3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 Aug - 7 Sept 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP-guideline study with acceptable restrictions. Dosing was performed on gestation day 6-17, 10 rats per dose group, no justification for the selected dose groups, analytical purity of the test substance was not specified.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

dosing performed on gestation day 6-17, 10 rats per dose group, no justification for the selected dose groups

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate

EC Number:

261-665-2

EC Name:

3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate

Cas Number:

59219-71-5

Molecular formula:

C18H36O2

IUPAC Name:

3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate

Details on test material:

- Name of test material (as cited in study report): isononyl isononanoate
- Physical state: colourless liquid
- Analytical purity: no data
- Storage condition of test material: at room temperature

Test animals

Species:

rat

Strain:

other: Sprague-Dawley Crl CD(SD) IGS BR

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River France, Saint Aubin-lès-Elbeuf, France
- Age at study initiation: approximately 11 weeks
- Weight at study initiation: 272 g (mean)
- Housing: the animals were housed individually in suspended wire-mesh cages (43.0 cm x 21.5 cm x 18.0 cm). A metal tray containing autoclaved sawdust (SICSA, Alfortville, France) was placed under each cage.
- Diet: A04 C pelleted diet, batch No. 90528 (U.A.R., Villemoisson-sur-Orge, France), ad libitum
- Water: tap water filtered using a 0.22 micron filter, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 50 ± 20
- Air changes (per hr): approximately 12
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 17 Aug 2000 To: 7 Sept 2000

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: the solutions were prepared daily prior to dosing and homogenised using a magnetic stirrer. The solutions were stirred continously during the dosing procedure. The doses were adjusted according to the most recently recorded body weight.

VEHICLE
- Concentration in vehicle: 10, 33.33 and 100 mg/mL
- Amount of vehicle (if gavage): 3 mL/kg bw
- Lot/batch no. (if required): 107H1649 (Sigma, France)

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: purchased timed pregnant
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy

Duration of treatment / exposure:

Day 6-17 of gestation

Frequency of treatment:

Daily, 7 days/week

Duration of test:

12 days, Day 6-20 of gestation

Doses / concentrations

Remarks:

Doses / Concentrations:
30, 100 and 300 mg/kg bw/day
Basis:
other: nominal as gavage

No. of animals per sex per dose:

10 P females

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily for mortality and signs of morbidity, at least once daily for clinical signs
- Cage side observations included: evidence of absorption/resorption, signs of toxicity

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: gestation day 2 (prior to administration), 6, 9, 12, 15, 18 and 20 (prior to sacrifice). The net body weight change was calculated as (body weight on day 20 minus body weight on day 2) minus weight of gravid uterus.


FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: ovaries, uterus, placenta, thoracic organs, abdominal organs

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: number and distribution of dead and live foetuses

Fetal examinations:

- External examinations: Yes: all per litter (sex, body weight, external anomalities and malformations)
- Soft tissue examinations: Yes: half per litter (stored in Bouin's fluid)
- Skeletal examinations: Yes: half per litter (eviscerated, skeletons stained with alizarin red S)
- Head examinations: No

Statistics:

Mean values were compared by one-way analysis of variance and Dunnett's test. Percentage values were compared by Fisher's exact probability test.

Indices:

Preimplantation loss:
((Number of corpora lutea - Number of implantation sites) / Number of corpora lutea) x 100

Post-implantation loss:

((Number of implantation sites - Number of live fetuses) / Number of implantation sites) x 100

Fetal findings:

(Number of fetuses with a particular finding/ total number of fetuses examined) x 100

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes. Remark: 300 mg/kg bw/day: reduced body weight gain

Details on maternal toxic effects:
Systemic effects:
1/10 females in the control group died on gestation day 7. No clinical signs were observed prior to death, but during the histopathological examination the lungs were reddish and dilated. This may have been caused by mis-dosing, although the cause was not established.

In 1/10 rats in the high-dose group, piloerection, abdominal breathing and chromorhinorrea were observed on gestation day 8 to 11, indicating a poor health condition.

The female that showed clinical signs of toxicity also had a body weight loss of approximately 10% from gestation day 6 to 12. The body weight in females in the high-dose group was significantly reduced on day 15 and 18 (see Table 1 under 'Any other information on results incl. tables'). The body weight gain was significantly reduced during gestation day 6 to 18, indicating an effect during the entire dosing period (see Table 2 under 'Any other information on results incl. tables'). The total body weight gain was approximately 25% lower than in the control group. The food consumption was reduced in the high-dose group on gestation day 6-18, compared with the control group, although not statistically significant.

The female exhibiting clinical signs had brownish content of the uterus and dilatation of the cervix. The effects may be toxicologically relevant. No other treatment-related effects were noted.

Fertility effects:
There was no statistically significant effect on the fertility index, corpora lutea, resorptions, pre-implantation loss, post-implantation loss, fetal viability (in utero), gravid uterus weight and number of fetuses.

The slight, but not significant, increase in resorptions and pre-implantation losses observed in the high-dose group is attributable to a single female that was in poor health (14/37 pre-implantation losses). One female in the high-dose group exhibited clinical signs, had body weight loss and histopathological findings. The same female had several resorptions and dead fetuses. This is considered to be a consequence of the poor maternal health condition and is not a reproductive effect. All results were within the historical data range (see Table 6 under 'Any other information on results incl. tables').

Effect levels (maternal animals)

1

Dose descriptor:

LOAEL

Effect level:

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

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
There were no statistically significant difference in post-implantation loss, embryo survival, sex ratio, body weight, malformations and abnormalities beween the control group and the treatment groups (see Table 4 and 5).

