A selenium disulfide lotion and method of making

Abstract

The application relates to the field of medicine or cosmetics, in particular to a selenium disulfide lotion and a preparation method, which comprises the following steps: S1, mixing a suspending agent, a pH regulator, a thickening agent and a solvent to prepare a mixture 1; mixing dodecyltetradecyl dimethyl benzyl ammonium chloride, selenium disulfide and a solvent to prepare a mixture 2; mixing glyceryl monoricinoleate and lauryl sulfate monoethanolamine to prepare a mixture 3; the mass percentage of the suspending agent in the selenium disulfide lotion is 0.90-1.30%, and the mass percentage of the thickening agent in the selenium disulfide lotion is 0.90-1.60%; S2, adding the mixture 2 into the mixture 3, and then adding the mixture 1, mixing, homogenizing to prepare the selenium disulfide lotion. The selenium disulfide lotion prepared by the method has good content uniformity and foaming performance.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical or cosmetic technology, specifically to a selenium disulfide lotion and its preparation method. Background Technology

[0002] Dandruff is a condition characterized by excessive flaking of the scalp due to the overgrowth of keratinocytes. Most current research suggests that dandruff originates from mild seborrheic dermatitis affecting the scalp. The generally accepted mechanism of seborrheic dermatitis is related to uninhibited proliferation of Malassezia, increased sebaceous gland activity, and individual immune dysfunction. Treatment primarily focuses on symptomatic relief, including degreasing, anti-inflammatory, antibacterial, and antipruritic therapies. Topical medications are widely used clinically due to their safety and reliable efficacy.

[0003] Selenium disulfide possesses pharmacological effects such as antifungal activity, anti-seborrheic activity, inhibition of Malassezia reproduction, and anti-epidermal hyperplasia. It is commonly used in 1% or 2.5% selenium disulfide shampoos to remove dandruff and treat seborrheic dermatitis of the scalp, with its dandruff-removing efficacy superior to ketoconazole. Therefore, selenium disulfide is widely used in the shampoo industry.

[0004] Selenium disulfide is almost insoluble in water or organic solvents, which means that it can only be dispersed in the matrix as a suspension during application. If the particle size of the selenium disulfide powder (e.g., greater than 50 μm) is large or the particle size distribution is wide, the dispersion uniformity of selenium disulfide in the matrix will be poor, the suspension will be unstable, and it will manifest as stratification in the formulation and drug aggregation when applied topically. If the particle size of selenium disulfide is small (e.g., less than 1 μm), it will increase the probability of skin barrier damage and increase the risk of skin toxicity from selenium disulfide lotion.

[0005] In existing technologies, changing the particle size of selenium disulfide can improve content uniformity, but the improvement effect is not very significant. To further improve content uniformity, existing technologies can also modify the preparation method of selenium disulfide detergents. However, due to the relatively complex production process of selenium disulfide detergents, improper preparation methods can easily lead to stratification or oxidation of selenium disulfide under high temperature or alkaline conditions, severely affecting its effectiveness as a cleaning agent. Furthermore, the foaming properties of selenium disulfide detergents prepared in existing technologies are unstable.

[0006] Therefore, to address the issues of poor uniformity of selenium disulfide content and unstable foaming performance mentioned above, further development of the preparation method is needed. Summary of the Invention

[0007] To address the problems of poor content uniformity and unstable foaming performance in existing selenium disulfide detergents, this invention provides a method for preparing selenium disulfide detergents. The selenium disulfide detergent prepared using this method exhibits improved content uniformity and foaming performance.

[0008] To achieve the above technical objectives, the present invention provides a method for preparing selenium disulfide detergent, the method comprising the following steps:

[0009] S1. Mix the suspending agent, pH adjuster, thickener, and solvent to obtain mixture 1; mix dodecyl-tetradecyl dimethyl betaine, selenium disulfide, and solvent to obtain mixture 2; mix glyceryl monoricinoleate and lauryl sulfate monoethanolamine salt to obtain mixture 3; the suspending agent accounts for 0.90-1.30% of the selenium disulfide detergent by mass, and the thickener accounts for 0.90-1.60% of the selenium disulfide detergent by mass.

