Methacrylonitrile

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

no data

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methacrylonitrile

EC Number:

204-817-5

EC Name:

Methacrylonitrile

Cas Number:

126-98-7

Molecular formula:

C4H5N

IUPAC Name:

2-methylprop-2-enenitrile

Details on test material:

- Name of test material (as cited in study report): 2-methyl-2-propenenitrile (MAN)
- Substance type: Colourless liquid at room temperature
- Physical state: Liquid
- Analytical purity: 99%.
- Stability under test conditions: Tested by the provider of the test material
- Storage condition of test material: In a hermetic container, shield from the light at 4 - 10 degrees Centigrade

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (Japan) Ltd, Atsugi, Japan
- Age at study initiation: 5 weeks old
- Weight at study initiation: Mean of 146.4 g (140 to 153 g) for males, mean of 117.5 g (110 to 125 g) for females
- Housing: The animals were housed individually in metal wire netting cages
- Diet (e.g. ad libitum): CRF-1 (Lot No. of 980904, 981209, Oriental Yeast Co., Ltd.), ad libitum. The diet was analysed and were considered not to contain any contaminants that would exceed the standard levels of contaminants
- Water (e.g. ad libitum): Mains water (Sapporo-shi, Hokkaido, Japan), ad libitum. The mains water was analysed and were considered not to contain any contaminants that would exceed the standard levels of contaminants
- Acclimation period: 7 days.

ENVIRONMENTAL CONDITIONS
- Temperature: 21 to 23 degrees Centigrade
- Humidity: 52 to 59 %.
- Air changes (per hr): 10 to 15 changes per hour.
- Photoperiod (hrs dark / hrs light): Twelve hours continuous light (08:00 to 20:00) and 12 hours darkness.


IN-LIFE DATES: From: Day 0 Up To: Day 14

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

olive oil

Details on oral exposure:

VEHICLE
- Amount of vehicle (if gavage): 5 mL/kg
- Lot/batch no. (if required): 807089 (Yakuhan Pharmaceutical Co., Ltd., Japan)

MAXIMUM DOSE VOLUME APPLIED:
100 mg/kg for males, 120 mg/kg for females

Doses:

Zero, 50, 60, 70, 85 and 100 mg/kg bw for males
Zero, 60, 70, 85, 100 and 120 mg/kg bw for females

No. of animals per sex per dose:

5 males and 5 females per dose level

Control animals:

yes

Details on study design:

- Duration of observation period following administration: Day zero (the day of dosing) up to Day 14
- Frequency of observations and weighing: Deaths, cage side observation and behaviour were recorded continuously on Day 0 to 1 hour after dosing, then 2, 3, 4, 5 and 6 hours and then daily for 14 days
- Necropsy: Dead animals during the study period and surviving animals. macroscopic observation of the organs (brain, liver, kidneys, spleen, heart, lung, stomach, duodenum, celenteron, ileum, cecum, colon, intestinum, testes, epididymides and ovaries)
- Other examinations performed: body weight,histopathology

Statistics:

Mortality data was used for the estimation of LD50 and 95 % CI by the probit method

Results and discussion

Preliminary study:

Mortality 1/3 males at 60 mg/kg, 2/3 males at 70 mg/kg, and 3/3 at and above 85 mg/kg; 2/3 females at 70, 85 and 100 mg/kg, 3/3 at and above 150 mg/kg

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LD50

Effect level:

64 mg/kg bw

Based on:

test mat.

95% CL:

>= 49 - <= 76

Effect levels 2

Sex:

female

Dose descriptor:

LD50

Effect level:

73 mg/kg bw

Based on:

test mat.

95% CL:

>= 49 - <= 87

Mortality:

See Table 2 (below) for the mortality and LD50

Clinical signs:

other: Treatment-related effects such as decrease in locomotor activity, prone/side position, hyperpnea, clonic convulsion, salivation, diarrhaea and soiling of perigenital, perianal, and perioral fur were observed in both sexes (see Table 3, below)

Gross pathology:

Postmortem findings included a dark red patch in the mucosa of the glandular stomach, pale red discoloration in small intestine, bright orange discoloration and dilation in right atrium were observed in both sexes (see Table 6, below).

