Dry eye drops

Abstract

The present application relates to a kind of dry eye drops, it includes by mass percentage: chondroitin sulfate 0.1%-0.5%, silk fibroin nanoparticles containing astaxanthin 0.06%-0.3%, sodium hyaluronate 0.1%-0.3%, vitamin E 0.05%-0.1%, sodium chloride 0.9-1.0%, poloxamer 0.05%-0.1%, EDTA 0.01%-0.1%, phosphate buffer and the balance of water;Wherein, the silk fibroin nanoparticles containing astaxanthin particle size is 50-300nm;Phosphate buffer is adjusted to 6.8-7.9 to the pH of eye drop.The eye drop of the present application can effectively relieve dry eye symptoms, provide long time wet and protection, while reducing eye inflammation and oxidative stress, significantly improve dry eye, and high use safety.

Description

Technical Field

[0001] This invention relates to the field of ophthalmic drug technology, specifically to an eye drop for dry eye syndrome. Background Technology

[0002] Dry eye syndrome is a condition that causes symptoms such as eye discomfort and visual dysfunction. It is related to abnormalities in the quantity or quality of tears and can cause damage to the surface of the eye, such as the cornea. Abnormalities in tear quantity primarily refer to a state of low tear secretion, which is an indicator of dry eye syndrome based on tear volume. Regarding tear quality, abnormalities in tear composition (such as low lipid or protein content in tears) can deteriorate the stability of the tear film, leading to dryness of the eye surface even with tear secretion.

[0003] Astaxanthin is known to be a potent natural antioxidant with various biological activities, including antioxidant, anti-inflammatory, immunomodulatory, and photoprotective effects. Using astaxanthin in eye drops could potentially provide therapeutic or preventative effects against a variety of eye problems. Several patent applications have already incorporated astaxanthin as an active ingredient in eye drops. For example, CN107106627A discloses an eye drop dispenser and an antioxidant eye drop composition, which mainly includes antioxidant components such as green tea extract, resveratrol, and astaxanthin. CN117752597A discloses an eye drop for relieving dry eye syndrome, containing sorbitol, resveratrol, modified chitosan, Potentilla fruticosa extract, dandelion extract, EDTA, astaxanthin, vitamin A, dextran, and hyaluronic acid. Although astaxanthin possesses antioxidant, anti-inflammatory, immunomodulatory, and photoprotective properties...

[0004] While astaxanthin has proven its efficacy, several challenges remain in its production as eye drops: ① Solubility: Astaxanthin has poor solubility in water, requiring the use of appropriate solvents or carriers to improve its solubility and bioavailability. ② Stability: Astaxanthin is easily degraded under light, high temperature, and oxidative conditions. Ensuring the stability of astaxanthin in eye drops, especially during production sterilization, storage, and transportation, is a problem that needs to be solved. Furthermore, the safety of the eye drops is also an issue that urgently needs improvement. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an eye drop for dry eye syndrome, which uses sericin to encapsulate astaxanthin. By utilizing the high hydrophilicity and film-forming properties of sericin, the stability and bioavailability of astaxanthin can be improved. At the same time, sericin also has moisturizing, antioxidant and antibacterial properties, which help to improve dry eye syndrome. It solves the technical problem of poor solubility and stability when directly adding astaxanthin to eye drops.

[0007] (II) Technical Solution

[0008] This invention provides an eye drop for dry eye, comprising, by mass percentage: 0.1%-0.5% chondroitin sulfate, 0.06%-0.3% sericin nanoparticles containing astaxanthin, 0.1%-0.3% sodium hyaluronate, 0.05%-0.1% vitamin E, 0.9%-1.0% sodium chloride, 0.05%-0.1% poloxamer, 0.01%-0.1% EDTA, phosphate buffer, and the balance being water; wherein the astaxanthin-containing sericin nanoparticles have a particle size of 50-300 nm; the phosphate buffer adjusts the pH of the eye drop to 6.8-7.9.

