Anti-mosquito cream and preparation method thereof

Abstract

The invention relates to anti-mosquito cream and a preparation method thereof.The anti-mosquito cream comprises a lipophilic emulsified mixture A-phase mixture, a hydrophilic mixture B-phase mixture and a thickening mixture C. The A-phase mixture comprises, by weight, 18-20 parts of stearic acid, 10-32 parts of liquid paraffin, 3 parts of glycerin monostearate and 10 parts of polyethylene glycol monostearate; the B-phase mixture comprises the following components in parts by weight: 6-20 parts of glycerol, 0.2 part of Kathon CG and 89-93 parts of distilled water; and the C-phase mixture is prepared from 6.7 to 10 parts of cross-linked polyvinylpyrrolidone and 20 to 40 parts of DEETs (Diethylene Terephthalate).

Description

Technical Field

[0001] The invention relates to the technical field of daily chemical products, in particular to a mosquito repellent cream and a preparation method thereof. Background Art

[0002] Mosquito repellent cream is a daily product with mosquito repellent added. It is used in hot summer when there are many mosquitoes. When using it, apply the mosquito repellent cream on the exposed skin where mosquitoes need to be avoided to effectively avoid mosquitoes and avoid mosquito bites, thereby preventing itching, rash-like skin diseases caused by mosquito bites and the spread of infectious diseases such as dengue fever and malaria. The mosquito repellent principle of this type of product is to slowly release the active mosquito repellent ingredient DEET (DEET is abbreviated as DEET) sealed in the cream. The actual effective repellent time of most existing mosquito repellent creams is generally about 4 hours.

[0003] The mosquito repellent creams on the market have been improved and upgraded in terms of skin feel and state, but the effective mosquito repellent duration and mosquito repellent rate are still not ideal, with defects such as short actual mosquito repellent time, low mosquito repellent rate, and poor waterproof effect. In order to extend the duration of action of mosquito repellent products, the main method currently used is to release drugs slowly through encapsulation technology, thereby extending the drug release time. A common method is to encapsulate DEET in microcapsules. Although this type of technology can increase the mosquito repellent time of DEET, the preparation technology is difficult and the preparation cost is high, and the actual mosquito repellent duration is still not ideal.

[0004] For example, the American Sawyer mosquito repellent cream uses submicron encapsulation technology to encapsulate DEET in a protein, which slowly dissolves and releases DEET to extend the mosquito repellent time. However, in order to achieve a better mosquito repellent effect, the DEET content is as high as 20%, and its biological safety is questionable. Moreover, its actual mosquito repellent time is not ideal, especially when used outdoors, the mosquito repellent time is greatly reduced, resulting in its practicality in urgent need of improvement. Summary of the invention

[0005] Based on this, it is necessary to provide a mosquito repellent cream and a preparation method thereof that can solve the problems of short real mosquito repellent time and low mosquito repellent rate.

[0006] In one aspect, an embodiment of the present invention provides a mosquito repellent cream, comprising a lipophilic emulsified mixture phase A mixture, a hydrophilic mixture phase B mixture and a thickening mixture phase C mixture, in parts by weight:

[0007] Phase A mixture includes 18-20 parts of stearic acid, 10-32 parts of liquid paraffin, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate;

[0008] Phase B mixture includes 6-20 parts of glycerin, 0.2 parts of Kaisong CG, and 89-93 parts of distilled water;

[0009] The phase C mixture includes 6.7-10 parts of cross-linked polyvinyl pyrrolidone and 20-40 parts of DEET.

[0010] Preferably, the hydrophilic mixture B phase mixture further comprises 0.2 parts of xanthan gum.

[0011] Preferably, the lipophilic emulsified mixture phase A mixture further comprises 10 parts of white vaseline, 4 parts of cetearyl alcohol and 8 parts of cetyl alcohol.

[0012] Preferably, the lipophilic emulsified mixture phase A mixture further comprises 4 parts of cetearyl alcohol and 4 parts of hexadecyl alcohol.

[0013] Preferably, the lipophilic emulsified mixture phase A mixture further comprises 5 parts of cetearyl alcohol and 4 parts of hexadecyl alcohol.

[0014] On the other hand, a method for preparing a mosquito repellent cream is provided, comprising the following steps:

[0015] S1. Weigh the materials according to the formula, and then mix them into a phase A mixture, a phase B mixture and a phase C mixture respectively;

[0016] Heat the phase A mixture to 85°C and set aside;

[0017] After heating the phase B mixture to 90°C, perform air drying for 3 minutes, and immediately perform rapid cooling after air drying for standby use;

[0018] S2, pouring the phase B mixture treated in step S1 into the phase A mixture treated, homogenizing with a high-speed homogenizer for 5 minutes, rapidly cooling in an ice bath, and standing for 15 minutes to obtain an emulsion;

[0019] S3, after heating the emulsion to 45°C, add the C phase mixture, and stir with a homogenizer for 30 minutes until uniform, and introduce nitrogen gas during the stirring process;

[0020] S4. After cooling the mixture to 35° C., stirring was stopped. Within a time window of 3 minutes after stirring was stopped, the mixture was rapidly cooled to obtain a finished product.

