Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester

Endpoint summary

Description of key information

Oral (similar to OECD 407), rat: NOAEL≥1000 mg/kg bw/day (m/f) (RA from source substance Dibutyl adipate (CAS 105-99-7))

Dermal (similar to OECD 411), rat: NOAEL = 2000 mg/kg bw/day (m/f) (RA from source substance Ditridecyl adipate (CAS 16958-92-2))

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 September - 07 November 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Sensory reactivity to stimuli, assessment of grip strength and motor activity assessment was not conducted.

Qualifier:

according to guideline

Guideline:

other: Guidelines for 28-Day Repeat Dose Toxicity Test of Chemicals (Japan)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Sensory reactivity to stimuli, assessment of grip strength and motor activity assessment was not conducted.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Japan, Inc., Yokohama, Japan
- Age at study initiation: 5 weeks
- Weight at study initiation: 131 - 155 g
- Fasting period before study: No
- Diet: MF by Oriental Yeast Co., Ltd., Itabashi-ku, Japan, ad libitum
- Water: filtered and UV-irradiated tap water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 25
- Humidity (%): 40 - 70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

olive oil

Details on oral exposure:

VEHICLE
- Amount of vehicle: 5 mL/kg

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

28 days

Frequency of treatment:

once daily, 7 days/week

Dose / conc.:

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

Dose / conc.:

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

Dose / conc.:

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

No. of animals per sex per dose:

6 (main study)
6 (satellite control and high-dose groups)

Control animals:

yes, concurrent vehicle

Details on study design:

- Post-exposure recovery period in satellite groups: 14 days

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Once a week

BODY WEIGHT: Yes
- Time schedule for examinations: Days 0, 7, 15, 21, 28 during treatment, days 35 and 42 during recovery time

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/animal/day: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Day 29 and 43
- Anaesthetic used for blood collection: Yes (Sodium thiopental)
- Animals fasted: No
- How many animals:
6 (main study)
6 (satellite control and high-dose groups)
- Examined parameters: red blood cell (RBC), hemoglobin, hematocrit, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cells (WBC), platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), differential count of leukocytes (neutrophils, eosinophils, basophils, monocytes, lymphocytes)


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Day 29 and 43
- Animals fasted: No
- How many animals: 6 (main study)
6 (satellite control and high-dose groups)
- Examined parameters: total protein, albumin, albumin/globulin ratio (A/G ratio), blood urea nitrogen (BUN), creatinine, glucose, total cholesterol, triglycerides, alkaline phosphatase (ALP), alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, inorganic phosphor, Ca, Na, K, Cl

URINALYSIS: Yes
- Time schedule for collection of urine: 3 week after commencement of treatment
- Metabolism cages used for collection of urine: No
- Animals fasted: No
- Examined parameters: pH, protein, glucose, ketones, bilirubin, occult blood, urobilinogen

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes, control and high dose group

Statistics:

Barlett's test, Dunett's test, Scheffe's test, Kruskal-Wallis test and chi-square test.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

1000 mg/kg bw/day: Slight salivation was observed frequently in high dose group animals after administration (non-adverse).

Mortality:

mortality observed, treatment-related

Description (incidence):

1000 mg/kg bw/day: Slight salivation was observed frequently in high dose group animals after administration (non-adverse).

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY
During treatment slight salivation was observed in males and females in 1000 mg/kg bw/day. This change disappeared during recovery period.

BODY WEIGHT AND WEIGHT GAIN
Body weight and weight gain was not affected by the treatment.

FOOD CONSUMPTION
Food consumption did not differ between the control and treatment groups.

HAEMATOLOGY
No treatment related effects were observed.

CLINICAL CHEMISTRY
No treatment related effects were observed.

URINALYSIS
No treatment related effects were observed.

ORGAN WEIGHTS
No treatment related effects were observed.

GROSS PATHOLOGY
No treatment related effects were observed.

HISTOPATHOLOGY: NON-NEOPLASTIC
No treatment related effects were observed.

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: salivation (non-adverse)

Key result

Critical effects observed:

no

Reference 2

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: salivation (non-adverse)

Remarks on result:

other: source: CAS 105-99-7

Key result

Critical effects observed:

no

Conclusions:

In a subacute oral toxicity study with the source substance Dibutyl adipate (CAS 105-99-7) in rats, the NOAEL for male and female rats was set at ≥1000 mg/kg bw/day. Only slight salivation was observed in males and females treated with 1000 mg/kg bw/day and this effect disappeared during the 14-day recovery period. As explained in the analogue justification, these results are considered to be valid also for the target substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Study duration:

subacute

Species:

rat

Quality of whole database:

The available information comprises an adequate and reliable study (Klimisch score 2) from an analogue source substance. Read-across is justified based on common functional group(s), common precursors/breakdown products, similarities in PC/ECO/TOX properties (refer to analogue justification for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, in accordance with Annex XI, 1.5, of Regulation (EC) No. 1907/2006.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study report, comparable to OECD guideline study with acceptable restrictions (no data on analytical purity, only 2 dose levels tested, open instead of semi-occlusive testing)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

Version / remarks:

(adopted 1981)

Deviations:

yes

Remarks:

(only two doses tested instead of three, open instead of semi-occlusive application, no ophthalmological examination as recommended by the OECD guideline)

