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Classification Of Preservatives
Jun 11, 2018

Most of the preservatives react with the cell membrane, react with certain components of the cell wall, mainly with proteins, destroy the protective structure of the microbial cells or interfere with the metabolism of the cells, affect the normal growth order of the cells, and thus achieve anti-corrosion For the purpose, cations are mainly sterilized by affecting their osmotic pressure, breaking the cell membrane, shrinking and losing water.

According to the dozens of preservatives that are commonly used in the cosmetics field today, they are classified according to their active substances.

3.1 imidazolidinyl urea

Germall 115, Germall II, Germaben II-E, Germallplus, Germall IS-45 from ISP. In the Jaime series, the main ingredient is imidazolidinyl urea, which is a donor of formaldehyde. It can be used for sterilization by slowly releasing formaldehyde during the application process. The main component of Germall 115 is imidazolidinyl urea. Its antibacterial activity is poorer than that of Germall II (diimidazolidinyl urea). Germaben II-E is a compound of parabens. It is better than single component in the treatment of mold and yeast. There are advantages. Germallplus, Germall IS-45 is a formulation of iodopropynylbutylcarbamate. The market response is also good, but take care to avoid the ingredients that may inhibit the activity that may exist in the formula. In addition, 1% of iodopropyl in preservatives. Alkynyl butyl carbamate is poorly water-soluble, and if it is not dissolved with organic solvents during operation, it may also affect its anti-corrosion effect. Germall IS-45 is a relatively new species sold by ISP, which contains 5% methylparaben, which enhances the ability to inhibit mold and yeast.

3.2 Endoyl urea

LONZA's glydantplus, DDMMH, NIPA's DMDMH. This product is also a formaldehyde donor. Glydantplus is a formulation of iodopropynylbutylcarbamate with a content of iodopropynylbutylcarbamate of 5%. In addition, LONZA also supplies liquidglydantplus (propylene glycol solution), which is said to have 50% active material. It is also important to note that the reducing agents in the formulation may inhibit it.

3.3 Isothiazolone

Kathon CG, 950 from Rohm and Haas, isocilpc from LONZA, EUXYLK100, EUXYLK727 from S&M. This product is also a formaldehyde donor. LONZA's isocilpc is composed of two isothiazolinones. The addition of a 23% magnesium salt in the formula is synergistic, mainly to change the osmotic pressure. K727 is a compound of methyl dibromoglutaronitrile. EUXYLK100 is a compound of benzyl alcohol, which also has considerable anti-corrosion capability for the gas phase.

3.4 Nipagin esters (parabens)

Zhejiang Shengli, ISP's Liquaparoil, S&M's EUXYLK300, NIPA's phenonip, etc. This type of preservative is currently one of the most widely used preservatives, but the amount is relatively large, with the growth of the carbon chain, its water-soluble phase gradually deteriorates, affecting its distribution rate in the aqueous phase. Its mildew effect is more prominent. Nipagin methyl ester has the best water solubility and can often be added directly to the aqueous phase; whereas, ethylparaben, propyl ester, butyl ester, and isobutyl ester tend to dissolve in the oil phase.

Nipagin methyl ester is a preservative suitable for use in acidic systems. It has a maximum antimicrobial activity of 77% at pH 5, 63% at pH 7, and close to 50% at pH 8.5. Therefore, the activity of paraben esters in the system can be improved primarily by lowering the pH of the system, typically 7.0 to 6.5 or lower, although sometimes they can maintain their efficacy in slightly higher pH systems.

3.5 Quaternary ammonium salt-15

This type of product currently has Dowcil 200 from Dow Chemical. Dowicil200 will not thin formaldehyde, but its anti-oxidation and reduction ability is better than ISP's Jaime. In some easily discolored formulations, it is common practice to add a small amount of sulphite for prevention.

