Retinoic acid-alcohol amine complex, method for preparing the same, and applications thereof

Abstract

The present invention relates to a retinoic acid-alcohol amine complex, which is composed of retinoic acid and an alcohol amine compound, is in a liquid form at room temperature, has good water solubility / water dilution resistance, and a skin penetration effect, overcomes the limitations in the formulation application field of retinoic acid compounds in the prior art, and is widely expected in therapeutic applications.

Description

Technical Field

[0001] This application claims the priority of a previous application filed with the Chinese National Intellectual Property on July 11, 2022, with the application number 202210853741.9 and the invention title "Retinoic Acid-Alcohol Amine Complex and Its Preparation Method and Application". The full text of the above application is incorporated herein by reference.

[0002] The present invention belongs to the field of pharmaceutical chemistry, and specifically relates to a retinoic acid-alcohol amine complex and its preparation method and application.

Background Art

[0003] Vitamin A and its metabolites all play important roles in the human body and are widely used in the treatment of various diseases. For example, retinoic acid (molecular formula: C 20 H 28 O2), an intermediate metabolite of vitamin A in vivo, mainly affects bone growth and promotes metabolic effects such as the proliferation, differentiation, and keratinolysis of epithelial cells. Retinoic acid is used in the treatment of diseases such as acne vulgaris, hyperpigmentation, photoaging of the skin, psoriasis, ichthyosis, lichen planus, pityriasis rubra pilaris, keratosis pilaris, squamous cell carcinoma, and melanoma. Oral retinoic acid is also used in the treatment of acute promyelocytic leukemia.

[0004] Retinoic acid is lipophilic and hardly soluble in water, so its solubility in the formulation and elution in vivo are poor, and it is limited as a therapeutic formulation. In addition, due to the barrier function of the skin stratum corneum, the amount of components that can pass through the barrier function in a normal topical retinoic acid formulation is small, and it is difficult to maintain a therapeutically effective concentration. On the other hand, when the dosage of retinoic acid is increased, inflammatory symptoms such as redness, tingling, and swelling will appear to some extent, resulting in significant skin irritation. Since the application of retinoic acid in the field of treating skin-related diseases is expected, it is necessary to develop a pharmaceutical form suitable for application to skin-related diseases.

Summary of the Invention

[0005] In order to improve the technical problems existing in the prior art, in a first aspect, the present invention provides a retinoic acid-alcohol amine complex composed of retinoic acid and an alcohol amine compound.

[0006] According to an embodiment of the present invention, the alcohol amine compound is selected from the following formula I:

[0007]

Chemical formula

[0008] Here, X is selected from alkyl groups of C 1-6 preferably -CH2-CH2-, -CH2-CH2-CH2- and

[0009]

Chemical formula

[0010] selected from, and R1 and R2 are each independently selected from H, C 1-6 alkyl group, C 1-6 alkyl group-OH.

[0011] According to an embodiment of the present invention, the formula I is selected from diethanolamine, triethanolamine, monoethanolamine (2-hydroxyethylamine), N-methyldiethanolamine, n-propanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, n-butanolamine, dibutanolamine, isobutanolamine.

[0012] According to an embodiment of the present invention, the molar ratio of the alcohol amine compound to retinoic acid is (1-100):1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, (1-10):1, and more preferably (1-5):1.

[0013] According to an embodiment of the present invention, the complex is a liquid at room temperature. In the complex, the retinoic acid may be partially or entirely in anionic form, and the alcoholamine may be partially or entirely in cationic form. In some embodiments, in the complex, a part of the retinoic acid exists in molecular form and / or a part of the alcoholamine compound exists in molecular form.

[0014] In some embodiments, in the complex, the retinoic acid is in the form of the following A - :

[0015]

Chemical formula

[0016] In some embodiments, in the complex, the alcoholamine compound is in the form of the following formula II B + :

[0017]

Chemical formula

[0018] In formula II, X’ is selected from alkyl groups of C 1-6 , preferably selected from -CH2-CH2-, -CH2-CH2-CH2- and

[0019]

Chemical formula

[0020] and R1 ’ , R2 ’ are each independently selected from H, C 1-6 alkyl group, C 1-6 alkyl group-OH.

