Whitening composition, modified glutathione and preparation method thereof

Abstract

The invention relates to a whitening composition, modified glutathione and a preparation method thereof. The preparation method of the modified glutathione specifically comprises the following steps: 1) obtaining a liposome suspension, performing ultrasonic dispersion, mixing the liposome suspension with hyaluronidase and a cross-linking agent, and stirring to obtain a HAase-Lip suspension; and 2) mixing glutathione with the HAase-Lip suspension, carrying out a stirring reaction, and carrying out ultrasonic treatment to obtain the glutathione-Lip composite material. The phospholipid bilayer vesicle structure of Lip can form a physical barrier, so that the efficacy attenuation is greatly delayed. Meanwhile, a skin-like lipid structure of Lip can be fused with a cuticle lipid bilayer, the nanoscale particle size of Lip can be matched with the cuticle gap size, and Lip penetrates through the cuticle by means of the permeation mechanism of Lip; on the other hand, HAase has the capability of degrading hyaluronic acid on the surface layer of the skin, assists Lip and internal GSH to permeate into the deep layer of the epidermis, and reduces the damage of transdermal penetration to the skin barrier.

Description

Technical Field

[0001] This invention relates to the field of cosmetic formulation technology, and particularly to whitening compositions, modified glutathione, and methods for their preparation. Background Technology

[0002] With consumers' ever-increasing demand for skin whitening and their growing awareness of the efficacy and safety of skincare products, the development of highly effective, stable, and gentle whitening active ingredients has become a key research focus in the cosmetics industry. Excessive melanin deposition is the core cause of dull skin and age spots. Its formation process requires tyrosinase to catalyze the conversion of tyrosine into dopa and dopaquinone, which eventually polymerizes into melanin. The accumulation of reactive oxygen species (ROS) caused by oxidative stress further accelerates this process, while also damaging the skin barrier and exacerbating pigmentation.

[0003] Glutathione (GSH), an endogenous tripeptide compound, is a recognized ideal active ingredient with both antioxidant and whitening effects. Its mechanism of action is clearly defined: on the one hand, the sulfhydryl group (-SH) in the glutathione molecule can directly scavenge ROS in the skin, inhibiting the stimulation of melanocytes by oxidative stress and reducing upstream factors in melanin synthesis; on the other hand, glutathione can bind to copper ions at the active site of tyrosinase, competitively blocking the catalytic pathway of tyrosine, while accelerating the reduction and decomposition of already formed melanin, achieving a full-chain whitening effect from source inhibition to later fading. Furthermore, as an endogenous component, glutathione has excellent biocompatibility and is less irritating than traditional whitening ingredients such as hydroquinone and retinoic acid, making it suitable for sensitive skin and other special skin types. Therefore, it has extremely high application potential in the field of whitening skincare products.

[0004] However, the practical application of glutathione in skin whitening compositions has long been limited by two core technological bottlenecks, which severely restrict its efficacy: 1) Extremely poor stability and easy oxidation and inactivation: The core efficacy of glutathione relies on the free thiol group in the molecule. This group is chemically extremely reactive and readily reacts with oxygen, metal ions, and other components in the composition, leading to oxidation and inactivation. In conventional whitening composition systems, on the one hand, oxygen encountered during production, storage, and use oxidizes the thiol group into disulfide bonds, forming inactive oxidized glutathione (GSSG), resulting in a half-life of less than 7 days at room temperature and severe efficacy degradation during the product's shelf life. On the other hand, unavoidable trace amounts of iron, copper, and other metal ions in the composition catalyze the oxidation reaction of the thiol group, accelerating glutathione degradation. Furthermore, if preservatives, fragrances, and other ingredients are added to the composition, the oxidative properties of some components will further exacerbate the inactivation of glutathione, resulting in the actual efficacy of the final product being far lower than the theoretical value. In existing technologies, although there have been attempts to delay the oxidation of glutathione by adding antioxidants such as sulfites, sulfite-based ingredients are prone to causing skin sensitization and can only delay oxidation temporarily, failing to fundamentally solve the stability problem of glutathione.

