Water-in-oil preparation of PDRN, preparation method of water-in-oil preparation and cosmetic

Abstract

The invention relates to the technical field of cosmetics, in particular to a PDRN water-in-oil preparation, a preparation method of the PDRN water-in-oil preparation and cosmetics. The PDRN water-in-oil system which is high in stability, good in ductility and good in skin feeling experience is obtained by optimizing the variety and the concentration of the water-phase salt and adjusting the variety and the relative proportion of the oil-phase composition. The preparation is prepared from the following raw materials: water, PDRN, sodium citrate, 1, 2-hexanediol, polyol, isohexadecane, isononyl isononanoate, a vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, polydimethylsiloxane, octyl polytrimethylsiloxane, an emulsifying agent and a preservative. Experiments show that the PDRN keeps good dispersity and activity in the water-in-oil system, and has good stability. In addition, the PDRN water-in-oil preparation prepared by the invention has good ductility, and is smooth and easy to push away when being smeared.

Description

Technical Field

[0001] This invention relates to the field of cosmetic technology, and more particularly to water-in-oil formulations of PDRN, their preparation methods, and cosmetics. Background Technology

[0002] PDRN, short for polydeoxyribonucleotide, is a bioactive polynucleotide polymer composed of numerous deoxyribonucleotides linked by phosphodiester bonds. In cosmetics, it is known as sodium DNA. PDRN activates adenosine A2A receptors on cells, initiating multiple signaling pathways, increasing anti-inflammatory factors, reducing inflammatory factors, and inhibiting inflammatory responses. Simultaneously, it promotes fibroblast proliferation, secretes growth factors (such as EGF, FGF, and IGF), reshapes the internal environment of damaged skin, and promotes VEGF-mediated capillary formation, providing the skin with the nutrients needed for repair and removing aging products. PDRN is a rapidly emerging functional ingredient that has seen significant activity in the past two years, with proven effects including moisturizing, repairing, soothing, anti-wrinkle, firming, whitening, and brightening.

[0003] However, the practical application of PDRN has long been limited by its inherent physicochemical instability and delivery efficiency bottlenecks. On the one hand, PDRN itself is unstable; its phosphodiester bonds are prone to hydrolysis and breakage, and its nucleotide bases are highly sensitive to oxidation, light, temperature fluctuations, and pH changes. Furthermore, the negative charge carried by its molecules easily attracts metal ions for catalytic oxidation and degradation. On the other hand, as a large-molecule bioactive substance, PDRN is difficult to penetrate the lipid barrier of the stratum corneum and is easily degraded rapidly by nucleases in vivo, significantly reducing its effectiveness in transdermal delivery. To address these issues, the industry has adopted W / O type emulsions to encapsulate, protect, and deliver PDRN. Among these, the water-in-oil system, due to its "oil-encapsulated water" structure, exhibits outstanding water-locking and moisturizing properties and occlusive properties. Its oil phase is a continuous phase, forming a physical barrier to isolate environmental factors, reduce PDRN degradation, and prolong its active time. It also improves compatibility with the stratum corneum, enhancing transdermal efficiency. Moreover, it allows for flexible formulation adjustments to suit different product needs, broadening the range of PDRN dosage forms.

[0004] Although water-in-oil systems provide a feasible path for the stabilization and efficient delivery of PDRN, the application of PDRN in water-in-oil systems can lead to problems such as poor compatibility and viscosity reduction. This is mainly because: PDRN has a large molecular weight and certain charge properties, making it easy to combine with salts, thus forming flocculation and precipitation. At the same time, the large molecular characteristics of PDRN increase the viscosity of the aqueous phase, disrupting the system's kinetic equilibrium and causing viscosity reduction. Furthermore, the continuous phase of a water-in-oil system is the oil phase, which naturally results in a thick feel. In addition, residual proteins, polysaccharides, and other impurities in the PDRN raw material, or trace cationic substances in the system, can act as demulsifiers, neutralizing the surface charge of water droplets, replacing interfacial emulsifiers, disrupting the stable structure of the electric double layer, and accelerating oil-water separation, demulsification, and stratification.

[0005] Therefore, developing a highly stable water-in-oil system with stable interfacial membranes, strong anti-demulsification ability, and the ability to maintain PDRN bioactivity during long-term storage has become a key technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a stable, skin-friendly PDRN water-in-oil system and its preparation method.

