A minoxidil eutectic solvent-based pickering emulsion gel and a preparation method thereof

Abstract

This invention discloses a minoxidil eutectic solvent-based Pickering emulsion gel and its preparation method, comprising: preparing a hydrophobic minoxidil eutectic solvent; preparing a minoxidil eutectic solvent-based Pickering emulsion; and preparing a minoxidil eutectic solvent-based Pickering emulsion gel. In the hydrophobic minoxidil eutectic solvent, the hydrogen bond donor includes acetic acid, octanoic acid, decanoic acid, or lauric acid, and the hydrogen bond acceptor is... L - Menthol or thymol. The minoxidil eutectic solvent-based Pickering emulsion is stabilized by nanoparticles such as cellulose nanocrystals, zein nanoparticles, nano-silica, or nano-calcium carbonate. A minoxidil eutectic solvent-based Pickering emulsion gel is prepared by adding a gel matrix, including carbomer 940, carbomer 934, sodium carboxymethyl cellulose, chitosan, potassium alginate, poloxamer 188, or poloxamer 407. The minoxidil eutectic solvent-based Pickering emulsion gel prepared by this invention has the advantage of high drug loading.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical formulation technology, specifically relating to a minoxidil eutectic solvent-based pickering emulsion gel and its preparation method. Background Technology

[0002] Androgenetic alopecia is a common type of hair loss. While it doesn't cause obvious physical discomfort, it can negatively impact a patient's mental state and worsen their quality of life. Topical minoxidil is a first-line treatment for androgenetic alopecia. Minoxidil is an antihypertensive drug listed in the Chinese Pharmacopoeia, which dilates blood vessels to treat various types of hypertension. Clinical applications have shown that minoxidil can cause adverse reactions such as hair growth and even hirsutism. Therefore, minoxidil preparations have been developed for the treatment of hair loss and alopecia areata. Currently, it is believed that the mechanism by which minoxidil promotes hair growth mainly involves stimulating the proliferation and differentiation of hair follicle cells, promoting the transformation of hair follicles from the resting phase to the anagen phase, and improving local blood circulation.

[0003] Because minoxidil is only slightly soluble in water, most commercially available minoxidil formulations use organic solvents such as ethanol and 1,2-propanediol to improve its solubility. On the one hand, these organic solvents are volatile, and after application, minoxidil easily crystallizes on the skin surface, affecting drug delivery and absorption. More seriously, 1,2-propanediol is a sensitizing substance that can cause skin redness, dryness, itching, and peeling, severely reducing patient compliance and affecting treatment efficacy. Organic solvents such as ethanol can damage the skin's stratum corneum, enhancing the drug's ability to penetrate the epidermis, further amplifying the disadvantage of minoxidil's high permeability, leading to side effects such as decreased blood pressure and hirsutism in other areas. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of topical minoxidil formulations by providing a minoxidil eutectic solvent-based pickerling emulsion gel and its preparation method.

[0005] The minoxidil eutectic solvent-based pickerling emulsion gel of the present invention has the following characteristics.

[0006] A method for preparing a minoxidil eutectic solvent-based Pickering emulsion gel includes the following steps:

[0007] (1) Minoxidil was mixed with hydrogen bond acceptor and hydrogen bond donor and heated to obtain a hydrophobic minoxidil eutectic solvent;

[0008] (2) After mixing hydrophobic minoxidil eutectic solvent with water, nanoparticles were added as emulsifiers and ultrasonic homogenization was performed to prepare minoxidil eutectic solvent-based Pickering emulsion.

[0009] (3) Add a gel matrix to the minoxidil eutectic solvent-based Pickering emulsion and stir to form a minoxidil eutectic solvent-based Pickering emulsion gel.

[0010] To further achieve the objectives of this invention, preferably, in step (1), the hydrogen bond donor includes one or more of acetic acid, octanoic acid, decanoic acid, or lauric acid; the hydrogen bond acceptor is... L - Menthol or thymol; the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:4-4:1; the mass fraction of minoxidil in the hydrophobic minoxidil eutectic solvent is 4.6-30.0 wt%; the heating reaction time is 0.2-1.0 h, and the temperature is 40-80 ℃.

