Eye drops containing tosufloxacin tosylate and dexamethasone and preparation method thereof

Abstract

The invention discloses eye drops containing tosufloxacin tosylate and dexamethasone and a preparation method of the eye drops, and belongs to the technical field of medicines. Comprising the following raw materials in parts by weight: 2-4 parts of tosufloxacin tosylate, 1-6 parts of dexamethasone, 0.4-0.6 part of polysorbate 20, 5-10 parts of a thickening agent, 8-9 parts of sodium chloride, a proper amount of a pH regulator, 0.03-0.04 part of a preservative and 1000 parts of purified water. The preparation method comprises the following steps: constructing temperature-sensitive hydrogel through a thickening agent, embedding suspended dexamethasone particles into the temperature-sensitive hydrogel, and then forming the gel eye drops together with soluble tosufloxacin tosylate. The eye drops have temperature sensitivity, are gel in a contraction state at low temperature, swell due to temperature change after being dropped into eyes, and slowly release dexamethasone particles, so that local excessive administration caused by drug aggregation is avoided, the stimulation to the eyes is effectively reduced, and the use comfort of a patient is improved.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical technology, and in particular to an eye drop containing tosufloxacin tosylate and dexamethasone, and a method for preparing the same. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In the field of ophthalmology, inflammatory eye diseases are quite common, such as blepharitis, dacryocystitis, and conjunctivitis. Currently, antibiotic eye drops are a commonly used treatment for these diseases, such as tosufloxacin tosylate eye drops, which belong to the fluoroquinolone class and have good therapeutic effects against various bacterial eye infections. However, with the widespread use of antibiotics, the problem of antibiotic resistance in eye drops has become increasingly prominent, leading to a gradual decline in treatment effectiveness.

[0004] Dexamethasone, a long-acting glucocorticoid, possesses potent and sustained anti-inflammatory effects, effective against both infectious and non-infectious inflammation. In ophthalmological treatment, the combined use of antibiotics and corticosteroids can theoretically provide a more effective treatment strategy by exerting a dual therapeutic effect on both bacterial infections and inflammation. However, current technology for simply mixing antibiotics and corticosteroids to create eye drops presents several problems. On the one hand, when dexamethasone is suspended in solution as micron-sized particles, its large surface area makes it prone to aggregation. This not only leads to uneven distribution of the drug in the eye but may also cause local overdose, resulting in significant eye irritation. On the other hand, achieving effective synergy between the two drugs, while ensuring drug stability and improving patient comfort, remains a pressing technical challenge. Summary of the Invention

[0005] In view of this, the present invention provides an eye drop containing tosufloxacin tosylate and dexamethasone, and a method for preparing the same.

[0006] In a first aspect, the present invention provides an eye drop containing tosufloxacin tosylate and dexamethasone, comprising the following raw materials in parts by weight: 2-4 parts tosufloxacin tosylate, 1-6 parts dexamethasone, 0.4-0.6 parts polysorbate 20, 5-10 parts thickener, 8-9 parts sodium chloride, appropriate amount of pH adjuster, 0.03-0.04 parts preservative, and 1000 parts purified water.

[0007] Polysorbate 20 adsorbs onto the surface of dexamethasone particles. Its hydrophilic groups face outwards, while its hydrophobic groups interact with the particle surface, forming a protective film around the particles. Through encapsulation and high-pressure homogenization, polysorbate 20 maintains the dexamethasone particles in a uniformly dispersed micron-sized state. It also allows the particles to be easily embedded in the three-dimensional network structure of the thermosensitive hydrogel and uniformly distributed within the gel matrix. Further processing, including ultrasonic mixing, completely resolves the issue of dexamethasone micron-sized particle aggregation, preventing local overdose, significantly reducing eye irritation, and improving patient comfort and compliance. When eye drops are instilled into the eye, as the thermosensitive hydrogel swells and releases the drug with temperature changes, polysorbate 20 helps release the dexamethasone particles at an appropriate rate and in a suitable manner.

