Preparation method and application of a diglyceride nanostructured lipid carrier hydrogel

Abstract

This invention discloses a method for preparing a diglyceride nanostructured lipid carrier hydrogel, comprising the following steps: mixing vegetable oil and diglyceride at a mass ratio of 1:1-3 as phase A; using an aqueous solution of soybean lecithin, tea saponin, and glycerol as phase B; adding phase B to phase A, followed by emulsification, ultrasonic treatment, and finally cooling to room temperature to obtain a diglyceride nanostructured lipid carrier; adding the diglyceride nanostructured lipid carrier to the hydrogel and mixing to obtain the diglyceride nanostructured lipid carrier hydrogel. This invention also discloses the application of the above-mentioned diglyceride nanostructured lipid carrier hydrogel. The diglyceride nanostructured lipid carrier hydrogel of this invention not only has good sun protection, antioxidant, and anti-glycation properties, but can also encapsulate unstable cosmetic raw materials.

Description

Technical Field

[0001] This invention relates to the field of cosmetic preparation, and particularly to a method for preparing and applying a diglyceride nanostructured lipid carrier hydrogel. Background Technology

[0002] Vegetable oils are 95% triglycerides, but long-term consumption can easily lead to fat deposition and obesity. Triglycerides, due to their strong hydrophobicity, cannot encapsulate drugs, limiting their application in cosmetics. Diglycerides, because their metabolic pathway differs from triglycerides, do not cause fat deposition and are therefore highly favored. Vegetable oils naturally contain low levels of diglycerides; through structural modification, vegetable oils primarily containing diglycerides can be prepared. However, these diglycerides are currently only used as functional oils in food additives (Meng Xianghe, Mao Zhonggui, Gao Baojun, et al. Current Status of Diglyceride Applications. China Food Additives, 2002, (04): 58-61), and not in cosmetics. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the present invention aims to provide a diglyceride nanostructure lipid carrier hydrogel that not only has good sun protection, anti-oxidation and anti-glycation properties, but can also encapsulate unstable cosmetic raw materials.

[0004] Another object of the present invention is to provide the application of the above-mentioned diglyceride nanostructure lipid carrier hydrogel.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a diglyceride nanostructured lipid carrier hydrogel includes the following steps:

[0007] Vegetable oil and diglycerides were mixed at a mass ratio of 1:1-3 to form phase A; an aqueous solution containing soybean lecithin, tea saponin and glycerol was used as phase B; wherein, in phase B, the mass concentration of soybean lecithin was 1%-2%, the mass concentration of tea saponin was 0.5%-1%, and the mass concentration of glycerol was 4%-5%.

[0008] Phase B was added to phase A at a volume ratio of 1-3:1, followed by emulsification, ultrasonic treatment, and finally cooling to room temperature to obtain a diglyceride nanostructured lipid carrier.

[0009] Diglyceride nanostructured lipid carriers were added to the hydrogel at a mass ratio of 1:1-3, and the mixture was then used to obtain the diglyceride nanostructured lipid carrier hydrogel.

[0010] Preferably, the vegetable oil is at least one of soybean oil, peanut oil, tea oil, sunflower seed oil, olive oil, and rapeseed oil.

[0011] Preferably, the diglyceride is prepared as follows:

[0012] Fatty acids and glycerol are mixed at a molar ratio of 3-9:1. Novozym 435 enzyme, weighing 2%-3% of the fatty acid mass, is added and reacted at 55℃-65℃ and 0.3MPa-0.6MPa for 2-5 hours. After dissolving the crude product in hexane, the upper hexane phase is collected and evaporated to recover the hexane, yielding diglycerides.

[0013] Preferably, the fatty acid is at least one selected from caprylic acid, capric acid, lauric acid, palmitic acid, oleic acid, and linoleic acid.

[0014] Preferably, the hydrogel is prepared as follows:

[0015] A 1%–5% aqueous solution of carbomer 940 and a 10%–15% aqueous solution of glycerol were mixed at a volume ratio of 1:1–3; triethanolamine was added to neutralize the mixture to obtain a hydrogel; wherein the mass ratio of triethanolamine to carbomer was 1:0.5–2.

[0016] Preferably, the emulsification specifically involves emulsifying at a rotation speed of 3000-5000 r / min for 5-15 min.

