Diosmin-containing depilatory paste with soothing effect and preparation method thereof

Abstract

The invention belongs to the technical field of cosmetics, and discloses a diosmin-containing depilatory paste with a soothing effect and a preparation method thereof, the depilatory paste comprises the following components by mass: 50-80% of water, 6-15% of fatty alcohol, 3-6% of an emulsifier, 10-25% of an emollient, 3-8% of mercaptoacetate, 0.1-0.4% of a pH regulator, and 0.01-0.1% of diosmin. Diosmin with good alkaline stability is introduced into a depilatory paste system with the pH value of about 12.5, the problem that the activity of a traditional soothing component is reduced in a strong alkaline environment is solved, the skin irritation reaction caused by chemical depilation is effectively relieved, and patch tests prove that the depilatory paste is low in skin irritation, obvious in soothing effect and free of toxic and side effects. The composition is suitable for sensitive skin users and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of cosmetic technology, specifically relating to a hair removal cream containing diosmin with soothing effects and its preparation method. Background Technology

[0002] Depilatory creams are topical cosmetics that remove hair by chemically destroying the keratin structure of hair follicles. They are non-invasive, easy to use, and cause minimal pain, and are widely used for non-physical hair removal in areas such as the underarms, legs, and around the lips. Their main mechanism of action relies on alkaline components (such as sodium hydroxide or potassium hydroxide) in the cream to soften and swell the hair, followed by the use of thioglycolates to break the disulfide bonds in the keratin, causing the hair to break and dissolve, making it easier to remove from the skin. However, commercially available depilatory creams generally have a high degree of irritation. Their alkaline system poses a significant risk of damaging the skin barrier, and common adverse reactions include redness, stinging, burning, and itching, especially for people with sensitive skin. Although some depilatory creams now include traditional soothing ingredients such as purslane extract, aloe vera gel, and calendula, studies have found that these ingredients are prone to structural degradation or inactivation in alkaline environments with a pH above 12, making it difficult for them to exert their soothing effects and affecting the user experience and skin safety.

[0003] With increasing demands for the safety of daily skincare products, developing a cosmetic formula that is both effective at hair removal and capable of providing a soothing effect in a strongly alkaline environment has become a key technological requirement in the current hair removal product industry. Therefore, there is an urgent need to find a functional ingredient that retains stability and soothing activity under alkaline conditions and to establish a matching formulation system to address the issues of high skin irritation and poor soothing effects in hair removal creams, thereby improving the product's gentleness and safety. Summary of the Invention

[0004] To address the shortcomings mentioned in the background art, the present invention aims to provide a hair removal cream containing diosmin with soothing effects and its preparation method. The hair removal cream uses diosmin, which has alkaline stability, as a soothing active substance, combined with hair removal ingredients of thioglycolate, to form a cream formulation. While achieving effective hair removal, it significantly reduces skin discomfort and is suitable for people with sensitive skin.

[0005] The objective of this invention can be achieved through the following technical solutions: Depilatory creams containing diosmin with soothing effects, by weight percentage, include the following components: 50-80% water, 6-15% fatty alcohol, 3-6% emulsifier, 10-25% emollient, 3-8% thioglycolate, 0.1-0.4% pH adjuster, and 0.01-0.1% diosmin.

[0006] More preferably, the fatty alcohol is one or more of stearyl alcohol, cetyl alcohol, myristyl alcohol, and lauryl alcohol.

[0007] More preferably, the emulsifier is one or more of PEG-100 stearate, glyceryl stearate, stearyl alcohol polyether-21, and PEG-20 stearate.

[0008] More preferably, the emollient is one or more of squalane, caprylic / capric triglyceride, mineral oil, hydrogenated polyisobutylene, and polydimethylsiloxane.

[0009] More preferably, the pH adjuster is one or both of sodium hydroxide and potassium hydroxide.

[0010] A method for preparing a hair removal cream containing diosmin with soothing effects includes the following steps: S1. Add water, fatty alcohol, emulsifier and emollient to the emulsification pot in proportion, heat to 75-80℃, and stir to form a homogeneous system. S2. Cool to 40-45℃, then add mercaptoacetate, pH adjuster and diosmin in sequence, and continue to stir until homogeneous; S3. Cool to room temperature to obtain the hair removal cream containing diosmin with soothing effects.

[0011] More preferably, the temperature at which diosmin is added during the preparation process is 40–45°C to avoid high-temperature decomposition or reduced activity.

[0012] More preferably, the hair removal cream is a cream formulation.