[0010] S2. Add mixture 2 to mixture 3, then add mixture 1, mix, homogenize, and obtain selenium disulfide detergent.

[0011] The selenium disulfide detergent comprises 2.35-2.60% by mass of selenium disulfide, 0.75-1.30% by mass of pH adjuster, 1.90-6.00% by mass of dodecyl-tetradecyl dimethyl betaine, 1.10-1.80% by mass of ricinoleate, 37.00-43.00% by mass of lauryl sulfate monoethanolamine, and 41.35-55.60% by mass of the total mass of solvents in mixture 1 and mixture 2; and / or, 1.30-1.60% by mass of thickener.

[0012] The selenium disulfide detergent further includes one or more of a colorant and a flavoring agent; preferably, the colorant accounts for 0.90-1.10% of the selenium disulfide detergent by mass; preferably, the flavoring agent accounts for 0.20-0.50% of the selenium disulfide detergent by mass; preferably, the colorant is titanium dioxide; preferably, the flavoring agent is a fragrance.

[0013] The solvent in mixture 1 or mixture 2 is water; and / or the thickener is selected from one or more of sodium chloride, potassium chloride, ammonium chloride, and monoethanolamine chloride; and / or the pH adjuster is selected from one or more of citric acid, sodium dihydrogen phosphate hydrate, sodium hydroxide, citric acid, sorbic acid, and sodium bicarbonate.

[0014] The suspending agent is selected from calcium-based bentonite or sodium-based bentonite; preferably sodium-based bentonite.

[0015] In step S1, mixture 1 is prepared by mixing under the conditions of a stirring frequency of 45-55 Hz, a solvent temperature of 45-55℃, and a stirring time of 15-25 min; and / or, mixture 2 is prepared by mixing under the conditions of a stirring frequency of 5-15 Hz, a solvent temperature of 45-55℃, and a stirring time of 10-25 min; and / or, mixture 3 is prepared by mixing under the conditions of a stirring frequency of 5-20 Hz, a solvent temperature of 45-55℃, a stirring time of 5-15 min, and a vacuum degree of -0.06 to -0.08 MPa; and / or, the mass ratio of the solvent in mixture 1 to the solvent in mixture 2 is 3-3.5:1-1.5.

[0016] Based on the total mass of the selenium disulfide detergent as 100%, the pH adjuster comprises 0.50-1.00% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate; preferably, the pH adjuster comprises 0.50-0.60% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate.

[0017] The selenium disulfide detergent, by weight (100%), comprises 1.20% sodium bentonite, 0.96% titanium dioxide, 0.52% citric acid, 0.25% sodium dihydrogen phosphate dihydrate, 1.54% sodium chloride, 2.40% selenium disulfide, 41.35% lauryl sulfate monoethanolamine salt, 1.15% glyceryl monoricinoleate, 0.48% fragrance, and the balance being water. The selenium disulfide has a particle size D90 of 1–30 μm; preferably, a particle size D90 of 1–15 μm.

[0018] In step S2, under conditions of vacuum degree of -0.06 to -0.08 MPa and temperature of 45-55°C, mixture 2 is vacuum-drawn into mixture 3, and then mixture 1 is vacuum-drawn into mixture 3; and / or, the mixing is carried out under conditions of stirring frequency of 8-12 Hz and stirring time of 10-30 min; and / or, the homogenization step includes homogenizing for 20-30 min under conditions of vacuum degree of -0.06 to -0.08 MPa, temperature of 45-55°C, stirring frequency of 25-35 Hz and homogenization frequency of 45-55 Hz, and then homogenizing for 20-30 min under conditions of stirring frequency of 40-45 Hz and homogenization frequency of 15-25 Hz.

