Oxalonitrile

Endpoint summary

Description of key information

Ethanedinitrile is not skin and eye irritant (cause eye wiping, not damage).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because an acute toxicity study by the dermal route does not indicate skin irritation up to the relevant limit dose level (2 000 mg/kg body weight)

Reference 2

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

Four male albino rabbits whose weights averaged 4.5 pounds were closely clipped of their fur, restrained in a wooden stock, and placed in the chamber. An especially designed door, through which the rabbits heads extended into glass jarsmaintained under positive air pressure, prevented the rabbits from breathing cyanogen while their bodies were being exposed and also made observation of the heads of the rabbits possible. The bodies of the rabbits were exposed to ethanedinitrile concentration of 10,000 ppm for a period of 8 hours.

GLP compliance:

no

Specific details on test material used for the study:

Ethanedinitrile ≥ 99.5 %

Species:

rabbit

Strain:

not specified

Remarks:

male albino rabbits

Details on test animals or test system and environmental conditions:

Four male albino rabbits whose weights averaged 4.5 pounds were closely clipped of their fur, restrained in a wooden stock, and placed in the chamber. An especially designed door, through which the rabbits heads extended into glass jarsmaintained under positive air pressure, prevented the rabbits from breathing cyanogen while their bodies were being exposed and also made observation of the heads of the rabbits possible. The bodies of the rabbits were exposed to ethanedinitrile concentration of 10,000 ppm for a period of 8 hours.

Type of coverage:

open

Preparation of test site:

clipped

Vehicle:

other: air

Controls:

no

Amount / concentration applied:

10,000 ppm

Duration of treatment / exposure:

8 hours

Observation period:

8 hours

Number of animals:

4

Details on study design:

Four male albino rabbits whose weights averaged 4.5 pounds were closely clipped of their fur, restrained in a wooden stock, and placed in the chamber. An especially designed door, through which the rabbits heads extended into glass jars maintained under positive air pressure, prevented the rabbits from breathing cyanogen while their bodies were being exposed and also made observation of the heads of the rabbits possible. The bodies of the rabbits were exposed to ethanedinitrile concentration of 10,000 ppm for a period of 8 hours.

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

>= 0 <=

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

>= 0 <=

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Dermal exposure of rabbits to ethanedinitrile gas in an acute toxicity study indicates that ethanedinitrile is not a skin irritant. Dermal exposure of rabbits to 10,000 ppm (~21 g/m3) of ethanedinitrile for eight hours did not result in any clinical observations or macroscopic effects. None of the observation data meet requirements for labelling of EDN as a skin irritating substance, resulting from the requirements for substance classification according (ES) 1272/2008.

Other effects:

no other effects observed

Interpretation of results:

other: CLP criteria not met

Conclusions:

Dermal exposure of rabbits to ethanedinitrile gas in an acute toxicity study indicates that ethanedinitrile is not a skin irritant. Dermal exposure of rabbits to 10,000 ppm (~21 g/m3) of ethanedinitrile for eight hours did not result in any clinical observations or macroscopic effects.

Executive summary:

Dermal exposure of rabbits to ethanedinitrile gas in an acute toxicity study indicates that ethanedinitrile is not a skin irritant. Dermal exposure of rabbits to 10,000 ppm (~21 g/m3) of ethanedinitrile for eight hours did not result in any clinical observations or macroscopic effects. None of the observation data meet requirements for labelling of EDN as a skin irritating substance, resulting from the requirements for substance classification according (ES) 1272/2008.

