Preparation method of a metal-chitosan catalyst, the prepared catalyst and its application

Abstract

The present invention provides a method for preparing a metal-chitosan catalyst, comprising the following steps: I. Dissolve chitosan in water under acidic conditions; II. Add a metal compound and stir; the metal compound is selected from one or more of zinc oxide, zinc sulfate, zinc chloride, magnesium chloride and iron chloride; III. Dropwise add an aqueous solution of sodium tripolyphosphate, and after dropping, continue to stir until the reaction ends; IV. Lyophilize the reaction system to obtain the metal-chitosan catalyst. The present invention also provides the application of the metal-chitosan catalyst in the preparation of salicylic acid-grafted chitosan and the prepared salicylic acid-grafted chitosan. In particular, the present invention also provides a salicylic acid-grafted chitosan for cosmetics, a skin external composition containing the salicylic acid-grafted chitosan and its uses.

Description

Technical Field

[0001] The invention belongs to the field of polymers and cosmetics, and specifically relates to a novel preparation method of a metal-chitosan catalyst for catalyzing salicylic acid grafting chitosan, the catalyst prepared by the method and the application of the catalyst in a skin external composition. Background Art

[0002] Salicylic acid has whitening and acne-removing effects, but it is somewhat irritating to the skin. Salicylic acid grafted chitosan can reduce the irritation of salicylic acid and improve the absorption and release efficiency of salicylic acid. The reaction formula of salicylic acid grafted chitosan is as follows:

[0003]

[0004] In order to increase the grafting rate, palladium (Pd), gold (Au) and other precious metals are generally used as catalysts. For example, the Chinese invention patent application "A chitosan grafted salicylic acid microcapsule and its preparation method" with publication number CN113101375A (publication date July 13, 2021) discloses salicylic acid as the core material, chitosan is grafted on salicylic acid through weak bond bonding, a special compound emulsifier is screened, and precious metals (gold, palladium, molybdenum or copper) are used as catalysts. The core material is used to prepare stable charged droplets as a template, and the precious metal catalyst is used to catalyze the grafting polymerization reaction between the salicylic acid emulsion and chitosan to form nano-charged particles; on this basis, the salicylic acid particles are reinforced with oppositely charged wall materials, and finally the curing agent calcium chloride is used to encapsulate to form stable nanoparticles. This method is relatively cumbersome to operate, and the precious metal catalyst is brought into the grafted product, which is likely to affect its safety.

[0005] In addition, chitosan grafted with salicylic acid is mostly used in the fields of daily chemicals and medicine. For the safety of users, water is often used as a solvent in the reaction. However, the above-mentioned amidation reaction is a dehydration condensation, and the reaction in a water-containing system will greatly reduce the grafting rate. In order to improve the grafting rate, a solution using ethanol, benzene, etc. as a solvent in the reaction system has appeared in the prior art. Specifically, organic solvents such as ethanol and benzene form a ternary azeotropic system with water generated by the grafting reaction, and then remove water by azeotropic entrainment, thereby improving the grafting rate. For example, the Chinese invention patent application "2-chitosan·salicylic acid grafted compound and its preparation method" with publication number CN1775815A (publication date May 24, 2006) discloses that ethanol or ethanol-benzene mixture is used as a dispersant or azeotropic entrainer, and the average grafting rate can reach 70% to 75%. However, organic solvents such as benzene cannot be used in skin external compositions such as cosmetics, and multiple purifications are required to remove the residual organic solvents.

[0006] Therefore, it is necessary to develop a safe and convenient method for preparing salicylic acid grafted chitosan suitable for skin external use compositions (such as cosmetics). Summary of the invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides a method for preparing a metal-chitosan catalyst for grafting salicylic acid, and a metal-chitosan catalyst prepared by the method. Chitosan is not only a carrier of the catalyst, but also a reaction substrate for the chitosan grafting reaction of salicylic acid. The catalyst provided by the present invention can increase the grafting rate of salicylic acid, and the composition after the reaction is completed can be directly used as a raw material of a skin external composition without being treated.

[0008] Therefore, an object of the present invention is to provide a method for preparing a metal-chitosan catalyst, comprising the steps of:

[0009] I. dissolving chitosan in water under acidic conditions;

[0010] II. Add a metal compound and stir; the metal compound is selected from one or more of zinc oxide, zinc sulfate, zinc chloride, magnesium chloride and ferric chloride;

[0011] III. Add sodium tripolyphosphate aqueous solution dropwise, and continue stirring until the reaction is complete;

[0012] IV. freeze-drying the reaction system to obtain the metal-chitosan catalyst.

[0013] Preferably, the weight proportions of the chitosan, the metal compound and the sodium tripolyphosphate are respectively:

[0014] 0.5-5 parts by weight of chitosan, 0.1-2 parts by weight of metal compound, 0.1-2 parts by weight of sodium tripolyphosphate;

[0015] And independently of each other, the weight of the chitosan is not less than 2 times the weight of the metal compound or the sodium tripolyphosphate.

[0016] Preferably, the chitosan is refined chitosan with a deacetylation degree of more than 95%.

[0017] Preferably, the refined chitosan with a deacetylation degree of more than 95% is prepared by the following method:

[0018] The chitosan with a deacetylation degree of more than 95% is added to a 1%-10% (w / w) acetic acid aqueous solution, stirred and dissolved to make the chitosan content of 1%-10%, filtered, 1%-20% (w / w), preferably 5% (w / w) sodium hydroxide solution is added dropwise to the filtrate, the pH value of the system is adjusted to 8-10, preferably pH 9, and allowed to stand for more than 0.5 hour, preferably 2 hours, filtered, the filter cake is washed with 70-95% (w / w) ethanol, and then vacuum dried to obtain the product.

[0019] Preferably, the vacuum drying parameters are vacuum degree 0.08MPa-0.09MPa and temperature 50°C-65°C.

