Diisodecyl azelate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

one-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

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

Adequacy of study:

weight of evidence

Study period:

10 Aug 1987 - 12 Jan 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study. According 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.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Alpk:APfSD (WIstar-derived)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Barriered SPF area at ICI Central Toxicology Laboratory, Alderley Park, Cheshire, UK.
- Age at study initiation: (P) 3 wks;
- Housing: two female or one male per cage, individually during gestation and lactation
- Diet: Pasteurised CTI diet, Special Diets Services Ltd., Essex, UK, ad libitum
- Water: Filtered tap water, ad libitum
- Acclimation period: 6-7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-21
- Humidity (%): 40-60
- Air changes (per hr): 15-25
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: Treatment of parental animals started on 10 Aug 1987.

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
An appropriate quantity of test compound was added to 1 kg of CTI diet and mixed in a pestle and mortar before being made up into a premix.
The amount of DEHA to be added to the 30 kg diet to obtain the required concentrations were 9.07 g for the 300 ppm group, 54.44 g for the 1800 ppm group and 362.9 g for the 12000 ppm group.

DIET PREPARATION
- Rate of preparation of diet (frequency): Diets were fed for no longer than 21 days after preparation.

Details on mating procedure:

- M/F ratio per cage: 1/2
- Length of cohabitation: 10 days
- Proof of pregnancy: sperm in vaginal smear referred to as day 1 of pregnancy
- After 10 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged (how): individually
In all pairings brother sister mating was avoided.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of the first batches of all dietary levels were taken from the food jars, prior to feeding, for quantitative analysis.
Further samples were taken at regular intervals for full quantitative analysis by Vortex extration and Soxhlet extraction.
Mean concentrations of all diets analysed were within 2% of target concentration for all dose groups.

Duration of treatment / exposure:

(P) Males: 10 weeks before mating.
(P) Females: 10 weeks before mating
After 10 weeks, the animals were mated to produce a single litter (F1A) which were reared to day 36 post partum.
Test diets were fed continuously throughout the study.

Frequency of treatment:

continuously

Remarks:

Doses / Concentrations:
300, 1800 and 12000 ppm
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
304, 1038 and 11840 ppm
Basis:
other: analytical

Remarks:

Doses / Concentrations:
approx. 52, 178 and 2102 mg/kg bw/day for males and 61, 203 and 2399 mg/kg bw/day for females
Basis:
other: The values were calculated by the mean body weights and the mean food consumption with the analytical compound values

No. of animals per sex per dose:

15 males
30 females

Control animals:

yes, plain diet

Details on study design:

- Strain selection rationale: Historical data on the used rat strain were available in the laboratory.
- Dose selection rationale: The dose levels for this study were based on data from the literature (NTP, 1982) and included an anticipated no effect level and a level at which toxic effects of the test substance were expected at some stage during the course of the study.

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly throughout the premating period (10 weeks). Female rats were weighed on days 1, 8, 15 and 22 of pregnancy and at termination.

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: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes
Food consumption for each cage of rats was recorded throughout the premating periods and calculated on a weekly basis, with the exception of several femal cages where a set of residue and top up values were not recorded during the first week of the study.

Oestrous cyclicity (parental animals):

Not measured

Sperm parameters (parental animals):

Not measured

Litter observations:

Litters were examined for dead or moribund pups at least once daily and any such pups were subjected to a gross post mortem examination.
A count of all live and dead pups was made within 24 hours of parturition (day 1) and thereafter at days 5, 11, 22, 29 and 36 post partum. The sexes of the pups were also recorded at these times. Any clinical abnormalities seen in the pups were recorded.
Individual pup bodyweights were recorded within 24 h of birth (day1) and at days 5, 11, 22, 29 and 36 post partum.
The litters were weaned at day 22 post partum.
Since pups were not individually identified, data were recorded by sex and litter.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals after completion of mating.
- Maternal animals: All surviving animals after weaning their litters.

GROSS NECROPSY
- Gross necropsy consisted of full necropsy.

HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues were prepared for microscopic examination:
Cervix, Prostate, Epididymis, Seminal vesicle, Liver, Testis, Mammary Gland, Uterus, Ovary, Abnormal tissues.
The number of implantation sites in each uterine horn was recorded for each mated female.
Liver weights were recorded from F0 animals with exception of those killed intercurrently.

Postmortem examinations (offspring):

SACRIFICE
All surviving pups were killed as soon as possible after day 36 post partum.

GROSS NECROPSY
Any pups up to and including 18 days of age found dead or with behavioural, functional, or morphological abnormalities were examined by free hand dissection; abnormalities were recorded and the pups were discarded. Pups over 18 days of age found either dead or requiring euthanasia were subjected to a post mortem examination.
All clinical abnormal pups and further normal pups received a gross necropsy so that a minimum of 2 pups of each sex were examined from each litter where possible. All remaining normal pups were killed and discarded after clinical examination.

Statistics:

The following parameters were assessed using appropriate statistical tests:
mean bodyweight gain, food consumption and food utilisation during the premating period, female bodyweight gain during pregnancy, parental liver weights and pup (litter) bodyweight gain until day 36 post partum. Male and female fertility indices, mean length of gestation, mean pre-coital interval, mean live born index, mean survival index, mean litter size, total litter weight and whole litter losses.

Reproductive indices:

- The reproductive performance of the parents was assessed from the records of mating and parturition.
- The fertility of the parents was established by the success of each mating (production of a viable litter).
- The length of gestation was measured in days from date of positive smear to date of birth (but only in fertile females fulfilling the criterion above)
- The pre-coital interval, the time in days between the date of pairing and the date of positive vaginal smear, was measured, and mean value per group was estimated from all pairings with a positive smear.

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

marginal reduction in body weight gain in females of the highest dose group during premating phase; reduction in body weight in week 3 and 4 of pregnancy in females at highest dose; slight increase in food consumption in males at highest dose

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

marginal reduction in body weight gain in females of the highest dose group during premating phase; reduction in body weight in week 3 and 4 of pregnancy in females at highest dose; slight increase in food consumption in males at highest dose

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Test substance intake: slightly less efficient food utilisation in males of highest dose group

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
There were no clinical abnormalities which could be attributed to treatment.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Bodyweight gain was marginally reduced for females receiving 12000 ppm DEHA during the premating phase.
At the start of pregnancy, the body weight of the females treated with 12000 ppm DEHA was marginally lower than controls and there was reduced body weight gain in this treatment group throughout pregnancy, the effect being most marked at weeks 3 and 4 (6% lower on day 22 compared to controls). There was no effect on bodyweight or body weight gain in any other treatment group during the premating period and during pregnancy, respectively.
A slight increase in food consumption in males treated with 12000 ppm DEHA was observed at week 6 to 10, the effects being statisticaly significant at weeks 6-9. The food consumption was unaffected for males receiving 1800 ppm and 300 ppm and for females of all dose groups.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS) Food utilisation was slightly less efficient overall for males receiving 12000 ppm.
REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
There was no effect on either male or female fertility, gestation length or pre-coital interval in any dose group which could be attributed to treatment with DEHA.

ORGAN WEIGHTS (PARENTAL ANIMALS)
Absolute liver weights were increased in both males and females receiving 12000 ppm, by approximately 18%.
Relative to the bodyweights these liver weight increases were 18.9% in males and 19.7% in females.
No effects were seen in any other dose group.

GROSS PATHOLOGY (PARENTAL ANIMALS)
There were no gross changes detected in adults which could be attributed to treatment with exception of accentuated lobular pattern in the liver of two rats fed 12000 ppm DEHA.

HISTOPATHOLOGY (PARENTAL ANIMALS)
No microscopic changes were detected in reproductive organs of those animals which failed to breed and were thus supected infertile.

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

>= 2 102 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: see 'Remark'

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

>= 2 399 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: see 'Remark'

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: The nominal dose was 1800 ppm in diet.

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: The nominal dose was 1800 ppm in diet.