[0021] Preferably, in step S1, the temperature of the rapid cooling treatment is -15°C, and the time of the rapid cooling treatment is 30 minutes.

[0022] Preferably, in step S2, the time for the rapid cooling treatment in an ice bath is 30 min.

[0023] Preferably, in step S5, the specific method for rapidly cooling the mixture is: within a time window of 3 minutes after stopping stirring, rapidly cooling the mixture at -15°C for 2 hours.

[0024] Beneficial effects: The present invention adopts a new formula of slow-release polymer cross-linked polyvinyl pyrrolidone to prepare a mosquito repellent slow-release cream, which realizes the efficient adsorption of DEET by polymer cross-linked polyvinyl pyrrolidone, thereby effectively prolonging the release of the active ingredient DEET, ensuring the effective mosquito repellent duration of the product, and also having good mosquito repellent efficiency and effect. The improvement of the formula enhances the retention of DEET in the cream, reduces the irritation of DEET to the skin, makes the product's properties and skin feel better, and has good water solubility, delicate skin feel, easy to spread, comfortable and non-greasy, easy to clean, and more conducive to use on the skin surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other purposes, features and advantages of the present invention will become more clear by more specific description of the preferred embodiments of the present invention shown in the accompanying drawings. The same reference numerals indicate the same parts in all the accompanying drawings, and the accompanying drawings are not deliberately scaled to the actual size, and the focus is on illustrating the main purpose of the present invention.

[0026] Figure 1 It is a standard curve diagram of DEET concentration and peak area in the standard solution of the present invention;

[0027] Figure 2 The corresponding relationship curves of XDC indoor release time and peak area and release time and residual amount;

[0028] Figure 3 This is a time-concentration comparison chart of XDC and China Asia America;

[0029] Figure 4 The corresponding relationship curves of VDC indoor release time and peak area and release time and residual amount;

[0030] Figure 5 It is a time-concentration comparison chart of VDC and US OFF;

[0031] Figure 6 The corresponding relationship curves of DDC indoor release time and peak area and release time and residual amount;

[0032] Figure 7 It is a time-concentration comparison chart of DDC and US OFF;

[0033] Figure 8 The corresponding relationship curves of CDC indoor release time and peak area and release time and residual amount;

[0034] Fig. 9 This is a time-concentration comparison chart of CDC and American Sawyer;

[0035] Fig.10 The corresponding relationship curves of XDC outdoor release time and peak area and release time and residual amount;

[0036] Fig.11 The corresponding relationship curves of VDC outdoor release time and peak area and release time and residual amount;

[0037] Fig.12 The corresponding relationship curves of DDC outdoor release time and peak area and release time and residual amount;

[0038] Fig.13 The corresponding relationship curves of CDC outdoor release time and peak area, and release time and residual amount;

[0039] Fig.14 It is the prediction map of mosquito repellent time concentration for XDC and US OFF;

[0040] Fig.15 It is the prediction map of time concentration of mosquito repellent for VDC and US OFF;

[0041] Fig.16 It is the prediction map of time concentration of mosquito repellent for DDC and US OFF;

[0042] Fig.17 This is the time concentration prediction chart of CDC, American sawyer and Chinese cloth bite mosquito repellent. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0044] like Figure 1-17 As shown, a mosquito repellent cream includes a lipophilic emulsified mixture phase A mixture, a hydrophilic mixture phase B mixture and a thickening mixture phase C mixture. By weight, the phase A mixture includes 18-20 parts of stearic acid, 10-32 parts of liquid paraffin, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate; the phase B mixture includes 6-20 parts of glycerol, 0.2 parts of Kaisong CG, and 89-93 parts of distilled water; the phase C mixture includes 6.7-10 parts of cross-linked polyvinyl pyrrolidone and 20-40 parts of DEET. Among them, the phase A is mainly a lipophilic emulsifying or dispersing component; the phase B is mainly a hydrophilic phase component; and the phase C is a component for enhancing molecular retention and thickening.

[0045] The active ingredient DEET in mosquito repellent cream plays a role in repelling mosquitoes. When the mosquito repellent cream containing the effective mosquito repellent ingredient DEET is applied to the skin, the DEET in the mosquito repellent cream is gradually released slowly over time and forms a volatile isolation layer with a certain DEET concentration on the skin surface. The long-term release and concentration maintenance of DEET are the key to maintaining the mosquito repellent effect.

[0046] The proportion of polyethylene glycol monostearate, Kaisong CG, and cross-linked polyvinyl pyrrolidone in the formula of the present invention changes with the concentration of DEET, thereby enhancing the adhesion of polyethylene glycol monostearate to the active ingredient DEET and ensuring the retention time of the active ingredient DEET on the skin. The present invention improves the mosquito repelling effect and mosquito repelling time of the mosquito repellent cream, greatly prolongs the real and effective mosquito repelling time outdoors, reduces the amount of the active ingredient DEET, can achieve a better mosquito repelling effect, and also enhances its biological safety.

