BRONOPOL
BRONOPOL
Bronopol is a single active ingredient and suitable for leave-on, rinse-off and wet wipes applications.
Product benefits include excellent bactericidal effect and strong activity against gram-negative bacteria (Pseudomonas sp.).
This crystalline powder is a powerful preservative even at low use levels and suitable for a neutral pH rinse-off application.
Bronopol (2-bromo-2-nitropropane-1,3-diol) is a very cost-effective preservative for a broad range of cosmetic products, requiring very low in-use concentrations.
The high water solubility makes it easy to use in cosmetic and detergent formulations.
FEATURES OF BRONOPOL
Cost effective preservative for a broad range of cosmetic products, requiring very low in-use concentrations
High water solubility makes it easy to use
Especially active against bacteria
Low in-use concentration and the relatively high irritation threshold level makes Bronopol an ideal preservative for delicate skin
Bronopol is a preservative and antiseptic used in cosmetics and topical medications. It is used as a preservative in paints, textiles, cooling towers, humidifiers, and hide processing.
Bronopol is used in cleaning agents, paints, cosmetics, glues, paper mills, water systems, metalworking fluids, polishes, and printing inks.
2-Bromo-2-nitropropane-1,3-diol; 2-Nitro-2-bromo-1,3-propanediol; Bronidiol; Bronocot; Bronopol; Bronopolu [Polish]; Bronopolum [INN-Latin]; Bronosol; Bronotak; Lexgard bronopol; Onyxide 500; beta-Bromo-beta-nitrotrimethyleneglycol;
Bronopol (Bronopol), chemical name: 2-bromo-2-nitro-1,3-propylene glycol, claims again Bronopol, bromine nitre propyl alcohol, antibacterial alcohol, Pi Lebao etc.
Bronopol be a kind of white to light yellow crystalline powder, 120～123 DEG C of fusing points, soluble in water, ethanol, propylene glycol, be insoluble in chloroform, acetone, benzene etc.Bronopol is a kind of wide spectrum, efficient, hypotoxicity fungicidal preservative, within the scope of wider pH, brings into play anti-microbial activity, and yeast, mould are had to good restraining effect, and gram-positive microorganism, negative bacterium inhibition that special antagonism is strong are outstanding.Because it still can keep its germ resistance in positively charged ion, nonionogenic tenside and protein solution thing, very suitablely in shampoo, shampoo, whipping agent, make mould inhibitor, therefore be widely used in makeup, massfraction in makeup is 0.01wt%～0.02wt%, in global cosmetics preservative usage frequency statistics in 2003, is ranked first 8.
Bronopol can be prevented and treated because the black arm of the caused cotton of cabbage black rot Flavobacterium is sick or bacillary carving rot as cotton seeds treatment agent.
Along with the continuous expansion of Application Areas, in the industries such as paper industry, water treatment, coating, washing composition, shoe polish, oil field, be widely used as sterilization, mildew-resistant and algicide.
External very active to the research of bronopol synthetic method, in view of the huge market demand of China, more domestic units were also studied it in recent years, and attempted to explore good suitability for industrialized production route.
Bronopol is a chemical compound of bromine and an antimicrobial substance. It is used as a preservative in pharmaceuticals, as well as numerous consumer products such as shampoos and cosmetics. It is also used as an antimicrobial in many industrial environments such as paper mills, oil exploration and production facilities, as well as cooling water disinfection plants. Its use is declining due to its recognized potential to decompose into carcinogenic nitrosamines.
It is also a formaldehyde releaser.
Bronopol (INN; chemical name 2-bromo-2-nitro-1,3-propanediol) is an organic compound that is used as an antimicrobial.
It is a white solid although commercial samples appear yellow.
CAS Registry Number: 52-51-7
Bronopol is used in consumer products as an effective preservative agent, as well as a wide variety of industrial applications (almost any industrial water system is a potential environment for bacterial growth, leading to slime and corrosion problems – in many of these systems Bronopol can be a highly effective treatment).
It is also used as a substitute for Formaldehyde in chemical toilets.
The use of Bronopol in personal care products (cosmetics, toiletries) has declined since the late 1980s due to the recognized potential for nitrosamine formation.
