A soluble microneedle patch for UV scleral crosslinking and its preparation method

Abstract

This invention provides a soluble microneedle patch for ultraviolet light scleral crosslinking and its preparation method, belonging to the field of biomedical materials. The soluble microneedle patch for ultraviolet light scleral crosslinking comprises microneedles and a base layer, wherein the microneedles and base layer comprise polyvinyl alcohol and oxygen-carrying riboflavin liposomes. Applying the soluble microneedle patch of this invention eliminates the need for extensive incision of the bulbar conjunctiva, thereby shortening surgical time, reducing surgical damage, alleviating patient discomfort, and increasing surgical safety. Secondly, the inventors have customized the microneedle height according to different scleral thicknesses, ensuring safe and minimally invasive scleral puncture, further enhancing surgical safety. Finally, the application of the soluble microneedle patch automates riboflavin perfusion, eliminating the need for frequent manual instillation of riboflavin solution, simplifying surgical procedures, and improving surgical efficiency.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, and in particular to a soluble microneedle patch for ultraviolet light scleral crosslinking and its preparation method. Background Technology

[0002] Currently, the number of nearsighted people worldwide is constantly increasing, and the rapid increase in the incidence of myopia has attracted widespread social attention. Studies predict that by 2050, there will be nearly 1 billion people with high myopia globally. 61.7% of people with high myopia will experience serious complications, such as posterior staphyloma, myopic macular degeneration, and high myopic optic neuropathy, which involve changes in the posterior segment of the eye and may lead to the loss of best-corrected visual acuity, severely reducing their quality of life.

[0003] When there is a high risk of developing high myopia or when conventional conservative methods for controlling axial elongation are ineffective, surgical procedures such as posterior scleral reinforcement or scleral collagen cross-linking can be used to delay the progression from high myopia to pathological myopia.

[0004] Ultraviolet-riboflavin scleral collagen cross-linking is a method that effectively improves the biomechanical properties of the sclera by increasing the covalent bonds between or within scleral collagen fibers. Animal studies have confirmed its effectiveness in slowing axial elongation and delaying myopia progression. In existing techniques, the surgeon manually infiltrates the sclera with riboflavin, followed by 30 minutes of irradiation with a separate ultraviolet light device to complete the cross-linking procedure.

[0005] However, the above method requires a large area of ​​conjunctival dissection and traction of the eyeball to expose the target sclera in order to achieve an effective cross-linking range. This method is relatively complex, with large surgical incisions, long operating time, and increased risks of infection and patient discomfort. Furthermore, to achieve an effective riboflavin concentration in the sclera, the surgeon needs to manually and frequently instill riboflavin solution, wasting manpower and potentially leading to operational errors. In addition, the cross-linking process consumes a large amount of oxygen, while the oxygen content in the deep scleral tissue is low, making it difficult to achieve a good cross-linking effect. Summary of the Invention

[0006] Therefore, in order to solve these problems, the inventors designed and prepared an oxygen-carrying soluble riboflavin microneedle patch. The height of the microneedles was designed according to the scleral thickness of different myopic patients. The aim is to be able to puncture the sclera in a safe and minimally invasive manner to improve riboflavin penetration, increase the oxygen content of scleral tissue, and further improve the effect and safety of ultraviolet-riboflavin scleral cross-linking, providing a new approach to delay the progression of myopia.

[0007] The technical problem to be solved by this invention (the purpose of the invention):

[0008] 1. Reduce surgical wounds, shorten operation time, reduce surgical damage, alleviate patient discomfort, and increase surgical safety.

[0009] 2. It automates riboflavin perfusion, eliminating the need for frequent manual dripping of riboflavin solution, simplifying surgical procedures and improving surgical efficiency.

[0010] 3. Microneedle puncture of the sclera increases the scleral penetration of riboflavin, and oxygen-carrying soluble particles increase the oxygen concentration in the scleral tissue, thereby improving the effect and precision of scleral cross-linking.