[0005] 2) Extremely low transdermal absorption efficiency, making it difficult to penetrate the skin barrier. The stratum corneum is the main barrier for active ingredients to penetrate the skin, and its dense lipid bilayer structure results in extremely low permeability to water-soluble components. Glutathione is a highly water-soluble polar molecule with a molecular weight of approximately 307 Da and lacks lipid-soluble groups. In conventional whitening compositions, over 90% of glutathione can only remain on the skin surface and cannot penetrate the stratum corneum to reach melanocytes in the epidermal basal layer or oxidative stress sites in the dermis. In existing technologies, some solutions improve permeability by adding transdermal enhancers such as ethanol and penetration-enhancing peptides. However, ethanol easily damages the skin barrier, causing dryness and redness, while penetration-enhancing peptides are expensive and have poor compatibility with glutathione. Other solutions use liposome encapsulation technology to improve transdermal permeability, but ordinary liposomes lack targeting and tend to diffuse in the superficial layers of the skin after transdermal penetration, failing to accurately accumulate at melanin-producing sites and still struggling to achieve highly effective whitening effects.

[0006] In summary, although glutathione has excellent whitening and antioxidant potential, existing whitening compositions cannot solve its key defects of easy oxidation and inactivation and low transdermal efficiency, which limits its efficacy in practical applications. Summary of the Invention

[0007] The first aspect of this invention is to provide a method for preparing modified glutathione, specifically comprising the following steps: 1) Obtain a liposome suspension, disperse it by ultrasonication, mix it with hyaluronidase (HAase) and a cross-linking agent, and stir to obtain a HAase-Lip suspension; 2) Glutathione (GSH) is mixed with the HAase-Lip suspension, stirred and reacted, and then sonicated to obtain the product.

[0008] Lip's phospholipid bilayer vesicle structure forms a physical barrier, encapsulating GSH within the aqueous phase. This isolates it from external oxygen, metal ions, and preservatives, fragrances, and other ingredients in cosmetic systems, preventing the oxidation of thiol groups (-SH) in GSH molecules into inactive disulfide bonds and significantly delaying its efficacy decay. Simultaneously, Lip's skin-like lipid structure can fuse with the stratum corneum lipid bilayer. Its nanoscale particle size adapts to the interstitial space size of the stratum corneum, allowing it to penetrate the stratum corneum via its permeation mechanism, achieving a 3-5 times higher transdermal efficiency compared to free GSH. Furthermore, HAase itself has the ability to degrade hyaluronic acid on the skin's surface, temporarily opening molecular channels in the stratum corneum and facilitating the penetration of Lip and its internal GSH into the deeper layers of the epidermis. The small-molecule hyaluronic acid produced by HAase degradation also forms a moisturizing film on the skin surface, reducing moisture loss during penetration and minimizing damage to the skin barrier caused by transdermal penetration.

[0009] In a further preferred embodiment, the raw materials of the liposome suspension include hydrogenated lecithin (HSPC), cholesterol (Chol), and dipalmitoylphosphatidylethanolamine-polyethylene glycol (DPPE-PEG); preferably, by weight, the HSPC comprises 5-7 parts, the Chol comprises 2-3 parts, and the DPPE-PEG comprises 1-2 parts. The HSPC is the core film-forming material, exhibiting high biocompatibility and strong oxidative stability; the Chol can regulate the fluidity and rigidity of the membrane, compensating for the excessive strength of the HSPC membrane structure; the DPPE-PEG can form a hydration film on the liposome surface, improving water dispersibility and prolonging circulation / retention time. Together, these three components constitute a stable liposome membrane framework.

[0010] In a further preferred embodiment, the solvent for the Lip suspension is chloroform.

