4-methyl-1-phenyl-3-pyrazolidone

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 627 mg/kg bw. The study concluded that 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 in “Category 4” for acute oral toxicity.

Acute Inhalation Toxicity:

The acute inhalation toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical, which is reported to be 0.00122 Pa. Thus, exposure to inhalable dust, mist and vapour of the chemical is highly unlikely. Therefore this study is considered for waiver.

Acute Dermal toxicity:

The acute dermal toxicity dose (LD50) was considered based on study conducted on rats for the given test chemical. The study 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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Justification for type of information:

data is from study report

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Qualifier:

equivalent or similar to guideline

Guideline:

other: Federal Register Vol 50 no 188, Part II, 27 September 1985

Version / remarks:

section 798-1175-Acute oral toxicity

Principles of method if other than guideline:

Acute Oral toxicity test was carried out to study the effects of the given test chemical on rats.

GLP compliance:

yes

Remarks:

statement by study director and statement by QA

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River UK Ltd, Margate, Kent, England
- Strain: pretest CFY, main test CD
- Age at study initiation: 4-6 weeks
- Weight at study initiation: 100-149 g
- Fasting period before study: overnight and 4 hours after dosing
- Housing: in metal cages with wire mesh floors
- Diet: Labsure LAD 1 ad libitum
- Water: ad libitum
- Acclimation period: at least 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-23 °C
- Humidity (%): average 57%
- Air changes (per hr): 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

methylcellulose

Details on oral exposure:

VEHICLE: 1% methylcellulose
MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

Doses:

pre-test: 800, 1600 and 5000 mg/kg bw
main test: 500, 800 and 1260 mg/kg bw

No. of animals per sex per dose:

pre-test: 2/sex/dose
main test: 5/sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days (pre-test 5 days)
- Frequency of observations: twice daily (and at regular intervals on day 1)
- Bodyweight: on day 1, 8 and 15
- Necropsy of survivors performed: no (only on animals that died)
- Other examinations performed: clinical signs daily

Statistics:

Probit analysis (Finney)

Preliminary study:

All animals died at 1600 and 5000 mg/kg bw on day 1
At 800 mg/kg bw 1 male died on day 1

Sex:

male/female

Dose descriptor:

LD50

Effect level:

627 mg/kg bw

Based on:

test mat.

95% CL:

>= 425 - <= 783

Sex:

male

Dose descriptor:

LD50

Effect level:

578 mg/kg bw

Based on:

test mat.

95% CL:

>= 329 - <= 787

Sex:

female

Dose descriptor:

LD50

Effect level:

685 mg/kg bw

Based on:

test mat.

95% CL:

>= 437 - <= 983

Mortality:

males: 500 mg/kg bw 2/5 before day 4; 800 mg/kg bw 5/5 before day 3; 1260 mg/kg bw 4/5 on day 1
females: 500 mg/kg bw 0/5 before day 4; 800 mg/kg bw 4/5 on day 1; 1260 mg/kg bw 5/5 on day 1

Clinical signs:

other: pilo-erection, hunched posture, waddling, decreased respiratory rate and pallor of the extremities in all animals Ptosis, prostrate and facial swelling were observed less frequently.

Gross pathology:

No abnormalities was observed.

Other findings:

not specified

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The acute oral toxicity dose (LD50) value was considered to be 627 mg/kg bw, with 95% confidence limit of 425-783 mg/kg bw in combined male and female rats; 578 mg/kg bw, with 95% confidence limit of 329-787 mg/kg bw in male rats and 685 mg/kg bw, with 95% confidence limit of 437-983 mg/kg bw in female rats.

Executive summary:

The acute oral toxicity study was conducted as per OECD Guideline 401 (Acute Oral Toxicity) and Federal Register Vol 50 no 188, Part II, 27 September 1985 by using the given test chemical in male and female Sprague-Dawley rats.

The given test chemical (Purity 100%) was dissolved in 1% methylcellulose and administered as 10 mL/kg bw via oral gavage route.

In pre-test: 2/sex/dose male and female Sprague-Dawley rats were treated with the given test chemical at the dose concentration of 800, 1600 and 5000 mg/kg bw. Animals were observed for mortality for 5 days. Necropsy was performed only on animals that died. All animals died at 1600 and 5000 mg/kg bw on day 1. At 800 mg/kg bw 1 male died on day 1.

In main test: 5/sex/dose male and female Sprague-Dawley rats were treated with the given test chemical at the dose concentration of 500, 800 and 1260 mg/kg bw.

Animals were observed for mortality daily twice (and at regular intervals on day 1). Body weight was observed on day 1, 8 and 15. Necropsy of survivors performed only on animals that died. Clinical signs were observed daily. LD50 value was calculated by the method of probit analysis (Finney).

