Benzenesulfonic acid, 4-C20-24 (even numbered) sec-alkyl derivs., sodium salts

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study in peer-reviewed publication.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

dermal absorption in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study in peer-reviewed publication.

Reason / purpose for cross-reference:

reference to same study

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

Radiolabelling:

yes

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

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

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

Dose:

250 micrograms

Parameter:

percentage

Absorption:

< 0.3 %

Remarks on result:

other: 24 hrs after exposure

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.

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%.

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

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium dodecylbenzenesulfonate

EC Number:

246-680-4

EC Name:

Sodium dodecylbenzenesulfonate

Cas Number:

25155-30-0

IUPAC Name:

sodium 2-dodecylbenzenesulfonate

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:

human

Sex:

female

Administration / exposure

Duration of exposure:

48 hrs

Doses:

0.1 ml of 3 mM solution

No. of animals per group:

four skin samples

Details on study design:

- 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.

Details on in vitro test system (if applicable):

SKIN PREPARATION
- Source of skin: human cadavars
- Ethical approval if human skin:
- Type of skin: abdominal
- Preparative technique: Epidermal samples were heated at 58 degrees C for 2 min. Samples were placed in 1 cm diamter penetration cells, and saline with 0.012% penicillin, 0.01% streptomycin was placed on both surfaces of the cells. The cells were equilibrated at 37 degrees C for 24 hrs.
- Membrane integrity check: Only cells with electrical resistance greater than 50,000 ohms were used.
- Storage conditions: -70 degree C

Results and discussion

Signs and symptoms of toxicity:

not examined

Dermal irritation:

yes

Remarks:

some swelling was seen after 48 hrs of contact

Absorption in different matrices:

Only 30% of the test substance was removed by rinsing, with 70 % remaining associated with the skin.

Percutaneous absorption

Percutaneous absorption 1

Dose:

152.9 micrograms/cm^2

Parameter:

percentage

Absorption:

< 0.07 %

Remarks on result:

other: 2 hrs

Percutaneous absorption 2

Dose:

152.9 micrograms/cm^2

Parameter:

percentage

Absorption:

< 0.07 %

Remarks on result:

other: 6 hrs

Percutaneous absorption 3

Dose:

152.9 micrograms/cm^2

Parameter:

percentage

Absorption:

< 0.07 %

Remarks on result:

other: 24 hrs

Percutaneous absorption 4

Dose:

152.9 micrograms/cm^2

Parameter:

percentage

Absorption:

< 0.07 %

Remarks on result:

other: 48 hrs

Applicant's summary and conclusion

Conclusions:

The in vitro penetration through human skin after a 48 hr exposure was < 0.07%.

Executive summary:

Radiolabelled test substance was applied (0.1 ml of a 3 mM solution) to samples of human abdominal skin from four female cadavars. Exposure time was 48 hrs. Analysis by liquid scintillation counting was done at 0.5, 1, 2, 3, 4, 6, 7, 8, 24, and 48 hrs. Penetration through human skin was negligible, with < 0.07% absorbed in 48 hrs.