Benzoyl peroxide

Absorption

In a sample of excised skin, 1.9% of a radiolabelled topical dose fully penetrates the skin, and 2.6% remains in the skin. The radiolabelled dose that fully penetrates the skin is recovered as benzoic acid, while the dose in the skin is approximately half benzoic acid and half benzoyl peroxide. 95.5% of a radiolabelled dose is not absorbed or metabolized after 8 hours.

Toxicity

Data regarding overdoses of benzoyl peroxide are not readily available. During an overdose patients may experience and increased risk or severity of adverse effects such as skin itching, burning, peeling, inflammation, and erythema.
The oral LD50 in rats is 490 mg/kg.

Description

Benzoyl Peroxide may affect workers in the electronics and plastics (epoxy resins and catalysts) industries, electricians, ceramic workers, dentists and dental technicians, laboratory technicians and bakers. As it was contained in candles, it also induced contact dermatitis in a sacristan. However, some positive tests are of unknown occupational relevance.

Description

Benzoyl peroxide is a bleaching agent commonly found in acne treatments, hair coloring, and teeth whitening products. On the skin, it forms benzoic acid and oxygen, but it is used in large volumes to initiate polymerization in expandable styrene and other resins.

Chemical properties

Benzoyl peroxide is an odorless, white, or colorless crystalline powder with a faint odor of benzaldehyde resulting from the interaction of benzoyl chloride and a cooled sodium peroxide solution. It is used in specified cheeses at 0.0002% of milk level. It is also used for the bleaching of flour, slowly decomposing to exert its full bleaching action, which results in whiter flour and bread. The major decomposition product of benzoyl peroxide in water was benzoic acid, but trace amounts of phenyl benzoate, phenol, and hydroxybenzoic acids were formed. When carbon-14 la- beled benzoyl peroxide was reacted with whey, the same compounds were produced.

The Uses of Benzoyl peroxide

Benzoyl Peroxide is a widely used organic compound of the peroxide family. It is used as a source offree radicals in many organic syntheses andto initiate polymerizations of styrene, vinylchloride, vinyl acetate, and acrylics; to curethermoset polyester resins and silicone rubbers;in medicine for treating acne; and forbleaching vegetable oil, cheese, flour, and fats.

The Uses of Benzoyl peroxide

A mixture of the SM (100 g, 497 mmol), NBS (88.5 g, 497 mmol), and AIBN (10 g, 50 mmol) in CCl4 (700 mL) was stirred at reflux for 12 h. The mixture was cooled to RT, diluted with H2O, and extracted with EtOAc. The org layer was separated, dried (Na2SO4), and concentrated. The residue was purified by silica gel flash chromatography to provide the product. [48 g, 42%]

Indications

Benzoyl peroxide is formulated with antibiotics such as erythromycin and clindamycin for the treatment of acne vulgaris. Benzoyl peroxide is formulated as a number of topical products for the treatment of acne. Benzoyl peroxide is also indicated in combination with tretinoin for the treatment of acne vulgaris in patients aged nine years and older. A triple-combination therapy including both clindamycin and adapalene is also available and indicated for the treatment of acne vulgaris in patients ≥12 years of age.
Topical benzoyl peroxide is also indicated for the treatment of inflammatory lesions of rosacea in adults.

Background

Benzoyl peroxide is a commonly used drug in topical treatments for acne. It has been formulated as products with either a single active ingredient, or with erythromycin, clindamycin, or adapalene. After administration, the peroxide bond is cleaved, allowing benzoyloxy radicals to nonspecifically interact with proteins. This treatment decreases keratin and sebum around follicles, as well as increasing turnover of epithelial cells.
Benzoyl peroxide, in combination with erythromycin, was granted FDA approval on 26 October 1984.

Indications

Benzoyl peroxide is a potent oxidizing agent that has both antimicrobial and comedolytic properties; its primary use is in treating acne vulgaris. It is converted in the skin to benzoic acid; clearance of absorbed drug is rapid, and no systemic toxicity has been observed. The major toxicities are irritation and contact allergy. Outgrowth of bacteria resistant to topical antibiotics used to treat acne can be reduced by the addition of benzoyl peroxide in combination products such as erythromycin (Benzamycin) and clindamycin (Benzaclin).

