3-aminophenol

Endpoint summary

Description of key information

Acute oral toxicity: 

 

The acute oral toxicity dose (LD50) was considered based on different studies conducted on rats for the test chemical. The LD50 value is between 300-2000 mg/kg bw, for acute oral toxicity. Thus, comparing this value with the criteria of CLP regulation, the given test chemical can be classified for acute oral toxicity class IV.

 

Acute Inhalation Toxicity:

 

The acute Inhalation toxicity (LC50) was considered based on different studies conducted on rats for the test chemical. The LC50 value is <5 mg/L, for acute inhalation toxicity. Thus, comparing this value with the criteria of CLP regulation, the given test chemical can be classified for acute Inhalation toxicity class IV. 

 

Acute Dermal toxicity:

 

The acute dermal toxicity dose (LD50) was considered based on different studies conducted on rats and rabbits for the test chemical. The studies concluded that LD50 value is >2000 mg/kg bw, for acute dermal toxicity. Thus, comparing this value with the criteria of CLP regulation, the given test chemical cannot be classified for acute dermal toxicity.

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:

guideline study

Justification for type of information:

Data is from study report

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

Acute oral toxicity of test chemical in rats

GLP compliance:

no

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Institute for Industrial Research & Toxicology
- Age at study initiation: 7 to 9 weeks
- Weight at study initiation: 200±20g
- Fasting period before study: Fasted overnight prior to treatment. Food was offered three hours after dosing
- Housing: Groups of three animals of similar sex in polypropylene cages with stainless steel grill top, facilities for food and water bottle, and bedding of clean paddy husk
- Diet (e.g. ad libitum): Pelleted feed supplied by Pranav agro Industries Ltd., B7/6 Ramesh Nagar, Delhi, India
- Water (e.g. ad libitum): Aqua Guard filter water was kept in PVC bottles, ad libitum
- Acclimation period: One week in experimental room after veterinary examination

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22-25° C
- Humidity (%): 40-60%
- Air changes (per hr): 10-15 air changes per hour
- Photoperiod (hrs dark / hrs light): illumination cycle set to 12 hours artificial fluorescent light and 12 hours dark.

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

Dose preparation of the test article was done freshly, few minutes prior to dosing. Test substance was dissolved in distilled water to obtain final concentration of 200mg/ml.

Doses:

Group I: Dist. water, 10ml/kg body wt.
Group II: 2000 mg/kg body wt.
Group III: 2000 mg/kg body wt
The test compound was administered by oral route by using of oral cannula at the dose volume of 10 ml/kg b.wt.

No. of animals per sex per dose:

Three + one vehicle control

Control animals:

yes

Details on study design:

Body weight:
The body weight of all the animals was observed weekly on day 0 (pre treatment), 7th and 14th (post treatment).
Mortality:
The test compound was administered at different dose level in wistar albino rats observed for mortality at the time interval of 30 minutes, 1hr, 2hr, 4 hr, and 6hr time interval on the day of test compound administration and thereafter twice a day for 14 days.
Clinical Signs
The treated animals were closely observed for clinical signs of intoxication, first 4 hours and every 1 hrs interval for 24 hrs after dosing and thereafter twice a day for 14 days. All the rats were observed at least twice daily to observe any clinical signs or behavioral changes. These observations included changes in skin and fur, in the eyes and mucous membranes, respiratory, circulatory, central nervous and autonomic nervous systems, somatomotor activity and behavioral changes. The following clinical signs were observed in female mice to characterize the various systemic studies: Salivation, lacrimation, pale mucous membrane, diarrheal feaces, hunched posture, scratching, polyuria, hypoactivity etc. The clinical sign will be graded as 0 = Normal, + = Mild, ++= Moderate, +++ =High and ++++ = Severe.
Necropsy:
Necropsy was carried out on all the animals which died during the study or surviving animals were sacrificed at the end of the study to observe any gross pathological changes.

