Transdermal delivery system for nanodrug, preparation method therefor, and use thereof

Abstract

Provided are a transdermal delivery system for nanodrug, a preparation method therefor, and use thereof. In the described transdermal delivery system for nanodrug, lipoic acid is used as a drug carrier to encapsulate a chemotherapeutic drug and / or a photodynamic agent, and nanoparticles containing 1,2-dithiolane are formed by means of self-assembly. For the first time, lipoic acid is used as a carrier-assisted small molecule in the transdermal delivery system, which eliminates the need for an additional transdermal penetration enhancer. The system is not restricted by the location of the skin or the number of appendages, and does not require the assistance of devices for drug administration, but only simple application to achieve efficient transdermal penetration. The drug administration method is non-invasive, allowing for efficient transdermal penetration without disrupting the stratum corneum, thereby reducing the risk of skin infection. The depth of transdermal penetration can reach 1 mm or more, making the system suitable for both superficial and deep skin diseases. The system can be operated independently, significantly reducing costs and providing high safety. On the basis of this, the type of drug to be loaded can be flexibly changed according to the type of skin disease, enabling more precise treatment.

Description

A nano drug transdermal delivery system and its preparation method and application

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 9, 2023, with application number 2023114899017 and invention name “A nano drug transdermal delivery system, its preparation method and application”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the field of pharmaceutical technology, and in particular to a nano drug transdermal delivery system and a preparation method and application thereof. Background Art

[0003] As the largest organ in the human body, the skin performs numerous functions, such as regulating body temperature, preventing water and salt loss, and defending against invasion by various pathogens, microorganisms, and viruses. The skin is structured in two layers: the outermost epidermis and the inner dermis. Each layer of the skin is subject to endogenous genetic regulation and various exogenous stimuli, such as gene mutations, ultraviolet radiation, and trauma, which can lead to a variety of diseases. These diseases, such as scarring, psoriasis, and scarring, can severely reduce people's quality of life. Some, such as basal cell carcinoma, squamous cell carcinoma, and melanoma, can even be life-threatening. Therefore, the development of effective treatments to improve the efficacy of skin disease treatment is crucial.

[0004] Drug delivery through the skin has many advantages, including increasing patient compliance, avoiding the first-pass effect of oral medications on the liver, achieving long-term controlled release of drugs, and reducing the need for multiple doses.

[0005] Despite the unique advantages of transdermal drug delivery, most drugs are unable to effectively penetrate the dense stratum corneum, the outermost layer of the skin. Transdermal formulations generally require a molecular weight of less than 500 Da, otherwise they have difficulty penetrating the stratum corneum. A solubility greater than 1 mg / mL and an absolute oil-water partition coefficient of 1-2 are essential to ensure that the drug can both penetrate the stratum corneum and reach the viable epidermis. Due to these limitations, the types of drugs suitable for transdermal drug delivery are extremely limited.

[0006] Nanodrug delivery systems, due to their unique physicochemical properties, have been widely reported in the field of transdermal drug delivery. Compared with other transdermal drug delivery systems (TDDS), nanodrugs generally exhibit better drug release, deeper drug penetration, and allow encapsulation of both hydrophilic and hydrophobic drug molecules. Effective transdermal delivery of nanodrugs generally occurs through three pathways: the intercellular lipid pathway, the transcellular pathway, and the hair follicle pathway. Lipid-soluble and amphiphilic molecules typically penetrate the intercellular lipid pathway, but this pathway has low permeability and requires the addition of permeation enhancers to improve transdermal delivery efficiency. This can irritate the skin and lead to allergies, inflammation, and other conditions. The transcellular pathway requires nanodrugs to alternate between hydrophilic (inside the cell) and lipophilic (extracellular matrix) regions. Due to the continuous diffusion and distribution between these regions, this pathway is unfavorable for most drugs. Nanodrugs can also penetrate through skin appendages such as hair follicles, sebaceous glands, and sweat glands. However, these skin appendages only account for 0.1%-1% of the skin's surface area, limiting delivery efficiency. In addition, the density of skin appendages varies in different skin regions, limiting the application sites for transdermal delivery of nanomedicines, which reduces the types of diseases that can be treated.

[0007] Therefore, developing a new and efficient transdermal drug administration route and a non-invasive transdermal delivery system that is safe and not affected by the physicochemical properties of the drug and the skin condition has important practical significance for clinical treatment.

[0008] Summary of the Invention

[0009] In view of this, the technical problem to be solved by the present invention is to provide a nano drug transdermal delivery system and its preparation method and application, wherein the nano drug can deliver drugs through the thiol exchange pathway for single treatment or combined treatment of skin diseases.

[0010] To achieve the above object, the present invention provides the use of lipoic acid as a transdermal nano drug carrier.

[0011] The structure of lipoic acid is as follows:

[0012] The lipoic acid selected in the present invention is a racemate, and its specific stereo conformation is not limited.

[0013] As a natural coenzyme, lipoic acid participates in human metabolism and possesses a 1,2-dithiolane ring, offering both biosafety and thiol exchange potential, addressing the toxicity of current delivery vehicles. This invention utilizes lipoic acid as a drug carrier for chemotherapy drugs and / or photodynamic agents. This nanomedicine can deliver drugs via a thiol exchange pathway for the sole or combined treatment of skin diseases, representing a novel approach distinct from existing transdermal approaches.

[0014] Specifically, the present invention provides a nano drug transdermal delivery system, which uses lipoic acid as a drug carrier, encapsulates chemotherapy drugs and / or photodynamic agents, and forms nanoparticles containing 1,2-dithiolane through self-assembly.

[0015] The invention can encapsulate any one of chemotherapy drugs and photodynamic drugs to assemble into nanoparticles, or can encapsulate chemotherapy drugs and photodynamic agents to assemble into nanoparticles at the same time.

[0016] Optionally, the molar ratio of lipoic acid to chemotherapy drugs or photodynamic agents is 5:1-50:1.

[0017] Optionally, the molar ratio of lipoic acid to chemotherapy drugs and photodynamic agents is 5:1:1-50:1:1.

[0018] This ratio allows for optimal assembly results.

