Registration Dossier

Diss Factsheets

Administrative data

Description of key information

Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).

Repeated oral toxicity

The NOAEL was determined to be 1500 mg/kg diet (equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females).

Repeated inhalation toxicity

The NOAEL was determined to be 16.18 mg test material/m³ (7.17 mg Sn/m³).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Referenceopen allclose all

Endpoint:
sub-chronic toxicity: oral
Remarks:
combined repeated dose and reproduction / developmental screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20 December 2002 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 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)
Deviations:
yes
Remarks:
minor deviations which did not affect the validity of study.
Qualifier:
according to guideline
Guideline:
other: OECD Guideline 421 (Reproduction/Developmental Toxicity Screening Test)
GLP compliance:
yes
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ORGANISMS:
- Species: Albino rats
- Strain: Wistar outbred (Crl:(WI)WU BR)
- Age at study initiation: approximately 7 weeks old males and females (13-14 weeks age of females in the satellite study)
- Weight at study initiation:  135.0 - 167.1 g (mean 150.7 g) for males;  112.6 - 148.5 g (mean 126.2 g) for females (body weights for females in the satellite groups at the start of treatment ranged from 194.2 - 229.6 g (mean 208.5 g).

- 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

Upon arrival animals were put in a quarantine room and were given time to acclimatise 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.

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.

The room was ventilated with about 10 air changes per hour and was maintained at a temperature of 22 ± 3°C at a relative humidity of 30 - 70%. Lighting was artificial with 12-hour light and dark cycles.

Feed and drinking water were provided ad libitum. A commercial rodent diet was provided.
Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
ADMINISTRATION / EXPOSURE:
- Duration of exposure: 14 days or 13 consecutive weeks, dose-range finding study and subchronic study, respectively
- Type of exposure: via the diet
- Doses: 0, 300, 1500 and 7500 mg/kg diet for subchronic study

SATELLITE GROUPS AND REASONS THEY WERE ADDED: Four satellite groups of female rats were added. The objective was to provide initial data on the possible reproductive and developmental effects of the test material after oral administration.
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.

The homogeneity, stability, and achieved concentration (content) of the test material in 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
Main sub-chronic study: 13 weeks
Frequency of treatment:
Continuous (in diet)
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 animals per sex per dose
13-week study: 10 animals per sex per dose
Control animals:
yes, plain diet
Details on study design:
ADMINISTRATION / EXPOSURE:
- Duration of exposure: 14 days or 13 consecutive weeks, dose-range finding study and sub-chronic study, respectively
- Type of exposure: via the diet
- Dose-range finding study: 0, 100, 300, 1000, 5000 mg/kg diet
- 13 week sub-chronic study doses: 0, 300, 1500 and 7500 mg/kg diet
Positive control:
None
Observations and examinations performed and frequency:
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. Thereafter, body weights were recorded once weekly. In the dose range finding study, body weights were recorded twice weekly. Furthermore, all 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 by weighing the feeders (in g/animal/day). The efficiency of food utilisation was calculated and expressed in g weight gain/g food consumed. Food consumption of male rats of the main study was not measured in weeks 10 (all animals) and 11 (some animals), because this measurement was hampered by the mating procedure (male rats of the 13-week study were  used to mate with the female rats from the satellite group).
- 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 the test material, the food consumption and the mean body weight in the period for which the intake of the test material is calculated.
- Neurobehavioural testing: arena testing, functional observational  battery (FOB) and motor activity assessment.
- Ophthalmoscopic examination: observations made prior to the start of the treatment in all animals and towards the end of the treatment period in all surviving animals of the control and 7500 mg/kg groups. Eye examinations were carried out using an ophthalmoscope after induction of mydriasis by a solution of atropine sulphate.
- Haematology: at necropsy at the end of treatment, after overnight fasting, blood samples were taken from the abdominal aorta of all  surviving animals. Determinations carried out included: haemoglobin, packed cell volume, red blood cell count, reticulocytes, total white blood cell count, differential white blood cell count, prothrombin time, thrombocyte count. The mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were calculated.
- Biochemistry: at necropsy at the end of treatment, after overnight fasting, blood samples were taken from the abdominal aorta of all surviving animals. Measurements made included alkaline phosphatase activity (ALP), aspartate aminotransferase activity (ASAT), alanine aminotransferase activity (ALAT), gamma glutamyl transferase activity (GGT), total protein, albumin, albumin to globulin ratio (A/G), urea, creatinine, total bile acid, bilirubin (total and direct), cholesterol  (total), triglycerides, phospholipids, Ca, Na, K, Cl, inorganic phosphate, fasting glucose.
- Urinalysis and renal concentration test: Shortly before the end of the treatment (days 86-87), all animals were deprived of water for 24 hours  and of food during the last 16 hours of this period. During the last 16 hours of deprivation, the rats were kept in metabolism cages (one rat per cage) and urine was collected. The concentrating ability of the kidneys was investigated by measuring the volume and density of the individual samples. The determinations carried out with the urine collected in the renal concentration test included: appearance of the urine, glucose, pH, occult blood, ketones, protein, bilirubin, urobilinogen, microscopy of  the sediment.
Sacrifice and pathology:
- All animals were subjected to a complete gross necropsy. In the dose-range finding study, the animals were killed after 14 days of treatment. In week 14, the animals of the 13-week study were killed on a number of successive working days so that the average time of killing was approximately the same for each group. The animals were killed by exsanguination from the abdominal aorta under anaesthesia.