Sex:

female

Dose descriptor:

LD0

Effect level:

2 000 mg/kg bw

Based on:

test mat.

Mortality:

The test compound administered at the dose level of 2000 mg/kg b.wt did not elicit any mortality throughout the observation period of 14 days

Clinical signs:

other: Test compound did not produce any clinical signs of intoxication in wistar albino rats throughout the observation period of 14 days at the dose level of 2000 mg/kg b.wt.

Gross pathology:

NECROPSY FINDING
ABDOMINAL CAVITY
i. Opening and general examination- In the abdominal cavity all the organs were present in normal position.
ii. Spleen- Normal at 2000 mg/kg b.wt.
iii. Digestive system- No gross changes were observed.
iv. Liver and biliary ducts- No gross pathological changes were observed
v. Excretory system- No gross pathological changes were observed at the dose level of 2000 mg/kg b.wt.
vi. Adrenal- Observed normal.
vii. Male/female genital organs – Showed normal colour, consistency and no inflammatory changes.
2. THORACIC CAVITY
i. Opening and general examination- Thoracic cavity was found to be normal without any fluid, mucous or blood etc.
ii. Lungs- observed normal.
iii. Heart- No changes were observed in color and consistency. Heart found normal upto highest tested dose level 2000 mg/kg b.wt.
iv. Thyroid- Normal in shape, size and surface.
3. CRANIAL CAVITY
i. Brain- Normal in size and no gross pathological changes were observed.

Other findings:

NECROPSY FINDING
EXTERNAL
i. Skin- Skin and hair coat was observed wet.
ii. All external orifices- Normal
B. INTERNAL
i. Subcutaneous- No change was observed.
ii. Superficial and deep lymph nodes- No change in mesenteric lymph node.

Table:SUMMARY OF BODY WEIGHT (GM)

Group	Day 0	Day 7	% Gain/loss	Day 14	% Gain/loss
Group-I Distilled water 10ml/kg	203.34	209.66	2.96	213.5	5.0
Group-II 2000 mg/kg b. wt	201.25	208.19	3.44	215.21	6.93
Group-III 2000 mg/kg b. wt	202.76	207.58	2.37	216.41	6.73

TABLE :

CLINICAL SIGNS AND MORTALITY

Group: I (Vehicle Control)                                                           Dose: 10 ml/kg b.wt

FEMALE RATS

Parameters	Incidence of clinical signs observed after dosing																			Mortality
	Day 0					DAY
	Min	Hour
	30	1	2	4	6	1	2	3	4	5	6	7	8	9	10	11	12	13	14	Total^*
Mortality (total)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/3
Clinical Signs	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0            =   Normal

+            =    Mild

++           =   Moderate

+++         =    High

++++ =        Severe

TABLE :

CLINICAL SIGNS AND MORTALITY

Group: II                                                                                           Dose: 2000 mg/kg b. wt.

 

FEMALE RATS

Parameters	Incidence of clinical signs observed after dosing																			Mortality
	Day 0					DAY
	Min	Hour
	30	1	2	4	6	1	2	3	4	5	6	7	8	9	10	11	12	13	14	Total^*
Mortality (total)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/3
Clinical Signs	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0            =   Normal

+            =    Mild

++           =   Moderate

+++         =    High

++++      =   Severe

TABLE :

SUMMARY OF NECROPSY FINDINGS

 

S. No.	Fate	Wistar albino rats
		Dose (mg/kg b. wt)
		Distilled water (10 ml/kg)	2000	2000
1	Terminal sacrifice	3/3	3/3	3/3
2	Found Dead	0/3	0/3	0/3
3	Abnormalities detected	NAD	NAD	NAD

 

NAD - No abnormality recorded

Interpretation of results:

other: Not classified

Conclusions:

Based on the results obtained from present investigation, it can be concluded that the test chemical is non- toxic to wistar albino rats at the dose level of 2000 mg/kg b.wt.

