A quaternary ammonium salt leave-on disinfectant gel with skin mildness and a method of making the same

Abstract

This invention discloses a quaternary ammonium salt no-rinse disinfectant gel with skin-friendly properties. The quaternary ammonium salt no-rinse disinfectant gel contains the following raw materials and their weight parts: quaternary ammonium salt 0.1-0.5 parts, glycolipid surfactant 0.02-0.3 parts, gel matrix 0.5-1 parts, pH adjuster 0.1-0.5 parts, and deionized water 97-99.3 parts. The formulation of this invention is characterized by quick-drying, refreshing and odorless, non-toxic and harmless, and mild.

Description

Technical Field

[0001] This invention relates to the field of daily chemical technology, and in particular to a quaternary ammonium salt no-rinse disinfectant gel with skin-mild properties and its preparation method. Background Technology

[0002] Among hand sanitizing products, no-rinse sanitizers have advantages in terms of usability and portability, and have a wide range of consumer demand in various occasions. This makes no-rinse sanitizers have a broader consumer market than traditional hand sanitizers and disinfectants.

[0003] Current no-rinse disinfectant products are mainly divided into two types based on their active disinfectant ingredients: ethanol and quaternary ammonium salts. Ethanol-based no-rinse disinfectants pose a certain flammability risk, limiting their use on high-speed trains and airplanes. In contrast, disinfectants with quaternary ammonium salts as the active ingredient have lower active ingredient content, better bactericidal effects, and are safer and more reliable. However, as a cationic surfactant, quaternary ammonium salts neutralize the skin's negative charge upon contact, altering the skin's surface charge and affecting the barrier properties of the stratum corneum and skin permeability. Quaternary ammonium salts are significantly more irritating to the skin than anionic and nonionic surfactants, primarily damaging the skin's stratum corneum's water-retention capacity, potentially leading to decreased skin moisture content, increased transepidermal water loss, and even redness, swelling, and itching. Furthermore, because no-rinse disinfectant products dry quickly after use and do not require rinsing, repeated use can easily raise consumer concerns about skin irritation.

[0004] The development of quaternary ammonium salt-based rinse-free disinfectants is relatively recent, and research on improving the gentleness of formulations to reduce skin irritation from quaternary ammonium salts is still lacking. Current technologies sometimes add moisturizing ingredients such as glycerin and propylene glycol to the formulation to achieve hand-care effects. However, related studies have found that moisturizers like propylene glycol increase skin permeability, which may further enhance skin irritation in the presence of quaternary ammonium salts. Some technologies improve skin gentleness by adding plant-derived extracts, but the mechanisms are unclear, thus hindering further improvements in the gentleness of disinfectants. Therefore, developing skin-friendly quaternary ammonium salt-based rinse-free disinfectants presents a significant technical challenge. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, the applicant of this invention provides a quaternary ammonium salt no-rinse disinfectant gel with skin-friendly properties and its preparation method. The formulation of this invention is characterized by quick-drying, refreshing and odorless, non-toxic and harmless, and gentle on the skin.

[0006] The technical solution of the present invention is as follows:

[0007] A skin-friendly quaternary ammonium salt no-rinse disinfectant gel, wherein the raw materials contained in the quaternary ammonium salt no-rinse disinfectant gel and the weight parts of each raw material are as follows:

[0008]

[0009] The quaternary ammonium salt is one or a mixture of two of the following: single-chain quaternary ammonium salt and double-chain quaternary ammonium salt.

[0010] The single-chain quaternary ammonium salt is one or more of benzalkonium chloride, benzalkonium bromide, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, dodecyl-dimethyl-2-phenoxyethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, and tetradecyldimethylbenzylammonium bromide.

[0011] The double-chain quaternary ammonium salt is one or more of the following: dioctyl dimethyl ammonium chloride, dioctyl dimethyl ammonium bromide, didecyl dimethyl ammonium chloride, didecyl dimethyl ammonium bromide, didodecyl dimethyl ammonium bromide, didodecyl dimethyl ammonium chloride, ditetradecyl dimethyl ammonium chloride, and ditetradecyl dimethyl ammonium bromide.

