Registration Dossier

Administrative data

Description of key information

OECD 401, rat: LD50 > 2400 mg/kg bw
OECD 402, rat: LD50 > 2000 mg/kg bw
Waiving - Acute toxicity: inhalation

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study.
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
Deviations:
no
GLP compliance:
yes
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Iffa-Credo, Brussels, Belgium
- Age at study initiation: 9-10 weeks
- Weight at study initiation: males 326-352 g, females 206-238 g
- Fasting period before study: yes, feed was withheld twice; once overnight before first dosing until approximately 3-3.5 hours after administration and a second time 10-11 hours overnight before the second dosing until approximately 4 hours after administration of the test substance. Between the two fasting periods there was a 3-hour feeding period.
- Housing: Individually in polycarbonate cages; Bedding material (purified sawdust, Woody Clean, was recceived from the Broekman Institute, Someren, The Netherlands).
- Diet (e.g. ad libitum): Standard laboratory animal diet (RMH-B, pellet diameter 10 mm), which was obtained from Hope Farms, Woerden, The Netherlands, ad libitum.
- Water (e.g. ad libitum): Tap water, ad libitum.
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-22
- Humidity (%): 50-95
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 160 mg/mL
- Amount of vehicle (if gavage): 7.5 mL
- Justification for choice of vehicle: very low water solubility of test substance

MAXIMUM DOSE VOLUME APPLIED: 2 times 7.5 mL/kg within 24 hours

DOSAGE PREPARATION (if unusual):
The test substance was heated to melting point (approximately 60 °C) and suspended in corn oil (maydis oleum, ACF, Maarssen, The Netherlands). Prior to dosing the suspension was heated to approximately 65 °C and was transferred to a glass syringe; subsequently the syringe was cooled under running cold tap-water and the suspension was administered using a stainless steel cannula.
Doses:
2400 mg/kg bw (twice 1200 mg/kg bw : maximum dose feasible for oral administraion)
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 and weighing: Cage side observations on the day of dosing (approx. once every 2 hours) and daily thereafter. With exception of weekends and holidays a mortality check was performed at the end of the day. Individual body weights (with group means and standard deviation) were measured weekly.
- Necropsy of survivors performed: yes, at the end of the study (Day 14) all surviving animals were sacrificed by CO2-asphyxiation and subjected to autopsy.
- Other examinations performed: clinical signs, body weight
Statistics:
Body weight group means with standard deviations.
Preliminary study:
In order to establish an appropriate dose range six groups of Wistar rats, each comprising 1 male and 1 female, were dosed with an oral dose of the test substance at 2400, 1800, 1000, 560, 320 and 180 mg/kg bw, respectively. No mortalities occurred and no signs of systemic toxicity were observed during the 7-day observation period.
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 400 mg/kg bw
Based on:
test mat.
Sex:
male/female
Dose descriptor:
LD0
Effect level:
2 400 mg/kg bw
Based on:
test mat.
Mortality:
No mortality occurred.
Clinical signs:
No signs of systemic toxicity were observed during the 14-day observation period with exception of Day 1 when lethargy was frequently observed. There was no evident sex-related effect.
Body weight:
Weekly group mean body weight gain was normal. There was no evident sex-related effect.
Gross pathology:
There were no test substance-related gross abnormalitites.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The available information comprises an adequate and reliable study (Klimisch score 1), and is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via inhalation route

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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study.
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Department of Health, UK
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
other: RccHan:WIST
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: at least 200 g, weight variation did not exceed ±20% of the mean for each sex
- Fasting period before study: not required
- Housing: housed individually during the 24-h exposure period and in groups of five, by sex, for the remainder of the study in suspended solid-floor polypropylene cages furnished with woodflakes. Animals were provided with environmental enrichment items considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.
- Diet: 2014C Teklad Global Rodent diet (Harlan Laboratories UK Ltd., Oxon, UK), ad libitum
- Water: mains drinking water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12
Type of coverage:
semiocclusive
Vehicle:
arachis oil
Details on dermal exposure:
TEST SITE
- Area of exposure: clipped back and flanks
- % coverage: approximately 10% of the total body surface area
- Type of wrap if used: a piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage

REMOVAL OF TEST SUBSTANCE
- Washing (if done): treated skin and surrounding hair were wiped with cotton wool moistened with arachis oil BP to remove any residual test item.
- Time after start of exposure: 24 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw
- Constant volume or concentration used: yes
- For solids, paste formed: yes

VEHICLE
- Amount(s) applied (volume or weight with unit): not applicable, only used for moistening of the test substance
Duration of exposure:
24 h
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 and weighing: The animals were observed for deaths or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days. Individual body weights were recorded prior to application on Day 0 and on Days 7 and 14
- Necropsy of survivors performed: yes, all animals
- Other examinations performed: clinical signs, body weight, external examination, opening of the abdominal and thoracic cavities, appearance of macroscopic abnormalities. After removal of the dressings and subsequently once daily for fourteen days the test sites were examined for primary irritation and scored according to the criteria of Draize (1977).
Statistics:
Using the mortality data obtained, an estimate of the acute dermal median lethal dose (LD50) of the test item was made.
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Mortality:
No mortality occurred.
Clinical signs:
No signs of systemic toxicity were observed.
Body weight:
Animals showed expected gains in bodyweight over the study period except for one male which showed bodyweight loss during the first week but expected gain in bodyweight during the second week.
Gross pathology:
No abnormalities were noted at necropsy.
Other findings:
- Other observations: Dermal reactions: very slight erythema was noted at the test sites of 4/5 females (score 1) which abated after 5 days in 3 females and after 8 days in the fourth. There were no signs of dermal irritation noted at the test sites of the remaining animals.

CONCLUSION:

The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2000 mg/kg bw.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Quality of whole database:
The available information comprises an adequate and reliable study (Klimisch score 2), and is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, of Regulation (EC) No 1907/2006.

Additional information

Oral

The acute oral toxicity of (Z)-N-octadec-9-enylhexadecan-1-amide (CAS 16260-09-6) was investigated in a GLP-conform study performed according to OECD 401 (Thouin, 1986). The test substance diluted in corn oil was administered to 5 Wistar rats per sex at a limit dose of 2400 mg/kg bw by oral gavage. During the 14-day observation period, no mortality and no clinical signs were observed, except for lethargy which was frequently observed among the animals on Day 1 after treatment. The weekly body weight gain of the animals was normal during the study, and no substance-related gross abnormalities were noted at necropsy. Based on these observations, the oral LD50 value in male and female rats was > 2400 mg/kg bw.

Inhalation

In accordance with Regulation (EC) 1907/2006, Annex VIII, Section 8.5.2, column 2, testing by the inhalation route is appropriate if exposure of humans via inhalation is likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size. The substance (Z)-N-octadec-9-enylhexadecan-1-amide is a solid with very low vapour pressure (8.3E-05 Pa at 20 °C) and does not contain respirable particles in a significant amount. Thus, exposure of humans via inhalation is unlikely. Therefore, testing for acute toxicity by the inhalation route is not appropriate and should be avoided for reasons of animal welfare. In addition, reliable data is available for the oral and the dermal route.

Dermal

An acute dermal toxicity study with (Z)-N-octadec-9-enylhexadecan-1-amide (CAS 16260-09-6) was performed according to OECD 402 and under conditions of GLP (Bradshaw, 2012). Five RccHan:WIST rats per sex were exposed to the test substance diluted in arachis oil at a limit dose of 2000 mg/kg bw for 24 h under semiocclusive dressing. During the 14-day observation period, no mortality and clinical signs of toxicity were observed, and no gross pathological changes were noted at necropsy. All animals showed the expected body weights during the study, except for one male which showed bodyweight loss during the first week but expected gain in bodyweight during the second week. Very slight erythema was noted at the test sites of 4/5 females (score 1) which abated after 5 days in 3 females and after 8 days in the fourth. There were no signs of dermal irritation noted at the test sites of the remaining animals. Based on the results of this study, a dermal LD50 value > 2000 mg/kg bw was derived for male and female rats.


Justification for selection of acute toxicity – oral endpoint
There is only one study available.

Justification for selection of acute toxicity – dermal endpoint
There is only one study available.

Justification for classification or non-classification

The available data on the acute toxicity of (Z)-N-octadec-9-enylhexadecan-1-amide (CAS 16260-09-6) do not meet the criteria for classification according to Regulation (EC) No 1272/2008 or Directive 67/548/EEC and are therefore conclusive but not sufficient for classification.