Executive summary:

Acute oral toxicity study of test chemical was conducted in 3 female Wistar rats at the dose concentration of 2000mg/kg bw. Test chemical was administered through oral cannula at a dose level of 10ml/Kg bw with distill water as a vehicle. The rats were observed for 14 days for mortality and body weight changes. No mortality was observed at 2000 mg/kg bw. Hence,LD50 value was considered to be >2000 mg/kg bw, when 3 female Wistar rats were treated with test chemical by oral route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

500 mg/kg bw

Quality of whole database:

Data is Klimisch 1 and from study report

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from publication

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Acute inhalation toxicity of test chemical in rats.

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

not specified

Route of administration:

inhalation

Type of inhalation exposure:

not specified

Vehicle:

not specified

Remark on MMAD/GSD:

not specified

Details on inhalation exposure:

not specified

Analytical verification of test atmosphere concentrations:

not specified

Remarks on duration:

Exposure duration not reported

Concentrations:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

not specified

Statistics:

not specified

Preliminary study:

not specified

Sex:

not specified

Dose descriptor:

LC50

Effect level:

1 162 mg/m³ air

Based on:

test mat.

Remarks on result:

other: Other details not available

Mortality:

50% mortality observed

Clinical signs:

other: Peripheral nerve and sensation: spastic paralysis with or without sensory change Behavioural: excitement

Body weight:

not specified

Gross pathology:

not specified

Other findings:

not specified

Interpretation of results:

other: Not classified

Conclusions:

Acute inhalative toxicity value (LC50) of test chemical to rat was found to be 1162 mg/m³.

Executive summary:

The acute inhalation toxicity test was conducted on rats. Test animals were observed for body weight change and mortality.Clinical signs like Peripheral nerve and sensation: spastic paralysis with or without sensory change and Behavioural excitement was observed.

Hence, Acute inhalative toxicity value (LC50) of test chemical to rat was found to be 1162 mg/m³.This chemical has harmonised classification in the inhalation toxicity category IV.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

1 162 mg/m³ air

Quality of whole database:

Data is Klimisch 2 and from handbook.

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from publication

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

Acute dermal toxicity of test chemical in rabbits

GLP compliance:

not specified

Test type:

other: not specified

Limit test:

no

Species:

rabbit

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

not specified

Type of coverage:

other: Dermal

Vehicle:

not specified

Details on dermal exposure:

not specified

Duration of exposure:

not specified

Doses:

8112 mg/kg bw

No. of animals per sex per dose:

not specified

Control animals:

not specified

Details on study design:

not specified

Statistics:

not specified

Preliminary study:

not specified

Sex:

not specified

Dose descriptor:

LD50

Effect level:

8 112 mg/kg bw

Based on:

test mat.

Mortality:

50% mortality was observed at 8112 mg/kg bw

Clinical signs:

other: not specified

Gross pathology:

not specified

Other findings:

not specified

Interpretation of results:

other: Not classified

Conclusions:

The acute dermal LD50 value was considered to be 8112 mg/kg bw, when rabbits were treated with test chemical by dermal application.

Executive summary:

Acute dermal toxicity study of test chemical was conducted inrabbits at the dose concentration of 8112mg/kg bw. 50% mortality was observed at 8112 mg/kg bw. Hence,LD50 value was considered to be 8112 mg/kg bw, when rabbits were treated with test chemical by dermal application.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

8 112 mg/kg bw

Quality of whole database:

Data is Klimisch 2 and from authoritative database

Additional information

Acute oral toxicity:In different experimental studies, test chemical has been investigated for acute oral toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rats and mice for test chemical. The studies are summarized as below –