[0019] Optionally, the chemotherapy drug is a hydrophobic chemotherapy drug, more preferably a first-line chemotherapy drug for the treatment of skin cancer, including but not limited to one or more of trametinib, dabrafenib, paclitaxel, doxorubicin, docetaxel, methotrexate, vemurafenib, cobimetinib, gemcitabine, etc. The structural formula is shown below:

[0020] Optionally, the photodynamic agent is a porphyrin derivative, including but not limited to one or more of chlorin e6, hematoporphyrin monomethyl ether, etc. The structural formula is as follows:

[0021] The present invention continuously adjusts the molar ratio of lipoic acid to drug assembly according to the properties of the drug, thereby obtaining nanoparticles with uniform particle sizes. Optionally, the particle size of the nanoparticles is 10-1000 nm, preferably 50-500 nm.

[0022] The present invention has no particular limitation on the ratio of the entrapped chemotherapy drug and the photodynamic agent, which can be adjusted according to the focus and effect of the treatment. In some specific embodiments, the molar ratio of the chemotherapy drug to the photodynamic agent is 1:1.

[0023] The present invention can achieve assembly with multiple drugs by adjusting the assembly molar number of lipoic acid, and can flexibly adjust the type of drug according to the target of treatment. The self-assembled nano drug shows tolerance to GSH concentration and time, solving the problem that the current thiol exchange system is difficult to carry out multi-layer delivery due to its easy depolymerization by GSH. At the same time, the thiol exchange of the above-mentioned nano drug transdermal delivery system is through dynamic disulfide exchange transdermalization with the sulfhydryl groups on the skin surface, i.e., thiol exchange. The transdermal efficiency is not affected by the physicochemical properties (size, shape, charge, etc.) of the nano drug itself, providing a new transdermal delivery route. The test results show that the above-mentioned nano drug transdermal delivery system provided by the present invention has excellent transdermal ability and can reach subcutaneous> 1200 microns. Thanks to the excellent transdermal ability, the above-mentioned nano drug transdermal delivery system has achieved the complete eradication of melanoma. The complete eradication of this disease is almost impossible to achieve by other methods except surgical resection.

[0024] The present invention also provides a method for preparing the above-mentioned nano drug transdermal delivery system, comprising the following steps:

[0025] The lipoic acid solution and the solution containing chemotherapy drugs and / or photodynamic agents are mixed in water and self-assembled to obtain nanoparticles containing 1,2-dithiolane.

[0026] Optionally, the solvent of the lipoic acid solution is DMSO.

[0027] Optionally, the solvent in the solution containing the chemotherapy drug and / or photodynamic agent is DMSO.

[0028] Optionally, the concentration of the lipoic acid solution is 74 μg / mL-740 μg / mL.

[0029] Optionally, in the solution containing chemotherapy drugs and / or photodynamic agents, the total concentration of chemotherapy drugs and / or photodynamic agents is 5.86 μg / mL-293 μg / mL.

[0030] The present invention also provides a transdermal nano drug composition, comprising the above-mentioned nano drug transdermal delivery system and a pharmaceutically acceptable adjuvant.

[0031] The present invention has no particular limitation on the types of the above-mentioned adjuvants, which can be adjusted according to the dosage form.

[0032] The present invention has no particular limitation on the dosage form of the above-mentioned composition, and it can be a conventional dosage form well known in the art, including but not limited to gel, dressing, spray, patch, cream, etc.

[0033] The present invention provides the use of the above-mentioned nano drug transdermal delivery system or the above-mentioned transdermal nano drug composition in the preparation of drugs for preventing, alleviating or treating skin diseases.

[0034] The above-mentioned skin diseases include but are not limited to melanoma, psoriasis, basal carcinoma, squamous cell carcinoma, etc.

[0035] The nano drug transdermal delivery system or transdermal nano drug composition provided by the present invention can deliver drugs that are difficult to penetrate through the skin surface to the subcutaneous layer in a simple, non-invasive topical administration method (such as smearing or spraying on the skin surface) to the subcutaneous layer, reaching the lesions located in the dermis without the need for additional assistance. Not only is administration convenient, but transdermal administration can also reduce the toxic and side effects of chemotherapy drugs caused by systemic administration. Nanoparticles can penetrate into the subcutaneous dermis and achieve complete elimination of subcutaneous tumors.

[0036] The nano drug transdermal delivery system or the transdermal nano drug composition can be used for single treatment or combined treatment of skin diseases.

[0037] In combination therapy, it can be used in combination with photodynamic agents.

[0038] In some specific embodiments, while administering the aforementioned nanomedicine transdermal delivery system or the aforementioned transdermal nanomedicine composition, the affected area is also subjected to appropriate laser irradiation.

[0039] Compared to existing technologies, this invention provides a nanoparticle transdermal drug delivery system that uses lipoic acid as a drug carrier, encapsulating chemotherapy drugs and / or photodynamic agents, and self-assembling to form 1,2-dithiolane-containing nanoparticles. This invention is the first to use lipoic acid as a carrier-assisted small molecule in a transdermal delivery system.

[0040] In order to achieve efficient transdermal delivery through thiol exchange, nanomedicines need to break through the stratum corneum barrier and the cell barrier. There is a dynamic balance between sulfhydryl groups and disulfide bonds on the surface of the stratum corneum, which provides a theoretical basis for the application of the thiol exchange pathway to transdermal delivery. When a system that delivers drugs through the thiol exchange pathway is taken up by cells, the disulfide bonds in its carrier will be reduced and depolymerized by glutathione (GSH) reductase in the cytoplasm, thereby releasing the loaded drug to achieve the therapeutic purpose. However, after being depolymerized by GSH, the system loses the ability to continue delivering the drug to the next cell, which greatly limits the application of thiol exchange in drug delivery in multi-layer tissues. In particular, in some diseased tissues, such as tumor tissue, the concentration of GSH will increase significantly, and the depolymerization of the above-mentioned delivery system will also be accelerated. The present invention uses lipoic acid as a carrier. The prepared nanomedicine is incubated with GSH at a concentration of 10mM (the GSH concentration in general cancer tissue is 2-10mM, 2-10 times higher than that in normal tissue) for 4 hours before complete depolymerization. The GSH concentration in normal tissue cells is generally 1-3mM. At this concentration, the nanomedicine provided by the present invention hardly depolymerizes. Therefore, the nanomedicine can maintain its integrity during the process of penetrating the stratum corneum, epidermis, and dermis, achieving delivery of multi-layer skin tissue. When subcutaneous lesions occur, the GSH concentration at the disease site increases. At this time, the above-mentioned nanomedicine will continue to release the drug over time after passing through the stratum corneum and reaching the disease site. This achieves penetration of multiple layers of cells, overcoming the problem that drug delivery can only reach a single layer of cells.