[0008] Preferably, the thickener is selected from one or more of hydroxypropyl methylcellulose, sodium hyaluronate, and poloxamer 407; Preferably, the thickener is hydroxypropyl methylcellulose and sodium hyaluronate, with a weight ratio of hydroxypropyl methylcellulose to sodium hyaluronate of 5:1 to 1:5. When the thickener is a combination of hydroxypropyl methylcellulose and sodium hyaluronate, and the weight ratio is controlled at 5:1 to 1:5, this combination forms a thermosensitive physical cross-linked network in the formulation: the methoxy groups on the hydroxypropyl methylcellulose molecular chain and the carboxyl and acetamino groups on the sodium hyaluronate molecular chain interact through hydrogen bonds and hydrophobic interactions. At low temperatures (below 25°C), the movement of molecular chain segments is restricted, and the network is in a contracted and dense state. After being instilled onto the ocular surface, the temperature rises to 32-35°C, the molecular thermal motion intensifies, the hydrogen bonds partially dissociate, the network gradually swells, and the porosity increases. During the preparation process, dexamethasone microparticles are uniformly embedded in the pores of the network with the aid of ultrasound. During storage, the particles are physically isolated by the gel skeleton and cannot come into contact with each other, thus preventing aggregation at the source. When the eye drops are applied, the network contracts and the particles are bound within it. Unlike ordinary suspensions, the particles do not pour out in large quantities onto the ocular surface, but are slowly released as the gel swells.

[0009] Preferably, the pH adjuster is sodium hydroxide and / or hydrochloric acid. This allows for precise adjustment of the eye drops' pH value, bringing it close to the physiological pH range of the eye, reducing eye irritation, improving patient tolerance, and ensuring the stability and activity of the drug.

[0010] Preferably, the preservative is selected from one or more of benzalkonium chloride, borax, chlorobutanol, chlorhexidine, and ethylparaben. This effectively prevents microbial contamination of the eye drops during use and storage, ensuring product quality and safety, extending shelf life, and ensuring patients receive safe and effective medication.

[0011] Preferably, the pH of the eye drops is 6.6-7.0. Controlling the pH of the eye drops within the range of 6.6-7.0 is compatible with the physiological pH of the eye, minimizing irritation to eye tissues, improving patient comfort, and facilitating drug absorption and efficacy.

[0012] Secondly, the present invention provides a method for preparing the above-mentioned eye drops containing tosufloxacin tosylate and dexamethasone, comprising the following steps: (1) Dexamethasone and polysorbate 20 were dispersed in purified water, sterilized, cooled, and homogenized under high pressure to obtain a dexamethasone dispersion; (2) Weigh the thickener, add an appropriate amount of purified water, swell, and prepare a gel matrix; (3) Add the dexamethasone dispersion to the gel matrix and mix thoroughly by ultrasonication to obtain the first solution. (4) Dissolve tosufloxacin tosylate, sodium chloride, and preservative in purified water to obtain a second solution; (5) Mix the first solution and the second solution evenly, add pH adjuster to adjust pH value, add purified water to the full volume, filter through filter membrane, and fill into a sealed container to obtain the final product.

[0013] Preferably, in step (1), the sterilization temperature is 110-130℃, the sterilization time is 14-16min, the pressure of high-pressure homogenization is 700-800bar, the flow rate is 20-30Hz, and the number of homogenizations is 2-4.

[0014] Preferably, in step (2), the swelling stirring temperature is 30-50℃, the swelling stirring rate is 100-200 rpm, and the temperature is cooled to room temperature after swelling.

[0015] Preferably, in step (3), the ultrasonic frequency is 35-45KHz and the ultrasonic time is 8-15min.

[0016] Preferably, in step (5), the pH value is adjusted to 6.6-7.0, and the filter membrane is a PVDF filter membrane.