Bronopol is used as a preservative in various cosmetic, toiletry and household preparations particularly because of its high activity against Gram-negative bacteria, especially Pseudomonas aeruginosa and other pseudomonads.
These organisms are common residents in water and as such can cause contamination and spoilage problems in cosmetics and toiletties.
Pseudomonads are frequently implicated, particularly in oil-in-water emulsions which contain a significant amount of nonionic surfactants.
Bronopol is an effective antibacterial preservative over a wide pH range.
It is stable at acid pH’s and is also useful as a labile antibacterial preservative in alkaline media.
Because of its broad-spectrum antibacterial activity Bronopol can also be used as an active agent, for example, in aerosol formulations.
Bronopol has been reported to show persistent activity on the skin by Marples and Kligman, this contrasts with the fact that in vitro it has been shown to have a weak growth-inhibitory effect on cultured human skin cells by Onoda and Saito.
2-Bromo-1-nitro-1,3-propanediol
2-Bromo-2-nitro-1, 3-propanediol
2-Bromo-2-nitro-1,3-propanediol
2-Bromo-2-nitropropan-1,3-diol
2-Bromo-2-nitropropane-1,3-diol
2-Nitro-2-bromo-1, 3-propanediol
2-Nitro-2-bromo-1,3-propanediol
b-bromo-b-nitrotrimethyleneglycol
Beta-bromo-beta-nitrotrimethyleneglycol
Bioban BNPD-40
• 2-Bromo-2-nitropropane-1,3-diol
• 2-Nitro-2-bromo-1,3-propanediol
• Bronidiol
• Bronocot
• Bronopol
• Bronosol
• Bronotak
• HSDB 7195
• Lexgard bronopol
• NSC 141021
• Onyxide 500
• beta-Bromo-beta-nitrotrimethyleneglycol Germall® 11
Bronopol is an antimicrobial agent used, inter alia, in the cosmetic industry and in the treatment of industrial waste water.
Bronopol is an antimicrobial agent commonly used as a preservative in many types of cosmetics, personal care products, and topical medications.
It is used as an anti-infective, an antimicrobial, fungicide, germicide, bactericide,slimicide, and a wood preservative.
It is reportedly very effective against grampositive and gram-negative bacteria, particularly Pseudomonas aeruginosa as well as against fungi and yeasts.
This substance may release formaldehyde and cross-reacts with other formaldehyde-releasing substances.
• 2-Bromo-2-nitropropane-1,3-diol
• 2-Nitro-2-bromo-1,3-propanediol
• Bronidiol
• Bronocot
• Bronopol
• Bronosol
• Bronotak
• HSDB 7195
• Lexgard bronopol
• NSC 141021
• Onyxide 500
• beta-Bromo-beta-nitrotrimethyleneglycol Germall® 11
Bronopol (INN) is a highly active antimicrobial chemical compound whose chemical formula is 2-bromo-2-nitropropane-1,3-diol.
Bronopol is an effective antimicrobial in many industrial environments such as paper mills, oil exploration and production facilities, as well as cooling water disinfection plants.
Bronopol (INN) is a highly active antimicrobial chemical compound whose chemical formula is 2-bromo-2-nitropropane-1,3-diol.
Bronopol is an effective antimicrobial in many industrial environments such as paper mills, oil exploration and production facilities, as well as cooling water disinfection plants.
The global bronopol market grew at a CAGR of 6.5% during 2014-2019. Bronopol is a colorless, water-soluble organic compound, produced by the bromination of di(hydroxymethyl)-nitromethane.
It is supplied as crystals or crystalline powder, which is usually available in the shades of white and pale yellow, depending on the grade of iron content.
It is highly active against bacteria, fungi and yeasts and has high purity and tensile strength. Its biocidal uses include disinfection, product preservation, along with the preservation of fibers, leather and rubber.
Due to its antimicrobial properties, it is extensively used for manufacturing medicines, cosmetics and personal care products such as lotions, makeup, perfumes and shampoos
Increasing demand for drinkable water across the globe is the key factor driving the growth of the market.
Bronopol is widely used in several water treatment plants to meet this ever-increasing demand as it kills various types of bacteria present in the water and makes it fit for drinking.
Since water forms an indispensable part of industrial and residential activities, it is further contributing to the product demand.
