Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 218-880-1 | CAS number: 2273-43-0
Endpoint summary
Administrative data
Key value for chemical safety assessment
Effects on fertility
Description of key information
Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).
OECD 421, Appel (2004)
The NOAEL for maternal toxicity and fertility and developmental effects was determined to be 7500 mg/kg diet (equivalent to 521 mg/ kg body weight/day in males and 433-685 mg/kg body weight/day for females)
Link to relevant study records
- Endpoint:
- screening for reproductive / developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 15 April 2003 to 07 June 2003
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Reason / purpose for cross-reference:
- other: read-across target
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
- Deviations:
- yes
- Remarks:
- but none that affected the study validity
- GLP compliance:
- yes
- Limit test:
- no
- Species:
- rat
- Strain:
- Wistar
- Sex:
- female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Species: Albino rats
- Strain: Wistar outbred (Crl:(WI)WU BR)
- Age at study initiation: 13-14 weeks old females in the satellite repro study (approximately 7 weeks old males from the main 13-week study)
- Weight at study initiation: body weights for females in the satellite groups at the start of treatment ranged from 194.2 - 229.6 g (mean 208.5 g) (For the main study, 135.0 - 167.1 g w/mean 150.7 g for males )
- Feed and drinking water were provided ad libitum.
- Number of animals:
Dose-range finding study: 21 males and 21 females
Main study (13-week subchronic study) - 43 males and 43 females (4 dose groups of 10 rats/sex/dose group)
Satellite study (reproduction/developmental toxicity screening): 44 females
- Acclimation: Upon arrival animals were put in a quarantine room and were given time to acclimate to the new surroundings. The quarantine and acclimatisation periods between arrival and experimental start date were 9, 13, and 13 days for the dose-range finding study, 13-week study, and satellite study, respectively.
- Housing: The animals were housed in one room, in macrolon cages, with sterilised wood shavings as bedding material. 2 (dose-range finding study) or 5 rats (13-week study) were housed per cage, separated by sex. During the premating period, females of the satellite groups were housed 3 or 4 per dose group per cage. During gestation and lactation, the females were housed individually.
ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 3 °C
- Humidity: 30 - 70 %
- Air changes: 10 air changes per hour
- Photoperiod: 12 hr light cycle - Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Details on exposure:
- ADMINISTRATION / EXPOSURE:
- Duration of exposure: females in the satellite reproductive-developmental screening study were exposed for about 5 weeks. (For the repeated dose toxicity evaluation: 14 days or 13 consecutive weeks, dose-range finding study and subchronic study)
- Type of exposure: via the diet
- Doses: 0, 300, 1500 and 7500 mg/kg diet - Details on mating procedure:
- - During the mating period (weeks 10 and 11), one male from the 13-week main study and one female of the satellite group of the same dose group were caged until copulation occurred or two weeks had elapsed.
- Every morning vaginal smears were made to ascertain copulation by detection of sperms.
- The day a smear was sperm-positive was considered gestation day 0. - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- - The analytical method was validated in the matrix under examination (diet) before the start of the study. The test material and other organotin chlorides used as internal standards were converted into the corresponding ethylated tetraorganotin derivatives, which were extracted into the hexane layer. GC-MS analysis was then performed.
- GC-MS was used to determine the achieved concentration, homogeneous distribution and stability of the test material in diet samples. The method of analysis involved derivatisation. This method only measures the amount of the alkyltin moiety, MBT, present and does not identify the other ligands attached to the tin. All measured MBT was attributed to the parent substance, the test material.
- The homogeneity, stability, and achieved concentration (content) of the test material in the diet was analysed in the batch of diets prepared for the dose-range finding study and the 13-week study.
- From these analyses, it was concluded that the test material was homogenously distributed in all diets, the test material was stable in the diets at room temperature for 7 days and in the freezer at <-18 °C for 6 weeks, and the content of the test material was close to the nominal level for all diets. - Duration of treatment / exposure:
- Dose-range finding study: 14 days
Males derived from the main subchronic 13-week study were treated for 3-4 weeks before mating with females from the satellite study around weeks 10-11 age.
Females in the satellite study were treated via the diet starting 2 weeks before mating, during gestation, and up to euthanasia at or shortly after postnatal day 4 (ca. 5 weeks). - Frequency of treatment:
- continuous (in diet)
- Details on study schedule:
- Duration of test: About 6-8 weeks including treatment of males in the main study and females in the satellite study, mating, gestation up to euthanasia at around PND 4.
- Dose / conc.:
- 300 mg/kg diet
- Dose / conc.:
- 1 500 mg/kg diet
- Dose / conc.:
- 7 500 mg/kg diet
- No. of animals per sex per dose:
- Dose-range finding study: 4 rats/sex/dose group; 5 dose groups including controls
13-week main study and satellite study: 10 rats/sex/dose group and 10 females/dose group, respectively; 4 dose groups including controls - Control animals:
- yes, concurrent no treatment
- Details on study design:
- During the premating period females were housed 3 or 4 per group per cage. Male rats of the 13 week study were mated after a premating period of 10 weeks with the female rats.
During the gestation and lactation periods the females were housed individually. If a male died before or during the mating period before the female was found sperm positive, the female was mated with another, proven male of the same group (i.e. a male which already had a successful copulation, sperm positive smear with another female). - Parental animals: Observations and examinations:
- CLINICAL OBSERVATIONS AND FREQUENCY
- Clinical signs: at least once daily (in the morning) and on working days also once in the afternoon.
- Mortality: at least once daily (in the morning) and on working days also at least once in the afternoon.
- Body weight: once during the acclimatisation period, once at initiation of the study prior to introduction of feed and once weekly thereafter. The females of the satellite groups were weighed 4 days before gestation, on gestation days 0, 7, 14 and 21 and on postnatal days 1 and 4. Furthermore, all surviving animals were weighed on the day of necropsy in order to determine their correct organ to body weight ratios.
- Food consumption: measured per cage over weekly periods during premating and gestation period and from PN 1-4 by weighing the feeders (in g/animal/day and g/kg bw).
- Water consumption: provided ad libitum, the amount consumed was not measured.
- Intake of test material: the intake of test material per kg/bw/day was calculated from the nominal dietary concentration of the test material, the food consumption and the mean body weight in the period for which the intake of the test material was calculated.
- Mating: during the mating period every consecutive morning vaginal smears were made to ascertain copulation by detection of sperm cells in the smear. - Oestrous cyclicity (parental animals):
- no
- Sperm parameters (parental animals):
- no
- Litter observations:
- - Parturition and litter evaluation: at the end of the gestation period, females were examined twice daily for signs of parturition. Any difficulties occurring during parturition were recorded. To keep nest disturbance to a minimum, the litters were examined only once daily for dead pups.
- Litter size, sexes and weights: the total litter size and numbers of each sex as well as the number of stillbirths, live and dead pups and grossly malformed pups were evaluated on days 1 and 4 of lactation. The pups were weighed individually and litter weight was calculated for days 1 and 4 of lactation. Mean pup weights were calculated as litter weight/number pups. The number of runts (pup weight < 2 sd from the control litter mean) were noted and reported as well. - Postmortem examinations (parental animals):
- - Macroscopic: all adult animals were subjected to a complete gross necropsy. Organs weighed included: ovaries, uterus (after counting of the implantation sites), thymus and all gross lesions. Samples of latter organs were preserved for microscopic examination.
- Microscopic: microscopic examination of the ovaries, uterus and thymus of the control and 7500 mg/kg groups was performed. Examination was extended to the thymus of the females of the 300 and 1500 mg/kg groups because of the effects observed in the 7500 mg/kg group for this tissue/organ. Furthermore, the reproductive organs of the males of the 300 and 1500 mg/kg groups that failed to sire (did not mate or female was not pregnant) and the reproductive organs of females of the 300 and 1500 mg/kg groups that were non-mated or non-pregnant were microscopically examined. - Postmortem examinations (offspring):
- Necropsy was performed on stillborn pups and pups dying during the study; macroscopic abnormalities were recorded. Pups were examined externally for gross abnormalities and killed by hypothermia at < -18 °C.
- Statistics:
- - Test material analysis:
Homogeneity: one way analysis of variance (Anova) using the sample location (1-5) as grouping factor. The test material was considered to be homogeneously distributed in the diets if p > 0.01 and/or if the relative standard deviation (RSD) between the samples means was less than or equal to 15 %.
Stability: one way analysis of variance (Anova) using time as grouping factor. The test material was considered to be stable in the diets if p > 0.01 and/or if the mean concentration on the last day was between 80 and 120 % of the mean concentration on the first day (t =0).
Achieved concentration: for each concentration level, the mean of the concentrations, as measured in the diet samples used for the assessment of the homogeneity, was considered to represent the achieved concentration. The content of the test material in the diet was considered to be 'close to intended' if the mean measured concentration was between 80 and 120 % of the intended concentration.
- Body weight: one way analysis of covariance (covariate: body weight on day 0) followed by Dunnett's multiple comparison tests.
- Food consumption and food efficiency: one way analysis of variance (Anova) followed by L.S.D. tests.
- Fisher's exact probability test was used to evaluate the number of mated and pregnant females and females with live pups. Number of implantation sites, live and dead pups were evaluated by Kruskal-Wallis nonparametric analysis of variance followed by the Mann-Whitney U-test.
- Histopathological changes: Fisher's exact probability test.
The litter was used as the statistical unit for calculations of foetal values.
All tests were two-sided. Probability values of p < 0.05 were considered significant. - Reproductive indices:
- With regard to fertility and reproductive performance, the following parameters were calculated:
- pre-coital time = time between the start of mating and successful copulation
- duration of gestation = time between gestation day 0 and day of delivery
- mating index = (number of females mated/number of females placed with males) x 100
- male fertility index = (number of males that became sires/number of males placed with females) x 100
- female fertility index = (number of pregnant females/number of females placed with males) x 100
- female fecundity index = (number of pregnant females/number of females mated) x 100
- gestation index = (number of females with live pups/number of females pregnant) x 100
- live birth index = (number of pups born alive/number of pups born) x 100 - Offspring viability indices:
- - pup mortality day n = (number of dead pups on day n/total number of pups on day n) x 100
- viability index day 1-4 = (number of pups surviving 4 days/total number of live pups on day 1) x 100
- sex ratio day n = (number of live male pups on day n/ number of live pups on day n) x 100
- post-implantation loss = [(number of implantation sites - number of pups born alive)/number of implantation sites] x 100 - Clinical signs:
- no effects observed
- Description (incidence and severity):
- No treatment related clinical signs were observed during the premating, mating, gestation and lactation periods.