[0007] The raw materials for preparing the PDRN water-in-oil formulation provided by this invention include an aqueous phase raw material and an oil phase raw material. The aqueous phase raw material includes a polyol, 1,2-hexanediol, sodium citrate, PDRN, and water. The oil phase raw material is composed of silicone oil, alkanes, and synthetic oils.

[0008] In this invention, the silicone oil is selected from at least one of polydimethylsiloxane with a viscosity of 1.5, cyclopentadimethylsiloxane, methyl polytrimethylsiloxane, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer, and octyl polytrimethylsiloxane.

[0009] The alkane is selected from at least one of isohexadecane and C15-19 alkane.

[0010] The synthetic oil is selected from at least one of isononyl isononanoate, coconut oil-caprylate / decanoate, macadamia oleate, butanediol dicaprylate / decanoate, and pentaerythritol tetraethylhexanoate.

[0011] In this invention, the raw materials for preparing the PDRN water-in-oil formulation include water, PDRN, sodium citrate, 1,2-hexanediol, polyol, isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane crosslinked polymer, polydimethylsiloxane, octyl polytrimethylsiloxane, emulsifier, and preservative.

[0012] This invention mainly targets the screening of components in raw materials that affect stability, extensibility, and skin feel, and optimizes the content of these components.

[0013] Compared to other salts (inorganic salts or salts of other organic acids), the water-in-oil system obtained using citrate exhibits high viscosity stability. Based on this, the concentration of citrate was further optimized. The results showed that 0.2% sodium citrate readily forms a pale blue gel with PDRN, increasing the risk of PDRN use and process stability issues. However, at a sodium citrate concentration of 0.1%, the water-in-oil system not only maintained good viscosity stability but also demonstrated superior skin feel and properties.

[0014] Compared to other oil phase compositions, the combination of isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane cross-linked polymer, polydimethylsiloxane, and octyl polytrimethylsiloxane has a greater advantage in stability, can effectively regulate the fluidity and spreadability of the oil phase, reduce the heaviness of the oil film, and improve the refreshing and smoothness of the formulation during use.

[0015] In some embodiments, the preparation raw materials include the following mass fractions: 0.1%~0.5% PDRN, 0.1%~0.2% sodium citrate, 0.5% 1,2-hexanediol, 9% polyol, 2.5%~5% isohexadecane, 2%~5% isononyl isononanoate, 0.3%~1% vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane crosslinked polymer, 3.5%~7% polydimethylsiloxane, 1.5% octyl polytrimethylsiloxane, 1.9%~2.6% emulsifier, and 0.5% preservative, with the balance being water.

[0016] In some embodiments, the preservative is p-hydroxyacetophenone.

[0017] In one specific embodiment, the mass fraction of each component in the water-in-oil formulation is as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 2.5%, isononyl isononanoate 5%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer 0.4%, polydimethylsiloxane 5.6%, octyl polytrimethylsiloxane 1.5%, emulsifier 1.9%, and the balance being water;

[0018] In another specific embodiment, the mass fraction of each component in the water-in-oil formulation is as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 2.5%, isononyl isononanoate 4.8%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer 0.6%, polydimethylsiloxane 5.6%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.2%, and the balance being water;

[0019] In another specific embodiment, the mass fraction of each component in the water-in-oil formulation is as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 3%, isononyl isononanoate 4%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer 0.8%, polydimethylsiloxane 5.7%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.6%, and the balance being water;

[0020] In another specific embodiment, the mass fraction of each component in the water-in-oil formulation is as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.2%, PDRN 0.1%, isohexadecane 5%, isononyl isononanoate 4%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer 1%, polydimethylsiloxane 3.5%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.6%, and the balance being water;

[0021] In another specific embodiment, the mass fraction of each component in the water-in-oil formulation is as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 4%, isononyl isononanoate 2%, vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane crosspolymer 0.3%, polydimethylsiloxane 7%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.6%, and the balance being water.

[0022] In this invention, the polyol is glycerol and butanediol, the emulsifier is cetyl PEG / PPG-10 / 1 polydimethylsiloxane, and the preservative is p-hydroxyacetophenone. In the polyol, the butanediol is 1,3-butanediol, and the mass ratio of glycerol to butanediol is 4:5.

