Drug-loaded contact lenses and methods of making the same

Abstract

This invention discloses a drug-loaded contact lens and its preparation method, which includes a drug-loaded coating disposed on the surface of the contact lens substrate. The drug-loaded coating contains a variety of polyvinyl alcohols with different degrees of hydrolysis. Through a simple and industrially scalable preparation process, a drug-loaded contact lens that can have both good hydrophilicity and controllable drug release time can be obtained.

Description

Technical Field

[0001] This invention belongs to the field of contact lens technology, and particularly relates to a sustained-release drug-loaded contact lens and its preparation method. Background Technology

[0002] Currently, the main methods of drug administration for treating ophthalmic diseases are traditional eye drops, ointments, and gels. Eye drops, as the most commonly used method, have very low bioavailability, with over 90% of the drug lost during conjunctival absorption or tear drainage. Furthermore, traditional methods result in excessively high drug concentrations in the first few minutes of administration, but these concentrations drop below the therapeutic level over time until the next administration time. In contrast, sustained-release drug-eluting contact lenses can remain on the cornea for an extended period, providing slow and stable drug delivery while correcting vision, thus reducing the frequency of medication use for patients.

[0003] Currently, drug-loaded contact lenses prepared by the commonly used drug impregnation method, although simple in process, can experience drug burst release. While drug-loaded contact lenses prepared by nanoparticle embedding / embedding have solved the problem of drug burst release, the process is complex and the production cost is high, which is not conducive to industrialization.

[0004] Polyvinyl alcohol (PVA) is a water-soluble polymer commonly used in the medical aesthetics field to prepare drug-loaded membranes or microneedles. For example, patent CN110538166B provides a PVA sustained-release membrane, PVA sustained-release microneedles, and their preparation method. This method utilizes the different responses of PVA with varying degrees of alcoholysis to crosslinking reactions under high-temperature conditions to prepare PVA sustained-release membranes or microneedles with different drug release times. However, when applying PVA to drug-loaded coatings for contact lenses, how to balance the comfort of contact lens wear with a controllable drug release time has not yet been effectively resolved.

[0005] Therefore, it is of great significance to develop an ideal drug-eluting contact lens that is safe in composition, simple in process, and can balance drug release time and good hydrophilicity. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention controls the drug release time and hydrophilicity of contact lenses by adjusting the types and ratios of polyvinyl alcohols with different degrees of hydrolysis, along with varying ultraviolet light intensities and irradiation durations. This provides a simple, safe, and easily mass-producible preparation method that maintains good hydrophilicity during wear and allows for slow swelling and dissolution to release the drug, achieving continuous drug delivery.

[0007] According to one embodiment of the present invention, a drug-loaded contact lens includes a contact lens substrate and a drug-loaded coating disposed on the front and / or rear surface of the substrate. The drug-loaded coating is composed of a polyvinyl alcohol film and a drug distributed therein. The polyvinyl alcohol film is composed of at least one polyvinyl alcohol having a first degree of hydrolysis of 89%-95% and at least one polyvinyl alcohol having a second degree of hydrolysis of 66%-77%, and the mass ratio of the polyvinyl alcohols corresponding to the two degree of hydrolysis ranges is 1:1-3.

[0008] Furthermore, the first degree of alcoholysis is preferably 89%-94%, more preferably 89%-92%; the second degree of alcoholysis is preferably 70%-77%, more preferably 70%-75%.

[0009] Furthermore, the mass ratio of polyvinyl alcohol in the first degree of hydrolysis range to polyvinyl alcohol in the second degree of hydrolysis range is preferably 1:1.5-2.5, more preferably 1:2-2.5.

[0010] According to another embodiment of the present invention, the polyvinyl alcohol film in the drug-loaded coating of the drug-loaded contact lens is composed of a polyvinyl alcohol having a first degree of hydrolysis range and two polyvinyl alcohols having a second degree of hydrolysis range of 66%-70% and 70%-77%.

[0011] Furthermore, the mass ratio of polyvinyl alcohol in the second degree of hydrolysis range of 66%-70% and 70%-77% is 1:1-3.

[0012] Furthermore, the mass ratio of polyvinyl alcohol in the range of 66%-70% and 70%-77% second degree of hydrolysis is preferably 1:1.5-2.5, more preferably 1:2-2.5.

