Docosanamide

Endpoint summary

Description of key information

RA-S CAS 112-84-5, OECD 423, rat: LD50 > 2500 mg/kg bw
RA-S CAS 112-84-5, OECD 436, rat: LC50 > 2800 mg/m³ (highest feasible aerosol concentration with respirable MMAD)
RA-S CAS 112-84-5, OECD 402, rat: LD50 > 2000 mg/kg bw

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well-conducted GLP study. COA is not included in the report but has been provided separately. Reliability was changed from "1" to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1996

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Animals were randomly allocated to cages. Females were nulliparous and non-pregnant. After an acclimation period of at least five days, animals were selected at random and assigned a number unique within the study. Animals were housed in groups of three by sex in solid-floor polypropylene cages with wood flakes. Except for the overnight fast immediately before dosing and for approximately three to four hours after dosing, food and tap water were available ad lib. Temperature was controlled to 19-25 °C; relative humidity was controlled to 30-70%. Rate of air exchange was at least fifteen changes per hour. Lighting was controlled to give 12 hours continuous light and 12 hours continuous darkness.

Route of administration:

oral: gavage

Vehicle:

peanut oil

Details on oral exposure:

Test material was freshly prepared as required as a suspenion in arachis oil BP. Animals were dosed once only with a dose volume of 10 ml/kg bw by gavage using a metal cannula attached to a graduated syringe. The individual volume administered to each animal was calculated according to the fasted bodyweight at the time of dosing.

Doses:

2000 mg/kg bw as suspension in peanut oil

No. of animals per sex per dose:

Three

Control animals:

no

Details on study design:

Animals were observed for deaths or overt signs of toxicity 1/2, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days. Individual bodyweights were recorded prior to dosing and seven and fourteen days after treatment. At the end of the observation period, animals were killed by cervical dislocation. All animals were subjected to gross pathological examination.

Preliminary study:

not applicable

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 500 mg/kg bw

Based on:

test mat.

Remarks on result:

other: According to guideline, estimated LD50 is greater than 2500 mg/kg based on no mortality at 2000 mg/kg in either sex.

Mortality:

There were no deaths.

Clinical signs:

other: No signs of systemic toxicity were noted during the study.

Body weight:

other body weight observations

Remarks:

All animals showed expected gains in bodyweight over the study period.

Gross pathology:

No abnormalities were noted at necropsy.

No mortalities or signs of systemic toxicity were observed during the observation period.

Interpretation of results:

other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008

Conclusions:

CLP: not classified

Executive summary:

This study was performed to assess the acute oral toxicity of erucamide following single oral administration to the Sprague-Dawley rat. The test material was administered orally as a suspension in arachis oil BP. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy examination. There were no deaths. There were no signs of toxicity. All animals showed expected gains in bodyweight over the study period. No abnormalities were noted at necropsy. The acute oral median lethal dose (LD50) of the test material in the Sprague-Dawley rat was estimated as being greater than 2500 mg/kg bw. No mortalities were noted in animals treated with 2000 mg/kg bodyweight. The test material does not meet the criteria for classification according to Regulations (EC) No 1272/2008.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 500 mg/kg bw

Quality of whole database:

GLP guideline study with a structurally related substance according to the criteria of Regulation (EC) No 1907/2006. Annex XI, paragraph 1.5. Reliability of study originally Klimisch 1, but reliability was changed to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well-conducted study conducted under GLP with no deviations. Reliability was changed from "1" to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Conditions: Animals were housed in Optimal Hygienic Conditions (OHC) inside a barrier system. Air-conditioned with 10 - 15 air changes per hour, continuously monitored environment with a temperature range of 22 ± 3 °C, a relative humidity range of 30 - 70% and a 12 hour fluorescent light / 12 hour dark cycle. A radio program was played during most of the light period.

Accommodation: Animals were housed in groups of 5 of the same sex in Makrolon® type-IV cages with wire mesh tops and standard softwood bedding ("Lignocel" J. Rettenmaier & Söhne GmbH & Co KG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) including paper enrichment (Enviro-dri from Lillico, Biotechnology, Surrey, UK).

Diet: Animals had ad libitum access to a pelleted standard Harlan Teklad 2914C rat maintenance diet (Provimi Kliba AG, 4303 Kaiseraugst, Switzerland) batch no. 82/09 except during the period when the animals were restrained in exposure tubes. Results of the analyses for contaminants and their limits of acceptability are archived at Harlan Laboratories Ltd.

Water: Community tap water from Füllinsdorf ad libitum in water bottles, except during the period when they were restrained in exposure tubes. Results of representative analyses for contaminants are archived at Harlan Laboratories Ltd.

