Ethyl isovalerate

Endpoint summary

Description of key information

The test item has a low acute toxicity by the oral and dermal route.

In rats, the LD50 value via the oral route is > 5000 mg/kg bw (value derived from Read -across compound 3 -methylbutyl isovalerate). In consideration of the molecular weight of both substances (172.27 and 130.18 g/mol), the corrected LD50 for Ethyl isovalerate is > 3778.66 mg/kg.

In rats, the LD50 value via the dermal route is > 2000 mg/kg bw (value derived from Read -across compound ethyl propionate). In consideration of the molecular weight of both substances (102.13 and 130.18 g/mol), the corrected LD50 for the target substance is >2548mg/kg.

No abnormalities were observed during the studies.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-03-16 to 2016-07-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The read across justification is included as an attachment to section 13.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD (SD), SPF

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8 weeks old
- Weight at study initiation: 176.3-195.3 g
- Fasting period before study:animals were fasted overnight, approximately 16 hours prior to dosing
- Housing:cage in an animal room
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: for four days after three days of quarantine (including health examiniation)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.5-24.0 °C (measured), permissible range 19-25 °C
- Humidity (%): 43.5-58-5% (measured) permissible range 30-70 %
- Air changes (per hr): 10-15 clean, fresh, filterd air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 500 mg/mL
- Lot/batch no. (if required): MKBS6944V

MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: due to the low expected toxicity of the test substance a starting dose of 5,000 mg/kg was selected.

Doses:

Step 1: starting dose of 5,000 mg/kg test substance was administered to one animal
Step 2: two animals were administered the test substance at 5,000 mg/kg, becasue there was no dead animal at 5,000 mg/kg (step 1)

No. of animals per sex per dose:

Step 1 : 1 animal
Step 2: 2 animals

Control animals:

no

Details on study design:

- Duration of observation period following administration:14 days
- Frequency of observations and weighing: observations for mortality, clinical signs, general conditions at 30 minutes after dosing and at 1,2,4,6 hours after dosing on day 0 and once daily thereafter for 14 days; body weight was recorded prior to dosing on day 0 and on day 1, 3,7, and on day of necropsy, day 14
- Necropsy of survivors performed: yes
- Other examinations performed: no histopathology, since no gross findings were obsereved at necropsy.

Statistics:

Statistical analysis was not performed. Mean scores and values are determined.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals at 5,000 mg/kg survived the duration of the study. There were no effects on the mortality. Refer to Table 1.

Clinical signs:

other: Mucous stool was observed in one animal at 5,000 mg/kg on Day 1 after dosing and it disappeared on Day 2 after dosing. Therefore, it was considered to be a test substance-related temporary change. Refer to table 2.

Gross pathology:

No gross visible evidence of morphological abnormalities was observed in any animal at 5,000 mg/kg.

Table 1: Summary of Mortality

Step / Dose (mg/kg)	No. of animals	Days after dosing															Mortality
		0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
Step 1/ 5,000	1	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/1
Step 2/ 5,000	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/2

 

Table 2: Individual Clinical Signs

Step / Dose (mg/kg)	Animal ID	Clinical sign	Hours (Day 0) after dosing
			0.5	1	2	4	6
Step 1/ 5,000	2101		-	-	-	-	-
Step 2/ 5,000	2201		-	-	-	-	-
	2202		-	-	-	-	-

 

Step / Dose (mg/kg)	Animal ID	Clinical sign	Days after dosing
			0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
Step 1/ 5,000	2101		-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
Step 2/ 5,000	2201		-	-	-	-	-	-	-	-	-	-	-	-	-	-	-
	2202	Mucous stool	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-