[0047] In a preferred embodiment, the hydrophilic mixture phase B also includes 0.2 parts of xanthan gum. For tender or sensitive skin, xanthan gum is added to the hydrophilic mixture phase B to obtain a mosquito repellent cream product XDC specifically for tender or sensitive skin. XDC optimizes the skin softening ingredients such as stearic acid, liquid paraffin, and xanthan gum, so that it can form a soft and smooth protective barrier on the skin surface and enhance the moisturizing and smooth feeling at the same time; through the dual optimization of the moisturizing barrier and high retention, this product is both skin-friendly and enhances the duration of mosquito repelling, and is suitable for people with tender or sensitive skin to use for long-term mosquito repellent. The formula of XDC is characterized by long-lasting retention of active ingredients and skin-friendly hydration. Among the ingredients of XDC, polyethylene glycol monostearate plays the role of emulsification and thickening, stabilization and softening; cross-linked polyvinyl pyrrolidone plays the role of increasing consistency and adhesion; stearic acid plays the role of moisturizing and emollient; liquid paraffin plays the role of increasing moisture and smoothness, and has good oil solubility; xanthan gum plays the role of hydrophilic surfactant and antioxidant; Kaisong CG plays the role of regulating acidity and antioxidant.

[0048] In a preferred embodiment, the lipophilic emulsified mixture phase A also includes 10 parts of white vaseline, 4 parts of cetearyl alcohol, and 8 parts of hexadecyl alcohol. For dry skin, white vaseline, cetearyl alcohol, and hexadecyl alcohol are added to the phase A mixture to obtain a mosquito repellent cream product VDC.

[0049] In a preferred embodiment, the lipophilic emulsified mixture phase A also includes 4 parts of cetearyl alcohol and 4 parts of hexadecyl alcohol. For dry skin, cetearyl alcohol and hexadecyl alcohol are added to the phase A mixture to obtain a mosquito repellent cream product DDC.

[0050] The patented products VDC and DDC optimize the oily ingredients such as stearic acid, liquid paraffin, white petrolatum, cetearyl alcohol, hexadecanol, glyceryl monostearate, etc., so that the products can form an oily supramolecular film, which not only moisturizes the skin, but also maintains a high molecular retention efficiency with the active ingredients. Therefore, it can be used as a long-term mosquito repellent for people with dry skin. In the VDC and DDC formulas, polyethylene glycol monostearate plays the role of dispersion, emulsification, solubilization, moisturization, and softening; Kaisong CG plays the role of regulating acidity and anti-oxidation; cross-linked polyvinyl pyrrolidone plays the role of increasing viscosity and adhesion; stearic acid plays the role of moisturizing and moisturizing; liquid paraffin plays the role of increasing moisturizing and smoothness, and has good oil solubility; white petrolatum provides a protective barrier for the skin, moisturizing and non-irritating; cetearyl alcohol increases the moisture content of the skin, forms a moisturizing film, and prevents water loss; hexadecanol plays the role of emulsification, lubrication, dispersion, and defoaming; glyceryl monostearate plays the role of emulsification, dispersion, and defoaming.

[0051] In a preferred embodiment, the lipophilic emulsified mixture A phase mixture also includes 5 parts of cetearyl alcohol and 4 parts of hexadecanol. For oily skin, cetearyl alcohol and hexadecanol are added to the A phase mixture to obtain the final mosquito repellent cream product CDC. The product CDC of this patent removes the oily components and optimizes the proportion of the remaining components, so that the product can maintain the efficient retention of active ingredients on the basis of delicate lubrication, and is suitable for people with oily skin to use long-term mosquito repellent. In the CDC formula, polyethylene glycol monostearate has the functions of dispersion, emulsification, solubilization, wetting, and softening; cross-linked polyvinyl pyrrolidone increases viscosity and adhesion; stearic acid can moisturize and moisturize the skin; liquid paraffin increases moisturizing and smoothness, and has good oil solubility; cetearyl alcohol plays the role of increasing skin moisture, forming a moisturizing film, and preventing water loss; hexadecanol plays the role of emulsification, lubrication, dispersion, and defoaming; monostearate glyceryl plays the role of emulsification, dispersion, and defoaming; Kaisong CG adjusts acidity and protects the skin from oxidation.

[0052] A method for preparing a mosquito repellent cream comprises the following steps:

[0053] S1. According to the above formula, the materials are weighed respectively, and then mixed into a phase A mixture, a phase B mixture and a phase C mixture respectively; the phase A mixture is heated to 85° C. and set aside; the phase B mixture is heated to 90° C. and then subjected to a blast drying treatment for 3 minutes. After the blast drying treatment, it is immediately subjected to a rapid cooling treatment and set aside; so as to reduce the instability of the emulsion and reduce the stratification ratio at the same time;

[0054] S2, pouring the phase B mixture treated in step S1 into the phase A mixture treated, homogenizing for 5 minutes using a high-speed homogenizer, and then rapidly cooling in an ice bath, and standing for 15 minutes after rapid cooling to obtain an emulsion, so as to keep the equilibrium state of the system less damaged;

[0055] S3, after heating the emulsion to 45°C, add the C phase mixture, and stir with a homogenizer for 30 minutes until uniform, and introduce nitrogen gas during the stirring process;

[0056] S4, cooling the mixture to 35°C and stopping stirring, and rapidly cooling the mixture within a 3-minute time window after stopping stirring to obtain a finished product. Thus, a steady-state product is obtained;

[0057] In a preferred embodiment, in step S1, the temperature of the rapid cooling treatment is -15°C, and the time of the rapid cooling treatment is 30 minutes.

