2-[4-[(2-chloro-4-nitrophenyl)azo]-N-(2-cyanoethyl)anilino]ethyl acetate

Endpoint summary

Description of key information

Oral LD50 (male and female) > 5350 mg/kg bw

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: animals were purchased from KFM, CH-4414 Fülllinsdorf, Switzerland.
- Age at study initiation: young adult, age not specified.
- Weight at study initiation: ranged between 140 and 180 g.
- Fasting period before study: access of food only was prevented approximately 18 hours prior and 4 hours after the dosing. The water bottles were withdrawn 2 hours prior and 4 hours after dosing.
- Housing: housed individually in Macroron cages.
- Diet: standard laboratory pelleted diet (KLIBA no. 24-343-7 from Klingentatmühle AG, Basle). The batch of diet used for the study was analysed for chernical and microbiological contaminants.
- Water: ad libitum.
- Acclimation period: animals were acclimatised to the experimental environment for a period of about five days prior to the start of the study.

ENVIRONMENTAL CONDITIONS
- Temperature: 23 ± 2 °C
- Humidity: 50 ± 10 %
- Air changes: approximately 15 changes/hour.
- Photoperiod: the light/dark cycle was 12 hours.

Route of administration:

oral: gavage

Vehicle:

DMSO

Details on oral exposure:

- Test fomulation: test item was dissolved in DMSO; the test sample was prepared immediately before dosing.
- Dose volume: 15 mI per kg body weight.

Doses:

5350 mg/kg bw, higher dosages were not applicable.

No. of animals per sex per dose:

5 male and 5 female.

Details on study design:

- Duration of observation period following administration: the animals, on both the preliminary and the main studies, were observed for 14 days after dosing.
- Frequency of observations: animals were observed soon after dosing, then at hourly intervals for the remainder day 1. On the subsequent days the animals were observed once in the morning and once in the late afternoon. Clinical signs were recorded at each observation.
- Frequency of weighing: individual body weights were recorded on day 1, 7 and 14.
- Necropsy of survivors performed: surviving animals were killed after two weeks. All animals which died during the study and those killed after two weeks were subjected to a macroscopic postmortem examination. The macroscopic appearance of the abnormal organs was recorded.

PRELIMINARY TEST
A preliminary study was carried out to establish a dosing regimen, using groups of two males and two females at two dosage, using 10-15 ml/kg body weight.

Statistics:

The acute oral LD50 was determined using the probit method of L.C. Miller and M.L. Tainter (Proc. Soc. exper. Biol. Med. 57 (1944) p. 26) or calculated by computer using the method of D.J. Finney (3rd. ed., 1971). The given doses always referred to the test material.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 350 mg/kg bw

Based on:

test mat.

Remarks on result:

not determinable due to absence of adverse toxic effects

Mortality:

No death occurred during the range-finding experiment.
During the main experiment, one female died 59 hours after dosing.

Clinical signs:

No overt symptoms of poisoning were observed.

Gross pathology:

No special findings could be detected.

Mortality ratio and group mean bodyweight (g) of rats

Sex	Dosage	Bodyweight (g) at			Mortality ratio
		Dosing	1 wk	2wks
Male	Test item, 5350 mg/kg bw	177	207	246	0/5
Female	Test item, 5350 mg/kg bw	166	163	183	1/5

Interpretation of results:

other: not classified, according to CLP Regulation (EC 1272/2008)

Conclusions:

LD50 > 5350 mg/kg bw (males and females)

Executive summary:

Test item was dissolved in DMSO; the test sample was prepared immediately before dosing. A preliminary study was carried out to establish a dosing regimen, using groups of two males and two females at two dosage, using 10-15 ml/kg body weight. In the main experiment, groups of five male and five female rats were dosed at levels selected using the results of the preliminary study. The animals were dosed by oral gavage by means of a stomach tube and the dosed volume was 15 ml per kg body weight. The animals on both, the preliminary and the main studies were observed for 14 days after dosing.

