External cream for directionally delivering tranexamic acid to epidermal layer and preparation method thereof

Abstract

The invention discloses external emulsifiable paste for directionally delivering tranexamic acid to an epidermal layer, which is prepared from the following raw materials in percentage by weight: 1-15% of tranexamic acid, 0.5-7% of alpha-arbutin, 0.3-4% of edetate disodium, 1-5% of azone, 1-5% of sodium dodecyl benzene sulfonate and the balance of water. The skin care product is prepared from, by weight, 0.1%-2% of salicylic acid, 1%-10% of glycerin, 2%-15% of propylene glycol, 0.1%-4% of tween-80 or 0.4%-2% of sorbitan oleate, 0.5%-5% of alpha-tocopherol, 0.5%-5% of diisostearyl alcohol malate, 0.5%-6% of soybean phospholipid, 1%-10% of glycerin monostearate, 0.5%-10% of tetradecanol, 0.02%-0.1% of propyl hydroxybenzoate, 1%-10% of stearic acid, 0.5%-6% of stearyl alcohol and the balance water. Meanwhile, the invention also discloses a preparation method, experiments show that the external cream prepared by the invention has strong capacity of delivering tranexamic acid to the epidermal layer and can ensure that the tranexamic acid can be quickly absorbed by cells to take effect, and the defect that tranexamic acid is difficult to pass through skin cuticle obstacles due to strong hydrophilicity is overcome.

Description

Technical Field

[0001] The invention specifically relates to an external cream for targeted delivery of tranexamic acid to the epidermis and a preparation method thereof. Background Art

[0002] The factors that affect skin color are numerous and complex, covering the external environment, genetic background, hormone levels in the body, and personal lifestyle. For example, long-term exposure to ultraviolet rays, adverse climatic conditions, pollutants in the air, the effects of ionizing radiation, frequent late nights, stress, smoking habits, unreasonable diet structure, hormone imbalance, and excessive pigmentation caused by genetics can all cause dullness, spots, wrinkles, or dryness on the skin. The main determinant of skin color is the amount of melanin. Melanin is a biological pigment that can be dissolved in alkaline solutions but not in water. It is a type of protein derivative. It is produced by melanosomes formed in melanocytes located in the basal layer of the skin, and migrates to the epidermis with the development of keratinocytes and eventually falls off. Therefore, the depth of a person's skin color is closely related to the amount and distribution of melanin in the body. There are two main types of melanin in the human body: eumelanin and pheomelanin. The amount and ratio of these two pigments in the epidermis determine the skin color of the person. Generally speaking, the lower the ratio, the lighter the skin color. The synthesis of melanin begins with tyrosine. In this process, several key enzymes such as tyrosinase (TYR), tyrosine-related protein-2 (TRP2) and tyrosine-related protein-1 (TRP1) play an important role, among which TYR is particularly important. In addition, endocrine status, dopamine levels and trace elements (such as copper ions) can also affect the production of melanin. Inhibiting tyrosinase activity or interfering with the reaction pathway in which it participates is one of the effective means to achieve skin whitening. Glutathione (GSH), as a substance containing a thiol tripeptide structure, can reduce the divalent copper in tyrosinase to a monovalent copper form, thereby preventing the formation of melanin. Lei Tiechi et al.'s research showed that hydroquinone exhibited a biphasic regulatory effect on B16F10 mouse tyrosinase cultured in vitro: at lower concentrations (0.1-0.5 μmol / L), it could reduce the enzyme activity and melanin content; at higher concentrations (1-10 μmol / L), it would slightly increase the enzyme activity. Nevertheless, considering the potential toxicity of hydroquinone to the skin, people have been increasingly inclined to use natural plant extracts with whitening effects as alternatives in recent years. For example, licorice, mulberry leaves and aloe vera have all been shown to effectively inhibit tyrosinase activity. In addition to directly acting on the melanin synthesis pathway, some ingredients can also achieve a whitening effect by reducing the transport of formed melanin to the epidermis. For example, a study by Hakozaki et al. showed that people who applied a moisturizer containing 5% niacinamide (ie, vitamin B3) on their faces performed better in improving pigmentation than individuals who only used products containing 2% of this ingredient. Niacinamide can prevent melanin particles from entering the upper layer of the skin, thereby achieving the effect of brightening the skin. Another commonly used whitening ingredient, tranexamic acid, slows down the rate of melanin synthesis by changing the relationship between melanocytes and surrounding keratinocytes.Although hydroquinone, which was widely used in history, is also an effective tyrosinase inhibitor, it is no longer recommended as a cosmetic raw material because it may cause serious side effects. In contrast, β-arbutin and its isomer α-arbutin have become one of the most popular whitening additives today because they are relatively mild and harmless. In particular, the latter has a much higher inhibitory efficiency than the former because it binds more tightly to human-derived tyrosinase. Currently, the only product on the market approved by the US Food and Drug Administration (FDA) for the treatment of various pigmentation symptoms (including melasma) is a compound preparation consisting of 4% hydroquinone, 0.01% fluocinolone and 0.05% retinoic acid. However, this combination therapy is not suitable for long-term use by everyone because each individual ingredient may cause a series of adverse reactions. For example, hydroquinone may cause contact dermatitis or even permanent white spots; retinoic acid can make the skin extremely sensitive and dry; and the continuous use of glucocorticoids can cause problems such as facial atrophy. In view of these limitations, non-invasive laser therapy has begun to receive more attention. In particular, the 1550-nanometer wavelength Fractional laser is one of the technologies certified by the FDA for improving the appearance of melasma. Fractional laser uses a segmented treatment strategy to create tiny trauma points on the skin surface to stimulate the regeneration of deep collagen fibers, but this also means that the postoperative recovery period is long and is accompanied by temporary skin problems such as scabs and desquamation. In contrast, oral or topical application of tranexamic acid is considered to be a safer and more effective method for removing spots. Tranexamic acid was originally developed as a hemostatic drug, and later it was found that it also has the effect of reducing melasma. Studies have shown that even short-term and low-dose administration of tranexamic acid can significantly reduce spots. This is because tranexamic acid can inhibit the work of the plasmin-plasminogen system, thereby reducing the production of related factors that promote melanin production, such as prostaglandins (PG). At the same time, because its chemical structure is similar to tyrosine, it can also prevent excessive melanin formation by competitively inhibiting the activity of tyrosinase.