[0013] Furthermore, the hydrophilic contact angle of the contact lens is less than 60 degrees, preferably less than 50 degrees, and more preferably less than 40 degrees; the drug release time is 4-12 hours, preferably 6-12 hours, and most preferably 9-12 hours.

[0014] Furthermore, the drug is an ophthalmic drug molecule including but not limited to one or more of the following: cortisone, dexamethasone, prednisolone, atropine, acyclovir, ganciclovir, ancitabine, vitamin B12, tetracycline, pipemidic acid, nalidixic acid, etc.

[0015] Furthermore, the contact lens substrate is selected from hydrogel and silicone hydrogel materials.

[0016] This invention provides a method for preparing a drug-loaded contact lens, comprising the following steps:

[0017] Step 1: Add the drug to a mixed polyvinyl alcohol solution consisting of polyvinyl alcohol with a first degree of alcoholysis of 89%-95% and a second degree of alcoholysis of 66%-77%, and stir to obtain a drug-loaded polyvinyl alcohol solution.

[0018] Step 2: Apply the drug-loaded polyvinyl alcohol solution to the front and / or back surfaces of the contact lens substrate to form a drug-loaded coating on the contact lens surface;

[0019] Step 3: Use an irradiation intensity of 30-300 mW / cm² 2 The drug-loaded coating is irradiated with ultraviolet light for 10-200 minutes to cure the drug-loaded coating on the surface of the contact lens substrate.

[0020] Furthermore, the mass concentration of the polyvinyl alcohol solution is 5-12%, preferably 5-10%, and more preferably 8-10%.

[0021] Furthermore, the ultraviolet light irradiation intensity is preferably 100-250 mW / cm². 2 More preferably 150-200 mW / cm 2 .

[0022] Furthermore, the ultraviolet light irradiation time is preferably 50-180 min, more preferably 100-150 min.

[0023] The beneficial effects of this invention are as follows:

[0024] This invention utilizes the different degrees of crosslinking response of polyvinyl alcohol with different degrees of hydrolysis under ultraviolet irradiation to prepare drug-loaded contact lenses that possess both good hydrophilicity (minimum hydrophilic contact angle less than 40 degrees) and controllable drug release time (maximum 12 hours). Furthermore, the preparation method of this invention is simple and suitable for industrialization. Details are as follows.

[0025] 1. Synergistic regulation of hydrophilicity and sustained release: By utilizing the differences in UV crosslinking response of PVA with different degrees of alcoholysis, a hydrophilic contact angle of <40° (high wearing comfort) and a stable sustained release for up to 12 hours (no burst release, stable concentration) are achieved, breaking through the existing technology's problem that "comfort and sustained release cannot be achieved at the same time".

[0026] 2. The process is extremely simple and suitable for industrialization: it is completed in only three steps: solution compounding, coating and UV curing. No complicated equipment or nano-processing is required, resulting in low cost and large-scale production.

[0027] 3. High biocompatibility: Made with medical-grade polyvinyl alcohol and compliant ophthalmic drugs, it is non-irritating, has excellent biocompatibility, and is suitable for long-term wear of ocular surfaces.

[0028] 4. Wide range of applications: Compatible with hydrogel / silicone hydrogel matrices, can load a variety of ophthalmic drugs, and is suitable for the treatment of various eye diseases. Attached Figure Description

[0029] Figure 1Figure showing the hydrophilic contact angle test results of Example 1;

[0030] Figure 2 Figure 2 shows the hydrophilic contact angle test results.

[0031] Figure 3 Figure 3 shows the hydrophilic contact angle test results.

[0032] Figure 4 Figure 4 shows the results of hydrophilic contact angle testing.

[0033] Figure 5 Figure 5 shows the hydrophilic contact angle test results.

[0034] Figure 6 Figure 6 shows the hydrophilic contact angle test results.

[0035] Figure 7 Figure 7 shows the hydrophilic contact angle test results.

[0036] Figure 8 Figure 8 shows the hydrophilic contact angle test results.

[0037] Figure 9 Figure 9 shows the hydrophilic contact angle test results.

[0038] Figure 10 Figure 10 shows the results of hydrophilic contact angle testing.

[0039] Figure 11 Figure 11 showing the hydrophilic contact angle test results;

[0040] Figure 12 Figure 12 shows the results of hydrophilic contact angle testing.

[0041] Figure 13 Figure 13 shows the results of hydrophilic contact angle testing.

[0042] Figure 14 Figure 14 shows the results of hydrophilic contact angle testing.