[0011] Preferably, in step (2), the mass ratio of the hydrophobic minoxidil eutectic solvent to water is 1:4-1:20; the nanoparticles include one or more of cellulose nanocrystals, zein nanoparticles, nano-silica, or nano-calcium carbonate; the cellulose nanocrystals are rod-shaped nanoparticles with a major diameter of 100-400 nm and a minor diameter of 20-50 nm; the zein nanoparticles are spherical nanoparticles with a diameter of 200 nm; the nano-silica is spherical nanoparticles with a diameter of 7 nm; the nano-calcium carbonate is spherical nanoparticles with a diameter of 40 nm; in the minoxidil eutectic solvent-based Pickering emulsion, the mass fraction of nanoparticles is 0.5-3.0 wt%, and the mass fraction of minoxidil is 0.2-5.0 wt%; the ultrasonic homogenization power is 100-500 W, the frequency is 20 kHz, and the homogenization time is 1-10 min.

[0012] Preferably, in step (3), the gel matrix includes one or more of carbomer 940, carbomer 934, sodium carboxymethyl cellulose (viscosity 1000-1500 mPa·s), chitosan (average molecular weight 150 kDa), poloxamer 188, or poloxamer 407; and the mass fraction of the gel matrix in the minoxidil eutectic solvent-based Pickering emulsion gel is 0.5-1.5 wt%.

[0013] Compared with existing technologies, the minoxidil eutectic solvent-based pickerine emulsion gel prepared by this invention has the advantages of high drug loading, simple preparation method and good hair follicle targeting.

[0014] The instruments used in this invention to detect the structure and properties of minoxidil eutectic solvent-based Pickering emulsion gel are as follows.

[0015] 1. The instrument used for nuclear magnetic resonance spectroscopy analysis was a Bruker Avance III HD 400 MHz nuclear magnetic resonance spectrometer.

[0016] 2. The instrument used for infrared spectroscopy analysis was a Nicolet 5700 infrared spectrometer.

[0017] 3. The instrument used for differential scanning calorimetry analysis was a Q2000 differential scanning calorimeter.

[0018] 4. The scanning electron microscopy analysis was performed using a FEI Quanta 250 scanning electron microscope.

[0019] 5. The particle size analysis and zeta potential measurement were performed using a Malvern Zetasizer Nano ZS90 nanoparticle size potentiometer.

[0020] 6. The instrument used for transmission electron microscopy analysis was a Tecnai G2 Spirit BioTWIN transmission electron microscope.

[0021] 7. The instrument used for the hair follicle targeting study was a Zeiss LSM 900 laser confocal microscope.

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 The results are from the nuclear magnetic resonance spectroscopy analysis of the minoxidil eutectic solvent prepared in Example 1.

[0024] Figure 2 The results are infrared spectral analysis of the minoxidil eutectic solvent prepared in Example 1.

[0025] Figure 3 The results are differential scanning calorimetry analysis results of the minoxidil eutectic solvent prepared in Example 1.

[0026] Figure 4 The results are obtained by scanning electron microscopy analysis of the minoxidil eutectic solvent prepared in Example 1.

[0027] Figure 5 These are the results of transmission electron microscopy analysis of minoxidil eutectic solvent-based Pickering emulsion.

[0028] Figure 6 These are the results of scanning electron microscopy analysis of minoxidil eutectic solvent-based Pickering emulsion gel. Detailed Implementation

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0030] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0031] Example 1

[0032] (1) Weigh 1.56 g (10.0 mmol) of... L Menthol, 2.88 g (20.0 mmol) of caprylic acid and 1.48 g (7.1 mmol) of minoxidil were placed in a 10 mL round-bottom flask, fitted with a reflux apparatus, heated in a 60 °C water bath, and stirred for 0.5 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 25.0 wt%.

