Baicalein co-amorphous substance, preparation and application thereof

Abstract

The application belongs to the field of medicine, and specifically discloses a baicalin co-amorphous substance, which is a co-amorphous substance formed by baicalin and a ligand, wherein the ligand is at least one of L-arginine, L-histidine and 2-aminopyridine. The application also includes a preparation method and application of the baicalin co-amorphous substance. The baicalin co-amorphous substance is an amorphous form completely different from a baicalin raw material crystal, and a powder X-ray diffraction spectrum does not have sharp diffraction peaks using Cu-Kα radiation. The baicalin co-amorphous substance provided by the application can effectively improve the poor solubility of baicalin, and is beneficial to improving the bioavailability of the drug.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical technology, specifically relating to the field of pharmaceutical co-amorphous materials. Technical Background

[0002] Baicalin is a flavonoid compound extracted from the root of Scutellaria baicalensis, a plant in the Lamiaceae family. Baicalin possesses antibacterial, anti-inflammatory, hypotensive, and anti-allergic biological activities, as well as strong antioxidant and anti-apoptotic properties. Studies have shown that baicalin can be used as a specific inhibitor of hepatic sialic acid oxidase in mammals to regulate certain diseases; it can also inhibit the activity of aldose reductase in the lens of rats, reducing the incidence of cataracts. Simultaneously, baicalin can induce apoptosis and differentiation of cancer cells, inhibit cancer cell migration, and reverse tumor drug resistance, and is clinically used to treat malignant tumors such as primary liver cancer and colon cancer. However, baicalin is almost insoluble in water, and its oral absorption and bioavailability are low, greatly limiting its clinical application.

[0003] To improve the solubility and bioavailability of baicalin, various methods have been reported in current research. For example, baicalin-containing nanoliposomes were prepared using foam dispersion and freeze-drying. Studies have shown that baicalin nanoliposomes have good anti-tumor therapeutic effects on nude mice with in situ human lung cancer, with a median survival time (25.90±0.53 days) that is significantly longer than that of the original baicalin (17.30±0.47 days), indicating significantly improved bioavailability. Using PBS buffer as the dissolution medium, F-127 hydrogel (a block copolymer composed of polyethylene oxide (PEO) and polypropylene oxide (PPO)) was selected as the drug carrier matrix. The prepared baicalin-F127 injectable hydrogel showed significantly increased solubility and a hemolysis percentage far below the maximum limit, exhibiting excellent blood biocompatibility and good cell compatibility. Supramolecular inclusion complexes of baicalin were prepared by encapsulating baicalin with β-cyclodextrin. Baicalin and β-cyclodextrin bind through hydrophobic and hydrogen bonding interactions. The prepared inclusion complexes show a shorter time to peak plasma concentration and increased solubility. While this method can increase the solubility and dissolution rate of baicalin to some extent, it has certain drawbacks. For example, the drug loading in the formulation may be too low, or the preparation process may require large amounts of organic solvents or stabilizers, resulting in long preparation times and high costs, making industrial-scale production or widespread use difficult.

[0004] Co-amorphous compounds are amorphous solid systems composed of two or more small molecules, including drug-drug or drug-non-drug combinations. They improve drug solubility and stability through various mechanisms, such as weak intermolecular interactions (e.g., hydrogen bonds, charge-assisted interactions) and improved component compatibility. A common approach is to use low-molecular-weight ligands (e.g., amino acids) to provide stable and rapidly dissolving mixtures. Co-amorphous compounds can improve the stability of amorphous drug monomers, as well as drug solubility and dissolution rate. Furthermore, combining two drugs with synergistic effects can produce synergistic pharmacological effects, improving clinical efficacy and reducing drug toxicity and adverse reactions.

[0005] Studies on the co-amorphous form of baicalin are scarce. Currently, only patent CN113995764A reports a method for preparing the co-amorphous form of baicalin and its formulation. Baicalin is metabolized into baicalin by enzymes in intestinal epithelial cells and the liver. Both baicalin and baicalin are ultimately absorbed into the bloodstream as baicalin. Therefore, even though the co-amorphous form of baicalin and baicalin reported in the aforementioned patent has good solubility in the gastrointestinal tract, it still cannot fundamentally improve the solubility of baicalin in the bloodstream, thereby failing to exert a therapeutic effect.

