Hydroxypropyl chitosan-based embedding essential oil-phytosterol compound emulsion, and preparation method and application thereof

Abstract

This invention relates to the field of veterinary drug formulation and new feed additive technology, and proposes a compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil-phytosterols, its preparation method, and its application. The compound emulsion is composed of the following raw materials in weight percentages: 10%–15% hydroxypropyl chitosan essential oil-encapsulated emulsion, 6%–9% phytosterol liposome dispersion, 6%–10% medium-chain triglycerides, 1.5%–2.5% beeswax, 2%–3% hydrogenated soybean lecithin, 3%–4% polysorbate 80, 0.3%–0.5% xanthan gum, 5%–7% glycerol, 3%–5% glucose, 0.05%–0.1% potassium sorbate, 0.005%–0.008% antioxidant, and the balance being water. This technical solution solves the problem of poor treatment efficacy for bacterial diseases in calves in related technologies.

Description

Technical Field

[0001] This invention relates to the field of veterinary drug formulations and new feed additives, specifically to a compound emulsion of essential oil and phytosterols encapsulated with hydroxypropyl chitosan, its preparation method, and its application. Background Technology

[0002] The calf stage is a critical developmental period in cattle farming. Their immune systems are not yet fully developed, making them highly susceptible to passive immunization failure, which can lead to decreased resistance and common diseases such as bacterial diarrhea and respiratory illnesses. This severely impacts calf growth and development, causing significant economic losses to the livestock industry. Currently, traditional prevention and treatment of these bacterial diseases in calves mainly rely on antibiotics. However, long-term, inappropriate use of antibiotics can lead to antibiotic resistance in bacteria, reducing treatment effectiveness. Furthermore, antibiotic residues can affect the quality and safety of livestock products.

[0003] Therefore, there is an urgent need to develop a safe and efficient alternative prevention and treatment technology to improve diarrhea and respiratory diseases in calves and promote their growth and development. Summary of the Invention

[0004] This invention proposes a compound emulsion of essential oil and phytosterols based on hydroxypropyl chitosan encapsulation, its preparation method and application, which solves the problem of poor treatment effect of bacterial diseases in calves in related technologies.

[0005] The technical solution of the present invention is as follows: The present invention proposes a compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil and phytosterols. The compound emulsion is composed of the following raw materials in weight percentage: 10%~15% hydroxypropyl chitosan essential oil-encapsulated emulsion, 6%~9% phytosterol liposome dispersion, 6%~10% medium-chain triglycerides, 1.5%~2.5% beeswax, 2%~3% hydrogenated soybean lecithin, 3%~4% polysorbate 80, 0.3%~0.5% xanthan gum, 5%~7% glycerol, 3%~5% glucose, 0.05%~0.1% potassium sorbate, 0.005%~0.008% antioxidant, and the balance being water.

[0006] As a further technical solution, the hydroxypropyl chitosan essential oil encapsulation emulsion is composed of the following raw materials in weight percentage: 7%~9% hydroxypropyl chitosan, 9%~10% oregano oil, 6%~7% thyme oil, 3%~5% eucalyptus oil, 1%~2% polysorbate 80, and the balance being water.

[0007] As a further technical solution, the preparation method of the hydroxypropyl chitosan essential oil encapsulation emulsion includes the following steps: dissolving hydroxypropyl chitosan in 70% water to obtain an aqueous phase; mixing the oregano oil, thyme oil, eucalyptus oil, and polysorbate to obtain an oil phase; dripping the oil phase into the aqueous phase; shearing and adding the remaining water to obtain the hydroxypropyl chitosan essential oil encapsulation emulsion.

[0008] As a further technical solution, the shearing speed is 10000~12000rpm, preferably 12000rpm, and the shearing time is 10~20min, preferably 15min.

[0009] This invention relates to a hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion. While essential oils (such as oregano oil and thyme oil) possess natural antibacterial activity, their high volatility, pungent odor, and poor water solubility limit their application. Conventional β-cyclodextrin inclusion technology addresses these issues, but this technology is limited in function, only masking and stabilizing flavors without improving the in vivo metabolism of essential oils, and is a conventional technique in this field. This invention, by encapsulating essential oils with hydroxypropyl chitosan, effectively solves these problems, leveraging the sustained-release effect of the encapsulated essential oils, improving bioavailability, masking the odor of the essential oils, and enhancing the palatability and stability of the compound emulsion.