[0041] In summary, the present invention provides a transdermal delivery system containing 1,2-dithiolane, which efficiently delivers chemotherapeutic drugs and photodynamic agents through a thiol exchange pathway. Unlike other existing transdermal routes, the thiol exchange pathway achieves transdermal penetration through dynamic disulfide exchange between a disulfide-bonded cargo and sulfhydryl groups on the skin surface. It does not require the addition of additional transdermal penetration enhancers and is not controlled by skin location or the number of appendages. No device is required for drug delivery; effective transdermal delivery can be achieved through simple application. The drug delivery method is non-invasive and can achieve efficient transdermal delivery without destroying the stratum corneum, reducing the risk of skin infection. The transdermal depth can reach over 1 mm, which is much greater than the combined thickness of the human stratum corneum (approximately 18.4 microns) and epidermis (approximately 49.5 microns). This indicates that it is not only suitable for superficial skin diseases (disease sites in the epidermis) but also has potential therapeutic effects for deeper skin diseases (disease sites in the dermis). It can be operated autonomously, significantly reducing costs. In the present invention, lipoic acid, a naturally occurring coenzyme, is used as a carrier to assist transdermal delivery. It can be used in drug assembly without modification and has high safety. Based on this, the present invention can flexibly change the type of medicine to be loaded according to the type of skin disease to achieve more accurate treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a characterization diagram of self-assembled nanoparticles of lipoic acid and chlorin e6;

[0043] FIG2 is a characterization diagram of self-assembled nanoparticles of lipoic acid and various chemotherapy drugs;

[0044] FIG3 is a characterization diagram of self-assembled nanoparticles of lipoic acid, various chemotherapy drugs, and photodynamic agents;

[0045] FIG4 is a graph showing the tolerance of Sup-TDDS (assembled of lipoic acid, trametinib and chlorin) to time at the same concentration of GSH;

[0046] FIG5 is a graph showing the tolerance of Sup-TDDS (lipoic acid, trametinib and chlorin assembly) to different GSH concentrations at the same time;

[0047] FIG6 is a graph showing the results of Sup-TDDS (lipoic acid, dabrafenib and chlorin assembly) effectively penetrating pig skin;

[0048] FIG7 is a graph showing the results of Sup-TDDS (lipoic acid, trametinib and chlorin assembly) effectively penetrating pig skin;

[0049] FIG8 is a graph showing the results of Sup-TDDS (lipoic acid, trametinib and hematoporphyrin monomethyl ether) effectively penetrating pig skin;

[0050] FIG9 is a graph showing the results of Sup-TDDS (lipoic acid and chlorin assembly) effectively penetrating pig skin;

[0051] FIG10 is a graph showing the results of Sup-TDDS (lipoic acid, trametinib and chlorin assembly) effectively penetrating rat skin;

[0052] FIG11 is a diagram showing the transdermal mechanism of Sup-TDDS (lipoic acid, trametinib and chlorin assembly);

[0053] FIG12 is a graph showing the results of tumor treatment after transdermal administration of Sup-TDDS (lipoic acid, trametinib and chlorin assembly);

[0054] FIG13 shows the expression of phosphorylated extracellular regulated protein kinase (p-ERK) in tumor tissues after transdermal treatment with Sup-TDDS (lipoic acid, trametinib, and chlorin);

[0055] FIG14 shows the expression of cadherin (CRT) and cytotoxic T cells (CD4+CD8+ T cells) in tumor tissues and the expression of mature dendritic cells (CD80+CD86+) in tumor-draining lymph nodes after transdermal treatment with Sup-TDDS (lipoic acid, trametinib, and chlorin);

[0056] FIG15 is a graph showing the results of tumor treatment after transdermal administration of Sup-TDDS (lipoic acid, dabrafenib and chlorin assembly);

[0057] FIG16 is a hematoxylin and eosin (H&E) staining image of mouse skin on the tenth day after the first transdermal administration of Sup-TDDS (lipoic acid, trametinib and chlorin assembly);

[0058] FIG17 is a graph showing the results of tumor treatment after transdermal or tail vein administration of Sup-TDDS (lipoic acid, trametinib and chlorin assembly);

[0059] FIG18 shows the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum after four days of transdermal or injection administration of Sup-TDDS (lipoic acid, trametinib, and chlorin) at a five-fold increase in drug dose;

[0060] FIG19 shows the results of H&E sections of the liver after the drug dose of Sup-TDDS (lipoic acid, trametinib and chlorin assembly) was increased fivefold. DETAILED DESCRIPTION

[0061] To further illustrate the present invention, the nano drug transdermal delivery system provided by the present invention and its application in the treatment of skin diseases are described in detail below with reference to the examples. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements, and equivalent substitutions made within the scope of the principles of the present invention should be included within the scope of protection of the present invention.

[0062] In the following examples, raw materials and reagents not otherwise specified are all commercially available standards.

[0063] Example 1 Assembly of lipoic acid and photodynamic reagent

[0064] Self-assembly of lipoic acid and chlorin

[0065] Ⅰ) Preparation of drug stock solution

[0066] Lipoic acid was prepared into a 50 mg / mL DMSO solution; dihydrochlorin was prepared into a 10 mg / mL DMSO solution;

[0067] II) Preparation of nanoparticles

[0068] Combine the components in step (I) in a 48:1 molar ratio (lipoic acid:chlorin) in a centrifuge tube and vortex to mix thoroughly. Add the mixture dropwise to deionized water while stirring. After stirring for 6 hours, dialyze for 48 hours, and centrifuge at 8000 rpm for 25 minutes, the resulting precipitate is the prepared nanoparticles with an average particle size of 142 nm. Figure 1 shows a characterization of the self-assembled nanoparticles of lipoic acid and chlorin e6. The left image is a photograph of the assembled nanoparticles, the middle image is a plot of the nanoparticle size distribution obtained using a dynamic light scattering particle size analyzer, and the right image is a transmission electron microscopy image of the nanoparticles.