ORGANS EXAMINED AT NECROPSY:
- Macroscopic: organs weighed included adrenals, brain, epididymides, heart, kidneys, liver, ovaries, spleen, testes, thymus, thyroid (with parathyroids), uterus.  
- Histopathological examination was performed on tissues and organs of all animals of the control and treatment groups and included adrenals, aorta, brain (brain stem, cerebrum, cerebellum), caecum, colon, epididymides, eyes, GALT (gut associated lymphoid tissue, including Peyer's patches), heart, kidneys, liver, lungs, mammary gland (females), mesenteric lymph nodes, nerve-peripheral (sciatic), oesophagus, ovaries, pancreas, parathyroid, pituitary, prostate, rectum, skin (flank), small intestine (duodenum, ileum, jejunum), spinal cord (at 3 levels), spleen, sternum with bone marrow, stomach (glandular and non-glandular), sublingual salivary glands, submaxillary salivary glands, testes, thymus, thyroid, trachea/bronchi, urinary bladder, uterus (with cervix), and all gross lesions.
Other examinations:
A 14-day dose range finding study was performed to determine the dose levels to be used in the main study. For this purpose 4 animals per sex per dose were administered the test material daily via the diet at dose levels of 0, 100, 300, 1000, 5000 mg/kg diet. In the dose range finding study, the animals were examined for clinical signs, mortality, body weights, food consumption and gross necropsy (adrenals, kidneys, liver, spleen, testes and ovaries).
Statistics:
- Test material analysis:
Homogeneity: one way analysis of variance (Anova) using the sample location 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 was considered to represent the achieved concentration.
- Body weight: one way analysis of covariance (covariate: body weight on  day 0) followed by Dunnett's multiple comparison tests.
- Neurobehavioral observations: parameters assessed during functional  observations were measured on different measurement scales. Continuous measures were analysed by analysis of variance techniques and other parametric tests where appropriate. Rank and categorical data were analysed non-parametrically. Motor activity data were analysed using analysis of variance techniques.
- Food consumption and food efficiency: one way analysis of variance (Anova) followed by L.S.D. tests.
- Red blood cell and clotting potential variables, total white blood cell counts, absolute differential white blood cell counts, clinical chemistry values, volume and density of the urine, organ weight: one way analysis of variance (Anova) followed by Dunnett's multiple comparison tests.
- Relative differential white blood cell counts, urinary parameters  except volume and density: Kruskal-Wallis non-parametric Anova followed  by Mann-Whitney U-tests.
- Histopathological changes: Fisher's exact probability test. All tests were two-sided.  Probability values of p < 0.05 were considered  significant.
Clinical signs:
no effects observed
Description (incidence and severity):
No treatment related findings were observed.
Mortality:
no mortality observed
Description (incidence):
No mortality occurred.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Body weights were similar among the groups in males and females throughout the study.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
- Food consumption: Food consumption was slightly higher in males of the 7500 mg/kg group. This difference was statistically significant on days: 21, 35, 49 and 63. Furthermore, an occasional statistically significant difference was seen in the 300 and 1500 mg/kg groups. Food consumption in females was similar among the groups throughout the study. An occasional statistically significant difference was seen in all dose groups.
Overall intake of the test material for the 300, 1500 and 7500 mg/kg groups was 19, 96 and 521 mg/kg bw/day, respectively for males and 20, 101 and 533 mg/kg bw/day, respectively for females.
Analysis of the test material in diet samples revealed that the test material dose was close to the nominal level for all diets. Mean measured concentrations ranged from 93 to 109 % of nominal concentrations.
Food efficiency:
effects observed, treatment-related
Description (incidence and severity):
- Food conversion efficiency: Similar among the groups in males and females throughout the study. An occasional significant difference was seen in males.
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
no effects observed
Description (incidence and severity):
No treatment-related ocular changes were observed.
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
The number of reticulocytes was statistically significantly increased in males of the 7500 mg/kg group. Mean corpuscular haemoglobin was statistically significantly decreased in females of the 7500 mg/kg group. Prothrombin time was statistically significantly decreased in males and females of the 7500 mg/kg group. The total numbers of white blood cells and lymphocytes were statistically significantly increased in males of the 7500 mg/kg group.
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
In males of the 7500 mg/kg group, ALP, ASAT, GGT, A/G ratio, bile acids, triglycerides, phospholipids and potassium were statistically significantly increased and sodium was statistically significantly decreased. In females of the 300 mg/kg group, ASAT was statistically significantly increased. In females of the 7500 mg/kg group, triglycerides were statistically significantly increased.
Urinalysis findings:
effects observed, treatment-related
Description (incidence and severity):
Urinary pH was higher in males of the 1500 and 7500 mg/kg groups. Further semi-quantitative and microscopic urinary observations were similar among the groups.
- Renal concentration test: Urinary density in males of the 1500 mg/kg group was statistically significantly lower relative to the control group. This change was not considered related to the treatment, in the absence of a dose-response relation. No other changes were observed in urinary volume and density among the groups.
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
The results of the neurobehavioral observations and motor activity assessment did not indicate any neurotoxic potential of the test material.
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
The absolute (males) and relative (males and females) liver weights were statistically significantly increased in the 7500 mg/kg group. No other statistically significant differences were observed among the groups.
Gross pathological findings:
no effects observed
Description (incidence and severity):
No treatment related changes were observed.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
No treatment related changes were observed.
Histopathological findings: neoplastic:
no effects observed
Description (incidence and severity):
No treatment related changes were observed.
Other effects:
not examined
Details on results:
NOAEL: Although not accompanied by histopathological findings, the changes in haematology, clinical chemistry and liver weights are indicative of liver damage. On the basis of the increases in ASAT, GGT, bile acids, triglycerides and relative liver weights in animals of the 7500 mg/kg group, the No Observed Adverse Effect Level (NOAEL) in the  sub-chronic toxicity study was placed at 1500 mg/kg diet. This level was equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day for females.