[0021] According to an embodiment of the present invention, the formula II is selected from diethanolamine cation, triethanolamine cation, monoethanolamine cation (i.e., 2-hydroxyethylamine cation), N-methyldiethanolamine cation, n-propanolamine cation, isopropanolamine cation, diisopropanolamine cation, triisopropanolamine cation, n-butanolamine cation, dibutanolamine cation, isobutanolamine cation.

[0022] In some embodiments, the complex is [A - B + x wherein x can be selected from 1-10, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7.

[0023] In a second aspect, the present invention provides a method for preparing the complex, including a procedure obtained by reacting retinoic acid with the alcoholamine compound.

[0024] According to an embodiment of the present invention, the molar ratio of the alcoholamine compound to retinoic acid is (1-100):1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, (1-10):1, and more preferably, (1-5):1.

[0025] According to an embodiment of the present invention, the reaction reagent for the reaction can be water, or an organic solvent, or a mixed solvent of an organic solvent and water, and the organic solvent is selected from any one of ethanol, methanol and acetone, or a combination of two or more. Preferably, the organic solvent is ethanol.

[0026] According to an embodiment of the present invention, the volume ratio of the organic solvent to water in the mixed solvent is 5:95 to 95:5. Preferably, the volume ratio of the organic solvent to water in the mixed solvent is 40:60 to 95:5.​

[0027] According to an embodiment of the present invention, the reaction can be carried out by dry polishing.

[0028] According to an embodiment of the present invention, the total dosage ratio of the retinoic acid to the reaction reagent is 1 g: 5 - 150 mL, preferably 1 g: 5 - 20 mL.

[0029] According to an embodiment of the present invention, the preparation method includes the following steps: (1) Add a reaction reagent to the retinoic acid and stir to mix. (2) Add a reaction reagent to the alcoholamine compound and stir to dilute. (3) Add the dilution obtained in step (2) to the mixture obtained in step (1).

[0030] According to an embodiment of the present invention, in step (1), the dosage ratio of the retinoic acid to the reaction reagent is 1 g: 5 - 100 mL, preferably 1 g: 5 - 20 mL, and in step (2), the dosage ratio of the alcoholamine compound to the reaction reagent is 1 g: 0.5 - 50 mL, preferably 1 g: 0.5 - 5 mL, and more preferably 1 g: 0.5 - 1 mL.

[0031] According to an embodiment of the present invention, the preparation method also includes the steps of removing the reaction reagent and vacuum drying after the reaction is completed.

[0032] In a third aspect, the present invention provides a composition containing the retinoic acid - alcoholamine complex.

[0033] In a fourth aspect, the present invention provides the application of the retinoic acid - alcoholamine complex or the composition in the preparation of a formulation, and the formulation includes, but is not limited to, drugs, cosmetics, care products, and beauty products.

[0034] The agent is used for the treatment of skin-related diseases and non-skin tumors. Preferably, the agent is applied to the treatment of skin-related diseases, for example, it can be used for the treatment of diseases such as acne, hyperpigmentation, photoaging of the skin, psoriasis, ichthyosis, lichen planus, pityriasis rubra pilaris, keratosis pilaris, squamous cell carcinoma and melanoma. In some embodiments, the agent is applied to the treatment of non-skin tumors, for example, the treatment of acute promyelocytic leukemia, and can also be applied to gastric cancer, lung cancer, ovarian cancer, cervical cancer, neuroblastoma, glioma, etc.

[0035] According to an embodiment of the present invention, the preparation can be administered topically through the skin, for example, selected from creams, patches, ointments, cream preparations, gels and sprays, or can be administered orally (i.e., as an oral preparation), for example, selected from tablets, granules, capsules, oral liquid preparations, tablets, suspension mixtures, drops, etc. The preparation further includes a physiologically acceptable carrier (for example, a biocompatible material), for example, optionally, a surfactant, an excipient, a humectant, an emulsification promoter, a suspending aid, a salt or buffer for adjusting osmotic pressure, a coloring agent, a fragrance, a stabilizer, a bactericide, a preservative or other conventional adjuvants.