- Dermal irritation (if dermal study):
- not examined
- Mortality:
- no mortality observed
- Description (incidence):
- No mortality occurred.
- Body weight and weight changes:
- no effects observed
- Description (incidence and severity):
- - Mean body weight of the females of the 7500 mg/kg group was statistically significantly increased on GD 21 and body weight change was also statistically significantly increased from GD 14-21. During the premating, gestation and lactation periods, no other significant differences in mean body weights and body weight changes of the females were observed.
- Mean food consumption of the females (in g/animal/day and g/kg bw/day) of the 7500 mg/kg group was statistically significantly increased from GD 14-21. During the premating, gestation and lactation periods, no other significant differences in mean food consumption of the females were observed. - Food consumption and compound intake (if feeding study):
- no effects observed
- Description (incidence and severity):
- The test material intake of the female animals of the 300, 1500 and 7500 mg/kg groups was respectively:
Premating period
days 0-7: 19.1, 92.2 and 433.4 mg/kg bw/day
days 7-14: 18.7, 91.4 and 476.4 mg/kg bw/day
Gestation period
GD 0-7: 21.7, 101.8 and 526.2 mg/kg bw/day
GD 7-14: 21.0, 96.5 and 544.0 mg/kg bw/day
GD 14-21: 15.2, 77.3 and 494.3 mg/kg bw/day
Lactation period PN 1-4: 25.3, 140.8 and 684.7 mg/kg bw/day - Food efficiency:
- not specified
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not specified
- Haematological findings:
- not specified
- Clinical biochemistry findings:
- not specified
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not examined
- Organ weight findings including organ / body weight ratios:
- no effects observed
- Histopathological findings: non-neoplastic:
- no effects observed
- Description (incidence and severity):
- - Reproductive organs and the thymuses of the control and 7500 mg/kg dose groups were examined microscopically. In addition, reproductive organs of the 300 and 1500 mg/kg groups of non-pregnant females and males that failed to sire were examined.
- All histopathological changes in the testes, epididymides, prostate and in the ovaries, uterus and thymuses represent common findings in rats of this strain and age. Moreover, they occurred only incidentally or at similar incidences amongst the groups, including controls. Therefore, they were not considered to be related to treatment. - Histopathological findings: neoplastic:
- not specified
- Other effects:
- no effects observed
- Description (incidence and severity):
- Analysis of the test material in diet samples revealed that the test material dose was close to the nominal level for all diets.
Homogeneity: The test material was considered to be homogeneously distributed in all diets.
Stability: The test material was considered to be stable in the diets upon storage at room temperature for 7 days and in the freezer at < -18 °C for 6 weeks. - Reproductive function: oestrous cycle:
- not examined
- Reproductive function: sperm measures:
- not examined
- Reproductive performance:
- no effects observed
- Description (incidence and severity):
- - Pre-coital time: comparable among the control and treated groups.
- Mating index: 90 - 100 %
- Number pregnant per dose level: 6, 6, 7 and 7 for the control, 300, 1500 and 7500 mg/kg groups, respectively.
- Female fecundity index: comparable among the control and treated groups.
- Female fertility index: comparable among the control and treated groups.
- Male fertility index: comparable among the control and treated groups.
- Number of implantations: 11-13 (control group), 10-14 (300 mg/kg), 11-14 (1500 mg/kg), 11-13 (7500 mg/kg).
- Gestation index: 100 % in the control, 300, 1500 and 7500 mg/kg groups. - Key result
- Dose descriptor:
- NOAEL
- Remarks:
- maternal toxicity
- Effect level:
- 7 500 mg/kg diet
- Based on:
- test mat.
- Sex:
- female
- Basis for effect level:
- other: No significant health effects were observed at the highest dose tested. This dietary dose level is equivalent to 433-685 mg/kg bw/day for females.
- Clinical signs:
- not examined
- Dermal irritation (if dermal study):
- not examined
- Mortality / viability:
- no mortality observed
- Body weight and weight changes:
- effects observed, non-treatment-related
- Description (incidence and severity):
- Mean pup weight on PN 1 and 4 of the 7500 mg/kg group was statistically significantly increased. Pup weight change of the pups from the 7500 mg/kg group between PN 1-4 was not statistically significantly increased. No effect on pup weight and pup weight change was observed in the other treated groups when compared to the control group.
- Food consumption and compound intake (if feeding study):
- not examined
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- not examined
- Clinical biochemistry findings:
- not examined
- Urinalysis findings:
- not examined
- Sexual maturation:
- not examined
- Organ weight findings including organ / body weight ratios:
- not examined
- Gross pathological findings:
- no effects observed
- Description (incidence and severity):
- The incidence of runts in the 1500 mg/kg group was statistically significantly increased on PN 1; this observation was only significant on pup basis. No statistically significant difference was observed between the other treated groups and the control group. Macroscopic observation of the stillborn pups revealed no abnormalities of the pups of the 300 and 1500 mg/kg dose groups. The stillborn pup of the 7500 mg/kg group was partly cannibalised; as far as possible no abnormalities were observed in this pup.
- Histopathological findings:
- not examined
- Other effects:
- no effects observed
- Description (incidence and severity):
- - Litter size: The mean number of pups delivered per litter amounted to 8.7, 10.8, 11.0 and 11.3 for the control, 300, 1500 and 7500 mg/kg groups, respectively.
- Live birth index: 100, 100, 100 and 96 % in the control, 300, 1500 and 7500 mg/kg groups, respectively.
- Number of females with live born pups: 6, 6, 7 and 7 in the control, 300, 1500 and 7500 mg/kg groups, respectively.
- Number of females with stillborn pups: 0, 0, 0 and 3 for the control, 300, 1500 and 7500 mg/kg groups, respectively.
- Number of females with all stillborn pups: 0 for the control and all treated groups.
- Post implantation loss: 29.1, 11.4, 17.2 and 10.7 % for the control, 300, 1500 and 7500 mg/kg
- Pup mortality: 0, 0, 0 and 3.8 % for the control, 300, 1500 and 7500 mg/kg groups, respectively (PN 1)
- Number viable: The viability index (PN 1-4) was 100 % in the control, 300, 1500 and 7500 mg/kg groups.
- Number of live pups per litter: 8.7, 10.8, 11.0 and 10.9 for the control, 300, 1500 and 7500 mg/kg groups, respectively (PN 1); 8.7, 10.8, 10.1 and 10.9 for the control, 300, 1500 and 7500 mg/kg groups, respectively (PN 4).
- Sex ratio: No difference was observed in the sex ratio between the groups. - Behaviour (functional findings):
- not examined
- Developmental immunotoxicity:
- not examined
- Key result
- Dose descriptor:
- NOAEL
- Remarks:
- reproductive and developmental toxicity
- Generation:
- F1
- Effect level:
- 7 500 mg/kg diet
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: No significant health effects were observed at the highest dose tested. This dietary dose level is equivalent to 521 mg/kg bw/day in males and 433-685 mg/kg bw/day for females.
- Reproductive effects observed:
- no
- Conclusions:
- As no maternal toxicity or reproductive effects in the females of the satellite groups after mating with the male animals of the main study were observed at the high-dose level of this study, this dose level 7500 mg/kg diet (equivalent to 521 mg/ kg body weight/day in males and 433-685 mg/kg body weight/day for females) can be considered as a NOAEL for maternal toxicity and fertility and developmental effects.
- Executive summary:
The toxicity of the test material in Wistar rats was examined using continuous administration via the diet for 13 consecutive weeks in accordance with OECD 408. In satellite groups of female rats a reproduction/developmental screening test was performed in accordance with OECD 421 to provide initial data on the possible reproductive and developmental effects of the test material. The study was performed under GLP conditions.
The main study used four groups of 10 rats/sex (13-week study) and the satellite study used four groups of 10 female rats (reproduction/developmental screening study). For both studies the control group was kept on untreated diet and three test groups received experimental diets containing 300, 1 500 and 7 500 mg/kg (ppm) of the test material. The dose levels used in both studies were selected based on the results of a preceding dose range finding study.
In the satellite study female rats were fed their respective diets beginning two weeks prior to the mating period, and continued through mating, gestation and up to PN 4 or shortly thereafter. Male rats from the main study were mated after a premating period of 10 weeks with female rats of the satellite groups which were fed the same dose of test diet.
Clinical observations, growth, food consumption, food conversion efficiency, neurobehavioural testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy, microscopic examination of various organs and tissues and assessment of various reproductive and developmental parameters were used as
criteria for detecting the effects of treatment.
The calculated doses for the females receiving 300, 1500, or 7500 mg/kg test material in the diet ranged from 15.2- 25.3, 77.3-140.8, and 433.4- 684.7 mg/kg body weight/day. None of the few changes observed in clinical signs, body weight, food consumption, fertility and reproductive performance, litter data, organ weights, gross macroscopy and microscopic examination were considered treatment-related.
As no maternal toxicity or reproductive effects in the females of the satellite groups after mating with the male animals of the main study were observed at the high-dose level of this study, this dose level 7500 mg/kg diet (equivalent to 521 mg/ kg body weight/day in males and 433-685 mg/kg body weight/day for females) can be considered as a NOAEL for maternal toxicity and fertility and developmental effects.
- Endpoint:
- screening for reproductive / developmental toxicity
- Type of 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:
- other: Study conducted on read-across material
- Justification for type of information:
- Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3), see attached justification.