[0023] Furthermore, the present invention also provides a method for preparing the PDRN water-in-oil formulation as described above, comprising:

[0024] Water, PDRN, 1,2-hexanediol, polyol, and preservative were mixed and then sodium citrate was added to obtain the aqueous phase.

[0025] Isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer, polydimethylsiloxane, octyl polytrimethylsiloxane and emulsifier are mixed to obtain an oil phase;

[0026] The aqueous phase is added to the oil phase, and the mixture is homogenized to obtain the water-in-oil preparation.

[0027] In this invention, to better mix the components in the oil phase, the oil phase is homogenized before being mixed with the aqueous phase. The homogenization conditions for the oil phase include homogenization at 1000-10000 rpm for 1-10 minutes. In a specific embodiment, the homogenization conditions include homogenization at 3000-70000 rpm for 3-7 minutes. More specifically, the homogenization conditions include homogenization at 4000-60000 rpm for 4-6 minutes. Further still, the homogenization conditions include homogenization at 4500-5500 rpm for 4.5-5.5 minutes. As a feasible example, the oil phase is homogenized at 5000 rpm for 5 minutes before being mixed with the aqueous phase.

[0028] In this invention, a water-in-oil formulation is prepared using a homogenization method. The homogenization conditions include homogenization at 1000-10000 rpm for 5-20 min; in specific embodiments, the homogenization conditions include homogenization at 3000-7000 rpm for 7-15 min; more specifically, the homogenization conditions include homogenization at 4000-6000 rpm for 8-13 min; even further, the homogenization conditions include homogenization at 4500-5500 rpm for 9-11 min; as a feasible example, the homogenization is homogenization at 5000 rpm for 10 min.

[0029] The preparation method provided by this invention has a simple process flow, but it can prepare water-in-oil formulations with excellent stability, spreadability and skin feel.

[0030] The present invention also provides the application of the water-in-oil formulation as described above or the water-in-oil formulation prepared by the method described above in the preparation of cosmetics.

[0031] The cosmetic described in this invention has effects such as moisturizing, repairing, soothing, anti-wrinkle, and whitening.

[0032] Furthermore, the present invention also provides a cosmetic product comprising a water-in-oil formulation as described above or a water-in-oil formulation prepared by the method described above.

[0033] The oil-in-water formulation provided by this invention can be applied to any cosmetic dosage form. As a feasible example, the dosage form of the cosmetic is at least one of the following: facial cleanser, makeup remover, cleansing cream, cleansing lotion, facial mask, bath gel, skin cream, lotion, toner, shampoo, hair treatment, shaving cream, conditioner, hair cream, hair treatment, and lip balm.

[0034] The cosmetics of this invention may include, in addition to the water-in-oil formulations described above, other active ingredients with skin-care effects that can be used in cosmetics, such as ceramides, hyaluronic acid, vitamin E, asiaticoside, niacinamide, etc. Furthermore, the cosmetics of this invention may also include acceptable excipients, including but not limited to moisturizers, emollients, oils, waxes, emulsifiers, thickeners, stabilizers, pH adjusters, antioxidants, preservatives, fragrances, pigments, chelating agents, water-soluble or oil-soluble active ingredients, film-forming agents, solubilizers, penetration enhancers, buffers, cooling agents, oil-absorbing powders, and film-forming polymers.

[0035] Furthermore, the present invention also provides a skin care method comprising applying, on the skin surface, an oil-in-water preparation as described above or a cosmetic as described above.

[0036] In this invention, the application methods of the cosmetic include, but are not limited to, smearing, spraying, wiping, dotting, patting, applying wet compresses, spraying, coating, applying, massaging, or using tools for assistance.

[0037] This invention optimizes the type and concentration of the aqueous salt and adjusts the type and relative proportion of the oil phase composition to obtain a PDRN water-in-oil system with high stability, good spreadability, and excellent skin feel. The raw materials for this formulation include water, PDRN, sodium citrate, 1,2-hexanediol, polyol, isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane crosslinking polymer, polydimethylsiloxane, octyl polytrimethylsiloxane, emulsifier, and preservative. Experiments show that using sodium citrate and a specific oil phase combination enables PDRN to maintain good dispersibility and activity in the water-in-oil system. Furthermore, this water-in-oil system maintains a uniform emulsion form under high temperature, low temperature, or cyclic conditions, without stratification, demulsification, or precipitation. In addition, the PDRN water-in-oil formulation prepared by this invention has good spreadability, is smooth and easy to spread when applied, avoids the greasy feeling common in traditional water-in-oil formulations, and improves the skin feel during use. Attached Figure Description

[0038] Figure 1 The droplet morphology of the product in Example 1 is shown in the left image (40x magnification) and the right image (20x magnification).