[0020] Preferably, in the step I, the acidic condition refers to pH=5-6.

[0021] Also preferably, in the step I, an acid is added to adjust the pH to 5-6, and the acid is selected from one or more of hydrochloric acid, acetic acid, lactic acid, oxalic acid and glycolic acid.

[0022] Preferably, in step I, the chitosan is dissolved in 15-30 times the weight of water.

[0023] More preferably, in step I, the chitosan is dissolved in 20-25 times the weight of water.

[0024] Preferably, in step II, the metal compound is one or more of zinc oxide, zinc sulfate, zinc chloride and magnesium chloride.

[0025] Preferably, in step II, after adding the metal compound, stirring is carried out for at least half an hour.

[0026] Preferably, the weight percentage concentration of the sodium tripolyphosphate aqueous solution is 5%-20%, more preferably 8%-15%.

[0027] Also preferably, in step III, after the sodium tripolyphosphate aqueous solution is added dropwise, stirring is continued for more than 0.5 hour.

[0028] In step IV, freeze drying is performed according to conventional processes and steps in the art.

[0029] Another object of the present invention is to provide a metal-chitosan catalyst for salicylic acid grafting, wherein the metal-chitosan catalyst is prepared by the above preparation method.

[0030] In addition, the present invention also provides the use of the metal-chitosan catalyst in the preparation of salicylic acid grafted chitosan, comprising adding the metal-chitosan catalyst in batches into a non-aqueous solvent solution of salicylic acid and reacting at 60°C-80°C until complete.

[0031] Therefore, the present invention also provides a method for preparing salicylic acid grafted chitosan, comprising the following operations:

[0032] Salicylic acid and a non-aqueous solvent are mixed and heated to 60°C-80°C to dissolve the salicylic acid; the metal-chitosan catalyst is added in batches, stirred, and kept warm until the reaction is completed;

[0033] Wherein, the weight ratio of chitosan and salicylic acid in the metal-chitosan catalyst is 1:1-1:2.

[0034] Also preferably, the reaction temperature is 70°C-80°C.

[0035] Also preferably, the reaction time is 1-6 hours; more preferably 1-3 hours.

[0036] The invention also provides salicylic acid grafted chitosan prepared by the method.

[0037] As a preferred embodiment, the present invention provides a method for preparing a cosmetic product grafted with chitosan using salicylic acid, comprising the following steps:

[0038] Salicylic acid and monohydric or polyhydric lower fatty alcohol are mixed and heated to 60°C-80°C to dissolve the salicylic acid; the metal-chitosan catalyst prepared according to the method of the present invention is added in batches, stirred, and kept warm until the reaction is completed; the weight ratio of chitosan to salicylic acid in the metal-chitosan catalyst is: 1:1-1:2;

[0039] Wherein, when preparing the metal-chitosan catalyst, the metal compound is one or more of nano zinc oxide, nano zinc sulfate, nano zinc chloride and nano magnesium chloride; the monovalent or polyvalent lower fatty alcohol is selected from one or more of glycerol, propylene glycol, butylene glycol, pentanediol, ethanol, caprylyl glycol, isopropanol, hexylene glycol, methyl propanediol, ethoxydiglycol and dipropylene glycol.

[0040] Preferably, the weight ratio of the salicylic acid to the monohydric or polyhydric lower fatty alcohol is 1:5-1:20; more preferably 1:8-1:12.

[0041] Also preferably, the reaction temperature is 70°C-80°C.

[0042] Also preferably, the reaction time is 1-6 hours; more preferably 1-3 hours.

[0043] Therefore, the present invention provides a cosmetic prepared by the above method using chitosan grafted with salicylic acid.

[0044] In addition, another object of the present invention is to provide a composition for external use on skin, with a pH of 3-4, comprising the above-mentioned cosmetic grafted with chitosan using salicylic acid, and also comprising a vitamin C derivative, vitamin E and water; based on the total weight of the composition for external use on skin, the weight percentages of the components are:

[0045] The cosmetic comprises 0.5%-2% chitosan grafted with salicylic acid, 0.5%-5% vitamin C or its derivatives, 0.5%-5% vitamin E, and the balance is water.

[0046] Preferably, the vitamin C derivative is selected from one or more of magnesium ascorbyl phosphate, ascorbyl tetraisopalmitate, 3-o-ethyl ascorbic acid and ascorbyl glucoside in any ratio.

[0047] The preparation method of the skin external composition comprises: mixing the components uniformly at 40° C.-50° C., and adjusting the pH to 3-4 with a pH regulator to obtain the composition.

[0048] Preferably, the pH regulator is selected from one or more of sodium hydroxide, potassium hydroxide, betaine, sodium bicarbonate and triethanolamine in any proportion.

[0049] In addition, the present invention also provides the use of the above-mentioned external skin composition in preparing a composition for treating skin acne.

[0050] The above composition for external use on skin can be applied to the acne area on the face to form a thin film that adheres closely to the skin, thereby exerting its efficacy.

[0051] In this specification, unless otherwise specified, the "water" refers to purified deionized water, distilled water, double distilled water and / or water for injection, etc.

[0052] In this specification, the "parts by weight" of the components represent the relative dosage ratio of the components, rather than the actual mass number. According to actual conditions, 1 part by weight can be 1g, 5g, 10g, 1kg, 1.5kg, 10kg, etc.

[0053] The preparation method of the metal-chitosan catalyst and the preparation method of the salicylic acid grafted chitosan for cosmetics provided by the present invention use safe and environmentally friendly raw materials.

[0054] The metal-chitosan catalyst of the present invention is used to prepare cosmetics grafted with chitosan with salicylic acid, and the chitosan is directly used to prepare the skin external composition without any treatment. Therefore, the ingenious concept of the present invention is:

[0055] (1) The metal-chitosan catalyst, wherein the chitosan serves as both a carrier of the metal catalyst and a raw material for the salicylic acid grafting reaction.

