Liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate and method for preparing the same

Abstract

The application discloses a liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate and a preparation method thereof, and belongs to the technical field of daily-use chemicals.The raw materials of the liquid crystal emulsion include an alkyl glycoside sodium hydroxypropyl sulfonate solution and an oil phase; wherein the oil phase is selected from at least one of dodecanoic acid and hexadecanoic acid.The prepared liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate is hexagonal liquid crystal, can realize the encapsulation and stabilization of various active material cosmetic raw materials, and has good pH and temperature applicability.Meanwhile, the liquid crystal can effectively inhibit the oxidative degradation of the active material.The preparation process of the liquid crystal is simple and easy to operate, and has low requirements on equipment.

Description

A liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate and its preparation method thereof Technical Field

[0001] This invention belongs to the field of daily chemical technology, specifically relating to a liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate and its preparation method. Background Technology

[0002] Liquid crystals are ordered fluid structures that lie between solids and liquids, primarily consisting of lyotropic and thermotropic liquid crystals. Due to their diverse morphologies and highly ordered arrangement, liquid crystal phases have wide applications in active ingredient encapsulation, drug delivery, and other industrial fields. Surfactants, on the other hand, are water-soluble and possess long hydrophobic chains, enabling them to interact and form micelles. With increasing concentration, they also exhibit short-range order in their arrangement. Therefore, surfactants are excellent materials for preparing liquid crystals.

[0003] In daily life, surfactants are widely used in cleaning products, personal care products, and food. With the introduction of sustainable development strategies, people have begun to pay attention to ecological and environmental issues and the safety of daily necessities. Therefore, when using products containing surfactants, greater emphasis should be placed on their gentleness and biocompatibility. As a fourth-generation world-class surfactant, alkyl glycosides, in addition to good surface activity, also possess excellent gentleness and good biodegradability, meeting people's daily cleaning needs. However, with the development of the daily chemical industry, problems such as poor water solubility, insufficient detergency, and poor foaming properties of alkyl glycosides have gradually emerged. Therefore, it is necessary to improve these shortcomings while maintaining a gentleness comparable to alkyl glycosides through derivatization.

[0004] Sodium alkyl glycoside hydroxypropyl sulfonate is an anionic derivatized product based on alkyl glycosides. The China Cleaning Products Association has reported on its excellent surface and application properties, emphasizing its superior mildness compared to all current surfactants. Therefore, developing a liquid crystal containing sodium alkyl glycoside hydroxypropyl sulfonate is of significant practical importance for improving active ingredient loading, stability, and transdermal penetration. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate and its preparation method. The hexagonal liquid crystal system constructed from sodium alkyl glycoside hydroxypropyl sulfonate prepared by this invention achieves encapsulation and stabilization of several active cosmetic ingredients. The resulting liquid crystal exhibits good pH and temperature adaptability and effectively inhibits the oxidative degradation of active ingredients. The preparation process of this liquid crystal is simple and easy to implement, with low equipment requirements.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of this invention protects a liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate, the liquid crystal emulsion comprising the following raw materials: sodium alkyl glycoside hydroxypropyl sulfonate solution and an oil phase; the oil phase is selected from at least one of dodecanoic acid and hexadecanoic acid.

[0008] Preferably, the mass concentration of the sodium alkyl glycoside hydroxypropyl sulfonate solution is 13-16%; preferably, the mass concentration of the sodium alkyl glycoside hydroxypropyl sulfonate solution is 14-15%.

[0009] Preferably, the oil phase is dodecanoic acid.

[0010] Preferably, the mass ratio of the alkyl glycoside hydroxypropyl sulfonate sodium solution to the oil phase is 5-7:100.

[0011] Preferably, the mass ratio of the alkyl glycoside hydroxypropyl sulfonate sodium solution to the oil phase is 6-7:100.

[0012] A second aspect of this invention protects a method for preparing the liquid crystal emulsion described in the first aspect above, the method being as follows:

[0013] S1: Heat the oil phase to a molten state.

