Isotridecan-1-ol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

Principles of method if other than guideline:

OECD Guidelines for Testing of Chemicals; Proposal for updating Guideline 414: Prenatal Developmental Toxicity Study (January 22, 2001)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

EC Number:

607-896-8

Details on test material:

- Name of test material (as cited in study report): Tridecanol H
- Physical state: Liquid / colorless - clear
- Analytical purity: > 99 w%
- Lot/batch No.: EVD 55712
- Test substance No.: 03/0197-1
- pH-value: about 5-6
- Homogeneity: The test substance was homogeneous by visual inspection.
- Stability: The stability under storage conditions was confirmed by reanalysis
- Storage condition of test material: Room temperature, exclusion of oxygen (storage under nitrogen)

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Germany
- Age at study initiation: The animals were supplied at an age of about 70 - 84 days.
- Weight at study initiation: Based on the pregnant animals the body weight on day 0 varied between 146.2 - 188.1 g.
- Housing: single housing
- Diet: ground Kliba maintenance diet rat/mouse/hamster meal, supplied by PROVIMI KLIBA SA, Kaiseraugst, Switzerland; food was available to the animals ad libitum throughout the study (from the day of supply to the day of necropsy);
- Water: drinking water of tap water quality from water bottles; ad libitum
- Acclimation period: Between start of the study (beginning of the experimental phase) and first administration (day 6 p.c.) the animals were acclimated to the laboratory conditions.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: olive oil Ph. Eur./DAB

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

The oily test substance solutions were prepared at the beginning of the administration period and thereafter at intervals, which took into account the analytical results of the stability verification. For the preparation of the solutions, an appropriate amount of the test substance was weighed in a graduated measuring flask depending on the dose group, topped up with olive oil Ph.Eur./DAB and subsequently thoroughly mixed.

Administered standard dose volume of 5 ml/kg body weight

VEHICLE
- Concentration in vehicle: 1.2, 5 or 15 g/100 ml

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The test substance solutions were analyzed by GC. The results of the analyses of test substance solutions in olive oil Ph.Eur./DAB confirmed the correctness of the prepared concentrations. The analytical values of the samples corresponded to the expected values within the limits of the analytical method, i.e. were always above 90% and below 110% of the nominal concentrations.

Details on mating procedure:

The animals were mated by the breeder ("time- mated") and supplied on day 0 post coitum (p.c.). The animals arrived on the same day (i.e. day 0 p.c.) at the experimental laboratory. The following day was designed "day 1" p.c..

- Proof of pregnancy: vaginal plug / sperm referred to as day 0 p.c.

Duration of treatment / exposure:

day 6 through day 19 of gestation (from implantation to one day prior to the expected day of parturition)

Frequency of treatment:

1x/d

Duration of test:

on day 6 through day 19 post coitum (p.c.)

Doses / concentrations

Remarks:

Doses / Concentrations:
60, 250, 750 mg/kg bw

No. of animals per sex per dose:

25 mated female Wistar rats/group

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: A check was made twice a day on working days or once a day (Saturday, Sunday or on public holidays) (days 0 - 20 p.c.). The animals were examined for clinical symptoms at least once a day, or more often when clinical signs of toxicity were elicited (days 0 - 20 p .c.).

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed on days 0, 1, 3, 6, 8,10,13, 15, 17, 19 and 20 p.c.. The body weight change of the animals was calculated from these results. Furthermore, the corrected body weight gain was calculated after terminal sacrifice (terminal body weight on day 20 p .c. minus weight of the unopened uterus minus body weight on day 6 p .c.).

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes (With the exception of day 0, the consumption of food was determined on the same days as was body weight.)
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes / No / No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: liver, uterus, and ovaries

OTHER:

Clinical Pathology:
Blood was taken from the retroorbital venous plexus in the morning from fasted animals. The animals were anaesthetized using isoflurane as anesthesia. The blood sampling procedure and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. The following examinations were carried out in all female animals per test group:

Hematology:
The following parameters were determined in blood with EDTA-K3 as anticoagulant using a particle counter (ADVIA 120 model; Bayer, Fernwald, Germany): leukocytes, erythrocytes, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, differential blood count, reticulocytes.