[0011] Specifically, the present invention provides:

[0012] A soluble microneedle patch for ultraviolet light scleral crosslinking, the soluble microneedle patch comprising microneedles and a base layer, the microneedles and the base layer comprising polyvinyl alcohol and oxygen-carrying riboflavin liposomes.

[0013] Optionally, the oxygen-carrying riboflavin liposome includes riboflavin, oxygen, lecithin, and sterol.

[0014] Optionally, the polyvinyl alcohol has a molecular weight of 200,000 Daltons.

[0015] Optionally, the height of the microneedle body is 487±12μm, the width of the base layer is 306±10μm, and the thickness of the base layer is 51±8μm.

[0016] Optionally, the microneedle patch is circular with a diameter of 6-10 mm, preferably 7 mm.

[0017] The method for preparing the soluble microneedle patch includes:

[0018] (1) Preparation of oxygen-carrying riboflavin liposome particles: lecithin and sterol are used to prepare liposomes, the liposomes are prepared into a suspension with 1% perfluorooctane solution, riboflavin is added and the riboflavin concentration is adjusted to 0.05%-0.2%, preferably 0.1%, and oxygen is introduced;

[0019] (2) Preparation of soluble microneedle patch: Dissolve the oxygen-carrying riboflavin liposome particles prepared in step (1) in a polyvinyl alcohol solution with a mass ratio of 5%-10%, preferably 10%. Add the resulting polyvinyl alcohol solution containing oxygen-carrying riboflavin liposome particles into a microneedle mold, dry it, and demold to obtain the soluble microneedle patch.

[0020] Optionally, in step (1), the mass ratio of lecithin to sterol is 5:1;

[0021] And / or, in step (1), the weight ratio of the 1% perfluorooctane to the liposomes is 30%-80%, preferably 40%-70%, more preferably 70%.

[0022] Optionally, in step (2), the content of the oxygen-carrying riboflavin liposome particles in the polyvinyl alcohol solution containing the oxygen-carrying riboflavin liposome particles is 0.08%-1.4% by weight, preferably 0.6%-0.8% by weight.

[0023] And / or, the molecular weight of the polyvinyl alcohol is 200,000 Daltons.

[0024] The application of the soluble microneedle patch in the preparation of a kit for treating myopia.

[0025] A kit for treating myopia, the kit comprising: the soluble microneedle patch.

[0026] The present invention can achieve the following beneficial technical effects:

[0027] 1. After applying this oxygen-carrying soluble riboflavin microneedle patch, an 8mm x 10mm conjunctival sac minimally invasive incision can be made during ultraviolet-riboflavin scleral collagen cross-linking surgery to insert the riboflavin microneedle patch into the sclera of the treatment area. There is no need to cut a large area of ​​bulbar conjunctiva, thereby shortening the operation time, reducing surgical damage, alleviating patient discomfort, and increasing surgical safety.

[0028] 2. The sclera of patients with high myopia is significantly thinner, and the area of ​​scleral thinning varies among different patients. Therefore, the inventors have designed the height and size of the microneedles according to the different thicknesses and areas of scleral thinning in different eyeballs, thereby ensuring that the sclera is positioned in a safe and minimally invasive manner, increasing surgical safety, and realizing personalized surgical design.

[0029] 3. After applying this oxygen-carrying soluble riboflavin microneedle patch, the microneedles puncture the sclera to form micropores. The basal layer of the microneedles continuously dissolves and releases riboflavin liposomes. At the same time, the riboflavin liposomes enter the scleral tissue through the micropores, realizing the automation of riboflavin perfusion. It eliminates the need for frequent manual dripping of riboflavin solution, simplifies the surgical procedure, and improves surgical efficiency. Furthermore, the microneedle puncture of the sclera increases the scleral penetration of riboflavin, and the oxygen-carrying soluble particles increase the oxygen concentration in the scleral tissue, thereby improving the effect and precision of scleral cross-linking. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a microneedle patch morphology diagram provided in Embodiment 1 of the present invention;

[0032] Figure 2 The diagram shows the mechanical properties of the microneedles provided in Embodiment 1 of the present invention;

[0033] Figure 3 The image shows the effect of microneedle puncture of the sclera of a pig eye (×400) provided in Embodiment 1 of the present invention;

[0034] Figure 4 This is a scanning electron microscope image of a microneedle provided in Embodiment 2 of the present invention;

[0035] Figure 5 This is a diagram of the microneedle dissolution performance provided in Example 2 of the present invention (scale bar = 500 μm).