[0036] According to an embodiment of the present invention, the administration routes of the preparation include, but are not limited to, enteral administration or parenteral administration. Among them, the enteral administration can be oral administration, and the parenteral administration can be transdermal administration, etc.

Advantages of the Invention

[0037] The present invention unexpectedly finds that retinoic acid and alcohol amine form a complex in liquid form at room temperature, and has good water solubility / water dilution resistance and skin penetration effect, which overcomes the limitations in the formulation application field of retinoic acid compounds in the prior art, and thus can be widely expected in the therapeutic use. The preparation method adopted in this research institute does not require harsh reaction conditions, is simple and easy to execute, and is easy for quality control and scale-up production. In addition, the used solvent can be recycled and reused, which conforms to the concept of green chemistry.

Brief Description of the Drawings

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying out the Invention

[0039] The following further details the technical solution of the present invention in accordance with specific embodiments. It should be understood that the following embodiments are merely illustrative explanations and interpretations of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above content of the present invention are included in the protection scope intended by the present invention.

[0040] Unless otherwise stated, all raw materials and reagents used in the following examples are either commercially available or can be prepared by known methods.

[0041] Equipment and Measurement Conditions:

[0042]

Table 1

[0043] Unless otherwise stated, the percentage "%" in the following examples represents mass percentage.

[0044] Example 1 Preparation of Retinoic Acid - Diethanolamine Complex 1.1 Raw Materials and Reagents: Retinoic Acid (RA) (AR, Shanghai Aladdin Biochemical Technology Co., Ltd.), Diethanolamine (DEA) (AR, Sinopharm Chemical Reagent Co., Ltd.), Ethanol (AR, Sinopharm Chemical Reagent Co., Ltd.).

[0045] 1.2 Preparation Process of Retinoic Acid - Diethanolamine Complex 1.2.1 Preparation Method 1 Formulation

[0046]

Table 2

[0047] (1) Weighed retinoic acid according to the prescribed amount and put it into a round-bottom flask, added ethanol and stirred to mix. Retinoic acid could not be completely dissolved and showed a suspension state. Wrapped the round-bottom flask with aluminum foil to shield it from light.

[0048] (2) Weighed diethanolamine according to the prescribed amount, put it into a container wrapped with aluminum foil, added ethanol and stirred to dilute.

[0049] While stirring, the diethanolamine dilution solution obtained in procedure (2) was dropped into the mixed solution obtained in procedure (1), the container was washed with about 5 ml of ethanol, and then added to the flask together and stirred.

[0050] After the dropping was completed, the solution stopped being in a clear orange-red state and continued to be stirred for another 4 h.

[0051] Removal of the solvent by a rotary evaporator: The vacuum degree (indicated by the vacuum gauge) was set to -0.095 Mpa, and the temperature was increased by a program to prevent the boiling and scattering of ethanol. Rotary evaporation was carried out at 45 °C for 1 h, the temperature was raised to 50 °C and then rotary evaporation was carried out for another 1 h, and the temperature was raised to 60 °C and then rotary evaporation was carried out for another 2 h. A reddish-brown viscous liquid was obtained, which was suctioned while it was hot, and then vacuum dried in a vacuum drying oven at 60 °C for 48 h. The obtained sample was sealed and stored under light shielding.

[0052] 1.2.2 Preparation method two Prescription:

[0053]

Table 3

[0054] Process: Weighed retinoic acid according to the prescribed amount and put it into a round-bottom flask, added ethanol / water and stirred to mix. Retinoic acid could not be completely dissolved and showed a suspension state. Wrapped the round-bottom flask with aluminum foil to shield it from light.

[0055] Weighed diethanolamine according to the prescribed amount, put it into a container wrapped with aluminum foil, added ethanol / water, stirred, and diluted it.

[0056] While stirring, the diethanolamine dilution solution was dropped into the round-bottom flask containing the above-mentioned retinoic acid mixture. The container was washed with about 5 ml of ethanol / water and added to the flask together and stirred. After the dropping was completed, the solution stopped being in a clear orange-red state and continued to be stirred for another 4 h. The solvent was removed with a rotary evaporator. A reddish-brown viscous liquid was obtained, which was suctioned while it was hot and then vacuum-dried in a vacuum drying oven at 60 °C for 48 h. The obtained sample was sealed and stored under light-shielding.

