Starch gel as well as preparation method and application thereof

Abstract

The invention relates to starch gel as well as a preparation method and application thereof. The preparation method comprises the following steps: dispersing starch serving as a raw material in a DMSO / water mixed solution, and performing ultrasonic treatment to obtain the starch gel. The preparation method of the starch gel provided by the invention is efficient, the viscosity range of the starch gel is wide, the starch gel can effectively adapt to different application occasions, compared with starch gel prepared by a common aging retrogradation method and an enzyme method, the starch gel has higher preparation efficiency, and the starch gel has good transdermal performance and antibacterial activity and can be used for preparing the antibacterial starch gel. The composition can be effectively used for adjuvant therapy of diseases such as psoriasis.

Description

Technical Field

[0001] The present invention relates to the medical field, and in particular to a starch gel and a preparation method and application thereof. Background Art

[0002] At present, the preparation methods of starch gel mainly include gelatinization and retrogradation, extrusion and chemical crosslinking. The gelatinization and retrogradation method refers to gelatinizing starch in a boiling water bath for more than 30 minutes to disperse it into starch paste, and then regenerating it at low temperature for 24 hours to prepare starch gel. Adding ethanol to the gelatinized starch paste can shorten the retrogradation time to 4 hours. The extrusion method is to mix a part of the pre-gelatinized starch with the ungelatinized starch, extrude it through a rotary extruder, treat it at high temperature, and cool it to obtain starch gel. The chemical method uses crosslinking agents such as citric acid and acrylamide to connect two or more starch chains on the starch main chain to prepare composite starch gel. The preparation of starch gel by chemical crosslinking will add a variety of chemical reagents, and the correlation and safety between the multiple reagents need to be considered. However, due to the limitations of the natural starch granule structure and molecular structure, the physical method has a cumbersome preparation process, and there are problems such as long time consumption and acid / alkali degradation; at the same time, the starch gel prepared by the physical method also needs to be regulated by pre-gelatinization, wet heat treatment, and addition of colloids. The gel properties fail to fully meet the application requirements.

[0003] Currently, the most common continuous phase of starch gel is water. Some drugs have limited solubility in water, which limits the further application of starch gel in drug carriers.

[0004] DMSO is an oily liquid with a large dipole moment and a high dielectric constant. It is green and safe, has good skin penetration and drug dissolving ability, can effectively improve the absorption of transdermal drugs, and is also widely used as a gel continuous phase. Based on these characteristics, DMSO is widely used in topical preparations or skin care products, such as diclofenac sodium topical solution, compound heparin sodium-DMSO gel, etc. American Livebetter and other companies have also launched an aloe vera gel containing 70% DMSO. With the help of DMSO's penetration-promoting properties, this aloe vera gel has better moisturizing and anti-inflammatory effects.

[0005] DMSO is also an important solvent in the starch modification process. In the previous study, the applicant used DMSO to develop a new method for preparing nano starch, namely the ultrasound-assisted DMSO reverse precipitation method, which can effectively reduce the particle size of ordinary starch, and then prepare nano starch with controllable morphology. Furthermore, in the process of preparing nano starch by ultrasound-assisted DMSO reverse precipitation, the applicant found that when the Trichosanthes starch was placed in a DMSO solution under ultrasonic conditions, it could be quickly converted into starch gel. The applicant then used this method to treat a variety of starches (including type A potato starch, type B corn starch, type C Trichosanthes starch), and found that all starches could be quickly gelled within 30 minutes, but due to differences in the basic properties of starch (such as linearity, etc.), the viscosity range of the prepared starch gel was different. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for preparing a starch gel that is applicable to various crystalline starches, has short time consumption, high efficiency, controllable product morphology, recyclable solvents, and has good skin permeability and antibacterial functions. Starch is used as a raw material, dispersed in a mixed solution of DMSO / water, and subjected to ultrasonic treatment to prepare a starch gel, which can effectively prevent the growth of bacteria such as Escherichia coli and Staphylococcus aureus. Adding drugs to the gel can promote the skin absorption of the drugs and improve the bioavailability of the drugs.