Surviving animals were killed after two weeks. All animals which died during the study and those killed after two weeks were subjected to a macroscopic postmortem examination. The macroscopic appearance of the abnormal organs was recorded.

One female died 59 hours after dosing. No overt symptoms of poisoning were observed. No special findings could be detected.

Conclusion

LD50 > 5350 mg/kg bw (males and females)

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 350 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

ACUTE ORAL TOXICITY

A study was performed to assess the acute oral toxicity of the test material in the young adult male and female Han-wistar strain rat. Test item was dissolved in DMSO. A preliminary study was carried out to establish a dosing regimen, using groups of two males and two females at two dosage, using 10-15 ml/kg body weight. In the main experiment, the animals were dosed with 5350 mg/kg bw, by oral gavage. One female died 59 hours after dosing; no overt symptoms of poisoning were observed and no special findings could be detected.

A second experiment conducted on Direct Red 054 is available; however, it was performed using a sample with a limited content of test item, thus, it is here reported just as a supporting study.

The test item was suspended in 40 % aqueous gun tragacanth (0.5 %) and given to a group of five male and five female rats; in addition, five males and five females were treated with vehicle only and served as control. The animals were dosed at 5000 mg/kg bw by oral intubation.

One female rat died within 43 hours of treatment; the autopsy did not reveal any specific cause of death. Signs of reaction to treatment, observed shortly after treatment consisted of lethargy, piloerection and moderate diuresis. The urine and fur of all rats was stained red. Recovery of survivors, as judged by external appearance and behaviour, was apparently complete within four days of treatment. Slightly depressed bodyweight gains were observed in female rats during the first week of the observation period, but returned to normal during the second week of observation, compared with controls. Terminal autopsy findings were normal in all rats.

ACUTE INHALATION TOXICITY

No acute toxicity studies by inhalation route are available on Disperse Red 054. Nevertheless, because of the physical state of the substance inhalation is not an appropriate route of exposure. The vapour pressure of the substance is estimated to be negligible; the particle size distribution showed that the 98.2 % of particles have a diameter higher than 45 µm; thus, Disperse Red 054 is characterized by particles not-respirable. This consideration, together with the consideration that the substance is manufactured and handled with suitable risk management measures and with the suitable personal protective equipments, lets to consider the possible absorption of the substance by inhalation route as negligible.

ACUTE DERMAL TOXICITY

No acute toxicity studies by dermal route are available on Disperse Red 054. Nevertheless, the possible absorption rate of the substance by dermal route is not expected to be significant.

In the Commission Regulation (EU) 2016/863, amending Annexes VII and VIII to REACH Regulation (EC 1907/2006), it is explained that recent scientific analysis of available data from in vivo acute toxicity studies have shown that substances that are not toxic via the oral route may be expected with high certainty to be also non-toxic via the dermal route. Therefore, testing those substances via the dermal route does not provide essential information for their safety assessment. The amendment is the consequence of studies and scientific debates. In particular, the 15^th Meeting of Competent Authorities for REACH and CLP (CARACAL, 2014) concluded that the avoidance of a dermal route test is justified for substances that have shown no toxicity in acute oral toxicity test up to the limit dose of 2000 mg/kg bw.

Since during the oral acute toxicity tests no signs of systemic toxicity were recorded, the substance is not expected to be harmful/toxic by dermal route.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.1 Acute toxicity section, substances can be allocated to one of four toxicity categories based on acute toxicity by the oral, dermal or inhalation route according to the numeric criteria. Acute toxicity values are expressed as (approximate) LD50 (oral, dermal) or LC50 (inhalation) values or as acute toxicity estimates (ATE).

The oral LD50 value was established to be greater than 5000 mg/kg bw, therefore the test substance is out of any classification limit for acute oral toxicity (oral acute toxicity category 4: 300 < ATE ≤ 2000 mg/kg bw).

In conclusion, the test substance does not meet the criteria to be classified for oral acute toxicity, according to the CLP Regulation (EC 1272/2008).