Dark red patch in mucosa in glandular stomach, pale red discoloration in small intestine were considered to be caused by the corrosive nature of the test substance. Bright orange discoloration and hyperpnea (as clinical sign of dilation in right atrium) were attributed to effects of the test substance to the lungs and breathing, as most of the test substance would be excreted to the air in other available oral gavage studies in rats. Bright orange discoloration might have been related to the effects in haematological parameters such as decreases in red blood cells and haemoglobin (haemolytic changes) in the past studies. No mode of action could have been identified between dilation in right atrium and effects in the lungs.

Other findings:

No data

Any other information on results incl. tables

Table 2: Mortality

Males
Dose (mg/kg)	0	50	60	70	85	100
Number of animals	5	5	5	5	5	5
Number of deaths	0	1	2	3	4	5
Females
Dose (mg/kg)	0	60	70	85	100	120
Number of animals	5	5	5	5	5	5
Number of deaths	0	2	1	4	4	5

Table 3: General appearance of rats in acute oral toxicity test of 2-methyl-2-propenenitrile (MAN)

 

Item	Male						Female
	MAN (mg/kg)						MAN (mg/kg)
	Control	50	60	70	85	100	Control	60	70	85	100	120
Administration day     No. of animals examined	5	5	5	5	5	5	5	5	5	5	5	5
No abnormal findings	5^a	0	0	0	0	0	5	2	0	0	0	0
Decrease in locomotor activity	0	4	3	4	2	2	0	2	5	5	3	5
Prone/side position	0	5	4	3	5	5	0	1	1	4	3	4
Hyperpnoea	0	5	5	5	5	5	0	3	5	5	4	5
Colonic convulsion	0	0	0	0	0	1	0	1	0	0	0	0
Salivation	0	0	1	0	0	1	0	0	0	0	2	0
Diarrhoea	0	0	0	1	0	0	0	0	1	0	0	0
Soiled perioral fur	0	0	0	1	1	0	0	0	0	0	0	2
Soiled perigenital fur	0	0	0	1	0	0	0	0	1	3	0	2
Soiled perianal fur	0	1	0	1	1	0	0	0	0	0	0	0
Dead	0	1	2	2	4	5	0	1	1	4	3	2
1-14 days after administration     No. of animals examined	5	4	3	3	1	0	5	4	4	1	2	3
No abnormal findings	5	4	3	2	1	-^b	5	3	3	1	1	0
Soiled perigenital fur	0	0	0	0	0	-	0	0	1	0	0	2
Dead	0	0	0	1	0	-	0	1	0	0	1	3

 a: Values are no. of animals with findings

 b: - = blank value

Table 4: Bodyweight changes of male rats in acute toxicity test of 2-methyl-2-propenenitrile (MAN)

 

Group	No. of animals	Day after administration							Bodyweight gain
		0	1	3	5	7	10	14	Day 0-14	%^a
Control	5	124.6^b 3.4	146.8 3.3	171.8 5.8	191.0 5.3	209.2 5.5	237.4 7.8	273.4 11.0	148.8 10.9	119.516 9.688
MAN 50 mg/kg	5	123.6 1.5	(4)^c 141.3 4.7	(4) 166.0 3.5	(4) 188.3 5.1	(4) 207.8 7.3	(4) 237.5 7.6	(4) 276.3 11.2	(4) 153.0 10.2	(4) 124.108 7.487
MAN 60 mg/kg	5	124.0 3.8	(3) 141.7 4.9	(3) 171.0 2.6	(3) 193.7 2.5	(3) 214.0 2.6	(3) 244.7 3.1	(3) 285.7 8.6	(3) 159.7 7.8	(3) 126.790 7.135
MAN 70 mg/kg	5	122.2 3.0	(2) 136.5 9.2	(2) 168.0 5.7	(2) 190.0 8.5	(2) 212.0 4.2	(2) 244.0 7.1	(2) 287.5 7.8	(2) 167.5 7.8	(2) 139.585 6.484
MAN 85 mg/kg	5	124.0 5.2	(1) 138.0	(1) 173.0	(1) 193.0	(1) 213.0	(1) 241.0	(1) 273.0	(1) 146.0	(1) 114.960
MAN 100 mg/kg	5	124.6 3.4	-^d	-	-	-	-	-	-	-