[0003] Tranexamic acid can be administered orally, by injection, or by topical application, but there is a recurrence rate for the treatment of melasma with oral tranexamic acid. Local microinjection of tranexamic acid can cause local transient discomfort and mild wheals, so topical application has a high biosafety and is convenient for patients to use and is gaining more and more attention. However, due to the strong hydrophilicity of tranexamic acid, it is difficult to pass through the stratum corneum barrier of the skin, and the drug needs to be encapsulated by permeation-enhancing technologies such as liposomes to promote transdermal permeability. Summary of the invention

[0004] The object of the present invention is to provide an external cream for targeted delivery of tranexamic acid to the epidermis, and providing a preparation method thereof is the second object of the present invention.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme:

[0006] In a first aspect, the present invention provides an external cream for targeted delivery of tranexamic acid to the epidermis, wherein the cream is made of the following raw materials in percentage by weight: 1-15% tranexamic acid, 0.5-7% α-arbutin, 0.3-4% edetate disodium, 1-5% laurocapram, 0.1-2% salicylic acid, 1-10% glycerol, 2-15% propylene glycol, 0.1%-4% Tween-80 or 0.4%-2% sorbitan oleate, 0.5-5% α-tocopherol, 0.5-5% diisostearyl malate, 0.5-6% soybean lecithin, 1-10% glyceryl monostearate, 0.5-10% tetradecanol, 0.02-0.1% propylparaben, 1%-10% stearic acid, 0.5-6% stearyl alcohol, and the remainder is water.

[0007] As further preferred embodiment of the present invention, the cream is made of the following raw materials in percentage by weight: 3-8% tranexamic acid, 2% α-arbutin, 2% disodium edetate, 2% laurocapram, 0.3% salicylic acid, 1-3% glycerol, 8% propylene glycol, 0.5% sorbitan oleate or 0.5% Tween-80, 3% α-tocopherol, 2-3% diisostearyl malate, 1.5-3% soybean lecithin, 2.6-3% glyceryl monostearate, 2.6-3% tetradecanol, 0.1% propylparaben, 3-4% stearic acid, 1-1.1% stearyl alcohol, and the rest is water.