[0017] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) The present invention combines tosufloxacin tosylate with dexamethasone to create a synergistic effect between the antibacterial and anti-inflammatory components. This not only enhances the antibacterial activity of tosufloxacin tosylate and reduces the probability of drug resistance, but also rapidly relieves ocular inflammation through dexamethasone. Compared with single eye drops, this invention significantly improves the treatment efficiency of ocular inflammatory diseases, shortens the course of the disease, and reduces recurrence.

[0018] (2) This invention constructs a thermosensitive hydrogel using a thickener, embeds suspended dexamethasone particles into the thermosensitive hydrogel, and then combines it with soluble tosufloxacin tosylate to form a gel eye drop. The steric hindrance of the gel network effectively prevents the dexamethasone particles from colliding and agglomerating, ensuring accurate dosage and uniform distribution. This eye drop is temperature-sensitive; the gel, which is in a contracted state at low temperatures, swells upon instillation into the eye due to temperature changes, slowly releasing the dexamethasone particles. This avoids drug agglomeration leading to local overdose, effectively reducing eye irritation and improving patient comfort.

[0019] (3) The preparation method of the present invention is simple and easy to apply in industrial production. Attached Figure Description

[0020] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Obviously, those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0021] Figure 1 Representative images of HE staining in the normal group (bar=100μm); Figure 2 Representative images of HE staining in the model group (bar=100μm); Figure 3 Representative HE staining images of the positive control group (bar=100μm); Figure 4 Representative images of HE staining in Example 1 (bar=100μm); Figure 5 Representative images of HE staining in Example 4 (bar=100μm); Figure 6 This is a representative image of HE staining in Comparative Example 1 (bar=100μm). Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0024] Example 1 This embodiment provides an eye drop containing tosufloxacin tosylate and dexamethasone, the formulation of which is shown in Table 1.

[0025] The preparation method of the eye drops containing tosufloxacin tosylate and dexamethasone is as follows: (1) Add the prescribed amount of dexamethasone to polysorbate 20, stir into a paste, add 100 ml of water, stir to disperse the dexamethasone in the solution; place in an autoclave for sterilization at 121°C for 15 min, remove after sterilization and cool to 30°C. Then perform high-pressure homogenization, setting the homogenizer pressure to 800 bar and the flow rate to 25 Hz, homogenize 3 times to obtain dispersed dexamethasone particles.

[0026] (2) Measure 400ml of purified water, add the prescribed amount of hydroxypropyl methylcellulose, stir to disperse, stir at 40℃ and 150rpm until the hydroxypropyl methylcellulose is completely swollen, and then cool to room temperature.

[0027] (3) Measure 200ml of purified water, add the prescribed amount of sodium hyaluronate, stir to disperse, stir at 35℃ and 120rpm until the sodium hyaluronate is completely swollen, and then cool to room temperature.

[0028] (4) Stir and mix the swelled hydroxypropyl methylcellulose from step (2) and the swelled sodium hyaluronate from step (3) until they are evenly mixed and ready for use.

[0029] (5) Add the dexamethasone solution particles dispersed in step (1) to step (4), and then mix them evenly by ultrasonication at a frequency of 40 kHz for 10 min to obtain the first solution.

[0030] (6) Take 200 ml of purified water, then add the prescribed amount of sodium chloride, benzalkonium chloride and tosufloxacin toluene, stir and mix evenly to obtain the second solution.

[0031] (7) Add the second solution from step (6) to the first solution from step (5), stir and mix evenly, then adjust the pH to 7.0 with sodium hydroxide, then add purified water to 1000ml, make up the volume, filter through 0.45μm and 0.22μm PVDF filter membranes, and then fill into 5ml / vial.

[0032] Example 2 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.9, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 1.

[0033] Example 3 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 1.

[0034] Example 4 The difference between this embodiment and Example 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.9, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in Example 4 is shown in Table 1.

