Preparation method of external gel containing allantoin liposome

Abstract

The invention relates to a preparation method of external gel containing allantoin lipidosome and application of the external gel to drugs or cosmetics, and belongs to the technical field of nano-carriers. The method comprises the following steps: dissolving allantoin in an ethanol water solution, and fully stirring and dissolving to obtain an allantoin ethanol water solution; then adding glycolipid into the allantoin ethanol water solution, fully and uniformly stirring, and maintaining for 30 minutes; transferring into concentration equipment, concentrating at 60 DEG C under reduced pressure to be thick, adding glycyrrhizic acid ethanol water solution, continuously concentrating and drying to obtain solid, and crushing to obtain solid powder; and finally, dissolving the solid powder obtained in the step 3 into water to obtain gel. The prepared gel is applied to promotion of wound healing and moisturizing for external use.

Description

Technical Field

[0001] The invention relates to the technical field of nano-carriers, in particular to a method for preparing an external gel containing allantoin liposomes and application of the gel in medicines or cosmetics. Background Art

[0002] Allantoin, also known as N-(2,5-dioxo-4-imidazolinyl)urea, has a molecular formula of C4H6N4O3. It is a hydantoin derivative that exists in nature, in allantoic fluid, fetal urine, and in some plants such as tobacco seeds, beets, and malt. It is the oxidized product of uric acid, ureidohydantoin. Allantoin was first extracted from the underground stems of Boraginaceae plants. It has physiological functions such as promoting cell growth, accelerating wound healing, and softening keratin. It is a good healing agent and anti-ulcer agent for skin trauma. It can be used to relieve and treat xerosis, scaly skin diseases, skin ulcers, gastrointestinal ulcers and inflammation. It has good therapeutic effects on osteomyelitis, diabetes, cirrhosis, and acne. It is mainly used in the fields of cosmetics and medicine. Adding it to cosmetics can maintain skin moisture and delay skin aging. Adding allantoin to medicines can promote cell generation and accelerate wound healing. It is helpful in relieving skin discomfort, treating chronic surgical ulcers, gastric ulcers in experimental animals, and gastric and duodenal ulcers.

[0003]

[0004] In addition, since allantoin is an amphoteric compound, it can combine with multiple substances to form complex salts, has the functions of light protection, sterilization, analgesia, and anti-oxidation, can keep the skin hydrated, moisturized and soft, and is a special additive for beauty and hairdressing cosmetics, and is widely used as an additive for freckle cream, acne solution, shampoo, soap, toothpaste, shaving lotion, hair conditioner, astringent, antiperspirant and deodorant lotion, etc. Cosmetics with allantoin have the functions of protecting tissues, being hydrophilic, absorbing water and preventing water from radiating; hair milk, hair cream and shampoo with allantoin have the functions of protecting hair, preventing hair from splitting and growing continuously; lipstick and face cream with allantoin can make skin and lips soft and elastic, and have a beautiful luster.

[0005] However, in actual application, it can be found that although allantoin is soluble in hot water, hot ethanol and dilute sodium hydroxide solution, it is only slightly soluble in water and ethanol, and almost insoluble in butyl ether and chloroform. At room temperature and pressure, its solubility in water is only 0.6g. At the same time, it is also an amphoteric compound with limited transdermal ability. In the application process, especially in the field of daily chemicals, it often relies on a large amount of emulsifiers, oils, etc. to further shape it, which is not conducive to the healing application on skin wounds. It has no obvious anti-inflammatory effect on symptoms such as wound inflammation that are prone to occur during the healing process, and often requires combined medication. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing an external gel containing allantoin liposomes, so as to obtain an external gel dressing which has high biocompatibility, stability, good transdermal effect, and anti-inflammatory and antibacterial effects.

[0007] In order to solve the above problems, the technical solution of the present invention is: a method for preparing an external gel containing allantoin liposomes, mainly comprising the following steps:

[0008] Step 1: dissolving allantoin in an ethanol aqueous solution, and fully stirring to dissolve to obtain an allantoin ethanol aqueous solution;

[0009] Step 2, adding glycolipid to the allantoin ethanol aqueous solution, stirring well and maintaining for 30 minutes;

[0010] Step 3, concentrating under reduced pressure at 60°C until it becomes viscous, adding glycyrrhizic acid ethanol aqueous solution, continuing to concentrate and dry until solid, and crushing to obtain solid powder;

[0011] Step 4: dissolving the solid powder obtained in step 3 in water to obtain a gel.