[0014] S2: Prepare a sodium alkyl glycoside hydroxypropyl sulfonate solution.

[0015] S3: After preheating the sodium alkyl glycoside hydroxypropyl sulfonate solution prepared in step S2, add it to the oil phase prepared in step S1 and stir for the first time. After homogenization, stir again and cool to room temperature to obtain a liquid crystal emulsion.

[0016] Preferably, in step S1, the heating temperature is 60-80°C.

[0017] Preferably, in step S2, the sodium alkyl glycoside hydroxypropyl sulfonate solution is obtained by dissolving sodium alkyl glycoside hydroxypropyl sulfonate in water; as described above.

[0018] Preferably, in step S3, the preheating temperature is 75-85℃, more preferably 80℃; the temperature of the first stirring is 75-85℃; the time is 3-5 min; and the speed is 350-450 r / min; preferably, the temperature of the first stirring is 80℃; the time is 3 min; and the speed is 400 r / min.

[0019] Preferably, in step S3, the homogenization speed is 12000 r / min and the time is 1-2 min.

[0020] The beneficial technical effects of this invention are as follows:

[0021] (1) In this invention, a liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate was successfully prepared by mixing sodium alkyl glycoside hydroxypropyl sulfonate with the oil phase and by limiting the raw materials and dosage.

[0022] (2) The sodium alkyl glycoside hydroxypropyl sulfonate used in this invention is natural and readily available, and is a green and mild surfactant; the liquid crystal emulsion formulation prepared has simple components and low preparation cost.

[0023] (3) By optimizing the formula, the present invention can obtain a weakly acidic hexagonal phase layered liquid crystal. The liquid crystal obtained has a good loading and penetration-promoting effect on some cationic active ingredients (such as ergothioneine) in cosmetics. At the same time, due to the special structure of the layered liquid crystal, it has a good encapsulation effect on unstable active ingredients (such as retinol and its derivatives) in cosmetics. Attached Figure Description

[0024] Figure 1 is a polarizing microscope image of the liquid crystal prepared in Example 1 of the present invention.

[0025] Figure 2 is a polarizing microscope image of the liquid crystal prepared in Example 4 of the present invention.

[0026] Figure 3 is a polarizing microscope photograph of the product of Comparative Example 1 of the present invention that cannot form liquid crystal.

[0027] Figure 4 is a polarizing microscope photograph of the product of Comparative Example 2 of the present invention that cannot form liquid crystal.

[0028] Figure 5 is a polarizing microscope photograph of the product of Comparative Example 3 of the present invention that cannot form liquid crystal.

[0029] Figure 6 shows the DSC curves of the liquid crystals prepared in Example 1 and Comparative Example 1 of this invention.

[0030] In the figure: (a) is the DSC curve of Example 1; (b) is the DSC curve of Comparative Example 1.

[0031] Figure 7 shows the permeation curves of liquid crystal-loaded ergothionein prepared in Examples 1 and 4 of this invention.

[0032] Figure 8 shows the degradation rate of liquid crystal-loaded retinol in Example 1 of the present invention.

[0033] Figure 9 shows the 1H NMR spectrum of sodium alkyl glycoside hydroxypropyl sulfonate used in this invention.

[0034] Figure 10 is a mass spectrum of sodium alkyl glycoside hydroxypropyl sulfonate used in the embodiments of the present invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] To address the problems of existing technologies, the present invention first provides a liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate, wherein the liquid crystal emulsion comprises the following raw materials: sodium alkyl glycoside hydroxypropyl sulfonate solution and an oil phase; wherein the oil phase is selected from at least one of dodecanoic acid and hexadecanoic acid.

[0037] It is understood that the microcrystalline emulsion described in this invention may also include other additives, such as glycerin, preservatives, fragrances, chelating agents, etc. This invention does not limit the types of additives; any additive that can achieve the purpose of this invention is within the scope of protection of this invention.

[0038] The sodium alkyl glycoside hydroxypropylsulfonate described in this invention can be prepared according to the method described in existing literature, namely Chang K, Jia B. Performance and mildness of alkyl glycoside hydroxypropylsulfonate. J Surfact Deterg. 2024.

