New crystal form of acetyl hexapeptide-8 as well as preparation method and application thereof

Abstract

The invention relates to the technical field of crystal forms, in particular to a novel crystal form of acetyl hexapeptide-8 as well as a preparation method and application thereof. The invention provides three new crystal forms of acetyl hexapeptide-8, namely a crystal form C, a crystal form D and a crystal form E. The crystal form is excellent in stability, the stability of the oil-soluble acetyl hexapeptide-8 prepared from the acetyl hexapeptide-8 crystal forms C, D and E is obviously better than that of the oil-soluble acetyl hexapeptide-8 prepared from acetyl hexapeptide-8 freeze-dried powder and the acetyl hexapeptide-8 crystal form B, and the oil-soluble acetyl hexapeptide-8 can be suitable for an oil-soluble system.

Description

Technical Field

[0001] This invention relates to the field of crystal form technology, and in particular to a novel crystal form of acetyl hexapeptide-8, its preparation method, and its application. Background Technology

[0002] Acetyl hexapeptide-8 (Ac-Glu-Glu-Met-Gln-Arg-Arg-NH2), also known as acetyl hexapeptide-3 or acereline, is a hexapeptide fragment of the synaptosome-associated protein SNAP-25. It competitively interferes with the assembly of the SNARE complex, inhibiting the release of the neurotransmitter acetylcholine, thereby reducing muscle contraction and easing expression lines. Due to its small molecular weight, acetyl hexapeptide-8 can be absorbed transdermally, and its mechanism of action is similar to that of botulinum toxin, hence it is also known as "topical botulinum toxin." Acetyl hexapeptide-8 is listed in the "Catalogue of Used Cosmetic Ingredients" (2021 edition), and over 140,000 cosmetic products contain this ingredient, making it the most numerous peptide ingredient.

[0003] In recent years, the concept of "oil-based skincare" has become popular, with the total transaction volume of essential oil products on mainstream online platforms reaching 9.5 billion yuan. Among them, facial essential oils are the core category, with sales reaching 7.3 billion yuan, while body essential oil sales have also grown rapidly to 1.09 billion yuan. In addition to the high permeability and soothing plant active ingredients brought by oils, essential oils need to introduce new efficacy. Anti-wrinkle peptides are particularly suitable for the use of essential oils, such as acetyl hexapeptide-8, conopeptide, snake venom-like peptides, and acetyl tetrapeptide-5.

[0004] Currently, acetyl hexapeptide-8 lyophilized powder is insoluble in oils and unstable in the oil phase, which limits its application in cosmetics such as facial oils, makeup remover oils, and makeup foundations. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a new crystal form of acetyl hexapeptide-8, its preparation method and application, wherein the prepared new crystal form of acetyl hexapeptide-8 has high solubility and good stability in the oil phase.

[0006] To achieve the above objective, the present invention provides a crystal form C of acetyl hexapeptide-8, whose X-ray powder diffraction pattern shows diffraction peaks at positions of 2θ ± 0.2°, wherein 2θ includes: 4.478°, 6.458°, 17.740°, 19.233°, 20.227°, 23.034°, and 26.947°.

[0007] Furthermore, the 2θ includes: 4.478°, 6.458°, 8.104°, 12.902°, 13.363°, 13.936°, 14.334°, 15.374°, 16.383°, 17.740°, 18.454°, 19.233°, 20.227°, 20.93°, 22.72°, 23.034°, 23.958°, 25.869°, 26.660°, 26.947°, 28.327°, 32.867°, 33.279°, 34.128°, 34.66°, 38.67°, 43.190°, and 48.01°.

[0008] Furthermore, the 2θ is shown in Table 3.

[0009] Specifically, the X-ray powder diffraction pattern of crystal form C of acetyl hexapeptide-8 described in this invention is as follows: Figure 5 As shown.

[0010] Specifically, the DSC spectrum of crystalline form C of acetyl hexapeptide-8 described in this invention is as follows: Figure 6 As shown, by Figure 6 It can be seen that the crystal form C has an endothermic peak at 255.1±2℃.

[0011] In this invention, the 2θ values ​​of X-ray powder diffraction patterns may vary slightly between machines or samples, with differences of approximately 0.2 units or 0.1 units. Therefore, the values ​​cited should not be interpreted as absolute values. Similarly, it should be understood that peak heights may also vary by approximately 5 units, 4 units, 3 units, 2 units, or 1 unit. Therefore, the XRPD trace intensities included in this invention are illustrative and not intended for absolute comparison.