[0019] The homogenization process further includes a filling step; preferably, the filling amount is 104-110g / bottle, and the filling temperature is 10-30℃.

[0020] The present invention also provides a method for preparing selenium disulfide detergent.

[0021] The technical solution of the present invention has the following beneficial effects:

[0022] (1) The present invention provides a method for preparing a selenium disulfide detergent, the method comprising the following steps: S1, mixing a suspending agent, a pH adjuster, a thickener and a solvent to obtain mixture 1; mixing dodecyl-tetradecyl dimethyl betaine, selenium disulfide and a solvent to obtain mixture 2; mixing glyceryl monoricinoleate and lauryl sulfate monoethanolamine salt to obtain mixture 3; wherein the suspending agent accounts for 0.90-1.30% of the mass of the selenium disulfide detergent, and the thickener accounts for 0.90-1.60% of the mass of the selenium disulfide detergent; S2, adding mixture 2 to mixture 3, then adding mixture 1, mixing, homogenizing, to obtain the selenium disulfide detergent. This invention prepares mixture 2 by mixing a specific surfactant, dodecyl dimethyl betaine, with selenium disulfide and a solvent. Then, mixture 2 and mixture 1 are mixed with mixture 3, which is prepared by a specific glyceryl monoricinoleate and lauryl sulfate monoethanolamine salt. The mixture is homogenized to ensure the uniformity of selenium disulfide content during the preparation process and to improve the stability of foaming performance. By strictly controlling the particle size of selenium disulfide and the conditions during the preparation process, the quality of the prepared selenium disulfide detergent is stable.

[0023] (2) The present invention provides a method for preparing a selenium disulfide detergent, wherein the thickener is preferably 1.30-1.60%, and the viscosity of the obtained selenium disulfide detergent is more suitable.

[0024] (3) The present invention provides a method for preparing selenium disulfide detergent. In step S1, the temperature of the solvent is controlled at 45-55℃. In step S2, the temperature of the solvent is controlled at 45-55℃ and the vacuum degree is -0.06 to -0.08MPa, so that the mixing is more uniform and the content uniformity of selenium disulfide detergent is improved.

[0025] (4) The present invention provides a method for preparing a selenium disulfide detergent, wherein the pH adjuster comprises 0.50-1.00% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate, based on the total mass of the selenium disulfide detergent as 100%; preferably, the pH adjuster comprises 0.50-0.60% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate, which further improves the quality of the selenium disulfide detergent. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This refers to the preparation steps of the selenium disulfide detergent in Example 1 of the present invention. Detailed Implementation

[0028] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0029] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0030] Information on the bentonite involved in this invention is shown in Table 1 below.

[0031] Table 1 Bentonite Types

[0032] name Certified Merchants batch number Calcium-based bentonite Inner Mongolia Ningcheng Tianyu 2011201 Sodium bentonite American Colloid Company 59902NFL286 (HV type)

[0033] The particle size of the selenium disulfide raw material used in this invention was tested. The method was to use a Malvern 3000 laser particle size analyzer to determine the particle size by dry method. The dispersing gas pressure was 0.4 MPa. The particle size test results of four batches of raw materials are shown in Table 2 below. The particle size of each batch is basically the same, with D90≤15um.

[0034] Table 2. Particle size determination results

[0035] batch number D10 / um D50 / um D90 / um 1 2.50 5.27 10.87 2 2.25 4.79 10.0 3 2.18 4.68 9.80 4 2.51 5.26 9.80

[0036] Example 1

[0037] This embodiment provides a method for preparing selenium disulfide detergent. The formula is shown in Table 3, with a total mass of 312 kg and the remainder being water.