[0056] (2) When the catalyst is used to prepare cosmetics grafted with salicylic acid chitosan, the metal ions (Zn 2+ Mg 2+ ) After efficiently catalyzing the amidation grafting reaction of salicylic acid and chitosan, it can be used as a component in the skin external composition to synergize with vitamin C derivatives: protecting the activity of vitamin C derivatives, improving skin pigmentation caused by skin inflammation and acne together with vitamin C derivatives, and accelerating the synthesis of skin collagen.

[0057] (3) When preparing cosmetics grafted with chitosan using salicylic acid, the monovalent or polyvalent lower fatty alcohol used not only acts as a solvent for salicylic acid, which is beneficial to the grafting reaction, but also plays a synergistic role with chitosan in the skin external composition: when the skin external composition is applied on the skin, a chitosan semipermeable membrane is formed, and the percutaneous absorption of salicylic acid is promoted with the help of the osmotic pressure of the semipermeable membrane. At the same time, the chitosan semipermeable membrane locks in moisture, increases the water content of the stratum corneum of the skin, helps the stratum corneum lock in moisture, slows down the loss of moisture, and thus maintains the barrier effect of the skin for a longer period of time.

[0058] In the skin external composition of the present invention, the vitamin C derivative and vitamin E act synergistically to remove free radicals, improve pigmentation caused by acne, and brighten skin color.

[0059] According to skin efficacy measurement, the skin external use composition of the present invention has a significant acne removal effect and is non-irritating to the skin. DETAILED DESCRIPTION

[0060] The present invention is described below with reference to specific examples. It will be appreciated by those skilled in the art that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0061] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents and materials used in the following examples are commercially available products unless otherwise specified. The purchase of some reagents and raw materials is as follows:

[0062] Chitosan with a deacetylation degree of more than 95%: Shandong Luhai Lansheng Biotechnology Co., Ltd.;

[0063] Salicylic acid: Spike (Guangzhou) Biotechnology Co., Ltd.;

[0064] Sodium tripolyphosphate: Wujiang Huaxu Chemical Technology Co., Ltd.;

[0065] Nano zinc chloride: Shandong Guoci Functional Materials Co., Ltd.

[0066] Nano zinc oxide: Shandong Guoci Functional Materials Co., Ltd.

[0067] Nano magnesium chloride: Beijing Kangpu Huiwei Technology Co., Ltd.;

[0068] Nano zinc sulfate: Beijing Kangpu Huiwei Technology Co., Ltd.;

[0069] Ascorbyl glucoside: Anhui Tianyin Biotechnology Co., Ltd.;

[0070] Magnesium ascorbyl phosphate: Anhui Tianyin Biotechnology Co., Ltd.;

[0071] 3-o-ethyl ascorbic acid: SPIEC (Guangzhou) Biotechnology Co., Ltd.;

[0072] Vitamin E: Zhejiang Xinhecheng Co., Ltd.;

[0073] Glycerin: Qingdao Shengyue International Trade Co., Ltd.;

[0074] Butanediol: Shandong Haike Xinyuan Materials Technology Co., Ltd.;

[0075] Pentanediol: Shandong Haike Xinyuan Materials Technology Co., Ltd.;

[0076] Methylpropanediol: Guangzhou Rong Daxing Chemical Co., Ltd.;

[0077] Caprylyl glycol: Guangzhou Rong Daxing Chemical Co., Ltd.;

[0078] Ethoxydiglycol: Guangzhou Rong Daxing Chemical Co., Ltd.;

[0079] Propylene glycol: Shandong Haike Xinyuan Materials Technology Co., Ltd.;

[0080] Dipropylene glycol: Nanjing Chenlong Chemical Co., Ltd.;

[0081] Hexanediol: Shandong Haike Xinyuan Materials Technology Co., Ltd.

[0082] The purchased chitosan with a deacetylation degree of more than 95% is refined by the following method:

[0083] The chitosan is added into a 1%-10% (w / w) acetic acid aqueous solution, stirred and dissolved to make the chitosan content be 1%-10%, filtered, a 5% (w / w) sodium hydroxide solution is added dropwise into the filtrate, the pH value of the system is adjusted to 9, the mixture is allowed to stand for more than 0.5 hour, filtered, the filter cake is washed with 70%-95% (w / w) ethanol, and then dried at a relative vacuum degree of -0.6MPa to -0.9MPa and 50-65°C to obtain the product.

[0084] Examples 1 to 8 A metal-chitosan catalyst for salicylic acid grafting

[0085] The raw materials of the metal-chitosan catalyst for salicylic acid grafting of Examples 1 to 8 are shown in Table 1 and are prepared by the following process:

[0086] Add refined deacetylated chitosan to a three-necked flask, add 15-30 times, preferably 20-25 times the weight of deionized water, stir evenly, then add acid, adjust pH to 5-6, after the deacetylated chitosan is dissolved, add the metal compound, and continue stirring for half an hour. Dissolve sodium tripolyphosphate in 5-15 times, preferably 10 times the weight of deionized water to obtain a sodium tripolyphosphate aqueous solution; then slowly add it dropwise to the reaction system. After the dropwise addition, continue stirring for half an hour, pour out, and freeze-dry according to conventional operations to obtain a loose and porous metal-chitosan catalyst.

