Azelaic acid

Repeated dose toxicity: oral

Administrative data

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.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

Docosanoic acid

EC Number:

204-010-8

EC Name:

Docosanoic acid

Cas Number:

112-85-6

IUPAC Name:

docosanoic acid

Details on test material:

- Name of test material (as cited in study report): Docosanoic acid
- Physical state: white powder
- Analytical purity: 85.9 %
- Lot/batch No.: 60805X
- Impurities (identity and concentrations): C14-C20 fatty acids: 10.9 %, C24 fatty acids: 2.3 %
- Storage condition of test material: at room temperature in the dark

Test animals

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

Administration / exposure

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

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300, 1000 mg/kg bw/d
Basis:
other: nominal conc.

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

Examinations

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

Results and discussion

Results of examinations

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

Effect levels

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

Target system / organ toxicity

Critical effects observed:

not specified