[0069] Example 2 Assembly of lipoic acid and chemotherapeutic drugs

[0070] 2.1 Self-assembly of lipoic acid and cobimetinib

[0071] Ⅰ) Preparation of drug stock solution

[0072] Lipoic acid was prepared into a 50 mg / mL DMSO solution; cobimetinib was prepared into a 10 mM DMSO solution;

[0073] II) Preparation of nanoparticles

[0074] The components in step (I) were prepared at a molar ratio (lipoic acid: cobimetinib) of 50:1. Cobimetinib was first added to water and thoroughly mixed. The lipoic acid solution was added dropwise while shaking on an oscillator at 25°C and 750 rpm for 12 hours. The resulting precipitate was the prepared nanoparticles, with an average particle size of approximately 200 nm, as shown in Figure 2(a). In Figure 2(a), the left image shows the appearance of the assembled nanoparticles, the middle image shows the particle size distribution of the nanoparticles measured using a dynamic light scattering particle size analyzer, and the right image shows the morphology of the nanoparticles captured under a transmission electron microscope.

[0075] 2.2 Self-assembly of lipoic acid and trametinib

[0076] Ⅰ) Preparation of drug stock solution

[0077] Lipoic acid was prepared into a 50 mg / mL DMSO solution; trametinib was prepared into a 10 mM DMSO solution;

[0078] II) Preparation of nanoparticles

[0079] The components in step (I) were combined in a centrifuge tube at a molar ratio of 50:1 (lipoic acid: trametinib) and vortexed to mix thoroughly. The mixture was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8,000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 500 nm. This is shown in Figure 2(b). The left image shows a photograph of the assembled nanoparticles, the middle image shows the particle size distribution of the nanoparticles as measured by dynamic light scattering (DLS) particle size analysis, and the right image shows the nanoparticle morphology captured by transmission electron microscopy.

[0080] 2.3 Self-assembly of lipoic acid and gemcitabine

[0081] Ⅰ) Preparation of drug stock solution

[0082] Lipoic acid: 50 mg / mL (DMSO solution)

[0083] Gemcitabine: 10 mg / mL (DMSO solution)

[0084] II) Preparation of nanoparticles

[0085] According to the molar ratio (lipoic acid: gemcitabine) of 35:1, the components in (I) were mixed in a centrifuge tube and then quickly injected into vigorously stirred water to obtain nanoparticles with an average particle size of about 200 nm, as shown in Figure 2 c. In Figure c, the left picture is a photo of the appearance of the assembled nanoparticles, the middle picture is a particle size distribution diagram of the nanoparticles obtained by dynamic light scattering particle size analyzer testing, and the right picture is a morphology of the nanoparticles taken under a transmission electron microscope.

[0086] 2.4 Self-assembly of lipoic acid and methotrexate

[0087] Ⅰ) Preparation of drug stock solution

[0088] Lipoic acid was prepared into a 50 mg / mL DMSO solution; methotrexate was prepared into a 10 mM DMSO solution;

[0089] II) Preparation of nanoparticles

[0090] The components in (I) were prepared at a molar ratio (lipoic acid:methotrexate) of 50:1. Methotrexate was first added to water and thoroughly mixed. The lipoic acid solution was added dropwise while shaking on an oscillator at 25°C and 750 rpm for 12 hours. The resulting precipitate was the prepared nanoparticles with an average particle size of approximately 200 nm, as shown in Figure 2(d). In Figure 2(d), the left figure is a photograph of the assembled nanoparticles, the middle figure is a particle size distribution diagram of the nanoparticles obtained by dynamic light scattering particle size analysis, and the right figure is a morphology of the nanoparticles taken under a transmission electron microscope.

[0091] Examples 1 and 2 show that lipoic acid can be assembled into nanoparticles with chemotherapeutic drugs or photodynamic agents.

[0092] Example 3 Self-assembly of lipoic acid, chemotherapy drugs and photodynamic agents

[0093] 3.1 Self-assembly of lipoic acid, dabrafenib, and chlorin

[0094] Ⅰ) Preparation of drug stock solution

[0095] Lipoic acid was prepared into a 50 mg / mL DMSO solution; dabrafenib was prepared into a 10 mg / mL DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0096] II) Preparation of nanoparticles

[0097] The stock solutions of the components in step (I) were prepared in a centrifuge tube at a molar ratio of 5:1:1 (lipoic acid: dabrafenib: dihydrochlorin). The stock solutions were vortexed to mix thoroughly. The solution was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles. The average particle size was 144 nm. As shown in Figure 3(a), the left image shows a photograph of the assembled nanoparticles, the middle image shows the nanoparticle size distribution obtained using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0098] 3.2 Self-assembly of lipoic acid, trametinib, and chlorin

[0099] Ⅰ) Preparation of drug stock solution

[0100] Lipoic acid was prepared into a 50 mg / mL DMSO solution; trametinib was prepared into a 10 mM DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0101] II) Preparation of nanoparticles

[0102] The stock solutions of the components in step (I) were prepared in a centrifuge tube at a molar ratio of 14:1:2 (lipoic acid: trametinib: dihydrochlorin). The stock solutions were vortexed and thoroughly mixed. The solution was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 163 nm. As shown in Figure 3(b), the left image shows a photograph of the assembled nanoparticles, the middle image shows the nanoparticle size distribution obtained using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0103] 3.3 Self-assembly of lipoic acid, vemurafenib, and chlorin

[0104] Ⅰ) Preparation of drug stock solution

[0105] Lipoic acid was prepared into a 50 mg / mL DMSO solution; vemurafenib was prepared into a 10 mM DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0106] II) Preparation of nanoparticles

[0107] The stock solutions of the components in step (I) were prepared in a centrifuge tube at a molar ratio of 14:1:2 (lipoic acid: vemurafenib: dihydrochlorin). The stock solutions were vortexed and thoroughly mixed. The solution was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 132 nm. As shown in Figure 3 (c), the left image shows the appearance of the assembled nanoparticles, the middle image shows the particle size distribution of the nanoparticles measured using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0108] 3.4 Self-assembly of lipoic acid, docetaxel, and chlorin

[0109] Ⅰ) Preparation of drug stock solution

[0110] Lipoic acid was prepared into a 50 mg / mL DMSO solution; docetaxel was prepared into a 10 mM DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0111] II) Preparation of nanoparticles

[0112] The stock solutions of the components in step (I) were prepared in a centrifuge tube at a molar ratio of 14:1:2 (lipoic acid:docetaxel:chlorin). The stock solutions were vortexed and thoroughly mixed. The solution was added dropwise to deionized water while stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 148 nm. As shown in Figure 3 (d), the left image shows the appearance of the assembled nanoparticles, the middle image shows the nanoparticle size distribution obtained by dynamic light scattering particle size analysis, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0113] 3.5 Self-assembly of lipoic acid, paclitaxel, and chlorin

