Preparation method and application of hydrogel microneedle loaded with glutathione reservoir
By preparing hydrogel microneedles loaded with glutathione reservoirs, the problems of gastrointestinal degradation, first-pass effect and drug oxidation in glutathione delivery were solved, achieving efficient and precise transdermal delivery and improving drug delivery efficiency and safety.
Patent Information
- Application Number
- CN202511268974.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-06
- Publication Date
- 2025-12-02
AI Technical Summary
Existing glutathione delivery methods suffer from problems such as gastrointestinal degradation, first-pass effect, injection pain, and drug oxidative inactivation. Traditional microneedles result in excessively high local drug concentrations after rapid dissolution, leading to low delivery efficiency.
By using hydrogel microneedles loaded with glutathione reservoirs, and by preparing PDMS microneedle negative templates, preparing hydrogel microneedle material solutions, preparing blank hydrogel microneedles and glutathione reservoirs, the advantages of hydrogel microneedles and drug reservoirs are combined to achieve continuous high-dose drug delivery and efficient transdermal delivery.
It improves drug delivery efficiency, avoids drug degradation, enhances the success rate of skin puncture, optimizes drug release kinetics, maintains drug activity, and achieves efficient and precise percutaneous delivery.
Smart Images
Figure CN121041198A_ABST
Abstract
Description
I. Technical Field
[0001] This invention relates to the field of pharmaceutical preparations, and in particular to a method for preparing hydrogel microneedles loaded with glutathione reservoirs and their applications. II. Background Technology
[0002] Glutathione (GSH) is a tripeptide compound composed of glutamic acid, cysteine, and glycine linked by peptide bonds. It plays a crucial role in physiological processes such as liver metabolism, immune regulation, detoxification, and cell protection. Deficiency of this component is closely related to various pathological conditions, including aging, liver damage, and neurodegenerative diseases. Furthermore, glutathione can inhibit tyrosinase activity and regulate melanin synthesis pathways, thus having applications in skin whitening.
[0003] Traditional glutathione delivery methods face numerous challenges. Oral formulations are limited by severe gastrointestinal degradation and a significant first-pass effect, resulting in bioavailability of less than 10%. While injection ensures that the drug reaches the systemic circulation directly, it is accompanied by injection pain, requires high levels of expertise, and carries a potential risk of infection. Furthermore, the active thiol group (-SH) in the glutathione molecule is easily oxidized and inactivated in conventional formulations, further reducing its therapeutic efficacy.
[0004] Microneedle technology is a novel drug delivery system based on a micrometer-scale needle array, enabling painless drug administration. Hydrogel microneedles, made from swellable polymer materials, employ a unique delivery mechanism: they first penetrate the skin in a glassy state, then absorb tissue fluid, transforming into a hydrogel state and forming drug delivery channels, ultimately delivering the active ingredient precisely to the epidermal-dermal junction. This delivery method not only avoids the first-pass effect of oral administration but also significantly improves transdermal drug delivery efficiency. Currently, most microneedles used for glutathione delivery are soluble microneedles. For example, Qi Guobin et al. prepared soluble microneedles containing glutathione using hyaluronic acid. However, avoiding the problem of excessively high local drug concentrations caused by rapid dissolution of soluble microneedles, improving the safety and efficiency of drug delivery, and preparing microneedles with excellent mechanical properties and higher drug delivery efficiency are urgent technical problems to be solved. III. Summary of the Invention
[0005] In view of the above situation and to overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing hydrogel microneedles loaded with glutathione reservoirs and their application, so as to achieve more efficient drug delivery.
[0006] The technical solution provided by this invention is a method for preparing hydrogel microneedles loaded with a glutathione reservoir, specifically including the following steps:
[0007] 1) Preparation of PDMS microneedle negative template
[0008] The curing agent and PDMS precursor (Sylgard184) were mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the needles was 850 μm). The mixture was left to stand until the air bubbles generated during mixing were eliminated. It was then placed at 20–80 °C for 3–48 h to fully cure. Finally, the PDMS and microneedle positive mold were separated to obtain the PDMS microneedle negative mold.
[0009] 2) Preparation of hydrogel microneedle material solution
[0010] The hydrogel microneedle material is dissolved in ultrapure water, wherein the mass percentage of hydrogel microneedle material to ultrapure water is 20-35%: 65-80%. The solution is centrifuged to remove air bubbles and ensure the homogeneity of the hydrogel, thus obtaining the hydrogel microneedle material solution.
