Alkanes, C10-13, chloro

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28th October to 26th November 1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well conducted GLP study, similar to guideline

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1982

Report date:

1982

Reference 2

Reference Type:

publication

Title:

Summaries of toxicological data. Toxicology of chlorinated paraffins

Author:

Serrone DM, Birtley RDN, Weigand W and Millischer R

Year:

1987

Bibliographic source:

Fd Chem Toxicol. 25: 553-562

Reference 3

Reference Type:

secondary source

Title:

Unnamed

Year:

2000

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

Does not include peroid from implantation to start of organogenesis (days 1-5)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Alkanes, C10-13, chloro

EC Number:

287-476-5

EC Name:

Alkanes, C10-13, chloro

Cas Number:

85535-84-8

IUPAC Name:

Alkanes, C10-C13, Chloro

Details on test material:

- Name of test material (as cited in study report): short chain chlorinated paraffin (58% chlorination)
- Substance type: technical product
- Physical state: clear, slightly viscous liquid
- Analytical purity: "100%"
- Impurities (identity and concentrations): free hydrogen chloride (HCl) - 7ppm; no stabilisers
- Composition of test material, percentage of components: C10-13 chlorinated paraffin, 58% chlorination
- Purity test date: no data
- Lot/batch No.: R-201-198
- Expiration date of the lot/batch: "dependent on routine analysis"
- Stability under test conditions: "unstable"
- Storage condition of test material: -20oC

Test animals

Species:

rat

Strain:

other: COBS CD

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River breeding Labs, Portage, Michigan, USA
- Age at study initiation: approx. 12 weeks
- Weight at study initiation: 243 g on day 0 of gestation
- Fasting period before study: none
- Housing: singly in suspended wire-mesh cages
- Diet (e.g. ad libitum): Purina Certified Rodent Chow #5002, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 1980-10-28 To: 1980-11-26

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: Appropriate amount of chlorinated paraffin was weighed out, admixed with the vehicle and shaken by hand until homogeneous

VEHICLE
- Justification for use and choice of vehicle (if other than water): corn oil - test material solubility
- Concentration in vehicle: at a concentration to permit administration at a constant volume of 0.5 ml/100 g bw
- Amount of vehicle (if gavage): 0.5 ml/100 g bw
- Purity: no data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Weekly samples of dosing solutions taken prior to dosing and the concentration of chlorinated paraffin measured viscometrically by comparison with known standards.

Details on mating procedure:

- Impregnation procedure: co-housed
- If co-housed:
- M/F ratio per cage: 1 to 1
- Length of cohabitation: no data
- Proof of pregnancy: vaginal plug/vaginal smear for sperm referred to as day 0 of pregnancy
- Any other deviations from standard protocol: none

Duration of treatment / exposure:

days 6 to 19 of gestation

Frequency of treatment:

daily

Duration of test:

Animals sacrificed on day 20 of gestation

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 500 and 2000 mg/kg bw/day
Basis:
nominal conc.

No. of animals per sex per dose:

25 pregnant dams/dose group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: no data
- Rationale for animal assignment (if not random): sequential addition of mated females to the 4 dose groups

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily for mortality and overt changes in appearance/behaviour

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily for clinical signs of toxicity

BODY WEIGHT: Yes
- Time schedule for examinations: on gestation days 0, 6, 9, 12, 16 and 20

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20 (and animals which died before day 20)
- Organs examined: uterus and organs of the abdominal and thoracic cavities

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: location and numbers of viable and non-viable fetuses

Fetal examinations:

- External examinations: Yes; all per litter
- Soft tissue examinations: Yes; approx. half per litter
- Skeletal examinations: Yes; approx. half per litter

Statistics:

Male to female sex distribution and numbers of litters with malformations were compared using Chi square test with Yates' correction and/or Fisher's exact probability test.
The number of early and late resorptions and post-implantation losses were compared by the Mann-Whitney U-test
The mean number of viable foetuses, total implantations, corpera lutea and mean foetal body weights were compared by analysis of variance (one-way), Bartlett's test for homogeneity of variance and the appropriate t test

Indices:

no data

Historical control data:

Yes - vitamin A

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
No biologically meaningful differences in the appearance or behaviour of rats were seen in the 100 mg/kg bw/day group when compared to the controls. Yellow/brown staining/matting of anogenital region, soft stools, red/brown staining in nasal region, lethargy, oily coat, emaciation and excessive salivation was seen in animals in the 500 and 2000 mg/kg bw/day treatment groups. Mean body weight gain of top dose animals was reduced between days 9 and 16 of gestation and 8 top dose animals died between days 15 and 20 of gestation of unknown, but probably treatment-related effects.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
No biologically meaningful or statistically significant differences were seen, compared to controls, in the mean numbers of viable foetuses, early or late resorptions, postimplantation loss, total implantations, corpora lutea, the foetal sex distribution or malformations in the 100 and 500 mg/kg bw/day groups, genetic and developmental variations in all groups, or the mean foetal body weights in the 100 mg/kg bw/day group. The statistically significant increase in mean foetal weight in the 500 mg/kg bw/day group was not considered to be treatment-related. Decreased foetal viability per dam and increased postimplantation losses were noted in top dose animals. Adactyly and/or shortened digits were seen in 19 foetuses from 3/15 litters examined from top dose animals.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Treatment of pregnant rats with a C10-13 chlorinated paraffin (58% chlorination) by oral gavage from days 6 to 19 of gestation resulted in maternal toxicity at 500 and 2000 mg/kg bw/day (highest tested dose) and the appearance of foetal abnormalities at the top dose level only. No developmental effects were seen at 500 mg/kg bw/day and no adverse effects were seen in either dams or foetuses at 100 mg/kg bw/day.

Executive summary:

In a well conducted GLP study, similar to OECD Guideline 414, groups of 25 mated female COBS CD rats were given 0, 100, 500 or 2000 mg/kg bw/day of a C10 -12 chlorinated paraffin (58% chlorination) in corn oil by oral gavage on days 6 to 19 of gestation. Animal were killed on day 20 and the numbers and location of viable and non-viable foetuses, resorption sites and the total number of implantations and corpera lutea were determined. Appearance and body weight gain of dams was monitored and all foetuses were examined for external malformations. Approximately one half of the foetuses from each litter were examined for visceral malformations and the other half for skeletal abnormalities.

Clinical signs of maternal toxicity were seen in both 500 and 2000 mg/kg bw/day groups, comprising yellow or brown matting and staining of the coat in the anogenital region, red or brown staining in the nasal region, excessive salivation, lethary and emaciation. The effects were at an increased frequency in the top dose animals. A decrease in body weight gain from days 9 to 16 and 8/25 animals died between gestation days 16 and 20 in the top dose group. Significant increases in the numbers of post-implantation losses, due to both early and late resorptions, and a decrease in the numbers of viable foetuses was seen in the top dose group only. Foetal malformations (adactyly and/or shortened digits) were seen in 19 foetuses from 3/15 litters examined from the top dose animals.

Overall, no developmental toxicity was seen in animals in the 500 mg/kg bw/day group, and no adverse effects were seen in dams or foetuses in the control or 100 mg/kg bw/day groups. Therefore, the no-observed-adverse-effect level (NOAEL) for developmental toxicity in the rat in this study was 500 mg/kg bw/day.