Coating method of colon targeted delivery medicine

Abstract

The invention discloses a coating method of a colon targeted delivery drug. The method disclosed by the invention comprises the following steps: embedding a medicine coating by utilizing a mixture of starch acetate and gutta-percha; the medicine coating is obtained by coating a medicine with an inner coating material; and the inner packaging material is selected from beta-cyclodextrin, gamma-cyclodextrin, hydroxypropyl-beta-cyclodextrin, chitosan or a chitosan derivative. The release rate of the embedded medicine prepared by the method in gastric juice does not exceed 10%, and the release rate of the embedded medicine in intestinal juice exceeds 30%. Targeted delivery of the medicine in the colon is effectively achieved, toxicity of the medicine to cells is reduced, and excellent biocompatibility is shown.

Description

Technical Field

[0001] The invention belongs to the field of drug delivery systems, and in particular relates to a coating method for colon-targeted drug delivery. Background Art

[0002] In recent years, oral drug delivery systems have been widely used in the treatment of intestinal diseases (such as colitis and colon cancer) and have attracted widespread attention due to their convenience, safety and non-invasive characteristics. However, early degradation and absorption of drugs in the stomach and small intestine have become the main challenges for targeted delivery, affecting the efficacy of drugs. In order to improve the targeting and stability of drugs in the colon, many studies have been devoted to the development of different types of oral colon-targeted delivery systems, such as pH-dependent, time-dependent, pressure-dependent and microbial-dependent systems. In particular, microbial-dependent systems based on resistant starch have attracted widespread attention due to their microbial degradation mechanism in the colon. Although these systems show significant potential, some materials still have limitations, such as the brittleness of starch films and sensitivity to humidity.

[0003] The challenge for pharmaceutical technology is to provide the active substance as precisely as possible at the part of the intestine where it is needed. The formulations known from the prior art do not satisfactorily solve the problem of releasing the active substance primarily in the colon. Summary of the invention

[0004] In view of the defects or shortcomings of the prior art, the present invention provides a coating method for colon-targeted drug delivery.

[0005] To this end, the coating method for colon targeted drug delivery provided by the present invention comprises: using a mixture of acetate starch and eucommia gum to embed a drug coating; the drug coating is obtained by coating the drug with an inner packaging material; the inner packaging material is selected from β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, chitosan or a chitosan derivative.

[0006] An optional solution is that the mixture of acetate starch and eucommia gum is obtained by dissolving acetate starch and eucommia gum in an organic solvent.

[0007] An optional solution is to add a mixture of acetate starch and eucommia gum to the drug coating, and then form a film coating of the mixture of acetate starch and eucommia gum on the surface of the drug coating by a solvent evaporation method.

[0008] Optionally, the drug is tanshinone ⅡA, resveratrol, curcumin, lutein or polyphenol.

[0009] An optional solution is that the mass ratio of the total mass of eucommia gum and acetate starch to the inner packaging material is: 1:(8-11); the mass ratio of eucommia gum and acetate starch is (3-7):(93-97).

[0010] Furthermore, the embedded drug prepared by the above method is an oral preparation and has gastric tolerance. Furthermore, the release rate of the embedded drug in the gastric fluid environment does not exceed 10%, and the release rate in the intestinal fluid environment exceeds 30%.

[0011] The embedded medicine prepared by the method of the present invention is particularly suitable for treating colon-related diseases.

[0012] The coating method of the present invention aims to achieve targeted delivery and sustained release of drugs in specific intestinal sites (especially the colon) by enhancing the stability of the drugs in the gastrointestinal tract. This system can effectively avoid premature release of drugs in the stomach and small intestine, ensure that the drugs achieve efficient targeting effects in the lesion sites (colon-related diseases, such as colon cancer, etc.), improve the therapeutic effect and reduce systemic toxicity.

[0013] Compared with the traditional drug delivery system, the present invention significantly improves the concentration of the drug in the colon, thereby improving the utilization rate and efficacy of the drug, while reducing systemic toxicity. In addition, the present invention adopts a solvent evaporation method to prepare a film coating system, which has a simple process and convenient operation, avoids the destruction of the active ingredients by high temperature, and retains the biological activity of the drug. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 These are SEM images of the product prepared in Example 3; (a) is the SEM image of tanshinone ⅡA@β-cyclodextrin encapsulation; (b) is the SEM image of the product prepared in Example 3.