[0011] 3) Preparation of blank hydrogel microneedles
[0012] The hydrogel microneedle material solution prepared in step 2) is injected into the PDMS microneedle negative template prepared in step 1), centrifuged to ensure that the material solution fills the negative template, dried at 25-37℃ for 23-35h, then crosslinked at 80-130℃ for 3-24h, and demolded to obtain blank hydrogel microneedles.
[0013] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0014] Two drug storage materials were placed in a 50mL test tube at a ratio of 1:9 to 4:1. The tube was then heated in an 80℃ oven until PEG6000 melted. The liquid was then allowed to stand at 37℃. While the liquid was cooling down without solidifying, 0.015g of glutathione drug powder was quickly added in a dark environment and vortexed to promote uniform dispersion of the drug to obtain a mixture. The mixture was then poured into a mold used to make the storage tank. After cooling, the mixture was demolded to obtain the glutathione drug storage tank.
[0015] Alternatively, the two drug storage materials are dissolved together with 0.015g of glutathione powder in 1mL of ultrapure water at a ratio of 1:9 to 4:1, vortexed and mixed, and then freeze-dried and taken out intact to obtain the glutathione drug storage.
[0016] Finally, the glutathione drug reservoir is loaded onto the blank hydrogel microneedle backing plate prepared in step 3), and then coated with a backing layer to obtain the hydrogel microneedle loaded with the glutathione reservoir.
[0017] The blank hydrogel microneedles consist of one or more microneedles with a length of 50–5000 μm, which can pierce the skin's stratum corneum barrier for transdermal drug delivery.
[0018] The curing agent is silicone elastomer.
[0019] In step 2), the hydrogel microneedle material includes, but is not limited to, one or more of the following: PEG10000, PVM / MA, sodium carbonate powder, citric acid, PEG, polyvinyl alcohol, PVA, PVP and their derivatives monomer polymers or copolymers, hyaluronic acid, gelatin, dextrin, cyclodextrin derivatives, dextran, mannitol, cellulose acetate, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, microcrystalline cellulose, chondroitin, dextran, sucrose, chitosan, maltose, lactose, pullulan, sodium alginate, amylopectin, methacrylamide hyaluronic acid, polyethylene glycol diacrylate (PEGDA), etc.
[0020] In step 4), the drug storage material includes, but is not limited to, one or more of the following: PEG, PVP, PVA, poloxamer, polyethylene glycol monomethyl ether, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, microcrystalline cellulose, PCL, PLGA, PCL-PEG copolymer, PLGA-PEG copolymer, mannitol, trehalose, sucrose, lactose, glycine, sorbitol, maltitol, etc.
[0021] The application of the aforementioned hydrogel microneedles loaded with glutathione reservoirs in the preparation of transdermal drug delivery.
[0022] The beneficial technical effects of this invention are:
[0023] The hydrogel microneedles prepared in this invention, loaded with a glutathione reservoir, combine the advantages of hydrogel microneedles and drug reservoirs. The hydrogel microneedles can form tiny channels on the skin surface, promoting transdermal drug delivery and improving drug delivery efficiency. In addition, by carrying a drug reservoir, it can avoid drug degradation of glutathione caused by high-temperature cross-linking during the microneedle preparation process. The combined application of hydrogel microneedles and glutathione reservoirs overcomes the limitation of limited microneedle space, enabling continuous high-dose drug delivery with high transdermal delivery efficiency. This is an innovation in the field of transdermal delivery of glutathione. IV. Description of the attached drawings
[0024] Figure 1 This is a flowchart illustrating the preparation process of hydrogel microneedles loaded with glutathione reservoirs in this invention.
[0025] Figure 2 These are microscopic images of the blank hydrogel microneedles prepared in Examples 1 and 2 of this invention.
[0026] Figure 3 These are microscopic images of the blank hydrogel microneedles prepared in Examples 3 and 4 of this invention.
[0027] Figure 4 These are microscopic images of the blank hydrogel microneedles prepared in Examples 5 and 6 of this invention.
[0028] Figure 5 The puncture capability curves are for the blank hydrogel microneedles prepared in Examples 3 and 4 of this invention.
