Registration Dossier

Administrative data

Endpoint:
developmental toxicity
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:
2001
Report Date:
2001

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Qualifier:
according to
Guideline:
other: For the inhalation exposure, the OECD guideline method 412 was considered.
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-Vinyl Pyrrolidone
- Physical state: liquide/colourless, clear/homogenous
- Analytical purity: 99.8%
- Purity test date: prior to the study and after the in-life phase of the study (reanalysis)
- Lot/batch No.: Reinkolonne K350C, probe-number: 03102
- Stability under test conditions: the degree of purity was equal before the study and after in-life phase of the study, so the compound was stable under test conditions
- Storage condition of test material: room temperature (not < 15°C)

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Sulzfeld
- Age at study initiation: about 75-80 days
- Weight at study initiation: mean weight approx. 170g
- Housing: singly from day 0-20 post coitum; underneath the cages, waste trays were fixed containing bedding material
- Diet: rat/mouse/hamster laboratory diet, 10 mm pellets (Provimi Kliba, Switzerland), ad libitum, but no access during the exposures
- Water: tap water ad libitum, but no access during the exposures
- Acclimation period: at least 5 days

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


Administration / exposure

Route of administration:
inhalation
Type of inhalation exposure (if applicable):
whole body
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: whole body exposure system
- Method of holding animals in test chamber: the animals were kept singly in wire cages located in a glass-steele inhalation chamber, volume 1.4 m³
- System of generating particulates/aerosols: glass vaporizers with thermostat; continous infusion pumps

TEST ATMOSPHERE
- Brief description of analytical method used: total hydrocarbon analyzers were used to continuously monitor the constancy of concentrations of test substance vapors
- Samples taken from breathing zone: yes


Analytical verification of doses or concentrations:
yes
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1-2 females and 1 male
- Length of cohabitation: about 15.5 hrs
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
6 hrs per day
Frequency of treatment:
daily
Duration of test:
20 days (exposure period from day 6 post coitum to day 19 post coitum; 14 exposures)
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0.0046, 0.023, and 0.092 mg/L, corresponding to 1, 5 and 20 ppm
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
0.00438, 0.0228, and 0.0922 mg/L, corresponding to 0.95, 4.96, 20.0 ppm (mean values)
Basis:
analytical conc.
No. of animals per sex per dose:
25 mated female rats per test group
Control animals:
yes

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: No

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:
General state of health of the animals as well as a check for dead or moribund animalswas performed twice a day.
Clinical examinations were performed at least 3 times on exposure days and once during the day 0, preflow period and post-exposure observation day. During exposure only a group wise examination was performed.

BODY WEIGHT: Yes
- Time schedule for examinations:
at day 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20 post coitum, at the same time of the day

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
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: calculations of conception rate and pre- and postimplantation losses
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No
Statistics:
The Dunnet t test (two-sided) was performed for: body weight, body weight change, corrected body weight gain (net maternal body weight change), carcass weight, weight of unopened uterus, number of corpora lutea, number of implantations, number of resorptions, number of live fetuses, proportions of preimplantation loss, proportions of postimplantation loss, proportion of resorptions, proportions of live fetuses in each litter, litter mean fetal body weight, litter mean placental weight.
FISHER´S EXACT test (one-side) was performed for: female mortality, females pregnant at terminal sacrifice, number of litters with fetal findings.
WILCOXON-test (one-sided) was performed for: proportions of fetuses with malformations, variations and/or unclassified observations in each litter.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Details on maternal toxic effects:
1.) Clinical signs of toxicity: Overt signs of toxicity only were seen within the group of rats treated with 20 ppm of test substance(3 animals), and included salivation at the start of exposure, during and also after exposure (days 6 and 7) and urine smeared fur at the end of the study.
2.) Body weight: A delayed body weight development was observed within the group treated with 20 ppm on study days 8-20. At 5 ppm, the retarded body weight gain was transient. The corrected body weight gain was statistically significantly lower at 20 ppm and 5 ppm. Moreover, the carcass weight of the 20 ppm and the 5 ppm treatment groups were reduced.
3.) Necropsy: The uterus weights of the rats were not influenced by the test substance. Necropsy revealed no abnormalities due to the treatment. Diaphragmatic hernia occured as incidental in one dam of test group 2.
4.) Reproduction parameters: The conception rate, the mean number of corpora lutea, the implantation sites as well as the numbers of pre- and postimplantation losses, resorptions and viable fetuses were similar for all groups including the control.

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
4.38 other: mg/m3 air (analytical)
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Details on embryotoxic / teratogenic effects:
The examinations revealed no difference in the sex distribution between treated and control groups. The placental weights were similar for all groups. In contrast, the mean body weight of the fetuses within the group treated with 20 ppm of test substance was significantly reduced below the control value and was considered to be substance-related. The fetuses showed neither external nor soft tissue malformations. Skeletal malformations were observed at low incidences in all groups including control, but the significantly higher rate of incomplete ossification of supraoccipital or hyoid bones and wavy ribs observed within the highest treated group clearly indicates a substance-dependency.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
22.8 other: mg/m3 air (analytical)
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Mean maternal body weights during gestation (in g)

 

test group 0

test group 1

test group 2

test group 3

 

(0 mg/m3)

(4.6 mg/m3)

(23 mg/m3)

(92 mg/m3)

day 0

170.0

169.7

168.9

172.6

day 1

175.5

174.3

173.8

177.6

day 3

182.2

180.7

180.0

184.0

day 6

192.6

190.7

189.9

194.5

day 8

197.5

195.3

192.2

189.0*

day 10

205.3

203.7

200.3

194.6*

day 13

218.8

215.9

211.0

204.4**

day 15

227.4

224.9

218.6

212.3**

day 17

242.8

240.7

234.7

227.9*

day 19

261.1

259.4

254.3

246.2*

day 20

271.4

268.8

263.4

254.8*

Dunnett-test (two-sided)

*: p=0.05

** p=0.01

 

 

 

 

Mean maternal body weight change during gestation (in g)

 

test group 0

test group 1

test group 2

test group 3

 

(0 mg/m3)

(4.6 mg/m3)

(23 mg/m3)

(92 mg/m3)

days 0 to 6

22.6

21.0

20.9

21.9

days 6 to 19

68.5

68.6

64.4

51.7**

days 0 to 20

101.4

99.1

94.5

82.2**

Dunnett-test (two-sided)

** p=0.01

 

Mean fetal body weights (in g; on a litter basis)

 

test group 0

test group 1

test group 2

test group 3

 

(0 mg/m3)

(4.6 mg/m3)

(23 mg/m3)

(92 mg/m3)

of all viable fetuses

3,5

3,4

3,4

3,2**

of male fetuses

3,6

3,5

3,5

3,2**

of female fetuses

3,4

3,3

3,3

3,1**

Dunnett-test (two-sided)

** p=0.01

 

Applicant's summary and conclusion