N,N-diethyl-3-oxobutyramide

Endpoint summary

Description of key information

Acute oral toxicity: 

Acute oral toxicity dose (LD50) of target chemical N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) was considered based on experimental study, the LD50 cut-off value was considered to be 5000 mg/kg in rats. The study concluded that the LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute oral toxicity.

Acute Inhalation toxicity: 

Acute Inhalation toxicity dose (LC50) for N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) was considered based on data available for the structurally and functionally similar read across chemicals. The LC50 value is >5 mg/L. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute inhalation toxicity.

Acute Dermal toxicity: 

Acute Dermal toxicity dose (LD50) for N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) was considered based on experimental study conducted on rats, the LD50 value considered to be >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide 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:

guideline study

Justification for type of information:

Data is from experimental report.

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

The aim of this study was to assess the toxicity potential of Diethylacetoacetamide (DEAAA) (CAS No. 2235-46-3) after single oral administration in Wistar Rats and an observation period of 14 days

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Specific details on test material used for the study:

- IUPAC Name: N,N-diethyl-3-oxobutyramide- InChI: 1S/C8H15NO2/c1-4-9(5-2)8(11)6-7(3)10/h4-6H2,1-3H3- Smiles: N(C(CC(C)=O)=O)(CC)CC- Molecular formula :C8H15NO2- Molecular weight :157.212 g/mol- Substance type:Organic- Physical state:Pale yellow clear liquid- Lot/batch No.: 31- Expiration date of the lot/batch: May 03, 2016

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: National Institute of Biosciences Pune- Females (if applicable) nulliparous and non-pregnant:yes- Age at study initiation: 9 - 12 weeks- Weight at study initiation: Minimum: 120 gm ;Maximum: 150 gm (Individual body weights were within ± 20 % prior to treatment after overnight fasting)- Fasting period before study: Rat were foasted overnight - Housing:Group of three animals were housed in polycarbonate cages (size 37 [cm] x 21 [cm], height 20 [cm])- Diet (e.g. ad libitum): All animals were provided conventional laboratory rodent diet, ad libitum- Water (e.g. ad libitum):Aqua guard filtered tap water was provided ad libitum via drinking bottles.- Acclimation period:Animal nos. 01-03 was acclimatized for 8 days, 04-06 for 11 days, 07-09 for 18 days and 10-12 for 8 days prior to administration of the test item. ENVIRONMENTAL CONDITIONS - Temperature (°C): Minimum: 19.30 °C; Maximum: 23.90 °C - Humidity (%): Minimum: 50.80%; Maximum: 66.50% - Air changes (per hr): More than 12 changes per hour - Photoperiod (hrs dark / hrs light): 12 hour light and 12 hour dark IN-LIFE DATES: From: November 09, 2015 To:December 22, 2015

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE - Concentration in vehicle: 300 mg/kg and 2000 mg/kg - Amount of vehicle (if gavage):10 ml/kg - Justification for choice of vehicle:Corn oil was selected as a vehicle based on solubility testing - Lot/batch no. (if required): MR301015 DOSAGE PREPARATION (if unusual):Vehicle (Corn oil) was added to the weighed quantity of test item (300 mg and 2000 mg) slowly and mixed well. Transferred the formulation to the measuring cylinder and made the final volume up to 10 ml. Hence, stock dose concentration was achieved as 30 mg/ml and 200 mg/ml. The test item was miscible in corn oil. The dosing solution was prepared freshly, shortly prior to dose administration. CLASS METHOD (if applicable) - Rationale for the selection of the starting dose:The starting dose level was that, which most likely to produce mortality in some of the dosed animals. The starting dose level was selected as 300 mg/kg body weight as no information was available to conduct the study.

Doses:

300 and 2000 mg/kg bw

No. of animals per sex per dose:

Total = 12 Females (Group of 3 animals/dose)

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days - Frequency of observations and weighing:After test item administration, individual animals were frequently observed at 30 minutes, 1, 2, 3 and 4 hours post dosing on day 0 (day of dosing). Subsequently, all the animals were observed once a day during the 14 day observation period.All surviving animals were observed twice daily (morning and evening) for morbidity and mortality, throughout the acclimatization and study period.All the rats were weighed on days 0 (prior to dosing), 7 and 14. - Necropsy of survivors performed: yes - Other examinations performed: All the animals were observed for external and internal gross pathology.

