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Glycolic acid structural formula. Hydroxy acids (hydroxy acids)

Hydroxy acids (alcohol acids) are derivatives of carboxylic acids containing one, two or more hydroxyl groups in the radical connected to the carboxyl.

Depending on the number of carboxyl groups, hydroxy acids are divided into monobasic, dibasic, etc.; depending on the total number of hydroxyl groups, hydroxy acids are divided into mono- or polyhydric.

According to the nature of the hydroxy acid radical, there are limiting and non-limiting, acyclic, cyclic or aromatic.

The following types of isomerism occur in hydroxy acids:

structural(radical chain isomerism, isomerism of the mutual position of carboxyl and hydroxyl);

optical(mirror) due to the presence of asymmetric carbon atoms.

The names of hydroxy acids are given by the name of the acid with the addition of "hydroxy" or "dioxi", etc. The trivial nomenclature is also widely used.

physical properties. Lower hydroxy acids are most often thick, syrupy substances. Hydroxy acids are miscible with water in any ratio, and with increasing molecular weight, the solubility decreases.

1. Acidic properties - hydroxy acids give all the reactions characteristic of carboxyl: the formation of salts, esters, amides, acid halides, etc. Hydroxy acids are stronger electrolytes than their corresponding carboxylic acids (the influence of the hydroxyl group).

2. Alcoholic properties - reactions of hydrogen substitution of the hydroxyl group, the formation of ethers and esters, the substitution of -OH for halogen, intramolecular dehydration, oxidation.

chloroacetic glycolic glyoxal

acid acid acid

a) HO-CH 2 -COOH + CH 3 OHHO-CH 2 -CO-O-CH 3 + H 2 O

ester of glycolic acid and methyl alcohol

b) NO-CH 2 -COOH + 2CH 3 ONCH 3 -O-CH 2 -COOSH 3 + 2H 2 O

glycolic methyl methyl ether

acid alcohol methoxyacetic acid

3. The ratio of hydroxy acids to heating - when heated, α-hydroxy acids split off water, forming a cyclic ester built as an id of two molecules of α-hydroxy acids:

α-hydroxypropionic acid lactide

β-hydroxy acids under the same conditions easily lose water with the formation of unsaturated acids.

BUT-CH 2 -CH 2 -COOH CH 2 \u003d CH-COOH

β-hydroxypropionic acrylic acid

γ-hydroxy acids can also lose a water molecule with the formation of intramolecular esters - lactones.

BUT-CH 2 -CH 2 -CH 2 -COOH

Some hydroxy acids are obtained from natural products. So, lactic acid is obtained by lactic acid fermentation of sugary substances. Synthetic production methods are based on the following reactions:

1) Cl-CH 2 -COOH + HOH HO-CH 2 -COOH;

2) CH 2 \u003d CH-COOH + HOH
BUT-CH 2 -CH 2 -COOH.

acrylic acid β-hydroxypropionic acid

Glycolic (hydroxyacetic) acid - a crystalline substance found in unripe fruits, in beet juice, turnips and other plants. In industry, it is obtained by the reduction of oxalic acid. It is used for dyeing (calico printing).

Lactic acid (α-hydroxypropionic) - thick liquid or low-melting crystalline mass. Lactic acid is formed in the process of lactic acid fermentation of sugars, under the action of lactic acid bacteria. Contained in fermented milk products, sauerkraut, silage. It is used in mordant dyeing, in leather production, in medicine.

Meat-lactic acid is found in the muscle juice of animals and meat extracts.

diatomic glyceric acid participates in the life processes of plants and animals.

Ascorbic acid (vitamin C) - a crystalline substance contained in fresh fruit, lemons, black currants, in fresh vegetables - cabbage, beans. Synthetically, vitamin C is obtained by oxidation of the polyhydric alcohol sorbitol.

α-ascorbic acid

Ascorbic acid is easily decomposed by atmospheric oxygen, especially when heated.

Acyclic two- and tribasic hydroxy acids.

Apple (oxysuccinic) acid (HOOC-CHOH-CH 2 -COOH) is a crystalline substance, highly soluble in water; used in medicine, found in unripe rowan, barberry, rhubarb, grape juice, wine.

Wine (tartaric, dioxysuccinic) acid (HOOC-*CHOH-*CHOH-COOH) has 2 asymmetric carbon atoms and therefore has 4 optical isomers. Forms acidic potassium salts, which are poorly soluble in water and precipitate. Salt crystals can be observed in wine (tartar). The mixed potassium-sodium salt is called Rochelle salt. Salts of tartaric acid are called tartrates.

tartar, rochelle salt

Tartaric acid is common in plants (mountain ash, grapes, etc.).

Lemon acid
found in citrus fruits. In industry, it is obtained from lemon fruits, by the oxidation of sugars by mold fungi, during the processing of spruce needles.

Citric acid is a biologically important compound that takes part in metabolism. Used in medicine, food, textile industry as an additive to dyes.

Cyclic monobasic polyhydric hydroxy acids are part of bile acids and other physiologically important compounds; for example, auxin enhances plant growth.

Aromatic hydroxy acids subdivided into phenolic acids and aromatic fatty acids containing hydroxyl in the side chain.

o-hydroxybenzoic mandelic acid

Salicylic acid found in some plants in free form (calendula), but more often in the form of esters. In industry, it is obtained by heating sodium phenolate with carbon dioxide. It is used as a disinfectant and in the synthesis of dyes. Many derivatives of salicylic acid are used as medicines (aspirin, salol).

aspirin salol (phenyl ether

(acetylsalicylic acid) salicylic acid)

Gallic acid (3,4,5-trioxybenzoic).

Contained in tea leaves, oak bark, pomegranate tree. In industry, it is obtained from tannin by boiling with dilute acids. It is used for the manufacture of ink, in photography, in medicine as an antiseptic. Gallic acid and its derivatives are widely used as preservatives for many food products(fats, high-grade soaps, dairy products), has tannic properties and is of particular importance in the manufacture of leather and in stain dyeing.

mandelic acid refers to fatty aromatic acids (C 6 H 5 -CH (OH) -COOH), found in amygdalin, mustard, elderberry, etc.

Tannins are often derivatives of polyatomic phenols. They are part of plants and are obtained from extracts of bark, wood, leaves, roots, fruits or growths (galls).

Tannins are the most important tannins. This is a mixture of various chemical compounds, the main of which are esters of gallic and digallic acids and glucose or polyhydric alcohols.

Tannin exhibits the properties of phenols and esters. With a solution of ferric chloride, it forms a black complex compound. Tannins are widely used as tanning extracts, mordants for dyeing cotton fabrics, as astringents in medicine (they have bactericidal, hemostatic properties), and are preservatives.

Lipids include organic substances, many of which are esters of macromolecular fatty acids and polyhydric alcohols - these are fats, phosphatides, waxes, steroids, macromolecular fatty acids, etc.

Lipids are found mainly in plant seeds, nut kernels, and in animal organisms - in adipose and nervous tissues, especially in the brain of animals and humans.

Natural fats are mixtures of esters of the trihydric alcohol glycerol and higher carboxylic acids, i.e. mixtures of glycerides of these acids.

ABOUT General formula for fat:

where R I R II R III - hydrocarbon radicals of higher fatty acids of a normal structure with an even number of carbon atoms. Fats can contain residues of both saturated and unsaturated acids.

