Hexanoic acid, 2-ethyl-, C16-18-alkyl esters

Endpoint summary

Description of key information

Acute oral toxicity:
according to OECD 401, in compliance with GLP, RL1 (Pittermann, 1991): LD50>2000 mg/kg bw
Acute inhalation toxicity:
according to OECD 436, in compliance with GLP, RL1 (Huygevoort, 2010): LC50>5.7 mg/L air
Acute dermal toxicity:
no data available

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

key study

Study period:

10 Sep 1991 - 24 Sep 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance Cetyl-2-Ethylhexanoate. According to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

other: rat, Bor: WISW (SPF) Cpb

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Winkelmann GmbH, Borchen, Germany
- Age at study initiation: approx. 10 weeks
- Weight at study initiation: mean 174 g (males), 165 g (females)
- Fasting period before study: 16 hours
- Housing: groups of 5 animals in Makrolon Type-3 cages with standard softwood bedding
- Diet: pelleted Altromin Maintenance Diet 1324, Altromin GmbH, Lage, Germany , ad libitum
- Water: tap water , ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 25
- Humidity (%): 45 - 60
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

VEHICLE
- Purity: DAB 9

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: several times on the application day and twice daily thereafter.
- Frequency of weighing: one day before application, on the day of application, on days 2, 7 and 14.
- Necropsy of survivors performed: yes, external examination and thoracal and abdominal cavities.
- Other examinations performed: clinical signs, body weight

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: rats

Mortality:

No deaths occurred.

Clinical signs:

other: No signs of systemic toxicity were observed.

Gross pathology:

No treatment- related findings.

Mean body weights (g):

Day	Male	Female
-1	182	173
day of application	174	165
2 d	192	178
7 d	224	179
14 d	260	190
Body weight gain	78	17

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

The available information comprises adequate, reliable (Klimisch score 2) and consistent studies from a reference substance with similar structure and intrinsic properties. Read-across is justified based on common functional group, breakdown products, and similarities in PC/TOX properties (refer to endpoint discussion for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

03 Jun - 17 Jun 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance 2-ethylhexyl oleate. According to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

adopted in 2009

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

other: Crl:WI (Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Age at study initiation: 9 weeks old
- Weight at study initiation: max. ± 20% of the sex mean
- Housing: Before exposure-Group housing of maximally 5 animals per sex per cage in labeled Makrolon cages (type IV; height 18cm.) containing sterilised sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, UK). After exposure - Group housing as described above, maximally 3 animals per sex per cage.
- Diet: pelleted rodent diet (SM R/M-Z from SSNIFF Spezialdiäteb GmbH, Soest, Germany), ad libitum except during exposure to the test substance.
- Water: tap-water, ad libitum except during exposure to the test substance.
- Acclimation period: 5 days before the start of treatment under laboratory conditions.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3
- Humidity (%): 40-70
- Air changes (per hr): 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: To:

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION

- Exposure apparatus: The design of the exposure chamber is based on the flow past nose-pnly inhalation chamber (Am.Ind.Hyg Assoc.J. 44(12): 923-928, 1983). The chamber consists of animal sections with eight animal ports each. Each animal port has its own atmosphere inlet and exhaust outlet.

- Method of holding animals in test chamber: Animals are placed in restraining tubes, which is then connected to the exposure chamber.

- Source and rate of air: The theoretical air flow was at least 1L/min.

- System of generating aerosols: An aerosol was generated by nebulization of the test substance by means of a nebulizer (type 950,
Hospitak Inc., Lindenhurst, NY, USA). The primary aerosol was diluted with pressurized air before it entered the exposure chamber. The mean total airflow was 16 L/min. From the exposure chamber the test atmosphere was passed through a filter before it was released to the exhaust of the fume hood.

- Method of conditioning air: The direction of the flow of the test atmosphere guarantees a freshly generated atmosphere for each individual animal.

- Temperature, humidity, pressure in air chamber: The temperature of the atmosphere was between 20.0 and 20.7 °C and relative humidity was between 28 and 30%. These conditions were considered appropriate for the relatively short 4 hours exposure duration.


TEST ATMOSPHERE
- Brief description of analytical method used: Samples were drawn through a glass fiber filter (type APFC04700, Millipore, Billerica, MA, USA). The collected amount of test substance in the air sample was measured gravimetrically. Sample volumes were measured by means of a dry gas meter (type G 1.6, Actaris Meterfabriek B.V., Dordrecht, The Netherlands).
- Samples taken from breathing zone: yes


VEHICLE
- The test substance was used as delivered by the sponsor

TEST ATMOSPHERE (if not tabulated)
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The MMAD was 2.5 µm (GSD 2.4) and 2.6 µm (GSD 2.3).

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: Target concentrations were based on the cut off concentration values specified in the UN and EC classification guidelines.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetrically

Duration of exposure:

4 h

Concentrations:

The mean actual concentration was 5.7 ± 0.4 mg/L. The nominal concentration was 15.4 mg/L. The generation efficiency (ratio of actual and nominal concentration) was 37%. Data obtained from the opacity monitor showed that the aerosol was sufficiently stable.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Mortality/Viability: twice daily
Clinical signs: twice on the day of dosing (1 and 3 hours after exposure); daily thereafter until day 15
Body weight: recorded on day1 (pre-exposure), 2, 4, 8 and 15
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights, histopathology
All animals were sacrificed at the end of the observation period by an intraperitoneal injection with Euthasol® (AST Farma BV, Oudewater, The Netherlands).