[0015] Figure 2 This is the particle size distribution diagram of the product prepared in Example 3.

[0016] Figure 3 The in vitro cumulative release curve and linear trend line graph of the eucommia gum / acetate starch film-coated granules prepared in Example 2-6.

[0017] Figure 4 This is a fluorescence intensity diagram of the colon of mice administered with the Eucommia gum / acetate starch film-coated granules of the present invention;

[0018] Figure 5 These are the test results of the activity of Tanshinone IIA, Eucommia gum / acetate starch / β-cyclodextrin, Tanshinone IIA@β-cyclodextrin and Eucommia gum / acetate starch / Tanshinone IIA@β-cyclodextrin particles on L929 mouse fibroblasts in the examples of the present invention; in the figure, DMEM represents: positive control; Phenol represents negative control.

[0019] Figure 6 This is a graph showing changes in fluorescence intensity representing tumor size in mice during drug administration in an embodiment of the present invention.

[0020] Figure 7 These are photos of colon tumors of mice in each treatment group when they were sacrificed on the 28th day (end point) after treatment in the examples of the present invention.

[0021] Figure 8 It is the average tumor volume of each group of mice on the 28th day in the example of the present invention.

[0022] Fig. 9 It is the average tumor mass of each group of mice on the 28th day in the example of the present invention. DETAILED DESCRIPTION

[0023] Unless otherwise specified, the scientific and technical terms used herein are understood according to the knowledge of ordinary technicians in the relevant fields.

[0024] The scheme of the present invention is applicable to drugs that need to target the intestine, such as Tanshinone ⅡA, resveratrol, curcumin, lutein or polyphenols. The following Examples 1-5 use Tanshinone ⅡA as a model drug.

[0025] The drug coating described in the present invention refers to the drug coated with an inner packaging material, wherein the inner packaging material used can enhance the water solubility of substances such as fat-soluble soluble components and block the interaction between the drug and the second coating material, enhance the solubility of the drug component in the body, improve the release efficiency of the drug, reduce biological toxicity, and improve bioavailability. It can be used as a drug carrier and as a film-coated drug core, and specifically can be selected from β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin, chitosan and its derivatives, etc. The specific coating method is selected according to the characteristics of the drug and the specific inner packaging material, or the method improved on the basis of the existing method, in order to achieve the inner packaging material coating and / or loading of the drug. The tanshinone ⅡA@β-cyclodextrin embedding material (drug coating) used in the following examples was prepared by the following method: tanshinone ⅡA was dissolved in an ethanol solution with a volume concentration of 85%, mixed and then added with a saturated β-cyclodextrin aqueous solution, and ultrasonically treated at 450W for 30min; then stirred at 40-50°C for 2.5h, then stirred in an ice bath for 8h, and allowed to stand at 4°C for more than 12h to obtain a crude tanshinone ⅡA@β-cyclodextrin embedding material; the crude tanshinone ⅡA@β-cyclodextrin embedding material was washed and dried to obtain a tanshinone ⅡA@β-cyclodextrin embedding material powder.

[0026] Among them, in the saturated β-cyclodextrin aqueous solution, the mass of β-cyclodextrin accounts for 8% of pure water; the ratio of the mass of tanshinone ⅡA powder to the volume of ethanol solution is 0.8g:10mL; the mass ratio of tanshinone ⅡA to β-cyclodextrin is 1:7; when washing the crude tanshinone ⅡA@β-cyclodextrin embedded material, 50% and 75% ethanol solutions are used for washing 3 times respectively to wash away the tanshinone ⅡA that is not embedded; the method of cool drying is adopted, and the drying is carried out for more than 12 hours.

[0027] The drug loading rate and embedding rate of the obtained tanshinone ⅡA@β-cyclodextrin embedded powder were detected by detecting the changes in the concentration of related components, and were found to be 12.3% and 98.4%, respectively.