- Reason / purpose for cross-reference:
- read-across source
- Key result
- Dose descriptor:
- NOAEL
- Remarks:
- maternal toxicity
- Effect level:
- 7 500 mg/kg diet
- Based on:
- test mat.
- Sex:
- female
- Basis for effect level:
- other: No significant health effects were observed at the highest dose tested. This dietary dose level is equivalent to 433-685 mg/kg bw/day for females.
- Key result
- Dose descriptor:
- NOAEL
- Remarks:
- reproductive and developmental toxicity
- Generation:
- F1
- Effect level:
- 7 500 mg/kg diet
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- other: No significant health effects were observed at the highest dose tested. This dietary dose level is equivalent to 521 mg/kg bw/day in males and 433-685 mg/kg bw/day for females.
- Reproductive effects observed:
- no
Referenceopen allclose all
Effect on fertility: via oral route
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- NOAEL
- 433 mg/kg bw/day
- Study duration:
- subacute
- Species:
- rat
Effect on fertility: via inhalation route
- Endpoint conclusion:
- no study available
Effect on fertility: via dermal route
- Endpoint conclusion:
- no study available
Additional information
Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).
Appel (2004)
The toxicity of the test material in Wistar rats was examined using continuous administration via the diet for 13 consecutive weeks in accordance with OECD 408. In satellite groups of female rats a reproduction/developmental screening test was performed in accordance with OECD 421 to provide initial data on the possible reproductive and developmental effects of the test material. The study was performed under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).
The main study used four groups of 10 rats/sex (13-week study) and the satellite study used four groups of 10 female rats (reproduction/developmental screening study). For both studies the control group was kept on untreated diet and three test groups received experimental diets containing 300, 1 500 and 7 500 mg/kg (ppm) of the test material. The dose levels used in both studies were selected based on the results of a preceding dose range finding study.
In the satellite study female rats were fed their respective diets beginning two weeks prior to the mating period, and continued through mating, gestation and up to PN 4 or shortly thereafter. Male rats from the main study were mated after a premating period of 10 weeks with female rats of the satellite groups which were fed the same dose of test diet.
Clinical observations, growth, food consumption, food conversion efficiency, neurobehavioural testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy, microscopic examination of various organs and tissues and assessment of various reproductive and developmental parameters were used as criteria for detecting the effects of treatment.
The calculated doses for the females receiving 300, 1500, or 7500 mg/kg test material in the diet ranged from 15.2- 25.3, 77.3-140.8, and 433.4- 684.7 mg/kg body weight/day. None of the few changes observed in clinical signs, body weight, food consumption, fertility and reproductive performance, litter data, organ weights, gross macroscopy and microscopic examination were considered treatment-related.
As no maternal toxicity or reproductive effects in the females of the satellite groups after mating with the male animals of the main study were observed at the high-dose level of this study, this dose level 7500 mg/kg diet (equivalent to 521 mg/ kg body weight/day in males and 433-685 mg/kg body weight/day for females) can be considered as a NOAEL for maternal toxicity and fertility and developmental effects.
Effects on developmental toxicity
Description of key information
Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).
Two key studies were presented to address this endpoint. Both studies were performed under GLP conditions and in accordance with standardised guidelines US EPA OPPTS 870.3700 and OECD 414. In both studies, the test material was found not to be teratogenic to rats and rabbits. Adverse pregnancy outcomes were observed in rabbits only; however these were concluded to be test material related, but secondary to maternal toxicity.
Link to relevant study records
- Endpoint:
- developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 21 January 2014 to 31 March 2014
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Reason / purpose for cross-reference:
- other: read-across target
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 414 (Prenatal Developmental Toxicity Study)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
- Deviations:
- no
- GLP compliance:
- yes
- Limit test:
- no
- Species:
- rat
- Strain:
- other: Crl:CD (SD)
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Age at study initiation: 8 to 10 weeks
- Weight at study initiation: 177 to 247 g
- Housing: individually housed in solid bottom cages with nonaromatic woodchip bedding
- Diet: ad libitum
- Water: tap water available ad libitum from an automatic watering system
ENVIRONMENTAL CONDITIONS
- Temperature: 68 to 79 °F
- Humidity: 30 to 70 %
- Photoperiod: 12 hour light/dark cycle
IN-LIFE DATES: From: 21 and 22 January 2014 To: 11 February 2014 - Route of administration:
- oral: gavage
- Vehicle:
- corn oil
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS: Formulations of the test material in the vehicle were prepared weekly and stored refrigerated at 2 to 8 °C. Formulations were prepared at nominal concentrations of 20, 60 and 200 mg/mL.
VEHICLE
- Justification for use and choice of vehicle (if other than water): The vehicle was selected based on information from a pilot study.
- Concentration in vehicle: 20, 60 and 200 mg/mL.
- Amount of vehicle (if gavage): 5 mL/kg - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- Dosing samples were evaluated for homogeneity and concentration. 1 mL samples were collected for homogeneity during week 1 from the top, middle and bottom of the 100 and 1000 mg/kg formulations. Samples from all concentrations were taken during weeks 1 and 2 from the middle stratum for analysis of concentration. The dose formulations were analysed using HPLC/UV.
HPLC/UV CONDITIONS
Column: Agilent Poroshell 120 SB-C8 column, 3.0 x 50 mm
Gradient flow: 0.05 % trifluoroacetic acid in water (mobile phase A) and acetonitrile (mobile phase B) at a flow rate of 1.0 mL/minute.
Wavelength: 230 nm
Derivatisation: Prior to analysis, duplicate samples were derivatised in hexane and phenylmagnesium bromide then diluted with isopropyl alcohol to within the range of the calibration curve. Vehicle samples were also derivitised and then diluted using a dilution factor of 100.
RESULTS
- Homogeneity
Analysis of the low- and high-dose formulations (20 and 200 mg/mL, respectively) used for dosing the first week of study confirmed they were homogeneous as prepared as each formulation met the laboratory’s acceptance criteria of 100 ± 15 % of nominal and % RSD (Relative Standard Deviation) ≤ 10.
- Concentration
The test formulations used for dosing the first two weeks of study analysed between 97.8 and 101.4 % of nominal with the % RSDs ranging between 0.127 to 3.344, confirming that animals were receiving the appropriate dose levels when treated at 5 mL/kg/dose. The laboratory’s acceptance criteria for concentration were similar to that for homogeneity (100 ± 15 % of nominal and %RSD ≤ 10). No test material was found in the control vehicle samples. - Details on mating procedure:
- - Impregnation procedure: purchased timed pregnant
- Duration of treatment / exposure:
- Gestation day 0 to 19
- Frequency of treatment:
- Once daily
- Duration of test:
- 19 days
- Dose / conc.:
- 100 mg/kg bw/day (nominal)
- Dose / conc.:
- 300 mg/kg bw/day (nominal)
- Dose / conc.:
- 1 000 mg/kg bw/day (nominal)
- No. of animals per sex per dose:
- 25 females per dose
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- - Dose selection rationale: Doses were selected based on information from a pilot study. In the pilot study, dose levels of 75, 150, 300, and 600 mg/kg/day were evaluated. Animals were treated orally from GD 0 to 19. No maternal or developmental toxicity was observed at these dose levels in the pilot study. Therefore, in the absence of maternal toxicity at the 600 mg/kg/day dose level in the pilot study, the high dose level in the definitive study was increased to 1000 mg/kg/day, a limit dose.
- Maternal examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily
- Cage side observations: Morbidity, mortality, injury and availability of food and water.
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily
- Examinations: Animals were removed from the cage and given a detailed clinical examination. The observations included, but were not limited to, evaluation of the skin, fur, eyes, ears, nose, oral cavity, thorax, abdomen, external genitalia, limbs and feet, respiratory and circulatory effects, autonomic effects such as salivation, nervous system effects including tremors, convulsions, reactivity to handling and unusual behaviour.
BODY WEIGHT: Yes
- Time schedule for examinations: Gestation days 0, 3, 6, 9, 12, 15, 18 and 20. Body weight change was calculated for gestation days 0-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-20 and 0-20. Adjusted body weight (minus gravid uterus) and adjusted bodyweight change were also calculated.
FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Time schedule for examinations: Food consumption was measured and recorded on the corresponding body weight days and calculated for the same intervals.
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20. Each surviving female was euthanised by carbon dioxide inhalation, followed by exsanguination of the abdominal vena cava and immediately subjected to a caesarean section.
- Organs examined: Dams were subjected to a complete necropsy. Special emphasis was placed on structural abnormalities or pathologic changes that may have influenced pregnancy. - 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 - Fetal examinations:
- - External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: all per litter - Statistics:
- All parental in-life data, gravid uterine weights, corpora lutea/dam, total implantations/dam, litter size/dam, viable foetuses/dam, total number of resorptions/dam, number of early resorptions/dam and number of late resorptions/dam were assessed using group pair-wise comparisons. Levene's test was used to assess homogeneity of group variances for each specified endpoint and for all collection intervals. If Levene's test was not significant (p≥0.01), a pooled estimate of variance (Mean Square Error) was computed from a one-way analysis of variance (ANOVA) and utilised by a Dunnett's comparison of each treatment group with the control. If the Levene's test was significant (p<0.01), then Welch's t-test was used with a Bonferroni correction for comparisons with the control group. All endpoints were analysed using two-tailed tests.
Foetal sex ratio (% males/litter), % preimplantation loss and % postimplantation loss were analysed using Arcsin-Square-Root Transformation. Data presented as percentages were transformed using the arcsin of the square root and analysed in accordance with the group pair-wise comparisons.
Pregnancy index, malformations and variations were all evaluated using Fisher’s exact test. An overall test for association between response and treatment was performed. If this test was significant (p<0.05) and there were more than two groups, then each treatment group was compared to the control group. All endpoints were analysed sing two-tailed tests. Overall testing and follow-up pair-wise testing was conducted for the control and all treatment groups that had sufficient sample size (n≥3).
