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>Home>Blog>Anti-mildew, antiseptic Kathon CG (CMIT/MIT CG)bacteria and its application in cosmetics

Author: Fu Qingou Wang Liping Wang Fengling

Abstract, The bactericidal action of Kathon CG (CMIT/MIT CG) were tested. The tests show that it has effective broad spectrum bactericidal action and good compatibility with ionic or/and nonionic surfactants at concentration of 0.02-0.05%. It is really toxicless and effective in the range of PH value for cosmetics.

Kathon CG (CMIT/MIT CG) is an aqueous solution of 1.5% CMIT and MIT mixture produced by me. The appearance is amber and clear liquid. Magnesium salt is added as a stabilizer. It is soluble in ethanol, ethylene glycol and water. Ionic surfactants, emulsifiers and proteins are compatible, and the concentration of amine solution can affect the activity of its active ingredients. It can be stored at room temperature for more than one year.

  1. Toxicity test

Acute toxicity:

Oral LD 50 (rat)

Oral LD50 (rat): female 3160mg/kg; male: 3480mg/kg

Transdermal LD50 (rat): >5000mg/kg

Subacute toxicity:

Rats and dogs were fed for 90 days with 448ppm and 840ppm of active ingredients per day, respectively, and no death and any pathological changes were found.

Non-mutagenic, non-teratogenic and non-carcinogenic.

Irritation test:

eye irritation test (rabbit) for 4 weeks (8 times a day, 5 days a week), no irritation below 56ppm of active ingredients, skin irritation test (rabbit) for 90 days, the highest dose per kilogram of body weight per day is 0.4mg , with no associated pathological effects.

Phototoxicity test:

(guinea pig) no phototoxic effect

 The test strains were purchased from the National Culture Collection Committee and were isolated from various commercial cosmetics.

Cosmetics are provided by Beijing No. 4 Daily Chemical Factory and Beijing Liyuan Daily Chemical Factory.

Antibacterial spectrum of Kathon CG(CMIT/MIT CG)

  1. The MIC values of molds and yeasts were obtained by direct plate coating method:
  2. Kathon CG(CMIT/MIT CG)
  3. solutions of different concentrations were quantitatively added to the prepared and melted PDA medium with a sterile syringe, and then the medium containing Kathon CG (CMIT/MIT CG)was added. Pour it into a sterilized petri dish, and after the petri dish is naturally cooled, use a special pencil to radially divide the bottom of the petri dish into six equal parts and number them, and then use an inoculation needle to spread the number of aliquots radially in turn in each equal part. Plant the test bacteria and cover the petri dish. Put it in a constant temperature incubator (30 ℃) to observe the growth of the mold. If a certain concentration of the drug grows aseptically in the petri dish, it is the safe minimum concentration (MIC) of the drug against the bacteria (see Table 1).
  4. The MIC value of bacteria adopts the test tube dilution culture method: add 10 ml of liquid culture medium for bacteria to the bacterial tubes, plug them with cotton plugs, and after autoclaving, add different concentrations of Kathon CG (CMIT/MIT CG)respectively, and then insert them under aseptic conditions. A certain amount of the test bacterial solution (0.1ml, 10 -5 ~ ng, kg ) was placed in a constant temperature incubator (37°C) for 24 hours, and the turbidity of the bacterial solution was observed. When the degree is the same as that of non-inoculated bacteria, it is the complete inhibitory minimum concentration (MIC) of the agent on this strain.
  5. High temperature resistance test – the effect of temperature on the antibacterial ability of Kathon CG(CMIT/MIT CG)

A number of filter paper discs with a diameter of 25 mm were soaked in 500 ppm Kathon CG (CMIT/MIT CG)solution for 16 hours, taken out to dry, placed in each watch glass, baked at different high temperatures for a certain period of time, and taken out. A medium plate containing Pseudomonas aeruginosa was made, and Kathon CG (CMIT/MIT CG)discs treated at each high temperature were placed in the center of the petri dish. Three parallels were made for each temperature and compared with those without high temperature treatment. Put it in a constant temperature petri dish box for 24 hours and take it out, and use a caliper to measure the diameter of the inhibition zone

  1. PH resistance test–the effect of PH on the bacteriostasis of Kathon CG(CMIT/MIT CG)

Bacteria and PDA fungal culture mediums with different pH were prepared and inoculated with various bacteria and molds respectively, and the production status was observed regularly.