C 3 H 7 COOH - oil (contained in butter), etc.

C 17 H 29 COOH - linolenic, etc.

Get fats from natural sources of animal and vegetable origin.

Physical Properties fats are due to the acidic composition. Fats containing predominantly saturated acid residues are solid or ointment-like substances (mutton, beef fat, etc.). Fats, which contain mainly unsaturated acid residues, have a liquid consistency at room temperature and are called oils. Fats do not dissolve in water, but dissolve well in organic solvents: ether, benzene, chloroform, etc.

Chemical properties. Like all esters, fats undergo hydrolysis. Hydrolysis can proceed in an acidic, neutral or alkaline environment.

In the tale of the Little Humpbacked Horse, the tsar was promised youth after bathing in three cauldrons. One was with cold water, but the other two were with boiling water.

The experience was not successful. The king, as you know, boiled. Some cosmetic procedures the real world also seem fabulous.

So, at first glance, the idea of rejuvenating by injecting acid into the skin is crazy. However, doctors and cosmetologists say that acid and acid are different.

An example is glycolic. Its injections stimulate cell activity. They begin to renew themselves faster and produce more collagen, which is responsible for the elasticity of the integument.

As a result, wrinkles disappear, skin elasticity increases. Here it is, a tool worthy of kings, and at the same time, information, is it really so.

Properties of glycolic acid

Glycolic acid is a clear liquid. The presence of a yellowish color is evidence of the technical sense of the substance, that is, of low purification.

The color comes from impurities. In its pure form, the glycol compound is transparent and belongs to low toxicity.

Those who have given injections will remember that a couple of days after the procedure, the skin was reddened and swollen. But, the result, noticeable after the departure of edema, is long-term and more important.

Glycolic acid is not volatile, which makes it easier to work with the compound and use it.

If we talk about the use in cosmetology, then the size of the molecules of the substance also helps.

They are so small that they easily penetrate the skin. Why then injections? It's about the depth of penetration.

Acid from superficial creams cannot reach the deep layers of the dermis - the layer of skin that lies under the keratinized cells of the epidermis.

The size of acid particles is indicated by their molecular weight. He does not even reach 77. This is the molecular weight of hydroxyacetic acid.

This is because two names hide one connection. He also has a third name - hydroxyethanoic acid.

The names are justified by the formula of the substance: - C 2 H 4 O 3. Recording ethane: - C 2 H 6. The formula for ordinary acetic acid is: - C 2 H 4 O 2.

The prefix "hydroxy" indicates the simultaneous presence of carboxyl and hydroxyl groups in the acid. The latter is written as OH and the former as COOH.

Of the group of hydroxy acids, glycolic belongs to the simplest, containing only one hydroxyl, and only one carboxyl group at a minimum distance from each other.

Such glycolic acid formula determines its chemical properties. The low mass makes the compound easily soluble in water.

The most sparingly soluble hydroxy acids in the series have the greatest weight. Typical chemical reactions include the formation of esters, acid halides, amides, and salts.

They owe their education to the presence of a carboxyl article in the heroine. Thanks to him, hydroxy acids borrow some of the properties of carboxylic acids, whose derivatives they are.

The second half of the properties are taken from alcohols. So, composition of glycolic acid allows you to replace the hydrogen of the hydroxyl group. In this case, esters are formed, both simple and complex.

The hydroxyl group in glycolic acid can also be replaced by a halogen. Oxidation and intramolecular dehydration, that is, the splitting off of water molecules, also pass easily.

Their disconnection occurs when heated. As a result, unsaturated acids are obtained. So called compounds with double, unsaturated bonds in molecules.

It remains to find out in the course of which reaction glycolic acid. Reviews industrialists are usually affected by three methods for obtaining a reagent.

The first, so to speak, is used in the old fashioned way. The second is a novelty that is being tested. The third method is " old friend”, which is better than the new two.

Extraction of glycolic acid

The classic is the preparation of a glycol compound from monochloroacetic acid and calcium carbonate. Their interaction takes place when heated.

The decomposition reaction leads to the formation of oxalic acid and the calcium salt of glycolic acid. It remains to detach calcium from it.

The process is long-term, and this is the main problem. Glycolic acid has time to oxidize. Industrialists receive only 25-30 percent output.

Saponification of mychloroacetic acid helps to increase acid production. It is exposed to a solution of caustic steam.

The same sodium glycolic acid is formed. A solution of copper sulfate and a slightly soluble copper salt are added to it, decomposing the latter with hydrogen sulfide.

This cycle is faster. Less than half of the glycolic acid has time to oxidize.

The third method of industrial production of a glycol compound is the condensation of carbon monoxide with formaldehyde.

Carbon monoxide is CO. Formaldehyde, or, as it is also called, formic aldehyde, is written as follows: - HCHO.

The condensation takes place under pressure in the presence of catalysts. The latter are acids. The yield of the glycol substance is about 65%.

Application of glycolic acid

Having touched on the topic of cosmetology at the beginning of the article, we will reveal it to the end. The compound is used in several salon procedures.

First - peeling with glycolic acid. It belongs to the category of chemical, that is, keratinized cells are not exfoliated due to friction, but by softening dead tissues.

Glycolic acid gel destroys them in just a few minutes, simultaneously saturating the lower layers of the skin.

After, the beautician removes softened tissues, applying a caring cream. At the same time, the client feels only a slight tingling sensation.

Glycolic acid on the skin applied to open pores, improve complexion, as well as lighten it.

The bleaching properties of the solution come in handy when working with age spots and freckles.

Peeling also allows you to nullify small scars, smooth them out. By removing layers of skin, the beautician also eliminates irregularities.

Internal acid injections are aimed at skin rejuvenation. Cells, of course, are shocked.

But, this is what makes them act, actively share, resume the former level of production of collagen and hyaluronic compounds. The procedure is called mesotherapy.

The most gentle procedure is the application creams with glycolic acid.

Usually, it is advised as an additional care that accompanies a course of peels, or as a supportive effect of mesotherapy.

However, the cream can also be used separately. In this case, glycolic acid for face will give a minimal, but painless result.

Wrinkles will not go away, but the skin will become more elastic. This is the result of the production of proteins stimulated by the cream.

Outside of beauty parlors, glycolic acid is also often used to cleanse the skin.

Only now they mean the skins of animals that are used for shoes, sheepskin coats, bags, jewelry and household goods.

The heroine of the article is also capable of clearing the premises, therefore, it is added to household funds.

So, buy glycolic acid can be used as part of dishwashing liquids, or household appliances.

Industry lactic glycolic acid uses is not original. This is again cleaning, only now, industrial devices.

The low toxicity of the heroine of the article allows her to wash any food production machines, including conveyors. How much do industrialists pay for cleaning equipment? Let's find out.

Glycolic acid price

For ordinary people, the costs of industrialists remain a secret. For household needs, technical, that is, contaminated acid is used.

It is clear that the price tag for it should be lower than for the cleaned one. However, the sellers determine the exact cost during negotiations, because the deliveries are mainly wholesale.

The price tag is called based on the status of the client. Wins, of course, a regular customer. Affects the requests of sellers and the volume of the lot.

The more acids are ordered, the more impressive the discount. Things are obvious. Therefore, let's move on to the topic where you can "dig up" the specifics.