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
- Details on the strain: Rat/crl COBS CD[SD] BR/Charles River, Lakeview, New Jersey
- Source: Charles River, Lakeview, New Jersey
- Age at study initiation: 49 days
- Weight at study initiation: males: 161.9 - 166.8 g; females: 149.2 - 150.5 g
- Housing: individually, in suspended, stainless steel cages, with wire mesh bottoms and fronts
- Diet: Purina Certified Lab Chow #5002 in pellet form; ad libitum
- Water: tap water, delivered by an automatic watering syste; ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 50
- Photoperiod (hrs dark / hrs light): 12 / 12

Type of coverage:

open

Vehicle:

unchanged (no vehicle)

Details on exposure:

TEST SITE
- Area of exposure: on the backs of the animals, beginning at the scapula and continuing laterally and posteriorly
- Type of wrap if used: no wrap. Animals were fitted with cardboard "Elisabethan" collars to minimize ingestion of test material.
- Time intervals for shavings or clipplings: approx. 24 h before the start of dosing, hair was then reclipped as necessary, but at least once per week

REMOVAL OF TEST SUBSTANCE
- Washing: approx. 24 h after the last dose each week, as much residual test substance as practical was wiped off with gauze pads.

TEST MATERIAL
- Constant volume or concentration used: yes

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

24 h, 5 days/week

Dose / conc.:

800 mg/kg bw/day (nominal)

Dose / conc.:

2 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale:
The dose levels were chosen on the basis of data obtained in thirteen-week studies of other petroleum-based oils previously conducted in the testing laboratory and on practical considerations. The high dose was the maximum amount that could routinely be applied to the backs of the rats without some of the material running off.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily
- Parameters: appearance, behaviour, excretory function and discharges

DERMAL IRRITATION: Yes
- Time schedule for examinations: weekly
- Erythema and edema at the site of application were graded using the Draize scales. the skin was also examined and graded for chronic deterioration: flaking, thickening, stiffening, cracking, and sloughing.

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

HAEMATOLOGY: Yes
- Time schedule for collection of blood: weeks 5, 9, 13
- Anaesthetic used for blood collection: Yes (diethyl ether)
- Animals fasted: Yes
- How many animals: all
- Parameters:
- red blood cell (RBC) morphology,
- white blood cell (WBC) differentials,
- hematocrit (HTC), hemoglobin (HGB),
- mean corpuscular volume (MCV),
- mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH),
- WBC count, RBC count, platelet count.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: weeks 5, 9, 13
- Animals fasted: Yes
- How many animals: all
- Parameters:
- glucose,
- alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase,
- total protein, albumin, globulin,
- A/G ratio,
- urea nitrogen, uric nitrogen,
- creatinine,
- total bilirubin,
- sodium, potassium, chloride, phosphorus, calcium,
- cholesterol, triglycerides,
- iron,
- lactate dehydrogenase.

URINALYSIS: Yes
- Time schedule for collection of urine: weeks 5, 9, 13
- Metabolism cages used for collection of urine: No data
- Animals fasted: Yes
- Parameters:
- pH,
- specific gravity,
- blood,
- protein,
- bilirubin, urobilinogen,
- glucose,
- ketones.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
All animals were subjected to gross necropsy after sacrifice or spontaneous death.

The following tissues were removed and preserved in 10% neutral buffered formalin:
- adrenals,
- bone with marrow (sternum, rib),
- brain,
- epididymides,
- oesophagus,
- eyes and optic nerves,
- Harderian glands,
- head (entire),
- heart and aorta,
- large intestine (cecum, colon, and rectum); small intestine (duodenum, jejunum, and ileum),
- kidneys,
- lacrimal glands,
- liver (part of median and right lateral lobes),
- lungs and bronchi,
- lymph nodes (cervical, mesenteric, draining if abnormal),
- mammary gland (with skin),
- ovaries,
- pancreas,
- pituitary,
- prostate and seminal vesicles,
- salivary glands (major),
- skeletal muscle and sciatic nerve,
- treated skin,
- spinal cord (cervical, thoracic),
- spleen,
- stomach (glandular and squamous),
- testes,
- thymus,
- thyroid and parathyroids,
- tongue,
- trachea,
- urinary bladder,
- uterus (cervix, corpus, and horns),
- vagina,
- gross lesions.

The following organs were weighed from all animals at terminal sacrifice:
- adrenals, brain, epididymides, gonads, heart, kidneys, liver, prostate, spleen, thymus, thyroid/parathyroid (weighed after fixation), uterus.

HISTOPATHOLOGY: Yes
The following tissues from the control and high-dose animals were processed for microscopic examination. Sections for examination were stained with hematoxylin and eosin.
- adrenal, bone and marrow (sternum), brain, eye and optic nerve (left), gonad, small intestine (duodenum) and large intestine (colon), kidney, liver (median lobe), lung (left lobe), pancreas, treated skin (2 sections), spleen, stomach, thymus, thyroid, urinary bladder, gross lesions.

SPERM MORPHOLOGY: Yes
- The effect of the test substance on sperm morphology was assessed by examining cauda epididymal sperm from the first five control males and the first five high-dose males sacrificed. After the epididymides were weighed, the right epididymis was fixed for possible histopathologic examination and the left was used for analysis of sperm morphology.

Statistics:

Body weight data were analyzed for normality and homogeneity of variances, and then by analysis of variance and Duncan's Multiple Range Test. Organ weights were evaluated using Analysis of Variance and Student-Newman-Keuls' test (p<0.05).

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

chronic deterioration of the skin manifested as flaking in all treated animals (no dose-response relationship)

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

2000 mg/kg bw/day: slight, but statistically significant reduction in body weight gains in males

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Dose-related decreases of globulin concentrations in females.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Dose-related increases in urinary protein concentrations in males and females.