[0010] As a further technical solution, the preparation method of the phytosterol liposome dispersion includes the following steps: dissolving phytosterol and hydrogenated soybean lecithin in anhydrous ethanol, stirring evenly at 40°C to obtain an organic phase, dissolving polyvinylpyrrolidone in water to obtain an aqueous phase, adding the organic phase to the aqueous phase, stirring to obtain a primary emulsion, homogenizing the primary emulsion under high pressure, rotary evaporating, adding water, and then obtaining the phytosterol liposome dispersion.

[0011] As a further technical solution, the mass-to-volume ratio of the phytosterol, the hydrogenated soybean lecithin, and the anhydrous ethanol is 18~22g:22~28g:140~160mL, the mass ratio of the polyvinylpyrrolidone and the water is 0.8~1.2:30, and the mass ratio of the added water to the phytosterol is 1:1~1.1.

[0012] As a further technical solution, the mass ratio of the phytosterol to the polyvinylpyrrolidone is 20:1.

[0013] As a further technical solution, the stirring time is 30 minutes.

[0014] As a further technical solution, the pressure of the high-pressure homogenization is 900 bar, and the number of high-pressure homogenization cycles is 6.

[0015] As a further technical solution, the temperature of the rotary evaporation is 40°C.

[0016] As a further technical solution, the hydroxypropyl chitosan is composed of a first hydroxypropyl chitosan and a second hydroxypropyl chitosan, wherein the first hydroxypropyl chitosan and the second hydroxypropyl chitosan have different degrees of deacetylation.

[0017] As a further technical solution, the degree of deacetylation of the first hydroxypropyl chitosan is 80%, the degree of deacetylation of the second hydroxypropyl chitosan is 90%, and the mass ratio of the first hydroxypropyl chitosan to the second hydroxypropyl chitosan is 1:1~2.

[0018] This invention is based on hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsions. The hydroxypropyl chitosan is composed of first and second hydroxypropyl chitosans with different degrees of deacetylation. The first hydroxypropyl chitosan, with its 80% degree of deacetylation, has a relatively loose molecular structure, resulting in good dispersion and solubility in solvents. This provides a basis for the uniform mixing of the compound emulsion, ensuring that each component can fully contact and be uniformly dispersed in the system during preparation, forming a uniform and stable emulsion. The second hydroxypropyl chitosan, with a deacetylation degree of 90%, has stronger intermolecular forces, resulting in a more compact and stable structure. During emulsion storage, it can resist the influence of external environmental factors (such as temperature changes), preventing component separation and deterioration. The synergy of the two further ensures the stability of the compound emulsion.

[0019] This invention also proposes a method for preparing a hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion, which includes the following steps: S1. Dissolve the potassium sorbate and glucose in water to obtain an aqueous phase. Grind the xanthan gum and 35% glycerol evenly and add them to the aqueous phase to disperse evenly. Add the remaining glycerol, the antioxidant, the hydroxypropyl chitosan essential oil encapsulation emulsion and the phytosterol liposome dispersion, and stir evenly to obtain a composite aqueous phase. S2. The medium-chain triglycerides, beeswax, hydrogenated soybean lecithin, and polysorbate 80 are heated and melted to obtain an oil phase; S3. Heat the composite aqueous phase to 70°C, add the oil phase to the composite aqueous phase, homogenize, stir and cool to 30°C, degas under vacuum, and fill to obtain the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion.

[0020] As a further technical solution, in step S1, the stirring speed is 800 rpm and the stirring time is 10 min.

[0021] As a further technical solution, in step S2, the heating and melting temperature is 75°C.

[0022] As a further technical solution, in step S3, the homogenization speed is 3500 rpm and the homogenization time is 12 min.

[0023] As a further technical solution, the antioxidant is butylated hydroxytoluene.