[0057] 1.2.3 Preparation Method Three Prescription:

[0058]

Table 4

[0059] Process: Weighed diethanolamine according to the prescribed amount and put it into a round-bottom flask. The round-bottom flask was wrapped with aluminum foil to shield it from light.

[0060] Added the prescribed amount of water to the round-bottom flask and stirred until it became uniform. Weighed the prescribed amount of retinoic acid, divided the powder, and added it to the flask slowly while stirring. After the solution became clear, it was stirred for another 4 h. The solvent was removed with a rotary evaporator. A reddish-brown viscous liquid was obtained, which was suctioned while it was hot and then vacuum-dried in a vacuum drying oven at 60 °C for 48 h. The obtained sample was sealed and stored under light-shielding.

[0061] 1.2.4 Preparation Method Four Prescription:

[0062]

Table 5

[0063] Process: During the test process, attention was paid to light shielding. Retinoic acid was weighed according to the prescribed amount and placed in a crucible, and then the prescribed amount of diethanolamine was added. The two substances were slowly mixed with a thin milk stick until they became uniform. The crucible was heated with an electric heating jacket to maintain the temperature at 60 - 80 °C. It was continuously ground with stirring until it became a reddish-brown viscous liquid. While it was still hot, it was transferred to a light-shielding container, sealed after cooling, and stored.

[0064] 1.3 Preparation of Retinoic Acid - Diethanolamine Complexes with Different Ratios Referring to the preparation process in 1.2.1, complexes were prepared with different ratios of retinoic acid and diethanolamine (shown in the following table). The results showed that retinoic acid and diethanolamine could form complexes at a molar ratio of 2:1 - 10:1 (all were reddish-brown clear liquids at room temperature).

[0065]

Table 6

[0066] 1.4 Characterization of Retinoic Acid - Diethanolamine Complexes Experimental purpose: By measuring and analyzing the nuclear magnetic resonance hydrogen spectrum, infrared spectrum, and Raman spectrum of the starting materials and the retinoic acid - diethanolamine complexes, it was found that the substance formed between retinoic acid and diethanolamine was not a simple physical mixture, but intermolecular interactions occurred, and ionic bonds and hydrogen bonds existed, which constituted the chemical basis for the special physicochemical properties of the retinoic acid complexes.

[0067] 1.4.1 Nuclear Magnetic Resonance Hydrogen Spectrum (HNMR) As shown in Figures 1 - 3 and the following table, retinoic acid, diethanolamine, and the prepared retinoic acid - diethanolamine complex (2[DEA][RA]) were identified by nuclear magnetic resonance hydrogen spectrum.

[0068]

Table 7

[0069] As a result, in the 1H NMR of 2[DEA][RA], the active hydrogen of retinoic acid disappeared, suggesting that an interaction between retinoic acid and diethanolamine occurred. The chemical shift of the ortho-position hydrogen atom of the carboxyl group of retinoic acid shifted to the high magnetic field side from 7.02 to 6.78, suggesting that retinoic acid was anionized as a proton donor in the complex system, and the charge center was the carboxylic acid oxygen atom. The two pairs of methylene hydrogens of diethanolamine showed a chemical shift to the low magnetic field, from 2.58 to 2.76 and from 3.46 to 3.56, suggesting that diethanolamine was cationized as a proton acceptor in the complex system, that is, the lone pair of electrons on the N atom was combined with a free proton, and the charge center was the N atom.

[0070] Figures 13 - 14 show the 1H NMR spectra of the complexes 2.5[DEA][RA] and 3[DEA][RA], respectively, and characteristic chemical shifts similar to those of 2[DEA][RA] occurred. As described above, similar intermolecular interactions also occur between retinoic acid and a higher ratio of diethanolamine, and a stable liquid complex can be formed at room temperature.