Definition

ChEBI: Benzoyl peroxide is a carbonyl compound.

brand name

Acne-Aid Cream (Stiefel); Benoxyl (Stiefel); Benzac (Galderma); Benzac W (Galderma); Brevoxyl (Stiefel); Clear By Design (SmithKline Beecham); Dry and Clear (Whitehall-Robins); Epi-Clear (Bristol-Myers Squibb); Fostex BPO Bar, Gel, and Wash (Bristol-Myers Products); Loroxide (Dermik); PanOxyl (Stiefel); Persa-Gel (Ortho Pharmaceutical); Vanoxide (Dermik);Altex.

World Health Organization (WHO)

Benzoyl peroxide slowly releases oxygen and hence is bactericidal. It is also keratolytic, antiseborrheic and irritant. It is used in the treatment of acne. Benzoyl peroxide is listed in the WHO Model List of Essential Drugs.

Synthesis Reference(s)

The Journal of Organic Chemistry, 28, p. 2168, 1963 DOI: 10.1021/jo01044a002

General Description

Benzoyl peroxide appears as odorless white powder or granules. moderately toxic. Sinks in water. (USCG, 1999)

Reactivity Profile

Benzoyl peroxide reacts exothermically withstrong acids, strong bases, amines, reducingagents, and sulfur compounds. Explosionshave been reported when it reacted withcarbon tetrachloride and ethylene (Bolt andJoyce 1947), lithium aluminum hydride(Sutton 1951), N,N-dimethyl aniline (Hornerand Betzel 1953), hot chloroform (NFPA1986), and methyl methacrylate (NFPA1986). Lappin (1948) reported an explosionwhen a bottle was opened. Organic matterentrapped in the threads of the bottleprobably reacted explosively with benzoylperoxide.

Hazard

Highly toxic via inhalation. May explode spontaneously when dry (<1% of water). Never mix unless at least 33% water is present. Skin and upper respiratory tract irritant. Questionable carcinogen.

Health Hazard

The health hazard from benzoyl peroxideis low. It can cause irritation of the skin,mucous membranes, and eyes. An intraperitonealinjection of 250 mg/kg was lethal toadult mice. Systemic toxicity in humans isnot known. It may be mild to moderatelytoxic on an acute basis. The oral LD₅₀ valuein rats is 7710 mg/kg (NIOSH 1986). Itstoxicity from inhalation is low; an LC50 valueof 700 ppm in mice is suggested (ACGIH1986).
Benzoyl peroxide may cause gene damageand DNA inhibition. It has been foundto cause skin tumor. The evidence of its carcinogenicityin animals and humans is inadequate.

Fire Hazard

Benzoyl peroxide can cause a major fire and explosion hazard. It is highly flammable and a strong oxidizer; autoignition temperature 80°C (176°F). It ignites instantly. The rate and violence of decomposition and the potential ease of such ignition or decomposition have been experimentally measured by Noller et al. (1964). Lead pipe deformation (LPD), pressure vessel test (PVT), and self-accelerating decomposition test (SADT) have been performed to measure these explosive characteristics. Heating 5 g of benzoyl peroxide in an aluminum tester containing an aperture vent and 6-atm rupture disk, caused the disk to blow up in 95 seconds when the aperture vent area was less than 174.7 mm². Redried material was more violent. The decomposition hazard was greatly reduced with wet and diluted benzoyl peroxide.
Noller et al. (1964) measured the SADT temperature at 82.2°C (180°F), above which the decomposition was self-accelerating, sudden, and produced smoke.
Benzoyl peroxide is a deflagrant, posing a severe explosion hazard. The compound is sensitive to heavy shock, such as impact or blows, as well as to friction and heat. Especially in the dry state, it is highly dangerous.
A water sprinkler should be used to extinguish fires. Water should be used to keep the containers cool.

Contact allergens

Benzoyl peroxide is an oxidizing agent widely employed in acne topical therapy. It is also used as a polymerization catalyst of dental or industrial plastics and as a decolorizing agent of flours, oils, fats, and waxes. Irritant or allergic dermatitis may affect workers in the electronics and plastics (epoxy resins and catalysts) industries, electricians, ceramic workers, dentists and dental technicians, laboratory technicians, bakers, and acne patients. As it was contained in candles, it also induced contact dermatitis in a sacristan. Patch tests may be irritant.

Pharmacokinetics

Benzoyl peroxide is a topical treatment for acne that generates free radicals to break down comedones and increase the rate of epithelial cell turnover. It has a short duration of action as its active free radical metabolites quickly react to form inactive metabolites. The therapeutic index is wide, as overdoses are rare, however patients may still experience skin peeling. Patients should be counselled regarding increased risks of skin irritation, dryness, and sunburn.