Mean foetal bodyweights were analysed by covariate analysis by comparing treatment groups for each endpoint (mean of foetal bodyweights per female). The covariate was litter size. Each treatment satisfying the sample size assumption was compared to the control using Dunnett's test under the analysis of covariance model. Endpoints were analysed using two tailed tests. - Indices:
- - Viable foetuses
- Postimplantation loss = ((No. implantations - No. viable foetuses) / No. implantations) x 100
- Preimplantation loss = ((No. corpora lutea - No. implantations) / No. corpora lutea) x 100
- Pregnancy index = (No. pregnant females - No. females with evidence of mating) x 100
- Foetal sex ratio - Historical control data:
- A large database of historical control data for the rat was available for comparison.
- Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- - Salivation was observed at least once in 1, 1 and 16 animals in the 100, 300 and 1000 mg/kg bw/day groups, respectively. Audible breathing, likely related to the salivation, was observed at least once in two, three, and ten animals in the low, mid and high dose groups respectively. Audible breathing was not heard post administration in the control group. This was considered to be a pharmacologic response to the test material.
- Dermal irritation (if dermal study):
- not examined
- Mortality:
- mortality observed, non-treatment-related
- Description (incidence):
- - Administration of the test material had no effect on maternal survival. All animals in the control group and 100 mg/kg bw/day group survived until necropsy.
- One death occurred in each of the 300 and 1000 mg/kg bw/day groups on gestation days 17 and 20, respectively. These were not attributed to test material administration. - Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- - No effect on bodyweight or body weight change was observed in the 100 and 300 mg/kg bw/day groups.
- In the 1000 mg/kg bw/day group, mean body weights on gestation day 18 and 20 were 6 and 7 % lower, respectively, than mean control values. These differences were statistically significant and attributed to test material administration. Mean body weight gain for this group between gestation days 9 to 12 was 14 % higher than the control group and 62, 32 and 18 % lower between gestation days 12 to 15, 15 to 18 and 18 to 20, respectively. Between gestation days 0 to 20 the bodyweight gain for this group overall was 15 % lower than controls. Several animals in the 1000 mg/kg bw/day group were found to have experienced weight loss during the study. With the exception of the animal found dead on GD 20 which was found at necropsy to have a white paste-like foreign material extending the length of the oesophagus and into the stomach (which was determined to be ingested bedding material), the cause of the weight loss for the animals in this group was attributed to lower food consumption. - Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Description (incidence and severity):
- - No effect on maternal food consumption was noted in the 300 and 100 mg/kg bw/day dose groups and values were comparable to mean control values.
- In the high dose group, food consumption was statistically lower than controls over GD 0 to 3 (- 12 %), GD 15 to 18 (-22 %), GD 18 to 20 (-14 %) and GD 0 to 20 (-9 %). This was attributed to test material administration and correlated, particularly in late in gestation, with lower body weights and body weight gains. - Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- not specified
- Clinical biochemistry findings:
- not specified
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- - At necropsy, no effect of treatment with the test material was noted in the 100 mg/kg bw/day dose level. The few findings in this group occurred at a low incidence and were not attributed to test material administration.
- Foreign material generally identified as white in colour, which appeared to be bedding material, was observed in seven and twenty three females in the 300 and 1000 mg/kg bw/day groups, respectively. This was not observed in the control or low dose group animals. The toxicological significance of this finding is unclear. Other macroscopic findings in the 300 mg/kg bw/day group were of low incidence and not considered to be related to test material administration.
- In the 1000 mg/kg bw/day dose group, all 25 animals were found to have white foci in the nonglandular portion of the stomach. The occurrence of this finding was considered to be test material related. - Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- not specified
- Histopathological findings: neoplastic:
- not specified
- Other effects:
- not examined
- Number of abortions:
- not specified
- Pre- and post-implantation loss:
- no effects observed
- Description (incidence and severity):
- There were no treatment related effects on uterine implantation data.
- Total litter losses by resorption:
- not specified
- Early or late resorptions:
- not specified
- Dead fetuses:
- no effects observed
- Description (incidence and severity):
- - 25, 24, 24 and 24 litters, in the control, low, mid and high dose groups respectively, were produced with viable foetuses to examine on GD 20.
- Changes in pregnancy duration:
- not examined
- Changes in number of pregnant:
- no effects observed
- Description (incidence and severity):
- Pregnancy indices were 100, 96, 100 and 100 % in the control, low, mid and high dose groups, respectively.
- Other effects:
- effects observed, non-treatment-related
- Description (incidence and severity):
- - There were no treatment related effects on uterine implantation data. The mean number of corpora lutea in the 300 mg/kg bw/day group was statistically lower than the control group. This was considered to be spurious as ovulation occurred prior to the start of treatment. Additionally the reduction in number of corpora lutea in this group had no impact on uterine implantation data.
- Mean gravid uterine weights, adjusted GD 20 body weights and adjusted GD 0 to 20 body weight change in the 100 and 300 mg/kg bw/day groups were comparable to the mean control values. In the 1000 mg/kg bw/day group, the mean gravid uterine weight was statistically lower than the mean control value. This was attributed to lower foetal body weights. The mean adjusted GD 20 body weight and GD 0 to 20 change were also statistically lower, which correlated with lower bodyweights and bodyweight change at GD 20 in this group. - Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- Abnormalities:
- not specified
- Fetal body weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- - In the 100 and 300 mg/kg bw/day group, no effect on foetal body weight was observed and body weights were comparable to the control group. In the 1000 mg/kg bw/day group, foetal body weights were 8.6 % lower for combined sexes and 8.1 and 8.6 % lower for males and females, respectively. This was found to be statistically significant and considered an effect of test material administration.
- Reduction in number of live offspring:
- not examined
- Changes in sex ratio:
- no effects observed
- Description (incidence and severity):
- Foetal sex ratios were not affected by the administration of the test material. Mean sex ratios ranged from 51.5 to 58.3 % and were comparable to the mean control ratio of 52.0 %.
- Changes in litter size and weights:
- not specified
- Changes in postnatal survival:
- not examined
- External malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- No external malformations or variations were attributed to test material administration at all dose levels tested. Two foetuses in one litter of the 300 mg/kg bw/day group were found to have oedema and a meningoencephalocele defect and entire body discolouration and protruding tongue. These observations were only noted in two foetuses from the same litter. In the absence of any findings in the 1000 mg/kg bw/day group, these were therefore not considered to be test material related.
- Skeletal malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- - No skeletal malformations or variations were attributed to test material administration. In the 100 mg/kg bw/day group, five foetuses from a single litter had bent long bones of the forelimbs (humerus, radius and/or ulna) and bent scapulae. With the exception of bent scapulae, these malformations are known to have low historical incidence in the performing laboratory and in the absence of similar malformations at higher dose groups, this was considered to be incidental. The dam with the affected litter was noted to have intervals of weight loss and low food consumption during the study and was found to have adhesions within the thoracic cavity and clear fluid at necropsy. The observations in the foetuses for this dam were attributed to the poor health of the dam during the study. In the 300 mg/kg bw/day group two foetuses from separate litters were noted to have dissimilar skeletal malformations. In the 1000 mg/kg bw/day group, two foetuses from the same litter had shortened bones of the fore and hind limbs, short or misshapen exoccipital bones of the skull and misshapen scapula. These were not attributed to test material administration. No other skeletal malformations were noted in foetuses from this group.
- Skeletal developmental variations in the treated groups were found to be comparable to the control group. Their occurrence within the treated groups were generally within the historical control data range. - Visceral malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- In the 1000 mg/kg bw/day group, the only visceral malformation observed was a folded retina in a single foetus. This was considered to be spontaneous and unrelated to test material administration.
- Other effects:
- not examined
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- fetal/pup body weight changes
- Abnormalities:
- not specified
- Developmental effects observed:
- not specified
- Conclusions:
- Under the conditions of the test, the NOAEL for developmental toxicity and maternal toxicity were 300 mg/kg bw/day based on lower foetal body weight and lower bodyweight, bodyweight gain and food consumption observed in dams treated with 1000 mg/kg bw/day. There were no teratogenic effects recorded in the study.
- Executive summary:
The developmental toxicity potential of the test material was investigated in the rat in a study performed in accordance with the standardised guidelines OECD 414 and US EPA OPPTS 870.3700 under GLP conditions.
The test material was administered to timed pregnant Crl:CD (SD) rats via oral gavage in corn oil from gestation day 0 to gestation day 19 at doses of 0, 100, 300 or 1000 mg/kg bw/day. Observations of the animals included clinical signs, body weights and food consumption. Animals were sacrificed on gestation day 20. The dams underwent ovarian and uterine examinations and necropsy. The foetuses were examined for external, skeletal and visceral malformations and variations.
No treatment-related effect was observed on survival. The death of one animal in each of the 300 and 1000 mg/kg/day dose groups was not considered test material related. Salivation and audible breathing were observed in the treated groups and considered a pharmacologic response to the test material. No effect of treatment at the 100 and 300 mg/kg/day dose levels was observed on gestation body weights, body weight change, or food consumption. At the 1000 mg/kg/day dose level, maternal toxicity was observed due to statistically significant changes from mean control values of the following: lower body weights on GD 18 (-6 %) and GD 20 (-7 %); lower body weight gain GD 12 to 15 (-62 %), GD 15 to 18 (-32 %), GD 18 to 20 (-18 %), and GD 0 to 20 (-15 %); and lower food consumption GD 0 to 3 (-12 %), GD 15 to 18 (-22 %), GD 18 to 20 (-14 %), and GD 0 to 20 (-9 %). A common finding in all the 1000 mg/kg/day animals only at macroscopic examination was white foci in the nonglandular portion of the stomach. Another finding included foreign material generally identified as white in colour and having the appearance of bedding was observed in 7/25 and 23/25 females in the 300 and 1000 mg/kg/day dose groups, respectively, but not observed among the control or 100 mg/kg/day animals. The reason for these animals ingesting the bedding and its toxicological significance in relation to the test material are unclear.
No effect of the test material at dose levels ≤1000 mg/kg/day was observed on pregnancy indices, uterine implantation data, foetal sex ratios, or foetal external, visceral, or skeletal examinations. Lower foetal body weights (8 % lower than controls) were observed at 1000 mg/kg/day. Thus, the No-Observed-Adverse-Effect Level (NOAEL) for maternal and developmental toxicity was 300 mg/kg/day. There were no teratogenic effects recorded in the study.