[0029] Figure 6 This is an image of a drug reservoir containing 20% PEG6000 prepared according to the present invention.
[0030] Figure 7 This is an image of a drug reservoir containing 30% PEG6000 prepared according to the present invention.
[0031] Figure 8 This is an image of a drug reservoir containing 40% PEG6000 prepared according to the present invention.
[0032] Figure 9 This is an image of a drug reservoir prepared according to the present invention, containing 60% PEG6000.
[0033] Figure 10 This is an image of a drug reservoir prepared according to the present invention, containing 70% PEG6000.
[0034] Figure 11 This is an image of a drug reservoir prepared according to the present invention, with a PEG6000 content of 90%.
[0035] Figure 12 This is a photograph of the PVP drug reservoir prepared in Example 7 of the present invention.
[0036] Figure 13 This is a photograph of the drug reservoir of trehalose and mannitol prepared in Example 8 of the present invention.
[0037] Figure 14 This is the in vitro release curve of the hydrogel microneedles loaded with glutathione reservoir in Example 4 of the present invention. V. Detailed Implementation Methods
[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0039] Example 1
[0040] In its specific implementation, this invention includes the following steps:
[0041] 1) Preparation of PDMS microneedle negative template
[0042] The curing agent and PDMS precursor (Sylgard184) were mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the needles contained was 850 μm). The mixture was left to stand to allow the air bubbles generated during mixing to be fully eliminated. It was then placed at 37°C for 24 hours to allow it to fully cure. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0043] 2) Preparation of hydrogel microneedle material solution
[0044] At room temperature, a 40% PVM / MA solution was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the prepared material solution. After stirring evenly, sodium carbonate powder was added and dissolved to obtain a hydrogel microneedle solution. In the hydrogel microneedle solution, the mass fraction of PVM / MA was 20%, the mass fraction of PEG10000 was 7.5%, and the mass fraction of sodium carbonate was 3%.
[0045] 3) Preparation of blank hydrogel microneedles
[0046] The hydrogel microneedle material solution prepared in step 2) was injected into the PDMS microneedle negative template prepared in step 1), centrifuged at 4000 r / min for 5 min, dried at 37℃ for 24 h, and then crosslinked in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0047] Prepared hydrogel microneedles such as Figure 2 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0048] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0049] Add PEG200 and PEG6000 to a 50mL tube, with PEG6000 accounting for 20%. First, place it at 80℃ for 15min to melt PEG6000. Remove the liquid and place it in a 37℃ environment for 1h. When it cools down but does not re-solidify, quickly add 0.015g of glutathione drug powder in a light-protected environment and vortex to promote uniform drug dispersion. Pour the mixture into a mold for making the reservoir. After cooling and solidification, demold to obtain the glutathione drug reservoir. Finally, load the reservoir onto the blank hydrogel microneedle backing plate prepared in step 3) and cover it with a backing layer to obtain the hydrogel microneedle loaded with glutathione reservoir.
[0050] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.24 g, and PEG6000 is 0.06 g. (See [link to relevant documentation]). Figure 6 .
[0051] Example 2
[0052] In its specific implementation, this invention includes the following steps:
[0053] 1) Preparation of PDMS microneedle negative template
[0054] The curing agent and PDMS precursor (Sylgard 184) were uniformly mixed at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the microneedles was 850 μm). The mixture was allowed to stand to allow any air bubbles generated during mixing to dissipate. It was then placed at 37°C for 24 hours to allow for complete curing. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0055] 2) Preparation of hydrogel microneedle material solution
[0056] At room temperature, a 40% PVM / MA solution was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the prepared material solution. After stirring evenly, sodium carbonate powder was added and dissolved to obtain a hydrogel microneedle solution. In the hydrogel microneedle solution, the mass fraction of PVM / MA was 20%, the mass fraction of PEG10000 was 7.5%, and the mass fraction of sodium carbonate was 3%.
