Talking about the development trend of cosmetics preservatives
Everyone has a heart for beauty, and the research on cosmetics has never stopped since ancient times. As we all know, cosmetics have the functions of whitening, moisturizing, and moisturizing. These functions are attributed to the effects of various effective ingredients. Most of them are oil or nutrient ingredients, which are very susceptible to microbial infection and spoilage, resulting in deterioration of product quality. Preservatives are substances that can prevent the growth of microorganisms in the product. In cosmetics, the role of preservatives is to prevent the product from being contaminated by microorganisms, extend the shelf life of the product, and ensure the safety of the product. As people have increasingly diverse functional requirements for cosmetics, and more active ingredients are used in cosmetics, choosing an efficient and safe antiseptic system is a concern of current cosmetic formulators. The following is a brief introduction to the mechanism, types, evaluation indicators and development trends of preservatives.
1. The general mechanism of action of preservatives
Preservatives are essentially protective agents that inhibit and kill microorganisms in cosmetics and maintain the quality of cosmetics for a long time. Preservatives are not bactericides. They do not have a strong immediate bactericidal effect. They can only take effect when they are in sufficient concentration and in direct contact with microorganisms. Preservatives inhibit the growth of cells by inhibiting the synthesis of basic metabolic enzymes in cells or the synthesis of nucleic acids and proteins of important vital substances.
2. Factors affecting the effect of preservatives
The effect of preservatives is related to many factors
2.1 The effect of pH
The change of pH value affects the dissociation of organic acid preservatives and thus the activity of preservatives. For example, 2-bromo-2-nitro-1,3-propanediol is very stable at pH=4, and its activity can be maintained at pH=6. In a year, the activity is only a few months at pH=7.
2.2 The influence of solid particles and gels
Some cosmetics contain powder particles such as kaolin, aluminum magnesium silicate, etc., which can adsorb preservatives and cause loss of activity of the preservatives. However, some adsorbents adsorb the preservatives while also adsorbing the bacteria in them, so that they can be placed in high concentrations for preservatives. Strengthen its antibacterial effect in the agent. The combination of preservatives and water-soluble polymer gels reduces the concentration of free preservatives in the formulation and reduces its effectiveness.
2.3 The effect of solubilization of nonionic surfactants
Various surfactants in cosmetics, especially non-ionic surfactants and preservatives, will form a solubilization-complexation effect and affect the activity of preservatives. Oil-soluble non-ionic surfactants (HLB=3-6) have a greater deactivation effect on preservatives than water-soluble non-ionic surfactants with high HLB value.
2.4 The effect of deterioration of preservatives
Some factors will affect the deterioration of the preservative itself, thereby reducing the preservative effect. Such as the decomposition of preservatives caused by light and heating, the failure caused by biochemical reactions or the sterilization process of radiation