Mortality was observed as - males: At 500 mg/kg bw 2/5 before day 4; At 800 mg/kg bw 5/5 before day 3; At 1260 mg/kg bw 4/5 on day 1. Females: At 500 mg/kg bw 0/5 before day 4; At 800 mg/kg bw 4/5 on day 1; At 1260 mg/kg bw 5/5 on day 1. Clinical signs like, piloerection, hunched posture, waddling, decreased respiratory rate and pallor of the extremities in all animals and Ptosis, prostrate and facial swelling were observed less frequently in treated animals. Body weight change was observed for survivors within normal ranges. No abnormalities were observed after necropsy.

Under the condition of the study, the acute oral toxicity dose (LD50) value was considered to be 627 mg/kg bw, with 95% confidence limit of 425-783 mg/kg bw in combined male and female rats; 578 mg/kg bw, with 95% confidence limit of 329-787 mg/kg bw in male rats and 685 mg/kg bw, with 95% confidence limit of 437-983 mg/kg bw in female rats.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

627 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

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Quality of whole database:

Waiver

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Data is from experimental study report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Principles of method if other than guideline:

This study was designed to determine the dermal LD50 of the test item (up to 2000 mg/kg) or to establish a non-lethal dose level of 2000 milligram of test item per kilogram of body weight.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: National Institute of Biosciences, Pune.
- Age at study initiation: Young adult male and female rats aged between 8 – 12 weeks were used.
- Weight at study initiation: The weight range of approximately 212.0 to 237.6 grams at initiation of dosing.
Body weights at the start : Male Mean: 233.08 g (= 100 %); Minimum : 228.7 g (- 1.88 %); Maximum : 237.6 g (+ 1.94 %)
Female Mean : 215.88 g (= 100 %); Minimum : 212.0 g (- 1.80 %); Maximum : 220.5 g (+ 2.14 %)
- Identification: Each rat was individually identified by the cage number.
- Housing: The rats were individually housed in polycarbonate cages with paddy husk as bedding.
- Diet (e.g. ad libitum): Rodent feed supplied by the Nutrivet Life Sciences, Pune, was provided ad libitum from individual feeders.
- Water (e.g. ad libitum): Water was provided ad libitum from individual bottles attached to the cages. All water was from a local source and passed through the reverse osmosis membrane before use.
- Acclimation period: 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.6 to 22.6 degree centigrade.
- Humidity (%): 55.1% to 59.7%.
- Air changes (per hr): Ten to fifteen air changes per hour.
- Photoperiod (hrs dark / hrs light): An artificial light and dark cycle of 12 hours each was provided to the room.

IN-LIFE DATES: 09-08-2017 to 24-08-2017

Type of coverage:

occlusive

Vehicle:

water

Remarks:

(Distilled water)

Details on dermal exposure:

TEST SITE
- Area of exposure: Trunk (dorsal surface and sides from scapular to pelvic area)
- % coverage: Approximately 10% of the body surface area.
- Type of wrap if used: Porous gauze dressing and non-irritating tape.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Distilled water was used to remove residual test item.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw
- For solids, paste formed: Yes

Duration of exposure:

24 hours

Doses:

A single dose of 2000 mg of the test item per kilogram of body weight was administered to ten rats (five males and five females).

No. of animals per sex per dose:

10 (5/sex).

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Twice daily
- Necropsy of survivors performed: Yes
- Other examinations performed: Clinical Observations and General Appearance: Animals were observed for clinical signs, mortality, until sacrifice.
Onset, duration and severity of any sign were recorded. The clinical signs and mortality observations were conducted at 10, 30, 60 minutes, 2, 4 and 6 hours on the day of dosing and once daily thereafter for 14 day. Daily observation was done as far as possible at the same time.
The observations were included general clinical signs, observations of eyes, mucous membranes, respiratory, circulatory system and behavior pattern.

Evaluation of Dermal Reaction: Dermal reaction was observed daily for study period of 14 days.

Body weights: Individual animal body weights were recorded pre-test (prior to administration of the test item), day 7 and at termination on day 14.

Gross Pathology: Necropsy was performed on animals surviving at the end of the study. Macroscopic examination of all the orifices, cavities and tissues were made and the findings were recorded. All animals surviving the study period were sacrificed by the carbon dioxide asphyxiation technique (day 15).

Histopathology: No gross abnormalities were observed in animals sacrificed terminally hence, no histopathology was performed.

Statistics:

not specified

Preliminary study:

not specified

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

Sex : Male Group I - Animal treated at the dose level of 2000 mg/kg body weight: All animals survived through the study period of 14 days.
Sex : Female Group I - Animal treated at the dose level of 2000 mg/kg body weight: All animals survived through the study period of 14 days.

