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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:
18 July 1984 - 15 August 1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was performed under GLP and according to a method similar to currently internationally accepted guidelines. No verification of dose levels, and no information on food consumption. Exposure from implantation (day 6) through day 15 of gestation instead of from implantation until one day prior to the day of scheduled kill (day 19). Gravid uterus weight was not determined.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Principles of method if other than guideline:
Performed in accordance with Series 83-3 of the Environmental Protection Agency Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, issued November, 1982.
Devations:
- Gravid uterus weight was not determined.
- No verification of dose levels
- No information on food consumption.
- Exposure from implantation (day 6) through day 15 of gestation instead of from implantation until one day prior to the day of scheduled kill (day 19).
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Name: Santicizer® 9C
Batch No.: QD 5087 Packer 2503545
Appearance: White powder

The study was conducted on Santicizer® 9C (a mixture of 32% o-TSA and 68% p-TSA), > 99% purity.

Test animals

Species:
rat
Strain:
other: COBS CD
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Portage, Michigan, USA
- Age at study initiation: 70 days
- Weight at study initiation: The rats were 118 days old at the time of mating and weighed between 255 and 346g on gestation day 0.
- Fasting period before study: Not applicable
- Housing: The rats were housed individually in suspended wire-mesh cages from receipt until sacrifice except during mating when one male and one female were placed together.
- Diet (e.g. ad libitum): ad libitum, basal Laboratory diet of Purina Certified Rodent Chow #5002
- Water (e.g. ad libitum): ad libitum, tap water
- Acclimation period: 48 day acclimation period


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22.2 ± 0.35
- Humidity (%): 67 ± 13.4
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12


IN-LIFE DATES: 18 July 1984 - 15 August 1985

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
The appropriate amount of Santicizer 9 for each group was ground daily with a mortar and pestle, weighed, and suspended i n the vehicle, Mazola corn oil, using a tissue homogenizer. The test material suspension was then transferred to a graduated mixing cylinder and additional vehicle added to yield a sufficient volume of prepared test material.
The suspension was shaken by hand and dispensed into a capped container. Prior to administration, the suspension was stirred using a magnetic stit
bar and stir plate.

VEHICLE
- Justification for use and choice of vehicle (if other than water): no data
- Concentration in vehicle: The test article was prepared at concentrations to permit the administration of dosage levels of 50, 250 and 500 mg/kg/dap at a dosage volume of 10 ml/kg. Individual dosages were determined from individual body weights recorded on gestation days 6, 9 and 12.
- Amount of vehicle (if gavage): max. 10 ml/kg.
- Lot/batch no. (if required): no data
- Purity: no data
Analytical verification of doses or concentrations:
no
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1
- Length of cohabitation: no data
- After "no data" days of unsuccessful pairing replacement of first male by another male with proven fertility.
- Further matings after two unsuccessful attempts: no data
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- Any other deviations from standard protocol: none
Duration of treatment / exposure:
single daily dose on days 6 through 15 of gestation
Frequency of treatment:
Single daily dose
Duration of test:
Days 6 through 15 of gestation
Doses / concentrations
Remarks:
Doses / Concentrations:
50, 250, 500 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
25
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: range finding study. For summary see "1333-07-9, Developmental toxicity / teratogenicity, Leng, 1985, RS"

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Prior to treatment, the females were observed twice daily for mortality and overt changes in appearance and behavior. They were
observed twice daily for mortality.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily on days 6 through 15 of gestation.

BODY WEIGHT: Yes
- Time schedule for examinations: Individual maternal body weights were recorded on gestation days 0, 6, 9, 12, 16 and 20.


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: The abdominal and thoracic cavities and organs of the dams wesere examined for grossly evident morphological changes and the carcasses discarded. Maternal tissues vere preserved in 10% neutral buffered formalin for possible histopathological examination as deemed necessary by the gross findings.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: The number and location of viable and nonviable fetuses, uteri from females that appeared nongravid uere opened and placed in 10% anmonium sulfide solution for detection of implantations.
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litte
- Head examinations: No: included in soft tissue examination, only applicable for non-rodents
Statistics:
All statistical analyses compared the treatment groups with the control group, with the level of significance at P<0.05 and p<0.01. All means were accompanied by standard deviations. Male to female fetal sex ratios and the proportions of litters with malformations were compared using the Chi-square test criterion with Yates' correction for 2 x 2 contingency tables and/or Fisher's exact probability test as described by siegel to judge significance of differences.
The proportions of resorbed and dead fetuses and postimplantation losses were compared by the Mann-Whitney U-test as described by Siegel and Weil to judge significance of differences.
Mean numbers of corpora lutea, total implantations, live fetuses, mean fetal body weights, and mean maternal body weights and body weight changes were compared by analysis of variance (one-way classification). Barelett's test for homogeneity of variances and the appropriate t-test (for equal or unequal variances) as described by Steel and Torrie using Dunnet t 's multiple comparison tables to judge significance of differences.
Historical control data:
Included in the study