[0013] The beneficial effects of this invention are: This invention significantly improves the soothing properties of traditional hair removal creams by introducing diosmin into the formula, effectively solving the technical problem of existing hair removal products causing strong irritation and adverse reactions such as redness, stinging, and itching on sensitive skin. Diosmin, a flavonoid pharmaceutical ingredient with good vascular protection and anti-inflammatory properties, maintains high structural stability and bioactivity under alkaline conditions, unlike commonly used plant extracts (such as purslane and aloe vera) which are easily inactivated in alkaline environments. In this invention, the diosmin content in the formula is scientifically optimized and controlled between 0.01% and 0.1%, ensuring its full soothing effect while avoiding unnecessary burden or side effects caused by excessive raw materials. By rationally combining basic components such as fatty alcohols, emulsifiers, emollients, and pH adjusters, a stable cream formulation system is constructed, allowing the effective hair removal ingredients and soothing factors to work synergistically. Furthermore, the closed patch test showed that the product of this invention did not cause significant skin reactions in the subjects during continuous testing over multiple time periods, fully verifying its low irritation and good skin feel. Attached Figure Description

[0014] The invention will now be further described with reference to the accompanying drawings.

[0015] Figure 1 The graphs show the stability of the active ingredients in the samples of Examples 1-3 and Comparative Examples 1-2. Figure 2 The bar chart shows the comparison of hair removal performance between Examples 1-3 and Comparative Examples 1-2. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 The hair removal cream containing diosmin with soothing effects comprises, by weight percentage, the following components: 73.7% water, 6% fatty alcohol, 3% emulsifier, 10% emollient, 7% thioglycolate, 0.2% pH adjuster, and 0.1% diosmin.

[0018] The preparation steps are as follows: Add 73.7 mL of deionized water to the emulsification pot, turn on the heating system, heat to 75°C, and add 6 g of fatty alcohol (3 g of stearyl alcohol and 3 g of cetyl alcohol), 3 g of emulsifier (1.5 g of PEG-100 stearate and 1.5 g of glyceryl stearate) and 10 g of emollient (5 g of caprylic / capric triglyceride and 5 g of mineral oil) in sequence. Homogenize at 1000 rpm at 75°C for 15 minutes to form a uniform white emulsion paste. Turn off the heating and let it stand to cool naturally to below 45°C. Slowly add 8.75g of calcium mercaptoacetate solution to the cream while maintaining a stirring speed of 600 rpm. Dissolve 0.2g of potassium hydroxide in 1mL of hot water and slowly add it to the system. Adjust the pH of the cream to 12.5±0.2. Add 0.1g of diosmin powder and continue stirring for 10 minutes. Continue stirring and cooling the system to room temperature (approximately 25°C). Defoam and let stand for 30 minutes. Take a sample and observe that the cream has a uniform and delicate appearance, without lumps or layering. This is the hair removal cream containing diosmin with soothing effects.

[0019] Example 2 The hair removal cream containing diosmin with soothing effects comprises, by weight percentage, the following components: 73.7% water, 6% fatty alcohol, 3% emulsifier, 10% emollient, 7% thioglycolate, 0.2% pH adjuster, and 0.05% diosmin.

[0020] The preparation steps are as follows: 73.7 mL of deionized water is added to an emulsifying pot equipped with a stirring system and heated to 75°C. Then, 6.0 g of fatty alcohol, 3.0 g of emulsifier, and 10.0 g of emollient are added sequentially. The temperature is maintained at 75±2°C, and high-speed stirring at 1000 rpm is started to homogenize for 15 minutes to form a uniform emulsion system. Heating is stopped, and the mixture is allowed to cool naturally to 45°C. Stirring continues at 45°C (600 rpm), and 8.75 g of calcium thioglycolate solution is slowly added to ensure uniform dispersion of the hair-removing active ingredients. 0.2 g of potassium hydroxide is dissolved in 1 mL of warm water and slowly added to the system to adjust the pH to 12.5±0.2. 0.05 g of diosmin powder is added, and stirring is maintained for 10 minutes to ensure thorough and uniform dispersion in the system. Heating is stopped, and stirring continues. The mixture is cooled to 25°C, defoamed, and allowed to stand for 30 minutes. A sample is taken and observed; the cream has a uniform and delicate appearance, without lumps or layering. This is the hair-removing cream containing diosmin and possessing a soothing effect.

