Sodium dodecylbenzenesulfonate

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

other: published data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Effect of long term topical application of some anionic surfactants on the skin, oral mucous membrane, and tongue.

Author:

Sadai, M. and Mizuno, N.

Year:

1972

Bibliographic source:

Jpn Journal Dermatol. 82:207-221. (in Japanese); cited in: IPCS (1996); Environmental Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) and Related Compounds. WHO, Geneva, Switzerland.

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

LAS was applied to the backs of the rats. On the 16th day of the experiment, skin at the application site and the tissues of the tongue and oral mucosa (to examine the effects of licking) of the rats that received 30% were examined histologically

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

C12-LAS

IUPAC Name:

C12-LAS

Details on test material:

Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts.
LAS, activity: 99.9%

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Administration / exposure

Type of coverage:

occlusive

Vehicle:

other: distilled water

Details on exposure:

LAS was applied for 15 days to the backs of male rats, at daily doses of 0.5 g of solutions at 20 and 30% (about 286 and 427 mg/kg bw/day).

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

15 days

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
286 and 427 mg/kg bw day
Basis:
nominal per unit body weight

Control animals:

yes

Details on study design:

LAS was applied for 15 days to the backs of male rats, at daily doses of 0.5 g of solutions at 20 and 30% (about 286 and 427 mg/kg bw/day). On the 16th day of the experiment, the animals were assessed. Body weight gain was suppressed in the 20% group (286 mg/kg bw/day) and the body weight was decreased in the 30% group (427 mg/kg bw/day). An infiltrating, yellowish-reddish brown crust was observed after 2-3 days in the lower dose group, and after 1-2 days in the high dose group. After 4-6 days the crust was abraded and erosion occurred at the abraded site.

Examinations

Sacrifice and pathology:

On the 16th day of the experiment, skin at the application site and the tissues of the tongue and oral mucosa (to examine the effects of licking) of the rats that received 30% were examined histologically

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Ophthalmological findings:

not examined

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Details on results:

Body weight gain was suppressed in the 20% group (286 mg/kg bw/day) and the body weight was decreased in the 30% group (427 mg/kg bw/day). An infiltrating, yellowish-reddish brown crust was observed after 2-3 days in the lower dose group, and after 1-2 days in the high dose group. After 4-6 days the crust was abraded and erosion occurred at the abraded site.
Histological examinations of the application site revealed severe necrosis of the region from the epidermis cuticle to the upper layer of the dermis, severe infiltration of leukocytes in the necrotic site, and diffuse inflammatory cell infiltration of all layers of the corium.
The effects on body weight are to be considered related to the LAS irritation.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

< 286 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

clinical signs

mortality

2

Dose descriptor:

LOAEL

Effect level:

286 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

body weight and weight gain

clinical signs

mortality

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

The LOAEL for body weight effects is 286 mg/kg bw/day, the lower dose tested.
The NOAEL for body weight effects is <286 mg/kg bw/day.

Executive summary:

LAS was applied for 15 days to the backs of male rats, at daily doses of 0.5 g of solutions at 20 and 30% (about 286 and 427 mg/kg bw/day). On the 16thday of the experiment, the animals were assessed. Body weight gain was suppressed in the 20% group (286 mg/kg bw/day) and the body weight was decreased in the 30% group (427 mg/kg bw/day). An infiltrating, yellowish-reddish brown crust was observed after 2-3 days in the lower dose group, and after 1-2 days in the high dose group. After 4-6 days the crust was abraded and erosion occurred at the abraded site. Histological examinations of the application site revealed severe necrosis of the region from the epidermis cuticle to the upper layer of the dermis, severe infiltration of leukocytes in the necrotic site, and diffuse inflammatory cell infiltration of all layers of the corium. The effects on body weight are to be considered related to the LAS irritation.

The LOAEL for these effects is 286 mg/kg bw/day, the lower dose tested.

The NOAEL for these effects is<286 mg/kg bw/day.