Cyclohex-1,2-ylenediamine

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From 18 OCT 1988 to 3 NOV 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

GLP compliance:

yes

Remarks:

according to EPA GLP Regulations (40 CFR 792)

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cyclohex-1,2-ylenediamine

EC Number:

211-776-7

EC Name:

Cyclohex-1,2-ylenediamine

Cas Number:

694-83-7

Molecular formula:

C6H14N2

IUPAC Name:

cyclohexane-1,2-diamine

Details on test material:

- Name of test material (as cited in study report): 1,2-Diaminocyclohexane, DCH
- Physical state: liquid
- Analytical purity:
three different purities were tested:
Study period A)
89% DCH (H-17448)
98% DCH (H-17447)
Study period B)
93% DCH (H-18428)
98% DCH (H-18429)
- Stability under test conditions: test material was expected to be stable under the conditions of the study

Test animals

Species:

rat

Strain:

other: Crl:CD*BR

Sex:

male

Administration / exposure

Route of administration:

other: inhalation of an aerosol/vapour mixture

Type of inhalation exposure:

nose only

Vehicle:

other: test period A: only air or air and nitrogen; test period B: air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: glass exposure chambers
- Exposure chamber volume: 29 or 28 litres
- Method of holding animals in test chamber:restrainer
- System of generating particulates/aerosols:
Test period A: Round bottom flask
Aerosol and vapour atmospheres of DCH were generated by metering the test material with a Harvard Model 975 Compact Infusion Pump to an
Instatherm Flask heated to 124-149°C (total range for three exposures). In the only exposure with 89% DCH and in one exposure with 98% DCH, air
introduced at the flask swept the aerosol/vapour mixture of DCH into a glass transfer tube, where dilution air was added. The generation system for the second exposure to 98% DCH was identical to the previously mentioned system, except that nitrogen swept the DCH aerosol/vapour mixture to the transfer tube instead of air. The DCH mixture then discharged directly into a 38-liter cylindrical glass exposure chamber and was dispersed with a
baffle to promote uniform chamber distribution. Chamber concentrations of DCH were controlled by varying the test Material feed rates into the flask.

Test period B: J-Tube
Aerosol and vapour atmospheres of DCH were generated by pumping DCH with a Harvard Compact Infusion Pump to a glass J-tube containing 6 mm glass beads. A Goodburn Model T2 Electronic Torch heated the air entering the J-tube. The torch temperature was controlled by an Omega Model CS-6001-J temperature controller. The temperature entering the J-tube ranged from 60-82°C, and the temperature exiting the J-tube ranged from 42-62°C. The DCH aerosol/vapour mixture then discharged directly into a 29-liter cylindrical glass exposure chamber and was dispersed with a baffle to
promote uniform chamber distribution. Chamber concentrations of DCH were controlled by varying the test material feed rates into the J-tube.

- Method of particle size determination: with a Sierra Series 210 Cascade Impactor
- Treatment of exhaust air: Chamber atmospheres were exhausted through an emissions-abatement train consisting of a cold trap, and a MSA cartridge filter prior to discharge into a fume hood.

TEST ATMOSPHERE
- Brief description of analytical method used: The atmospheric particulate concentraticn of DCH was calculated from the pre- and post-sampling filter weights which were determined with a Cahn 26 Automatic Electrobalance. Airborne particle size (Mass median aerodynamic diameter and percent of mass less than 10 micrometers aerodynamic diameter) was determined with a Sierra Series 210 cascade impactor.
- Samples taken from breathing zone: yes

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

mean total
Study period A)
89% DCH: 3.09 mg/L
98% DCH: 4.73 mg/L / 3.34 mg/L (using nitrogen as vehicle)
Study period B)
93% DCH: 3.3 mg/L
98% DCH: 3.23 mg/L

No. of animals per sex per dose:

Study period A): 10 males
Study period B): 6 males

Control animals:

no

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

other: LC lo

Effect level:

3.2 mg/L air (analytical)

Based on:

test mat.

Remarks:

98% DCH

Exp. duration:

4 h

Any other information on results incl. tables

Groups of either 6 (test period B) or 10 (test period A) male Crl:CD•BR rats were exposed for single 4-hour periods to atmospheres containing 1,2-Diaminocyclohexane (DCH) vapour and aerosol in air. Three different purities of DCH were tested: 89%, 93%, and 98% .Test atmospheres of DCH were generated by evaporation of the heated test material under air or nitrogen. The vapour portion of the atmosphere was analysed using gas chromatography and the aerosol portion was measured gravimetrically. After the exposures, rats were weighed and observed for clinical signs of toxicity during a 14 or 15 day recovery period. Rats exposed to DCH showed slight to severe weight loss after exposure, and resumed a normal weight-gain rate from 2 to 4 days after exposure.

Under the conditions of this test, the median lethal concentration could not be determined, however the approximate lethal concentration for 98% DCH was determined to be 3.2 mg/1 (combined aerosol and vapour mean concentrations).

