6-[C12-18-alkyl-(branched, unsaturated)-2,5-dioxopyrrolidin-1-yl]hexanoic acid

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

key study

Study period:

2012-2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Scientifically well-performed; obtained result sufficiently reliable and robust for classification of the registration substance; equivalent to OECD 414 with reduced number of animals; Non-GLP Justification for read-across: the grouped substances differ only that the registraton substance is a weak acid and the read-across substance is the corresponding weak base. When dissolved in water the read-across supporting substance will be converted to the registration substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

reduced number of animals; 5 animals per group instead of 20

Principles of method if other than guideline:

Aim of the study: In the OECD 422 study on the registration substance, reduced number of pubs were found. The introduced study aimed to clarify whether the effects found in the OECD 422 originated from the fertility impairment or fetotoxicity. The use of reduced number of animals is justified, since the study did not aim to demonstrate the absence of the reproduction toxicity.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(Pentapropylensuccinimido)hexanoic acid, sodium and triethanolamine salts

IUPAC Name:

(Pentapropylensuccinimido)hexanoic acid, sodium and triethanolamine salts

Constituent 2

Reference substance name:

sodium/triethanolamine- 6-(2,5-dioxo-3-C12-18-alkenyl(even and odd, branched, unsaturated)-pyrrolidin-1-yl)hexanoate

EC Number:

800-766-3

Molecular formula:

C22H36NO4.1/2Na.1/2C6H16NO3 - C28H48NO4.1/2Na.1/2C6H16NO3

IUPAC Name:

sodium/triethanolamine- 6-(2,5-dioxo-3-C12-18-alkenyl(even and odd, branched, unsaturated)-pyrrolidin-1-yl)hexanoate

Test animals

Species:

rat

Strain:

Wistar

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Analytical verification of doses or concentrations:

no

Details on mating procedure:

After acclimatization, females will be housed with sexually mature males (1:1) in special automatic mating cages i.e. with synchronized timing to initiate the nightly mating period, until evidence of copulation is observed. This system reduces the variation in the copulation times of the different females. The females will be removed and housed individually if:
- the daily vaginal smear is sperm positive, or
- a copulation plug is observed.
The day of mating will be designated day 0 post coitum.
Male rats of the same source and strain will be used only for mating. These male rats are not considered part of the test system. The fertility of these males has been proven and is continuously monitored.

Duration of treatment / exposure:

day 6 post coitum onwards; last treatment on day 20 post coitum

Frequency of treatment:

once per day

Duration of test:

Caesarean section and necropsy on day 21 post coitum

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

Viability / Mortality: twice daily
Clinical Signs: Daily cage-side clinical observations (once daily, during acclimation and up to day of necropsy)
Food Consumption: recorded at 3-day intervals
Body Weights: recorded daily from day 0 until day 21 post coitum

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

Fetal examinations:

- External examinations: Yes: [all per litter ]
- Soft tissue examinations: Yes: [half per litter ]
- Skeletal examinations: Yes: [half per litter ]
- Head examinations: Yes: [half per litter ]

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Effect levels (fetuses)

Key result

Dose descriptor:

LOAEL

Effect level:

8 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

external malformations

skeletal malformations

visceral malformations

Fetal abnormalities

Key result

Abnormalities:

effects observed, treatment-related

Description (incidence and severity):

Changes in the size or shape of the nasopharyns, nasal septum incompletely fused to the palate at dose of 200 mg/kg bw; Increased number of supernumerary ribs at 40 and 200 mg/kg bw: Small spleen down to dose of 8 mg/kg bw.

Overall developmental toxicity

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

8 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects occurring together with maternal toxicity effects, but not as a secondary non-specific consequence of maternal toxicity effects

Any other information on results incl. tables

Study Summary:

Study design: The study was performed equivalent to the OECD Guideline 414 with the deviation that 5 pregnant animals per dose group were used. The application route was per gavage with water as vehicle. The applied doses were 0, 8, 40 and 200 mg/kg bw. The observations parameters were according to the Guideline as well.