[0058] In a preferred embodiment, in step S2, the time for the rapid cooling treatment in an ice bath is 30 minutes.

[0059] In a preferred embodiment, in step S5, the specific method of rapidly cooling the mixture is: within a time window of 3 minutes after stopping stirring, rapidly cooling the mixture at -15°C for 2 hours.

[0060] The present invention adopts a new formula of slow-release polymer cross-linked polyvinyl pyrrolidone to prepare four types of mosquito repellent slow-release creams, realizes efficient adsorption of DEET by polymer cross-linked polyvinyl pyrrolidone, thereby effectively prolonging the release of active ingredient DEET, ensuring the effective mosquito repellent duration of the product, and also having good mosquito repellent efficiency and effect. The present invention enhances the retention of DEET by the cream, reduces the stimulation of DEET to the skin, makes the product's properties and skin feel better, and has good water solubility, delicate skin feel, easy to spread, comfortable and non-greasy, easy to clean, and more conducive to use on the skin surface.

[0061] In order to have a further understanding and recognition of the technical solution of the present invention, several embodiments are listed to further illustrate it in detail.

[0062] Example 1

[0063] A formula of a mosquito repellent cream comprises a phase A mixture, a phase B mixture and a phase C mixture. In parts by weight, the phase A mixture comprises 18 parts of stearic acid, 32 parts of liquid paraffin, 3 parts of glyceryl monostearate and 10 parts of polyethylene glycol monostearate; the phase B mixture comprises 20 parts of glycerol, 0.2 parts of Kesong CG, 90 parts of distilled water and 0.2 parts of xanthan gum; and the phase C mixture comprises 6.7 parts of cross-linked polyvinyl pyrrolidone and 20 parts of DEET.

[0064] The preparation method comprises the following steps: S1, weighing materials according to the formula, and then mixing them into a phase A mixture, a phase B mixture and a phase C mixture respectively; heating the phase A mixture to 85°C for standby use; heating the phase B mixture to 90°C, performing a blast drying treatment for 3 minutes, and immediately performing a rapid cooling treatment after the blast drying treatment for standby use; S2, pouring the phase B mixture treated in step S1 into the phase A mixture treated, performing a homogenizing treatment for 5 minutes using a high-speed homogenizer, performing a rapid cooling treatment in an ice bath, and standing for 15 minutes to obtain an emulsion; S3, heating the emulsion to 45°C, adding the phase C mixture, and stirring the mixture for 30 minutes using a homogenizer until it is uniform, and introducing nitrogen gas during the stirring process; S4, stopping stirring after cooling the mixture to 35°C, and rapidly cooling the mixture within a time window of 3 minutes after stopping stirring, to prepare a mosquito repellent cream finished product XDC.

[0065] Example 2

[0066] A mosquito repellent cream comprises a phase A mixture, a phase B mixture and a phase C mixture, wherein the phase A mixture comprises 20 parts of stearic acid, 10 parts of liquid paraffin, 10 parts of white vaseline, 4 parts of cetearyl alcohol, 8 parts of hexadecanol, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate by weight; the phase B mixture comprises 6 parts of glycerol, 89 parts of distilled water, and 0.2 parts of Kayson CG; and the phase C mixture comprises 10 parts of cross-linked polyvinyl pyrrolidone and 30 parts of DEET. The preparation method is the same as that in Example 1, and a mosquito repellent cream finished product VDC is obtained.

[0067] Example 3

[0068] A mosquito repellent cream comprises a phase A mixture, a phase B mixture and a phase C mixture, wherein the phase A mixture comprises 20 parts of stearic acid, 10 parts of liquid paraffin, 10 parts of white vaseline, 4 parts of cetearyl alcohol, 8 parts of hexadecanol, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate by weight; the phase B mixture comprises 6 parts of glycerol, 93 parts of distilled water, and 0.2 parts of Kaisong CG; and the phase C mixture comprises 10 parts of cross-linked polyvinyl pyrrolidone and 30 parts of DEET. The preparation method is the same as that in Example 1, and a mosquito repellent cream finished product DDC is obtained.

[0069] Example 4

[0070] A mosquito repellent cream comprises a phase A mixture, a phase B mixture and a phase C mixture, wherein the phase A mixture comprises 20 parts of stearic acid, 10 parts of liquid paraffin, 5 parts of cetearyl alcohol, 4 parts of hexadecanol, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate by weight; the phase B mixture comprises 6 parts of glycerol, 92 parts of distilled water, and 0.2 parts of Kaisong CG; and the phase C mixture comprises 10 parts of cross-linked polyvinyl pyrrolidone and 40 parts of DEET. The preparation method is the same as that in Example 1, and a mosquito repellent cream finished product CDC is obtained.

[0071] Comparative Example 1

[0072] A commercially available mosquito repellent from China Yamei with a DEET concentration of 10%.

[0073] Comparative Example 2

[0074] A commercially available mosquito repellent from Johnson & Johnson, USA, has a DEET concentration of 15%.

[0075] Comparative Example 3

[0076] A commercially available mosquito repellent from the United States with a DEET concentration of 20%.