[0039] Figure 2 The droplet morphology of the product in Example 2 is shown in the left image (40x magnification) and the right image (20x magnification).

[0040] Figure 3 The droplet morphology of the product in Example 3 is shown in the left image (40x magnification) and the right image (20x magnification).

[0041] Figure 4The droplet morphology of the product in Example 4 is shown in the left image (40x magnification) and the right image (20x magnification).

[0042] Figure 5 The droplet morphology of the product in Example 5 is shown in the left image (40x magnification) and the right image (20x magnification).

[0043] Figure 6 The droplet morphology of the product in Comparative Example 1 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0044] Figure 7 The droplet morphology of the product in Comparative Example 2 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0045] Figure 8 The droplet morphology of the product in Comparative Example 3 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0046] Figure 9 The droplet morphology of the product in Comparative Example 4 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0047] Figure 10 The droplet morphology of the product in Comparative Example 5 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0048] Figure 11 The droplet morphology of the product in Comparative Example 6 is shown. The left image is magnified 40 times, and the right image is magnified 20 times.

[0049] Figure 12 A bar chart showing the skin feel evaluation results for each group of samples;

[0050] Figure 13 A radar chart showing the skin feel evaluation results for each group of samples. Detailed Implementation

[0051] This invention provides water-in-oil formulations of PDRN, methods for their preparation, and cosmetic applications. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired results. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art will clearly be able to modify or appropriately alter and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0052] Unless otherwise defined in this invention, the scientific and technical terms associated with this invention shall have the meanings understood by one of ordinary skill in the art.

[0053] The terms “comprising,” “including,” and “having” are used interchangeably to indicate the inclusiveness of a scheme, meaning that the scheme may contain elements other than those listed. It should also be understood that the use of “comprising,” “including,” and “having” herein also provides for schemes “consisting of…”.

[0054] The term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone. A and B can be singular or plural.

[0055] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0056] The numerical ranges and parameters involved in this invention have been presented as precisely as possible in the specific embodiments. However, any numerical value inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all numerical ranges or specific data used in this disclosure may have a reasonable deviation within a certain range, such as ±10%, ±5%, ±1%, or ±0.5%.

[0057] The embodiments and comparative examples of this invention describe some examples. These embodiments illustrate certain implementations of the invention. However, this does not mean that the effects of the invention can only be achieved in these examples. In fact, good results can be achieved at any concentration of the components between the two endpoint values ​​shown in the embodiments.

[0058] The test materials used in this invention are all common commercial products and can be purchased on the market.

[0059] The instruments and equipment include:

[0060] The homogenizer model is IKAT25 and it comes from IKA (IKA Factory and its subsidiaries).

[0061] The centrifuge, model L600, is from Hunan Xiangyi Laboratory Instrument Development Co., Ltd.

[0062] The electronic balance, model ML4002T, is from Mettler Tolly Instruments (Shanghai) Co., Ltd.

[0063] The analytical balance, model ML204T, is from Mettler Tolly Instruments (Shanghai) Co., Ltd.

[0064] The digital viscometer, model NDJ-8S, is from Shanghai Jinghai Instrument Co., Ltd.

[0065] The low-temperature freezer, model HYC-390, is from Qingdao Haier Biomedical Co., Ltd.

[0066] The constant temperature forced-air drying oven, model GZX-9240MBE, was manufactured by the Medical Equipment Factory of Shanghai Boxun Business Co., Ltd.

[0067] The electric thermostatic water bath (four-hole) model HHS is manufactured by the Medical Equipment Factory of Shanghai Boxun Business Co., Ltd.

[0068] The benchtop pH meter, model S220-Bio, is from Mettler Toledo International Ltd.

[0069] The electric mixer, model RW20, is from IKA (IKA Factory Partnership).

[0070] The biological microscope, model BX43, is from Olympus Corporation.