The GLP-compliant study was performed according to OECD Guideline 420 Acute Oral Toxicity: Fixed Dose Procedure. The study assessed the potential acute toxicity of the test substance to female Sprague-Dawley rats. The test item was administered by oral route (gavage) at the dose-level of 500 mg/kg, to one group of five fasted Sprague-Dawley female rats, including that of the sighting test. A preliminary test (sighting test) preceded the definitive test (main experiment). The test item was prepared in a 0.5% suspension of methylcellulose and administered to the animals under a volume of 10 mL/kg. Clinical signs and mortality were checked for a period of 14 days following the single administration of the test item. The animals were checked for body weight gain and were subjected to necropsy. In Sighting test, no clinical signs and no mortality were observed at the 500 mg/kg dose-level in one tested animal. At the 2000 mg/kg dose level, the treated animal was found dead on day 2; sedation and tonic-clonic convulsions were observed prior to death. In main experiment, at the 500 mg/kg dose-level, no mortality occurred. Hypoactivity or sedation, piloerection, and dyspnea were observed in all animals on day 1. Recovery was complete on day 2. The body weight gain of the animals given 500 mg/kg was not affected by treatment with the test item. At necropsy, no apparent abnormalities were observed. Under the experimental conditions, maximal non-lethal dose of the test item m-Aminophenol (batch No. 220117) is higher than 500 mg/kg. According to CLP classification, the LD50 could be estimated between 500 and 2000 mg/kg bw. The registered item was defined as acute oral hazard category 4.

The above GLP study is supported by another experimental study conducted in swiss mice for the test chemical to determine the acute test method. Albino mice were orally treated with test chemical diluted in water at pH3 en suspended in methocel at 0.5%. Croissant doses were sued in order to obtain a LD50 (lethal dose 50) value. Survivals were kept in observation for 14 days after treatment. Mortality occurred at all dose groups except the 180 mg/kg group. There were 1, 2, 5, 7, 8, 10 premature deaths respectively in 200, 250, 300, 400, 500 and 631 mg/kg dose groups. According the information of this study, the LD50 value was calculated at 330 mg/kg for mice. However, there was insufficient detail on method and results for assessment.

Both the above experimental studies are contradicted with the study conducted as per OECD No. 423 (acute toxic class method) to evaluate acute oral toxicity dose for test chemical in 3 females/step Wistar rats at the dose concentration of 2000 mg/kg bw. In Step-I, the test compound was dissolved in distilled water and administered orally at the dose level of 2000 mg/kg body weight (dose volume 10ml/kg) to 3 female rats. However; vehicle control group treated with the distilled water at the dose level of 10 ml/kg b.wt. The treated animals were closely observed for clinical signs of intoxication during first 4 hours of test compound administration. Thereafter, all the animals were observed periodically at one hour interval for 24 hrs and once daily for a period of 14 days. The necropsy was performed on all animals which died during the study or were sacrificed at termination of the study. The rats treated with the test compound did not show any mortality as well as clinical signs of toxicity throughout the observation period. No clinical signs and mortality were observed in vehicle control group.The necropsy finding did not reveal any gross pathological changes in any of the animal with the exception of mild congestion in lungs in one animal. In Step-II, after 72 hrs, the result of step-I was confirmed by administration of same dose level (2000 mg/kg. b.wt) of test compound in additional 3 animals of same sex (OECD-423 guidelines). The test compound was mixed with distilled water and administered orally at the dose level of 2000 mg/kg body wt. (dose volume 10 ml/kg) to 3 female rats. All the animals were closely observed for clinical sign of toxicity and mortality gross pathological changes individually once in 30 minutes, 1, 2, 4 and 6 hrs intervals during the first 24 hrs and thereafter, once daily for a period of 14 days. All the animals were died during the experimentation examined for gross pathological changes. The test compound administered at the dose level of 2000 mg/kg b.wt did not produce any mortality throughout the observation period of 14 days. Furthermore, no clinical signs of toxicity were recorded throughout the period of observation. The necropsy finding did not show any gross pathological changes related to compound toxicity. Therefore, it is concluded that the test compound following the guideline OECD-423 is non- toxic to wistar albino rats at the dose level of 2000 mg/kg b.wt. Though the LD50 dose determined to be >2000 mg/kg bw, the given study is not conducted as per GLP criteria.