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Reduction in thymus weight was observed in females in both dose groups, however, when the weights were adjusted for differences in body weight, the differences were not statistically significant.

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Mild hyperplasia of sebaceous glands of both sexes at 2000 mg/kg bw/day.

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No treatment-related deaths occurred during the course of the study.
There were no indications of systemic toxicity during the study.
In general, most clinical signs were local effects from the collars (e.g. lesions around the neck, reddish nasal discharge, chromodacryorrhea) or the ocular bleedings (e.g. corneal opacities).

BODY WEIGHT AND WEIGHT GAIN
The rate of body weight gain by the high-dose males was less than that of the controls during the first half of the study. Although always within 10% of the control means, the differences from controls were statistically significant (p<0.05) from day 36 until the end.
The low-dose males and both groups of females had slight reductions in the rate of body weight gain for the first five weeks of dosing. After day 36 the gains in body weight kept pace with their respective control groups, so that there was little percent change for the remainder of the study. Statistically significant differences from control values (p<0.05) were seen sporadically in all three groups between day 29 and 57, but not thereafter.

SKIN IRRITATION
Chronic deterioration of the skin (CDS), manifested only as flaking, was observed equivalently in the males of the low- and high-dose groups (mean scores 0.0 - 1.0). Very slight erythema was seen in a few high-dose males (mean scores: 0.0 - 0.2), mostly at the beginning of the study.
Both groups of females reacted equivalently to the substance, showing the same amount of CDS as the males (mean scores: 0.0 - 1.3), but slightly more erythema (mean scores: 0.0 - 0.5).
In the first part of the study, scabbing was observed on the backs of most of the animals in both treated groups of both sexes, with the males being more affected. The scabs were usually small and were found mostly on the anterior portion. No dose-effect relationship was apparent in either sex and scabbing was rarely seen later in the study.
The skin of the control rats of both sexes was normal throughout the study.

HAEMATOLOGY
No consistent differences among the groups were found that would suggest that the substance had an effect on any of the hematologic parameters examined.

CLINICAL CHEMISTRY
A number of statistically significant effects were observed during weeks five and nine of the study; however, most of the effects disappeared by week thirteen. Apparent effects shown earlier on six out of eight serum components in males and on four out of seven serum components in females were not observed at the termination of the study. Those serum components showing statistically significant effects of the substance following 13 weeks of treatment were: glucose (-13 to -24%), alkaline phosphatase (+39 to +41%) and inorganic phosphorus (+11%) in males and glucose (-12 to
- 14%), albumin/globulin ratio (-15%), globulin (+10%) and iron (-25 to -39%) in females. A dose-effect relationship at a 95% confidence level was observed only in female serum globulin among all the affected serum components.


URINALYSIS
There were dose-related increases in urinary protein concentrations in the females during weeks 5, 9, and 13, and males during weeks 5 and 9. A slight increase in protein concentration, but not dose-related, was seen in the males at week 13.
There were also slight, dose-related increases in urinary ketone concentrations seen sporadically in both males and females. High values in the controls of both sexes at week 13 and the variability of the effect make interpretation of this finding difficult.
All other changes in urinalysis parameters were infrequent and minor.

SPERM MORPHOLOGY
No differences in sperm head or general sperm morphology were observed between control and high-dose rats.

ORGAN WEIGHTS
LIVER: Relative to body weight, the livers were mildly enlarged (p<0.05) in exposed rats (both sexes at 2000 mg/kg bw/day, only in males at 800 mg/kg bw/day). This change was considered treatment-related with no observable microscopic changes (see below). It is regarded as an adaptive response to the test material.
KIDNEY: The mean absolute kidney weight was mildly large in males and females at 2000 mg/kg bw/day and slightly large in males at 800 mg/kg bw/day by approx. 28, 31.4, and 18.2%, respectively. Relative to body weight the kidneys were larger than controls in both sexes at both dose levels. These differences from control were all statistically significant. It is concluded that the mild enlargement of kidneys in rats at 2000 mg/kg bw/day and slight enlargement in males at 800 mg/kg bw/day was treatment-related, with no treatment-related microscopic changes (see below). This may be an adaptive response.
THYMUS: Compared to controls the mean thymus weight was smaller (p<0.05) in exposed females of both the low and high dose levels, by approx. 19 and 22%, respectively. In males, thymus weights were slightly lower than controls, but not statistically significantly different.
OTHER ORGANS: No treatment-related changes.

GROSS PATHOLOGY
LIVER: No gross lesions were seen at necropsy.
KIDNEY: No treatment-related gross lesions were seen at necropsy.
THYMUS: No abnormalities.
OTHER ORGANS: No treatment-related changes.

HISTOPATHOLOGY: NON-NEOPLASTIC
SKIN: During microscopic examination the treated skin of exposed animals was compared with that of the sham controls. This revealed mild hyperplasia of sebaceous glands of both sexes at 2000 mg/kg bw/day. This change is treatment-related.
OTHER: The adrenals, brain, eyes and optic nerves, femur, gonads, heart, intestine (small and large), lung, pancreas, salivary gland (submaxillary), spleen, sternum, thyroids and urinary bladder did not show any treatment-related microscopic changes.