[0008] In a second aspect, the present invention further discloses a method for preparing an external cream for targeted delivery of tranexamic acid to the epidermis, comprising the following steps:

[0009] S1, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase;

[0010] S2, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol, sorbitan oleate and salicylic acid in a water bath at 70°C to form an oil phase;

[0011] S3, adding laurocapram to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 min to obtain the cream.

[0012] As another technical solution of the present invention, the present invention also provides a method for preparing the topical cream for targeted delivery of tranexamic acid to the epidermis when the emulsifier is Tween-80, comprising the following steps:

[0013] S11, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase;

[0014] S12, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol and salicylic acid in a water bath at 70° C. to form an oil phase;

[0015] S13, adding laurocapram and Tween-80 to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 minutes to obtain a cream.

[0016] In the present invention, the roles played by each component in the present invention are:

[0017] The active ingredients used to exert the effect are tranexamic acid and α-arbutin; the penetration enhancer is a combination of edetate disodium, laurocapron and salicylic acid, among which edetate disodium can adsorb metal ions, making other active ingredients more easily absorbed by the skin, thereby enhancing the penetration of skin care products and improving the effect of the product. Azone can interact with lipids in the stratum corneum, making the side chains more disordered, resulting in enhanced lipid fluidity and reducing the resistance to drug transdermal absorption; in addition, azone can also cause the keratin in the stratum corneum to transform from the α-helical structure to the β-folded structure and irregular curling structure, and the stacking structure becomes loose, reducing the barrier effect of drug transdermal absorption and achieving a penetration-enhancing effect. Salicylic acid can dissolve or soften the stratum corneum, making the substance easier to penetrate. The moisturizer is a combination of glycerin and propylene glycol. Glycerin is the most widely used natural moisturizer, but its texture is sticky and it will feel warm when applied. From the perspective of skin feel design and moisturizing effect analysis, the added content cannot be too high. Adding propylene glycol with low viscosity can make the skin feel relatively more refreshing; the cream base is a combination of stearic acid and stearyl alcohol; the emulsifier is Tween-80 or sorbitan oleate; the antioxidant is α-tocopherol; the thickener is diisostearyl malate; the penetration aid is soybean lecithin; the auxiliary emulsifier is glyceryl monostearate; the emollient is tetradecyl alcohol; and the antibacterial agent is propylparaben.

[0018] Compared with the prior art, the present invention has the following technical effects:

[0019] The external cream prepared by the invention has a strong ability to deliver tranexamic acid to the epidermis and can ensure that it is quickly absorbed by cells and takes effect, thereby overcoming the defect that tranexamic acid is difficult to pass through the stratum corneum of the skin due to its strong hydrophilicity. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are used to illustrate the present invention, rather than to limit the present invention. The room temperature described in the present invention refers to 20-30°C, and for the embodiments of the present invention, it is specifically 25-28°C.

[0021] Example 1

[0022] This example provides cream preparation samples 1-6 for targeted delivery of tranexamic acid to the epidermis of the skin. The material components of samples 1-6 are shown in Table 1.

[0023] Table 1:

[0024]

[0025]

[0026] The preparation method of samples 1-6 comprises the following steps:

[0027] S1, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase;

[0028] S2, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol, sorbitan oleate and salicylic acid in a water bath at 70°C to form an oil phase;

[0029] S3, adding laurocapram to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 min to obtain an emulsion.

[0030] Example 2

[0031] This example provides cream preparation samples 7-12 for targeted delivery of tranexamic acid to the epidermis of the skin. The material components of samples 1-6 are shown in Table 2.

[0032] Table 2:

[0033]

[0034]

[0035] The preparation method of samples 7-12 of this embodiment comprises the following steps:

[0036] S11, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase;

[0037] S12, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol and salicylic acid in a water bath at 70° C. to form an oil phase;

[0038] S13, adding laurocapram and Tween-80 to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 minutes to obtain the cream.

[0039] Animal experiments

[0040] Samples 1-12 were scored in accordance with the "T / GDCA 003-2020 General Rules for Sensory Evaluation of Cosmetics", and sample 5 scored the highest. Sample 5 was selected for the next animal experiment.