[0009] According to a preferred embodiment of the present invention, the dry eye eye drops are composed of: 0.1% chondroitin sulfate, 0.1% sericin nanoparticles containing astaxanthin, 0.2% sodium hyaluronate, 0.05% vitamin E, 0.9% sodium chloride, 0.075% poloxamer, 0.05% EDTA, phosphate buffer, and the balance being water; the pH of the eye drops is 7.4.

[0010] According to a preferred embodiment of the present invention, the dry eye eye drops do not contain preservatives.

[0011] Secondly, the present invention provides a method for preparing an eye drop for dry eye syndrome, comprising:

[0012] S1. Preparation of sericin nanoparticles containing astaxanthin

[0013] The first solution is prepared by dissolving sericin in water or phosphate buffer, and the second solution is prepared by dissolving astaxanthin in anhydrous ethanol or 95% ethanol. The second solution is added to the first solution and the mixture is subjected to high-speed stirring or ultrasonic treatment to form a stable emulsion. The emulsion is then cooled to 2-8°C, centrifuged, and the precipitate is separated and freeze-dried to obtain sericin nanoparticles containing astaxanthin.

[0014] S2. Add sodium chloride, sodium hyaluronate, chondroitin sulfate, sericin nanoparticles containing astaxanthin, vitamin E, and poloxamer to sterile water. Stir well, then add phosphate buffer and stir well again. Adjust the pH to 6.8-7.9, filter through a 0.22μm filter membrane, and dispense the filtered solution into sterile eye drop bottles.

[0015] According to a preferred embodiment of the present invention, in S1, the concentration of sericin in the first solution is 1-5%; the preparation process of the first solution is as follows: sericin powder is added to water or phosphate buffer while stirring until completely dissolved, and the temperature is controlled at 25-45℃ during the dissolution process (appropriate heating can promote the dissolution of sericin in water). After dissolution, the solution is filtered through a 0.45μm filter membrane to obtain the first solution.

[0016] According to a preferred embodiment of the present invention, in S1, the concentration of astaxanthin in the second solution is 0.1-1%; the preparation process of the second solution is as follows: at room temperature, astaxanthin powder is added to anhydrous ethanol or 95% ethanol while stirring until it is completely dissolved, and after dissolution, it is filtered through a 0.45μm filter membrane to obtain the second solution.

[0017] According to a preferred embodiment of the present invention, in S1, the first solution and the second solution are prepared at a volume ratio of 5:1 to 1:1. The second solution is slowly added to the first solution while stirring at high speed (e.g., 1000-3000 rpm) for 10-30 minutes until a stable emulsion is formed. The temperature during the emulsification process does not exceed 25°C. The emulsion is quickly transferred to an ice bath or refrigerator and rapidly cooled to 4-8°C for 0.5-1 hour. It is then centrifuged at 10000-15000g for 10-20 minutes. After centrifugation, the precipitate is separated and freeze-dried to obtain sericin nanoparticles containing astaxanthin.

[0018] Preferably, the separated supernatant can be used to prepare the first solution after sterilization.

[0019] Preferably, after being dispensed into sterile eye drop bottles, the solution is sterilized by irradiation with 10-20 kGy gamma rays at 4-10°C before being stored. This sterilization condition achieves sterilization while minimizing the decomposition of antioxidant components in the eye drops.

[0020] (III) Beneficial Effects

[0021] The technical advantages of this invention are as follows:

[0022] (1) This invention uses sericin to coat astaxanthin. Utilizing the high hydrophilicity and film-forming properties of sericin, which has good solubility in water, the stability and bioavailability of astaxanthin can be improved. Simultaneously, sericin itself possesses moisturizing, viscosity-regulating, antioxidant, and antibacterial properties, which help improve dry eye syndrome. This solves the technical problem of poor solubility and stability associated with directly adding astaxanthin to eye drops. Furthermore, coating astaxanthin with sericin enables long-lasting sustained release, improving its bioavailability and anti-inflammatory and immunomodulatory effects. Sericin also acts as a natural preservative, significantly enhancing product safety.