[0114] Ⅰ) Preparation of drug stock solution

[0115] Lipoic acid was prepared into a 50 mg / mL DMSO solution; paclitaxel was prepared into a 10 mM DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0116] II) Preparation of nanoparticles

[0117] The components in step (I) were placed in a centrifuge tube at a molar ratio of 14:1:2 (lipoic acid:paclitaxel:chlorin). Vortex and mix thoroughly. The mixture was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 142 nm. As shown in Figure 3(e), the left image shows the appearance of the assembled nanoparticles, the middle image shows the particle size distribution of the nanoparticles measured using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0118] 3.6 Self-assembly of lipoic acid, doxorubicin, and chlorin e6

[0119] Ⅰ) Preparation of drug stock solution

[0120] Lipoic acid was prepared into a 50 mg / mL DMSO solution; doxorubicin was prepared into a 10 mg / mL DMSO solution; and chlorin was prepared into a 10 mg / mL DMSO solution.

[0121] II) Preparation of nanoparticles

[0122] The components in step (I) were placed in a centrifuge tube at a molar ratio of 29:1:1 (lipoic acid: doxorubicin: hematoporphyrin monomethyl ether). Vortex and mix thoroughly. The mixture was added dropwise to deionized water with stirring. After stirring for 6 hours, the mixture was dialyzed for 48 hours and centrifuged at 8000 rpm for 25 minutes. The resulting precipitate was the prepared nanoparticles with an average particle size of 807 nm. As shown in Figure 3(f), the left image shows the appearance of the assembled nanoparticles, the middle image shows the particle size distribution of the nanoparticles measured using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0123] 3.7 Self-assembly of lipoic acid, trametinib, and hematoporphyrin monomethyl ether

[0124] Ⅰ) Preparation of drug stock solution

[0125] Lipoic acid was prepared into a 50 mg / mL DMSO solution; trametinib was prepared into a 10 mM DMSO solution; and hematoporphyrin monomethyl ether was prepared into a 10 mM DMSO solution.

[0126] II) Preparation of nanoparticles

[0127] The components in step (I) were placed in a centrifuge tube at a molar ratio of 48:1:1 (lipoic acid: trametinib: hematoporphyrin monomethyl ether). Vortex and mix thoroughly. The mixture was added dropwise to deionized water with stirring for 6 hours, followed by 48 hours of dialysis and 25 minutes of centrifugation at 8000 rpm. The resulting precipitate was the prepared nanoparticles with an average particle size of 142 nm. As shown in Figure 3 (g), the left image shows a photograph of the assembled nanoparticles, the middle image shows the nanoparticle size distribution obtained using a dynamic light scattering particle size analyzer, and the right image shows the nanoparticle morphology captured under a transmission electron microscope.

[0128] Example 3 shows that lipoic acid can be assembled into nanoparticles together with various chemotherapeutic drugs and photodynamic agents.

[0129] Example 4: Nanoparticles assembled from lipoic acid and multiple drugs have GSH tolerance

[0130] Ⅰ) Preparation of 100 mM GSH aqueous solution

[0131] II) Nanoparticles were incubated with 10 mM GSH for different time periods

[0132] Four tubes of the nanoparticles described in Example 3.2 containing 10 mM GSH were placed in a shaker at 37° C. and incubated for 0.5 h, 1 h, 2 h, and 4 h, respectively, and then photographed for appearance.

[0133] Since chemotherapy drugs and dihydrochlorins are extremely hydrophobic, the five-membered disulfide ring of lipoic acid in the nanomedicine is gradually reduced over time, the nanomedicine gradually disaggregates and releases the loaded drugs, and the precipitated free drugs aggregate and precipitate in water due to their strong hydrophobicity.

[0134] The experimental results are shown in FIG4 , which shows that 10 mM GSH completely depolymerizes the nanodrug and releases the free drug only after incubation with the nanodrug for 4 h.

[0135] III) Preparation of nanoparticles containing different concentrations of GSH

[0136] Prepare nanoparticles containing 0.1, 0.2, 0.5, 1, 2, 4, 5, 8, and 10 mM GSH in a total volume of 200 μL. For the 10 mM concentration, pipette 20 μL of solution (I) into a 1.5 mL centrifuge tube and add 180 μL of the nanoparticles from Example 3.2, mixing thoroughly. Repeat for other concentrations. Incubate on a shaker at 37°C for 4 hours, then photograph the appearance.

[0137] The experimental results are shown in Figure 5. It can be seen that GSH with a concentration lower than 4 mM has almost no effect on the integrity of the nanodrug even after being co-incubated with the nanodrug for 4 hours.

[0138] Example 5: Multiple lipoic acid drugs assembled into nanoparticles with transdermal ability

[0139] 5.1 Nanoparticles Assembled from Lipoic Acid, Dabrafenib, and Chlorin as a Specific Embodiment for Transdermal Studies

[0140] Ⅰ) Nanoparticle preparation is the same as above

[0141] II) Quantification of chlorins in nanoparticles

[0142] Weigh the standard chlorin to prepare a concentration of 6.25 μg mL -1 ,12.5μg mL -1 ,50μg mL -1 ,100μg mL -1 ,200μg mL -1 The DMSO solution was used as the standard solution, and the absorption value at 660 nm was measured by UV-visible absorption spectrometer. The concentration of dihydrochlorin was taken as X value, and the measured absorption value was taken as Y value. The standard curve of dihydrochlorin was obtained as Y=0.005X-0.0058, R 2 =0.9995.

[0143] 5 μL of the purified nanoparticles were taken and disaggregated with 195 μL of DMSO. The absorbance at 660 nm was measured using a UV-visible absorption spectrometer. After being incorporated into the standard curve, the concentration of dihydrochlorin in the nanoparticles was calculated.

[0144] III) Penetration effect in pigskin

[0145] Fresh pig skin was obtained from a local market. Subcutaneous fat was carefully removed and the skin was cut into 1 cm squares. A circle with a radius of 0.5 mm was drawn. An aqueous solution containing 50 μg of chlorin nanoparticles was dripped repeatedly into the marked circle on the skin. After incubation for 10, 60, and 240 minutes, the skin was scrubbed three times with PBS, frozen, cut into 10 μm slices, and placed on a glass slide. Cell nuclei were labeled with DAPI staining solution, and the penetration depth of the drug into the skin was observed by laser confocal microscopy. A chlorin aqueous solution and nanoparticles assembled with chlorin and a chemotherapeutic drug served as controls. Other groups included a chlorin aqueous solution (free Ce6), a nanoparticle group assembled with chlorin and a chemotherapeutic drug (Inf-TDDS), and a nanoparticle group assembled with lipoic acid, the chemotherapeutic drug dabrafenib, and a chlorin nanoparticle group (Sup-TDDS).