[0006] Therefore, there is an urgent need for a suitable preparation method or dosage form to improve the solubility of baicalin in a safe, economical and practical way, thereby increasing its bioavailability in vivo and realizing its clinical value. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide novel baicalin co-amorphous compounds that improve their solubility and synergistically enhance their bioavailability.

[0008] The second objective of this invention is to provide a method for preparing the aforementioned baicalin co-amorphous compound and its pharmaceutical applications.

[0009] A third objective of this invention is to provide a pharmaceutical composition comprising the baicalin co-amorphous product.

[0010] A co-amorphous compound of baicalin is a co-amorphous compound formed by baicalin and a ligand, wherein the ligand is at least one selected from L-arginine, L-histidine, and 2-aminopyridine.

[0011] This invention provides a novel co-amorphous compound formed by baicalin and a ligand comprising at least one of L-arginine, L-histidine, and 2-aminopyridine, which unexpectedly significantly improves its solubility. Furthermore, the combination of the ligand and baicalin can achieve synergistic effects in vivo, significantly improving its bioavailability.

[0012] In this invention, the baicalin co-amorphous compound is a substance formed by baicalin and ligands that does not have sharp diffraction peaks in its powder X-ray diffraction spectrum.

[0013] In this invention, the baicalin co-amorphous product includes at least one of baicalin / L-arginine co-amorphous product, baicalin / L-histidine co-amorphous product, and baicalin / 2-aminopyridine co-amorphous product;

[0014] In this invention, the baicalin / L-arginine co-amorphous compound was subjected to Cu-Kα radiation, and the powder X-ray diffraction spectrum showed no sharp diffraction peaks; the proton NMR spectrum measured with deuterated water showed characteristic absorption peaks at 1.615±0.1, 1.835±0.1, 3.127±0.1, 3.680±0.1, 3.853±0.1, 4.967±0.1, 6.249±0.1, 6.457±0.1, 7.244±0.1, 7.369±0.1, and 7.422±0.1 ppm.

[0015] In this invention, the baicalin / L-histidine co-amorphous compound was subjected to Cu-Kα radiation, and the powder X-ray diffraction spectrum showed no sharp diffraction peaks; the proton NMR spectrum measured with deuterated water showed characteristic absorption peaks at 3.226±0.1, 3.669±0.1, 3.854±0.1, 3.961±0.1, 4.949±0.1, 6.225±0.1, 6.427±0.1, 7.226±0.1, 7.396±0.1, and 8.360±0.1 ppm.

[0016] In this invention, the baicalin / 2-aminopyridine co-amorphous compound is subjected to Cu-Kα radiation, and the powder X-ray diffraction spectrum does not show sharp diffraction peaks; the proton NMR spectrum measured with deuterated water has characteristic absorption peaks at 3.684±0.1, 3.888±0.1, 3.910±0.1, 5.021±0.1, 6.338±0.1, 6.523±0.1, 6.766±0.1, 6.834±0.1, 6.855±0.1, 7.305±0.1, 7.419±0.1, 7.514±0.1, 7.532±0.1, 7.675±0.1, and 7.766±0.1 ppm.

[0017] In this invention, the molar ratio of baicalin to ligand is 1:0.1 to 10, preferably 1:0.2 to 5, and more preferably 1:0.5 to 1.5.

[0018] The present invention also provides a method for preparing the baicalin co-amorphous product, wherein baicalin and a ligand are reacted in a solvent, followed by solvent removal and drying to obtain the product;

[0019] The solvent contains water.

[0020] This invention innovatively demonstrates that using at least one of L-arginine, L-histidine, and 2-aminopyridine as a ligand unexpectedly provides structural compatibility with baicalin, facilitating the formation of a co-amorphous compound. Furthermore, by combining this innovative ligand compatibility with controlled solvent management during the preparation process, an unexpected synergistic effect can be achieved, promoting the formation of novel co-amorphous compound materials.

[0021] In this invention, the combination of the ligand and solvent is key to the successful preparation of the co-amorphous compound and to improving its solubility and bioavailability. Furthermore, controlling the ratio of baicalin and the ligand, as well as the processing temperature, can further improve the preparation effect and reduce costs.