[0023] (2) Experiments have shown that the eye drops of the present invention can effectively relieve dry eye symptoms, provide long-term hydration and protection, reduce eye inflammation and oxidative stress, and significantly improve dry eye syndrome. Attached Figure Description

[0024] Figure 1 This is a comparison image of corneal staining in mice before and after modeling with benzalkonium chloride (BAC).

[0025] Figure 2 Comparison of tear secretion in mice before and after modeling with benzalkonium chloride (BAC).

[0026] Figure 3 The levels of the corneal inflammatory factor IL-1β in mice were compared among the groups of mice 14 days after administration of the drug.

[0027] Figure 4 The curves showing the change in astaxanthin retention rate over storage time in eye drops of Example 3 and Comparative Examples 1-2 are shown. Detailed Implementation

[0028] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The eye drops of this invention contain chondroitin sulfate, astaxanthin-containing sericin nanoparticles, sodium hyaluronate, vitamin E, sodium chloride, poloxamer, EDTA, and other ingredients. Chondroitin sulfate has excellent moisturizing, anti-inflammatory, and corneal-protective effects. It can absorb and retain moisture, helping to maintain the hydration of the eye surface and reduce eye inflammation. Chondroitin sulfate helps protect the corneal epithelium, reducing damage to the cornea from external stimuli. It works synergistically with sodium hyaluronate to enhance the moisturizing effect. Astaxanthin is a powerful antioxidant that neutralizes free radicals, reducing oxidative stress damage to the eyes. It also has anti-inflammatory properties, reduces eye inflammation, protects the retina, and maintains visual health. Astaxanthin and vitamin E work synergistically to provide powerful antioxidant and anti-inflammatory effects, and together with chondroitin sulfate and sodium hyaluronate, they provide moisturizing and anti-inflammatory effects.

[0030] Sericin, acting as a carrier of astaxanthin, enhances the dispersibility and stability of astaxanthin in eye drops, providing sustained-release effects and improving its bioavailability. Sericin also possesses antibacterial properties; specifically, sericin (S1, S2) and small-molecule sericin peptide (S3) exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria. Sericin is non-toxic to cells and promotes cell growth with increasing concentration. Quantitative tests showed significant antibacterial activity against Staphylococcus aureus and Escherichia coli. Sericin exhibits good antibacterial properties and biocompatibility, making it a viable alternative to chemical preservatives and improving the safety of eye drops. The eye drops of this invention can be used without chemical preservatives. Furthermore, single-dose packaging avoids the use of preservatives, making it suitable for patients sensitive to preservatives.

[0031] Sodium hyaluronate has extremely strong moisturizing properties, providing long-lasting hydration. It helps lubricate the surface of the eyeball, reduces friction, and relieves dryness. It forms a protective film on the cornea, protecting the corneal epithelium from damage. It works synergistically with chondroitin sulfate to enhance moisturizing effects, and with astaxanthin and vitamin E to provide antioxidant and anti-inflammatory effects.

[0032] Sodium chloride adjusts the osmotic pressure to be similar to that of tears, reducing eye irritation. Poloxamer solubilizes and enhances the dispersibility and stability of drugs. EDTA chelates metal ions in the solution, preventing catalytic oxidation reactions caused by metal particles introduced into the eye drops during production by water or equipment, thus improving the stability of the eye drops. EDTA also enhances the stability of sericin, vitamin E, and other preservatives by chelating metal ions.