- Endpoint:
- developmental toxicity
- Type of 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:
- other: Study conducted on read-across material
- Justification for type of information:
- Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3), see attached justification.
- Reason / purpose for cross-reference:
- read-across source
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- food consumption and compound intake
- Abnormalities:
- not specified
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- fetal/pup body weight changes
- Abnormalities:
- not specified
- Developmental effects observed:
- not specified
- Endpoint:
- developmental toxicity
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 10 June 2014 to 05 September 2014
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Reason / purpose for cross-reference:
- other: read-across target
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 414 (Prenatal Developmental Toxicity Study)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
- Deviations:
- no
- GLP compliance:
- yes
- Limit test:
- no
- Species:
- rabbit
- Strain:
- New Zealand White
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Strain: Hra: (NZW)SPF
- Age at study initiation: 5 to 5.5 months
- Weight at study initiation: 2.56 to 3.63 kg
- Housing: Individually housed in suspended, stainless steel, slatted floor cages. Animal enrichment was provided.
- Diet: Limited to 50 g/animal/day on arrival (GD 0) and increased on second day of acclimation to approximately 170 g/animal/day for the remainder of the study. Enrichment food was offered on occasion.
- Water: tap water was available ad libitum via an automatic watering system
- Acclimation period: 1 day
ENVIRONMENTAL CONDITIONS
- Temperature: 61-72 °F
- Humidity: 30 to 70 %
- Photoperiod: 12 hour light/dark cycle
IN-LIFE DATES: From: 10 June 2014 To: 11 July 2014 - Route of administration:
- oral: gavage
- Vehicle:
- corn oil
- Details on exposure:
- PREPARATION OF DOSING SOLUTIONS: The test material in vehicle was prepared weekly and stored refrigerated at 2 to 8 °C (protected from light).
VEHICLE
- Justification for use and choice of vehicle (if other than water): The vehicle was selected based on information from a pilot study.
- Concentration in vehicle: 60, 120 and 240 mg/mL
- Amount of vehicle (if gavage): 0.5 mg/mL - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- Dosing samples were evaluated for homogeneity and concentration. 1 mL samples were collected for homogeneity during week 1 from the top, middle and bottom of the 30 and 120 mg/kg formulations. Samples from all concentrations were taken during weeks 1 and 4 from the middle stratum for analysis of concentration. The dose formulations were analysed using HPLC/UV.
HPLC/UV CONDITIONS
Column: Agilent Poroshell 120 SB-C8 column, 3.0 x 50 mm
Gradient flow: 0.05 % trifluoroacetic acid in water (mobile phase A) and acetonitrile (mobile phase B) at a flow rate of 1.0 mL/minute.
Wavelength: 230 nm
Derivatisation: Prior to analysis, duplicate samples were derivatised in hexane and phenylmagnesium bromide then diluted with isopropyl alcohol to within the range of the calibration curve. Vehicle samples were also derivitised and then diluted using a dilution factor of 100.
RESULTS
- Homogeneity:
Analysis of the low- and high-dose formulations (60 and 240 mg/mL, respectively) used for dosing the first week of study confirmed they were homogeneous as prepared, meeting the laboratory’s acceptance criteria of 100 ± 15 % of nominal, and percent relative standard deviation (RSD) ≤ 10.
- Concentration:
Mean concentrations of formulations used for dosing in Weeks 1 and 4 of study ranged between 96.7 and 104.7 % of nominal with percent RSDs ranging between 0.523 and 2.649, confirming that animals were receiving the appropriate dose levels when the formulation was administered at 0.5 mL/kg. No test material was detected in the control samples. - Details on mating procedure:
- - Impregnation procedure: purchased timed pregnant
- Duration of treatment / exposure:
- Gestation day 1 to 28
- Frequency of treatment:
- Once daily
- Duration of test:
- 29 days
- Dose / conc.:
- 30 mg/kg bw/day (nominal)
- Dose / conc.:
- 60 mg/kg bw/day (nominal)
- Dose / conc.:
- 120 mg/kg bw/day (nominal)
- No. of animals per sex per dose:
- 25 females per dose
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- - Dose selection rationale: Doses were selected based on information from a pilot study.
In the pilot study, dose levels of 30, 65, 140 and 300 mg/kg/day were evaluated. However, due to reduced food consumption levels in several groups by GD 5, the dose levels were adjusted to 30 (unchanged), 50, 100 and 200 mg/kg/day. On GD 8, the 200/300 mg/kg/day dose group was terminated due to continued low food consumption, weight loss and being in a state of in extremis. In all remaining groups there was variability in food consumption as expected with the corn oil vehicle administered at 1 mL/kg/day. One animal died in the 100 mg/kg/day dose group (cause undetermined from necropsy observations) and one animal aborted in each of the 30 and 100 mg/kg/day dose groups. The aborted pregnancies were preceded by lengthy periods of inappetence. The maternal toxicity observed in the pilot study was considered largely attributed to the 1 mL/kg corn oil vehicle treatment and in the main study this volume was reduced to 0.5 mL/kg. No effect of treatment to 100 mg/kg/day was observed on uterine implantation data or foetal external examinations. There was about a 10% reduction in mean foetal body weight at the 100 mg/kg/day dose level relative to controls. - Maternal examinations:
- CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily
- Cage side observations: Morbidity, mortality, injury and availability of food and water.
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily
- Examinations: Animals were removed from the cage and given a detailed clinical examination. On occasion, clinical observations were recorded at unscheduled intervals. The observations included, but were not limited to, evaluation of the skin, fur, eyes, ears, nose, oral cavity, thorax, abdomen, external genitalia, limbs and feet, as well as evaluation of respiration.
BODY WEIGHT: Yes
- Time schedule for examinations: Gestation days 0, 1, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 29. Body weight change was calculated for gestation days 0-1, 1-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-21, 21-24, 24-27, 27-29 and 1-29. Adjusted body weight (minus gravid uterus) and adjusted bodyweight change were also calculated.
FOOD CONSUMPTION AND COMPOUND INTAKE: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Time schedule for examinations: Food consumption recorded daily and reported on the corresponding body weight days.
POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 29. Each surviving female was euthanised by injection with euthanasia solution, followed by exsanguination of the femoral vessels and immediately subjected to a laparohysterectomy.
- Organs examined: Does were subjected to a complete necropsy. Special emphasis was placed on structural abnormalities or pathologic changes that may have influenced pregnancy. - 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 - 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:
- All parental in-life data, gravid uterine weights, corpora lutea/doe, total implantations/doe, litter size/doe, viable foetuses/doe, total number of resorptions/doe, number of early resorptions/doe and number of late resorptions/doe were assessed using group pair-wise comparisons. Levene's test was used to assess homogeneity of group variances. If Levene's test was not significant (p≥0.01), a pooled estimate of variance (Mean Square Error) was computed from a one-way analysis of variance (ANOVA) and utilised by a Dunnett's comparison of each treatment group with the control. If the Levene's test was significant (p<0.01), then Welch's t-test was used with a Bonferroni correction for comparisons with the control group. All endpoints were analysed using two-tailed tests.
Foetal sex ratio (% males/litter), % preimplantation loss and % postimplantation loss were analysed using Arcsin-Square-Root Transformation. Percent values were transformed using the arcsin of the square root and analysed in accordance with the group pair-wise comparisons.
Pregnancy index, malformations and variations were all evaluated using Fisher’s exact test. An overall test for association between response and treatment was performed. If this test was significant (p<0.05) and there were more than two groups, then each treatment group was compared to the control group. All endpoints were analysed sing two-tailed tests. Overall testing and follow-up pair-wise testing was conducted for the control and all treatment groups that had sufficient sample size (n≥3).
Mean foetal bodyweights were analysed by covariate analysis by comparing treatment groups for each endpoint (mean of foetal bodyweights per female). The covariate was litter size. Each treatment satisfying the sample size assumption was compared to the control using Dunnett's test under the analysis of covariance model. Endpoints were analysed using two tailed tests.
The number of non-viable foetuses/doe was analysed by descriptive statistics. - Indices:
- - Viable foetuses
- Postimplantation loss = ((No. implantations - No. viable foetuses) / No. implantations) x 100
- Preimplantation loss = ((No. corpora lutea - No. implantations) / No. corpora lutea) x 100
- Pregnancy index = (No. pregnant females - No. females with evidence of mating) x 100
- Foetal sex ratio - Historical control data:
- A large database of historical control data for the rabbit was available for comparison.
- Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- - In the 30 and 60 mg/kg bw/day dose groups, no clinical effects were noted at post-dose examination. There was a slight decrease in defecation in the 30 and 60 mg/kg bw/day dose groups. This generally correlated with late gestation inappetence which is common in rabbits and not considered to be test material related.
- In the 120 mg/kg bw/day group, findings attributed to the test material included 2/25 animals with decreased activity, abnormal shaped faeces in 4/25 animals, discoloured urine (orange) in 13/25 animals and thin appearance in 11/25 animals. There was also a decrease in defecation in these animals (19/25 animals) appearing from around gestation day 4 and lasting throughout gestation. The decreased defecation in this group correlated with low food consumption and was considered test material related. Brown/red material was found in the sub-cage pan of 7 animals in the 120 mg/kg bw/day. This was related to failed pregnancies in 5 of these animals (two aborted pregnancies, one early delivery and two litters with resorbing foetuses).
- No further treatment related clinical findings were observed in the 120 mg/kg bw/day group. - Dermal irritation (if dermal study):
- not examined
- Mortality:
- mortality observed, non-treatment-related
- Description (incidence):
- - At all dose levels tested, there were no effects observed on maternal survival.
- A single animal in the 30 mg/kg bw/day group died on gestation day 29 prior to euthanasia. The death of this animal was attributed to a dosing event.
- An animal in the 60 mg/kg bw/day group was noted to have difficulty breathing on gestation day 6 and was euthanised in extremis; this was also attributed to a dosing event and was not considered test material related.