[0007] The technical scheme of the present invention is as follows:

[0008] A method for preparing starch gel comprises the following steps:

[0009] a. Prepare a mixed solution of pure water and DMSO;

[0010] b. Add starch and disperse evenly;

[0011] c. Ultrasonication to obtain starch-DMSO gel.

[0012] Preferably, the drug can be added to the mixed solution of pure water and DMSO in step a, and then dispersed until completely dissolved; the drug can also be added after the starch gel is formed in step c, but adding the drug to the mixed solution of pure water and DMSO first can make the drug system more uniform;

[0013] Preferably, the drug can be adapalene, methotrexate, cyclosporine, tacrolimus, acitretin, leflunomide, azathioprine, prednisone, methylprednisone, betamethasone, Diprosone, prednisolone, dexamethasone and other small molecule drugs; the drug addition amount is 0-15g / L;

[0014] Preferably, in step a, the volume concentration of DMSO in the mixed solution is 70-90%;

[0015] Preferably, the starch in step b is selected from one or more of A-type crystalline corn starch (Corn Starch), B-type crystalline potato starch (Potato Starch), and C-type crystalline trichosanthes starch (TKP Starch); the starch input amount is 60-100 g / L;

[0016] Preferably, in step c, the ultrasonic conditions are: 200-500W ultrasonic for 5 to 15 minutes; wherein, an ultrasonic power less than 200W will make it difficult to form a gel, and exceeding 500W will affect the system temperature and the loading of drugs; preferably 400W ultrasonic for 10 minutes;

[0017] The present invention can obtain starch gels of various different viscosities by controlling different feed ratios and ratios of DMSO to water.

[0018] The gel obtained by the above preparation method is used for transdermal administration.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The starch gel preparation method provided by the present invention has a higher preparation efficiency than starch gel prepared by the common aging and regeneration methods and enzymatic methods, and can effectively improve the production efficiency of different starch gels.

[0021] (2) The starch gel provided by the present invention has a wide viscosity range and can be effectively adapted to different application scenarios.

[0022] (3) The starch gel provided by the present invention has good skin transdermal performance and antibacterial activity, and can be effectively used as an adjuvant treatment for diseases such as psoriasis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Scanning electron micrographs of starch gels prepared under different conditions after drying (Corn, Potato, and TKP are original starches, and the rest are modified starches after gelatinization);

[0024] Figure 2 XRD patterns of starch gels prepared under different conditions after drying (where Corn, Potato, and TKP are original starches, and the rest are modified starches after gelatinization, I is the XRD characterization of TKP starch and its gelatinization, II is the XRD characterization of potato starch and its gelatinization, and III is the XRD characterization of corn starch and its gelatinization);

[0025] Figure 3 Composite modulus diagram of starch gel prepared under different conditions (storage modulus G' and loss modulus G");

[0026] Figure 4The fluidity diagrams of starch gels with different viscosity values ​​are A1, B1, and B2;

[0027] Figure 5 The methotrexate loading capacity of Trichosanthes koji starch gel B2 (TKGH);

[0028] Figure 6 The loading capacity of Trichosanthes kirilowii starch gel B2 (TKGH) on adapalene;

[0029] Figure 7 Methotrexate release profiles of Trichosanthes starch gels B1 (TKGM) and B2 (TKGH);

[0030] Figure 8 The inhibitory ability of Trichosanthes starch gel B2 (TKGH) on bacterial flora. A, B, and C are Escherichia coli, D, E, and F are Staphylococcus aureus. A and D are Trichosanthes starch gels, B and E are blank controls, and C and F are starch gels prepared by aging and retrogradation method.