Dose descriptor:

LOAEL

Remarks:

systemic

Effect level:

2 102 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: The nominal dose was 12000 ppm in diet. An increase in liver weight was observed in both male and female parents receiving 12000 ppm DEHA.

Dose descriptor:

LOAEL

Remarks:

systemic

Effect level:

2 399 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: The nominal dose was 12000 ppm in diet. An increase in liver weight was observed in both male and female parents receiving 12000 ppm DEHA. Reduction in bodyweight gain during gestation in the 12000 ppm DEHA group compared with controls.

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, treatment-related

Description (incidence and severity):

mean litter size was slightly reduced at highest dose group (statistically not significant)

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

reduction in mean pup weight for male and female offspring in the highest dose group

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

VIABILITY (OFFSPRING)
The incidence of whole litter losses was not attributed to the treatment with DEHA, although there were four whole litter losses. None in the control group, one in the 300 ppm group, two in the 1800 ppm group and one in the 12000 ppm group. The low incidence and no clear dose-relation was considered as non treatment-related effects.
Mean litter size was slightly (without statistically significance) reduced at 12000 ppm throughout the post partum period. The number of live born pups was unaffected by treatment.
The pup survival rate was not different from control group, when the four whole litter losses were excluded from calculation.

CLINICAL SIGNS (OFFSPRING)
The pups were in good clinical condition. The observed clinical signs were of low incidence with no relationship to DEHA-treatment.

BODY WEIGHT (OFFSPRING)
Mean pup weight gain and total litter weight for both male and female offspring receiving 12000 ppm of the test substance were reduced throughout the whole of the post partum phase in days 1 - 36. No effects were observed in any other dose group.

GROSS PATHOLOGY (OFFSPRING)
There were no findings, which could be considered to be treatment-related.

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Mean pup weight gain and total litter weight were reduced at the highest dose. Litter size was slightly reduced throughout the post-partum period at the highes dose.

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Mean pup weight gain and total litter weight were reduced at the highest dose. Litter size was slightly reduced throughout the post-partum period at the highest dose.

Dose descriptor:

LOAEL

Generation:

F1

Effect level:

2 102 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Mean pup weight gain and total litter weight were reduced. Slighly reduction in litter size throughout the post-partum period.

Dose descriptor:

LOAEL

Generation:

F1

Effect level:

2 399 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Mean pup weight gain and total litter weight were reduced. Slighly reduction in litter size throughout the post-partum period.

Reproductive effects observed:

not specified

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

178 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

The available information comprises adequate, reliable (Klimisch score 2) and consistent studies from a reference substance with similar structure and intrinsic properties. Read-across is justified based on structural similarity between the source and target substance.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Toxicity to reproduction

Justification for grouping of substances and read-across

There are only limited data available on the toxicity to reproduction of diisodecyl azelate (CAS 28472-97-1). In order to fulfil the standard information requirements set out in Annex VII and VIII, 8.4, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with 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).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Overview of toxicity to reproduction

CAS	Toxicity to reproduction
28472-97-1 (a)	RA: CAS 103-23-1 RA: CAS 103-24-2
103-24-2 (b)	OECD 422: NOAEL = 300 mg/kg bw/day (female) OECD 422: NOAEL >= 1000 mg/kg bw/day (male)
103-23-1	OECD 415: NOAEL >= 178 mg/kg bw/day (male) OECD 415: NOAEL >= 203 mg/kg bw/day (female)

(a) The substance subject to registration is indicated in bold font.