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

Method of test material administration: Inhalation by nose-only, flow-past exposure.
Rationale for Method: Inhalation is a possible route of human exposure.
Frequency of Administration: Single, 4-hour exposure period. Exposure was interrupted twice for a total of 2 minutes for cleaning; nevertheless, the animals were exposed for a period of 4 hours as those interruptions were accounted for.

Rationale for Aerosol Concentration: The target concentration of 3 mg/L air for 4 hours was the highest feasible aerosol concentration with a respirable MMAD as determined during the technical trials.

Duration of Observation Period: 14 days

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetric determination

Duration of exposure:

4 h

Concentrations:

2.8 mg/l

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

Inhalation exposure was performed using a flow-past, nose-only exposure system. The animals were confined separately in restraint tubes which were positioned radially around the exposure chamber. The exposure system ensured a uniform distribution and provided a constant flow of test material to each exposure tube. The flow of air at each tube was 1.0 L/min, which is sufficient to minimize re-breathing of the test aerosol as it is more than twice the respiratory minute volume of rodents. Before commencement of the exposure of the group, technical trials were conducted (without animals) using the inhalation system foreseen for the study. The technical trials were conducted using established procedures based on GLP, but were not
inspected by the Harlan Laboratories Ltd. Quality Assurance. Technical trial data are retained in the raw data.

Statistics:

None

Preliminary study:

The LC50 of erucamide in this study was estimated to be greater than 2.8 mg/L air (gravimetrically determined mean aerosol concentration) which was the highest feasible aerosol concentration with a respirable MMAD.

Sex:

male/female

Dose descriptor:

LC0

Effect level:

2.8 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: Highest feasible aerosol concentration with a respirable MMAD.

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.8 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: Highest feasible aerosol concentration with a respirable MMAD.

Mortality:

All animals survived the scheduled observation period.

Clinical signs:

other: Ruffled fur was recorded in all animals one hour after the end of exposure. There were no clinical signs from Day 2 onwards.

Body weight:

From Day 1 to Day 2, slight body weight loss was noted in all animals. Thereafter normal body weight development was recorded.

Gross pathology:

There were no macroscopic findings.

Other findings:

None

Temperature, relative humidity and oxygen concentration during exposure were considered to be satisfactory for this type of study. Relative humidity values were low as dry air was used for aerosol generation. The mean gravimetric aerosol concentration determined was 2.8 mg/L air as targeted. The aerosol concentration was stable during the exposure period. The Mass Median Aerodynamic Diameters (MMAD) obtained from three gravimetric measurements of particle size distribution during the exposure were similar (MMAD = 3.02 μm, 3.51 μm and 3.84 μm). This led to the conclusion that the particle size of the generated aerosol was fairly stable during the whole exposure period. The MMADs were within the target range of 1 to 4 μm or at the upper limit (third sample), thus deposition of the particles can be assumed to have occurred in both the upper and the lower respiratory tract. The aerosol concentration was at the technical limit as the third sample was at the upper limit. In addition, the Geometric Standard Deviations (GSD) were within the target range of 1.5 to 3. Hence, the particle size distributions obtained were considered to be appropriate for acute inhalation toxicity testing.

Interpretation of results:

other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/200

Conclusions:

CLP: not classified
In conclusion, the LC50 of (Z)-docos-13-enamide obtained in this study was estimated to be greater than 2.8 mg/L air (gravimetrically determined mean aerosol concentration) which was the highest feasible aerosol concentration with a respirable MMAD.

Executive summary:

A group of three male and three female albino rats [RccHanTM:WIST(SPF)] was exposed by nose-only, flow-past inhalation for four hours to the test item at a gravimetrically determined mean concentration of 2.8 mg/L air. All animals were observed for clinical signs and mortality during the inhalation exposure and the subsequent 14-day observation period. Body weights were recorded prior to exposure on test day 1, and during the observation period on test days 2, 4, 8 and 15 before necropsy. On test day 15 all animals were sacrificed and necropsied. The ranges of aerosol concentration, temperature, relative humidity, oxygen content and airflow rate measured during the exposure were considered to be satisfactory for a study of this type. In addition, the test item was considered to be respirable by rats. All animals survived the scheduled observation period. Ruffled fur was recorded in all animals one hour after the end of exposure. There were no clinical signs from day 2 onwards. There were slight effects on body weight. There were no macroscopic findings. In conclusion, the LC50 of (Z)-docos-13-enamide obtained in this study was estimated to be greater than 2.8 mg/L air (gravimetrically determined mean aerosol concentration) which was the highest feasible aerosol concentration with a respirable MMAD.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