 a: (Bodyweight gain / bodyweight on day 0) x 100

 b: Values are means and S.D. there under, expressed in grams

 c: Values in parentheses are no. of animals examined

 d: - = blank value

Table 5: Bodyweight changes of female rats in acute toxicity test of 2-methyl-2-propenenitrile (MAN)

 

Group	No. of animals	Day after administration							Bodyweight gain
		0	1	3	5	7	10	14	Day 0-14	%^a
Control	5	98.8^b 4.0	117.6 4.6	134.8 6.4	144.8 5.3	155.0 5.4	165.6 9.2	180.2 8.8	81.4 7.8	82.486 8.184
MAN 60 mg/kg	5	100.0 3.9	(3)^c 111.3 5.5	(3) 136.0 2.0	(3) 149.0 5.6	(3) 161.3 4.5	(3) 172.0 5.6	(3) 184.0 6.6	(3) 84.7 4.5	(3) 85.197 2.830
MAN 70 mg/kg	5	98.2 4.8	(4) 100.8* 7.9	(4) 130.8 11.4	(4) 144.8 9.0	(4) 158.0 12.6	(4) 171.0 13.3	(4) 184.5 13.1	(4) 86.3 9.9	(4) 87.828 9.821
MAN 85 mg/kg	5	98.6 2.7	(1) 89.0	(1) 124.0	(1) 143.0	(1) 146.0	(1) 157.0	(1) 171.0	(1) 72.0	(1) 72.730
MAN 100 mg/kg	5	98.4 3.8	(1) 112.0	(1) 137.0	(1) 148.0	(1) 163.0	(1) 168.0	(1) 197.0	(1) 94.0	(1) 91.260
MAN 120 mg/kg	5	98.8 4.1	-^d	-	-	-	-	-	-	-

 a: (Bodyweight gain / bodyweight on day 0) x 100

 b: Values are means and S.D. there under, expressed in grams

 c: Values in parentheses are no. of animals examined

 d: - = blank value

 *: Differs from control, p≤0.05

Table 6: Gross findings of rats in acute oral toxicity test of 2-methyl-2-propenenitrile (MAN)

 

Item	Male						Female
	MAN (mg/kg)						MAN (mg/kg)
	Control	50	60	70	85	100	Control	60	70	85	100	120
Total no. of animals examined	5	5	5	5	5	5	5	5	5	5	5	5
Findings of dead animals No. of animals examined	0	1	2	3	4	5	0	2	1	4	4	5
Organ: Findings
Lung: Bright orange discolouration	-^a	1^b	2	3	2	4	-	1	1	3	3	2
Glandular stomach: Dark red patch, mucosa	-	0	2	3	2	1	-	0	1	3	3	5
Small intestine: Pale red discolouration	-	1	0	0	1	3	-	0	1	0	1	1
Heart: Dilation, right atrium	-	1	2	3	4	3	-	2	1	3	4	4
Findings of surviving animals No. of animals examined	5	4	3	2	1	0	5	3	4	1	1	0
Abnormal findings	0	0	0	0	0	-	0	0	0	0	0	-

 a: - = blank value

 b: Values are no. of animals with findings

Applicant's summary and conclusion

Conclusions:

As a result of the acute oral study in rats, decrease in locomotor activity, prone/side position, hyperpnea and deaths were observed. The acute oral lethal dose (LD50) of the test material in the rat was 64 mg/kg bodyweight (95%CI 49 - 76) in males and 73 mg/kg bodyweight (95%CI 49 - 87) in females under the test condition.