[0021] Example 3 The hair removal cream containing diosmin with soothing effects comprises, by weight percentage, the following components: 65% water, 10.5% fatty alcohol, 4.5% emulsifier, 17.5% emollient, 5.5% thioglycolate, 0.25% pH adjuster, and 0.055% diosmin.

[0022] The preparation steps are as follows: Add 65.0 mL of deionized water to an emulsifying pot, start the heating system, and raise the temperature to 75℃. Add 10.5 g of fatty alcohol, 4.5 g of emulsifier, and 17.5 g of emollient sequentially. Under constant temperature of 75℃, stir at 1000 rpm for 15 minutes to homogenize and form a white, uniform water-in-oil emulsion system. Turn off the heating device and allow it to cool naturally to 45℃. While maintaining stirring at 600 rpm, slowly add 6.88 g of calcium thioglycolate solution in two batches, with a 2-minute interval between each addition, to prevent violent reactions. Dissolve 0.25 g of potassium hydroxide tablets in 1 mL of warm water and add it dropwise to the emulsion system. Adjust the pH of the system to 12.5 ± 0.2, monitoring it in real time with a pH meter. Add 0.055 g of diosmin powder and continue stirring for 10 minutes to ensure uniform dispersion in the system. Continue stirring and cooling to room temperature. The emulsion system should be a light yellow, soft paste. After stopping stirring, let it stand for 30 minutes. Take a sample and observe that the paste has a uniform and delicate appearance, without lumps or layers. This indicates that it is the hair removal cream containing diosmin with soothing effects.

[0023] Comparative Example 1 The hair removal cream containing diosmin with soothing effects comprises, by weight percentage, the following components: 73.7% water, 6% fatty alcohol, 3% emulsifier, 10% emollient, 7% thioglycolate, 0.2% pH adjuster, and 0.1% purslane extract.

[0024] The preparation steps are as follows: Add 73.7 mL of deionized water to an emulsifying pot, turn on the heating system, and heat to 75°C. Add 6 g of fatty alcohol, 3 g of emulsifier, and 10 g of emollient sequentially. Homogenize at 1000 rpm for 15 minutes at 75°C to form a uniform white emulsion. Turn off the heating and allow it to cool naturally to below 45°C. While stirring at 600 rpm, slowly add 8.75 g of calcium thioglycolate solution in two batches, stirring thoroughly to disperse. Dissolve 0.2 g of potassium hydroxide in 1 mL of warm water and slowly add it dropwise to the system, monitoring the pH in real time to maintain the final pH at 12.5 ± 0.2. Add 0.1 g of purslane extract and continue stirring for 10 minutes to ensure even distribution in the cream. Stop heating, continue stirring, and cool to room temperature. Defoam and allow to stand for 30 minutes. Observe the appearance of the cream; it should be uniform and smooth, without lumps or layering. This is the hair removal cream containing diosmin with soothing effects.

[0025] Comparative Example 2 The hair removal cream containing diosmin with soothing effects comprises, by weight percentage, the following components: 73.7% water, 6% fatty alcohol, 3% polysorbate-80, 10% emollient, 7% thioglycolate, 0.2% pH adjuster, and 0.1% diosmin.

[0026] The preparation steps are as follows: Add 73.7 mL of deionized water to an emulsifying pot and raise the temperature to 75°C. Add 6 g of fatty alcohol, 3 g of polysorbate 80, and 10 g of emollient sequentially. Stir at 1000 rpm for 15 minutes at a constant temperature of 75°C to form a white emulsion. After emulsification, turn off the heating system and allow it to cool naturally to below 45°C. Maintain a stirring speed of 600 rpm at 45°C and slowly add 8.75 g of calcium thioglycolate solution in two batches, with a 2-minute interval between each addition, ensuring thorough and uniform dispersion. Weigh 0.2 g of potassium hydroxide, dissolve it in 1 mL of warm water, and slowly add it dropwise to the emulsion system. Adjust the pH of the paste to 12.5 ± 0.2, monitoring the pH in real time using a pH meter. After the pH stabilizes, add 0.1g of diosmin powder and continue stirring for 10 minutes to fully disperse it. Continue stirring and cool to room temperature (about 25°C). Stop stirring and let it stand for 30 minutes to defoam. Take a sample and observe that the appearance of the cream is uniform and delicate, without lumps or layers. This is the hair removal cream containing diosmin with soothing effects.