[0033] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 8.0 g of water, add 0.05 g of cellulose nanocrystals (200 nm long axis, 30 nm short axis), and homogenize with ultrasonic power of 200 W and frequency of 20 kHz for 2 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 5.0 wt%.

[0034] (3) Under stirring reaction conditions, 0.5 wt% of sodium carboxymethyl cellulose (viscosity 1000-1500 mPa·s) was added to the minoxidil eutectic solvent-based Pickering emulsion to form a minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 5.0 wt%.

[0035] Example 2

[0036] (1) Weigh 1.50 g (10.0 mmol) of thymol, 5.77 g (40.0 mmol) of octanoic acid and 3.12 g (14.9 mmol) of minoxidil into a 50 mL round bottom flask, assemble a reflux apparatus, heat in an 80 °C water bath, stir and react for 1.0 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 30.0 wt%.

[0037] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 20.0 g of water, add 0.44 g of zein nanoparticles (diameter 200 nm), and homogenize with ultrasonic power of 300 W and frequency of 20 kHz for 10 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 2.7 wt%.

[0038] (3) Under stirring reaction conditions, 1.5 wt% of carbomer 934 was added to minoxidil eutectic solvent-based Pickering emulsion to form minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 2.6 wt%.

[0039] Example 3

[0040] (1) Weigh out 6.25 g (40.0 mmol) of L Menthol, 0.60 g (10.0 mmol) of acetic acid and 0.33 g (1.6 mmol) of minoxidil were placed in a 10 mL round-bottom flask, fitted with a reflux apparatus, heated in a water bath at 40 °C, and stirred for 0.2 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 4.6 wt%.

[0041] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 20.0 g of water, add 0.22 g of nano-calcium carbonate particles (40 nm in diameter), and homogenize with ultrasonic power of 100 W and frequency of 20 kHz for 7 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 0.4 wt%.

[0042] (3) Under stirring reaction conditions, 1.5 wt% of sodium carboxymethyl cellulose (viscosity 1000-1500 mPa·s) was added to the minoxidil eutectic solvent-based Pickering emulsion to form a minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 0.4 wt%.

[0043] Example 4

[0044] (1) Weigh 3.12 g (20.0 mmol) of... L Menthol, 1.72 g (10.0 mmol) of decanoic acid and 0.25 g (1.2 mmol) of minoxidil were placed in a 10 mL round-bottom flask, fitted with a reflux apparatus, heated in a water bath at 70 °C, and stirred for 0.6 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 5.0 wt%.

[0045] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 10.0 g of water, add 0.06 g of nano-calcium carbonate particles (200 nm in diameter), and homogenize with ultrasonic power of 500 W and frequency of 20 kHz for 3 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 0.8 wt%.

[0046] (3) Under stirring reaction conditions, 1.0 wt% of chitosan (average molecular weight 150 kDa) was added to minoxidil eutectic solvent-based Pickering emulsion to form minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 0.8 wt%.

[0047] Example 5

[0048] (1) Weigh 1.56 g (10.0 mmol) of... L Menthol, 6.00 g (30.0 mmol) of lauric acid and 0.65 g (3.1 mmol) of minoxidil were placed in a 50 mL round-bottom flask, fitted with a reflux apparatus, heated in a 60 °C water bath, and stirred for 1.0 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 7.9 wt%.

[0049] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 30.0 g of water, add 0.32 g of cellulose nanocrystals (400 nm long axis and 50 nm short axis), and homogenize with ultrasonic power of 300 W and frequency of 20 kHz for 5 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 0.5 wt%.

[0050] (3) Under stirring reaction conditions, 1.0 wt% of poloxamer 188 was added to minoxidil eutectic solvent-based Pickering emulsion to form minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 0.5 wt%.

[0051] Example 6

[0052] (1) Weigh 1.50 g (10.0 mmol) of thymol, 1.72 g (10.0 mmol) of n-decanoic acid and 1.08 g (5.16 mmol) of minoxidil into a 10 mL round bottom flask, assemble a reflux apparatus, heat in a water bath at 60 °C, and stir for 0.2 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 25.1 wt%.

