1,3-diethyl-2,4-diisocyanato-5-methylbenzene

Endpoint summary

Description of key information

In a study performed, according to OECD TG 423, no deaths were observed up to the cut-off dose of 2000 mg/kg bw. According to EU Directive 67 /548/EEC and EC Regulation 1272/2008 the test item is unclassified. 

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013-05-14 - 2013-10-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Version / remarks:

OECD- Guideline for Testing of Chemicals No. 423 -"Acute Oral Toxicity- Acute Toxic Class Method"; adopted: 17th December 2001

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Version / remarks:

EEC Directive 440/2008 Part B- Method B.1.tris, test methods pursuant to Regulation (EC) No 1907/2006 (REACH), EU Directive 67/548/EEC and EC Regulation 1272/2008.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, light protection

Confirmation of the identity of the test item was performed.

Species:

rat

Strain:

Wistar

Remarks:

RCCHan:WIST

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan GmbH, 5960 AD Horst, Netherlands
- Females (if applicable) nulliparous and non-pregnant: yes; At start of the study the animals were nulliparous and non-pregnant and free of all clinical symptoms or diseases.
- Age at study initiation: approx. 8- 12 weeks
- Weight at study initiation: 159 g- 178 g
- Fasting period before study: Yes. For administration, food was withheld from the animals for approximately 16- 24 h before administration of the test item, and they were fed again approximately 2 - 4 h after administration.
- Housing: The animals were group caged conventionally in polycarbonate cages on low dust wood granulate bedding ("SsniffBF 1, Brandenburg Holzfaserstoffe GmbH & Co. KG, Germany"). The cages of the animals were placed on racks. The wood granulate was randomly checked for contaminants at regular intervals. The analyses yielded no evidence of any adverse effects on the aim of the study. Wooden blocks for environmental enrichment were added to each cage. As soon as necessary, they were replaced by new ones. The cages were changed at least once a week. Feed racks and water bottles were not changed. All cage material was washed with hot water. In the first stage of the washing programs an alkaline cleaning agent (Neodisher Alka 300; Chemische Fabrik Dr. Weigert GmbH & Co. KG, concentration: 2.2 g/l) was used.
- Diet (e.g. ad libitum): The animals received the standard diet "ssniffR/M-H 10 mm (Ratten-/Mäuse Haltungsf.) V1534-0, ssniff Spezialdiaten GmbH, 59494 Soest", ad libitum.
- Water (e.g. ad libitum): Tap water ad libitum from polycarbonate bottles.
- Acclimation period: The acclimatization time in the animal room was at least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2°C
- Humidity (%): 55±5%
- Air changes (per hr): approx. 10 changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours rhythm.
Occasional deviations from these standards occurred, e.g. during cleaning of the animal room. They did not have any apparent influence on the outcome of the study. The animal room was provided with sound from a radio program.

Route of administration:

oral: gavage

Vehicle:

corn oil

Remarks:

dried with molecular sieve

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/ml
- Amount of vehicle (if gavage): 10 ml/kg bw

MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg bw

DOSAGE PREPARATION (if unusual):
For oral administration (gavage), Diethyltolyldiisocyanat was formulated in com oil (dried with molecular sieve). The applied formulations were well mixed before administration. The formulations for administration were prepared at room temperature.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: The starting dose level should be that which is most likely to produce mortality in some of the dosed animals.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3 + 3 females (one died due to a dosing accident in the second group).

Control animals:

no

Remarks:

not required

Details on study design:

- Duration of observation period following administration: at least 14 days
- Frequency of observations and weighing: Clinical signs and mortality rates were determined several times on the day of application and subsequently at least once daily for an observation period of at least 14 days. The weight gain of the animals was checked weekly until the end of the study.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

The LD50 value was estimated according to OECD- Guideline for Testing of Chemicals No. 423 -"Acute Oral Toxicity- Acute Toxic Class Method"; adopted: December 17, 2001.

Preliminary study:

none of the first 3 animals died

Key result

Sex:

female

Dose descriptor:

LD50 cut-off

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

not determinable due to absence of adverse toxic effects

Remarks:

none of the six animals died substance-relatedly; only death was due to gavage error

Mortality:

none of the six animals died substance-relatedly; only death was due to gavage error

Clinical signs:

other: The following clinical sign was observed: piloerection. One animal died due to a dosing accident and is not taken into account for this study. The clinical signs of this animal were: piloerection, aggravates breathing difficulties and breathing sounds

Gross pathology:

The necropsies performed at the end of the study revealed no particular findings. One animal died due to a dosing accident. The necropsy in this animal showed the following change: bloody lung.

Interpretation of results:

GHS criteria not met

Remarks:

EU implementation

Conclusions:

The study was performed scientifically reasonably according to OECD TG 423 under GLP and is well documented. Hence, the results can be considered as sufficiently reliable to assess the acute oral toxicity of the test item in rats. None of the 6 animals died related to the substance given at a dose of 2000 mg/kg bw. According to OECD guideline 423 the LD50 cut-off of Diethyltolyldiisocyanat is > 2000 mg/kg bw. According to EU Directive 67 /548/EEC and EC Regulation 1272/2008 the test item is unclassified. So it is regarded as non-toxic after oral application.

Executive summary:

This study was performed to assess the acute oral toxicity of Diethyltolyldiisocyanat to female Wistar rats according to OECD TG 423 under GLP. The test item was formulated in com oil (dried with molecular sieve); the administration volume was 10 mL/kg body weight. The results are summarized in the table below.

 

Table Dose-Response in female Wistar rats

Dosing / mg/kg	Toxicological result*	Occurrence of signs	Time of death	Mortality (%)
1st 2000	0 / 0 / 3	---	---	0
2nd 2000	0 / 2/ 2	1h – 4h	---	0

* number of animals which died spontaneously and/or were sacrificed in moribund stateInumber of animals with signs of toxicityItotal number of animals used per group

 

According to OECD guideline 423 the LD50 cut-off of Diethyltolyldiisocyanat is > 2000 mg/kg bw. According to EU Directive 67 /548/EEC and EC Regulation 1272/2008 the test item is unclassified. So it is regarded as non-toxic after oral application.

A dose of 2000 mg/kg body weight was tolerated by female rats without mortalities, effects on weight gain and gross pathological findings.

The only clinical sign was piloerection.

One animal died due to a dosing accident and is not taken into account for this study. The clinical signs of this animal were: piloerection, aggravates breathing difficulties and breathing sounds.

The necropsy in this animal showed the following change: bloody lung.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw