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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 Febuary 2013 - August 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
OECD 414, GLP. Method and results sufficiently described.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
adopted 22 January 2001
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
additive
Test material form:
liquid
Specific details on test material used for the study:
- Name of test material (as cited in study report): N-(3-Dimethylaminopropyl) methacrylamide
- Supplier: Evonik Röhm GmbH, D-64293 Darmstadt, Germany
- Substance type: organic
- Physical state at room temperature: liquid
- Stability under test conditions: Stability in water: > 160 hours in water; pure: stable for 3 month
- Storage condition of test material: room temperature, light protected

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Italy S.p.A., Calco (Lecco), Italy
- Age at study initiation: 9 weeks old (females), 11 weeks old (males)
- Weight at study initiation:females 206 to 230 g, males at least 350 g)
- Fasting period before study: no data
- Housing: during pre-pairing period and after mating animals were housed no more than 5 of one sex to a cage in polisulphone cages (59.5 x 38 x 18.5cm); during mating period, the rats were housed 1 male to 1 female in clear polycarbonate cages (42.5 x 26.6 x 18.5 cm)
- Diet (e.g. ad libitum): ad libitum (4 RF 21, Mucedola S.r.1., Via G. Galilei, 4, 20019, Settimo Milanese (MI), Italy
- Water (e.g. ad libitum): ad libitum
- Acclimation period: approximately 16 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ±2°C
- Relative humidity: 55 ± 15%
- Air changes (per hr): 15 to 20 cycles/hour
- Photoperiod (hrs dark / hrs light): artificial light 12 h/12 h

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
distilled
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): The required amount of N-(3 dimethylaminopropyl)methacrylamide was dissolved in the vehicle
(distilled water). The formulations were prepared daily (concentrations of 5, 15 and 40 mg/mL) and the concentrations were calculated and
expressed in terms of test item as supplied.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Final results for all levels were within the acceptability limits stated in RTC SOPs for concentration (95-105%) with the exception of Group 2. Analysis was repeated on a new preparation and results were within the acceptability limits.
In this study a 24 hour stability at room temperature was verified in the range from 5 to 40 mg/mL.
According to RTC SOPs, solutions are considered to be stable if concentration after the defined period of storage is still acceptable (95-105%).
Details on mating procedure:
Females were paired one to one in the home cage of the male and left overnight. Vaginal smears were taken daily in the morning from the day after pairing until a positive identification of mating was made. The presence of sperm in the vaginal smear or by the presence of a copulation plug, was considered as Day0 of gestation.
Duration of treatment / exposure:
6 - 19 day post coitum inclusive
Frequency of treatment:
once a day
Duration of test:
14 d (dams were euthanized on gestation day 20)
No. of animals per sex per dose:
24 mated female rats per group exposed.
Control animals:
yes, concurrent vehicle

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS:
- Time schedule: Animals were observed daily for behavioral changes.

DETAILED CLINICAL OBSERVATIONS: Yes (starting from allocation until sacrifice)
- Time schedule: once a day; Morbidity and mortality: at least twice a day including weekends and public holidays, once a day on other days

BODY WEIGHT: Yes
- Time schedule for examinations: Maternal body weights were recorded on GD0, 3, 6, 9, 12, 15, 18 and 20 p.c.starting from Day0 post coitum.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption: The quantity of food consumed by each female was measured on Days 3, 6, 9, 12, 15, 18 and 20 p.c.starting from Day 0 post coitum. 

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data
- Time schedule for examinations:

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
Ovaries and uterine content:
The ovaries and uterus of the females were examined to determine:
gravid uterine weight (will not be obtained from animals found dead or killed during the study), number of corpora lutea, number of implantation sites, number, sex and weight of all live foetuses, number and sex of dead fetuses (foetuses at term without spontaneous movements and breathing), number of intra-uterine deaths and gross evaluation of placentae.
A gross evaluation of placentae was also undertaken.
Fetal examinations:
- External examinations: Yes: all live foetuses
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data
Statistics:
Continuous data (for instance body weight, food consumption, …) amongst group means were assessed by Dunnett's test or a modified test, depending on the homogeneity of data.
Statistical analysis of non-continous data are carried out by means of the Kruskal-Wallis test and intergroup differences between the control and treated groups assessed by a non-parametric version of the Williams test.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:no effects

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: No adverse maternal findings of toxicological relevance were evident at any dose.

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No adverse fetal findings of toxicological relevance were evident at any dose.

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Mortality and fate of females

 

No animals died during the study.

All females were found pregnant at necropsy.

The number of females with live foetuses on gestation Day 20 was 24 in each of the control, low, mid- and high dose groups.

 

Clinical signs

 

No signs of toxicological significance were noted during the study and no signs of reactions to treatment were observed during the dosing period.

 

Body weight and body weight gain

 

No differences in body weight were noted between control and treated groups.