[0039] In some embodiments of the present invention, the preparation method of the alkyl glycoside hydroxypropyl sulfonate sodium is as follows: APG1214 is dehydrated and dispersed in isopropanol. A certain mass of NaOH is added, and the mixture is sonicated for 30 min, followed by mechanical stirring in a water bath for 2 h of alkalization at a temperature of 65°C. Sodium 3-chloro-2-hydroxypropanesulfonate is dissolved in a water:isopropanol mixture of 4:1 and placed in a dropping funnel. Etherification is performed by titration at a rate of 1 drop / s for 8 h at a temperature of 70°C. After the reaction is complete, the mixture is separated. The lower yellow liquid is the crude product. After dialysis, the liquid is removed to obtain the crude APG1214 product. The product is washed repeatedly with anhydrous ethanol to constant weight to obtain alkyl glycoside hydroxypropyl sulfonate sodium, with a yield of 56.1%. The preparation route is as follows:

[0040]

[0041] Where R is -C 12 H 25 and / or -C 14 H 29 The product is a mixture containing R with different structures.

[0042] The NMR and mass spectrometry characterization of the prepared alkyl glycoside sodium hydroxypropyl sulfonate are shown in Figures 9-10.

[0043] Preferably, in some embodiments of the present invention, the alkyl glycoside hydroxypropyl sulfonate sodium used has a carbon chain of 12 and an average degree of polymerization of 1.4. More preferably, the alkyl glycoside hydroxypropyl sulfonate sodium used in the embodiments of the present invention is lauryl glucoside hydroxypropyl sulfonate sodium, which can be prepared by the above method.

[0044] In some embodiments, the liquid crystal emulsion comprises a sodium alkyl glycoside hydroxypropyl sulfonate solution and an oil phase; the oil phase is selected from at least one of dodecanoic acid and hexadecanoic acid. The present invention forms liquid crystals through the interaction of the oil phase with the alkyl glycoside hydroxypropyl sulfonate. Liquid crystals formed from dodecanoic acid are preferred. Hexadecanoic acid has a longer carbon chain and a larger head group area than dodecanoic acid, thus its interaction with the alkyl glycoside hydroxypropyl sulfonate is weaker, resulting in a less compact structural arrangement and a relatively poor liquid crystal structure, which cannot form a single liquid crystal.

[0045] In some embodiments, the mass concentration of the alkyl glycoside hydroxypropyl sulfonate sodium solution is 13-16%, including but not limited to 13%, 14%, 15%, and 16%; preferably, the mass concentration of the alkyl glycoside hydroxypropyl sulfonate sodium solution is 14-15%.

[0046] In some embodiments, the oil phase is dodecanoic acid. The dodecanoic acid used in this invention has the same carbon chain length as sodium alkyl glycoside hydroxypropyl sulfonate and also exhibits certain hydrophobic interactions. Furthermore, the carboxyl group of dodecanoic acid can form strong hydrogen bonds with the hydrophilic group of alkyl glycoside hydroxypropyl sulfonate, thereby promoting the formation of liquid crystals.

[0047] In some embodiments, the mass ratio of the sodium alkyl glycoside hydroxypropyl sulfonate solution to the oil phase is 100:5-7. This includes, but is not limited to, 100:5, 100:5.5, 100:6, 100:6.5, and 100:7; preferably, the mass ratio of the sodium alkyl glycoside hydroxypropyl sulfonate solution to the oil phase is 100:6-7.

[0048] It is understandable that liquid crystals cannot form when the ratio of the oil phase to the alkyl glycoside hydroxypropyl sulfonate solution and / or the concentration of the alkyl glycoside hydroxypropyl sulfonate solution is unsuitable. This is because changing these parameters affects the pH value of the liquid crystal raw material volume. When the organic phase accounts for a large proportion of the raw material system, the pH value is low, resulting in a large number of hydrogen ions distributed around the oxygen atoms of the hydroxyl and carboxyl groups, disrupting the hydrogen bond network and causing the liquid crystal to disappear. Conversely, when the organic phase accounts for a low proportion of the system, the pH value is high, and the carboxyl groups of the organic phase exist in the form of carboxylates, which exhibit electrostatic repulsion with the sulfonic acid anions of the alkyl glycoside hydroxypropyl sulfonate, leading to increased intermolecular spacing and thus the disappearance of the liquid crystal.