[0041] 1. Experimental methods:

[0042] Compared with human skin, the skin of Bama miniature pigs is more similar to human skin in morphology, anatomy and physiology, and its skin permeability is similar to that of human skin. Miniature pigs are generally selected for related experiments in transdermal drug delivery projects. Bama miniature pigs have rich background information and are in sufficient supply. Therefore, Bama miniature pigs were selected as test animals in this experiment. Four female Bama miniature pigs were randomly divided into groups according to body weight one day before drug administration. The specific information of animal grouping and drug administration is shown in Table 3.

[0043] Table 3:

[0044]

[0045] Note: The first digit of the animal number represents the sex (1 for male, 2 for female); the second digit represents the group (1 for the first group, 2 for the second group, and so on); the last two digits represent the animal sequence number.

[0046] Pig total body surface area (cm 2 )=0.1004×BW (2 / 3) (kg)×10000.

[0047] 2. Steps for drug administration on the skin surface

[0048] 1) Before administration, the animal's back should be depilated. The depilated area should be larger than the administration area. The skin should be cleaned with saline and dried with absorbent paper. The skin should be checked for damage and photographed for preservation.

[0049] 2) On the day of administration, the hair was trimmed appropriately and the skin was cleaned with saline solution, and then dried with absorbent paper. Based on the body weight before administration, the administration area was marked with a marker. The administration area (cm 2 ) = Pig body surface area (cm 2)×0.03 (i.e. 3% of the surface area).

[0050] 3) Calculate the amount of test substance required for application according to the animal's administration area (the allowable weighing error is ±5% of the theoretical amount), apply the test substance to the skin at the administration site, and after applying it evenly, allow the skin to absorb it naturally for 1 hour (±10 minutes). Then cut a gauze of appropriate size to cover the administration site and fix the entire administration site with medical tape.

[0051] 4) 6 hours after administration (the 3-hour distribution group was cleaned before collecting tissue samples), the tape and gauze covering the administration site were cut with scissors to expose the administration site, and the administration site was cleaned with gauze dipped in physiological saline and a scraper or a flat cotton swab in an S-shaped cleaning route, 5 times for each route.

[0052] 2. Tissue sample collection and processing

[0053] At the corresponding time point, about 1.5 mL of whole blood was collected from each group of animals into an anticoagulant blood collection tube containing EDTA-K2, gently inverted and mixed, and then temporarily placed on wet ice. Within 2 hours, the blood was centrifuged at 4°C and 2600g for 10 minutes to obtain plasma, which was then stored in a refrigerator below -60°C. Tissue sample collection is shown in Table 4.

[0054] Table 4:

[0055]

[0056] After complete blood collection, 5 mg / kg of Shutai 50 was injected intravenously with a dosing volume of 0.1 mL / kg, combined with 2 mg / kg of xylazine hydrochloride injection injected intramuscularly with a dosing volume of 0.04 mL / kg. After the animals were deeply anesthetized, they were euthanized by arterial bleeding. After the death of the animals was confirmed, the tape and gauze (if necessary) wrapped around the dosing site were cut open to expose the dosing site. Tissue samples were collected according to the following steps and stored in a refrigerator below -60°C within 2 hours after collection.

[0057] 1) Use pre-cut (3cm*3cm) transparent tape to stick the stratum corneum of the pre-marked administration sites B1-B5, repeat 15 times / site, replace with new tape each time, collect all tapes into a suitable plastic bottle, and add 100mL 50% acetonitrile into the plastic bottle;

[0058] 2) Cut the complete tissues (including the skin layer, subcutaneous fat layer and muscle layer) of the administration sites A1-A5 longitudinally in sequence, cut a piece of plastic wrap of appropriate size, lay it flat with the skin layer of the tissue facing down on the plastic wrap, try not to move the tissue after placing it, then carefully wrap the plastic wrap on the other sides, wrap the entire tissue, mark it, place the skin layer of the tissue facing down in a sample box, place it in a dry ice box, and take it out after the tissue is frozen to a certain degree;

[0059] 3) Carefully remove the plastic wrap, place the collected tissue samples of A1-A5 on a pressing plate with clean filter paper, and use a knife to trim the tissues of A1-A5 until the target tissues B1-B5 are obtained. Each time the knife touches the tissue, it must be cleaned with 75% medical alcohol or replaced with a new knife. After each cut, move the tissue to the untouched filter paper surface. If necessary, replace the new filter paper to prevent contamination of the sample; after completion, wear clean gloves, cut the epidermis, dermis, subcutaneous fat layer and muscle layer of the B1-B5 tissue (the fat layer may be associated with excess muscle), which need to be peeled off and stored separately, and the tissues corresponding to the administration site B1-B5 are combined and transferred to a pre-weighed centrifuge tube. After completion, weigh and record the total weight.