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: (highest dose tested)

Key result

Critical effects observed:

no

Table 1: Mean body weights (g)

		Dose [mg/kg bw/day]
Sex	Day	800	2000	0.0
Males	1	200.1	204.6	199.1
	8	237.2	238.6	242.8
	15	277.2	279.0	287.3
	22	305.8	303.4	319.0
	29	327.6	326.6	344.6
	36	337.5*	335.8*	358.3
	43	358.4*	352.3*	388.5
	50	379.2	387.4*	394.3
	57	390.1	383.9*	412.6
	64	391.1	391.9*	416.8
	71	409.1	399.2*	435.4
	78	420.3	409.8*	442.8
	85	433.7	424.9*	458.9
	91	441.1	433.4*	468.0
Females	1	164.5	163.8	168.8
	8	177.6	178.7	182.9
	15	185.8	196.3	203.3
	22	198.7	198.5	209.9
	29	207.8*	210.5	220.3
	36	213.0*	214.6*	226.1
	43	221.4	222.1	234.4
	50	228.0*	228.4	240.8
	57	230.8*	231.7*	247.1
	64	232.3	235.8	249.9
	71	239.9	238.5	253.9
	78	242.8	245.8	258.8
	85	244.5	248.5	262.8
	91	247.8	253.0	268.2

* significantly different from control (p<0.05)

Table 2: Selected urinalysis parameters [mg/dL]

 

Sex	Group	Week 5		Week 9		Week 13
		Protein	Ketone	Protein	Ketone	Protein	Ketone
Male	Control	50	2.2	38	1.1	38	4.4
	Low dose	85	1.0	92	0.5	72	5.0
	High dose	122	1.7	100	2.5	76	7.5
Female	Control	10	0.8	31	0.8	28	2.0
	Low dose	34	1.0	41	1.0	18	3.0
	High dose	65	2.0	48	0.5	69	4.5

 

Table 3: Selected clinical chemistry parameters after 13 weeks of treatment [percent deviation from control]

 

Sex	Group	Glucose	Alkaline phosphatase	Inorganic phosphorus	Albumin / globulin ratio	Globulin	Iron
Male	Low dose	-13%*	+39%*	+3%	-	-	-
	High dose	-24%*	+41%*	+11%*	-	-	-
Female	Low dose	-12%*	-	-	-4%	+3%	-25%*
	High dose	-14%*	-	-	-16%*	+10%*	-39%*

* significantly different from control (p<0.05)

 

DISCUSSION

 

The test substance, when applied dermally under open conditions at 800 or 2000 mg/kg bw/day, five days per week for thirteen weeks, caused minor effects in rats of both sexes at both dose levels.

 

Small reductions in body weights of the males and females were seen. The reductions in body weight, except in the high-dose males, were considered to be of minimal toxicological importance because they were of very small magnitudes and inconsistent statistical significance. There was no indication that the test substance was causing a prolonged effect on the body weights of either group of either sex.

According to the author of the study report, the basis for the decreases in weight gain in the high-dose males was not known. As possible causes for the observed decreases in body weight gain, the author offered less-than-efficient use of nutrients, an increased metabolic rate, decreased food consumption, or any combination of these.

 

Skin irritation was never severe. The mild reactions that were observed were considered not to be of toxicologic importance because of the extreme conditions employed in the present study (i.e., the large amount of material applied, the fact that it was not removed on a daily basis).

 

Increased urine protein and ketone concentrations also occurred in both sexes.

 

Gross and histopathological examination revealed mild enlargement of the kidneys in males and females at 2000 mg/kg bw/day and in males at 800 mg/kg bw/day. Microscopically, treatment-related lesions were not found in females and males, treated at 2000 mg/kg bw/day. The liver was mildly enlarged in both sexes at the high dose and in males at the low dose. Microscopic examination did not reveal treatment-related changes in the livers. The kidney and liver enlargement were considered adaptive responses.

In exposed females at both dose levels, statistically significant thymus growth reduction was observed and considered treatment-related. No microscopic abnormalities were observed. Therefore, this effect is not considered adverse.

The skin showed treatment-related mild hyperplasia of sebaceous glands in both sexes from the high dose group.

 

All effects in the low-dose groups were borderline as far as their biological significance is concerned. Their importance resides in the fact that they are part of the dose-response relationship which supports the findings in the high-dose groups.

In general, none of the described effects are considered to be adverse effects, thus, the dermal NOAEL was set at 2000 mg/kg bw/d, which was the highest dose level tested.

Reference 2

Endpoint:

sub-chronic toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: (highest dose tested)

Remarks on result:

other: source: CAS 16958-92-2

Key result

Critical effects observed:

no

Conclusions:

In a subchronic dermal toxicity study with the source substance Ditridecyl adipate (CAS 16958-92-2) the NOAEL for male and female rats was set at 2000 mg/kg bw/day, which was the highest dose tested. As explained in the analogue justification, these results are considered to be valid also for the target substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

2 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

The available information comprises an adequate and reliable study (Klimisch score 2) from an analogue source substance. Read-across is justified based on common functional group(s), common precursors/breakdown products, similarities in PC/ECO/TOX properties (refer to analogue justification for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, in accordance with Annex XI, 1.5, of Regulation (EC) No. 1907/2006.