3.6 Domestic Kaisong-CG (chemical structure same as Category 3)

CY-1 of Zhejiang Shengxiao, MD-2000 of Shandong Mingda, Xinke-99 of Jiangsu Xinke, KS-1 of Shaanxi Huarun, and XF-1 of Xi'an Pioneer. This product is also a donor of formaldehyde. In terms of use, it is sensitive to the PH value and can play a very good antiseptic effect in the acidic environment. The amount is very small, about 0.08% can play a very good role. However, in an alkaline environment, it loses its antiseptic activity. In this type of product, in order to increase its anti-corrosion activity, magnesium salt is added in order to increase the osmotic pressure. Therefore, when using this product, the compatibility between raw materials must be taken into account in order to avoid precipitation, especially in the transparent In products, be very careful. In addition, amines, mercaptans, sulfides, sulfites, bleaches can also inactivate Kaisong.

3.7 In addition, benzoic acid/benzyl alcohol and derivatives antiseptics, alcohols and derivatives antiseptics,

Among them, phenoxyethanol, which is a very good solvent and preservative, is often used as a solvent to dissolve other oil-soluble preservatives in the formulation of preservatives, but it can be used as an emulsifier in itself. Therefore, when using it, consider its effect on the product itself. It should also be noted that phenoxyethanol is unstable under certain high pH conditions.

3.8 Benzoic Acid / Sodium Benzoate / Potassium Sorbate

Benzoic acid/sodium benzoate/potassium sorbate are mainly used in foods, so they are listed together. Its antiseptic action mechanism is: benzoic acid preservatives act with its undissociated molecules, and the undissociated benzoic acid has strong lipophilicity, easily passes through the cell membrane, enters cells, and interferes with the permeability of microorganisms such as molds and bacteria and cell membranes. Impedes the absorption of amino acids by the cell membrane, enters the benzoic acid molecules in the cells, acidifies the alkali in the cells, and inhibits the activity of the respiratory enzymes in the cells of the microorganisms, thereby playing a role in preservation.

These preservatives also belong to the class of acidic systems. Sorbic acid and benzoic acid are inactive at pH 7 and exhibit 37% and 13% activity at pH 5, respectively, and should therefore be used in acidic media.

3.9 Bropor

Bronopol is an abbreviation for 2-bromo-2-nitro-1,3-propanediol. It has a broad-spectrum bacteriostatic effect and can effectively inhibit most bacteria, especially against gram-negative bacteria. Excellent results. It is unstable under high temperature and alkaline conditions and darkens under sunlight. BROMOPOL can be compatible with most surfactants, but substances that contain -SH groups in the cosmetic raw materials, such as cysteine, can reduce BLOPOL's antibacterial activity. In addition, metallic aluminum can also reduce the antimicrobial activity of Bropor.

3.10 IPBC

IPBC English name 3-iodo-2-propynyl-butyl-carbamate, the main component of iodopropynyl butyl carbamate, with a broad-spectrum antibacterial activity, especially for mold and yeast have a strong killing effect. Good compatibility, can be compatible with the various components present in cosmetics, the test results show that its antibacterial ability is not affected by surfactants, proteins and herbal additives.

3.11 Trichloroxin

Trichlorin's new INCI name is Triclosan and can be used as a preservative at low levels. When the amount is high, due to the extensive and highly effective killing and inhibition of infection or pathogenic gram-negative bacteria, fungi, yeasts and viruses (such as A, B, rabies, and HIV), Also used in sterilization products.

In the case of high concentration, as a bactericide, the mechanism is that it can directly destroy the bacterial cell membrane, causing irreversible denaturation of proteins and nucleic acids in the cytoplasm, resulting in leakage of low-molecular-weight intracellular soluble substances and death of bacteria.

In the case of low-concentration use, as a bacteriostatic agent, its mechanism is to act on the bacterial cell membrane, impede the absorption of nutrients such as amino acids, uracil, etc. necessary for the growth of bacteria, thereby inhibiting the production of bacteria, at extremely low concentrations (MICs). ) And can play this role.

There are many kinds of preservatives, and they are numerous. Here is a list of the more commonly used types in the cosmetics field. In general, most preservatives are sensitive to strong redox chemicals because they chemically interact with the various targets in the microbial cells, interfering with the cell's metabolism and destroying the cell's structure. Quaternary ammonium salts, etc., are preserved by affecting the osmotic pressure of microbial cells. When using preservatives, the effects of various components of the formula on preservatives should be considered in order for the preservative to perform its fullest role.