[0049] A second aspect of the present invention provides a method for preparing the liquid crystal emulsion described in the first aspect above, the method being as follows:

[0050] S1: Heat the oil phase to a molten state.

[0051] S2: Prepare a sodium alkyl glycoside hydroxypropyl sulfonate solution.

[0052] S3: After preheating the sodium alkyl glycoside hydroxypropyl sulfonate solution prepared in step S2, add it to the oil phase prepared in step S1 and stir for the first time. After homogenization, stir again and cool to room temperature to obtain a liquid crystal emulsion.

[0053] In some embodiments, in step S1, the heating temperature is 60-80°C, including but not limited to 60°C, 65°C, 70°C, 75°C, and 80°C, preferably 80°C.

[0054] In some embodiments, in step S2, the sodium alkyl glycoside hydroxypropyl sulfonate solution is obtained by dissolving sodium alkyl glycoside hydroxypropyl sulfonate in water.

[0055] In some embodiments, in step S3, the preheating temperature is 75-85℃, preferably 80℃; the temperature of the first stirring is 75-85℃; the time is 3-5 min; and the speed is 350-450 r / min; preferably, the temperature of the first stirring is 80℃; the time is 3 min; and the speed is 400 r / min.

[0056] In some embodiments, in step S3, the homogenization speed is 10000-12000 r / min and the time is 1-2 min; preferably, the homogenization speed is 12000 r / min and the time is 1 min.

[0057] It is understood that the liquid crystal emulsion prepared by this invention can be used in cosmetics, such as as a cosmetic formulation ingredient.

[0058] The present invention will be further described below through examples and other means.

[0059] Example 1

[0060] A liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate, the preparation method of which is as follows:

[0061] Weigh 0.6g of additive dodecanoic acid (B) and heat it to a molten state at 80℃ for later use.

[0062] Prepare an aqueous solution (A) of 9.4 g of alkyl glycoside hydroxypropyl sulfonate sodium (14.9 wt%) and preheat it to 80 °C. Specifically, the alkyl glycoside hydroxypropyl sulfonate used is lauryl glucoside hydroxypropyl sulfonate sodium.

[0063] 9.4 g of preheated 14.9 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten dodecanoic acid, and mechanically stirred at 400 rpm for 3 min. Then, the mixture was homogenized for 1 min at 12000 rpm using a high-speed homogenizer. After homogenization, the mixture was mechanically stirred and cooled to room temperature to obtain a liquid crystal sample. Observation under a polarizing microscope showed that the liquid crystal prepared in this example belonged to the hexagonal phase (H1) liquid crystal.

[0064] Example 2

[0065] A liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate, the preparation method of which is as follows:

[0066] Weigh 0.47g of additive dodecanoic acid (B) and heat it to a molten state at 75℃ for later use.

[0067] Prepare an aqueous solution (A) of 9.4 g of sodium alkyl glycoside hydroxypropyl sulfonate with a mass fraction of 14.0 wt%, and preheat it to 75 °C.

[0068] 9.4 g of preheated 14.0 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten dodecanoic acid, and mechanically stirred at 350 rpm for 4 min. Then, the mixture was homogenized for 2 min at 10000 rpm using a high-speed homogenizer. After homogenization, the mixture was mechanically stirred and cooled to room temperature to obtain a liquid crystal sample. Observation under a polarizing microscope showed that the liquid crystal prepared in this example belonged to the hexagonal phase (H1) liquid crystal.

[0069] Example 3

[0070] A liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate, the preparation method of which is as follows:

[0071] Weigh 0.658g of additive dodecanoic acid (B) and heat it to a molten state at 85℃ for later use.

