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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Reliability of 2 given since the data is based on read across, not the target substance.

Data source

Reference
Reference Type:
publication
Title:
Developmental Toxicity of Diethanolamine Applied Cutaneously to CD rats and New Zealand White Rabbits
Author:
Marty, M.Sue, Neeper-Bradley, Terri L., Neptun, D.A., Carney, Edward W.
Year:
1999
Bibliographic source:
Regulatory Toxicology and Pharmacology 30, 169-181 (1999)

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
no
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid - liquid: suspension

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Details on test animals and environmental conditions:
- Source: Charles River Laboratory (Portage, MI)
- Age at study initiation: 68-70 days
- Weight at study initiation: ca. 209 - 251 g
- Housing: individual in wire mesh cages
- Diet: Ground certified Rodent Diet (RMH 3200, agway, Inc, Waverly, NY) available ad libitum
- Water: Tap water ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 66-77
- Humidity (%): 40-70
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
dermal
Vehicle:
water
Details on exposure:
The test substance was dermally applied daily directly to the backs (clipped free of hair) of rats at a constant volume of 4 ml/kg/day. DEA remained in contact with the skin for 6 hours per day at doses of 0, 150, 500 or 1500 mg/kg bw/day from gestation day (GD) 6 through to 15. Following administration the dosing site was covered by sterilized gauze and then further occluded with polyvinyl fil attached to a specifically designed Lycra-Spandex jacket with velcro closures. Approximatley 6 hours after dosing, the jacket and gauze were removed, and the dosing site was wiped gently with gauze dampened with warm water and blotted dry.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Concentration and homogenicity of the DEA dosing solution was verified using a Hewlett-Packard 5880A gas chromatograph with a flame ionization detector. DEA concentrations ranged fro, 100.7 to 101.7% of the target. Rats in various dose groups did not receive the total volume of DEA during dosing on GD 12-15. There was a possible 10-25 % deficit in the expected doses delivered with the greatest difference seen in the 500 mg/kg bw/day dose group on GD 13.
Details on mating procedure:
Virgin female rats weighing between 209-251 g were mated overnight with male rats (one female:one male). Evidence of vaginal or dropped copulation plugs was considered a sign of successful mating and the day on which such evidence was found was designated as GD 0. Mated females were housed singly in stainless-steel wire-mesh cages.
Duration of treatment / exposure:
6 hours / day
Frequency of treatment:
Daily
Duration of test:
From GD 6-15 inclusive
No. of animals per sex per dose:
25 successfully mated females were assigned to each dose group
Control animals:
yes

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily for evidence of skin irritation and clinical signs during the dosing period and once daily during the post-treatment period

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: wice daily for evidence of skin irritation and clinical signs during the dosing period and once daily during the post-treatment period

BODY WEIGHT: Yes
- Time schedule for examinations: GD 0, 3, 6, 9, 12, 15, 18, 21 p.c.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21 (gross pathology)
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:

- Weight of uterus before it was opened
- Number of corpora lutea
- Number and distribution of implantation sites classified as :
• live fetuses
• dead implantations:
a) early resorptions - Uteri from females that appeared to be nongravi were placed in a 10% ammonium sulfide solution for detection of early resorptions (Salewski, 1964)



Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: No data
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter
Statistics:
Continuous variables were compared for homogenicity of variance using Levene's test for equal variance. Based on the outcome of this analysis, a parametric or non-parametric analysis of variance (ANOVA) was performed as appropriate. Significant results from parametric ANOVA anaysis, pooled T-tests were used for pairwise comparisons. Non-significant results from a non-parametric ANOVA analysis , separate variance T Tests for pairwise comparison were used.
The Kruskal-Wallis test, followed by the Mann-Whitney U test , where appropriate was used to statistically evaluate non-parametric data. Incidence data were compared using the Fisher's extract test. With the exception of frequency data for fetal malformations and variations, statistical analyses were performed using BMDP statistical software. For all statistical tests, the critical level of significance was set at 0.05 (two tailed).