[0071] 1.4.2 Infrared Spectrum (IR) As a result of the IR identification of retinoic acid, diethanolamine, and the obtained 2[DEA][RA] (shown in Figure 4), compared with diethanolamine, the peak shift of diethanolamine in 2[DEA][RA] was not obvious, and compared with retinoic acid, the characteristic vibration frequency of the C=O double bond of retinoic acid in 2[DEA][RA] (1681.57 cm-1) shifted to a lower wave number, suggesting that there was an interaction between retinoic acid and diethanolamine molecules.

[0072] Complexes with different ratios were prepared at a molar ratio of RA:DEA = 1:2, 1:2.5, 1:3, and 1:4. The infrared spectra of each complex were consistent (shown in Figure 5), and since the characteristic vibration frequency of all C=O double bonds (1682 cm-1) shifted to a lower wavenumber, it was suggested that there was an interaction between retinoic acid and diethanolamine molecules.

[0073] 1.4.3 Raman Spectrum As a result of identifying the Raman spectra of retinoic acid, diethanolamine, and 2[DEA][RA] obtained from the preparation (shown in Figure 6), the Raman spectrum of 2[DEA][RA] was clearly different from that of diethanolamine, and as the difference could be seen when compared with retinoic acid, the characteristic vibration frequency of the C=C double bond (1574.72 cm -1 ) shifted to a higher wavenumber of 1589.19 cm -1 , suggesting that an interaction occurred between retinoic acid and diethanolamine.

[0074] Preparation of Retinoic Acid-Triethanolamine Complex Referring to the preparation process in 1.2 of Example 1, diethanolamine was replaced with triethanolamine, and complexes were prepared with different ratios of retinoic acid and triethanolamine (shown in the table below). As a result, complexes could be formed when the molar ratio of retinoic acid to triethanolamine was 1:8, 1:9, or 1:10, but when the molar ratio was 1:(1 - 7), it was difficult to form a complex in liquid form at room temperature (see Figure 15).

[0075]

Table 8

[0076] Examination of General Physicochemical Properties of Retinoic Acid-Alcoholamine Complexes Regarding 2[DEA][RA] obtained from the preparation in 1.2.1, the following physicochemical properties were examined.

[0077] 1.5 Moisture and Residual Solvents As a result of measuring 2[DEA][RA] of three batches with a Karl Fischer moisture meter, it was found that moisture and residual solvents in the prepared composite could be easily removed.

[0078]

Table 9

[0079] 1.6 Dynamic moisture sorption (DVS) In the DVS results (see Figure 7), it was shown that 2[DEA][RA] has a certain degree of hygroscopicity. In the PLM results (see Figure 8), it was shown that there are no crystal particles in 2[DEA][RA] before and after DVS, the composite has a low risk of precipitating retinoic acid at atmospheric humidity, and its liquid form can be stably maintained.

[0080] 1.7 Differential scanning calorimetry (DSC) In the DSC results (see Figure 9), since 2[DEA][RA] does not show an exothermic or endothermic signal in the range of -25°C to 40°C, it was shown that the composite has no freezing point within this temperature range. In the mDSC results (see Figure 10), no glass transition point of the composite was observed in the range of -25°C to 25°C. This indicates that the composite has no risk of solidifying and precipitating within this temperature range and can stably maintain its liquid form.

[0081] Water solubility / water dilution resistance of retinoic acid complex 1.8 Experimental purpose In the section on retinoic acid in the second part of the Chinese Pharmacopoeia (2020 Edition), it is described that retinoic acid is extremely insoluble in water. According to the literature, the solubility of retinoic acid in water is only 1.06*10 -6(Ascenso A, Guedes R, Bernardino R, et al. Complexation and full characterization of the tretinoin and dimethyl-β-cyclodextrin complex. AAPS PharmSciTech. 2011;12(2):553-563. doi:10.1208 / s12249-011-9612-3). The poor solubility of retinoic acid poses a very significant challenge to the formulation process. On the other hand, the retinoic acid complex has a certain degree of water solubility, which is advantageous for the preparation of formulations.

[0082] 1.9 Test process 2[DEA][RA] and different ratios of water were accurately weighed, vortexed and mixed, and the properties of the complexes with different water contents were observed. After the water content exceeded 90%, while continuously adding small amounts of water using a microsyringe until the solution became turbid, it was vortexed and mixed. The critical water content of the obtained complex was weighed and calculated.