[0012] The glycolipid surfactant is one or more of the following: rhamnolipin, sophorolipid, mannose erythritol lipolipin, trehalolipid, succinyl-trehalolipid, and cellobiolipid.

[0013] The gel matrix is ​​one or more of methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, and hydroxypropylcellulose.

[0014] The pH adjuster is an organic base or a basic amino acid. Preferably, the pH adjuster is one or more of triethanolamine, monoethanolamine, ethylenediamine, and arginine.

[0015] In a preferred embodiment, the raw materials and their weight proportions in the quaternary ammonium salt hand sanitizer gel are as follows:

[0016]

[0017]

[0018] A method for preparing the skin-friendly quaternary ammonium salt no-rinse disinfectant gel, wherein the preparation method comprises:

[0019] (1) Take 0.1-0.5 parts of quaternary ammonium salt and mix it thoroughly with 0.02-0.3 parts of glycolipid surfactant until the mixture is homogeneous;

[0020] (2) Add 80 parts of deionized water to the product obtained in step (1) while stirring to fully dissolve each component until the solution is homogeneous, clear and free of insoluble matter.

[0021] (3) Heat the product obtained in step (2) to above 50°C, maintain the temperature and add 0.5-1 part of gel matrix, gradually cool down to room temperature while stirring, and maintain the stirring speed at 120 rpm until gel is formed.

[0022] (4) Add 0.1-0.5 parts of pH adjuster to adjust the pH of the solution to 4-7 to the product obtained in step (3), and add deionized water to make the mass fraction of the system reach 100 parts. Continue stirring until the system is transparent and uniform to obtain the quaternary ammonium salt no-rinse disinfectant gel.

[0023] The beneficial technical effects of this invention are as follows:

[0024] This invention addresses the skin irritation caused by the electrostatic interaction between quaternary ammonium cationic surfactants and the skin. By introducing glycolipid surfactants to competitively adsorb the quaternary ammonium salt, the amount of quaternary ammonium salt adsorbed on the skin is reduced, thus imparting a gentler skin-friendly quaternary ammonium salt disinfectant gel. Instrumental testing shows that it inhibits the decrease in skin moisture content caused by quaternary ammonium salt, inhibits the increase in transepidermal water loss caused by quaternary ammonium salt, and reduces the increase in skin friction caused by quaternary ammonium salt. Animal experiments show that it reduces skin irritation in rabbits.

[0025] Glycolipid surfactants are nonionic surfactants derived from microbial fermentation. Their molecular structure contains multiple hydroxyl groups, resulting in stronger binding affinity to oxygen-containing groups on the skin surface. Compared to general nonionic surfactants, they are more skin-friendly and gentler. As a novel type of biosynthetic surfactant, glycolipids are used in medicine and pharmaceuticals due to their unique biological properties and biodegradability. This invention reveals that the introduction of glycolipid surfactants can significantly reduce the skin irritation caused by quaternary ammonium salts.

[0026] The quaternary ammonium salt-based no-rinse gel formulation proposed in this invention has a high kill rate against common pathogens such as Escherichia coli, Staphylococcus aureus, and Candida albicans. The prepared gel disinfectant is transparent, colorless, odorless, and has good stability. Attached Figure Description

[0027] Figure 1 The graph shows the decrease in skin moisture content for the examples and comparative examples;

[0028] Figure 2 The graph shows the increase in transdermal water loss for the examples and comparative examples;

[0029] Figure 3 The graph shows the increase in skin friction force in the examples and comparative examples. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the embodiments.

[0031] Examples 1-4

[0032] A method for preparing the skin-friendly quaternary ammonium salt no-rinse disinfectant gel, wherein the preparation method comprises:

[0033] (1) Take 0.1-0.5 parts of quaternary ammonium salt and mix it thoroughly with 0.02-0.3 parts of glycolipid surfactant until the mixture is homogeneous;

[0034] (2) Add 80 parts of deionized water to the product obtained in step (1) while stirring to fully dissolve each component until the solution is homogeneous, clear and free of insoluble matter.