Furthermore, differential blood smears were prepared and stained without being evaluated.

The clotting analyses were carried out and the prothrombin time (Hepator Quick's test) was determined.

Clinical chemistry:
An automatic analyzer was used to examine the clinicochemical parameters. The following parameters were determined: alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, serum-gamma-gIutamyltransferase, sodium, potassium, chloride, inorganic phosphate, calcium, urea, creatinine, glucose, total bilirubin, total protein, albumin, globulins, triglycerides, cholesterol, magnesium

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: dead fetuses

Fetal examinations:

- External examinations: Yes [all per litter]
- Soft tissue examinations: Yes: [half per litter]
- Skeletal examinations: Yes: [half per litter]
- Head examinations: Yes: No data

Statistics:

STATISTICS
Statistics of clinical, necropsy and fetal examinations:
Simultaneous comparison of all dose groups with the control group using the DUNNETT-test (two sided) for the hypothesis of equal means: Food consumption, body weight, body weight change, corrected body weight gain (net maternal body weight change), carcass weight, weight of unopened uterus, number corpora lutea, number of implantations, number of resorptions, number of live fetuses, proportions of preimplantation loss, proportions of postimplantation loss, proportions of resorptions, proportion of live fetuses in each litter, litter mean fetal body weight, litter mean placental weight.
Organ weights (liver, kidneys, spleen): Non-parametric one way analysis using KRUSKAL-WALLIS- test (two-sided). If the resulting p-value was equal or less than 0.05, a pairwise comparison of each dose group with the control group was performed using the WILCOXON-test (two-sided) for the equal medians.
Pairwise comparison of each dose group with the control group using Fishers exact test (one-sided) for the hypothesis of equal proportions: Female mortality, females pregnant at terminal sacrifice, number of litters with fetal findings;
Pairwise comparison of each dose group with the control group using the Wilcoxon-test (one-sided) for the hypothesis of equal medians: Propotions of fetuses with malformations, variations and/or unclassified observations in each litter.

Statistics of clinical pathology:
Means and standard deviations of each test group were calculated for several parameters.
Clinical pathology except reticulocytes and differential blood count. Non-parametric one way analysis using KRUSKAL-WALLIS test (two sided). If the resulting p-value was equal or less than 0.05, a pair wise comparison of each dose group with the control group was performed using Wilcoxon-te t (two-sided) for the equal medians.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes. Remark: (at 750 mg/kg body weight/day)

Details on maternal toxic effects:
Mortality:
There were no substance-related or spontaneous mortalities in any of the groups.

Clinical symptoms:
All high dose (750 mg/kg body weight/day) and the majority (17 out of 25) of the mid dose (250 mg/kg body weight/day) animals showed transient salivation immediately after treatment on one or several days of the treatment period; however, the observed salivation persisted in the respective females only for a few minutes after the actual gavaging had taken place. This substance-induced symptom was observed first for high dose females Nos. 98, 99 and 100 on day 7 p.c. and for mid dose rat No. 75 on day 12 p.c.. After cessation of treatment on day 19 p.c., salivation did not occur any longer.
The observed temporary salivation of the animals is considered to be substance-induced. It is very likely, that this finding was induced by bad taste of the test substance or local affection of the upper digestive tract. Salivation itself is not assessed as an adverse or toxic effect.

Additionally, 4 high dose dams (Nos. 77, 83, 98 and 100) showed urine-smeared fur on gestation days 10 - 13 or 17 - 20. This clinical finding is a sign of discomfort of the rats and is probably substance-induced.

No indications for disturbances of the general behavior, however, occurred in the dams of test groups 0 and 1 (0 and 60 mg/kg body weight/day).

Food consumption:
The mean food consumption of the high dose dams (750 mg/kg body weight/day) was statistically significantly reduced (up to about 11 % below the concurrent control value) on treatment days 6 - 10 p.c.. Thereafter, food consumption of the top dose rats was similar to control values and was not influenced in a dose-related manner.
The food consumption of the females of test groups 1 and 2 (60 and 250 mg/kg body weight/day) was unaffected and did not show any statistically significant or biologically relevant differences in comparison to the controls.
The transient reduction in food consumption of the high dose dams at initiation of dosing is considered to be substance-induced; however, the decreased food intake had no corroborative effects on body weight data and corrected body weight gain of these females.