[0057] 3) Preparation of blank hydrogel microneedles
[0058] The hydrogel microneedle material solution prepared in step 2) was injected into the PDMS microneedle negative template prepared in step 1), centrifuged at 4000 r / min for 5 min, dried at 37℃ for 24 h, and then crosslinked in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0059] Prepared hydrogel microneedles such as Figure 2 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0060] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0061] PEG200 and PEG6000 were added to a 50 mL tube, with PEG6000 accounting for 30%. The tube was first placed at 80°C for 15 min to melt the PEG6000. The liquid was then placed at 37°C for 1 h. When the liquid cooled down without re-solidifying, 0.015 g of glutathione drug powder was quickly added under light-protected conditions, and the mixture was vortexed to promote uniform dispersion of the drug. The mixture was poured into a mold for making the reservoir. After cooling and solidification, the mixture was demolded to obtain the glutathione drug reservoir. Finally, the reservoir was loaded onto the backing plate of the microneedle and covered with a backing layer to obtain the hydrogel microneedle loaded with the glutathione reservoir.
[0062] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.21 g, and PEG6000 is 0.09 g. (See [link to relevant documentation]). Figure 7 .
[0063] Example 3
[0064] In its specific implementation, this invention includes the following steps:
[0065] 1) Preparation of microneedle negative template
[0066] The curing agent and PDMS precursor (Sylgard 184) were uniformly mixed at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the microneedles was 850 μm). The mixture was allowed to stand to eliminate any air bubbles generated during mixing, and then placed at 37°C for 24 hours to allow for complete curing. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0067] 2) Preparation of hydrogel microneedle material solution
[0068] At room temperature, a PVM / MA solution with a mass fraction of 40% was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the material solution prepared above and stirred evenly. In the hydrogel microneedle material solution, the mass fraction of PVM / MA was 20% and the mass fraction of PEG10000 was 7.5%.
[0069] 3) Preparation of blank hydrogel microneedles
[0070] The above hydrogel microneedle material solution was injected into the microneedle negative template prepared in step 1), and centrifuged at 4000 r / min for 5 min. It was then dried at 37℃ for 24 h, followed by crosslinking in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0071] The hydrogel microneedles prepared according to the above embodiments are as follows: Figure 3As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and translucent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix. The puncture capability of the microneedles was characterized using a synthetic film layered structure model, such as... Figure 5 As shown, at 0.5 mm·min -1 Under puncture speed and 32N load, the microneedle prepared by this invention achieved a penetration efficiency of 94.93% in a 254μm thick film layer, proving that it has excellent puncture mechanical properties.
[0072] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0073] PEG200 and PEG6000 were added to a 50 mL tube, with PEG6000 comprising 40%. The tube was first placed at 80°C for 15 minutes to melt the PEG6000. The resulting liquid was then placed at 37°C for 1 hour. Once cooled but not re-solidified, 0.015 g of glutathione drug powder was rapidly added under light-protected conditions, and the mixture was vortexed to ensure uniform drug dispersion. The mixture was poured into a mold used to create the reservoir. After cooling and solidification, the mixture was demolded to obtain the glutathione drug reservoir. Finally, the reservoir was loaded onto the backing plate of the blank hydrogel microneedles prepared in step 3) and covered with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0074] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.18 g, and PEG6000 is 0.12 g. (See [link to relevant documentation]). Figure 8 .
[0075] Example 4
[0076] In its specific implementation, this invention includes the following steps:
[0077] 1) Preparation of PDMS microneedle negative template
[0078] The curing agent and PDMS precursor (Sylgard184) were mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the needles contained was 850 μm). The mixture was left to stand to allow the air bubbles generated during mixing to be fully eliminated. It was then placed at 37°C for 24 hours to allow it to fully cure. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0079] 2) Preparation of hydrogel microneedle material solution
[0080] At room temperature, a PVM / MA solution with a mass fraction of 40% was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the material solution prepared above and stirred evenly. In the hydrogel microneedle material solution, the mass fraction of PVM / MA was 20% and the mass fraction of PEG10000 was 7.5%.
[0081] 3) Preparation of blank hydrogel microneedles
[0082] The above hydrogel microneedle material solution was injected into the microneedle negative template prepared in step 1), and centrifuged at 4000 r / min for 5 min. It was then dried at 37℃ for 24 h, followed by crosslinking in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0083] The hydrogel microneedles prepared according to the above embodiments are as follows: Figure 3 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and translucent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix. The puncture capability of the microneedles was characterized using a synthetic film layered structure model, such as... Figure 5 As shown, at 0.5 mm·min -1 Under puncture speed and 32N load, the microneedle prepared by this invention achieved a penetration efficiency of 94.93% in a 254μm thick film layer, proving that it has excellent puncture mechanical properties.