- An animal in the 120 mg/kg bw/day group was found deceased on gestation day 24, apart from being noted as thin on gestation day 3, the animal was found to be clinically unremarkable thereafter. Findings at necropsy indicated that this was also the result of a dosing event.
- All other animals survived until scheduled sacrifice. - Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- - No adverse effects on bodyweight and bodyweight change were noted at 30 and 60 mg/kg bw/day.
- In the 120 mg/kg bw/day group, mean bodyweights from gestation day 6 to 29 were 5 to 7 % lower than controls and were found to be statistically significant. Statistically significant differences in bodyweight change were noted in this group when compared to controls over gestation days 3 to 6 and over the entire gestation period. These observed differences correlated with reduced food consumption and were attributed to test material administration. - Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Description (incidence and severity):
- - No adverse effects were observed at 30 and 60 mg/kg bw/day on food consumption. Throughout the entirety of gestation, food consumption in the 30 mg/kg bw/day group was found to be comparable to controls and in the 60 mg/kg bw/day group with the exception of gestation days 27 to 29. As food consumption in the 60 mg/kg bw/day group was comparable to the control group for gestation as a whole and in the absence of an effect on food consumption earlier in gestation, this was not considered to be a toxicological response to test material administration.
- In the 120 mg/kg bw/day group, the mean food consumption was 17 to 54 % lower than control values for the majority of the intervals recorded. Most of these differences were found to be statistically significant, and overall throughout the entirety of gestation food consumption was found to be 41 % lower than controls in this group. The lower food consumption in this group correlated with effects noted on bodyweight and bodyweight change and was determined to be test material related. - Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not specified
- Haematological findings:
- not specified
- Clinical biochemistry findings:
- not specified
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- no effects observed
- Description (incidence and severity):
- - At necropsy, no effect of treatment was observed at any dose level tested. The findings observed were found to be of low incidence and not related to test material administration.
- Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- not specified
- Histopathological findings: neoplastic:
- not specified
- Other effects:
- not examined
- Number of abortions:
- effects observed, treatment-related
- Description (incidence and severity):
- - One animal in the 60 mg/kg bw/day group and two animals in the 120 mg/kg bw/day group aborted. These events were preceded by maternal toxicity and were considered to be related to test material administration, but secondary to maternal toxicity.
- Pre- and post-implantation loss:
- effects observed, treatment-related
- Description (incidence and severity):
- - There were two females in the 120 mg/kg bw/day group with only resorbing foetuses in utero (100 % post implantation loss).
- At 30 and 60 mg/kg bw/day, no effect was noted on uterine implantation. In the 120 mg/kg bw/day group, a test material related effect was observed from an increase in post-implantation loss. The mean post-implantation loss was higher at 15.32 % compared to 2.09 % in controls, though this was not found to be statistically significant. - Total litter losses by resorption:
- effects observed, treatment-related
- Description (incidence and severity):
- - There were two females in the 120 mg/kg bw/day group with only resorbing foetuses in utero (100 % post implantation loss).
- At 30 and 60 mg/kg bw/day, no effect was noted on uterine implantation. In the 120 mg/kg bw/day group, the mean number of early resorptions and total resorptions were statistically higher, 1.3 and 1.4, respectively, when compared to control values of 0.1 and 0.2, respectively. - Early or late resorptions:
- effects observed, treatment-related
- Description (incidence and severity):
- - At 30 and 60 mg/kg bw/day, no effect was noted on uterine implantation. In the 120 mg/kg bw/day group, the mean number of early resorptions and total resorptions were statistically higher, 1.3 and 1.4, respectively, when compared to control values of 0.1 and 0.2, respectively.
- Dead fetuses:
- not specified
- Changes in pregnancy duration:
- effects observed, treatment-related
- Description (incidence and severity):
- One animal in the 120 mg/kg bw/day group delivered early.
- Changes in number of pregnant:
- no effects observed
- Description (incidence and severity):
- Pregnancy indices were 100, 96, 100 and 96 % in the control, 30, 60 and 120 mg/kg bw/day groups, respectively.
- Other effects:
- effects observed, treatment-related
- Description (incidence and severity):
- Mean gravid uterine weights and adjusted weight change in the low and mid dose groups were comparable to the control group. In the 120 mg/kg bw/day group, the mean adjusted weight change over the gestation period was statistically significant as an overall loss of 0.137 kg was observed compared to a 0.039 kg weight gain in controls. The mean gravid uterine weight and adjusted bodyweight in this group were comparable to mean control values.
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 30 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- clinical signs
- early or late resorptions
- food consumption and compound intake
- number of abortions
- pre and post implantation loss
- Abnormalities:
- not specified
- Fetal body weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- - No effect of the test material was observed on foetal bodyweight with administration of the test material at 30 and 60 mg/kg bw/day.
- In the 120 mg/kg/day dose group, mean foetal weights, distinguished by sex and for the combined sexes were 11 to 13 % lower than mean control values. These differences were statistically significant and considered to be a test material-related effect. - Reduction in number of live offspring:
- not specified
- Changes in sex ratio:
- no effects observed
- Description (incidence and severity):
- No effect was observed on foetal sex ratio with the administration of the test material at any dose level.
- Changes in litter size and weights:
- not specified
- Changes in postnatal survival:
- not examined
- External malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- - No effect of treatment was observed at all dose levels evaluated with respect to external examinations.
- The external malformations observed in the mid and high dose group foetuses were dissimilar, occurred at low incidence or with similar frequency as the controls. These were therefore considered to be unrelated to administration of the test material.
- No external malformations were observed in the 30 mg/kg bw/day group. - Skeletal malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- - No effect of treatment was observed in the skeletal examinations at all dose levels tested. In the 60 mg/kg bw/day group, the litter incidence of unossified sternebrae was 73.9 %; this was statistically different from the 28 % observed in controls, but just outside the maximum incidence commonly observed in the historical control data. With the absence of a similar increase in incidence in the 120 mg/kg bw/day group, this was considered to be an incidental occurrence and not test material related.
- Visceral malformations:
- effects observed, non-treatment-related
- Description (incidence and severity):
- - No effect of treatment at the dose levels evaluated was observed from the foetal visceral examinations.
- The few visceral malformations and developmental variations observed in the treated groups occurred at low incidence or with similar frequency as in controls and were considered unrelated to the test material. - Other effects:
- not examined
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 60 mg/kg bw/day
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- fetal/pup body weight changes
- Abnormalities:
- not specified
- Developmental effects observed:
- not specified
- Conclusions:
- Under the conditions of the test, the No-Observed-Effect Level (NOEL) for maternal toxicity was determined to be 30 mg/kg bw/day based on clinical findings, lower gestation bodyweights, lower bodyweight gain and lower food consumption seen at 120 mg/kg bw/day and aborted pregnancies at 60 and 120 mg/kg bw/day (secondary effects to maternal toxicity).
The NOEL for developmental toxicity was determined to be 60 mg/kg bw/day based on increases in post-implantation loss, increases in total and early resorption sites and lower foetal body weights at 120 mg/kg bw/day. At all dose levels tested, the test material was found not to be teratogenic in the rabbit. - Executive summary:
The developmental toxicity potential of the test material was investigated in the rabbit in a study performed in accordance with the standardised guidelines OECD 414 and US EPA OPPTS 870.3700 under GLP conditions.
The test material was administered to timed pregnant New Zealand White rabbits via oral gavage in corn oil from gestation day 1 to gestation day 28 at doses of 0, 30, 60 and 120 mg/kg bw/day. Observations of the animals included clinical signs, body weights and food consumption. Animals were sacrificed on gestation day 29. The does underwent ovarian and uterine examinations and necropsy. The foetuses were examined for external, skeletal and visceral malformations and variations.
No test material-related mortality was observed. At the 30 and 60 mg/kg/day dose levels, no adverse effects of treatment were observed from clinical findings, gestation body weights or body weight gain, food consumption, uterine implantation data, or foetal body weights. At the 120 mg/kg/day dose level, maternal toxicity was observed from clinical findings (decreased activity, abnormal shaped faeces, urine discoloured orange, thin appearance and decreased defecation), lower gestation body weights and low weight gain and low food consumption.
One animal at 60 mg/kg/day and two animals at 120 mg/kg/day aborted their pregnancies and one female at 120 mg/kg/day delivered early. These adverse pregnancy outcomes were considered test material related but secondary to the maternal toxicity observed in these animals and not a direct effect of treatment. At the 120 mg/kg/day dose level, additional toxicity was observed as an increase in post-implantation loss, increases in total and early resorption sites at uterine examination, and lower foetal body weights. No effect of treatment at the dose levels evaluated was observed on foetal sex ratios, foetal external, visceral, or skeletal examinations, or maternal macroscopic examinations.
Under the conditions of the test, the No-Observed-Effect Level (NOEL) for maternal toxicity was determined to be 30 mg/kg bw/day based on clinical findings, lower gestation bodyweights, lower bodyweight gain and lower food consumption seen at 120 mg/kg bw/day and aborted pregnancies at 60 and 120 mg/kg bw/day (secondary effects to maternal toxicity).
The NOEL for developmental toxicity was determined to be 60 mg/kg bw/day based on increases in post-implantation loss, increases in total and early resorption sites and lower foetal body weights at 120 mg/kg bw/day. At all dose levels tested, the test material was found not to be teratogenic in the rabbit.
- Endpoint:
- developmental toxicity
- Type of 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:
- other: Study conducted on read-across material
- Justification for type of information:
- Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3), see attached justification.
- Reason / purpose for cross-reference:
- read-across source
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 30 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Basis for effect level:
- body weight and weight gain
- clinical signs
- early or late resorptions
- food consumption and compound intake
- number of abortions
- pre and post implantation loss
- Abnormalities:
- not specified
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 60 mg/kg bw/day
- Based on:
- test mat.