[0031] Fig. 9 Toxicity experiments of starch gels prepared under different conditions (TKGM B1, TKGH B2, CGM F2, CGH E4, PGMZ3, PGH Z2);

[0032] Fig.10 Figure 3. Treatment experiment of Trichosanthes kirilowii starch gel B1 (TKGM) and B2 (TKGH) on psoriasis mice. DETAILED DESCRIPTION

[0033] Embodiment 1:

[0034] Gel preparation experiment:

[0035] The preparation method of starch gel is as follows: take starch (addition amount is 60, 80, 100 g / L), add 25 ml of DMSO / water solution (wherein the DMSO concentration is 90%, 85%, 80%, 75%), stir and mix, and then ultrasonicate at a power of 400 W for 10 minutes to obtain starch gel.

[0036] At 25°C and standard atmospheric pressure, the viscosity of the starch gel of each experimental group was measured and recorded using a viscometer. The specific preparation conditions are shown in Table 1. Figure 1 , XRD Figure 2 , the composite modulus is Figure 3 , the relationship between viscosity and fluidity can be seen in Figure 4 .

[0037] The results show that after ultrasound-assisted DMSO solvent treatment, starch will be transformed into starch gel with different viscosity ranges; SEM results show that the morphology of starch changes from granular to porous lamellar; XRD results show that starch will change from the original A, B, and C type starch to amorphous V-type starch, and the composite modulus results show that starch gel has good gel properties in the temperature range of -20℃-40℃; and as the viscosity continues to increase, the starch gel shows the characteristics of a gel.

[0038] Table 1 Preparation conditions of different starch gel samples

[0039]

[0040]

[0041] The “-” indicates that no gel could be obtained.

[0042] Example 2

[0043] Methotrexate loading experiment:

[0044] The B2 (high-viscosity Trichosanthes fruit pulp starch gel) formulation of Example 1 was used to investigate the use of high-viscosity Trichosanthes fruit pulp starch gel as a carrier to test its loading capacity for the soluble small molecule drug methotrexate.

[0045] The difference from the experiment of group B2 of Example 1 is that methotrexate was first added to the DMSO / water solution, and then the starch from the fruit pulp of Trichosanthes kirilowii was added, and ultrasonic treatment was performed.

[0046] The specific operation is as follows: take 0.5g of methotrexate, add 25mL of DMSO / water mixed solution containing 85% DMSO, disperse until completely dissolved, then add 2.0g (i.e. 80g / L) of Trichosanthes fruit pulp starch, stir and mix, and ultrasonicate (400W ultrasonicate for 10min) to obtain the drug-loaded starch gel TKGH-MTX. Compared with water, TKGH-MTX can effectively carry methotrexate. The results are as follows Figure 5 .

[0047] Example 3

[0048] Adapalene loading experiment:

[0049] The B2 (high-viscosity Trichosanthes fruit pulp starch gel) formulation of Example 1 was used to investigate the use of high-viscosity Trichosanthes fruit pulp starch gel as a carrier to test its loading capacity for the poorly tolerant small molecule drug adapalene.

[0050] The difference from the experiment of group B2 of Example 1 is that adapalene is first added to the DMSO / water solution, and then the starch from the fruit pulp of Trichosanthes kirilowii is added, and ultrasound is performed.

[0051] The specific operation is as follows: take 0.5g of adapalene, add 25mL of DMSO / water mixed solution containing 85% DMSO, disperse until completely dissolved, then add 2.0g (i.e. 80g / L) of Trichosanthes fruit pulp starch, stir and mix, and ultrasonicate at 400W for 10min to obtain drug-loaded starch gel. Compared with water, TKGH-adapalene can effectively carry adapalene. The results are as follows Figure 6 .

[0052] Example 4

[0053] Methotrexate transdermal test:

[0054] The formulations of group B1 (low-viscosity Trichosanthes fruit pulp starch gel) and B2 (high-viscosity Trichosanthes fruit pulp starch gel) of Example 1 were used, and low- and high-viscosity Trichosanthes fruit pulp starch gels were used as carriers to investigate their transdermal release of methotrexate on pig skin.

[0055] The difference from the experiments of groups B1 and B2 of Example 1 is that methotrexate was first added to the DMSO / water solution, and then the starch from the fruit pulp of Trichosanthes kirilowii was added, and ultrasonic treatment was performed.

