4-tert-butylbenzonitrile

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

january- october 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

4-tert-Butylbenzonitriile

IUPAC Name:

4-tert-Butylbenzonitriile

Constituent 2

Reference substance name:

4-tert-butylbenzonitrile

EC Number:

224-137-2

EC Name:

4-tert-butylbenzonitrile

Cas Number:

4210-32-6

Molecular formula:

C11H13N

IUPAC Name:

4-tert-butylbenzonitrile

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): 4-tert-Butylbenzonitril
- Physical state: liquid
- Analytical purity: > 94.2 %
- Impurities (identity and concentrations): 3-tert-Butylbenzonitril
- Lot/batch No.: FHI/TVT 281098
- Storage condition of test material: refrigerator (2-8 °C), in the dark

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Forschungsinstitut für Versuchstierzucht, A-2325 Himberg.
- Age at study initiation: Approximately 8 weeks (males) and 12 weeks (females) at the time of administration.
- Weight at study initiation: 186 - 246 g
- Fasting period before study: Feed was withdrawn the evening before the administration of the test substance and was offered again about three hours afterwards.
- Housing: Single caging in Makrolon cage type II (39 cm x 23 cm x 15 cm). Wire mesh lids. Sanitization of cages once a week.
- Diet (e.g. ad libitum): Altromin 1314 forte, gamma irradiated with 25 kGy 60Co ad libitum. (Producer: Altromin GmbH, D-32791 Lage)
- Water (e.g. ad libitum): Tap water from an automatical watering system, ad libitum.
- Acclimation period: Between 5 and 11 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Average of 23 °C.
- Humidity (%): Average of 46 %.
- Air changes (per hr): 12 per hour.
- Photoperiod (hrs dark / hrs light): Artificial light from 6 a.m. to 6 p.m.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 10 mL per kg body weight.

Doses:

200 mg/kg body weight (males)
200 mg/kg body weight (females)
2000 mg/kg body weight (males)
500 mg/kg body weight (males)

No. of animals per sex per dose:

three males and three females (200 mg/kg body weight)
three females (200 mg/kg body weight)
three males (2000 mg/kg body weight)
three males (500 mg/kg body weight)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: performed within the periods 0 - 0.5, 0.5 - 1, 1-2, 2 - 4 and 4 - 6 hours after the administration (p.a.) of the test substance and at least once a day for a total of 2 weeks. Observations included, but were not limited to changes of the skin, the fur, the eyes, the occurrence of secretions and excretions, autonomic activity, changes in gait, posture and the presence of convulsions.
- Frequency of weighing: body weights were determined before administration, 7 days p.a. and 14 days p.a.
- Necropsy of survivors performed: yes

Results and discussion

Preliminary study:

not appicable

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Remarks:

oral

Effect level:

> 200 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

200 mg/kg body weight (males): 3/3 rats survived until the scheduled termination
200 mg/kg body weight (females): 3/3 rats survived until the scheduled termination.
2000 mg/kg body weight (males): 3/3 dies spontaneously within 20 minutes after the administration of the test substance.
500 mg/kg body weight (males): 3/3 rats died spontaneously within one day after the administration of the test substance.

Clinical signs:

other: All animals were affected. The findings, observed between the administration and 6 h p.a., were: - Autonomous nervous effects: Piloerection in all animals, increased salivation in nearly all males. - Central nervous effects: Convulsions, sedation and hype

Gross pathology:

2/3 spontaneously died males, dosed with 500 mg/kg body weight were affected. The post mortem findings were stomach ulcera and paleness of the gastic mucosa. In the other groups no abnormal findings were made.

Other findings:

There was no indication for a sex difference in the susceptibilty to the test substance.

Any other information on results incl. tables

Table 2: Synopsis of the results

Dose (mg/kg)	Sex	Animal No.	Number of animals
			exposed	affected	dead
200	m	21 - 23	3	3	0
200	f	26 - 28	3	3	0
2000	m	31 - 33	3	3	3
500	m	41 - 43	3	3	3

Table 3: Time of death

Dose (mg/kg)	Sex	Animal No.	Time of death (p.a.)
200	m	21 - 23	Animals survived
200	f	26 - 28	Animals survived
2000	m	31	20 minutes
		32	< 20 minutes
		33	< 20 minutes
500	m	41	< 4 hours
		42	< 2 hours
		43	< 1 day

Table 4: Body weights and body weight gain (Individual data, mean and standard deviation sd).

