Registration Dossier

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 1979-October 1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Similar to an OECD guideline study, but providing less data on findings. Performed according to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes (incl. certificate)
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Test Item: Cetylpyridinium Chloride
Data on file with owner company.

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
One-hundred sixteen sexually mature, virgin New Zealand SPF does and sixteen bucks were received from Charles River Breeding Laboratories, Wilmington, MA. Mass. Rabbits were weighed, ear-tagged, examined, and put in individual stainless steel cages. Does were housed in two rooms and bucks in a third. Rabbits were fed Purina Rabbit Chow and tap water ad libitum. Temperatures were from 20-25 degrees C with 45-55% humidity.. Lighting was controlled at 12 hours light and 12 hours dark, and ventilation underwent 10-15 fresh air changes per hour. The does were maintained for at least 18 days to allow any pseudo-pregnant does to become sexually receptive.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Dosing solutions were prepared daily with distilled water, and the concentrations of the test materials were calculated ont he basis of each animal receiving 2 ml of test solution per kg bw.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
not provided; on file with owner company
Details on mating procedure:
Due to a delay in characterizing the test material, dams were maintained for 65 days prior to breeding; the health of the animals was assessed and 6 does were excluded. The selected does were weighed and distributed into 7 groups of 15 does according to body weights. Bucks were trained to accept an artificial vagina. The use of sperm was distributed as evenly as possible among the groups of does in order to minimize genetic variability. The day of insemination was considered day 0 of gestation.
Duration of treatment / exposure:
Exposure and treatments lasted for a gestation period of day 7-18. However, some does were discontinued due to death or abortion of fetuses. The does were sacrificed on Day 29 of gestation.
Frequency of treatment:
once daily
Duration of test:
Days 7-18 of gestation
Doses / concentrations
Remarks:
Doses / Concentrations:
Groups 1-4, CPC only: 0, 2.5, 12, 100 mg/kg bw. Due to lethality, this was reduced to 25 mg/kg bw. Groups 5-7, CPC with DB: 2.5/0.28, 12/1.33, 100/11.8, reduced to 25/2.8.
Basis:
actual ingested
No. of animals per sex per dose:
15 females per dose

Control animals:
yes, plain diet
Details on study design:
Doses:
Group 1: 2 ml/kg distilled water (control group)
Group 2: 2.5 mg/kg CPC
Group 3: 12.0 mg/kg CPC
Group 4 100.0 mg/kg CPC
Group 5 2.5 mg/kg CPC + 0.28 mg/kg DB
Group 6 12.0 mg/kg CPC + 1.33 mg/kg DB
Group 7: 100.0 mg/kg CPC + 11.08 mg/kg DB

The day of insemination was considered Day 0 of gestation. Beginning on the day of insemination, the amount of feed consumed was recorded and the does were weighed every 3 days, and adjustments to the dose made. Beginning on day 7 and though day 18 of pregnanacy, except where the does died early, the does were given the daily treatments by gavage. Animals were sacrificed on day 29 of gestation.

Examinations

Maternal examinations:
The abdomen and thorax were opened and grossly examined. Histopathologic examinations occurred in animals which died during the dosing period.
Ovaries and uterine content:
Uterine horns were excised and the numbers and positions of live or dead fetuses and any resorption sites were noted and recorded.
Fetal examinations:
Fetuses were blotted dry of amniotic fluid, examined for gross abnormalities and weighed. The dead and aborted feuses that were not macerated were included in the gross examination and examined for soft-tissue abnormalities. All kits were tagged, identifying their number, the dam number, group and study numbers.

One-third of fetuses were selected to be eviscarated, cleared in alcoholic KOH and the skeletons stained with Alitarin Red Stain. They were examined for skeletal abnormalities. The remaining two-thirds were fixed in Bouins solution for 2-4 weeks, razor-blade sectioned and examined for soft-tissue abnormalities.
Statistics:
Mean +/- standard deviation. Standard methods as per Snedecor G and Cochran WG, 1967, Statistical Method, 6th Ed., Iowa State University Press, Ames, Iowa.
Indices:
not specifically presented. The number of corpora lutea were recorded.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Post mortem examinations of the dams which died after receiving 100 mg/kg bw/d indicated that the probable cause of death was from a severe disturbance of the gastrointestinal tract by the test materials, marked by severe diarrhea and gastric ulceration. Significantly decreased food consumption was produced in animals receiving 12 or 25 mg/kg bw; but there was no significant change in body weight in the 12 mg/kg bw group. Animals in the group given 25 mg/kg bw/d lost weight; those in the group receiving 25 mg CPC + 2.8 mg/kg DB gained very little weight. There were no statistically signifiant differences in the maternal weight gains during pregnancy.

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
12 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

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

Details on embryotoxic / teratogenic effects:
Six does aborted fetuses: one in the 2.5 mg/kg CPC group, two in the 12 mg/kg CPC group, two in the 25.0 mg/kg CPC group, and one in the 25.0 CPC + 2.8 DB mg/kg group.

There were no statistical differences with regard to the average numbers of corpora lutea or average numbers of resorptions, although the number of resorptions in the high dose group (25.0 mg/kg bw CPC) was higher than in that of controls.

There was a statistically significant decrease in the number of live fetuses in the group given 25.0 CPC + 2.8 mg/kg DB. While decreased, this was not significant in the group receiving 25.0 mg/kg CPC. The effect in the 25.0 CPC + 2.8 mg/kg DB group was related to the low number of implants.

Fetal weights in the 25.0 mg/kg CPC group were significantly lower in female fetuses compared to controls, but not among males. There were no statistical differences in the average number of either male or female fetus.

Statistical examination of the fetal abnormalities found during soft-tissue sectioning demonstrated no significant differences between the control and the CPC or CPC:DB treated groups. There were no statistical increases in the overall or individual incidences of skeletal abnormalities when compared to the control.

Two dams which survived after receiving 100 mg/kg CPC, and two dams surviving after receiving 100 mg/kg CPC + 2.8 mg/kg DB, had 19 or 18 fetuses (respectively) which were normal.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
> 25 mg/kg bw/day (actual dose received)
Based on:
test mat.
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

The full cohort of 15 dams in the high dose group did not receive 25 mg/kg bw/d; only 6 dams among the 15 which had not yet been treated with the test material. Therefore, the statistical power of the conclusion, at the high dose, is weaker than at lower doses.

Applicant's summary and conclusion

Conclusions:
CPC was examined in a teratology study in rabbits during gestation days 7-18, at doses of 2.5 to 100 mg/kg CPC, and in combination (9:1) with beta-phenoxyethyldimethyldodecyl ammonium bromide (DB). For CPC only, lethality was observed at the high dose of 100 mg/kg CPC. Of 6 rabbits not yet dosed from among the group of 15, the high dose was reduced to 25 mg/kg CPC. Maternal toxicity, as anorexia, loss of body weight and reduced food consumption, were observed at 12 and 25 mg/kg CPC. There was no teratogenic effects seen at any of the CPC levels tested. CPC is not teratogenic in rabbits at doses ranging up to ones that are embryotoxic and fatal to the dam.