OTHER: RANGE FINDING STUDY Dietary doses of 100, 300, 1000, and 5000 mg/kg feed (ppm) were administered for 14 days. No clinical abnormalities were observed. Body weights were not significantly different among the groups. Food consumption and food conversion efficiency were similar among the control and treated groups. Absolute and relative organ weights (ovaries, testes, adrenals, kidneys, spleen and liver) were not significantly different among the groups, except for the relative liver weight of the females of the 5000 mg/kg group which was slightly (ca. 8 %) but significantly increased. Macroscopic examination at necropsy did not reveal any treatment-related changes. Dietary exposure of the test materialup to 5000 mg/kg diet was well tolerated by rats for 14 days. The only possible treatment-related change was a  slight, but significant increase in liver weights of females of the 5000 mg/kg group. Dose for the main subchronic (13 -week) and satellite studies were chosen as 300, 1500, and 7500 mg/kg diet based on the dose-range finding study.
Key result
Dose descriptor:
NOAEL
Effect level:
1 500 mg/kg diet
Sex:
male/female
Basis for effect level:
other: The NOAEL of 1500 mg/kg diet was equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females.
Key result
Dose descriptor:
LOAEL
Effect level:
7 500 mg/kg diet
Sex:
male/female
Basis for effect level:
clinical biochemistry
haematology
organ weights and organ / body weight ratios
other: Based on increases in liver enzymes, bile acids, triglycerides in blood, and relative liver weights in animals at the 7500 mg/kg diet group (equivalent to 521-533 mg/kg/day)
Critical effects observed:
not specified
Conclusions:
Although not accompanied by histopathological findings, the changes in haematology, clinical chemistry, and liver weights are indicative of liver damage. On the basis of increases in ASAT, GGT, bile acids, triglycerides, and relative liver weights in animals of the 7500 mg/kg diet group, the NOAEL in this subchronic toxicity study was placed at 1500 mg/kg diet. This level is equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females.
Executive summary:

The toxicity of the test material was examined in Wistar rats using continuous administration in the diet for 13 consecutive weeks. In satellite groups of female rats, a reproduction/developmental screening study was also performed. The repeated dose toxicity study was conducted in accordance with the standardised guideline OECD 408, under GLP conditions.

During the study, four groups of 10 rats per sex per group received diets containing 300, 1500, and 7500 mg/kg (ppm) of the test material in the feed. The control group was kept on an untreated diet.

These dose levels were based on the results of a preceding dose-range finding study that used doses of 0, 100, 300, 1000, and 5000 mg/kg diet. Clinical observations, growth, food consumption, food conversion efficiency, neurobehavioral testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy, histopathology examination were used for detection of toxicity.

The calculated intake values for the three test groups receiving 300, 1500, and 7500 mg/kg diet were 19, 96, and 521 mg/kg bw/day for males and 20, 101, and 533 mg/kg bw/day in females. A treatment-related increase in urinary pH was seen in males of 1500 and 7500 mg/kg groups, but this change was not considered toxicologically relevant. The males of the 7500 mg/kg group showed significant increases in reticulocytes, total white blood cells, lymphocytes, ALP, ASAT, GGT, bile acids, triglycerides, potassium, and absolute and relative liver weights, and decreased prothrombin time. In females of the 7500 mg/kg group, triglycerides and relative liver weights were significantly increased and prothrombin time was decreased. These changes were considered treatment-related and toxicologically relevant. No other treatment-related changes that were significant were observed in the high dose group, or the lower groups.

Although not accompanied by histopathological findings, the changes in haematology, clinical chemistry, and liver weights are indicative of liver damage. On the basis of increases in ASAT, GGT, bile acids, triglycerides, and relative liver weights in animals of the 7500 mg/kg diet group, the NOAEL in this subchronic toxicity study was placed at 1500 mg/kg diet. This level is equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females.

