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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:
2002-03-25 to 200211-07
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was carried out in accordance with an appropriate OECD test guideline and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Principles of method if other than guideline:
Method: other: OECD 422
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Canada, 188 LaSalle, St. Constant, Canada
- Age at study initiation: >=8 wk
- Weight at study initiation: 187-238 g (f); 250-313 g (m)
- Housing: 1/suspended wire cage
- Diet: standard diet ad libitum
- Water: drinking water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12 h/12 h

IN-LIFE DATES: From: 2002-03-25 To: 2002-11-07

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure (if applicable):
whole body
Vehicle:
unchanged (no vehicle)
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 450 l steel and glass Rochester-style inhalation chambers with stainless steel exposure caging.
- Method of holding animals in test chamber: individual stainless steel caged compartments
- Method of conditioning air: air passed through series of purification filters
- System of generating particulates/aerosols: TS placed in warming chamber (75 deg C). The liquid TS was then metered into a heated metal J-tube for vapourization.
- Air change rate: at 10 exchanges of chamber volume per h

TEST ATMOSPHERE
- Brief description of analytical method used: GC
- Samples taken from breathing zone: automatic sampling from chamber

Acclimatization for 3 h on 2 days
Analytical verification of doses or concentrations:
yes
Details on mating procedure:
- M/F ratio per cage: 1:1
- Length of cohabitation: continuously until evidence of copulation
- Proof of pregnancy: vaginal plug or sperm in vaginal smear (day 0)
Duration of treatment / exposure:
46 days for female and 28 days for male rats
Frequency of treatment:
6 hours/day; 7 days/week
Doses / concentrations
Remarks:
Doses / Concentrations:
100, 500, and 2500 ppm (nominal); 99, 512, and 2492 ppm (actual)
Basis:

No. of animals per sex per dose:
10
Control animals:
other: yes, control group was exposed to filtered air
Details on study design:
Sex: male/female
Duration of test: 46 days

Examinations

Maternal examinations:
Reproductive phase females: not examined at necropsy.
Ovaries and uterine content:
Reproductive phase females: number of corpora lutea and implantation sites recorded.
Fetal examinations:
Examination for gross external malformations only.
Statistics:
Statistical methods: Bartlett's test and Kolmogorov-Smirnov test. Parametric data was tested using one-way Analysis of Variance (ANOVA) followed by Dunnett's Test (if significant); nonparametric data was tested by Kruskal-Wallis Test followed by Wilcoxon. Categorical data and histomorphology findings were evaluated with Fisher's
Exact Test. Statistically significant probabilities are reported at either the p<0.05 or p<0.01 levels.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Effects on weight gain

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEC
Effect level:
500 ppm
Basis for effect level:
other: maternal toxicity
Dose descriptor:
LOAEC
Effect level:
2 500 ppm
Basis for effect level:
other: maternal toxicity
Dose descriptor:
LOAEC
Effect level:
2 500 ppm
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Embryotoxic: reduced litter size

Effect levels (fetuses)

Dose descriptor:
NOAEC
Effect level:
500 ppm
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

Reproductive/Developmental phase:
Decreased Litter Size/Implantation Sites: NOAEC = 500 ppm

 

Toxic Response/Effects by Dose Level:

2500 ppm
Females (Reproductive/Developmental Phase): Decreased litter size (33%*); Decreased litter weight (27%*); Decreased number of implantation sites (33%*)
Males exposed to 2500 ppm had decreased weight of seminal vesicles and
 atrophy.

 

Statistical Results, As Appropriate: "*" denotes statistically different from control (p<0.05).

The results can be summarized as follows:

Body weight: Reproductive/Developmental Phase Females: Decreased body weight (8%) on gestation day 20 at 2500 ppm

Food/water consumption: Reproductive/Developmental Phase Females: No treatment-related effect.

 

I. Description, severity, time of onset and duration of clinical signs:

Anogenital Staining: Reproductive/Developmental Phase: Present in 100 and 2500 ppm groups. Time of onset (first occurrence): study day 1. Duration (last noted occurrence): study day 34

Probable Porphyrin Staining: Reproductive/Developmental Phase: Present in 500 and 2500 ppm groups Time of onset (first occurrence): study day 4 Duration (last noted occurrence): study day 36. One isolated incident of a female rat in the 2500 ppm group was recorded where the rat was seen squealing and shaking with "bulging eyes" for 10 minutes during treatment on day 31.

 

II. Hematological findings incidence and severity: No treatment-related effects.

 

III. Mortality and time to death: All adult animals survived to their scheduled necropsy.  

 

IV. Gross pathology incidence and severity: No treatment-related macroscopic findings

 

V. Histopathology incidence and severity: Reproductive/Developmental Toxicity: Reduced litter size (33%), litter weight (27%), and number of implantation sites (33%) at 2500 ppm.



Applicant's summary and conclusion

Conclusions:
A well reported combined repeated dose/reproductive and developmental inhalation screening study, conducted according to the current guideline and in accordance with GLP, found no external abnormalities in the pups following the exposure to concentrations up to 2500 ppm (22.8 mg/L). Litter weight was decreased at this exposure (probably due to reduced litter size). One dam gave birth to 14 pups, none of which survived to PND 4. The NOAEC was determined to be 500 ppm (4.55 mg/l).