[0035] Example 5 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 7.0, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 2.

[0036] Example 6 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 2.

[0037] Example 7 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 2.

[0038] Example 8 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 2.

[0039] Example 9 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.9, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 3.

[0040] Example 10 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 3.

[0041] Example 11 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.7, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 3.

[0042] Example 12 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.9, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 3.

[0043] Example 13 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 4.

[0044] Example 14 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.8, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 4.

[0045] Example 15 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 7.0, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 4.

[0046] Example 16 The difference between this embodiment and embodiment 1 is that in step (7), sodium hydroxide is used to adjust the pH to 6.7, and the composition of the eye drops containing tosufloxacin tosylate and dexamethasone in this embodiment is shown in Table 4.

[0047] Comparative Example 1 The composition of the eye drops in Comparative Example 1 is shown in Table 5.

[0048] The preparation method of this eye drop is as follows: (1) Measure 400ml of purified water, add the prescribed amount of hydroxypropyl methylcellulose, stir to disperse, stir at 40℃ and 150rpm until the hydroxypropyl methylcellulose is completely swollen, and then cool to room temperature.

[0049] (2) Measure 200ml of purified water, add the prescribed amount of sodium hyaluronate, stir to disperse, stir at 35℃ and 120rpm until the sodium hyaluronate is completely swollen, and then cool to room temperature.

[0050] (3) Mix the swelled hydroxypropyl methylcellulose from step (1) and the swelled sodium hyaluronate from step (2) until homogeneous, and set aside for later use. (4) Take 200ml of purified water, then add the prescribed amount of sodium chloride, benzalkonium chloride and tosufloxacin tosylate and stir until well mixed.

[0051] (5) Add the solution from step (4) to step (3), stir and mix evenly, then adjust the pH to 7.0 with sodium hydroxide, then add purified water to 1000ml, make up the volume, filter through 0.45μm and 0.22μm PVDF filter membranes, and then fill into 5ml / vial.

[0052] Comparative Examples 2-3 Eye drops containing tosufloxacin tosylate and dexamethasone were prepared according to the preparation method of Example 1. The compositions of eye drops in Comparative Examples 2-3 are shown in Table 5.

[0053] Table 1. Composition of eye drops containing tosufloxacin tosylate and dexamethasone in Examples 1-4

[0054] Table 2. Composition of eye drops containing tosufloxacin tosylate and dexamethasone in Examples 5-8

[0055] Table 3. Composition of eye drops containing tosufloxacin tosylate and dexamethasone in Examples 9-12

[0056] Table 4. Composition of eye drops containing tosufloxacin tosylate and dexamethasone in Examples 13-16

[0057] Table 5. Composition of eye drops in Comparative Examples 1-3

[0058] Experimental Example 1 pH, properties, molar osmotic pressure, viscosity, and relative density were determined according to the draft quality standard (the determination items in the draft quality standard were performed in accordance with the Chinese Pharmacopoeia 2025 standard). The results are shown in Table 6.

[0059] Table 6: Performance data of eye drops from Examples 1-16 and Comparative Examples 1-3

[0060] As shown in Table 6, the eye drops prepared by this invention all meet the requirements for appearance and pH. Examples 1-4 show that samples with the expected quality are obtained when the ratio of tosufloxacin to dexamethasone is 3:1, 3:3, 3:4.5, and 3:6. Examples 5-8 show that the quality of the thermosensitive eye drops obtained when the ratio of hydroxypropyl methylcellulose to sodium hyaluronate in the thermosensitive hydrogel is 5:1, 3:3, 2:4, and 1:5 meets the expectations. Examples 9-12 show that samples with the expected quality are obtained when the thickener is one or two of hydroxypropyl methylcellulose, sodium hyaluronate, or poloxamer 407. Examples 13-16 show that samples with the expected quality are obtained when the preservatives are borax, chlorobutanol, chlorhexidine, and ethylparaben.