[0022] Preferably, the molar ratio of baicalin to the ligand is 1:0.1 to 10, more preferably 1:0.2 to 5, and even more preferably 1:0.5 to 1.5;

[0023] Preferably, the solvent is water, or a mixture of water and an organic solvent, wherein the organic solvent is a solvent soluble in water, preferably at least one of C1 to C4 alcohols, acetone, and acetonitrile, and more preferably at least one of methanol, ethanol, and isopropanol.

[0024] Preferably, the water content in the solvent is 45% or more; in this invention, when the mixed solvent is used, the water content is preferably 45-60% (v).

[0025] In this invention, the amount of solvent can be adjusted as needed. For example, the volume-to-weight ratio of solvent to baicalin is above 5 ml / g, and considering cost, it can be further 10-250 ml / g, or even 10-80 ml / g.

[0026] Preferably, the reaction temperature is 20–65°C, more preferably 40–60°C;

[0027] Preferably, the reaction time is 1 to 10 hours, more preferably 1 to 8 hours, and even more preferably 4 to 8 hours;

[0028] Preferably, the solvent removal method is vacuum rotary evaporation;

[0029] Preferably, the temperature during the vacuum rotary evaporation stage is 30–65°C;

[0030] Preferably, the drying method is vacuum drying;

[0031] Preferably, after vacuum drying, the product is removed under an environment with a relative humidity of less than 30% RH to obtain the baicalin co-amorphous product.

[0032] This invention also provides the application of the aforementioned baicalin co-amorphous compound in the preparation of at least one drug with antibacterial and anti-inflammatory, antihypertensive, anti-allergic, antioxidant, anti-apoptotic, anti-tumor, cardiovascular and cerebrovascular disease treatment, immune enhancement, and liver protection properties.

[0033] In this invention, the baicalin co-amorphous compound, based on the combination of baicalin and its ligand, not only synergistically improves the effects of formulation such as dissolution and stability, but also synergistically improves bioavailability, further enhancing and improving the therapeutic effect of baicalin. That is, the baicalin co-amorphous compound of this invention can be used to treat any indication for which baicalin is effective.

[0034] The present invention also provides a pharmaceutical composition comprising a pharmaceutically effective amount of the baicalin coamorphous compound.

[0035] The pharmaceutical compositions of the present invention may also contain pharmaceutically acceptable excipients.

[0036] The pharmaceutical composition of the present invention has a pharmaceutically acceptable dosage form.

[0037] Beneficial effects

[0038] The co-amorphous form of baicalin provided in this invention has different powder X-ray spectra and proton nuclear magnetic resonance spectra from baicalin, L-arginine, L-histidine and 2-aminopyridine and their corresponding physical mixtures. Therefore, the solid form is a novel form that is completely different from the monomers and physical mixtures.

[0039] This invention prepares a co-amorphous compound from baicalin with L-arginine, L-histidine, and 2-aminopyridine. The compound exhibits good stability and advantages in solubility and dissolution. The co-amorphous compound formed by this invention improves the solubility of baicalin, and the pharmacological properties of the prepared co-amorphous compound enhance its applicability as a new solid product.

[0040] Furthermore, the baicalin co-amorphous compound described in this invention can also achieve synergistic adaptation in vivo, which helps to significantly improve bioavailability. Attached Figure Description

[0041] Figure 1 This is the X-ray powder diffraction (XRPD) pattern of baicalin.

[0042] Figure 2 XRPD diagram of L-arginine.

[0043] Figure 3 XRPD plot of L-histidine.

[0044] Figure 4 XRPD diagram of 2-aminopyridine.

[0045] Figure 5 XRPD diagram of the baicalin / L-arginine co-amorphous compound.

[0046] Figure 6 XRPD diagram of the baicalin / L-histidine co-amorphous compound.

[0047] Figure 7 This is the XRPD diagram of the amorphous compound of baicalin / 2-aminopyridine.

[0048] Figure 8 It is a co-amorphous product of baicalin / L-arginine. 1 H NMR spectrum.

[0049] Figure 9 A co-amorphous product of baicalin / L-histidine 1 H NMR spectrum.

