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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive toxicity
Remarks:
based on test guideline (migrated information)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP Guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
Deviations:
yes
Remarks:
extended by additional examinations
Principles of method if other than guideline:
One-generation study (OECD 415; May 1983), extended by additional examinations (estrous cycle, sperm parameters, organ weight determinations, extended histopathology, signs of sexual maturation in selected pups) that are required in a two-generation study (OECD 416; Jan. 2001)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): N-(N-Octyl)Pyrrolidone; Substance No. 01/0525-1
- Physical state: colorless liquid
- Analytical purity: 99.2 %
- Lot/batch No.: AL. Nr. 94-0981
- Date of production: JuIy 2000
- Storage condition of test material: room temperature

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Dr. Karl Thomae GmbH, Biberach/Riss, FRG
- Age at study initiation: 34 days (43 days at study initiation)
- Mean weight at study initiation: 183 (114 - 194) g for the males , 148 (132 - 160) g for the females.
- Fasting period before study: none
- Housing: singly in type DK III stainless steel wire cages
- Diet: ground Kliba maintenance diet rat/mouse/hamster, 343 meal, supplied by Klingentalmühle AG, CH-4303 Kaiseraugst, Switzerland, ad libitum
- Water: Tap water ad libitum
- Acclimation period: 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: feed
Details on mating procedure:
- M/F ratio per cage: 1/1
- Length of cohabitation: over night
- Proof of pregnancy: [sperm in vaginal smear] referred to as [day 0] of pregnancy
- After successful mating each pregnant female was caged (how): individual
Analytical verification of doses or concentrations:
yes
Duration of treatment / exposure:
Premating exposure period (males): 75 days
Premating exposure period (females): 75 days
Frequency of treatment:
continuously
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 100, 300, 1000 mg/kg bw/day
Basis:
nominal in diet
No. of animals per sex per dose:
25 males and 25 females
Control animals:
yes
Positive control:
not done

Examinations

Parental animals: Observations and examinations:
N-Octylpyrrolidone was administered to groups of 25 male and 25 female healthy young Wistar rats (F0 parental generation) as a homogeneous addition to the food in different dietary concentrations, which were adjusted regularly to obtain a constant test substance intake of 0, 100, 300 and 1000 mg/kg bw/day. At least 75 days after the beginning of treatment, F0 animals were mated to produce a litter. After litter standardization on day 4 p.p. (post partum) F1 pups were reared until weaning. At this time 25 male and 25 female pups per group were selected and allowed to grow up until sexual maturity. The latter rats ("selected F1 animals") were treated with the compound after weaning (day 21 p.p.) until sacrifice at the same dose levels and in the same manner as the F0 parental animals. The study was terminated with the sacrifice and gross necropsy of all F0 and F1 animals. The state of health of the F0 and F1 rats was checked each day, and the F0 parental animals were examined for their mating and reproductive performance.
Food consumption of the F0 parents was determined regularly during premating (once weekly over a period of 6 days each), and during gestation (clays 0-7, 7-14, 14-20) and lactation periods (days 1-4, 4-7, 7-14). Food consumption of the selected F1 animals was determined once weekly after weaning (over a period of 6 days). In general, body weights of F0 parents and selected F1 animals were determined once weekly (each time for a period of 7 days). However, F0 females were weighed on days 0, 7, 14 and 20 of gestation and on days 1, 4, 7, 14 and 21 of lactation. The body weights of the selected F1 animals were additionally determined on the day of preputial separation/ vaginal opening.
Oestrous cyclicity (parental animals):
Estrous cycle data were evaluated in F0 generation females over a three week-period prior to mating and throughout the following mating period until individual evidence of mating occurred. Moreover, the estrous stage of each F0 female was determined on the day of scheduled sacrifice.
Sperm parameters (parental animals):
Various sperm parameters (sperm head counts and morphology) were assessed in all control and high dose F0 generation males, while sperm motility was examined in the F0 males of all groups at scheduled sacrifice or after appropriate staining.
Litter observations:
All F1 pups were sexed on the day of birth and were weighed on the subsequent day as well as on day 4 after birth. their viability was recorded. Standardized litters were weighed on days 7, 14 and 21 p.p. After weaning the non-selected pups were subjected to gross necropsy (including weight determinations of brain, spleen and thymus in one pup/sex/litter). The selected FI weanlings were reared and the time of sexual maturation (day of preputial separation/ vaginal opening) was determined. Thereafter, these pups were killed and examined macroscopically at necropsy.
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals
- Maternal animals: All surviving animals


GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera


HISTOPATHOLOGY / ORGAN WEIGHTS
Tissues were prepared for microscopic examination and weighed, respectively.
Postmortem examinations (offspring):
SACRIFICE
- The F1 offspring not selected as parental animals and all F2 offspring were sacrificed at day of preputial separation/ vaginal opening
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination)


GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera


HISTOPATHOLOGY / ORGAN WEIGTHS
Tissues were prepared for microscopic examination and weighed, respectively.

Results and discussion

Results: P0 (first parental generation)

Effect levels (P0)

open allclose all
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Fertility
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male
Basis for effect level:
other: systemic toxicity
Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day
Based on:
test mat.
Sex:
female
Basis for effect level:
other: systemic toxicity

Results: F1 generation

Effect levels (F1)

Dose descriptor:
NOAEL
Generation:
F1
Effect level:
300 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Slightly decreased mean body weights in F1 pups of both sexes, statistically significant from day 7 until day 21 p.p. (13 % at maximum). Slightly impaired weight gain of F1 pups from day 4 p.p. until weaning (average -15 %)

Overall reproductive toxicity

Reproductive effects observed:
not specified

Any other information on results incl. tables

Results summary

The following test substance-related findings were observed:

Test group 03 (1038.9 mg/kg body weight/day)

Parental animals:

CLINICAL EXAMINATIONS / REPRODUCTIVE PERFORMANCE / CLINICAL PATHOLOGY / PATHOLOGY

- Decreased food consumption in F0 females, slightly but statistically significantly (up to 9 %) during premating from study week 6 until study week 10, from days 0 - 20 p.c. and after weaning study week 18 – 19

- Slightly decreased (up to 7 %) mean body weights in F0 females, statistically significant during premating (weeks 8-10), during gestation, on lactation days 1-4 and after weaning (weeks 18-19)

- Significantly decreased average body weight gain in F0 females during entire premating (-10 %), highest decrease during weeks 4-5 (-35 %); decreased weight gain

- during second gestation week (-18 %), regain of weight from day 4 p.p. until weaning (+58 %)

- Significantly increased absolute and relative liver weights in males and females

. Significantly increased relative weight of the thyroid glands in males

- Minimal to slight central hypertrophy of hepatocytes in the liver of three males and all females

- Higher incidence of hypertrophy/ hyperplasia in the thyroid glands of males

-Higher incidence of altered colloid in the thyroid glands of males F1 pups / selected F1 animals (reared F1weanlings)

 

offspring:

CLINICAL EXAMINATIONS / PUP ORGAN WEIGHTS / SEXUAL MATURATION

- Slightly decreased mean body weights in F1 pups of both sexes, statistically significant from day 7 until day 21 p.p. (13 % at maximum)

. Slightly impaired weight gain of F1 pups from day 4 p.p. until weaning (average -15 %)

 

Test group 02 (311.8 mg/kg body weight/day)

F0 parental animals

CLINICAL EXAMINATIONS / REPRODUGTIVE PERFORMANCE / CLINICAL PATHOLOGY / PATHOLOGY

-Decreased mean body weights (maximum -6%), statistically significant in the last 2 weeks prior to mating as well as body weight gain (average -9% during premating) in the F0 females.