[0011] In a further preferred embodiment, the ultrasonic dispersion in step 1) has a power of 250-300 W and a duration of 2-5 minutes; the ultrasonic treatment in step 2) has a power of 150-200 W and a duration of 10-15 minutes. The power and duration required for the two ultrasonic treatments are different because the core objective in step 1) is to construct the basic structure of the HAase-Lip suspension, which requires strong ultrasonic energy to achieve Lip dispersion and ligand anchoring; the core objective in step 2) is to gently encapsulate GSH, which requires low power and long-term ultrasonic treatment to ensure the stability of the active ingredient while improving encapsulation efficiency.

[0012] In a further preferred embodiment, the concentration of HAase is 1~5 mg / mL; the mass ratio of DPPE-PEG to HAase is (10~20):1.

[0013] In a further preferred embodiment, the crosslinking agent is polyethylene glycol diacrylate (PEG-DA), accounting for 0.5-1% of the HAase-Lip suspension by mass. PEG-DA has advantages such as high biocompatibility, no risk of sensitization, and the ability of PEG chains to enhance the water dispersibility of liposomes.

[0014] In a further preferred embodiment, trehalose is added simultaneously with HAase in step 1), wherein the mass ratio of trehalose is 1-2% of the HAase-Lip suspension. Trehalose is a small-molecule natural moisturizer that can bind with hydrogenated lecithin through hydrogen bonds to form a hydrophilic protective shell on the Lip surface. This complex has no potential risks associated with synthetic polymers, exhibits extremely high biocompatibility, and trehalose can simultaneously protect the thiol groups of GSH from oxidation, thus balancing stability and efficacy, making it suitable for liposome systems in sensitive skin care products.

[0015] In a further preferred embodiment, the mass ratio of GSH to the HAase-Lip suspension in step 2) is (20~50):1. The amount of GSH added needs to be within the saturation encapsulation range of the liposomes. If it exceeds the upper limit of the liposome vesicle loading, it will lead to a large amount of free GSH residue, increasing the difficulty of purification. Too high a ratio can easily cause liposome membrane rupture, while too low a ratio will not achieve effective efficacy. The preferred ratio of (20~30):1 can balance stability and efficacy.

[0016] A second aspect of the present invention is to provide a modified glutathione prepared by the preparation method described in the first aspect of the present invention.

[0017] A third aspect of the present invention is to provide a skin-whitening composition containing the modified glutathione described in the second aspect of the present invention. The raw materials of the skin-whitening composition include carbomer, trehalose, betaine, allantoin, glyceryl polyether-26, sodium EDTA-2, 1,3-butanediol, triethanolamine (TEA), 1,2-hexanediol, phenoxyethanol, glycerol, carnosine, and the modified glutathione.

[0018] In a further preferred embodiment, the raw materials also include flavorings and / or compatibilizers.

[0019] In a further preferred embodiment, the raw materials of the whitening composition, calculated by weight percentage, include: Carbomer 0.20~0.25%; Trehalose 1.00~1.20%; Betaine 1.00~1.50%; Allantoin 0.10~0.12%; Glyceryl polyether-26 2.00~3.00%; EDTA-2Na 0.02~0.03%; 1,3-Butanediol 4.00~5.00%; TEA 0.20~0.25%; 1,2-Hexanediol 0.60~0.70%; Phenoxyethanol 0.10~0.40%; Glycerin 5.00~6.00%; Modified glutathione: 0.05–0.10%; Carnosine 0.05~0.10%; Fragrance content: 0~0.02%; LRI compatibilizer 0~0.1%; The remainder is water.

[0020] The modified glutathione, as one of the core active ingredients of the whitening composition, contains GSH encapsulated in lip coatings. This coating effectively resists trace amounts of residual metal ions in raw materials or production equipment, extending the half-life of GSH from less than one month to over six months under normal temperature and light-protected conditions. The HAase modified on the lip surface specifically binds to the CD44 hyaluronic acid receptor, which is highly expressed on the surface of melanocytes and dermal fibroblasts, precisely delivering GSH to target cells and increasing its concentration in the target area by more than 10 times. For whitening needs, GSH can directly block tyrosinase activity, inhibiting melanin production at its source. For antioxidant needs, GSH can target and eliminate reactive oxygen species around dermal fibroblasts, protecting collagen fibers from degradation. This simultaneously enhances anti-wrinkle and barrier repair effects, achieving a synergistic effect of precise whitening and deep antioxidant protection. Attached Figure Description