-: No observable abnormality

+: Observable abnormality

Table 3. Individual Body Weights

Step/Dose (mg/kg)	Animal ID	Days after dosing					Gain 0 ~ 14
		0	1	3	7	14
Step 1 5,000	2101	176.3	185.9	202.0	212.9	234.9	58.6
Step 2 5,000	2201	184.6	193.8	213.4	223.8	227.5	42.9
	2202	195.3	198.9	214.1	228.6	235.5	40.2
	Mean	190.0	196.4	213.8	226.2	231.5	41.6
	S.D.	7.6	3.6	0.5	3.4	5.7	1.9
	N	2	2	2	2	2	2

 

 

Table 4. Individual Body Weights during an Acclimation Period

Animal ID	Temporary Animal ID	Receipt	Group assignment
2101	2002	170.9	198.0
2201 2202	2001	174.3	192.5
	2004	180.4	204.4
	2003	183.9	211.3
	Mean	177.4	201.6
	S.D.	5.9	8.1
	N	4	4

 

 

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the result of the acute oral toxicity study in Sprague-dawley rats, the test substance has a LD50 value >5000 mg/kg bw. Therefore, it was not classified according to CLP.

Executive summary:

The purpose of this study was to assess the potential toxicity of the test substance following a single oral dose administration to female Sprague-Dawley rats and to classify the test substance under GHS classification.

 

Two dose groups were designed as Steps 1 and 2 at 5,000 mg/kg. Step 1 consisted of one female and Step 2 consisted of two females. All animals were monitored for clinical signs and body weight changes during the 14-day observation period after administration. They were subjected to gross necropsy at the end of the observation period.

 

There were no deaths of animals at 5,000 mg/kg. Mucous stool was observed in an animal on Day 1 after dosing and it disappeared on Day 2 after dosing. A tendency to suppress body weight gain was observed in animals on Day 1 after dosing. Then, these animals returned to normal on Day 3. No test substance-related effects were observed in necropsy findings in any animal.

 

Based on the result of the acute oral toxicity study in Sprague-Dawley rats, the test substance was not classified according to the GHS classification and the median lethal dose derived was: LD50 cut off> 5,000 mg/kg b.w.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

3 778.66 mg/kg bw

Quality of whole database:

The key study has been identified as reliability 1: reliable without restrictions. However, these data have been scored as reliability 2: reliable with restrictions when used for read across to the target test substance. A supporting study, based on the test substance, has been identified as reliability 2, reliable with restrictions as it was a well conducted and reported study but did not follow published protocols.One further supporting study, based on the test substance, has been identified as reliability 4, due to the limited available data.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted using a read across substance

Justification for type of information:

The read across justification is included as an attachement to Iuclid section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

other: 3 -methylbutyl isovalerate

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute dermal toxicity study the LD50 for the source substance 3 -methylbutyl isovalerate was >2000 mg/kg bw in rats. In consideration of the moleculoar weight of both substances (130,18 and 102.13 g/mol), the corrected LD50 for the target substance is > 2549 mg/kg bw. Therefore, using a read-across approach, the target substance was not classified according to CLP classification.

Executive summary:

The acute dermal toxicity of the target substance was predicted from the source substance (see read-across justification). In an acute dermal toxicity study the LD50 for the source substance was >2000 mg/kg bw in rats. In consideration of the moleculoar weight of both substances (130.18 and 102.13 g/mol), the corrected LD50 value for the target substance is >2549 mg/kg bw. Therefore, using a read-across approach, the target substance was not classified under CLP classification.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 548 mg/kg bw

Quality of whole database:

The key source study has been identified as reliability 1: reliable without restrictions. However, these data have been scored as reliability 2: reliable with restrictions when used for read across to the target test substance. The other supporting study, based on the test substance itself, has been identified as reliability 4, due to the limited available data.

Additional information

In the supporting acute oral toxicity studies in rats using the test substance, an LD50 of >5000 mg/kg bw was determined. In the supporting acute dermal toxicity study an LD50 of >5000 mg/kg bw in rabbits was determined.

Justification for classification or non-classification

Based on the available results, the test substance is not classified for acute oral and dermal toxicity according to Regulation (EC) No 1272/2008.