[0024] This invention is based on a hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion. The phytosterol liposome dispersion contains phytosterols as a raw material. Phytosterols possess excellent anti-inflammatory and immunomodulatory functions, enhancing the immunity of calves and aiding in resistance to pathogen infection. However, phytosterols are highly hydrophobic, making them difficult to absorb orally and resulting in extremely low bioavailability. Although some studies have used nanoliposome technology to improve their solubility, combining nano-phytosterol liposomes with plant essential oils presents a serious challenge to formulation stability. Both are hydrophobic components, easily leading to phase separation in the emulsion matrix, resulting in oil phase precipitation and emulsion demulsification, preventing the formation of a stable compound formulation. This invention utilizes a combination of hydrogenated soybean lecithin and polysorbate 80 to construct a stable oil-water interface. Combined with a xanthan gum three-dimensional gel network, hydroxypropyl chitosan-encapsulated essential oil and phytosterol liposomes are stably dispersed in the emulsion matrix, solving the stability problem of highly hydrophobic compound formulations.

[0025] This invention also proposes the application of a hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion, prepared by the aforementioned method, in the fields of calf diarrhea, respiratory diseases, and growth and development.

[0026] The working principle and beneficial effects of this invention are as follows: 1. This invention is based on the addition of hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion to hydroxypropyl chitosan-encapsulated essential oil microspheres. The encapsulation of hydroxypropyl chitosan effectively masks the irritating odor of the essential oil, and its film-forming properties provide additional physical stability to the emulsion system, ensuring the palatability and shelf life of the product. Furthermore, the hydroxypropyl chitosan-encapsulated essential oil microspheres can slowly release the essential oil in the digestive tract of calves, significantly prolonging the duration of action, overcoming the disadvantages of rapid metabolism of essential oils and the need for frequent administration, and greatly improving bioavailability.

[0027] 2. Based on the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion, the hydroxypropyl chitosan, essential oil and phytosterol work synergistically to produce a triple synergistic effect of antibacterial-anti-inflammatory-immunomodulatory, effectively improving the therapeutic effect of the compound emulsion.

[0028] 3. This invention is based on hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion. The ingredients are all-natural plant-derived, with no drug resistance or residues. It can replace antibiotics for daily prevention and is in line with the trend of green farming. Attached Figure Description

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] Figure 1 This is a line graph showing the cumulative release rate of the compound emulsion in Example 1 of the present invention over time. Figure 2 This is a line graph showing the cumulative release rate of the compound emulsion in Comparative Example 3 of the present invention over time. Figure 3 This is a photograph of the compound emulsion from Example 1 of the present invention, taken as an example for stability observation. Figure 4 These are physical images of the stability observation of the compound emulsions of Comparative Examples 1 to 3 of the present invention. From left to right, they are Comparative Example 1, Comparative Example 2, and Comparative Example 3. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] In the following examples and comparative examples: First-hydroxypropyl chitosan: Degree of deacetylation is 80%; Second hydroxypropyl chitosan: Degree of deacetylation is 90%; Polyvinylpyrrolidone: Model number K30.

