Alkylbenzenesulphonic acid compound with alkanolamine

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

the tested substance is the acid part of the compound

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:

Unnamed

Year:

1975

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

Test material form:

solid: compact

Details on test material:

- Name of test material (as cited in study report): LAS (CAS #25155-30-0); activity: >99%
- 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 or test system 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%.