Statistics:

No statistical analysis was performed (the method used was not intended to calculate a LC50 value).

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.7 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: No mortalities occured. Apart from hunched position observed in all on day2 after exposure, no further signs of adverse toxicity were observed until the end of the 14 day observation period.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 15.4 mg/L air (nominal)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortalities occured during the 14-day observation period.

Clinical signs:

other: Hunched posture was shown by all animals on Day 2 after exposure. No clinical signs were noted during exposure.

Body weight:

Body weight gain in males and females were within the range expected for rats of this strain and age used in this type of study.

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

The available information comprises an adequate and reliable study (Klimisch score 2) from a reference substance with similar structure and intrinsic properties. Read-across is justified based on common functional group, breakdown products, and similarities in PC/TOX properties (refer to endpoint discussion for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Justification for grouping of substances and read-across

No sufficient data are available for the acute toxicity of Hexanoic acid, 2-ethyl, C16-18 alkyl esters (CAS No. 90411-68-0). In order to fulfil the standard information requirements set out in Annex IX in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, 1.5, of Regulation (EC) No 1907/2006, whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Acute Toxicity

CAS	90411-68-0	95912-86-0	59130-69-7	26399-02-0
Chemical name	Hexanoic acid, 2-ethyl, C16-18 alkyl esters	Fatty acids, C8-10, C12-18-alkyl esters	Hexadecyl 2-ethylhexanoate	2-Ethylhexyl oleate
MW	368.6-396.7 g/mol	312.53-424.74 g/mol	368.6 g/mol	394.7 g/mol
Acute toxicity oral	Experimental result: LD50 > 2000 mg/kg bw	Experimental result: LD50 > 5000 mg/kg bw	Experimental result: LD50 > 2000 mg/kg bw	Experimental result: LD50 > 5000 mg/kg bw
Acute toxicity inhalation	RA: CAS 26399-02-0	-	-	LC50 > 5.7 mg/L
Acute toxicity dermal	-	-	-	-

 

The above mentioned substances are considered to be similar on the basis of the structural similarity resulting in similar properties and/or activities. The available endpoint information is used to predict the same endpoints for Hexanoic acid, 2-ethyl, C16-18 alkyl esters (CAS No. 90411-68-0).

A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Discussion

Acute oral toxicity

Hexanoic acid, 2-ethyl-, C16-18 alkyl esters was tested in five NMRI mice, which received a single oral administration of 2000 mg/kg bw followed by an observation period of six days similar to OECD guideline 401 (Dufour, 1997). While slight loss of motor activity in 2/5 animals was observed at the day of treatment, normal increase in body weight and no mortality was noted. Thus, the LD50 was considered to be >2000 mg/kg bw.

Acute oral toxicity is assessed by using data from a reliable acute oral toxicity study performed according to GLP and OECD guideline 401 with the structural analogue Hexadecyl 2-ethylhexanoate (Pittermann, 1991). Five rats per sex and dose received an oral dose of 2000 mg/kg bw substance per gavage. As no mortality and no systemic toxicity was found during the 14-days observation period, the LD50 was set to >2000 mg/kg bw.

In another study withFatty acids, C8-10, C12-18-alkyl estersa LD50 of >5000 mg/kg bw was observed in five female NMRI mice (Dufour, 1991). The single oral application of 5000 mg/kg bw did neither lead to any mortality nor to any overt clinical signs. No effects on body weight were observed.

Acute inhalation toxicity

There are no data available on the acute toxicity ofHexanoic acid, 2-ethyl, C16-18 alkyl esters by inhalation.In order to fulfil the standard information requirements set out in Annex VIII, 8.5.2, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006 read-across from the structurally related analogue substance 2-ethylhexyloleate(CAS 26399-02-0)is conducted.

Toxicity via inhalation of the structural analogue 2-ethylhexyloleate was tested in a study performed according to OECD guideline 436 and GLP (Huygevoort, 2010). Three male and female Crl:WI (Han) rats were nose-only exposed to an aerosol of an analytical concentration of 5.7 mg/L for 4 h. Apart from hunched position observed in all animals on Day 2 after exposure, no further signs of adverse toxicity and no mortality were observed until the end of the 14 day observation period. Thus, the LC50 was determined to be >5.7 mg/L.

Acute dermal toxicity

No data are available for the dermal route.

Conclusion

The available data on the acute toxicity of Hexanoic acid, 2-ethyl, C16-18 alkyl esters indicate a low oral toxicity with a LD50 of >2000 mg/kg bw. This was supported by data from structural analogue substances where low oral and inhalation toxicity was observed, yielding LD50 values of >5000 and >2000 mg/kg bw, and a LC50>5.7 mg/L.In conclusion, the available data on acute toxicity ofHexanoic acid, 2-ethyl, C16-18 alkyl estersand structural analogue substances indicate thatHexanoic acid, 2-ethyl, C16-18 alkyl estersis not acutely toxic.

 

Justification for selection of acute toxicity – oral endpoint
Hazard assessment is conducted by means of read-across from a structural analogue. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substance and overall quality assessment (refer to the endpoint discussion for further details).

Justification for selection of acute toxicity – inhalation endpoint
Hazard assessment is conducted by means of read-across from a structural analogue. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substance and overall quality assessment (refer to the endpoint discussion for further details).

Justification for selection of acute toxicity – dermal endpoint
No study required since data via the oral and inhalation route are available.

Justification for classification or non-classification

The available data on acute toxicity of the test substance do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.