[0012] The present invention also provides a method for preparing the crystal form C of the above-mentioned acetyl hexapeptide-8, comprising the following steps:

[0013] An aqueous solution of acetyl hexapeptide-8 was contacted with isopropanol, and crystals were precipitated to obtain acetyl hexapeptide-8 crystal form C.

[0014] The concentration of the aqueous solution of acetyl hexapeptide-8 is preferably 50-500 g / L, more preferably 100-200 g / L.

[0015] The volume ratio of the aqueous solution of acetyl hexapeptide-8 to isopropanol is preferably 1:(2~5), more preferably 1:(2~3).

[0016] Preferably, isopropanol is added to an aqueous solution of acetyl hexapeptide-8. The method of addition is not particularly limited in this invention, and includes, but is not limited to, dropwise addition, flow addition, etc. Flow addition is preferred. The flow addition rate is preferably 40-60 mL / h.

[0017] The preferred temperature for contacting the aqueous solution of acetyl hexapeptide-8 with isopropanol is 25-35°C.

[0018] The crystallization temperature is preferably 5~20℃, more preferably 8~14℃. The crystallization time is preferably 3~10h, more preferably 4~8h.

[0019] Preferably, the system temperature is reduced to the crystallization temperature at a cooling rate of 3~10℃ / h. In some specific embodiments, the system temperature is reduced to the crystallization temperature at a cooling rate of 6~10℃ / h, wherein the cooling rate can be 6, 7, 8, 9, or 10℃ / h.

[0020] After crystallization, the crystals are washed with isopropanol and dried to obtain acetyl hexapeptide-8 crystal form C.

[0021] The drying process includes, but is not limited to, vacuum drying. The vacuum drying temperature is preferably 30~70℃, more preferably 40~60℃, and for example, it can be 40, 50 or 60℃.

[0022] The present invention provides a crystal form D of acetyl hexapeptide-8, whose X-ray powder diffraction pattern shows diffraction peaks at 2θ ± 0.2°, wherein 2θ includes: 6.887°, 13.764°, 19.284°, 20.141°, 20.603° and 23.233°.

[0023] Furthermore, the 2θ includes: 6.887°, 13.764°, 15.389°, 18.190°, 18.835°, 19.284°, 20.141°, 20.603°, 21.783°, 22.834°, 23.233°, 23.647°, 24.152°, 25.620°, 26.483°, 27.522°, 29.76°, and 34.114°.

[0024] Furthermore, the 2θ is shown in Table 4.

[0025] Specifically, the X-ray powder diffraction pattern of crystal form D of acetyl hexapeptide-8 described in this invention is as follows: Figure 7 As shown.

[0026] Specifically, the DSC spectrum of crystal form D of acetyl hexapeptide-8 described in this invention is as follows: Figure 8 As shown, by Figure 8It can be seen that the crystal form D has endothermic peaks at 248.8±2℃ and 255.5±2℃.

[0027] This invention provides a method for preparing crystal form D of the above-mentioned acetyl hexapeptide-8, comprising the following steps:

[0028] An aqueous solution of acetyl hexapeptide-8 was contacted with N,N-dimethylformamide (DMF) to crystallize and obtain acetyl hexapeptide-8 crystal form D.

[0029] The concentration of the aqueous solution of acetyl hexapeptide-8 is preferably 50-500 g / L, more preferably 100-200 g / L.

[0030] The volume ratio of the aqueous solution of acetyl hexapeptide-8 to DMF is preferably 1:(2~5), more preferably 1:(2~3).

[0031] Preferably, DMF is added to an aqueous solution of acetyl hexapeptide-8. The method of addition is not particularly limited in this invention, and includes, but is not limited to, dropwise addition, flow addition, etc. Flow addition is preferred. The flow addition rate is preferably 40-60 mL / h.

[0032] The preferred temperature for contacting the aqueous solution of acetyl hexapeptide-8 with DMF is 25-35°C.

[0033] The crystallization temperature is preferably 5~20℃, more preferably 8~14℃. The crystallization time is preferably 3~10h, more preferably 4~8h.

[0034] Preferably, the system temperature is reduced to the crystallization temperature at a cooling rate of 3~10℃ / h. In some specific embodiments, the system temperature is reduced to the crystallization temperature at a cooling rate of 6~10℃ / h, wherein the cooling rate can be 6, 7, 8, 9, or 10℃ / h.

[0035] After crystallization, the crystals are washed with DMF and dried to obtain acetyl hexapeptide-8 crystal form D.

[0036] The drying process includes, but is not limited to, vacuum drying. The vacuum drying temperature is preferably 30~70℃, more preferably 40~60℃, and for example, it can be 40, 50 or 60℃.

[0037] This invention provides a crystal form E of acetyl hexapeptide-8, whose X-ray powder diffraction pattern shows diffraction peaks at 2θ ± 0.2°, wherein 2θ includes: 5.02°, 6.545°, 12.092°, 15.43°, 17.717°, 18.758°, 19.556°, 21.380°, and 23.953°.

[0038] Furthermore, the 2θ includes: 5.02°, 6.545°, 9.253°, 11.141°, 12.092°, 15.43°, 17.717°, 18.758°, 19.556°, 20.79°, 21.380°, 21.62°, 23.953°, 26.225°, 28.46°, and 30.518°.

[0039] Furthermore, the 2θ is shown in Table 5.

[0040] Specifically, the X-ray powder diffraction pattern of crystal form E of acetyl hexapeptide-8 described in this invention is as follows: Figure 9 As shown.

[0041] Specifically, the DSC spectrum of acetyl hexapeptide-8 in crystal form E of the present invention is as follows: Figure 10 As shown, by Figure 10 It can be seen that the crystal form E has endothermic peaks at 250.5±2℃ and 255.7±2℃.

[0042] This invention provides a method for preparing crystal form E of the above-mentioned acetyl hexapeptide-8, comprising the following steps:

[0043] An aqueous solution of acetyl hexapeptide-8 was contacted with 1,4-dioxane to crystallize and obtain acetyl hexapeptide-8 crystal form E.

[0044] The concentration of the aqueous solution of acetyl hexapeptide-8 is preferably 50-500 g / L, more preferably 100-200 g / L.

[0045] The volume ratio of the aqueous solution of acetyl hexapeptide-8 to 1,4-dioxane is preferably 1:(2~5), more preferably 1:(2~3).

[0046] Preferably, 1,4-dioxane is added to the aqueous solution of acetyl hexapeptide-8. The method of addition is not particularly limited in this invention, and includes, but is not limited to, dropwise addition, flow addition, etc. Flow addition is preferred. The flow addition rate is preferably 40-60 mL / h.

[0047] The preferred temperature for contacting the aqueous solution of acetyl hexapeptide-8 with 1,4-dioxane is 25-35°C.

[0048] The crystallization temperature is preferably 5~20℃, more preferably 8~14℃. The crystallization time is preferably 3~10h, more preferably 4~8h.

[0049] Preferably, the system temperature is reduced to the crystallization temperature at a cooling rate of 3~10℃ / h. In some specific embodiments, the system temperature is reduced to the crystallization temperature at a cooling rate of 6~10℃ / h, wherein the cooling rate can be 6, 7, 8, 9, or 10℃ / h.

[0050] After crystallization, the crystals are washed with 1,4-dioxane and dried to obtain acetyl hexapeptide-8 crystal form E.

[0051] The drying process includes, but is not limited to, vacuum drying. The vacuum drying temperature is preferably 30~70℃, more preferably 40~60℃, and for example, it can be 40, 50 or 60℃.

[0052] The crystal forms C, D, and E of the acetyl hexapeptide-8 prepared in this invention exhibit high solubility and good stability in a basic reverse micelle microemulsion system.

[0053] Based on this, the present invention provides the application of the crystal form C, crystal form D and / or crystal form E of acetyl hexapeptide-8 in the preparation of oil-soluble cosmetics.

[0054] The dosage form of the oil-soluble cosmetic is not specifically limited in this invention and can be any oil-soluble cosmetic well known to those skilled in the art, including but not limited to one or more of ointments, water-in-oil emulsions, anhydrous pure oils, gels, and aerosols.

[0055] In some specific embodiments, the oil-soluble cosmetics include one or more of the following: essential oils, makeup remover oils, makeup foundations, sunscreen oils, sunscreen sprays, moisturizing sprays, face creams, massage creams, facial cleansers, and lipsticks.

[0056] Based on this, the present invention provides an oil-soluble cosmetic comprising the crystal form C, crystal form D and / or crystal form E of acetyl hexapeptide-8, and an oil-soluble excipient.

