Registration Dossier

Administrative data

Endpoint:
repeated dose toxicity: dermal
Adequacy of study:
weight of evidence
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Data source

Materials and methods

Results and discussion

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The repeated dose toxicity dermal is scientifically unjustified because only not relevant extremely low amounts of fatty acid C16-18, sodium salt are able to penetrate the skin membrane due to its hydrophilicity. This statement is supported by the study of Howes (see 5.1.1.). He examined the penetration in vitro through human epidermis of anionic surfactants, including fatty acid C16, sodium salt and fatty acid C18, sodium salt. The in vitro penetration through human skin of the C16:0 soap was 0.3 µg/cm2 after 24 hours and of the C18:0 soap 0.1 µg/cm2. This low penetration rates of the C16: 0 and C18:0 soaps suggest that little or none of these would penetrate from a 15 min wash and rinse in vivo. Thus, there is no relevant internal exposure expected.
Executive summary:

The repeated dose toxicity dermal is scientifically unjustified because only not relevant extremely low amounts of fatty acid C16-18, sodium salt are able to penetrate the skin membrane due to its hydrophilicity. This statement is supported by the study of Howes (see 5.1.1.). He examined the penetration in vitro through human epidermis of anionic surfactants, including fatty acid C16, sodium salt and fatty acid C18, sodium salt. The in vitro penetration through human skin of the C16:0 soap was 0.3 µg/cm2 after 24 hours and of the C18:0 soap 0.1 µg/cm2. This low penetration rates of the C16: 0 and C18:0 soaps suggest that little or none of these would penetrate from a 15 min wash and rinse in vivo. Thus, there is no relevant internal exposure expected.