Clinical signs:

other: Sex : Male Group I - Animal treated at the dose level of 2000 mg/kg body weight did not result in any signs of toxicity during the study period of 14 days. Sex : Female Group I - Animal treated at the dose level of 2000 mg/kg body weight did not result i

Gross pathology:

Gross pathological examination did not reveal any abnormalities in animals from 2000 mg/kg dose group.

Other findings:

- Other observations: Evaluation of Dermal Reaction
Sex : Male Group I - Animal treated at the dose level of 2000 mg/kg body weight did not result in any skin reaction during the study period of 14 days.
Sex : Female Group I - Animal treated at the dose level of 2000 mg/kg body weight did not result in any skin reaction during the study period of 14 days.

Table No. I

Summary of Clinical Signs of Toxicity and Mortality

Test System : Sprague Dawley Rat

Sex : Male

Group  No.	Dose mg/kg	Observed Signs	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No clinical signs observed	5	1 - 5	Day 0 - Day 14	0/5

Sex : Female

Group  No.	Dose mg/kg	Observed Signs	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No clinical signs observed	5	6 - 10	Day 0 - Day 14	0/5

 

 

Table No. II

Summary of Evaluation of Dermal Reaction

Test System : Sprague Dawley Rat

Sex : Male 

Group  No.	Dose mg/kg	Dermal Reaction	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No dermal reaction observed	5	1 - 5	Day 0 - Day 14	0/5

 

Sex : Female

 

Group  No.	Dose mg/kg	Dermal Reaction	Total Number of Animals	Animal Nos.	Period of signs in days  From - to	Mortality
I	2000	No dermal reaction observed	5	6 - 10	Day 0 - Day 14	0/5

 

 

Table No.III

Mean Body Weight and Percent Body Weight Gain (g)

Test System : Sprague Dawley Rat

Sex : Male

Group No.	Dose (mg/kg body weight)		Body weight Day 0	Body weight Day 7	% body weight gain day 0-7	Body weight Day 14	% body weight gain day 7- 14	% body weight gain day 0- 14
I	2000	Mean	233.08	257.32	10.39	282.66	9.83	21.25
		± SD	3.28	6.92	1.99	9.26	0.83	2.67

 

Sex : Female

Group No.	Dose (mg/kg body weight)		Body weight Day 0	Body weight Day 7	% body weight gain day 0-7	Body weight Day 14	% body weight gain day 7- 14	% body weight gain day 0- 14
I	2000	Mean	215.88	228.30	5.74	242.96	6.41	12.52
		± SD	3.31	6.20	1.30	7.75	0.62	1.88

 

  

Table No.IV 

Summary of Gross Pathological Findings

Test System : Sprague Dawley Rat

Sex : Male

Group No.	Dose mg/kg	Animal Numbers	Animal Fate	Gross Pathological Findings
I	2000	1 - 5	TS	No abnormality detected

 

 Sex : Female     

Group No.	Dose mg/kg	Animal Numbers	Animal Fate	Gross Pathological Findings
I	2000	6 - 10	TS	No abnormality detected

               

TS = Terminal Sacrifice

Interpretation of results:

other: Not classified

Conclusions:

The LD50 value was considered to be >2000 mg/kg bw, when male and female Sprague Dawley rats were occlusively treated with the given test chemical by dermal application following 14 days of observation period according to OECD Guideline 402 (Acute Dermal Toxicity).

Executive summary:

The reported study was designed and conducted to determine the acute dermal toxicity profile of the given test chemical as per OECD Guideline 402 (Acute Dermal Toxicity) in Sprague Dawley rats.

The test item was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days.

Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment.

Hence, it was  concluded  that  the  LD50 value was considered to be >2000 mg/kg bw, when male and female Sprague Dawley rats were occlusively treated with the given test chemical by dermal application following 14 days of observation period according to OECD Guideline 402 (Acute Dermal Toxicity).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Data is Klimisch 1 and from study report.

Additional information

Acute oral toxicity:

In different studies, the given 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 for test chemical. The studies are summarized as below -

 

The reported study was designed and conducted to determine the acute oral toxicity profile of the given test chemical as per OECD Guideline 401 (Acute Oral Toxicity) and Federal Register Vol 50 no 188, Part II, 27 September 1985 in male and female Sprague-Dawley rats.

The given test chemical (Purity 100%) was dissolved in 1% methylcellulose and administered as 10 mL/kg bw via oral gavage route.

In pre-test: 2/sex/dose male and female Sprague-Dawley rats were treated with the given test chemical at the dose concentration of 800, 1600 and 5000 mg/kg bw. Animals were observed for mortality for 5 days. Necropsy was performed only on animals that died. All animals died at 1600 and 5000 mg/kg bw on day 1. At 800 mg/kg bw 1 male died on day 1.