Moreover, industrial water systems are a potential environment for bacterial growth and bronopol assists in preventing contamination through corrosion and slime in industrial water recirculating plants.
Additionally, increasing health awareness among consumers regarding the diseases caused by water-borne pathogens and bacterial growth is catalyzing the market growth.
Also, rising activities in the oil and gas sector where bronopol is used to prevent corrosion due to bacterial contamination in hydraulic fracturing equipment are driving the product demand.
Bronopol was invented by The Boots Company PLC in the early 1960s and first applications were as a preservative for pharmaceuticals. Due to its low mammalian toxicity at in-use
levels and high activity against bacteria, especially Gram-negative species, bronopol became popular as a preservative in many consumer products such as shampoos and cosmetics.
It was subsequently adopted as an antimicrobial in other industrial environments such as paper mills, oil exploration, and production facilities, as well as cooling water disinfection
plants.
2-Bromo-2-nitropropane-1,3-diol
2-bromo-2-nitropropane-1,3-diol appears as white crystals. Ignite easily and burn readily. May detonate under strong shock. Decomposes when heated, evolving toxic gases. Toxic by skin
absorption, inhalation or ingestion.
Bronopol, or 2-Bromo-2-nitro-1,3-propanediol, is an organic compound with wide-spectrum antimicrobial properties. First synthesized in 1897, bronopol was primarily used as a
preservative for pharmaceuticals and was registered in the United States in 1984 for use in industrial bactericides, slimicides and preservatives. Bronopol is used as a microbicide
or microbiostat in various commercial and industrial applications, including oil field systems, air washer systems, air conditioning or humidifying systems, cooling water systems,
papermills, absorbent clays, metal working fluids, printing inks, paints, adhesives and consumer products. Compared to other aliphatic halogen-nitro compounds, bronopol is more stable
to hydrolysis in aqueous media under normal conditions. The inhibitory activity against various bacteria, including Pseudomonas aeruginosa, was demonstrated in vitro. The agent is
largely available commercially as an antibacterial for a variety of industrial purposes while it is predominantly available for purchase as a pet animal litter antibacterial at the
domestic consumer level. Nevertheless, ongoing contemporary re-evaluations of bronopol use in large markets such as Canada now place various compositional and product restrictions
on the use of the agent in cosmetic products and in other products where it may not primarily be used in the role of a non-medicinal preservative antimicrobial.
Bronopol is produced by the bromination of di(hydroxymethyl)nitromethane, which is derived from nitromethane by a nitroaldol reaction.World production increased from the tens
of tonnes in the late 1970s to current estimates in excess of 5,000 tonnes. Manufacturing today is the business of low cost producers, mainly in China.
Applications
Bronopol is used in consumer products as an effective preservative agent, as well as a wide variety of industrial applications (almost any industrial water system is a potential
environment for bacterial growth, leading to slime and corrosion problems – in many of these systems bronopol can be a highly effective treatment).
The use of bronopol in personal care products (cosmetics, toiletries) has declined since the late 1980s due to the potential formation of nitrosamines. While bronopol is not in itself
a nitrosating agent, under conditions where it decomposes (alkaline solution and/or elevated temperatures) it can liberate nitrite and low levels of formaldehyde and these decomposition
products can react with any contaminant secondary amines or amides in a personal care formulation to produce significant levels of nitrosamines (due to the toxicity of these substances,
the term ‘significant’ means levels as low as 10s of parts per billion).
Manufacturers of personal care products are therefore instructed by regulatory authorities to avoid the formation of nitrosamines which might mean removing amines or amides from the
formulation, removing bronopol from a formulation, or using nitrosamine inhibitors.
Bronopol has been restricted for use in cosmetics in Canada.
Physical and chemical properties
Appearance
Bronopol is supplied as crystals or crystalline powder, which may vary from white to pale yellow in colour depending on the grade. The yellow coloration is due to chelation of iron
during the manufacturing process.
Melting point
As a pure material, bronopol has a melting point of about 130 °C. However, due to its polymorphic characteristics, bronopol undergoes a lattice rearrangement at 100 to 105 °C and this
can often be wrongly interpreted as the melting point.
At temperatures above 140 °C, bronopol decomposes exothermically releasing hydrogen bromide and oxides of nitrogen.
Solubility
Bronopol is readily soluble in water; the dissolution process is endothermic. Solutions containing up to 28% w/v are possible at ambient temperature.
