High-molecular microspheres for improving solubility of silymarin

Abstract

The application aims to establish a solubilization system for improving the dissolution of silymarin and prepare silymarin-loaded polymer microspheres, and belongs to the technical field of pharmaceutical preparations. The silymarin polymer microspheres prepared by the solubilization system can significantly improve the dissolution of silymarin. The method for preparing the silymarin polymer microspheres in the application is as follows: S1: uniformly mixing pre-activated corn starch, nicotinamide and O / W emulsifier in deionized water to form an aqueous phase; S2: dissolving silymarin in ethyl acetate to form an oil phase; S3: slowly adding the oil phase to the aqueous phase and stirring at high speed to prepare an emulsion; S4: placing the emulsion in an ice water bath for several hours, centrifuging, taking the precipitate, and freeze-drying to obtain silymarin microspheres.

Description

Technical Field

[0001] The purpose of this invention is to establish a solubilizing system for improving the solubility of silymarin and to prepare silymarin-loaded polymeric microspheres, belonging to the field of pharmaceutical formulation technology. The silymarin polymeric microspheres prepared by this solubilizing system can significantly improve the solubility of silymarin. Background Technology

[0002] Silymarin is a flavonoid compound extracted from the fruit of the milk thistle (Silybum marianum L. Gaertn), a plant in the Asteraceae family. Its main components include silybin, silymarinine, and silymarinine ethinylene. Silymarin is soluble in acetone, ethyl acetate, ethanol, and methanol; slightly soluble in chloroform; and insoluble in water. Silymarin is one of the main hepatoprotective drugs used clinically to treat acute and chronic hepatitis, metastatic hepatitis, cirrhosis, fatty liver, various liver injuries, and pain associated with cholecystitis, pericholecystitis, and cholelithiasis. Modern research has also found that slymarin can be used to treat hyperlipidemia and complications of diabetes. However, the near insolubility of slymarin in water affects the dissolution of the active ingredient in drug formulations, resulting in poor absorption and low bioavailability. Therefore, we have developed a solubilization system to improve the solubility of slymarin.

[0003] Statistics show that 40% of globally marketed drugs are poorly soluble, and the proportion of poorly soluble drug candidates in the research and development stage is as high as 90%. Drug dissolution has become one of the major challenges restricting new drug development. Therefore, increasing drug solubility and dissolution rate, thereby improving its bioavailability in the body, has become one of the most active research directions in the field of pharmaceutics. Currently, there are many reports on drug solubilization research both domestically and internationally, including solid dispersions, micronization, cyclodextrin inclusion complexes, nanosuspensions, self-microemulsion technology, and phospholipid complexes.

[0004] Starch, due to its low cost and easy availability, has become a renewable industrial raw material, widely used in food, textiles, and medicine. Starch is a glucosinolate formed by the dehydration polymerization of multiple glucose molecules through hydroxyl groups. Containing a large number of hydroxyl groups, it has good hydrophilicity. However, starch is not soluble in water because the hydroxyl groups in starch exist in a hydrogen-bonded state, resulting in strong intermolecular aggregation forces that prevent water molecules from penetrating the starch granules and solubilizing them. Therefore, to improve the solubility of starch, it is necessary to break these strong intermolecular aggregation forces. Acid hydrolysis, alkaline hydrolysis, and pressure hydrolysis of starch can reduce the degree of polymerization of starch molecules, thereby improving starch solubility. Enzymatic treatment of starch can achieve the same effect. Currently, starch hydrolytic enzymes widely used in the starch industry mainly include α-amylase, β-amylase, glucoamylase, and debranching enzymes. Different types of amylases act on starch (including amylose and amylopectin) in different ways, exhibiting high specificity for catalytic hydrolysis of starch or the catalytic conversion of various starch hydrolysates.