[0028] Preparation of the acetate starch used: corn starch, acetic anhydride and pyridine were mixed and stirred at 120°C (the speed was controlled at 600-700r / min) for 2h. Then cooled to room temperature, pure water was added and stirred at room temperature for 10min. Then anhydrous ethanol was added. Finally, the precipitate was filtered and washed with pure water until it was neutral, and then dried to obtain acetate starch powder.

[0029] The ratio of the mass of corn starch to the volume of acetic anhydride and pyridine is 0.5g:10mL:0.5mL; after the reaction is completed, 5mL of pure water is added, followed by 50mL of anhydrous ethanol. During washing, the excess acid is washed away repeatedly with pure water until the pH value of the acetate starch is neutral, and then the acetate starch is dehydrated with anhydrous ethanol, and the acetate starch powder is obtained after drying in the shade. The degree of substitution is specifically: 0.4004.

[0030] The present invention is described in detail below in conjunction with specific implementations to facilitate those skilled in the art to more clearly understand the present invention. The examples cited are only used to explain the present invention and are not used to limit the scope of the present invention. In the examples of the present invention, unless otherwise specified, the raw material components such as tanshinone ⅡA and eucommia gum used are all commercially available products well known to those skilled in the art; unless otherwise specified, the technical means used are all conventional means well known to those skilled in the art.

[0031] Embodiment 1:

[0032] Dissolve 792 mg of acetate starch and 8 mg of eucommia gum in 15 mL of toluene solvent and stir to mix evenly at 75°C;

[0033] The mixed solution was added to 8 g of tanshinone ⅡA@β-cyclodextrin embedding material in small amounts and multiple times, and then the solvent evaporation method was used to form a eucommia gum / acetate starch film coating on the surface of the active ingredient@β-cyclodextrin embedding material with the mixed solution, thereby obtaining eucommia gum / acetate starch film-coated particles in which the mass ratio of eucommia gum to acetate starch of this embodiment was 1:99.

[0034] Embodiment 2:

[0035] This embodiment is different from Embodiment 1 in that the mass ratio of eucommia gum to acetate starch is 3:97.

[0036] Embodiment 3:

[0037] The difference between this embodiment and embodiment 1 is that the mass ratio of eucommia gum to acetate starch is 5:95. The electron microscope image of the product prepared in this embodiment is provided below: Figure 1 As shown, the particle sizes of tanshinone ⅡA@β-cyclodextrin particles and eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin particles prepared in Example 3 were measured at the same time. Obviously, the particle size of eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin is larger than that of tanshinone ⅡA@β-cyclodextrin, which is attributed to the eucommia gum / acetate starch film coating. Figure 2 shown.

[0038] Embodiment 4:

[0039] This embodiment is different from Embodiment 1 in that the mass ratio of eucommia gum to acetate starch is 7:93.

[0040] Embodiment 5:

[0041] This embodiment is different from Embodiment 1 in that the mass ratio of eucommia gum to acetate starch is 9:91.

[0042] Comparative Example 1:

[0043] This comparative example is different from Example 1 in that no acetate starch is added, that is, 800 mg of eucommia gum is mixed with 30 mL of toluene solvent, stirred and melted at 75°C, and the solution is added in small amounts and multiple times to 8 g of tanshinone ⅡA@β-cyclodextrin embedding material to prepare eucommia gum film-coated particles.

[0044] Comparative Example 2:

[0045] This comparative example is different from Example 1 in that no eucommia gum is added, that is, 800 mg of acetate starch is dissolved in 30 mL of toluene solvent at 40-60°C for 20-40 min, and the solution is added in small amounts and multiple times to 8 g of tanshinone ⅡA@β-cyclodextrin embedding material to prepare acetate starch film-coated particles.

