Fatty acids, C16-18, 2-octyldodecyl esters

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Study period:

28 Jun - 21 Jul 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study with acceptable restrictions. Short treatment period (Day 6-15 of gestation), body weight was recorded on Day 0, 6, 16 and 20 only, food consumption was not recorded, the analytical purity of the test substance was not specified.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

exposure from Day 6 to Day 15 of gestation, body weight was recorded on Day 0, 6, 16 and 20, food consumption was not recorded

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

111937-03-2

EC Number:

601-141-6

Cas Number:

111937-03-2

IUPAC Name:

111937-03-2

Details on test material:

- Name of test material (as cited in study report): isononanoic acid, mixed hexadecyl-octadecyl esters
- Physical state: colourless liquid
- Analytical purity: no data
- Lot/batch No.: 27533249
- Expiration date of the lot/batch: Sep 1994
- Storage condition of test material: at room temperature in the dark

Test animals

Species:

rat

Strain:

other: Sprague-Dawley, CD

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Wiga GmbH, Sulzfeld, Germany
- Age at study initiation: 8 weeks
- Weight at study initiation: 202.6 ± 20.4 g - 219 ± 25.6 g (range of group mean values)
- Housing: the animals were housed individually in Makrolon Type M3 cages (Ebeco, Castrop-Rauxel, Germany), on standard softwood bedding (ARWI-Center, Essen, Germany)
- Diet: pelleted Altromin Maintenance Diet 1324 (Fa. Altromin GmbH, Lage, Germany), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-24
- Humidity (%): 48-82
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12 (lux units 50 - 550)

IN-LIFE DATES: From: 28 Jun 1994 To: 21 Jul 1994

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% sodium carboxymethylcellulose + 0.25% Cremophor in aqua dest.

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was prepared daily before administration, adjusted to the body weight measured on Day 6 of gestation.

VEHICLE
- Concentration in vehicle: 1, 3, 10% (10, 30, 100 mg/mL)
- Amount of vehicle (if gavage): 10 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The mixture of the test item was analysed once to verify the actual concentration. The measured concentration was within the expected range. The nominal concentrations 1 % (100 mg/kg bw/day), 3 % (300 mg/kg bw/day) and 10 % (1000 mg/kg bw/day) were measured to be 1.1%, 3.0% and 10.5%, respectively.

Details on mating procedure:

- Any other deviations from standard protocol: Primiparous time-mated females were used. The females were mated at the supplier with an accurate day of mating and received at the testing facility on gestation day 0.

Duration of treatment / exposure:

Day 6-15 of gestation

Frequency of treatment:

daily, 7 days/week

Duration of test:

10 days; Day 6-15 of gestation

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300 and 1000 mg/kg bw/day
Basis:
other: nominal dose

No. of animals per sex per dose:

23 P females (100 and 300 mg/kg bw/day)
24 P females (control, 1000 mg/kg bw/day)

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: on Day 0 (prior to administration), 6, 16 and 20 of gestation

FOOD CONSUMPTION: No

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: gross macroscopic examination of all reproductive and gender-specific organs, with emphasis on the uterus, uterine contents, position of the fetuses in the uterus and number of corpora lutea

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
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: weight of fetuses

Fetal examinations:

- External examinations: Yes, all fetuses
- Soft tissue examinations: Yes, half per litter (146 fetuses of group 1, 133 fetuses in group 2, 169 fetuses in group 3 and 162 fetuses in group 4)
- Skeletal examinations: Yes, half per litter (159 fetuses of group 1, 144 fetuses in group 2, 178 fetuses in group 3 and 172 fetuses in group 4)
- Head examinations: No

Group 1: control
Group 2: 100 mg/kg bw/day
Group 3: 300 mg/kg bw/day
Group 4: 1000 mg/kg bw/day

Statistics:

If the variables could be assumed to follow a normal distribution, the Dunnett-Test, based on pooled variance, was applied for comparion between groups. The Steel-Test was applied when the data could not be assumed to follow a normal distribution. Fisher's Exact test for 2x2 tables was applied if the variables could be dichotomized without loss of information (Bonferroni-Holm-corrected).

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
There was no mortality during the study period. No signs of systemic toxicity were observed. The mean body weight of the mid-dose group was statistically significantly increased on Day 16 and 20 of the study period (see Table 1). This considered to be an incidental observation, as the body weight gain over the study period was comparable between the control and treatment groups (58.9, 67.8, 57.4 and 59.6 g for the control, 100, 300 and 1000 mg/kg bw/day group, respectively). One female in each of the control group and the low-dose group was not pregnant, while all the pregnant females had viable fetuses (see Table 2).