[0083] 1.10 Results and discussion As shown in Figure 11, within the proportional range of water content from 0 to 91.4% (w / w), 2[DEA][RA] is mutually soluble with water (when the water content ≤ 90%, the liquid in the flask is clear and transparent). When the water ratio is too high (>91.4%), the hydrogen bonds in water break the complex system, and solid retinoic acid precipitates (the flask with a water content of 91.4% shows a turbid state). The results of testing the water dilution resistance of complexes with other molar ratios are as follows in the table. With the increase in the DEA ratio, the water dilution resistance of the retinoic acid - diethanolamine complex increases.

[0084]

Table 10

[0085] Induced crystallization test of retinoic acid complex 1.11 Test purpose In the practice of chemical synthesis processes, in the recrystallization process of compounds, amorphous crystals or supercooled liquids are often formed, and their appearance forms often show a glassy or transparent oily state. This is similar to the composite properties of the present invention. However, this state is unstable and will change to a stable crystalline state when external conditions change or when induced by crystal seeds. Therefore, in order to eliminate this possibility and further demonstrate that the composite prepared according to the present invention has a stable liquid form, a series of induction challenge tests to obtain the solid form of the composite were carried out by various means to promote crystallization, such as volatility tests, stirring tests, cooling tests, etc. If the solid form cannot be obtained, it is considered that the liquid form of the obtained composite is its stable form.

[0086] 1.12 Volatility Test In different solvent systems, it was investigated whether there was the generation of solid substances after the solvent was completely volatilized with or without polymers and at different temperatures for the composite. In this case, adding polymers is to add "crystal nuclei" to the system and compare the presence or absence of the influence of crystal nuclei. Different temperatures affect the volatilization rate of the solvent and the crystallization behavior of substances.

[0087] Dissolve about 80 mg of 2[DEA][RA] in the corresponding solvent to obtain a clear solution, and divide it into four equal parts. Here, with the polymer as the "crystal nucleus", after adding no polymer, polymer B, or polymer C, it was volatilized at 5 °C and 50 °C for about 4 days, and the sample state was observed. No solid matter was observed except for the added polymers. The results are shown in the following table.

[0088]

Table 11

[0089] 1.13 Stirring Test At room temperature (~22 °C), add 0.3 mL of the corresponding solvent to about 20 mg of 2[DEA][RA], stir at the corresponding temperature for 3 days, and then check whether a clear solution is obtained, or the formation of oil is observed, and no solid matter is obtained. The results are shown in the following table.

[0090]

Table 12

[0091] 1.14 Cooling Test At 50 °C, about 40 mg of 2[DEA][RA] was dissolved in the corresponding solvent. After obtaining a clear solution, it was divided into two portions, cooled according to the corresponding procedure, and equilibrated at low temperature for 3 days. No solid was obtained in either case. The results are shown in the table below.

[0092]

Table 13

[0093] 1.15 Liquid Nitrogen Freezing Test Using a weighing spoon, about 50 mg of 2[DEA][RA] was scooped up, and the sample in the spoon was placed into liquid nitrogen (a reddish-brown transparent liquid before freezing). After freezing for about 1 minute, it was taken out, and a reddish-brown transparent solid (hard and brittle) was obtained. However, after reheating (room temperature: ~22 °C), it melted immediately (returned to a reddish-brown transparent liquid), and no solid was observed. The test process is shown in Figure 12.

[0094] 1.16 Poor Solvent Addition Test An appropriate volume of the good solvent was added to an appropriate amount of 2[DEA][RA] to obtain a clear solution. When there were two types of corresponding poor solvents, the clear solution was divided into two equal portions. Until a solid precipitated, at room temperature (~22 °C), the poor solvent was slowly added to the clear solution while stirring (the maximum volume of poor solvent added was 1.5 mL). When a solid precipitated, the addition of the poor solvent was stopped, and it was stirred at room temperature for about 4 days to see if a clear solution was obtained or if the formation of oil was observed, and no solid was obtained. The results are shown in the table below.

