Cyanoguanidine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January - November 1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

no information on body weight changes, no raw data reported

GLP compliance:

no

Test type:

acute toxic class method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cyanoguanidine

EC Number:

207-312-8

EC Name:

Cyanoguanidine

Cas Number:

461-58-5

Molecular formula:

C2H4N4

IUPAC Name:

1-cyanoguanidine

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Age at study initiation: 8 weeks
- Weight at study initiation: males ca. 195 g, females ca. 131 g
- Diet (e.g. ad libitum): stock diet
- Water (e.g. ad libitum): tap water
- Housing: wire screen cages
- observation period: 14 days

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure chamber volume: 1.5 m³
- Method of holding animals in test chamber: animals were housed in wire screen cages
- Source and rate of air: filtered air, flow rate: 1m³/h
- System of generating particulates/aerosols: the powder was continuously dispersed in air by means of a "Wright" Dust Feed Mechanism at a rate of 6g/m³


TEST ATMOSPHERE
- Brief description of analytical method used: particle size determinations and counts were carried out in samples taken from the atmosphere in the chamber with a cascade impactor
- Particle size distribution: 99 % particke size range of 0.6 - 2.4 µm
- Concentration in air: 259 mg/m³ (maximum attainable concentration)
- Determination of concentration: gravimetrically by passing measured amounts of chamber air through glass fibre filters

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Determination of concentration: gravimetrically by passing measured amounts of chamber air through glass fibre filters

Duration of exposure:

4 h

Concentrations:

259 mg/m³ (maximum attainable concentration)

No. of animals per sex per dose:

Five

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: no data
- Necropsy of survivors performed: no data
- Other examinations performed: mortality, signs of intoxication

Statistics:

No data.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC0

Effect level:

> 259 mg/m³ air

Exp. duration:

4 h

Mortality:

Mortality did not ocur either during exposure or during the subsequent 14-day observation period.

Clinical signs:

other: Signs of intoxication did not ocur either during exposure or during the subsequent 14-day observation period.

Body weight:

No data.

Gross pathology:

No data.

Other findings:

Other observations:
During the first quarter of an hour of the exposure period the rats showed slight restlessness; during the remaining part of the exposure period they were asleep.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

As a four-hour exposure of rats to a dispersion of Dicyandiamid at a maximum attainable concentration of 259 mg/m³ of air did not cause mortality or any noticeable deleterious effects, it can be concluded that the powder has a very low acute inhalation toxicity. It is not likely, therefore, that the substance at concentrations up to 259 mg/m³ will present acute inhalation hazard to man.

Executive summary:

The aim of this study was to determine the 4 -hour LC₅₀ value of Dicyandiamid. Each five male and female rats were exposed to the test atmosphere generated by dispersing the powder continuously in air by means of a "Wright" Dust Feed Mechanism at a rate of 6 g/m³ for four hours (whole-body exposure) at an actual concentration of 259 mg/m³ (maximum attainable concentration).

The animals were observed for mortality and signs of intixication during exposure and daily thereafter for 14 days. Particle determination and counts in air samples revealed a 99 % particle size range of 0.6 - 2.4 µm.

The four-hour exposure of the rats to a dispersion of Dicyandiamid at a maximum attainable concentration of 259 mg/m³ of air did not cause mortality or any noticeable deleterious effects, it can be concluded that the powder has a very low acute inhalation toxicity. It is not likely, therefore, that the substance at concentrations up to 259 mg/m³ will present acute inhalation hazard to man.

The acute inhalation (4 hour) LC₅₀ for Dicyandiamid in the rat is higher than 259 mg/m³.