Materials and Methods               

Test material                                    Ethanedinitrile (Cyanogen), (NCCN)

Specification                                    Ethanedinitrile gas

Purity                                                  99.5% (0.5%–nitrogen, chlorine, cyanogen chloride)    

 

Test Animals             Rat        

Strain                          Albino rat – strain not reported

Source                        Not reported

Sex                              Males only

Age/weight at study initiation  135 g (average)                                              

Number of animals per group  13 groups of six rats – six different concentrations, six different time periods and control

 

Administration/Exposure          Inhalation

Postexposure period                 14 days

Concentration of test substance                           

Nominal concentration: 0, 533, 537, 851, 851, 1054, 1066, 2115, 2111, 4207, 4223, 8508, 8571 mg/m³ (0, 250, 250, 400, 400, 500, 500, 1000, 1000, 2000, 2000, 4000 and 4000 ppm)

Type of exposure                           Whole body

Duration of exposure                   120, 60, 45, 30, 15, 7.5 and 0 minutes

Controls                                          Not reported

 

Results and Discussion

Clinical symptoms         asphyxiation, lacrimation, upper respiratory tract irritation, pink coloration of the noticeable skin, blinking eyes, rubbing of forepaws over eyes and snout, huddling together with inactivity, slow gasping, tearful eyes, yellow fluid dripping from nares and mouth, restless and panic type movements, accentuated and poorly coordinated motions, bright pink coloration of the skin, laboured breathing, gasping, tremors, sluggishness, prostration, shallow breathing, death

 

Pathology                          Not reported

 

LC50                                  23,400 ppm / t; t= exposure duration in min

See the Table 5.2.3-2 Effects of the Acute Inhalation Exposures of Ethanedinitrile upon Male Albino Rats and a Time-concentration Graph which are enclosed below.

 

Summary and conclusion

Rats were housed in wire mesh cages within the chamber and exposed to a total of six different concentrations of ethanedinitrile and six different time periods. Survivors were observed for 14 days after exposure. Body weight of rats was measured before exposure and after 14 days.

The present study showed that rats withstood 250 ppm of ethanedinitrile for 120 min with only partial mortality and 500 ppm for 30 min with no deaths. In addition, the capacity of the rats in this study to tolerate the excessive concentrations of 1,000 and 2,000 ppm of ethanedinitrile for periods of approximately 15 and 7.5 min, respectively, points toward a lower toxicity.

Assuming transformation of one molecule of ethanedinitrile to one molecule of hydrogen cyanide, following approximate LC values may be calculated for HCN (t = exposure duration in min):

LC0= 15,900 mg/m³/t

LC50= 25,850 mg/m³/t

LC100= 41,050 mg/m³/t

Non-guideline study; the study from 1960 is not in the GLP system, but the method used is comparable to methods standardised by EU Directive 440/2008. 

 

Table 5.2.3-2: Effects of the Acute Inhalation Exposures of Ethanedinitrile Upon Male Albino rats

 

Concentration ofEthanedinitrile		Average Temp. (°C)	Length of exposure (min)	Length build-up period (min)	Mortality ratio (dead/dosed)	Initial average weight of rats (g)	Average weight gain after 14 days (g)
(ppm)	(mg/m^3)
4000	8571	22.8	7.5	3.0	3/6	162	44
4000	8508	25.0	15	3.0	6/6	156	-
2000	4223	27.2	7.5	1.5	0/6	126	55
2000	4207	28.3	15	1.5	6/6	121	-
1000	2111	27.2	15	0.5	0/6	123	52
1000	2115	26.7	30	0.5	6/6	123	-
500	1066	24.4	30	0.3	0/6	134	49
500	1054	27.8	45	0.3	6/6	122	-
400	851	25.0	45	0.25	0/6	144	46
400	851	25.0	60	0.25	6/6	137	-
250	537	22.2	60	0.15	0/6	160	59
250	533	24.4	120	0.15	4/6	127	38
Control	-	-	-	-	0/6	167	53

Reference 3

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

Materials amd methods              

Ethanedinitrile (CN)2, subchronic (180 days) inhalation toxicity study.

Six months (6h/day, 5 days/week) inhalation exposure was conducted with ethanedinitrile gas using male rhesus monkeys (Macacca mulatta) and male albino rats (Charles River Strain). Fifteen monkeys and 90 rats were divided into three groups of 5 monkeys and 30 rats. One group, the Controls, was exposed to the air; the other two groups were exposed to ethanedinitrile concentrations of 11 or 25 ppm.