[0038] Table 3 Formula Weight

[0039] materials Example 1 (kg) Sodium bentonite 3.75 Titanium dioxide 3.00 Citric acid 1.62 Sodium dihydrogen phosphate dihydrate 0.78 Sodium chloride 4.80 Dodecyl dimethyl betaine 6.00 Selenium disulfide (particle size D90 is 10.87 μm) 7.50 Lauryl sulfate monoethanolamine salt 129.00 glyceryl monoricinoleate 3.60 essence 1.50

[0040] The preparation process is as follows: Figure 1As shown, the specific preparation steps are as follows:

[0041] S1. Set the jacket temperature of mixing tank 1 to 50℃. Weigh 70% of the formula amount of water and add it to mixing tank 1. Under the conditions of stirring frequency of 50Hz and water temperature of 50℃, add bentonite and titanium dioxide, and stir for 20 minutes. Weigh sodium dihydrogen phosphate dihydrate and sodium chloride and add them to citric acid. After mixing and stirring, add them to the mixed solution of bentonite and titanium dioxide to obtain mixture 1. Set the jacket temperature of mixing tank 2 to 50℃. Weigh 30% of the formula amount of water and add it to mixing tank 2. Under the conditions of stirring frequency of 50Hz and water temperature of 50℃, add bentonite and titanium dioxide, and stir for 20 minutes. Under conditions of 8 Hz, dodecyl-tetradecyl dimethyl betaine was added, and after stirring for 15 min, selenium disulfide (batch number 1, particle size D90 of 10.87 μm) was added and stirred for 20 min to obtain mixture 2; the jacket temperature of the emulsification tank was set to 50 ℃, lauryl sulfate monoethanolamine salt was weighed into the emulsification tank, and then glyceryl monoricinoleate and fragrance were added. Under conditions of vacuum degree of -0.07 MPa, solution temperature of 50 ℃, and stirring frequency of 10 Hz, the mixture was stirred for 10 min to obtain mixture 3;

[0042] S2. Under conditions of vacuum degree -0.07MPa and temperature of 50℃, mixture 2 is vacuum-drawn into mixture 3, and then mixture 1 is vacuum-drawn into mixture 3. The mixture is then stirred for 15 minutes at a stirring frequency of 10Hz. Homogenize for 20 minutes under conditions of vacuum degree -0.07MPa, temperature of 50℃, stirring frequency of 30Hz, and homogenization frequency of 50Hz. Then, homogenize for 30 minutes under conditions of vacuum degree -0.07MPa, temperature of 50℃, stirring frequency of 40Hz, and homogenization frequency of 20Hz, and then cool the solution to 20℃.

[0043] S3. Under the condition of stirring frequency of 15Hz, the selenium disulfide detergent in the emulsification tank is filled with 104-110g / bottle at a filling temperature of 20℃ to obtain the selenium disulfide detergent.

[0044] Example 2

[0045] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 4, and the remainder is water.

[0046] Table 4 Formula Weight

[0047]

[0048] The preparation method is the same as in Example 1.

[0049] Example 3

[0050] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 4, and the remainder is water. The preparation method is the same as in Example 1.

[0051] Example 4

[0052] This embodiment provides a selenium disulfide detergent. The formula is shown in Table 4, with a total mass of 312 kg and the remainder being water. The preparation method is the same as in Example 1.

[0053] Example 5

[0054] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 5, and the remainder is water. The preparation method is the same as in Example 1.

[0055] Table 5 Formula Weight

[0056] materials Example 5(g) Calcium-based bentonite 84.00 Titanium dioxide 70.00 Citric acid 37.80 Sodium dihydrogen phosphate dihydrate 18.20 Sodium chloride 112.00 Dodecyl dimethyl betaine 140.00 Selenium disulfide (particle size D90 is 10.87 μm) 175.00 Lauryl sulfate monoethanolamine salt 3010.00 glyceryl monoricinoleate 84.00 essence 35.00

[0057] Example 6

[0058] This embodiment provides a selenium disulfide detergent. The formula is shown in Table 6, with a total mass of 312 kg and the remainder being water. The preparation method is the same as in Example 1.

[0059] Table 6 Formula Weight

[0060]

[0061] Example 7

[0062] This embodiment provides a selenium disulfide detergent. The formula is shown in Table 6, with a total mass of 312 kg and the remainder being water. The preparation method is the same as in Example 1.