[0043] Figure 15 Figure 15 shows the results of hydrophilic contact angle testing.

[0044] Figure 16 Figure 16 shows the results of hydrophilic contact angle testing.

[0045] Figure 17 Figure 17 shows the hydrophilic contact angle test results.

[0046] Figure 18 Figure 18 shows the hydrophilic contact angle test results.

[0047] Figure 19Graphs showing the drug sustained-release time results in Examples 1-18; Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the present invention clearer, the following description will be provided in conjunction with embodiments.

[0049] Example 1

[0050] The preparation steps of a drug-eluting contact lens are as follows:

[0051] (1) Take polyvinyl alcohol with a degree of alcoholysis of 50%, dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 3%; add pipemidic acid to the polyvinyl alcohol solution and stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%.

[0052] (2) Apply the drug-containing polyvinyl alcohol solution to the surface of the silicone hydrogel soft contact mirror.

[0053] (3) Irradiate the drug-loaded coating of the contact lens obtained in (2) with ultraviolet light with an intensity of 60mW / cm² for 10 minutes to allow the drug-loaded coating to solidify on the surface of the contact lens.

[0054] (4) The final product, drug-loaded contact lenses, is obtained by sterilizing the contact lens with moist heat.

[0055] Example 2

[0056] (1) Take polyvinyl alcohol with a degree of alcoholysis of 99%, dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 15%; add pipemidic acid to the polyvinyl alcohol solution, stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%, and then prepare drug-loaded contact lenses according to steps (2)-(4) of Example 1.

[0057] Example 3

[0058] (1) Take polyvinyl alcohol with a degree of alcoholysis of 80%, dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 5%; add pipemidic acid to the polyvinyl alcohol solution, stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%, and then prepare drug-loaded contact lenses according to steps (2)-(4) of Example 1.

[0059] Example 4

[0060] (1) Take polyvinyl alcohol with a degree of alcoholysis of 66% and 95% and dissolve it in purified water at a mass ratio of 1:1 to prepare a polyvinyl alcohol solution with a mass concentration of 5%; add pipemidic acid to the polyvinyl alcohol solution and stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%; then prepare drug-loaded contact lenses according to steps (2)-(4) of Example 1.

[0061] Example 5

[0062] (1) Take polyvinyl alcohol with a degree of alcoholysis of 75% and 89%, dissolve it in purified water at a mass ratio of 1:1 to prepare a polyvinyl alcohol solution with a mass concentration of 5%; add pipemidic acid to the polyvinyl alcohol solution and stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%, and then prepare drug-loaded contact lenses according to steps (2)-(4) of Example 1.

[0063] Example 6

[0064] (1) Take polyvinyl alcohol with a degree of alcoholysis of 75% and 89% and dissolve it in purified water at a mass ratio of 2:1 to prepare a polyvinyl alcohol solution with a mass concentration of 10%; add pipemidic acid to the polyvinyl alcohol solution and stir evenly to prepare a pipemidic acid solution with a mass ratio of 2%; then prepare drug-loaded contact lenses according to steps (2)-(4) of Example 1.

[0065] The preparation steps, hydrophilic contact angle data, and drug release times for Examples 1-6 are shown in Table 1:

[0066] Hydrophilic contact angle testing: The hydrophilic contact angle test is a commonly used surface property testing method to evaluate the hydrophilicity or hydrophobicity of solid surfaces. The contact angle meter assesses surface properties by placing a small drop of water on the test surface and measuring the contact angle at the point of contact between the water droplet and the surface. Soft contact mirrors made of silicone hydrogel before and after coating with a polyvinyl alcohol slow-release layer were tested for their water contact angles. A larger water contact angle indicates good hydrophobicity and poor hydrophilicity. A smaller water contact angle indicates good hydrophilicity. By comparing the contact angles before and after treatment, the effectiveness of the hydrophilicity improvement can be evaluated.

[0067] Drug release time-concentration detection: Piperidin has maximum absorption at a wavelength of 275 nm. Treated lenses were immersed in PBS buffer (GB / T 11417.4-2012) with a pH of 7.4±0.1 and an osmotic pressure of 310 mOsm / kg±5 mOsm / kg, under water bath shaking at a temperature of 37±1℃. The immersion solution was collected periodically, and the UV transmittance at 275 nm was measured using a UV spectrophotometer until the transmittance no longer changed; the release time could then be determined.