[0095]

Table 14

[0096] 1.17 Summary of Induced Crystallization Test Starting from the retinoic acid - diethanolamine complex, a total of 49 induction crystallization tests (including volatilization, stirring, cooling, addition of poor solvent, and liquid nitrogen freezing) were carried out. The reaction solvents included single solvents or combinations of two - component solvents in various categories, and the reaction temperature covered - 20°C to 50°C (the liquid nitrogen freezing test temperature was - 196°C). In all tests, no solids were obtained. As described above, it was suggested that the retinoic acid - diethanolamine complex was difficult to exist in solid form, that is, its liquid form at room temperature was stable.

[0097] Study on the penetration - enhancing effect of retinoic acid complex 1.18 Comparison of the penetration - enhancing effects of retinoic acid - diethanolamine complexes with different concentrations 2[DEA][RA] was mixed with different amounts of water respectively to prepare complex solutions containing 10%, 20%, and 40% (w / w). The skin penetration effect of retinoic acid was studied by in vitro skin permeation test. The result showed that the skin penetration effect of retinoic acid increased with the increase of the water content.

[0098]

Table 15

[0099] 1.19 Complex skin permeation test 1.19.1 Preparation of complex solution A certain amount of the complex 2[DEA][RA] was weighed and dissolved in purified water (to make the concentration of the complex in the aqueous solution 10% (w / w)), stirred until it became homogeneous, vortexed for 3 min, and the samples were uniformly mixed. The prepared aqueous solution concentration of the retinoic - acid - based complex was made 5.88% (w / w).

[0100] 1.19.2 Preparation of retinoic acid cream 20 g of o / w matrix was prepared according to the following formulation process.

[0101]

Table 16

[0102] process: The water phase material was weighed according to the recipe and mixed uniformly. The oil phase material was weighed according to the recipe, heated to 80°C, melted, and mixed uniformly. The water phase was added while hot, and homogenized for 2 minutes using a high-shear dispersion emulsifier at 20,000 rpm, and cooled to room temperature.

[0103] 1.19.3 Skin Permeation Test Basic Information

[0104] [Table 17]

[0105] 1.19.4 Testing Process: (1) Test preparation: Prepare the sample and receiving solution in advance. Prepare a pigskin of appropriate size, preferably one with few pores, and weigh it so that the weight difference is 0.05g or less. (2) Equilibration of the skin: The Franz dispersion cell was assembled and the skin was carefully and firmly fixed. The receiving liquid was added, eliminating air bubbles, and ensuring sufficient contact between the receiving liquid and the lower surface of the skin. After the temperature of the diffuser reached the set temperature, the skin was allowed to equilibrate for 1 h. The TEWL value was measured and was 20 g / m 2 h or less. (3) Test: Approximately 0.5ml was administered, and the cream was evenly applied and thoroughly contacted with the skin. The actual administered amount was obtained by measuring with a balance. (4) Sampling: The test was terminated after 6 hours, and the receiving fluid and skin were collected and treated.

[0106] 1.19.5 Sample processing (1) Receiving liquid: After the skin permeation test was completed, 1.5 ml of the receiving solution was aspirated and centrifuged at 12,000 rpm for 15 min, and the supernatant was measured by HPLC.

[0107] (2) Skin extract: After the skin penetration test, the sample on the skin surface was wiped off with clean paper, and the surface was rinsed with more than 5 ml of PBS. The skin was gently removed and the moisture on both sides was absorbed with filter paper. The upper surface of the skin was pasted 6 times with adhesive tape to remove the stratum corneum. Next, the upper surface of the skin was carefully wiped with a cotton ball dipped in ethanol.

[0108] After cutting off the pressing edges around the skin, the skin was cut into small pieces and placed in a 5 ml centrifuge tube. 1 ml of methanol was added so that the skin fragments were completely immersed. Extraction was performed with ultrasonic waves for 60 min. After the extraction with ultrasonic waves was completed, 0.8 ml of the extraction solution was absorbed, centrifuged at 12000 rpm for 15 minutes, and the supernatant was measured by HPLC.