[0077] Comparative Example 4

[0078] Commercially available mosquito repellent Chinese cloth bites with a DEET concentration of 20%.

[0079] The preparation methods of Examples 1-4 are the same, and mosquito repellent cream XDC with a DEET concentration of 10%, mosquito repellent cream VDC with a DEET concentration of 15%, mosquito repellent cream DDC with a DEET concentration of 15%, and mosquito repellent cream CDC with a DEET concentration of 20% are prepared respectively. The mosquito repellent cream formulas of Examples 1-4 are shown in Table 1 in terms of weight proportions:

[0080] Table 1

[0081]

[0082]

[0083] The concentrations of the active ingredient DEET in Examples 1-4 and Comparative Examples 1-4 are shown in Table 2:

[0084] Table 2

[0085]

[0086] The products XDC, VDC, DDC, and CDC prepared in Examples 1-4 were respectively subjected to a DEET sustained-release test together with the commercial products of Comparative Examples 1-3. The products XDC, VDC, DDC, and CDC prepared in Examples 1-4 were respectively subjected to a live mosquito repellent experiment together with the commercial products of Comparative Examples 1-4.

[0087] 1. Experiment on sustained release of DEET using liquid chromatography-mass spectrometry

[0088] 1. Set up LC-MS test conditions: Liquid chromatography-mass spectrometry Thermo Fisher Scientific C 18(250mm×5.6mm,5μm); mobile phase is methanol:water (90:10); flow rate is 0.5ml / min; detection wavelength is 254nm; column temperature is 30℃.

[0089] 2. Prepare the standard solution of DEET and measure the standard curve:

[0090] Accurately weigh 0.01g DEET reference substance into a 25ml beaker, wash the beaker wall several times with isopropanol and transfer to a 10ml volumetric flask, shake to volume, and ultrasonicate for 1min to obtain a reference substance solution with a concentration of 1mg / ml. Then use a pipette to measure 50μl, 100μl, 200μl, 300μl, and 400μl into a 10ml volumetric flask, shake to volume with isopropanol to prepare 0.005mg / ml, 0.01mg / ml, 0.02mg / ml, 0.03mg / ml, and 0.04mg / ml standard solutions. Measure (1.5±0.2)ml with a syringe, sieve, and measure LC-MS. The standard curve of DEET concentration and peak area in the standard solution is as follows Figure 1 shown.

[0091] 3. Determination of DEET residues in samples from different environments:

[0092] 0.01 g of each sample of Examples 1-4 and Comparative Examples 1-3 was taken with a disposable glove, and the sample was evenly smeared on the inner wall of a 25 ml beaker to simulate the process of applying the cream on the human body. The mass was ensured to remain unchanged during the smearing process. Ten beakers with the same amount of sample were set for each sample of Examples 1-4 and Comparative Examples 1-3;

[0093] ① Experiment on determination of DEET residue at different times indoors (oven conditions):

[0094] Take out 5 of the 10 beakers of each sample, place the beakers open in a 32°C oven (simulating a human body surface temperature of 32°C), take out a beaker for each sample at 1h, 3h, 5h, 7h, and 10h, dissolve the sample in the beaker with isopropanol, wash it several times and transfer it to a 10ml volumetric flask, shake it to volume, and obtain a solution with a concentration of 0.1mg / ml. Then use a pipette to take 1ml each into a 10ml volumetric flask, shake it to volume again with isopropanol, and obtain a sample solution with a mosquito repellent cream concentration of 0.01mg / ml. After passing through a 0.45μm microporous filter membrane, use a liquid chromatography-mass spectrometry to determine the residual amount of DEET in the mosquito repellent cream sample solution.

[0095] ② Experiment on determination of DEET residues at different times in sunny outdoor with level 3 wind:

[0096] Take out the remaining 5 beakers of each sample, place the beakers open in a sunny outdoor environment (temperature: 28-35°C, wind speed: level 3 wind), take a beaker with a sample at 1h, 3h, 5h, 7h, and 10h for each sample, dissolve the remaining sample in the beaker with isopropanol, wash it several times and transfer it to a 10ml volumetric flask, shake it to the same volume, and obtain a solution with a concentration of 0.1mg / ml. Then use a pipette to take 1ml each into a 10ml volumetric flask, shake it to the same volume again with isopropanol, and obtain a sample solution with a mosquito repellent cream concentration of 0.01mg / ml. Pass through a 0.45μm microporous filter membrane, and use a liquid chromatography-mass spectrometer to determine the residual amount of DEET in the mosquito repellent cream of the sample solution.

[0097] 4. LC-MS test results:

[0098] (1) Results of comparative tests of Example 1 (XDC) and Comparative Example 1 with an initial concentration of 10% DEET

[0099] The corresponding values ​​of time, peak area and residual DEET concentration of Example 1 at 10% concentration in indoor environment and outdoor environment are shown in Table 3 below:

[0100] Table 3

[0101]

[0102]

[0103] ①Indoors (oven conditions), Figure 2 The graphs are the corresponding relationship between the indoor release time and the peak area of ​​XDC and the release time and the residual amount; combined with Table 3, it can be seen that after 10 hours, the retention amount of DEET in the sample of Example 1 is 65%, indicating that the mosquito repellent cream XDC still has the mosquito repellent effect after 10 hours.