Another experimental study mentioned in publications, handbooks and secondary source, for the target chemical was conducted in groups of 10 male and female CFY rats at the dose concentration of 1000 (500-1800) mg/kg bw. The test chemical was suspended in 0.5% aqueous gum tragacanth, containing 0.05% Na2SO3 and administered as 10% via oral gavage route. Rats treated with the vehicle alone served as controls. In a preliminary range finding study, the freshly prepared solutions or suspensions were administered to groups of two male and two female rats by oral intubation in a range of dosage volumes, in order to find the approximate median lethal oral dose (LD50). After these preliminary range-finding tests had given a rough approximation of the LD50, larger groups of rats (five males and five females) were used in order to locate the median lethal dose more precisely. A logarithmic dosage interval of 1.6 was used for test material. During the observation period of 14 days, a record was kept of all deaths and signs of toxicity. All rats that died were examined macroscopically in an attempt to identify the target organs, and animals surviving to the end of the experiment were similarly examined at that time to detect any possible residual damage. There was no microscopic examination of the various tissues and organ systems. The LD50 and its 95% confidence limits were calculated from the mortality data either by the method of Litchfield & Wilcoxon (1949) or by that of Weil (1952). 50% mortality was observed at 1000 mg/kg bw. Signs of reaction to treatment, observed shortly after dosing of the compound, included lethargy and piloerection. Other reactions elicited included increased salivation, ataxia, fine body tremors, and changes in respiratory rate, dieresis and diarrhoea. Autopsy of the animals that died as a result of treatment revealed changes which, in many cases, included darkening of the liver and kidneys, darkening or pallor of the spleen, hemorrhage of the lungs and intestines, and injection of the intestinal and mesenteric blood vessels. Autopsy of the survivors at the end of each experiment did not reveal any abnormalities indicative of residual systemic effects. Hence, LD50 value was considered to be 1000 mg/kg bw, with 95% confidence limit of 500-1800 mg/kg bw, when groups of 10 male and female CFY rats were treated with 3-Aminophenol via oral gavage route.

The above study is supported with the study mentioned in publications and secondary sources, for the target chemical. The acute oral toxicity study was conducted in groups of 2 male and 2 female rats at the dose concentration of 1660 mg/kg bw. The test chemical was suspended in 0.5% aqueous gum tragacanth, containing 0.05% Na2SO3 and administered as 10% via oral gavage route. 50% mortality was observed at 1660 mg/kg bw. Hence, LD50 value was considered to be 1660 mg/kg bw, when groups of 2 male and 2 female rats were treated with test chemical via oral gavage route.

