Luteolin pharmaceutical co-crystal as well as preparation method and application thereof

Abstract

The luteolin is low in bioavailability, and the luteolin is the same as metformin and has a wide effect but a weak effect, so that the clinical application of the luteolin and the metformin (except for reducing blood sugar) is limited. In order to improve the problem, the luteolin and metformin eutectic crystal is prepared in the invention. X-single crystal diffraction and FT-IR (Fourier transform infrared spectroscopy) show that luteolin and metformin are coupled into three-dimensional supramolecular lamellar crystals according to a molar ratio of 1: 1 through hydrogen bonds, DSC (differential scanning calorimetry) shows that the melting point of the three-dimensional supramolecular lamellar crystals is remarkably reduced, and DVS (differential scanning spectroscopy) shows that the three-dimensional supramolecular lamellar crystals have good wettability; compared with luteolin, the dissolution rate of the eutectic crystal is increased by more than 7 times, and the biological bioavailability is increased by more than 10 times; anticancer activity shows that luteolin and metformin have an obvious synergistic effect, and a ester reduction experiment shows that the eutectic crystal obviously improves oleic acid induced HepG2 cell lipid droplet accumulation. According to the invention, triple improvement of solubility, bioavailability and pharmacological activity is realized through co-crystallization, and an innovative solution is provided for clinical application of luteolin and development of metformin non-hypoglycemic indications.

Description

Technical Field

[0001] The invention belongs to the technical field of organic drug co-crystals and relates to luteolin co-crystals and a preparation method and application thereof. Background Art

[0002] Luteolin (Lut) is chemically named 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4H-benzopyran-4-one and belongs to the flavonoid class of drugs. Its structural formula is shown in Formula 1. Metformin (Met) is chemically named 1,1-dimethylbiguanidine and its structural formula is shown in Formula 2.

[0003]

[0004] Luteolin is a natural product found in various traditional Chinese medicines. Like metformin, it possesses multiple pharmacological effects, including antioxidant, anti-inflammatory, and anti-tumor properties, as well as therapeutic effects for hepatitis, asthma, neuroinflammation, and sclerosis. However, luteolin's extremely low solubility results in low bioavailability (6 mg / L), and its pharmacological effects are weak, preventing its commercialization and clinical application in any country. This low pharmacological effect is a major reason why metformin hydrochloride, aside from its diabetes treatment, has so far remained a drug. Summary of the Invention

[0005] The present invention aims to address at least one of the aforementioned problems in the prior art. To this end, the first objective of the present invention is to provide a luteolin-metformin cocrystal that improves the drug's physicochemical properties, such as dissolution and bioavailability, and its weak efficacy.

[0006] The second object of the present invention is to provide a method for preparing the above-mentioned luteolin-metformin cocrystal.

[0007] The third object of the present invention is to provide a pharmaceutical composition comprising the luteolin-metformin co-crystal, wherein the pharmaceutical composition is administered orally or by injection.

[0008] The fourth object of the present invention is to provide the use of the above-mentioned luteolin-metformin cocrystal and a pharmaceutical composition comprising luteolin-metformin.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] The luteolin-metformin cocrystal provided by the present invention uses luteolin and metformin as active molecules, coupled at a molar ratio of 1:1 through hydrogen bonding and / or van der Waals forces to form a three-dimensional supramolecular crystal, wherein:

[0011] The luteolin-metformin cocrystal belongs to the monoclinic system, and its space group is P21 / n. and α=90°, β=98.215(4)°, γ=90°, =2287.39(16)Z=4, molecular formula is C 19 H 21 N5O 6， The molecular weight is 415.41, and the final reliability factors of the observed reflections of all data obtained during the refinement process are R1=0.0583 (I>2σ(I)) and wR2=0.1694.

[0012] The intermolecular hydrogen bond on the luteolin-metformin cocrystal is: N4-H4B···O2, ∠NH···O=149.57(13)°. Intramolecular hydrogen bond: O1-H1···O5, ∠OH···O=164.34(11)°. Interlayer hydrogen bond: O2-H2···O3, ∠OH···O=145.57(12)° and O6-H6···O3, ∠OH···O=137.89(13)°. All hydrogen bond donors and acceptors of luteolin form intermolecular or intramolecular hydrogen bonds with metformin or luteolin itself. Furthermore, this three-dimensional hydrogen bonding contributes to the lamellar stacking of luteolin molecules, rationalizing the observed plate-like cocrystal morphology.

