Bis(1-methylheptyl) adipate

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to a draft version of the current OECD guideline 407 with acceptable restrictions (in the publication the results are not presented in every detail)

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Version / remarks:

(draft proposal 1999)

Deviations:

yes

Remarks:

limited number of organs histologically examined

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Bis(2-ethylhexyl) adipate

EC Number:

203-090-1

EC Name:

Bis(2-ethylhexyl) adipate

Cas Number:

103-23-1

Molecular formula:

C22H42O4

IUPAC Name:

bis(2-ethylhexyl) adipate

Details on test material:

- Name of test material (as cited in study report): di(2-ethylhexyl)adipate
- Analytical purity: 99.8%
- Lot No.: LDJ4348

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan, Inc (Shiga, Japan)
- Age at study initiation: approx. 8 weeks
- Weight at study initiation: 308 - 311 g (males); 197-199 g (females)
- Housing: individually in stainless steel, wire-mesh cages
- Diet: commercial diet (MF, Oriental Yeast Col, Tokyo, Japan); ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 2
- Humidity (%): 55 ± 5
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

- Maximum volume applied: 10 mL/kg bw

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

40 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once before the first treatment and once a week thereafter
- Parameters checked: skin, fur, eyes, mucous membranes, the frequency of urine and faeces and autonomic activity (lacrimation, piloerection, pupil size, respiratory pattern), gait, posture, response to handling, occurrence of clonic or tonic movements, sterotypes (excessive grooming, circling), bizarre behaviour (self-mutilation, walking backwards).

BODY WEIGHT: Yes
- Time schedule for examinations: twice weekly

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Time schedule for examinations: weekly

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 data

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: once before the first treatment and once a week thereafter within the scope of the detailed clinical observation
- Dose groups that were examined: all animals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the treatment period
- Anaesthetic used for blood collection: Yes (ether anaesthesia)
- Animals fasted: No data
- How many animals: all animals
- Parameters examined: red blood cell count, white blood cell count, haemoglobin concentration, haematocrit value, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelet count, reticulocyte count, prothrombin time, activated partial thromboplastin time, and differential leukocyte count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the treatment period
- Animals fasted: No data
- How many animals: all animals
- Parameters examined: glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, alkaline phosphatase, cholinesterase, gamma-glutamyl transpeptidase, total cholesterol, triglyceride, glucose, total protein, albumin, blood urea nitrogen, creatinine, total bilirubin, calcium, inorganic phosphorus, sodium, potassium and chlorine, and albumin-globulin ratio

URINALYSIS: No data (frequency is the only examination mentioned)

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examination: In the 4th week
- Dose groups that were examined: all animals
- Battery of functions tested: a functional observation battery (FOB) that tested sensory reactivity to stimuli of different types (auditory, visual and proprioceptive), grip strength, and motor activity

OTHER:
HORMONE ANALYSIS
- Time schedule for examination: at the end of the test period
- Paramters examined (serum concentration): thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3), testosterone, follicle-stimulating hormone (FSH), luteinising hormone (LH), estradiol
ESTROUS CYCLING
- Estrous cycle of all females from day 22 to the day of sacrifice (examining vaginal smears stained with Giemsa)
SPERMATOLOGY
- Sperm morphology, sperm count, numer of homogenization-resistant sperm

Sacrifice and pathology:

GROSS PATHOLOGY: Yes; males: day 29, females after having been dosed for at least 29 days and sacrificed on day 30 - 34 in the diestrous stage
- Organ weights: testes, epididymides, ventral prostate, dorsolateral prostate, seminal vesicles, ovaries, uterus, adrenals, liver, spleen, kidneys, heart, brain, and thymus; thyroid and pituitary gland after organ fixation
HISTOPATHOLOGY: Yes; prostate, including ventral prostate and dosolateral prostate, seminal vesicles, ovaries, uterus, vagina, mammary gland, brain, thyroid, adrenals, liver, spleen, kidneys, stomach, intestine, pancreas, thymus, parathyroids, and pituitary glands

Statistics:

Body weight, food consumption, haematological data, clincal biochemical data, organ weight, spermatological data (sperm counts), FOB data were analyzed by the Bartlett´s test for homogeneity of variance. When the variance was homogeneous data significance level of 5%, one-way analysis for variance was performed. Following a significant difference in this analysis, the difference between the control group and each of the treatment groups was analyzed by the Dunnett´s test. When the variance were not homogeneous, the Kruskal-Wallis test was used. Following a significant difference in this test, the difference between the control group and each of the treatment groups was analyzed by the nonparametric Dunett´s test. FOB countable data and spermatological data were analyzed using the Kruskal Wallis test. When there was a significant difference in this analysis, the difference between the control group and each of the treatment groups was analyzed by the nonparametric Dunnett´s test.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

one female (200 mg/kg bw/day) died as a result of technical error of dosing

Mortality:

no mortality observed

Description (incidence):

one female (200 mg/kg bw/day) died as a result of technical error of dosing

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

increased kidney weights (male; 200 and 1000 mg/kg bw); increased liver weights (male, 1000 mg/kg bw); increased liver, kindey and adrenal weights (female, 1000 mg/kg bw/day)

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

clear spotty pattern in the kidneys of 2 male rats (1000 mg/kg bw/day)

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

increased eosinophilic bodies and hyaline droplets in the kidneys (male, 1000 mg/kg bw/day); increased ovarian follicle atresia, prolongation of the estrous stage (female, 1000 mg/kg bw/day)

Details on results:

CLINICAL SIGNS AND MORTALITY
One female (200 mg/kg bw/day) died as a result of technical error of dosing 14 days after administration .
There was no evidence of toxicity in any of the groups.

BODY WEIGHT AND WEIGHT GAIN
No abnormal findings.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study)
No abnormal findings.

OPHTHALMOSCOPIC EXAMINATION
No abnormalities were detetcted in any group.

HAEMATOLOGY
No abnormalities were detetcted in any group.

CLINICAL CHEMISTRY
No abnormalities were detetcted in any group.

NEUROBEHAVIOUR
No abnormal findings.

ORGAN WEIGHTS
- 1000 mg/kg bw/day: increased liver weight (m/f), increased kidney weight (m/f), increased adrenal weight (f)
- 200 mg/kg bw/day: increased kidney weight (m)

GROSS PATHOLOGY
- 1000 mg/kg bw/day: clear spotty pattern in the kidney of 2 rats (m)

HISTOPATHOLOGY: NON-NEOPLASTIC
- 1000 mg/kg bw/day: increased eosinophilic bodies (7/10, m) and hyaline droplets (8/10, m) in the kidneys

OTHER:
HORMONE ANALYSIS
No abnormalities were detetcted in any group.
SPERMATOLOGY
No abnormalities were detetcted in any group.
ESTROUS CYCLING
- 1000 mg/kg bw/day: increased ovarian follicle atresia (4/10, f); prolongation of the estrous stage (2/10, f)

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: endocrine mediated effects (ovarian follicle atresia and prolonged estrous cycle) and increased liver weights at 1000 mg/kg bw/day but without histopathological changes

2

Key result

Dose descriptor:

NOEL

Effect level:

40 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: increased kidney weights at 200 mg/kg bw (without histopathological changes)

3

Key result

Dose descriptor:

LOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: increased eosinophilic bodies and hyaline droplets in the kidneys (male, 1000 mg/kg bw/day); increased ovarian follicle atresia, prolongation of the estrous stage (female, 1000 mg/kg bw/day)

Target system / organ toxicity

Key result

Critical effects observed:

no

Any other information on results incl. tables

Table 1. Summary of changes in organ weights

	Dose level (mg/kg bw/day)
	Control		40		200		1000
sex	m	f	m	f	m	f	m	f
Relative organ weight (g/100 mg)
Liver	3.55 ± 0.27	3.6 ± 0.23	3.5 ± 0.18	3.46 ± 0.30	3.78 ± 0.38	3.51 ± 0.20	4.29 ± 0.24**	4.12 ± 0.12**
Kidneys	0.59 ± 0.04	0.61 ± 0.04	0.59 ± 0.04	0.63 ± 0.05	0.66 ± 0.04**	0.63 ± 0.04	0.68 ± 0.05**	0.67 ± 0.04*
Adrenals	11.6 ± 1.5	23.3 ± 2.9	11.9 ± 1.6	23.6 ± 2.2	12.0 ± 1.6	23.2 ± 2.2	11.8 ± 1.7	24.1 ± 3.2*

* Significantly different from control at P < 0.05; ** Significantly different from control at P < 0.01