These studies are supported with the study mentioned in authoritative databases, for the target chemical. The acute oral toxicity study was conducted according to OECD Guideline 401 in 5 male and 5 female per group of Sprague-Dawley (Crj: CD (SD) IGS) rats at the dose concentration of 500, 700, 1000, 1400 and 2000 mg/kg bw. The given test chemical was dissolved in 1% aqueous solution of carmellose and administered as 5 mL/kg via oral gavage route. General condition was frequently observed until 6 hours after administration, and thereafter once a day until the day of necropsy at 14 days after administration. Body weight measurement was made before administration on the administration day, 1, 3, 5, 7, 10 and 14 days after administration. Necropsy of survivors was performed. The death cases were found promptly after the discovery, surviving cases were observed on the external table on the 14th day after administration, and exsanguination was killed under ether anesthesia, and the organs and tissues of the whole body were observed macroscopically. For all cases of survival at necropsy, the weights of the liver, kidney and spleen were measured; the absolute weight was divided by the body weight on the day of autopsy and multiplied by 100 to calculate the relative weight. Animals were observed for Histopathology examination.LD50 value was calculated by probit method using the number of animals of male and female and the number of dead animals. Mortality was observed in 3, 5 and 5 cases in males, in 1, 4 and 5 cases in females respectively, up to 3 days after administration in the 700, 1000 and 1400 mg/kg group. In the 500 mg/kg administration group, tremor in the male and female, salivation in females, brown urine, and prone were observed in the group administered with 500 mg/kg, salivation in both males and females, brown urine, prone lying, lying in 700 mg/kg or more. The paleness of limbs and auricle was also delayed. These symptoms appeared from several minutes to 4 hours after administration, paleness of limb/auricle was seen in the group administered with 700 mg/kg or more of both sexes from 1 day after administration to 3 days after administration. Besides, a decrease in locomotor activity, a dark red color and trauma at the tip of the tail, an abdomen, and a breathing stimulus were also found, and death cases were also observed. Even in the case of surviving until 14 days after administration, the paleness of the limb/auricle, the dark purple color and missing of the tip of the tail were observed. There was no significant difference in the amount and weight gain rate. Thinning of glandular gastric mucosa was observed in males in deceased cases, dark red or dark brown spots of the glandular gastric mucosa or swelling of the spleen were observed in both males and females, dark reddening and trauma of the tip of the tail and Pleural effusion and dark reddening of the adrenal glands were observed. In surviving cases, testis, epididymis and seminal vesicle were small in one case of males' group receiving 700 mg/kg. Spleen dark reddening, dark browning of the kidneys, dark purple coloration and missing of the tip of the tail were observed in female 700 and 1000 mg/kg administration group. Organ weight -The relative weight of liver and spleen showed a high tendency in male 700 mg/kg administration group. In the female group receiving 700 mg/kg, the absolute weight of the spleen showed a high value, and the relative weight tended to be high. In the 700 and 1000 mg/kg administration group, the relative weight of the liver tended to be high. In one group of 1000 mg/kg administration group, the relative weight of the spleen tended to be high. Histopathology examination -In the dead, mild congestion was seen in the spleen in the sexes of 700 and 1000 in male and male and 1400 mg/kg in males, and in male 700 and 1000 mg / kg administration group, mild to moderate localized or extensive Necrosis was seen. Mild hemosiderin-like brown pigment deposition was also observed in Kupffer cells of the liver and proximal renal tubular epithelium of the kidney. In male and female 700 mg/kg administration group, mild eosinophilic cytoplasmic inclusion body showing PAS staining positive in kidney proximal renal tubular epithelium was found. In the surviving cases, mild hemosiderin-like brown pigment deposition was observed in liver Kupffer cells and kidney proximal renal tubular epithelium in female 700 and 1000 mg/kg administration group. Male hemosiderin-like brown pigment was also observed in the spleen in female 500, 700 and 1000 mg/kg administration group. On the other hand, no change was seen in males. Hence, LD50 value was considered to be 693 mg/kg for males and 856 (667-1139) mg/kg for females, when 5 male and 5 female per group Sprague-Dawley (Crj: CD (SD) IGS) rats were treated with test chemical via oral gavage route.

The above study is supported with the study conducted in rats and mentioned in authoritative database, publication and secondary source, for the target chemical. Acute oral toxicity study was conducted according to OECD 420 "fixed dose method" in 4 females Sprague-Dawley rats at the dose concentration of 500 mg/kg bw. The given test substance (Batch: 20117, Purity: 99%) suspended in 0.5 % methylcellulose and administered via oral gavage route. Clinical signs and mortality were checked for 2 weeks. Animals were observed for body weight changes. Necropsy of survivors performed. No mortality was observed at 500 mg/kg bw. On day 1 hypoactivity or sedation, pilorection and dyspnea were observed in all animals. Recovery was complete on day 2. Body weight gain was normal. Macroscopic examination revealed no abnormalities. Hence, LD50 value was considered to be >500 mg/kg bw, when 4 females Sprague-Dawley rats were treated with test chemical via oral gavage route.

This study is further supported with the study mentioned in publication and secondary source, for the target chemical. The study was conducted in rats at the dose concentration of 812 mg/kg bw. 50% mortality was observed at 812 mg/kg bw. Hence, LD50 value was considered to be 812 mg/kg bw, when rats were treated with 3-Aminophenol via oral route.