[0046] The products prepared in the above examples and comparative examples were subjected to in vitro simulated release:

[0047] Test method: 2g of each coated granule was placed in a 100mL centrifuge tube (3 samples in parallel); 60mL of artificial simulated gastric juice with a pH of 1.2 (the mass ratio of sodium chloride and pepsin was 1g:1.6g, and the pH was adjusted to 1.2 with 6M hydrochloric acid solution) was first added, and the tube was placed in a constant temperature oscillator at 37±0.5℃ and 100rpm. 2mL of release solution was taken out every half an hour, and an equal amount of fresh medium (artificial simulated gastric juice with a pH of 1.2) was added, and the release test was continued after the medium solution was placed in a constant temperature oscillator; after 2h of release, the medium solution was removed by centrifugation, and 60mL of artificial simulated intestinal juice with a pH of 6.8 (the mass ratio of potassium dihydrogen phosphate and pancreatic enzyme was 3.4g:5g, and the pH was adjusted to 6.8 with 0.1M sodium hydroxide solution) was added. 2mL of release solution was taken out at the preset time point (sampling was performed once every hour), and an equal amount of fresh medium (pH 6.8 artificial simulated intestinal fluid) and then placed in a constant temperature oscillator to continue the release test for 6 hours; the liquid was taken out and the drug release amount was detected by ultraviolet spectrophotometer, and then the cumulative release curve was prepared, and the cumulative release rate after treatment with different artificial simulated fluids was calculated. The results are shown in Figure 3 And as shown in Table 1.

[0048] Table 1 In vitro release rate of film-coated granules

[0049]

[0050] From the comparison of the data in the above table, it can be seen that the eucommia gum / acetate starch film-coated particles obtained, as the mass ratio of eucommia gum in the entire film increases, the cumulative release rate of the particles in the entire simulated release system decreases significantly. Considering the function of the film coating, a reasonable formula can ensure the minimum cumulative release rate in gastric juice while its eucommia gum will not hinder the release of the active ingredient tanshinone ⅡA in the intestine.

[0051] Embodiment 6:

[0052] This example is a drug (fluorescence) distribution test in mice. The fluorescent dye indocyanine green is used as a model drug to prepare the core particle indocyanine green @ β-cyclodextrin embedding material: 10 mg indocyanine green is mixed with 5 mL methanol solution, and after 450W ultrasound for 5-10 minutes, a saturated β-cyclodextrin aqueous solution is added, and 450W ultrasound is continued for 30 minutes. Then, the reaction is stirred at 40-50°C for 2-3 hours. After the reaction is completed, the mixture is stirred in an ice bath for 8 hours, and the mixture is allowed to stand for more than 12 hours at 4°C to obtain a crude indocyanine green @ β-cyclodextrin embedding material; the crude indocyanine green @ β-cyclodextrin embedding material is washed and dried to obtain an indocyanine green @ β-cyclodextrin embedding material powder.

[0053] The method of Example 1 was used to prepare eucommia gum / acetate starch film-coated granules having a mass ratio of eucommia gum to acetate starch of 5:95.

[0054] Drug (fluorescence) distribution test in mice Test method: The mice were fasted for 18 h before the experiment; after oral administration of indocyanine green @ β-cyclodextrin particles and eucommia gum / acetate starch / indocyanine green @ β-cyclodextrin particles prepared in Example 6 (dosage: 80 mg indocyanine green / kg body weight), the mice were euthanized at predetermined time points (0.5, 1, 2, 4, 6, 12 and 24 h) and the intestinal tissue was dissected to analyze the biodistribution of the fluorescent dye in indocyanine green in the gastrointestinal tract by scanning and analyzing the small animal in vivo imaging system, and then the fluorescence intensity diagram of the mouse colon was drawn. The results are shown in Figure 2. Figure 4 express.

[0055] according to Figure 4 It can be found that the fluorescence intensity of indocyanine green released by eucommia gum / acetate starch film-coated particles in the colon is higher than that of indocyanine green@β-cyclodextrin encapsulated particles without film coating, which indicates that eucommia gum / acetate starch film-coated particles can effectively deliver bioactive ingredients to the colon and increase the effective concentration of drugs in the colon.

[0056] In vitro cytotoxicity assay:

[0057] Test method: The in vitro cytotoxicity of tanshinone ⅡA, eucommia gum / acetate starch / β-cyclodextrin (i.e., tanshinone ⅡA was not added on the basis of Example 3), tanshinone ⅡA@β-cyclodextrin, and eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin particles prepared in Example 3 on L929 mouse fibroblasts was evaluated by MTT method. Cells cultured in DMEM cell culture medium were used as positive control, and cells cultured in 0.64% phenol DMEM culture medium were used as negative control. Then, the cell survival rate was calculated and a cell survival rate bar graph was drawn.