[0013] Preferably, Hirshfeld Surface analysis of luteolin-metformin cocrystal showed that OH···O interaction was the most significant intermolecular force, accounting for d norm The surface area accounts for 28.4%, and the H···H interaction force accounts for 38.0%, which is mainly represented by van der Waals forces.

[0014] Preferably, the X-ray diffraction pattern of the luteolin-metformin cocrystal is marked with a diffraction angle 2θ, and has characteristic diffraction peaks at 7.6287, 8.2005, 12.7954, 16.4190 and 24.7013 respectively.

[0015] Preferably, the melting point of the luteolin-metformin cocrystal is 141-144.5°C, and the differential scanning calorimetry curve has a characteristic peak at 143.894°C. Under the same conditions, the differential scanning calorimetry curve of luteolin has a characteristic peak at 333.5°C, and the differential scanning calorimetry curve of metformin has characteristic peaks at 80.8°C, 121.9°C, and 294.1°C.

[0016] Preferably, the infrared absorption spectrum of the luteolin-metformin cocrystal is at 3344.56 cm -1 、3132.16cm -1 、1684.12cm -1 There is an absorption peak at.

[0017] Preferably, the luteolin-metformin cocrystal has a hygroscopicity of 6.5% under a relative humidity (RH) of 80%, and the hygroscopicity of luteolin under the same conditions is 1.5%.

[0018] Preferably, the solubility of the luteolin-metformin cocrystal in the dissolution medium of 0.2% sodium dodecyl sulfate and 30% ethanol is 57.68% and 33.90%, respectively. Under the same conditions, the solubility of luteolin is 7.59% and 7.05%.

[0019] The present invention provides a method for preparing the above-mentioned luteolin-metformin cocrystal, comprising the following steps:

[0020] (1) Dissolution: Add luteolin and metformin to a solvent, wherein the metformin is a free base or a salt that can be converted into a free base, wherein the molar ratio of luteolin to metformin is 1:1-10, and dissolve by heating or ultrasonication at a dissolution temperature of 20-80°C.

[0021] (2) Crystallization: Crystallization is performed by cooling or solvent evaporation, and the precipitated solid is luteolin-metformin cocrystal.

[0022] In the step (1), the solvent is selected from one or a combination of two or more of water, methanol, ethanol, isopropanol, tetrahydrofuran, acetone, ethyl acetate, and acetonitrile.

[0023] In the above-mentioned step (2), cooling or solvent evaporation crystallization is adopted, and stirring or ultrasound can be used.

[0024] As a preferred technical solution, the preparation method of the luteolin-metformin cocrystal comprises: adding luteolin and metformin free base in an equal molar ratio (1:1) to anhydrous ethanol, stirring to dissolve, rapidly filtering, distilling off 0-2 / 3 of the solvent, and yellow crystals precipitating after 0-96 hours, filtering to obtain the cocrystal.

[0025] As a preferred technical solution, the preparation method of the luteolin-metformin cocrystal further comprises: adding luteolin and metformin free base in an equimolar ratio (1:1) to tetrahydrofuran, ultrasonically treating for 0-2 hours, and filtering to obtain the cocrystal.

[0026] As a preferred technical solution, the single crystal preparation method of the luteolin metformin cocrystal is as follows: luteolin (1.14 g, 4 mmol) is added to 55 ml of ethanol, heated under reflux for 1 hour, then cooled to 50°C, metformin free base (0.47 g, 3.6 mmol) is added and reacted for 30 minutes, filtered, and metformin free base (0.052 g, 0.4 mmol) is added to the filtrate, stirred for 30 minutes, and after distilling about 20 to 35 ml of the solvent, it is placed in a refrigerator at 4°C and stored away from light. Yellow flaky transparent crystals precipitate, which are luteolin metformin single crystals.

[0027] The present invention provides a pharmaceutical composition comprising luteolin-metformin cocrystal and a pharmaceutically acceptable carrier.

[0028] As a preferred technical solution, the pharmaceutical composition is administered orally or by injection.

