(1-methylethyl)-1,1'-biphenyl

Endpoint summary

Description of key information

The acute toxicity of MIPB is low by all routes of exposure. High dosage is rarely lethal to rats or rabbits, but produces distinct systemic effects by all routes, and in addition skin irritation following dermal exposure. The severity of effects on inhalation is less clear, as only toxicity data following 1 hour 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: Study meets basic scientific principles; comparable to guideline study; basic data given

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

; 10 animals per dose level, no pathology, only one sex tested, limited reporting

GLP compliance:

no

Remarks:

pre-GLP stuidy

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 200 - 300 g
- Fasting period before study: 24 h
- Animals were fed, housed and watered in accordance with standard laboratory procedures.

Route of administration:

oral: gavage

Vehicle:

not specified

Doses:

1, 3, 5, 8, 10, and 15 g/kg bw

No. of animals per sex per dose:

10

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations at 1, 3, 6, 24, 48, 72 h, and daily thereafter; no information on weighing
- Necropsy of survivors performed: no
- Other examinations performed: clinical signs

Statistics:

LD 50 was determined in accordance with the method of Miller and Tainter (Proc. Soc. Exp. Biol. Med. NY , 57, 261-264, 1944)

Sex:

not specified

Dose descriptor:

LD50

Effect level:

4 650 mg/kg bw

Based on:

test mat.

Remarks on result:

other: S.E. = 640 mg/kg bw

Clinical signs:

other: Decreased locomotor activity, piloerection, ataxia, ptosis. In the lowest dose group, slight systemic toxicity prevalently related to CNS effects (decreased locomotor activity) was observed. 4 days after treatment, the test animals appeared normal again.

Gross pathology:

no data

Other findings:

--

Mortality

 

Dose [g/kg bw]	Animals per Group	Day			Total
		2	3	4
1	10	0	0	0	0/10
3	10	0	1	1	2/10
5	10	0	4	2	6/10
8	10	2	5	1	8/10
10	10	3	3	2	8/10
15	10	0	3	7	10/10

 

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Monoisopropylbiphenyl is only slightly acute toxic. LD50 was determined to be 4650 mg/kg bw. Classification according EU regulations is not required.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

4 650 mg/kg bw

Quality of whole database:

limited, acceptable for assessment

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

limited

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

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: Study based on national standard, acceptable for assessment, but with limited documentation

Qualifier:

according to guideline

Guideline:

other: Code of Federal Regulation - 16 CFR, Part 1500.3

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Bunnyville Farms, littletown, Pennsylvania
- Age at study initiation: no data
- Weight at study initiation: 2.3 - 3.1 kg

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: one square inch (6.25 cm²); 2/4 animals per group, abraded or nonabraded skin
- Type of wrap if used: gauze patch wrapped with nonadsorbant binder.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): rinsed with tap water

Duration of exposure:

24 h

Doses:

4640 and 6000 mg/kg bw

No. of animals per sex per dose:

4 per dose, in total 8 animals

Control animals:

not required

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

not applicable

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality, except
1/4 animals (group 4640 mg/kg) on day 2, but considered unrelated to the treatnment and was replaced.

Clinical signs:

other: Depression in all animals but 1/4 in the 6000-mg/kg group, anorexia in 3/4 and phonation in 1/4 animals in the 4640-mg/kg group.

Gross pathology:

1/4 animals jelly-like material in the intestines,
no other particular findings in any of the other animals.

Other findings:

Signs of dermal irritation observed in all of the rabbits at the 4640 mg/kg level included slight to moderate erythema and slight desquamation.
At the 6000 mg/kg level, slight to moderate erythema and slight desquamation occurred in all of the animals with the findings being of longer duration in the abraded site animals. Edema occurred on Day 1 in one intact site animal.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Quality of whole database:

limited, acceptable for assessment

Additional information

Justification for selection of acute toxicity – inhalation endpoint
No effect level could be established based on data available.

Justification for classification or non-classification

Based on available data, no classification for acute toxicity according to Regulation (EC) No 1272/2008 is required.