One of 6 rats in this exposure group was found dead on the 4th day after the exposure. No deaths occurred in exposures using either 89% or 93% DCH at concentrations greater than 3 mg/l. This material is considered to be low to moderate in toxicity on an acute Inhalation basis.

Exposure conditions and mortality

Mean total Conc. [mg/L] (SD) (a)	Particle size - MMD [micrometre] (b)	Particle size - [%] < 10 micrometres (c)	Mortality (#deaths/#exposed)	Test material	mean % Aerosol / % Vapour
4.73 (1.75)	3.4	88	0/10	98% DCH (H-17447) e	83/17
3.34 (0.314)	5.6	81	0/10	98% DCH (H-17447) e	77/23
3.09 (0.428)	4.0	84	0/10	89% DCH (H-17448) e, f	71/29
3.3 (0.667)	7.6	65	0/6	93% DCH (H-18428) g	43/57
3.23 (0.67)	9.5	55	1/6	98% DCH (H-18429) g	37/63
a. values shown represent the mean of several samples drawn during the exposure period, standard deviation (S.D.).        b. Mass median aerodynamic diameter c. Percent by weight of particles with aerodynamic diameter less than 10 micrometres. e. test period A, DCH aerosol/vapour generated by flash evaporation from round bottom flask. f. nitrogen was used in this exposure as the generation gas instead of air g. test period B, DCH aerosol/vapour generated by evaporation using J-tube

Test period A:

Immediately following exposures, rats from all groups-showed, red nasal and ocular discharges, hunched posture, and compound-stained faces., In addition, rats exposed ,to the highest total concentration had partially closed eyes. During the recovery period, commonly seen clinical signs were clear or red ocular discharge, red discharge around the nose and mouth, brown nasal discharge, stained or wet perineum, and compound-stained faces.

Rats exposed to both materials showed slight to severe weight loss* on the day after exposure, followed by normal weight-gains (usually > 5 to 10 grams gained per day) throughout the remainder of the test

Testing period B:

Immediately following exposure, rats from the 93% DCH group had compound-stained faces, red nasal and ocular discharges, and some showed small red sores on the nose and ears and slight transient tremors**.

During the recovery period common clinical signs observed in rats from both exposure groups were: sores on the face, ears, and front feet; dry red nasal and ocular discharges, dry brown discharge around the mouth, partially closed eyes, yellow or brown stained perineum, compound-stained or discoloured (red) fur, hair loss on the face, labored breathing, lung noise, gasping, and lethargy. Some of these clinical signs were observed throughout the recovery period in some rats, but generally speaking the frequency and severity of the clinical signs decreased through the recovery period.

Rats exposed to 93% DCH showed moderate to severe weight loss after exposure but resumed a normal weight-gain rate by the third day after exposure. All rats exposed to 98% DCH had severe weight loss after exposure but rats which ultimately survived resumed a normal weight-gain rate by the fourth day after exposure, with some transient episodes of weight loss. One rat was found dead on the fourth day after exposure.

* Weight loss classes are defined as: Slight - < 10 grams, Moderate - 10 to 20 grams; Severe - > 20 grams.

** The slight transient tremors observed briefly in 3 of 6 rats after a single experiment were fleeting and considered not directly compound related and may have been due to physical restraint or environmental factors concurrent with the effects of near-lethal exposure to DCH.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

As no LC50 value could be extrapolated based on the experimental conditions and results.

Conclusions:

Five groups of either 10 or 6 male Crl:CD*BR rats were exposed, nose-only, to atmospheres of test material with different purities for a single, four-hour period. Mixed aerosol/vapour test atmospheres were generated by vaporising the liquid and were characterised by gas chromatography and particle size analysis. Mean total DCH concentration ranged from 3.09 to 4.73 mg/L in the 5 separate experiments. After exposure, rats were weighed and observed for clinical signs of toxicity during a 14-day recovery period. Under the conditions of this test, no 4-hour median lethal dose could be determined. A LClo was found to be 3.2 mg/l using 98% pure DCH as test material.

Executive summary:

Male rats were subjected to test acute toxicity after inhalation exposure. Of five exposures conducted with DCH formulations at concentrations greater then 3 mg/L, only one exposure produced lethality in rats. In this exposure a 98% formulation was tested using a J-tube to generate the test atmosphere. Although other exposures produced atmospheres containing higher DCH concentrations (combined aerosol/vapour), the lethal exposure atmosphere generated by the J-tube contained more vapour and less aerosol than the other experiments. In experiments using a heated round-bottom flask to evaporate the DCH, no rats died and similar results were obtained whether the DCH was evaporated under flowing air or nitrogen.

Under the conditions of this test, the 4-hour LC50 could not be determined, however the approximate lethal concentration of 98% DCH was determined to be 3.2 mg/L. No deaths occurred in any of the exposures using either the 89% or the 93% DCH formulations. This material is considered to be low to moderate in toxicity on an acute Inhalation basis in rats.