[0087] Table 1 Raw materials and output of metal-chitosan catalysts described in Examples 1-8

[0088]

[0089] Example 9-16 A cosmetic using chitosan grafted with salicylic acid

[0090] The raw materials of chitosan grafted with salicylic acid are used in the cosmetics described in Examples 9-16, as shown in Table 2, and are prepared by the following process:

[0091] Salicylic acid and polyol were added to a three-necked flask with a stirring device, and stirred. The mixture was heated in a water bath to 60°C-80°C, preferably 70°C-80°C, to dissolve the salicylic acid. The metal-chitosan catalysts prepared in Examples 1-8 were then added in batches, stirred at a stirring speed of 200 r / min, and kept warm for 3 hours. After the reaction was completed, the mixture was cooled to 40°C-50°C and directly used in the subsequent examples to prepare a skin external composition.

[0092] Table 2: Salicylic acid grafted chitosan raw materials for cosmetics of Examples 9-18

[0093]

[0094] Examples 17 to 24: Composition for external use on skin

[0095] The skin external application compositions of Examples 17 to 24, the raw material compositions are shown in Table 3, and are prepared by the following process:

[0096] At 40°C-50°C, add vitamin C derivative and vitamin E to the three-necked flask containing salicylic acid-grafted chitosan of Examples 9-16 respectively, add deionized water to a total weight of 100 g, and stir evenly; increase the stirring speed to 500 r / min, add a pH adjuster to the reaction bottle, and adjust the pH value of the system to 3-4.

[0097] Table 3 Raw materials of the skin external application composition of Examples 17 to 24

[0098]

[0099] Test Example 1 Anti-acne effect of the skin external composition of the present invention (I)

[0100] 1. Test samples:

[0101] According to the raw material ratios and methods described in Examples 17 to 21 and 23 to 24, the skin external composition was prepared and packaged, 10 mL / tube. Five tubes of the skin external composition of each example were randomly selected, mixed and shuffled, and randomly assigned and numbered during testing.

[0102] How to use the test sample:

[0103] Use for 7 days, twice a day. After cleansing in the morning and evening, take an appropriate amount of sample and apply it evenly on the acne-prone skin on the face. During the entire test period, in addition to the test sample provided, no other skin care products with the same efficacy (except cleansing facial cleansers) can be used in the test area (acne area).

[0104] 2. Test cycle:

[0105] 2022.05.13-2022.06.03

[0106] 3. Requirements for volunteers :

[0107] 3.1 Signing the Informed Consent Form

[0108] All 31 volunteers signed informed consent forms before the test. Before the volunteers signed the informed consent forms, the testers informed the volunteers of the purpose of the test, possible benefits, potential risks and problems, and related rights and obligations.

[0109] 3.2 Inclusion criteria

[0110] (1) Healthy men or women, aged 18-50 years;

[0111] (2) Oily skin or oily and acne-prone skin;

[0112] (3) Acne prone to occur on the face (combined acne, inflammatory acne, retention acne), severity level ≤ 2 (Pillsbury's 4-level grading system);

[0113] (4) At least one pimple is developing;

[0114] (5) Be able to cooperate well with the experimenters and maintain a regular life during the study;

[0115] (6) Be able to read and understand all the contents of the informed consent form, and voluntarily sign the informed consent form and fill out the project questionnaire;

[0116] (7) Agree not to use any cosmetics, drugs or health products that may affect the results during the trial;

[0117] (8) No allergic diseases, no history of allergy to cosmetics or other external preparations;

[0118] (9) The skin of the test area should be free of birthmarks, inflammation, scars, excessive hair growth, etc.;

[0119] (10) Other corresponding inclusion criteria.

[0120] 3.3 Exclusion criteria

[0121] (1) Those with facial skin diseases that may affect the judgment of the test results;

[0122] (2) Those with highly allergic constitution;

[0123] (3) Women who are pregnant, breastfeeding, or planning to become pregnant during the testing period;

[0124] (4) Those with severe heart, liver, or kidney damage and severe immunodeficiency;

[0125] (5) Those with mental illness, severe endocrine disease, or those taking contraceptive pills;

[0126] (6) Those who have participated in drug clinical trials or other trials within 30 days, or those who have systematically used drugs that may affect the trial results within the past week;

[0127] (7) Those who have taken oral or topical corticosteroids or other anti-inflammatory drugs in the past month;

[0128] (8) Those who have used retinoic acid preparations or undergone chemical peeling, laser, pulsed light or other medical aesthetic treatments on the test area within the past month;

[0129] (9) Those who cannot avoid prolonged exposure to sunlight;

[0130] (10) Those who cannot complete the specified content according to the test requirements;

[0131] (11) Those who are considered by the researchers to be unsuitable for participation in this study;

[0132] (12) Other corresponding exclusion criteria.

[0133] 3.4 Restrictions

[0134] (1) Subjects should avoid taking or applying any drugs or related products other than the test products, such as antibiotics, anti-inflammatory drugs, etc., two weeks before and during the test period;

[0135] (2) Do not wear any makeup on the day of the test;

[0136] (3) Before the test at each time point, the subjects cleansed their faces and then rested in a constant temperature and humidity room to ensure that the skin remained stable for 30 minutes before the test;

[0137] (4) During the test, it is prohibited to use other skin care products or products that may affect the test on the test area; and reduce outdoor strong sun exposure activities, and prohibit activities such as travel and vacation that are exposed to excessive ultraviolet rays;

[0138] (5) During the test period, you are not allowed to eat any irritating food (such as alcohol, chili peppers, etc.).

[0139] 3.5 Subjects

[0140] A total of 33 people were enrolled, 31 of whom completed the test and had valid test data for 31 people.