[0021] Figure 1 These are photos of the whitening essences No. 1 to No. 3 (from left to right) on day 0 in Example 4; Figure 2 These are photos of the whitening essences No. 1 to No. 3 (from left to right) after 15 days in Example 4; Figure 3 These are photos of the whitening essences No. 1 to No. 3 (from left to right) in Example 4 after 30 days; Figure 4 These are photos of the whitening essences No. 1 to No. 3 (from left to right) from Example 4 after 60 days. Figure 5 These are photos of the whitening essences No. 1 to No. 3 (from left to right) in Example 4 after 90 days; Figure 6 These are photos of control products 1 to 3 (from left to right) on day 0 in Example 4; Figure 7 These are photos of control products 1 to 3 (from left to right) taken 15 days ago in Example 4; Figure 8These are photos of control products 1 to 3 (from left to right) taken in Example 4 over 30 days. Figure 9 These are photos of control products 1 to 3 (from left to right) taken over 60 days in Example 4; Figure 10 These are photos of control products 1 to 3 (from left to right) taken 90 days ago in Example 4. Detailed Implementation

[0022] The following embodiments further illustrate the content of the present invention, but should not be construed as limiting the present invention. Any modifications and substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the present invention are within the scope of the present invention.

[0023] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0024] The method for preparing modified glutathione includes the following steps: (1) First, hydrogenated lecithin (HSPC), cholesterol (Chol) and dipalmitoylphosphatidylethanolamine-polyethylene glycol (DPPE-PEG) are mixed and dissolved in chloroform to form a homogeneous solution, thus obtaining a mixture; (2) The mixture was placed in a rotary evaporator and evaporated at 120 rpm and 40°C to remove the solvent and form a uniform lipid film. (3) The lipid membrane is heated in a 60°C water bath and subjected to ultrasonic treatment at a power of 250~300 W for 2 minutes to achieve hydration of the lipid membrane and obtain Lip suspension; (4) Dissolve HAase in phosphate buffer, mix it with the Lip suspension obtained in step (3), and add PEG-DA as a crosslinking agent; (5) Then, at room temperature, the pH was adjusted to 6.5~7.0 and the reaction was stirred for 45 min to complete the covalent connection; (6) Finally, the covalently linked product was dialyzed 5 times at 4°C using a 13000 Dalton dialysis bag and the PBS buffer was changed to remove unreacted crosslinking agent and unbound HAase. The liposome layer was separated by centrifugation at 150000g for 3 h, filtered through a 0.22 μm filter for sterilization, and resuspended to obtain a 100 mg / mL HAase-Lip suspension. (7) Dissolve GSH in phosphate buffer to obtain a GSH solution with a concentration of 10 mg / mL, mix it with the HAase-Lip suspension, stir at room temperature for 1 h, and then sonicate it for 15 min at 200 W using a probe sonicator. Centrifuge to remove aggregates or unloaded GSH, collect it and adjust the final concentration with PBS buffer to obtain a modified glutathione suspension with a concentration of 55 mg / mL.

[0025] Based on the above preparation method, Examples 1 to 3 and Comparative Examples 1 to 3 were prepared according to the raw material amounts provided in Table 1.

[0026] Table 1 - Raw material usage for each embodiment and comparative example

[0027] The hyaluronidase-modified liposomes prepared in each embodiment and comparative example were used to encapsulate glutathione in the preparation of whitening essence to verify its whitening, antioxidant effects, and ability to extend product shelf life.

[0028] The whitening essence is prepared by separately mixing phase A, phase B, phase C, and phase D, and then stirring and dispersing the four mixtures evenly. The proportions of each phase composition are shown in Table 2.