[0072] Prepare an aqueous solution (A) of 9.4 g of alkyl glycoside hydroxypropyl sulfonate sodium (15.0 wt%) and preheat it to 85 °C.

[0073] 9.4 g of preheated 14.9 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten dodecanoic acid, and mechanically stirred at 450 rpm for 5 min. Then, the mixture was homogenized for 1.5 min at 11000 rpm using a high-speed homogenizer. After homogenization, the mixture was mechanically stirred and cooled to room temperature to obtain a liquid crystal sample. Observation under a polarizing microscope showed that the liquid crystal prepared in this example belonged to the hexagonal phase (H1) liquid crystal.

[0074] Example 4

[0075] A liquid crystal emulsion containing alkyl glycoside sodium hydroxypropyl sulfonate, the preparation method of which is as follows:

[0076] The preparation method is basically the same as in Example 1, except that the additive is replaced with hexadecanoic acid, while the rest remains unchanged.

[0077] Weigh 0.6g of additive hexadecanoic acid (B) and heat it to a molten state at 80℃ for later use.

[0078] Weigh 9.4 g of a preheated 14.9 wt% sodium alkyl glycoside hydroxypropyl sulfonate aqueous solution (A) and preheat it to 80 °C.

[0079] 9.4 g of preheated 14.9 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten hexadecanoic acid and mechanically stirred at 400 rpm for 3 min. Then, while still hot, it was homogenized in a high-speed homogenizer at 12000 rpm for 1 min. After homogenization, it was mechanically cooled to room temperature to obtain a liquid crystal emulsion. Observation under a polarizing microscope showed that the product obtained in this example was a mixed liquid crystal of hexagonal phase (H1) and layered phase (Lα). A single liquid crystal could not be obtained. This illustrates that the selection of additives is crucial to the formation of the liquid crystal proposed in this invention.

[0080] Comparative Example 1

[0081] The preparation method is basically the same as in Example 1, except that the additive in Example 1 is changed to stearic acid.

[0082] 0.6 g of additive octadecanoic acid (B) was weighed and heated to a molten state at 80 °C. 9.4 g of preheated 14.9 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to the molten octadecanoic acid, and the mixture was mechanically stirred at 400 rpm for 3 min. Then, while still hot, the mixture was homogenized in a high-speed homogenizer at 12000 rpm for 1 min. After homogenization, the mixture was mechanically stirred and cooled to room temperature. No liquid crystal formation was observed under a polarizing microscope, and the emulsion formed in subsequent samples broke down into two phases. This comparative example illustrates that the choice of additive is crucial to the formation of the liquid crystal proposed in this invention.

[0083] Comparative Example 2

[0084] An emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate is prepared as follows:

[0085] Weigh 0.3g of fatty acid additive dodecanoic acid (B) and heat it to a molten state at 80℃. Weigh 9.7g of preheated 7.2wt% sodium alkyl glycoside hydroxypropyl sulfonate aqueous solution (A) and preheat it to 80℃.

[0086] 9.7 g of preheated 7.2 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten dodecanoic acid, and mechanically stirred at 400 rpm for 3 min. Then, while still hot, it was homogenized in a high-speed homogenizer at 12000 rpm for 1 min. After homogenization, it was mechanically cooled to room temperature. No liquid crystal formation was observed under a polarizing microscope, and the emulsion formed in subsequent samples broke down into two phases. This comparative example illustrates that the concentration of the sodium alkyl glycoside hydroxypropyl sulfonate solution and its relative amount to dodecanoic acid, or the selection of the mixed mass concentration of sodium alkyl glycoside hydroxypropyl sulfonate and the additive, is crucial for the formation of the liquid crystal proposed in this invention.

[0087] Comparative Example 3

[0088] An emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate is prepared as follows:

[0089] Weigh 1.6g of additive dodecanoic acid (B) and heat it to a molten state at 80℃. Weigh 8.4g of preheated 4.8wt% sodium alkyl glycoside hydroxypropyl sulfonate aqueous solution (A) and preheat it to 80℃.

