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. (8, 12)
belongs to the class of organic compounds known as c-nitro compounds. C-nitro compounds are compounds having the nitro group, -NO2 (free valence on nitrogen), which is attached to carbon.
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. These decomposition products can react with any secondary amines or amides (which may contaminate cosmetic products) to produce significant levels of nitrosamines, which are believed to be carcinogenic. Once in the body, nitrosamines are activated by cytochrome P-450 enzymes. They are then believed to induce their carcinogenic effects by forming DNA adducts at the N- and O-atoms. Formaldehyde itself is also carcinogenic. It is likely that formaldehyde toxicity occurs when intracellular levels saturate formaldehyde dehydrogenase activity, allowing the unmetabolized intact molecule to exert its effects. Formaldehyde is known to form cross links between protein and DNA and undergo metabolic incorporation into macromolecules (DNA, RNA, and proteins). (9, 8, 10, 3, 4, 5, 6, 12)
Metabolism
Nitrosamines can enter the body via ingestion, inhalation, or dermal contact. Once in the body, nitrosamines are metabolized by cytochrome P-450 enzymes, which essentially activates them into carcinogens. Sarcosine is metabolized to glycine by the enzyme sarcosine dehydrogenase. Formaldehyde may be absorbed following inhalation, oral, or dermal exposure. It is an essential metabolic intermediate in all cells and is produced during the normal metabolism of serine, glycine, methionine, and choline and also by the demethylation of N-, S-, and O-methyl compounds. Exogenous formaldehyde is metabolized to formate by the enzyme formaldehyde dehydrogenase at the initial site of contact. After oxidation of formaldehyde to formate, the carbon atom is further oxidized to carbon dioxide or incorporated into purines, thymidine, and amino acids via tetrahydrofolatedependent one-carbon biosynthetic pathways. Formaldehyde is not stored in the body and is excreted in the urine (primarily as formic acid), incorporated into other cellular molecules, or exhaled as carbon dioxide. (3, 4, 11, 9)
No indication of carcinogenicity (not listed by IARC). (7)
Uses/Sources
Bronopol 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. (8)
Minimum Risk Level
Not Available
Health Effects
Bronopol may react to produce nitrosamines, which are believed to be carcinogenic. It also releases formaldehyde, a known human carcinogen. (9, 6)
Symptoms
Not Available
Treatment
EYES: irrigate opened eyes for several minutes under running water.
INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice.
SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention.
INHALATION: supply fresh air. If required provide artificial respiration.