[0005] Common methods for preparing microspheres include emulsification solvent evaporation, seed swelling, phase separation, and spray drying. Emulsification solvent evaporation can be further divided into O / W solvent evaporation and bilayer emulsification solvent evaporation methods, depending on the emulsification process. In the O / W solvent evaporation method, the material is dissolved in a volatile organic solvent (such as chloroform or dichloromethane), and this solution is added to an aqueous solution containing an emulsifier. After stirring and emulsification, the solvent evaporates to obtain microspheres. Seed swelling can be used to produce monodisperse porous polymer microspheres, resulting in larger particles with high cross-linking and relatively uniform pores. The principle of phase separation is that the oil-based dispersion medium and the polymer undergo phase separation during the evaporation of the organic solvent. After washing away the oil-based medium, the microspheres obtain a porous structure. Porous microspheres prepared by phase separation have a uniform pore distribution, a particle size between 54-68 μm, and a drug encapsulation efficiency higher than 58%, significantly improved compared to the W / O / W method. Spray drying uses a spray dryer. It is simple to operate, operates under mild conditions, and is suitable for industrial production. Summary of the Invention

[0006] The purpose of this invention is to establish a solubilizing system for improving the solubility of silymarin and to prepare silymarin-loaded polymeric microspheres, belonging to the field of pharmaceutical formulation technology. The silymarin polymeric microspheres prepared by this solubilizing system can significantly improve the solubility of silymarin.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] This invention provides a method for preparing silymarin-loaded polymeric microspheres using corn starch and nicotinamide, the method comprising the following steps:

[0009] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.5-6.8), stir and activate at 35-45℃ for 0.5-1h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 35-45℃ to constant weight to obtain pre-activated corn starch; the mass ratio of corn starch to trypsin is 1:0.2-0.3; the mass of trypsin is 0.01g / ml-0.1g / ml based on the volume of the phosphate buffer solution.

[0010] (2) The pre-activated corn starch obtained in step (1) is mixed evenly with nicotinamide and an O / W type emulsifier in deionized water to form an aqueous phase. The O / W type emulsifier is poloxamer 188, Tween 80, benzyl ether 35, tragacanth gum, and gelatin (preferably poloxamer 188).

[0011] (3) Dissolve silymarin in ethyl acetate and sonicate for 20-30 min to form an oil phase.

[0012] (4) The oil phase obtained in step (3) is slowly added dropwise to the aqueous phase obtained in step (2), and the mixture is stirred at high speed to prepare an emulsion; the rate at which the oil phase is added to the aqueous phase is 1 ml / min-2 ml / min.

[0013] (5) Place the O / W type emulsion obtained in step (4) in an ice-water bath for 2-3 hours, centrifuge, take the precipitate, freeze-dry and obtain silymarin microspheres.

[0014] Preferably, the mass ratio of the pre-activated corn starch to nicotinamide in step (2) is 1:0.1-0.5, and more preferably 1:0.25.

[0015] Preferably, the mass ratio of the pre-activated corn starch to the O / W type emulsifier in step (2) is 1:0.1-0.5, and more preferably 1:0.3.

[0016] Preferably, the volume ratio of the oil phase to the water phase in step (4) is 1:2.2-4.5, and more preferably 1:3.

[0017] Compared with existing technologies, the beneficial effects of this invention are reflected in the following: the solubilizing system for improving the solubility of silymarin provided by this invention can significantly improve the solubility of silymarin. This invention utilizes, on the one hand, the pre-activated corn starch to disrupt the surface structure of the starch; on the other hand, the pre-activated starch has a loose and porous structure with a large specific surface area compared to ordinary corn starch, which can further adsorb the poorly soluble drug silymarin. Other methods for loading silymarin polymer microspheres do not possess this advantage of loose and porous structure and large specific surface area. Attached Figure Description

[0018] Figure 1 shows the cumulative in vitro dissolution of the silymarin-loaded polymer microspheres (pre-activated starch to nicotinamide ratios of 4:1, 4:0.5, and 4:2, respectively) prepared in Examples 1-3 of the present invention, under the same conditions.