[0146] The results are shown in Figure 6. As can be seen from Figure 6, Sup-TDDS can effectively penetrate the stratum corneum. With increasing incubation time, the drug penetrates more and more deeply into the skin. Just 4 hours after administration, it has penetrated over 600 microns into the skin, while free Ce6 and Inf-TDDS barely penetrate the stratum corneum. This demonstrates that the transdermal drug delivery system of the present invention has excellent transdermal penetration.

[0147] 5.2 Nanoparticles Assembled from Lipoic Acid, Trametinib, and Chlorin as a Specific Embodiment for Transdermal Studies

[0148] The operation steps are the same as 5.1, and the experimental results are shown in Figure 7. The experimental results are consistent with Figure 6.

[0149] 5.3 Nanoparticles Assembled from Lipoic Acid, Trametinib, and Hematoporphyrin Monomethyl Ether as a Specific Embodiment for Transdermal Studies

[0150] The procedure was the same as in Example 5.1. The experimental results are shown in Figure 8 . The left figure shows fluorescence imaging of hematoporphyrin monomethyl ether (red) in nanoparticles assembled from trametinib and hematoporphyrin monomethyl ether in pig skin and a merged image of cell nuclei (blue) in pig skin. The right figure shows the single-channel image of hematoporphyrin monomethyl ether (red) in the merged channel of the left figure. The experimental results are consistent with Figure 6 .

[0151] 5.4 Nanoparticles Assembled from Lipoic Acid and Chlorin as a Specific Embodiment for Transdermal Studies

[0152] The procedure was the same as in Example 5.1. The experimental results are shown in Figure 9 . The left figure shows the fluorescence imaging of chlorin (red) in nanoparticles assembled from lipoic acid and chlorin in pig skin and a merged image of cell nuclei (blue) in pig skin. The right figure shows the single-channel image of chlorin (red) in the merged channel of the left figure. The experimental results are consistent with those in Figure 6 .

[0153] These results demonstrate that the transdermal penetration of assemblies containing lipoic acid is significantly greater than that of the free drug and nanoparticles composed of the free drug and a photodynamic agent, demonstrating that lipoic acid can significantly enhance the transdermal penetration of nanoparticles. By adjusting the molar ratio of lipoic acid to the small molecule drug, the penetration depth of the nanoparticles increased from over 600 microns to over 1200 microns. This suggests that adjusting the lipoic acid assembly ratio can regulate the penetration depth of nanoparticles. Therefore, the lipoic acid ratio can be tailored to the specific site of disease onset in the skin, enabling precise disease treatment.

[0154] Example 6: Multiple lipoic acid drugs assembled into nanoparticles have the ability to penetrate the skin in vivo

[0155] In this example, the lipoic acid, trametinib and dihydrochlorin are assembled into nanoparticles as a specific example to verify their transdermal effect on living rats.

[0156] Ⅰ) Stable period of rats

[0157] Female SD rats weighing 200 g were purchased and housed in an animal room for one week.

[0158] II) Transdermal operation in living rats

[0159] The rats were anesthetized, the hair on their backs carefully removed, and a circle with a radius of 0.5 mm was drawn on the back. A solution of nanoparticles containing 50 μg of chlorin e6 was added dropwise to the circle on the back in small amounts. After incubation for 1 hour, 4 hours, and 12 hours, the administration site was scrubbed three times with PBS (phosphate buffered saline). After euthanasia, the skin at the administration site was peeled off, frozen and cut into 10-micron slices and placed on a glass slide. DAPI staining solution was used to mark the cell nuclei, and the penetration depth of the drug in the skin was observed using laser confocal microscopy. Among them, the chlorin aqueous solution and the nanoparticles assembled with chlorin and the chemotherapy drug trametinib were used as controls.

[0160] The results are shown in Figure 10. Figure 10 shows a chlorin aqueous solution (free Ce6), nanoparticles assembled from chlorin and trametinib (Inf-TDDS), and nanoparticles assembled from lipoic acid, trametinib, and chlorin (Sup-TDDS). As shown, Sup-TDDS can effectively penetrate the stratum corneum. With increasing incubation time, the drug penetrates more and deeper into the skin. Twelve hours after administration, it can penetrate over 600 microns into the skin, while free Ce6 and Inf-TDDS barely penetrate the stratum corneum. This demonstrates that the transdermal drug delivery system of the present invention can be applied in vivo.

[0161] Example 7 Mechanism of Transdermal Transdermal Nanoparticles Assembled from Lipoic Acid and Multiple Drugs

[0162] Nanoparticles assembled with lipoic acid, trametinib and dihydrochlorin are used as a specific embodiment for the study of transdermal treatment of skin melanoma.

[0163] Implementation steps:

[0164] Ⅰ) Nanoparticle preparation and quantification are the same as above

[0165] II) Quantification of chlorin in nanoparticles (same as above)

[0166] III) Penetration mechanism in pigskin

[0167] The pigskin treatment and administration method were the same as in Example 6, except that, before the administration and incubation, DTNB (5,5'-dithiobis(2-nitrobenzoic acid) as a thiol exchange inhibitor) was first fully applied to the pigskin surface and incubated with the pigskin for 30 minutes.

[0168] The experimental results are shown in Figure 11, which shows a chlorin aqueous solution (free Ce6), nanoparticles assembled from chlorin and trametinib (Inf-TDDS), and nanoparticles assembled from lipoic acid, trametinib, and chlorin (Sup-TDDS). As shown, after DTNB pretreatment of the skin, Sup-TDDS was unable to effectively penetrate the stratum corneum, while the penetration of free Ce6 and Inf-TDDS was unaffected by DTNB. This indicates that DTNB can completely inhibit the transdermal penetration of nanodrugs, indicating that the transdermal system of the present invention primarily operates via a thiol exchange pathway.

[0169] The ability of lipoic acid, chemotherapy drugs and photodynamic agents assembled into nanoparticles described in Example 8 to treat skin melanoma through transdermal administration

[0170] Nanoparticles assembled with lipoic acid, trametinib and dihydrochlorin are used as a specific embodiment for the study of transdermal treatment of cutaneous melanoma.

[0171] Implementation steps:

[0172] Ⅰ) Nanoparticle preparation and quantification are the same as above

[0173] II) Construction and grouping of skin melanoma mouse models

[0174] Purchase 30 C57BL / 6 female mice weighing 20 g, aged 4-6 weeks. 1x 10 6 B16F10 cells were inoculated into the right thigh of the mouse, and tumors with a size of 50-70 mm were obtained ten days later. 3 A mouse model of skin melanoma was established. Mice were randomly divided into six groups, with five mice in each group: PBS, laser irradiation only (Laser), chlorin aqueous solution with laser irradiation (Free Ce6(+)), nanoparticles assembled with chlorin and trametinib with laser irradiation (Ihf-TDDS(+)), nanoparticles assembled with lipoic acid, chlorin, and trametinib without laser irradiation (Sup-TDDS(-)), and nanoparticles assembled with lipoic acid, chlorin, and trametinib with laser irradiation (Sup-TDDS(+)).

[0175] III) Transdermal drug delivery for melanoma

[0176] Nanoparticles containing 50 μg of chlorin e6 were added to the tumor site of mice in small amounts and multiple times. 12 hours after administration, the tumor site was irradiated with a 660nm laser at a laser intensity of 0.5W for 10 minutes. The drug was administered three times in total, with one administration and laser irradiation every other day. The PBS group and the group composed of nanoparticles assembled with lipoic acid, chlorin e6, and trametinib without laser irradiation were not irradiated. From the first administration, the tumor volume of the mice was observed and recorded (V = a × b 2 / 2; a: tumor length; b: tumor width), body weight, and survival time. Among them, the tumor volume of mice was greater than 2000mm 3 The mice were considered dead. The other groups were operated on in parallel. The experimental results are shown in Figure 12. Figure 12 (a) is a schematic diagram of the treatment method, (b) is a line graph of tumor growth in mice in different dosing groups, (c) is a line graph of tumor growth for each mouse in different dosing groups, (d) is a statistical graph of survival time for mice in different dosing groups, and (e) is a photograph of a mouse in the Sup-TDDS laser irradiation group with complete tumor recovery.

[0177] As shown in Figure 12, Sup-TDDS(+) completely eliminated tumors and significantly prolonged mouse survival compared to PBS, laser, free Ce6(+), Inf-TDDS(+), and Sup-TDDS(-). These results demonstrate that the superior transdermal penetration of the transdermal system of the present invention significantly enhances therapeutic efficacy, achieving complete tumor eradication due to its deep penetration.

[0178] IV) Verification of the effect of trametinib in Sup-TDDS

[0179] After the treatment cycle, mouse tumor tissues were collected for immunohistochemical analysis. The mouse tissues were fixed with 4% paraformaldehyde, dehydrated with 30% sucrose, embedded in embedding medium, and cut into 10 μm tissue sections using a freezing microtome for immunohistochemical analysis.

[0180] As shown in Figure 13, compared with the PBS, laser, free Ce6(+), and Inf-TDDS(+) groups without lipoic acid components, the Sup-TDDS(-) and Sup-TDDS(+) groups showed a significant downregulation of phosphorylated extracellular regulated protein kinase (p-ERK) at the tumor site due to the effect of lipoic acid-assisted drug transdermal delivery. This is the pathway protein inhibited by the trametinib inhibitor, indicating that trametinib can be successfully delivered to tissues and exert an inhibitory effect.

[0181] V) Verification of the immune effect induced by photodynamic therapy of chlorin e6 in Sup-TDDS

[0182] Tumor tissue and tumor-draining lymph nodes were obtained from mice at the end of the treatment cycle for immunohistochemical staining and immune cell analysis. Tumor tissue was fixed with 4% paraformaldehyde, dehydrated with 30% sucrose, embedded in an embedding medium, and cut into 10 μm sections using a freezing microtome for immunohistochemical staining. A portion of the tumor tissue was mechanically ground and sieved to produce a single-cell suspension, after which cells were counted. One million cells from each group were immunostained and analyzed. Tumor-draining lymph nodes were immunostained in the same manner.

[0183] As shown in Figure 14(a), compared to PBS, laser, free Ce6(+), Inf-TDDS(+), and Sup-TDDS(-), the expression of E-cadherin (CRT) in tumor tissues of the Sup-TDDS(+) group was significantly upregulated. This is a marker of immunogenic cell death, and its upregulation indicates enhanced tumor immunity. The significant upregulation of CRT in the Sup-TDDS(+) group suggests that the chlorin e6 delivered to the tumor tissue induced tumor cell apoptosis under laser irradiation, potentially inducing an immune response. Figure 14(b) shows an immunoanalysis of tumor-draining lymph nodes, showing significantly increased expression of dendritic cell maturation markers CD80 and CD86 in the Sup-TDDS(+) group, indicating an immune response. Figure 14(c) further analyzes immune cells in the tumor tissue, revealing significantly increased expression of cytotoxic T cell markers CD4 and CD8 in the Sup-TDDS(+) group, indicating that photodynamic therapy successfully induced an immune response.

[0184] VI) Research on the transdermal treatment of skin melanoma using nanoparticles assembled from lipoic acid, dabrafenib, and dihydrochlorin as a specific embodiment. The implementation steps are the same as those in steps I), II), and III) of the treatment of melanoma using nanoparticles assembled from lipoic acid, trametinib, and dihydrochlorin.

[0185] The results are shown in Figure 15. As can be seen from Figure 15, compared with PBS, laser, free Ce6(+), Inf-TDDS(+), and Sup-TDDS(-), Sup-TDDS(+) can achieve complete elimination of tumors, indicating that the transdermal delivery system of the present invention can be assembled with different drugs and produce therapeutic effects.

[0186] Example 9 Verification of whether skin is damaged after transdermal drug administration

[0187] The specific method was the same as in Example 8. Ten days after the first dose, the cured mice in the Sup-TDDS(+) group were sacrificed. The skin at the laser-irradiated site was excised, cut into 10 μm slices, and stained with H&E. The tissue was observed and photographed under an inverted optical microscope. The skin of healthy, tumor-free mice served as a control. The results are shown in Figure 16.