Endpoint:
sub-chronic toxicity: oral
Remarks:
combined repeated dose and reproduction / developmental screening
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:
1 500 mg/kg diet
Sex:
male/female
Basis for effect level:
other: The NOAEL of 1500 mg/kg diet was equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females.
Key result
Dose descriptor:
LOAEL
Effect level:
7 500 mg/kg diet
Sex:
male/female
Basis for effect level:
clinical biochemistry
haematology
organ weights and organ / body weight ratios
other: Based on increases in liver enzymes, bile acids, triglycerides in blood, and relative liver weights in animals at the 7500 mg/kg diet group (equivalent to 521-533 mg/kg/day)
Critical effects observed:
not specified
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
96 mg/kg bw/day
Study duration:
subchronic
Species:
rat
System:
hepatobiliary
Organ:
liver

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Referenceopen allclose all

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
03 September 1985 to 01 October 1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Reason / purpose for cross-reference:
other: read-across target
Qualifier:
no guideline followed
Principles of method if other than guideline:
This study was designed to assess the toxic effects of the test material when administered by inhalation as an vapour/aerosol to Sprague-Dawley derived rats (35/sex/group) for six hours per day, five days per week, for four weeks at target concentrations of 1, 10 and 30 mg/m³
GLP compliance:
yes (incl. QA statement)
Remarks:
Statement of compliance with US EPA's GLP Standards and applicable Standard Operating Procedures with some exceptions noted.
Limit test:
no
Species:
rat
Strain:
other: CD (Sprague-Dawley derived)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at initiation of exposure: approx. 9 weeks old (males and females)
- Initial body weights: 278 - 337 g (males, mean = 308) and 160 - 204 g (females, mean = 182).
- Acclimation: Animals were acclimated for 4 weeks and were examined by the staff veterinarian. Animals considered unsuitable for the study were excluded prior to random selection for group assignment.
- Housing:
During non-exposure periods animals were doubly-housed in suspended stainless steel wire mesh cages during the first week of acclimation and then individually housed during the rest of the acclimation period and all non-exposure periods.
During exposure periods: Animals were doubly-housed in similar cages when the number of animals was even and any remaining odd animal was housed individually. Chamber temperature ranged between 21 - 30°C and chamber RH between 44 - 100%.
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature: 67 - 76°F
- Humidity: 30 - 70%
- Photoperiod: 12 hour light/dark cycle (7 am to 7 pm)
Route of administration:
inhalation
Type of inhalation exposure:
whole body
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
>= 0.98 - <= 1.7 µm
Remarks on MMAD:
MMAD / GSD: The MMAD were as follows:
Group I (control): N/A
Group II: 0.98 microns
Group III: 1.7 microns
Group IV: 1.5 microns
Details on inhalation exposure:
- The test material was administered as a vapour/aerosol to male and female CD (Sprague-Dawley derived) rats, via inhalation (administered in the breathing zone of the animals).   
- Target exposure levels: 0 (control), 1, 10, and 30 mg/m³. Exposure levels were selected on the basis of multiples of the current TLV at the time.
- The stainless steel and glass chambers in which the animals were exposed had a total volume of 1 m³ with an effective volume of 760 L. The airflow rates in groups I-IV were 205-209 L/min, air change was 4.8-4.9 min, and 99 % equilibrium time was 22.0-22.5 min.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- Air samples from all exposure chambers were collected (via impinger) at least 4 times over the test period. Additionally, distribution samples (i.e., one at the top and one at the bottom of the chamber) were collected from the test material exposure chambers over the course of the exposure period.
- Samples were sent to the sponsor for analysis by atomic absorption spectroscopy (AAS). Particle size distribution measurements were made weekly over the exposure period.
- Mean measured (target) exposure concentrations were 1.33 (1.0), 7.17 (10), and 9.54 (30) mg Sn/m³ (ca. 2.4, 23.8 and 71.3 mg test material/m³ target conc). The median particle diameter in the exposure chambers ranged from 0.98-1.7 µm. The particulate level in the low concentration exposure chamber (1 mg/m³) was comparable to that found in room air, indicating the test material was respirable to the rat.
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
Daily, 6 hours/day, 5 days/week
Total 20 exposures/sex/group
Dose / conc.:
1 mg/m³ air
Remarks:
Target concentration
Dose / conc.:
10 mg/m³ air
Remarks:
Target concentration
Dose / conc.:
30 mg/m³ air
Remarks:
Target concentration
No. of animals per sex per dose:
35 per sex per dose
Control animals:
yes, concurrent no treatment
Details on study design:
- Post-exposure recovery period: 0 weeks (15 animals/sex/dose), 2 weeks (10 animals/sex/dose), or 4 weeks (10 animals/sex/dose).
- The test material concentrations were calculated from the target tin (Sn) concentrations using the conversion factor [282.17/118.69] consisting of the molecular weights of the test material and Sn, respectively. All measured Sn was attributed to the test material.
Positive control:
None