Safety Profile

Poison by intraperitoneal route.Can cause dermatitis, asthmatic effects, testicular atrophy,and vasodilation. An allergen and eye irritant. Humanmutation data reported. Questionable carcinogen withexperimental tumorigenic data. Moderate fire hazard by

Potential Exposure

Used as polymerization initiator, curing agent, and cross-linking agent.

Veterinary Drugs and Treatments

Benzoyl peroxide products are used topically either as gels or in shampoos. Shampoos are generally used for seborrheas, greasy skin (seborrhea oleosa), or crusty pyodermas (such as seborrheic dermatitis/pyoderma commonly seen in Cocker Spaniels). Gels may be useful for treating recurrent localized skin infections (e.g., chin acne), localized Demodex lesions, superficial and deep pyodermas (adjunctive therapy), seborrhea oleosa, and Schnauzer comedo syndrome. Benzoyl peroxide possesses antimicrobial (especially antibacterial), keratolytic and antiseborrheic actions. It also is It has some mild antipruritic activity and wound healing effects, and is thought to increase follicular flushing. Benzoyl peroxide’s antimicrobial activity is due to the oxidative benzoyl peroxy radicals formed that disrupt cell membranes.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 24
48 h afterbreathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a corticosteroid spray.

Carcinogenicity

When repeatedly applied to the skin of mice, BPO was not carcinogenic . However, benzoyl peroxide is a tumor promoter in mice and hamsters, but has shown no complete carcinogenic or tumor-initiating activity . There has been one controversial Japanese report that was interpreted as BPO being a complete carcinogen. However, when the data were critically evaluated, it was found consistent with BPO acting as a skin tumor promoter and not as a carcinogen. The International Agency for Research on Cancer (IARC) has evaluated the carcinogenicity of benzoyl peroxide. They classified it as Group 3. This means there is limited or inadequate evidence of carcinogenicity for animals and inadequate or absent information for humans. In addition, there are other animals and in vitro studies that continue to support the lack of carcinogenic or mutagenic properties for BPO .

Source

Benzoyl peroxide (BPO) was originally derived from chlorhydroxyquinoline, a component of coal tar. Currently, BPO is usually prepared by treating hydrogen peroxide with benzoyl chloride.

Metabolism

The peroxide bond of benzoyl peroxide is cleaved to form 2 benzoyloxy radicals. The benzyoyloxy radicals may interact with other molecules, forming benzoic acid; alternatively, benzoyloxy radicals can break down further to release carbon dioxide and a phenyl radical.

storage

Benzoyl peroxide should be stored in acool and well-ventilated area, isolated fromother chemicals and free of heating andelectrical installations. Dry compound maybe shipped in polyethylene-lined paper bagsor fiber containers packed in wooden boxeso.

Shipping

UN3104 : Organic peroxide type C, solid, Hazard Class: 5.2; Labels: 5.2—Organic peroxide, Technical Name Required. UN3108 : Organic peroxide type E, solid, Hazard Class: 5.2; Labels: 5.2—Organic peroxide, Technical

Purification Methods

Dissolve benzoyl peroxide in CHCl3 at room temperature and precipitate it by adding an equal volume of MeOH or pet ether. Similarly it is precipitated from acetone by adding two volumes of distilled water. It has also been crystallised from 50% MeOH and from diethyl ether. Dry it under vacuum at room temperature for 24hours. Store it in a desiccator in the dark at 0o. When purifying in the absence of water it can be EXPLOSIVE, and operations should be done on a very small scale with adequate protection. Large amounts should be kept moist with water and stored in a refrigerator. [Kim et al. J Org Chem 52 3691 1987, Beilstein 9 IV 777.]

Incompatibilities

May explode when heated above melting point, 103 C. A strong oxidizer. Extremely explosionsensitive to heat, shock, friction, and concussion. May explode or cause fire on contact with reducing agents; combustible substances, organic substances, wood, paper, metal powders, lithium aluminum hydride. Violent reaction with alcohols, organic and inorganic acids, and amines.

Waste Disposal

Pretreatment involves decomposition with sodium hydroxide. The final solution of sodium benzoate, which is very biodegradable, may be flushed into the drain. Disposal of large quantities of solution may require pH adjustment before release into the sewer or controlled incineration after mixing with a noncombustible material.