Statistics:

not specified

Preliminary study:

not specified

Sex:

female

Dose descriptor:

LD50 cut-off

Effect level:

5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality was observed in animals treated with 300 and 2000 mg/kg body weight throughout the 14 days observation period

Clinical signs:

other: At 300 and 2000 mg/kg body weight, all the animals were observed normal throughout the experimental period

Gross pathology:

During external and internal gross necropsy examination, terminally sacrificed animals treated with 300 and 2000 mg/kg body weight showed no abnormalities

Other findings:

not specified

Table 1: Individual Animal Body Weight (g) andBody Weight Changes(%)

Sex:Female

Animal No.	Group/ Dose (mg/kg body weight)		Body Weight (gram)			Body Weight Change (%)
		Dose Volume* (ml)	Day 0	Day 7	Day 14	Day 0-7	Day 0-14
01	G1/ 300	1.5	145	163	198	12.41	36.55
02		1.5	150	168	200	12.00	33.33
03		1.4	144	159	186	10.42	29.17
04		1.3	134	159	182	18.66	35.82
05		1.4	140	167	173	19.29	23.57
06		1.3	132	155	181	17.42	37.12
07	G2/ 2000	1.2	120	143	192	19.17	60.00
08		1.4	142	177	210	24.65	47.89
09		1.4	139	168	200	20.86	43.88
10		1.4	136	156	178	14.71	30.88
11		1.4	142	162	194	14.08	36.62
12		1.4	139	155	171	11.51	23.02

*= Dose volume calculated based on day 0 body weight

 

 

Table 2: Summary of Animal Body Weight (g) and Body Weight Changes (%)

 

Sex:Female

Group/ Dose (mg/kg body weight)		Rats Body Weight (g)			Body Weight Changes (%)
		Day 0	Day 7	Day 14	0-7	0-14
G1/ 300	Mean	140.83	161.83	186.67	15.03	32.59
	SD	6.88	5.08	10.46	3.85	5.30
	n	6	6	6	6	6
G2/ 2000	Mean	136.33	160.17	190.83	17.50	40.38
	SD	8.31	11.72	14.29	4.91	13.11
	n	6	6	6	6	6

Keys:SD = Standard Deviation, n = Number of Animals

Table 3: Individual Animal Clinical Signs and Symptoms

Sex:Female

Animal No.	Group/ Dose (mg/kg body weight)	Hours (Day 0)
		1/2	1	2	3	4
01	G1/ 300	1	1	1	1	1
02		1	1	1	1	1
03		1	1	1	1	1
04		1	1	1	1	1
05		1	1	1	1	1
06		1	1	1	1	1
07	G2/ 2000	1	1	1	1	1
08		1	1	1	1	1
09		1	1	1	1	1
10		1	1	1	1	1
11		1	1	1	1	1
12		1	1	1	1	1

Key: 1 = Normal

Table 3: Individual Animal Clinical Signs and Symptoms (Continued)

 

Sex:Female

 

Animal No.	Group/ Dose (mg/kg body weight)	Days post dosing
		1	2	3	4	5	6	7	8	9	10	11	12	13	14
01	G1/ 300	1	1	1	1	1	1	1	1	1	1	1	1	1	1
02		1	1	1	1	1	1	1	1	1	1	1	1	1	1
03		1	1	1	1	1	1	1	1	1	1	1	1	1	1
04		1	1	1	1	1	1	1	1	1	1	1	1	1	1
05		1	1	1	1	1	1	1	1	1	1	1	1	1	1
06		1	1	1	1	1	1	1	1	1	1	1	1	1	1
07	G2/ 2000	1	1	1	1	1	1	1	1	1	1	1	1	1	1
08		1	1	1	1	1	1	1	1	1	1	1	1	1	1
09		1	1	1	1	1	1	1	1	1	1	1	1	1	1
10		1	1	1	1	1	1	1	1	1	1	1	1	1	1
11		1	1	1	1	1	1	1	1	1	1	1	1	1	1
12		1	1	1	1	1	1	1	1	1	1	1	1	1	1

Key: 1 = Normal

Table 4: Individual Animal Mortality Record

 

Sex:Female

Animal No.	Group/ Dose (mg/kg body weight)	Day of Observation (Day 0 to 14)
		Morning Observation	Evening Observation
01	G1/ 300	No mortality and morbidity	No mortality and morbidity
02		No mortality and morbidity	No mortality and morbidity
03		No mortality and morbidity	No mortality and morbidity
04		No mortality and morbidity	No mortality and morbidity
05		No mortality and morbidity	No mortality and morbidity
06		No mortality and morbidity	No mortality and morbidity
07	G2/ 2000	No mortality and morbidity	No mortality and morbidity
08		No mortality and morbidity	No mortality and morbidity
09		No mortality and morbidity	No mortality and morbidity
10		No mortality and morbidity	No mortality and morbidity
11		No mortality and morbidity	No mortality and morbidity
12		No mortality and morbidity	No mortality and morbidity

