Ethyl propionate

Endpoint summary

Description of key information

The test item has a low acute toxicity by the oral and dermal routes. The available inhalation data support a classification of the test substance according to CLP as STOT SE 3 (H335).

In rats, the LD50 value via the oral route is > 5000 mg/kg bw (value derived from read-across compound isoamyl isovalerate). In consideration of the molecular weight of both substances (172.27 and 102.13 g/mol), the corrected LD50 for the Ethyl propionate is > 2964.2 mg/kg.

In rats, the LD50 value via the dermal route is > 2000 mg/kg bw.

In an acute inhalation toxicity study in rats LT50s of 35 and 32 minutes were reported in male and female rats, respectively. Effects observed included laboured breathing, lethargy, ataxia, lacrimation, discharge (nasal, oral) and loss of reflexes. Gross pathology observations included red lungs, gas-filled stomachs and liquid-filled tracheas. The vapor concentration applied (210 mg/l) was ten times higher than the CLP classification threshold for inhalation acute toxic Category 4 of 20 mg/l. Therefore a classification for acute inhalation toxicity is not justified.

The lethal effects found in the animals are nevertheless considered serious enough to apply a classification as STOT SE 3 (H335) according to CLP. It is known that highly soluble esters can hydrolyse fast in aqueous solution. Hydrolysis products of the parent substance are ethanol and propionic acid, with propionic acid having higher potency for local lung effects. The formation of propionic acid is therefore considered causing the observed effects in this study.

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:

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, because 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 the necropsy 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.

Reference 2

Endpoint:

acute toxicity: oral

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 attachment to section 13.

Reason / purpose for cross-reference:

read-across source

Specific details on test material used for the study:

read across target substance

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 isoamylisovalerate was >5000 mg/kg bw in rats. The same LD50 value is assumed for the target substance ethylpropionate. Therefore, using a read across approach, the target substance was not classified according to CLP classification.
In consideration of the molecular weight of both substances (172.27 and 102,13 g/mol), the corrected LD50 for the Ethyl propionate is > 2964.2 mg/kg.

Executive summary:

The acute oral toxicity of the target substance was predicted from the source substance (see read across justification; attachment to section 13). In an acute oral toxicity study the LD50 for the source substance was >5000 mg/kg bw in rats. Therefore, using a read across approach, the target substance was not classified according to CLP classification.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 964.2 mg/kg bw

Quality of whole database:

The key study is reliable without restrictions (guideline study conducted using a read across substance).

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

Study period:

1988

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline available

Principles of method if other than guideline:

Animals were exposed to the vapour for defined periods of time or until death occurred, in order to define LT50 values.

GLP compliance:

not specified

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Rats (200-300 g), using 5 per sex.

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: sealed chamber
- Exposure chamber volume: 120 litres
Sample vapour was employed in closed chamber "near saturation". No temperature is given in the report.

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

6 h

Remarks on duration:

Exposure lasted for 6 hours or until death occurred.

Concentrations:

Assuming a temperature of 25°C and a saturation of 90%, the vapor pressure of the substance is calculated as 55 hPa *0.9 = 49.5 hPa = 5% (v/v). With 102 g/Mol and 24.4 l/Mol a concentration of 210 mg/l is calculated.

No. of animals per sex per dose:

5 per sex (female/male)

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days

Sex:

male

Dose descriptor:

other: LT50

Effect level:

35 other: minutes

Based on:

test mat.

95% CL:

>= 26 - <= 47

Exp. duration:

6 h

Sex:

female

Dose descriptor:

other: LT50

Effect level:

32 other: minutes

Based on:

test mat.

95% CL:

>= 23 - <= 44

Exp. duration:

6 h

Sex:

not specified

Dose descriptor:

other: Only lethal exposure

Effect level:

45 other: minutes

Based on:

test mat.

Exp. duration:

6 h

Mortality:

Not specified.

Clinical signs:

other: Laboured breathing, lethargy, ataxia, lacrimation, discharge (nasal, oral) and loss of reflexes.

Gross pathology:

Red lungs, gas-filled stomachs and liquid-filled tracheas.

Interpretation of results:

study cannot be used for classification

Conclusions:

Based on the results of the acute inhalation toxicity study, LT50s of 35 and 32 minutes were identified in male and female rats, respectively when exposed to near saturated vapor (estimated concentration of 210 mg/l). The available data indicate that a strong irritation of the respiratory tract occurred leading to the lethal effects found in the animals. The test substance will be classified as STOT SE 3 (H335) according to CLP.

Executive summary:

Five male & 5 female Sprague-Dawley rats/dose level were administered the test compound as a near saturated vapour, in a sealed 120 litre chamber containing near saturated vapour for 6 hours or until death occurred. Animals were observed for 14 days. Shorter exposures were also conducted (no additional information provided) in order to calculate the LT50s by using the Thompson method. LT50s of 35 and 32 minutes were identified in male and female rats, respectively. The available data indicate that a strong irritation of the respiratory tract occurred leading to the lethal effects found in the animals. The test substance will be classified as STOT SE 3 (H335) according to CLP.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Quality of whole database:

The key study is reliability 4 (not assignable).