Sterilize the bacterial culture medium containing hydrolyzed milk protein and hydrolyzed casein respectively, add Pseudomonas aeruginosa suspension containing 1 billion bacterial cells per milliliter when cooled to 45°C, mix well and inject into sterilized petri dishes (each dish contains 0.1 ml of bacterial solution). After the medium was solidified, a steel ring with a diameter of 8 mm was placed in the center, and a sterile syringe was used to fill the ring with different concentrations of Kathon CG (CMIT/MIT CG)solution, and three parallels were made for each concentration. After being placed in a constant temperature incubator for 24 hours, it was taken out, and the diameter of the inhibition zone was measured with a caliper.

The extract is made from the ingredients of Chinese herbal medicine commonly used in cosmetics, which are respectively added to the liquid medium for sterilization, and then Kathon CG (CMIT/MIT CG)solution of different concentrations is added. The mixed bacterial liquid of the body was added to the culture medium (0.1 ml of bacterial liquid was added to each test tube), and placed in a constant temperature incubator for 48 hours after turbidity.

  • Effects of various surfactants on the antibacterial effect of Kathon CG(CMIT/MIT CG)

Sterilize the liquid medium containing various ionic and non-ionic surface activities, add Kathon CG (CMIT/MIT CG)solutions of different concentrations respectively, and add 0.1 ml of the mixed bacterial liquid separated from the cosmetics to the test tube medium. After 48 hours in a constant temperature incubator, take out the turbidity.

Select several preservatives commonly used in cosmetics at present, compare with Kathon CG(CMIT/MIT CG)

, do the inhibition zone test on Pseudomonas aeruginosa and mixed mold in cosmetics, and measure the diameter of the inhibition zone with calipers to compare the size of the inhibition zone .

Store the cosmetics with Kathon CG (CMIT/MIT CG)added in the factory at room temperature, sample 1 gram per month, and test the cosmetics by colony counting method

Make agar medium for mold, bacteria and yeast respectively. Precisely weigh 1 gram (or 1 ml) of cosmetics, put it in 50 ml of sterile water and shake well, use a sterilized syringe to draw 0.5 ml of diluent and inject it into an agar petri dish, spread it evenly with a sterilized glass spatula, and place it in a 30°C constant temperature incubator Use a sterilized glass spatula to spread evenly, put it in a 30°C constant temperature incubator for 24-48 hours to observe the results, and calculate the number of viable bacteria per gram of cosmetics as follows

X = total number of colonies appearing on all petri dishes / number of petri dishes * dilution factor

As can be seen from Table 1: Kathon CG (CMIT/MIT CG)is a spectral bacteriostatic agent. It can completely inhibit the growth of bacteria at a concentration of 150ppm; it can completely inhibit the growth of yeast and mold at a concentration of 125ppm; it is especially sensitive to mixed bacteria isolated from cosmetics, and can be completely inhibited at a concentration of 100ppm.

  1. Test results of the effect of temperature on the bacteriostatic effect of Kathon CG(CMIT/MIT CG)

From the results in Table 2, the failure rate of Kathon CG (CMIT/MIT CG)at 50°C for 10 minutes is 5.5%, and the failure rate for 30 minutes is 6.3%; the failure rate for 10 minutes at 80°C is 4.5%, and the failure rate for 30 minutes is 4.5%. 8.1%; the failure rate at 120°C was 9.0% in 10 minutes and 15.9% in 30 minutes.

In the production process of cosmetics, the temperature generally does not exceed 100 ℃, and experiments have shown that the efficiency of Kathon CG (CMIT/MIT CG)at this temperature is more than 90%, so Kathon CG (CMIT/MIT CG)can be added in the production process of cosmetics.

  1. Test results of the effect of PH on the bacteriostasis of Kathon CG(CMIT/MIT CG)
  2. :
  • When the CG concentration is increased to 200ppm, it can effectively control any bacteria in the range of pH 3 ~ 8 (Table 3)
  • When the concentration of Kathon CG (CMIT/MIT CG)is above 150ppm, the PH in the range of PH 3 ~ 8 can inhibit the growth of mold 100%.

