Fatty acids, C16-18

Endpoint summary

Description of key information

Reliable studies on oral repeated dose toxicity are available for the following category members:

Subchronic: NOAEL oral = ca. 5000 mg/kg bw/d; CAS# 143-07-7, C12 (Fitzhugh 1960)

Subchronic: NOAEL oral = 1000 mg/kg bw/d; CAS# 112-85-6, C22 (Nagao 2002)

No data are available for repeated dose toxicity after dermal exposure and inhalation, respectively.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study, tested with the source substance CAS 112-85-6. In accordance 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.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Hino, Tokyo
- Age at study initiation: 8 weeks
- Weight at study initiation: male: 312.1 - 363.7 g; female: 205.3 - 230.8 g
- Housing: metal wire floor cages
- Diet (ad libitum): CE-2, CLEA Japan
- Water (ad libitum): tap water
- Acclimation period: 7 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24 ± 1
- Humidity (%): 50 - 65
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
prepared more frequently than once a week; aliquots were kept by each concentration refrigerated in airtight conditions

VEHICLE
- Justification for use and choice of vehicle (if other than water): due to insolubility in water
- Amount of vehicle (if gavage): 5 mL/kg bw
- Lot/batch no. (if required): V6H2050

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

- males: 42 days
- females: from 14 days prior to mating to day 3 of lactation

Frequency of treatment:

once daily

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

300 mg/kg bw/day (nominal)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

13 in each group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on preliminary result in a 14 day-repeated dose toxicity study, where no signs of toxicity were found

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once a day

BODY WEIGHT: Yes
- Time schedule for examinations: males: days 1, 8, 15, 22, 29, 36, 42; pregnancy females: premating days 1, 8, 15; pregnancy days: 0, 7, 14, 20; lactation days: 0, 4; non pregnancy females: day 1, 8, 15, 22, 25

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION: No data

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes (males only)
- Time schedule for collection of blood: prior to autopsy
- Anaesthetic used for blood collection: Yes (identity): pentobarbital sodium
- Animals fasted: 18 - 24 hours before sacrifice
- How many animals: all surviving animals
- Parameters checked: red blood cell count (RBC), white blood cell count (WBC), haemoglobin content (Hb), mean corpuscular volume (MCV), haematocrit (Ht), mean corpuscular haemoglobin content (MCH), mean corpuscular haemoglobin concentration (MCHC)

CLINICAL CHEMISTRY: Yes (males only)
- Animals fasted: 18 - 24 hours before sacrifice
- How many animals: all surviving animals
- Parameters checked: total protein, albumin, total cholesterol concentration, glucose, urea nitrogen, creatinine, alkaline phosphatase activity, GOT, GPT, γ-GTP, triglyceride concentration, inorganic phosphorus, total bilirubin, calcium, sodium, potassium, chlorine, A/G ratio

URINALYSIS: No

Sacrifice and pathology:

Organ weights:
male: heart, liver, kidneys, thymus, testes, epididymides
female: heart, liver, kidneys, thymus

Pathological findings and Histopathology (control and 1000 mg/kg bw group):
male: heart, liver, spleen, kidney, adrenal, testis, epididymis, brain, thymus, bladder
female: brain, liver, spleen, thymus, kidney, adrenal, bladder, heart, ovary

Statistics:

Yates test, Mann-Whitney U test, Fisher exact test, Bartlett test, Dunnett test, Scheffe test, Kruskal-Wallis test

Details on results:

CLINICAL SIGNS AND MORTALITY
- Males: No deaths or abnormalities in general condition were observed in any of the treated groups
- Females: No deaths were observed in any treated group

BODY WEIGHT AND WEIGHT GAIN
- Males: significant increase (p<0.01) compared to control was observed in 100 mg/kg group between 8 - 15 days and between 15 - 29 days. However, since no change was observed in other groups, it was considered not related to the dosing of compound.
- Females: no significant change in body weight was noted

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
- Males: no changes in food consumption related to the dosing of compound
- Females: significant decrease (p<0.01) compared to control was observed during lactation in 100 mg/kg group. However, since no other changes in food consumptio were noted in 300 mg/kg and 1000 mg/kg, it was not related to the dosing with the compound.