Bronopol is poorly soluble in non-polar solvents but shows a high affinity for polar organic solvents.
Solubilities at 22–25 °C
Solvent %w/v
Water 28
Methanol 89
Ethanol 56
Isopropanol 41
Liquid Paraffin <0.5
Partition coefficient
Study of the solubility data shows that bronopol has a high affinity for polar rather than non-polar environments. In two-phase systems, bronopol partitions preferentially into
the polar (usually aqueous) phase.
Partition coefficients at 22–24 °C
Solvent Combination Partition Co-efficient
Hexanol/Water 0.74
Alkane|Liquid Paraffin/Water 0.043
Chloroform/Water 0.068
Stability in aqueous solution
In aqueous solutions, bronopol is most stable when the pH of the system is on the acid side of neutral. Temperature also has a significant effect on stability in alkaline systems.
Degradation
Under extreme alkaline conditions, bronopol decomposes in aqueous solution and very low levels of formaldehyde are produced. Liberated formaldehyde is not responsible for the
biological activity associated with bronopol. Other decomposition products detected after bronopol breakdown are bromide ion, nitrite ion, bromonitroethanol and
2-hydroxymethyl-2-nitropropane-1,3-diol.
Allergy
Patch test
In 2005–2006, it was the 15th-most-prevalent allergen in patch tests (3.4%) of people with suspected allergic contact dermatitis. It is used as a substitute for formaldehyde,
a disinfectant and preservative, in solvents. It is prevalent in skin and personal care products and topical medications.
1,3-Propanediol, 2-bromo-2-nitro-
2-Bromo-2-nitro-1,3-propanediol
2-Nitro-2-bromo-1,3-propanediol
beta-Bromo-beta-nitrotrimethyleneglycol
Bronidiol
Bronocot
Bronopolu
Bronopolum
Bronosol
Bronotak
Lexgard bronopol
Onyxide 500
Translated names
2-brom-2-nitropropan-1,3-diol (cs)
2-brom-2-nitropropan-1,3-diolis (lt)
2-brom-2-nitropropān-1,3-diols (lv)
2-Brom-2-nitroropan-1,3-diol (de)
2-Bromi-2-nitropropaani-1,3-dioli (fi)
2-bromo-2-nitropropaan-1,3-diool (et)
2-bromo-2-nitropropan-1,3-diol (hr)
2-bromo-2-nitropropan-1,3-diolo (it)
2-bromo-2-nitropropane-1,3-diol (fr)
2-bromo-2-nitropropano-1,3-diol (es)
2-broom-2-nitropropaan-1,3-diol (nl)
2-bróm-2-nitropropán-1,3-diol (hu)
2-βρωμο-2-νιτρο-προπανο-1,3-διόλη (el)
2-бромо-2-нитропропан-1,3-диол (bg)
bronopol (cs)
bronopol (DCI) (es)
bronopol (INN) (cs)
bronopol (INN); 2-bromo-2-nitropropane-1,3-diol (fr)
Bronopoli (fi)
Bronopoli (INN) (fi)
Bronopolis (lt)
bronopolis (INN) (lt)
Bronopols (lv)
bronopols (INN) (lv)
Bronopool (et)
bronopool (INN) (et)
Бронопол (bg)
Biocidal active substances
бронопол (INN) (bg)
IUPAC names
2 bromo-2-nitropropane-1,3-diol
2-Brom-2-Nitropropane-1,3-Diol
2-bromo-2-nitro-1,3-propanediolbronopol
2-bromo-2-nitro-propane-1,3-diol
2-bromo-2-nitropropane-
2-bromo-2-nitropropane-1,3-diol bronopol (INN)
2-bromo-2nitropropane-1,3-diol
BromnitropropandiolBronopolRD_CLP_52-51-7_1,3-Propanediol, 2-bromo-2-nitro-_V1_20180110_TS
Morpholin-4-yl morpholine-4-carbodithioate
Trade names
2-Bromo-2-nitropropane-1,3-diol (chemical name)
BNPD
Bronopol (common name)
Bronopol strongly inhibits the growth of Gram positive and Gram negative Bacteria.
It also is highly effective in eliminating the growth of Pseudomonas species, including pathogenic Pseudomonas aeruginosa.