[0063] Example 8

[0064] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 6, and the remainder is water. The preparation method is the same as in Example 1.

[0065] Example 9

[0066] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 7, and the remainder is water. The preparation method is the same as in Example 1.

[0067] Table 7 Formula Weight

[0068]

[0069] Example 10

[0070] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 7, and the remainder is water. The preparation method is the same as in Example 1.

[0071] Example 11

[0072] This embodiment provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 7, and the remainder is water. The preparation method is the same as in Example 1.

[0073] Comparative Example 1

[0074] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 8, and the remainder is water. The preparation method is the same as in Example 1.

[0075] Table 8 Formula Weight

[0076]

[0077]

[0078] Comparative Example 2

[0079] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 8, and the remainder is water. The preparation method is the same as in Example 1.

[0080] Comparative Example 3

[0081] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 8, and the remainder is water. The preparation method is the same as in Example 1.

[0082] Comparative Example 4

[0083] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 8, and the remainder is water. The preparation method is the same as in Example 1.

[0084] Comparative Example 5

[0085] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 8, and the remainder is water. The preparation method is the same as in Example 1.

[0086] Comparative Example 6

[0087] This comparative example provides a selenium disulfide detergent with the same formulation and preparation method as Example 1. The only difference is that in step S1, "adding dodecyl-tetradecyl dimethyl betaine" is replaced with "adding dodecyl-tetradecyl dimethyl betaine and lauryl sulfate monoethanolamine salt" during the preparation of mixture 2, and lauryl sulfate monoethanolamine salt is not added during the preparation of mixture 3.

[0088] Comparative Example 7

[0089] This comparative example provides a selenium disulfide detergent with the same formulation and preparation method as Example 1. The only difference is that in step S1, "adding dodecyl-tetradecyl dimethyl betaine" is replaced with "adding dodecyl-tetradecyl dimethyl betaine and glyceryl monoricinoleate" in the preparation of mixture 2, and glyceryl monoricinoleate is not added in the preparation of mixture 3.

[0090] Comparative Example 8

[0091] This comparative example provides a selenium disulfide detergent with the same formulation and preparation method as Example 1. The only difference is that in step S1, "adding dodecyl-tetradecyl dimethyl betaine" is replaced with "adding glyceryl monoricinoleate and lauryl sulfate monoethanolamine salt" in the preparation of mixture 2, and "weighing lauryl sulfate monoethanolamine salt into the emulsification tank and then adding glyceryl monoricinoleate" is replaced with "weighing dodecyl-tetradecyl dimethyl betaine into the emulsification tank" in the preparation of mixture 3.

[0092] Comparative Example 9

[0093] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg, the formulation of which is shown in Table 9, and the remainder being water. The preparation method is basically the same as in Example 1, except that dodecyl-tetradecyldimethylbetaine was not added during the preparation of mixture 2.

[0094] Table 9 Formula Weight

[0095]

[0096] Comparative Example 10

[0097] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg, the formulation of which is shown in Table 9, and the remainder being water. The preparation method is basically the same as in Example 1, except that glyceryl monoricinoleate was not added during the preparation of mixture 3.

[0098] Comparative Example 11

[0099] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg, and the formulation is shown in Table 9, with the remainder being water. The preparation method is basically the same as in Example 1, except that lauryl sulfate monoethanolamine salt was not added during the preparation of mixture 3.

[0100] Comparative Example 12

[0101] This comparative example provides a selenium disulfide detergent with the same formulation and preparation method as Example 1. The only difference is that in step S2, "vacuum-drawing mixture 2 into mixture 3 and then vacuum-drawing mixture 1 into mixture 3" is replaced with "vacuum-drawing mixture 1 into mixture 3 and then vacuum-drawing mixture 2 into mixture 3".