[0057] The oil-soluble excipients may include oils, such as triglycerides, fatty alcohols, wax esters, etc., such as coconut oil (containing 50% lauric acid), olive oil (containing 82.5% stearic acid), almond oil (containing 70% oleic acid), etc.; they may also include wax excipients, such as lanolin, jojoba oil (containing long-chain unsaturated fatty acids), etc., which can play a moisturizing and stabilizing role; they may also include fatty acids, such as palmitic acid, oleic acid, linoleic acid, etc.

[0058] In addition to oil-soluble excipients, the aforementioned oil-soluble cosmetics may also include functional ingredients, such as whitening, moisturizing, and antioxidant ingredients.

[0059] In some specific embodiments, the oil-soluble adjuvants include polyglycerol-2 isostearate, isohexadecane, and 1,2-hexanediol.

[0060] The experimental results show that the oil-soluble peptide acetyl hexapeptide-8 prepared from the crystal forms C, D, and E of acetyl hexapeptide-8 provided by the present invention has a content of 80%~85% in the accelerated content change test at 45℃, and its stability is higher than that of lyophilized acetyl hexapeptide-8 powder and other crystal forms.

[0061] In some specific embodiments, the present invention provides a reverse micelle microemulsion system that can be dispersed in a variety of vegetable oils, including the crystal form C, crystal form D and / or crystal form E of acetyl hexapeptide-8, and the oil-soluble excipients mentioned above.

[0062] Compared with existing technologies, this invention provides three new crystal forms of acetyl hexapeptide-8: crystal form C, crystal form D, and crystal form E. These crystal forms exhibit excellent stability. The oil-soluble acetyl hexapeptide-8 prepared using crystal forms C, D, and E shows significantly better stability than the lyophilized acetyl hexapeptide-8 powder and the oil-soluble acetyl hexapeptide-8 prepared using crystal form B, making it suitable for oil-soluble systems. Attached Figure Description

[0063] Figure 1 X-ray powder diffraction pattern of acetyl hexapeptide-8 crystal form B prepared in Example 1;

[0064] Figure 2 The DSC spectrum of acetyl hexapeptide-8 crystal form B prepared in Example 1;

[0065] Figure 3 The X-ray powder diffraction pattern of acetyl hexapeptide-8 crystal form B prepared in Example 2;

[0066] Figure 4 The DSC spectrum of acetyl hexapeptide-8 crystal form B prepared in Example 2;

[0067] Figure 5 X-ray powder diffraction pattern of acetyl hexapeptide-8 crystal form C prepared in Example 3;

[0068] Figure 6 The DSC pattern of acetyl hexapeptide-8 crystal form C prepared in Example 3;

[0069] Figure 7 The X-ray powder diffraction pattern of acetyl hexapeptide-8 crystal form D prepared in Example 4;

[0070] Figure 8The DSC pattern of acetyl hexapeptide-8 crystal form D prepared in Example 4;

[0071] Figure 9 The X-ray powder diffraction pattern of acetyl hexapeptide-8 crystal form E prepared in Example 5;

[0072] Figure 10 The DSC spectrum of acetyl hexapeptide-8 crystal form E prepared in Example 5;

[0073] Figure 11 The graph shows the content changes of oil-soluble acetyl hexapeptide-8 crystals C, D, and E under accelerated conditions at 45℃. Detailed Implementation

[0074] To further illustrate the present invention, a detailed description is provided below with reference to embodiments. However, it should be understood that these descriptions are merely for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0075] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0076] In the following examples, the lyophilized acetyl hexapeptide-8 powder was prepared in-house, but it can also be obtained commercially.

[0077] Polyglycerol-2 isostearate was purchased from Cosfa (Guangzhou);

[0078] Isohexadecane was purchased from Guangzhou Hengtao;

[0079] 1,2-Pentanediol and 1,2-Hexanediol were purchased from Ashland;

[0080] The remaining reagents were purchased from Maclean's.

[0081] Example 1

[0082] Prepare 50 mL of 133 g / L acetyl hexapeptide-8 aqueous solution, stir continuously at 32 °C and 150 rpm, add 2.5 times the volume of acetone at a rate of 50 mL / h, and after the addition is completed, cool down to 12 °C at a rate of 8 °C per hour to crystallize for 6 h. After filtering and washing the powder with an appropriate amount of acetone, dry under vacuum at 50 °C until the weight is constant, with a yield of 90.8%.