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

Study period:

2016-11-03 to 2017-02-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

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
- Age at study initiation: Males 8 weeks old; Females 9 weeks old
- Weight at study initiation: Males 267.5-283.4g; Females 217.6-231.5g
- Housing: one animal per cage
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: for four days after three days of quarantine (including health examinations)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.1-24.6°C (measured), permissible range 19.0-25.0°C
- Humidity (%): 47.7-61-7% (measured), permissible range 30.0-70.0%
- Air changes (per hr): 10-15 clean, fresh, filtered air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: dorsal surface
- % coverage: 5 cm x 6 cm
- Type of wrap if used: lint, Soft Cloth Tape with Liner and surgical tape

REMOVAL OF TEST SUBSTANCE
- Washing (if done): cotton moistened with tepid water
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2.25 mL/kg bw

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5 animals per sex per dose;

Control animals:

yes

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: clinical signs, body weight,organ weights, histopathology, other: no histopathology, since no gross findings were observed at necropsy.

Statistics:

Statistical analysis was performed using SAS progam V9.3.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

All animals at 2000 mg/kg bw and in the control group survived the duration of the study. There were no effects on the mortality. (see table 1)

Clinical signs:

other: All animals at 2000 mg/kg bw and in the control group showed no abnormalities of clinical signs. (see table 2)

Gross pathology:

No gross findings were observed in any animal at 2000 mg/kg bw.

Table 1: Summary of Mortality

Sex	dose (mg/kg)	No. animals	Days after dosing															mortality
			0	1	2	3	4	5	6	7	8	9	10	11	12	13	14
male	0	5	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/5
	2000	5	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/5
Female	0	5	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/5
	2000	5	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0/5

Table 2: Individual Clinical Signs

Sex	Dose (mg/kg)	No. animals	Clinical sign	Hours (day 0) after dosing
				0.5	1	2	4	6
Male	0	5	NOA	5	5	5	5	5
	2000	5	NOA	5	5	5	5	5
Female	0	5	NOA	5	5	5	5	5
	2000	5	NOA	5	5	5	5	5

Sex	Dose (mg/kg)	No. animals	Clinical sign	Days after
				1	2	3	4	5	6	7	8	9	10	11	12	13	14
Male	0	5	NOA	5	5	5	5	5	5	5	5	5	5	5	5	5	5
	2000	5	NOA	5	5	5	5	5	5	5	5	5	5	5	5	5	5
Female	0	5	NOA	5	5	5	5	5	5	5	5	5	5	5	5	5	5
	2000	5	NOA	5	5	5	5	5	5	5	5	5	5	5	5	5	5

NOA: No observable abnormality

Table 3: Individual Body Weights

Sex	Dose		Days after dosing				Gain
			0	3	7	14	0-14
Male	0	Mean	274.9	288.3	315.7	358.1	83.2
		S.D.	3.2	1.9	6.9	12.8	12.4
		N	5	5	5	5	5
	2000	Mean	276.0	284.1	305.2	344.9	68.9
		S.D.	6.8	10.2	12.1	18.9	14.1
		N	5	5	5	5	5
Female	0	Mean	225.5	228.0	237.2	248.4	22.9
		S.D.	4.9	3.2	7.5	14.0	10.0
		N	5	5	5	5	5
	2000	Mean	226.3	227.6	239.2	254.4	28.2
		S.D.	7.0	2.4	4.4	5.2	8.7
		N	5	5	5	5	5

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the result of the acute dermal study in Sprague-dawley rats, the test substance has an LD50 value greater than 2000 mg/kg bw.

Executive summary:

The purpose of this study was to assess the potential toxicity and the approximate LD50 value of the test substance following a single dermal application to Sprague-Dawley rats.

 

Test groups consisted of one dose group at a dose of 2,000 mg/kg and a control group, and each group consisted of 5 males and 5 females. All animals were monitored for clinical signs and body weight changes after dosing during the 14-day observation period. They were subjected to gross necropsy at the end of the observation period.

 

There were no deaths of animals in the 2,000 mg/kg groups. No test substance-related effects were observed in clinical signs, body weight data or necropsy findings in the 2,000 mg/kg groups.

 

Based on the result of this study, the LD50 value of the test substance was considered to be greater than 2,000 mg/kg in male and female rats under the conditions of this study. Therefore, it was not classified according to CLP.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

The key study is reliable without restrictions (guideline study).

Additional information

In the supporting acute oral study in rats, an LD50 of 10.8 ml/kg bw or 9.6 g/kg bw (male) and 9.8 ml/kg bw or 8.7 g/kg bw (female) was determined. An undefined number of mortalities occurred at least during 24 h after administration. Lethary and prostration and red lungs, gray stomach, white to red intestines and gray to red kidney have been seen in rats.

In a supporting acute dermal toxicity test in rabbits it was found that the LD50 (rabbit) is greater than 5000 mg/kg.

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. The available data indicate that a strong irritation of the respiratory tract occurred leading to the lethal effects found in the animals. The test substance will be classified as STOT SE 3 (H335) according to CLP.