[0061] Experimental Example 2 Stability test The eye drops of Examples 1-16 and Comparative Examples 1-3 were subjected to accelerated stability testing in a 40℃±2℃ stability incubator for 30 days. Samples were taken periodically during this period to investigate the stability of the formulations under high-temperature conditions. The results are shown in Tables 7 and 8.

[0062] Table 7. Stability data of eye drops containing tosufloxacin tosylate and dexamethasone from Examples 1-16

[0063] As can be seen from Table 7, the eye drops prepared by this invention have good stability.

[0064] Table 8. Stability data of eye drops for comparative examples 1-3

[0065] As can be seen from Table 8, the eye drops formed by Comparative Example 2 lacking polysorbate 20 have poor stability; the eye drops formed by Comparative Example 3 lacking thickener have poor stability.

[0066] Experimental Example 3 The antibacterial efficacy test was conducted according to the antibacterial efficacy test method 1121 of the 2020 edition of the Chinese Pharmacopoeia, and the results are shown in Table 9.

[0067] Table 9. Results of antibacterial efficacy of eye drops containing tosufloxacin tosylate and dexamethasone in Examples 2, 13-16.

[0068] As can be seen from Table 9, gel eye drops using benzalkonium chloride, borax, chlorobutanol, chlorhexidine, and ethylparaben showed good antibacterial and antifungal effects.

[0069] Experimental Example 4: Drug Efficacy Test 1. Route of administration The test sample is intended for clinical use via eye drops, therefore the eye drop method was adopted for administration.

[0070] 2. Dosage design and basis Positive control and examples: Clinically prescribed dosage: The clinically prescribed dosage for each person is 1-2 drops three times a day. This trial used a slightly higher dosage than the clinically prescribed dosage, with all five prescriptions set at 2 drops four times a day.

[0071] 3. Animal identification after grouping Each animal was identified using animal tagging and cage tagging methods.

[0072] 3.1 Animal Marking Each group of animals was numbered 1-6. Picric acid was applied to different parts of the animals' fur to mark them. The marking locations are shown in Table 10.

[0073] Table 10 Marked Locations

[0074] 3.2 Cage Marking After grouping the animals, different groups are labeled with cage tags of different colors. The tags include: project number, cage number, sex, group, animal number, project leader, contact number, and experiment start and end dates. The completed cage tags are hung on the front of the enclosure.

[0075] 4. Animal Model Preparation Under local anesthesia with tetracaine eye drops, the eyelids are fully opened using an eyelid speculum. A No. 7 corneal trephine is used to gently press the conjunctiva in a clockwise direction, causing a ring-shaped injury to the conjunctiva, ideally reaching the Bowman's layer. Two 2×10⁻⁶ drops are then pipetted into the eyelid. 9 / ml of Pseudomonas aeruginosa bacterial solution was dropped onto the conjunctiva of the eye, 0.1ml per eye, infecting the left eye, while the right eye was left untreated, thus creating an animal model of conjunctivitis.

[0076] 5. Animal grouping Group design: A total of 6 groups were set up, namely blank control group, model group, positive control group, Example 1, Example 4 and comparative example 1 prescription group.

[0077] Number of animals: 6 animals per group, totaling 36 animals; Sex ratio: hermaphroditic; Grouping method: On the 3rd day after modeling, animals with successful membrane formation were selected and grouped evenly according to rabbit eye scores.

[0078] See Table 11 below for specific group information.

[0079] Table 11 Dosing regimen and grouping information

[0080] 6. Administration Administer the drug daily for 10 consecutive days. After grouping, administer the drug to the left eye of each animal in the treatment group, with the corresponding positive control or test drug given 4 times a day, 2 drops each time. The model group and the blank group were given an equal volume of physiological saline.