[0083] The crystal powder was subjected to X-ray powder diffraction analysis using an Ultima IV instrument (equipped with a Cu K-β filter). The X-ray tube voltage was 40 kV, the X-ray tube current was 40 mA, the scanning range was 3-60° (2θ), and the step size was 0.0200°. Figure 1As shown in Table 1, the obtained crystal form exhibits characteristic peaks at 2θ = 5.469°, 8.726°, 10.925°, 16.357°, 19.119°, 19.465°, 21.915°, and 24.919°, and is named crystal form B. Simultaneously, the thermal effect of the crystal powder during the melting process was measured using a differential calorimeter (DSC). Figure 2 The data shows an endothermic peak at 265.8℃.

[0084] Table 1

[0085]

[0086]

[0087] Example 2

[0088] Prepare 50 mL of 160 g / L acetyl hexapeptide-8 aqueous solution, stir continuously at 28 °C and 180 rpm, add 2 times the volume of tetrahydrofuran to it at a rate of 40 mL / h, and after the addition is completed, cool down to 10 °C at a rate of 7 °C per hour to crystallize for 6 h. After filtering out an appropriate amount of tetrahydrofuran to wash the powder, dry it under vacuum at 50 °C until the weight is constant, with a yield of 73.7%.

[0089] The crystal powder was subjected to X-ray powder diffraction analysis, with the same instrument parameters as in Example 1. Figure 3 As shown in Table 2, the obtained crystal form has characteristic peaks at 2θ = 5.49°, 8.663°, 10.966°, 16.46°, 19.031°, 19.562°, 22.010°, and 24.921°, which is the same as crystal form B in Example 1. (DSC spectrum) Figure 4 The results show an endothermic peak at 260℃.

[0090] Table 2

[0091]

[0092]

[0093] Example 3

[0094] Prepare 50 mL of 133 g / L acetyl hexapeptide-8 aqueous solution, stir continuously at 32 °C and 150 rpm, add 2 times the volume of isopropanol at a rate of 40 mL / h, and after the addition is completed, cool down to 12 °C at a rate of 8 °C per hour to crystallize for 6 h. After filtering and washing the powder with an appropriate amount of isopropanol, dry under vacuum at 50 °C until the weight is constant, with a yield of 74.8%.

[0095] The crystal powder was sent for X-ray powder diffraction testing, and the instrument parameters were the same as in Example 1.

[0096] like Figure 5As shown in Table 3, the obtained crystal form has characteristic peaks at 2θ = 4.478°, 6.458°, 17.740°, 19.233°, 20.227°, 23.034°, and 26.947°, and is named crystal form C. (DSC spectrum) Figure 6 The results show an endothermic peak at 255.1℃.

[0097] Table 3

[0098]

[0099]

[0100] Example 4

[0101] Prepare 50 mL of 133 g / L acetyl hexapeptide-8 aqueous solution, stir continuously at 32 °C and 150 rpm, add 3 times the volume of DMF at a rate of 60 mL / h, and after the addition is completed, cool down to 12 °C at a rate of 8 °C per hour for 6 h to crystallize. After filtering an appropriate amount of DMF to wash the powder, dry under vacuum at 50 °C until the weight is constant, with a yield of 78.5%.

[0102] The crystal powder was subjected to X-ray powder diffraction analysis, with the same instrument parameters as in Example 1. Figure 7 As shown in Table 4, the obtained crystal form has characteristic peaks at 2θ = 6.887°, 13.764°, 19.284°, 20.141°, 20.603°, and 23.233°, and is named crystal form D. (DSC spectrum) Figure 8 The results show two endothermic peaks at 248.8℃ and 255.5℃.

[0103] Table 4

[0104]

[0105]

[0106] Example 5

[0107] Prepare 50 mL of 133 g / L acetyl hexapeptide-8 aqueous solution, stir continuously at 32 °C and 150 rpm, and add 2 times the volume of 1,4-dioxane at a rate of 40 mL / h. After the addition is completed, cool down to 12 °C at a rate of 8 °C per hour to crystallize for 6 h. After filtering out an appropriate amount of 1,4-dioxane to wash the powder, dry under vacuum at 50 °C until the weight is constant, with a yield of 82.1%.