[0071] The raw materials involved include:

[0072] p-Hydroxyacetophenone was purchased from Aoxue Chemical; hexanediol was purchased from Aoxue Chemical; sodium citrate was purchased from Shanghai Huilang Chemical; sodium chloride was purchased from Shanghai Guzidi Industrial Co., Ltd.; sodium DNA was purchased from Shanghai Yunchu Biotechnology Co., Ltd.; isohexadecane was purchased from Shanghai Zhenheng International Trade Co., Ltd.; isononyl isononanoate was purchased from Guangzhou Baihaobo; vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer model KSP 100 and polydimethylsiloxane (trade name KF-96l-1.5cs) were purchased from Maichi Chemical; octyl polytrimethylsiloxane (trade name Silsoft) was purchased from Maichi Chemical. TM 034 fluid was purchased from Shanghai Puen; butanediol dioctanoic acid / didecanoic acid ester was purchased from Shanghai Faenkai Industrial Co., Ltd.; C15-19 alkyl was purchased from Guangzhou Baihaobo Co., Ltd.; cyclopentapolydimethylsiloxane was purchased from Guangzhou Juyang Chemical Technology Co., Ltd.; methyl polytrimethylsiloxane was purchased from Guangzhou Juyang Chemical Technology Co., Ltd.; pentaerythritol tetra(ethylhexanoic acid) ester was purchased from Guangzhou Bisheng Trading Co., Ltd.

[0073] It should be understood that in the various embodiments of this application, the sequence numbers of the above processes do not imply the order of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The present invention is further illustrated below with reference to embodiments:

[0074] Examples 1-5

[0075] The formulations for each embodiment are shown in Table 1.

[0076] Table 1. Composition of each embodiment (in mass percentage)

[0077]

[0078] The preparation process includes:

[0079] According to the above mass percentages, the solvent water, sodium DNA, polyol, and preservative are mixed evenly, and then sodium citrate is added to obtain phase A.

[0080] Add the oil phase and emulsifier to the main beaker to obtain phase B, and homogenize at 5000 rpm for 5 min.

[0081] Phase A is slowly added to Phase B, and homogenization is carried out at 5000 rpm for 10 minutes to obtain a material with a uniform and delicate appearance.

[0082] Comparative Examples 1-11

[0083] The formulations for each comparative example are shown in Table 2.

[0084] Table 2. Composition of each comparative example (in mass percentage)

[0085]

[0086] Alternatively, the proportions of each formula are shown in Table 3.

[0087] Table 3. Composition of each comparative proportion (in mass percentage)

[0088]

[0089] The preparation process of Comparative Example 1 includes:

[0090] According to the above mass percentages, the solvent water, sodium DNA, polyol, and preservative are mixed evenly, and then sodium chloride is added to obtain phase A.

[0091] Add the oil phase and emulsifier to the main beaker to obtain phase B, and homogenize at 5000 rpm for 5 min.

[0092] Phase A is slowly added to Phase B, and homogenization is carried out at 5000 rpm for 10 minutes to obtain a material with a uniform and delicate appearance.

[0093] The preparation processes of Comparative Examples 2 to 11 are the same as those of Examples 1 to 5.

[0094] Example 1: Viscosity behavior of the system

[0095] The viscosity of the samples prepared in Examples 1 to 5 and Comparative Examples 1 to 11 was measured using a Brookfield viscometer with the rotor speed set to 6# and 6 rpm.

[0096] During testing, it is important to complete the testing as soon as possible after the material is discharged.

[0097] Day 2 refers to the results of testing after each group of samples has been placed at room temperature for 24 hours.

[0098] One week refers to the results of testing after each group of samples has been placed at room temperature (℃) for 7 days.

[0099] "January" refers to the results of testing after each group of samples has been placed at room temperature (℃) for one month.

[0100] The results are shown below:

[0101] Table 4 Viscosity test results for each system

[0102]

[0103] Water-in-oil emulsions have certain viscosity requirements: if the viscosity is too low, the formulation is prone to separation, oil separation, and water exudation, resulting in poor stability; if the viscosity is too high, the formulation becomes too thick, making the process difficult, and also causing problems such as difficulty in application, a heavy feel on the skin, and pilling. Therefore, the prepared water-in-oil emulsion should have suitable viscosity and flowability.

[0104] As can be seen from the viscosity test results above, except for Comparative Example 6 and Comparative Example 11, which have flowability upon discharge, the other samples have suitable discharge viscosity and do not have flowability.

[0105] The high viscosity stability of Examples 1 to 5 indicates that the examples designed in this experiment are effective.