[0084] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0085] PEG200 and PEG6000 were added to a 50 mL tube, with PEG6000 comprising 60%. The tube was first placed at 80°C for 15 min to melt the PEG6000. The resulting liquid was then placed at 37°C for 1 h. When the liquid cooled but did not re-solidify, 0.015 g of glutathione drug powder was quickly added under light-protected conditions, and the mixture was vortexed to promote uniform drug dispersion. The mixture was poured into a mold for preparing the reservoir. After cooling and solidification, the mixture was demolded to obtain the glutathione drug reservoir. Finally, the reservoir was loaded onto the backing plate of the blank hydrogel microneedles prepared in step 3) and covered with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0086] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.12 g, and PEG6000 is 0.18 g. (See [link to relevant documentation]). Figure 9 .
[0087] Example 5
[0088] In its specific implementation, this invention includes the following steps:
[0089] 1) Preparation of microneedle negative template
[0090] The curing agent and PDMS precursor (Sylgard184) were mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the needles contained was 850 μm). The mixture was left to stand to allow the air bubbles generated during mixing to be fully eliminated. The mixture was then placed at 37°C for 24 hours to allow it to fully cure. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0091] 2) Preparation of hydrogel microneedle material solution
[0092] PVA was dissolved in ultrapure water, and then PVP and citric acid were added and mixed. The mixture was stirred until homogeneous to obtain a hydrogel microneedle material solution. In the hydrogel microneedle solution, the mass fraction of PVA was 15%, the mass fraction of citric acid was 1.5%, and the mass fraction of PVP was 7.5%.
[0093] 3) Preparation of blank hydrogel microneedles
[0094] The above hydrogel microneedle material solution was injected into the PDMS microneedle negative template prepared in step 1), centrifuged at 4000 r / min for 5 min, dried at 37℃ for 24 h, and then crosslinked in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0095] The hydrogel microneedles prepared according to the above embodiments are as follows: Figure 4 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0096] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0097] PEG200 and PEG6000 were added to a 50 mL tube, with PEG6000 comprising 70%. The tube was first placed at 80°C for 15 minutes to melt the PEG6000. The resulting liquid was then placed at 37°C for 1 hour. Once cooled but not re-solidified, 0.015 g of glutathione drug powder was rapidly added under light-protected conditions, and the mixture was vortexed to ensure uniform drug dispersion. The mixture was poured into a mold used to create the reservoir. After cooling and solidification, the mixture was demolded to obtain the glutathione drug reservoir. Finally, the reservoir was loaded onto the backing plate of the blank hydrogel microneedles prepared in step 3) and covered with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0098] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.09 g, and PEG6000 is 0.21 g. (See [link to relevant documentation]). Figure 10 .
[0099] Example 6
[0100] In its specific implementation, this invention includes the following steps:
[0101] 1) Preparation of microneedle negative template
[0102] The curing agent and PDMS precursor (Sylgard 184) were uniformly mixed at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the microneedles was 850 μm). The mixture was allowed to stand to eliminate any air bubbles generated during mixing, and then placed at 37°C for 24 hours to allow for complete curing. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0103] 2) Preparation of hydrogel microneedle material solution
[0104] PVA was dissolved in ultrapure water, and then PVP and citric acid were added and mixed. The mixture was stirred until homogeneous to obtain a hydrogel microneedle material solution. In the hydrogel microneedle solution, the mass fraction of PVA was 15%, the mass fraction of citric acid was 1.5%, and the mass fraction of PVP was 7.5%.
[0105] 3) Preparation of blank hydrogel microneedles
[0106] The hydrogel microneedle material solution prepared in step 2) was injected into the PDMS microneedle negative template prepared in step 1), centrifuged at 4000 r / min for 5 min, dried at 37℃ for 24 h, and then crosslinked in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0107] Prepared hydrogel microneedles such as Figure 4 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0108] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0109] PEG200 and PEG6000 were added to a 50 mL tube, with PEG6000 comprising 90%. The tube was first placed at 80°C for 15 min to melt the PEG6000. The resulting liquid was then placed at 37°C for 1 h. When the liquid cooled but did not re-solidify, 0.015 g of glutathione drug powder was quickly added under light-protected conditions, and the mixture was vortexed to promote uniform drug dispersion. The mixture was poured into a mold for preparing the reservoir. After cooling and solidification, the mixture was demolded to obtain the glutathione drug reservoir. Finally, the reservoir was loaded onto the backing plate of the blank hydrogel microneedles prepared in step 3) and covered with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0110] The total mass of the drug reservoir prepared in this ratio is 0.315 g, of which glutathione is 0.015 g, PEG200 is 0.03 g, and PEG6000 is 0.27 g. (See [link to relevant documentation]). Figure 11 .