Key:TS = Terminal Sacrifice

Table 5: Gross Necropsy Observation

 

Sex:Female                                                                                                                                        

Animal No.	Group/ Dose (mg/kg body weight)	Mode of Death	Gross Observation
			External	Internal
01	G1/ 300	TS	No abnormality detected	No abnormality detected
02		TS	No abnormality detected	No abnormality detected
03		TS	No abnormality detected	No abnormality detected
04		TS	No abnormality detected	No abnormality detected
05		TS	No abnormality detected	No abnormality detected
06		TS	No abnormality detected	No abnormality detected
07	G2/ 2000	TS	No abnormality detected	No abnormality detected
08		TS	No abnormality detected	No abnormality detected
09		TS	No abnormality detected	No abnormality detected
10		TS	No abnormality detected	No abnormality detected
11		TS	No abnormality detected	No abnormality detected
12		TS	No abnormality detected	No abnormality detected

Key : TS = Terminal Sacrifice

Interpretation of results:

other: Not classified

Conclusions:

The LD50 cut-off value was considered to be 5000 mg/kg bw, when female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) via oral gavage route.

Executive summary:

Acute Oral Toxicity Study of N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) was conducted as per OECD No. 423 on 12 female Wistar rats at the dose concentration of 300 and 2000 mg/kg bw. The animals were fasted for minimum 16-17.5 hours prior to dosing and for 4 hours post dosing, feed was withheld but drinking water provided ad libitum. The time intervals between dosing were determined by the onset, duration and severity of toxic signs.3 rats of the first group G1 were dosed with starting dose of 300 mg/kg body weight and the animals did not show any mortality. So another 3 animals of the same group G1 were dosed with 300 mg/kg body weight and no mortality was observed. Next, 3 animals of group G2 were dosed with 2000 mg/kg body weight and no mortality was observed. So, another 3 animals of the same group G2 were dosed with 2000 mg/kg body weight and no mortality was observed. Hence, further dosing was stopped.After test item administration, individual animals were frequently observed at 30 minutes, 1, 2, 3 and 4 hours post dosing on day 0 (day of dosing). Subsequently, all the animals were observed once a day during the 14 day observation period. All surviving animals were observed twice daily (morning and evening) for morbidity and mortality, throughout the acclimatization and study period. All the rats were weighed on days 0 (prior to dosing), 7 and 14.All the animals were observed for external and internal gross pathology.No mortality was observed in animals treated with 300 and 2000 mg/kg body weight throughout the 14 days observation period. At 300 and 2000 mg/kg body weight, all the animals were observed normal throughout the experimental period.Mean body weight of all the animals treated with 300 and 2000 mg/kg body weight were observed with gain on day 7 and 14, as compared to day 0. During external and internal gross necropsy examination, terminally sacrificed animals treated with 300 and 2000 mg/kg body weight showed no abnormalities. Hence, The LD50 cut-off value was considered to be 5000 mg/kg bw, when female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) via oral gavage route.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 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:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Remarks:

experimental data of read across substances

Justification for type of information:

Data for the target chemical is summarized based on the structurally and functionally similar read across chemicals.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: As mentioned below

Principles of method if other than guideline:

WoE report is based on 2 acute inhalation toxicity studies as - WoE-2 and WoE-3. Acute Inhalation toxicity test was carried out to study the effects of the test chemicals on rodents.

GLP compliance:

not specified

Test type:

other: not specified

Limit test:

no

Specific details on test material used for the study:

- IUPAC Name: N,N-diethyl-3-oxobutyramide- InChI: 1S/C8H15NO2/c1-4-9(5-2)8(11)6-7(3)10/h4-6H2,1-3H3- Smiles: N(C(CC(C)=O)=O)(CC)CC- Molecular formula :C8H15NO2- Molecular weight :157.212 g/mol- Substance type:Organic- Physical state:Pale yellow clear liquid

Species:

other: 1. mouse 2. rat

Strain:

other: 1. not specified 2. Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

1. not specified2. TEST ANIMALS- Source: USAEHA's colony- Weight at study initiation: 107±15 gm- Housing: Rats were individually caged and placed in a Wahmann 225 L, dynamic airflow exposure chamber.- Diet (e.g. ad libitum): The laboratory diet for the rats was Formulab ChoW® No. 5008, ad libitum- Water (e.g. ad libitum): ad libitum

Route of administration:

other: 1. inhalation 2. inhalation: aerosol

Type of inhalation exposure:

other: 1. not specified 2. not specified

Vehicle:

other: 1. not specified 2. not specified

Remark on MMAD/GSD:

not specified

Details on inhalation exposure:

1. not specified2. GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION - Exposure apparatus:Wahmann 225 L, dynamic airflow exposure chamber - Exposure chamber volume: 225 L - Method of holding animals in test chamber:Rats were individually caged and placed in chamber - Method of conditioning air:Chamber air was pulled through a glass fiber filter at approximately 2 liters per minute for 5 minutes. - System of generating particulates/aerosols:The test compound was dispersed into the chambers for 4 hours using a Collison Nebulizer - Method of particle size determination: particle-sizing determinations were impossible due to the speed of evaporation of the test compound from the Teflon-coated slides. - Temperature, humidity, pressure in air chamber: The rate of airflow through the chamber as well as temperature was monitored during the exposures. TEST ATMOSPHERE - Samples taken from breathing zone: yes, the actual concentration of test chemical in the animals' breathing zones was measured four times during each exposure (0.5, 1, 2, and 3 hours into the exposure).

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

4 h

Remarks on duration:

not specified

Concentrations:

1. 142000 mg/m³2. 3700, 4260, 5185, 5450, 5480, and 5950 mg/m3

No. of animals per sex per dose:

1. not specified2. 10 rats/sex/dose

Control animals:

other: 1. not specified 2. Yes, 10 rats/sex/dose

Details on study design:

1. not specified2. - Duration of observation period following administration: 14 days, rats were observed during the exposure and for 14 days post exposure.- Frequency of observations and weighing: Body weights were determined on the day of exposure and days 1, 3, 7, and 14 days post exposure.- Necropsy of survivors performed: yes, at the conclusion of each 14-day observation period, the surviving animals were sacrificed by decapitation and internal organs examined for gross abnormalities. Tissues exhibiting gross abnormalities were preserved for future histopathologic examination.

Statistics:

1. not specified2. not specified

Preliminary study:

1. not specified2. not specified

Sex:

not specified

Dose descriptor:

LC50

Effect level:

142 000 mg/m³ air

Based on:

test mat.

Remarks on result:

other: 50% mortality was observed

Sex:

male/female

Dose descriptor:

LC50

Effect level:

5 950 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

1. 50% mortality was observed at 142000 mg/m³.2. Mortality was observed in animals as follows – At 3700 mg/m3 – 1 male and 1 female was died; At 4260 mg/m3 – No mortality was observedAt 5185 mg/m3 – 2 males and 1 female rat was died;At 5450 mg/m3 – 3 males and 2 females were died;At 5480 mg/m3 – 2 male and 4 females were died;At 5950 mg/m3 – 7 males and 8 females were died

Clinical signs:

other: 1. not specified2. not specified

Body weight:

1. not specified2. Significant differences were found between the acute inhalation exposure rat and control rat body weights over the 14-day observation period.

Gross pathology:

1. not specified2. No gross lesions attributable to the inhalation of the test chemical were detected in rats necropsied 14 days after the acute aerosol exposures. No chemically-induced histological lesions were recognized in the tissues microscopically examined.

Other findings:

1. not specified2. not specified

Interpretation of results:

other: Not classified

Conclusions:

According to CLP regulation the test chemical Formaldehyde, oligomeric reaction products with phenol (CAS No. 9003-35-4) cannot be classified for acute inhalation toxicity, as the LC50 value is >5 mg/L (>5000 mg/m3) and in the range of >5000-7570 mg/m3.

Executive summary:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the acute oral toxicity of the test chemical N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3). The studies are as mentioned below:

1. Acute inhalation toxicity study of test chemical was conducted in mice at the dose concentration of 142000 mg/m3. 50% mortality was observed at 142000 mg/m³. Hence, LC50 value was considered to be 142000 mg/m3, when mice were treated with test chemical by inhalation route.

2. Acute inhalation toxicity study of test chemical was conducted in male and female Sprague-Dawley albino rats at the dose concentration of 3700, 4260, 5185, 5450, 5480, and 5950 mg/m3. Rats were individually caged and placed in a Wahmann 225 L, dynamic airflow exposure chamber. The test compound was dispersed into the chambers for 4 hours using a Collison Nebulizer. Rats were observed during the exposure and for 14 days post exposure. Body weights were determined on the day of exposure and days 1, 3, 7, and 14 days post exposure. At the conclusion of each 14-day observation period, the surviving animals were sacrificed by decapitation and internal organs examined for gross abnormalities. Tissues exhibiting gross abnormalities were preserved for future histopathologic examination. The concentrations for the acute aerosol exposures were measured analytically. Mortality was observed in animals as follows – At 3700 mg/m3 – 1 male and 1 female was died; At 4260 mg/m3 – No mortality was observed; At 5185 mg/m3 – 2 males and 1 female rat was died; At 5450 mg/m3 – 3 males and 2 females were died; At 5480 mg/m3 – 2 male and 4 females were died; At 5950 mg/m3 – 7 males and 8 females were died. Significant differences were found between the acute inhalation exposure rat and control rat body weights over the 14-day observation period. No gross lesions attributable to the inhalation of the test chemical were detected in rats necropsied 14 days after the acute aerosol exposures. No chemically-induced histological lesions were recognized in the tissues microscopically examined. Hence, LC50 value was considered to be 5950 mg/m³, when male and female Sprague-Dawley albino rats were treated with test chemical by inhalation route via aerosol for 4 hour exposure.