[0019] Figure 2 shows the cumulative in vitro dissolution of the silymarin-loaded polymer microspheres (preactivated starch to poloxamer 188 ratios of 1:0.3, 1:0.1, and 1:0.5, respectively) prepared in Examples 1 and 4-5 of the present invention, under the same conditions.

[0020] Figure 3 shows the cumulative in vitro dissolution of the silymarin-loaded polymer microspheres prepared in Examples 1 and 6-9 of the present invention (the O / W emulsifiers were poloxamer 188, Tween 80, benzyl ether 35, tragacanth gum, and gelatin, respectively, and the ratio of pre-activated corn starch to O / W emulsifier was 1:0.3) under the same conditions.

[0021] Figure 4 shows the cumulative in vitro dissolution rate of the silymarin-loaded polymer microspheres (oil phase to water phase ratios of 1:3, 1:2.2, 1:3.5, and 1:4.5, respectively) prepared in Example 1 and Comparative Examples 1-3 of the present invention, under the same conditions.

[0022] Figure 5 shows the cumulative in vitro dissolution of the silymarin-loaded polymer microspheres prepared in Example 1 and Comparative Example 4 of the present invention (Example 1 used pre-activated corn starch, and Comparative Example 4 used unactivated corn starch) under the same conditions. Detailed Implementation

[0023] (1) The method for determining the cumulative in vitro dissolution rate in the following examples and comparative examples is as follows:

[0024] In vitro dissolution experiments were conducted according to the method for determination of dissolution and release (paddle method) in General Chapter (0931) of Part IV of the 2020 edition of the Pharmacopoeia of the People's Republic of China. An appropriate amount of silymarin microspheres (equivalent to 100 mg of silymarin) was weighed, ground evenly, and passed through a 60-mesh sieve. 1000 ml of ultrasonically degassed distilled water was used as the dissolution medium, and the in vitro dissolution experiment was conducted at (37.0 ± 0.5) ℃ and 100 r / min. At 5 min, 10 min, 20 min, 30 min, 45 min, and 60 min, 5 mL of the dissolution solution was drawn using a syringe, and dissolution medium of the same temperature and volume was simultaneously replenished. The extracted dissolution solution was filtered using a 0.45 μm suction filter, and the peak area of ​​the filtrate at 288 nm was measured. The cumulative in vitro dissolution rate was calculated based on the linear regression equation.

[0025] Formula: Y'=Y n +(Y １ +Y ２ +Y ３ +Y ｎ -1)V １ / V ２

[0026] Y' represents the cumulative dissolution rate at the nth time; Y n V represents the actual dissolution rate measured in the nth time; １ This indicates the volume of fluid replacement, i.e., 5 ml; V ２ This indicates the total volume of the dissolution medium, i.e., 1000 ml;

[0027] Dissolution formula: Dissolution (%) =

[0028] C represents the dissolution rate of silymarin, mg / ml; V represents the volume of the dissolution medium, i.e., 1000ml; M represents the content of silymarin in the silymarin microspheres, i.e., 100mg.

[0029] (2) The high-performance liquid chromatography (HPLC) detection conditions for silymarin are as follows:

[0030] Chromatographic column: C18 reversed-phase column (150nm×4.6nm, 5μm, Phenomenex); mobile phase: methanol: 1% acetic acid aqueous solution = 5:5; flow rate: 1ml / min; detection wavelength: 288nm; column temperature: 30℃; injection volume: 10μL.