[0012] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that: in the allantoin ethanol aqueous solution of step 1, the concentration of allantoin is 1 to 6 mg / mL, and the volume concentration of ethanol in the ethanol aqueous solution used is 20 to 90%;

[0013] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that the final concentration of the glycolipid added in step 2 is 10 to 120 mg / mL.

[0014] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that the concentration of the glycyrrhizic acid ethanol aqueous solution added in step three is 20 to 240 mg / mL.

[0015] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that the volume concentration of ethanol in the ethanol aqueous solution used in step three is 20-90%.

[0016] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that the weight ratio of the solid powder to water in step 4 is 1:0.5 to 1:2.

[0017] Furthermore, the method for preparing the external gel containing allantoin liposomes is characterized in that the prepared gel is used externally to promote wound healing and moisturize.

[0018] The present invention has the following advantages over the prior art:

[0019] Allantoin is an amphoteric compound that can combine with multiple substances to form a complex salt. It has the effects of light protection, sterilization, analgesia, and antioxidant. It has good moisturizing, skin healing promotion, and anti-aging effects. The present invention first uses glycolipids to encapsulate allantoin, and further uses glycyrrhizic acid to secondary encapsulate the encapsulated material, and redissolves the secondary encapsulated powder to form a supramolecular gel. The use of glycolipids to encapsulate allantoin can increase the skin permeability of allantoin, solve its shortcoming of poor permeability, and further target the inflammatory condition that is prone to occur during the skin healing process. The gel formed by glycyrrhizic acid can effectively inhibit the inflammatory state and further promote skin healing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Comparison of wound healing effects in mice

[0021] Figure 2 Comparison of changes in transepidermal water loss rate in mice DETAILED DESCRIPTION

[0022] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0023] Example 1

[0024] Weigh 100 mg of allantoin and dissolve it in 100 mL of 90% ethanol-water to obtain a 1 mg / mL allantoin solution. Add 1 g of glycolipid powder under stirring and stir for 30 minutes. Concentrate the allantoin-glycolipid solution under reduced pressure at 60°C until it becomes viscous. Add 100 mL of 90% ethanol-water solution containing 20 mg / mL glycyrrhizic acid and continue to concentrate to a solid. Grind to obtain a solid powder. Take 1 g of the solid powder, add 0.5 mL of deionized water, and stir thoroughly to obtain a gel.

[0025] Example 2

[0026] Weigh 600 mg of allantoin and dissolve it in 100 mL of 20% ethanol-water to obtain a 6 mg / mL allantoin solution. Add 12 g of glycolipid powder under stirring and stir thoroughly for 30 minutes. Concentrate the allantoin-glycolipid solution under reduced pressure at 60°C until it becomes viscous. Add 100 mL of 80% ethanol-water solution containing 240 mg / mL glycyrrhizic acid and continue to concentrate to a solid. Grind to obtain a solid powder. Take 1 g of the solid powder, add 2 mL of deionized water, and stir thoroughly to obtain a gel.

[0027] Example 3

[0028] Weigh 300 mg of allantoin and dissolve it in 100 mL of 50% ethanol-water to obtain a 3 mg / mL allantoin solution. Add 8 g of glycolipid powder under stirring and stir well for 30 minutes. Concentrate the allantoin-glycolipid solution under reduced pressure at 60°C until it becomes viscous. Add 100 mL of 20% ethanol-water solution containing 140 mg / mL glycyrrhizic acid and continue to concentrate to a solid. Grind to obtain a solid powder. Take 1 g of the solid powder, add 1 mL of deionized water, and stir well to obtain a gel.

[0029] Example 4

[0030] Weigh 200 mg of allantoin and dissolve it in 100 mL of 50% ethanol-water to obtain a 2 mg / mL allantoin solution. Add 6 g of glycolipid powder under stirring and stir well for 30 minutes. Concentrate the allantoin-glycolipid solution under reduced pressure at 60°C until it becomes viscous. Add 100 mL of 20% ethanol-water solution containing 100 mg / mL glycyrrhizic acid and continue to concentrate to a solid. Grind to obtain a solid powder. Take 1 g of the solid powder, add 0.8 mL of deionized water, and stir well to obtain a gel.