[0102] According to the determination method of selenium disulfide detergent in the Chinese Pharmacopoeia (2020 edition), the content of selenium disulfide was found to be 90.78%. The reason is that during the preparation process, mixture 1 was transferred first and then mixture 2. During the vacuum transfer process, some of the selenium disulfide in mixture 2 splashed onto the stirring paddle and pot wall of the equipment, and could not actually enter the system. As a result, the actual amount of selenium disulfide dissolved in the system was reduced, resulting in a lower overall content, which could not meet the content detection range requirements of selenium disulfide detergent.

[0103] Comparative Example 13

[0104] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg, the formulation of which is shown in Table 10, and the remainder being water. Its preparation method is the same as in Example 1.

[0105] Table 10 Formula Weight

[0106]

[0107] Comparative Example 14

[0108] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 10, and the remainder is water. The preparation method is the same as in Example 1.

[0109] Comparative Example 15

[0110] This comparative example provides a selenium disulfide detergent, with a total mass of 7 kg. The formula is shown in Table 10, and the remainder is water. The preparation method is the same as in Example 1.

[0111] Comparative Example 16

[0112] This comparative example provides a selenium disulfide detergent, with a formulation and preparation method basically the same as Comparative Example 15, the only difference being that calcium-based bentonite is used instead of sodium-based bentonite.

[0113] Experimental Example 1

[0114] Three batches of selenium disulfide detergent were prepared by repeating the preparation method of Example 1. The properties, content, viscosity, and pH values ​​of the three batches of selenium disulfide detergent prepared by the method of Example 1, and two different batches of commercially available selenium disulfide detergent (reference preparation 1 and reference preparation 2) shown in Table 11 were observed, determined, and tested. The specific methods are as follows:

[0115] Viscosity testing method: Place the selenium disulfide detergent in an IQ type rheometer, with a rotor model of C35, a gap of 0.1 mm, CR mode, and a shear rate γ = 100.0 s. -1 Viscosity was measured using a rotational viscometer under the conditions of scanning time t = 2 min and temperature T = 25℃.

[0116] pH value was determined according to the pH value determination method in the Chinese Pharmacopoeia (2020 edition).

[0117] The content determination method was carried out in accordance with the determination method of selenium disulfide detergent in the Chinese Pharmacopoeia (2020 edition).

[0118] Table 11 Information on the reference formulation

[0119]

[0120] The test results are shown in Table 12. Compared with the two commercially available reference preparations, the selenium disulfide detergent prepared by the method of Example 1 is an orange-yellow viscous suspension, and the batch-to-batch coefficients of variation of viscosity and content are significantly reduced, indicating that the method of the present invention can be used to prepare a selenium disulfide detergent with better content uniformity.

[0121] Table 12 Test Results

[0122]

[0123] Experimental Example 2

[0124] This experimental example observes (appearance), determines the content, tests the viscosity, and tests the pH value of the selenium disulfide detergents prepared in each embodiment and comparative example. The test methods are the same as those in Experimental Example 1.

[0125] The test results are shown in Table 13 below. Combined with Table 12, and considering all indicators, the viscosity of the selenium disulfide detergent prepared in Examples 1-11 is between 400-700 mPa·s. It is an orange-yellow viscous suspension or an orange-yellow viscous suspension with lower viscosity. It has the advantages of not separating and uniform drug dispersion.

[0126] Compared to Examples 1 and 8 and Comparative Examples 1-5, Examples 1 and 8, by controlling the proportion of sodium chloride within the range of 0.90-1.60%, produced selenium disulfide detergents with viscosities between 400-700 mPa·s and uniform drug dispersion. In contrast, the selenium disulfide detergents prepared in Comparative Examples 1-5 had viscosities that were either too low or too high. Compared to Examples 6-7, Example 1, by limiting the proportion of sodium chloride within a preferred range, further controlled the viscosity of selenium disulfide within the range of 550-700 mPa·s.

