Benzenesulfonic acid, 4-mono-C20-24 (even numbered)-alkyl derivs., magnesium salts

Dermal absorption

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:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: acceptable well-documented publication which meets basic scientific principles

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1975

Materials and methods

Test guideline

Qualifier:

no guideline followed

GLP compliance:

no

Test material

Test material information

Constituent 1

Test material form:

solid - liquid: suspension

Details on test material:

- Name of test material (as cited in study report): Sodium dodecylbenzene sulphonate (DOBC)
- Molecular formula (if other than submission substance): C18H29NaO3S
- Molecular weight (if other than submission substance): 349.48
- Smiles notation (if other than submission substance):CCCCCCCCCCCCC1=CC(=CC=C1)S(=O)(=O)[O-].[Na+]
- InChl (if other than submission substance): 1S/C18H30O3S.Na/c1-2-3-4-5-6-7-8-9-10-11-13-17-14-12-15-18(16-17)22(19,20)21;/h12,14-16H,2-11,13H2,1H3,(H,19,20,21);/q;+1/p-1
- Structural formula attached as image file (if other than submission substance): see Fig.1
- Substance type: organic salt
- Physical state: no data
- Analytical purity:chemically pure determined by thin layer chromatography and isotope dilution analysis.
- Radiochemical purity (if radiolabelling): radiochemically pure determined by thin layer chromatography and isotope dilution analysi
- Specific activity (if radiolabelling): 8.5 µCi/mg
- Locations of the label (if radiolabelling): 1-alkyl position

Radiolabelling:

yes

Test animals

Species:

other: dorsal skin (rat) and female abdominal epidermis (human)

Strain:

other: Colworth-Wistar rats; human

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:

other: in vitro penetration through the skin

Vehicle:

other: 25% polyethylene glycol in water or water only

Duration of exposure:

2, 6, 24 hours (rat, human) and 48 hours (human)

Doses:

- Nominal doses: DOBS concentration in solutions was 1.2 mg/mL (two test solutions of the [14C] DOBS were used, the first a 3 mM solution in 25% v/v Polyethylene Glycol 400 in water and a second a 3 mM suspension in water);
- Dose volume: 0.25 mL of each test solution was applied to the rat skin (4.9 cm²) and 0.1 mL to the human epidermal samples (0.78 cm²).

No. of animals per group:

Not relevant

Control animals:

no

Details on study design:

DOSE PREPARATION
- Method for preparation of dose suspensions: suspensions were prepared by homogenizing and equilibration in an all glass homogenizer.


APPLICATION OF DOSE

VEHICLE
- Concentration (if solution): 25% v/v Polyethylene Glycol 400 in water

ANALYSIS
- Method type(s) for identification: liquid scintillation counting

Details on in vitro test system (if applicable):

Not reported

Results and discussion

Signs and symptoms of toxicity:

not examined

Dermal irritation:

not examined

Absorption in different matrices:

The results show no measurable penetration (<0.1 µg/cm²) of DOBS through the rat skin up to 24 h after application. DOBC did not penetrate through the human epidermis until 48 hours after application (<0.1 µg/cm²). Permeability constant of 0.1 µcm/min (= 1.0E-7cm/min) was calculated for the isolated human epidermis 6 and 24 hours after skin contact.

Total recovery:

- Total recovery (rat skin): 30% [14C] DOBS was recovered in the rinsings and 70% remained associated with the skin of rats;
-Total recovery (human epidermis): 30-50% of [14C] DOBC retained in the human epidermis after rinsing;
- Limit of detection (LOD): 0.1 µg/cm².

Percutaneous absorption

Percutaneous absorption 1

Dose:

0.1 µg/cm²

Parameter:

percentage

Absorption:

0.16 %

Remarks on result:

other: 2, 6, 24 hours (rat)

Remarks:

based on the applied amount of 0.25 mL DOBC (concentration in vehicle 1.2 mg/mL) to the rat skin of 4.9 cm² and penetration of 0.1 µg/cm² (lower limit of detection was taken as worst-case).

Percutaneous absorption 2

Dose:

0.1 µg/cm²

Parameter:

percentage

Absorption:

0.07 %

Remarks on result:

other: 2, 6, 24 and 48 hours (human)

Remarks:

based on the applied amount of 0.1 mL DOBC (concentration in vehicle 1.2 mg/mL) to the human epidermis of 4.9 cm² and penetration of 0.1 µg/cm² (lower limit of detection was taken as worst-case).

Applicant's summary and conclusion

Conclusions:

No significant penetration through the skin can be expected for dodecyl benzene sulphonate.

Executive summary:

Dodecylbenzene sulphonate (DOBC) was studied in in vitro penetration study through rat skin and human epidermis. Two test solutions of the [14C] DOBS were used, the first a 3 mM solution in 25% v/v Polyethylene Glycol 400 in water and a second a 3 mM suspension in water. 0.25 mL of the test solution was applied to the rat skin (4.9 cm²) and 0.1 mL to the human epidermal samples (0.78 cm²). The concentration of the test material in solutions was 1.2 mg/mL. After 2, 6 and 24 hours (rats) or after 0.5, 1, 2, 3, 4, 6, 7, 8, 24 and 48 hours (human) of exposure, the skin samples were washed with excess of water and the radioactivity was measured in the rinsings and in the tested skin samples to determine the penetration rates. The results show no measurable penetration (<0.1 µg/cm²) of DOBS through the rat skin up to 24 hours. DOBC did not penetrate human epidermis as well (<0.1 µg/cm²). 30% [14C] DOBS was recovered in the rinsings and 70% remained accociated with the skin of rats. 30-50% of [14C] DOBC retained in the human epidermis after rinsing.

To calculate percutaneous absorption rates, penetration of 0.1 µg/cm², the lower limit of detection was taken as worst-case. Based on the applied amount of 0.25 mL to the rat skin (4.9 cm²) and 0.1 mL to the human epidermis (0.78 cm²) and taken into account concentration of DOBC in vehicle of 1.2 mg/mL, 0.16% and 0.065% absorption through the skin was calculated for the rat skin and human epidermis, respectively.