[0090] 8.4 g of preheated 4.8 wt% sodium alkyl glycoside hydroxypropyl sulfonate solution (A) was rapidly added to molten octadecanoic acid and mechanically stirred at 400 rpm for 3 min. Then, while still hot, the mixture was homogenized in a high-speed homogenizer at 12000 rpm for 1 min. After homogenization, the mixture was mechanically cooled to room temperature. No liquid crystal formation was observed under a polarizing microscope, and the emulsion formed in subsequent samples broke down into two phases.

[0091] This comparative example illustrates that the choice of the ratio of sodium alkyl glycoside hydroxypropyl sulfonate to the additive is crucial to the formation of the liquid crystal proposed in this invention.

[0092] Test example:

[0093] 1. Temperature stability test:

[0094] Experimental Method: The phase transition temperature was determined using a differential scanning calorimeter (DSC). The specific experimental procedure was as follows: 5 mg of samples from Examples 1 and 4 were weighed and placed in an aluminum crucible, then sealed. The samples were scanned using DSC within a range of 20–80 °C at a scan rate of 2 °C / min. -1 .

[0095] Analysis and Discussion: The test results are shown in the figure. Compared with the hybrid liquid crystal corresponding to Example 4, the hexagonal liquid crystal corresponding to Example 1 has a higher phase transition temperature and better stability, and can better meet the human body's temperature requirements.

[0096] 2. Transdermal performance testing:

[0097] Experimental Method: Ergothioneine is an endogenous salt with high solubility in water, which hinders its penetration into the skin. Since the samples in Comparative Examples 2 and 3 exhibited phase separation, rendering them meaningless for transdermal performance testing, samples from Examples 1 and 4 were selected, with aqueous solutions used as controls. Following the method in GB / T 27818-2011, an in vitro permeation experiment was conducted on the ergothioneine-loaded samples using a transdermal diffusion apparatus. The specific experimental procedure is as follows: First, the purchased pig ears were soaked in a 0.9 wt% sodium chloride solution. Then, excess hair, cartilage, and connective tissue under the epidermis and dermis were removed using scissors and a scalpel, and the ears were divided into regular squares. The stratum corneum of the pig ear skin was then brought into contact with the test liquid with the ear skin facing upwards, and fixed between the receiving and sample cells of the diffusion cell using stainless steel horseshoe clamps. A magnetic wave was added to the receiving cell, followed by the addition of the receiving liquid. The air in the receiving chamber was then expelled. The receiving liquid was a 30% ethanol-physiological saline solution. Two mL of ergothioneine-loaded sample was added to the sample cell and sealed with a paraffin membrane to ensure uniform contact with the skin. The test temperature was 37℃ and the rotation speed was 500 r·min. -1 The experiment lasted for 24 hours. The concentration of ergothioneine in the receiving solution was then measured using a microplate reader. The results are shown in Figure 7, where H1ergothioneine represents Example 1, H1&Lɑergothioneine represents Example 4, and Control represents the control group.

[0098] As shown in Figure 7, the hexagonal liquid crystal sample corresponding to Example 1 exhibits significantly better permeability for ergothioneine than the mixed liquid crystal sample corresponding to Example 4 and the control aqueous solution. This is because the hexagonal liquid crystal sample prepared using dodecanoic acid in Example 1 has an acidic pH, while ergothioneine is in cationic form, making it easily loaded into the hexagonal liquid crystal sample via electrostatic interactions. Furthermore, the hexagonal phase possesses a liquid crystal structure similar to skin lipids and has a lower viscosity than other types of liquid crystals, effectively improving skin tissue hydration and promoting ergothioneine absorption.

[0099] 3. Stability determination of active ingredients:

[0100] Experimental Methods: Retinyl propionate is a vitamin A compound with many conjugated double bonds and is highly sensitive to temperature and light. Since the samples in Comparative Examples 2 and 3 exhibited phase separation, rendering their stability tests meaningless, samples from Examples 1 and 4 were selected. The retinyl propionate-loaded samples were placed at 4°C, 25°C, 37°C, and 50°C. A 1,2-pentanediol solution of retinyl propionate was used as a control group. After 30 days of monitoring, the samples were retrieved and tested using a high-performance liquid chromatography-diode array detector to calculate the retention rate of retinyl propionate. The results are shown in Figure 8. In Figure 8, H1-Ret represents Example 1; H1&Lɑ-Ret represents Example 4; and Control represents the control group.