(b) Reference (read-across) substances are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information is used to predict the same endpoints for diisodecyl azelate (CAS 28472-97-1). A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

 

CAS 103-24-2

One GLP-conform reprotoxicity screening study according to OECD 422 is available, in which male and female Sprague Dawley rats were exposed to Bis(2-ethylhexyl) azelate (CAS 103-24-2) at dose levels of 100, 300 and 1000 mg/kg bw/day (Shirota, 2004). The test substance in corn oil was administered daily to 13 animals per sex and dose via gavage. Males were treated for a period of 42 days starting 14 days prior to mating, whereas females were exposed to the test substance 14 days prior to mating and until Day 3 of lactation. A similar constituted group received the vehicle and acted as control. No changes in testis and epididymis weight as well as histopathology of reproductive organs were observed in males. Effects on reproductive function involved a statistically significantly increased length of the oestrus cycle in females at 1000 mg/kg bw/day, whereas sperm parameters in males were not affected by treatment. The reproductive performance (copulation, fertility, gestation and implantation and delivery index) and offspring viability (birth, live birth, and viability index) were not altered after exposure to the test substance. In the offspring, no treatment-related effects on body weights and no macroscopic abnormalities were observed.

Based on the results of the study, the NOAEL for reproductive toxicity in female Sprague Dawley rats was established at 300 mg/kg bw/day, whereas the NOAEL for male Sprague Dawley rats was set at ≥ 1000 mg/kg bw/day. In offspring (F1), a NOAEL for systemic toxicity of ≥ 1000 mg/kg bw/day was derived.

 

CAS 103-23-1

The toxicity to reproduction of bis(2-ethylhexyl) adipate (CAS 103-23-1) has been investigated in a one-generation reproduction toxicity study similar to OECD 415.

The effect of bis(2-ethylhexyl) adipate on the fertility of Alpk:APfSD (Wistar-derived) rats was investigated in a GLP-conform study similar to OECD guideline 415 (Tinston, 1988). Groups of 15 male and 30 female parental animals were exposed daily to the test substance at dietary concentrations of 300, 1800 or 12000 ppm, corresponding to mean achieved dose levels of 52, 178 and 2102 mg/kg bw/day for males and 61, 203 and 2399 mg/kg bw/day for females, respectively. A similar constituted group of animals received the plain diet and served as controls. After 10 weeks of treatment the animals were mated to produce a single litter (F1), which were reared until Day 36 post partum. Male parents were killed after completion of mating and female parents were killed after weaning their litter. There was no evidence for any clear effect on bodyweight or food consumption during the premating phase of the study apart a marginal reduction in bodyweight gain for female rats in the 12000 ppm test group. This decrease in body weight continued through gestation in the female animals of the highest dose group compared to controls. There were no treatment-related effects on pre-coital interval, length of gestation, or on male and female fertility. Offspring weight gain, total litter weight and litter size in the 12000 ppm test group were reduced compared to controls, but there was no effect on the number of pups born live or on their survival at any dose level of the test substance. An increase in absolute and relative liver weight was observed in both male and female parents receiving dietary levels of 12000 ppm. No treatment-related findings were observed at gross pathology, except for accentuated lobular pattern in the liver of two female rats fed diets containing 12000 ppm of the test substance. No histological changes were noted in the reproductive organs of those males and females which failed to breed and were thus suspected of being infertile. Based on the results of this study the NOAEL for fertility was set at >= 12000 ppm in the diet, which corresponded to mean achieved dose levels of 2102 and 2399 mg/kg bw/day in males and females, respectively. The NOAEL for systemic toxicity for parental animals (P) and offspring (F1) was considered to be at 1800 ppm, equivalent to dose levels of 178 and 203 mg/kg bw/day in males and females, respectively.

In summary, the NOAEL for fertility from the one-generation reproduction toxicity study of bis(2-ethylhexyl) adipate was set at ≥12000 ppm in the diet, which corresponded to mean achieved dose levels of  ≥ 2102 and ≥2399 mg/kg bw/day in males and females, respectively.

