Cyanamide

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Report date:

1973

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Applied volume was not constant. Body weight determination only at day 1 and at termination.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Cyanamide

EC Number:

206-992-3

EC Name:

Cyanamide

Cas Number:

420-04-2

Molecular formula:

CH2N2

IUPAC Name:

cyanamide

Test material form:

other: aqueous solution

Details on test material:

- Name of test material: SKW Cyanamid L500 (supplied as 50 % aqueous solution)
- Appearance: Clear liquid

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

From the following 5% (v/v) aqueous dilutions: 4, 5, 6, 7 mL/kg bw, the following dose test substance were applied respectively: 0.2, 0.25, 0.3, 0.35 mL/kg bw.

Doses:

100, 125, 150, 175 mg/kg bw of cyanamide

No. of animals per sex per dose:

5 animals per sex per dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Only at day 1 and at termination
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Results and discussion

Preliminary study:

The dose selection was based upon a range-finding study using groups of one to five male and female rat/test group: undiluted technical cyanamide was dosed at 1.0, 2.0 or 5.0 mL/kg bw followed by dosages of 4.0, 6.0 and 8.0 mL of a 10 % (v/v) aqueous dilution (corresponding to 0.4, 0.6 and 0.8 mL test substance/kg bw). Mortality was seen in all rats dosed with 0.6 mL test substance/kg bw or more shortly after dosing with signs of convulsion. All females rats dosed with 0.4 mL/kg bw survived while all males of this dose group died. Clinical signs were lachrymation, apnoea and coma.

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

142 mg/kg bw

Based on:

act. ingr.

Mortality:

Mortality was observed in all dose levels with a higher incidence in males and occurred mainly during the first day between 6 and 24 hours after dosing. One male died on the third post treatment day.

Clinical signs:

other: The only clinical symptoms were convulsions in rats, that died. Rats, that survived, had no significant changes at necropsy.

Gross pathology:

Rats, that survived, had no significant changes at necropsy.

Other findings:

No other findings

Any other information on results incl. tables

Males			Females
Dose	Mortality	Time of death	Dose	Mortality	Time of death
100 mg/kg	1/5	Day 1	100 mg/kg	0/5	-
125 mg/kg	4/5	Day 1	125 mg/kg	0/5	-
150 mg/kg	5/5	Day 1 and 3	150 mg/kg	2/5	Day 1
175 mg/kg	5/5	Day 1	175 mg/kg	1/5	Day 1

Applicant's summary and conclusion

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The acute oral LD50 of pure active substance cyanamide in rats was estimated to be 142 mg/kg bw for the sexes combined.

Executive summary:

Cyanamid L500 (supplied as 50 % aqueous solution) was orally administered in a 5 % (v/v) aqueous dilution to four groups of Albino Wistar rats (source not mentioned), each group with five males and five females, at dose levels of 100 to 175 mg/kg bw by gavage.

The animals were observed for treatment-related effects during the first 4 hours and for a subsequent 14-day observation period.

Mortality was observed in all dose levels with a higher incidence in males and occurred mainly during the first day between 6 and 24 hours after dosing. One male died on the third post treatment day.The only clinical symptoms were convulsions in rats, that died. Rats, that survived, had no significant changes at necropsy.

The acute oral LD50 of pure active substance cyanamide in rats was estimated to be 142 mg/kg bw for male and female rats (ca.300 mg/kg bw of the 50% aquous solution).