[0017] Preferably, the ultrasound is specifically: 50-200W ultrasound treatment for 15-30 minutes.

[0018] Preferably, the mixing is specifically performed by mixing for 10 to 15 minutes under stirring conditions of 300 rpm to 500 rpm.

[0019] The application of diglyceride nanostructured lipid carrier hydrogel, which is prepared by the same method as described above, is used in the preparation of cosmetics.

[0020] Preferably, the cosmetic is a cosmetic with one or more functions including sun protection, anti-oxidation, and anti-glycation.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] (1) In this invention, diglycerides are prepared from fatty acids and glycerol under the action of enzymes. Then, diglycerides are compounded with vegetable oil and emulsified by ultrasonication to obtain a diglyceride nanostructured lipid carrier. Finally, a hydrogel is prepared using triethanolamine and carbomer to coat the diglyceride nanostructured lipid carrier, resulting in a well-dispersible diglyceride nanostructured lipid carrier hydrogel. The prepared hydrogel has good sun protection, antioxidant, and anti-glycation properties.

[0023] (2) The hydrogel of the present invention has good drug loading effect and improves the stability of unstable cosmetic raw materials.

[0024] (3) The preparation process of this invention is simple and suitable for industrial production. Attached Figure Description

[0025] Figure 1 The results show the determination of diglyceride content in the diglyceride product prepared in Example 1 of the present invention.

[0026] Figure 2 The results show the determination of diglyceride content in the diglyceride product prepared in Example 2 of the present invention.

[0027] Figure 3 The results show the determination of diglyceride content in the diglyceride product obtained in Example 3 of the present invention.

[0028] Figure 4 The results show the determination of diglyceride content in the diglyceride product prepared in Example 4 of the present invention.

[0029] Figure 5 The results show the determination of diglyceride content in the diglyceride product prepared in Example 5 of the present invention.

[0030] Figure 6 The results show the determination of diglyceride content in the diglyceride product prepared in Example 6 of the present invention.

[0031] Figure 7 The results are the ultraviolet absorption capacity test results of Examples 1 to 6 of the present invention.

[0032] Figure 8 The results are the anti-glycation strength test results of Examples 1 to 6 of the present invention.

[0033] Figure 9 The results show the comparison of the sun protection UV absorption capacity of the caprylic acid diglyceride nanostructured lipid carrier (C8-NLC) and the caprylic acid diglyceride nanostructured lipid carrier hydrogel (HG-C8-NLC) prepared in Example 1 of the present invention. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0035] Example 1

[0036] (1) Caprylic acid and glycerol were mixed at a molar ratio of 3:1, and 2% (by weight) of Novozym 435 enzyme (by weight of fatty acids) was added. The mixture was reacted at 55°C and 0.3 MPa for 5 h. After dissolving the crude product in hexane (by weight of fatty acids), the upper hexane phase was collected, and the hexane was evaporated to recover the product, yielding diglyceride.

[0037] (2) Soybean oil and diglycerides were mixed at a mass ratio of 1:1 to form phase A. A 1% soybean lecithin, 0.5% tea saponin, and 4% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 1:1) at 50°C and emulsified at 3000 r / min for 15 min. Then, the mixture was ultrasonicated at 200 W for 15 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0038] (3) Mix 1% carbomer 940 and 10% glycerol aqueous solution in a volume ratio of 1:1, and add triethanolamine in a mass ratio of 1:0.5 with carbomer to neutralize to neutral, thus forming a hydrogel;

[0039] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:1, and mix at 300 rpm for 15 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0040] Example 2

[0041] (1) Decanoic acid and glycerol were mixed at a molar ratio of 9:1, and 3% (by weight) of Novozym 435 enzyme (by weight of fatty acid) was added. The mixture was reacted at 65°C and 0.6 MPa for 2 hours. After dissolving the crude product in hexane (by weight of fatty acid) in 5 times its mass, the upper hexane phase was collected, and the hexane was evaporated to recover the product, yielding diglyceride.

[0042] (2) Peanut oil and diglycerides were mixed at a mass ratio of 1:2 to form phase A. A 2% soybean lecithin, 1% tea saponin, and 5% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 3:1) at 70°C and emulsified at 5000 r / min for 5 min. Then, the mixture was ultrasonicated at 50 W for 30 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0043] (3) Mix 5% carbomer 940 and 15% glycerol aqueous solution at a volume ratio of 1:3, add triethanolamine at a mass ratio of 1:2 with carbomer to neutralize to neutral, and a hydrogel is formed.

[0044] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:3, and mix at 500 rpm for 10 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0045] Example 3

[0046] (1) Lauric acid and glycerol were mixed at a molar ratio of 5:1, and 2.5% of Novozym435 enzyme by mass of fatty acids was added. The mixture was reacted at 60℃ and 0.4MPa for 3 hours. After dissolving the crude product in hexane at a mass of 4 times that of fatty acids, the upper hexane phase was taken and the hexane was evaporated to recover the product, thus obtaining diglyceride.

[0047] (2) Tea oil and diglycerides were mixed at a mass ratio of 1:2 to form phase A. A 1.5% soybean lecithin, 0.6% tea saponin, and 4.5% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 2:1) at 60℃ and emulsified at 4000 r / min for 10 min. Then, the mixture was ultrasonicated at 100 W for 20 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0048] (3) Mix 3% carbomer 940 and 12% glycerol aqueous solution at a volume ratio of 1:2, and add triethanolamine at a mass ratio of 1:1 with carbomer to neutralize to neutral, thus forming a hydrogel.

[0049] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:2, and mix at 400 rpm for 12 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0050] Example 4

[0051] (1) Palmitic acid and glycerol were mixed at a molar ratio of 6:1, and 2% (by weight) of Novozym 435 enzyme (by weight of fatty acids) was added. The mixture was reacted at 65°C and 0.5 MPa for 4 hours. After dissolving the crude product in hexane at a mass ratio of 3 times that of fatty acids, the upper hexane phase was collected, and the hexane was evaporated to recover the product and obtain diglyceride.

[0052] (2) Sunflower seed oil and diglycerides were mixed at a mass ratio of 1:1.5 to form phase A. A 1.5% soybean lecithin, 0.8% tea saponin, and 4% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 1.5:1) at 55°C and emulsified at 3000 r / min for 12 min. Then, the mixture was ultrasonicated at 150 W for 20 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0053] (3) Mix 4% carbomer 940 and 10% glycerol aqueous solution at a volume ratio of 1:1.5, add triethanolamine at a mass ratio of 1:1.5 to carbomer to neutralize to neutral, and a hydrogel is formed.

[0054] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:1.5, and mix at 300 rpm for 12 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0055] Example 5

[0056] (1) Oleic acid and glycerol were mixed at a molar ratio of 4:1, and 3% of Novozym 435 enzyme by weight of fatty acids was added. The mixture was reacted at 55°C and 0.3 MPa for 5 hours. After dissolving the crude product in hexane at 5 times the weight of fatty acids, the upper hexane phase was taken and the hexane was evaporated to recover the product, thus obtaining diglyceride.

[0057] (2) Olive oil and diglycerides were mixed at a mass ratio of 1:1 to form phase A. A 1% soybean lecithin, 1% tea saponin, and 4% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 1:1) at 50°C and emulsified at 5000 r / min for 8 min. Then, the mixture was ultrasonicated at 100 W for 18 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0058] (3) Mix 3% carbomer 940 and 10% glycerol aqueous solution at a volume ratio of 1:2, and add triethanolamine at a mass ratio of 1:1 with carbomer to neutralize to neutral, thus forming a hydrogel;

[0059] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:2, and mix at 300 rpm for 12 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0060] Example 6

[0061] (1) Linoleic acid and glycerol were mixed at a molar ratio of 7:1, and 2% (by weight) of Novozym 435 enzyme (by weight of fatty acids) was added. The mixture was reacted at 60°C and 0.5 MPa for 3 hours. After dissolving the crude product in hexane (4 times the weight of fatty acids), the upper hexane phase was collected, and the hexane was evaporated to recover the product, yielding diglyceride.

[0062] (2) Rapeseed oil and diglycerides were mixed at a mass ratio of 1:2 to form phase A. A 2% soybean lecithin, 0.5% tea saponin, and 4% glycerol aqueous solution were used as phase B. Phase B was added to phase A (phase B to phase A volume ratio of 2:1) at 60℃ and emulsified at 3500 r / min for 11 min. Then, the mixture was ultrasonicated at 80 W for 18 min and finally cooled to room temperature to obtain the diglyceride nanostructure lipid carrier.

[0063] (3) Mix 3% carbomer 940 and 11% glycerol aqueous solution at a volume ratio of 1:2, add triethanolamine at a mass ratio of 1:2 with carbomer to neutralize to neutral, and a hydrogel is formed.

[0064] (4) Add the diglyceride nanostructure lipid carrier obtained in step (2) to the hydrogel obtained in step (3) at a mass ratio of 1:3, and mix at 400 rpm for 12 min to obtain the diglyceride nanostructure lipid carrier hydrogel.

[0065] Test 1

[0066] Determination of diglyceride content in the diglyceride products prepared in Examples 1 to 6.

[0067] Method: 50 μL of diglycerides and 1 mL of acetone were measured into a 2 mL centrifuge tube. The mixture was ultrasonically vibrated for 1 min to ensure homogeneity. The liquid was then filtered through a membrane to remove non-nano-sized particles. Liquid chromatography was used, with acetonitrile-acetic acid as mobile phase A and isopropanol as mobile phase B. The flow rate was 1.2 m / h, and the samples were injected at 45 °C. The contents of the six diglycerides were obtained, and the results are as follows: Figures 1-6 As shown.

[0068] Results: In Example 1, the peak eluted at 2–3 min was caprylic acid diglyceride (C8-DAG), with a content of 73.09%. In Example 2, the peak eluted at 4–5 min was decanoic acid diglyceride (C10-DAG), with a content of 78.41%. In Example 3, the peak eluted at 5–10 min was lauric acid diglyceride (C12-DAG), with a content of 76.66%. In Example 4, the peak eluted at 20–25 min was palmitic acid diglyceride (C14-DAG), with a content of 62.20%. In Example 5, the peak eluted at 14–30 min was oleic acid diglyceride (C18:1-DAG), with a content of 81.26%. In Example 6, the peak eluted at 10–20 min was linoleic acid diglyceride (C18:2-DAG), with a content of 80.68%.

[0069] Test 2

[0070] The particle size, PDI, and zeta potential of the diglyceride nanostructured lipid carriers (NLCs) prepared in Examples 1 to 6 were measured, and the results are shown in Table 1.

[0071] Method: Weigh 0.1g of each sample, add 20ml of water, and sonicate for 1min. Measure the particle size using a Zetasizer ULTRA nanoparticle size analyzer.

[0072] Results: With increasing carbon chain length, the system viscosity increased, resulting in larger sample particle size. Conversely, with increasing double bond number, the system viscosity decreased, resulting in larger sample particle size. All six samples had particle sizes within the range of 70-250 nm, and absolute potential values ​​above 20 mV, indicating relatively stable systems that meet the basic requirements of NLC.

[0073] Table 1

[0074]

[0075]

[0076] Test 3

[0077] Sunscreen test of the diglyceride nanostructured lipid carrier hydrogels prepared in Examples 1 to 6.

[0078] Methods: 0.1 g of each of the six samples was weighed and added to 200 ml of water for ultrasonic agitation. A UV spectrophotometer was used to scan the samples within the wavelength range of 200-400 nm.

[0079] Result: As Figure 7 As shown, the diglyceride nanostructured lipid carrier hydrogels prepared in Examples 1 to 6 all exhibit strong UV absorption capabilities. With increasing carbon chain length, the sun protection ability decreases, while with increasing double bond number, the sun protection ability increases. The caprylic / capric diglyceride nanostructured lipid carrier hydrogel demonstrates the best sun protection performance.

[0080] Test 4

[0081] The antioxidant test results of the diglyceride nanostructured lipid carrier hydrogels prepared in Examples 1 to 6 are shown in Table 2.

[0082] Method: Preparation of DPPH alcohol solution: Accurately weigh 0.00788g of DPPH drug, dissolve it in 99% anhydrous ethanol, and make up to 100mL. Shake well to prepare a 2mmol / L DPPH solution and place it in a light-proof cabinet for later use.