At body weight gain, a statistically significant increase of approximately 21% was noted on Day 6 post coitum in females receiving 400 mg/kg/day and a statistically significant decrease of approximately 29 and 67% was noted on Day 9 post coitum in females receiving 150 and 400 mg/kg/day respectively, when compared to controls. These changes were considered of no toxicological relevance.

 

Food consumption

 

The statistically significant decrease of approximately 11%, detected on Day 9 post coitum in females receiving 400 mg/kg/day, was not considered of toxicological significance.

 

Terminal body weight, uterus weight and absolute weight gain

 

No significant differences in terminal body weight, gravid uterus weight and absolute weight gain were observed in treated groups, when compared to the control group.

Litter data and sex ratios

 

Litter data, mean foetal weight and sex ratios were not affected by treatment.

 

Macroscopic examination of females

                                                                

No treatment-related changes were observed at post mortem examination in treated animals, when compared to the controls.

 

External examination of foetuses

 

The malformation agnatia was detected in one foetus of the mid-dose group, one dead foetus was detected in the high dose group and small foetuses were detected in control and treated groups.

A total of 10 small foetuses (< 2.7 g) were detected; six out of 349 in control females, one out of 367 in low dose females, one out of 344 in mid-dose females and two out of 348 in high dose females.

All these findings were considered incidental and not dose-related.

 

Skeletal examination of foetuses

 

Malformations were detected in control, low and mid-dose groups: no ossification of pubis in one foetus of the control group (associated with no ossification of ischium), one foetus of the low dose group and two foetuses of the mid-dose group. In addition in the mid-dose group malformation such as absence of one rib and absence of mandible was also detected in two foetuses of two different litters.

Considering that some of these alterations were observed in small foetuses (foetal weight < 2.7 g) and were not dose-related, they were considered incidental.

 

Visceral examination of foetuses

 

No findings that could be considered treatment-related were noted at visceral examination of the foetuses in any group.

Applicant's summary and conclusion

Conclusions:
In a developmental toxicity study according to OECD 414 N-Dimethylaminopropyl methacrylamidewas administered to female rats dosed dissolved in distilled water by gavage at dose levels of 0, 50, 150 and 400 mg/kg bw/day from days 6 through 19 of gestation. The maternal NOAEL in this study was found to be 400 mg/kg bw/day and the developmental NOAEL was also found to be 400 mg/kg bw/day.
Executive summary:

In a developmental toxicity study according to OECD 414 N-Dimethylaminopropyl methacrylamide was administered to female rats (Sprague-Dawley, (SD)) by oral gavage at dose levels of 0, 50, 150 and 400 mg/kg bw/day from days 6 through 19 of gestation.

 

The results showed that no animals died during the study. The number of females with live foetuses on gestation Day 20 was 24 in each of the control, low, mid- and high dose groups. No clinical signs of toxicological significance were noted during the study and no signs of reactions to treatment were observed during the dosing period. No differences of toxicological relevance were noted in body weight of females during the study, between control and treated groups. At body weight gain, a statistically significant increase of approximately 21% was noted on Day 6 post coitum in females receiving 400 mg/kg/day and a statistically significant decrease of approximatelly 29 and

67 % was noted on Day 9 post coitum in females receiving 150 and 400 mg/kg/day respectively, when compared to controls. These changes were considered of no toxicological relevance.

No relevant changes were detected in food consumption between treated and control females. No significant differences in terminal body weight, gravid uterus weight and absolute weight gain were observed in treated groups, when compared to the control group.

 

Litter data, mean foetal weight and sex ratios were not affected by treatment. No treatment-related changes were observed at post mortem examination in treated animals, when compared to the controls.

Agnatia was detected in one foetus of the mid-dose group, one dead foetus was detected in the high dose group and small foetuses were detected in control and treated groups. All these findings were considered incidental and not dose-related.

 

Malformations were detected in control, low and mid-dose groups. Considering that some of these alterations were observed in small foetuses (foetal weight < 2.7 g) and were not dose-related, they were considered incidental.

 

No findings that could be considered treatment-related were noted at visceral examination of the foetuses in any group.

 

The maternal NOAEL was therefore 400 mg/kg bw/day.

The developmental NOAEL was therefore 400 mg/kg bw/day.

 

None of the litter parameters recorded (implantations, live fetuses, percentage of male/female fetuses, fetal body weight) were affected.

There were no treatment-related malformations and there were no treatment-related variations that were considered to be adverse. 

 

N- Dimethylaminopropyl methacrylamide folmulation analyses were 95% to 105% of the nominal concentration and were within the acceptable range.

 

The developmental toxicity study in the rat is classified acceptable and satisfies the guideline requirement for a developmental toxicity study (OPPTS 870.3700; OECD 414) in rats.

 

 

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