[0111] Example 7
[0112] In its specific implementation, this invention includes the following steps:
[0113] 1) Preparation of microneedle negative template
[0114] The curing agent and PDMS precursor (Sylgard184) were mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the needles contained was 850 μm). The mixture was left to stand to allow the air bubbles generated during mixing to be fully eliminated. The mixture was then placed at 37°C for 24 hours to allow it to fully cure. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0115] 2) Preparation of hydrogel microneedle material solution
[0116] At room temperature, a PVM / MA solution with a mass fraction of 40% was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the material solution prepared above and stirred evenly. In the hydrogel microneedle material solution, the mass fraction of PVM / MA was 20% and the mass fraction of PEG10000 was 7.5%.
[0117] 3) Preparation of blank hydrogel microneedles
[0118] The above hydrogel microneedle material solution was injected into the microneedle negative template prepared in step 1), and centrifuged at 4000 r / min for 5 min. It was then dried at 37℃ for 24 h, and then crosslinked in an oven at 80℃ for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0119] Prepared hydrogel microneedles such as Figure 3 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0120] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0121] Weigh 0.01 g of PVP into an EP tube, add 1 mL of ultrapure water, vortex for a suitable time, and after the PVP dissolves, add 0.015 g of glutathione, vortex again, and freeze the resulting solution in a -80°C freezer until no more water flows out. Then, freeze-dry for 48 hours. The glutathione reservoir formed after freeze-drying can be easily removed from the tube and remains intact. Figure 12 In use, the glutathione reservoir is loaded onto the blank hydrogel microneedles prepared in step 3), and then coated with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0122] Example 8
[0123] In its specific implementation, this invention includes the following steps:
[0124] 1) Preparation of microneedle negative template
[0125] The curing agent and PDMS precursor (Sylgard 184) were uniformly mixed at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold (the height of the microneedles was 850 μm). The mixture was allowed to stand to allow air bubbles generated during mixing to dissipate completely, and then placed at 37°C for 24 hours to allow for full curing. The PDMS and microneedle positive mold were then separated to obtain the PDMS microneedle negative mold.
[0126] 2) Preparation of hydrogel microneedle material solution
[0127] At room temperature, a PVM / MA solution with a mass fraction of 40% was prepared, stirred evenly, and stored at 4°C. PEG10000 was dissolved in ultrapure water and then mixed with the material solution prepared above and stirred evenly. In the hydrogel microneedle material solution, the mass fraction of PVM / MA was 20% and the mass fraction of PEG10000 was 7.5%.
[0128] 3) Preparation of blank hydrogel microneedles
[0129] The above hydrogel microneedle material solution was injected into the microneedle negative template prepared in step 1), and centrifuged at 4000 r / min for 5 min. It was then dried at 37℃ for 24 h, followed by crosslinking at 80℃ in an oven for 24 h. After demolding, blank hydrogel microneedles were obtained.
[0130] Prepared hydrogel microneedles such as Figure 3 As shown, the microneedle array exhibits a highly uniform conical structure with a smooth and transparent needle surface. Under an optical microscope, the needle tips are neatly arranged, forming a perfect geometric matrix.
[0131] 4) Preparation of hydrogel microneedles loaded with glutathione reservoir
[0132] Weigh 0.01 g of mannitol and 0.01 g of trehalose into an EP tube, then add 1 mL of ultrapure water. Vortex for a suitable time until fully dissolved. Add 0.015 g of glutathione, vortex again, and freeze the solution at -80°C until no more water flows out. Then freeze-dry for 48 hours. The resulting glutathione reservoir can be easily removed from the tube and remains intact. Figure 13 In use, the glutathione reservoir is loaded onto the blank hydrogel microneedles prepared in step 3), and then coated with a backing layer to obtain the hydrogel microneedles loaded with the glutathione reservoir.