[0127] Compared with Comparative Examples 13-15, Examples 1-3, by controlling the proportion of sodium-based bentonite within the range of 0.90-1.30%, produced selenium disulfide detergents with a viscosity between 400-700 Pa·s, exhibiting the characteristics of non-stratification and uniform drug dispersion. Compared with Examples 5, the selenium disulfide detergent prepared in Example 3 had a more suitable viscosity and exhibited a viscous suspension; therefore, sodium-based bentonite was preferred.

[0128] Compared with Comparative Examples 6-8, the selenium disulfide detergent prepared by Example 1 using a specific mixing method does not separate into layers, has uniform drug dispersion, and presents as a viscous suspension.

[0129] Table 13 Test Results

[0130]

[0131]

[0132] Experimental Example 3

[0133] Foaming performance tests were conducted on three batches of selenium disulfide detergent prepared using the method of Example 1, as well as the commercially available selenium disulfide detergent (reference preparation 1) shown in Table 11 and the selenium disulfide detergent prepared by comparative examples 9-11. Test method: The same amount of selenium disulfide detergent was taken, and its foaming amount at 0 min and 5 min was measured using a Roche foam apparatus. The test results are shown in Table 14 below. Compared with comparative examples 9-11 and the commercially available reference preparation, the three batches of selenium disulfide detergent prepared using the method of Example 1 showed stronger foaming performance at 0 min and better foaming amount. Even after 5 min, the foam remained stable, indicating that the foaming performance and foam stability of the selenium disulfide detergent prepared using the method of this invention have been improved, enhancing the consumer's user experience.

[0134] Table 14 Test Results

[0135]

[0136] Experiment Example 4

[0137] The content of selenium disulfide detergent prepared using the method of Example 1 was determined according to the determination method for selenium disulfide detergent in the Chinese Pharmacopoeia (2020 edition) during the preparation and filling stages. Samples were taken from the upper layer (one-third of the way from the liquid surface) of the emulsification tank, the lower layer (one-third of the way from the bottom of the emulsification tank), the first 10 bottles before filling (average content result), the 10 bottles at the halfway point of filling (average content result), and the last 10 bottles after filling (average content result). The results are shown in Table 15. Compared with Comparative Examples 4 and 5, the content uniformity of the three batches of selenium disulfide detergent prepared using the method of Example 1 was significantly improved in both the preparation and filling stages.

[0138] Table 15 Preparation and Filling Stages - Content (%)

[0139]

[0140] Experimental Example 5

[0141] Three batches of selenium disulfide detergent prepared using the method in Example 1 were placed in a stability test chamber for stability testing. Specifically, accelerated stability was investigated at 40°C and 25% relative humidity; long-term stability was investigated at 25°C and 40% relative humidity; and intermediate-condition stability was investigated at 30°C and 35% relative humidity. The content was determined according to the method for selenium disulfide detergent in the Chinese Pharmacopoeia (2020 edition) as an indicator of stability. The content test results are shown in Table 16 below. The RSD% was less than 1% for all batches. Under accelerated, long-term, and intermediate-condition stability tests, the content of the selenium disulfide detergent remained relatively stable after 6 months, indicating that the selenium disulfide detergent has good stability within 6 months.

[0142] Table 16 Stability Study Results - Content (%)

[0143]

[0144] Experimental Example 6

[0145] The fill weight values ​​of three batches of selenium disulfide detergent prepared using the method of Example 1 were tested. The selenium disulfide detergent at different stages of filling was weighed using a balance: the first stage of filling (3 bottles randomly selected from the first 10 bottles), the middle stage of filling (3 bottles randomly selected from 10 bottles at half the total number of bottles), and the last stage of filling (3 bottles randomly selected from the last 10 bottles). The results are shown in Table 17 below. The fill weight values ​​between batches and at different filling stages of the same batch were relatively stable, with RSD% all less than 2%. This indicates that the three batches of selenium disulfide detergent prepared using the method of Example 1 have good liquid fill weight stability due to their high content uniformity and the absence of liquid stratification.