[0081] 7. Indicator Testing 7.1 Weight Measurement Adaptation period: 2 times (the day after purchase and the day of grouping). Dosage period: Test once every 5 days Animals tested: surviving animals in each group During the experiment, the body weight of the model group animals was basically the same as that of the normal group animals (p>0.05); the positive control group, Example 1, Example 4, and Comparative Example 1 groups were basically the same as the model group (p>0.05). This indicates that conjunctivitis modeling has no effect on animal body weight, and the test products also have no effect on the body weight of the model group animals.

[0082] The results are shown in Table 12.

[0083] Table 12 Body weight of rabbits with bacterial conjunctivitis ( ±S, n=6)

[0084] Note: p > 0.05, compared with the model group.

[0085] 7.0 Symptom Observation Measurement time: 72 hours after modeling, and 2, 4, 8, and 10 days after drug administration.

[0086] Animals tested: Surviving animals in each group.

[0087] Grading Criteria: Ulcers: Ulcers covering more than 70% of the eyeball: 5 points; 50% to less than 70%: 4 points; 30% to less than 50%: 3 points; 20% to less than 30%: 2 points; 1% to less than 20%: 1 point; No ulcers: 0 points. Discharge: Abnormally large discharge: 3 points; Large discharge: 2 points; Small discharge: 1 point; Minimal or no discharge: 0 points. Eyelid Redness and Swelling: Eyelids that are both red and swollen: 2 points; Eyelids that are only red and not swollen: 1 point; Eyelids that are neither red nor swollen: 0 points.

[0088] Eye symptom observation and scoring: The normal control group of New Zealand rabbits had normal eyeballs without discharge, ulcers, or redness and swelling, and their scores were 0 during the experiment. 72 hours after membrane creation, the New Zealand rabbits exhibited abundant discharge, numerous ulcers, and significant redness and swelling. The model group showed slight spontaneous relief of eye symptoms during the observation period, with a slight decrease in scores. All four prescription groups showed varying degrees of improvement with prolonged administration, with Example 1 and Example 4 showing the most significant improvement. Examples 1 and 4 showed significant differences in scores compared to the model group starting from day 4 of administration (p < 0.05 or p < 0.01). The positive control group showed the second best effect, showing a significant difference in scores compared to the model group starting from day 8 of administration (p < 0.05), but its score was higher than that of the control group (Example 1). The eye score of the control group also decreased to some extent, but there was no significant difference compared to the model group (p > 0.05). The results are shown in Table 13.

[0089] Table 13 Observational scores of rabbit eyes with bacterial keratitis ( ±S, n=6)

[0090] Note: p < 0.05 p < 0.01, compared with the model group; p > 0.05, compared with the model group.

[0091] Under the conditions of this experiment, Examples 1 and 4 showed significant therapeutic effects on bacterial keratitis in New Zealand rabbits starting on day 4 of administration, but the data for Example 4 were slightly better than those for Example 1; the positive control group showed therapeutic effects starting on day 8 of administration; and Comparative Example 1 also showed a weak therapeutic effect, but its effect was far less than that of Examples 1 and 4.

[0092] 7.1 Pathological examination Twelve hours after the last administration, the animals were euthanized, and the eyeballs were dissected, fixed in formaldehyde, dehydrated, embedded, sectioned, and stained with hematoxylin and eosin (HE).

[0093] Pathological examination results.

[0094] like Figure 1 As shown, in the solvent control group: the corneal epithelium was intact, the corneal stromal fibers were arranged in an orderly manner, and no obvious inflammatory cell infiltration was observed.

[0095] like Figure 2 As shown in the model group: the corneal layer is significantly swollen and thickened, the epithelium is shed to form ulcers, the stromal part has a loose fibrous structure, and neovascularization is visible. A large number of lymphocytes and neutrophils infiltrate the corneal stroma under the corneal epithelium.