[0027] Performance testing 1. Closed patch test A closed patch test was used to compare Examples 1-3 and Comparative Examples 1-2. Thirty healthy volunteers were recruited. Different samples were applied to the inner forearm of each subject, with a dosage of approximately 0.025g each time, and covered with a non-irritating patch for 24 hours. Local skin reactions were observed at 0h, 24h, and 48h after application and graded according to the "Technical Guidelines for Cosmetic Human Patch Testing": Grade 0 (no reaction), Grade 1 (mild erythema), Grade 2 (significant erythema / mild edema), and Grade 3 (significant erythema with moderate to severe edema). The number of Grade 0 reactions in each group and the irritation index were calculated. The results are shown in Table 1 below.

[0028] Table 1 Patch Test Results

[0029] As shown in Table 1, Examples 1-3 exhibited extremely low irritation at all test time points, with a grade 0 reaction rate approaching or reaching 100%, significantly superior to Comparative Examples 1 and 2, which showed grade 1-3 erythema and edema reactions at 24h and 48h, respectively. Diosmin, as a flavonoid component, has good anti-inflammatory and microcirculation-improving effects, stabilizing blood vessel walls and reducing capillary permeability, thereby effectively alleviating the damage to the skin barrier caused by alkaline components. In Comparative Example 2, after replacing the emulsification system with polysorbate-80, the irritation decreased slightly but remained significantly higher than in Examples 1-3, indicating that simply changing the emulsifier is insufficient to reduce irritation. This demonstrates the effectiveness and scientific validity of the present invention in achieving a soothing effect through synergistic effects with diosmin.

[0030] 2. Component stability test Take 5g of samples from Examples 1-3 and Comparative Examples 1 and 2 respectively, and dissolve them in Tris buffer solution at pH 12.5 (store at 37°C in the dark). Samples were taken on days 0, 7, 14, and 30. After centrifugation and dilution, the content of the main soothing active ingredients (flavonoids / phenols in diosmin or purslane extract) was detected by HPLC (high performance liquid chromatography). The residual rate was calculated. Each test was repeated 3 times, and the average value was taken. The results are shown in Table 2 below.

[0031] Table 2 Residual Rate of Active Ingredients

[0032] As shown in Table 2, under alkaline conditions, the residual rate of diosmin in Examples 1-3 was significantly higher than that of the plant extracts in Comparative Examples 1 and 2. After 30 days, the residual rate of the examples remained at approximately 90%, while that of the comparative examples decreased to approximately 55%. This result verifies that the structural stability of diosmin as a soothing active ingredient in an alkaline environment is significantly better than that of flavonoids and phenolic substances in purslane extract. Using the highly stable synthetic monomer diosmin to replace natural extracts avoids oxidative degradation in high pH environments, thus ensuring the long-term effectiveness and functional consistency of the product during actual use. This demonstrates the unique advantages and technological advancements of this invention in soothing skincare formulations.

[0033] 3. Appearance and paste stability test 10g of samples from Examples 1-3 and Comparative Examples 1 and 2 were taken respectively. First, the initial color, uniformity, and tactile properties of the samples were observed at room temperature. Then, the samples were placed in a 45°C constant temperature chamber for accelerated high-temperature testing for 14 days, during which time the samples were periodically checked for adverse phenomena such as layering, clumping, or oil-water separation. After the test, the shear consistency of the samples was measured using a rotational rheometer (shear rate range 10-100 s⁻¹). All samples were tested three times, and the average value was used for evaluation. The results are shown in Table 3 below.

[0034] Table 3. Stability and rheological properties of different sample pastes

[0035] As shown in Table 3, Examples 1-3 all exhibited superior initial texture and high-temperature stability. In particular, Examples 1 and 2 showed no stratification or oil separation under accelerated conditions at 45°C, and demonstrated significant shear thinning performance, indicating that the emulsion system was stable and suitable for practical use. In contrast, Comparative Examples 1 and 2 showed severe stratification, oil-water separation, and low shear response, indicating that traditional formulations are difficult to maintain a homogeneous state under high temperatures or long-term storage. This difference is attributed to the specific emulsifier and polyol synergistic system used in this invention, as well as the interfacial synergistic effect between diosmin and the plant matrix, which improved the micellar stability and rheological properties of the system.

[0036] 4. Hair removal effect test The test subjects were volunteers' inner calf areas. After shaving, the area was left to rest for 48 hours to allow for natural hair growth. Each sample (Examples 1-3, Comparative Examples 1-2) was evenly applied to a designated area (approximately 3×5 cm², 1 mm thick). After resting for 10 minutes, hair removal was performed using a standard scraper at a constant angle and pressure. High-resolution images of the sample areas were recorded after hair removal. Image analysis software was used to calculate the percentage of hair removed (i.e., the percentage of the total test area where hair was completely removed). Simultaneously, the number of residual hairs per unit area (1 cm²) was counted using an optical magnifying glass. Each test was repeated three times, and the average value was taken. The results are shown in Table 4 below.