Another experimental study mentioned in handbook and authoritative databases, for the target chemical was conducted in rats at the dose concentration of 924mg/kg bw. Animals were observed for mortality, clinical signs and behavioural changes. 50% mortality was observed at 924 mg/kg bw. Clinical signs were observed such as, changes in respiration rate and behavioural changes like excitement. Changes in peripheral nerve and sensational changes; spastic paralysis with or without sensory changes were observed. Hence, LD50 value was considered to be 924 mg/kg bw, when rats were treated with test chemical via oral route.

This study is supported with the study mentioned in handbook for the target chemical was conducted in mice at the dose concentration of 420 mg/kg bw. Animals were observed for mortality, clinical signs and behavioural changes. Necropsy of survivors performed. Mortality was observed at 420 mg/kg bw within days. The toxic symptoms include excitation, mucosal irritation, convulsions and paralysis. Gross pathology examination revealed hemodynamic disorders in the visceral organs. Neither Heinz bodies, nor methemoglobinemia were found. Hence, LD50 value was considered to be 420 mg/kg bw, when mice were treated with test chemical via oral route.

Above study is also supported with the study conducted on mice and mentioned in handbook and authoritative databases, for the target chemical. Animals were observed for mortality, clinical signs and behavioural changes. 50% mortality was observed at 401 mg/kg bw. Clinical signs were observed such as, changes in respiration rate and behavioural changes like excitement. Changes in peripheral nerve and sensational changes; spastic paralysis with or without sensory changes were observed. Hence, LD50 value was considered to be 401 mg/kg bw, when mice were treated with test chemical via oral route

All the above experimental studies are further supported with the study mentioned in secondary sources, for the target chemical. The study was conducted in mice at the dose concentration of 330 mg/kg bw. 50% mortality was observed at 330 mg/kg bw. Hence, LD50 value was considered to be 330 mg/kg bw, when mice were treated with test chemical via oral route.

Thus, based on the above experimental studies on test chemical, maximum studies concluded that the LD50 value is between 300-2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, test chemical can be classified as “Category 4” for acute oral toxicity.

Acute Inhalation Toxicity:

In following study, test chemical has been investigated for acute inhalation toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rats for test chemical along with the study available for structurally and functionally similar read across substance. The studies are summarized as below –

The experimental study mentioned in handbook and authoritative databases for the target chemical was conducted in rats at the dose concentration of 1162 mg/m3. Animals were observed for mortality, clinical signs and behavioural changes. 50% mortality was observed at 1162 mg/m3. The animals suffered from spastic paralyses, agitation and respiratory disorders. Hence, LC50 value was considered to be 1162 mg/m3, when rats were treated with test chemical via inhalation route by aerosol for 2 hour exposure.

2. Acute inhalation toxicity study of test chemical was conducted according to OECD Guide-line 403 "Acute Inhalation Toxicity" in groups of 5 male and 5 female Wistar rats at the dose concentration of 0, 0.9, 1.94, 2.5, 5.06 mg/L (0, 900, 1940, 2500, 5060, mg/m3). The rats were exposed (head-nose) to the 50% aerosol of given test chemical (purity: 99.9%) in polyethylene glycol 400/ethanol (1:1).Animals were observed for mortality, clinical signs and body weight changes for 14 days. Necropsy of survivors performed. All deaths occurred within 2 days after exposure. Clinical signs were observed such as, irregular breathing, impaired motility, impaired reflexes, blood-stained secretion from nose, encrusted noses, corneal opacities, diarrhea, and reduced activity were seen at higher concentrations (the exposure levels at which these signs occurred were not stated). In the surviving animals, all clinical signs were fully reversible within 12 days. Reduced body weight gain was noted during the first week after exposure, but was normal at the end of the second week. At necropsy, the animals that had died during the experiment had discolored and mottled lungs which were foamy and filled with liquid. Animals that survived to the end of the study showed no pathological changes. Hence, LC50 value was considered to be 2200 mg/m3, when groups of 5 male and 5 female Wistar rats were treated with test chemical via inhalation route by aerosol (head-nose) for 4 hour exposure.

