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Developmental toxicity / teratogenicity

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developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
21 November 2017 - 22 August 2018
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report Date:

Materials and methods

Test guideline
according to
other: - OECD 421 Guideline for testing of chemicals adopted 29.07.16: Reproduction/developmental toxicity screening test.
GLP compliance:
yes (incl. certificate)
Limit test:

Test material

Specific details on test material used for the study:
- Physical form / colour: Pale yellow/solid
- Batch number: 55503625
- Lot number: 02/13
- Purity: 100 %
- Storage conditions: At room temperature in the dark

Test animals

Details on test animals and environmental conditions:
- Source: Charles River
- Females nulliparous and non-pregnant: no
- Age at study initiation: Males: 8 to 10 weeks, Females: 10 to 13 weeks
- Weight at study initiation: Males: 235-348 g, Females: 192-231 g
- Fasting period before study: none
- Housing:
Cages with standard, granulated, S8-15 sawdust bedding (J. Rettenmaier & Söhne)
Premating period (5 animals/cage) Makrolon type IV cages
Mating period (one male and one female/cage) Makrolon type III cages
Postmating, gestation and lactation periods (individual) Makrolon type III cages
- Use of restrainers for preventing ingestion (if dermal): n/a
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: Eight days between arrival and pre-treatment start. After acclimatization period,
the animals were subjected to a 19-day pretest period.

- Temperature (°C): 20-24
- Humidity (%): 30 and 70
- Air changes (per hr): 15-20
- Photoperiod (hrs dark / hrs light): 12 hours fluorescent light/12 hours dark.
IN-LIFE DATES: From: 21 February 2018 To: 22 August 2018

Administration / exposure

Route of administration:
oral: gavage
arachis oil
Details on exposure:
Prepared weekly in Arachis oil and stored at room
temperature and in the dark
- Rate of preparation of diet (frequency): standard Teklad 2014C rat/mouse maintenance diet used
- Mixing appropriate amounts with (Type of food): n/a
- Storage temperature of food: not specified
- Justification for use and choice of vehicle (if other than water): Standard vehicle in these studies
- Concentration in vehicle: n/a
- Amount of vehicle (if gavage): 5mL/Kg
- Lot/batch no. (if required): KMO9422, KMO9047
- Purity: not specified
Analytical verification of doses or concentrations:
Details on analytical verification of doses or concentrations:
The formulations prepared at three different concentrations were analyzed twice over the course of
the study to verify that they were correctly prepared. Controls were also analysed to confirm the ab
sence of the test item.
The test item was used as analytical standard.
12-mL aliquots (in duplicate) were taken from each formulation to be analysed.
Details on mating procedure:
- M/F ratio per cage: 1:1
- Length of cohabitation: Up to 2 weeks
- Proof of pregnancy: vaginal plug and (or) sperm in vaginal smear
- After 14 days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: not specified
- After successful mating each pregnant female was caged: Females were separated when evidence
of mating was detected
- Any other deviations from standard protocol: not specified
Duration of treatment / exposure:
5-8 weeks
Frequency of treatment:
Once daily
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Group 1 (control)
Dose / conc.:
1 mg/kg bw/day (nominal)
Group 2
Dose / conc.:
5 mg/kg bw/day (nominal)
Group 3
Dose / conc.:
20 mg/kg bw/day (nominal)
Group 4
No. of animals per sex per dose:
10 males and 10 females
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: Based on the results of GLP Toxicology Study No. 87-XE-ODBP-10
conducted by the U.S. Army Public Health Command and the preliminary results obtained in the
previous non-GLP study PX87XC 7-day Oral (Gavage) Dose-Range Toxicity Study for OECD 421
conducted at Envigo CRS, S.A.U.
- The high dose level of 20 mg/kg was chosen with the aim of inducing some developmental and/or
maternal toxicity but not death or severe suffering. This dose level was previously tested in toxicology
study No. 87-XE-ODBP-10 and produced signs of systemic toxicity but no mortality or suffering. In
study PX87XC this dose level showed no evidence of toxicity or mortality.
- The intermediate and low dose levels were selected as a descending sequence to demonstrate any
possible exposure-related response.
- Rationale for animal assignment: Random


