Ionic liquid microemulsion and application thereof in external preparation drug-loading matrix

Abstract

The invention discloses an ionic liquid microemulsion and application thereof in an external preparation drug-loading matrix, and belongs to the field of pharmaceutical preparations, the microemulsion takes choline lactate ionic liquid or choline acetate as a hydrophilic phase and oleic acid as an oleophylic phase, and is supplemented with a mixed emulsifier; the mixed emulsifier is prepared by mixing polyoxyethylene 40 hydrogenated castor oil and diethylene glycol monoethyl ether according to the mass ratio of 3: 1-1: 3, the hydrophilic phase accounts for 10-30% by mass, the oleophylic phase accounts for 3-20% by mass, and the emulsifier accounts for 50-80% by mass, an ionic liquid micro-emulsion is constructed, the raw material medicine and the ionic liquid micro-emulsion are mixed, and the medicine carrying micro-emulsion preparation is obtained; the process is simple, the used ionic liquid is simple and easy to obtain, the requirement for equipment needed in the preparation process is low, and the obtained ionic liquid microemulsion can remarkably improve the solubility of insoluble drugs and promote the transdermal efficiency of the drugs and is suitable for being used as a drug carrying matrix of an external preparation.

Description

Technical Field

[0001] The invention relates to an ionic liquid microemulsion and also to the application of the ionic liquid microemulsion as a drug-carrying matrix in a transdermal external preparation, belonging to the field of pharmaceutical preparations. Background Art

[0002] Ionic liquids are generally defined as organic salts composed of organic cations and organic (inorganic) anions, which are liquid below 100°C. They have unconventional medicinal potential, such as excellent biocompatibility, the ability to promote drug penetration through the skin barrier, negligible vapor pressure, high conductivity, wide liquid range and thermal stability, which can be adjusted by flexibly adjusting the combination of cations and anions.

[0003] Microemulsions are usually single optically isotropic and thermodynamically stable liquid solutions composed of water, oil, emulsifiers and co-emulsifiers. Generally speaking, the particle size of microemulsions is in the range of 1-200nm. Therefore, microemulsions exhibit ultra-low interfacial tension, large interfacial area and transparency. Due to their special physical and chemical properties, microemulsions are used as new drug carriers to improve drug efficacy and reduce toxic side effects.

[0004] There are various routes of drug administration, mainly including oral, injection and transdermal administration. Oral administration has high compliance, but the efficacy may be reduced due to the first-pass effect. Injection administration can act quickly and avoid the first-pass effect, but it may cause pain and discomfort. Transdermal administration delivers drugs into the body through the skin, which can achieve local or systemic therapeutic effects. Compared with most traditional drug delivery methods, transdermal administration has many advantages. As a non-invasive drug delivery method, it has the advantages of high patient compliance, no impact on first-pass elimination in the liver, fewer side effects, and convenient drug preparation and transportation. However, the difficulty faced by transdermal administration is that the stratum corneum of the skin hinders drug penetration. Many drugs are difficult to pass through the skin barrier due to poor permeability. In order to overcome this problem, researchers have been exploring ways to improve the transdermal permeability of drugs.

[0005] Ionic liquid microemulsion is a cross system of ionic liquid and microemulsion, which takes into account the advantages of both systems. The thermal stability of classical microemulsion is low. The increase in temperature will cause the water and organic solvent in the system to volatilize, leading to the destruction of the microemulsion. The microemulsion constructed by selecting appropriate ionic liquids can have high thermal stability. Ionic liquids can increase the solubility of drugs, so microemulsion systems containing ionic liquids can solubilize a variety of water-insoluble drugs; by utilizing the designability of each part of the ionic liquid to adjust the structure and properties of ionic liquid microemulsions, the application range of microemulsions can be significantly expanded. In addition, ionic liquids, as a new type of penetration enhancer, can significantly promote the transdermal absorption of drugs because they can disrupt the lipid arrangement of the skin. Therefore, by using ionic liquid as one of the components of the microemulsion, an ionic liquid microemulsion for transdermal administration is prepared, which can not only improve the solubility of the drug, but also promote the penetration of the drug through the skin, thereby enhancing the transdermal delivery efficiency of the drug. Summary of the invention

[0006] The invention aims to provide an ionic liquid microemulsion, which uses a hydrophilic ionic liquid as a hydrophilic phase, oleic acid as a lipophilic phase, and is supplemented with a mixed emulsifier, wherein the mixed emulsifier is polyoxyethylene 40 hydrogenated castor oil and diethylene glycol ethyl ether miscible in a mass ratio of 3:1-1:3, and in terms of mass percentage, the hydrophilic phase ratio is 10-30%, the lipophilic phase ratio is 3-20%, and the mixed emulsifier is 50%-80%, so as to construct the ionic liquid microemulsion.