[0033] The eye drop formulation of this invention comprises components that work synergistically through the following mechanisms:

[0034] Enhanced stability and solubility: Astaxanthin is coated with sericin, which utilizes the high hydrophilicity and film-forming properties of sericin to reduce the chance of astaxanthin being oxidized, thereby improving the stability and solubility of astaxanthin in water, increasing bioavailability, and providing a long-lasting sustained-release effect; in addition, it can also enable the eye drops to be well preserved at room temperature, reducing the product's storage costs.

[0035] Moisturizing and lubricating: Chondroitin sulfate and sodium hyaluronate work together to provide powerful moisturizing and lubricating effects, reducing dryness.

[0036] Antioxidant and anti-inflammatory: Sericin, astaxanthin, vitamin E, and chondroitin sulfate work together to provide antioxidant and anti-inflammatory effects, protecting the eyes from oxidative stress and inflammation.

[0037] Preservative and stabilizing agents: Sericin and EDTA work together to provide preservative and stabilizing effects, ensuring the long-term stability and safety of the eye drops.

[0038] Osmotic pressure and pH adjustment: Sodium chloride and phosphate buffer work together to adjust the osmotic pressure and pH of the eye drops, making them suitable for ocular use.

[0039] Solubilization and Dispersion: Poloxamer improves the dispersibility and stability of lipid-soluble components, ensuring the uniformity and effectiveness of eye drops.

[0040] To verify the technical effects of the present invention, specific embodiments are described below. Unless otherwise specified in the following embodiments, % refers to mass concentration.

[0041] Example 1

[0042] This embodiment provides a method for preparing sericin nanoparticles containing astaxanthin:

[0043] (1) Add the sericin powder to the phosphate buffer while stirring until it is completely dissolved. Maintain the temperature at 35-38℃ during the dissolution process. After dissolution, filter through a 0.45μm filter membrane to obtain the first solution, in which the sericin concentration is 3%.

[0044] (2) At room temperature, add astaxanthin powder to 95% ethanol while stirring until completely dissolved. After dissolution, filter through a 0.45μm filter membrane to obtain a second solution with an astaxanthin concentration of 1%.

[0045] (3) Prepare the first solution and the second solution at a volume ratio of 1:1. Slowly add the second solution to the first solution while stirring at 3000 rpm. After the addition is complete, continue stirring for 10 min until a stable emulsion is formed. Treat the emulsion in a water bath and control the emulsification temperature to not exceed 25℃. Quickly transfer the emulsion to an ice bath and cool it rapidly to 4-8℃ for 1 h. Centrifuge at 10000g for 10 min. After centrifugation, separate the precipitate and freeze-dry the precipitate to obtain astaxanthin-containing sericin nanoparticles with a particle size of 50-200 nm.

[0046] Example 2

[0047] This embodiment provides a method for preparing sericin nanoparticles containing astaxanthin:

[0048] (1) Add the sericin powder to water while stirring until it is completely dissolved. Maintain a temperature of 40-42℃ during the dissolution process. After dissolution, filter through a 0.45μm filter membrane to obtain the first solution, in which the sericin concentration is 1%.

[0049] (2) At room temperature, add astaxanthin powder to anhydrous ethanol while stirring until completely dissolved. After dissolution, filter through a 0.45μm filter membrane to obtain a second solution with an astaxanthin concentration of 1%.

[0050] (3) Prepare the first solution and the second solution at a volume ratio of 3:1. Slowly add the second solution to the first solution while stirring at 3000 rpm. After the addition is complete, continue stirring for 15 min until a stable emulsion is formed. Treat the emulsion in a water bath and control the emulsification temperature to not exceed 25℃. Quickly transfer the emulsion to an ice bath and cool it rapidly to 4-8℃ for 1 h. Centrifuge at 10000g for 15 min. After centrifugation, separate the precipitate and freeze-dry the precipitate to obtain astaxanthin-containing sericin nanoparticles with a particle size of 100-300 nm.