[0056] Specifically: take two portions of methotrexate, 1.5 g each, add 25 mL of DMSO / water mixed solution containing 85% and 90% DMSO respectively, disperse until completely dissolved, then add 2.0 g (i.e. 80 g / L) of Trichosanthes fruit pulp starch, stir and mix well, and ultrasonicate at 400W for 10 min to obtain methotrexate-high and low viscosity Trichosanthes fruit pulp starch gels, i.e. TKGH-MTX and TKGM-MTX.

[0057] Compared with the blank DMSO matrix or water matrix, the permeability of the starch gel of Trichosanthes fruit pulp to methotrexate was better; compared with the DMSO matrix and water matrix, the cumulative permeation of the low-viscosity starch gel (TKGM-MTX) was 1.09 and 1.88 times at 24 hours, respectively; the cumulative permeation of the high-viscosity starch gel (TKGH-MTX) was 1.33 and 2.31 times at 24 hours, respectively. Figure 7 .

[0058] Example 5

[0059] Gel antibacterial test:

[0060] E. coli and S. aureus were cultured overnight in an incubator (12 h, 37 °C, 5% CO2), and the final concentration of each strain was adjusted to 3 × 10 4CFU / mL. 100 μl of bacterial culture was inoculated in 10 ml of agar slurry (0.85% NaCl, 0.3% agar), and then B2 (high-viscosity Trichosanthes fruit pulp starch gel) of Example 1 was applied on top of the agar layer and further contacted with the bacteria for 24 hours. Blank culture medium and starch hydrogel prepared by aging and regeneration method were used as controls.

[0061] The antibacterial results showed that compared with the starch hydrogel prepared by the aging and regeneration method, the starch gel could effectively inhibit the growth of bacterial flora. At 24 hours, the growth of Escherichia coli and Staphylococcus aureus was completely inhibited, and no bacterial flora was found. Figure 8 A, B, and C are Escherichia coli, D, E, and F are Staphylococcus aureus, A and D are added with high-viscosity Trichosanthes fruit pulp starch gel B2, B and E are blank controls, and C and F are added with starch gel prepared by the existing aging and regeneration method.

[0062] Example 6

[0063] Gel mouse toxicity test:

[0064] The high-viscosity potato starch gel (F2), low-viscosity potato starch gel (E4), high-viscosity corn starch gel (Z2), low-viscosity corn starch gel (Z3), low-viscosity Trichosanthes fruit pulp starch gel (B1), and high-viscosity Trichosanthes fruit pulp starch gel (B2) of Example 1 were used as carriers to test the irritation effect of starch gel on the skin.

[0065] Thirty-five C57BL / 6J mice were divided into seven groups. The back hair was removed with depilatory cream. The blank group was smeared with 30 ml of normal saline daily, and the experimental group was smeared with high-viscosity potato starch gel (F2 PGH), low-viscosity potato starch gel (E4PGM), high-viscosity corn starch gel (Z2 CGH), low-viscosity corn starch gel (Z3 CGM), high-viscosity Trichosanthes fruit pulp starch gel (B2 TKGH), and low-viscosity Trichosanthes fruit pulp starch gel (B1 TKGM) daily for 15 days. After the experiment, all mice were fasted for 4 hours, anesthetized with isoflurane, blood was collected from the eye sockets, and the supernatant was centrifuged after standing. The indicators were measured, and the skin, heart, liver, spleen, lung, and kidney were collected to identify the changes in related tissues.

[0066] The results showed that after the mice were smeared with gel, no obvious changes were found in their tissues, and the liver biochemical indicators were normal, with no significant difference from the normal group, indicating that the starch gel of vegetation had no acute toxicity. Fig. 9 .

[0067] Example 7

[0068] Psoriasis adjuvant treatment experiment:

[0069] The low-viscosity trichosanthes fruit pulp starch gel (TKGM-MTX) and high-viscosity trichosanthes fruit pulp starch gel (TKGH-MTX) of methotrexate prepared in Example 4 were used to test the adjuvant therapeutic ability of starch gel loaded with methotrexate for psoriasis.