[0133] The hydrogel microneedles of this invention can form tiny channels on the skin surface, promoting transdermal drug absorption, while the drug reservoir maintains glutathione in a relatively stable state within the microneedles and provides a reliable drug source when the hydrogel microneedles begin drug delivery. The combination of these two components enables more precise and efficient drug delivery, improving the transdermal delivery efficiency of glutathione. Before use, the drug reservoir is simply attached to the backing plate of the hydrogel microneedles with 10 μL of ultrapure water. In practical applications, a drug-containing formulation can also be injected into a blank microneedle, coated with a drug-containing formulation, or applied after skin treatment with microneedles. Relevant experimental data are as follows:
[0134] I. Transdermal Release of Glutathione Hydrogel Microneedles from Example 3 Using a Vertical Franz Diffusion Cell
[0135] 1. Place 0.18g of PEG200 and 0.12g of PEG6000 into a 50mL tube and place in an 80℃ oven for 15 minutes until the PEG6000 melts. Remove the liquid and place it at 37℃ for 1 hour. When it cools but does not re-solidify, quickly add 0.015g of glutathione powder under light-protected conditions and vortex as needed to promote uniform drug dispersion. Pour the mixture into a mold used to construct the reservoir, and demold after cooling and solidification. Load the reservoir onto a microneedle backing plate and cover it with a backing layer.
[0136] 2. Add 8 mL of physiological saline as the receiving solution to the receiving chamber of the Franz diffusion cell and magnetically stir at 750 rpm in a 32°C constant temperature water bath. Process isolated C57 mouse skin, trimming it to fit the shape of the Franz diffusion cell. Then, place the glutathione microneedles in the center of the mouse skin and press for 30 seconds to insert the microneedles into the skin. Place a stainless steel cylinder (16.6 mm in diameter, 12.0 g in weight) on the top of each microneedle to ensure full contact between the microneedle and the skin. Place the skin with the microneedles inserted between the supply and receiving chambers, and remove air bubbles to ensure complete contact between the receiving medium and the mouse skin. At 1, 2, 3, 4, 5, 6, 8, 10, and 24 hours, collect 200 μL of the receiving solution from the receiving chamber and add 200 μL of physiological saline to the receiving chamber. After 24 hours of application, remove the microneedles and prepare a skin homogenate from the mouse skin. Both the skin homogenate and the collected receiving fluid were centrifuged at 12000 r / min for 10 min. The supernatant was then used to determine the glutathione concentration using high-performance liquid chromatography (HPLC). The experiment was performed in triplicate. A cumulative release curve was plotted with the cumulative release amount as the ordinate and the release time as the abscissa.
[0137] 3. The drug reservoir loading capacity is approximately 15 mg, and the drug release results are as follows: Figure 14 As shown, the cumulative transdermal drug release after 24 hours was 3610.92±332.02 μg, accounting for 24.30% of the total drug. A portion of the drug was also present in the skin tissue; the skin sample contained 305.89±84.51 μg of drug, accounting for 1.95% of the total drug.
[0138] Through repeated experiments and practices, other embodiments have achieved the same or similar experimental results as the above examples, and will not be described in detail here.
[0139] Compared with existing technologies, this invention offers advantages in three main aspects: First, the hydrogel microneedles possess superior mechanical properties, enabling a higher success rate for skin puncture. Second, the gentle drug release kinetics avoid the problem of excessively high local drug concentrations caused by rapid dissolution of soluble microneedles, significantly improving the safety and efficiency of drug delivery. More importantly, this invention employs a unique stepwise preparation process of "blank microneedles + drug reservoir": the hydrogel microneedle matrix and glutathione reservoir are prepared separately, and then the drug is integrated into the microneedle system through physical loading. This innovative design not only significantly increases the drug loading capacity but also avoids the impact of high temperature or ultraviolet irradiation on glutathione activity during hydrogel cross-linking, effectively reducing drug loss during preparation and maximizing the preservation of glutathione's biological activity.
[0140] The hydrogel microneedle system of this invention employs a synergistic delivery mechanism of "microneedle channel-drug reservoir": the hydrogel microneedles first form controllable microchannels on the skin surface, significantly enhancing transdermal drug permeability; simultaneously, the independently prepared drug reservoir retains drug activity through a mild formulation process, providing a reliable drug source for continuous delivery. This innovative split design combines the advantages of physical permeation enhancement with chemical drug loading, ensuring both the mechanical properties of microneedle puncture and optimizing drug loading efficiency, ultimately achieving efficient and precise delivery of active ingredients such as glutathione. It holds promise for opening new treatment pathways in aesthetic skin rejuvenation, adjuvant treatment of liver disease, and long-term management of neurodegenerative diseases, possessing significant clinical translational value and broad market application prospects.