[0104] Figure 3 It is the time-concentration comparison diagram of XDC and China Asia America after different time;

[0105] It can be seen that at the same initial concentration, the net DEET content of mosquito repellent cream XDC is 6.37% after 10 hours, while the net DEET content of China Yamei after 10 hours is 3.08%. After 10 hours, the DEET content of mosquito repellent cream XDC is 3.29% higher than that of China Yamei. The concentration of China Yamei decreases quickly, and it is impossible to achieve a longer effective mosquito repellent time.

[0106] ②In outdoor environment, Fig.10 The corresponding relationship curves of XDC outdoor release time and peak area, and release time and residual amount; combined with Table 3, it can be seen that the retention amount of DEET after 10 hours is 50%, indicating that the mosquito repellent cream XDC still has a mosquito repellent effect after 10 hours.

[0107] (2) Results of comparative tests of Example 2 (VDC) with an initial DEET concentration of 15% and Comparative Example 2

[0108] The corresponding values ​​of time, peak area and residual DEET concentration of Example 2 with a concentration of 15% in indoor and outdoor environments are shown in Table 4 below:

[0109] Table 4

[0110]

[0111]

[0112] ①Indoors (oven conditions), Figure 4 The corresponding relationship curves of VDC indoor release time and peak area, and release time and residual amount; combined with Table 4, it can be seen that the retention amount of DEET after 10 hours is 55%, indicating that the mosquito repellent cream VDC still has a mosquito repellent effect after 10 hours.

[0113] Figure 5 The time-concentration comparison chart of VDC and US OFF after different time periods; at the same concentration, the net DEET content of VDC mosquito repellent cream after 10 hours is 8.32%; the net DEET content of US Johnson's OFF after 10 hours is 6.52%. After 10 hours, the DEET content of VDC mosquito repellent cream is 1.8% higher than that of US OFF.

[0114] ②In outdoor environment, Fig.11 The curves are the corresponding relationship between the outdoor release time and peak area of ​​VDC and the release time and residual amount. The retention amount of DEET after 10 hours is 54%, indicating that the mosquito repellent cream VDC still has the mosquito repellent effect after 10 hours.

[0115] (3) Results of comparative tests of Example 3 (DDC) and Comparative Example 2 with an initial concentration of 15% DEET

[0116] The corresponding values ​​of time, peak area and residual DEET concentration of Example 3 with a concentration of 15% in indoor and outdoor environments are shown in Table 5 below:

[0117] Table 5

[0118]

[0119] ①Indoors (oven conditions), Figure 6 The corresponding relationship curves of DDC indoor release time and peak area, and release time and residual amount; combined with Table 5, it can be seen that the retention amount of DEET after 10 hours is 55%, indicating that the mosquito repellent cream DDC still has a mosquito repellent effect after 10 hours.

[0120] Figure 7This is a time-concentration comparison chart of DDC and US OFF. At the same concentration, the net DEET content of mosquito repellent cream DDC is 8.54% after 10 hours, while the net DEET content of US OFF is 6.52% after 10 hours. After 10 hours, the DEET content of mosquito repellent cream DDC is 2.02% higher than that of US OFF.

[0121] ②In outdoor environment, Fig.12 The curves are the corresponding relationship between the outdoor release time and peak area of ​​DDC and the release time and residual amount. The retention amount of DEET after 10 hours is 50%, indicating that the mosquito repellent cream DDC still has the mosquito repellent effect after 10 hours.

[0122] (4) Results of comparative tests of DEET initial 20% concentration Example 4 (CDC) and Comparative Example 3

[0123] The corresponding values ​​of time, peak area and residual DEET concentration of Example 4 at 15% concentration in indoor and outdoor environments are shown in Table 6 below:

[0124] Table 6

[0125]

[0126] ①Indoors (oven conditions), Figure 8 The corresponding relationship curves of CDC indoor release time and peak area, and release time and residual amount; combined with Table 6, it can be seen that the retention amount of DEET after 10 hours is 75%, indicating that the mosquito repellent cream CDC still has a mosquito repellent effect after 10 hours.

[0127] Fig. 9 This is a time-concentration comparison chart of CDC and American sawyer. At the same concentration, the net DEET content of CDC mosquito repellent cream after 10 hours is 14.9%; the net DEET content of American sawyer after 10 hours is 12.8%. After 10 hours, the DEET content of CDC mosquito repellent cream is 2.1% higher than that of American sawyer.

[0128] ②In outdoor environment, Fig.13 The curves are the corresponding relationship between the outdoor release time and peak area of ​​CDC and the release time and residual amount. The retention amount of DEET after 10 hours is 61%, indicating that the mosquito repellent cream CDC still has the mosquito repellent effect after 10 hours.

[0129] Conclusion: In summary, in both indoor and outdoor environments, the sustained-release duration of the active ingredient of the products of Examples 1-4 prepared according to the formulation and preparation method of the present invention is greater than the sustained-release duration of the active ingredient of Comparative Examples 1-3 of the same concentration.

[0130] 2. Live Mosquito Avoidance Experiment

[0131] According to the requirements of Part 9 of GB / T 13917.9-2009, a live mosquito avoidance experiment was conducted to evaluate the mosquito repellent efficacy.

