Liposome with retinol wrapped by bionic ceramide as well as preparation method and application of liposome

Abstract

The invention relates to the field of lipidosome technology and skin external preparations, in particular to bionic ceramide coated retinol lipidosome and a preparation method and application of the bionic ceramide coated retinol lipidosome. The liposome is prepared from the following raw materials in parts by weight: 1.0 to 3.0 weight percent of ceramide NP, 1.0 to 3.0 weight percent of ceramide AP, 0.05 to 0.5 weight percent of ceramide EOP, 1.0 to 3.0 weight percent of cholesterol, 0.50 to 2.0 weight percent of meadowfoam seed oil, 3.0 to 10.0 weight percent of hydrogenated lecithin, 1.0 to 3.0 weight percent of retinol, 0.50 to 2.50 weight percent of tocopheryl acetate, 15.0 to 45.0 weight percent of caprylic / capric triglyceride MCT, 1.0 to 5.0 weight percent of propylene glycol, 15.0 to 45.0 weight percent of glycerol and the balance of water, the bionic layered film is constructed by the multi-subtype ceramide, cholesterol and hydrogenated lecithin, the oil phase and an antioxidant system are cooperated, the stability of retinol under light, heat and oxygen is remarkably improved, slow release is achieved, meanwhile, skin tolerance is improved, and the bionic layered film can be widely applied to essence, emulsion, face cream, ampoule and other external skin care preparations.

Description

Technical Field

[0001] This invention relates to the field of liposome technology and topical skin preparations, and particularly to a biomimetic ceramide-encapsulated retinol liposome, its preparation method and application, for improving the stability, skin compatibility and anti-aging effects of retinol. Background Technology

[0002] In the field of topical skin preparations and anti-aging cosmetics, retinol, as a classic vitamin A derivative, is widely used due to its ability to effectively promote collagen synthesis, improve skin texture, and reduce signs of photoaging. However, retinol itself exhibits significant chemical instability, easily degrading under the influence of light, heat, and oxygen, leading to reduced activity or even inactivation. Furthermore, retinol is highly irritating to the skin, commonly causing adverse reactions such as burning sensation, erythema, and peeling after use, limiting its application in high-concentration formulations and its suitability for sensitive skin.

[0003] To improve the stability and skin tolerance of retinol, liposome encapsulation strategies are commonly used in traditional technologies. Conventional phospholipid retinol liposomes, by forming a phospholipid bilayer structure, can improve the encapsulation efficiency and transdermal performance of retinol to some extent. However, their structure still faces the risk of degradation under long-term storage or changes in the external environment, and their effect on alleviating skin irritation is limited. In recent years, although novel carriers such as solid lipid nanoparticles and polymer microcapsules have been developed for retinol encapsulation, these systems have made some progress in improving loading efficiency or delaying release, but problems such as complex processes, difficulty in large-scale production, or insufficient skin affinity still exist. Especially under high loading conditions, the early burst release of retinol can still lead to significant local irritation, affecting the user experience and product safety.

[0004] On the other hand, the lipid composition of the stratum corneum is mainly composed of ceramides, supplemented by cholesterol and free fatty acids. Various ceramide subtypes, such as NP, AP, and EOP, play a crucial role in maintaining the lipid bilayer structure and barrier function of the stratum corneum. In recent years, biomimetic liposome technology, by mimicking the lipid composition and structure of human skin, has demonstrated good biocompatibility and barrier integration capabilities, providing new ideas for improving the stability of active ingredients, skin permeability, and reducing irritation. Although some studies have attempted to introduce ceramides into carrier systems, these have mostly been limited to single ceramide types or simple complex phospholipid systems, failing to fully replicate the diverse subtypes and proportions of stratum corneum lipids. Therefore, there is still room for improvement in achieving efficient biomimetic delivery and synergistic skin repair effects.

[0005] In summary, existing retinol carrier technologies have not yet effectively solved the balance problem between stability, skin tolerance, and sustained release of efficacy. There is an urgent need to develop a retinol delivery system that can realistically simulate the skin's lipid structure, has good storage stability, and is industrially feasible, so as to achieve safer and more efficient application in anti-aging skincare products. Summary of the Invention

[0006] In view of the shortcomings of the above-mentioned technologies, the present invention provides a biomimetic ceramide-encapsulated retinol liposome, which can achieve high retinol loading, high stability, sustained release and low irritation, and can be directly applied to skin care products in the form of liquid dispersion.