In main test: 5/sex/dose male and female Sprague-Dawley rats were treated with the given test chemical at the dose concentration of 500, 800 and 1260 mg/kg bw. Animals were observed for mortality daily twice (and at regular intervals on day 1). Body weight was observed on day 1, 8 and 15. Necropsy of survivors performed only on animals that died. Clinical signs were observed daily. LD50 value was calculated by the method of probit analysis (Finney).

Mortality was observed as – In males: At 500 mg/kg bw 2/5 before day 4; At 800 mg/kg bw 5/5 before day 3; At 1260 mg/kg bw 4/5 on day 1. In females: At 500 mg/kg bw 0/5 before day 4; At 800 mg/kg bw 4/5 on day 1; At 1260 mg/kg bw 5/5 on day 1. Clinical signs like, piloerection, hunched posture, waddling, decreased respiratory rate and pallor of the extremities in all animals and Ptosis, prostrate and facial swelling were observed less frequently in treated animals. Body weight change was observed for survivors within normal ranges. No abnormalities were observed after necropsy.

Under the condition of the study, the acute oral toxicity dose (LD50) value was considered to be 627 mg/kg bw, with 95% confidence limit of 425-783 mg/kg bw in combined male and female rats; 578 mg/kg bw, with 95% confidence limit of 329-787 mg/kg bw in male rats and 685 mg/kg bw, with 95% confidence limit of 437-983 mg/kg bw in female rats.

 

The above study report is supported with another study mentioned in study report for the given test chemical. The reported study was designed and conducted to determine the acute oral toxicity profile as per OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method) in Sprague Dawley rats.

Initially, three female animals were treated at the dose level of 300 mg/kg body weight of the test item (Step - I). Administration of the test item at 300 mg/kg resulted in ptosis, distension, reduced locomotor activity, ataxic gait and tremors with onset at 10 minutes to 2 hours after the dosing. As no mortality was observed at 24 hours after the dosing, three female animals were added to the study and treated with the same dose of 300 mg/kg of the test item (Step - II). Administration of the test item at 300 mg/kg resulted in ptosis, distension, reduced locomotor activity, ataxic gait and tremors with onset at 30 minutes to 4 hours after the dosing. One animal died on day 1 after the dosing. One mortality was observed at 300 mg/kg dose group, hence additional three female animals were treated with the higher dose of 2000 mg/kg of the test item (Step - I). Administration of the test item at 2000 mg/kg resulted in distension, piloerection, reduced locomotor activity, ataxic gait, tremors and convulsions with onset at 5 to 30 minutes after the dosing. Three animals died at 1 hour after the dosing.

All surviving animals from 300 mg/kg dose group exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities in found dead as well as terminally sacrificed animals from 300 mg/kg and 2000 mg/kg dose groups.

Under the condition of this, the lethal concentration (LD50) value for acute oral toxicity test was considered in between 300-2000 mg/kg bw, when female Sprague Dawley rats were treated with the given test chemical orally via gavage according to OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method).

 

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

 

Acute Inhalation Toxicity:

The acute inhalation toxicity study need not be conducted because exposure to humans via inhalation route is not likely taking into account due to the low vapour pressure of the test chemical, which is reported to be 0.00122 Pa. Thus, exposure to inhalable dust, mist and vapour of the chemical is highly unlikely. Therefore this study is considered for waiver.

Acute Dermal Toxicity:

The reported study was designed and conducted to determine the acute dermal toxicity profile of the given test chemical as per OECD Guideline 402 (Acute Dermal Toxicity) in Sprague Dawley rats.

The test item was applied to shorn skin of 5 male and 5 female animals at 2000 mg/kg body weight. Administration of the test item at 2000 mg/kg did not result in any skin reaction at the site of application during the study period of 14 days.

Administration of the test item did not result in any signs of toxicity and mortality during the study period of 14 days. Animals exhibited normal body weight gain through the study period of 14 days. Gross pathological examination did not reveal any abnormalities attributable to the treatment.

Hence, it was  concluded  that  the  LD50 value was considered to be >2000 mg/kg bw, when male and female Sprague Dawley rats were occlusively treated with the given test chemical by dermal application following 14 days of observation period according to OECD Guideline 402 (Acute Dermal Toxicity).

 

Justification for classification or non-classification

Based on the above studies for the test chemical, it can be concluded that LD50 value is between 300-2000 mg/kg bw, for acute oral toxicity and LD50 value is >2000 mg/kg bw, for acute dermal toxicity. Thus, comparing this range and value with the criteria of CLP regulation, the given test chemical can be classified in “Category 4” for acute oral toxicity and cannot be classified for acute dermal toxicity. For acute inhalation toxicity wavier was added so, not possible to classify.