Naphthalene-2-sulphonic acid

Dermal absorption

Administrative data

Endpoint:

dermal absorption

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Meets generally accepted scientific standards, well documented and acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Principles of method if other than guideline:

In the present study the test substance was assessed for its potential to permeate porcine skin to obtain information on its potential to be absorbed through the skin.

Test material

Test material information

Constituent 1

Reference substance name:

Sodium naphthalene-2-sulphonate

EC Number:

208-523-8

EC Name:

Sodium naphthalene-2-sulphonate

Cas Number:

532-02-5

IUPAC Name:

sodium naphthalene-2-sulfonate

Constituent 2

Reference substance name:

naphthalenesulfonic acid, sodium salt

IUPAC Name:

naphthalenesulfonic acid, sodium salt

Details on test material:

- Name of test material (as cited in study report): Na-NSA
- Physical state: white, solid
- Analytical purity: > 98.0%
- Lot/batch No.: 9611000266 (16.12.1996)
- storage: room temperature

Test animals

Species:

pig

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Administration / exposure

Type of coverage:

not specified

Vehicle:

water

Duration of exposure:

up to 24 hours

Doses:

1mg/mL (339 µL per donor chamber)

No. of animals per group:

in total, eight replicates were used

Control animals:

no

Details on in vitro test system (if applicable):

Porcine ears were obtained from a local slaughter-house on the day of slaughter and before the animals were steam-cleaned. The ear skin was prepared for dissection. The thickness of the dissected skin was 2-3 millimeter. The surface of the skin which was in contact with the test substance during the permeation-assay was 1.13 cm2.In two experiments with each 4 diffusion chambers (chambers are divided in an upper part (donor chamber) and in a lower part (receptor chamber)) the test substance was tested at a concentration of 1 mg/ml dissolved in deionised water.
Each donor chamber was filled with 339 µl of the test substance solution. The diffusion chambers were placed in an incubator at 37° C. Samples (0.5 ml) were drawn from the receptor chambers that contained 7ml 0.9% NaCl following a fixed schedule:0, 0.5, 1, 2, 4, 6, 8 and 24 hours following the application of the test article.These samples were analysed by UV-absorption at 227 nm to determine the concentration of the permeated test substance.The volume of the fluid in the receptor chamber was kept constant by the addition of 0.5 ml of fresh receptor fluid to the receptor chamber immediately after removal of each sample.In order to quantify the data, the amount of permeated test substance divided by the skin surface area was blotted versus time. The approximately linear parts of the graphs (0 to 8 hours) were used to derive the corresponding permeation rates and permeation constants. A time dependent concentration increase of the test substance in the receptor chamber indicates permeability of the skin. The permeation rates and permeation constants were calculated to quantify the data.

Results and discussion

Signs and symptoms of toxicity:

not examined

Dermal irritation:

not examined

Absorption in different matrices:

The results indicate that the skin penetration of the test material was very low within the time scale of the experiments. The mean value of the permeation constants was 2.47x10-4 cm/h in experiment I and 2.48x10-4 cm/h in experiment II.The determination of the test article remaining in the donor chambers after 24 hours indicated that only minor amounts of the test substance are lost from the donor chambers either by permeation through or by binding to the skin. After the experiment the skin patches were extracted with deionised water to remove non covalently bound test material off the skin. The results confirm that only small amounts (approx. 5 µg) of the test substance are extractable off the skin.

Percutaneous absorption

Dose:

339 µL of a 1 mg/mL solution

Parameter:

percentage

Absorption:

ca. 1 %

Remarks on result:

other: 24 h

Remarks:

surface area: 1.13 cm2

Any other information on results incl. tables

In conclusion, it can be stated that during the described permeability test and under the experimental conditions reported, about 1 % of the test article did permeate porcine skin within a time scale of 24 hours.