Body weight data:
There were no statistically significant or biologically relevant differences between the controls and the substance-treated dams in terms of body weights and body weight gain during the study. The observed slight and transient, but statistically significant reductions in food consumption at 750 mg/kg on the first treatment days induced no adverse effects on body weight development of these dams.

Corrected body weight gain (net maternal body weight change):
The corrected body weight gains (terminal body weight on day 20 p.c. minus weight of the unopened uterus minus body weight on day 6 p.c.) of the dams of test groups 1 - 3 (60; 250 and 750 mg/kg body weight/day) revealed no differences of any biological relevance to the corresponding control group. Moreover, a clear relation to dosing was not present.

Examinations of the dams at termination:
--------------------------------------
Hematology:
There were no treatment- related changes in the hematological parameters measured.

Clinical chemistry:
At the end of the administration period serum enzyme examinations revealed slightly, but statistically significantly increased alanine aminotransferase activities in the high dose animals. The other serum enzymes were not affected by the test compound.
Blood chemistry investigations showed decreased total protein and globulin concentrations and increased triglyceride levels in the serum of the high dose females. No treatment- related changes were observed in the other blood chemistry parameters.
The slight changes seen in the clinical chemistry parameters alanine aminotransferase, total protein, globulins and triglycerides of the high dose animals are considered to be test substance-related and are indicative for a mild adverse effect on the liver.

Other deviations:
There are additional statistically significant intergroup differences in the results of clinical pathology testing. These deviations are marginal, incidental, or lack dose-response relationship. Accordingly, these findings are considered to be of no toxicological significance.

Uterus weight:
The mean gravid uterus weights of the animals of test groups 1 - 3 (60, 250 or 750 mg/kg body weight/day) were not influenced by the administration of the test substance. The differences between these groups and the control group revealed no dose-dependency and were assessed to be without biological relevance.

Liver weight:
Absolute and relative mean liver weights were statistically significantly increased at the high dose group (750 mg/kg body weight/day) and were about 14% (absolute) or 18% (relative) above control values. The increased liver weights at the top dose are in line with the slight changes seen in different clinical chemistry parameters (i.e. alanine aminotransferase, total protein, globulins and triglycerides); they are considered as substance-induced.
Absolute and relative liver weights of the dams of test groups 1 and 2 (60 and 250 mg/kg body weight/day) were similar to the respective control values and did not show any toxicologically significant changes.

Kidney weights:
Absolute and relative mean kidney weights of the dams of test groups 1, 2, and 3 (60, 250 and 750 mg/kg body weight/day) were similar to the respective control values and did not show any toxicologically significant differences.

Spleen weight:
Absolute mean spleen weights were statistically significantly decreased at the high dose group (750 mg/kg body weight/day) and were about 9% lower than the control values. As the more important relative spleen weights of the top dose dams remained unaffected, this is considered to be spontaneous in nature and not as substance-induced .
The absolute and relative spleen weights of the low and mid dose rats (60 and 250 mg/kg body weight/day) were similar to the respective control values and did not show any toxicologically significant changes.

Necropsy findings:
There were no substance-related observations at necropsy in any of the dams.
Control dam (No. 10) had a hemorrhagic thymus. This gross finding is considered to be spontaneous in nature and is probably related to the method how the rats were killed.

Reproduction data of dams:
--------------------------
The conception rate reached 100% in test groups 0 and 1 (0 and 60 mg/kg body weight/day), 92% in test group 2 (250 mg/kg body weight/day) and 96% in test group 3 (750 mg/kg body weight/day). As all rats that became pregnant had implantation sites at necropsy, a sufficient number of females for the purpose of the study were available.
There were no substance-related and/or biologically relevant differences between the different test groups in conception rate, in the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation losses, the number of resorptions and viable fetuses.
Low dose dam No. 34 had one dead fetus, but also 9 live fetuses in the uterus. Mid dose dam No. 62 was only pregnant by stain. It had only two very early resorptions, but no viable fetuses in the uterus. The isolated occurrence of one low dose rat with one dead fetus and of one mid dose female with total resorptions does not suggest any relation to treatment. Moreover, both findings occur also occasionally as spontaneous findings in the strain of rats used for this study.
Thus, all differences observed in respect to the gestational parameters in the various test groups were within the normal range of deviations for animals of this strain and age.