[0051] Example 3

[0052] In this embodiment, astaxanthin-containing sericin nanoparticles prepared in Example 1 were used to formulate eye drops. The preparation process is as follows:

[0053] Add 0.1% chondroitin sulfate, 0.1% astaxanthin-containing sericin nanoparticles, 0.2% sodium hyaluronate, 0.05% vitamin E, 0.9% sodium chloride, 0.075% poloxamer, and 0.05% EDTA to sterile water and stir to disperse for 30 minutes. Finally, add phosphate buffer to adjust the pH of the eye drops to 7.4. After preparation, filter through a 0.22 μm filter membrane, dispense the filtered solution into sterile eye drop bottles, and then sterilize by irradiation with 20 kGy gamma rays at 4-8℃ before storage.

[0054] Example 4

[0055] In this embodiment, astaxanthin-containing sericin nanoparticles prepared in Example 2 were used to formulate eye drops. The preparation process is as follows:

[0056] Add 0.15% chondroitin sulfate, 0.15% astaxanthin-containing sericin nanoparticles, 0.1% sodium hyaluronate, 0.07% vitamin E, 0.95% sodium chloride, 0.070% poloxamer, and 0.04% EDTA to sterile water and stir to disperse for 30 min. Finally, add phosphate buffer to adjust the pH of the eye drops to 7.2. After preparation, filter through a 0.22 μm filter membrane, dispense the filtered solution into sterile eye drop bottles, and then sterilize by irradiation with 20 kGy gamma rays at 4-8℃ before storage.

[0057] Comparative Example 1

[0058] In this comparative example, the astaxanthin-containing sericin nanoparticles in the eye drop formulation of Example 3 were replaced with an equal amount of astaxanthin powder, which was not coated with sericin. All other conditions were the same as in Example 3. The pH was adjusted to 7.4, filtered through a 0.22 μm filter membrane, and sterilized by irradiation with 20 kGy gamma rays at 4-8°C to obtain the eye drops.

[0059] Comparative Example 2

[0060] In this comparative example, the sericin nanoparticles containing astaxanthin in Example 3 were replaced with a 3:1 ratio of sericin and astaxanthin. The sericin and astaxanthin were directly added to sterile water as raw materials, and all other conditions were the same as in Example 3. The pH was adjusted to 7.4, filtered through a 0.22 μm filter membrane, and sterilized by irradiation with 20 kGy gamma rays at 4-8°C to obtain eye drops.

[0061] Animal experiments:

[0062] (1) Laboratory animals and reagents

[0063] Animal selection: BALB / c mice, half female and half male, aged 8 weeks, were used to construct the dry eye syndrome. They were healthy and showed no observed ocular abnormalities. They were provided with adequate water and food, and kept in good husbandry conditions with controlled temperature and humidity.

[0064] (2) Animal grouping and administration

[0065] Forty-two mice were used to establish a dry eye model. The modeling method was as follows: Mice were housed in an experimental environment for a certain period of time, and pre-modeling preparations were made. Male and female mice of similar weight were selected and separated into different cages, with a blank control group of 6 mice. The remaining mice were used for the experimental model. After separation, a 2 mg / ml benzalkonium chloride (BAC) solution was prepared and applied to each eye with 5 μl of the prepared benzalkonium chloride solution, three times a day for 10 consecutive days. After the modeling began, the environment was kept relatively dry, and the mice were allowed normal food and water. Successful modeling was confirmed by the staining area and tear secretion volume. Figure 1-2 As shown, the staining of mouse eyes and tear secretion are compared before and after modeling. The comparison confirms that the modeling was successful.

[0066] Mice were randomly divided into seven groups: a blank control group, a negative control group, a positive control group, experimental group 1, experimental group 2, control group 1, and control group 2, with six mice in each group and twelve eyes in each group. The blank control group received no modeling and only instilled physiological saline. The negative control group received no medication after modeling. The positive control group received a commercially available eye drop. Experimental group 1, experimental group 2, control group 1, and control group 2 received the eye drops from Examples 3, 4, 1, and 2, respectively, after modeling (without additional medication). Administration was twice daily, 2 drops (approximately 5 μL) per eye each time, for 14 consecutive days. The administration method is shown in Table 1.