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study report, comparable to OECD guideline study with acceptable restrictions (no data on analytical purity, only 2 dose levels tested, open instead of semi-occlusive testing)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 411 (Subchronic Dermal Toxicity: 90-Day Study)

Version / remarks:

(adopted 1981)

Deviations:

yes

Remarks:

(only two doses tested instead of three, open instead of semi-occlusive application, no ophthalmological examination as recommended by the OECD guideline)

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
- Details on the strain: Rat/crl COBS CD[SD] BR/Charles River, Lakeview, New Jersey
- Source: Charles River, Lakeview, New Jersey
- Age at study initiation: 49 days
- Weight at study initiation: males: 161.9 - 166.8 g; females: 149.2 - 150.5 g
- Housing: individually, in suspended, stainless steel cages, with wire mesh bottoms and fronts
- Diet: Purina Certified Lab Chow #5002 in pellet form; ad libitum
- Water: tap water, delivered by an automatic watering syste; ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 50
- Photoperiod (hrs dark / hrs light): 12 / 12

Type of coverage:

open

Vehicle:

unchanged (no vehicle)

Details on exposure:

TEST SITE
- Area of exposure: on the backs of the animals, beginning at the scapula and continuing laterally and posteriorly
- Type of wrap if used: no wrap. Animals were fitted with cardboard "Elisabethan" collars to minimize ingestion of test material.
- Time intervals for shavings or clipplings: approx. 24 h before the start of dosing, hair was then reclipped as necessary, but at least once per week

REMOVAL OF TEST SUBSTANCE
- Washing: approx. 24 h after the last dose each week, as much residual test substance as practical was wiped off with gauze pads.

TEST MATERIAL
- Constant volume or concentration used: yes

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

24 h, 5 days/week

Dose / conc.:

800 mg/kg bw/day (nominal)

Dose / conc.:

2 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale:
The dose levels were chosen on the basis of data obtained in thirteen-week studies of other petroleum-based oils previously conducted in the testing laboratory and on practical considerations. The high dose was the maximum amount that could routinely be applied to the backs of the rats without some of the material running off.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily
- Parameters: appearance, behaviour, excretory function and discharges

DERMAL IRRITATION: Yes
- Time schedule for examinations: weekly
- Erythema and edema at the site of application were graded using the Draize scales. the skin was also examined and graded for chronic deterioration: flaking, thickening, stiffening, cracking, and sloughing.

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

HAEMATOLOGY: Yes
- Time schedule for collection of blood: weeks 5, 9, 13
- Anaesthetic used for blood collection: Yes (diethyl ether)
- Animals fasted: Yes
- How many animals: all
- Parameters:
- red blood cell (RBC) morphology,
- white blood cell (WBC) differentials,
- hematocrit (HTC), hemoglobin (HGB),
- mean corpuscular volume (MCV),
- mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH),
- WBC count, RBC count, platelet count.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: weeks 5, 9, 13
- Animals fasted: Yes
- How many animals: all
- Parameters:
- glucose,
- alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase,
- total protein, albumin, globulin,
- A/G ratio,
- urea nitrogen, uric nitrogen,
- creatinine,
- total bilirubin,
- sodium, potassium, chloride, phosphorus, calcium,
- cholesterol, triglycerides,
- iron,
- lactate dehydrogenase.

URINALYSIS: Yes
- Time schedule for collection of urine: weeks 5, 9, 13
- Metabolism cages used for collection of urine: No data
- Animals fasted: Yes
- Parameters:
- pH,
- specific gravity,
- blood,
- protein,
- bilirubin, urobilinogen,
- glucose,
- ketones.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
All animals were subjected to gross necropsy after sacrifice or spontaneous death.

The following tissues were removed and preserved in 10% neutral buffered formalin:
- adrenals,
- bone with marrow (sternum, rib),
- brain,
- epididymides,
- oesophagus,
- eyes and optic nerves,
- Harderian glands,
- head (entire),
- heart and aorta,
- large intestine (cecum, colon, and rectum); small intestine (duodenum, jejunum, and ileum),
- kidneys,
- lacrimal glands,
- liver (part of median and right lateral lobes),
- lungs and bronchi,
- lymph nodes (cervical, mesenteric, draining if abnormal),
- mammary gland (with skin),
- ovaries,
- pancreas,
- pituitary,
- prostate and seminal vesicles,
- salivary glands (major),
- skeletal muscle and sciatic nerve,
- treated skin,
- spinal cord (cervical, thoracic),
- spleen,
- stomach (glandular and squamous),
- testes,
- thymus,
- thyroid and parathyroids,
- tongue,
- trachea,
- urinary bladder,
- uterus (cervix, corpus, and horns),
- vagina,
- gross lesions.

The following organs were weighed from all animals at terminal sacrifice:
- adrenals, brain, epididymides, gonads, heart, kidneys, liver, prostate, spleen, thymus, thyroid/parathyroid (weighed after fixation), uterus.

HISTOPATHOLOGY: Yes
The following tissues from the control and high-dose animals were processed for microscopic examination. Sections for examination were stained with hematoxylin and eosin.
- adrenal, bone and marrow (sternum), brain, eye and optic nerve (left), gonad, small intestine (duodenum) and large intestine (colon), kidney, liver (median lobe), lung (left lobe), pancreas, treated skin (2 sections), spleen, stomach, thymus, thyroid, urinary bladder, gross lesions.

SPERM MORPHOLOGY: Yes
- The effect of the test substance on sperm morphology was assessed by examining cauda epididymal sperm from the first five control males and the first five high-dose males sacrificed. After the epididymides were weighed, the right epididymis was fixed for possible histopathologic examination and the left was used for analysis of sperm morphology.

Statistics:

Body weight data were analyzed for normality and homogeneity of variances, and then by analysis of variance and Duncan's Multiple Range Test. Organ weights were evaluated using Analysis of Variance and Student-Newman-Keuls' test (p<0.05).