- Significantly increased absolute (males, only) and relative liver weights in males and females

- Significantly increased relative weight of the thyroid glands in males

- Higher incidence of hypertrophy hyperplasia in the thyroid glands of males

- Higher incidence of altered colloid in the thyroid glands of males

 

F1 pups 1 selected F1 animals (reared F1 weanlings)

CLINICAL EXAMINATIONS / PUP ORGAN WEIGHTS / SEXUAL MATURATION

- no test substance-related findings

 

Test group 01 (103.1 mg/kg body weight/day)

F0 parental animals

CLINICAL EXAMINATIONS / REPRODUOTIVE PERFORMANCE / CLINICALPATHOLQGY / PATHOLOGY

- No test substance-related findings

 

F1 pups 1 selected F1 animals (reared F1 weanlings)

CLINICAL EXAMINATIONS / PUP ORGAN WEIGHTS / SEXUAL MATURATION

No test substance-related findings

 

CONCLUSION

There were no indications that N-Octylpyrrolidon adversely affected reproductive performance or fertility of the F0 parental animals at dose levels of 100, 300 and 1000 mg/kg body weight/day.

 

Signs of general systemic toxicity were noted in the high and mid dosed F0 parental females, such as reduced food consumption and body weight, mainly during premating and gestation. Pathology identified the liver and the thyroid glands as target organs. However, the increased liver weights in mid and high dose animals as well as the occurrence of central hypertrophy/ hyperplasia in the liver of high dose animals are considered to be test substance-related but rather reflecting an adaptive effect representing microsomal enzyme induction than a toxicologically relevant and adverse finding. In addition, the thyroid findings are considered to be secondary to the observed liver findings.

The F1 pups of the high dose groups showed decreased mean body weights as well as body weight gain in either sex until weaning. This test substance related effect disappeared during post-weaning development of the selected F1 offspring, thus being a temporary effect on postnatal development. This slight retardation of development was present exclusively at a dose level where maternal toxicity was noted in the F0 females, too. Moreover, no other test substance-induced signs of developmental toxicity were obtained in F1 pups and selected F1 animals raised after weaning until sexual maturity. Thus, under the conditions of the present extended one-generation study the NOAEL (no observed adverse effect level) could be fixed for:

- fertility and reproductive performance of the F0 parental rats: 1000 mg/kg body weight/day In both genders

- general systemic toxicity of the test substance: 1000 mg/kg body weight/day in F0 parental males; 100 mg/kg body weight/day in F0 parental females

- developmental toxicity (growth and development of the F1 offspring until sexual maturity): 300 mg/kg body weight/day in both genders

Applicant's summary and conclusion

Conclusions:
There were no indications the substance adversely affected reproductive performance or fertility of the F0 parental animals at dose levels of 100, 300 and 1000 mg/kg bw/day.
Signs of general systemic toxicity were noted in the high and mid dosed F0 parental females, such as reduced food consumption and body weight, mainly during premating and gestation. Pathology identified the liver and the thyroid glands as target organs. However, the increased liver weights in mid and high dose animals as well as the occurrence of central hypertrophy/hyperplasia in the liver of high dose animals are considered to be test substance-related but rather reflecting an adaptive effect representing microsomal enzyme induction than a toxicologically relevant and adverse finding. In addition, the thyroid findings are considered to be secondary to the observed liver findings.
The F1 pups of the high dose groups showed decreased mean body weights as well as body weight gain in either sex until weaning. This test substance related effect disappeared during postweaning development of the selected F1 offspring, thus being a temporary effect on postnatal development. This slight retardation of development was present exclusively at a dose level where maternal toxicity was noted in the F0 females, too. Moreover, no other test substance-induced signs of developmental toxicity were obtained in F1 pups and selected F1 animals raised after weaning until sexual maturity.

Thus, under the conditions of the present extended one-generation study the NOAEL (no observed adverse effect level) could be fixed for:
Fertility and reproductive performance of the F0 parental rats = 1000 mg/kg bw/day;
General systemic toxicity = 1000 mg/kg bw/day in F0 parental males, 100 mg/kg bw/day in F0 parental females;
Developmental toxicity (growth and development of the F1 offspring until sexual maturity) = 300 mg/kg bw/day in both genders.