[0050] Figure 10 It is a co-amorphous product of baicalin / 2-aminopyridine 1 H NMR spectrum.

[0051] Figure 11 The stability diagram of the baicalin / L-arginine co-amorphous compound is shown below: Figure 11 a is the high-temperature stability diagram at 60℃; Figure 11 b is 1.2 × 10 6 Lux×hr illumination stability diagram.

[0052] Figure 12 The stability diagram of the baicalin / L-histidine co-amorphous compound is shown below: Figure 12 a is the high-temperature stability diagram at 60℃; Figure 12 b is 1.2 × 10 6 Lux×hr illumination stability diagram.

[0053] Figure 13 The stability diagram of the baicalin / 2-aminopyridine co-amorphous compound is shown below: Figure 13 a is the high-temperature stability diagram at 60℃; Figure 13 b is 1.2 × 10 6 Lux×hr illumination stability diagram.

[0054] Figure 14 The figure shows the dissolution curves of baicalin co-amorphous compounds in purified water, where: Figure 14 a is the dissolution curve of the baicalin / L-arginine co-amorphous compound (where A: baicalin / L-arginine co-amorphous compound; B: baicalin raw material); Figure 14 b is the dissolution curve of the baicalin / L-histidine co-amorphous compound (where A: baicalin / L-histidine co-amorphous compound; B: baicalin raw material); Figure 14 c is the dissolution curve of the amorphous compound of baicalin / 2-aminopyridine (where A: amorphous compound of baicalin / 2-aminopyridine; B: baicalin raw material). Detailed Implementation

[0055] The instrument used in this invention for detecting co-amorphous drug structures is as follows:

[0056] X-ray powder diffractometer (XRPD), manufactured by Shimadzu Corporation of Japan, model XRD-6000X, Cu-K(α), tube voltage 40kV, tube current 40mA, scanning speed 2° / min.

[0057] A Varian Unity INOVA400 nuclear magnetic resonance spectrometer was used, with heavy water as the deuterated reagent and TMS as the internal standard for determination. 1 HNMR. 1 The observation frequency of the H NMR spectrum was 400 MHz. 1 The observed 10 kHz H NMR spectrum had a pulse angle of 30° and a pulse repetition time of 10 s. The test temperature was 40°C.

[0058] An Agilent 1260 Infinity high-performance liquid chromatograph was used, with a C18 column (4.6 mm × 250 mm, 5 μm). The mobile phase was methanol-water-phosphoric acid (47:53:0.2); the detection wavelength was 280 nm; the flow rate was 1 mL / min; the column temperature was 30 °C; and the injection volume was 20 μL.

[0059] Excess samples (baicalin, baicalin / L-arginine co-amorphous compound, baicalin / L-histidine co-amorphous compound, and baicalin / 2-aminopyridine co-amorphous compound) were added to 6 mL of purified water, and the resulting supersaturated solution was placed at 25 °C to test its equilibrium solubility.

[0060] Investigation of factors affecting sample light stability:

[0061] The samples (baicalin, baicalin / L-arginine co-amorphous compound, baicalin / L-histidine co-amorphous compound, and baicalin / 2-aminopyridine co-amorphous compound) were placed in weighing bottles, each no more than 2 mm thick, spread evenly, and placed under a D65 / ID65 emission standard light source, simultaneously exposed to a cool white fluorescent lamp and a near-ultraviolet lamp (spectral range: 320–400 nm, maximum emission energy 350–370 nm). The total illuminance was not less than 1.2 × 10⁶ Lux·hr, and the near-ultraviolet energy was not less than 200 W·hr / m². 2 Under these conditions, samples were taken on days 1, 3, 5, 10, and 15 to detect changes in baicalin content.

[0062] Investigation of factors affecting the high-temperature stability of samples:

[0063] The samples (baicalin, baicalin / L-arginine co-amorphous compound, baicalin / L-histidine co-amorphous compound, and baicalin / 2-aminopyridine co-amorphous compound) were placed in weighing bottles with a thickness not exceeding 2 mm and spread evenly. The changes in baicalin content were detected on days 1, 3, 5, 10, and 15 under the conditions of 60℃ and RH 75%.