[0108] The crystal powder was subjected to X-ray powder diffraction analysis, with the same instrument parameters as in Example 1. Figure 9As shown in Table 5, the obtained crystal form has characteristic peaks at 2θ = 5.02°, 6.545°, 12.092°, 15.43°, 17.717°, 18.758°, 19.556°, 21.380°, and 23.953°, and is named crystal form E. (DSC spectrum) Figure 10 The results showed two endothermic peaks at 250.5°C and 255.7°C, which are similar to those in Example 2.

[0109] Table 5

[0110]

[0111] Example 6

[0112] Preparation of oil-soluble acetyl hexapeptide-8

[0113] Each of the following groups of acetyl hexapeptide-8 lyophilized powder and acetyl hexapeptide-8 crystalline powder prepared in Examples 1-5 was weighed and dissolved in 10 mL of pure water. Then, 20 g of polyglycerol-2 isostearate was weighed and added to 65 g of isohexadecane. After mixing, 5 g of 1,2-hexanediol was slowly added. This process was repeated for 6 groups. Then, 5 g of aqueous solutions of different acetyl hexapeptide-8 powders were slowly added to each group to obtain 6 groups of oil-soluble acetyl hexapeptide-8.

[0114] The above six groups of oil-soluble acetyl hexapeptide-8 were dispensed into 10 mL portions and placed in a 45℃ drying oven. The changes in the content of the active ingredient were observed using high-performance liquid chromatography (HPLC). Figure 11 As shown, the content of acetyl hexapeptide-8 prepared from lyophilized acetyl hexapeptide-8 rapidly decreased to only 6% after 12 weeks, while the content of acetyl hexapeptide-8 prepared from crystal form B was 56%~59%, and the content of acetyl hexapeptide-8 prepared from crystal forms C, D, and F was the most stable at 80%~85%.

[0115] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A crystalline form C of acetyl hexapeptide-8, characterized by, The X-ray powder diffraction pattern has diffraction peaks at 2θ±0.2° positions, including: 4.478°, 6.458°, 17.740°, 19.233°, 20.227°, 23.034° and 26.947°.

2. The crystalline Form C of acetyl hexapeptide-8 according to claim 1, characterized by, The X-ray powder diffraction pattern is shown in Figure 5; The crystal form C has an endothermic peak at 255.1±2℃.

3. A method for preparing the crystal form C of acetyl hexapeptide-8 according to any one of claims 1-2, comprising the following steps: contacting an aqueous solution of acetyl hexapeptide-8 with a poor solvent to crystallize to obtain the crystal form C of acetyl hexapeptide-8; the poor solvent is isopropanol.

4. A crystalline Form D of acetyl hexapeptide-8, characterized by, The X-ray powder diffraction pattern has diffraction peaks at 2θ±0.2° positions, including: 6.887°, 13.764°, 19.284°, 20.141°, 20.603° and 23.233°.

5. The crystal form D of acetyl hexapeptide-8 according to claim 4, characterized in that, The X-ray powder diffraction pattern is shown in Figure 7; The crystal form D has endothermic peaks at 248.8±2℃ and 255.5±2℃.

6. A method for preparing the crystal form D of acetyl hexapeptide-8 according to any one of claims 4-5, comprising the following steps: contacting an aqueous solution of acetyl hexapeptide-8 with a poor solvent to crystallize to obtain the crystal form D of acetyl hexapeptide-8; the poor solvent is DMF.

7. A crystalline Form E of acetyl hexapeptide-8 characterized by, The X-ray powder diffraction pattern has diffraction peaks at 2θ±0.2° positions, including: 5.02°, 6.545°, 12.092°, 15.43°, 17.717°, 18.758°, 19.556°, 21.380° and 23.953°.

8. The crystalline Form E of acetyl hexapeptide-8 of claim 7, characterized in that, The X-ray powder diffraction pattern is shown in Figure 9; The crystal form E has endothermic peaks at 250.5±2℃ and 255.7±2℃.

9. A method for preparing the crystal form E of acetyl hexapeptide-8 according to any one of claims 7-8, comprising the following steps: contacting an aqueous solution of acetyl hexapeptide-8 with a poor solvent to crystallize to obtain the crystal form E of acetyl hexapeptide-8; the poor solvent is 1,4-dioxane.

10. Use of the crystal form C of acetyl hexapeptide-8 according to any one of claims 1-2, the crystal form D of acetyl hexapeptide-8 according to any one of claims 4-5 and / or the crystal form E of acetyl hexapeptide-8 according to any one of claims 7-8 in the preparation of an oil-soluble cosmetic.

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