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Survival was 100% among the control, 50, 250 and 500 mg/kg/day groups. The test article did not produce meaningful differences in maternal appearance and behavior at any dosage level. There was no test item related effect on pregnancy rate.
Clinical signs observed in some groups inclusive of the control, included the following : alopecia .and scabbing, sparse haircoat,
and malligned upper incisors with associated ocular discharge.
The following gross changes were noted during necropsy in the treated and control groups: hydronephrosis with or without distended ureters, misshapen kidney, distended uterus and cervix, and adherence of the liver to the kidney.
The test article had a marked inhibitory effect on maternal body weight gain at 250 and 500 mg/kg/day during the overall treatment interval.Moreover, marked reductions in gain were evident at 500 mg/kg/day during the overall gestation interval. Weight loss was observed during the gestation day 6 to 9 subinterval for both groups. All of these decreases were statistically significant. No similar effect was observed at 50 mg/kg/day.
An increase in postimplantation loss was noted for the 250 and 500 mg/kg/day groups, relative to the control. The increase was statistically significant at 500 mg/kg/day. The test article had no effect on the i.e., corpora lutea, total implantations, viable litter size, and sex Distribution, at 500 mg/kg/day and less.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
50 mg/kg bw/day (actual dose received)
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Effect level:
50 mg/kg bw/day (actual dose received)
Basis for effect level:
other: developmental toxicity

Results (fetuses)

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

Details on embryotoxic / teratogenic effects:
A treatment-related trend of fetal body weight inhibition was observed at all dosage levels. Fetal body weights were statistically significantly less than the control at 250 and 500 mg/kg/day. Weight inhibition, although very slight and not statistically significant, was also observed at 50 mg/kg/day and was deemed compound related as it was considered part of the trend observed at higher dosage levels.
The incidence of fetal malformations occurring in the treated groups was not meaningfully different from the control. A single instance each of a tail anomaly with anal atresia, and a vertebral anomaly occurred in a 250 mg/kg/day litter. Also, one 500 mg/kg/day fetus exhibited a retroesophageal aortic arch. No malformations occurred in the control and 50 mg/kg/day animals.
With respect to developmental variations, the number of litters exhibiting unossification of sternebrae #5 and/or #6 was increased exclusively at 500 mg/kg/day relative to the control. The remaining variations were noted in the control and treated groups at similar incidence or occurred as an isolated incidence and were deemed biologically irrelevant.

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Based on these results, o/p-TSA did not produce a teratogenic effect when administered orally to mated Charles River COBS CD rats at 500 mg/kg/day and less.
Executive summary:

A study was performed under GLP and according to a method similar to currently internationally accepted guidelines. Performed in accordance with Series 83-3 of the Environmental Protection Agency Pesticide Assessment Guidelines, Subdivision F, Hazard Evaluation: Human and Domestic Animals, issued November, 1982. Mated Charles River COBS CD rats consecutively assigned to one control and three treatment groups of 25 animals each were used to determine the teratogenic potential of Santicizer 9. Dosage levels of 50, 250 and 500 mg/kg/day were administered orally by gavage as a single daily dose on days 6 through 15 of gestation at a constant volume of 10 ml/kg. The control group received the vehicle only, corn oil, on a comparable regimen. Cesarean sections were performed on all surviving females on gestation day 20 and the fetuses were removed for teratologic evaluation.

Survival was 100% among all groups on study. Santicizer 9 produced meaningful changes in maternal body weight gain and several Cesarean section parameters when administered at 250 and 500 mg/kg/day. Maternal weight loss was evident during a portion of the treatment interval at 250 and 500 mg/kg/day and both groups exhibited significant (p<0.01) reductions in weight gain during the overall treatment period. Statistically significant reductions were also noted at 500 mg/kg/day during the overall gestation period. Fetotoxicity was apparent at 250 and 500 mg/kg/day as evidenced by increased postimplantation loss which was statistically significant at 500 mg/kg/day. In addition, a treatment-related trend of fetal body weight inhibition was noted at all dosage levels and values were significantly different from the control, p<0.01 at 250 and 500 mg/kg/day. An increase in the number of litters exhibiting unossification of sternebrae #5 and/or #6 was noted exclusively at 500 mg/kg/day and was correlated with fetal body weight reduction. Maternal appearance and behavior and the incidence of fetal malformations were not affected at any dosage level. Based on these results, Santicizer 9 did not produce a teratogenic effect when administered orally to mated Charles River COBS CD rats at 500 mg/kg/day and less.