N-cyclohexylbenzothiazole-2-sulfenamide

Endpoint summary

Description of key information

The acute toxicity of the test substance CBS in rodents is very low after oral and dermal administration. The acute oral LD50 value in rats is 5300 mg/kg (Monsanto Co. 1973) and the dermal LD50 value in rabbits is greater than 7940 mg/kg bw. (Monsanto Co. 1973). No acute inhalation study is available.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: acceptable documented study report, which meets basic scientific principles

Principles of method if other than guideline:

The acute oral toxicity of CBS was evaluated in an acceptable documented study with Sprague-Dawley Albino rats. A 25 % solution-suspension of CBS in corn oil was administered by gavage to 4 groups of 5 Sprague-Dawley albino rats at doses of 3980, 5010, 6310 and 7940 mg/kg bw. A 7-day observation period followed administration.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Route of administration:

oral: gavage

Vehicle:

corn oil

Doses:

3980, 5010, 6310, 7940 mg/kg bw

No. of animals per sex per dose:

5 per dose group (mixed males and females; 2-3 males per group, 2-3 females per group).

Control animals:

no

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

5 300 mg/kg bw

Based on:

test mat.

Remarks on result:

other: Signs of Intoxication: Reduced appetite and activity (two to four days in survivors), increased weakness, ocular discharge, slight tremors, collapse, and death Gross autopsy: lung and liver hyperemia and acute gastrointestinal inflammation.

Mortality:

3980 mg/kg bw: 0/5 animals died; 5010 mg/kg bw: 1/5 animals died; 6310 mg/kg bw: 4/5 animals died; 7940 mg/kg bw: 4/5 animals died.

Clinical signs:

other: Reduced appetite and activity (two to four days in survivors), increased weakness, ocular discharge, slight tremors, collapse, and death.

Gross pathology:

Decendents: lung and liver hyperemia and acute gastrointestinal inflammation.
Survivors: Vicera of surviving animals appeared normal at sacrifice.

Signs of Intoxication: Reduced appetite and activity (two to four days in survivors), increased weakness, ocular discharge, slight tremors, collapse, and death.

Gross autopsy:

Decendents: lung and liver hyperemia and acute gastrointestinal inflammation.

Survivors: Vicera of surviving animals appeared normal at sacrifice.

Interpretation of results:

GHS criteria not met

Conclusions:

LD50 = 5300 mg/kg bw.

Executive summary:

The acute oral toxicity of CBS was evaluated in an acceptable documented study with Sprague-Dawley Albino rats. A 25 % solution-suspension of CBS in corn oil was administered by gavage to t groups of 5 (mixed males and females) Sprague-Dawley albino rats at doses of 3980, 5010, 6310 and 7940 mg/kg bw. A 7-day observation period followed administration. The acute oral LD50 for CBS for male and female rats was calculated to be 5300 mg/kg bw (Monsanto Co. 1973).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

discriminating dose

Value:

5 300 mg/kg bw

Quality of whole database:

Several acute oral toxicity studies in rats and mice demonstrate a LD50 > 2000 mg/kg bw.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: limited documented study report, with restrictions (e.g. no local effects recorded), sufficient for risk assessment

Principles of method if other than guideline:

A 40% solution-suspension of CBS in corn oil was applied for 24 h directly to the clipped intact skin of New Zealand albino rabbits at doses of 5010 and 7940 mg/kg bw (1 and 2 animals, resp.) using semi-occlusive dressing. A 14-d observation period followed application.

GLP compliance:

no

Test type:

standard acute method

Species:

rabbit

Strain:

New Zealand White

Sex:

male/female

Type of coverage:

semiocclusive

Vehicle:

corn oil

Duration of exposure:

24 h

Doses:

5010, 7940 mg/kg bw.

No. of animals per sex per dose:

1-2/dose.

Control animals:

no

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 7 940 mg/kg bw

Based on:

test mat.

Remarks on result:

other: Clinical signs: reduced appetite and activity three to five days.

Mortality:

No mortality occured (5010 mg/kg bw (0/1), 7940 mg kg bw (0/2)).

Clinical signs:

other: Reduced appetite and activity three to five days.

Gross pathology:

Viscera of animals appeared normal at sacrifice.

No mortality occured (5010 mg/kg bw (0/1), 7940 mg kg bw (0/2)).

Clinical signs: reduced appetite and activity three to five days.

Viscera of animals appeared normal at sacrifice.

Interpretation of results:

GHS criteria not met

Conclusions:

LD50 > 7940 mg/kg bw.

Executive summary:

The acute dermal toxicity of the test substance CBS was evaluated with New Zealand Albino rabbits in a limited documented study. A 40% solution-suspension of CBS in corn oil was applied for 24 h directly to the clipped intact skin of New Zealand albino rabbits at doses of 5010 and 7940 mg/kg bw (1 and 2 animals, resp.) using semi-occlusive dressing. A 14 -d observation period followed application. No mortality was observed up to 7940 mg/kg bw. Clinical signs noted included reduced appetite and activity for 3 to 5 days. Viscera of animals appeared normal at sacrifice (Monsanto 1973).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

7 940 mg/kg bw

Quality of whole database:

Limited documented study report, with restrictions, but sufficient for risk assessment.

Additional information

Acute toxicity: oral

The acute oral toxicity of CBS was evaluated in an acceptable documented study with Sprague-Dawley Albino rats. A 25 % solution-suspension of CBS in corn oil was administered by gavage to 4 groups of 5 (mixed males and females) Sprague-Dawley albino rats at doses of 3980, 5010, 6310 and 7940 mg/kg bw. A 7-day observation period followed administration. The acute oral LD50 for CBS for male and female rats was calculated to be 5300 mg/kg bw (Monsanto Co. 1973). In another acute oral toxicity study with rats, an oral LD50 > 5000 mg/kg bw was stated (Sumitomo Chemicals Co. 1977 cited in EU Risk Assessment 2007). In addition, in a limited documented publication an oral LD50 of >8000 mg/kg bw was stated for mice (Hasegawa 1989).

 

Acute toxicity: dermal

The acute dermal toxicity of the test substance CBS was evaluated with New Zealand Albino rabbits in a limited documented study. A 40% solution-suspension of CBS in corn oil was applied for 24 h directly to the clipped intact skin of New Zealand albino rabbits at doses of 5010 and 7940 mg/kg bw (1 and 2 animals, resp.) using semi-occlusive dressing. A 14-d observation period followed application. No mortality was observed up to 7940 mg/kg bw. Clinical signs noted included reduced appetite and activity for 3 to 5 days. Viscera of animals appeared normal at sacrifice (Monsanto 1973).

Justification for classification or non-classification

The acute oral LD50 value in rats is 5300 mg/kg (Monsanto Co. 1973) and the dermal LD50 value in rabbits is greater than 7940 mg/kg bw. (Monsanto Co. 1973). No acute inhalation study is available.

According to CLP classification criteria (Regulation (EC) No 1272/2008) a classification is not justified.