[0033] Example 1 The hydroxypropyl chitosan essential oil encapsulation emulsion is composed of the following raw materials by weight percentage: 8% hydroxypropyl chitosan, 9.6% oregano oil, 6.4% thyme oil, 4% eucalyptus oil, 1.6% polysorbate 80, and the balance being water; The preparation method of hydroxypropyl chitosan essential oil encapsulation emulsion includes the following steps: dissolving hydroxypropyl chitosan in 70% water to obtain an aqueous phase; mixing oregano oil, thyme oil, eucalyptus oil and polysorbate to obtain an oil phase; dripping the oil phase into the aqueous phase; shearing at 12000 rpm for 15 min; and then adding the remaining water to obtain the hydroxypropyl chitosan essential oil encapsulation emulsion. The preparation method of phytosterol liposome dispersion includes the following steps: phytosterol and hydrogenated soybean lecithin are dissolved in anhydrous ethanol and stirred evenly at 40°C to obtain an organic phase; polyvinylpyrrolidone is dissolved in water to obtain an aqueous phase; the organic phase is added to the aqueous phase and stirred for 30 min to obtain a primary emulsion; the primary emulsion is homogenized under high pressure at 900 bar 6 times and rotary evaporated at 40°C to remove ethanol; after adding water, phytosterol liposome dispersion is obtained. The mass-to-volume ratio of phytosterols, hydrogenated soybean lecithin, and anhydrous ethanol was 20g:25g:150mL. The mass ratio of polyvinylpyrrolidone to water is 1:30; The mass ratio of phytosterols to polyvinylpyrrolidone is 20:1; A compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil and phytosterols, the compound emulsion being composed of the following raw materials in weight percentage: 10% hydroxypropyl chitosan essential oil-encapsulated emulsion, 6% phytosterol liposome dispersion, 6% medium-chain triglycerides, 1.5% beeswax, 2% hydrogenated soybean lecithin, 3% polysorbate 80, 0.3% xanthan gum, 5% glycerol, 3% glucose, 0.05% potassium sorbate, 0.005% butylated hydroxytoluene, with the balance being water; A method for preparing an essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation includes the following steps: S1. Dissolve potassium sorbate and glucose in water to obtain an aqueous phase. Grind xanthan gum and 35% glycerol evenly and add them to the aqueous phase to disperse evenly. Add the remaining glycerol, butylated hydroxytoluene, hydroxypropyl chitosan essential oil embedding emulsion and phytosterol liposome dispersion, and stir evenly to obtain a composite aqueous phase. S2. Medium-chain triglycerides, beeswax, hydrogenated soybean lecithin and polysorbate 80 are heated to 75°C to melt and obtain the oil phase; S3. Heat the composite aqueous phase to 70°C, add the oil phase to the composite aqueous phase, homogenize at 3500 rpm for 12 min, stir and cool to 30°C, degas under vacuum and fill to obtain a compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil-phytosterol. Figure 1 This is a line graph showing the cumulative release rate of the compound emulsion in this embodiment over time. Figure 3 This is a photograph of the compound emulsion used in this embodiment to observe its stability.

[0034] Example 2 The hydroxypropyl chitosan essential oil encapsulation emulsion is composed of the following raw materials by weight percentage: 8% hydroxypropyl chitosan, 9.6% oregano oil, 6.4% thyme oil, 4% eucalyptus oil, 1.6% polysorbate 80, and the balance being water; The preparation method of hydroxypropyl chitosan essential oil encapsulation emulsion includes the following steps: dissolving hydroxypropyl chitosan in 70% water to obtain an aqueous phase; mixing oregano oil, thyme oil, eucalyptus oil and polysorbate to obtain an oil phase; dripping the oil phase into the aqueous phase; shearing at 12000 rpm for 15 min; and then adding the remaining water to obtain the hydroxypropyl chitosan essential oil encapsulation emulsion. The preparation method of phytosterol liposome dispersion includes the following steps: phytosterol and hydrogenated soybean lecithin are dissolved in anhydrous ethanol and stirred evenly at 40°C to obtain an organic phase; polyvinylpyrrolidone is dissolved in water to obtain an aqueous phase; the organic phase is added to the aqueous phase and stirred for 30 min to obtain a primary emulsion; the primary emulsion is homogenized under high pressure at 900 bar 6 times and rotary evaporated at 40°C to remove ethanol; after adding water, phytosterol liposome dispersion is obtained. The mass-to-volume ratio of phytosterols, hydrogenated soybean lecithin, and anhydrous ethanol was 20g:25g:150mL. The mass ratio of polyvinylpyrrolidone to water is 1:30; The mass ratio of phytosterols to polyvinylpyrrolidone is 20:1; A compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil and phytosterols, the compound emulsion being composed of the following raw materials in weight percentage: 12.5% ​​hydroxypropyl chitosan essential oil-encapsulated emulsion, 7.5% phytosterol liposome dispersion, 8% medium-chain triglycerides, 2% beeswax, 2.5% hydrogenated soybean lecithin, 3% polysorbate 80, 0.4% xanthan gum, 6% glycerol, 4% glucose, 0.1% potassium sorbate, 0.005% butylated hydroxytoluene, with the balance being water; A method for preparing an essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation includes the following steps: S1. Dissolve potassium sorbate and glucose in water to obtain an aqueous phase. Grind xanthan gum and 35% glycerol evenly and add them to the aqueous phase to disperse evenly. Add the remaining glycerol, butylated hydroxytoluene, hydroxypropyl chitosan essential oil embedding emulsion and phytosterol liposome dispersion, and stir evenly to obtain a composite aqueous phase. S2. Medium-chain triglycerides, beeswax, hydrogenated soybean lecithin and polysorbate 80 are heated to 75°C to melt and obtain the oil phase; S3. Heat the composite aqueous phase to 70°C, add the oil phase to the composite aqueous phase, homogenize at 3500 rpm for 12 min, stir and cool to 30°C, degas under vacuum, and fill to obtain a compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil-phytosterol.