- Sex:
- male/female
- Basis for effect level:
- fetal/pup body weight changes
- Abnormalities:
- not specified
- Developmental effects observed:
- not specified
Referenceopen allclose all
Table 1: Mean gestation bodyweights, bodyweight change, food consumption and gravid uterine weights
Day / Interval |
Dose Group (mg/kg bw/day) |
|||||||||||
0 |
100 |
300 |
1000 |
|||||||||
Bodyweight (g) |
Body weight Change (g) |
Food Consumption (g/animal/day) |
Bodyweight (g) |
Body weight Change (g) |
Food Consumption (g/animal/day) |
Bodyweight (g) |
Body weight Change (g) |
Food Consumption (g/animal/day) |
Bodyweight (g) |
Body weight Change (g) |
Food Consumption (g/animal/day) |
|
0 / - |
213.4 |
- |
- |
211.2 |
- |
- |
212.7 |
- |
- |
212.7 |
- |
- |
3 / 0-3 |
228.3 |
14.8 |
12.8 |
229.3 |
18.1 |
13.4 |
233.3 |
20.6** |
13.2 |
230.2 |
17.5 |
11.3* |
6 / 3-6 |
243.9 |
15.6 |
17.3 |
243.5 |
14.2 |
16.6 |
249.1 |
15.8 |
17.0 |
243.8 |
13.6 |
16.6 |
9 / 6-9 |
262.0 |
18.1 |
19.2 |
261.0 |
17.5 |
18.1 |
266.4 |
17.3 |
19.2 |
260.8 |
17.0 |
19.1 |
12 / 9-12 |
284.1 |
22.1 |
20.2 |
285.1 |
24.1 |
19.6 |
293.3 |
26.9** |
20.3 |
286.2 |
25.3* |
19.8 |
15 / 12-15 |
305.6 |
21.5 |
21.7 |
303.0 |
17.9 |
21.4 |
309.5 |
16.2 |
22.6 |
294.2 |
8.1** |
20.1 |
18 / 15-18 |
337.6 |
32.0 |
24.3 |
335.6 |
32.7 |
23.4 |
343.4 |
34.0 |
23.7 |
316.0* |
21.7** |
19.0** |
20 / 18-20 |
370.9 |
33.2 |
21.4 |
364.3 |
28.7 |
20.4 |
377.9 |
34.5 |
22.8 |
345.5* |
27.2* |
18.4* |
- / 0-20 |
|
Overall change: 157.4 |
Overall mean: 19.5 |
|
Overall change: 153.1 |
Overall mean: 18.9 |
|
Overall: 165.0 |
Overall mean: 19.7 |
|
Overall change: 133.3** |
Overall mean: 17.7** |
Adjusted Final Bodyweight (g) |
||||||||||||
20 |
296.8 |
294.9 |
305.7 |
278.6* |
||||||||
Adjusted weight Change from Day 0 (g) |
||||||||||||
20 |
83.4 |
83.7 |
92.8 |
66.4** |
||||||||
Gravid Uterine Weight (g) |
||||||||||||
20 |
74.1 |
69.4 |
72.2 |
66.9* |
||||||||
* p < 0.05
** p < 0.01
Table 2: Mean foetal bodyweights
| Dose Group (mg/kg bw/day) | Mean Bodyweight of Males (g) |
Mean Bodyweight of Females (g) |
Mean Bodyweight of Males & Females (g) |
0 |
4.29 (4.30) |
4.07 (4.08) |
4.19 (4.20) |
100 |
4.19 (4.18) |
3.96 (3.94) |
4.09 (4.07) |
300 |
4.24 (4.24) |
4.05 (4.05) |
4.15 (4.15) |
1000 |
3.94 (3.95)** |
3.73 (3.74)** |
3.83 (3.84)** |
** p < 0.01
( ) Least square mean
Table 1: Mean gestation bodyweights, bodyweight change, food consumption and gravid uterine weights
Day / Interval |
Dose Group (mg/kg bw/day) |
|||||||||||
0 |
30 |
60 |
120 |
|||||||||
Bodyweight (kg) |
Body weight Change (kg) |
Food Consumption (g/animal/day) |
Bodyweight (kg) |
Body weight Change (kg) |
Food Consumption (g/animal/day) |
Bodyweight (kg) |
Body weight Change (kg) |
Food Consumption (g/animal/day) |
Bodyweight (kg) |
Body weight Change (kg) |
Food Consumption (g/animal/day) |
|
0 / - |
3.13 |
- |
- |
3.13 |
- |
- |
3.11 |
- |
- |
3.13 |
- |
- |
1 / 0-1 |
3.19 |
0.06 |
52.04 |
3.17 |
0.04 |
52.08 |
3.15 |
0.04 |
53.04 |
3.15 |
0.03 |
49.75 |
3 / 1-3 |
3.25 |
0.06 |
150.76 |
3.25 |
0.08 |
158.08 |
3.21 |
0.06 |
143.04 |
3.17 |
0.02 |
109.29** |
6 / 3-6 |
3.31 |
0.06 |
156.20 |
3.31 |
0.06 |
159.13 |
3.28 |
0.08 |
147.16 |
3.15* |
-0.02** |
90.65** |
9 / 6-9 |
3.36 |
0.05 |
149.92 |
3.36 |
0.05 |
157.79 |
3.33 |
0.03 |
137.32 |
3.16** |
0.01 |
71.67** |
12 / 9-12 |
3.40 |
0.04 |
147.13 |
3.42 |
0.06 |
153.89 |
3.39 |
0.05 |
140.54 |
3.18** |
0.01 |
67.02** |
15 / 12-15 |
3.50 |
0.10 |
132.65 |
3.52 |
0.10 |
141.36 |
3.48 |
0.10 |
122.61 |
3.26** |
0.08 |
63.58** |
18 / 15-18 |
3.52 |
0.02 |
142.91 |
3.54 |
0.02 |
148.97 |
3.52 |
0.03 |
136.44 |
3.26** |
0.00 |
70.64** |
21 / 18-21 |
3.55 |
0.03 |
142.44 |
3.58 |
0.04 |
148.82 |
3.54 |
0.03 |
135.56 |
3.31** |
0.06 |
88.00** |
24 / 21-24 |
3.60 |
0.05 |
111.73 |
3.65 |
0.07 |
129.31 |
3.58 |
0.04 |
110.54 |
3.36** |
0.05 |
91.40 |
27 / 24-27 |
3.63 |
0.03 |
93.23 |
3.66 |
0.01 |
103.58 |
3.59 |
0.02 |
80.69 |
3.40* |
0.03 |
77.41 |
29 / 27-29 |
3.65 |
0.02 |
88.22 |
3.64 |
-0.01 |
72.42 |
3.60 |
-0.01 |
50.54* |
3.42* |
-0.01 |
59.00 |
- / 0-29 |
|
Overall change: 0.45 |
Overall mean: 132.38 |
|
Overall change: 0.47 |
Overall mean: 138.91 |
|
Overall change: 0.44 |
Overall mean: 122.66 |
|
Overall change: 0.26** |
Overall mean: 78.47** |
Adjusted Final Bodyweight (kg) |
||||||||||||
29 |
3.173 |
3.147 |
3.136 |
3.006 |
||||||||
Adjusted weight Change from Day 0 (kg) |
||||||||||||
29 |
0.039 |
0.028 |
0.010 |
-0.137** |
||||||||
Gravid Uterine Weight (kg) |
||||||||||||
29 |
0.474 |
0.483 |
0.460 |
0.428 |
||||||||
* p < 0.05
** p < 0.01
Table 2: Mean foetal bodyweights
Dose Group (mg/kg bw/day) |
Mean Bodyweight of Males (g) |
Mean Bodyweight of Females (g) |
Mean Bodyweight of Males & Females (g) |
0 |
40.91 (40.55) |
39.44 (39.23) |
40.04 (39.83) |
30 |
39.47 (39.81) |
39.95 (39.96) |
39.98 (39.99) |
60 |
37.55 (37.74) |
38.13 (38.36) |
37.93 (38.18) |
120 |
35.55 (35.40)** |
35.14 (35.11)** |
35.61 (35.58)** |
** p < 0.01
( ) Least square mean
Table 3: Summary of Mean Maternal and Developmental Observations at Uterine Observation
Endpoint |
0 mg/kg/day |
30 mg/kg/day |
60 mg/kg/day |
120 mg/kg/day |
No. Females in study |
25 |
25 |
25 |
25 |
No. Not pregnant |
0 |
1 |
0 |
1 |
Pregnancy Index (%) |
100 |
96 |
100 |
96 |
No. Died Pregnant/Euthanised Moribund |
0 |
1 |
1 |
1 |
No. Abortions |
0 |
0 |
1 |
2 |
No. Early Deliveries |
0 |
0 |
0 |
1 |
No. Females with all resorptions |
0 |
0 |
0 |
2 |
No. Females with viable foetuses at GD29 |
25 |
23 |
23 |
18 |
No. Corpora lutea (per animal) |
9.5 |
10 |
9.9 |
8.8 |
No. Implantation sites (per animal) |
8.6 |
8.9 |
9.1 |
9.1 |
% Preimplantation loss (per animal) |
9.04 |
11.31 |
7.63 |
5.64 |
No. Viable foetuses (per animal) |
8.4 |
8.7 |
8.9 |
7.8 |
Foetal sex ratio (% males per animal) |
51.2 |
53.4 |
51.8 |
49.9 |
% Postimplantation loss (per animal) |
2.09 |
4.61 |
3.06 |
15.32 |
No. Nonviable foetuses (per animal) |
0 |
0 |
0 |
0 |
Litter size (no. per animal) |
8.4 |
8.7 |
8.9 |
8.6 |
No. Total resorptions (per animal) |
0.2 |
0.3 |
0.3 |
1.4* |
No. Early resorptions (per animal) |
0.1 |
0.1 |
0.2 |
1.3* |
No. Late resorptions (per animal) |
0.1 |
0.1 |
0.0 |
0.1 |
* p < 0.05
Effect on developmental toxicity: via oral route
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- NOAEL
- 60 mg/kg bw/day
- Study duration:
- subacute
- Species:
- rabbit
Effect on developmental toxicity: via inhalation route
- Endpoint conclusion:
- no study available
Effect on developmental toxicity: via dermal route
- Endpoint conclusion:
- no study available
Additional information
Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).