So, purified glycolic acid included in cosmetics. All of them - not from the budget.

So, a 100-ml bottle of peeling usually costs about 1,000. For 50-ml jars of creams of famous brands, they ask for 3,000-5,000 rubles.

This is the average cost. Sometimes, there are positions for a couple of thousand, or, on the contrary, 8000-15000 rubles.

A number of creams and gels are offered by cosmetic stores, and a number can be found in a pharmacy. Glycolic acid V detergents, oddly enough, does not increase their cost to several thousand rubles.

Conclusion: - The price tag for skin care products is more based on people's willingness to pay for youth and beauty. The true cost of the glycol compound seems to be within everyone's reach.

GLYCOLIC ACID- formed from glycol and various acids; gives a number of salts similar to acetic acid. Dictionary of foreign words included in the Russian language. Pavlenkov F., 1907 ... Dictionary of foreign words of the Russian language

glycolic acid— glikolio rūgštis statusas T sritis chemija formulė HOCH₂COOH atitikmenys: engl. glycolic ac >Chemijos terminų aiškinamasis žodynas

Glycolic acid- or hydroxyacetic, i.e. acetic acid, in which one hydrogen of the methyl group is replaced by hydroxyl (see), CH2 (OH). CO2H, obtained by Strecker and Sokolov (1851) by boiling benzoyl glycolic acid (see. Hippuric acid) with diluted chamois ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

Glycolic acid- hydroxyacetic acid, the simplest aliphatic hydroxy acid HOCH2COOH; colorless crystals, odorless; mp 79 80 °C; dissociation constant K = 1.5 10 4; freely soluble in water and organic solvents. Contained in immature ... ... Great Soviet Encyclopedia

GLYCOLIC ACID- HOCH2COOH, the simplest hydroxycarboxylic acid, colorless. crystals with the smell of burnt sugar, mp 79 80 0С. Contained in unripe grapes, beets, sugar cane. It is formed during the oxidation of fructose ... Natural science. encyclopedic Dictionary

glycolic acid- hydroxyacetic acid ... Dictionary of chemical synonyms I

GLYCOLIC ACID- (hydroxyacetic acid) HOCH 2 COOH, mol. m. 76.05; colorless crystals with the smell of burnt sugar; m.p. 79 80 ... Chemical Encyclopedia

hydroxyacetic acid- glycolic acid ... Dictionary of chemical synonyms I

Lactic acid- (ac. lactique, lactic ac., Milchsäure, chem.), otherwise α hydroxypropionic or ethylidene lactic acid C3H6O3 \u003d CH3 CH (OH) COOH (cf. Hydracrylic acid); three acids are known that correspond to this formula, namely: optically inactive (M. acid ... ... Encyclopedic Dictionary of F.A. Brockhaus and I.A. Efron

THIOGLYCOLIC ACID— (mercaptoacetic acid) HSCH2COOH, mol. m. 92.11; colorless liquid with strong bad smell; m.p. Ch 16.5°C, bp 123°C/29 mmHg Art., 90 ° C / 6 mm Hg. Art.; 1.3253; 1.5030; 1446 kJ/mol; p … Chemical Encyclopedia

Elena Hernandez Marina Kryuchkova

Introduction

First appearing in cosmetics at the beginning 90 -s, a-hydroxy acids (alpha hydroxy acids, AHA) have rapidly conquered the cosmetic market. Today it is one of the most popular ingredients in a variety of cosmetic products.

In the material prepared by our editors together with specialists from raw materials companies, consultants from well-known professional cosmetic lines and practicing doctors, we will talk about the biological effects of AHAs in the skin, about the principles for developing AHA-containing drugs and about their use in cosmetological practice.

What's happenedAHA

Organic substances that have different functional groups are called compounds with mixed functions. These compounds also include hydroxy acids, which, along with the acid (carboxyl) group -COOH, have a hydroxyl (alcohol) group -OH. According to a common version of the nomenclature, the carbon atom to which the carboxyl group is attached is denoted by the letter a, the carbon following it - (3, and so on, in accordance with the Greek alphabet. In the case of sufficiently long chains, the atom farthest from the carboxyl is usually denoted co. Accordingly, if the hydroxyl group is located at the a-carbon atom, then such a compound is called a-hydroxy acid (AHA), at (3-atom - (3-hydroxy acid (BHA), etc. (Fig. 1).

Ce-hydroxy derivatives of carboxylic acids (AHA) are the most common in nature. They are obtained from the Sugar row of plants, as well as from some biological substances. For example, glycolic acid is released from sugar cane, dairy - from sour milk, wine - from old wine, lemon - from citrus fruits, and apple, as you might guess, from apples. Hydroxy acids derived from fruits are often referred to as fruit acids.

nosn 2 coosn 2 soon o / : \ o (C 2 H 2 0 2) x

glycolide SOSN 2 polyglycolide

carboxymethylhydroxyacetate

Rice. 2. Compounds resulting from the reaction of glycolic acid molecules with each other

G lycolic (hydroxyacetic) acid is the first and smallest in the series of hydroxy acids: it contains only two carbon atoms. Like other AHAs, glycolic acid is soluble in highly polar solvents (water, methanol, ethanol, acetone, acetic acid, ethyl acetate), sparingly soluble in ethyl ether, and practically insoluble in nonpolar hydrophobic saturated hydrocarbons. Glycolic acid molecules, reacting with each other, are able to transform into linear polyester oligomers, cyclic glycolide dimers, linear dimers, and polymers (Fig. 2). In combination with other AHAs, glycolic acid can also form biodegradable ester copolymers. The properties of these copolymers (decomposition rate, solubility in water, etc.) are determined by their composition and molecular weight. Microspherical particles, which are considered promising carriers, are made from copolymers that are poorly soluble in water. medicines.

Water-soluble forms of AHA are used in dermatological and cosmetic preparations, in which they act on the condition of the skin at the molecular, cellular and tissue levels.

Biological effectsAHA

The first mention of the cutaneous application of glycolic acid dates back to 1974. Van Scoth And Yu, studying the effect of various drugs in ichthyosis, they found that glycolic acid is able to control the process of keratinization of the epidermis, weakening the adhesion between corneocytes. A similar effect has been found in other AHAs. Subsequently, the therapeutic efficacy of AHA was established in all forms of hyperkeratosis. Further studies showed that AHAs easily cross the stratum corneum, reach the lower layers of the epidermis, and even pass through the basement membrane into the dermis (Fig. 3).

Exfoliating action

One of the main effects of AHAs - exfoliating - is related to their ability to loosen the cohesion (cohesion) of corneocytes. AHAs do not cause disaggregation of corneocytes in the upper layers of the stratum corneum, but affect the cohesion of corneocytes in its lower, younger layers (Fig. 3). In this they are fundamentally different from true keratolytic agents - strong acids, alkalis, thiols and denaturing substances such as urea and lithium salts in high concentrations.

The thickness of the stratum corneum in normal and pathological conditions is determined by two opposite factors - those that weaken the cohesion of corneocytes, and those that enhance it. Both covalent (for example, disulfide, peptide, and intersaccharide) and various non-covalent (including ionic) bonds take part in the cohesion of corneocytes. The most common non-covalent bond that does not have a pronounced ionic character is the hydrogen bond. It is very weak and is easily destroyed by agents such as lithium bromide, urea and alkalis, which act as chemical denaturants (chaotropic, i.e., disordering reagents). The intermolecular hydrogen bond is also weakened upon dilution with water due to competition between the molecules of the solute and the water molecules themselves, which are very prone to hydrogen bonding. Ionic bonds arise between oppositely charged groups - negative (for example, carboxyl, sulfate, phosphate) and positive (amino groups of basic amino acids).