[0029] The present invention provides the use of the luteolin-metformin cocrystal and the composition containing the luteolin-metformin cocrystal in the prevention and treatment of cancer, fatty liver, diabetes, hepatitis, asthma, neuroinflammation, and sclerosis.

[0030] Preferably, the maximum blood concentration (C max ) was 786.6 ng / mL, the peak area under the drug-dose curve (AUC 0-t ) was 1794.65±152.72ng·h / mL. Under the same conditions, the C max =75.77ng / mL, AUC 0-t It is 23.45±28.23ng·h / mL.

[0031] Preferably, the IC50 of the luteolin-metformin cocrystal for different cancer cells is 97.85 μM (HepG2), 143.9 μM (A549), and 137.3 μM (HeLa). Under the same conditions, the IC50 of metformin is 18.88 mM (HepG2), 27.60 mM (A549), and 14.95 mM (HeLa); the IC50 of luteolin is 353.2 μM (HepG2), 288.4 μM (A549), and 423.9 μM (HeLa); the IC50 of the physical mixture of luteolin and metformin is 246.3 μM (HepG2), 289.2 μM (A549), and 424.2 μM (HeLa).

[0032] Preferably, the luteolin-metformin cocrystal is incubated with oleic acid-induced HepG2 cells, and within 24 hours, the lipid droplets are significantly decreased compared with the normal group.

[0033] Compared with the prior art, the present invention has the following advantages:

[0034] (1) In the present invention, luteolin forms a cocrystal with metformin, which greatly improves the hygroscopicity, solubility and dissolution rate of luteolin, thereby greatly increasing the bioavailability of luteolin.

[0035] (2) The present invention provides luteolin-metformin cocrystals, which can exert a multi-target synergistic effect and effectively reduce the cancer cell ablation concentrations of luteolin alone, metformin, and the physical mixture of luteolin and metformin.

[0036] (3) The present invention provides a luteolin-metformin cocrystal, which, through multi-target synergy, can overcome the shortcomings of luteolin's broad pharmacological activity and weak individual pharmacological activity, making luteolin and metformin (in addition to lowering blood sugar) drugable. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the crystal structure diagram of the luteolin-metformin cocrystal in Example 4;

[0038] Figure 2 is the hydrogen bonding diagram of the luteolin-metformin cocrystal in Example 4 (axes ab);

[0039] Figure 3 is a two-dimensional structure diagram of the luteolin-metformin cocrystal in Example 4 (ac axis);

[0040] Figure 4 This is the three-dimensional structure of the luteolin-metformin cocrystal in Example 4

[0041] Figure 5 This is a diagram showing the appearance of the luteolin-metformin cocrystal in Example 4;

[0042] Figure 6 This is the Hirshfeld surface analysis diagram of the luteolin-metformin cocrystal in Example 5.

[0043] Figure 7 is the X-ray powder diffraction pattern of luteolin-metformin cocrystal, luteolin and metformin in Example 6;

[0044] Figure 8 is the DSC graph of luteolin-metformin cocrystal, luteolin and metformin in Example 7;

[0045] Figure 9 FT-IR images of the luteolin-metformin cocrystal, luteolin, metformin, and the luteolin-metformin physical mixture in Example 8;

[0046] Figure 10is a DVS diagram of luteolin-metformin cocrystal and luteolin in Example 9;

[0047] Figure 11 is a dissolution curve of luteolin-metformin cocrystal and luteolin in 0.2% SDS in Example 10;

[0048] Figure 12 is a dissolution curve of luteolin-metformin cocrystal and luteolin in 30% ethanol in Example 10;

[0049] Figure 13 Graphs showing the concentration and cell viability of luteolin-metformin cocrystal, luteolin, metformin, and the physical mixture of luteolin-metformin in HepG2, A549, Hela, HT29, and normal NCM460 cells in Example 11;

[0050] Figure 14 This is a comparison chart of the lipid droplet reduction in HepG2 cells by luteolin-metformin cocrystal, luteolin, metformin and the physical mixture in Example 12.

[0051] Figure 15 This is a comparison diagram of the concentration-time curves of luteolin-metformin cocrystal and luteolin in Example 13; DETAILED DESCRIPTION

[0052] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings. It should be noted that these embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Those skilled in the art may make non-essential adjustments and modifications based on the above-mentioned invention, and such adjustments and modifications will also fall within the scope defined by the appended claims.