[0141] 4. Test Methods :

[0142] 4.1 Test Basis

[0143] "PLTC-GX-SOP-013 Acne Treatment Efficacy Evaluation Test Operation Instructions"

[0144] 4.2 Testing Process

[0145] D0 (first day of subject visit)

[0146] 1) Volunteer screening

[0147] The doctor assessed the facial acne condition of the subjects, and the severity level was ≤ level 2 (Pillsbury's 4-level grading method), and those who met the inclusion and exclusion requirements were enrolled in the group;

[0148] 2) Volunteers sign the subject information registration and sign the informed consent form;

[0149] 3) Clean the test area. The subjects use alkaline soap products to clean the entire face uniformly and wipe it clean with dry facial tissue;

[0150] 4) Exposure of the test part and waiting: the subject exposed the test part (face) and sat quietly in a laboratory with a temperature of 21±1C50±10%R1 for 30 minutes;

[0151] 5) Test the subject's skin base value, the doctor scores and counts the acne levels, and the laboratory technician uses Primos to take photos of the subject's facial acne;

[0152] 6) Laboratory technicians instruct subjects on how to use the test samples according to the use requirements and site of use of the test samples, and provide written test precautions and product instructions;

[0153] 7) The laboratory technician numbers and weighs the test samples and records them. The subject collects the samples and leaves the laboratory.

[0154] D3 (The subject uses the test sample for 3 days)

[0155] 1) The subject is followed up. The laboratory technician asks the subject about the usage of the sample and any adverse reactions, weighs and records the sample, and reminds the user to strictly follow the usage method.

[0156] 2) Clean the test area. The subject uses an alkaline soap-based product to uniformly clean the entire face and wipes it dry with a dry paper towel.

[0157] 3) Expose the test area and wait. The subject exposes the test area (face) and sits quietly in the laboratory at a temperature of 21 ± 1°C and 50 ± 10% relative humidity for 30 minutes while completing a questionnaire.

[0158] 4) Test the skin data values of the subject. The doctor grades and counts the acne and comedone levels; the laboratory technician uses Primos to photograph the acne on the subject's face.

[0159] D7 (The subject uses the test sample for 7 days)

[0160] 1) The subject is followed up. The subject returns the sample, and the laboratory technician weighs and records it.

[0161] 2) Clean the test area. The subject uses an alkaline soap-based product to uniformly clean the entire face and wipes it dry with a dry paper towel.

[0162] 3) Expose the test area and wait. The subject exposes the test area (face) and sits quietly in the laboratory at a temperature of 21 ± 1°C and 50 ± 10% relative humidity for 30 minutes while completing a questionnaire.

[0163] 4) Test the skin data values of the subject; the doctor grades and counts the acne and comedone levels; the laboratory technician uses Primos to photograph the acne on the subject's face.

[0164] 4.3 Test items and instruments used: See Table 4.

[0165] Table 4 Test items and instruments

[0166]

[0167] 4.4 Subject self-evaluation

[0168] The self-evaluation questionnaire is shown in Table 5.

[0169] Table 5 Self-evaluation questionnaire

[0170]

[0171]

[0172] The cumulative percentage of “very satisfied” and “satisfied” is taken as the satisfaction rate.

[0173] 5. Test result statistical method

[0174] SPSS software was used to perform relevant statistical analysis on the result data.

[0175] Quantitative data were tested for normal distribution. Paired t test was used for paired data that met normal distribution, and Wilcoxon paired test was used for paired data that did not meet normal distribution and ranked data.

[0176] For qualitative data (self-assessment questionnaire), the cumulative percentage of all beneficial items was taken as the satisfaction rate, and the results were subjected to a binomial test.

[0177] The significant difference level was P<0.05.

[0178] 6. Results :

[0179] 6.1 Completion status of subjects

[0180] (1) Completion status: 33 subjects were enrolled, and two subjects withdrew due to personal reasons and did not return for follow-up on time, so the actual number of completed subjects was 31.

[0181] (2) Age: See Table 6.

[0182] Table 6 Age of subjects

[0183] Sample size Minimum Maximum average value Standard Deviation 31 20 50 33.2 7.0

[0184] 6.2 Adverse reactions during use

[0185] All 31 subjects used the product as required at the prescribed time and no adverse reactions occurred.

[0186] 6.3 Acne volume test results: see Table 7.

[0187] Table 7 Acne volume test results

[0188]

[0189] a :Acne volume reduction rate (%) = [(D0 test value - test value after using the product for N days) / D0 test value] × 100%;

[0190] b : Compare with D0 test value.

[0191] Conclusion: After using all the tested samples for 3 and 7 days, the acne volume was significantly reduced, with the reduction rates being 35.90% and 64.59%, respectively, showing a certain time (cumulative dose) dependence.

[0192] 6.4 Physician evaluation of skin lesion count test results: see Table 8.

[0193] Table 8 Physician evaluation of skin lesion count test results

[0194]

[0195] a Skin lesion regression rate (%) = (D0 test value - test value after using the product for N days) / D0 test value] × 100%;

[0196] b : Compare with D0 test value.

[0197] Conclusion: After 3 and 7 days of use, the lesion counts of all tested samples were significantly reduced, and the lesion regression rates were 26.41% and 63.64%, respectively, showing a certain time (cumulative dose) dependence.

[0198] 6.5 Doctors evaluate ISGA score test results: see Table 9.

[0199] Table 9 Doctors' evaluation of ISGA score test results

[0200]

[0201] a : Skin lesion reduction percentage (%) = [(D0 score - score of product use for N days) / D0 score × 100%;

[0202] b : Compared with D0 score value.

[0203] Conclusion: After using the product for 7 days, the ISGA scores of all test samples were significantly reduced, and the skin lesion reduction rate was 25.58%.

[0204] 6.6 Subject self-assessment

[0205] The statistical results of the subject questionnaire are shown in Table 10, and the analysis of the self-assessment results is shown in Table 11.

[0206] Table 10 Statistical results of the questionnaires of the subjects

[0207]

[0208] Table 11 Analysis of self-evaluation results

[0209]

[0210] 7. Test Conclusion :

[0211] This test result was obtained by selecting 31 subjects with acne that met the requirements through expert evaluation, using the test samples for 7 consecutive days and through instrument detection, expert evaluation and subject self-evaluation. The test results showed that all test samples had the following effects: effectively reducing the volume of facial acne and significantly improving skin lesions.