Dose (mg/kg) Sex	Animal No.	Body weight (g)				Body weight gain
		Before administration	7 days p.a.	14 days p.a.	death	0 - 7 days p.a.	7 - 14 days p.a.
200 m	21	203	261	293	-	58	32
	22	195	243	282	-	48	39
	23	189	238	283	-	49	45
	mean	196	247	286	-	52	39
	SD	7	12	6	-	6	7
200 f	11	192	226	232	-	34	6
	12	194	225	231	-	31	6
	13	186	203	228	-	17	25
	mean	191	218	230	-	27	12
	SD	4	13	2	-	9	11
2000 m	31	239	a)	a)	-	a)	a)
	32	246	a)	a)	-	a)	a)
	33	239	a)	a)	-	a)	a)
	mean	241	-	-	-	-	-
	SD	4	-	-	-	-	-
500 m	41	208	a)	a)	-	a)	a)
	42	214	a)	a)	-	a)	a)
	43	216	a)	a)	-	a)	a)
	mean	213	-	-	-	-	-
	SD	4	-	-	-	-	-

a) Animal died spontaneously

Table 5: Clinical observations. A grade of severity was recorded where applicable (low - medium - high).

Findings	Dose (mg/kg), sex	No. of the affected animal	Observation time (p.a.) first last	Maximum grade of severity
normal at any time	200 m	None	- / -	-
	200 f	None	- / -	-
	2000 m	None	- / -	-
	500 m	None	- / -	-
complete / incomplete eyelid closure	200 m	21	1 h / 2 h	-
		22	2 h / 4 h	-
		23	2 h / 2 h	-
	200 f	26	4 h / 6 h	-
		28	4 h / 4h	-
chromodacryorrhoea	500 m	*43	6 h / 6 h	low
piloerection	200 m	21	2 h / 6 h	low
		22	2 h / 6 h	low
		23	2 h / 6 h	low
	200 f	26	1 h / 6 h	low
		27	1 h / 6 h	low
		28	1 h / 6 h	low
	500 m	*41	0.5 h / 2 h	low
		*42	0.5 h / 1 h	low
		*43	0.5 h / 6 h	low
increased salivation	2000 m	*31	0.5 h / 0.5 h*	medium
		*32	0.5 h / 0.5 h*	medium
		*33	0.5 h / 0.5 h*	medium
	500 m	*42	1 h / 1 h*	low
		*43	2 h / 6 h*	low
abnormal posture	2000 m	*31	0.5 h / 0.5 h*	-
		*32	0.5 h / 0.5 h*	-
		*33	0.5 h / 0.5 h*	-
tonic convulsions	500 m	*42	0.5 h / 1 h*	-
epileptiform convulsions	2000 m	*31	0.5 h / 0.5 h*	high
		*32	0.5 h / 0.5 h*	high
		*33	0.5 h / 0.5 h*	high
hyperalgesia	2000 m	*32	0.5 h / 0.5 h*	-
	500 m	*33	0.5 h / 0.5 h*	-
		*42	1 h / 1 h*	low
sedation	500 m	*41	0.5 h / 2 h*	low
		*42	0.5 h / 1 h*	medium
		*43	0.5 h / 6 h*	medium

*: animal died spontaneously / finding lasted till death

Table 6: Necropsy Findings. Number examined: 9 males ans 3 females.

System Organ, finding	Dose (mg/kg)	Sex	Nos. of the affected animals
No findings	200	m	21, 22, 23
	200	f	26, 27, 28
	2000	m	31, 32, 33
	500	m	41
Alimentary System Glandular stomach, mucosa, ulcera	500	m	42
Glandular stomach, mucosa, pale	500	m	43

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

4-tert-Butylbenzonitrile caused effects on the autonomous and the central nervous system and sings of gerneral malaise at doses of 2000 and 500 mg/kg body weight, leading eventually to a 100 % mortality. A dose of 200 mg/kg body weight was suvived with only a few signs of reduced well-being.
The LD50 (oral) of 4-tert-Butylbenonitrile is therefore estimated to be highr than 200 mg and less than 500 mg per kg body weight in rats.
According to EC-Guideline, the test substance 4-tert-Butylbenzonitrile should be classified as harmfull if swallowed.

Executive summary:

In an acute oral toxicity study with rats (according to OECD 423 "acute toxic class method") the test substance caused effects on the autonomous and the central nervous system and signs of general malaise at the doses of 2000 and 500 mg/kg body weight, leading eventually to a 100 % mortality. A dose of 200 mg/kg body weight was survived with only a few signs of reduced well-being.

The LD₅₀ (oral) of 4-tert-Butylbenzonitrile is estimated to be higher than 200 mg and less than 500 mg per kg body weight in rats.

According to EC-guideline, the test substance 4-tert-Butylbenzonitrile should be classified as harmfull if swallowed.