[0007] To achieve the above objectives, the specific technical solution of the present invention is as follows: This invention provides a biomimetic liposome encapsulating retinol with ceramide, comprising the following raw materials in parts by weight: ceramide NP 1.0–3.0 wt%, ceramide AP 1.0–3.0 wt%, ceramide EOP 0.05–0.5 wt%, cholesterol 1.0–3.0 wt%, meadowfoam seed oil 0.50–2.0 wt%, hydrogenated lecithin 3.0–10.0 wt%, retinol 1.0–3.0 wt%, tocopheryl acetate 0.50–2.50 wt%, caprylic / capric triglyceride (MCT) 15.0–45.0 wt%, propylene glycol 1.0–5.0 wt%, glycerol 15.0–45.0 wt%, and the balance being water.

[0008] Furthermore, the retinol content is 1.0–3.0 wt%, preferably 2.0 wt%.

[0009] Furthermore, the average particle size D50 is 50–300 nm, preferably 80–200 nm.

[0010] Furthermore, cholesterol and hydrogenated lecithin are present in a specific mass ratio of 4-6:2–4:4–6.

[0011] Furthermore, propylene glycol is used in conjunction with glycerol for solvation activity, osmotic pressure regulation, and improved storage stability.

[0012] Furthermore, this invention also provides a biomimetic ceramide-encapsulated retinol liposome, the specific preparation method of which includes the following steps: S1: Ceramides NP, AP, EOP, tocopheryl acetate and retinol are added to the oil phase composed of caprylic / capric triglycerides and meadowfoam seed oil, and stirred at 35–90°C to dissolve and disperse. S2: The pre-degassed hydrogenated lecithin, cholesterol, glycerol and propylene glycol aqueous phase are slowly added to the oil phase at the same temperature at a ratio of oil phase:water phase = 1-1.5:0.8-1.2, and mixed with high shear stirring at 5000-8000 rpm to form a liquid liposome dispersion; S3: The dispersion is narrowed in particle size and distribution by microfluidic shearing and purified at ≤30°C. S4: The refined liquid dispersion is directly filled without the need for alcohol removal or drying.

[0013] Further, in step S1, the mass ratio of ceramide NP:AP:EOP is (40–60):(40–60):(1–5), preferably about 30:25:1.

[0014] Furthermore, in step S1, the stirring speed is 300–500 r / min and the stirring time is 5–10 min.

[0015] Furthermore, in step S2, the stirring speed is 300–500 r / min and the stirring time is 5–10 min.

[0016] Furthermore, in step S2, the pH of the aqueous phase is 5.0–6.5, preferably 5.3–5.9.

[0017] Furthermore, in step S3, the microjet high-pressure homogenization is 10000–20000 Pa, and the cycle is repeated 2–5 times.

[0018] Furthermore, the entire preparation process is carried out under conditions of light protection and an inert atmosphere.

[0019] This invention provides a biomimetic liposome encapsulating retinol with ceramide, its preparation method, and its application. This liposome, by precisely mimicking the natural lipid composition and structure of the stratum corneum of human skin, constructs a retinol delivery system with high stability, good skin compatibility, and significant anti-aging effects.

[0020] Regarding the composition of liposomes, this invention innovatively employs a biomimetic compounding of multiple subtypes of ceramides (NP, AP, EOP) with cholesterol and hydrogenated lecithin in a specific mass ratio (4-6:2-4:4-6). This ratio, determined through extensive experimental verification, most accurately mimics the natural lipid composition of the stratum corneum of healthy skin. Ceramide NP, the most abundant ceramide subtype in the skin, is primarily responsible for forming a stable layered structure; ceramide AP enhances the density of the lipid bilayer; and ceramide EOP, with its unique esterified ω-hydroxyl structure, further strengthens the stability and barrier function of the layered structure. The synergistic effect of the three ceramides, together with an appropriate ratio of cholesterol and hydrogenated lecithin, constructs a highly ordered layered liquid crystal film structure, which not only provides an ideal storage environment for retinol but also significantly enhances the stability of the liposomes themselves.