[0067] Table 1: Grouping and Administration Methods (Quantity is counted by the number of eyes)

[0068]

[0069] (3) Experimental results

[0070] ① On day 0 of successful dry eye model establishment, tear fluid was collected from mice in each group. Tear secretion was measured using phenol red cotton thread. Tear secretion was then measured again 14 days after drug administration. The specific procedure for phenol red cotton thread tear detection was as follows: the mouse was grasped, and the phenol red cotton thread was placed on the conjunctiva of the lower eyelid, one-third of the way from the outer corner of the eye, for 60 seconds. The thread was then removed and fixed, and the length (mm) of the moistened stained portion of the cotton thread was immediately measured and recorded. The results are shown in Table 2, where tear secretion is expressed as mean ± standard deviation.

[0071] Table 2: Tear secretion in mice before and after drug administration

[0072]

[0073] Table 2 shows that the tear secretion of mice without modeling remained at a normal level. After modeling treatment, the tear secretion of mice in the negative control group, positive control group, and experimental groups 1, 2, control groups 1, and control groups 2 was significantly reduced. The negative control group received only saline solution, and after 14 days of treatment, the tear secretion of mice in the negative control group further decreased. After 14 days of treatment, the tear secretion of mice in the positive control group, experimental groups 1, and 2 basically returned to normal levels, and the tear secretion of mice in experimental groups 1 and 2 was slightly better than that of the positive control group. After 14 days of treatment, the tear secretion of mice in control groups 1 and 2 also increased, but the increase was not significant.

[0074] ② Fluorescein staining: On day 0 of successful dry eye modeling and 14 days after drug administration, mice were stained with 0.25% fluorescein solution. After 10 seconds on the ocular surface, excess stain was rinsed off with 0.9% sodium chloride solution, and the ocular surface was dried with cotton swabs. The slit lamp light source was adjusted to cobalt blue light, and the mice's eyes were exposed under the slit lamp for observation. After adjusting the magnification, the staining of the cornea by fluorescein sodium in different groups of mice was recorded. The cornea was divided into four quadrants: superior temporal, inferior temporal, superior nasal, and inferior nasal. Each quadrant was scored from 0 to 3 points. The scoring criteria were: no staining 0 points; 1-30 punctate stains (mild) 1 point; more than 30 punctate stains but not fused (moderate) 2 points; corneal punctate staining fused, filamentous structures, and ulcers (severe) 3 points. Each corneal score was the sum of the scores of the four quadrants. The test results are shown in Table 3.

[0075] Table 3: Statistical table of corneal staining scores in mice before and after drug administration

[0076]

[0077] A lower corneal score indicates a higher degree of corneal epithelial repair and better eye recovery in mice, while a higher score indicates more severe corneal damage and poorer recovery. Table 3 shows that tear secretion remained at a normal level in mice without modeling. After modeling treatment, the corneal epithelial staining area and corneal score of mice in the negative control group, positive control group, experimental group 1, experimental group 2, control group 1, and control group 2 significantly increased. Specifically, the negative control group received only saline drops; after 14 days of treatment, the corneal epithelial staining area and score of mice in the negative control group further increased. In the positive control group, experimental group 1, and experimental group 2, after 14 days of treatment, the corneal epithelial staining area and score of mice significantly decreased, with experimental group 1-2 showing slightly better corneal improvement than the positive control group. In control group 1 and control group 2, after 14 days of treatment, the corneal epithelial staining area and score of mice also decreased slightly, indicating that the degree of corneal epithelial repair in mice was not significant.

