Phenol, dodecyl-, branched, sulfurized

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1st to 25th February 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study following GLP. The reliability is reduced as the study is being used for read-across purposes.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OTS 798.4900 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Phenol, dodecyl-, sulfurized, carbonates, calcium salts, overbased.

IUPAC Name:

Phenol, dodecyl-, sulfurized, carbonates, calcium salts, overbased.

Constituent 2

Reference substance name:

122384-87-6

Cas Number:

122384-87-6

IUPAC Name:

122384-87-6

Details on test material:

122384-87-6/ 68784-26-9/122384-86-5/68784-25-8. Phenol, dodecyl-, sulfurized, carbonates, calcium salts, overbased.
Testing was performed on a commercial sample of this material. Typical purity of this material as distributed in commerce is 50% alkyl phenol sulfide and 50% highly refined lubricant base oil.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Portage, Michigan
- Age at study initiation: The animals were approximately eleven weeks old upon receipt.
- Weight at study initiation: The animals were weighed the day following receipt. Body weights ranged from 186 g to 242 g
- Housing: Upon arrival and until pairing, all animals were individually housed in clean, wire-mesh cages suspended above cage-board. The animals were paired for mating in the home cage of the male. Following positive identification of mating, the females were returned to an individual suspended wire-mesh cage.
- Diet (e.g. ad libitum): The basal diet used in this study was Purina® Certified Rodent Chow® #5002. This diet is a certified feed with appropriate analyses performed by the manufacturer and provided to WIL Research laboratories, Inc. No contaminants were present in animal feed or water at levels expected to interfere with the objectives of this study. Basal diet was provided ad libitum throughout the acclimation period and during the study.
- Water (e.g. ad libitum): Municipal water supplying the facility is sampled for contaminants according to Standard Operating Procedures. The results of these analyses are maintained at WIL Research Laboratories, Inc. Drinking water delivered by an automatic watering system.
- Acclimation period: 11 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): The temperature ranged from 67° to 75°F
- Humidity (%): relative humidity ranged from 20% to 49 %
- Air changes (per hr): Air handling units were set to provide approximately 10 fresh air changes per hour.
- Photoperiod (hrs dark / hrs light): 12-hour light/12-hour dark

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

peanut oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
An appropriate amount of the test material was drawn into a syringe for each group. A sufficient amount of the vehicle, peanut oil, was added to a properly-labeled storage container. The test material was slowly added to the vehicle while being mixed on a Polytron® PT6000 until all of the test material was incorporated into the vehicle. The mixtures were stirred using a magnetic stir bar and plate throughout sampling, dispensation, dosing and periods of non-use.
Preparations for all dose groups were formulated three times (January 11 and February 7 and 14, 1994). The preparations were stored at room temperature, protected from light. The formulated suspensions were visually inspected for homogeneity by the Study Director prior to the initiation of dosing and were found to be acceptable for administration.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dosing solutions in peanut oil vehicle were prepared three times over a period of about a month, and their concentration, homogeneity and stability were verified by chemical analysis.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused: The animals were paired for mating in the home cage of the male.
- M/F ratio per cage: The animals were paired on a 1:1 basis.
- Proof of pregnancy: Positive evidence of mating was confirmed by the presence of a copulatory plug or the presence of sperm in a vaginal smear. Each mating pair was examined daily. The day on which evidence of mating was identified was termed day 0 of gestation and the animals were separated.

Duration of treatment / exposure:

Exposure period was gestation days 6 through 15. For the control, 25 mated females received peanut oil vehicle only.
A dosage volume of 5 ml/kg was used for all dosage levels.

Frequency of treatment:

daily

Duration of test:

Dams euthanized for uterine examinations and collection of fetuses on gestation day 20.

No. of animals per sex per dose:

25 females per dose

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: All rats were observed twice daily for moribundity and mortality. Animals were also observed for signs of toxicity approximately one hour following treatment throughout the dosing period.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Detailed clinical observations were recorded individually from days 0 through 20 of gestation.

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

FOOD CONSUMPTION: Yes
Individual food consumption was recorded on gestation days 0, 6-16 (daily) and 20. Food intake was reported as g/animal/day and g/kg/day for each corresponding body weight change interval.

POST-MORTEM EXAMINATIONS: Yes
- All maternal animals were euthanized by carbon dioxide inhalation on gestation day 20.
- Organs examined:
The thoracic, abdominal and pelvic cavities were opened by a ventral mid-line incision and the contents were examined. In all instances, the post mortem fmdings were correlated with the ante mortem comments and any abnormalities were recorded.

Ovaries and uterine content:

The uterus and ovaries were excised and the number of corpora lutea on each ovary was recorded. The trimmed uterus was weighed, opened and the number and location of all fetuses, early and late resorptions and the total number of implantation sites were recorded. The individual uterine distribution of implantation sites was documented using the following procedure. All implantation sites, including resorptions, were numbered in consecutive order beginning with the left distal to the left proximal uterine horn, noting the position of the cervix, and continuing from the right proximal to the right distal uterine horn. Maternal tissues were preserved in 10% neutral buffered formalin for possible future histopathological examination only as indicated by the gross findings. The carcass of each dam was then discarded.

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: all per litter
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: half per litter

Statistics:

Body and uterine weights, food consumption, corpora lutea, total implantations and viable fetuses were analyzed by ANOVA with a Dunnett’s
post-hoc test. Fetal sex ratios were analyzed with the Chi-square test with Yate’s correction factor. Resorptions, post-implantation losses, and dead fetuses were analyzed with the Mann-Whitney U-test. Litter proportions of intrauterine data were analyzed with the Kruskal-Wallis test. Fetal
malformations and variations were analyzed with Fisher’s Exact test. Mean litter proportions of malformations and variations were analyzed with the Mann-Whitney U-test.