 

Conclusion for toxicity to reproduction

An oral reproduction/developmental toxicity screening test is available for bis(2-ethylhexyl) azelate (CAS 103-24-2) with a NOAEL of 300 mg/kg bw/day based on adverse effects on fertility in females (prolonged estrous stage). Similar effects have been observed with bis(2-ethylhexyl) adipate (CAS 103-23-1) in a subacute repeated dose toxicity study according to OECD 407 (dose levels: 40, 200 and 1000 mg/kg bw/day) where findings at histopathology and in vaginal smears examinations revealed increased ovarian follicle atresia and prolongation of the estrous stage in 4/10 and 2/10 females at 1000 mg/kg bw/day, respectively. No substance-related effects were observed on sperm parameters and histopathology of reproductive organs in males (Miyata et al., 2006). In contrast, a one-generation toxicity study with the same substance (bis(2-ethylhexyl) adipate, CAS 103-23-1) did not result in any adverse effects on fertility up to a maximum dietary dose level of 12000 ppm, which corresponded to 2102 and 2399 mg/kg bw/day in males and females, respectively. 

In female rats delayed estrous cycle have been observed in a subacute toxicity study with bis(2-ethylhexyl) adipate and in a reproduction/developmental toxicity screening study with bis(2-ethylhexyl) azelate.

However fertility was no longer impaired in a one-generation study with bis(2-ethylhexyl) adipate, the study with the longest treatment duration. Based on a lack of effect observed in this latter study, the overall NOAEL for reproduction toxicity was ≥ 2102 mg/kg bw/day, indicating no hazard for reproduction toxicity.

Thus the overall NOAEL for reproduction toxicity was ≥ 2102 mg/kg bw/day, indicating no hazard for reproduction toxicity.

Short description of key information:
No hazard for reproductive toxicity was identified for diisodecyl azelate.

Justification for selection of Effect on fertility via oral route:
Hazard assessment is conducted by means of read-across from structural analogues. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substances and overall assessment of quality, duration and dose descriptor level (refer to the endpoint discussion for further details).

Effects on developmental toxicity

Description of key information

No hazard for developmental toxicity was identified for diisodecyl azelate.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Study period:

15 Sep - 16 Oct 1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study. According 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.

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Alpk:APfSD (Wistar derived)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF colony maintained at the Animal Breeding Unit, ICI Pharmaceuticals, Alderley Park, Cheshire, UK.
- Age at study initiation: 12 weeks
- Weight at study initiation: 218-278 g
- Housing: individually in stainless steel cages with absorbent paper over collecting trays.
- Diet (e.g. ad libitum): CTI diet, Special Diets Services Ltd., Essex, UK.
- Water (e.g. ad libitum): yes

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-24
- Humidity (%): 44-70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light):12/12

IN-LIFE DATES: From: 15 Sept - 16 Oct 1987.

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The experimental diets were prepared in 30 kg batches from premixes.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Chemical stability was observed at 300 ppm up to at least 32 days. This interval was in excess of the maximum period of use of the first batch of diet (21 days from preparation). The achieved concentration was within 8% of target and the doses received by the test groups were approximately 28, 170 and 1080 mg/kg bw/day.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: not reported
- Length of cohabitation: overnight
- Proof of pregnancy: sperm in vaginal smear referred to as day 1 of pregnancy

Successfully mated females were delivered to the experimental unit.
A total of 96 mated females was supplied over a two week period.

Duration of treatment / exposure:

days 1-22 of gestation.

Frequency of treatment:

Continuous feeding

Duration of test:

22 days

No. of animals per sex per dose:

24

Control animals:

yes, plain diet

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: on arrival and daily

BODY WEIGHT: Yes
- Time schedule for examinations: daily during days 1-22 of gestation

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 22
- Organs examined: uterus, ovaries, liver, spleen, kidney, stomach, rectum, abdominal cavity, pelvic cavity,

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes, in each ovary.
- Number of implantations: Yes
- Number of early resorptions: Yes (early intra-uterine deaths)
- Number of late resorptions: Yes (late intra-uterine deaths)
- Other: Each foetus was weighed and individually identified within the litter by means of a cardboard tag. After weighing the foetuses were killed with an intra-cardiac injection of pentobarbitone.

Fetal examinations:

- External examinations and cleft palate: Yes, each foetus
- Soft tissue examinations: Yes, all
- Skeletal examinations: Yes, all
- Head examinations: Yes, the head of each foetus was cut along the fronto-parietal suture line and the brain was examined for macroscopic abnormalities.