[0106] Comparative Example 1 showed better viscosity stability, while Comparative Example 2 experienced a more significant viscosity reduction. Comparing their formulations, the only difference lies in the type of salt used: Comparative Example 1 used 0.2% sodium chloride, while Comparative Example 2 used 0.2% sodium citrate. This experiment demonstrates that sodium citrate is more effective in stabilizing PDRN-containing water-in-oil systems. Furthermore, aqueous solution experiments showed that 0.2% sodium citrate readily forms a pale blue gel with PDRN, increasing the risk to PDRN utilization and process stability. Therefore, 0.1% sodium citrate was used in all other experiments.

[0107] Comparative Examples 4 to 6 showed stable viscosity retention, but the overall viscosity was low, requiring further verification of the system's long-term stability.

[0108] Comparing Comparative Example 7 and Example 1, replacing some of the isononyl isononanoate with ethyl macadamia oleate resulted in reduced compatibility of the oil phase, poor viscosity retention, a higher risk of instability, and a greater sense of skin stickiness in the later stages.

[0109] Comparative Example 8, which only contains alkane and silicone oil, has a low initial viscosity and poor retention rate, resulting in a higher risk of instability.

[0110] Comparative Example 9 used D5, which has an extremely light feel, and ethyl macadamia oleate, which has a moderate feel. However, the latter has a high degree of resistance to skin texture and a higher risk of instability.

[0111] Comparative Example 10 uses methyl polytrimethoxysilane and coconut oil alcohol-caprylate / caprylate with a refreshing feel. After application and absorption, it leaves an oily residue, feels rough on the skin, and has a low viscosity retention rate, indicating a high risk of instability.

[0112] Comparative Example 11 used only synthetic oil and 1,5-viscosity polydimethylsiloxane. The material had strong fluidity when discharged and demulsified overnight at -18°C.

[0113] Experimental Example 2: Long-term stability performance of the system

[0114] The comparative and example samples with acceptable viscosity were placed under normal conditions (commonly used conditions for cosmetic stability testing: RT (room temperature), 4℃, 40℃, -18℃, 50℃, cycling, where the cycling test condition is -18℃ / 24h + 45℃ / 24h as one cycle) to examine their stability.

[0115] The verification results are as follows:

[0116] Table 5. Long-term stability test results of each system

[0117]

[0118] As can be seen from the stability test results above, the compositions prepared in this invention have good stability after 4 weeks of stability testing in Examples 1, 2, 3, 4, and 5, indicating that a stable PDRN water-in-oil system can be prepared using 0.1% sodium citrate and a suitable oil composition.

[0119] Comparing Comparative Example 1 and Comparative Example 2, it can be found that, compared with sodium chloride, sodium citrate can not only maintain the stability of the system viscosity, but also ensure the long-term stability of the system.

[0120] Comparative Examples 4, 5, and 6 showed stratification after one week under high temperature of 40°C or 50°C, freezing at -18°C, and cyclic conditions, indicating that the oil composition has a significant impact on the stability of the system.

[0121] Comparative Example 3 showed stratification after one week at 50°C. Comparing Comparative Example 3 and Example 1, the only difference was the 0.5% PDRN content, indicating that PDRN significantly improves the stability of the water-in-oil system with high water content at high temperatures. It is speculated that this is because PDRN increases the viscosity of the aqueous phase, thus preventing water efflux at high temperatures.

[0122] Comparing Comparative Examples 4 and 5, it can be found that maintaining a constant oil phase ratio, using any two of the following: silicone oils (polydimethylsiloxane, vinyl polydimethylsiloxane / polymethylsilsesquioxane crosslinked polymer, octyl polytrimethylsiloxane), alkane (isohexadecane), and synthetic fats (isononyl isononanoate), cannot guarantee the stability of the system.

[0123] Experimental Example 3: Microscopic Characterization

[0124] 3.1 Test Principle

[0125] It utilizes visible light refraction and imaging to magnify and observe tiny objects that are invisible to the naked eye, relying on a two-stage magnification system consisting of an objective lens and an eyepiece.

[0126] First, the light source illuminates the sample (transmitted light for transparent samples, reflected light for opaque samples). The light carries the structural details of the sample after passing through / reflecting. Second, the objective lens (the lens closest to the sample) first magnifies the sample to form a magnified real image. Finally, the eyepiece (the lens closest to the eye) magnifies the real image formed by the objective lens a second time, ultimately forming a virtual image that can be seen by the naked eye.