H
Recall that the stratum corneum of the epidermis consists of corneocytes (horny cells), between which there is a lipid layer that holds them together. This layer is most developed in the middle of the stratum corneum, however, at the level of the transition of the granular layer to the stratum corneum, this layer is still weakly expressed. Here, there is still an aqueous phase between the cells, and the cohesion of corneocytes is carried out mainly due to ionic interactions. These interactions are due to the presence on the cell surface of charged groups of various biomolecules that make up cell membranes - mucopolysaccharides, glycoproteins, sulfur-containing sterols and phospholipids (Fig. 4) .

Ionic bonds and, accordingly, cohesion of corneocytes are determined by three main factors:

the distance between cells, in other words, between positive and negative groups on the surface of adjacent cells;

intercellular environment;

charge density, i.e., the number of positive and negative groups per unit surface of the cell walls of corneocytes.

By influencing one or more factors, it is possible to modulate the cohesion strength of corneocytes. Thus, when the stratum corneum is hydrated, the distance between corneocytes and, consequently, between the opposite charges of the cell walls of corneocytes increases, which leads to a decrease in the cohesive force.

As regards the distribution and density of various charged groups on the cell surface, this process is under the control of a number of enzymes. The most "mobile" are sulfate and phosphate groups, which are easily cleaved off by common epidermal enzymes, sulfatases and phosphatases. Amino and carboxy groups are more difficult to remove, so their number on the cell surface is more or less constant.

It has recently been found that in X-linked ichthyosis, there is an innate deficiency of sulfatase activity in skin fibroblasts, cultured keratinocytes, throughout the epidermis and in the stratum corneum, as well as in other tissues. Thus, the control over the number of sulfate groups is insufficient, and their density on the cell surface increases. As a result, the adhesion force between corneocytes increases, the desquamation process is inhibited, and the stratum corneum becomes thicker and denser than normal.

AHAs are effective in any form of hyperkeratosis. It is assumed that they affect the activity of some enzymes involved in the formation of ionic bonds. The exact mechanism of this process is not completely clear. Apparently, the effect on enzymes occurs simultaneously in several ways (Fig. 5). For example, it is known that AHAs can replace sulfate and phosphate groups in reactions catalyzed by sulfate transferases, phosphotransferases, and kinases. These enzymes are responsible for sulfation and phosphorylation of mucopolysaccharides, glycoproteins, sterols and phospholipids on the cell surface. It is also known that some AHAs directly inhibit the enzymatic activity of phosphotransferases and kinases. So, lemon acid significantly inhibits glucose-6-phosphotransferase and phosphofructokinase. In addition, AHAs can act as phosphate group acceptors to form phosphorylated AHAs.

D For small hydrophilic AHA molecules, the stratum corneum is not an obstacle: they easily overcome it and find themselves in the intercellular aqueous medium of the granular layer, where they interact with corneocytes. The smaller the AHA molecule, the better it passes through the stratum corneum. Glycolic acid has the best penetrating ability precisely because of its small size. Unlike hydrophobic retinoids, AHAs do not require specific binding receptors on cell plasma membranes. The weakening of the adhesion of corneocytes at the level of the granular layer contributes to their faster advancement into the stratum corneum and subsequent rejection (exfoliation). This serves as a signal for division and differentiation of underlying keratinocytes. Thus, the life cycle of the main cells of the epidermis - from the basal cell (keratinocyte) to the stratum corneum (corneocyte) - is reduced. Along with this, the thickness of the stratum corneum also decreases, which is determined by the rate of renewal of the epidermis and the rate of desquamation of scales from the skin surface.

An imbalance between the processes of exfoliation and cell division of the basal layer, combined with impaired differentiation of keratinocytes, underlies a number of pathologies, such as hyperkeratosis (ichthyosis, keratoderma), parakeratosis (psoriasis), dyskeratosis (Darni's disease, c. Bowen's disease). In aging skin, a decrease in the mitotic activity of basal cells is usually accompanied by delayed exfoliation, which leads to a thickening of the stratum corneum. In these cases, the use of AHA preparations is quite justified, since the result of their action is a decrease in the thickness of the stratum corneum and a faster renewal of the epidermis.

Influence on the barrier function of the stratum corneum

The question arises: will increased peeling lead to a weakening of the barrier function of the stratum corneum? fartasch et al. conducted a series of experiments in which, using morphological and biophysical methods, they investigated the effect of AHA on the stratum corneum. For three weeks, a 4% glycolic acid preparation was applied to the inside of the forearm of volunteers twice daily, and then the treated area was biopsied. Using electron microscopy, we studied: 1) morphology and thickness of the stratum corneum, 2) lamellar bodies and organization of lipid layers, and 3) adhesion of corneocytes. In addition, transepidermal water loss (TEWL) and stratum corneum hydration were assessed before and after treatment. It turned out that no morphological changes occurred in the nuclear layers of the epidermis: normal lamellar bodies were present in the cells of the granular layer, and the structure of the lipid layer in the stratum corneum did not change after skin treatment with glycolic acid. The TEWL index, by which the barrier properties of the stratum corneum are judged, also did not change. These data, along with those of other authors, suggest that AHAs specifically act on corneocyte cohesion without disrupting the stratum corneum barrier.

Moreover, there is evidence that some AHAs have a positive effect on the synthesis of ceramides, the most important components of the intercellular lipid layers of the stratum corneum. Studying the effect of lactic acid isomers on ceramide biosynthesis and the state of the stratum corneum barrier, scientists from the company Unilever found that lactic acid not only increased the total amount of ceramides in the stratum corneum, but also modulated the type of ceramides synthesized in cells. As is known, ceramides 1 play a special role in maintaining the integrity of the stratum corneum. They include long-chain polyunsaturated fatty acids, mainly linoleic acid (75-80%). They play the role of rivets in the lipid structures of the stratum corneum, penetrating adjacent lipid layers and fastening them to each other. With a deficiency of linoleate-containing ceramides 1 normal structure lipid barrier disrupted, resulting in an increase in the permeability of the stratum corneum. This occurs with atopic dermatitis, deficiency of essential fatty acids, acne. In experiments in vivo And in vitro It was shown that the L-enantiomer (optical isomer) of lactic acid stimulates the synthesis of ceramides 1 containing polyunsaturated fatty acid tails. Daily incubation of a culture of human keratinocytes in a medium containing 20 mM lactic acid changes the qualitative composition of synthesized lipids: in addition to ceramides 2, which are characteristic of lipid metabolism in cells in culture, ceramides 1 and 3 appear. an aqueous solution of L-lactic acid on the forearm of volunteers showed that the ratio of linoleate- and oleate-containing ceramides 1 increases dramatically.

The effect depended on which of the optical isomers of lactic acid was used. In experiments in vitro The L-form was much more effective than the D-form (300% and 100% increase in ceramide synthesis, respectively). In experiments in vivo only the L-isomer was found to be effective. Thus, the lotion with the L-form increased the synthesis by 48%, with the DL-form - by 25%, and the lotion based on the D-form had no effect. The effect on the barrier function of the epidermis is evidenced by measurements of TEWL in a skin area previously irritated with sodium lauryl sulfate. Treatment of this site with L-lactic acid accelerated the recovery of the barrier, while the D-form was ineffective.