[0035] Example 3 The hydroxypropyl chitosan essential oil encapsulation emulsion is composed of the following raw materials by weight percentage: 8% hydroxypropyl chitosan, 9.6% oregano oil, 6.4% thyme oil, 4% eucalyptus oil, 1.6% polysorbate 80, and the balance being water; The preparation method of hydroxypropyl chitosan essential oil encapsulation emulsion includes the following steps: dissolving hydroxypropyl chitosan in 70% water to obtain an aqueous phase; mixing oregano oil, thyme oil, eucalyptus oil and polysorbate to obtain an oil phase; dripping the oil phase into the aqueous phase; shearing at 12000 rpm for 15 min; and then adding the remaining water to obtain the hydroxypropyl chitosan essential oil encapsulation emulsion. The preparation method of phytosterol liposome dispersion includes the following steps: phytosterol and hydrogenated soybean lecithin are dissolved in anhydrous ethanol and stirred evenly at 40°C to obtain an organic phase; polyvinylpyrrolidone is dissolved in water to obtain an aqueous phase; the organic phase is added to the aqueous phase and stirred for 30 min to obtain a primary emulsion; the primary emulsion is homogenized under high pressure at 900 bar 6 times and rotary evaporated at 40°C to remove ethanol; after adding water, phytosterol liposome dispersion is obtained. The mass-to-volume ratio of phytosterols, hydrogenated soybean lecithin, and anhydrous ethanol was 20g:25g:150mL. The mass ratio of polyvinylpyrrolidone to water is 1:30; The mass ratio of phytosterols to polyvinylpyrrolidone is 20:1; A compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil and phytosterols, the compound emulsion being composed of the following raw materials in weight percentage: 15% hydroxypropyl chitosan essential oil-encapsulated emulsion, 9% phytosterol liposome dispersion, 10% medium-chain triglycerides, 2.5% beeswax, 3% hydrogenated soybean lecithin, 4% polysorbate 80, 0.5% xanthan gum, 7% glycerol, 5% glucose, 0.1% potassium sorbate, 0.008% butylated hydroxytoluene, with the balance being water; A method for preparing an essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation includes the following steps: S1. Dissolve potassium sorbate and glucose in water to obtain an aqueous phase. Grind xanthan gum and 35% glycerol evenly and add them to the aqueous phase to disperse evenly. Add the remaining glycerol, butylated hydroxytoluene, hydroxypropyl chitosan essential oil embedding emulsion and phytosterol liposome dispersion, and stir evenly to obtain a composite aqueous phase. S2. Medium-chain triglycerides, beeswax, hydrogenated soybean lecithin and polysorbate 80 are heated to 75°C to melt and obtain the oil phase; S3. Heat the composite aqueous phase to 70°C, add the oil phase to the composite aqueous phase, homogenize at 3500 rpm for 12 min, stir and cool to 30°C, degas under vacuum, and fill to obtain a compound emulsion based on hydroxypropyl chitosan-encapsulated essential oil-phytosterol.

[0036] Example 4 The difference between Example 4 and Example 2 is that the hydroxypropyl chitosan is a second hydroxypropyl chitosan.

[0037] Example 5 The difference between Example 5 and Example 2 is that the hydroxypropyl chitosan is composed of a first hydroxypropyl chitosan and a second hydroxypropyl chitosan in a mass ratio of 1:1.

[0038] Example 6 The difference between Example 6 and Example 2 is that the hydroxypropyl chitosan is composed of a first hydroxypropyl chitosan and a second hydroxypropyl chitosan in a mass ratio of 1:2.

[0039] Comparative Example 1 Compared with Example 2, Comparative Example 1 differs in that the raw materials of the compound emulsion do not contain hydrogenated soybean lecithin.

[0040] Comparative Example 2 Compared with Example 2, Comparative Example 2 differs in that the raw materials of the compound emulsion do not contain polysorbate 80.