Claims
1. A method for preparing hydrogel microneedles loaded with a glutathione reservoir, characterized in that, Specifically, the following steps are included: 1) Preparation of PDMS microneedle negative template The curing agent and PDMS precursor are mixed uniformly at a mass ratio of 1:10 and injected into a container containing a microneedle positive mold. The mixture is left to stand until the air bubbles generated during mixing are eliminated. It is then placed at 20~80℃ for 3~48 h to fully cure. Finally, the PDMS and microneedle positive mold are separated to obtain the PDMS microneedle negative mold. 2) Preparation of hydrogel microneedle material solution The hydrogel microneedle material is dissolved in ultrapure water, wherein the mass percentage of hydrogel microneedle material to ultrapure water is 20-35%: 65-80%. The solution is centrifuged to remove air bubbles and ensure the homogeneity of the hydrogel, thus obtaining the hydrogel microneedle material solution. 3) Preparation of blank hydrogel microneedles Inject the hydrogel microneedle material solution prepared in step 2) into the PDMS microneedle negative template prepared in step 1), centrifuge to ensure that the material solution fills the negative template, dry at 25~37℃ for 23~35 h, then crosslink at 80~130℃ for 3~24 h, demold to obtain blank hydrogel microneedles. 4) Preparation of hydrogel microneedles loaded with glutathione reservoir Two drug storage materials were placed in a 50 mL test tube at a ratio of 1:9 to 4:
1. The tube was then heated in an 80°C oven until PEG6000 melted. The liquid was then allowed to stand at 37°C. While the liquid was cooling down without solidifying, 0.015 g of glutathione drug powder was quickly added in a dark environment and vortexed to promote uniform dispersion of the drug to obtain a mixture. The mixture was then poured into a mold used to make the storage tank. After cooling, the mixture was demolded to obtain the glutathione drug storage tank. Alternatively, the two drug storage materials are co-dissolved with 0.015 g of glutathione powder in 1 mL of ultrapure water at a ratio of 1:9 to 4:1, vortexed and mixed, and then freeze-dried and removed intact to obtain the glutathione drug storage. Finally, the glutathione drug reservoir is loaded onto the blank hydrogel microneedle backing plate prepared in step 3), and then coated with a backing layer to obtain the hydrogel microneedle loaded with the glutathione reservoir.
2. The method for preparing hydrogel microneedles loaded with a glutathione reservoir according to claim 1, characterized in that, The blank hydrogel microneedles consist of one or more microneedles with a length of 50 to 5000 µm, which can pierce the skin's stratum corneum barrier for transdermal drug delivery.
3. The method for preparing hydrogel microneedles loaded with a glutathione reservoir according to claim 1, characterized in that, The curing agent is silicone elastomer.
4. The method for preparing hydrogel microneedles loaded with a glutathione reservoir according to claim 1, characterized in that, In step 2), the hydrogel microneedle material is one or more of the following: PEG10000, PVM / MA, sodium carbonate powder, citric acid, PEG, polyvinyl alcohol, PVA, PVP and their derivatives monomer polymers or copolymers, hyaluronic acid, gelatin, dextrin, cyclodextrin derivatives, dextran, mannitol, cellulose acetate, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, microcrystalline cellulose, chondroitin, dextran, sucrose, chitosan, maltose, lactose, pullulan, sodium alginate, amylopectin, methacrylamide hyaluronic acid, and polyethylene glycol diacrylate.
5. The method for preparing hydrogel microneedles loaded with a glutathione reservoir according to claim 1, characterized in that, In step 4), the drug reservoir material is one or more of the following: PEG, PVP, PVA, poloxamer, polyethylene glycol monomethyl ether, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, microcrystalline cellulose, PCL, PLGA, PCL-PEG copolymer, PLGA-PEG copolymer, mannitol, trehalose, sucrose, lactose, glycine, sorbitol, and maltitol.
6. The use of the hydrogel microneedles loaded with glutathione reservoir prepared by any one of claims 1-5 in the preparation of transdermal drugs.