The effect of AHAs on the biochemistry of epidermal lipids described in this work is one of the few known mechanisms of their action on the state of the epidermis.

Moisturizing action

A decrease in the cohesion of corneocytes affects another very important parameter, which largely determines appearance skin, - on the hydration of the epidermis. "A significant contribution to the overall hydration of the epidermis is made by water", which is held by a complex of hygroscopic molecules called natural moisturizing factor (natural moisturizing factor, NMF). Being in corneocytes, NMF provides elasticity and mechanical strength to horny scales. NMF is better developed in younger corneocytes. As corneocytes move towards noBepxHocnrNMF, it gradually degrades, and the horny scales become drier and more brittle. Rapid desquamation of horny scales and renewal of the epidermis leads to an increase in the content of functionally active NMF in the skin and, consequently, the water associated with it. The best moisturizing effect is characteristic of lactic acid, which, among other things, is directly included in NMF.

The water content as a result of the action of AHA is also increased due to other factors. Thus, hygroscopic AHA molecules are able to bind water and, penetrating into the skin, deliver it to the deep layers of the epidermis. In addition, strengthening the barrier function of the epidermis, as well as stimulating the synthesis of glycosaminoglycans (see below), increases the water-saving and water-retaining properties of the skin.

Anti-inflammatory and antioxidant action"LITAs have an anti-inflammatory effect, affecting inflammatory mediators, reducing the production of superoxide and hydroxyl radical, participating in the functioning of B- and T-lymphocytes.

Interesting and at first glance somewhat unexpected data on the photoprotective and anti-inflammatory effects of glycolic acid were obtained perricone And DiNardo. It was decided to test the common belief that glycolic acid treatment of the skin increases the sensitivity of the skin to solar radiation, in other words, causes skin photosensitivity. Two series of experiments were carried out. In the first series, the anti-inflammatory potential of glycolic acid was evaluated based on the erythema reaction. Two symmetrical areas on the back of volunteers were irradiated three times with the minimum erythemal dose (MED) of UV-B. Four hours after irradiation, a glycolic acid cream (oil-in-water emulsion, 12% glycolic acid, partially neutralized with ammonium hydroxide to pH 4.2) was applied to one site, and a placebo cream to the other. The areas were treated with cream 4 times a day. 48 hours after the last application of the cream, the size of the erythema was assessed. A significant reduction in erythema was noted in the area treated with the glycolic acid cream.

In the second series of experiments, four areas on the back of volunteers were exposed to radiation:

section I(control) served to establish the MED for this subject, and was not treated with anything after irradiation;

plot2 24 hours after irradiation, the MED was treated with two AN A products, a cleansing lotion and an oil-free moisturizing lotion (both contained 8% glycolic acid and had a pH of 3.25); processing was carried out within 7 days;

plot3 treated with the same AHA products as site 2 for 3 weeks before irradiation;

plot4 was treated in the same way as site 3, however, 15 min before irradiation for 6 min, it was subjected to chemical peeling with a 50% glycolic acid solution.

It turned out that the degree of erythema in site 2, which was treated with AHA products after irradiation, was 16% less than in control site 1. This suggests that the skin heals faster when treated with glycolic acid. Comparison of sections 1 and 3 showed that pre-treatment of the skin with glycolic acid increases its resistance to radiation by 2.4 times. Chemical peeling of the skin before irradiation (section 4) reduces the sun protection properties of the skin by almost 2 times compared to section 3, however, even in this case, the resistance of the skin to irradiation is 1.7 times higher compared to the control section 1. The data obtained indicate that glycolic acid it has a photoprotective effect, increasing the resistance of the skin to radiation. In addition, the treatment of irritated skin with glycolic acid leads to a faster disappearance of erythema.

The anti-inflammatory effect of different AHAs is expressed to varying degrees and is directly related to their antioxidant properties. Thus, a comparison of four AHAs - glycolic, lactic and tartaric acids and gluconolactone (an internal ester of gluconic acid) - showed that the last two compounds, which are also stronger antioxidants, have a more effective anti-inflammatory effect.

However, the antioxidant properties of isolated AHAs are not very pronounced. However, when AHA is combined with other antioxidants, there is a synergistic effect, due to which the overall antioxidant potential of the mixture is significantly increased. Washing And Livrea studied the antioxidant activity of glycolic acid paired with vitamin E and melatonin on model lipid bilayers and human skin homogenate. They found that in the presence of glycolic acid, the antioxidant activity of vitamin E increases by 2.5 times, and melatonin by 1.8 times. The role of glycolic acid, apparently, is reduced to the restoration of the second component, as a result of which its antioxidant potential increases.

Increased synthesis of collagen and glycosaminoglycans

There is still no definitive clarity on how AHAs smooth out fine lines. One of the aspects of their action is the stimulation of fibroblast proliferation and activation of the synthesis of collagen I, which is part of the intercellular substance of the dermis. In addition, it has been shown that glycolic acid stimulates the biosynthesis of glycosaminoglycans, which are also part of the intercellular substance and participate in intercellular communication.

The effectiveness of action varies among different AHAs and is directly proportional to their dose. So, in experiments in vivo And in vitro Glycolic acid has been shown to have the strongest proliferative effect in the AHA series, followed by lactic and malic acids.

Under the action of AHA, the stratum corneum of the epidermis becomes thinner, while the dermis, on the contrary, thickens. As a result, small wrinkles are smoothed out, and large ones become less noticeable. Unfortunately, the amounts of AHA that our body produces are not enough to prevent the formation of wrinkles. Moreover, a-acetoxy acids are synthesized in the body (alpha acetoxy acids, AAA), which act in the opposite way to AHAs: they cause thickening of the epidermis and thinning of the dermis, and contribute to the formation of whiteheads and blackheads.

General approach to the development of AN A-cosmetics

A technologist working on the formulation of a cosmetic product with AHA solves several problems at the same time. First of all, it should be remembered that AHAs are substances with strong biological effects. With proper use of AHA cosmetics, the effect exceeds all expectations - the appearance of the skin improves significantly, however, if it is used uncontrollably and incorrectly, irreparable damage can be caused to the skin. In the case of AHA cosmetics, the line between safety and effectiveness is very narrow, and the product must be balanced so as to achieve maximum effectiveness with minimal risk. On the other hand, the developer faces a difficult technological task - to create a product that is stable at low pH values.

ChoiceAHA

AHAs used in cosmetology can contain up to 14 carbon atoms in their molecule. Depending on the molecular weight and structure of the hydrocarbon chain, which can be linear or branched, saturated or unsaturated, contain a different number of carboxyl and hydroxyl groups, have other active groups (amino, keto, thio groups), this AHA may be superior to other AHA or on the contrary, yield to them in the manifestation of certain properties.

The biological activity of AHA also depends on the configuration of the molecule. For example, in the case of lactic acid, only the L-isomer is effective, while the D-isomer does not have any pronounced effect on the skin.