[0068] Table 1:

[0069]

[0070] The results of the tests on hydrophilic contact angle and drug release time show that the drug-loaded contact lenses prepared with the 50% hydrolyzed polyvinyl alcohol solution in Example 1 have poor drug release time and hydrophilic contact angle. While the drug-loaded contact lenses prepared with the 99% hydrolyzed polyvinyl alcohol solution in Example 2 have the longest drug release time, they also have the largest hydrophilic contact angle. Although the drug-loaded contact lenses prepared with the 80% hydrolyzed polyvinyl alcohol solution in Example 3 have the smallest hydrophilic contact angle and can achieve full wetting, their drug release time is too short. Therefore, the single-degree hydrolyzed PVA solutions described in Examples 1-3 cannot balance hydrophilicity and release time, resulting in either poor hydrophilicity or excessively short / long release times. The drug-loaded contact lenses prepared with polyvinyl alcohol solutions of two different degrees of hydrolysis in Examples 4-6 show a significantly reduced hydrophilic contact angle and a release time extended to 4-5 hours, achieving a balance between a longer drug release time and a smaller hydrophilic contact angle.

[0071] Example 7

[0072] After following steps (1) and (2) of Example 6, (3) the drug-loaded coating of the contact lens obtained in (2) is irradiated with ultraviolet light with an intensity of 100mW / cm² for 10 minutes to solidify the drug-loaded coating on the surface of the contact lens, and (4) the contact lens is sterilized by moist heat to obtain the final product, the drug-loaded contact lens.

[0073] Example 8

[0074] After following steps (1) and (2) of Example 6, (3) the drug-loaded coating of the contact lens obtained in (2) is irradiated with ultraviolet light with an intensity of 100mW / cm² for 10 minutes to cure the drug-loaded coating on the surface of the contact lens, and (4) the contact lens is sterilized by moist heat to obtain the final product, the drug-loaded contact lens.

[0075] Example 9

[0076] After following steps (1) and (2) of Example 6, (3) the drug-loaded coating of the contact lens obtained in (2) is irradiated with ultraviolet light with an intensity of 150mW / cm² for 60 minutes to cure the drug-loaded coating on the surface of the contact lens, and (4) the contact lens is sterilized by moist heat to obtain the final product, the drug-loaded contact lens.

[0077] Example 10

[0078] After following steps (1) and (2) of Example 6, (3) the drug-loaded coating of the contact lens obtained in (2) is irradiated with ultraviolet light with an intensity of 150mW / cm² for 150 minutes to cure the drug-loaded coating on the surface of the contact lens, and (4) the contact lens is sterilized by moist heat to obtain the final product, the drug-loaded contact lens.

[0079] The preparation steps, hydrophilic contact angle data, and drug release time of Examples 7-10 are shown in Table 2:

[0080] Table 2:

[0081]

[0082] Based on the preparation steps of polyvinyl alcohol solutions with two different degrees of hydrolysis in Example 6, Examples 7-10 set different intensities and durations of ultraviolet irradiation. From the test results of hydrophilic contact angle and drug buffer time, it can be seen that the drug release time of Examples 7-8 is longer than that of Example 6; the drug release time of Examples 9-10 is longer than that of Example 7, and the hydrophilic contact angle is smaller than that of Example 8. Therefore, it has both a smaller hydrophilic contact angle and a longer drug release time.

[0083] Example 11

[0084] (1) Take polyvinyl alcohol with a degree of alcoholysis of 77% and 95% and dissolve it in purified water at a mass ratio of 3:1 to prepare a polyvinyl alcohol solution with a mass concentration of 5%. After following step (2) in Example 1, (3) irradiate the drug-loaded coating of the contact lens obtained in (2) with ultraviolet light with an irradiation intensity of 30mW / cm² for 50 minutes to cure the drug-loaded coating on the surface of the contact lens.

[0085] (4) The final product, drug-loaded contact lenses, is obtained by sterilizing the contact lens with moist heat.

[0086] Example 12

[0087] (1) Take polyvinyl alcohol with a degree of alcoholysis of 70% and 94% and dissolve it in purified water at a mass ratio of 2.5:1 to prepare a polyvinyl alcohol solution with a mass concentration of 8%. After following step (2) in Example 1, (3) irradiate the drug-loaded coating of the contact lens obtained in (2) with ultraviolet light with an irradiation intensity of 300mW / cm² for 180min to cure the drug-loaded coating on the surface of the contact lens.