Its applications include cosmetic, pharmaceutical, toiletry and household products.
When the control of yeasts and molds is required, Bronopol can be combined with other antimicrobials that provide additional anti-fungicidal activity.
Blends of Bronopol and Parabens give excellent coverage of all microbial spectra.
High compatibility with cationic, nonionic, anionic and amphotericsurfactants and many other raw materials, including other preservatives,makes Bronopol a very versatile product.
It is soluble in water and other polar solvents such as propylene glycol and isopropanol.
We recommend adding Bronopol to aqueous phase as it will prevent the primary bacterial growth that takes place in this medium.
Bronopol breaks down under alkaline conditions and elevated temperatures and should not be used in combination with secondary amines.
This can lead to an undesired chemical reaction and formation of nitrosamines.
For coldprocess products, we recommend adding Bronopol from the onset of the formulation preparation process.
The recommended use level for Bronopol ranges from 0.03% to 0.1%.
BRONOPOL
MINIMUM INHIBITION CONCENTRATIONS (MIC) FOR BRONOPOL
Microorganism Type MIC (ppm)
Escherichia coli Bacteria Gram – 15
Pseudomonas aeruginosa Bacteria Gram – 15
Burkholderia cepacia Bacteria Gram – 15
Staphylococcus aureus Bacteria Gram + 10
Staphylococcus epidermidis Bacteria Gram + 15
Aspergillus niger Mold 2000
Candida albicans Yeast 1250
Other names: 1,3-Propanediol, 2-bromo-2-nitro-; Bronocot; Onyxide 500; 2-Bromo-2-nitro-1,3-propanediol; 2-Bromo-2-nitropropane-1,3-diol; Bronosol; 2-Nitro-2-bromo-1,3-propanediol;
2-Bromo-2-nitropropan-1,3-diol; β-Bromo-β-nitrotrimethyleneglycol; Bronopolu; Bronotak; Bioban; Bronidiol; Canguard 409; Lexgard bronopol; Myacide AS plus; Myacide BT; NSC 141021;
Myacide Pharma BP
Bronopol
CAS number:52-51-7
Gross formula:C3H6BrNO4
Appearance:white or beige crystalline substance.
Chemical name and synonym:2-Bromo-2-nitro-1,3-propanediol, Bronopol.
Physical and chemical properties:
Molecular weight 199.99 g / mol
Melting point 124-129 ºC
Solubility in water 25 g / 100 ml (22 ºC)
Description:
Bronopol is a white, odorless crystalline substance that melts at about 130 ºC. It is readily soluble in water, lower alcohols, acetic acid, diethyl ether and ethyl acetate, but poorly soluble in chloroform, acetone and practically insoluble in hydrocarbon solvents. The values of the solubility of bronopol in some solvents are as follows (w / v% at 22-25 ° C): water 28; methyl alcohol 89; ethyl alcohol 56; isopropyl alcohol 41; ethylene glycol 61; methylcarbitol 54; 1,2-propylene glycol 52; dipropylene glycol 48; polyethylene glycol 300; diethyl sebacate 10; isopropyl myristate, mineral oil and vegetable oils less than 0.5. Aqueous solutions of a pure compound have a pH of 5.0-5.5, which is explained by the mobility of hydroxyl hydrogen atoms. Solid compound can be stored for 3 years or longer, it is not influenced by factors such as daylight, humidity (up to 90%) and temperature (up to 45 ° C). However, an aqueous solution of Bronopol is stable only in the cold, provided that the acidity is high enough. An increase in pH and temperature leads to the decomposition of the compound as a result of the decomposition of formaldehyde. The initial process of decomposition of bronopol appears to be a retroaldol reaction with the release of formaldehyde and the formation of bromonitroethanol.
Bromonitroethanol itself is significantly less stable than bronopol, and in the range of conditions studied, its maximum concentration did not exceed 0.5% of the initial concentrations of bronopol. At the same time, a second-order reaction occurs with the participation of bronopol and formaldehyde to obtain 2-hydroxymethyl-2-nitro-1,3-propanediol. The antimicrobial activity of bronopol is mainly due to the presence of electron-deficient bromine atoms in the molecules, which exhibit oxidizing properties, and not the ability to release formaldehyde. The mechanism of the antimicrobial action of bronopol consists of cross-linking of sulfhydride groups of dehydrogenase enzymes that occur on the surface of microbial cells. Disulfide bridges block the metabolism of microorganisms.