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

chronic deterioration of the skin manifested as flaking in all treated animals (no dose-response relationship)

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

2000 mg/kg bw/day: slight, but statistically significant reduction in body weight gains in males

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Dose-related decreases of globulin concentrations in females.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Dose-related increases in urinary protein concentrations in males and females.

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Reduction in thymus weight was observed in females in both dose groups, however, when the weights were adjusted for differences in body weight, the differences were not statistically significant.

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Mild hyperplasia of sebaceous glands of both sexes at 2000 mg/kg bw/day.

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY
No treatment-related deaths occurred during the course of the study.
There were no indications of systemic toxicity during the study.
In general, most clinical signs were local effects from the collars (e.g. lesions around the neck, reddish nasal discharge, chromodacryorrhea) or the ocular bleedings (e.g. corneal opacities).

BODY WEIGHT AND WEIGHT GAIN
The rate of body weight gain by the high-dose males was less than that of the controls during the first half of the study. Although always within 10% of the control means, the differences from controls were statistically significant (p<0.05) from day 36 until the end.
The low-dose males and both groups of females had slight reductions in the rate of body weight gain for the first five weeks of dosing. After day 36 the gains in body weight kept pace with their respective control groups, so that there was little percent change for the remainder of the study. Statistically significant differences from control values (p<0.05) were seen sporadically in all three groups between day 29 and 57, but not thereafter.

SKIN IRRITATION
Chronic deterioration of the skin (CDS), manifested only as flaking, was observed equivalently in the males of the low- and high-dose groups (mean scores 0.0 - 1.0). Very slight erythema was seen in a few high-dose males (mean scores: 0.0 - 0.2), mostly at the beginning of the study.
Both groups of females reacted equivalently to the substance, showing the same amount of CDS as the males (mean scores: 0.0 - 1.3), but slightly more erythema (mean scores: 0.0 - 0.5).
In the first part of the study, scabbing was observed on the backs of most of the animals in both treated groups of both sexes, with the males being more affected. The scabs were usually small and were found mostly on the anterior portion. No dose-effect relationship was apparent in either sex and scabbing was rarely seen later in the study.
The skin of the control rats of both sexes was normal throughout the study.

HAEMATOLOGY
No consistent differences among the groups were found that would suggest that the substance had an effect on any of the hematologic parameters examined.

CLINICAL CHEMISTRY
A number of statistically significant effects were observed during weeks five and nine of the study; however, most of the effects disappeared by week thirteen. Apparent effects shown earlier on six out of eight serum components in males and on four out of seven serum components in females were not observed at the termination of the study. Those serum components showing statistically significant effects of the substance following 13 weeks of treatment were: glucose (-13 to -24%), alkaline phosphatase (+39 to +41%) and inorganic phosphorus (+11%) in males and glucose (-12 to
- 14%), albumin/globulin ratio (-15%), globulin (+10%) and iron (-25 to -39%) in females. A dose-effect relationship at a 95% confidence level was observed only in female serum globulin among all the affected serum components.


URINALYSIS
There were dose-related increases in urinary protein concentrations in the females during weeks 5, 9, and 13, and males during weeks 5 and 9. A slight increase in protein concentration, but not dose-related, was seen in the males at week 13.
There were also slight, dose-related increases in urinary ketone concentrations seen sporadically in both males and females. High values in the controls of both sexes at week 13 and the variability of the effect make interpretation of this finding difficult.
All other changes in urinalysis parameters were infrequent and minor.

SPERM MORPHOLOGY
No differences in sperm head or general sperm morphology were observed between control and high-dose rats.

ORGAN WEIGHTS
LIVER: Relative to body weight, the livers were mildly enlarged (p<0.05) in exposed rats (both sexes at 2000 mg/kg bw/day, only in males at 800 mg/kg bw/day). This change was considered treatment-related with no observable microscopic changes (see below). It is regarded as an adaptive response to the test material.
KIDNEY: The mean absolute kidney weight was mildly large in males and females at 2000 mg/kg bw/day and slightly large in males at 800 mg/kg bw/day by approx. 28, 31.4, and 18.2%, respectively. Relative to body weight the kidneys were larger than controls in both sexes at both dose levels. These differences from control were all statistically significant. It is concluded that the mild enlargement of kidneys in rats at 2000 mg/kg bw/day and slight enlargement in males at 800 mg/kg bw/day was treatment-related, with no treatment-related microscopic changes (see below). This may be an adaptive response.
THYMUS: Compared to controls the mean thymus weight was smaller (p<0.05) in exposed females of both the low and high dose levels, by approx. 19 and 22%, respectively. In males, thymus weights were slightly lower than controls, but not statistically significantly different.
OTHER ORGANS: No treatment-related changes.

GROSS PATHOLOGY
LIVER: No gross lesions were seen at necropsy.
KIDNEY: No treatment-related gross lesions were seen at necropsy.
THYMUS: No abnormalities.
OTHER ORGANS: No treatment-related changes.

HISTOPATHOLOGY: NON-NEOPLASTIC
SKIN: During microscopic examination the treated skin of exposed animals was compared with that of the sham controls. This revealed mild hyperplasia of sebaceous glands of both sexes at 2000 mg/kg bw/day. This change is treatment-related.
OTHER: The adrenals, brain, eyes and optic nerves, femur, gonads, heart, intestine (small and large), lung, pancreas, salivary gland (submaxillary), spleen, sternum, thyroids and urinary bladder did not show any treatment-related microscopic changes.