[0083] Sample solution preparation: Weigh 0.2g of each of the six samples into a 10mL centrifuge tube, and add deionized water to the 10mL mark to prepare a 20mg / mL sample solution. Dilute sequentially to 15mg / mL, 10mg / mL, and 5mg / mL. Number the four concentration gradients of the six samples from smallest to largest as 1 to 4, and conduct four parallel experiments.

[0084] Accurately pipette 2.0 mL of 2 mmol / L DPPH ethanol solution into a 4 mL centrifuge tube. Then, accurately pipette 2.0 mL of the sample solution, mix thoroughly, and incubate at 37°C for 30 min. Measure the absorbance (A) at 517 nm. i Similarly, after thoroughly mixing 2.0 mL of the sample solution with 2.0 mL of 99% anhydrous ethanol, the absorbance A at 517 nm was measured. j Similarly, after thoroughly mixing 2.0 mL each of the DPPH ethanol solution and 99% anhydrous ethanol, the absorbance A0 at 517 nm was measured. The scavenging rate of each test solution for DPPH free radicals was calculated using the following formula:

[0085]

[0086] In the formula: A0 is the absorbance of the blank group; A i A represents the absorbance of the experimental group; j This represents the absorbance of the sample solution itself.

[0087] Results: The diglyceride nanostructured lipid carrier hydrogels prepared in Examples 1 to 6 all exhibited certain free radical scavenging capabilities. The antioxidant capacity decreased with increasing carbon chain length, while it increased with increasing double bond number. The linoleic acid diglyceride nanostructured lipid carrier hydrogel demonstrated the best antioxidant performance.

[0088] Table 2

[0089] 20mg / ml 15mg / ml 10mg / ml 5mg / ml C8 22.68％ 16.93％ 16.26％ 5.25％ C10 19.62％ 15.95％ 13.81％ 4.99％ C12 14.42％ 13.44％ 11.19％ 4.60％ C16 12.15％ 11.52％ 10.09％ 4.39％ C18:1 22.56％ 17.34％ 14.54％ 4.07％ C18:2 23.68％ 17.94％ 14.67％ 7.68％

[0090] Test 5

[0091] Anti-glycation test of the diglyceride nanostructured lipid carrier hydrogels prepared in Examples 1 to 6.

[0092] Method: Reagent preparation

[0093] 0.1 mol / L, pH 7.4 PBS sterilization buffer: Take 4.0 g sodium chloride, 0.1 g potassium dihydrogen phosphate, 0.1 g potassium chloride, 1.44 g disodium hydrogen phosphate dodecahydrate, and 1.48 g EDTA-2Na, dissolve them in distilled water, add 5 mL of penicillin and streptomycin antibiotic solution, and bring the volume to 500 mL with distilled water and shake well.

[0094] 40g / L bovine serum albumin: Take 4g of bovine serum albumin, bring the volume to 100mL with PBS sterile buffer, and shake well.

[0095] 2 mol / L glucose: Take 19.8 g of glucose, bring the volume to 50 mL with PBS sterilization buffer, and shake well.

[0096] An in vitro non-enzymatic saccharification reaction system for proteins was established using bovine serum albumin and glucose. Under aseptic conditions, 2 mL of 2 mol / L glucose was added to a 10 mL volumetric flask, followed by 5 mL of 40 g / L bovine serum albumin, to achieve a final concentration of 20 g / L for bovine serum albumin and 400 mmol / L for glucose. The mixture was then incubated in a 37°C constant temperature drying oven in the dark.

[0097] Preparation of test solutions (20 mg / mL): Accurately weigh 0.4 g of each of the six test samples, then dilute each sample to 20 mL and shake well.

[0098] Experimental procedure:

[0099] Under relatively sterile conditions, a saccharification system consisting of 20 g / L bovine serum albumin solution and 400 mmol / L glucose solution was used. Control groups were set up as follows: (1) a complete saccharification system without the test solution; (2) a control group containing only bovine serum albumin; (3) a saccharification system with the test solution but without bovine serum albumin; (4) a saccharification system with the test solution but without glucose; and (5) a complete saccharification system with the drug and the test solution. Six parallel test solutions were used, each containing one of six diglycerides (NLC-HG), with a final concentration of 10 mg / ml. The solutions were incubated in a sterile, light-protected oven at 37°C.