[0096] like Figure 3As shown, in the positive control group: the corneal epithelium was intact, the corneal stromal was edematous, and fibroblast proliferation and neovascularization were visible under the corneal epithelium. Some samples showed a small amount of inflammatory cell infiltration at the angle of the anterior chamber and under the epithelium.

[0097] like Figure 4 As shown in Example 1: The corneal epithelial inflammation was reduced, and no obvious inflammatory cell infiltration was observed; the underlying stroma was slightly swollen, fibroblast proliferation was visible, and neovascularization was observed in some areas.

[0098] like Figure 5 As shown in Example 4: The corneal epithelium is intact, the corneal stromal fibers are arranged in an orderly manner, and some samples show loose tissue arrangement and corneal epithelial hyperplasia. There is no obvious inflammatory reaction and no inflammatory cell infiltration.

[0099] like Figure 6 As shown in Comparative Example 1: The corneal epithelium is intact, the corneal stroma is mildly edematous, and some samples show corneal epithelial repair and proliferation, as well as vascular dilation in the iris and ciliary body.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An eye drop containing tosufloxacin tosylate and dexamethasone, characterized in that, The ingredients include the following parts by weight: 2-4 parts tosufloxacin tosylate, 1-6 parts dexamethasone, 0.4-0.6 parts polysorbate 20, 5-10 parts thickener, 8-9 parts sodium chloride, appropriate amount of pH adjuster, 0.03-0.04 parts preservative, and 1000 parts purified water.

2. The eye drops containing tosufloxacin tosylate and dexamethasone as described in claim 1, characterized in that, The thickener is selected from one or more of hydroxypropyl methylcellulose, sodium hyaluronate, and poloxamer 407. Preferably, the thickener is hydroxypropyl methylcellulose and sodium hyaluronate, and the weight ratio of hydroxypropyl methylcellulose to sodium hyaluronate is 5:1 to 1:

5.

3. The eye drops containing tosufloxacin tosylate and dexamethasone as described in claim 1, characterized in that, The pH adjuster is sodium hydroxide and / or hydrochloric acid.

4. The eye drops containing tosufloxacin tosylate and dexamethasone as described in claim 1, characterized in that, The preservative is selected from one or more of benzalkonium chloride, borax, chlorobutanol, chlorhexidine, and ethylparaben.

5. The eye drops containing tosufloxacin tosylate and dexamethasone as described in claim 1, characterized in that, The pH of the eye drops is 6.6-7.

0.

6. A method for preparing an eye drop containing tosufloxacin tosylate and dexamethasone according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Dexamethasone and polysorbate 20 were dispersed in purified water, sterilized, cooled, and homogenized under high pressure to obtain a dexamethasone dispersion; (2) Weigh the thickener, add an appropriate amount of purified water, swell, and prepare a gel matrix; (3) Add the dexamethasone dispersion to the gel matrix and mix thoroughly by ultrasonication to obtain the first solution. (4) Dissolve tosufloxacin tosylate, sodium chloride, and preservative in purified water to obtain a second solution; (5) Mix the first solution and the second solution evenly, add pH adjuster to adjust pH value, add purified water to the full volume, filter through filter membrane, and fill into a sealed container to obtain the final product.

7. The preparation method according to claim 6, characterized in that, In step (1), the sterilization temperature is 110-130℃, the sterilization time is 14-16min, the pressure of high pressure homogenization is 700-800bar, the flow rate is 20-30Hz, and the number of homogenizations is 2-4.

8. The preparation method according to claim 6, characterized in that, In step (2), the swelling stirring temperature is 30-50℃, the swelling stirring rate is 100-200 rpm, and the temperature is cooled to room temperature after swelling.

9. The preparation method according to claim 6, characterized in that, In step (3), the ultrasonic frequency is 35-45KHz and the ultrasonic time is 8-15min.

10. The preparation method according to claim 6, characterized in that, In step (5), the pH value is adjusted to 6.6-7.0, and the filter membrane is a PVDF filter membrane.

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