A brief description of traditional preservatives in cosmetics

Original title: A Brief Description of Traditional Preservatives in Cosmetics

□ Lu Feng

Cosmetics is a fine chemical product, mainly through spraying, smearing, etc., so that it covers the body's hair, skin, lips and teeth, fingernails and other parts. Cosmetics are rich in nutrients that allow microorganisms to grow, grow and multiply. In the production and use of cosmetics, it is impossible to achieve a completely sterile state, so it is inevitable that cosmetics contain some microorganisms. These microorganisms will make cosmetics deteriorate, fail, etc., easily cause damage to the user's epidermal protection system, and then allergic, ulcerated, and even cancerous, causing serious impacts on the user's health. Therefore, preservatives are an indispensable part of cosmetics, and their role is to inhibit the growth, growth and reproduction of microorganisms.

The Technical Specification for the Safety of Cosmetic Products (2015 Edition) mentions that the definition of preservatives refers to substances that are added to cosmetic products for the purpose of inhibiting the growth of microorganisms in such cosmetics.

The breeding, growth and reproduction of microorganisms require oxygen, temperature, water, growth factors and other factors. In other words, as long as the above factors are cut off, it can effectively prevent the breeding, growth and reproduction of microorganisms. Therefore, the mechanism of action of preservatives can be summarized as follows:

Cut off the water source If the cosmetics themselves are ointment-like and the water content is extremely low, it is difficult for microorganisms to breed, grow and multiply;

Changing the growth environment of the pH microorganism of the product requires the phH value to reach 6.0 to 7.0, while the pH value of the fruit acid product is acidic, which is not suitable for the growth of microorganisms, and the antiseptic effect is better;

Changing the surface tension A large number of cationic surfactants are added to some cosmetics, which can effectively prevent the breeding, growth and reproduction of microorganisms;

Changing the temperature In general, the method of high temperature sterilization is adopted during the production period, and the low temperature preservation is used during the preservation period, which can effectively prevent the breeding, growth and reproduction of microorganisms;

Changing the living environment of osmotic pressure cells requires a suitable osmotic pressure, increasing the osmotic pressure will make the cell membrane dehydrated and damaged, reducing the osmotic pressure will make the cell membrane rupture due to water absorption, and the essence of all living things is the cell, changing the osmotic pressure can also prevent the breeding, growth and reproduction of microorganisms.

The main types of preservatives are divided into traditional preservatives and natural preservatives. Traditional preservatives mainly include the following categories:

Paraben is commonly used in methyl esters, ethyl esters, propyl esters and butyl esters, colorless or white crystals at room temperature, antiseptic mechanism is to destroy the cell membrane and then denature the proteins in the cell to prevent microbial growth, growth, reproduction. The maximum allowable use concentration stipulated in China is 0.8% of mixed esters, 0.4% of monoesters (all in acid terms), and the optimal use of ph range is 4 to 9.

Phenoxyethanol belongs to organic compounds, colorless viscous liquid at room temperature, often emits a faint fragrance, antiseptic mechanism is to destroy the cell membrane, inhibit oxidative phosphorylation coupling to achieve the purpose of preventing microbial breeding, growth and reproduction, mainly for gram-positive bacteria and gram-negative bacteria and Pseudomonas aeruginosa has an inhibitory effect, the best ph range of bacteriostatic is 3 to 9, the highest amount of addition is 1%.

Benzyl alcohol, also known as benzyl alcohol, is a colorless liquid at room temperature, with a strong burning taste and a slight aromatic odor, mainly on gram-positive bacteria, fungi, mold, yeast has a strong inhibitory effect, strong toxicity, but low concentration will not produce toxicity to the human body, and the antibacterial effect is obvious, the maximum allowable use is 0.1%.

Formaldehyde has excellent bacteriostatic effect, but it is low in safety and can cause cancer, so it is banned. There is a substitute on the market, that is, formaldehyde-releasing preservatives, which are relative to formaldehyde and its safety is guaranteed, but it can quickly release formaldehyde in water-soluble and polar media, so it must be used with caution. Formaldehyde is a broad-spectrum preservative that inhibits gram-positive bacteria, gram-negative bacteria, and effectively inhibits Pseudomonas, but only selectively inhibits mold and yeast.

Imidazolyl urea is one of the most widely used varieties of formaldehyde donor preservatives. Good water solubility and good compatibility. It has a good antibacterial synergistic effect with paraben complex. Its free formaldehyde concentration is very low, so it is relatively mild, has a strong effect on bacteria, and has a poor effect on fungi. Can not be used in infants and people sensitive to formaldehyde, the maximum allowable concentration is 0.6%.

Benzoic acid, also known as benzoin, is a colorless and odorless flake crystal. It has antibacterial activity, and the activity is the best when the pH is 2.5 to 4.0. Benzoic acid and its salts have a good effect on yeast and mold, and the dosage is generally 0.1% to 0.2%.

In addition, natural preservatives are non-polluting, mild and highly safe, so they have attracted widespread attention. China's development and utilization of natural preservatives still have a lot of space, in the development and utilization of natural preservatives to consider its safety, economy, etc., but no matter how much obstacle, natural preservatives will become the focus of the industry and the future development trend.

With the development of science and technology and people's continuous pursuit of beauty, natural anti-corrosion, green anti-corrosion, additive-free anti-corrosion system will surely become the direction of future cosmetics anti-corrosion system development. (Lv Feng)

Editor-in-Charge: Xiao Yun

【Source: China Medical News】

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