[0053] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 10.0 g of water, add 0.36 g of cellulose nanocrystals (100 nm long axis and 20 nm short axis), and homogenize with ultrasonic power of 300 W and frequency of 20 kHz for 3 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 4.1 wt%.

[0054] (3) Under stirring reaction conditions, 1.0 wt% of carbomer 940 was added to minoxidil eutectic solvent-based Pickering emulsion to form minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 4.0 wt%.

[0055] Example 7

[0056] (1) Weigh 1.50 g (10.0 mmol) of thymol, 2.88 g (20.0 mmol) of octanoic acid and 1.46 g (7.0 mmol) of minoxidil into a 10 mL round-bottom flask, assemble a reflux apparatus, heat in a water bath at 60 °C, and stir for 0.2 h to obtain a pale yellow clear solution, which is a hydrophobic eutectic solvent for minoxidil, wherein the mass fraction of minoxidil is 25.0 wt%.

[0057] (2) Weigh 2.0 g of hydrophobic minoxidil eutectic solvent, mix with 40.0 g of water, add 0.21 g of nano silica particles (7 nm in diameter), and homogenize with ultrasonic power of 400 W and frequency of 20 kHz for 1 min to obtain minoxidil eutectic solvent-based Pickering emulsion, wherein the mass fraction of minoxidil is 1.2 wt%.

[0058] (3) Under stirring reaction conditions, 1.5 wt% of poloxamer 407 was added to minoxidil eutectic solvent-based Pickering emulsion to form minoxidil eutectic solvent-based Pickering emulsion gel, wherein the mass fraction of minoxidil was 1.2 wt%.

[0059] Example 1

[0060] Characterized by proton nuclear magnetic resonance spectroscopy L - Menthol / octanoic acid / minoxidil eutectic solvent. Take the solution prepared in Example 1. L - The 1H NMR spectrum was determined using a eutectic solvent of menthol / octanoic acid / minoxidil, and the results are as follows: Figure 1 As shown LThe eutectic solvent of menthol / octanoic acid / minoxidil showed hydrogen signals at chemical shifts of 5.90, 5.25, 3.45, 2.30, 2.16, 1.95, 1.63, 1.27, 1.11, and 1.02-0.79 ppm in a proton NMR spectrum (400 MHz, CDCl3), which is consistent with the starting material. L - The NMR signals of menthol, caprylic acid and minoxidil are consistent. L - In the eutectic solvent of minoxidil (menthol / octanoic acid / minoxidil), the chemical shift of the amino group H of minoxidil moves to a higher field, suggesting that minoxidil forms an eutectic solvent via the amino group.

[0061] Example 2

[0062] Characterization using infrared spectroscopy L - Menthol / octanoic acid / minoxidil eutectic solvent. Take the solution prepared in Example 1. L Infrared spectroscopy was performed using a eutectic solvent of menthol / octanoic acid / minoxidil, and the results are as follows: Figure 2 As shown. L - Menthol / octanoic acid / minoxidil eutectic solvent at wavenumbers of 3461, 3321, 3187, 2953, 2925, 2856, 1710, 1654, 1616, 1562, 1522, 1477, 1462, 1447, 1403, 1377, 1250, 1227, 1177, 1104, 1044, 1023, 993, 976, 918, 876, 846, 760, 724, 547 and 458 cm⁻¹ -1 There are infrared characteristic peaks at this location, which are consistent with the raw materials. L The infrared characteristic peaks of menthol, caprylic acid, and minoxidil are consistent, suggesting the formation of a eutectic solvent.

[0063] Example 3

[0064] Differential scanning calorimetry was used to determine L - Melting point of the eutectic solvent of menthol / octanoic acid / minoxidil. Take the sample prepared in Example 1. L Differential scanning calorimetry was performed using a eutectic solvent of menthol / octanoic acid / minoxidil, and the results are as follows: Figure 3 As shown. L -Melted in a eutectic solvent of menthol / octanoic acid / minoxidil T onset The value was -33.7 ℃, significantly lower than... L - Menthol (melting point 42 °C) and octanoic acid (melting point 17 °C) confirmed the formation of a eutectic solvent.