[0031] Example 1

[0032] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0033] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0034] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0035] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0036] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0037] Example 2

[0038] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0039] (2) Weigh 4g of pre-activated corn starch, 0.5g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0040] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0041] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0042] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0043] Example 3

[0044] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0045] (2) Weigh 4g of pre-activated corn starch, 2g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0046] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0047] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0048] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0049] Table 1 Formulations for Examples 1-3

[0050]

[0051] In Examples 1-3, the mass ratio of the aqueous phase to the oil phase was 3:1. Figure 1 shows the cumulative in vitro dissolution rate of the silymarin-loaded polymeric microspheres prepared in Examples 1-3 of this invention (pre-activated starch to nicotinamide ratios of 4:1, 4:0.5, and 4:2, respectively) under the same conditions. As can be seen from Figure 1, at the same dissolution time, the cumulative in vitro dissolution rate was: Example 1 > Example 2 > Example 3, indicating that Example 1 had the best solubilizing effect on silymarin, that is, when the pre-activated starch to nicotinamide ratio was 4:1, the dissolution effect of silymarin was the best.

[0052] Example 4

[0053] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0054] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 0.4g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0055] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0056] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0057] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0058] Example 5

[0059] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0060] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0061] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0062] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0063] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0064] Table 2 Formulations for Examples 1 and 4-5

[0065]

[0066] In Examples 1 and 4-5, the mass ratio of the aqueous phase to the oil phase was 3:1. Figure 2 shows the silymarin-loaded polymeric microspheres prepared in Examples 1 and 4-5 of this invention (pre-activated starch to poloxamer 188 ratio).

[0067] The cumulative in vitro dissolution rates (1:0.3, 1:0.1, and 1:0.5 respectively) under the condition that other factors are the same. Figure 2It can be seen that, under the same dissolution time, the cumulative in vitro dissolution rate is: Example 1 > Example 5 > Example 4, indicating that Example 1 has the best solubilizing effect on silymarin, i.e., the ratio of pre-activated starch to poloxamer 188 is optimal.

[0068] The dissolution effect of silymarin was best at a ratio of 1:0.3.

[0069] Example 6

[0070] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0071] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of Tween 80 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0072] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0073] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0074] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0075] Example 7

[0076] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0077] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of benzyl ether 35 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0078] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0079] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0080] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0081] Example 8

[0082] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0083] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of tragacanth gum and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0084] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0085] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0086] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0087] Example 9

[0088] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0089] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of gelatin and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0090] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0091] (4) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0092] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0093] Table 3 Formulations for Examples 1 and 6-9

[0094]

[0095] In Examples 1 and 6-9, the mass ratio of the aqueous phase to the oil phase was 3:1. Figure 3 shows the cumulative in vitro dissolution rate of the silymarin-loaded polymeric microspheres prepared in Examples 1 and 6-9 of this invention (O / W emulsifiers were poloxamer 188, Tween 80, benzyl ether 35, tragali gum, and gelatin, respectively, and the ratio of pre-activated corn starch to O / W emulsifier was 1:0.3) under the same conditions. As can be seen from Figure 3, at the same dissolution time, the cumulative in vitro dissolution rate was: Example 1 > Example 6 > Example 9 > Example 8 > Example 7, indicating that Example 1 had the best solubilizing effect on silymarin, that is, when poloxamer 188 was used as the emulsifier, the dissolution effect of silymarin was the best.

[0096] Comparative Example 1

[0097] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0098] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0099] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0100] (4) Weigh 1g of the obtained oil phase and 2.2g of the aqueous phase, slowly add the oil phase dropwise to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0101] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0102] Comparative Example 2

[0103] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0104] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0105] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0106] (4) Weigh 1g of the obtained oil phase and 3.5g of the aqueous phase, slowly add the oil phase dropwise to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0107] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0108] Comparative Example 3

[0109] (1) Disperse corn starch in a phosphate buffer solution containing trypsin (pH 6.8), stir and activate at 40°C for 1 h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 40°C to constant weight to obtain pre-activated corn starch.