3. Acute inhalation toxicity study of the given test chemical was conducted in 70 male and female Sprague Dawley rats at the dose concentrations of 0.01, 0.026, 0.30, 1.13, 1.48, 1.38, and 1.42 mg/L via inhalation route by concentrated vapors/aerosols for 4 hours exposure. The average particle size (mass median diameter) ranged from 3.8 to 5.8 µm (standard deviation of 2.5 to 6.0). The animals were observed for mortality, clinical signs and body weight changes daily after exposure. Necropsy of survivors performed. 50% mortality was observed in animals between 1.13 - 1.48 mg/l. Daily observations indicated that body weight loss, nasal discharge, decreased activity, and possible slight respiratory difficulty occurred subsequent to exposure. No lesions were noted during post mortem examination. Therefore, the LC50 value was considered in between 1.13 - 1.48 mg/l, when 70 male and female Sprague Dawley rats were treated with the given test chemical via inhalation route by concentrated vapors/aerosols for 4-hours exposure.

Thus, based on the above study on test chemical and it’s structurally and functionally similar read across substance, it can be concluded that LC50 value is between 1.0-5.0 mg/L. Thus, comparing this value with the criteria of CLP regulation, test chemical can be classified as “category 4” for acute inhalation toxicity.

Acute Dermal toxicity:

In different studies, test chemical has been investigated for acute dermal toxicity to a greater or lesser extent. Often are the studies based on in-vivo experiments in rodents, i.e. most commonly in rabbits for test chemical along with the studies available for structurally and functionally similar read across substances. The studies are summarized as below –

The experimental study mentioned in authoritative database for the target chemical was conducted in rabbits at the dose concentration of 8112mg/kg bw. 50% mortality was observed at 8112 mg/kg bw. Hence, LD50 value was considered to be 8112 mg/kg bw, when rabbits were treated with test chemical by dermal application.

The above study is supported with study mentioned in authoritative database for the test chemical. The acute dermal toxicity study was conducted in rabbits at the dose concentration of 10000 mg/kg bw. No mortality was observed at 10000 mg/kg bw. Hence, LD50 value was considered to be >10000 mg/kg bw, when rabbits were treated with test chemical by dermal application.

Both the above studies are further supported with the study mentioned in publication and authoritative database for the test chemical. The acute dermal toxicity study was conducted in 6 male and 6 female New Zealand white rabbits at the dose concentration of 5000mg/kg bw. The back of each rabbit was clipped free of hair and the animals were fitted with plastic collars to prevent oral ingestion of the compound. The test chemical was applied to the back of each rabbit with a gauze pad. The pads were left in place under semiocclusive conditions for 24 hr. The rabbits were observed for 7 days after patch removal. No mortality was observed at 5000 mg/kg bw. Hence, LD50 value was considered to be >5000 mg/kg bw, when 6 male and 6 female New Zealand white rabbits were treated with test chemical by dermal application semiocclusively for 24 hour.

Thus, based on the above study on test chemical and it’s structurally and functionally similar read across substances, it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, test chemical cannot be classified for acute dermal toxicity.

Justification for classification or non-classification

Based on the above experimental studies on test chemical and it’s structurally and functionally similar read across substances, it can be concluded that LD50 value is between 300-2000 mg/kg bw for acute oral toxicity; LD50 value is >2000 mg/kg bw for acute dermal toxicity; and LC50 value is between 1.0-5.0 mg/L for acute inhalation toxicity. Thus, comparing these values with the criteria of CLP regulation, test chemical can be classified as “Category 4” for acute oral and inhalation toxicity and cannot be classified for acute dermal toxicity.