[0065] Example 4

[0066] The prepared material was examined using a scanning electron microscope.L Structural analysis was performed using a eutectic solvent of menthol / octanoic acid / minoxidil. The solvent prepared in Example 1 was... L A eutectic solvent of menthol / octanoic acid / minoxidil was applied to a silicon wafer, which was then lyophilized and sputter-coated with gold. The morphology of the sample was observed using a scanning electron microscope at an accelerating voltage of 20 kV. The scanning electron microscopy analysis results are as follows: Figure 4 As shown, no crystals were observed in the field of view magnified 50,000 times, indicating that the eutectic solvent of minoxidil exhibits an amorphous structure.

[0067] Example 5

[0068] The particle size distribution of the prepared minoxidil eutectic solvent-based Pickering emulsion was analyzed using dynamic light scattering (DLS) technology. The minoxidil eutectic solvent-based Pickering emulsion prepared in Example 1 was diluted 100-fold with distilled water and sonicated for 3 min to prevent particle agglomeration. The particle size distribution of the sample was measured using a laser particle size analyzer, and the measurement was repeated three times. The results showed that the average particle size of the prepared minoxidil eutectic solvent-based Pickering emulsion was 679.2 ± 103.4 nm, suitable for delivery to the target site via hair follicle delivery.

[0069] Example 6

[0070] The structure of the prepared minoxidil eutectic solvent-based Pickering emulsion was analyzed using transmission electron microscopy. The minoxidil eutectic solvent-based Pickering emulsion prepared in Example 1 was diluted 100-fold with distilled water and then dropped onto a copper grid with a support film. After 2 min, the surface liquid was blotted dry with filter paper. One drop of 2% phosphotungstic acid was added, and after another 2 min, the surface liquid was blotted dry with filter paper. After the sample dried, its morphology was observed using a transmission electron microscope at an accelerating voltage of 120 kV. The results are as follows: Figure 5 As shown in the figure, the prepared minoxidil eutectic solvent-based Pickering emulsion is stabilized by cellulose nanocrystals and exhibits typical Pickering emulsion structural characteristics.

[0071] Example 7

[0072] The structure of the prepared minoxidil eutectic solvent-based Pickering emulsion gel was analyzed using scanning electron microscopy. The minoxidil eutectic solvent-based Pickering emulsion gel prepared in Example 1 was coated onto a silicon wafer, lyophilized, and then sputter-coated with gold. The morphological characteristics of the sample were observed using scanning electron microscopy at an accelerating voltage of 10 kV. The results are as follows: Figure 6 As shown in the figure, the minoxidil eutectic solvent-based Pickering emulsion gel structure is highly ordered and has a three-dimensional network structure.

[0073] Example 8

[0074] A hair regeneration model was established using male Kunming mice to evaluate the follicular delivery effect of the drug formulation. Animal experiments were conducted according to the experimental protocol approved by the ethics committee. Eighteen male Kunming mice were selected, anesthetized with ether, and their backs were shaved and waxed. The mice were randomly divided into three groups: one group was treated with a commercially available minoxidil tincture labeled with coumarin 6 fluorescently, another group was treated with a minoxidil eutectic solvent-based Pickering emulsion prepared in Example 1 labeled with coumarin 6 fluorescently, and the third group was treated with a minoxidil eutectic solvent-based Pickering emulsion gel prepared in Example 1 labeled with coumarin 6 fluorescently. After a certain period of time, the mice were euthanized, and a 1 cm sample was taken from the treatment site. 2 After cleaning the skin with saline solution and mounting the slides, observation was performed using a laser confocal microscope. Minoxidil eutectic solvent-based Pickering emulsion and gel were found to be more readily delivered to the hair follicles, while commercially available minoxidil tinctures were delivered only slowly. These results demonstrate that minoxidil eutectic solvent-based Pickering emulsion and gel penetrate the hair follicle more easily via the follicular delivery pathway, exhibiting better hair loss treatment efficacy compared to commercially available minoxidil tinctures.