[0021] Regarding the solvent system, this invention preferably uses a composite oil phase composed of caprylic / capric triglyceride and meadowfoam seed oil. Caprylic / capric triglyceride, as a high-quality medium-chain fatty acid ester, not only effectively dissolves fat-soluble active ingredients such as retinol but also possesses excellent skin permeability; while meadowfoam seed oil is rich in long-chain fatty acids, and its excellent antioxidant properties provide additional stability and protection for the system. This specific combination of the two oils, at the optimal ratio, ensures the full dissolution of retinol and enhances the oxidative stability of the entire system through complementary effects.

[0022] The aqueous phase system consists of propylene glycol and glycerol in a specific ratio. Propylene glycol, as a hydrophilic solvent, promotes the dispersion of lipid components in the aqueous phase and regulates the osmotic pressure of the system; while glycerol, through its strong moisturizing effect, maintains the integrity of the liposome structure and prevents aggregation or sedimentation during storage. The unique feature of this aqueous phase system is that it can directly form stable nanoscale liquid liposome dispersions without the need for alcohol removal or drying, greatly simplifying the production process.

[0023] In terms of preparation process, this invention employs a meticulously designed procedure. First, ceramides NP, AP, EOP, tocopheryl acetate, and retinol are dissolved at 35-90°C in an oil phase composed of caprylic / capric triglycerides and meadowfoam seed oil, ensuring that all lipid components are fully dissolved and uniformly dispersed. Then, a pre-degassed aqueous phase of hydrogenated lecithin, cholesterol, glycerol, and propylene glycol is slowly added to the oil phase at the same temperature, at a ratio of 1-1.5:0.8-1.2 (oil phase to water ratio), while simultaneously mixing at a high shear rate of 5000-8000 rpm to form a preliminary liposome dispersion.

[0024] Next, the obtained dispersion was subjected to microfluidic shearing technology to homogenize the particle size. The mixture was cyclically subjected to a pressure of 10,000-20,000 Pa for 2-5 cycles to narrow the liposome particle size distribution, ultimately obtaining nanoliposomes with an average particle size D50 of 50-300 nm, preferably 80-200 nm. The entire process was carried out under light-protected and inert atmosphere protection to ensure that retinol was not degraded during the preparation process.

[0025] Compared with existing technologies, this invention has multiple technical advantages: the biomimetic layered liquid crystal structure significantly improves the light, heat, and oxygen stability of retinol, effectively delaying its degradation process; the skin-compatible ceramide encapsulation system greatly reduces the skin irritation of retinol, reducing adverse reactions such as burning and erythema during use; while achieving a high active ingredient loading of 1.0-3.0 wt%, it eliminates the cumbersome and costly dealcoholization or freeze-drying steps in traditional liposome preparation, greatly simplifying the production process and improving process efficiency.

[0026] The biomimetic ceramide-encapsulated retinol liposomes prepared in this invention can improve or prevent various skin problems such as photoaging, fine lines, dryness, roughness, damaged skin barrier, and dullness. They also possess multiple benefits, including inhibiting hyaluronidase activity, increasing stratum corneum hydration, and enhancing antioxidant protection. This liposome dispersion can be directly applied to various topical skin care formulations such as serums, lotions, creams, and ampoules, providing an ideal technical solution for developing highly effective and safe retinol anti-aging products.

[0027] The beneficial effects of this invention are as follows: This invention significantly improves the stability of retinol through biomimetic design, effectively delaying its photothermal degradation. Simultaneously, the liposomes utilize highly skin-compatible components for encapsulation, greatly reducing retinol irritation and adverse skin reactions. Its innovative preparation process eliminates traditional dealcoholization or freeze-drying steps, simplifying the production process and facilitating industrialization. The final product not only achieves efficient retinol loading and transdermal delivery but also synergistically repairs the skin barrier, collectively providing multiple anti-aging benefits such as improving photoaging, fine lines, and dry skin. Attached Figure Description

[0028] Figure 1 This is a particle size distribution diagram.

[0029] Figure 2 This is a comparison of HaCaT cell viability.