[0101] As shown in Figure 8, at 4°C, retinyl propionate showed virtually no degradation, with little difference between the hexagonal phase and the mixed-phase loaded retinyl propionate and free retinyl propionate. With increasing temperature, the retention rate of hexagonal phase-loaded retinyl propionate was significantly higher than that of the mixed-phase loaded retinyl propionate and free retinyl propionate. This indicates that the retinyl propionate was encapsulated within the hexagonal phase, surrounded by a dense surfactant layer of liquid crystal, thus isolating it from reactive oxygen species generated in the aqueous phase. Further increasing the temperature to 50°C, the retention rates of hexagonal phase, mixed-phase loaded retinyl propionate, and free retinyl propionate were all low. This is because at excessively high temperatures, the liquid crystal structure disappears, releasing the retinyl propionate. Reactive oxygen species in the aqueous phase then come into direct contact with the retinyl propionate, resulting in a similar degradation rate across the three phases. Therefore, within the range of human body temperature, the hexagonal phase liquid crystal sample obtained in Example 1 exhibits a significant performance advantage in terms of the stability of retinyl propionate activity.

[0102] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A liquid crystal emulsion containing sodium alkyl glycoside hydroxypropyl sulfonate, characterized in that, The liquid crystal emulsion comprises the following raw materials: sodium alkyl glycoside hydroxypropyl sulfonate solution and an oil phase; the oil phase is selected from at least one of dodecanoic acid and hexadecanoic acid; the mass concentration of the sodium alkyl glycoside hydroxypropyl sulfonate solution is 13-16%; the sodium alkyl glycoside hydroxypropyl sulfonate is lauryl glucoside hydroxypropyl sulfonate; the mass ratio of the sodium alkyl glycoside hydroxypropyl sulfonate solution to the oil phase is 100:5-7.

2. The liquid crystal emulsion according to claim 1, characterized in that, The mass concentration of the alkyl glycoside hydroxypropyl sulfonate sodium solution is 14-15%.

3. The liquid crystal emulsion according to claim 1, characterized in that, The oil phase is dodecanoic acid.

4. The liquid crystal emulsion according to claim 1, characterized in that, The mass ratio of the alkyl glycoside hydroxypropyl sulfonate sodium solution to the oil phase is 100:6-7.

5. A method for preparing the liquid crystal emulsion according to any one of claims 1-4, characterized in that, The preparation method is as follows: S1: Heat the oil phase to a molten state; S2: Prepare a sodium alkyl glycoside hydroxypropyl sulfonate solution; S3: After preheating the sodium alkyl glycoside hydroxypropyl sulfonate solution prepared in step S2, add it to the oil phase prepared in step S1 and stir for the first time. After homogenization, stir again and cool to room temperature to obtain a liquid crystal emulsion.

6. The preparation method according to claim 5, characterized in that, In step S1, the heating temperature is 60-80℃.

7. The preparation method according to claim 5, characterized in that, In step S2, the sodium alkyl glycoside hydroxypropyl sulfonate solution is obtained by dissolving sodium alkyl glycoside hydroxypropyl sulfonate in water.

8. The preparation method according to claim 5, characterized in that, In step S3, the preheating temperature is 75-85℃; the temperature of the first stirring is 75-85℃; the time is 3-5 min; and the speed is 350-450 r / min.

9. The preparation method according to claim 5, characterized in that, In step S3, the preheating temperature is 80°C.

10. The preparation method according to claim 5, characterized in that, In step S3, the temperature of the first stirring is 80℃; the time is 3 minutes; and the speed is 400 r / min.

11. The preparation method according to claim 5, characterized in that, In step S3, the homogenization speed is 10000-12000 r / min and the time is 1-2 min.

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