[0212] Test Example 2 Anti-acne effect of the skin external composition of the present invention (II)

[0213] 1. Test samples

[0214] 1.1 Test sample information

[0215] 1.1.1A Sample: a composition for external use on skin prepared according to the raw material ratio and method described in Example 17, viscous liquid, packaged, 10 ml / tube;

[0216] 1.1.2B Sample: Commercially available anti-acne gel product, gel-like liquid, containing 2% salicylic acid and 20% azelaic acid, 15ml / tube.

[0217] Both samples A and B were repackaged and had no difference in appearance.

[0218] 1.2 How to use the test sample

[0219] Same as the “Test Sample Usage Method” under “1. Test Sample” in Test Example 1.

[0220] 2. Test Purpose

[0221] Evaluate and compare the acne removal effects of samples A and B.

[0222] 3. Test cycle:

[0223] 2022.12.19-2023.01.10.

[0224] 4. Subjects

[0225] 4.1 Signing of Informed Consent

[0226] 40 volunteers were randomly divided into two groups, A and B, with 20 people in each group. All of them signed informed consent forms before the test. Group A subjects used sample A, and Group B subjects used sample B. Before the subjects signed the informed consent forms, the testers informed the volunteers of the purpose, possible benefits, potential risks and problems of the test, as well as the relevant rights and obligations.

[0227] 4.2 Inclusion Criteria

[0228] Same as “3.2 Inclusion Criteria” under “3. Requirements for Test Volunteers” in Test Example 1.

[0229] 4.3 Exclusion criteria

[0230] Same as “3.3 Exclusion criteria” under “3. Requirements for test volunteers” in Test Example 1.

[0231] 4.4 Restrictions

[0232] Same as “3.4 Restrictions” under “3. Requirements for Test Volunteers” in Test Example 1.

[0233] 4.5 Number of subjects

[0234] A total of 40 people were enrolled, 34 of whom completed the test and had valid test data.

[0235] 5. Test Methods

[0236] 5.1 Test Basis

[0237] 《TTDCA 004-2021 Test Method for Anti-Acne Effect of Cosmetics》

[0238] 5.2 Testing Process

[0239] Tests were conducted on D0 (the first day of the subject’s visit) and D7 (the subject used the test sample for 7 days). The test methods and steps were the same as those for D0 and D7 in “4.2 Test Procedure” under “4. Test Method” of Test Example 1.

[0240] 5.3 Test items and instruments:

[0241] Same as “4.3 Test Items and Instruments” under “4. Test Method” in Test Example 1.

[0242] 6. Test result statistical method

[0243] SPSS software was used to conduct relevant statistical analysis on the result data. The measurement data were analyzed by histogram and PP diagram to test the normal distribution of measurement data. Cronbach reliability analysis was used to verify the reliability of the data through the coefficient to confirm whether it can be used for research analysis. Pearson correlation method was further used to study the influence and correlation of gender and age on the questions, confirming that sampling had no significant effect on the results.

[0244] 7. Test Results

[0245] 7.1 Completion status of subjects

[0246] Under the conditions of this experiment, a total of 40 subjects were included, 34 of whom completed the test, with 17 subjects in Group A and 17 subjects in Group B.

[0247] 7.2 Adverse reactions during use

[0248] All 34 subjects used the product as required at the prescribed time and no adverse reactions occurred.

[0249] 7.3 Acne volume test results

[0250] 7.3.1 Acne volume test results of subjects in Group A: see Table 12.

[0251] Table 12 Acne volume test results of subjects in group A

[0252]

[0253] a :Acne volume reduction rate (%) = [(D0 test value - D7 test value) / D0 test value] × 100%; b : Compare with D0 test value.

[0254] 7.3.2 Acne volume test results of subjects in group B: see Table 13.

[0255] Table 13 Acne volume test results of group B subjects

[0256]

[0257] a :Acne volume reduction rate (%) = [(D0 test value - D7 test value) / D0 test value] × 100%; b : Compare with D0 test value.

[0258] 7.4 Physician Evaluation of Lesion Count Test Results

[0259] 7.4.1 Results of the doctor’s skin lesion count test for subjects in Group A: see Table 14.

[0260] Table 14 Results of skin lesion count test evaluated by doctors in group A

[0261]

[0262] a : Skin lesion regression rate (%) = (D0 test value - D7 test value) / D0 test value] × 100%;

[0263] b : Compare with D0 test value.

[0264] 7.4.1 Results of the doctor’s skin lesion count test for subjects in Group B: see Table 15.

[0265] Table 15 Results of skin lesion count test by doctors of group B

[0266]

[0267] a : Skin lesion regression rate (%) = (D0 test value - D7 test value) / D0 test value] × 100%;

[0268] b : Compare with D0 test value.

[0269] 8. Test Conclusion :

[0270] The acne removal effect of sample A is better than that of sample B.

[0271] Comparative Test Example 1 Grafting Rate of Salicylic Acid Grafted Chitosan Prepared by Different Grafting Methods 1. Take 2g salicylic acid, after 20g butanediol dissolves, add 2g refined deacetylated chitosan thereto, warm up to 70 ℃ and keep stirring for 3 hours, add 100g deionized water dilution thereto, then drip 1mol / L sodium hydroxide solution thereto at room temperature, the pH value of the regulating system is 9.5~10, and a large amount of solids are separated out at this time. After this solid is filtered by suction, wash it three times with absolute ethanol, until salicylic acid therein is washed with ethanol (judgment standard: drip 0.02mol / L ferric chloride solution in the washing liquid, if the color is purple, then it is not washed clean, need to continue washing, washing is completed until the ethanol washing liquid does not change color), obtain 281g washing liquid filtrate.