Often, not one, but a mixture of several different acids is introduced into the recipe. For example, many AHA products combine glycolic acid with fruit acids. IN Lately products containing a mixture are becoming popular A- and P-hydroxy acids (so-called AHA/BHA products). It is believed that AHAs have a more pronounced exfoliating effect, and BHA - a stronger proliferative effect.

Among the AHAs approved for use in cosmetics are the following: glycolic, lactic, malic, citric, and tartaric. Salicylic acid can be named among VNA, although it is not typical from a chemical point of view. An American chemical company has been working in this direction for several years now. Inolex, which has developed several options for polyester carriers for various hydrophilic and lipophilic biologically active substances, including AHAs and UV filters. Polyester components with different structure, different molecular weight and solubility are selected taking into account the chemical characteristics of the delivered agent. They have the ability to penetrate the barrier of the stratum corneum without disturbing its structure, and gradually release the active ingredient already in the deeper layers of the skin.

Work on the creation of an effective controlled system for the delivery of AHA to the deep layers of the skin is carried out not only in scientific centers manufacturing companies, but also in independent laboratories. Recently in International Journal of Pharmacology interesting results obtained by Italian scientists from the Department of Pharmaceutical Chemistry of the University of Pavia were published. Studying the problem of liposomal delivery of glycolic acid, they selected the optimal parameters of the system, which allows delivering glycolic acid to the skin efficiently and without side reactions. They investigated various types of microcapsule carriers: liposomes, liposomes modified with chitosan, and chitosan microspheres. Liposomes consisting of phosphatidylcholine and cholesterol (molar ratio 1:1) were prepared by the standard reverse phase method. Chitosan was added to the lipid bilayer at the stage of preparation of liposomes or coated with ready-made liposomes. Microcapsules were studied using an electron microscope; their size was controlled by the light scattering method. To assess the ability of microparticles to modulate the release of glycolic acid, special dissolution tests have been developed. in vitro. The results obtained showed that liposomes can modulate the release of glycolic acid, and the optimal condition for this is a glycolic acid/lipid molar ratio of 5:1. Chitosan-added liposomes can also gradually release glycolic acid, while chitosan microparticles are not able to control the release of glycolic acid under any circumstances.

CombinationAHAwith other components

The exfoliating action of AHA facilitates the penetration of other biologically active substances that may be present in the preparation. Thus, AHA formulations often include antioxidants (for example, vitamins C and E) and plant extracts with various properties.

(anti-inflammatory, moisturizing, sedative). Formulas designed for pigmented skin include whitening agents such as hydroquinone or kojic acid. AHA preparations also contain such biologically active components as hyaluronic acid, pyrrolidonecarboxylic acids, squalene, peptides and amino acids, urea, phytoestrogens, the effectiveness of which increases in the presence of AHA.

Emollients are essential components in AHA preparations. Without having any biological effect, emollients nevertheless perform a very important function - they temporarily soften and protect the surface of the skin that has undergone peeling. Among the emollients that make up AHA preparations, both natural and synthetic compounds are used.

Conclusion

After treatment with AHA preparations, the skin becomes firmer and more elastic, the number of fine wrinkles and the severity of deep wrinkles are noticeably reduced - the skin is smoothed and looks younger and fresher. Miraculous skin rejuvenation is associated with the diverse biological action of AHA. So, in the epidermis, AHAs activate the process of exfoliating dead cells and increase the degree of hydration. As part of the dermis, AHAs affect the synthesis of the main elements of the extracellular matrix - collagen and glycosaminoglycans. The anti-inflammatory effect of AHAs is due to their antioxidant properties and ability to influence inflammatory mediators. Although many aspects of AHA's mechanism of action are not fully understood, the overall picture is clear. It is the versatility of the action of AHA that determines the remarkable effect that is observed after a course of AHA therapy.

In the second part of our review, placed under the heading "Medicine", we will talk about the use of AHA in clinical practice and consider various options, in which the use of AHA is effective and justified.

Hydroxy acids (alcohol acids) are derivatives of carboxylic acids containing one, two or more hydroxyl groups in the radical connected to the carboxyl.

According to the nature of the radical, hydroxy acids are saturated and unsaturated, acyclic, cyclic or aromatic.

The following types of isomerism occur in hydroxy acids:

structural(radical chain isomerism, isomerism of the mutual position of carboxyl and hydroxyl);

optical(mirror) due to the presence of asymmetric carbon atoms.

The names of hydroxy acids are given by the name of the acid with the addition of "hydroxy" or "dioxi", etc. The trivial nomenclature is also widely used.

HO–CH 2 –COOH

glycolic (oxyacetic)

dairy (α-hydroxypropionic)

α-hydroxybutyric β-hydroxybutyric

(2-hydroxybutanoic) (3-hydroxybutaneic)

Chemical properties.

2. Alcoholic properties - reactions of hydrogen substitution of the hydroxy group, the formation of ethers and esters, the substitution of -OH for halogen, intramolecular dehydration, oxidation.

chloroacetic glycolic glyoxal

acid acid acid

a) HO–CH 2 –COOH + CH 3 OH HO–CH 2 –CO–O–CH 3 + H 2 O

ester of glycolic acid and methyl alcohol

b) NO-CH 2 -COOH + 2CH 3 OH CH 3 -O - CH 2 -COOSH 3 + 2H 2 O

glycolic methyl methyl ether

acid alcohol methoxyacetic acid

(full broadcast)

3. The ratio of hydroxy acids to heating - when heated, α-hydroxy acids split off water, forming a cyclic ester, built as an id of two molecules of α-hydroxy acids:

α-hydroxypropionic acid lactide

β-hydroxy acids under the same conditions easily lose water with the formation of unsaturated acids.

NO–CH 2 –CH 2 –COOH CH 2 \u003d CH - COOH

β-hydroxypropionic acrylic acid

γ-hydroxy acids can also lose a water molecule with the formation of intramolecular esters - lactones.

NO–CH 2 –CH 2 –CH 2 –COOH

γ-hydroxybutyric acid

γ-butyrolactone

Some hydroxy acids are obtained from natural products. So, lactic acid is obtained by lactic acid fermentation of sugary substances. Synthetic production methods are based on the following reactions:

1) Cl–CH 2 –COOH + HOH HO–CH 2 –COOH;

monochloroacetic glycolic

acid acid

2) CH 2 \u003d CH - COOH + HOH
NO-CH 2 -CH 2 -COOH.

acrylic acid β-hydroxypropionic acid

representatives of hydroxy acids.

Glycolic (hydroxyacetic) acid is a crystalline substance found in unripe fruits, beet juice, turnips and other plants. In industry, it is obtained by the reduction of oxalic acid. It is used for dyeing (calico printing).

Lactic acid (α-hydroxypropionic) - a thick liquid or low-melting crystalline mass. Lactic acid is formed in the process of lactic acid fermentation of sugars, under the action of lactic acid bacteria. Contained in fermented milk products, sauerkraut, silage. It is used in mordant dyeing, in leather production, in medicine.

Meat-lactic acid is found in the muscle juice of animals and meat extracts.

diatomic glyceric acid participates in the life processes of plants and animals.

Ascorbic acid (vitamin C) - a crystalline substance found in fresh fruits, lemons, black currants, fresh vegetables - cabbage, beans. Synthetically, vitamin C is obtained by oxidation of the polyhydric alcohol sorbitol.

α-ascorbic acid

Ascorbic acid is easily decomposed by atmospheric oxygen, especially when heated.