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes. Remark: changes in weight gain, skin irritation, changes in liver weight, changes in blood parameters

Details on maternal toxic effects:
Rat dams administered 150 mg/kg/day DEA showed significant decreases in body weight gains at the end of the dosing period and during the post dosing period (GD 15-21). When corrected for gravid uterine weight, this corresponded to 4.5% decrease in body weight which is significantly less than body weights in control animals. At 150 and 500 mg/kg bw/day , there was no treatment related declines in maternal weight gain at any interval. No effect on food consumption was observed at any dose level. Following administration of DEA rats administered 150 and 1500 mg/kg bw/day had a significant increase in weight gain, although there was no evidence to show a clear dose response relationship.
Rats in the 500 and 1500 mg/kg bw/day group showed clinical signs of skin irritation which were dose dependent in incidence and severity. This condition persisted into the post treatment observation period in the high dose group. No significant effects on skin irritation were observed in the control group of 50 mg/kg bw/day group.
Analysis of blood samples collected at the time of necropsy showed that DEA slightly reduced red blood cell parameters , including haematocrit, MCV, MCH, haemoglobin concentration and erythrocyte number at all concentrations tested. Rats in th 1500 mg/kg bw/day group had increased numbers of leukocytes and lymphocytes, but decreased platelet numbers. Changes in red cell morphology (poikilocytosis, anisocytosis, polychromasia) were observed in all dose groups.
No changes in absolute or relative liver weights were observed in any dose group, but significant dose dependent increases in both absolute and relative kidney weights were observed at the 500 and 1500 mg/kg bw/day dose groups.
DEA had no effect on pregnancy rate, corpora lutea number, implantation number, litter size, resorption rate, number of dead foetuses, foetal body weight, foetal sex ratio or gravid uterine weight ant any dose level tested.

Effect levels (maternal animals)

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Dose descriptor:
LOAEL
Effect level:
150 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOEL
Effect level:
380 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects. Remark: Minor ossification effects that occurred only with significant maternal toxicity

Details on embryotoxic / teratogenic effects:
Dermal administration of DEA had no effect on the overall incidence of external, visceral or skeletal malformations or variations observed in rat foetuses. Litters fromthe 1500 mg/kg bw/day group had statistically significant increased incidences of six skeletal alterations poorly ossified cervical centrum, thoracic centrum , parietal, hindlimbs and forelimbs.The only statistical significant variation in the skull ar 1500 mg/kg was poorly ossified parietal. However, ossification patterns in adjacent bones suggest a general minor delay in ossification of the skull, There was no effect on any of these developmental parameters at 500 mg/kg bw/day.

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Dermally applied DEA did not produce any teratogenicity effects, even at doses which cause severe skin irritation. Increased incidences of six variation were seen at the high dose group. However, these effects were considered to involve minor delays in ossification which are thought to be reversible and not to have a long lasting effect on the health or survival of the offspring. A NOEL could not be identified for maternal toxicity due to haematological effects even at the low dose group. The maternal LOAEL was considered to be 150 mg/kg bw/day. The NOAEL for developemntal toxicity was considered to be 380 mg/kg bw/day instead of 500 mg/kg bw/day due to a dosing deficit on GD 12-15.
Executive summary:

Female CD rats were dermally exposed to DEA at concentrations of 0, 150, 500 or 1500 mg/kg bw/day from GD 6 to 15. Maternal toxicity included a 4.5 % decrease in body weight in animals in the 150 mg/kg bw/day group when compared with control animals, along with clinical signs of skin irritation in the mid and high dose group which were dose dependent in incidence and severity. Analysis of maternal blood samples collected at time of necropsy showed that DEA slightly reduced red blood cell parameters including haematocrit, MCV, MCH, haemoglobin concentrations and erythrocyte numbers in all dose groups. No changes in absolute or relative liver weights were observed in any dose group, but significant dose dependent increases in both absolute and relative kidney weights were observed at the 500 and 1500 mg/kg bw/day dose groups. DEA had no effect on pregnancy rate, corpora lutea number, implantation number, litter size, resorption rate, number of dead foetuses, foetal body weight, foetal sex ratio or gravid uterine weight at any dose level tested.

Repeated dermal administration of DEA had no effect on the overall incidence of external, visceral or skeletal malformations.Litters from the 1500 mg/kg bw/day group had statistically significant increased incidences of six skeletal alterations poorly ossified cervical centrum, thoracic centrum, and parietal, hind limbs and fore limbs. The only statistical significant variation in the skull at 1500 mg/kg was poorly ossified parietal. However, ossification patterns in adjacent bones suggest a general minor delay in ossification of the skull. There was no effect on any of these developmental parameters at 500 mg/kg bw/day.

Therefore, in conclusion dermally applied DEA did not produce any teratogenicity effects, even at doses which cause severe skin irritation. Increased incidences of six skeletal variations were seen at the high dose group. However, these effects were considered to involve minor delays in ossification which are thought to be reversible and not to have a long lasting effect on the health or survival of the offspring. A NOEL could not be identified for maternal toxicity due to haematological effects even at the low dose group. The maternal LOAEL was considered to be 150 mg/kg bw/day. The NOAEL for developmental toxicity was considered to be 380 mg/kg bw/day instead of 500 mg/kg bw/day due to a dosing deficit on GD 12-15.