[0053] Real-time Example 1

[0054] Preparation of metformin free base: Take sodium hydroxide (2.00 g, 50 mmol), add 250 ml of anhydrous ethanol, stir, add metformin hydrochloride (8.28 g, 50 mmol), stir at room temperature for 3 hours, then filter, and the filtrate is dried under reduced pressure at 40°C to obtain metformin free base solid, which is used for the next reaction.

[0055] Preparation of luteolin-metformin cocrystals: Add luteolin (2.86 g, 10 mmol) and metformin free base (1.29 g, 10 mmol) to a round-bottom flask, add 60 ml of anhydrous ethanol, heat to 50°C and stir for 30 min, cool to room temperature, and yellow crystals will precipitate. Filter and dry to obtain luteolin-metformin cocrystals with a melting point (mp): 141-143°C.

[0056] Real-time Example 2

[0057] Luteolin (2.86 g, 10 mmol) and metformin free base (1.29 g, 10 mmol) were added to a round-bottom flask, and 30 ml of tetrahydrofuran was added. The mixture was ultrasonicated at 40°C for 40 minutes, filtered, and dried to obtain luteolin-metformin cocrystals with mp: 142-144°C.

[0058] Real-time Example 3

[0059] Luteolin (1.14 g, 4 mmol) was added to 55 ml of ethanol, heated under reflux for 1 hour, then cooled to 50°C, metformin free base (0.47 g, 3.6 mmol) was added and reacted for 30 minutes, filtered, and metformin free base (0.052 g, 0.4 mmol) was added to the filtrate. The mixture was stirred for 30 minutes. After distilling about 25 ml of the solvent, the mixture was stored in a refrigerator at 4°C away from light. Yellow flaky transparent crystals precipitated, which were luteolin metformin single crystals, each batch: 143.5-144.5°C.

[0060] Example 4

[0061] The single crystal of Example 3 was taken and the structure was analyzed and modified using a Bruker Smart Apex II X-ray single crystal diffractometer and SHELXL-97. The structure diagram was obtained using Diamond software. The results showed that the basic structural unit of the luteolin-metformin cocrystal is composed of one luteolin and one metformin molecule, with a monoclinic crystal system and space group P21 / n. and α=90°, β=98.215(4)°, γ=90°, Z=4,the molecular formula is C 19 H 21 N5O6, its crystallographic parameters are shown in Table 1. Figure 1 It was shown that the luteolin and metformin molecules in the asymmetric unit were arranged in an orderly 1:1 ratio through intermolecular forces to form the basic unit of the crystal. Figure 2 , Figure 3 As shown in Table 2, the hydrogen bond between luteolin and metformin molecules is [N4-H4B···O2]( The bond angle is 149.57°) as the structural skeleton drives the molecules to stack alternately along the b axis. The intramolecular hydrogen bonds of luteolin [O1-H1···O5]( The bond angle is 164.34°) which stabilizes the molecular planar configuration by reducing the conformational entropy. The interlayer hydrogen bond network [O2-H2···O3]( bond angle 145.57°) and [O6-H6···O3]( The bond angle is 137.89°) together to form an ac plane layered arrangement. Figure 4It is further shown that the face-to-face π-π stacking of aromatic rings and the synergistic effect of van der Waals forces enhance the interlayer cohesion, which is manifested in the macroscopic lamellar morphology of the crystal ( Figure 5 ).

[0062] Table 1 Crystallographic parameters of luteolin-metformin cocrystal

[0063]

[0064]

[0065] Table 2 The order and mode of hydrogen bonding in luteolin-metformin cocrystals

[0066]

[0067] Symmetry transformations used to generate equivalent atoms: 1 1-x, 1-y, 1-z

[0068] Example 5

[0069] CrystalExplorer v17.5 software was used to perform Hirshfeld Surface analysis of luteolin-metformin cocrystals. Figure 6 As shown, norm The parameter-mapped 3D surface shows a unique molecular contact pattern: the red area (d norm Negative values) correspond to shortened intermolecular contacts, and their spatial distribution range and chromatic intensity directly reflect the strength of hydrogen bonding. In this system, OH···O interactions account for d norm The significant proportion of 28.4% of the surface becomes the dominant intermolecular force, and this characteristic value can be regarded as a typical sign of strong directional interaction. In contrast, the diffuse blue-green area (d norm Positive values indicate extended contacts. H···H interactions dominate, accounting for 38.0%, primarily reflecting van der Waals forces, the key non-covalent interactions driving supramolecular construction. The synergistic effect of strong hydrogen bonds and weak van der Waals forces forms the structural foundation of eutectic supramolecular systems, with directional hydrogen bonds determining the molecular arrangement pattern, while isotropic van der Waals forces provide space-filling support.