Acyclic two-and tribasic hydroxy acids.

Apple (hydroxysuccinic) acid (HOOS-CHOH-CH 2 -COOH) is a crystalline substance that is highly soluble in water; used in medicine, found in unripe rowan, barberry, rhubarb, grape juice, wine.

Wine (tartaric, dioxysuccinic) acid (HOOC–*CHOH–*CHOH–COOH) has 2 asymmetric carbon atoms and therefore has 4 optical isomers. Forms acidic potassium salts, which are poorly soluble in water and precipitate. Salt crystals can be observed in wine (tartar). The mixed potassium-sodium salt is called Rochelle salt. Salts of tartaric acid are called tartrates.

tartar, rochelle salt

Tartaric acid is common in plants (mountain ash, grapes, etc.).

Lemon acid
found in citrus fruits. In industry, it is obtained from lemon fruits, by the oxidation of sugars by mold fungi, during the processing of spruce needles.

Citric acid is a biologically important compound that takes part in metabolism. It is used in medicine, food, textile industry as an additive to dyes.

Cyclic monobasic polyhydric hydroxy acids are part of bile acids and other physiologically important compounds; for example, auxin enhances plant growth.

Aromatic hydroxy acids subdivided into phenolic acids and aromatic fatty acids containing hydroxyl in the side chain.

o-hydroxybenzoic mandelic acid

(salicylic acid

aspirin salol (phenyl ether

(acetylsalicylic acid) salicylic acid)

Gallic acid (3,4,5-trioxybenzoic).

Contained in tea leaves, oak bark, pomegranate tree. In industry, it is obtained from tannin by boiling with dilute acids. It is used for the manufacture of ink, in photography, in medicine as an antiseptic. Gallic acid and its derivatives are widely used as preservatives for many food products (fats, high-grade soaps, dairy products), have tannic properties and are of some importance in the manufacture of leather and in stain dyeing.

mandelic acid refers to aromatic fatty acids (C 6 H 5 -CH (OH) -COOH), is found in amygdalin, mustard, elderberry, etc.

Tannins are often derivatives of polyhydric phenols. They are part of plants and are obtained from extracts of bark, wood, leaves, roots, fruits or growths (galls).

Tannins are the most important tannins. This is a mixture of various chemical compounds, the main of which are esters of gallic and digallic acids and glucose or polyhydric alcohols.

Dg-digallic acid

m-digallic acid

Lipids include organic substances, many of which are esters of macromolecular fatty acids and polyhydric alcohols - these are fats, phosphatides, waxes, steroids, macromolecular fatty acids, etc.

Lipids are found mainly in plant seeds, nut kernels, and in animal organisms - in adipose and nervous tissues, especially in the brain of animals and humans.

Natural fats are mixtures of esters of the trihydric alcohol glycerol and higher carboxylic acids, i.e. mixtures of glycerides of these acids.

ABOUT General formula for fat:

where R I R II R III are hydrocarbon radicals of higher fatty acids of a normal structure with an even number of carbon atoms. Fats can contain residues of both saturated and unsaturated acids.

Saturated acids:

С 15 H 31 COOH– palmitic;

C 17 H 35 COOH - stearic;

C 3 H 7 COOH - oil (contained in butter), etc.

Unsaturated acids:

C 17 H 33 COOH - oleic;

C 17 H 31 COOH - linoleic;

C 17 H 29 COOH - linolenic, etc.

Get fats from natural sources of animal and vegetable origin.

Physical Properties fats are acidic. Fats containing predominantly saturated acid residues are solid or ointment-like substances (mutton, beef fat, etc.). Fats, which contain mainly unsaturated acid residues, have a liquid consistency at room temperature and are called oils. Fats do not dissolve in water, but dissolve well in organic solvents: ether, benzene, chloroform, etc.

Chemical properties. Like all esters, fats undergo hydrolysis. Hydrolysis can proceed in an acidic, neutral or alkaline environment.

1. Acid hydrolysis.

Glycolic acid (hydroxyacetic acid, hydroxyethanoic acid) is an organic compound with the chemical formula C 2 H 4 O 3 , the simplest hydroxy acid. Colorless crystals with the smell of burnt sugar.

Application

Glycolic acid is used in various fields:

in organic synthesis
in industry - equipment cleaning
in the processing of metals (in particular, etching)
in the leather industry
in the oil and gas industry
in economic activities - as part of cleaning products
in cosmetology: as a keratolytic in chemical peeling of the skin, in the treatment of hyperkeratosis
as a natural exfoliant, cleanses the sebaceous ducts from comedones (acne), promotes the penetration of other active substances into the skin,
in the production of absorbable suture materials for surgical operations: Dexon and Polyglactin-910.

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Literature

O. Ya. Neiland. Organic chemistry. - M .: Higher School, 1990. - 751 p. - 35,000 copies. - ISBN 5-06-001471-1.

An excerpt characterizing Glycolic acid

“God have mercy, you never need a doctor,” she said. Suddenly a gust of wind blew on one of the exposed frames of the room (by the prince’s will, one frame was always set up with larks in each room) and, having beaten off the poorly pushed bolt, ruffled the damask curtain, and smelling of cold, snow, blew out the candle. Princess Mary shuddered; the nanny, putting down her stocking, went up to the window, and leaning out began to catch the open frame. A cold wind ruffled the ends of her handkerchief and gray, stray strands of hair.
- Princess, mother, someone is driving along the prefecture! she said, holding the frame and not closing it. - With lanterns, it must be, dokhtur ...
- Oh my god! God bless! - said Princess Mary, - we must go to meet him: he does not know Russian.
Princess Marya threw on her shawl and ran to meet the travelers. When she passed the front hall, she saw through the window that some kind of carriage and lamps were standing at the entrance. She went out onto the stairs. A tallow candle stood on the railing post and flowed from the wind. The waiter Philip, with a frightened face and with another candle in his hand, was standing below, on the first landing of the stairs. Even lower, around the bend, on the stairs, steps could be heard moving in warm boots. And some kind of familiar voice, as it seemed to Princess Mary, was saying something.
- God bless! said the voice. - And the father?
“Go to sleep,” answered the voice of the butler Demyan, who was already downstairs.
Then a voice said something else, Demyan answered something, and steps in warm boots began to approach faster along an invisible turn of the stairs. "This is Andrey! thought Princess Mary. No, it can’t be, it would be too unusual, ”she thought, and at the same moment as she thought this, on the platform on which the waiter was standing with a candle, the face and figure of Prince Andrei in a fur coat with a collar sprinkled with snow. Yes, it was him, but pale and thin, and with a changed, strangely softened, but anxious expression on his face. He entered the stairs and hugged his sister.

Glycolic acid is an organic compound related to fruit acids. It is usually obtained from green grapes or sugar cane. It can also be synthesized artificially. Glycolic acid is denoted by the formula C2H4O3 and has a number of unique properties allowing to use it in various cosmetic procedures.

The compound is also found in many skin care products. Its high regenerative ability is noted. It not only cleanses the skin of the upper, dead layer, but also starts the process of renewal of dermal cells. After cleansing the epidermis, the skin is evened out, and its color and texture are improved.