Observations and examinations performed and frequency:
In-life observations:
- For mortality and gross signs of toxic effects - twice daily, once in the morning and once in the afternoon.
- Animals underwent physical examination pre-test and weekly thereafter.  
- Ophthalmoscopic examinations were performed pre-test and on weeks 5, 7, and 8.
- Body weights were recorded prior to testing, weekly during exposure, and prior to sacrifice (after fasting).  
Sacrifice and pathology:
- After 4 weeks exposure, 10 animals/sex/group were sacrificed and subjected to clinical study, postmortem examination, organ weight determination, and histopathological evaluation. An overnight urine sample was collected from an additional 5 animals/sex/group. These animals were then sacrificed and selected tissues (blood, lungs, liver, kidneys and brain) were removed and sent to the sponsor for assay. No postmortem examinations of these animals were conducted at the test laboratory.
- The remaining animals were retained for a 2- or 4-week recovery period. After the 2- and 4-week recovery periods, 10 animals/sex/group were sacrificed. Five animals/sex/group underwent clinical study, postmortem  examination, organ weight determination, and histopathological evaluation (when visibly abnormal organs were noted) at the test laboratory. The remaining 5 animals/sex/group were processed as described previously and sent to the sponsor for assay.
- Sacrifice method: Exsanguination under ether anaesthesia.
Other examinations:
- Blood samples were obtained from fasted animals, and separated into two aliquots for haematology and clinical chemistry.
- Urinalysis was also performed.
Statistics:
Body weights, haematology and clinical chemistry parameters, organ weights and organ/body weight ratios were analysed. Mean values of all treated groups were compared to control at each time interval.
Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Physical observations, including mucoid nasal discharge, rales, lacrimation, salivation, rough coat, abdominal distension (males), ano-genital staining, and fur discolouration, were observed primarily in the high-exposure group (30 mg/m³). These symptoms reduced during the recovery period.
Mortality:
mortality observed, treatment-related
Description (incidence):
- Three male rats and one female rat in the high exposure group (30 mg/m³) died during exposure. The deaths occurred after 13-15 days of exposure and were considered test material-related.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Mean body weights of male and female rats in the high-exposure group (30 mg/m³) were significantly lower than controls during all (male) or part (females) of the 4-week exposure period. The differences in animal weights (i.e., treated vs. control) decreased during the recovery period.
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:
no effects observed
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
- Post-exposure (pre-recovery) haematology data indicated slight to sometimes-significant differences from the control group. In the high-exposure group (30 mg/m³) these included increased mean haemoglobin values (males and females), increased mean erythrocyte counts (males and females), and increased mean haematocrit values (females). Female rats in all exposure groups exhibited increased mean erythrocyte counts. Differences from controls were slight, though sometimes significant.
- Haematology results in female rats in the recovery groups were comparable to controls. Male rats in the recovery groups exhibited increased mean erythrocyte counts (high dose group - 2 weeks recovery) and increased haematocrit, haemoglobin, and erythrocyte counts (mid and high dose group - 4 weeks recovery).
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Necropsy results reported primarily involved lung tissue. Observations related to exposed males and females included increased discolouration, amorphous material in lungs (potential test material or hydrolysis product), alveolar oedema (dose-related), peribronchial lymphoid cell accumulation, perivascular lymphoid cell infiltrate, extravasated alveolar erythrocytes (males only, dose-related), and accumulation of alveolar macrophages and neutrophilic infiltrates.
- The lesions and their severity scores represent the expected response of pulmonary tissue to introduction of a foreign and known corrosive material. Low-, mid- and high-dose males and females had increased lesion mean severity scores for amorphous material in their lungs compared to controls. The no-effect-level would be expected to be < 1 mg Sn/m³ (< 2.4 mg test material/m³).
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Other effects:
effects observed, treatment-related
Description (incidence and severity):
Skin sections from high-dose males and females showed epidermal acanthosis and hyperkeratosis.
Key result
Dose descriptor:
NOAEC
Effect level:
< 3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
Key result
Dose descriptor:
LOAEC
Effect level:
3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
other: local effects (microscopic findings in lung). 3 mg/m³ (test material) = 1.33 mg Sn/m³
Key result
Dose descriptor:
NOAEC
Effect level:
16.18 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
other: Systemic effects. Mortality and several clinical signs were observed at 21.53 mg/m³ (test material). 16.18 mg/m³ (test material) = 7.17 mg Sn/m³
Critical effects observed:
not specified

Table 1 : Mean Body Weight Values

Sex

Dose (mg/m³)