Experiments show that the optimum range of Kathon CG (CMIT/MIT CG)is PH5 ~ 8, the concentration of Kathon CG (CMIT/MIT CG)is about 200ppm (Table 4)

  1. Test results of the effect of hydrolyzed protein on the antibacterial effect of  Kathon CG(CMIT/MIT CG)
  2. :

The results of Experiment 4 showed that the effect of protein on the bacteriostasis of Kathon CG (CMIT/MIT CG)was great. If 1% hydrolyzed protein was added to the medium, the biological efficiency of Kathon CG (CMIT/MIT CG)was significantly reduced. At the concentration of 200PPM, the antibacterial rate of Kathon CG (CMIT/MIT CG)is 0; even if the dosage of KathonCG is increased by 500ppm, it still cannot make up for its biological efficiency, and the antibacterial power is only 66.2% and 63.5%. But when the amount of hydrolyzed protein is 0.1%, the concentration of Kathon CG (CMIT/MIT CG)is between 400 and 500ppm. (table 5)

  1. Experimental results of the effect of Chinese herbal medicine on the antibacterial effect of Kathon CG(CMIT/MIT CG)

Cosmetics are not only for skin care and cleansing, but also for nutrition. Experiment 5 investigated the effect of some commonly used Chinese herbal nutrient components on the bacteriostatic power of Kathon CG. The results showed that the addition of ginseng, safflower, Polygonum multiflorum, pearl powder, etc. to the medium had no adverse effect on the bacteriostatic activity of Kathon CG (CMIT/MIT CG)compared with the blank control (Table 6).

  1. Experimental results of the effect of various surfactants on the antibacterial effect of Kathon CG (CMIT/MIT CG)(Table 7)

In the production process of various cosmetics, a variety of surfactants must be added. The biological and physical properties of Kathon CG (CMIT/MIT CG)are consistent with anionic, cationic, zwitterionic and nonionic surfactants. The antibacterial activity of Kathon CG (CMIT/MIT CG)in cosmetics is generally not affected by these surfactants.

It can be seen from Table 7: Tween 80/60/20, Span60, peregal 0-15, lecithin, sodium stearate, etc. do not affect the biological efficiency of Kathon CG; The bacteriostatic activity of Kathon CG (CMIT/MIT CG)also has a synergistic effect; while sodium thiosulfate and cysteine hydrochloride have an antagonistic effect on the bacteriostatic activity of Kathon CG. This antagonism increases when the concentration of Kathon CG (CMIT/MIT CG)is increased to 400 ~ 500ppm. disappear.

  1. Experimental results comparing the bacteriostatic effect of Kathon CG (CMIT/MIT CG)with other preservatives:

At present, 50% of cosmetics in the United States have adopted this new preservative. Table 8 is a comparison of the antibacterial power of commonly used cosmetic preservatives.

It can be seen from Table 8 that these preservatives are effective against various molds in cosmetics, but Kathon CG (CMIT/MIT CG)ranks first in antibacterial activity. .

  1. The results of the shelf life of cosmetics after adding Kathon CG:

On the basis of a large number of antibacterial tests of Kathon CG, the effective shelf life of cosmetics with Kathon CG (CMIT/MIT CG)added by the manufacturer was studied (see Table 9).

From the test results, after 10 months of testing, the cosmetics with Kathon CG (CMIT/MIT CG)did not grow any bacteria, while the number of viable bacteria in the cosmetics without preservatives exceeded the standard.

Due to the limited time, the effective shelf life test was only done for 10 months. We believe that the shelf life of Kathon CG (CMIT/MIT CG)is much longer than 10 months.

After a lot of tests, Kathon CG (CMIT/MIT CG)is a good cosmetic preservative. Its MIC value for bacteria and fungi is 100-150ppm. Due to the interference of various factors in the production process of cosmetics, the actual dosage in cosmetics should be 0.02-0.05%. In this concentration range, it can play a good anti-corrosion and mildew-proof effect on various cosmetics. Kathon CG (CMIT/MIT CG)is a promising preservative. With the continuous development of application experiments, its new uses will surely be discovered and used more widely

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