[0041] Comparative Example 3 Compared with Example 2, the difference of Comparative Example 3 is that the raw materials of the hydroxypropyl chitosan essential oil encapsulation emulsion do not contain hydroxypropyl chitosan. Figure 2 Line graph showing the cumulative release rate of this comparative compound emulsion over time; Figure 4 The images show the stability observations of the compound emulsions in Comparative Examples 1-3, from left to right: Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0042] Experimental Example 1 The compound emulsions prepared in Examples 1-6 and Comparative Examples 1-3 were placed at 40°C and 75% relative humidity, and their appearance, centrifugal stability, particle size, and retention rate of 1,8-cineole in eucalyptus oil were tested at 0d, 3d, 30d, and 90d, respectively.

[0043] The test results are shown in Table 1: Table 1 Performance test results of Examples 1-6 and Comparative Examples 1-3

[0044] Table 1 shows that the compound emulsions prepared in Examples 1-6 showed no phase separation, indicating that the emulsions prepared by this invention are stable and can be stored stably for a long time. When the hydroxypropyl chitosan is composed of first and second hydroxypropyl chitosans with different degrees of deacetylation, the stability of the composite emulsion is even better. Comparing Comparative Examples 1-2 with the Examples, the synergistic effect of hydrogenated soybean lecithin and polysorbate 80 is key to stability. Comparative Example 3 did not use hydroxypropyl chitosan encapsulation, and its stability was lower than that of the Examples, demonstrating that hydroxypropyl chitosan encapsulation makes a significant contribution to the stability of the system.

[0045] Experimental Example 2 The compound emulsions prepared in Example 2 and Comparative Examples 1-3 were tested. Sixty newborn Holstein calves were randomly divided into four groups. Each group was given 10g of the compound emulsion per 10kg of body weight daily. The calves were fed the compound emulsions prepared in Example 2 and Comparative Examples 1-3 once a day for seven consecutive days. During the experiment, diarrhea, weight gain, and other symptoms were observed and recorded. Blood samples were collected for testing at the end of the experiment.

[0046] The test results are shown in Table 2: Table 2 Performance test results of Example 2 and Comparative Examples 1-3

[0047] As shown in Table 2, the composite emulsion prepared in Example 2 is significantly superior to other comparative examples in reducing diarrhea, promoting growth, and inhibiting inflammation. This indicates that the composite emulsion prepared by the present invention has good application effects in preventing and treating diarrhea and respiratory diseases in calves and promoting their growth and development. The present invention successfully solves the technical problems of rapid essential oil volatilization, poor absorption of phytosterols, and unstable compounding by using hydroxypropyl chitosan encapsulation, hydrogenated soybean lecithin, and polysorbate 80, providing a highly efficient, stable, and sustained-release composite emulsion.

[0048] Example 3 Using 1,8-cineole in eucalyptus oil as an indicator, the composite emulsions prepared in Example 1 and Comparative Example 3, containing equal amounts of 1,8-cineole (5.0 mg), were accurately weighed using the dialysis bag method and placed in a dialysis bag. A release test was conducted in 900 mL of PBS at pH 6.8 (37°C, 50 rpm). Samples were taken at 0.5 h, 1 h, 2 h, 4 h, 6 h, 8 h, 12 h, and 24 h, and the cumulative release rate (%, n=3) was determined by HPLC.

[0049] Table 3. In vitro cumulative release rate performance test results of Example 2 and Comparative Example 3

[0050] As shown in Table 3, the 1,8-cineole release process of the composite emulsion prepared in Example 2 was gradual, with a T50% of 4.2 h. In contrast, the release rate of Comparative Example 3 exceeded 65% within 1 h, with a T50% of only 0.8 h, demonstrating that hydroxypropyl chitosan encapsulation can significantly delay the release of essential oils.

[0051] Experiment Example 4 The agar diffusion method was used, with *Escherichia coli* as the indicator bacterium. In vitro antibacterial tests were performed on Example 2, Comparative Examples 1-3, the PBS negative control, and the 0.1% ampicillin positive control, and the diameter of the inhibition zone (mm, n=3) was measured.

[0052] Table 4 Performance test results of Example 2 and Comparative Examples 1-3

[0053] As shown in Table 4, Example 2 produced the largest inhibition zone, indicating that the hydroxypropyl chitosan encapsulation maintained the local effective concentration through sustained release, and that the combination of phytosterols and essential oils produced a synergistic antibacterial effect.