[0058] The results are as follows Figure 5 As shown in the figure, it can be seen that the solubility of the bioactive ingredient Tanshinone ⅡA is low, resulting in high local concentration and high cytotoxicity; while other materials all show good cell compatibility. This shows that Eucommia gum / acetate starch / Tanshinone ⅡA@β-cyclodextrin film-coated particles are oral sustained-release particles with biosafety and are harmless to humans.

[0059] Tumor treatment effect:

[0060] Test method: mice with orthotopic colon cancer tumors expressing luciferase were divided into three groups, with five mice in each group; physiological saline, tanshinone ⅡA@β-cyclodextrin and eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin particles prepared in Example 3 were administered respectively; mice were orally administered once every two days (each administration dosage was: 80 mg tanshinone ⅡA / kg body weight), and the tumor size was measured every 14 days using a small animal in vivo imaging system, and fluorescent images were drawn. The results are shown in Figure 2. Figure 6 After 28 days of treatment, the mice were euthanized by cervical dislocation. The tumor and digestive system tissues of each group of mice were collected and photographed (eg Figure 7 ), using tumor volume (eg Figure 8 ) and weight (such as Fig. 9 ).

[0061] from Figure 6 It can be found that as the time extends from 0 days to 28 days, the fluorescence intensity of the saline group continues to rise, while the tanshinone ⅡA@β-cyclodextrin group shows a trend of first rising and then remaining stable. Surprisingly, the fluorescence intensity of the eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin group shows a continuous downward trend. These results confirm that eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin has the best in vivo anticancer effect. This is also confirmed by the tumor weight and volume after 28 days, as shown in Figure 2. Figure 7 As shown. Figure 8 and Fig. 9 It can be found that the eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin group had the smallest tumor. These findings strongly prove that eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin particles can slow down or even shrink the growth of HCT116 tumors in the colon. More importantly, it is proved that eucommia gum / acetate starch / tanshinone ⅡA@β-cyclodextrin particles can well and specifically deliver the bioactive substance tanshinone ⅡA to in situ colon tumors, thereby more effectively treating tumors.

Claims

1. A method for encapsulating a colon-targeted drug delivery, characterized in that: The method comprises: using a mixture of acetate starch and eucommia gum to embed a drug coating; the drug coating is obtained by coating the drug with an inner packaging material; the inner packaging material is selected from beta-cyclodextrin, gamma-cyclodextrin, hydroxypropyl-beta-cyclodextrin, chitosan or a chitosan derivative.

2. The method for encapsulating a colon-targeted drug delivery according to claim 1, characterized in that: The mixture of acetate starch and eucommia gum is obtained by dissolving acetate starch and eucommia gum in an organic solvent.

3. The method for encapsulating a colon-targeted drug delivery according to claim 2, characterized in that: The mixture of acetate starch and eucommia gum is added into the drug coating, and then a film coating of the mixture of acetate starch and eucommia gum is formed on the surface of the drug coating by a solvent evaporation method.

4. The method for coating a colon-targeted drug delivery according to claim 1, characterized in that: The drug is tanshinone ⅡA, resveratrol, curcumin, lutein or polyphenol.

5. The method for coating a colon-targeted drug delivery according to claim 1, characterized in that: The mass ratio of the total mass of eucommia gum and acetate starch to the inner packaging material is: 1: (8-11); the mass ratio of eucommia gum and acetate starch is (3-7): (93-97).

6. The embedded drug prepared by the method of claim 1, characterized in that: The embedded drug is an oral preparation and has gastric tolerance.

7. The embedded drug according to claim 6, characterized in that: The release rate of the embedded drug in the gastric fluid environment is no more than 10%, and the release rate in the intestinal fluid environment is more than 30%.

8. Use of the embedded drug prepared by the method of claim 1 for preparing drugs for treating colon-related diseases.

Images