[0100] After incubating the control reaction system in the dark for 40 days, the fluorescence intensity F of each group of reaction solutions was measured using a fluorescence spectrophotometer under the conditions of excitation wavelength 370 nm, emission wavelength 440 nm, and slit width 5 nm. Each experiment was performed in triplicate, and the experimental data were taken as mean ± standard deviation (x ± s).

[0101] After 40 days, the fluorescence intensity F of each tube was measured according to the following experimental method, and the inhibition rate of AGEs products was calculated according to the following formula.

[0102]

[0103] The results are as follows Figure 8 As shown, overall, the anti-glycation ability decreases with increasing carbon chain length. Similarly, the anti-glycation ability decreases with increasing double bond number. Among the six diglycerides prepared under the same conditions, decanoic acid diglyceride has a higher content than caprylic acid diglyceride. Therefore, although the carbon chain length increases, the increased diglyceride content allows for greater reaction with amino acids, inhibiting the production of advanced glycation end products (AGEs). Thus, its anti-glycation strength is slightly higher than that of caprylic acid diglyceride. Furthermore, the palmitic acid diglyceride sample contains the most monoglycerides, resulting in more hydroxyl groups that react with amino acids to prevent AGEs formation, thus increasing its anti-glycation strength. Therefore, the decanoic acid diglyceride nanostructured lipid carrier hydrogel exhibits the best anti-glycation performance.

[0104] In summary, to achieve the combined properties of sun protection, anti-oxidation, and anti-glycation, caprylic acid diglyceride nanostructure lipid carrier hydrogel is the best choice.

[0105] Test 6

[0106] Determination of encapsulation efficiency and drug loading of diglyceride nanostructured lipid carriers prepared in Examples 1-6

[0107] Methods: In steps (2) of Examples 1-6, 1% tea polyphenols were added to phase B, while other steps remained unchanged, resulting in six types of diglyceride nanostructure lipid carriers loaded with tea polyphenols. 0.0100 g of sample was weighed, 2 mL of PBS solution was added, and the mixture was stirred thoroughly to form a sample solution. The solution was then centrifuged at 15000 r / min for 10 min in a high-speed centrifuge. The supernatant was filtered through a 0.22 μm filter membrane, and the absorbance of the filtrate at 540 nm was measured to calculate the encapsulation efficiency.

[0108] Weigh 0.0100g of sample, add 2mL of anhydrous methanol and mix well. After sonicating in an ultrasonic cell disruptor for 10min, place it in a high-speed centrifuge and centrifuge at 15000r / min for 20min. Filter the supernatant after centrifugation through a 0.22μm filter membrane, measure the absorbance of the filtrate at 540nm, and calculate the drug loading.

[0109]

[0110]

[0111] In the formula, Wp is the actual drug loading, Wm is the sample volume, and Qp is the initial amount of tea polyphenols added to the sample.

[0112] Results: The encapsulation efficiency and drug loading of the diglyceride nanostructured lipid carriers prepared in Examples 1-6 are shown in Table 3. The encapsulation efficiency was 84.92-93.44%, and the drug loading was 9.35-12.53%, indicating that the prepared diglyceride nanostructured lipid carriers can effectively encapsulate tea polyphenols.

[0113] Table 3 Encapsulation efficiency and drug loading of diglyceride nanostructured lipid carriers in Examples 1-6

[0114] Encapsulation efficiency (%) Drug loading (%) Example 1 87.43 9.35 Example 2 86.37 11.47 Example 3 89.15 12.53 Example 4 92.74 9.75 Example 5 93.44 10.45 Example 6 84.92 11.64

[0115] Test 7

[0116] Comparison of the sun protection, antioxidant, and anti-glycation properties of the diglyceride nanostructured lipid carrier (C8-NLC) and the caprylic / caprylic diglyceride nanostructured lipid carrier hydrogel (HG-C8-NLC) prepared in Example 1. Method: Repeated tests 3-5 times.

[0117] result:

[0118] 1. Sun protection performance:

[0119] The results are as follows Figure 9 As shown.

[0120] 2. Antioxidant properties are shown in Table 4.

[0121] Table 4

[0122] 20mg / ml 15mg / ml 10mg / ml 5mg / ml C8-NLC 22.68％ 16.93％ 16.26％ 5.25％ HG-C8-NLC 26.77％ 20.41％ 18.36％ 10.66％

[0123] 3. The anti-glycation properties are shown in Table 5.