[0127] 3.2 Test Methods

[0128] Turn on the instrument: turn on the power and the computer.

[0129] Preparation: Place the material on a glass slide, press it down with a coverslip. When placing the sheet on the stage, the coverslip must face upwards, and the sheet must be held in place with spring clips.

[0130] Focus: Adjust the objective lens distance and observe in real time. Observe the image at an objective lens magnification of 20.

[0131] End of observation: Turn the coarse handwheel to lift the objective lens, leaving one eyepiece in the microscope tube, turn off the power, and cover the instrument with the instrument cover.

[0132] 3.3 Test Results

[0133] The samples from Comparative Examples 1-6 and Examples 1-5 of this invention were placed under an optical microscope to observe the droplet morphology and distribution. The results are as follows: Figures 1-11 .

[0134] Overall, the comparative sample showed a large and dense distribution of water droplets in the internal phase, while the example sample showed a small and uniform internal phase liquid. This further verifies from a microscopic morphology perspective that the comparative sample had poor stability, while the example sample had good stability.

[0135] Comparative Examples 1, 2, 4, 5, and 6 all exhibited a large number of unevenly distributed large droplets under an optical microscope. Comparative Example 1, in particular, showed a field of view filled with large droplets that appeared to be slowly merging. Uneven liquid distribution negatively impacts the smoothness of the paste; the higher probability of large liquid droplets merging also increases the risk of layering.

[0136] Comparing the electron micrographs of Comparative Example 3 and Example 1, it can be found that the droplets in Example 1 are dense, fine and small, while the droplets in Comparative Example 3 are large and not dense. This indicates that the addition of PDRN improves both the fineness and stability of the water-in-oil system.

[0137] Experimental Example 4: Skin Feel Characterization

[0138] 4.1 Test Principle

[0139] This study involved Asian adult skin subjects who continuously used samples under normal conditions (comparative and exemplary samples through long-term stability testing). Approximately 30 subjects self-assessed and rated the product's feel on the skin. Evaluation dimensions included: texture preference, feeling of heaviness, stickiness, melting sensation, gentleness, moisturizing sensation, smoothness, suppleness, and overall preference. Scores ranged from 1 to 9, with higher scores indicating greater satisfaction with that dimension.

[0140] 4.2 Test Methods

[0141] After cleansing, apply an appropriate amount of mask evenly to the face. Apply a thin layer and wait 15-20 minutes, or apply a thick layer and wait 30 minutes. Once the mask turns from milky white to transparent, massage in circular motions until fully absorbed by the skin. No need to wash it off.

[0142] 4.3 Test Results

[0143] Approximately 30 participants underwent a skin feel assessment test, and the average value was calculated. The results are as follows:

[0144] Table 6 Results of Subjects' Skin Sensation Assessment

[0145]

[0146] As shown in Table 6 and Figures 12-13 Examples 1 to 5 outperformed Comparative Examples 2, 3, 7 and 8 in all aspects of skin feel and overall preference, with Example 1 showing the best performance.

[0147] The examples used silicone oils (polydimethylsiloxane, vinyl polydimethylsiloxane / polymethylsilsesquioxane crosslinked polymer, octyl polytrimethylsiloxane), alkanes (isohexadecane), and synthetic oils (isononyl isononanoate), with the content of each component optimized to achieve the best skin feel. The comparative examples used a combination of two of the three types of oils, which resulted in poor performance in both stability and skin feel. This demonstrates that in the PDRN water-in-oil system studied in this invention, only a combination of all three types of oils can achieve the best skin feel and stability.

[0148] Comparing the skin feel evaluation results of Example 1 and Comparative Example 3, it can be concluded that PDRN has a significant effect on improving the feeling of stuffiness, stickiness, melting sensation and overall preference in the oil-in-water system.

[0149] Comparing Comparative Example 7 and Example 1, replacing some of the isononyl isononanoate with ethyl macadamia oleate resulted in a heavier feeling of stuffiness, stickiness, and resistance on the skin in the later stages.

[0150] Comparative Example 8 uses a blend of 1,5-viscosity polydimethylsiloxane and cyclopentapolydimethylsiloxane, which significantly reduces the smoothness and softness.