> 2 800 mg/m³ air

Physical form:

inhalation: dust

Quality of whole database:

GLP guideline study with a structurally related substance according to the criteria of Regulation (EC) No 1907/2006. Annex XI, paragraph 1.5. Reliability of study originally Klimisch 1, but reliability was changed to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

migrated 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: Well-conducted study performed under GLP with certificate. Reliability was changed from "1" to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Animals were housed under standard laboratory conditions. Rooms were air-conditioned with 10-15 air changes per hour, and continuously monitored environment with ranges for room temperature of 22 ± 3 °C and for relative humidity between 30-70% (values above 70% during cleaning process were possible), automatically controlled light cycle of 12 hours light and 12 hours dark, music during the daytime light period.

Accommodation: During acclimatization in groups of five per sex in Makrolon type-4 cages with standard softwood bedding. Individually in Makrolon type-3 cages with standard softwood bedding (‘Lignocel’ J. Rettenmaier & Söhne GmbH & Co. KG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) during treatment and observation.

Diet: Pelleted standard Provimi Kliba 3433 rat/mouse maintenance diet, batch no. 58/09 (Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) ad libitum.
Results of respective analyses for contaminants are included in the study report.
Water: Community tap water from Itingen was available ad libitum. Results of bacteriological assay, chemical and contaminant analyses of respective samples are included in the study report.

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

One day before treatment, the backs of the animals were clipped with an electric clipper, exposing an area of approximately 10% of the total body surface. Only those animals without injury or irritation on the skin were used in the test.

On Day 1, the test item was applied at a dose of 2000 mg/kg body weight evenly to a moistened surgical gauze pad (ca. 5 x 5 cm), placed on the exposed site and held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and an elastic adhesive restrainer bandage wrapped around the abdomen. The test item will remain in contact with the skin for 24 hours. Twenty-four hours after the application the dressing was removed and the skin was flushed with lukewarm tap water and dried off with disposable paper towels. Thereafter, the reaction sites
were assessed.

Duration of exposure:

24 hours

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

Five

Control animals:

not required

Statistics:

None

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: limit test

Mortality:

No deaths occurred during the study.

Clinical signs:

other: No clinical signs were evident during the course of the study.

Body weight:

other body weight observations

Remarks:

The body weight of the animals was within the range commonly recorded for this strain and age.

Gross pathology:

No macroscopical changes were evident at necropsy.

Other findings:

Slight desquamation was noted in one male on the observation days 7 and 8.
No dermal changes were seen in the females.

Body Weights

 

Animal	1	2	3	4	5
Day 1	244	247	238	250	240
Day 8	271	281	267	278	270
Day 15	305	317	304	310	305

Interpretation of results:

other: CLP criteria not met, no classification required according to Regulation (EC) No 1272/2008

Conclusions:

CLP: not classified
The acute dermal LD50 of erucamide (112-84-5) in rats is >2000 mg/kg.

Executive summary:

Five male and five female RccHan:WIST (SPF) rats were treated with erucamide at 2000 mg/kg by dermal application. The test item was applied to a gauze patch moistened with water. The application period was 24 hours. The animals were examined daily during the acclimatization period and mortality, viability and clinical signs were recorded. All animals were examined for clinical signs within the first 30 minutes and at approximately 1, 2, 3 and 5 hours after treatment on day 1 and once daily during test days 2-15. Local signs were noted once daily from test day 2 to 15. Mortality/viability was recorded within the first 30 minutes and at approximately 1, 2, 3 and 5 hours after administration on test day 1 (with the clinical signs) and twice daily during days 2 - 15. Body weights were recorded on day 1 (prior to administration) and on days 8 and 15. All animals were necropsied and examined macroscopically. No deaths occurred during the study. No clinical signs were evident during the course of the study. The body weight of the animals was within the range commonly recorded for this strain and age. Slight desquamation was noted on day 7 - 8 of observation in a single male. All other animals were without findings. No macroscopical findings were evident. The median lethal dose of erucamide after single dermal administration to rats of both sexes, observed over a period of 14 days, is: LD50 (rat): greater than 2000 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

> 2 000 mg/kg bw

Quality of whole database:

GLP guideline study with a structurally related substance according to the criteria of Regulation (EC) No 1907/2006. Annex XI, paragraph 1.5. Reliability of study originally Klimisch 1, but reliability was changed to "2" according to the ECHA guidance document "Practical guide 6: How to report read-across and categories".