[0132] 1. Experimental subjects

[0133] Testers: Adults aged 20-40;

[0134] Aedes albopictus: 100 female mosquitoes that were hatched in the laboratory and are 3 to 5 days old and have not fed blood.

[0135] 2. Evaluation of mosquito attack power: 100 Aedes albopictus are placed in a mosquito cage (40cm long, 30cm wide, 30cm high). The tester's back of hand is exposed to 4cm*4cm of skin, and the rest of the hand is tightly covered. Put your hand into the mosquito cage and stay there for 2 minutes. Observe carefully. If you find mosquitoes landing, shake them away before biting, it is counted as one test insect landing. If more than 10 test insects land on the tester and the test insects, the attack power is qualified. People with qualified attack power and the mosquitoes in this cage can be used in mosquito repellent experiments.

[0136] 3. Experimental conditions of the repellent experiment: the temperature is maintained at 26℃~30℃, and the relative humidity is maintained at 65%±10%.

[0137] Experimental repellent: products of Examples 1-4 and samples of Comparative Examples 1-3 at the same concentration;

[0138] 4. Mosquito repellent test: Select 4 testers who have passed the attack test, draw an area of ​​5*5cm on the back of each of their hands, and apply the repellent to be tested (the application amount is 1.5mg / cm 2 ), expose 4cm*4cm of the skin, and strictly protect the rest of the hand. The other hand is a blank control. 1 hour after applying the repellent, put your hand into the mosquito cage for 2 minutes to observe whether there are mosquitoes coming to land and suck blood. After that, test once every 1 hour. As long as there is a mosquito sucking blood, the repellent is considered ineffective. Record the effective protection time (h) of the repellent. A blank control test should be performed first at each time point to ensure the accuracy of the experimental results. Test insects with qualified attack power can continue the experiment, and those that fail need to be replaced.

[0139] 5. Experimental results

[0140] (1) The mosquito repelling effects of XDC, the product of Example 1, at a concentration of 10%, and Chinese Yamei at the same concentration are shown in Table 7 below:

[0141] Table 7

[0142] time China Yamei mosquito repellent effect XDC mosquito repellent effect Within 2 hours Mosquitoes are 0.5 cm away from the skin Mosquitoes are 0.5 cm away from the skin 2-3h Mosquitoes are 0.1cm away from the skin Mosquitoes are 0.5 cm away from the skin 3-4h Mosquitoes stay for 1 second and fly away Mosquitoes are 0.1cm away from the skin 4-5h Mosquitoes stay for 1 second and fly away Mosquitoes stay for 1 second and fly away 5-6h Mosquitoes start biting Mosquitoes stay for 1 second and fly away 6.1h later Mosquitoes start biting

[0143] According to the above experimental data, the XDC and the time concentration prediction of Chinese Asian mosquito repellent were obtained. Fig.14 .

[0144] It can be seen that the mosquito repellent cream product XDC of Example 1 has an effective mosquito repelling time of 6.1 hours, which is at least 1 hour longer than the mosquito repellent cream of Comparative Example 1 (China Yamei) with the same DEET concentration on the market.

[0145] (2) The mosquito repellent effects of the product VDC of Example 2 at a concentration of 15% and the American Johnson's OFF at the same concentration are shown in Table 8 below:

[0146] Table 8

[0147] time The mosquito repellent effect of Johnson & Johnson OFF VDC mosquito repellent effect Within 1 hour Mosquitoes are 0.5 cm away from the skin The mosquito is 1-2cm away from the skin 1-2h Mosquitoes are 0.1cm away from the skin The mosquito is 1-2cm away from the skin 2-3h Mosquitoes stay for 1 second and fly away Mosquitoes are 0.5 cm away from the skin 4.5-5h Mosquitoes start biting Mosquitoes are 0.1cm away from the skin 5-6h - Mosquitoes stay for 1 second and fly away 6.7 hours later - Mosquitoes start biting

[0148] Based on the experimental data, the VDC and the US OFF mosquito repellent time concentration prediction were obtained. Fig.15 .

[0149] It can be seen that the mosquito repellent cream product VDC of Example 2 has an effective mosquito repelling time of 6.7 hours, which is at least 2 hours longer than the mosquito repellent cream of Comparative Example 2 (American Johnson) with the same DEET concentration.

[0150] (3) The mosquito repellent effects of DDC, the product of Example 3, with a concentration of 15%, and SC Johnson OFF with the same DEET concentration are shown in Table 9 below:

[0151] Table 9

[0152] time The mosquito repellent effect of Johnson & Johnson OFF DDC mosquito repellent effect Within 1 hour Mosquitoes are 0.5 cm away from the skin The mosquito is 1-2cm away from the skin 1-2h Mosquitoes are 0.1cm away from the skin The mosquito is 1-2cm away from the skin 2-4h Mosquitoes stay for 1 second and fly away Mosquitoes are 0.5 cm away from the skin 4.5-5h Mosquitoes start biting Mosquitoes are 0.1cm away from the skin 5-6h - Mosquitoes stay for 1 second and fly away 7h later - Mosquitoes start biting

[0153] Based on the experimental data, the DDC and US OFF mosquito repellent time concentration predictions were obtained. Fig.16 .