[0036] Figure 6 The image shows the riboflavin fluorescence analysis of porcine sclera tissue after drug administration using microneedle patches with different drug loading amounts provided in Example 2 of this invention (compared with the control group, ns = P>0.05). <0.05, <0.001, <0.0001);

[0037] Figure 7 The graph shows the tissue riboflavin concentration after administration of microneedle patches with different drug loadings to the sclera of pigs provided in Example 2 of this invention (compared with the control group, ns = P>0.05). <0.01, <0.0001);

[0038] Figure 8 This diagram illustrates the preparation and use process of the microneedle patch of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. The following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention.

[0040] Current scleral cross-linking methods require large-area separation of the bulbar conjunctiva and traction of the eyeball to expose the target sclera. This method is complex, involves large surgical wounds, is time-consuming, and significantly increases the risk of infection and patient discomfort. In contrast, when using the soluble microneedle patch of this invention for riboflavin delivery, only a small incision of about 8mm is required, reducing the surgical wound and exposure.

[0041] Currently, riboflavin is administered manually by frequently dripping a riboflavin solution onto the exposed sclera every 3 minutes, using a photosensitizer solution containing 0.1% riboflavin to ensure complete penetration of the riboflavin into the scleral matrix. After a 20-minute riboflavin soaking time, ultraviolet cross-linking begins. However, when using the soluble microneedle patch of this invention for riboflavin delivery, the microneedle patch can dissolve and release riboflavin within 5 minutes, while simultaneously penetrating rapidly into the scleral matrix through microneedle puncture, shortening the procedure time.

[0042] Example 1

[0043] 1. Preparation of oxygen-carrying riboflavin liposomes

[0044] Liposomes (LPs) were prepared by mixing lecithin and sterol at a mass ratio of 5:1. Then, 1% perfluorooctane (PFC) was mixed with the liposomes at concentrations of 40%, 50%, 60%, and 70% to form a suspension. Riboflavin (RF) was added and the concentration was adjusted to 0.1%, resulting in an RF-PFC-LP suspension. 95% oxygen was introduced into the RF-PFC-LP suspension at a flow rate of 4 L / min for 5 minutes using an oxygen generator, followed by storage at room temperature.

[0045] The concentration of riboflavin in RF-PFC-LP suspension was determined. The detection method is as follows: Equal volumes of suspensions with different concentrations were pipetted into 96-well plates and mixed with a prepared riboflavin standard curve solution (the highest concentration of 2% serially diluted 8 times). The absorbance of riboflavin was measured using a microplate reader. The linear relationship between riboflavin concentration and absorbance was determined using the riboflavin standard curve solution. The concentration of riboflavin in the suspension was calculated from the absorbance of the test solution against the standard curve.

[0046] The dissolved oxygen concentration of RF-PFC-LP was measured at 5, 10, and 15 minutes to screen liposomes with optimal oxygen-carrying and drug-loading capabilities. The detection method was as follows: A dissolved oxygen meter was used to measure the oxygen concentration of the liposome suspension after it had been allowed to stand at room temperature for a period of time. Once the temperature stabilized, 95% oxygen was introduced at a flow rate of 4 L / min for 10 minutes, and the oxygen concentration in the suspension was confirmed to be stable and no longer increasing using a dissolved oxygen meter. Subsequently, the oxygen concentration in the suspension was measured using a dissolved oxygen meter after 5, 10, and 15 minutes.