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: (highest dose tested)

Key result

Critical effects observed:

no

Table 1: Mean body weights (g)

		Dose [mg/kg bw/day]
Sex	Day	800	2000	0.0
Males	1	200.1	204.6	199.1
	8	237.2	238.6	242.8
	15	277.2	279.0	287.3
	22	305.8	303.4	319.0
	29	327.6	326.6	344.6
	36	337.5*	335.8*	358.3
	43	358.4*	352.3*	388.5
	50	379.2	387.4*	394.3
	57	390.1	383.9*	412.6
	64	391.1	391.9*	416.8
	71	409.1	399.2*	435.4
	78	420.3	409.8*	442.8
	85	433.7	424.9*	458.9
	91	441.1	433.4*	468.0
Females	1	164.5	163.8	168.8
	8	177.6	178.7	182.9
	15	185.8	196.3	203.3
	22	198.7	198.5	209.9
	29	207.8*	210.5	220.3
	36	213.0*	214.6*	226.1
	43	221.4	222.1	234.4
	50	228.0*	228.4	240.8
	57	230.8*	231.7*	247.1
	64	232.3	235.8	249.9
	71	239.9	238.5	253.9
	78	242.8	245.8	258.8
	85	244.5	248.5	262.8
	91	247.8	253.0	268.2

* significantly different from control (p<0.05)

Table 2: Selected urinalysis parameters [mg/dL]

 

Sex	Group	Week 5		Week 9		Week 13
		Protein	Ketone	Protein	Ketone	Protein	Ketone
Male	Control	50	2.2	38	1.1	38	4.4
	Low dose	85	1.0	92	0.5	72	5.0
	High dose	122	1.7	100	2.5	76	7.5
Female	Control	10	0.8	31	0.8	28	2.0
	Low dose	34	1.0	41	1.0	18	3.0
	High dose	65	2.0	48	0.5	69	4.5

 

Table 3: Selected clinical chemistry parameters after 13 weeks of treatment [percent deviation from control]

 

Sex	Group	Glucose	Alkaline phosphatase	Inorganic phosphorus	Albumin / globulin ratio	Globulin	Iron
Male	Low dose	-13%*	+39%*	+3%	-	-	-
	High dose	-24%*	+41%*	+11%*	-	-	-
Female	Low dose	-12%*	-	-	-4%	+3%	-25%*
	High dose	-14%*	-	-	-16%*	+10%*	-39%*

* significantly different from control (p<0.05)

 

DISCUSSION

 

The test substance, when applied dermally under open conditions at 800 or 2000 mg/kg bw/day, five days per week for thirteen weeks, caused minor effects in rats of both sexes at both dose levels.

 

Small reductions in body weights of the males and females were seen. The reductions in body weight, except in the high-dose males, were considered to be of minimal toxicological importance because they were of very small magnitudes and inconsistent statistical significance. There was no indication that the test substance was causing a prolonged effect on the body weights of either group of either sex.

According to the author of the study report, the basis for the decreases in weight gain in the high-dose males was not known. As possible causes for the observed decreases in body weight gain, the author offered less-than-efficient use of nutrients, an increased metabolic rate, decreased food consumption, or any combination of these.

 

Skin irritation was never severe. The mild reactions that were observed were considered not to be of toxicologic importance because of the extreme conditions employed in the present study (i.e., the large amount of material applied, the fact that it was not removed on a daily basis).

 

Increased urine protein and ketone concentrations also occurred in both sexes.

 

Gross and histopathological examination revealed mild enlargement of the kidneys in males and females at 2000 mg/kg bw/day and in males at 800 mg/kg bw/day. Microscopically, treatment-related lesions were not found in females and males, treated at 2000 mg/kg bw/day. The liver was mildly enlarged in both sexes at the high dose and in males at the low dose. Microscopic examination did not reveal treatment-related changes in the livers. The kidney and liver enlargement were considered adaptive responses.

In exposed females at both dose levels, statistically significant thymus growth reduction was observed and considered treatment-related. No microscopic abnormalities were observed. Therefore, this effect is not considered adverse.

The skin showed treatment-related mild hyperplasia of sebaceous glands in both sexes from the high dose group.

 

All effects in the low-dose groups were borderline as far as their biological significance is concerned. Their importance resides in the fact that they are part of the dose-response relationship which supports the findings in the high-dose groups.

In general, none of the described effects are considered to be adverse effects, thus, the dermal NOAEL was set at 2000 mg/kg bw/d, which was the highest dose level tested.

Reference 2

Endpoint:

sub-chronic toxicity: dermal

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOAEL

Effect level:

2 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: (highest dose tested)

Remarks on result:

other: source: CAS 16958-92-2

Key result

Critical effects observed:

no

Conclusions:

In a subchronic dermal toxicity study with the source substance Ditridecyl adipate (CAS 16958-92-2) the NOAEL for male and female rats was set at 2000 mg/kg bw/day, which was the highest dose tested. As explained in the analogue justification, these results are considered to be valid also for the target substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Study duration:

subchronic

Species:

rat

Quality of whole database:

The available information comprises an adequate and reliable study (Klimisch score 2) from an analogue source substance. Read-across is justified based on common functional group(s), common precursors/breakdown products, similarities in PC/ECO/TOX properties (refer to analogue justification for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, in accordance with Annex XI, 1.5, of Regulation (EC) No. 1907/2006.

Additional information

Justification for read-across

There are no experimental data on repeated dose toxicity available for Fatty acids, C18-unsaturated, 1,6 Hexanediol Diester (EC 947-912-3). To fulfil the standard data requirements defined in Regulation (EC) No. 1907/2006, Annex VIII, 8.6, read-across from appropriate substances is conducted in accordance with Regulation (EC) No. 1907/2006, Annex XI.