HAEMATOLOGY
- Males: a significant decrease (p<0.01) of mean corpuscular haemoglobin concentration (MCHC) compared to control was found in the 300 and 1000 mg/kg bw dose group, respectively. No other differences were noted.

CLINICAL CHEMISTRY
- Males: a significant decreased ALP level (p<0.05) compared to control was found in all dosing groups. A significant decreased glucose level (p<0.05) compared to control was found in the high dose group. While a significant increase in chloride (p<0.05) was found in the 300 mg/kg bw group, a significant decrease in calcium content (p<0.01) and in total protein (p<0.05) was noted in this group. However, all the findings lack a dose-dependency and were regarded as incidental.

ORGAN WEIGHTS
- Males: in 100 mg/kg bw males, the actual weight ratio of liver weight compared to control values were increased (p <0.05) . No other significant differences were found in all groups. Thus, this finding lacks a dose-dependency and was regarded as incidental.
- Females: actual kidney weight was significantly reduced (p<0.05) in the 100 mg/kg bw group. No other weight changes were noted. Thus, this finding lacks a dose-dependency and was regarded as incidental.

GROSS PATHOLOGY
Males:
- Heart: myocardial degeneration was noted in one animal of the control group and the 1000 mg/kg bw group, respectively
- Liver: periportal fatty change of the liver was found in all animals of the control and the high dose group. Focal necrosis was noted in one animal of the high-dose group.
- Spleen: all animals of the control and the high-dose group showed brown pigment deposits of the spleen as well as extramedullary hematopeiosis
- Kidney: while fibrosis was only found in 1/13 animals of the control group, eosinophilic bodies and basophilic tubules in the cortex were noted in animals of both control and 1000 mg/kg groups
- Adrenal gland: one animal of the high-dose group showed fibrosis
- Testis: atrophy of the seminiferous tubules was observed in two animals of the 1000 mg/kg dose group, with one animal affected on both sides and one side affected in the other animal. No other abnormalities were noted.
- Epididymis: abnormal sperm granuloma was found in one animal of the control group
- Brain: no abnormal findings noted
- Thymus: no abnormal findings noted
- Bladder: no abnormal findings noted

Females:
- Brain: one animal of the high-dose group showed abnormal mineral deposition in the thalamus
- Liver: focal necrosis and fibrosis was found in one animal of the control group, while one animal of the high-dose group showed only focal necrosis
- Spleen: brown pigmentation and extramedullary hematopeiosis was found in animals of the control and the high-dose group, but no varying degrees of frequency was observed
- Thymus: atrophy and bleeding was observed in animals of both groups, control and high-dose group, respectively
- Kidney: basophilic tubules of the cortex and a dilatation of the renal pelvis was seen in the control and high-dose group
- Adrenal gland: cortical necrosis was observed in one animal of the control group
- Heart: no abnormal findings noted
- Bladder: no abnormal findings noted

Dose descriptor:

NOAEL

Remarks:

repeated dose toxicity

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse substance -related systemic effects were noted

Critical effects observed:

not specified

Reference 2

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented publication which meets basic scientific principles

Principles of method if other than guideline:

Feeding study, where lauric acid was given at a concentration of 10% in the diet to 5 male rats for 18 weeks

GLP compliance:

no

Limit test:

yes

Species:

rat

Strain:

Osborne-Mendel

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 40 - 50 g
- Housing: individually
- Diet (e.g. ad libitum): basal diet of ground commercial biscuit; ad libitum
- Water (e.g. ad libitum): water; ad libitum

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): every two weeks
- Mixing appropriate amounts with (Type of food): by blending the basal diet of ground commercial biscuit with lauric acid

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

18 weeks

Frequency of treatment:

continuously available by feed

Dose / conc.:

10 other: % (nominal in diet)

Dose / conc.:

5 000 mg/kg bw/day (nominal)

Remarks:

other: in diet; based on the average daily food consumption of 5 g/100g bw (WHO, 1987)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: no data

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: no data

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No


OPHTHALMOSCOPIC EXAMINATION: No


HAEMATOLOGY: Yes
- Time schedule for collection of blood: towards the ed of study period
- Anaesthetic used for blood collection: No data
- Animals fasted:No data
- How many animals: 5


CLINICAL CHEMISTRY: No.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Details on results:

CLINICAL SIGNS AND MORTALITY
No clinical signs and no mortality noted.

BODY WEIGHT AND WEIGHT GAIN
No adverse effects on weight gain noted.

ORGAN WEIGHTS
No significant differences between the controls and test animals noted.

GROSS PATHOLOGY
No significant differences between the controls and test animals noted.

Dose descriptor:

NOAEL

Effect level:

ca. 10 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no substance-related effects were noted

Dose descriptor:

NOAEL

Effect level:

10 other: % in diet

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no substance-related effects were noted

Critical effects observed:

not specified

There were no observable clinical effects, no adverse effects on weight gain, nor was there any mortality.

Gross organ pathology and comparison of individual organ weights showed no significant differences between the controls and test animals.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Additional information

Fatty acids are found in all living organisms fulfilling fundamental physiological functions within the body. Based on this role within the body no toxicity potential of fatty acids after repeated exposure is expected as it could be demonstrated with C12 fatty acid (lauric acid) and with C22 fatty acid (docosanoic acid), respectively.

The repeated dose toxicity of docosanoic acid was evaluated in a combined repeated dose and reproductive/developmental toxicity screening test performed under GLP according to OECD guideline 422 (Nagao et al, 2002). Groups of 13 male and 13 female Sprague-Dawley rats per dose received daily doses of 100, 300 and 1000 mg/kg bw/d of docosanoic acid by gavage. While the males were treated for 42 consecutive days, the females received the test substance from 14 days prior to mating until day 3 of lactation. As a result of this treatment, neither mortality nor abnormalities in general condition were observed. In addition, no changes in body weight, body weight gain and food consumption were found in all dose groups. The observed minor changes in the corpuscular hemoglobin concentration, glucose, chloride, calcium and alkaline phosphate levels were regarded as incidental which also holds true for the observed changes in liver weights in male and kidney weights in females, respectively. All histological findings noted in all dose groups were also detected in the control groups, so that all findings could be regarded as not treatment-related. Overall, no treatment-related adverse effects were apparent, so that the highest administered dose of 1000 mg/kg bw/d is regarded as the NOAEL for docosanoic acid under the experimental conditions of this study.

Repeated dose toxicity of lauric acid was analyzed in a study, where 5 male Osborne-Mendel rats were fed a diet containing 10% lauric acid for 18 weeks (Fitzhugh et al., 1960). As results, no clinical effects, no adverse effects on weight gain nor any mortality was noted. The performed gross organ pathology and did not reveal any significant differences of individual organ weights between the controls and test animals. Thus, the given dosage of 10% lauric acid in the diet is regarded as the NOAEL, which corresponds to ca. 5000 mg/kg bw/d, based on an average daily food consumption of 5 g/100 g bw.

In a third study which is insufficient for assessment due to limited documentation, palmitic acid was administered to rats in the diet for six weeks at a dose of 4600 mg/kg bw/d. According to the authors, palmitic acid caused the hyperlipidemia (i.e. an excess of fats or lipids in the blood). No further information was provided.

Taken together, the study data do not provide any evidence of toxicity after repeated administration of fatty acids which is supported by the physiological function of fatty acids within the body.

Justification for classification or non-classification

According to CLP (1272/2008/EC) classification criteria for repeated dose toxicity, fatty acids do not fulfill the criteria for classification and thus a non-classification is warranted for this endpoint.