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day

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:
Examinations of the fetuses after dissection from the uterus:

Sex distribution of fetuses:
The sex distribution of the fetuses in test groups 1 - 3 (60, 250 and 750 mg/kg body weight/day) was comparable with that of the control fetuses. The observable differences in comparison to the concurrent control are without any biological relevance.

Weight of placentae:
The mean placental weights in the substance-treated groups (60, 250 and 750 mg/kg body weight/day) were similar to the corresponding control values and did not show any dose dependency.

Weight of fetuses:
The mean fetal body weights in test groups 1, 2 and 3 (60, 250 and 750 mg/kg body weight/day) were not influenced by the test substance administration and were very similar to the corresponding control values.

Soft tissue examination of the fetuses:
Soft tissue malformations were recorded for one low dose and one high dose fetus (60 and 750 mg/kg body weight/day) each.
Unilateral hydronephrosis in combination with hydroureter occurred in female fetus No. 8 from low dose dam No. 44 and a situs inversus was seen in male fetus No. 6 from high dose dam No. 76. The isolated occurrence of these soft malformations does not suggest any relation to dosing.
In total, none out of the 92 examined control fetuses (from 25 litters), one out of 104 low dose fetuses [= 1.0%] (in one out of 25 litters [= 4.0%]), none out of the examined 87 mid dose fetuses (from 22 litters) and one out of 88 high dose fetuses (in one out of 24 litters [= 4.2%]) showed soft tissue malformations. The mean percentages of affected fetuses/litter with soft tissue malformations amounted to 0.0, 0.8, 0.0 and 1.4%, respectively without attaining statistical significance in any of the test groups (60, 250 or 750 mg/kg body weight/day).
Two soft tissue variations (uni- or bilateral dilation of the renal pelvis and/or ureter) were detected in each group including the controls in 8 - 12 fetuses from 4 - 9 litters without any dose-response relationship.
The mean percentages of affected fetuses/litter with total soft tissue variations amounted to 11.8% (control), 13.1% (60 mg/kg body weight/day), 8.5% (250 mg/kg body weight/day) and 9.7% (750 mg/kg body weight/day), respectively. Thus, a relation to dosing is not present and a substance-induced effect concerning the occurrence of soft tissue variations can be excluded with certainty.

No so-called unclassified soft tissue observation (like blood imbibition of kidney(s)) was recorded in any of the fetuses.

Skeletal examination of the fetuses:
The only skeletal malformations, which occurred, were observed for low dose fetus No. 10 from dam No. 34. This fetus was already dead and showed two external malformations, i.e. gastroschisis and scoliosis, when it was developed from the uterus of its mother. The observed additional skeletal malformations (i.e. misshapen thoracic arch (with changed cartilage) and fused rib (with present cartilage)) fit well to the above mentioned external findings.
In total, none of the 105 control fetuses (from 25 litters), one of 115 low dose fetuses [= 0.9%] in one of 25 litters [= 4.0%], none of the 99 mid dose fetuses (from 22 litters) and none of the 103 high dose fetuses (from 24 litters) showed skeletal malformations. The mean percentages of affected fetuses/litter with skeletal malformations amounted to 0.0, 0.7, 0.0, and 0.0%.
The occurrence of two skeletal malformations in one low dose fetus in the absence of any further skeletal malformations in the other examined fetuses from test groups 0 - 3 (0, 60, 250 and 750 mg/kg body weight/day) does not suggest a substance - induced background but is considered to be spontaneous in nature.
In all groups signs of skeletal variations with or without involvement of corresponding cartilaginous structures elicited. The observed variations were related to the skull (supraoccipital and/or basioccipital holes; incomplete ossification of the entire skull, basisphenoid, frontal, parietal, interparietal, supraoccipital and/or hyoid), the vertebral column (incomplete, dumbbell or bipartite ossification of cervical, thoracic, lumbar and/or sacral vertebrae ; supernumerary thoracic vertebra; fused sacral centrum and arch, misshapen sacral vertebra), the ribs (supernumerary 14 th, cervical or wavy ribs), the sternum (misshapen sternebra; unilateral, incomplete, bipartite or missing ossification of sternebra) and the pelvic girdle (incomplete ossification of pubis). The mean percentages of affected fetuses/litter with skeletal variations amounted to 95.1, 93.9, 93.0, and 96.3% at 0, 60, 250 or 750 mg/kg body weight/day. Most of the noted skeletal variations appeared without a clear relation to dosing, without biologically relevant differences between the groups and/or can be found at a comparable frequency in the historical control data. This assessment includes the only skeletal variation, misshapen sacral vertebra, which occurred at a statistically significantly higher rate at 60 and 750 mg/kg body weight/day in comparison to the concurrent control group; 0.0%, 3.1 %* (* = pAdditionally, some isolated cartilage findings without any impact on the respective bony structures, which were designated as unclassified cartilage observations, occurred in all groups including the controls. The observed unclassified cartilage findings were related to the skull, the vertebral column, the ribs and the sternum. The mean percentages of affected fetuses/litter with these findings amounted to 26.9, 32.3, 34.0, and 20.7% at 0, 60, 250 or 750 mg/kg body weight/day. A toxicological relevance for these findings, which did not show any relation to dosing, can be excluded with certainty.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