Statistics:

Analysis of variance, Student's t-test, Fisher's Exact Test

Indices:

- Pre-implantation loss (No. of corpora lutea / No. of implantations)
- Post implantation loss (No. of implantations / No. of live foetuses)

Historical control data:

Yes, data on variants and frequency of occurence in rats of this strain were given.
Defects like bipartite 5th sternebrae, slightly dilated ureters and kinked ureters were seen in historical controls of this strain.

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
At 12000 ppm a small but statistically significant reduction in maternal bodyweight gain was observed.
There was also a small but statistically significant reduction in food consumption at this dose level from days 2-18 inclusive of gestation.
There was no evidence of maternal toxicity at 300 or 1800 ppm.

Key result

Dose descriptor:

NOAEL

Effect level:

ca. 170 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

LOAEL

Effect level:

ca. 1 080 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Key result

Dose descriptor:

NOAEL

Effect level:

>= 1 080 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Key result

Dose descriptor:

NOEL

Effect level:

ca. 28 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Key result

Dose descriptor:

LOEL

Effect level:

ca. 170 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes. Remark: (non-adverse)

Details on embryotoxic / teratogenic effects:
There was no effect at any dose on foetal weight, litter weight, gravid uterus weight, numbers of intra-uterine deaths or numbers of external abnormalities. At 12000 ppm there was a minimal increase of pre-implantation loss with an associated decrease in litter size.
Six major abnormalities (in five foetuses) were seen in the treated groups and eight in the control group (of which seven consisted of multiple minor skull defects in one litter). There was no evidence that the type or distribution of these abnormalities was related to treatment with the test substance.
Overall, minor skeletal defects were increased in a dose-related manner at 1800 and 12000 ppm of the test substance, while skeletal variants (as a percentage of foetuses affected) were increased at the top dose only. These findings indicated slightly poorer ossification at dose levels of 1800 and 12000 ppm, which were considered to be the result of slight fetotoxicity. However, the slightly poorer ossification is not considered as adverse effect.

Key result

Dose descriptor:

NOAEL

Remarks on result:

not measured/tested

Key result

Abnormalities:

not specified

Key result

Developmental effects observed:

not specified

Table 1: Foetal defects and variants - Intergroup comparison of foetal defects and variants

	Dietary conc. of DEHA (ppm)
	0	300	1800	12000
No. of litters examined	24	23	24	23
External and visceral defects
No. of foetuses examined	282	263	278	243
No. of foetuses showing major defects	1	2	0	2
No. of foetuses showing minor defects only	7	8	9	3
Variants
No. of foetuses showing variants	69	69	81	78*
Skeletal defects
No. of foetuses examined	282	263	278	243
No. of foetuses showing major defects	7	0	1	1
No. of foetuses showing minor defects only	70	78	97**	120**
Variants
No. of foetuses showing variants	270	257	268	243**

 

Table 2: Summary of the type and incidence of major defects

	Dietary conc. of DEHA (ppm)
	0	300	1800	12000
External/Visceral
Situs inversus totalis	0	0	0	1
Left adrenal, kidney and ureter absent	1	0	0	0
Cysts attached to liver	0	1	0	0
Small right kidney	0	1	0	0
Umbilical hernia	0	0	0	1
Skeletal
Skull: Multiple minor defects	7	0	0	0
3^rdand 7^thribs (left) not ossified0	0	0	0	1
1^strib (right) partially ossified	0	0	1	0

 There was no evidence that the test substance is teratogenic to the rat at any of the dose levels tested (up to 12000 ppm -approximately 1000 mg/kg/day). Administration of 12000 ppm DEHA resulted in slight maternal toxicity and slight foetotoxicity.

At 1800 ppm, there was no evidence of maternal toxicity although minimal foetotoxicity was observed. A dietary level of 300 ppm DEHA was a clear no-effect level for embryonic development. 

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 080 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The available information comprises adequate, reliable (Klimisch score 2) and consistent studies from a reference substance with similar structure and intrinsic properties. Read-across is justified based on structural similarity between the source and target substance.