[0078] ③ Detection of IL-1β levels, a inflammatory factor in mouse corneas, using the following method:

[0079] Two mice were randomly selected from each group and sacrificed. Immediately afterward, the eyeballs were removed. Under a microscope, the eyeballs were separated using ophthalmic forceps, rinsed with pre-cooled PBS, and dried with filter paper. The two corneas were assembled into an enzyme-free EP tube and frozen in liquid nitrogen for temporary storage at -80°C. The corneal tissue was removed and placed in an ice box. The tissue was minced using sterilized ophthalmic instruments. 100 μl of pre-cooled PBS containing PMSF was added to each sample tube, and the samples were sonicated on ice for 3 min using an ultrasonic homogenizer. The sonicated samples were centrifuged in a frozen centrifuge at 4°C and 12,000 rpm for 15 min. The supernatant was collected and placed in an enzyme-free EP tube for later use.

[0080] Serial dilution of bovine serum albumin (BSA) standard. Prepare BCA working solution, typically by mixing BCA reagents A and B in a 50:1 ratio. Add the standard and the sample to be tested to a microplate or test tube, then add the BCA working solution and mix well. Incubate at 37°C for 30-60 minutes, or at room temperature for 2 hours. After cooling to room temperature, measure the absorbance of the sample at 562 nm.

[0081] After equilibrating the ELISA kit to room temperature, remove only the required number of strips according to the experimental needs before detection, and keep the rest sealed and stored at 4°C. Add 50 μl of sample to each well according to the experimental settings. Add 100 μl of HRP-labeled detection antibody to each well, seal with a sealing film, and incubate at 37°C for 60 min. After the reaction, wash the plate with washing buffer for 1 min each time, repeating 5 times. Add substrate A and substrate B sequentially to each well, 50 μl each, and incubate at 37°C in the dark for 15 min. After the reaction, add 50 μl of stop solution. Measure the OD value of each well at the wavelength specified in the kit using a microplate reader. Note that the detection should be completed within 15 min of adding the stop solution. Finally, plot a standard curve, calculate the sample concentration, and correct the results using the protein concentration of the sample. Experimental results are as follows: Figure 3 As shown.

[0082] like Figure 3As shown, the blank control group consisted of healthy mice (without modeling treatment) with low levels of inflammation. The negative control group, after successful modeling, only received saline solution. After 14 days of treatment, their levels of the inflammatory factor IL-1β were high, indicating that corneal inflammation in the negative control group mice remained significant. After 14 days of treatment, the inflammatory expression levels in the positive control group, Experiment 1 group, and Experiment 2 group decreased significantly, all approaching those of the blank control group. This demonstrates that the eye drops prepared in Examples 3-4 can indeed significantly inhibit the expression of the inflammatory factor IL-1β in the cornea of ​​dry eye mice. Compared with commercially available eye drop products, the eye drops prepared in Examples 3-4 of this invention have a superior inhibitory effect on the inflammatory factor IL-1β. Although Comparative Examples 1-2 also inhibited the inflammatory factor IL-1β, their overall effect was not as good as that of the eye drops prepared in Examples 3-4. Compared with Comparative Example 1, Comparative Example 2 showed a better ability to inhibit inflammatory factors, indicating that sericin also has the effect of inhibiting the expression level of inflammatory factors.