[0047] 2. Screening for riboflavin-soluble microneedle patches with optimal physicochemical properties.

[0048] Polyvinyl alcohol (PVA) of different molecular weights (~10w, ~20w) was dissolved in pure water at concentrations of 5%, 10%, and 15%. 20 mg of oxygen-carrying riboflavin liposome particles were dissolved in 10 mL of PVA solution. 0.5 mL of PVA solution was added to a polydimethylsiloxane (PDMS) mold, and the mixture was dried overnight in an oven at 37°C. After demolding, microneedle patches were obtained. The morphology of the microneedles was evaluated using a microscope.

[0049] 3. Evaluation of the mechanical properties of soluble microneedle patches with different PVA contents

[0050] Soluble microneedle patches with different PVA contents were placed in a universal testing machine, and force-displacement curves were plotted to evaluate the mechanical properties of the microneedles.

[0051] 4. Scleral penetration ability of soluble microneedle patches with different PVA contents

[0052] Soluble microneedle patches with different PVA contents were placed on the sclera of isolated pig eyes. After pressing for 5 seconds, the microneedle patches were removed. Tissue samples were taken from the pressed area, fixed, embedded, sectioned, and stained with H&E. The scleral penetration was observed under a microscope.

[0053] Experimental results:

[0054] 1. Characterization of oxygen-carrying riboflavin liposome particles:

[0055] The riboflavin content in a suspension prepared by 1% PFC and liposomes at a ratio of 40% to 70% is 0.149 mg / mL to 0.155 mg / mL, preferably a suspension prepared by 1% PFC and liposomes at a ratio of 70% (containing 0.154 ± 0.006 mg / mL of riboflavin).

[0056] A suspension of 1% PFC and liposomes at a ratio of 40% to 70% releases oxygen at a rate of 21 mg / mL to 33 mg / mL within 15 minutes, preferably a suspension of 1% PFC and liposomes at a ratio of 70% (releases oxygen at a rate of 33 ± 1 mg / mL within 15 minutes).

[0057] The results are shown in Tables 1 and 2 below:

[0058] Table 1: Riboflavin concentration in RF-PFC-LP

[0059]

[0060] Table 2: Dissolved oxygen concentration (mg / mL) of RF-PFC-LP over 15 minutes

[0061]

[0062] 2. Screening of oxygen-carrying riboflavin-soluble microneedle patches:

[0063] Experimental results are as follows Figure 1 As shown. From Figure 1 As can be seen, the inventors observed the morphology of the prepared microneedle patches under a microscope. The microneedle patches are circular with a diameter of 7 mm, and each microneedle patch contains 101 needles. When the PVA concentration is 5% and 10%, the microneedle patches have good formability. As the concentration increases to 15%, the microneedle patches shrink significantly and do not have good formability.

[0064] 3. Evaluation of the mechanical properties of oxygen-carrying riboflavin microneedle patches:

[0065] Experimental results are as follows Figure 2 As shown. From Figure 2 It can be seen that the compressive force on all four groups of microneedles increases with the increase of the microneedle tip deformation displacement. No obvious inflection point was observed in any of the different molecular weight groups, showing relatively continuous deformation. More importantly, the 20w molecular weight microneedles exhibit stronger mechanical properties than the 10w microneedles, and the microneedles prepared with 10% concentration of 20w molecular weight PVA have the best mechanical properties.

[0066] 4. Evaluation of scleral penetration ability of riboflavin microneedle patches:

[0067] Experimental results are as follows Figure 3 As shown. From Figure 3 It can be seen that the microneedle patches in the 10wPVA-5%, 10wPVA-10%, and 20wPVA-5% groups did not cause perforation of the sclera tissue in pig eyes. The 20wPVA-10% group showed obvious perforation of the surface layer of the pig sclera tissue, a result consistent with the mechanical properties of the microneedles.