No substance-related effects on the reproductive parameters (number of corpora lutea, implantation sites, pre-implantation loss, post-implantation loss, embryonic deaths, embryonic resorptions, fetal resorptions, live fetuses, dead fetuses) were observed (see Table 3). The necropsy and macroscopic examination did not show any treatment-related effects. One female in the high-dose group had blood in the uterine horn, but this is not considered to be treatment-related as no other effects were observed.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

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

Basis for effect level:

other: developmental toxicity

2

Dose descriptor:

NOAEL

Effect level:

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

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
The external examination of the foetuses did not reveal any treatment-related macroscopical effects. The skeletal examination showed a statistically significant increase in the number of foetuses with 6 ossified sternebrae in the high-dose group (see Table 5). As there were no increases in ossification anywhere else and no overall increase in abnormal findings for this group, the result is considered to be incidental. The results for the remaining offspring parameters (body weight, placental weight, sex ratio) were comparable between the control and treatment groups.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

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

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Table 1: Body weights

Dose group	Control	100 mg/kg bw/day	300 mg/kg bw/day	1000 mg/kg bw/day
Gestation day 0	212.3	202.6	219.7	209.0
Gestation day 6	263.1	255.5	273.5	259.4
Gestation day 16	340.7	338.6	361.7*	341.5
Gestation day 20	403.3	400.7	428.0*	407.9

*Dunnett-Test based on pooled variance, p < 0.05

 

Table 2: Summary of mating performance of the females

Dose group	Control	100 mg/kg bw/day	300 mg/kg bw/day	1000 mg/kg bw/day
No. of mated females	24	23	23	24
No. of pregnant females*	23	22	23	24
No. of premature litters**	0	0	0	0
No. of mortalities	0	0	0	0

*Included in the statistical analysis

**Premature litter is an event in the cage immediately before the caesarean section

 

Table 3: Reproduction parameters for dams with live foetuses

Dose group	Control	100 mg/kg bw/day	300 mg/kg bw/day	1000 mg/kg bw/day
Number of dams	23	22	23	24
Corpora lutea (total)	376	343	403	390
Corpora lutea (mean±SD)	16.3±1.5	15.6±1.2	17.5±1.6	16.2±2.3
Implantation sites (total)	316	301	367	346
Implantation sites^aas: -% of corp. lutea - mean±SD	84.0 13.7±3.7	87.8 13.7±2.5	91.1 16.0±1.9	88.7 14.4±3.1
Pre-implantation loss (total)^b	60	42	36*	44
Pre-Implantation lossas % of corpora lutea	16.0	12.2	8.9	11.3
Post-implantation loss^b	11	24	20	12
Post-implantation loss as % of implantation sites	3.5	8.0	5.4	3.5
Embryonic deaths total^b	11	24	20	12
Embryonic resorptions (total)^a	9	18	20	10
Embryonic resorptions as % of implantation sites (mean±SD)	2.8±0.4	6.0±0.8	5.4±0.9	2.9±0.4
Foetal resorptions (total)^a	2	6	0	2
Foetal resorptionsas % of implantation sites(mean±SD)	0.6±0.1	2.0±0.3	0	0.6±0.1
Fetuses per dam (mean±SD)	13.3±3.6	12.6±3.1	15.1±2.4	13.9±2.7
Live foetuses^a	305	277	347	334
Dead foetuses^a	0	0	0	0
Malformed foetuses	0	0	0	0
Uterus weight^c(mean±SD)	81.3±24.1	77.4±18.0	97.0±15.7*	88.8±18.3

^aSteel Test

^bFishers Exact Test (Bonferroni-Holm-Corrected)

^cDunnett-Test based on pooled variance

*p < 0.05

 

Table 4: Developmental parameters for offspring

Dose group	Control	100 mg/kg bw/day	300 mg/kg bw/day	1000 mg/kg bw/day
Number of live foetuses (m/f)	305 (154/151)	277 (141/136)	347 (162/185)	334 (165/169)
Sex ratio (m/f)	0.51/0.49	0.51/0.49	0.47/0.53	0.49/0.51
Weights of live foetuses (mean±SD)	4.1±0.8	4.1±0.6	4.4±0.8	4.2±0.6
No. of runts	1	2	1	2

Table 5: results of skeletal examination of offspring

Dose group	Control	100 mg/kg bw/day	300 mg/kg bw/day	1000 mg/kg bw/day
No abnormal findings, number (% of total)	10 (6.3%)	12 (8.3%)	32 (18.0%)**	10 (5.8%)
6 ossified sternebrae, number (% of total)	124 (78.0%)	120 (83.3%)	151 (84.8%)	153 (89%)**

** Fishers Exact Test (two-sided), p < 0.01

 

Applicant's summary and conclusion

Conclusions:

The test substance had no effect on intrauterine development
CLP: not classified
DSD: not classified