[0064] Pharmacokinetics of baicalin in amorphous substances

[0065] Dosing regimen and sample collection

[0066] SD rats were randomly divided into three groups of six rats each. Before the experiment, the rats were fasted for 12 hours but allowed free access to water. They were administered baicalin at a dose of 120 mg / kg body weight via gavage in the following solutions: baicalin suspension prepared with 0.5% sodium carboxymethyl cellulose, baicalin / L-arginine co-amorphous aqueous solution, baicalin / L-histidine co-amorphous aqueous solution, and baicalin / 2-aminopyridine co-amorphous aqueous solution. Approximately 200 μL of blood was collected from the retro-orbital venous plexus at 0, 0.083, 0.167, 0.5, 1, 1.5, 2, 4, 6, 8, 10, 12, and 24 hours after administration. The blood samples were placed in heparinized centrifuge tubes, centrifuged at 10000 rpm for 5 minutes, and the supernatant plasma was collected and stored at -20°C.

[0067] Plasma sample processing

[0068] Take 100 μL of plasma, add 5 μL of luteolin internal standard solution (152 μg / mL) and 50 μL of 0.5 mol / L KH2PO4 solution (containing 1% sodium ascorbate), and vortex to mix. Add 150 μL of acetonitrile, vortex for 10 min, centrifuge at 10000 r / min for 10 min, and take the supernatant to obtain the processed plasma sample.

[0069] Example 1

[0070] Preparation of baicalin / L-arginine co-amorphous compound

[0071] Baicalin (200 mg, 0.448 mmol) and L-arginine (78 mg, 0.448 mmol) were weighed separately and placed in the same 25 mL round-bottom flask. 8 mL of purified water was added, and the mixture was stirred and sonicated at 60 °C until completely dissolved. The reaction was allowed to proceed for 4 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 60 °C. After complete evaporation, the corresponding solid products were obtained. These solid products were then dried in a vacuum drying oven at room temperature for 24 h to remove residual water. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0072] Example 2

[0073] Preparation of baicalin / L-arginine co-amorphous compound

[0074] Baicalin (1.0 g, 2.24 mmol) and L-arginine (78 mg, 0.448 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. A mixed solution of purified water and ethanol (V / V = 1 / 1) was added, and the mixture was stirred and sonicated at 40 °C until completely dissolved. The reaction was allowed to proceed for 8 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 60 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0075] Example 3

[0076] Preparation of baicalin / L-arginine co-amorphous compound

[0077] Baicalin (200 mg, 0.448 mmol) and L-arginine (390 mg, 2.24 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. A mixture of 40 mL purified water and isopropanol (V / V = 1 / 1) was added, and the mixture was stirred and sonicated at 40 °C until completely dissolved. The reaction was allowed to proceed for 6 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 55 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0078] The XRPD spectra of baicalin, L-arginine, and the co-amorphous product of baicalin / L-arginine are shown below. Figure 1 , 2 5. By Figure 5 It can be seen that the crystal diffraction peaks in the XRPD pattern of the baicalin / L-arginine co-amorphous compound all disappeared, and a single diffuse diffraction ring was obtained. Compared with the monomeric baicalin and L-arginine, the powder X-ray diffraction results of the co-amorphous compound are significantly different, indicating that the present invention has successfully prepared a new solid form.

[0079] Depend on Figure 8It can be seen that the 1H NMR spectrum of the baicalin / L-arginine co-amorphous compound measured with deuterated water has characteristic absorption peaks at 1.615, 1.835, 3.127, 3.680, 3.853, 4.967, 6.249, 6.457, 7.244, 7.369 and 7.422 ppm, and the chemical shifts of the above absorption peaks are significantly different from those of the monomers baicalin and L-arginine, indicating that it is a new solid product.

[0080] Depend on Figure 11 As can be seen from point a, the baicalin content of the amorphous compound of baicalin / L-arginine remained essentially unchanged after 15 days of continuous indoor light exposure, indicating its good photostability. Figure 11 As shown in b, the baicalin content of the amorphous compound of baicalin / L-arginine remained basically unchanged after 15 days of continuous high-temperature heating, indicating that it has good heat resistance stability.