[0031] Example 5: Determination of Encapsulation Rate

[0032] Take appropriate amount of Examples 1 to 4 for liquid chromatography analysis; take 10 mg of sample, dissolve in 1 mL of deionized water, dissolve by ultrasonication at room temperature for 10 min, centrifuge at 8000 rpm / min for 15 min, wash the precipitate, centrifuge at 4°C, 8000 g for 15 min, take the precipitate and add 10 mL of methanol to make up the volume, and perform liquid chromatography analysis to determine the content of entrapped allantoin. Calculate the entrapment rate according to the following formula: Encapsulation rate = content of entrapped allantoin / amount of allantoin added * 100%

[0033] HPLC analysis was carried out using Shimadzu high performance liquid chromatography, and the detector was SPD-M20; chromatographic conditions: C18 column (4.6mm*150mm; 5μm), column temperature: 35°C, and the mobile phase was methanol-0.1% formic acid water 1ml / min. The conditions were as follows: time program (gradient elution): 0-5min, 10% methanol, 90% formic acid water; 20min, 100% methanol, 0% formic acid water; 20-27min, 100% methanol, 0% formic acid water.

[0034] Preparation of allantoin standard solution: accurately weigh 0.0053g of allantoin, dissolve it in methanol and dilute it to a 10mL volumetric flask to form a mother solution (530ug / mL), take 0.2, 0.4, 0.8, 1.6, and 3.2mL respectively, dilute it with methanol and dilute it to a 10mL volumetric flask to form a series of standard solutions with concentrations of 10.6, 21.2, 42.2, 84.8, and 169.6ug / mL. Allantoin standard curve: y=51329x+39610, R 2 =0.9995

[0035] Example 6 Wound healing test

[0036] Male SPF Balb / c mice aged 6-7 weeks and weighing 20-25g were selected and purchased from Guangdong Medical Experiment Center. A total of 20 mice were divided into 4 groups. After 3 days of adaptive feeding, the hair on the back of the mice was shaved and 2% sodium sulfide was used for hair removal. The hair removal area was 2cm×4cm. After 2 days of recovery, the back of the mice was modeled using an ultraviolet cross-linking instrument. The UVB irradiation lamp was 15cm away from the back. The back was irradiated (once every other day) and the drug was administered every day according to the grouping and operation method. The experimental period was 21 days, and the dosages were as follows: blank group: n=5, no operation; model group: n=5, irradiation UVB 300mJ / cm2 / time; allantoin group: n=5, irradiation UVB 300mJ / cm2 / time, and application of allantoin drug 100mg / d; Example 2 group: n=5, irradiation UVB 300mJ / cm2 / time, and application of Example 2 drug 100mg / d (alantoin meter). At the end of the experiment, the water loss rate was analyzed using a transcutaneous water loss tester and the back skin of the mice was photographed.

[0037] Parcel rate test results

[0038] Table 1 shows the encapsulation rates of Examples 1 to 4, indicating that the higher the amount of glycolipid used, the higher the encapsulation rate. Figure 1 and Figure 2 The animal inflammation model is modeled by UVB. Example 2, which is wrapped and gelled by the process of the present invention, has better anti-inflammatory and moisturizing effects than allantoin itself under the mouse UVB inflammation model.

[0039] Table 1 Comparison of wrapping rates of different embodiments and comparative examples

[0040] Grouping Packing rate (%) Example 1 73.12％ Example 2 81.98％ Example 3 86.39％ Example 4 90.76％

Claims

1. A method for preparing an external gel containing allantoin liposomes, characterized in that: The method comprises the following steps: step 1: dissolving allantoin in an ethanol aqueous solution, and fully stirring to dissolve to obtain an allantoin ethanol aqueous solution; step 2: adding glycolipid to the allantoin ethanol aqueous solution, fully stirring and maintaining for 30 minutes; step 3: concentrating under reduced pressure at 60° C. until it becomes viscous, adding glycyrrhizic acid ethanol aqueous solution, continuing to concentrate and dry until it becomes solid, and crushing to obtain solid powder; step 4: dissolving the solid powder obtained in step 3 in water to obtain a gel.

2. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: In the allantoin ethanol aqueous solution of step 1, the concentration of allantoin is 1-6 mg / mL, and the volume concentration of ethanol in the ethanol aqueous solution is 20-90%.

3. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: In step 2, the final concentration of glycolipid added is 10-120 mg / mL.

4. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: The concentration of the glycyrrhizic acid ethanol aqueous solution added in step 3 is 20-240 mg / mL.

5. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: The volume concentration of ethanol in the ethanol aqueous solution used in step 3 is 20-90%.

6. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: Step 4: The weight ratio of the solid powder to water is 1:0.5 to 1:

2.

7. The method for preparing an external gel containing allantoin liposomes according to claim 1, characterized in that: The prepared gel is used externally to promote wound healing and moisturize.

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