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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Dermal absorption

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Administrative data

Endpoint:
dermal absorption in vitro / ex vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well documented publication which meets basic scientific principles.

Data source

Reference
Reference Type:
publication
Title:
The percutaneous absorption of some anionic surfactants
Author:
Howes, D.
Year:
1975
Bibliographic source:
J. Soc. Cosmet. Chem. 26:47-63

Materials and methods

Principles of method if other than guideline:
In vitro penetration study of several fatty acids through rat skin.
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Decanoic acid
EC Number:
206-376-4
EC Name:
Decanoic acid
Cas Number:
334-48-5
IUPAC Name:
decanoic acid
Constituent 2
Reference substance name:
dodecanoic acid
IUPAC Name:
dodecanoic acid
Constituent 3
Reference substance name:
tetradecanoic acid
IUPAC Name:
tetradecanoic acid
Constituent 4
Reference substance name:
hexadecanoic acid
IUPAC Name:
hexadecanoic acid
Constituent 5
Reference substance name:
octadecanoic acid
IUPAC Name:
octadecanoic acid
Radiolabelling:
yes

Test animals

Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 100-120 g

Administration / exposure

Type of coverage:
open
Vehicle:
other: The test materials were applied as soap solutions (sodium salts).
Duration of exposure:
24 h
Doses:
- Nominal doses: 300 µg C10:0, 325 µg C12:0, 375 µg C14:0, 425 µg C16:0 and 450 µg C18:0/4.9 cm² skin
- Dose volume: 0.051 ml/cm²
No. of animals per group:
not specified
Control animals:
no
Details on in vitro test system (if applicable):
SKIN PREPARATION
- Source of skin: rat dorsal skin
- Type of skin: full thickness skin
- Preparative technique: Dorsal skin was clipped 24 h before cervical dislocation. The skin was excised and mounted in 2.5 cm penetration cells similar to those described by Ainsworth (J Soc Cosmet Chem 11:69 (1960)).



PRINCIPLES OF ASSAY
- Diffusion cell: similar to those described by Ainsworth (J Soc Cosmet Chem 11:69 (1960)).
- Receptor fluid: saline
- Occlusion: no

Results and discussion

Percutaneous absorptionopen allclose all
Dose:
61.22 µg C10:0/cm²
Parameter:
percentage
Absorption:
ca. 14 %
Remarks on result:
other: 24 h
Remarks:
8.6 ± 3.4 µg C10:0/cm² absorbed (n=3)
Dose:
66.33 µg C12:0/cm²
Parameter:
percentage
Absorption:
ca. 10.9 %
Remarks on result:
other: 24 h
Remarks:
7.2 ± 3.7 µg C12:0/cm² absorbed (n=3)
Dose:
76.53 µg C14:0/cm²
Parameter:
percentage
Absorption:
ca. 9 %
Remarks on result:
other: 24 h
Remarks:
6.9 ± 3.0 µg C14:0/cm² absorbed (n=3)
Dose:
86.73 µg C16:0/cm²
Parameter:
percentage
Absorption:
0.2 %
Remarks on result:
other: 24 h
Remarks:
0.2 ± 0.1 µg C16:0/cm² absorbed (n=3)
Dose:
91.84 µg C18:0/cm²
Parameter:
percentage
Absorption:
< 0.1 %
Remarks on result:
other: 24 h
Remarks:
< 0.1 µg C18:0/cm² absorbed (n=3)
Conversion factor human vs. animal skin:
no data

Any other information on results incl. tables

The results show no measurable penetration of the C18:0 soap through rat skin up to 24 h after application, but 0.2 µg/cm² of the C16:0 soap had penetrated at 24 h. Some 7.5 µg of the C10:0, C12:0 and C14:0 soaps had penetrated per cm² at 24 h but the results were not significantly different for the three soaps. For the three soaps which penetrated the skin there was a lag time of 1 h before any measurable penetration occurred, but after this the rate of penetration steadily increased. At the

end of the experiment,i .e. 24 h after application, between 60 and 70% of the applied [14C] soaps were rinsed from the skin and 30-40% was associated with the skin.

Applicant's summary and conclusion

Conclusions:
The in vitro penetration of C10, C12, C14, C16 and C18 fatty acids (as sodium salt solutions) through rat skin decreases with increasing chain length. At 86.73 µg C16/cm² and 91.84 µg C18/cm², about 0.23% and less than 0.1% of the C16 and C18 soap solutions is absoberd after 24 h exposure, respectively.