Application:
Bronopol is used as a preservative in various cosmetic and household products due to its high activity against gram-negative bacteria, especially Pseudomonas aeruginosa and other pseudomonads. These organisms are common water dwellers and can cause pollution and deterioration problems. Bronopol is an effective antibacterial preservative in a wide pH range. It is stable at acidic pH values and is also useful as a labile antibacterial preservative in an alkaline environment. Due to its broad spectrum antibacterial activity, Bronopol can also be used as an active agent, for example in aerosol preparations.
Receiving:
The method for producing bronopol includes loading the reaction vessel with water, bromopicrin, nitromethane and paraformaldehyde, gradually supplying the base to the reaction vessel with stirring, bringing the reaction to completion and separating bronopol from the aqueous reaction mixture.
Bronopol products are currently registered for use in oilfield systems, air purification systems, industrial water treatment systems, laboratory water baths, coatings, emulsions, air conditioning / humidification systems, pulp and paper industry systems, metalworking cutting fluids, and also consumer / institutional products.
Action on the body:
Bronopol (2-bromo-2-nitropropane-1,3-diol) is a bactericide with limited effectiveness against fungal organisms. It is active against Pseudomonas species and should be used at a pH of 5 to 8.8, below the application temperature of 45 ° C. Bronopol has a complex mechanism of action that attacks thiol groups in cells, suppressing respiration and cellular metabolism.
Research indicates that bronopol is a corrosive eye irritant and moderate to severe skin irritant in rabbits. The fate of the environment and the ecological consequences of the use of Bronopol are moderately highly toxic for estuarine / marine invertebrates; slightly toxic to marine fish; slightly toxic to birds with acute oral ingestion. However, no quantitative risk assessment has been carried out. The risk to the aquatic environment is being addressed under the NPDES permitting program by the Water Resources Authority. It is now required that labels on all products containing Bronopol meet NPDES requirements.
Toxicological data:
Acute toxicity:
LD50 oral – rat – 180 mg / kg
LD50 cutaneous – rat – 1.600 mg / kg
Oral (LD50): 270 mg / kg [Mouse].
Oral (LD50): 250 mg / kg [Dog].
Ecotoxicity:
Fish toxicity LC50 – Oncorhynchus mykiss (rainbow trout) – 20 mg / l – 96 h
Toxicity to Daphnia and other aquatic invertebrates.
EC50 – Daphnia magna (large daphnia) – 1.6 mg / l – 48 h
Very toxic to aquatic life.
Bacteria: Phytobacterium phosphoreum: EC50 = 0.41-0.90 mg / l; 5.15.30 minutes; Microtoxic test; 15 degrees Celsius.
Bronopol
Bronopol is a fairly popular broad-spectrum preservative, which allows it to be used in some formulations as the only preservative. It is effective at low concentrations; as a rule, dosages used in cosmetics are below the maximum allowable limit of 0.1%, established by law.
The mechanism of the antimicrobial action of bronopol is quite complex, and, as a rule, it is not associated with the release of formaldehyde. That is why it is considered that it is a mistake to classify this preservative as a typical formaldehyde donor. Nevertheless, it cannot be denied that formaldehyde is nevertheless formed during the decomposition of bronopol, and the presence of cross-sensitivity to bronopol with an established allergy to formaldehyde takes place. However, the release of formaldehyde does not occur at the same rate and in the same amount under different conditions.
The main factors affecting the destruction of bronopol are pH, sunlight and temperature. It was found that with the addition of citric acid, which lowers the pH, the decomposition of bronopol in aqueous solutions slows down, which is quite natural, and an increase in temperature and exposure to sunlight increases the rate of decomposition. These facts are taken into account when formulating recipes.
There are few quantitative data on the destruction of bronopol – much less than for typical formaldehyde donors, but they are still there; the highest concentration of formaldehyde in alkaline compounds, which is quite natural, but they are not so high as to cause concern or put a warning about the presence of formaldehyde in the marking. The pH range from 5 to 6 can be considered quite favorable for the preservative’s behavior and for the skin.