[0083] Eye Drops Storage Stability Test

[0084] The eye drop samples prepared in Example 3 and Comparative Examples 1-2 were stored in sealed containers and kept in the dark at 25°C for 16 weeks. Samples were taken every 4 weeks to measure the astaxanthin content, and the retention rate of astaxanthin (reduced form) in the eye drop samples was determined by HPLC. The test results are as follows: Figure 4 As shown in the figure, the astaxanthin-containing eye drops prepared in Example 3 of this invention can remain stable for a longer period of time at room temperature, while the astaxanthin in the astaxanthin eye drops prepared in Comparative Examples 1-2 is difficult to retain for a long time, and the astaxanthin is likely to undergo partial degradation during preparation, irradiation sterilization, and storage.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An eye drop for dry eye syndrome, characterized in that, It comprises, by mass percentage: 0.1%-0.5% chondroitin sulfate, 0.06%-0.3% sericin nanoparticles containing astaxanthin, 0.1%-0.3% sodium hyaluronate, 0.05%-0.1% vitamin E, 0.9%-1.0% sodium chloride, 0.05%-0.1% poloxamer, 0.01%-0.1% EDTA, phosphate buffer, and the balance being water; wherein the astaxanthin-containing sericin nanoparticles have a particle size of 50-300 nm; the phosphate buffer adjusts the pH of the eye drops to 6.8-7.

9.

2. The dry eye eye drops according to claim 1, characterized in that, The dry eye drops are composed of: 0.1% chondroitin sulfate, 0.1% sericin nanoparticles containing astaxanthin, 0.2% sodium hyaluronate, 0.05% vitamin E, 0.9% sodium chloride, 0.075% poloxamer, 0.05% EDTA, phosphate buffer, and the balance being water; the pH of the eye drops is 7.

4.

3. The dry eye eye drops according to claim 1, characterized in that, The eye drops do not contain chemical preservatives.

4. A method for preparing the dry eye eye drops according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of sericin nanoparticles containing astaxanthin The first solution is prepared by dissolving sericin in water or phosphate buffer, and the second solution is prepared by dissolving astaxanthin in anhydrous ethanol or 95% ethanol. The second solution is added to the first solution and the mixture is subjected to high-speed stirring or ultrasonic treatment to form a stable emulsion. The emulsion is then cooled to 2-8°C, centrifuged, and the precipitate is separated and freeze-dried to obtain sericin nanoparticles containing astaxanthin. S2. Add sodium chloride, sodium hyaluronate, chondroitin sulfate, sericin nanoparticles containing astaxanthin, vitamin E, poloxamer, and EDTA to sterile water. Stir well, then add phosphate buffer and stir well again. Adjust the pH to 6.8-7.9, filter through a 0.22μm filter membrane, and dispense the filtered solution into sterile eye drop bottles.

5. The preparation method according to claim 4, characterized in that, In S1, the concentration of sericin in the first solution is 1-5%. The preparation process of the first solution is as follows: add sericin powder to water or phosphate buffer while stirring until completely dissolved. During the dissolution process, control the temperature at 25-45℃. After dissolution, filter through a 0.45μm filter membrane to obtain the first solution.

6. The preparation method according to claim 5, characterized in that, In S1, the concentration of astaxanthin in the second solution is 0.1-1%; the preparation process of the second solution is as follows: at room temperature, astaxanthin powder is added to anhydrous ethanol or 95% ethanol while stirring until it is completely dissolved. After dissolution, it is filtered through a 0.45μm filter membrane to obtain the second solution.

7. The preparation method according to claim 5 or 6, characterized in that, In step S1, the first solution and the second solution are prepared at a volume ratio of 5:1 to 1:

1. The second solution is slowly added to the first solution while stirring at high speed at 1000-3000 rpm for 10-30 minutes until a stable emulsion is formed. The temperature during emulsification does not exceed 25°C. Then, the emulsion is quickly transferred to an ice bath or refrigerator and rapidly cooled to 4-8°C for 0.5-1 hour. It is then centrifuged at 10000-15000g for 10-20 minutes. After centrifugation, the precipitate is separated and freeze-dried to obtain sericin nanoparticles containing astaxanthin.

8. The preparation method according to claim 7, characterized in that, In S1, the supernatant separated after centrifugation at 10000-15000g for 10-20min is recovered, sterilized, and used to prepare the first solution.

9. The preparation method according to claim 4, characterized in that, In S2, after being dispensed into sterile eye drop bottles, the solution is sterilized by irradiation with 10-20 kGy gamma rays at 4-10℃ before being stored.

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