[0068] Example 2

[0069] The following examples illustrate the preparation method and characterization of the soluble microneedle patch for ultraviolet scleral crosslinking according to the present invention, but the present invention is not limited thereto. Soluble microneedle patches prepared using the method of the present invention can achieve similar effects. Further details will not be elaborated here.

[0070] 1. Preparation of oxygen-carrying soluble riboflavin microneedle patches

[0071] (1) Preparation of oxygen-carrying riboflavin liposome particles: Liposomes (LP) were prepared by mixing lecithin and sterol at a mass ratio of 5:1. Then, 1% perfluorooctane (PFC) and liposomes were mixed at a concentration of 40%-70% to form a suspension. Riboflavin (RF) was added and the riboflavin concentration was adjusted to 0.05%-0.2% to prepare an RF-PFC-LP suspension. 95% oxygen was introduced into the RF-PFC-LP suspension at a flow rate of 4L / min for 5 minutes using an oxygen generator, and then the suspension was stored at room temperature.

[0072] (2) Dissolve 1g PVA (~20w) in 10mL of pure water, dissolve 20mg of oxygen-carrying riboflavin liposome particles in 10mL of 10% PVA solution, add 0.3mL of PVA solution containing oxygen-carrying riboflavin liposomes into a polydimethylsiloxane (PDMS) mold, and dry in an oven at 37℃ overnight. After demolding, oxygen-carrying soluble riboflavin microneedle patch is obtained.

[0073] 2. Characterization of oxygen-carrying soluble riboflavin microneedle patches

[0074] The microneedles were characterized by observation using scanning electron microscopy, including their morphology, height, and basal layer width. The microneedle patch is circular with a diameter of 7 mm (custom designs are available for different patients).

[0075] The dissolution performance of microneedles was evaluated using an inverted microscope. The experiment evaluating the dissolution performance involved dissolving microneedles in phosphate buffer and observing the dissolution process using an inverted microscope at different times (0s, 20s, 30s, 60s, 90s, 120s, and 5min).

[0076] 3. Scleral drug distribution in soluble microneedle patches with different drug loading capacities

[0077] Soluble microneedle patches with different drug loadings (i.e., different riboflavin contents) were placed on isolated porcine sclera. After 5 minutes, scleral tissue was harvested for drug (riboflavin) concentration determination. The detection method was as follows: Each piece of porcine sclera was weighed, cut into small pieces, and ground. The supernatant of the extracted tissue homogenate was placed in a 96-well plate and the absorbance was measured in an ELISA reader along with the riboflavin standard curve solution. The riboflavin content of the test tissue was calculated based on the riboflavin standard curve. The riboflavin concentration of each tissue piece was obtained by dividing the riboflavin content of each tissue piece by the mass of the scleral tissue.

[0078] Experimental results:

[0079] 1. Characterization of 10% PVA oxygen-carrying riboflavin microneedle patches:

[0080] Experimental results are as follows Figure 4 and Figure 5 As shown. From Figure 4It can be seen that the microneedle body is conical in shape, with a height of 487±12μm, a base width of approximately 306±10μm, and a base thickness of approximately 51±8μm. From Figure 5 It can be seen that as time goes on, the microneedle tip dissolves continuously, and the drug in the tip is released accordingly. At 120 seconds, the drug in the microneedle tip is almost completely released.

[0081] 2. Scleral drug distribution in soluble microneedle patches with different drug loading capacities:

[0082] Experimental results are as follows Figure 6 and Figure 7 As shown. From Figure 6 It can be seen that when the drug loading of microneedles is 0-4mg, the concentration of riboflavin in the sclera increases with the increase of drug loading of microneedles. When the drug loading of microneedles reaches 4mg or more, the concentration of riboflavin in the sclera reaches saturation.