[0151] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water-in-oil formulation of PDRN, characterized in that, The raw materials for its preparation include water, PDRN, sodium citrate, 1,2-hexanediol, polyol, isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane cross-linked polymer, polydimethylsiloxane, octyl polytrimethylsiloxane, emulsifier and preservative.

2. The water-in-oil formulation according to claim 1, characterized in that, It comprises the following raw materials by mass fraction: 0.1%~0.5% PDRN, 0.1%~0.2% sodium citrate, 0.5% 1,2-hexanediol, 9% polyol, 2.5%~5% isohexadecane, 2%~5% isononyl isononanoate, 0.3%~1% vinyl polydimethylsiloxane / polymethylsiloxane sesquisiloxane crosslinked polymer, 3.5%~7% polydimethylsiloxane, 1.5% octyl polytrimethylsiloxane, 1.9%~2.6% emulsifier, and 0.5% preservative, with the balance being water.

3. The water-in-oil formulation according to claim 1 or 2, characterized in that, The preservative is p-hydroxyacetophenone; The mass fractions of each component in the water-in-oil formulation are as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 2.5%, isononyl isononanoate 5%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosspolymer 0.4%, polydimethylsiloxane 5.6%, octyl polytrimethylsiloxane 1.5%, emulsifier 1.9%, and the balance being water; Alternatively, the mass fractions of each component may be as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 2.5%, isononyl isononanoate 4.8%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosspolymer 0.6%, polydimethylsiloxane 5.6%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.2%, and the balance being water; Alternatively, the mass fractions of each component are as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.1%, PDRN 0.5%, isohexadecane 3%, isononyl isononanoate 4%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosspolymer 0.8%, polydimethylsiloxane 5.7%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.6%, and the balance being water; Alternatively, the mass fractions of each component are as follows: polyol 9%, p-hydroxyacetophenone 0.5%, 1,2-hexanediol 0.5%, sodium citrate 0.2%, PDRN 0.1%, isohexadecane 5%, isononyl isononanoate 4%, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosspolymer 1%, polydimethylsiloxane 3.5%, octyl polytrimethylsiloxane 1.5%, emulsifier 2.6%, and the balance being water; Alternatively, the mass fractions of each component may be as follows: 9% polyol, 0.5% p-hydroxyacetophenone, 0.5% 1,2-hexanediol, 0.1% sodium citrate, 0.5% PDRN, 4% isohexadecane, 2% isononyl isononanoate, 0.3% vinyl polydimethylsiloxane / polymethylsiloxane-sesquisiloxane crosspolymer, 7% polydimethylsiloxane, 1.5% octyl polytrimethylsiloxane, 2.6% emulsifier, and the balance being water.

4. The water-in-oil formulation according to claim 3, characterized in that, The polyol is glycerol and butanediol, the emulsifier is cetyl PEG / PPG-10 / 1 polydimethylsiloxane, and the preservative is p-hydroxyacetophenone.

5. The method for preparing the water-in-oil formulation according to any one of claims 1 to 4, characterized in that, include: Water, PDRN, 1,2-hexanediol, polyol, and preservative were mixed and then sodium citrate was added to obtain the aqueous phase. Isohexadecane, isononyl isononanoate, vinyl polydimethylsiloxane / polymethylsiloxane silsesquioxane crosslinked polymer, polydimethylsiloxane, octyl polytrimethylsiloxane and emulsifier are mixed to obtain an oil phase; The aqueous phase is added to the oil phase, and the mixture is homogenized to obtain the water-in-oil preparation.

6. The preparation method according to claim 5, characterized in that, The oil phase is homogenized at 5000 rpm for 5 minutes and then mixed with the aqueous phase.

7. The preparation method according to claim 5, characterized in that, The homogenization was performed at 5000 rpm for 10 minutes.

8. The use of the water-in-oil formulation according to any one of claims 1 to 4 in the preparation of cosmetics.

9. A cosmetic product, characterized in that, Includes the water-in-oil formulation according to any one of claims 1 to 4.

10. The cosmetic product according to claim 9, characterized in that, The cosmetic product is formulated as at least one of the following: facial cleanser, makeup remover, cleansing cream, cleansing lotion, facial mask, bath gel, skin cream, lotion, toner, shampoo, hair treatment, shaving cream, conditioner, hair cream, hair treatment, and lip balm.

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