Bronopol, like other preservatives, can cause the development of symptoms of contact dermatitis, but in most cases it does not belong to the leaders, but rather an outsider. A different situation is observed only in case of serious skin diseases, such as chronic eczema or atopic dermatitis, in which the normal barrier function of the skin is disrupted, and the frequency of using special cosmetics designed to relieve symptoms is increased, which leads to an increased risk of developing sensitization. But the specificity of allergic reactions to bronopol is not due to formaldehyde, but to other products of its decay, such as 2-bromoethanol, 2-bromo-2-nitroethanol and bromonitromethane.
The connection between the use of bronopol in cosmetics and the potential for the formation of carcinogenic nitrosamines theoretically exists (and if the established precautions are not followed, it can be realized in practice), but for this, restrictions are introduced to minimize these risks [1]… Nitrosamines are found almost everywhere in the environment; moreover, they are formed in the human digestive tract as a result of the reaction between secondary amines or amides and nitrite ions. Bronopol itself is not a nitrosating agent, but under conditions under which it decomposes (alkaline environment and / or elevated temperature), it can release nitrite ions, potentially capable of producing nitrosamines – if anything, because for this reaction there is only nitrite is not enough. Accordingly, bronopol is not used where there is a risk of formation of nitrosamines, and cosmetic raw materials, which may contain trace amounts of secondary amines or amides, undergo thorough cleaning and strict control
Bronopol has been shown to possess awide spectrum of antibacterial activity.
Its activity against Gram-negative organisms, particularly Ps. aeruginosa, is greater than that of most other antibacterial and preservative agents.
Activity and safety of Bronopol
Bronopol is most stable under acid conditions, although it demonstrates high antibacterial activity over a wide pH range.
The mode of decomposition has been studied in detail, and a number of the decomposition products identified.
The assay methods described are capable of estimating Bronopol in many formulations at its normally used levels, the sensitivity of the methods is dependent upon the nature of the formulations; in certain cases levels as low as 5 ppm can be assayed.
Bronopol is generally used as a preservative in formulations at levels between 0.01 and 0.1 •o.
Animal toxicity studies and human patch tests have demonstrated the safety of Bronopol when used at these concentrations.
In particular, no evidence of human skin sensitisation has been obtained at these levels.
Bronopol has been shown to be an effective antibacterial agent in a range of formulations including shampoos, skin creams and sprays and bath products.
Many of the ingredients used in such products have been shown to have little or no effect on the antibacterial activity of Bronopol, although compounds containing sulphydryl groups are antagonistic to its activity.
Antimicrobial preservatives (as a bronopol) are widely used in cosmetics and toiletries to prevent the spoilage of products due to microbial contamination than can be presented in wastewaters and in sewage sludge and may inhibit the process of sludge anaerobic stabilization
Bronopol (2-bromo-2-nitropropan-1,3-diol) is a white odourless crystalline substance well soluble in water, lower alcohols, diethyl ether, ethylacetate and acetic acid.
Bronopol is used as preservative and antiseptic agent in liquid medication forms, cosmetic creams, gels and aerosols, deodorants, foot powders, liquid soap, shampoo, household detergents, cleaning pastes, polishing compounds, toilet water deodorants ect.
Bronopol is also used as a biocide in industrial processes, for example textiles, paper mills and cooling water systems.
Bronopol is toxic for a wide spectrum of microorganisms, including Gram-negative species, resistant to lots of antibacterial agents.
The antimicrobial behaviour of bronopol is caused by electron-deficient bromine atoms in the molecules, which have oxidation properties.
The antimicrobial mechanism of bronopol in the cross-linking of sulfohydrids of enzymes existing on the microbial cells surface.
Adaptation to bronopol is theoretically impossible because of its nonspecific mechanism.
The main advantage of bronopol is high antimicrobial activity combinated with relatively low toxic effect to hot-blooded animals.
Dissolution of bronopol in aqueous solution at warm temperature and higher pH may lead to release of formaldehyde that is converted into formic acid.
In aqueous solutions, bronopol rapidly degrades to many transformation products like 2-bromo-2-nitroethanol, bromonitromethane, tri(hydroxymethyl)nitromethane, nitromethane, 2-bromoethanol, formaldehyde ect. However, its antimicrobial behaviour is still acceptable.