Claims

1. A method for preparing a minoxidil eutectic solvent-based Pickering emulsion gel, characterized in that: The process includes the following steps: (1) mixing minoxidil with a hydrogen bond acceptor and a hydrogen bond donor, and heating the mixture to obtain a hydrophobic minoxidil eutectic solvent; the hydrogen bond donor is one or more of acetic acid, octanoic acid, decanoic acid, or lauric acid; the hydrogen bond acceptor is L-menthol or thymol; the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:4-4:1; the mass fraction of minoxidil in the hydrophobic minoxidil eutectic solvent is 4.6-30.0 wt%; the heating reaction time is 0.2-1.0 h, and the temperature is 40-80 °C. ℃; (2) Mix hydrophobic minoxidil eutectic solvent with water, add nanoparticles as emulsifier, and perform ultrasonic homogenization to prepare minoxidil eutectic solvent-based Pickering emulsion; the mass ratio of the hydrophobic minoxidil eutectic solvent to water is 1:4-1:20; the nanoparticles are one or more of cellulose nanocrystals, zein nanoparticles, nano silica or nano calcium carbonate; the cellulose nanocrystals are rod-shaped nanoparticles with a major diameter of 100-400 nm and a minor diameter of 20-50 nm; the zein nanoparticles are spherical nanoparticles with a diameter of 200 nm; the nano silica are spherical nanoparticles with a diameter of 7 nm; the nano calcium carbonate are spherical nanoparticles with a diameter of 40 nm; in the minoxidil eutectic solvent-based Pickering emulsion, the mass fraction of nanoparticles is 0.5-3.0 wt%, and the mass fraction of minoxidil is 0.2-5.0 wt%. wt%; the power of the ultrasonic homogenization is 100-500 W, the frequency is 20 kHz, and the time is 1-10 min; (3) a gel matrix is ​​added to the minoxidil eutectic solvent-based Pickering emulsion, and the mixture is stirred to form a minoxidil eutectic solvent-based Pickering emulsion gel; the gel matrix is ​​one or more of carbomer 940, carbomer 934, sodium carboxymethyl cellulose with a viscosity of 1000-1500 mPa·s, chitosan with an average molecular weight of 150 kDa, poloxamer 188 or poloxamer 407; the mass fraction of the gel matrix in the minoxidil eutectic solvent-based Pickering emulsion gel is 0.5-1.5 wt%.

2. The method for preparing minoxidil eutectic solvent-based Pickering emulsion gel as described in claim 1, characterized in that: In step (1), the hydrogen bond acceptor is L-menthol, the hydrogen bond donor is octanoic acid, and the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:2; the mass fraction of minoxidil in the hydrophobic minoxidil eutectic solvent is 25.0 wt%; the heating reaction temperature is 60 ℃ and the time is 0.5 h.

3. The method for preparing minoxidil eutectic solvent-based Pickering emulsion gel as described in claim 1, characterized in that: In step (2), the mass ratio of the hydrophobic minoxidil eutectic solvent to water is 1:4; the nanoparticles are cellulose nanocrystals, which are rod-shaped nanoparticles with a long diameter of 200 nm and a short diameter of 30 nm; in the minoxidil eutectic solvent-based Pickering emulsion, the mass fraction of nanoparticles is 0.5 wt%, and the mass fraction of minoxidil is 5.0 wt%; the ultrasonic homogenization power is 200 W, the frequency is 20 kHz, and the time is 2 min.

4. The method for preparing minoxidil eutectic solvent-based Pickering emulsion gel as described in claim 1, characterized in that: In step (3), the gel matrix is ​​sodium carboxymethyl cellulose with a viscosity of 1000-1500 mPa·s; in the minoxidil eutectic solvent-based Pickering emulsion gel, the mass fraction of the gel matrix is ​​0.5 wt%.

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