[0029] Table 2 - Ingredients of Whitening Essence Lotion

[0030] The specific steps include: 1) Add carbomer from phase A to a beaker, add 1,3-butanediol and disperse evenly, then add deionized water and stir evenly. Finally, add the remaining materials of phase A in sequence, and heat in a water bath to 75~85℃ while stirring. Keep warm for 30 min, and then homogenize using a homogenizer for 3~5 min. 2) Stir and cool to below 40℃, add phase B, and stir until homogeneous; 3) Dissolve carnosine and modified glutathione in water beforehand, then add 1,2-hexanediol, phenoxyethanol, glycerol and 1,3-butanediol, stir well to obtain phase C; 4) Add phase C to phase A and stir until well mixed; 5) Add the pre-mixed D phase and stir until well combined.

[0031] Example 4: Experimental Protocol for Verifying the Efficacy and Shelf Life of Whitening Essence (1) Experimental materials and instruments Experimental samples: Whitening essences No. 1 to No. 3 were prepared by encapsulating glutathione with hyaluronidase-modified liposomes obtained in Examples 1 to 3, respectively; control products No. 1 to No. 3 were prepared by encapsulating glutathione obtained in Comparative Examples 1 to 3, respectively.

[0032] Reagents: Tyrosinase, L-tyrosine, DPPH (1,1-diphenyl-2-trinitrophenylhydrazine), PBS buffer (pH=6.5~7.0), methanol, anhydrous ethanol, glutathione assay kit, human immortalized keratinocytes (HaCaT) purchased from the Cell Bank of the Chinese Academy of Sciences, complete cell culture medium, CCK-8 kit and trypsin-EDTA digestion solution (0.25%).

[0033] Instruments: Microplate reader, high-speed centrifuge, high-performance liquid chromatograph (HPLC), pH meter, constant temperature and humidity chamber, ultraviolet-visible spectrophotometer, fluorescence microscope.

[0034] (2) Cell proliferation toxicity test (2-1) HaCaT cells in the logarithmic growth phase were digested with trypsin-EDTA digestion solution, centrifuged to collect the cells, resuspended in complete culture medium, and the cell concentration was adjusted to 1×10⁻⁶. 4 cells / mL; (2-2) Add 100 μL of cell suspension to each well of a 96-well cell culture plate and incubate at 37°C and 5% CO2 for 24 h to allow the cells to adhere and grow. (2-3) Discard the old culture medium in the 96-well plate and add the corresponding solutions according to the group: add 100 μL of different concentrations of essence sample solution to each well of the experimental group; add 100 μL of PBS buffer to each well of the negative control group; add 100 μL of complete culture medium to each well of the blank control group. (2-4) Place the 96-well plate in a 37℃, 5% CO2 incubator and incubate for 24 h, 48 h and 72 h respectively; (2-5) Before each time point, add 10 μL of CCK-8 reagent to each well and gently shake the 96-well plate to mix the reagent with the culture medium thoroughly. (2-6) Continue incubation at 37℃ and 5% CO2 for 2 h; (2-7) Use an ELISA reader to measure the absorbance (A value) of each well at a wavelength of 450 nm and record the data.

[0035] (2-8) Formula for calculating relative proliferation rate: RGR (%) = (Experimental group A value - Blank control group A value) / (Negative control group A value - Blank control group A value) × 100% Test results: Within the experimentally set concentration range (0.625%~5%), after 24 h, 48 h, and 72 h of treatment with the whitening essence containing HAase-Lip-GSH, the relative cell proliferation rate (RGR) of HaCaT cells was ≥80%, and the cytotoxicity level was 1~2, with no obvious cytotoxicity. Moreover, as the concentration of the essence decreased, the relative cell proliferation rate did not decrease significantly (P>0.05), proving that the whitening essences No. 1 to No. 3 have good safety for skin cells.

[0036] (3) In vitro tyrosinase inhibition rate test Experimental principle: Tyrosinase is the core enzyme in melanin synthesis. By detecting the degree of inhibition of tyrosinase activity in the sample, the skin whitening potential can be characterized.