Historical control data:

Yes

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Decreased mean body weight gain during the dosing period (from gestation days 6 to 10-16) at 1000 mg/kg b.wt./day. No maternal body weight
effects at 300 mg/kg b.wt./day

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

2

Key result

Dose descriptor:

NOAEL

Effect level:

300 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:yes

Details on embryotoxic / teratogenic effects:
The number of litters with fetuses having skeletal variation (bent ribs) was increased at 1000 mg/kg b.wt./day. This and other fetal variations were
not increased at 300 mg/kg b.wt./day. Therefore the developmental toxicity NOEL was 300 mg/kg/bw/day.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

skeletal malformations

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Statistical results:

Mean body weight gains during the dosing period (from gestation days 6 to 10-16) of the high-dose group were significantly (p<0.01) lower than controls. The number of high-dose litters with fetuses having bent ribs was significantly higher (p<0.05) than the control group. All other statistically significant differences were not of toxicological significance.

Result observations:

Mating success was variable among groups. The number of gravid females/group was 25, 22, 24 and 21 for control, low-, middle- and high-dose groups, respectively. There were no abortions.

Survival: All dams survived to scheduled termination.

Clinical observations: Material and/or staining around the mouth of about half of the high dose animals were the only treatment-related signs and were seen only at the 1-hour post-dose observation time. Onset of these signs usually occurred within 5-7 days after initiation of dosing and signs persisted until the end of the exposure period.

Body weights: There were sporadic and transient differences in mean body weights between treatment groups and controls, due to variation in the number of gravid females/group and differences in day 0 means. Body weight gain, however, in the high-dose group was about 17% lower than controls only during the exposure period, starting on day 10 and persisting until day 16.

Food consumption: There was no effect on food consumption on a g/kg b.wt./day basis.

Gravid uterine weights: There were no significant differences of mean gravid uterine weights.

Maternal gross pathology: No dose-related gross pathology was observed.

Ovarian/intrauterine observations: Embryonic and fetal growth, development and survival were not affected by test material administration. Pre- and post-implantation loss, early and late resorptions, viable and dead fetuses were not affected by treatment when evaluated as litter means or as mean litter proportions. Likewise, sex ratio and weight of fetuses were not affected by treatment. Mean number of viable fetuses ranged from 15.9-17.3 per litter.

Fetal malformations: Malformations were found in 3 fetuses from different litters. These consisted of 2 fetuses from the mid-dose group, one with exencephaly, malpositioned testes and costal cartilage anomaly and the other with hydrocephaly. The third malformed fetus was from the high-dose group and had a single malformation, meningocele. The occurrence and incidence of these malformations was within the range of laboratory historical controls. These malformations are, therefore, considered to be of spontaneous origin.

Fetal variations: The number of litters in the high-dose group with fetuses having bent ribs was significantly higher than the control group. This skeletal variation was not found with elevated frequency in the low- or mid-dose groups. No other treatment related skeletal variations were observed.

Applicant's summary and conclusion

Conclusions:

Based on the results of this study, the NOAEL (no observable adverse effect level) for maternal and developmental toxicity was considered to be 300 mg/kg/day.

Executive summary:

The potential maternal and developmental toxicity of the test material was evaluated in the rat by a study conducted to OECD Guideline 414 conducted in accordance with GLP.

The potential maternal and developmental toxicity of the test material was evaluated in the rat. The test material in peanut oil was administered orally by gavage to three groups of 25 bred Sprague-Dawley Crl:CD®BR female rats once daily from gestation days 6 through 15. Dosage levels were 50, 300 and 1000 mg/kg/day administered at a dose volume of 5 m1/kg. A concurrent control group (25 bred females) received the vehicle, peanut oil, on a comparable regimen at 5 ml/kg. All rats were observed twice daily for appearance and behavior. Body weights and food consumption were recorded at appropriate intervals. A laparohysterectomy was performed on all animals on gestation day 20. The uteri and ovaries were examined and the numbers of fetuses, early and late resorptions, total implantations and corpora lutea were recorded. Mean gravid uterine weights and net body weight changes were calculated for each group. The fetuses were weighed, sexed and examined for external, soft tissue and skeletal malformations and developmental variations.

All maternal animals survived to the scheduled necropsy on gestation day 20. Treatment-related clinical signs were noted one hour following dosing in the 1000 mg/kg/day group and consisted of red, clear, yellow and/or tan staining/matting/material around the nose and mouth. Mean body weight gains in the 1000 mg/kg/day group were significantly reduced for gestation days 6-10, 6-11, 6-12, 6-13, 6-14, 6-15 and 6-16. Mean food consumption in the 50, 300 and 1000 mg/kg/day groups was unaffected by test article administration. No treatment-related necropsy fmdings were noted at any dose level on gestation day 20.

Intrauterine growth and survival were unaffected by treatment at dose levels of 50, 300 and 1000 mg/kg/day. The malformations observed in this study were considered to be spontaneous in origin. A significantly increased incidence of one fetal developmental variant, bent ribs, was observed at the 1000 mg/kg/day dose level.

In conclusion, maternal toxicity (reduced body weight gain) was observed at the 1000 mg/kg/day dose level. No maternal toxicity was apparent at the 50 and 300 mg/kg/day dose levels. Developmental toxicity was apparent at a dose level of 1000 mg/kg/day by an increased incidence of the skeletal variant bent ribs. No developmental toxicity was observed at dose levels of 50 and 300 mg/kg/day. Based on the results of this study, the NOAEL (no observable adverse effect level) for maternal and developmental toxicity was considered to be 300 mg/kg/day.

The study is being used as read across to a structurally similar substance.