Thus, based on the above studies on N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) and it’s structurally and functionally read across substances, it can be concluded that LC50 value is >5 mg/L. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute inhalation toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

142 000 mg/m³ air

Quality of whole database:

Data is Klimisch 2 and from authoritative database.

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 report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Principles of method if other than guideline:

The aim of this study was to assess the dermal toxicity of Diethylacetoacetamide (DEAAA) (CAS No. 2235-46-3) after single dose application by dermal route in Wistar rats and 14 day observation period.

GLP compliance:

yes

Test type:

other: Acute Dermal Toxicity

Limit test:

yes

Specific details on test material used for the study:

- IUPAC Name: N,N-diethyl-3-oxobutyramide- InChI: 1S/C8H15NO2/c1-4-9(5-2)8(11)6-7(3)10/h4-6H2,1-3H3- Smiles: N(C(CC(C)=O)=O)(CC)CC- Molecular formula :C8H15NO2- Molecular weight :157.212 g/mol- Substance type:Organic- Physical state:Pale yellow clear liquid

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: In-House Bred- Females (if applicable) nulliparous and non-pregnant: yes- Age at study initiation: young adult animals - Weight at study initiation: Male:Minimum: 214 g and Maximum: 235 g; Female:Minimum: 229 g and Maximum: 259 g - Housing:The animals were housed individually in polycarbonate cages (size 37 [cm] x 21 [cm], height 20 [cm]).- Diet (e.g. ad libitum): All animals were provided conventional laboratory rodent diet, ad libitum. - Water (e.g. ad libitum):Aqua guard filtered tap water was provided via drinking bottles, ad libitum - Acclimation period:All animals were acclimatized to the test conditions for 6 days prior to application of the test item. ENVIRONMENTAL CONDITIONS - Temperature (°C): Minimum: 19.40 °C; Maximum: 23.60 °C - Humidity (%): Minimum: 43.30%; Maximum: 68.10% - Air changes (per hr): More than 12 changes per hour - Photoperiod (hrs dark / hrs light): 12 hour light and 12 hour dark IN-LIFE DATES: From: December 08, 2015 To:December 28, 2015

Type of coverage:

occlusive

Vehicle:

not specified

Details on dermal exposure:

TEST SITE - Area of exposure: clipped dorsal area of rat skin - % coverage: greater than 10% body surface area - Type of wrap if used: Test item was held in contact with the skin with a porous gauze dressing (Approx. 10% of body surface area of rat) and non-irritating tape REMOVAL OF TEST SUBSTANCE - Washing (if done): test item was removed by using distilled water - Time after start of exposure:24-hour

Duration of exposure:

24-hour

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Total = 10 (Five per sex)

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days - Frequency of observations and weighing:After test item administration, individual animals were frequently observed at 1, 2, 3 and 4 hours post dosing on day 0 (day of dosing). Subsequently, all animals were observed once a day during the 14 day observation period for clinical signs. All animals were observed for Local signs/skin reactions (in common with clinical signs) once daily and for mortality and morbidity twice daily.All rats were weighed on days 0 (prior to dosing), 7 and 14. - Necropsy of survivors performed: yes, at the end of 14 day observation period, all the surviving rats were euthanized by overdose of CO2 and subjected to gross pathology examination, for external and internal observations.

Statistics:

No statistical analysis was performed for LD50 calculation since the study was terminated with limit test.

Preliminary study:

not specified

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No mortality was observed

Mortality:

No mortality was observed at limit dose of 2000 mg/kg body weight during the 14 day observation period.

Clinical signs:

other: At 2000 mg/kg, all the animals were observed normal throughout the experimental period.

Gross pathology:

The external and internal gross pathological observation of all terminally sacrificed animals did not show any pathological abnormality.