GLP compliance:

no

Species:

other: albino rat and rhesus monkey

Strain:

other: Macacca mulatta, Charles River Sprague-Dawley COBS

Details on test animals or test system and environmental conditions:

Source of animals: Charles River

Type of coverage:

open

Preparation of test site:

not specified

Vehicle:

other: air

Controls:

yes

Amount / concentration applied:

11 and 25 ppm

Duration of treatment / exposure:

180 days (6h/day, 5 days/week)

Observation period:

180 days
postexposure period 4 weeks

Number of animals:

rats: 30 per exposure group
monkeys: 5 per exposure group

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No irritation was observed during the 6 months exposure of rats and monkeys to ethanedinitrile.

Interpretation of results:

other: CLP criteria not met

Conclusions:

During the 6months whole body exposure to ethanedinitrile (11 and 25 ppm), no skin irritation was observed on rats and monkeys.

Executive summary:

During the 6 months whole body exposure to ethanedinitrile (11 and 25 ppm), no skin irritation was observed on rats and monkeys.

Materials and Methods               Ethanedinitrile (Cyanogen)

Specification                                    

Purity                                                  99% pure

Stability                                              Not stated

 

Test Animals                Rhesus monkey, albino rats

Strain                              Macacca mulatta, Charles River Sprague-Dawley COBS

Source                           Charles River

Sex                                  Male monkeys and rats

Age/weight at study initiation  Not stated                         

Number of animals per group  5 monkeys per treatment group

                                                              30 rats per treatment group

Control animals                               Yes

 

Administration/Exposure          Inhalation

Type of exposure                           Whole body

Exposure period                             180 days (6 h/day, 5 days/week)

Postexposure period                   14 days, 4 weeks or other

 

Concentration 

of test substance                           Nominal concentrations 0 ppm; 11 ppm; 25 ppm

                                                              Analytical concentrations ≤1 ppm; 11.2 ± 1.5 ppm; 25.3 ± 3.3 ppm

Controls                                             Sham exposed

Body weight                                     

Prior to the start of the study, prior to sacrifice, and at least monthly during exposures to verify growth in rats and deprivation maintenance in monkeys.

Examination                                     

Behavioral testing (only in monkeys), Clinical observations, Hematology, Clinical Chemistry, Pathology (gross necropsy and microscopic examination)

Observation                                     Daily

Food consumption                        No

Water consumption                      No

Behavioural testing                       1 day per week for 12 monkeys, and 5 days per week for 3 monkeys (one in each of the groups)

 

Haematology                                   

Parameters: hematocrit, haemoglobin concentration

number of animals: each monkey, 6 rats per exposure level

time points: monkey – 0 day, 30 days, 90 days, 180 days of exposure; rats –2 days, 5 days, 30days, 90 days, 180 days of exposure

Clinical Chemisty                            parameters: T3 and T4

                                                              number of animals: each monkey, 6 rats per exposure level

time points: monkey – 0 day, 30 days, 90 days, 180 days of exposure rats –2 days, 5 days, 30 days, 90 days, 180 days of exposure;

 

Organ weights                                 Yes; lungs

Gross and histopathology           all dose groups (2 days of exposure and again 5 days, 1 month, 3 months, 180 days – rats; 11 monkeys were similarly sacrificed immediately after the termination of exposures, 3 monkeys – 4 weeks later)

organs: thyroid, liver, kidneys, spleen, heart, lungs, bone marrow, cerebellum, cerebrum

Statistics                                            ANOVA, non-parametric tests

Others                                                ECG in monkeys before exposures and after the last exposure

 

Results and Discussion

Clinical symptoms                         

Behavioral testing                          There was an increase in response rate in all three groups during the exposure period compared to the baseline period. The mean increase was 20%, 14%, 145% in T-CO, T-11 and T-25 subjects, respectively. The rate changes for each group were evaluated statistically by mean of a randomization test for matched pair. The increase in response rate in the T‑25 group was marginally significant. The probability that the rate increases in the T-CO and T-11 groups could have occurred by chance was greater than 0.10

Mortality                                           One (control) monkey died near the start of the exposures from causes unrelated to the experiment; 3 rats (control) died, 1 (11 ppm), 4 (25 ppm) – was not significantly different from change