[0272] The salicylic acid concentration in the washing liquid filtrate was 0.544% as detected by the high performance liquid chromatography external standard method. Therefore, the mass of salicylic acid contained in the washing liquid was 1.529 g, that is, the mass of grafted salicylic acid was 0.471 g, and the grafting rate was 23.55%.

[0273] Obviously, there is a large amount of free salicylic acid in the above grafting reaction system, which is not suitable for direct use in the preparation of the skin external composition. The free salicylic acid must be removed, otherwise it will cause strong irritation to the skin.

[0274] 2. Take 2g of refined deacetylated chitosan, add 50g of deionized water, stir evenly, then add 1.8g of lactic acid, after the chitosan is dissolved, add 0.5g of zinc chloride and 0.1g of zinc oxide, and continue stirring for half an hour. Dissolve 0.5g of sodium tripolyphosphate in 5g of deionized water to obtain a sodium tripolyphosphate aqueous solution; then slowly add it dropwise to the reaction system. After the dripping is completed, continue stirring for half an hour, pour out, and the resulting suspension is the metal-chitosan catalyst.

[0275] Take 2g of salicylic acid and 20g of butanediol and stir them, heat them in a water bath to 70°C to dissolve the salicylic acid. Then add the prepared metal-chitosan catalyst, stir, keep warm and react for 3 hours, add 50 times by weight of deionized water to dilute, then add 1mol / L sodium hydroxide solution to the system at room temperature, adjust the pH value of the system to 9.5-10, and a large amount of solid will precipitate.

[0276] After the solid was filtered, it was washed three times with anhydrous ethanol until the salicylic acid therein was washed clean by the ethanol. (Judgment standard: 0.02 mol / L ferric chloride solution was added dropwise to the washing liquid. If the color was purple, it was not washed clean and it was necessary to continue washing until the ethanol washing liquid did not change color. The washing was completed) to obtain 410 g of washing liquid filtrate.

[0277] The high performance liquid chromatography external standard method was used for detection. The salicylic acid concentration in the washing liquid filtrate was 0.351%. Therefore, the mass of salicylic acid contained in the washing liquid was 1.439 g, that is, the mass of grafted salicylic acid was 0.561 g, and the grafting rate was 28.05%.

[0278] 3. Take 2g of refined deacetylated chitosan, add 50g of deionized water, stir evenly, then add 1.8g of lactic acid, after the chitosan is dissolved, add 0.5g of zinc chloride and 0.1g of zinc oxide, and continue stirring for half an hour. Dissolve 0.5g of sodium tripolyphosphate in 5g of deionized water to obtain a sodium tripolyphosphate aqueous solution; then slowly add it dropwise to the reaction system. After the dripping, continue stirring for half an hour, pour out, and freeze-dry according to conventional operations to obtain a loose and porous solid metal-chitosan catalyst.

[0279] Take 2g of salicylic acid and 20g of butanediol, stir, heat in a water bath to 70°C to dissolve the salicylic acid. Then add the prepared solid metal-chitosan catalyst in batches, stir, keep warm and react for 3 hours, add 100 times by weight of deionized water to dilute, then add 1mol / L sodium hydroxide solution to the system at room temperature, adjust the pH value of the system to 9.5-10, and a large amount of solids will precipitate.

[0280] After filtering the solid, wash it three times with anhydrous ethanol until the salicylic acid in it is washed clean by ethanol (judgment standard: add 0.02 mol / L ferric chloride solution to the washing liquid, if the color is purple, it is not washed clean, and it needs to be washed again until the ethanol washing liquid does not change color, then the washing is complete), and 338 g of washing liquid filtrate is obtained.

[0281] The salicylic acid concentration in the washing liquid filtrate was determined by the HPLC external standard method to be 0.186%. Therefore, the mass of salicylic acid contained in the washing liquid was 0.629 g, that is, the mass of grafted salicylic acid was 1.371 g, and the grafting rate was 68.55%.

[0282] In summary, the present invention provides a novel metal-chitosan catalyst for chitosan grafting with salicylic acid; the chitosan therein serves as both a carrier of the metal catalyst and a raw material for the salicylic acid grafting reaction; and the chitosan grafted with salicylic acid obtained by the reaction does not need to be separated and can be directly used as a raw material for a skin external composition. The skin external composition comprising the chitosan grafted with salicylic acid prepared by the present invention has good skin care and acne removal effects and is non-irritating to the skin, providing a new choice for patients with skin problems such as acne.

Claims

1. A method for preparing a metal-chitosan catalyst, comprising the following steps: I. Under acidic conditions, dissolve chitosan in 15 - 30 times its weight of water; II. Add a metal compound and stir; the metal compound is selected from one or more of zinc oxide, zinc sulfate, zinc chloride, magnesium chloride, and iron chloride; III. Dropwise add an aqueous sodium tripolyphosphate solution, and after dropping, continue to stir for more than 0.5 hours until the reaction ends; Wherein, The weight percentage concentration of the aqueous sodium tripolyphosphate solution is 5% - 20%; IV. Freeze-dry the reaction system to obtain the metal-chitosan catalyst; The weight parts of the chitosan, metal compound, and sodium tripolyphosphate are respectively: Chitosan 0.5 - 5 weight parts, metal compound 0.1 - 2 weight parts, sodium tripolyphosphate 0.1 - 2 weight parts; And independently, the weight part of the chitosan is not less than 2 times the weight part of the metal compound or the sodium tripolyphosphate.

2. The preparation method according to claim 1, Characterized in that, The chitosan is refined chitosan with a deacetylation degree of more than 95%.