Other findings:

not specified

Table 1: Dose Volume (ml), Individual Animal Body Weight (g) andBody Weight Changes(%)

 

Dose:2000 mg/ kg bodyweight                   Group:G1                           Density:0.98475

Animal No.	Sex	Dose Volume* (ml)	Body Weight (gram)			Body Weight Change (%)
			Day 0	Day 7	Day 14	Day 0-7	Day 0-14
01	Male	0.44	219	235	259	7.31	18.26
02		0.43	214	229	251	7.01	17.29
03		0.48	235	246	267	4.68	13.62
04		0.45	221	245	278	10.86	25.79
05		0.43	214	239	266	11.68	24.30
06	Female	0.51	252	256	263	1.59	4.37
07		0.52	258	270	281	4.65	8.91
08		0.51	249	256	264	2.81	6.02
09		0.53	259	276	285	6.56	10.04
10		0.47	229	238	249	3.93	8.73

Key: * = based on the test item density and day 0 body weight

Table 2:Summaryof Animal Body Weight (g) and Body Weight Changes (%)

Dose: 2000 mg/kg body weight                                                                                            Group: G1

Sex		Body Weight (gram)			Body Weight Changes (%)
		Day 0	Day 7	Day 14	Day 0-7	Day 0-14
Male	Mean	220.60	238.80	264.20	8.31	19.85
	SD	8.62	7.09	10.03	2.90	5.07
	n	5	5	5	5	5
Female	Mean	249.40	259.20	268.40	3.91	7.62
	SD	12.14	14.74	14.66	1.88	2.34
	n	5	5	5	5	5

Keys: SD= Standard deviation, n = Number of animals

Table 3: Individual Animal Clinical Signs and Symptoms

 

Dose:2000 mg/kg body weight                                                                                            Group:G1

Animal No.	Sex	Hour(s) - Day 0				Day(s)
		1	2	3	4	1	2	3	4	5	6	7
01	Male	1	1	1	1	1	1	1	1	1	1	1
02		1	1	1	1	1	1	1	1	1	1	1
03		1	1	1	1	1	1	1	1	1	1	1
04		1	1	1	1	1	1	1	1	1	1	1
05		1	1	1	1	1	1	1	1	1	1	1
06	Female	1	1	1	1	1	1	1	1	1	1	1
07		1	1	1	1	1	1	1	1	1	1	1
08		1	1	1	1	1	1	1	1	1	1	1
09		1	1	1	1	1	1	1	1	1	1	1
10		1	1	1	1	1	1	1	1	1	1	1

 

Animal No.	Sex	Day(s)
		8	9	10	11	12	13	14
01	Male	1	1	1	1	1	1	1
02		1	1	1	1	1	1	1
03		1	1	1	1	1	1	1
04		1	1	1	1	1	1	1
05		1	1	1	1	1	1	1
06	Female	1	1	1	1	1	1	1
07		1	1	1	1	1	1	1
08		1	1	1	1	1	1	1
09		1	1	1	1	1	1	1
10		1	1	1	1	1	1	1

Key: 1 = Normal

Table 4: Individual Animal Mortality Record

 

Dose:2000 mg/kg body weight                                                                                           Group:G1

Animal No.	Sex	Days of Observation (0 to 14)
		Morning Observations	Evening Observations
01	Male	No mortality and morbidity	No mortality and morbidity
02		No mortality and morbidity	No mortality and morbidity
03		No mortality and morbidity	No mortality and morbidity
04		No mortality and morbidity	No mortality and morbidity
05		No mortality and morbidity	No mortality and morbidity
06	Female	No mortality and morbidity	No mortality and morbidity
07		No mortality and morbidity	No mortality and morbidity
08		No mortality and morbidity	No mortality and morbidity
09		No mortality and morbidity	No mortality and morbidity
10		No mortality and morbidity	No mortality and morbidity

Table 5: GrossNecropsyObservation

 

 Dose:2000 mg/kg body weight               Group:G1             Mode of Death:Terminal Sacrifice

Animal No.	Sex	Gross Observation
		External	Internal
01	Male	No abnormality detected	No abnormality detected
02		No abnormality detected	No abnormality detected
03		No abnormality detected	No abnormality detected
04		No abnormality detected	No abnormality detected
05		No abnormality detected	No abnormality detected
06	Female	No abnormality detected	No abnormality detected
07		No abnormality detected	No abnormality detected
08		No abnormality detected	No abnormality detected
09		No abnormality detected	No abnormality detected
10		No abnormality detected	No abnormality detected

Interpretation of results:

other: Not classified

Conclusions:

The LD50 was considered to be >2000 mg/kg bw, when male and female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) by dermal application.