[0070] Example 6

[0071] like Figure 7As shown, the luteolin-metformin cocrystal exhibits unique crystallographic characteristics that are clearly distinguishable from the parent compounds luteolin and metformin. The diffraction pattern of the luteolin-metformin cocrystal exhibits new characteristic Bragg reflection peaks with 2θ angles of 7.6287°, 8.2005°, 12.7954°, 16.4190°, and 24.7013°, respectively. Concomitantly, the characteristic peaks of the parent compounds (luteolin: 10.3211°, 12.5075°, 20.6987°, 23.9833°, 24.5267°; metformin: 12.7831°, 14.0801°, 14.2345°, 15.8863°, 25.4752°) completely disappear. The appearance of the new Bragg reflection peak and the complete disappearance of the characteristic peaks of the parent compound both indicate that long-range crystallographic reconstruction occurred during the co-crystallization process, excluding the possibility of physical mixing.

[0072] Real-time Example 7

[0073] like Figure 8 As shown in the figure, the DSC thermal analysis curve of the luteolin-metformin cocrystal shows a characteristic sharp endothermic peak at 143.894°C, corresponding to the melting process of the luteolin-metformin cocrystal. This temperature is significantly different from that of the single components quercetin (333.5°C) and metformin (80.8°C, 121.9°C, 294.1°C). Compared with luteolin, the melting point of the cocrystal is reduced by 189.6°C, indicating that the molecular stacking of luteolin in the cocrystal is optimized, which indicates that the solubility of luteolin may be significantly improved.

[0074] Example 8

[0075] Figure 9 The infrared spectra of luteolin, metformin, a physical mixture of luteolin and metformin, and a luteolin and metformin cocrystal show that the NH stretching vibration peak (3366.52 cm-1) and -NH deformation vibration peak (3147.65 cm-1) in metformin are red-shifted to 3344.56 cm-1 and 3132.16 cm-1, respectively, in the cocrystal, confirming that the amino group of metformin participates in the construction of the hydrogen bond network. The luteolin and metformin cocrystal exhibits a characteristic absorption peak at 1648.12 cm-1, which is 26.58 cm-1 blue-shifted compared to the bending vibration peak of the aliphatic primary amine in metformin (1621.54 cm-1). In addition, the broad OH stretching band of luteolin in the cocrystal spectrum (3083 cm-1, originating from the intramolecular C=O···HO-Ar hydrogen bond) disappeared, and no free phenolic hydroxyl OH stretching signal was detected (non-bonded -OH was 3700-3584 cm-1), indicating that the phenolic hydroxyl group of luteolin participated in the construction of intermolecular hydrogen bonds.

[0076] Real-time Example 9

[0077] The hygroscopicity and hydration kinetics of luteolin-metformin cocrystals and luteolin were evaluated by dynamic vapor sorption (DVS) technique. Figure 10 As shown in the figure, luteolin only gained 1.5% weight at 80% RH, indicating its poor hydrophilicity and wettability; while luteolin-metformin cocrystal gained 6.5% weight under the same conditions, and its hygroscopicity was 4.3 times higher than that of luteolin.

[0078] Real-time Example 10

[0079] The dissolution behavior of luteolin-metformin cocrystal and luteolin in 0.2% sodium dodecyl sulfate solution (SDS) and 30% ethanol water was compared using a dissolution tester. Figure 11 and 12 The solubility of luteolin-metformin cocrystals and luteolin in both media reached a dissolution plateau at approximately 40 minutes. The solubility of luteolin-metformin cocrystals in 0.2% SDS aqueous solution reached 57.68%, and in 30% ethanol water was 33.90%, representing increases of 7.6 times and 4.8 times, respectively, compared to luteolin in 0.2% SDS aqueous solution (7.59%) and 30% ethanol solution (7.05%). This effectively avoids the problem of low bioavailability of luteolin due to insufficient solubility.