[0081] Example 4

[0082] Preparation of baicalin / L-histidine co-amorphous compound

[0083] Baicalin (200 mg, 0.448 mmol) and L-histidine (70 mg, 0.451 mmol) were weighed separately and placed in the same 25 mL round-bottom flask. 6 mL of purified water was added, and the mixture was stirred and sonicated at 60 °C until completely dissolved. The reaction was allowed to proceed for 4 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 60 °C. After complete evaporation, the corresponding solid products were obtained. These solid products were then dried in a vacuum drying oven at room temperature for 24 h to remove residual water. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and less than 30% RH.

[0084] Example 5

[0085] Preparation of baicalin / L-histidine co-amorphous compound

[0086] Baicalin (1.0 g, 2.24 mmol) and L-histidine (70 mg, 0.451 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. 25 mL of a mixture of purified water and ethanol (V / V = 1 / 1) was added, and the mixture was stirred and sonicated at 50 °C until completely dissolved. The reaction was allowed to proceed for 6 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 60 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0087] Example 6

[0088] Preparation of baicalin / L-histidine co-amorphous compound

[0089] Baicalin (200 mg, 0.448 mmol) and L-histidine (350 mg, 2.26 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. A mixture of 35 mL of purified water and isopropanol (V / V = 1 / 1) was added, and the mixture was stirred and sonicated at 40 °C until completely dissolved. The reaction was allowed to proceed for 6 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 55 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was then dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0090] The XRPD spectra of baicalin, L-histidine, and the co-amorphous form of baicalin / L-histidine are shown below. Figure 1 , 3 6. By Figure 6 It can be seen that the crystal diffraction peaks in the XRPD pattern of the baicalin / L-histidine co-amorphous compound all disappeared, and a single diffuse diffraction ring was obtained. Compared with the monomeric baicalin and L-histidine, the powder X-ray diffraction results of the co-amorphous compound are significantly different, indicating that the present invention has successfully prepared a new solid form.

[0091] Depend on Figure 9 It can be seen that the 1H NMR spectrum of the baicalin / L-histidine co-amorphous compound measured with deuterated water has characteristic absorption peaks at 3.226, 3.669, 3.854, 3.961, 4.949, 6.225, 6.427, 7.226, 7.396 and 8.360 ppm, and the chemical shifts of the above absorption peaks are significantly different from those of the monomers baicalin and L-histidine, indicating that it is a new solid product.

[0092] Depend on Figure 12 As shown in Figure a, the baicalin / L-histidine co-amorphous compound exhibited essentially unchanged baicalin content after 15 days of continuous indoor light exposure, indicating good photostability. Figure 12 As shown in b, the baicalin content of the amorphous compound remained basically unchanged after 15 days of continuous high-temperature heating, indicating that it has good heat resistance.

[0093] Example 7

[0094] Preparation of baicalin / 2-aminopyridine co-amorphous compound

[0095] Baicalin (200 mg, 0.448 mmol) and 2-aminopyridine (42 mg, 0.446 mmol) were weighed separately and placed in the same 25 mL round-bottom flask. 5 mL of purified water was added, and the mixture was stirred and sonicated at 60 °C until completely dissolved. The reaction was allowed to proceed for 4 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 60 °C. After complete evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual water. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0096] Example 8

[0097] Preparation of baicalin / 2-aminopyridine co-amorphous compound

[0098] Baicalin (1.0 g, 2.24 mmol) and 2-aminopyridine (42 mg, 0.446 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. A mixture of 15 mL of purified water and ethanol (V / V = 1 / 1) was added, and the mixture was stirred and sonicated at 50 °C until completely dissolved. The reaction was allowed to proceed for 7 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 50 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0099] Example 9

[0100] Preparation of baicalin / 2-aminopyridine co-amorphous compound

[0101] 200 mg of baicalin (200 mg, 0.448 mmol) and 2-aminopyridine (210 mg, 2.23 mmol) were weighed separately and placed in the same 100 mL round-bottom flask. 35 mL of a mixture of purified water and isopropanol (V / V = 1 / 1) was added. The mixture was stirred and sonicated at 40 °C until completely dissolved. The reaction was allowed to proceed for 6 h to obtain a clear, transparent solution. This solution was then placed in a rotary evaporator under reduced pressure at a water bath temperature of 45 °C. After complete solvent evaporation, the corresponding solid product was obtained. This solid product was dried in a vacuum drying oven at room temperature for 24 h to remove residual solvent. The final product was then collected under a relative humidity of less than 30% RH and stored at 4 °C and a humidity of less than 30% RH.