[0109] 1.19.6 Test Results (1) HPLC Measurement Results of Skin Penetration Test Retinoic acid could not be detected from the receiving solution. The results of measuring the retinoic acid retained in the skin are as follows.

[0110]

Table 18

[0111] As shown in the above table, the skin retention amount of the 2[DEA][RA] aqueous solution group was significantly higher than that of the RA cream group, suggesting that 2[DEA][RA] has an obvious penetration promoting effect.

[0112] (2) Skin Staining Condition after Skin Penetration Test (Removal of Stratum Corneum by Adhesion and Wiping with Ethanol) After the skin penetration test, the skin surface was washed, the stratum corneum was removed with an adhesive tape, wiped with ethanol, and the sample remaining on the skin surface was removed as much as possible. As a result of the test, compared with the RA cream group, the skin of the 2[DEA][RA] aqueous solution group was clearly stained, showing the characteristic yellow color of retinoic acid. It was suggested that 2[DEA][RA] significantly improved the skin penetration effect of retinoic acid. It should be particularly noted that the actual use concentrations (0.025%, 0.05%, 0.1%) of the retinoic acid preparation are much lower than that of the test sample (5.88%). Therefore, there is no need to worry about the side effect of skin staining during actual use. The purpose of selecting a high-concentration sample in this test is to meet the requirements of the quantitative limit of HPLC and to more easily demonstrate the penetration-enhancing effect of 2[DEA][RA].

[0113] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A retinoic acid - alcohol amine complex, characterized by comprising retinoic acid and an alcohol amine compound.

2. The complex according to claim 1, wherein the alcohol amine compound is selected from the following formula I: [Chemical 1] Here, X is selected from alkyl groups of C 1-6 and is preferably -CH 2 -CH 2 -, -CH 2 -CH 2 -CH 2 - and [Chemical 2] selected from, R 1 , R 2 are each independently H, C 1-6 alkyl group, C 1-6 alkyl group-OH, and preferably, Formula I is selected from diethanolamine, triethanolamine, monoethanolamine (2-hydroxyethylamine), N-methyldiethanolamine, n-propanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, n-butanolamine, dibutanolamine, isobutanolamine.

3. The complex according to claim 1, wherein the molar ratio of the alcohol amine compound to retinoic acid is (1 - 100):1, for example, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, (1 - 10):1, and more preferably (1 - 5):

1.

4. The complex according to claim 1, wherein the complex is liquid at room temperature.

5. The complex according to claim 1, wherein in the complex, the retinoic acid may exist partially or entirely in anionic form, and the alcohol amine may exist partially or entirely in cationic form.

6. The retinoic acid is in the following form [A - , and the complex according to claim 5 is characterized in that it exists in this form: 【Chemical Formula 3】 。

7. The alcoholamine compound is represented by the following formula II B + The complex according to claim 5, characterized in that it is present in the form of 【Chemical Formula 4】 In the formula II above, X’ is C 1-6 selected from alkyl groups of 2 preferably -CH 2 -CH 2 -CH 2 -CH 2 - and 【Chemical Formula 5】 selected from, R 1 ’ , R 2 ’ each independently is H, C 1-6 alkyl group, C 1-6 alkyl group-OH, and is selected from Preferably, the formula II is selected from diethanolamine cation, triethanolamine cation, monoethanolamine cation, N - methyldiethanolamine cation, n - propanolamine cation, isopropanolamine cation, diisopropanolamine cation, triisopropanolamine cation, n - butanolamine cation, dibutanolamine cation, isobutanolamine cation.

8. A method for preparing the complex according to any one of claims 1 - 7, comprising the following procedure: Obtained by reacting retinoic acid with the alcohol amine compound, preferably, the molar ratio of the alcohol amine compound to retinoic acid is (1 - 100):

1.

9. A composition, characterized by comprising the retinoic acid - alcohol amine complex according to any one of claims 1 - 7.

10. The application of the retinoic acid - alcohol amine complex according to any one of claims 1 - 7, or the composition according to claim 9, in the preparation of a medicament for treating skin - related diseases or non - skin tumors, preferably, the medicament is used for the treatment of skin - related diseases.

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