[0037] Experimental steps: (3-1) Prepare a tyrosinase solution with a concentration of 5 U / mL, an L-tyrosine solution with a concentration of 2 mmol / L, and sample solutions with different dilution ratios (take each essence and dilute it 10 times, 20 times, and 50 times with PBS buffer). (3-2) Set up a blank group, a sample zeroing group, and an experimental group, and perform sample loading operations in a 96-well plate: Blank group: Add 50 μL of tyrosinase solution and 50 μL of PBS buffer, and incubate at 37°C for 10 min; Sample zeroing group: Add 50 μL PBS buffer and 50 μL sample solution, and incubate at 37℃ for 10 min; Experimental group: Add 50 μL of tyrosinase solution and 50 μL of sample solution, and incubate at 37℃ for 10 min; (3-3) Add 50 μL of L-tyrosine solution to the blank group and experimental group, and add 50 μL of PBS buffer to the sample zeroing group. After incubating all three groups for another 20 min, use an ELISA reader to detect the absorbance (A) of each group at a wavelength of 475 nm. (3-4) Calculation of tyrosinase inhibition rate: To eliminate the interference of the sample's own color on the detection results, the baseline is calibrated using the absorbance of the zeroing group of the sample. The inhibition rate is calculated using the following formula: Inhibition rate (%) = (A blank - A sample) / (A blank - A sample zeroing) × 100% Test results: The whitening essence No. 1 showed a tyrosinase inhibition rate of 95.1%, Whitening Essence No. 2 showed a tyrosinase inhibition rate of 96.3%, and Whitening Essence No. 3 showed a tyrosinase inhibition rate of 94.4%. In comparison, the control product No. 1 showed a tyrosinase inhibition rate of 94.5%, the control product No. 2 showed a tyrosinase inhibition rate of 90.7%, and the control product No. 3 showed a tyrosinase inhibition rate of 93.9%. The inhibition rates of the three whitening essences were significantly higher than the control product and the blank group, proving their superior whitening efficacy. The inhibition rate of control product No. 2 was significantly lower than that of whitening essence No. 1, indicating that an improper ratio of HAase to DPPE-PEG led to a decrease in targeted whitening effect.

[0038] (4) In vitro melanocyte depigmentation experiment Experimental principle: By co-incubating with B16 melanoma cells, changes in intracellular melanin content are detected to verify the actual whitening effect.

[0039] Experimental steps: (4-1) B16 cells were seeded in 6-well plates at a density of 5 × 10⁶ cells / well. 4 Cells / well, cultured for 24 h until adherent; (4-2) Add culture medium containing each essence (final concentration of sample is 0.1%) to the blank group, and continue to culture for 48 h; (3-3) Discard the culture medium, wash the cells with PBS, add 10% DMSO solution containing 1 mol / L NaOH, and incubate in a water bath at 80 ℃ for 30 min to dissolve the melanin; (4-4) Measure the absorbance at 405 nm using an ELISA reader and calculate the relative melanin content: Relative melanin content (%) = Sample A / Blank A × 100% Test results: The relative melanin content in the experimental group was significantly lower than that in the control group, proving that it can effectively inhibit melanin production; the melanin content of control product No. 1 was higher than that of whitening essence No. 1, proving that the low HSPC ratio resulted in poor encapsulation effect, and glutathione could not effectively act on target cells.

[0040] (5) Accelerated stability test of product shelf life Experimental principle: Accelerated aging by constant temperature and humidity simulates the long-term storage state of the product, and tests the glutathione retention rate and appearance stability.

[0041] Experimental steps: (5-1) Seal each essence and place it in a constant temperature and humidity chamber at 45℃ and 75% relative humidity, and take samples at 0 d, 15 d, 30 d, 60 d and 9 d respectively; (5-2) Appearance indicators: Observe whether the sample shows phenomena such as layering, turbidity, precipitation, discoloration, etc.; (5-3) Retention rate of active ingredients: The content of glutathione at each time point was detected by HPLC, and the retention rate was calculated. Retention rate (%) = Glutathione content after storage / Initial content × 100% The test results are shown in Table 1: Table 1 - Accelerated Stability Test Records

[0042] The three whitening serums in the experimental group showed no significant changes in appearance after 90 days, with glutathione retention rate >90%; the retention rate of the three control products had dropped to <70% after 60 days, and obvious precipitation (liposome rupture) could be observed in the photos of control product No. 3 at both 60 and 90 days, proving that it had a shorter shelf life. The data in Table 1 shows that the retention rate of Whitening Essence No. 3 is higher than that of Essence No. 1, proving that trehalose can significantly extend the product's shelf life.

