Benzoyl peroxide

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Benzoyl peroxide
Systematic name Dibenzoyldioxidane
Molecular formula (C6H5CO)2O2 or C14H10O4
Molar mass 242.23 g/mol
CAS number [94-36-0]
Density 1.334 g/cm3
Solubility in Water Poor
Melting point 103–5 °C decomp.
SMILES c1ccccc1C(=O)OOC(=O)c2ccccc2
Hazards
MSDS External MSDS
EU classification Explosive (E)
Irritant (Xi)
NFPA 704
Image:nfpa h1.png Image:nfpa f4 ox.png Image:nfpa r4.png
R-phrases R2, R36, R43
S-phrases S2, S3/7, S14, S36/37/39
Autoignition
temperature		 80°C
RTECS number DM8575000
Except where noted otherwise, data are given for
materials in their standard state (at 25 °C, 100 kPa)
Infobox disclaimer and references
Tube of Basiron, a water-based 5% benzoyl peroxide preparation for the treatment of acne.
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Tube of Basiron, a water-based 5% benzoyl peroxide preparation for the treatment of acne.

Benzoyl peroxide (IPA [ˈbɛnzəʊɪl pəˈrɒksaɪd]) is a chemical in the organic peroxide family. It consists of two benzoyl groups (benzaldehyde with the H of CHO removed) joined by a peroxide group.

Trademarks for benzoyl peroxide include OXY, NeoBenz Micro, Basiron, Brevoxyl, Stioxyl, and Panoxyl.

Contents

[edit] Precautions

Benzoyl peroxide, like most peroxides, is a powerful bleaching agent. Contact with fabric (including clothing and bed linens) or hair can cause permanent color dampening almost immediately. At high concentrations, benzoyl peroxide is highly flammable and explosive and should be handled with care. In the United States, the monograph for benzoyl peroxide is 2.5% to 10% for both prescription and over the counter use.

[edit] Uses

Benzoyl peroxide is effective in the treatment of most forms of acne. It is typically placed over the affected areas in gel or cream form, in concentrations of 2.5% increasing through the usually effective 5% to up to 10%. Research suggests that 5 and 10% concentrations are not significantly more effective than 2.5% and 2.5% is usually better tolerated.[1][2] It commonly causes initial dryness and sometimes irritation, although skin tolerance usually occurs after a week or so. A small percentage of people are much more sensitive to it and liable to suffer burning, itching, peeling and possibly swelling[3]. It is sensible to apply the lowest concentration and build up as appropriate. Once tolerance is achieved, increasing the quantity or concentration a second time and gaining tolerance at a higher level usually gives better subsequent acne clearance. Benzoyl peroxide works as a peeling agent, increasing skin turnover and clearing pores, thus reducing the bacterial count there as well as directly as an antibacterial.

Other common uses for benzoyl peroxide include dyeing hair, and as an active ingredient in teeth whitening systems. It is also used in the preparation of flour, and can be used as an initiator and catalyst for polyester thermoset resins (as an alternative to the much more hazardous methyl ethyl ketone peroxide).

[edit] Safety

Benzoyl peroxide has been in use for many decades, with no obvious particular safety issues being evident.

Benzoyl peroxide breaks down in contact with skin, producing benzoic acid and oxygen, neither of which are significantly toxic.[4]

When applied to skin benzoyl peroxide has been shown to induce cancer, but only when used at 100% concentrations; it has not been shown to do this at the far lower concentrations used for treating acne, and at lower concentrations benzoyl peroxide has been found not to be mutagenic or carcinogenic.[citation needed]

Benzoyl peroxide removes the top layer of skin, which also decreases the sun protective effect (roughly SPF 3). This can cause sunburn and premature aging if sun protection is not worn. If sun protection is used, benzoyl peroxide has a similar effects to glycolic acid peels which are so-called anti-aging treatments.

When used, particularly close to the eye region, a wrinkling effect can be evident. This is merely dry skin and goes away completely a few weeks after the product is discontinued.

[edit] Double Displacement

Mixing sodium peroxide with benzoyl chloride gives benzoyl peroxide and sodium chloride.

[edit] Decomposition

Half-life is 140 hours at 50°C. At 90°C it is already only 1 hour.[citation needed]

[edit] References

  1. ^ Mills, OH Jr, Kligman AM, Pochi P, Comite H (1986). "Comparing 2.5%, 5%, and 10% benzoyl peroxide on inflammatory acne vulgaris.". International Journal of Dermatology 25 (10): 664–667.
  2. ^ Yong, CC (1979). "Benzoyl peroxide gel therapy in acne in Singapore.". International Journal of Dermatology 18 (6): 485–488.
  3. ^ Typical product information leaflets and monographs
  4. ^ "Benzoyl Peroxide" section 3.1.1

[edit] External links


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Acne-treating agents (D10) edit
Topical agents: Azelaic acid, Benzoyl peroxide, Glycolic acid, Light therapy, Salicylic acid, Tea tree oil
Antibiotics: Clindamycin, Co-trimoxazole, Erythromycin, Sulfacetamide, Teicoplanin, Tetracyclines, Trimethoprim, Vancomycin
Hormonal: Antiandrogens, Contraceptives
Retinoids: Adapalene, Isotretinoin, Tazarotene, Tretinoin
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