In the first key study (Schroeder 2014) the developmental toxicity potential of the test material was investigated in the rabbit. The test material was administered to timed pregnant New Zealand White rabbits via oral gavage in corn oil from gestation day 1 to gestation day 28 at doses of 0, 30, 60 and 120 mg/kg bw/day. Observations of the animals included clinical signs, body weights and food consumption. Animals were sacrificed on gestation day 29. The does underwent ovarian and uterine examinations and necropsy. The foetuses were examined for external, skeletal and visceral malformations and variations.
No test material-related mortality was observed. At the 30 and 60 mg/kg/day dose levels, no adverse effects of treatment were observed from clinical findings, gestation body weights or body weight gain, food consumption, uterine implantation data, or foetal body weights. At the 120 mg/kg/day dose level, maternal toxicity was observed from clinical findings (decreased activity, abnormal shaped faeces, urine discoloured orange, thin appearance and decreased defecation), lower gestation body weights and low weight gain and low food consumption.
One animal at 60 mg/kg/day and two animals at 120 mg/kg/day aborted their pregnancies and one female at 120 mg/kg/day delivered early. These adverse pregnancy outcomes were considered test material related but secondary to the maternal toxicity observed in these animals and not a direct effect of treatment. At the 120 mg/kg/day dose level, additional toxicity was observed as an increase in post-implantation loss, increases in total and early resorption sites at uterine examination, and lower foetal body weights. No effect of treatment at the dose levels evaluated was observed on foetal sex ratios, foetal external, visceral, or skeletal examinations, or maternal macroscopic examinations.
Under the conditions of the test, the No-Observed-Effect Level (NOEL) for maternal toxicity was determined to be 30 mg/kg bw/day based on clinical findings, lower gestation bodyweights, lower bodyweight gain and lower food consumption seen at 120 mg/kg bw/day and aborted pregnancies at 60 and 120 mg/kg bw/day (secondary effects to maternal toxicity).
The NOEL for developmental toxicity was determined to be 60 mg/kg bw/day based on increases in post-implantation loss, increases in total and early resorption sites and lower foetal body weights at 120 mg/kg bw/day. At all dose levels tested, the test material was found not to be teratogenic in the rabbit.
In the second key study (Schroeder 2014), the developmental toxicity potential of the test material was investigated in the rat. The test material was administered to timed pregnant Crl:CD (SD) rats via oral gavage in corn oil from gestation day 0 to gestation day 19 at doses of 0, 100, 300 or 1000 mg/kg bw/day. Observations of the animals included clinical signs, body weights and food consumption. Animals were sacrificed on gestation day 20. The dams underwent ovarian and uterine examinations and necropsy. The foetuses were examined for external, skeletal and visceral malformations and variations.
No treatment-related effect was observed on survival. The death of one animal in each of the 300 and 1000 mg/kg/day dose groups was not considered test material related. Salivation and audible breathing were observed in the treated groups and considered a pharmacologic response to the test material. No effect of treatment at the 100 and 300 mg/kg/day dose levels was observed on gestation body weights, body weight change, or food consumption. At the 1000 mg/kg/day dose level, maternal toxicity was observed due to statistically significant changes from mean control values of the following: lower body weights on GD 18 (-6 %) and GD 20 (-7 %); lower body weight gain GD 12 to 15 (-62 %), GD 15 to 18 (-32 %), GD 18 to 20 (-18 %), and GD 0 to 20 (-15 %); and lower food consumption GD 0 to 3 (-12 %), GD 15 to 18 (-22 %), GD 18 to 20 (-14 %), and GD 0 to 20 (-9 %). A common finding in all the 1000 mg/kg/day animals only at macroscopic examination was white foci in the non-glandular portion of the stomach. Another finding included foreign material generally identified as white in colour and having the appearance of bedding was observed in 7/25 and 23/25 females in the 300 and 1000 mg/kg/day dose groups, respectively, but not observed among the control or 100 mg/kg/day animals. The reason for these animals ingesting the bedding and its toxicological significance in relation to the test material are unclear.
No effect of the test material at dose levels ≤1000 mg/kg/day was observed on pregnancy indices, uterine implantation data, foetal sex ratios, or foetal external, visceral, or skeletal examinations. Lower foetal body weights (8 % lower than controls) were observed at 1000 mg/kg/day. Thus, the No-Observed-Adverse-Effect Level (NOAEL) for maternal and developmental toxicity was 300 mg/kg/day. There were no teratogenic effects recorded in the study.
In the first supporting study (Appel, 2004), the toxicity of the test material in Wistar rats was examined using continuous administration via the diet for 13 consecutive weeks in accordance with OECD 408. In satellite groups of female rats a reproduction/developmental screening test was performed in accordance with OECD 421 to provide initial data on the possible reproductive and developmental effects of the test material. The study was performed under GLP conditions.
The main study used four groups of 10 rats/sex (13-week study) and the satellite study used four groups of 10 female rats (reproduction/developmental screening study). For both studies the control group was kept on untreated diet and three test groups received experimental diets containing 300, 1 500 and 7 500 mg/kg (ppm) of the test material. The dose levels used in both studies were selected based on the results of a preceding dose range finding study.
In the satellite study female rats were fed their respective diets beginning two weeks prior to the mating period, and continued through mating, gestation and up to PN 4 or shortly thereafter. Male rats from the main study were mated after a premating period of 10 weeks with female rats of the satellite groups which were fed the same dose of test diet.
Clinical observations, growth, food consumption, food conversion efficiency, neurobehavioural testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy, microscopic examination of various organs and tissues and assessment of various reproductive and developmental parameters were used as criteria for detecting the effects of treatment.
The calculated doses for the females receiving 300, 1500, or 7500 mg/kg test material in the diet ranged from 15.2- 25.3, 77.3-140.8, and 433.4- 684.7 mg/kg body weight/day. None of the few changes observed in clinical signs, body weight, food consumption, fertility and reproductive performance, litter data, organ weights, gross macroscopy and microscopic examination were considered treatment-related.
As no maternal toxicity or reproductive effects in the females of the satellite groups after mating with the male animals of the main study were observed at the high-dose level of this study, this dose level 7500 mg/kg diet (equivalent to 521 mg/ kg body weight/day in males and 433-685 mg/kg body weight/day for females) can be considered as a NOAEL for maternal toxicity and fertility and developmental effects.
In the second supporting study (Noda, 1992), treatment during days 7-17 of pregnancy at dosages up to 400 mg/kg bw/day did not cause any maternal toxicity and had no effects on the incidence of dead or resorbed foetuses, the number of living foetuses, the sex ratio and the body weight of living foetuses. A single foetus in the highest dose group had anury; however, no visceral or skeletal malformations were observed. The incidence of a minor skeletal variation (i.e. cervical ribs), observed with another organotin compound, was also not dose-dependently increased. The NOAELs for both maternal and developmental toxicity was therefore 400 mg/kg bw/day, the highest dose level tested.
In the third supporting study (Ema, 2001), female rats were given the test material by gastric intubation at 0, 56, 226 or 903 mg/kg on days 0–3 or 4–7 of pregnancy. Female rats were sacrificed on day 20 of pregnancy and fetuses were examined for number, abnormality, mortality and weight. The maternal body weight gain and food consumption during the administration period was significantly decreased after administration of test substance at 903 mg/kg on days 0–3 or 4–7 of pregnancy. The pregnancy rate in the treated groups was comparable to the control value, regardless of the days on which test material was given. The incidence of pre-implantation embryonic loss was not significantly affected after administration of test material on days 0–3 or 4–7. In females having implantations, the numbers of corpora lutea, implantations, and live foetuses and the incidences of pre- and post-implantation loss in the groups given test material on days 0–3 were comparable to the controls. Although a significant increase in the incidence of post-implantation loss was observed after administration of test material on days 4–7 at 56 mg/kg, this change was small and inconsistent across doses and seems unlikely to be toxicologically significant. A significant decrease in weight of female foetuses was found after administration of test material at 903 mg/kg on days 0–3 or 4–7. It could be concluded that treatment during early pregnancy is maternally and developmentally toxic at 903 mg/kg.
In the fourth supporting study (Ema, 1995), higher dosages (1000, 1500 and 2000 mg/kg bw) were administered on days 7 and 8 of gestation. Five out of the 11 females treated at 1500 mg/kg bw/day and all 6 females treated at 2000 mg/kg bw/day died approximately 2 days after beginning treatment. Other signs of maternal toxicity, like body weight loss during days 7-9 and reduced body weight gain for the entire gestation period, as well as reduced adjusted weight gain, were noted in females treated at 1500 and 1000 mg/kg bw/day. Although the foetal weight in the 1500 mg/kg bw/day group was significantly decreased, no increases in the incidence of post implantation loss was recorded at either 1500 or 1000 mg/kg bw/day. Although internal and skeletal malformations were observed in a few foetuses of the treated groups, the incidence was not statistically significantly different from the controls. No NOAEL for maternal toxicity could be determined in this study, and 1000 mg/kg bw/day was considered a LOAEL for maternal effects. Based on the reduced pup weight observed at the maternally toxic dose of 1500 mg/kg bw/day, the NOAEL for developmental effects was 1000 mg/kg bw/day.
Justification for classification or non-classification
In accordance with points 3.7.2.3 and 3.7.2.4 of Annex II of Regulation EC 1272/2008, a thorough assessment on the appropriate classification for developmental toxicity of the test material under CLP, with particular respect to the results of the key rabbit study was performed including detailed review of individual pregnancy outcomes which were correlated with maternal findings in order to assess the influence of maternal toxicity to pregnancy outcome.
Based on the weight of evidence of the available developmental toxicity data, it was concluded that there is convincing evidence that all effects on pregnancy in the available studies are secondary and directly attributable to maternal toxicity.
Therefore the test material is not classified for reproductive and developmental toxicity according to Regulation EC no.1272/2008.
Additional information
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