Additional information

There is no data available on the acute toxicity of docosanamide (CAS 3061-75-4). In order to fulfil the standard information requirements set out in Annex VIII, 8.5, and in accordance with Annex XI, 1.5 of Regulation (EC) No 1907/2006, read-across from a structurally very closely related substance is conducted.

A detailed justification for the analogue approach is provided in the technical dossier (see IUCLID sections 7.1 and 13).

Oral

There are 3 reliable studies available for the structurally related substance (Z)-Docos-13-enamide

(CAS 112-84-5, erucamide), which is the mono-unsaturated fatty amide of the same carbon chain length. Due to this close relationship between source and target substance both molecules share very similar characteristics; therefore, more or less identical toxicokinetics and toxicological potential can be assumed.

The key study was conducted according to OECD 423 (Acute Toxic Class Method). In this study 3 rats per sex were exposed to a limit dose of 2000 mg/kg bw of (Z)-Docos-13-enamide (CAS 112-84-5), followed by a 14-day observation period (Sanders, 2000). Subsequently, the animals were sacrificed and subjected to gross pathological examination. No mortalities or clinical signs were observed in either sex, the animals showed no deviations in body weight gain, and no abnormalities were noted at necropsy. According to the guideline the LD50 was estimated to be greater than 2500 mg/kg bw, based on the lack of mortality at the limit dose in either sex.

The second study was conducted according to EU Method B.1 (Reijnders, 1988). In this study 5 rats per sex were exposed to a limit dose of 5000 mg/kg bw by oral gavage, applied in two doses of 2500 mg/kg bw each within 24 hours in order not to exceed the maximum permissible dose volume of 10 mL/kg bw. In the subsequent 14-day observation period no mortality or clinical signs were observed, and all animals showed normal body weight gain. Gross pathology at termination of the study did not reveal any treatment-related abnormalities, either. Therefore, an LD50 > 5000 mg/kg bw was derived from this study.

In the third available study on acute oral toxicity, performed according to OECD 401, five rats per sex were exposed to a limit dose of 2000 mg/kg bw by oral gavage, followed by a 14-day observation period (Whittaker, 1986). During the study period no mortality and no clinical signs were observed. All animals showed normal body weight gain during the observation period, and no abnormalities were noted at the terminal necropsy. Based on these observations an LD50 > 2000 mg/kg bw was derived from this study.

Inhalation

There is no data available for the acute inhalation toxicity of docosanamide, but a reliable study is available for the structurally related substance (Z)-Docos-13-enamide (CAS 112-84-5, erucamide) conducted according to the Acute Toxic Class Method (OECD 436) (Pothman, 2010). In this study 3 rats per sex were nose-only exposed for a period of 4 hours to a concentration of 2.8 mg/L erucamide in air, which is the maximum technically feasible aerosol concentration with a respirable MMAD. The only effects observed during the 14-day observation period were ruffled fur in all animals 1 hour after the end of exposure and a slight body weight loss from day 1 to day 2. Thereafter normal body weight development was recorded. No mortality occurred, and there were no findings at terminal gross pathology. Therefore, the LC0 was determined to be 2.8 mg/L air under the conditions of the study, and a LC50 > 2.8 mg/L (corresponding to 2800 mg/m³ air) was derived, accordingly.

Dermal

There is no data available for the acute dermal toxicity of docosanamide, but a reliable study is available for the structurally related substance (Z)-Docos-13-enamide (CAS 112-84-5, erucamide) conducted according to OECD 402 (Braun, 2010). Five rats per sex were exposed to a limit dose of 2000 mg/kg bw for 24 hours under semiocclusive dressing, followed by a 14-day observation period. No mortality or clinical signs were observed, and no macroscopical changes were noted at terminal necropsy. Body weights during the study period were within the common ranges for rats of this strain and age. Slight desquamation was observed in one male on days 7 and 8, while no dermal reactions were noted in the females. Based on the results of the study a LD50 >2000 mg/kg bw for acute dermal toxicity was derived.

Based on the available data on acute oral and dermal toxicity of the structural analogue, it may be concluded that docosanamide (CAS 3061-75-4) does not exert acute toxicity via the oral, inhalation and dermal route, either.

Justification for classification or non-classification

The available data on the acute toxicity of (Z)-Docos-13-enamide (CAS 112-84-5, erucamide), which is structurally very closely related to docosanamide (CAS 3061-75-4) according to the criteria of Regulation (EC) No 1907/2006, Annex XI, 1.5, do not meet the criteria for classification according to Regulation (EC) No 1272/2008; therefore, docosanamide (CAS 3061-75-4) is not expected to exert acute toxicity, either, and the data are conclusive but not sufficient for classification.