[0054] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A compound emulsion of essential oils and phytosterols based on hydroxypropyl chitosan encapsulation, characterized in that, The compound emulsion is composed of the following raw materials in weight percentage: 10%~15% hydroxypropyl chitosan essential oil encapsulation emulsion, 6%~9% phytosterol liposome dispersion, 6%~10% medium-chain triglycerides, 1.5%~2.5% beeswax, 2%~3% hydrogenated soybean lecithin, 3%~4% polysorbate 80, 0.3%~0.5% xanthan gum, 5%~7% glycerol, 3%~5% glucose, 0.05%~0.1% potassium sorbate, 0.005%~0.008% antioxidant, and the balance being water.

2. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 1, characterized in that, The hydroxypropyl chitosan essential oil encapsulation emulsion is composed of the following raw materials in weight percentage: 7%~9% hydroxypropyl chitosan, 9%~10% oregano oil, 6%~7% thyme oil, 3%~5% eucalyptus oil, 1%~2% polysorbate, and the balance being water.

3. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 2, characterized in that, The preparation method of the hydroxypropyl chitosan essential oil encapsulation emulsion includes the following steps: dissolving hydroxypropyl chitosan in 70% water to obtain an aqueous phase; mixing the oregano oil, thyme oil, eucalyptus oil, and polysorbate to obtain an oil phase; dripping the oil phase into the aqueous phase; shearing and adding the remaining water to obtain the hydroxypropyl chitosan essential oil encapsulation emulsion.

4. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 3, characterized in that, The shearing speed is 10,000 to 12,000 rpm, and the shearing time is 10 to 20 minutes.

5. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 1, characterized in that, The preparation method of the phytosterol liposome dispersion includes the following steps: dissolving phytosterol and hydrogenated soybean lecithin in anhydrous ethanol, stirring at 40°C to obtain an organic phase, dissolving polyvinylpyrrolidone in water to obtain an aqueous phase, adding the organic phase to the aqueous phase, stirring to obtain a primary emulsion, homogenizing the primary emulsion under high pressure, rotary evaporating, adding water to obtain the phytosterol liposome dispersion.

6. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 5, characterized in that, The mass-to-volume ratio of the phytosterol, the hydrogenated soybean lecithin, and the anhydrous ethanol is 18-22 g: 22-28 g: 140-160 mL, the mass ratio of the polyvinylpyrrolidone and the water is 0.8-1.2:30, and the mass ratio of the added water to the phytosterol is 1:1-1.

1.

7. The essential oil-phytosterol compound emulsion based on hydroxypropyl chitosan encapsulation according to claim 2, characterized in that, The hydroxypropyl chitosan is composed of a first hydroxypropyl chitosan and a second hydroxypropyl chitosan, and the first hydroxypropyl chitosan and the second hydroxypropyl chitosan have different degrees of deacetylation.

8. A compound emulsion of essential oil and phytosterols based on hydroxypropyl chitosan encapsulation according to claim 7, characterized in that, The degree of deacetylation of the first hydroxypropyl chitosan is 80%, the degree of deacetylation of the second hydroxypropyl chitosan is 90%, and the mass ratio of the first hydroxypropyl chitosan to the second hydroxypropyl chitosan is 1:1~2.

9. A method for preparing a hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion, used to prepare the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Dissolve the potassium sorbate and glucose in water to obtain an aqueous phase. Grind the xanthan gum and 35% glycerol evenly and add them to the aqueous phase to disperse evenly. Add the remaining glycerol, the antioxidant, the hydroxypropyl chitosan essential oil encapsulation emulsion and the phytosterol liposome dispersion, and stir evenly to obtain a composite aqueous phase. S2. The medium-chain triglycerides, beeswax, hydrogenated soybean lecithin, and polysorbate 80 are heated and melted to obtain an oil phase; S3. Heat the composite aqueous phase to 70°C, add the oil phase to the composite aqueous phase, homogenize, stir and cool to 30°C, degas under vacuum, and fill to obtain the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion.

10. The application of the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion prepared according to any one of claims 1 to 8 or the preparation method of the hydroxypropyl chitosan-encapsulated essential oil-phytosterol compound emulsion according to claim 9 in the fields of calf diarrhea, respiratory diseases, and promotion of calf growth and development.

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