[0030] Figure 3 The value represents the hyaluronidase inhibition rate.

[0031] Figure 4 Comparison of lipofuscin fluorescence intensity in Caenorhabditis elegans.

[0032] Figure 5 To help Caenorhabditis elegans survive oxidative stress. Detailed Implementation

[0033] The present invention will be further described below with reference to embodiments, but this does not limit the invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods.

[0034] Example 1 A biomimetic liposome encapsulating retinol with ceramides is composed of the following raw materials in parts by weight: ceramide NP 2.6 wt%, ceramide AP 1.3 wt%, ceramide EOP 0.1 wt%, cholesterol 2.0 wt%, meadowfoam seed oil 1.0 wt%, hydrogenated lecithin 4.50 wt%, retinol 2.00 wt%, tocopheryl acetate 1.5 wt%, caprylic / capric triglyceride 30.0 wt%, propylene glycol 3.0 wt%, glycerol 30.0 wt%, and water 22 wt%.

[0035] A biomimetic liposome encapsulating retinol with ceramide was prepared entirely under light-protected and inert atmosphere conditions. The specific preparation method includes the following steps: S1: Ceramides NP, AP, EOP, tocopheryl acetate and retinol were added to the oil phase composed of caprylic / capric triglycerides and meadowfoam seed oil, and dissolved and dispersed by stirring at 70°C for 30 min. S2: The pre-degassed hydrogenated lecithin, cholesterol, glycerol and propylene glycol aqueous phase are slowly added to the oil phase at the same temperature at a ratio of oil phase:water phase = 5:4. The pH of the aqueous phase is 5.5. The mixture is stirred at 8000 rpm with high shear to form a liquid liposome dispersion. S3: The dispersion is narrowed in particle size and distribution by high-pressure homogenization or microfluidic shearing, and the purification is completed at ≤30°C. The micro-jet high-pressure homogenization is 20000 Pa, and the cycle is repeated twice. S4: The refined liquid dispersion is directly filled without the need for alcohol removal or drying.

[0036] Example 2 Liposomes containing retinol encapsulated by a single ceramide NP are composed of the following ingredients in parts by weight: ceramide NP 4.0 wt%, cholesterol 2.0 wt%, meadowfoam seed oil 1.0 wt%, hydrogenated lecithin 4.50 wt%, retinol 2.00 wt%, tocopheryl acetate 1.5 wt%, caprylic / capric triglyceride 30.0 wt%, propylene glycol 3.0 wt%, glycerol 30.0 wt%, and water 22 wt%.

[0037] Liposomes containing retinol encapsulated by a single ceramide NP were prepared entirely under light-protected and inert atmosphere conditions. The specific preparation method includes the following steps: S1: Ceramide NP, tocopheryl acetate and retinol were added to the oil phase composed of caprylic / capric triglycerides and meadowfoam seed oil, and dissolved and dispersed by stirring at 80°C for 30 min. S2: The pre-degassed hydrogenated lecithin, cholesterol, glycerol and propylene glycol aqueous phase are slowly added to the oil phase at the same temperature at a ratio of oil phase:water phase = 5:6. The pH of the aqueous phase is 5.5. The mixture is stirred at 5000 rpm with high shear to form a liquid liposome dispersion. S3: The dispersion is narrowed in particle size and distribution by high-pressure homogenization or microfluidic shearing, and the purification is completed at ≤30°C. The micro-jet high-pressure homogenization is 10000 Pa and is cyclic 5 times. S4: The refined liquid dispersion is directly filled without the need for alcohol removal or drying.

[0038] Comparative Example 1: Same formulation as Example 1, except that ceramides NP / AP / EOP are removed and replaced with caprylic / capric triglycerides.

[0039] Experimental Example 1: HaCaT Cell Viability (MTT) Grouping: Example 1, Example 2, Comparative Example 1, Blank Control Exposure concentration / time: The sample was diluted with DMEM medium containing DMSO-glycerol and incubated with cells for 24 h before cell viability was monitored.