[0070] 42 Balb / c mice were divided into 7 groups. After removing the hair on the back with depilatory cream, all mice except the normal group were treated with imiquimod cream 62.5 mg / d for 5 consecutive days. Then the experimental group was treated with the prepared low-viscosity starch gel of methotrexate from the pulp of Trichosanthes fruit (TKGM-MTX), the starch gel prepared with high-viscosity starch gel of methotrexate from the pulp of Trichosanthes fruit (TKGH-MTX) and the commercially available calcipotriol cream (Cal). The blank control group was treated with an equal amount of normal saline, and the positive control group was treated with calcipotriol cream for 5 days. After the experiment, all mice were fasted for 4 hours, anesthetized with isoflurane, blood was collected from the orbits, and the supernatant was centrifuged after standing to measure the indicators, and the spleen and skin were collected to identify the changes in related tissues.

[0071] The results showed that after the mice were treated with gel for 4 days (from the 6th day to the 9th day), the PASI score was significantly reduced compared with the IMQ model group, and the erythema and scales were significantly alleviated. The therapeutic effects of the two groups were comparable. The starch gel without drug loading also had a certain therapeutic effect.

[0072] To further compare the effects of medicated starch gel and calcipotriol in the IMQ-induced psoriasis-like mouse model, H&E staining was performed on the dorsal skin samples of each group of mice. Histopathological analysis showed that compared with the IMQ model group, the epidermal thickness of the medicated starch gel and calcipotriol groups was significantly decreased, the inflammatory cell infiltration in the dermis was reduced, and hyperkeratosis and parakeratosis were significantly improved. The expression levels of TNF-α, IL-1β and IL-17 / 23 in psoriasis skin tissues were detected by ELISA kits.

[0073] The results showed that in the starch gel and calcipotriol groups, the expression levels of TNF-α, IL-1β and IL-17 / 23 were restored to near normal levels. The spleen length and spleen weight index were also significantly reduced in the starch gel and calcipotriol treatment groups. Fig.10 .

[0074] The experimental results show that starch gels exhibit high efficiency and stability in loading multiple therapeutic agents and have sustained transdermal release properties. Notably, animal studies have shown that starch gels exhibit intrinsic therapeutic effects even in the absence of loaded drugs, especially in regulating psoriasis. Starch gels can be a promising formulation for transdermal treatment of psoriasis.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing starch gel, characterized in that: The following steps are involved: a. Prepare a mixed solution of pure water and DMSO; b. Add starch and disperse evenly; c. Ultrasonication to obtain starch-DMSO gel.

2. The preparation method according to claim 1, characterized in that: The drug is added to the mixed solution of pure water and DMSO in step a, and then dispersed until completely dissolved; or the drug is added after the starch-DMSO gel is formed in step c.

3. The preparation method according to claim 2, characterized in that: The drug is any one or more of adapalene, methotrexate, cyclosporine, tacrolimus, acitretin, leflunomide, azathioprine, prednisone, methylprednisone, betamethasone, Diprosone, prednisolone, and dexamethasone; the drug addition amount is 0-15 g / L.

4. The preparation method according to claim 1, characterized in that: In step a, the volume concentration of DMSO in the mixed solution is 70-90%.

5. The preparation method according to claim 1, characterized in that: The starch in step b is selected from any one or more of A-type crystalline structure corn starch, B-type crystalline structure potato starch, and C-type crystalline structure Trichosanthes starch.

6. The preparation method according to claim 5, characterized in that: The starch input amount is 60-100g / L.

7. The preparation method according to claim 1, characterized in that: In step c, the ultrasonic condition is 200-500W for 5-15min.

8. The preparation method according to claim 7, characterized in that: In step c, the ultrasonic condition is 400W ultrasound for 10 min.

9. The starch gel prepared by the preparation method according to any one of claims 1 to 8.

10. The use of the starch gel according to claim 9, characterized in that It is used for transdermal administration.

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