[0007] The hydrophilic phase is choline lactate ionic liquid or choline acetate ionic liquid or the two are miscible in any proportion.

[0008] The molar ratio of the lactic acid or acetic acid to choline is 1:2-2:1.

[0009] The ionic liquid microemulsion has a clear and transparent appearance and a particle size of less than 200 nm.

[0010] The method for preparing the ionic liquid microemulsion comprises the following steps: adding a hydrophilic phase, a lipophilic phase and a mixed emulsifier into a reaction container in proportion, and stirring until the mixture is clear and transparent, thereby obtaining the ionic liquid microemulsion.

[0011] Another object of the present invention is to provide an application of the ionic liquid microemulsion as a drug-carrying matrix in an external preparation, wherein the drug substance is mixed with the ionic liquid microemulsion and stirred until the mixture is clear and transparent to obtain a drug-carrying ionic liquid microemulsion preparation.

[0012] The technical solution of the present invention has the following beneficial effects:

[0013] (1) The ionic liquid microemulsion has the advantages of both ionic liquid and microemulsion. Ionic liquid can significantly improve the solubility of poorly soluble drugs and promote drug penetration through the skin barrier by disrupting skin lipids. On the other hand, the microemulsion system can optimize the hydrophilic-lipophilic balance of the preparation by adjusting the emulsifier and the oil phase to further enhance the transdermal effect of the drug.

[0014] (2) It has good biocompatibility and has little effect on the vitality of normal cells while effectively increasing the drug transdermal efficiency.

[0015] (3) The present invention has low requirements on equipment, low raw material prices, and simple preparation steps.

[0016] (4) The ionic liquid can be used as a drug carrier and prepared into drug-loaded microemulsions with a variety of drug molecules, and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Pseudo-ternary phase diagram of the microemulsion of Example 1.

[0018] Figure 2 The maximum solubility of quercetin in each component in Example 5.

[0019] Figure 3 The cumulative drug permeation over time in Example 8.

[0020] Figure 4 Fluorescence imaging of mouse skin sections after 24 h of treatment with Nile Red / phosphate buffer, Nile Red / lactated choline, and Nile Red / ionic liquid microemulsions.

[0021] Figure 5 Cell viability of immortalized human keratinocytes after incubation with different doses of lactate choline ionic liquid microemulsions for 30 min. DETAILED DESCRIPTION

[0022] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0023] Example 1

[0024] The ionic liquid microemulsion described in this embodiment, 10.58g lactic acid (85%) is added to 27.54g choline hydroxide solution (44%), stirred for 24h, to obtain a lactic acid choline ionic liquid solution, and then a rotary evaporator is used to rotary evaporate for 2h at 70°C, and then placed in a vacuum drying oven for drying for 2h to obtain a lactic acid choline ionic liquid. Polyoxyethylene 40 hydrogenated castor oil and diethylene glycol monoethyl ether are stirred in a mass ratio of 1:3, 1:2, 1:1, 2:1 and 3:1 to form a mixed emulsifier, and oleic acid and the mixed emulsifier are mixed in a mass ratio of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2 and 9:1. After mixing evenly, the lactic acid choline ionic liquid is added dropwise, and stirred continuously until the system becomes turbid, and the amount of the lactic acid choline ionic liquid is recorded each time. The mass ratio of oleic acid, polyoxyethylene 40 hydrogenated castor oil, diethylene glycol ethyl ether and lactic acid choline ionic liquid is plotted into a pseudo-ternary phase diagram to find the microemulsion region of three-phase equilibrium. The upper region in the diagram is the microemulsion region, and the microemulsion can be configured in this region (such as Figure 1 ).