Body weight                                     Mean body weights of rats exposed to ethanedinitrile at 25 ppm was significantly depressed compared to control

 

Water consumption

and compound intake                  Not reported

 

Haematology                                   No consistent effects

Clinical chemistry                           No effects on T3 uptake and T4 concentration

Urinalysis                                         Not reported

               

Gross and histopathology           No effects

Organ weight                                   No effects in rats; lungs from control monkeys contained more moisture than lungs from monkeys exposed to ethanedinitrile gas

Summary and conclusion

Materials amd methods              

Ethanedinitrile (CN)₂, subchronic (180 days) inhalation toxicity study.

Six months (6h/day, 5 days/week) inhalation exposure was conducted with ethanedinitrile gas using male rhesus monkeys (Macacca mulatta) and male albino rats (Charles River Strain). Fifteen monkeys and 90 rats were divided into three groups of 5 monkeys and 30 rats. One group, the Controls, was exposed to the air; the other two groups were exposed to ethanedinitrile concentrations of 11 or 25 ppm.

 

Results and discussion

At the end of the 6 months exposure, there were no differences in hematologic or clinical chemistry (T3, T4) parameters attributable to the inhalation exposure to ethanedinitrile. The electrocardiograms, and gross pathologic and histopatologic examinations of the test animals were normal when compared with the control animals. Total lung moisture content was significantly lower in monkeys exposed to either 11 ppm or 25 ppm ethanedinitrile than in control animals; no differences were found in rats. Body weights were significantly lower in rats exposed to 25 ppm than in controls.

There was a doubling of the rate of responding on a variable interval 2.9 min schedule of reinforcement in monkeys exposed to 25 ppm ethanedinitrile, and increases were also seen in the monkeys exposed to 11 and 0 ppm; the increases were transitory as the rate returned to control levels before exposures were terminated.

 

Conclusion

Subchronic 25 ppm ethanedinitrile exposures are marginally toxic, but the evidence on 11 ppm does not support a similar conclusion.

LO(A)EL                                              25 ppm

NO(A)EL                                             11 ppm

 

Table 5.5.1-2: Results of Behavioral testing

Operant Response Rate (mean number of responses/hour)
Group		Animal number		baseline		exposure
T – CO		2		491		818
		8		1064		1036
		15		1091		954
		18		109		436
		Mean		689		811
T – 11		2		327		791
		4		1064		1391
		5		600		1036
		11		191		464
		16		1745		845
		Mean		785		905
T –25		1		627		1254
		6		245		1173
		10		191		409
		12		191		464
		17		273		355
		Mean		305		731

 

 

 

Table 5.5.1-3: Results of Haematology and Clinical chemistry

Rats							Monkeys
Day
group		2		5		30		90		180		0		30		90		180
Hemoglobin concentration (g/100 mL)
T–CO		13.7		15.8		15.5		14.6		14.4		14.0		13.2		14.0		13.7
T–11		14.5		16.1		16.5		14.4		15.3		13.5		12.1		13.2		12.8
T–25		14.4		15.8		15.2		15.2		15.3		13.3		12.0		12.9		13.3
Hematocrit Value (%)
T–CO		44		48		48		45		38		43		39		43		41
T–11		46		49		48		44		39		42		36		41		39
T–25		47		50		46		45		39		40		36		40		40
T3% Uptake
T–CO		47.4		46.9		45.9		48.4		41.2		25.8		22.3		27.9		24.8
T–11		47.7		46.5		45.8		48.6		44.2		33.6		28.7		31.5		30.4
T–25		47.8		46.4		43.6		47.0		41.6		32.0		24.4		29.9		26.2
T4mg/100 mL
T–CO		5.6		5.3		5.2		7.8		3.4		7.5		7.7		7.2		10.4
T–11		5.6		3.9		4.3		7.1		5.1		6.4		6.4		5.5		7.7
T–25		4.6		3.8		4.6		8.4		4.3		8.4		7.8		9.2		9.5

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Justification for classification or non-classification

CLP criteria not met