[0040] Result: As Figure 2 As shown, Examples 1 and 2 showed no cytotoxicity at concentrations up to 1000 mg / L. At lower concentrations, they exhibited some cell viability enhancement, and the retinol sample encapsulated in the biomimetic ceramide system (Example 1) showed a better enhancement than the retinol sample encapsulated in a single ceramide NP (Example 2). At a concentration of 31.25 mg / L (P < 0.005), Examples 1 and 2 enhanced cell viability by 108.3% and 103.1%, respectively; while Control Example 1 showed cytotoxicity at a concentration of 125 mg / L, demonstrating a significant difference.

[0041] Experimental Example 2: Hyaluronidase Inhibition Method: Hyaluronidase Add sodium hyaluronate to react with hyaluronidase, dilute the sample with acetate buffer solution, and co-incubate. The absorbance of the reaction system at 540 nm was measured. Result: As Figure 3As shown, Examples 1, 2, and Control Example 1 all exhibited good hyaluronidase inhibition effects. Examples 1 and 2, at a 10-fold dilution, showed inhibition rates >60% against hyaluronidase. Control Example 1, at a 10-fold dilution, showed an inhibition rate >40% against hyaluronidase. At an 80-fold dilution, Examples 1 and 2 showed inhibition rates of 15.68% and 7.59% against hyaluronidase, respectively, indicating that at low concentrations, Example 1 had a better inhibitory effect on hyaluronidase than Example 2. However, the inhibition rate of Control Example 1 after an 80-fold dilution showed no significant difference compared to the control group.

[0042] Experimental Example 3: Lipofusin in Caenorhabditis elegans Lipofuscin assays are often used to assess the degree of aging and anti-aging effects. It is a fluorescent "senile pigment" that accumulates with aging. The content of lipofuscin can be quantitatively analyzed by fluorescence microscopy, and its accumulation level usually reflects the degree of cell damage and aging.

[0043] Model: Nematode synchronization, L4 stage nematodes were continuously intervened in each group of samples for 10 days.

[0044] Nematodes were anesthetized with sodium azide and transferred to a 2% agarose gel pad. Fluorescence images were acquired under a fluorescence microscope, and the average fluorescence value was calculated.

[0045] Result: As Figure 4 As shown, both Example 1 and Control Example 1 achieved a decrease in lipofuscin fluorescence. The degree of lipofuscin aggregation is an important indicator of the degree of aging. Compared with the control group, the lipofuscin content in the sample group was significantly reduced, indicating that the samples had a significant anti-aging effect.

[0046] Experimental Example 4: Oxidative Stress in Caenorhabditis elegans Model: Nematode synchronization, L4 stage nematodes were selected and placed on NGM plates in each group.

[0047] After two days of continuous administration, the culture medium without E. coli was preheated at 35 ℃ for 1 h. Then, 20 nematodes were picked from each group and placed in the culture medium and cultured at 35 ℃ for the experiment (the blank group was cultured at room temperature).

[0048] The survival status of nematodes was monitored at fixed time intervals until all nematodes died. The average lifespan was then calculated.

[0049] Results: The survival rate of Example 1 and Control Group 1 was improved (see details). Figure 5 See Table 1. Compared to the control group, the average lifespan of the hydrogen peroxide-induced model group was significantly reduced, indicating that oxidation has a serious impact on the lifespan of nematodes. Compared to the model group, the average lifespan of the sample groups was improved, especially in Example 1.

[0050] Table 1 Oxidative stress data of Caenorhabditis elegans Experimental Example 5: Stability and Release High-temperature accelerated test: After 4 weeks at 45°C / 75%RH, the retinol content (1.92% in Example 1; 1.24% in Control Example 1) is shown in Table 2.

[0051] Table 2. Statistical analysis of retinol content changes over time in Example 1 and Control Example 1 at high temperature (45°C) Photostability test: After 4 weeks of exposure to light at 25°C / 75%RH, the retinol content (1.90% in Example 1; 1.02% in Control Example 1) is shown in Table 3.

[0052] Table 3. Statistical analysis of retinol content changes over time in Example 1 and Control Example 1 under light conditions. After 3–6 freeze-thaw cycles, the particle size did not change significantly.

[0053] Experimental Example 6: Application Case (Topical Formulation of Liquid Liposomes) Essence: Add 10 wt% of the dispersion from Example 1, and finally prepare approximately 0.2 wt% retinol, pH 5.5, packaged in a light-protected container.