The slight, but not significant, increase in post-implantation losses observed in the high-dose group is attributable to a single female (7/12 post-implantation losses) that was in poor health. This is considered to be a consequence of the poor maternal health condition and is not a reproductive effect. All results were within the historical data range (see Table 6 under 'Any other information on results incl. tables').

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

>= 300 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: developmental toxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

 

Table 1: Body weights, g (mean ± SD)

Dose group	Control	30 mg/kg bw/day	100 mg/kg bw/day	300 mg/kg bw/day
Gestation day 2	250 ± 14	248 ± 13	248 ± 12	247 ± 15
Gestation day 6	272 ± 15	272 ± 13	272 ± 12	271 ± 14
Gestation day 9	287 ± 18	284 ± 17	280 ± 17	273 ± 26
Gestation day 12	311 ± 21	305 ± 16	295 ± 28	285 ± 31
Gestation day 15	330 ± 24	324 ± 19	315 ± 22	303 ± 19*
Gestation day 18	370 ± 28	365 ± 22	348 ± 28	332 ± 25**
Gestation day 20	400 ± 31	400 ± 26	385 ± 26	370 ± 25

*d-ANOVA + Dunnett-test, p < 0.05

**d-ANOVA + Dunnett-test, p < 0.01

 

 

Table 2: Body weight gain, g (mean % change)

Dose group	Control	30 mg/kg bw/day	100 mg/kg bw/day	300 mg/kg bw/day
Day 2 to 6	9.1	9.6	9.8	9.9
Day 6 to 9	5.0	4.2	3.1	0.6
Day 9 to 12	8.3	7.5	5.3	4.7
Day 12 to 15	6.3	6.3	7.0	6.8
Day 15 to 18	12.0	12.5	10.5	9.6
Day 18 to 20	8.2	9.7	10.8	11.6
Day 2 to 20	60.2	61.0	55.7	50.2*
Day 6 to 18	35.4	34.0	28.1	22.7**
Day 6 to 12	13.7	12.0	8.6	5.2*

*d-ANOVA + Dunnett-test, p < 0.05 (based on absolute mean body weight)

**d-ANOVA + Dunnett-test, p < 0.01 (based on absolute mean body weight)

 

 

 

Table 3: Reproduction parameters for dams with live foetuses

Dose group	Control	30 mg/kg bw/day	100 mg/kg bw/day	300 mg/kg bw/day
Number of dams at term	9	10	10	10
Number of pregnant dams at term	9	10	10	10
Corpora lutea (total)	144	166	156	173
Corpora lutea per dam (mean ± SD)^a	16.0 ± 1.6	16.6 ± 3.0	15.6 ± 3.4	17.3 ± 2.5
Implantation sites (total)	124	141	131	136
Implantation sites^a(mean ± SD)	13.8 ± 1.6	14.1 ± 1.9	13.1 ± 2.8	13.6 ± 2.1
Pre-implantation loss (total)^b	20	25	25	37
Pre-Implantation loss (%)	13.9	15.1	16.0	21.4
Resorptions + scars (total)^b	6	1	9	11
Resorptions + scars (% of implantation sites)^b	4.5	0.7	6.9	8.1
Resorptions + scars (mean ± SD)^a	0.7 ± 1.1	0.1 ± 0.3	0.9 ± 1.5	1.1 ± 2.1
Implant scars (total)	0	0	0	0
Early resorptions (total)^b	3	1	8	11
Early resorptions as No. per dam (mean ± SD)^a	0.3 ± 0.7	0.1 ± 0.3	0.8 ± 1.5	1.1 ± 2.1
Late resorptions (total)^b	3	0	1	0
Late resorptions as No. per dam (mean ± SD)^a	0.3 ± 1.0	0.0 ± 0.0	0.1 ± 0.3	0.0 ± 0.0
Fetuses (total)	118	140*	122	125
Fetuses per dam (mean ± SD)^a	13.1 ± 2.3	14.0 ± 2.1	12.2 ± 4.2	12.5 ± 3.7
Live foetuses (%)	98.3	100.0	100.0	99.2
Dead foetuses (%)	1.7	0.0	0.0	0.8
Uterus weight(mean ± SD)^a	79.3 ± 11.2	84.1 ± 12.8	72.1 ± 23.8	69.7 ± 21.2

^ad-ANOVA +Dunnett-test based on pooled variance

^bFishers exact test

*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^b(m/f)	116 (62/56)	140*(74/66)	122 (58/64)	124 (63/62)
Sex ratio (m/f)	0.53/0.47	0.53/0.47	0.47/0.53	0.50/0.50
Weights of live foetuses, g (mean ± SD)^a	3.79 ± 0.32	4.01 ± 0.24	3.91 ± 0.47	3.46 ± 0.54

^ad-ANOVA +Dunnett-test based on pooled variance

^bFishers exact test

*p < 0.05

 

 

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
External malformations, number (% of total)^b	1 (0.8%)	0 (0%)	0 (0%)	0 (0%)
External anomalies, number (% of total)^b	0 (0%)	0 (0%)	0 (0%)	0 (0%)

^ad-ANOVA +Dunnett-test based on pooled variance

^bFishers exact test

*p < 0.05

 

 

Table 6: Historical data

	Mean value (range)
Number of pregnant dams at term	829
Corpora lutea per dam	17.0 (14.6-21.5)
Implantation sites	14.0 (12.0-16.0)
Pre-implantation loss as % of corpora lutea	17.1 (5.0-30.0)
Post-implantation loss as % of corpora lutea	4.6 (0.0-16.6)
Resorptions	0.5 (0.0-2.3)
Live foetuses, % of implantation sites	95.4 (83.4-100)

Applicant's summary and conclusion

Conclusions:

Hexanoic acid,-3,5,5-trimethyl-,-3,5,5-trimethylhexyl ester (CAS 59219-71-5) has no effect on intrauterine development.