[0110] (2) Weigh 4g of pre-activated corn starch, 1g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0111] (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0112] (4) Weigh 1g of the obtained oil phase and 4.5g of the aqueous phase, slowly add the oil phase dropwise to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0113] (5) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0114] Table 4 Formulations of Example 1 and Comparative Examples 1-3

[0115]

[0116] In Examples 1 and Comparative Examples 1-3, the mass ratios of the oil phase to the aqueous phase were 1:3, 1:2.2, 1:3.5, and 1:4.5, respectively. Figure 4 shows the cumulative in vitro dissolution rate of the silymarin-loaded polymer microspheres prepared in Examples 1 and Comparative Examples 1-3 of this invention (oil phase to aqueous phase ratios of 1:3, 1:2.2, 1:3.5, and 1:4.5, respectively) under the same conditions. As can be seen from Figure 4, at the same dissolution time, the cumulative in vitro dissolution rate was: Example 1 > Comparative Example 3 > Comparative Example 2 > Comparative Example 1, indicating that Example 1 had the best solubilizing effect on silymarin, that is, when the mass ratio of the oil phase to the aqueous phase was 1:3, the dissolution effect of silymarin was the best.

[0117] Comparative Example 4

[0118] (1) Weigh 4g of unactivated corn starch, 1g of nicotinamide, and 1.2g of poloxamer 188 and mix them evenly in 25ml of deionized water to form an aqueous phase;

[0119] (2) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate, sonicate for 30min to form an oil phase;

[0120] (3) Weigh 1g of the obtained oil phase and 3g of the aqueous phase, slowly add the oil phase to the aqueous phase (at a speed of about 1ml / min), and stir at high speed to prepare an emulsion;

[0121] (4) The obtained O / W type emulsion was placed in an ice-water bath for 2.5 h, centrifuged, the precipitate was collected, and lyophilized to obtain silymarin microspheres.

[0122] Table 5 Formulations of Example 1 and Comparative Example 4

[0123]

[0124] In Example 1 and Comparative Example 4, the mass ratio of oil phase to water phase was 1:3. Figure 5 shows the silymarin-loaded polymer microspheres prepared in Example 1 and Comparative Example 4 of this invention (Example 1 used pre-activated microspheres).

[0125] Comparative Example 4 uses untreated corn starch. All other factors being equal...

[0126] The cumulative in vitro dissolution rate under the same dissolution time was shown in Figure 5. As can be seen from Figure 5, the cumulative in vitro dissolution rate of Example 1 was greater than that of Comparative Example 4, indicating that Example 1 had the best solubilizing effect on silymarin, meaning that the dissolution effect of silymarin was better when using pre-activated corn starch.

[0127] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A polymeric microsphere for improving the solubility of silymarin, characterized in that... The method for preparing the microspheres includes the following steps: (1) Disperse corn starch in a phosphate buffer solution containing trypsin, stir and activate at 35-45℃ for 0.5-1h, centrifuge, wash and centrifuge repeatedly with ethanol and water, and dry in a vacuum oven at 35-45℃ to constant weight to obtain pre-activated corn starch. (2) Weigh 4g of pre-activated corn starch obtained in step (1), and mix it with 1g of nicotinamide and 1.2g of poloxamer 188 in 25ml of deionized water to form an aqueous phase; (3) Weigh 1g of silymarin and dissolve it in 25ml of ethyl acetate. Sonicate for 30min to form an oil phase. (4) Weigh 1g of the oil phase obtained in step (3) and 3g of the aqueous phase obtained in step (2), slowly add the oil phase to the aqueous phase, and stir at high speed to prepare an O / W emulsion; (5) Place the O / W type emulsion obtained in step (4) in an ice-water bath for 2.5 h, centrifuge, take the precipitate, freeze dry to obtain silymarin microspheres.

2. The polymeric microspheres for improving the solubility of silymarin as described in claim 1, characterized in that: The mass ratio of corn starch to pancreatic enzyme in step (1) is 1:0.2-0.

3.

3. The polymeric microspheres for improving the solubility of silymarin as described in claim 1, characterized in that: The mass of the pancreatic enzyme in step (1) is 0.01 g / ml to 0.1 g / ml based on the volume of the phosphate buffer solution.

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