[0102] The XRPD spectra of baicalin, 2-aminopyridine, and the co-amorphous form of baicalin / 2-aminopyridine are shown below. Figure 1 , 4 7. By Figure 7It can be seen that the crystal diffraction peaks in the XRPD pattern of the baicalin / 2-aminopyridine co-amorphous compound all disappeared, and a single diffuse diffraction ring was obtained. Compared with the monomeric baicalin and 2-aminopyridine, the powder X-ray diffraction results of the co-amorphous compound are significantly different, indicating that the present invention has successfully prepared a new solid form.

[0103] Depend on Figure 10 It can be seen that the 1H NMR spectrum of the amorphous compound of baicalin / 2-aminopyridine measured with deuterated water has characteristic absorption peaks at 3.684, 3.888, 3.910, 5.021, 6.338, 6.523, 6.766, 6.834, 6.855, 7.305, 7.419, 7.514, 7.532, 7.675 and 7.766 ppm. Moreover, the chemical shifts of the above absorption peaks are significantly different from those of the monomers baicalin and 2-aminopyridine, indicating that it is a new solid product.

[0104] Depend on Figure 13 As can be seen from point a, the baicalin content of the amorphous compound of baicalin / 2-aminopyridine remained essentially unchanged after 15 days of continuous indoor light exposure, indicating its good photostability. Figure 13 As shown in b, the baicalin content of the amorphous compound remained basically unchanged after 15 days of continuous high-temperature heating, indicating that it has good heat resistance stability.

[0105] Depend on Figure 14 It can be seen that the dissolution rates of the baicalin / L-arginine co-amorphous compound, the baicalin / L-histidine co-amorphous compound, and the baicalin / 2-aminopyridine co-amorphous compound are significantly improved compared to the raw material, and all of them can be completely dissolved in a very short time. This indicates that the baicalin co-amorphous compound prepared in this patent is easily soluble in water and has a good solubility advantage. In vivo pharmacokinetic studies (see Table 1) show that 24 hours after a single dose, compared with the baicalin suspension group, the peak plasma concentration of baicalin in the baicalin co-amorphous compound group (C0.05) is significantly higher. max Peak time (t) max Pharmacokinetic parameters such as baicalin and AUC showed significant changes (Table 2). The co-amorphous form of baicalin not only shortened the time to peak concentration of baicalin (t... max Peak plasma concentration (C) max The absorption rate of baicalin was increased by 2.8 to 3.5 times, and the area under the curve (AUC) increased by 2.5 to 3 times, significantly improving its bioavailability. This is mainly due to the formation of a co-amorphous structure by baicalin with L-arginine, L-histidine, and 2-aminopyridine, which improves the solubility and dissolution rate of baicalin, thereby enhancing its bioavailability.

[0106] Comparative Example 1

[0107] Compared with Example 1, the only difference is that the type and amount of ligand are changed, while other conditions remain the same as in Example 1. The experimental groups are as follows:

[0108] Group A: Ligand is L-glutamic acid;

[0109] Group B: Ligand is L-alanine;

[0110] Group C: Ligand is L-proline;

[0111] Group D: Ligand is L-threonine;

[0112] Group E: Ligand is L-valine;

[0113] XRPD analysis revealed that the characteristic diffraction peaks of the products in groups A, B, C, D, and E were all baicalin and their corresponding ligands, and no new substances were formed.

[0114] Comparative Example 2

[0115] Compared to Example 1, the only difference is that the solvent used in the reaction stage was changed, while the amount used and other conditions remained the same as in Example 1. The experimental groups were as follows:

[0116] Group A: Solvent: Acetonitrile;

[0117] Group B: Solvent: Acetone;

[0118] Group C: Solvent: Chloroform;

[0119] Group D: Solvent: Toluene;

[0120] Group E: Solvent: Diethyl ether;

[0121] XRPD analysis revealed that the characteristic diffraction peaks of the products in groups A, B, C, D, and E were all baicalin and their corresponding ligands, and no new substances were formed.