[0154] It can be seen that the mosquito repellent cream product DDC of Example 3 has an effective mosquito repellent time of 7 hours, which is at least 2 hours longer than the mosquito repellent cream (American Johnson) of Comparative Example 2 with the same concentration.

[0155] (4) The mosquito repelling effects of CDC, the product of Example 4, with a concentration of 20%, and the American Sawyer and Chinese cloth bite with the same DEET concentration are shown in Table 10 below:

[0156] Table 10

[0157] time Chinese cloth bite mosquito repellent effect The mosquito repellent effect of American Sawyer CDC mosquito repellent effect Within 2 hours Mosquitoes are 0.5 cm away from the skin Mosquitoes are 0.5 cm away from the skin The mosquito is 1-2cm away from the skin 2-3h Mosquitoes are 0.1cm away from the skin Mosquitoes are 0.5 cm away from the skin Mosquitoes are 0.5 cm away from the skin 3-4h Mosquitoes stay for 1 second and fly away Mosquitoes are 0.1cm away from the skin Mosquitoes are 0.5 cm away from the skin 4.5-5h Mosquitoes start biting Mosquitoes are 0.1cm away from the skin Mosquitoes are 0.5 cm away from the skin 5-6h - Mosquitoes stay for 1 second and fly away Mosquitoes are 0.1cm away from the skin 6.8-7h - Mosquitoes start biting Mosquitoes are 0.1cm away from the skin 7-9h - - Mosquitoes stay for 1 second and fly away 9-10h - - Mosquitoes stay for 1 second and fly away

[0158] Based on the above experimental data, the mosquito repellent time concentration predictions of CDC, American sawyer and Chinese buding were obtained. Fig.17 .

[0159] It can be seen that the mosquito repellent cream product CDC of Example 4 has an effective mosquito repelling time of 6.8 hours, which is at least 3 hours longer than the mosquito repellent cream (American Sawyer) of Comparative Example 3 with the same DEET concentration, and at least 5 hours longer than the mosquito repellent cream (Chinese Bu Ding) of Comparative Example 4 with the same DEET concentration.

[0160] Conclusion: In summary, the sustained-release duration of active ingredients and the mosquito-repelling effect of the products of Examples 1-4 prepared according to the formulation and preparation method of the present invention are superior to those of Comparative Examples 1-4 with the same concentration.

[0161] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A mosquito repellent cream, characterized in that: It includes a lipophilic emulsified mixture phase A mixture, a hydrophilic mixture phase B mixture and a thickening mixture phase C mixture, measured by weight. Phase A mixture includes 18-20 parts of stearic acid, 10-32 parts of liquid paraffin, 3 parts of glyceryl monostearate, and 10 parts of polyethylene glycol monostearate; Phase B mixture includes 6-20 parts of glycerin, 0.2 parts of Kaisong CG, and 89-93 parts of distilled water; The phase C mixture includes 6.7-10 parts of cross-linked polyvinyl pyrrolidone and 20-40 parts of DEET.

2. The mosquito repellent cream according to claim 1, characterized in that: The hydrophilic mixture B phase mixture also includes 0.2 parts of xanthan gum.

3. The mosquito repellent cream according to claim 1, characterized in that: The lipophilic emulsified mixture phase A mixture also includes 10 parts of white vaseline, 4 parts of cetearyl alcohol, and 8 parts of hexadecyl alcohol.

4. The mosquito repellent cream according to claim 1, characterized in that: The lipophilic emulsified mixture phase A mixture also includes 4 parts of cetearyl alcohol and 4 parts of hexadecyl alcohol.

5. The mosquito repellent cream according to claim 1, characterized in that: The lipophilic emulsified mixture phase A mixture also includes 5 parts of cetearyl alcohol and 4 parts of hexadecyl alcohol.

6. The method for preparing the mosquito repellent cream according to any one of claims 1 to 5, characterized in that: The steps include: S1. Weigh the materials according to the formula, and then mix them into a phase A mixture, a phase B mixture and a phase C mixture respectively; Heat the phase A mixture to 85°C and set aside; After heating the phase B mixture to 90°C, perform air drying for 3 minutes, and immediately perform rapid cooling after air drying for standby use; S2, pouring the phase B mixture treated in step S1 into the phase A mixture treated, homogenizing with a high-speed homogenizer for 5 minutes, rapidly cooling in an ice bath, and standing for 15 minutes to obtain an emulsion; S3, after heating the emulsion to 45°C, add the C phase mixture, and stir with a homogenizer for 30 minutes until uniform, and introduce nitrogen gas during the stirring process; S4. After cooling the mixture to 35° C., stirring was stopped. Within a time window of 3 minutes after stirring was stopped, the mixture was rapidly cooled to obtain a finished product.

7. The preparation method according to claim 6, characterized in that: In step S1, the temperature of the rapid cooling treatment is -15°C, and the time of the rapid cooling treatment is 30 minutes.

8. The preparation method according to claim 6, characterized in that: In step S2, the time for rapid cooling in an ice bath is 30 min.

9. The preparation method according to claim 6, characterized in that: In step S5, the specific method for rapidly cooling the mixture is: within a time window of 3 minutes after stopping stirring, rapidly cooling the mixture at -15°C for 2 hours.

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