[0080] Real-time Example 11

[0081] Through a comparative study of CCK-8 experiments, the multi-target synergistic anti-tumor effects of luteolin-metformin cocrystals were systematically evaluated. The study analyzed the concentration-dependent inhibitory effects of luteolin, metformin hydrochloride, luteolin-metformin cocrystals, and a physical mixture of luteolin and metformin on four cancer cell lines, A549, HepG2, HeLa, and HT-29, and normal cells NCM460 after incubation for 24 hours. Figure 13As shown in Table 3, metformin hydrochloride exhibited no significant cytotoxicity against all cancer cell lines within the tested concentration range of luteolin-metformin cocrystal (0-320 μM), with IC50 values of 27.60 mM (A549), 18.88 mM (HepG2), 14.95 mM (HeLa), and 35.39 mM (HT-29), respectively. Furthermore, luteolin and its physical mixture of luteolin and metformin exhibited similar inhibitory effects on A549 and HeLa cells, with IC50 values of 289 μM (Lut) and 423 μM (Lut / Met), respectively. In HepG2 cells, the inhibitory effect of the physical mixture of luteolin and metformin (IC50: 246.3 μM) was slightly superior to that of luteolin alone (IC50: 353.2 μM), suggesting a possible synergistic effect. Luteolin-metformin cocrystals exhibited significant multi-target synergistic advantages in A549, HepG2, and Hela cells: compared with luteolin alone, their IC50 values were reduced by 49.9% (143.9μM vs 288.4μM), 72.3% (97.85μM vs 353.2μM), and 67.6% (137.3μM vs 423.9μM), respectively, significantly outperforming the physical mixture. In HT29 cells, the inhibitory activity of luteolin-metformin cocrystals (IC50: 577.3μM) and luteolin alone (IC50: 628.4μM) was weak, indicating that the anti-tumor response was tumor-specific. Notably, all tested compounds exhibited significantly higher IC50 values against normal NCM460 cells than against cancer cells (luteolin-metformin cocrystal: 688.5 μM; luteolin: 444.8 μM; metformin hydrochloride: 338.6 mM; luteolin-metformin physical mixture: 502.6 μM), demonstrating the therapeutic selectivity of the cocrystal. This study confirms that luteolin-metformin cocrystals can synergistically enhance anti-tumor efficacy through multiple targets.

[0082] Table 3 IC50 values of luteolin-metformin cocrystals and their monomers and physical mixtures

[0083] HepG2 A549 HeLa HT-29 NCM460 Lut-Met / uM 97.85 143.9 137.3 577.3 688.5 Lut / uM 353.2 288.4 423.9 628.4 444.8 Met / mM 18.88 27.60 14.95 35.39 338.6 Lut / Met / uM 246.3 289.2 424.2 1530 502.6

[0084] Example 12

[0085] HepG2 cells were incubated with oleic acid for 12 hours, and then the excess oleic acid was washed away with PBS. Then, culture medium containing 50 μM luteolin-metformin cocrystal, luteolin, metformin hydrochloride, and a physical mixture of luteolin-metformin were added and incubated for 24 hours. At the same time, blank control was used. The cells were then stained with Nile red for 10 minutes, excited with yellow light, and imaged in the wavelength range of 610-660 nm. The fluorescence intensity of each group was compared with that of the blank group. The results are shown in the figure. Figure 14The results showed that the fluorescence intensity of the physical mixture group of metformin and luteolin-metformin was slightly lower than that of the blank group. In contrast, the fluorescence intensity of the luteolin-metformin cocrystal group was significantly lower than that of the blank group, indicating that luteolin-metformin cocrystal has a strong effect in reducing fat in the liver; luteolin alone has a weak effect in reducing lipid droplets in HepG2 cells.