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Developmental toxicity/teratogenicity

Justification for grouping of substances and read-across

There are only limited data available on developmental toxicity of diisodecyl azelate (CAS 28472-97-1). In order to fulfil the standard information requirements set out in Annex VII and VIII, 8.4, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with 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).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

Overview of developmental toxicity

CAS	Developmental toxicity
28472-97-1 (a)	RA: CAS 103-23-1
103-23-1 (b)	OECD 414: NOAEL >= 1080 mg/kg bw/day

(a) The substance subject to registration is indicated in bold font.

(b) Reference (read-across) substances are indicated in normal font. Lack of data for a given endpoint is indicated by “--“.

The above mentioned substances are considered to be similar on the basis of the structural similar properties and/or activities. The available endpoint information is used to predict the same endpoints for diisodecyl azelate (CAS 28472-97-1). A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

 

CAS 103-23-1

In a prenatal developmental toxicity study according to OECD guideline 414, the effects of bis(2-ethylhexyl) adipate (CAS 103-23-1) on mated female Alpk:APfSD (Wistar derived) rats were investigated during Days 1 to 22 of gestation (Hodge, 1988). Groups of 24 females received the test substance at dietary concentrations of 300, 1800 and 12000 ppm, which approximately corresponded to dose levels of 28, 170 and 1080 mg/kg bw/day. A further group of 24 mated females received the plain diet and served as controls. On Day 22 of gestation, dams were sacrificed and maternal as well as foetal examinations were performed. Maternal toxicity occurred at 12000 ppm and involved a small, but statistically significant decrease in body weight gain compared to controls. This effect was accompanied by slight, statistically significant reduction in food consumption between Days 2 to 18 of gestation. No treatment-related clinical signs were observed during the study and no adverse findings were noted at macroscopic examination of dams. There was no effect at any dose level on fetal weight, litter weight, gravid uterus weight, numbers of intra-uterine deaths or numbers of external abnormalities. At 12000 ppm, a minimal increase of pre-implantation loss associated with a decrease in litter size was observed. Six major abnormalities (in five fetuses) were seen in the treated groups and eight in the control group (of which seven consisted of multiple minor skull defects in one litter). There was no evidence that the type or distribution of these abnormalities was related to test substance treatment. Overall, minor skeletal defects were increased in a dose-related manner at 1800 and 12000 ppm, while skeletal variants (as a percentage of fetuses affected) were increased at the 12000 ppm only. These findings indicated slightly poorer ossification at dose levels of 1800 and 12000 ppm, which were considered to be the result of slight fetotoxicity. However, the slightly poorer ossification is not considered as adverse effect. There was no evidence at any dose level, that the test substance was teratogenic in rats. 

Based on the results of the study, the NOEL for developmental toxicity in male and female Alpk:APfSD (Wistar derived) rats was established at 300 ppm, which approximately corresponded to 28 mg/kg bw/day. The NOAEL for developmental toxicity in Alpk:APfSD (Wistar derived) rats was ≥ 12000 ppm, which is equivalent to ca. ≥ 1080 mg/kg bw/day. The NOAEL for maternal toxicity in Alpk:APfSD (Wistar derived) rats was 1800 ppm, which is equivalent to ca. 170 mg/kg bw/day.

 

Conclusion for developmental toxicity/teratogenicity

One study investigating the developmental toxicity via the oral route is available for bis(2-ethylhexyl) adipate (CAS 103-23-1). Due to the absence of any adverse effect, the NOAEL for developmental toxicity was set at ≥ 1080 mg/kg bw/day, the maximum dose administered.

Justification for selection of Effect on developmental toxicity: via oral route:
Hazard assessment is conducted by means of read-across from structural analogues. The selected study is the most adequate and reliable study based on the identified similarities in structure and intrinsic properties between source and target substances and overall assessment of quality, duration and dose descriptor level (refer to the endpoint discussion for further details).

Justification for classification or non-classification

The available data on the toxicity to reproduction of the substance do not meet the classification criteria according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.