[0043] (6) DPPH free radical scavenging ability test Experimental steps: (6-1) Prepare a 0.1 mmol / L DPPH ethanol solution and a 10-fold diluted sample solution; (6-2) The whitening essence and control product stored for 60 days were used as samples in the above accelerated stability test; 2 mL of DPPH solution was mixed with 2 mL of sample solution, and the mixture was allowed to stand in the dark for 30 min. The absorbance (A) was measured at a wavelength of 517 nm. (6-3) For the blank group, ethanol was used instead of the sample solution, and the clearance rate was calculated: Clearance rate (%) = (A blank - A sample) / A blank × 100% Test results: The DPPH scavenging rates of Whitening Essence No. 1 were 74.4%, No. 2 were 74.1%, and No. 3 were 76.9%. In comparison, the DPPH scavenging rates of Control Product No. 1 were 55.9%, No. 2 were 44.1%, and No. 3 were 48.6%. The DPPH free radical scavenging rates of the Whitening Essence groups were significantly higher than those of the control group, demonstrating that even without added antioxidants, the Whitening Essence retains good DPPH free radical scavenging efficacy even after long-term storage. Control Product No. 2 had the lowest scavenging rate, indicating that the low HAase ratio led to insufficient targeted delivery, preventing GSH from efficiently reaching oxidative stress targets.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing modified glutathione, characterized in that, Including the following steps: 1) Obtain the liposome suspension, disperse it by ultrasonication, mix it with hyaluronidase and cross-linking agent, and stir to obtain HAase-Lip suspension; 2) Mix glutathione with the HAase-Lip suspension, stir and react, and then sonicate to obtain the product.

2. The preparation method according to claim 1, characterized in that, The raw materials for the liposome suspension include hydrogenated lecithin, cholesterol, and dipalmitoylphosphatidylethanolamine-polyethylene glycol; preferably, by weight, the hydrogenated lecithin is 5-7 parts, the cholesterol is 2-3 parts, and the dipalmitoylphosphatidylethanolamine-polyethylene glycol is 1-2 parts.

3. The preparation method according to claim 2, characterized in that, The solvent for the liposome suspension is chloroform.

4. The preparation method according to claim 1, characterized in that, Step 1) The power of ultrasonic dispersion is 250~300W, and the duration is 2~5 minutes; Step 2) The power of ultrasonic treatment is 150~200W, and the duration is 10~15 minutes.

5. The preparation method according to claim 2, characterized in that, The concentration of the hyaluronidase is 1~5 mg / mL; the mass ratio of dipalmitoylphosphatidylethanolamine-polyethylene glycol to the hyaluronidase is (10~20):

1.

6. The preparation method according to claim 1, characterized in that, The crosslinking agent is polyethylene glycol diacrylate, accounting for 0.5-1% of the HAase-Lip suspension by mass.

7. The preparation method according to claim 1, characterized in that, Step 1) When adding hyaluronidase, trehalose is also added, and the mass ratio of trehalose is 1~2% of the HAase-Lip suspension.

8. A modified glutathione, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 7.

9. A whitening composition, characterized in that, The raw materials include carbomer, trehalose, betaine, allantoin, glyceryl polyether-26, sodium EDTA-2, butylene glycol, triethanolamine, 1,2-hexanediol, phenoxyethanol, glycerol, carnosine, and glutathione, wherein the glutathione is the modified glutathione as described in claim 8.

10. The whitening composition according to claim 9, characterized in that, The raw materials also include flavorings and / or compatibilizers.

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