[0025] Example 2

[0026] The ionic liquid microemulsion described in this embodiment is prepared by adding 10.58g of lactic acid (85%) to 27.54g of choline hydroxide solution (44%), stirring for 24h to obtain a lactic acid choline ionic liquid solution, and then using a rotary evaporator to rotary evaporate for 2h at 70°C, and then putting it into a vacuum drying oven for drying for 2h to obtain a lactic acid choline ionic liquid. Accurately weigh 2.0g of lactic acid choline ionic liquid, 1.0g of oleic acid, 3.5g of emulsifier polyoxyethylene 40 hydrogenated castor oil, and 3.5g of co-emulsifier diethylene glycol ethyl ether in a reaction container, and stir at a constant temperature of 30°C until clear to obtain an ionic liquid microemulsion.

[0027] Example 3

[0028] The ionic liquid microemulsion described in this embodiment is prepared by adding 6.00 g of acetic acid to 27.54 g of choline hydroxide solution (44%), stirring for 24 h to obtain a choline acetate ionic liquid solution, and then using a rotary evaporator to rotary evaporate for 2 h at 70 ° C, and then placing it in a vacuum drying oven to dry for 2 h to obtain a choline acetate ionic liquid. Accurately weigh 2.0 g of choline acetate ionic liquid, 1.0 g of oleic acid, 3.5 g of emulsifier polyoxyethylene 40 hydrogenated castor oil, and 3.5 g of co-emulsifier diethylene glycol ethyl ether in a reaction container, and stir at a constant temperature of 30 ° C until clear to obtain an ionic liquid microemulsion.

[0029] Example 4

[0030] The drug-loaded ionic liquid microemulsion described in this embodiment is prepared by adding 10.58g of lactic acid (85%) to 27.54g of choline hydroxide solution (44%), stirring for 24h to obtain a lactic acid choline ionic liquid solution, and then using a rotary evaporator to evaporate for 2h at 70°C, and then placing it in a vacuum drying oven to dry for 2h to obtain a lactic acid choline ionic liquid. Accurately weigh 250.00mg of quercetin in a centrifuge tube, add 5.0g of the prepared lactic acid choline ionic liquid, vortex for 2 minutes, and then use water bath ultrasound for 10min to completely dissolve the drug to obtain a drug-loaded lactic acid choline ionic liquid (containing 50mg / g of the drug). Accurately weigh 2.0g of the drug-loaded lactic acid choline ionic liquid, 1.0g of oleic acid, 3.5g of emulsifier polyoxyethylene 40 hydrogenated castor oil, and 3.5g of co-emulsifier diethylene glycol ethyl ether in a reaction container, stir until clear at a constant temperature of 30°C, and use water bath ultrasound to obtain a drug-loaded ionic liquid microemulsion.

[0031] Example 5

[0032] An excess of quercetin was added to 1 mL of ultrapure water and Example 2 (choline lactate ionic liquid microemulsion) respectively, and stirred at 25°C for 24 h. The undissolved drug was filtered using a 0.22 μm microporous filter membrane. The absorbance of quercetin was determined by UV-visible spectrophotometry, and the quercetin solubility was calculated by substituting it into the standard curve to determine the maximum solubility of the drug in different solvents. The results are shown in Figure 2 , ionic liquid microemulsion significantly improved the solubility of quercetin.

[0033] Example 6

[0034] Roflumilast was gradually added to the quantitative ultrapure water and the ionic liquid microemulsion obtained in Example 3 until a white drug precipitate was produced. Compared with ultrapure water, the ionic liquid microemulsion prepared in Example 3 significantly improved the solubility of Roflumilast.

[0035] Example 7

[0036] The Zeta potential and particle size of the drug-loaded ionic liquid microemulsion obtained in Example 4 were measured using a particle size analyzer. A small amount of sample was added to the measuring cell, placed in the measuring hole, and measured three times at room temperature. The average value was taken as the particle size of the drug-loaded ionic liquid microemulsion. The average particle size was 104.93 nm and the Zeta potential was -8.18 mV. The test was repeated on the 1st, 3rd, 5th, and 7th days, and the particle size and potential did not change significantly.

[0037] Example 8

[0038] Balb / c mice of 10 weeks old were selected and killed by spinal dislocation, and the back hair was removed with a depilatory apparatus, and the back skin was then excised, and then the subcutaneous fat was removed and washed with a phosphate buffer solution, and stored at -20°C before use.

