Registration Dossier

Toxicological information

Dermal absorption

Currently viewing:

Administrative data

Endpoint:
dermal absorption in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Benzoyl Peroxide : Percutaneous Penetration and Metabolic Disposition
Author:
Nacht S, Yeung D, Beasley JN, Anjo MD and Maibach HI
Year:
1981
Bibliographic source:
J. Am. Acad. Dermatol., 4(1):31-37

Materials and methods

Principles of method if other than guideline:
Diffusion cell technic with excised human skin
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Dibenzoyl peroxide
EC Number:
202-327-6
EC Name:
Dibenzoyl peroxide
Cas Number:
94-36-0
Molecular formula:
C14H10O4
IUPAC Name:
benzoyl benzenecarboperoxoate
Details on test material:
No data
Radiolabelling:
yes
Remarks:
14C-benzoyl peroxide

Test animals

Species:
human

Administration / exposure

Type of coverage:
occlusive
Duration of exposure:
8 hours
Doses:
900 µg/cm²

Results and discussion

Absorption in different matrices:
Rinse (skin surface): 4,350 µg*, 95.5%† as Benzoyl peroxide
Soaks (skin layers): 120 µg, 2.6% as Benzoyl peroxide and benzoic acid
Buffer (dermal side): 86 µg, 1.9% as Benzoic acid
Total: 4,556 µg, 100%
*Average of two diffusion cells.
†Percent of the total amount recovered.
Total recovery:
100%
Percutaneous absorptionopen allclose all
Dose:
4556 µg
Parameter:
percentage
Absorption:
4.5 %
Remarks on result:
other: 8 hours
Remarks on result:
other: Dermal penetration: 5.1 µg/cm²/hour

Any other information on results incl. tables

All radioactive spots matched exactly areas that had been circled on the TLC plates under UV light. These areas were identified as either ben zoyl peroxide or benzoic acid by comparing their Rf values with the standards. Of the 4,556 µg of radiolabeled benzoyl peroxide applied to the surface of the skin discs, 1.9% (86 µg) penetrated through the skin and was recovered as benzoic acid from the receptor buffer solution. The skin discs contained 2.6% of the radiolabel (120 µg), approximately one half ot which was benzoyl peroxide and one half benzoic acid. Thus, the total amount of benzoyl peroxide delivered to the skin under maximal "steady

state '' conditions was 206 µg in an 8-hour period, or 4.5% of the applied dose. This represents a penetration of 5.1 µg/cm² /hour. Most (95.5%) of the benzoyl peroxide originally applied topically was recovered unchanged from the skin surface at the end of the 8-hour period.

Applicant's summary and conclusion

Executive summary:

The transepidermal penetration and metabolic disposition of 14C-benzoyl peroxide were assessed in vitro (excised human skin). In vitro, 4.5% of the benzoyl peroxide dose penetrated into the skin, through the stratum corneum or the follicular openings, or both, and was recovered on the dermal side as benzoic acid. It was concluded that only benzoic acid enter the systemic circulation and did so by diffusing into the blood vessels of the dermis.