[0088] (4) The final product, drug-loaded contact lenses, is obtained by sterilizing the contact lens with moist heat.

[0089] Example 13

[0090] (1) Take polyvinyl alcohol with a degree of alcoholysis of 75% and 92% and dissolve it in purified water at a mass ratio of 1.5:1 to prepare a polyvinyl alcohol solution with a mass concentration of 12%; after following step (2) in Example 1, (3) irradiate the drug-loaded coating of the contact lens obtained in (2) with ultraviolet light with an irradiation intensity of 250mW / cm² for 120min to cure the drug-loaded coating on the surface of the contact lens.

[0091] (4) The final product, drug-loaded contact lenses, is obtained by sterilizing the contact lens with moist heat.

[0092] Example 14

[0093] (1) Take polyvinyl alcohol with a degree of alcoholysis of 70% and 92% and dissolve it in purified water at a mass ratio of 2.5:1 to prepare a polyvinyl alcohol solution with a mass concentration of 10%; after following step (2) in Example 1, (3) irradiate the drug-loaded coating of the contact lens obtained in (2) with ultraviolet light with an irradiation intensity of 200mW / cm² for 100min to cure the drug-loaded coating on the surface of the contact lens.

[0094] (4) The final product, drug-loaded contact lenses, is obtained by sterilizing the contact lens with moist heat.

[0095] The preparation steps, hydrophilic contact angle data, and drug release time of Examples 11-14 are shown in Table 3:

[0096] Table 3:

[0097]

[0098] Based on the preparation steps of polyvinyl alcohol solutions with two different combinations of alcoholysis degrees, Examples 11-14 set up different mass ratios, contents, and UV irradiation intensities of polyvinyl alcohol with different alcoholysis degrees. From the detection results of hydrophilic contact angle and drug buffer time, it can be seen that Examples 12 and 14 have longer drug release times than Examples 11 and 13, and the hydrophilic contact angle of Example 14 is smaller than that of Example 12. Therefore, the drug-loaded contact lenses obtained under the preparation conditions of Example 14 have both a smaller hydrophilic contact angle and a longer drug release time.

[0099] Example 15

[0100] (1) Take polyvinyl alcohol with a degree of alcoholysis of 66%, 70% and 89%, wherein the mass ratio of polyvinyl alcohol with a degree of alcoholysis of 66% and 70% is 1:3, and the mass ratio of the mixture of the two degrees of alcoholysis polyvinyl alcohol to the polyvinyl alcohol with a degree of alcoholysis of 89% is 3:1. Dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 10%. Prepare the final product, drug-loaded contact lenses, according to steps (2), (3) and (4) of Example 14.

[0101] Example 16

[0102] (1) Take polyvinyl alcohol with a degree of alcoholysis of 70%, 77% and 95%, wherein the mass ratio of polyvinyl alcohol with a degree of alcoholysis of 70% and 77% is 1:2.5, and the mass ratio of the mixture of the two degrees of alcoholysis polyvinyl alcohol to the polyvinyl alcohol with a degree of alcoholysis of 95% is 1.5:1. Dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 10%; and prepare the final product, drug-loaded contact lenses, according to steps (2), (3) and (4) of Example 14.

[0103] Example 17

[0104] (1) Take polyvinyl alcohol with a degree of alcoholysis of 66%, 77% and 94%, wherein the mass ratio of polyvinyl alcohol with a degree of alcoholysis of 66% and 77% is 1:1.5, and the mass ratio of the mixture of the two degrees of alcoholysis polyvinyl alcohol to the polyvinyl alcohol with a degree of alcoholysis of 94% is 2:1. Dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 10%; and prepare the final product, drug-loaded contact lenses, according to steps (2), (3) and (4) of Example 14.

[0105] Example 18

[0106] (1) Take polyvinyl alcohol with a degree of alcoholysis of 66%, 77% and 92%, wherein the mass ratio of polyvinyl alcohol with a degree of alcoholysis of 66% and 77% is 1:2, and the mass ratio of the mixture of the two degrees of alcoholysis polyvinyl alcohol to the polyvinyl alcohol with a degree of alcoholysis of 92% is 2.5:1. Dissolve it in purified water to prepare a polyvinyl alcohol solution with a mass concentration of 10%. Prepare the final product, drug-loaded contact lenses, according to steps (2), (3) and (4) of Example 14.

