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Toxicological information

Dermal absorption

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Administrative data

Endpoint:
dermal absorption in vivo
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented study in peer-reviewed publication.

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

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Radiolabelled test substance (3 mM solution) was applied to the shaved skin of female rats. The exposure lasted 15 min, after which is was rinsed off. After a 24 hr observation period during feces, urine, and expired air was collected, the animals were sacrificed and the excised skin was examined by autoradiography
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): sodium p-1-[1-14C]-dodecylbenzenesulphonate
- Analytical purity: determined to be chemically pure by thin layer chromatography
- Radiochemical purity (if radiolabelling): determined to be radioactively pure by isotope dilution analysis
- Specific activity (if radiolabelling): > 99%
Radiolabelling:
yes

Test animals

Species:
rat
Strain:
other: Colworth-Wistar
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 100-120 g
- Housing: sealed metabolism cages
- Individual metabolism cages: yes

ENVIRONMENTAL CONDITIONS
- Air changes (per hr): 1.5 L/min

Administration / exposure

Type of coverage:
open
Vehicle:
other: Two test solutions were made: water, and 25% polyethylene glycol 400 in water.
Duration of exposure:
15 min
Doses:
- Nominal doses: 3 mM solution
- Dose volume: 0.2 ml
No. of animals per group:
no data
Control animals:
no
Details on study design:
DOSE PREPARATION
- Method for preparation of dose suspensions: The test substance was added to the vehicle and homogenized and equilibrated at 40 degrees C for 24 hrs. The pH was then adjusted to 9.5 by adding 0.01 n NaOH or HCl.

TEST SITE
- Preparation of test site: 24 hrs before application, hair was removed with clippers. Only animals with intact skin were used.
- Area of exposure: 7.5 cm^2

SITE PROTECTION / USE OF RESTRAINERS FOR PREVENTING INGESTION: yes: Animals were anesthetized during exposure. During the 24 hr observation period the animals were fitted with restraining collars or non-occlusive patches. Non-occlusive patches were made of three layers of surgical gauze 1 cm larger in each dimension than the exposure area. Over this, a stainless steel 100 mesh gauze was placed and secured with surgical strapping with holes punctured in it.

SAMPLE COLLECTION
- Collection of urine and faeces: for 24 hrs after exposure
- Collection of expired air: for 24 hrs after exposure

SAMPLE PREPARATION
- Preparation details: feces were freezed dried, carcasses were homogenized in a blender and then freeze dried

ANALYSIS
- Method type(s) for identification: Liquid scintillation counting, excised skin was examined by autoradiography

Results and discussion

Signs and symptoms of toxicity:
not specified
Dermal irritation:
not specified
Absorption in different matrices:
- Non-occlusive cover: < 2 micrograms
- Skin wash: 135 +/- 27 micrograms
- Skin test site: Heavy deposition was seen on the skin surface, and in the upper hair follicles, 11+/-4 micrograms
- Urine: none
- Faeces: none
Percutaneous absorption
Dose:
250 micrograms
Parameter:
percentage
Absorption:
< 0.3 %
Remarks on result:
other: 24 hrs after exposure

Any other information on results incl. tables

The amount of test substance that penetrated the skin was below the detection limit of 0.1 micrograms/cm2 or less than 0.3% of the initial dose.

Applicant's summary and conclusion

Conclusions:
The in vivo penetration through rat skin after a 15 min exposure was < 0.3%.
Executive summary:

Radiolabelled test substance (3 mM solution) was applied to the shaved skin of female rats. The exposure lasted 15 min, after which is was rinsed off. After a 24 hr observation period during feces, urine, and expired air was collected, the animals were sacrificed and the excised skin was examined by autoradiography. Results show that the test substance, which is of low solubility, did not penetrate through the skin to any significant degree. The amount of test substance penetrating the skin was below the detection limit. The penetration through rat skin was < 0.3%.