3-methylbutyl butyrate

Endpoint summary

Description of key information

The test item is considered to have 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 the read-across compound isoamyl isovalerate). In consideration of the molecular weight of the source and target substances (172.27 and 158.24 g/mol), the corrected LD50 for the target substance is > 4592.8 mg/kg bw. Furthermore, a supporting oral toxicity study with the test substance isoamyl butyrate supports this result (LD50 value >5000 mg/kg bw). Mortality after dermal exposure to the test item is not expected as a supporting acute dermal toxicity study as well as the in vivo acute oral toxicity study (value derived from read-across compound isoamyl isovalerate) showed no effects up to 5000 mg/kg bw and 4592.8 mg/kg bw, respectively. For this reason, a further acute dermal toxicity study will be waived.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

The read-across justification is included as an attachment in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

other: 3-methylbutyl isovalerate

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute oral toxicity study the LD50 for the source substance 3 -methylbutyl isovalerate was >5000 mg/kg bw in rats. In consideration of the molecular weight of both substances (172.27 and 158.24 g/mol), the corrected LD50 for the target substance is > 4592.8 mg/kg. Therefore, using a read-across approach, the target substance was not classified according to CLP classification.

Executive summary:

The acute oral toxicity of the target substance was predicted from the source substance (see read-across justification). In an acute oral toxicity study the LD50 for the source substance was >5000 mg/kg bw in rats. In consideration of the molecular weight of both substances (172.27 and 158.24 g/mol), the corrected LD50 for the target substance is > 4592.8 mg/kg bw. Therefore, using a read-across approach, the target substance was not classified according to CLP classification.

Reference 2

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

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 an 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:

4 592.8 mg/kg bw

Quality of whole database:

The key study was assigned 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 supporting study, based on the test substance, has been identified as reliability 4, due to the limited available data.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1976-08-02

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

GLP compliance:

not specified

Limit test:

yes

Species:

rabbit

Strain:

not specified

Sex:

not specified

Type of coverage:

not specified

Vehicle:

not specified

Doses:

5000 mg/kg body weight

No. of animals per sex per dose:

10 animals (no sex specified)

Control animals:

not specified

Details on study design:

Duration of observation period following administration: 14 days (not clear if only one administration)

Key result

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

0/10

Clinical signs:

other: diarrhea in 2

Interpretation of results:

GHS criteria not met

Conclusions:

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

Executive summary:

In an acute dermal toxicity study in rabbits, it was found that the LD50 (rabbits) value >5000 mg/kg bw. Therefore, the test substance was not classified under CLP.

Reference 2

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance does not meet the criteria for classification as acute toxicity or STOT SE by the oral route and no systemic effects have been observed in in vivo studies with dermal exposure (e.g. skin irritation, skin sensitisation)

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
An in vivo acute dermal toxicity study is available which showed no acute effects up to 5000 mg/kg bw. Although the study is poorly documented, it can be assumed that no mortality after dermal exposure is to be expected from the test item. Furthermore, an in vivo acute oral toxicity study showed no effects up to 5000 mg/kg bw, supporting this conclusion.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Quality of whole database:

The supporting study, based on the test substance, has been identified as reliability 4, due to the limited available data.

Additional information

Acute oral toxicity, key study (read-across)

The acute oral toxicity of the target substance isoamyl butyrate was predicted from the source substance isoamyl isovalerate. The purpose of the acute oral toxicity study with isoamyl isovalerate 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. In the supporting acute oral and dermal toxicity studies using the test substance, in rats as well as in rabbit, an LD50 of >5000 mg/kg bw was determined.

 

Acute oral toxicity, supporting study

In a supporting study, with limited details, rats were orally administered 5000 mg/kg bw of the test substance isoamyl butyrate. An LD50 of >5000 mg/kg bw was identified; therefore, the test substance was not classified under CLP.

 

Acute dermal toxicity, supporting study

In an acute dermal toxicity study in rabbits, it was found that the LD50 (rabbits) value was >5000 mg/kg bw for the test substance isoamyl butyrate. Therefore, the test substance was not classified under CLP.

Justification for classification or non-classification

Based on the available data, the substance does not require classification for acute oral and dermal toxicity, according to Regulation (EC) No 1272/2008, as amended for fifteenth time in Regulation (EU) No 2020/1182.