[0060] 3. Analysis of Biological Samples

[0061] The LC-MS / MS method was used to quantitatively detect the concentration of tranexamic acid in plasma and tissue homogenate samples of Bama miniature pigs. The test results are shown in Table 5.

[0062] Table 5:

[0063]

[0064]

[0065] As can be seen from Table 5, after applying 3h, the active ingredient tranexamic acid of sample 5 has achieved high concentration enrichment in the epidermis where melanocytes are located, and only a small amount of tranexamic acid is distributed in the stratum corneum, which shows that the cream can well achieve the enrichment of the active ingredient in the target position. At 6h, most of the tranexamic acid has played a role and it can be seen that the content of tranexamic acid in the epidermis has decreased by 66%. By 24h, the content of tranexamic acid in the epidermis is reduced to 16% at 3h, while the content in the dermis has hardly increased, indicating that tranexamic acid continues to play a role within 24h. By 48h, the content of tranexamic acid in the epidermis is not much different from that at 24h. In summary, it can be seen that the sample 5 cream has a strong ability to deliver tranexamic acid to the epidermis and can ensure that it is quickly absorbed by cells and takes effect.

[0066] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any person skilled in the art can use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. An external cream for targeted delivery of tranexamic acid to the epidermis, characterized in that: The cream is prepared from the following raw materials in percentage by weight: 1-15% of tranexamic acid, 0.5-7% of α-arbutin, 0.3-4% of disodium edetate, 1-5% of laurocapram, 0.1-2% of salicylic acid, 1-10% of glycerol, 2-15% of propylene glycol, 0.1%-4% of Tween-80 or 0.4%-2% of sorbitan oleate, 0.5-5% of α-tocopherol, 0.5-5% of diisostearyl malate, 0.5-6% of soybean lecithin, 1-10% of glyceryl monostearate, 0.5-10% of tetradecanol, 0.02-0.1% of propylparaben, 1%-10% of stearic acid, 0.5-6% of stearyl alcohol, and the rest is water.

2. The topical cream for targeted delivery of tranexamic acid to the epidermis according to claim 1, characterized in that The cream is prepared from the following raw materials in percentage by weight: 3-8% tranexamic acid, 2% α-arbutin, 2% disodium edetate, 2% laurocapram, 0.3% salicylic acid, 1-3% glycerol, 8% propylene glycol, 0.5% sorbitan oleate or 0.5% Tween-80, 3% α-tocopherol, 2-3% diisostearyl malate, 1.5-3% soybean lecithin, 2.6-3% glyceryl monostearate, 2.6-3% tetradecanol, 0.1% propylparaben, 3-4% stearic acid, 1-1.1% stearyl alcohol, and the rest is water.

3. A method for preparing an external cream for targeted delivery of tranexamic acid to the epidermis according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase; S2, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol, sorbitan oleate and salicylic acid in a water bath at 70°C to form an oil phase; S3, adding laurocapram to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 min to obtain the cream.

4. A method for preparing an external cream for targeted delivery of tranexamic acid to the epidermis according to any one of claims 1 to 2, characterized in that: The following steps are involved: S11, dissolving tranexamic acid, α-arbutin, disodium edetate, glycerol and propylene glycol in water at room temperature as an aqueous phase; S12, melt the prescribed amount of propylparaben, α-tocopherol, diisostearate malate, stearic acid, soybean lecithin, glyceryl monostearate, stearyl alcohol, tetradecyl alcohol and salicylic acid in a water bath at 70° C. to form an oil phase; S13, adding laurocapram and Tween-80 to the aqueous phase, and then performing high pressure homogenization at a speed of 15000 rpm and adding the oil phase, and after the addition, continuing homogenization for 20 minutes to obtain a cream.

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