3. The preparation method according to claim 2, Characterized in that, The refined chitosan with a deacetylation degree of more than 95% is prepared by the following method: Add the chitosan with a deacetylation degree of more than 95% to a 1% - 10% w / w acetic acid aqueous solution, stir to dissolve, so that the mass percentage content of chitosan is 1% - 10%, filter, dropwise add a 1% - 20% w / w sodium hydroxide solution to the filtrate, adjust the pH value of the system to 8 - 10, stand for more than 0.5 hours, carry out suction filtration, wash the filter cake with 70% - 95% w / w ethanol, and then vacuum dry to obtain.

4. The preparation method according to claim 3, Characterized in that, The concentration of the sodium hydroxide solution is 5% w / w.

5. The preparation method according to claim 3, Characterized in that, The vacuum drying parameters are a vacuum degree of 0.08 MPa - 0.09 MPa and a temperature of 50°C - 65°C.

6. The preparation method according to claim 1, Characterized in that, In step I, the acidic condition means pH = 5 - 6.

7. The preparation method according to claim 6, Characterized in that, In step I, add an acid to adjust pH = 5 - 6, and the acid is selected from one or more of hydrochloric acid, acetic acid, lactic acid, oxalic acid, and glycolic acid.

8. The preparation method according to claim 1, Characterized in that, The chitosan is dissolved in 20 - 25 times its weight of water.

9. The preparation method according to claim 1, Characterized in that, In step II, the metal compound is one or more of zinc oxide, zinc sulfate, zinc chloride, and magnesium chloride.

10. The preparation method according to claim 1 or 9, Characterized in that, In step II, after adding the metal compound, stir for at least half an hour.

11. The preparation method according to claim 1, Characterized in that, The weight percentage concentration of the aqueous sodium tripolyphosphate solution is 8% - 15%.

12. A metal-chitosan catalyst for salicylic acid grafting, which is prepared by the preparation method described in any one of claims 1 to 11.

13. The application of the metal-chitosan catalyst described in claim 12 in the preparation of salicylic acid-grafted chitosan, including adding the metal-chitosan catalyst batchwise to a non-aqueous solvent solution of salicylic acid and reacting at 60°C - 80°C until completion.

14. A preparation method of salicylic acid-grafted chitosan, including the following operations: Mix salicylic acid and a non-aqueous solvent, heat to 60°C - 80°C to dissolve salicylic acid; add the metal-chitosan catalyst described in claim 12 batchwise, stir, and keep warm until the reaction ends; Wherein, The weight ratio of chitosan to salicylic acid in the metal-chitosan catalyst is: 1:1 - 1:

2.

15. According to the preparation method described in claim 14, It is characterized in that, The reaction temperature is 70°C - 80°C.

16. According to the preparation method described in claim 14, It is characterized in that, The reaction time is 1 - 6 hours.

17. According to the preparation method described in claim 16, It is characterized in that, The reaction time is 1 - 3 hours.

18. A salicylic acid-grafted chitosan, which is prepared by the preparation method described in any one of claims 14 to 17.

19. A preparation method of salicylic acid-grafted chitosan for cosmetics, including the following operations: Mix salicylic acid and a monohydric or polyhydric lower aliphatic alcohol, heat to 60°C - 80°C to dissolve salicylic acid; add the metal-chitosan catalyst described in claim 12 or the metal-chitosan catalyst prepared by the preparation method described in any one of claims 1 to 11 batchwise, stir, and keep warm until the reaction ends; the weight ratio of chitosan to salicylic acid in the metal-chitosan catalyst is: 1:1 - 1:2; Wherein, When preparing the metal-chitosan catalyst, the metal compound is one or more of nano-zinc oxide, nano-zinc sulfate, nano-zinc chloride, and nano-magnesium chloride; the monohydric or polyhydric lower aliphatic alcohol is selected from one or any proportion of a variety of glycerol, propylene glycol, butylene glycol, pentylene glycol, ethanol, caprylyl glycol, isopropanol, hexylene glycol, methyl propylene glycol, ethoxydiglycol, and dipropylene glycol.

20. According to the preparation method described in claim 19, It is characterized in that, The weight ratio of the salicylic acid to the monohydric or polyhydric lower aliphatic alcohol is 1:5 - 1:

20.

21. According to the preparation method described in claim 20, It is characterized in that, The weight ratio of the salicylic acid to the monohydric or polyhydric lower aliphatic alcohol is 1:8 - 1:

12.

22. According to the preparation method described in claim 19, It is characterized in that, The reaction temperature is 70°C - 80°C.

23. According to the preparation method described in claim 19, It is characterized in that, The reaction time is 1 - 6 hours.

24. According to the preparation method described in claim 23, It is characterized in that, The reaction time is 1 - 3 hours.

25. A salicylic acid-grafted chitosan for cosmetics, which is prepared by the preparation method described in any one of claims 19 to 24.

26. A topical skin composition with a pH of 3 - 4, comprising the cosmetic use of salicylic acid - grafted chitosan as described in claim 25, further comprising a vitamin C derivative, vitamin E, and water; based on the total weight of the topical skin composition, the weight percentages of each component are: The cosmetic use of salicylic acid - grafted chitosan is 0.5% - 2%, the vitamin C derivative is 0.5% - 5%, vitamin E is 0.5% - 5%, and the balance is water; Wherein, The vitamin C derivative is selected from one or more of magnesium ascorbyl phosphate, ascorbyl tetraisopalmitate, 3 - O - ethyl ascorbic acid, and ascorbyl glucoside in any proportion.

27. A method for preparing the topical skin composition according to claim 26, Comprising: At 40°C - 50°C, mixing each component evenly, and adjusting the pH to 3 - 4 with a pH regulator to obtain the product.

28. According to the preparation method described in claim 27, It is characterized in that The pH regulator is selected from one or more of sodium hydroxide, potassium hydroxide, betaine, sodium bicarbonate, and triethanolamine in any proportion.

29. Use of the topical skin composition according to claim 26 or the topical skin composition prepared by the preparation method described in claim 27 or 28 in the preparation of a composition for treating skin acne.

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