750 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: embryotoxicity

2

Dose descriptor:

NOAEL

Effect level:

750 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

3

Dose descriptor:

NOAEL

Effect level:

750 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

no effects observed

Overall developmental toxicity

Developmental effects observed:

no

Applicant's summary and conclusion

Executive summary:

DISCUSSION AND CONCLUSION

----------------------------------------

Tridecanol H was administered to pregnant Wistar rats daily by stomach tube from implantation to one day prior to the expected day of parturition (days 6 - 19 post coitum).

Substance-related signs of maternal toxicity occurred at 750 mg/kg body weight/day . The most obvious clinical effects on the high dose dams were transient salivation in all dams immediately after treatment on certain days, urine smeared fur in 4 dams and statistically significantly reduced food consumption at initiation of treatment period (days 6 - 10 p.c .) .

Regarding clinical pathology, statistically significantly increased alanine aminotransferase activities, decreased total protein and globulin concentrations, and increased triglyceride levels in the serum of the high dose females were recorded . These changes, which were accompanied by statistically significantly increased absolute and relative liver weights (about 14% or 18% respectively above control values), are indicative for a mild adverse effect on the liver.

The only substance-induced finding on the mid dose dams (250 mg/kg body weight/day) consisted in transitory salivation in 17 out of 25 rats, which, by itself and if seen in isolation, is not assessed as an adverse or toxic effect.

No substance-induced effects on the dams occurred at the low dose level (60 mg/kg body weight/day).

The oral administration of Tridecanol H to the dams at all 3 dose levels (60 ; 250 and 750 mg/kg body weight/day) had no influence on the gestational parameters. Conception rate, mean number of corpora lutea, total implantations, resorptions and live fetuses, fetal sex ratio or in the values calculated for the pre- and the postimplantation losses were unaffected by treatment.

No substance- related differences were recorded for placental and fetal body weights .

The external, soft tissue and/or skeletal (including cartilage) examinations of the fetuses revealed no differences between the control and the substance-treated groups, which might be related to the test substance administration . Number and type of fetal external, soft tissue and skeletal findings, which were classified as malformations and/or variations, recorded for the 60 ; 250 and 750 mg/kg fetuses were unaffected by treatment. These findings appeared without a clear relation to dosing and/or were seen at incidences previously found to occur spontaneously in control fetuses of this strain of rats . Additionally, there was not found any specific malformation pattern which could be indicative of a selective teratogenicity . Thus the test substance evoked no signs of prenatal developmental toxicity and in particular no indications for teratogenicity at dose levels up to and including 750 mg/kg body weight/day.

Based on these results, the no observed adverse effect level (NOAEL) for maternal toxicity is 250 mg/kg body weight/day, while it is 750 mg/kg body weight/day for prenatal developmental toxicity.