According to Article 13 (1) of Regulation (EC) No. 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met”. In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across) “to avoid the need to test every substance for every endpoint”.

For each specific endpoint the source substance(s) structurally closest to the target substance is/are chosen for read across, with due regard to the requirements of adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substances are the basis of read-across. A detailed justification for the analogue read- across approach is provided in the technical dossier (see IUCLID Section 13).

As no experimental data are available on repeated dose toxicity for the target substance, read-across of reliable data on the analogue substances Ditridecyl adipate (CAS 16958-92-2) and Dibutyl adipate (CAS 105-99-7) was conducted.

 

Repeated dose toxicity - oral

CAS 105-99-7

The subacute oral toxicity of Dibutyl adipate (CAS 105-99-7) was investigated in a study similar to OECD guideline 407 and in conformity with GLP (MHLW, 1996, key). Dilutions of the test substance in olive oil were administered once daily via oral gavage to groups of 6 Crj: CD(SD) rats per sex at doses of 20, 140 and 1000 mg/kg bw for a period of 28 days. A similar constituted group received the vehicle and acted as a control. In addition, satellite groups of 6 animals per sex, each for the control and high dose group, were used to investigate the reversibility of effects during a 14-day post-exposure recovery period. No substance-related mortalities occurred during the whole study period. Clinical signs involved slight salivation in males and females at 1000 mg/kg bw/day during treatment. However, this effect disappeared during the 14-day recovery period. Food consumption was similar between treated and control animals and no changes in body and organ weights were noted during the study. No treatment-related alterations in parameters of haematology, clinical chemistry and urinalysis were observed. At gross and histopathological examination, no abnormal findings were reported in treated animals of the whole study. Based on the results of this subacute toxicity study, the NOAEL of Dibutyl adipate was considered to be ≥ 1000 mg/kg bw/day.

Repeated dose toxicity - dermal

CAS 16958-92-2

The subchronic dermal toxicity of Bis(tridecyl) adipate (CAS 16958-92-2) was investigated in a 90-day study similar to OECD 411 and in compliance with GLP (Exxon, 1986, key). The undiluted test substance was applied once daily for 5 days/week to the clipped skin of 10 Sprague Dawley rats per sex and group at dose levels of 800 and 2000 mg/kg bw/day under open conditions. A similar constituted group of animals remained untreated and served as controls. During the study, no treatment-related mortalities and no signs of systemic toxicity were observed. In general, most clinical signs involved local effects from the collars (e.g. lesions around the neck, reddish nasal discharge, chromodacryorrhea) or ocular bleedings (e.g. corneal opacities). Chronic deterioration of the skin (CDS), manifested only as flaking, was observed in males and females treated with 800 and 2000 mg/kg bw. Very slight erythema occurred in animals of both sexes at 2000 mg/kg bw/day and mostly at the beginning of the study. During the first part of the study, scabbing was observed on the backs of most animals of both treatment groups, with males being more affected than females. However, no dose-dependent relationship was apparent in either sex and scabbing was rarely seen later in the study. A slight, statistically significant decrease in body weights compared to controls was noted in treated males from Day 36 to the end of the study at 2000 mg/kg bw/day. Urinalysis revealed a dose-dependent increase in protein concentrations in females during Weeks 5, 9, and 13, and males during Weeks 5 and 9. Furthermore, the concentration of urinary ketone was slightly and dose-relatedly increased in both sexes. No toxicologically relevant changes in parameters of haematology were observed at any sampling interval. At study termination, a dose-dependent (correlation at a 95% confidence level) and statistically significant increase in clinical chemistry parameters was only seen in serum globulin concentration in females. Relative to body weight, the livers were mildly enlarged (p<0.05) in exposed rats of both sexes at 2000 mg/kg bw/day and in males at 800 mg/kg bw/day. The mean absolute kidney weight was slightly increased in males and females at 2000 mg/kg bw/day and in males at 800 mg/kg bw/day. A statistically significant increase in relative kidney weights was observed in both sexes and at both dose levels. In treated females, relative thymus weights were significantly decreased, whereas the decrease in relative thymus weight was not significant in males. Since no concomitant changes in histopathology were observed in liver, kidney and thymus, the effects on organ weights in the animals were considered to be non-adverse and adaptive responses (kidney, liver) to treatment with the test substance. Microscopic examination revealed mild hyperplasia of sebaceous glands of both sexes at 2000 mg/kg bw/day. No further treatment-related lesions were observed at gross and histopathological examination. The percutaneous absorption of the substance in the treated rats was determined to be 9.1 - 10.8% (Exxon, 1986, key), showing no differences between male and female rats.

Based on the results of this study, the systemic NOAEL for subchronic dermal toxicity in Bis(tridecyl) adipate was considered to be 2000 mg/kg bw/day.

In conclusion, no human hazard for systemic toxicity after repeated oral or dermal exposure was identified for the source substancesDibutyl adipate (CAS 105-99-7) and Ditridecyl adipate (CAS 16958-92-2). Thus, Fatty acids, C18 -unsaturated, 1,6 Hexanediol Diester (EC 947-912-3) is not considered as hazardous after repeated oral and dermal exposure.

Justification for classification or non-classification

Based on the analogue read-across approach, the available data on repeated oral and dermal toxicity do not meet the classification criteria according to Regulation (EC) No. 1272/2008, and are therefore conclusive but not sufficient for classification.