[0039] The quercetin-loaded ionic liquid microemulsion was prepared according to the method in Example 4. The prepared mouse skin was cut into 2.5 cm 2 , fixed on the diffusion cell, and take each preparation on the supply chamber side, while the mouse skin dermis faces the receiving chamber (volume 7.5mL, pH=7.4 phosphate buffer solution as the receiving medium), the temperature is (37±0.5)℃, the magnetic stirrer is placed in the receiving chamber, filled with receiving liquid, bubbles are removed, pre-balanced for 1h, 0.5mL is sampled from the receiving pool at different time points, and an equal amount of receiving liquid is added to the receiving pool to remove bubbles. HPLC is used to determine the concentration of quercetin, and the cumulative permeation per unit area (Qn) is calculated. The average value is taken to draw the in vitro transdermal permeation curve. The formula for cumulative permeation per unit area is as follows:

[0040]

[0041] Among them, C n is the drug mass concentration measured at the nth sampling point, V0 is the volume of the receiving pool, C i is the drug mass concentration measured at the i-th (i=n-1) sampling point, V is the sampling volume, and A is the effective transdermal area.

[0042] The results are as follows Figure 3 , ionic liquid microemulsion has a good penetration-enhancing ability for model drugs. The drug penetration effect of ionic liquid microemulsion was compared with that of ionic liquid and phosphate buffer solution. Compared with pure ionic liquid and water, ionic liquid microemulsion has a higher drug permeability. Specifically, its penetration effect is 150 times higher than that of phosphate buffer solution and 1.6 times higher than that of pure ionic liquid.

[0043] Nile Red dye was dissolved in the ionic liquid microemulsion obtained in Example 2 of the present invention at a concentration of 1 mg / mL, and the mouse skin prepared by the previous method was frozen at -20°C for 12 hours, frozen sections were made, and the transdermal effect was observed under a fluorescence microscope. The results are as follows Figure 4 , the skin cross section showed the red color of Nile red, while the red fluorescence of the phosphate buffer solution group remained on the skin surface, which indicated that the ionic liquid microemulsion of the present invention could effectively promote the drug to penetrate the skin.

[0044] Example 9

[0045] Human immortalized keratinocytes were used to evaluate the cytotoxicity of the ionic liquid microemulsion obtained in Example 2 of the present invention. Human immortalized keratinocytes were cultured in DMEM complete medium. 100 μL of the cell suspension was added to a 96-well plate and incubated at 37°C for 24 h in a 5% CO2 atmosphere. After observing that the bottom of the 96-well plate was full of cells under a microscope, 0, 12.5, 25, 50, 100, 200, and 400 μg / mL of the ionic liquid microemulsion solution of Example 2 were added, incubated for 24 h, the culture medium was removed, and the cell activity was determined using the MTT method. The cell activity was calculated by the following formula:

[0046]

[0047] The results are as follows Figure 5 As shown, after human immortalized keratinocytes were incubated with the ionic liquid microemulsion solution with a concentration of 400 μg / ml for 24 hours, the cell survival rate was above 80%, indicating that the ionic liquid microemulsion had good biocompatibility.

Claims

1. An ionic liquid microemulsion, It is characterized in that The invention adopts a hydrophilic ionic liquid as the hydrophilic phase, oleic acid as the lipophilic phase, and is supplemented with a mixed emulsifier. The mixed emulsifier is polyoxyethylene 40 hydrogenated castor oil and diethylene glycol ethyl ether miscible in a mass ratio of 3:1-1:

3. In terms of mass percentage, the hydrophilic phase ratio is 10-30%, the lipophilic phase ratio is 3-20%, and the mixed emulsifier is 50%-80%, so as to construct an ionic liquid microemulsion.

2. The ionic liquid microemulsion according to claim 1, It is characterized in that The hydrophilic phase is choline lactate ionic liquid, choline acetate ionic liquid or the two are miscible in any proportion.

3. The ionic liquid microemulsion according to claim 2, It is characterized in that The molar ratio of lactic acid or acetic acid to choline in the ionic liquid is 1:2-2:

1.

4. The ionic liquid microemulsion according to claim 1, It is characterized in that Add the hydrophilic phase, lipophilic phase and mixed emulsifier into the reaction container in proportion and stir until clear and transparent to obtain the ionic liquid microemulsion.

5. Use of the ionic liquid microemulsion according to any one of claims 1 to 4 in a drug-carrying matrix for external preparations.

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