Properties and functions

Useful cosmetic properties of glycolic acid are determined by its ability to easily penetrate into the upper layers of the skin and dissolve dead particles. It stimulates the mechanism of cellular renewal and activates the formation of collagen fibers, which help smooth wrinkles. As part of peeling products, glycolic acid helps to remove age spots and freckles. Organic acid can perform the following functions:

acceleration of regeneration of epidermal cells;
cleaning the top layer of old cells;
removal of sebum and cleaning of pores;
normalization of activity of sweat glands;
removal or lightening of age spots and freckles;
stimulation of the synthesis of hyaluronic acid and collagen fibers;
wrinkle smoothing.

Mechanism of action on the skin

Glycolic acid dissolves the components that stick together skin scales. As a result, the process of their exfoliation is accelerated. After the removal of dead particles, the mouths of the hair follicles are released, and the release of sebum is facilitated. The acidic environment activates cell regeneration, as a result of which the skin is renewed and becomes young and fresh. At the same time, the production of collagen, elastin and hyaluronic acid is stimulated in fibroblasts. The skin becomes softer and more elastic, while the tone increases and its alignment and smoothing of wrinkles occur. You can learn about masks with acids.

The drug has an anti-inflammatory and antioxidant effect on the points of application. The acidic environment destroys the coloring pigment melanin, which makes the spots on the face less noticeable, up to their complete discoloration.

Indications for use and benefits

This organic compound and preparations based on it can be used by all age categories of women. The effect is especially noticeable in middle-aged women with oily skin. In girls during puberty, the skin is especially sensitive and acne (acne) and pustular rashes often occur on the face, associated with hormonal changes in the body. Therefore, preparations and procedures with glycolic acid can be prescribed to girls from the age of 16. The main indications for cosmetic procedures with glycolic acid can be as follows:

problematic skin with blackheads;
enlarged pores;
acne;
aging skin;
small defects;
age pigmentation;
freckles.

In persons constantly exposed to ultraviolet radiation, negative changes in the dermis occur on exposed parts of the body, especially on the face. This process is called photoaging. The use of drugs with acid will significantly reduce the effects sunburn. Learn how to make a vitamin C mask at home at.

Contraindications and complications

Glycolic acid is a mild chemical, but there are still contraindications:

especially sensitive skin;
individual intolerance;
the presence of warts and neoplasms on problem areas;
herpes;
mechanical damage;
bacterial inflammatory process.

Regarding the use of glycolic acid during pregnancy and lactation, doctors disagree. The best option for expectant mothers would be a consultation with a dermatologist. Negative complications can occur in women with swarthy skin. The use of drugs can cause hyperpigmentation. The use of acid is not recommended for those who take retinoids (vitamin A), as these drugs increase the effect of chemical exposure.

Application in cosmetology

The widespread use of glycolic acid in cosmetology is due not only to high preventive and medicinal properties but also the low cost of the drug. Glycolic acid gives a complex anti-aging effect due to keratolytic, exfoliating and cleansing properties. If this compound is part of other drugs, then it allows you to deeply penetrate into the dermis, acting as a conductor.

The effect of cosmetic products with glycolic acid

Preparations with this acid brighten the skin and promote the synthesis of collagen fibers. The substance can be used to prevent wrinkles and reduce the defects of aging skin. Collagen fibers make the skin more elastic, which reduces the possibility of wrinkles and partially smoothes existing ones. Contributes to the narrowing of pores, which allows you to get rid of comedones and regulate the process of the appearance of sebum. A noticeable positive effect was noted when caring for damaged or diseased hair. It gives shine, restores the structure of the hair and eliminates possible itching and dandruff. Find out which are the most effective collagen masks.

Funds with C2H4O3

It is included in the following cosmetic products:

peeling;
cream;
tonic;
mask;
cleansing gel;
cleansing milk.

Before using products with C2H4O3, you should consult with a beautician.

Peeling

Peeling products with glycolic acid have gained the greatest popularity in cosmetology:

Beauty Med peeling to eliminate rough wrinkles contains no more than 10% fruit acids, so it can be used independently at home. The drug evens out the complexion, tightens pores and helps to reduce mimic and age wrinkles.
Gel peeling "Pleyana" is considered a sparing drug due to the low content of glycolic acid. stimulates the production of collagen and gives a good lifting effect.
The Neopeel Glycolic high acid range is for professional use only. Self-guided procedures are not allowed.
Peeling cream Glico-A from the French company IRIS can be used at home. cleanses and tightens pores, normalizes the work of the sebaceous glands and allows you to fight the signs of aging on the face.

Creams

Cream Glycolic Acid with birch sap is a delicate treatment for problem areas of the body. In addition to the rejuvenating effect, this cosmetic product moisturizes and fortifies the skin.

Price: 900 rubles.

Source Naturals is a blend of herbal extracts and nutrients. The cream is intended for daily use in the evening.
anti-aging anti-aging cream Collistar with a pronounced tightening effect. suitable for middle-aged women and intended for daily use.
Reviva Labs cream easily penetrates the skin, limits the appearance of wrinkles and gives the face a healthy complexion.
Face cream A'PIEU Glycolic Acid Cream has no restrictions on skin type. It can be applied both in the morning and in the evening.
Avne Cleanance K Cream-Gel cleanses pores, removes dead cells, mattifies the face and moisturizes the dermis.
Guam anti-stretch mark cream for body and chest with glycolic acid is suitable for body care in postpartum period. The composition includes oils and scrub particles.

Emulsions and lotions

Lotions and emulsions with fruit acids are universal cosmetics. They can be used regardless of the time of year and age.

Academy Exfoliating Emulsion unclogs pores and smoothes out fine lines. Apply in the evening after removing make-up.

Price: about 4500 rubles.

Clinique Mild Clarifying Lotion removes old cells, moisturizes and soothes sensitive skin.

Peeling at home

Glycolic peeling at home is available to everyone. The process consists of several successive steps that must be strictly observed:

cleansing;
application;
neutralization;
completion of the procedure;
soothing care.

Before peeling yourself, you should consult a cosmetologist and if he does not find contraindications, you can proceed to the procedure. Before the procedure, you need to clean your face with lotion. This removes dirt and dead particles. If the dermis is very rough, then two weeks before the procedure, the face should be treated with a cream containing fruit acids.

When performing the procedure, you must follow a certain sequence. The forehead is treated first, then the nose and cheeks, and lastly the chin. The first application should not exceed 2-3 minutes. Neutralization consists in treating the face with a special composition that has an alkaline reaction. After neutralization, you can wash your face with a decoction of chamomile or calendula. Within 2-3 days, you can not use decorative cosmetics, and softening and moisturizing creams should be applied to problem areas. Find out what gas-liquid peeling is.

The cost of glycol peeling in the salon

The procedure carried out in the salon includes superficial, median and deep peeling. Depending on this, as well as on the level of service, the cost of one procedure can vary from 1,000 to 5,000 rubles. Meso-peeling involves a deep effect on the dermis, while the active substances are injected by injection to a depth of 1-2 mm. One procedure will cost the client in the amount of 1,500 to 2,000 rubles.

Video

Conclusion

Chemical is a gentle technique and can be performed at home.
Glycolic acid is a highly effective skin care agent and promotes its rejuvenation.
Acid is a mild chemical, but there are still contraindications. During pregnancy and lactation, before use, you should consult a specialist.
When performing the procedure with glycolic acid at home, you need to follow a certain sequence. The forehead is treated first, then the nose and cheeks, and lastly the chin.