Maternal toxicity: Upon clinical observation no effect indicative of toxicity was found. At 200 mg/kg bw the food consumption and the body weight gain were slightly reduced. No effect was found for animals of 40 and 8 mg/kg bw.

Reproduction data upon Caesarian section: No difference was found for control and treated animals upon investigation on number of corpora lutea, implantation sites and number of live fetuses.

Fetal evaluation:

-         External examination: two fetuses of 200 mg/kg bw exhibited abnormalties; one no lower jaw, small mouth opening and possibly a cleft palate and the other a cleft palate.

-         Visceral abnormalities: all fetuses of 200 mg/kg bw had small spleen and incomplete fusion of nasal septum to palate; small spleen was found down to dose level of 8 mg/kg bw.

-         Skeletal abnormalities: abnormalities were found in all fetuses of 200 mg/kg bw, comprising thin skull zygomatic jugal arch, abnormal curvature of pectoral girdle clavicle, absent humerus deltoid tuberosity in forelimb, short mid region of rib cage, abnormal curvature of hyoid body and abnormal spacing of zygomatic arch structures; increased number of supernumerary ribs was found at 200 and 40 mg/kg bw.

Tab: Incidence of some fetal toxicity found down to mid/low doses
a) Small spleen in intrauterine exposed fetuses
	Control n=32	8 mg/kg bw n=36	40 mg/kg bw n=35	200 mg/kg bw n=32
Spleen small or small severe (total)	1 (3%)	4 (11%)	17 (49%)	32 (100%)
Small (ca. 75% of expected size)	1 (3%)	4 (11%)	16 (46%)	5 (16%)
Small severe (ca. 50% of expected size)	0 (-)	0 (-)	1 (3%)	27 (84%)
b) Supernumerary ribs, rudimentary in intrauterine exposed fetuses
	Control n=29	8 mg/kg bw n=33	40 mg/kg bw n=33	200 mg/kg bw n=28
Left	7 (24%)	8 (24%)	26 (79%)	24 (82%)
Right	8 (28%)	5 (15%)	24 (73%)	25 (89%)

 

Conclusion: Clear toxic effects were found for fetuses at doses that were not associated with an apparent maternal toxicity.

Applicant's summary and conclusion

Conclusions:

The registration substance was assessed based on the data on read-across supporting substance, in which clear fetotoxicity was found at doses that were not associated with apparent maternal toxicities. The study is considered to be valid to demontrate the developmental toxicity of the registration substance. The assignment of Cat 2:R61 is justified according to 67/548/EEC (DSD).

Executive summary:

The developmental toxicity of the registration substance was assessed based on data on the read-across substances, (Pentapropylensuccinimido)-hexanoic acid, sodium and triethanolamine salts.

(Pentapropylensuccinimido)-hexanoic acid, sodium and triethanolamine salts was investigated for its developmental toxicity equivalent to the OECD Guideline 414 with the deviation that 5 pregnant animals per dose group were used. The application route was per gavage with water as vehicle. The applied doses were 0, 8, 40 and 200 mg/kg bw. The observations parameters were according to the Guideline as well.

No significant clinical effect was found for all treated dams. At 200 mg/kg bw the food consumption and the body weight gain were slightly reduced. No effect was found for animals of 40 and 8 mg/kg bw.

With respective to the reproduction performance of the treated animals, the investigated parameters such as number of corpora lutea, implantation sites and number of live fetuses were comparable to those of control animals.

Upon examination of fetuses, increased frequency of a small spleen was noted down to the dose level of 8 mg/kg bw/day. Increased number of supernumerary ribs (rudimentary) was noted at the dose levels of 200 and 40 mg/kg bw/day. In addition, changes in the size or shape of the nasopharyns, nasal septum incompletely fused to the palate as well as several abnormalitiers and variations in skeleton were noted at the dose level of 200 mg/kg bw/day.

Based on the fetotoxicity found down to dose of 8 mg/kg bw, the LOAEL of 8 mg/kg bw was established.