[0035] (3) Heat the product obtained in step (2) to above 50°C, maintain the temperature and add 0.7 parts of gel matrix, gradually cool down to room temperature while stirring, and maintain the stirring speed at 120 rpm until gel is formed;

[0036] (4) Add 0.1-0.5 parts of pH adjuster to adjust the pH of the solution to 4-7 to the product obtained in step (3), and add deionized water to make the mass fraction of the system reach 100 parts. Continue stirring until the system is transparent and uniform to obtain the disinfectant gel.

[0037] The raw materials and their quantities in Examples 1-3 are shown in Table 1.

[0038] Table 1

[0039]

[0040]

[0041] Comparative Examples 1-3

[0042] A method for preparing a quaternary ammonium salt no-rinse disinfectant gel is described, which is the same as in Examples 1-4, except that the glycolipid surfactant is replaced. The specific composition is shown in Table 2.

[0043] Table 2

[0044]

[0045] Test example:

[0046] (1) Disinfection effect test;

[0047] The sterilization efficiency was tested using the suspension method according to standard 2.2.1.4 of the "Disinfection and Hygiene Standard (2002 Edition)". The test results are shown in Table 3.

[0048] Table 3

[0049]

[0050]

[0051] As shown in Table 3, Examples 1-4 of the present invention achieved a kill log of over 5 against Escherichia coli and Staphylococcus aureus within 5 minutes, and a kill log of over 4 against Candida albicans. Among the comparative examples, only Comparative Example 1, with a high quaternary ammonium salt content, showed a bactericidal effect comparable to the examples. The kill log values ​​of Comparative Examples 2 and 3, with a quaternary ammonium salt content of 0.1%, were slightly lower than those of Example 2, which also had a quaternary ammonium salt content of 0.1%. This indicates that the introduction of glycolipids has a certain promoting effect on the disinfection and sterilization of quaternary ammonium salts. This result may be due to the fact that glycolipid surfactants derived from microbial fermentation have a certain natural antibacterial function, thus facilitating the elimination of contaminating bacteria during fermentation and allowing microorganisms to become the dominant species.

[0052] (2) Human skin mildness test;

[0053] (2.1) Testing Instruments

[0054] Skin moisture content was measured using a Corneometer multi-probe skin testing system manufactured by CK (Courage+Khazaka electronic GmbH) in Germany; transdermal water loss was measured using a Tewameter skin moisture loss tester manufactured by CK in Germany; and friction was measured using a Frictionmeter coefficient of friction tester manufactured by CK in Germany.

[0055] (2.2) Test Method

[0056] Human trials were conducted on 10 volunteers. Four 1.5cm x 1.5cm areas were marked on the inside of the arm. A cotton swab was used to apply the test disinfectant gel sample evenly to each of the four areas. After waiting 1 minute for the gel to dry, the sample was applied again, for a total of 10 times. Skin moisture content, transepidermal water loss, and friction were then measured using various probes. The test results are shown in Table 4.

[0057] Table 4

[0058]

[0059]

[0060] After application, the volunteers' skin showed a trend of decreased skin moisture content, increased transepidermal water loss, and increased skin friction, indicating that the disinfectant gel was irritating to the skin. The degree of change in these three indicators reflects the level of skin irritation of the formula; the smaller the change in these three indicators, the milder the formula. To more intuitively illustrate the changes in these three indicators, bar graphs (1-3) were plotted to show the decrease in skin moisture content, increase in transepidermal water loss, and increase in skin friction in the examples and comparative examples. As can be seen from the graphs, the changes in skin moisture content, transepidermal water loss, and skin friction in comparative examples 1-3 were significantly greater than those in the example, demonstrating stronger skin irritation. Therefore, the comparative examples showed poor skin mildness.

[0061] (3) Rabbit skin irritation test;

[0062] The experimental method followed the requirements of section 2.3.3, "Skin Irritation Test," in the Ministry of Health's "Disinfection Technical Specifications (2002 Edition)," conducting multiple complete skin irritation tests. The final results are shown in Table 5.