[0054] Emulsions / creams: Add 1–5 wt% liposome dispersion, emulsification temperature ≤35°C, gentle shearing to avoid membrane breakage.

[0055] Ampoules / Sprays: Liquid liposomes can be directly dispensed or formulated into ready-to-use systems with aqueous solutions. This invention employs a direct hydration-homogenization / microfluidic process, eliminating the need for alcohol-based solubilization and removal, and removing any drying steps. It directly yields liquid liposome dispersions, featuring a simple process, low energy consumption, and easy scale-up. Combined with data from HaCaT, HAase, and Caenorhabditis elegans, it demonstrates excellent stability, sustained release, and efficacy, making it suitable for large-scale production and multi-dosage formulations for topical application.

[0056] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A biomimetic ceramide-encapsulated retinol liposome, characterized in that, It is composed of the following ingredients in parts by weight: ceramide NP 1.0–3.0 wt%, ceramide AP 1.0–3.0 wt%, ceramide EOP 0.05–0.5 wt%, cholesterol 1.0–3.0 wt%, meadowfoam seed oil 0.50–2.0 wt%, hydrogenated lecithin 3.0–10.0 wt%, retinol 1.0–3.0 wt%, tocopheryl acetate 0.50–2.50 wt%, caprylic / capric triglyceride (MCT) 15.0–45.0 wt%, propylene glycol 1.0–5.0 wt%, glycerol 15.0–45.0 wt%, and the balance being water.

2. The biomimetic ceramide-encapsulated retinol liposome according to claim 1, characterized in that, The retinol content is 1.0–3.0 wt%, preferably 2.0 wt%.

3. The biomimetic ceramide-encapsulated retinol liposome according to claim 1, characterized in that, The average particle size D50 of the raw material is 50–300 nm, preferably 80–200 nm.

4. The biomimetic ceramide-encapsulated retinol liposome according to claim 1, characterized in that, The cholesterol and hydrogenated lecithin are in a specific mass ratio of 4-6:2–4:4–6.

5. The biomimetic ceramide-encapsulated retinol liposome according to claim 1, characterized in that, The method for preparing the liposomes includes the following steps: S1: Ceramides NP, AP, EOP, tocopheryl acetate and retinol are added to the oil phase composed of caprylic / capric triglycerides and meadowfoam seed oil, and stirred at 35–90°C to dissolve and disperse. S2: The pre-degassed hydrogenated lecithin, cholesterol, glycerol and propylene glycol aqueous phase are slowly added to the oil phase at the same temperature at a ratio of oil phase:water phase = 1-1.5:0.8-1.2, and mixed with high shear stirring at 5000-8000 rpm to form a liquid liposome dispersion; S3: The dispersion is narrowed in particle size and distribution by microfluidic shearing and purified at ≤30°C. S4: The refined liquid dispersion is directly filled without the need for alcohol removal or drying.

6. The biomimetic ceramide-encapsulated retinol liposome according to claim 5, characterized in that, In step S1, the mass ratio of ceramide NP:AP:EOP is 40–60:40–60:1–5, preferably about 30:25:

1.

7. The biomimetic ceramide-encapsulated retinol liposome according to claim 5, characterized in that, In step S1, the stirring speed is 300–500 r / min and the stirring time is 5–10 min.

8. The biomimetic ceramide-encapsulated retinol liposome according to claim 5, characterized in that, In step S2, the stirring speed is 300–500 r / min, the stirring time is 5–10 min, and the pH of the aqueous phase is 5.0–6.5, preferably 5.3–5.

9.

9. A biomimetic ceramide-encapsulated retinol liposome according to claim 5, characterized in that, In step S3, the microjet high-pressure homogenization is 10000–20000 Pa, and the cycle is repeated 2–5 times.

10. A biomimetic ceramide-encapsulated retinol liposome according to any one of claims 1-9, characterized in that, The liposome dispersions (1–50 wt%) and cosmetically acceptable carriers described herein can be used to improve and prevent skin photoaging, fine lines or wrinkles, dryness and roughness, barrier damage and dullness, and can also be used to inhibit hyaluronidase activity, increase stratum corneum hydration and provide antioxidant protection.

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