[0124] Table 5

[0125] 10mg / ml 6mg / ml 4mg / ml C8-NLC 91.07％ 80.09％ 78.73％ HG-C8-NLC 98.55％ 97.55％ 95.22％

[0126] The data above shows that compared to caprylic / diglyceride nanostructured lipid carrier (C8-NLC), HG-C8-NLC, due to its larger particle size, exhibits slightly lower UV absorption, but its UV protection range is primarily between 280-400 nm, indicating minimal difference between the two. However, HG-C8-NLC demonstrates significantly greater antioxidant and anti-glycation properties than C8-NLC, especially at lower doses. This suggests that the performance of the diglyceride nanostructured lipid carrier is significantly enhanced after being formulated into a hydrogel, indicating a synergistic effect between the substances.

[0127] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a diglyceride nanostructured lipid carrier hydrogel, characterized in that, Includes the following steps: Vegetable oil and diglycerides are mixed at a mass ratio of 1:1-3 as phase A; an aqueous solution containing soybean lecithin, tea saponin, and glycerol is used as phase B; wherein, in phase B, the mass concentration of soybean lecithin is 1%-2%, the mass concentration of tea saponin is 0.5%-1%, and the mass concentration of glycerol is 4%-5%; the diglycerides are prepared as follows: fatty acids and glycerol are mixed at a molar ratio of 3-9:1, and Novozym 435 enzyme (2%-3% by mass of fatty acids) is added. The mixture is reacted at 55℃-65℃ and 0.3MPa-0.6MPa for 2-5 hours. After dissolving the crude product in hexane (3-5 times the mass of fatty acids), the upper hexane phase is collected, and the hexane is evaporated to obtain the diglycerides; the fatty acids are one of octanoic acid, capric acid, lauric acid, palmitic acid, oleic acid, and linoleic acid. Phase B was added to phase A at a volume ratio of 1-3:1, followed by emulsification, ultrasonic treatment, and finally cooling to room temperature to obtain a diglyceride nanostructured lipid carrier; the particle size of the diglyceride nanostructured lipid carrier was 70-250 nm. Diglyceride nanostructured lipid carriers were added to the hydrogel at a mass ratio of 1:1-3, and the mixture was then used to obtain the diglyceride nanostructured lipid carrier hydrogel.

2. The method for preparing the diglyceride nanostructured lipid carrier hydrogel according to claim 1, characterized in that, The vegetable oil is at least one of soybean oil, peanut oil, tea oil, sunflower seed oil, olive oil, and rapeseed oil.

3. The method for preparing the diglyceride nanostructured lipid carrier hydrogel according to claim 1, characterized in that, The hydrogel is prepared as follows: A 1%–5% (w / w) aqueous solution of carbomer 940 and a 10%–15% (w / w) aqueous solution of glycerol were mixed at a volume ratio of 1:1–3. Triethanolamine was added to neutralize the mixture to obtain a hydrogel. The mass ratio of triethanolamine to carbomer was 1:0.5–2.

4. The method for preparing the diglyceride nanostructured lipid carrier hydrogel according to claim 1, characterized in that, The emulsification process specifically involves emulsifying at a speed of 3000-5000 r / min for 5-15 minutes.

5. The method for preparing the diglyceride nanostructured lipid carrier hydrogel according to claim 1, characterized in that, The ultrasound refers specifically to ultrasound treatment at 50-200W for 15-30 minutes.

6. The method for preparing the diglyceride nanostructured lipid carrier hydrogel according to claim 1, characterized in that, The mixing process specifically involves mixing for 10 to 15 minutes under stirring conditions of 300 to 500 rpm.

7. Application of diglyceride nanostructured lipid carrier hydrogel, wherein the diglyceride nanostructured lipid carrier hydrogel is prepared by the preparation method of the diglyceride nanostructured lipid carrier hydrogel according to any one of claims 1-6, characterized in that, Used in the preparation of cosmetics.

8. The application of the diglyceride nanostructured lipid carrier hydrogel according to claim 7, characterized in that, The cosmetics mentioned are cosmetics with one or more functions such as sun protection, anti-oxidation, and anti-glycation.

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