[0086] Example 13

[0087] A comparative pharmacokinetic study of luteolin and its cocrystal was conducted in SD rats. Figure 15 As shown in Table 4, the luteolin and metformin cocrystal exhibited significantly improved pharmacokinetic characteristics compared to luteolin. As shown in Table 4, the luteolin reached its peak blood concentration (C max =75.77ng / mL, T max =15min), and then enters the elimination phase (elimination half-life t / =1.25 hours); while the C max Reached 786.6ng / mL (10.3 times higher than luteolin), T max The elimination half-life of luteolin-metformin cocrystal was extended to 30 minutes, indicating improved absorption characteristics. Although the elimination half-life of luteolin-metformin cocrystal was slightly shorter (t / =1.0h), a high blood concentration was maintained during the 25-hour observation period. Pharmacokinetic analysis showed that the AUC of luteolin-metformin cocrystal was 0-t (1794.65±152.72ng·h / mL) was 8.03 times higher than that of luteolin (23.45±28.23ng·h / mL), confirming the feasibility of luteolin-metformin cocrystal in improving oral bioavailability and achieving multi-target therapy.

[0088] Table 4. Pharmacokinetic parameters of luteolin and its cocrystals

[0089] parameter Luteolin Luteolin and Metformin Cocrystal <![CDATA[T max (h)]]> 0.25 0.5 <![CDATA[C max (ng·ml-1)]]> 75.77±52.62 786.62±109.44 <![CDATA[AUC 0-t (ng·h·ml-1)]]> 223.45±28.23 1794.65±152.72 <![CDATA[T 1 / 2 (h)]]> 1.25 1

Claims

1. Luteolin-metformin cocrystal is a three-dimensional supramolecular crystal formed by coupling luteolin and metformin through hydrogen bonds and / or van der Waals interactions.

2. The luteolin-metformin cocrystal according to claim 1, characterized in that The structural formula of the basic structural unit is:

3. The luteolin-metformin cocrystal according to claim 1, characterized in that The basic structural unit of the luteolin-metformin cocrystal is composed of a luteolin molecule and a metformin free base molecule, with a monoclinic crystal system and a space group of P21 / n. And α=90°, β=98.215(4)°, γ=90°, Z=4. Z=4,the molecular formula is C 19 H 21 N5O6.

4. The luteolin-metformin cocrystal according to claim 1, characterized in that The X-ray diffraction pattern of the luteolin-metformin cocrystal is marked with a diffraction angle 2θ, and has characteristic diffraction peaks at 7.6287, 8.2005, 12.7954, 16.4190 and 24.7013.

5. The luteolin-metformin cocrystal according to claim 1, characterized in that The differential scanning calorimetry curve of the luteolin-metformin cocrystal has a characteristic peak at 143.894±3°C.

6. The method for preparing the luteolin-metformin cocrystal according to claims 1 to 5, characterized in that: Contains the following steps (1) Dissolution: Add luteolin and metformin to a solvent, wherein the metformin is a free base or a salt that can be converted into a free base, wherein the molar ratio of luteolin to metformin is 1:1-10, and dissolve by heating or ultrasonication at a dissolution temperature of 20-80°C. (2) Crystallization: Crystallization is performed by cooling and / or solvent evaporation, and the precipitated solid is luteolin-metformin cocrystal.

7. The method for preparing luteolin-metformin cocrystal according to claim 6, characterized in that: The solvent in step (1) is selected from one or a combination of two or more of water, methanol, ethanol, isopropanol, n-propanol, tetrahydrofuran, acetone, ethyl acetate, and acetonitrile; The cooling in step (2) is performed at room temperature or by standing and crystallizing under cooling or by crystallizing under solvent evaporation.

8. The method for preparing luteolin-metformin cocrystal according to claim 6, characterized in that: The method for preparing the luteolin-metformin cocrystal comprises: adding luteolin and metformin free base in a molar ratio of 1:1 to a solvent, performing ultrasonication or stirring for a period of time, then cooling or crystallizing at room temperature, and precipitating yellow crystals after 0-96 hours.

9. A pharmaceutical composition, characterized in that The pharmaceutical composition comprises the luteolin-metformin cocrystal according to claims 1 to 5 and a pharmaceutically acceptable carrier; the pharmaceutical composition is administered orally or by injection.

10. Use of the luteolin-metformin cocrystal according to claims 1 to 5 or the pharmaceutical composition according to claim 9 in preventing and treating diseases such as cancer, hepatitis, fatty liver, diabetes, neuroinflammation, asthma, and sclerosis.

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