -1 , 1732±2cm -1 , 1699±2cm -1 , 1516±2cm -1 , 1406±2cm -1 , 1377±2cm -1 , 1294±2cm -1 , 1255±2cm -1 , 1226±2cm -1 , 1207±2cm -1 , 1112±2cm -1 , 1085±2cm -1 , 1012±2cm -1 , 991±2cm -1 , 977±2cm -1 , 954±2cm -1 , 941±2cm -1 , 920±2cm -1 , 854±2cm -1 , 796±2cm -1 , 771±2cm -1 , 700±2cm -1 , 684±2cm -1 , 563±2cm -1 , 536±2cm -1 , 503±2cm -1 , 437±2cm -1 .

6. The dihydroartemisinic acid crystal according to any one of claims 1 to 5, characterized in that The melting point without decomposition of the dihydroartemisinic acid crystals in differential scanning calorimetry analysis is 138-141°C.

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

8. The preparation method according to claim 7, characterized in that Based on the mass of the crude dihydroartemisinic acid product as 1 g, the volume of the crystallization solvent is 1-50 mL; Preferably, the alcohol solvent comprises methanol and / or ethanol; Preferably, the volume percentage of ethyl acetate in the crystallization solvent is 10-90%; Preferably, the dihydroartemisinic acid solution further comprises activated carbon, and the crystallization treatment further comprises a filtration step; Preferably, the preparation method of the dihydroartemisinic acid solution comprises: mixing crude dihydroartemisinic acid, a crystallization solvent and activated carbon, dissolving the crude dihydroartemisinic acid and then filtering to obtain the dihydroartemisinic acid solution; Preferably, based on the mass of the crude dihydroartemisinic acid as 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 dihydroartemisinic acid, a crystallization solvent, and activated carbon, dissolving the mixture at 40-80° C., and then filtering the mixture to obtain a dihydroartemisinic acid solution; Based on the mass of the crude dihydroartemisinic 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 volume percentage of ethyl acetate in the crystallization solvent is 10-90%, and the alcohol solvent includes methanol and / or ethanol; (2) The dihydroartemisinic 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 dihydroartemisinic acid crystals.

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

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