Cosmetic components: Emulsifiers

When mixing two immiscible media (water and oil) a very unstable system is formed. At the first opportunity, it tries to separate into its component parts. In order for this not to happen, emulsifiers are introduced into cosmetics. The emulsifier molecule has an elongated shape, one pole of which is hydrophilic (facing the water), and the other - lipophilic (facing the oil phase). Due to the peculiarities of their structure, the emulsifiers are located on the interface between the oil and water phases, forming a thin layer that prevents the merging of suspended drops.

Emulsifiers stabilize the emulsion and prevent its delamination. Emulsifiers are components that can not be dispensed with. If the cream is unstable, it not only looks ugly. In it, extensive areas are formed on the boundary of the water and oil layer, where microbes readily inhabit. In addition, the nature of the distribution of active components changes, which may even lose their activity. Without emulsifiers it is impossible to create microemulsions that contain microscopic droplets of oils. Such emulsions are well distributed, quickly absorbed and help the active water-soluble components to reach deep layers of the skin.

The most powerful emulsifiers are detergents - detergent-acting surfactants (surfactants). Their direct purpose is to dissolve fats during cleaning, washing dishes, washing, etc.

Detergents are one of the cheapest emulsifiers. Almost every cream contains some amount of detergents. They are usually used to enhance the effect of other emulsifiers. When applied to the skin, detergents act on the lipid barrier of the skin in the same way as on all other fat formations - they build into it, break its ordered structure and break into individual droplets. Detergents are also toxic to cells, since they act destructively on the cellular lipid membrane. Like all surfactants, they can penetrate deep enough into the skin, down to the cells of the embryonic layer of the epidermis, which, of course, is not beneficial to the skin. Detergents and other surfactants are often the cause of allergic reactions and skin irritation. The toxic and irritating potential of all surfactants is different. We are more toxic cationic and anionic surfactants, non-ionic surfactants are softer. The classic skin irritant is sodium lauryl sulfate. But its ethoxylated analogue - sodium laureth sulfate - is much softer.

And yet, from the ability of surfactants to destroy the lipid barrier of the skin, one can also benefit. The fact is that many active additives are water soluble and can not penetrate independently through the epidermal barrier. By destroying the lipid layers between horny scales, surfactants increase the permeability of the epidermal barrier, allowing other substances to pass through it to the deeper layers of the skin. Properly selected and balanced surfactant systems increase the permeability of the stratum corneum to active components that otherwise would remain on the surface of the skin. However, the possibility of negative impact of surfactants on the skin should be taken into account, especially since it is impossible to predict how much and how often the consumer will apply this cosmetic to the skin. To reduce the harmful effect of surfactants, cosmetics manufacturers are trying to reduce their concentration in cosmetics, using them in combination with other emulsifiers.

As a surfactant, compounds can be used as natural (for example, phospholipids, fatty acids, waxes - bees, jojoba, candelilla, etc.), and synthetic and semi-synthetic. Among synthetic emulsifiers it is necessary to distinguish an extensive and diverse group of silicone surfactants - they are increasingly referred to as organosilicon compounds (from English silicon to silicon). These are relatively new cosmetic ingredients, products of long research and complex chemical synthesis, which gradually displace traditional organic surfactants. The fact is that silicones have proved to be biologically inert substances, in other words, they do not interfere with the biochemical processes taking place in the skin. This quality is very valuable for the components of the base, which must satisfy several criteria at once:

• be safe and inert to the skin (after all, they are usually present in the formulations in tangible concentrations);
• stay on the surface of the skin and not penetrate the stratum corneum;
• have good consumer characteristics;
• do not interact with the active ingredients of the formulation. Silicones combine all these properties and excel in this their organic counterparts.

In general, you can recommend to consumers the following:

• Do not use cheap cosmetics, as almost certainly it contains relatively many detergents, which are the cheapest and easiest way to stabilize emulsions.
• For sensitive, dry and damaged skin, you should use either very high-quality cosmetics or natural oils of restoring effect.
• To entrust the selection of a cream to an experienced specialist who knows how to "read" the list of ingredients and knows how various cosmetic products act on the skin.
• And also to study cosmetic chemistry, biology and medicine, which will allow you to obtain the necessary information about this cosmetic product not from the annotations to it and the commercial, but from the list of ingredients.

[1], [2], [3]