Executive summary:

Acute Dermal Toxicity Study was conducted using N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) as per OECD No.402 in 10 male and female healthy young adult Wistar rats which were randomly selected and used for conducting acute dermal toxicity study at the concentration of 2000 mg/kg bw. Rats free from injury and irritation of skin were selected for the study. 24 hours prior to dermal application of test item, approximately 10% of body surface area of each rat was clipped. A limit dose of 2000 mg/ kg body weight based on the test item density (0.98475) and latest body weight was applied by single dermal application and observed for 14 days after treatment. On test day 0, test item was applied directly on the intact skin of clipped area of rats; the porous gauze dressing was put on to the intact skin of clipped area. This porous gauze dressing was covered with a non-irritating tape. After the 24-hour application period, the dressings were removed and the skin was gently wiped with distilled water. The skin reactions were assessed.The animals were observed daily for mortality and clinical signs, during the acclimatization period and post dosing till the termination. All animals were observed for clinical signs at approximately 1, 2, 3 and 4 hours after treatment on day 0 and once daily during test days 1, 14. Mortality was recorded after application on test day 0 and twice daily during days 1-14 (at least once on the day of sacrifice). Local signs / Skin reactions were observed daily from test days 1-14. Body weights were recorded on day 0 (prior to application) and on day 7 and 14. All animals were necropsied and examined macroscopically.No mortality was observed in any animal till the end of the experimental period.At 2000 mg/kg, all the animals were observed normal throughout the experimental period. Mean body weight was observed with gain on day 7 and 14 of male and female animals, as compared to day 0. The external and internal gross pathological observation of all terminally sacrificed animals did not show any pathological abnormality. Hence, LD50 was considered to be >2000 mg/kg bw, when male and female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) by dermal application.

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 experimental report.

Additional information

Acute oral toxicity:

In different experimental studies, N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) 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 N,N-diethyl-3-oxobutyramide. The studies are summarized as below –

Acute Oral Toxicity Study of N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) was conducted as per OECD No. 423 on 12 female Wistar rats at the dose concentration of 300

and 2000 mg/kg bw. The animals were fasted for minimum 16-17.5 hours prior to dosing and for 4 hours post dosing, feed was withheld but drinking water provided ad libitum. The time intervals between dosing were determined by the onset, duration and severity of toxic signs.3 rats of the first group G1 were dosed with starting dose of 300 mg/kg body weight and the animals did not show any mortality. So another 3 animals of the same group G1 were dosed with 300 mg/kg body weight and no mortality was observed. Next, 3 animals of group G2 were dosed with 2000 mg/kg body weight and no mortality was observed. So, another 3 animals of the same group G2 were dosed with 2000 mg/kg body weight and no mortality was observed. Hence, further dosing was stopped.After test item administration, individual animals were frequently observed at 30 minutes, 1, 2, 3 and 4 hours post dosing on day 0 (day of dosing). Subsequently, all the animals were observed once a day during the 14 day observation period. All surviving animals were observed twice daily (morning and evening) for morbidity and mortality, throughout the acclimatization and study period. All the rats were weighed on days 0 (prior to dosing), 7 and 14.All the animals were observed for external and internal gross pathology.No mortality was observed in animals treated with 300 and 2000 mg/kg body weight throughout the 14 days observation period. At 300 and 2000 mg/kg body weight, all the animals were observed normal throughout the experimental period.Mean body weight of all the animals treated with 300 and 2000 mg/kg body weight were observed with gain on day 7 and 14, as compared to day 0. During external and internal gross necropsy examination, terminally sacrificed animals treated with 300 and 2000 mg/kg body weight showed no abnormalities. Hence, The LD50 cut-off value was considered to be 5000 mg/kg bw, when female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) via oral gavage route.

The above experimental study is further supported by the study mentioned in publication, handbook, authoritative database and secondary source for the target chemical N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3). Acute oral toxicity study was conducted in groups of 5 male Carworth–Wistar rats at the dose concentration of 4760 (3390-6680) mg/kg bw. The doses are different in logarithmic order by a factor of 2. The test chemical was given undiluted via oral gavage route. After administration of the substance, the animals became 14 days long observed. The statistically probable ste LD50 value and its confidence interval according to the method of Thompson (Bacteriol Rev.11, 1947, p.115) using of the Tables of Weil (Biometrics 8, 1952, p. 249). 50% mortality was observed at 4760 mg/kg bw. Therefore, LD50 value was considered to be 4760 mg/kg bw, with 95% confidence limit of 3390-6680 mg/kg bw, when groups of 5 male Carworth–Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) via oral gavage route.

Thus, based on the above studies on N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3), it can be concluded that LD50 value is >2000 mg/kg bw. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute oral toxicity.