[0063] Table 5

[0064] Skin irritation Number of days when the stimulus occurs Example 1 Non-irritating - Example 2 Non-irritating - Example 3 Non-irritating - Example 4 Non-irritating - Comparative Example 1 moderate stimulation 13d Comparative Example 2 Mild stimulation 10d Comparative Example 3 moderate stimulation 12d

[0065] As shown in Table 5, Examples 1-4 exhibited good skin gentleness, and repeated application during the observation period did not show any skin irritation to rabbits. However, Comparative Examples 1-3, which replaced glycolipid surfactants with common polyhydroxy moisturizers and conventional nonionic surfactants respectively, did not show any neutralizing effect on the irritation of quaternary ammonium salts, and the prepared quaternary ammonium salt disinfectant gels exhibited significant skin irritation. The comparison reveals that glycolipid surfactants, compared to chemically similar polyhydroxy moisturizers and conventional nonionic surfactants, uniquely enhance the skin gentleness of quaternary ammonium salt disinfectants and reduce skin irritation.

Claims

1. A quaternary ammonium salt leave-on disinfectant gel having skin mildness, characterized in that, The raw materials and their weight proportions for the quaternary ammonium salt hand sanitizer gel are as follows: 0.1-0.5 parts of quaternary ammonium salt Glycolipid surfactants: 0.02-0.3 parts 0.5-1 part gel matrix pH adjuster 0.1-0.5 parts 97-99.3 parts deionized water; The glycolipid surfactant is one or more of rhamnolipin, sophorolipid, and trehalolipid; The gel matrix is ​​one or more of methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, and hydroxypropylcellulose. The quaternary ammonium salt is one or a mixture of two types of single-chain quaternary ammonium salt and double-chain quaternary ammonium salt; The single-chain quaternary ammonium salt is one or more of benzalkonium chloride, benzalkonium bromide, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, dodecyl-dimethyl-2-phenoxyethylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, and tetradecyldimethylbenzylammonium bromide; the double-chain quaternary ammonium salt is one or more of bis(octyl)dimethylammonium chloride, bis(octyl)dimethylammonium bromide, bis(decyl)dimethylammonium chloride, bis(decyl)dimethylammonium bromide, bis(dodecyl)dimethylammonium bromide, bis(dodecyl)dimethylammonium chloride, bis(tetradecyl)dimethylammonium chloride, and bis(tetradecyl)dimethylammonium bromide. The pH adjuster is one or more of triethanolamine, monoethanolamine, ethylenediamine, and arginine.

2. The quaternary ammonium salt hand sanitizer gel according to claim 1, characterized in that, The raw materials and their weight proportions for the quaternary ammonium salt hand sanitizer gel are as follows: 0.15 parts of quaternary ammonium salt 0.3 parts glycolipid surfactant 0.7 parts gel matrix pH adjuster 0.3 parts 98.55 parts of deionized water.

3. A method for preparing a skin-mild quaternary ammonium salt no-rinse disinfectant gel as described in claim 1, characterized in that, The preparation method is as follows: (1) Take 0.1-0.5 parts of quaternary ammonium salt and mix it thoroughly with 0.02-0.3 parts of glycolipid surfactant until the mixture is homogeneous; (2) Add 80 parts of deionized water to the product obtained in step (1) while stirring to fully dissolve each component until the solution is homogeneous, clear and free of insoluble matter. (3) Heat the product obtained in step (2) to above 50°C, maintain the temperature and add 0.5-1 part of gel matrix, gradually cool down to room temperature while stirring, and maintain the stirring speed at 120 rpm until gel is formed; (4) Add 0.1-0.5 parts of pH adjuster to adjust the pH of the solution to 4-7 to the product obtained in step (3), and add deionized water to make the mass of the system reach 100 parts. Continue stirring until the system is transparent and uniform to obtain the quaternary ammonium salt no-wash disinfectant gel.

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