[0146] Table 17. Fill Weight Test Results (g)

[0147]

[0148] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a selenium disulfide detergent, characterized in that, The preparation method includes the following steps: S1. Mix the suspending agent, pH adjuster, thickener, and solvent to obtain mixture 1; mix dodecyl-tetradecyl dimethyl betaine, selenium disulfide, and solvent to obtain mixture 2; mix glyceryl monoricinoleate and lauryl sulfate monoethanolamine salt to obtain mixture 3; the suspending agent accounts for 0.90-1.30% of the selenium disulfide detergent by mass, and the thickener accounts for 1.30-1.60% of the selenium disulfide detergent by mass; S2. Add mixture 2 to mixture 3, then add mixture 1, mix, homogenize, and obtain selenium disulfide detergent; The selenium disulfide detergent comprises 2.35-2.60% by mass of selenium disulfide, 0.75-1.30% by mass of pH adjuster, 1.90-6.00% by mass of dodecyl-tetradecyl dimethyl betaine, 1.10-1.80% by mass of ricinoleate, 37.00-43.00% by mass of lauryl sulfate monoethanolamine, and 41.35-55.60% by mass of the solvent in mixture 1 and mixture 2. The solvent in mixture 1 or mixture 2 is water; the thickener is selected from sodium chloride and / or potassium chloride; the suspending agent is selected from calcium-based bentonite or sodium-based bentonite; the particle size D90 of selenium disulfide is 1~15μm; Based on the total mass of the selenium disulfide detergent as 100%, the pH adjuster includes 0.50-1.00% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate.

2. The method for preparing selenium disulfide detergent according to claim 1, characterized in that, The selenium disulfide detergent also includes one or more of colorants and flavorings.

3. The method for preparing selenium disulfide detergent according to claim 2, characterized in that, The colorant accounts for 0.90-1.10% of the mass of the selenium disulfide detergent; And / or, the flavoring agent accounts for 0.20-0.50% of the selenium disulfide detergent by mass; And / or, the colorant is titanium dioxide; And / or, the flavoring agent is a fragrance.

4. The method for preparing selenium disulfide detergent according to claim 1 or 2, characterized in that, In step S1, mixture 1 is prepared by mixing under the conditions of a stirring frequency of 45-55 Hz, a solvent temperature of 45-55℃, and a stirring time of 15-25 min; and / or, mixture 2 is prepared by mixing under the conditions of a stirring frequency of 5-15 Hz, a solvent temperature of 45-55℃, and a stirring time of 10-25 min; and / or, mixture 3 is prepared by mixing under the conditions of a stirring frequency of 5-20 Hz, a solvent temperature of 45-55℃, a stirring time of 5-15 min, and a vacuum degree of -0.06 to -0.08 MPa; and / or, the mass ratio of the solvent in mixture 1 to the solvent in mixture 2 is 3~3.5:1~1.

5.

5. The method for preparing selenium disulfide detergent according to claim 1, characterized in that, The pH adjuster comprises 0.50-0.60% citric acid and 0.24-0.28% sodium dihydrogen phosphate dihydrate.

6. The method for preparing selenium disulfide detergent according to claim 1 or 2, characterized in that, In step S2, under conditions of vacuum degree of -0.06 to -0.08 MPa and temperature of 45-55°C, mixture 2 is vacuum-drawn into mixture 3, and then mixture 1 is vacuum-drawn into mixture 3; and / or, the mixing is carried out under conditions of stirring frequency of 8-12 Hz and stirring time of 10-30 min; and / or, the homogenization step includes homogenizing for 20-30 min under conditions of vacuum degree of -0.06 to -0.08 MPa, temperature of 45-55°C, stirring frequency of 25-35 Hz and homogenization frequency of 45-55 Hz, and then homogenizing for 20-30 min under conditions of stirring frequency of 40-45 Hz and homogenization frequency of 15-25 Hz.

7. A method for preparing selenium disulfide detergent according to any one of claims 1-6.

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