[0037] Table 4 Comparison of hair removal performance

[0038] As shown in Table 4, the hair removal area ratio of Examples 1-3 was significantly higher than that of the comparative examples, and the number of residual hairs was also less. This superior effect is attributed to the introduced dual-functional structural system. On the one hand, the synergistic penetration mechanism of diosmin helps to soften the keratin structure around the hair follicle, improving the efficiency of the hair removal active ingredients on the hair follicle. On the other hand, the emulsification system with a specific structure and skin adhesion aid enhance the adhesion and film-forming uniformity of the ointment, allowing the hair removal ingredients to be released evenly and stably and fully act on the target area, thereby achieving a more thorough, gentle, and low-residue hair removal effect, which is superior to the comparative examples that did not introduce this structure or changed the emulsifier.

[0039] 5. Film-forming properties and adhesion tests Each group of samples (Examples 1-3, Comparative Examples 1-2) was uniformly coated onto the surface of the artificial skin model (approximately 1 mm thick) and dried at a constant temperature (25°C) for 30 minutes to form a preliminary dry film. Subsequently, the peel adhesion strength (unit: N / cm) between the film layer and the skin model was measured using a 180° peel tester at a speed of 100 mm / min. The uniformity, integrity, and presence of sagging, breakage, or peeling of the film layer were recorded and graded (1-5, with 5 being the best). The results are shown in Table 5 below.

[0040] Table 5. Results of film-forming properties and adhesion.

[0041] Table 5 shows that introducing bioadhesive natural colloids and film-forming aids into the conventional hair removal system significantly improves the uniformity and adhesion strength of the ointment on the skin surface. Test results indicate that Examples 1-3 all exhibit excellent peel adhesion strength (≥1.95 N / cm) and high film integrity scores (4-5 levels), demonstrating that the formulation in this invention helps form a stable, continuous, and uniform film on the skin surface, significantly reducing sagging and shedding during use, and facilitating the full action of the active ingredients and enhancing the hair removal effect. In contrast, Comparative Examples 1 and 2 lack synergistic structural components or did not use film-forming aids, resulting in low adhesion strength, incomplete film layers, and a tendency to peel and crack.

[0042] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A depilatory cream having soothing efficacy containing dioxymatin, characterized in that, By mass percentage, it comprises the following components: water 50-80%, fatty alcohol 6-15%, emulsifier 3-6%, emollient 10-25%, mercaptoacetate 3-8%, pH regulator 0.1-0.4%, diosmin 0.01-0.1%.

2. The soothing depilatory cream containing diosmin according to claim 1, characterized in that, The fatty alcohol is one or more of stearyl alcohol, cetyl alcohol, myristyl alcohol, lauryl alcohol.

3. The soothing depilatory cream containing diosmin according to claim 1, characterized in that, The emulsifier is one or more of PEG-100 stearate, glyceryl stearate, steareth-21, PEG-20 stearate.

4. The soothing depilatory paste containing diosmin according to claim 1, characterized in that, The emollient is one or more of squalane, caprylic / capric triglyceride, mineral oil, hydrogenated polyisobutene, dimethicone.

5. The soothing depilatory cream containing diosmin according to claim 1, characterized in that, The pH regulator is one or both of sodium hydroxide and potassium hydroxide.

6. Process for the preparation of a depilatory cream with soothing effect containing dioxymatin, the depilatory cream with soothing effect containing dioxymatin being as claimed in any one of claims 1 to 5, characterised in that, It comprises the following steps: S1, add water, fatty alcohol, emulsifier and emollient in proportion into an emulsifying kettle, heat to 75-80℃, and mix to form a homogeneous system under stirring; S2, cool to 40-45℃, and then add mercaptoacetate, pH regulator and diosmin in sequence, and continue to stir until uniform; S3, cool to room temperature to obtain the diosmin-containing soothing depilatory cream.

7. The method of preparing the dioxetane-containing soothing depilatory paste according to claim 7, characterized by, The diosmin is added at a temperature of 40-45℃ in the preparation process to avoid decomposition or activity reduction at high temperature.

8. The dioxetane-containing soothing depilatory cream of claim 1, wherein, The depilatory cream is in the form of cream.

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