[0122] Table 1 Pharmacokinetic parameters of baicalin co-amorphous compounds

[0123] Baicalin suspension 1.50±0 7.95±1.64 69.87±7.95 Baicalin / L-arginine 1.00±0 23.67±1.38 219.44±0.56 Baicalin / L-histidine 0.90±0 27.82±0.61 237.51±3.77 Baicalin / 2-aminopyridine 0.85±0 29.39±2.42 259.13±1.03

[0124] Therefore, the present invention provides a novel co-amorphous compound of baicalin, which can significantly improve its dissolution behavior and, in addition, significantly improve its bioavailability.

Claims

1. A co-amorphous compound of baicalin, characterized in that, It is a co-amorphous compound formed by baicalin and a ligand, wherein the ligand is 2-aminopyridine; The baicalin / 2-aminopyridine co-amorphous compound exhibited no sharp diffraction peaks in its powder X-ray diffraction spectrum under Cu-Kα radiation. The proton NMR spectrum measured with deuterated water showed characteristic absorption peaks at 3.684±0.1, 3.888±0.1, 3.910±0.1, 5.021±0.1, 6.338±0.1, 6.523±0.1, 6.766±0.1, 6.834±0.1, 6.855±0.1, 7.305±0.1, 7.419±0.1, 7.514±0.1, 7.532±0.1, 7.675±0.1, and 7.766±0.1 ppm.

2. The baicalin co-amorphous compound as described in claim 1, characterized in that, The baicalin co-amorphous compound is a substance formed by baicalin and its ligands, which has no sharp diffraction peaks in its powder X-ray diffraction spectrum.

3. A method for preparing the baicalin co-amorphous compound according to any one of claims 1 to 2, characterized in that, Baicalin and its ligand are reacted in a solvent, followed by desolvation and drying to obtain the product. The solvent contains water.

4. The preparation method according to claim 3, characterized in that, The molar ratio of baicalin to ligand is 1:0.1~10.

5. The preparation method according to claim 4, characterized in that, The molar ratio of baicalin to ligand is 1:0.2~5.

6. The preparation method according to claim 5, characterized in that, The molar ratio of baicalin to ligand is 1:0.5~1.

5.

7. The preparation method according to claim 3, characterized in that, The solvent is water, or a mixture of water and an organic solvent, wherein the organic solvent is a solvent that is soluble in water.

8. The preparation method according to claim 7, characterized in that, The solvent is water, or a mixture of water and an organic solvent, wherein the organic solvent is at least one of C1-C4 alcohols, acetone, and acetonitrile. The solvent contains more than 45% water.

9. The preparation method according to claim 3, characterized in that, The reaction temperature is 20~65℃.

10. The preparation method according to claim 9, characterized in that, The reaction temperature is 40~60℃.

11. The preparation method according to claim 3, characterized in that, The reaction time is 1 to 10 hours.

12. The preparation method according to claim 3, characterized in that, The reaction time is 1 to 8 hours.

13. The preparation method according to claim 3, characterized in that, The reaction time is 4 to 8 hours.

14. The preparation method according to claim 3, characterized in that, The solvent removal method is vacuum rotary evaporation; The temperature during the vacuum rotary evaporation stage is 30~65℃.

15. The preparation method according to claim 3, characterized in that, The drying method is vacuum drying; After vacuum drying, the product was removed under a relative humidity of less than 30%RH to obtain the baicalin co-amorphous product.

16. The use of the baicalin co-amorphous compound according to any one of claims 1 to 2 or the baicalin co-amorphous compound prepared by the preparation method according to any one of claims 3 to 15 in the preparation of at least one drug with antibacterial, anti-inflammatory, antioxidant, anti-apoptotic, antitumor, cardiovascular and cerebrovascular disease treatment, immune enhancement, and liver protection effects.

17. A pharmaceutical composition, characterized in that, The amorphous form of baicalin as described in any one of claims 1 to 2, comprising a pharmaceutically effective amount, or the amorphous form of baicalin prepared by any one of claims 3 to 15.

18. The pharmaceutical composition of claim 17, characterized in that, It contains pharmaceutically acceptable excipients.

19. The pharmaceutical composition according to claim 17 or 18, characterized in that, It has a pharmaceutically acceptable dosage form.

Images