[0083] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A soluble microneedle patch for ultraviolet light scleral crosslinking, the soluble microneedle patch comprising microneedle bodies and a base layer, characterized in that, The microneedle body and base layer comprise polyvinyl alcohol and oxygen-carrying riboflavin liposome particles, wherein the oxygen-carrying riboflavin liposome particles comprise riboflavin, oxygen, lecithin, and sterol. The method for preparing the soluble microneedle patch includes: (1) Preparation of oxygen-carrying riboflavin liposome particles: lecithin and sterol are used to prepare liposomes, the liposomes are prepared into a suspension with 1% perfluorooctane solution, riboflavin is added and the riboflavin concentration is adjusted to 0.05%-0.2%, and oxygen is introduced; (2) Preparation of soluble microneedle patch: Dissolve the oxygen-carrying riboflavin liposome particles prepared in step (1) in a polyvinyl alcohol solution with a mass ratio of 5%-10%, add the resulting polyvinyl alcohol solution containing oxygen-carrying riboflavin liposome particles into a microneedle mold, dry, and demold to obtain the soluble microneedle patch. In step (1), the weight ratio of the 1% perfluorooctane solution to the liposomes is 30%-80%.

2. The soluble microneedle patch according to claim 1, characterized in that, The molecular weight of the polyvinyl alcohol is 200,000 Daltons.

3. The soluble microneedle patch according to claim 1, characterized in that, The height of the microneedle body is 487±12μm, the width of the base layer is 306±10μm, and the thickness of the base layer is 51±8μm.

4. The soluble microneedle patch according to claim 1, characterized in that, The microneedle patch is circular with a diameter of 6-10 mm.

5. The soluble microneedle patch according to claim 4, characterized in that, The microneedle patch is circular with a diameter of 7mm.

6. The method for preparing the soluble microneedle patch according to any one of claims 1-5, characterized in that, include: (1) Preparation of oxygen-carrying riboflavin liposome particles: lecithin and sterol are used to prepare liposomes, the liposomes are prepared into a suspension with 1% perfluorooctane solution, riboflavin is added and the riboflavin concentration is adjusted to 0.05%-0.2%, and oxygen is introduced; (2) Preparation of soluble microneedle patch: Dissolve the oxygen-carrying riboflavin liposome particles prepared in step (1) in a polyvinyl alcohol solution with a mass ratio of 5%-10%, add the resulting polyvinyl alcohol solution containing oxygen-carrying riboflavin liposome particles into a microneedle mold, dry, and demold to obtain the soluble microneedle patch. In step (1), the weight ratio of the 1% perfluorooctane solution to the liposomes is 30%-80%.

7. The preparation method according to claim 6, characterized in that, In step (1), riboflavin is added and the riboflavin concentration is adjusted to 0.1%.

8. The preparation method according to claim 6, characterized in that, In step (1), the mass ratio of lecithin to sterol is 5:

1.

9. The preparation method according to claim 8, characterized in that, In step (1), the weight ratio of the 1% perfluorooctane solution to the liposomes is 40%-70%.

10. The preparation method according to claim 9, characterized in that, In step (1), the weight ratio of the 1% perfluorooctane solution to the liposomes is 70%.

11. The preparation method according to claim 6, characterized in that, In step (2), the content of the oxygen-carrying riboflavin liposome particles in the polyvinyl alcohol solution containing oxygen-carrying riboflavin liposome particles is 0.08%-1.4% by weight. And / or, the molecular weight of the polyvinyl alcohol is 200,000 Daltons.

12. The preparation method according to claim 11, characterized in that, In step (2), the content of oxygen-carrying riboflavin liposome particles in the polyvinyl alcohol solution containing oxygen-carrying riboflavin liposome particles is 0.6%-0.8% by weight.

13. The preparation method according to claim 6, characterized in that, In step (2), the oxygen-carrying riboflavin liposome particles prepared in step (1) are dissolved in a polyvinyl alcohol solution with a mass ratio of 10%.

14. The use of the soluble microneedle patch according to any one of claims 1-5 in the preparation of a drug for treating myopia.

15. A kit for treating myopia, characterized in that, The kit comprises: a soluble microneedle patch according to any one of claims 1-5.

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