Bartlett's test, Williams' test, Dunnetts test.
Linear-by-linear test (Cytel, 1995).
Cochran-Armitage test (Cytel, 1995).
Reproductive indices: Estrous cycle, pre-coital interval, mating performance, fertility and gestation length.
Offspring viability indices: Survival indexes, litter size, sex ratio, body weight, clinical signs, ano-genital distances or external examination.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
mortality observed, non-treatment-related
Description (incidence):
The death of two females (numbers 75 and 66) could be considered occasional and not treatment related given that no mortality was recorded at the high dose, due to the incidence observed in the study and to the fact that no test item related effects were observed in these animals during the study. The major factor contributing to their death remained undetermined histologically.
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:
not examined
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
T4 and TSH determinations: a decrease was recorded when compared to Control in adult males (at all doses but mainly at 20 mg/kg/day) and females (at 20 mg/kg/day). It was also observed at 20 mg/ kg/day in offspring males and females on Day 13 of lactation. Despite the effect observed at 20 mg/ kg/day in T4 and TSH determinations, thyroid and parathyroid glands weights were unaffected by treatment. Based on the fact that what was recorded was a decrease in the levels of TSH analyzed and not an increase (which would be related to a possible effect attributable to the components that alter the hormonal function at the level of generation of hypertrophy / follicular hyperplasia) and that no macroscopic findings have been recorded in the pituitary or thyroid / parathyroid glands, this finding cannot be considered as a relevant adverse effect.
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Body-weight-adjusted prostate, seminal vesicles and coagulating gland and spleen weights in males from Group 4 (20 mg/kg/day), epididymides in males from Groups 3 and 4 (5 and 20 mg/kg/day, respectively) and brain weight in females from Group 4 (20 mg/kg/day) differed significantly when compared to control.
Gross pathological findings:
no effects observed
Neuropathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Other effects:
not examined
Description (incidence and severity):
During treatment one female at 1 mg/kg/day (number 62) and one at 5 mg/kg/day (number 76) showed irregular cycles and one female administered at 5 mg/kg/day (number 70) was acyclic. At termination, all reproductive phase females (pregnant) showed diestrus with the exception of 1/9
(number 68) at 1 mg/kg/day and 2/9 (numbers 70 and 71) at 5 mg/kg/day. These females showed different stages of estrous cycle, which indicated they had recovered the cycle.
Details on results:
There was no effect of treatment on the pre-coital interval: all animals mated within four days of mating at the first estrous, with the exception of one female at 5 mg/kg/day, whose pre-coital interval extended to 14 days of mating with one male and 2 days of mating with a second male.
Mating performance was 100% for all groups except 5 mg/kg/day males, for which it was 90%. Fertility was 100% at 0 and 20 mg/kg/day and 90% (9/10) at 1 and 5 mg/kg/day for males and females. These differences cannot be taken into account based on occurrence and lack of dose response.
Gestation length was within the normal range in all treated groups.

Maternal developmental toxicity

Number of abortions:
not specified
Pre- and post-implantation loss:
not specified
Total litter losses by resorption:
not specified
Early or late resorptions:
not specified
Dead fetuses:
not specified
Changes in pregnancy duration:
not specified
Changes in number of pregnant:
not specified
Other effects:
not specified

Effect levels (maternal animals)

Key result
Dose descriptor:
Effect level:
ca. 20 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks on result:
other: No effects seen in any of the parameters tested

Results (fetuses)

Fetal body weight changes:
no effects observed
Changes in sex ratio:
not specified
Changes in litter size and weights:
not specified
Changes in postnatal survival:
not specified
External malformations:
not specified
Skeletal malformations:
not specified
Visceral malformations:
not specified
Other effects:
not specified

Effect levels (fetuses)

Key result
Dose descriptor:
Effect level:
ca. 20 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks on result:
other: No effects seen in any of the parameters tested

Overall developmental toxicity

Key result
Developmental effects observed:

Any other information on results incl. tables

There was no effect on offspring growth. There were no offspring clinical or necropsy signs observed which were indicative of a reaction to DNAN, and there was no relevant effect on litter size, sex ratio, survival indices, body weights, ano-genital distance or nipple areolae.

Applicant's summary and conclusion

The No Observed Adverse Effect Level (NOAEL) for reproductive / developmental toxicity was considered to be 20 mg/kg/day, taking into account that there was no effect on estrous cycle, pre-coital interval, mating performance, fertility and gestation length or in the offspring on survival indexes, litter size, sex ratio, body weight, clinical signs, ano-genital distances or external examination.