[0107] Table 4:

[0108]

[0109] Based on the preparation steps of polyvinyl alcohol solutions with two different degrees of alcoholysis in Example 14, and the optimal UV light intensity and time, Examples 15-18 set up variations in the mass ratio of polyvinyl alcohol solutions with one first degree of alcoholysis and two second degrees of alcoholysis. From the detection results of the hydrophilic contact angle and drug release time, it can be seen that Examples 15-18 have both a smaller hydrophilic contact angle (less than 45°) and a longer drug release time (9-12h) compared to Example 14. Therefore, the drug-loaded contact lenses prepared with polyvinyl alcohol solutions of one first degree of alcoholysis and two second degrees of alcoholysis have both a smaller hydrophilic contact angle and a longer drug release time; and Example 18 has both a smaller hydrophilic contact angle (less than 35°) and a longer drug release time (12h) compared to Examples 15-17.

[0110] The above description is only a preferred embodiment of the present invention and is 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 drug-eluting contact lens, characterized in that, The contact lens includes a contact lens substrate and a drug-loaded coating disposed on the front and / or rear surface of the substrate. The drug-loaded coating is composed of a polyvinyl alcohol film and a drug distributed therein. The polyvinyl alcohol film is composed of at least one polyvinyl alcohol having a first degree of hydrolysis of 89%-95% and at least one polyvinyl alcohol having a second degree of hydrolysis of 66%-77%, and the mass ratio of the polyvinyl alcohols corresponding to the two degree of hydrolysis ranges is 1:1-3.

2. The drug-loaded contact lens according to claim 1, characterized in that, The first degree of alcoholysis is preferably 89%-94%, more preferably 89%-92%; the second degree of alcoholysis is preferably 70%-77%, more preferably 70%-75%.

3. The drug-eluting contact lens according to claim 1, characterized in that, The mass ratio of polyvinyl alcohol in the first degree of hydrolysis range to polyvinyl alcohol in the second degree of hydrolysis range is preferably 1:1.5-2.5, more preferably 1:2-2.

5.

4. The drug-loaded contact lens according to claim 1, characterized in that, The polyvinyl alcohol film is composed of one polyvinyl alcohol having a first degree of hydrolysis range and two polyvinyl alcohols having a second degree of hydrolysis range of 66%-70% and 70%-77%.

5. The drug-loaded contact lens according to claim 4, characterized in that, The mass ratio of polyvinyl alcohol in the range of 66%-70% and 70%-77% degree of hydrolysis is 1:1-3; preferably 1:1.5-2.5, more preferably 1:2-2.

5.

6. The drug-loaded contact lens according to claim 1, characterized in that, The contact lens has a hydrophilic contact angle of less than 60 degrees, preferably less than 50 degrees, and more preferably less than 40 degrees; the drug release time is 4-12 hours, preferably 6-12 hours, and most preferably 9-12 hours.

7. The drug-eluting contact lens according to any one of claims 1-6, characterized in that, The drugs mentioned are ophthalmic drug molecules including but not limited to one or more of the following: cortisone, dexamethasone, prednisolone, atropine, acyclovir, ganciclovir, ancitabine, vitamin B12, tetracycline, pipemidic acid, nalidixic acid, etc.

8. The drug-loaded contact lens according to claim 1, characterized in that, The contact lens substrate is selected from hydrogel and silicone hydrogel materials.

9. A method for preparing a drug-loaded contact lens according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Add the drug to a mixed polyvinyl alcohol solution consisting of polyvinyl alcohol with a first degree of alcoholysis of 89%-95% and a second degree of alcoholysis of 66%-77%, and stir to obtain a drug-loaded polyvinyl alcohol solution. Step 2: Apply the drug-loaded polyvinyl alcohol solution to the front and / or back surfaces of the contact lens substrate to form a drug-loaded coating on the contact lens surface; Step 3: Use an irradiation intensity of 30-300 mW / cm² 2 The drug-loaded coating is irradiated with ultraviolet light for 10-200 minutes to cure the drug-loaded coating on the surface of the contact lens substrate.

10. The preparation method according to claim 9, characterized in that, The polyvinyl alcohol solution has a mass concentration of 5-12%, preferably 5-10%, and more preferably 8-10%; the ultraviolet light irradiation intensity is preferably 100-250 mW / cm². 2 More preferably 150-200 mW / cm 2 The ultraviolet light irradiation time is preferably 50-180 min, more preferably 100-150 min.

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