Acute Inhalation Toxicity:

Data available for the structurally and functionally similar read across chemicals has been reviewed to determine the acute oral toxicity of the test chemical N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3). The studies are as mentioned below:

1. Acute inhalation toxicity study of test chemical was conducted in mice at the dose concentration of 142000 mg/m3. 50% mortality was observed at 142000 mg/m³. Hence, LC50 value was considered to be 142000 mg/m3, when mice were treated with test chemical by inhalation route.

2. Acute inhalation toxicity study of test chemical was conducted in male and female Sprague-Dawley albino rats at the dose concentration of 3700, 4260, 5185, 5450, 5480, and 5950 mg/m3. Rats were individually caged and placed in a Wahmann 225 L, dynamic airflow exposure chamber. The test compound was dispersed into the chambers for 4 hours using a Collison Nebulizer. Rats were observed during the exposure and for 14 days post exposure. Body weights were determined on the day of exposure and days 1, 3, 7, and 14 days post exposure. At the conclusion of each 14-day observation period, the surviving animals were sacrificed by decapitation and internal organs examined for gross abnormalities. Tissues exhibiting gross abnormalities were preserved for future histopathologic examination. The concentrations for the acute aerosol exposures were measured analytically. Mortality was observed in animals as follows – At 3700 mg/m3 – 1 male and 1 female was died; At 4260 mg/m3 – No mortality was observed; At 5185 mg/m3 – 2 males and 1 female rat was died; At 5450 mg/m3 – 3 males and 2 females were died; At 5480 mg/m3 – 2 male and 4 females were died; At 5950 mg/m3 – 7 males and 8 females were died. Significant differences were found between the acute inhalation exposure rat and control rat body weights over the 14-day observation period. No gross lesions attributable to the inhalation of the test chemical were detected in rats necropsied 14 days after the acute aerosol exposures. No chemically-induced histological lesions were recognized in the tissues microscopically examined. Hence, LC50 value was considered to be 5950 mg/m³, when male and female Sprague-Dawley albino rats were treated with test chemical by inhalation route via aerosol for 4 hour exposure.

Thus, based on the above studies on N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) and it’s structurally and functionally read across substances, it can be concluded that LC50 value is >5 mg/L. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute inhalation toxicity.

Acute Dermal toxicity:

Acute Dermal Toxicity Study was conducted using N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) as per OECD No.402 in 10 male and female healthy young adult Wistar rats which were randomly selected and used for conducting acute dermal toxicity study at the concentration of 2000 mg/kg bw. Rats free from injury and irritation of skin were selected for the study. 24 hours prior to dermal application of test item, approximately 10% of body surface area of each rat was clipped. A limit dose of 2000 mg/ kg body weight based on the test item density (0.98475) and latest body weight was applied by single dermal application and observed for 14 days after treatment. On test day 0, test item was applied directly on the intact skin of clipped area of rats; the porous gauze dressing was put on to the intact skin of clipped area. This porous gauze dressing was covered with a non-irritating tape. After the 24-hour application period, the dressings were removed and the skin was gently wiped with distilled water. The skin reactions were assessed.The animals were observed daily for mortality and clinical signs, during the acclimatization period and post dosing till the termination. All animals were observed for clinical signs at approximately 1, 2, 3 and 4 hours after treatment on day 0 and once daily during test days 1, 14. Mortality was recorded after application on test day 0 and twice daily during days 1-14 (at least once on the day of sacrifice). Local signs / Skin reactions were observed daily from test days 1-14. Body weights were recorded on day 0 (prior to application) and on day 7 and 14. All animals were necropsied and examined macroscopically.No mortality was observed in any animal till the end of the experimental period.At 2000 mg/kg, all the animals were observed normal throughout the experimental period. Mean body weight was observed with gain on day 7 and 14 of male and female animals, as compared to day 0. The external and internal gross pathological observation of all terminally sacrificed animals did not show any pathological abnormality. Hence, LD50 was considered to be >2000 mg/kg bw, when male and female Wistar rats were treated with N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) by dermal application. Thus, comparing this value with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute dermal toxicity.

Justification for classification or non-classification

Based on the above experimental studies on N,N-diethyl-3-oxobutyramide (CAS no: 2235-46-3) and it’s structurally and functionally read across substances, it can be concluded that LD50 value is >2000 mg/kg bw for acute oral and dermal toxicity; and LC50 value is >5 mg/L for acute inhalation toxicity. Thus, comparing these values with the criteria of CLP regulation, N,N-diethyl-3-oxobutyramide cannot be classified for acute oral, dermal and inhalation toxicity.