Exposure period

Recovery period

W0

W1

W2

W3

W4

W5

W6

W7

W8

M

0

308

+/-13

342

+/-18

367

+/-20

388

+/-21

405

+/-27

422

+/-30

438

+/-34

463

+/-32

480

+/-35

M

1

308

+/-13

344

+/-18

353*

+/-20

378

+/-23

398

+/-26

417

+/-30

437

+/-37

441

+/-38

455

+/-36

M

10

308

+/-14

339

+/-17

356

+/-20

376

+/-23

398

+/-27

419

+/-29

444

+/-30

470

+/-41

483

+/-43

M

30

307

+/-13

331*

+/-15

346**

+/-17

354**

+/-19

376**

+/-23

394*

+/-25

425

+/-29

451

+/-41

467

+/-41

F

0

182

+/-11

240

+/-12

222

+/-14

237

+/-14

248

+/-15

261

+/-19

261

+/-19

271

+/-21

277

+/-23

F

1

182

+/-10

204

+/-11

218

+/-12

236

+/-13

248

+/-14

254

+/-16

263

+/-17

266

+/-16

276

+/-18

F

10

183

+/-11

229**

+/-15

218

+/-15

233

+/-16

246

+/-17

248

+/-18

256

+/-19

262

+/-21

268

+/-20

F

30

182

+/-10

198

+/-13

214

+/-14

227*

+/-15

235**

+/-17

243*

+/-18

254

+/-21

259

+/-22

266

+/-19

*, ** results statistically significant (*p < 0.05, **p < 0.01)

Table 2 : Mean Haematology Values – Week 5

Sex

Dose (mg/m³)

HGB (g/dl)

HCT (%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

17.3

+/-0.5

40

+/-1

7.65

+/-0.21

9.76

+/-1.59

1.9

+/-0.4

13.8

+/-3.4

M

1

17.5

+/-0.9

40

+/-2

7.66

+/-0.41

9.78

+/-0.84

1.7

+/-0.4

13.5

+/-4.2

M

10

18.2

+/-1.6

40

+/-1

7.75

+/-0.36

9.81

+/-1.18

2.4

+/-0.6

13.3

+/-2.7

M

30

18.0

+/-0.7

40

+/-2

7.91

+/-0.44

9.55

+/-1.25

1.9

+/-0.7

13.8

+/-3.4

F

0

16.2

+/-0.5

37

+/-1

6.79

+/-0.20

10.72

+/-2.08

2.4

+/-0.5

9.0

+/-1.9

F

1

16.7

+/-0.5

39*

+/-1

7.13*

+/-0.19

10.21

+/-1.64

2.2

+/-0.6

10.4

+/-2.4

F

10

16.8

+/-0.6

39

+/-2

7.06*

+/-0.33

9.69

+/-1.76

1.9

+/-0.4

11.4

+/-2.5

F

30

17.4**

+/-0.5

40**

+/-1

7.33**

+/-0.21

9.92

+/-0.76

2.6

+/-0.8

11.5

+/-3.5

*, ** results statistically significant (*p < 0.05, **p < 0.01)

HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Table 3 : Mean Haematology Values – Week 7

Sex

Dose (mg/m³)

HGB

(g/dl)

HCT

(%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

16.3

+/-0.3

46

+/-1

7.25

+/-0.23

11.39

+/-1.21

1.1

+/-0.3

13.6

+/-3.6

M

1

16.7

+/-0.5

48

+/-1

7.65

+/-0.27

9.76

+/-1.28

1.2

+/-0.4

15.6

+/-3.6

M

10

16.9

+/-0.6

48

+/-3

7.61

+/-0.22

11.11

+/-1.29

1.0

+/-0.4

13.4

+/-2.8

M

30

16.8

+/-0.5

47

+/-2

7.73*

+/-0.28

10.05

+/-1.34

0.9

+/-0.3

14.0

+/-4.4

F

0

16.4

+/-0.2

46

+/-2

6.85

+/-0.29

10.57

+/-0.62

0.9

+/-0.3

8.7

+/-1.1

F

1

16.5

+/-0.5

48

+/-2

7.11

+/-0.21

9.82

+/-1.28

0.8

+/-0.3

10.8

+/-3.1

F

10

16.6

+/-0.3

48

+/-1

7.18

+/-0.26

10.34

+/-1.34

0.7

+/-0.2

9.1

+/-1.3

F

30

16.9

+/-0.2

49

+/-1

7.24

+/-0.19

11.62

+/-2.58

0.8

+/-0.4

9.9

+/-1.2

*, ** results statistically significant (*p < 0.05, **p < 0.01)

HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Table 4 : Mean Haematology Values – Week 9

Sex

Dose (mg/m³)

HGB

(g/dl)

HCT

(%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

15.9

+/-0.3

46

+/-1

7.43

+/-0.34

9.59

+/-1.77

0.7

+/-0.3

12.8

+/-1.9

M

1

16.1

+/-0.4

47

+/-1

7.58

+/-0.25

9.75

+/-1.38

0.7

+/-0.2

15.3

+/-2.3

M

10

16.9*

+/-0.7

48

+/-3

7.75

+/-0.39

10.97

+/-2.00

0.8

+/-0.4

13.7

+/-1.0

M

30

17.2**

+/-0.7

49*

+/-1

7.60

+/-0.43

9.43

+/-1.19

0.5

+/-0.2

13.3

+/-3.5

F

0

16.5

+/-0.2

48

+/-1

7.19

+/-0.19

9.65

+/-1.43

0.7

+/-0.2

9.7

+/-3.0

F

1

16.5

+/-1.3

48

+/-4

7.32

+/-0.68

9.16

+/-0.86

0.5

+/-0.2

8.9

+/-1.4

F

10

16.0

+/-1.5

46

+/-5

6.96

+/-0.60

9.09

+/-1.22

0.6

+/-0.2

8.6

+/-1.3

F

30

16.4

+/-1.6

48

+/-5

7.22

+/-0.48

9.37

+/-0.95

0.7

+/-0.2

9.9

+/-2.9

*, ** results statistically significant (*p < 0.05, **p < 0.01)