[0188] As shown in FIG16 , compared with healthy mice without tumor implants, the mouse skin after laser irradiation showed no obvious morphological changes, indicating that the transdermal drug delivery system of the present invention does not cause skin damage and is non-invasive, indicating that the laser intensity used in the present invention does not cause skin trauma.

[0189] Example 10 Comparison of the effects of transdermal administration and traditional intravenous administration in the treatment of skin melanoma

[0190] The nanoparticles assembled from lipoic acid, trametinib and chlorin are used as a specific example in this embodiment.

[0191] Specific implementation steps:

[0192] Ⅰ) Preparation and quantification of nanoparticles and establishment of skin melanoma mouse model were the same as above

[0193] II) Comparison of the efficacy of transdermal and tail vein injections in the treatment of cutaneous melanoma

[0194] Nanoparticles containing 50 μg of chlorin e6 were added to the tumor site of mice in small amounts and multiple times. The same amount of drug was injected into the tail vein. 12 hours after administration, a 660 nm laser with a laser intensity of 0.5 W was used to irradiate the tumor site for 10 minutes. The drug was administered three times, with one dose and laser irradiation every other day. Starting from the first dose, the tumor volume of the mice was observed and recorded (V = a × b 2 / 2; a: tumor length; b: tumor width), body weight. Among them, the tumor volume of mice was greater than 2000mm 3 The mice were considered dead. The results are shown in Figure 17. In Figure 17, Figure a is a schematic diagram of the tail vein injection and transdermal administration methods, Figure b is a line graph of mouse tumor growth under the two different administration methods, Figure c is a line graph of the weight change of mice during treatment, and Figure d is a line graph of the tumor growth of each mouse under the two different administration methods.

[0195] As shown in Figure 17, tail vein injection only inhibited tumor growth in the early stage of administration, but in the later stage of treatment, the tumor grew rapidly again, indicating that tail vein injection cannot effectively eradicate the tumor. In contrast, in the transdermal administration group, the mouse tumor was completely eradicated and there was no recurrence after drug withdrawal, indicating that the transdermal drug delivery system of the present invention greatly improved the cure rate of skin melanoma. The above results show that because transdermal administration can achieve a large amount of drug enrichment in the tumor, complete eradication of the tumor is achieved and the tumor does not recur. However, the systemic administration method of tail vein injection leads to incomplete tumor treatment due to insufficient drug accumulation in the tumor, and the tumor is prone to recurrence.

[0196] Example 11 Comparison of the safety of transdermal administration and traditional intravenous injection after the dosage was increased five times compared to the above dosage

[0197] Specific implementation steps:

[0198] Ⅰ) Preparation and quantification of nanoparticles and establishment of skin melanoma mouse model were the same as above.

[0199] II) Compare the safety of transdermal administration and tail vein injection.

[0200] Nanoparticles containing 250 μg of chlorin were dripped repeatedly into the tumor sites of mice. The same dose was administered via tail vein injection. The mice's behavior was observed. On the fourth day of administration, the mice were sacrificed and blood was collected for liver function assessment. Liver tissue was dissected, sectioned, and stained with hematoxylin and eosin to assess morphology. The results are shown in Figures 16 and 17.

[0201] Figure 18 (a) shows the serum alanine aminotransferase (ALT) levels in mice after a five-fold increase in the dosage, and (b) shows the serum aspartate aminotransferase (AST) levels in mice after the two different dosing methods. As shown in Figure 18 , in the tail vein injection group, ALT and AST levels were significantly elevated, even exceeding the upper limit of normal values, indicating that high-dose tail vein injection can cause systemic toxicity and is not conducive to the treatment of large tumors requiring higher doses. In the transdermal administration group, ALT and AST levels remained at normal levels, demonstrating the high biosafety of the transdermal drug delivery system of the present invention.

[0202] As shown in Figure 19, the tail vein injection group showed multiple inflammatory cell infiltrations in the liver tissue (indicated by black arrows), indicating that tail vein injection damaged the mouse liver. In contrast, the transdermal administration group showed no morphological changes in the liver and no inflammatory cell infiltration, demonstrating the high safety of the transdermal administration of the present invention.

[0203] The above results show that transdermal administration does not cause systemic toxicity because less of the drug enters the systemic circulation. Therefore, large-dose transdermal administration can be used to treat large tumors that require higher doses of drugs.

[0204] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. Application of lipoic acid as a transdermal nanodrug carrier.

2. A nano drug transdermal delivery system, characterized in that: Lipoic acid is used as a drug carrier to encapsulate chemotherapy drugs and / or photodynamic agents, and nanoparticles containing 1,2-dithiolane are formed through self-assembly.

3. The nano drug transdermal delivery system according to claim 1, characterized in that: The molar ratio of lipoic acid to chemotherapeutic drugs or photodynamic agents is 5:1-50:1; The molar ratio of lipoic acid to the chemotherapy drug and the photodynamic agent is 5:1:1-50:1:

1.

4. The nano drug transdermal delivery system according to claim 1, characterized in that: The chemotherapy drug is selected from one or more of trametinib, dabrafenib, paclitaxel, doxorubicin, docetaxel, methotrexate, vemurafenib, and gemcitabine; The photodynamic agent is selected from one or more of dihydrochlorin and hematoporphyrin monomethyl ether.

5. The nano drug transdermal delivery system according to claim 1, characterized in that: The particle size of the nanoparticles is 10-1000 nm.

6. The method for preparing the nano drug transdermal delivery system according to any one of claims 2 to 5, comprising the following steps: The lipoic acid solution and the solution containing the chemotherapeutic drug and / or the photodynamic agent are mixed in water and self-assembled to obtain nanoparticles containing disulfide bonds.

7. The preparation method according to claim 6, characterized in that: The solvent of the lipoic acid solution is DMSO; In the solution containing the chemotherapeutic drug and / or photodynamic agent, the solvent is DMSO.

8. The preparation method according to claim 6, characterized in that: The concentration of the lipoic acid solution is 74 μg / mL-740 μg / mL; In the solution containing the chemotherapeutic drug and / or the photodynamic agent, the total concentration of the chemotherapeutic drug and / or the photodynamic agent is 5.86 μg / mL-293 μg / mL.

9. A transdermal nano drug composition, comprising the nano drug transdermal delivery system according to any one of claims 2 to 5 and a pharmaceutically acceptable adjuvant.

10. Use of the nano drug transdermal delivery system according to any one of claims 2 to 5 or the transdermal nano drug composition according to claim 9 in the preparation of drugs for preventing, alleviating or treating skin diseases.

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