+/- HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Conclusions:
Under the conditions of the study the LOEC for local effects (microscopic findings in lungs) was 3.00 mg test material/m³ (1.33 mg Sn/m³).
For the systemic effect, the NOAEL was 16.18 mg test material/m³ (7.17 mg Sn/m³). Mortality and several clinical signs were observed at 21.53 mg/m³. As the mode of action of the test material's apparent toxicity seen in the repeat dose inhalation study is not deemed to be as a result of systemic toxic effects as a result of inhalation, but rather the test materials particular mode of action (corrosive effects) it is proposed that the test material is not classified for repeated toxicity.
Executive summary:

This study was designed to assess the toxic effects of the test material when administered by inhalation as a vapour/aerosol to Sprague-Dawley derived rats for six hours per day, five days per week, for four weeks at target concentrations of 1, 10 and 30 mg/m³. Control animals received house-supply air only while in chamber.

After four weeks of exposure (week 5), up to 15 animals/sex/group were sacrificed. The first 10 animals/sex/group were pre-designated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations (Groups I and IV animals only). An overnight urine sample was collected on the remaining 5 animals/sex/group (week 5) prior to sacrifice. No gross post-mortem examination was performed on these animals; however, selected tissues (blood, lungs, liver, kidneys and brain) were removed, weighed and shipped frozen to the sponsor for assay.

The remaining animals remained on test for a two- or four-week recovery period. After two and four complete weeks post-exposure, 10 animals/sex/group were sacrificed (week 7 and week 9). Five animals/sex/group were evaluated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations, while the remaining 5 animals/sex/group were processed for chemical assays by the sponsor.

Animals were exposed to cumulative mean analytical concentrations of 1.33, 7.17 and 9.54 mg/m³ of organic tin and target concentrations of 1, 10 and 30 mg/m³, respectively. Daily weighted mean nominal concentrations were 4.6, 25.1 and 484 mg/m³ tin, respectively. Particle size distribution measurements indicated the test atmosphere contained particles having a mass median aerodynamic diameter in the range 0.98 to 1.5 microns. The particle size distribution measurement revealed a significant level of aerosol in all chambers containing test material. The level of particulate in the Group I chamber was comparable to the level or particulate found in room air. This result indicated the test material was respirable to the rat.

Three high dose goup males and one high dose group female died during the exposure phase of the study. These deaths all occurred after 13 to 15 days of exposure and were considered related to exposure to the test material.

A number of findings were notable in the physical observation data of the treated animals. For the most part, these findings occurred at the high exposure level during the exposure phase of the study. These findings included mucoid nasal discharge, rales, lacrimation, salivation, rough coat, abdominal distension (males only), ano-genital staining and discolouration of the fur. In general these findings were not evident during the recovery phase of the study.

The mean body weights of the males and females in the high-exposure level were significantly reduced compared to their respective controls during part (females) or all (males) of the 4-week exposure phase of the study. The differences from control noted in the mean body weights of the high-exposure level animals progressively decreased during the recovery period.

The haematology data of the treated males and females exhibited slight, though in some cases, statistically significant differences from control. These included increased mean haemoglobin value and erythrocyte counts in the high-dose males at week 5 (end of the exposure phase) and, increased mean haemoglobin and haematocrit values and erythrocyte counts in the high-dose females at week 5 as well as increased erythrocyte counts in the low- and mid-dose female groups. Differences from control noted following 2 weeks and 4 weeks of recovery (weeks 7 and 9) included increased mean erythrocyte counts in the high-dose males (week 7) and, increased mean haemoglobin, haematocrit and erythrocyte counts in the mid- and high-dose males (week 9). The haematology data of the females following 2 and 4 weeks of recovery were considered unremarkable.

Necropsy was performed on animals marked for the terminal, first and second recovery sacrifices as well as unscheduled deaths. Grossly, the incidence of lung discolouration was increased in exposed males and females. Microscopically, amorphous material, (perhaps the test material or hydrolysis products) and alveolar oedema were evident in the lungs of exposed males and females. Other lung changes which occurred with increased incidence and severity in the exposed groups included peribronchial lymphoid cell accumulation and perivascular lymphoid cell infiltrate, extravagated erythrocytes (males only), and accumulation of alveolar macrophages. Dose related responses were shown only by alveolar oedema in both sexes and by alveolar erythrocytes in males only.

For the local effects (microscopic findings in lungs), the LOAEL was 3.00 mg test material/m³ (1.33 mg Sn/m³).

For the systemic effect, the NOAEL was 16.18 mg test material/m³ (7.17 mg Sn/m³). Mortality and several clinical signs were observed at 21.53 mg test material/m³.

The specific mode of action of the test material i.e. corrosiveness, does not support the need for any classification for repeated exposure systemic effects. Animals in the study were exposed whole body to very small particles of the test material (mass mean aerodynamic diameter in the range 0.98 to 1.5 microns) and actually signs of the same irritating action exerted on all the sites-of-contact (i.e. lungs, skin and stomach) were noted. These included clinical signs such as mucoid nasal discharge, rales, lachrymation, salivation, rough coat and discolouration of the fur, all indicative of irritation, and macro- and microscopic findings. Alveolar oedema and extravagated erythrocytes (accompanied by peribronchial/perivascular lymphoid accumulation/ infiltration and accumulation of alveolar macrophages) were observed in the lungs; mucous/purulent exudates were found in the nose turbinate sections; acanthosis and hyperkeratosis were noted microscopically in the skin but also purulent dermatitis involving the more exposed areas of the body (i.e. the external ear, extremities and skin) were observed, especially in animals which died. In the stomach, infarction (haemorrhage in one case) was also present, especially affecting animals which died. These findings are all most feasibly of local, site-of-contact origin, and are addressed by classification for site-of-contact effects.

There is no evidence of other organ toxicity. The haematological changes in the number of erythrocytes and mean haemoglobin concentration were slight, although attaining statistical significance, and were considered secondary to the lesions, often haemorrhagic, occurring in affected organs and tissues. Clinical chemistry did not evidence any change indicative of specific organ toxicity, either on liver function, as was instead noted in the 90-day dietary oral study.

Based on the lack of indications of any specific target organ systemic toxicity and on the specific mode of action of the test material, no classification for repeated exposure on the basis of this study is proposed for the test material.

Endpoint:
short-term repeated dose toxicity: inhalation
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:
NOAEC
Effect level:
< 3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
Key result
Dose descriptor:
LOAEC
Effect level:
3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
other: local effects (microscopic findings in lung). 3 mg/m³ (test material) = 1.33 mg Sn/m³
Key result
Dose descriptor:
NOAEC
Effect level:
16.18 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
other: Systemic effects. Mortality and several clinical signs were observed at 21.53 mg/m³ (test material). 16.18 mg/m³ (test material) = 7.17 mg Sn/m³
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEC
16.18 mg/m³
Study duration:
subacute
Species:
rat

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Referenceopen allclose all

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
03 September 1985 to 01 October 1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Reason / purpose for cross-reference:
other: read-across target
Qualifier:
no guideline followed
Principles of method if other than guideline:
This study was designed to assess the toxic effects of the test material when administered by inhalation as an vapour/aerosol to Sprague-Dawley derived rats (35/sex/group) for six hours per day, five days per week, for four weeks at target concentrations of 1, 10 and 30 mg/m³
GLP compliance:
yes (incl. QA statement)
Remarks:
Statement of compliance with US EPA's GLP Standards and applicable Standard Operating Procedures with some exceptions noted.
Limit test:
no
Species:
rat
Strain:
other: CD (Sprague-Dawley derived)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Age at initiation of exposure: approx. 9 weeks old (males and females)
- Initial body weights: 278 - 337 g (males, mean = 308) and 160 - 204 g (females, mean = 182).
- Acclimation: Animals were acclimated for 4 weeks and were examined by the staff veterinarian. Animals considered unsuitable for the study were excluded prior to random selection for group assignment.
- Housing:
During non-exposure periods animals were doubly-housed in suspended stainless steel wire mesh cages during the first week of acclimation and then individually housed during the rest of the acclimation period and all non-exposure periods.
During exposure periods: Animals were doubly-housed in similar cages when the number of animals was even and any remaining odd animal was housed individually. Chamber temperature ranged between 21 - 30°C and chamber RH between 44 - 100%.
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature: 67 - 76°F
- Humidity: 30 - 70%
- Photoperiod: 12 hour light/dark cycle (7 am to 7 pm)
Route of administration:
inhalation
Type of inhalation exposure:
whole body
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
>= 0.98 - <= 1.7 µm
Remarks on MMAD:
MMAD / GSD: The MMAD were as follows:
Group I (control): N/A
Group II: 0.98 microns
Group III: 1.7 microns
Group IV: 1.5 microns
Details on inhalation exposure:
- The test material was administered as a vapour/aerosol to male and female CD (Sprague-Dawley derived) rats, via inhalation (administered in the breathing zone of the animals).   
- Target exposure levels: 0 (control), 1, 10, and 30 mg/m³. Exposure levels were selected on the basis of multiples of the current TLV at the time.
- The stainless steel and glass chambers in which the animals were exposed had a total volume of 1 m³ with an effective volume of 760 L. The airflow rates in groups I-IV were 205-209 L/min, air change was 4.8-4.9 min, and 99 % equilibrium time was 22.0-22.5 min.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
- Air samples from all exposure chambers were collected (via impinger) at least 4 times over the test period. Additionally, distribution samples (i.e., one at the top and one at the bottom of the chamber) were collected from the test material exposure chambers over the course of the exposure period.
- Samples were sent to the sponsor for analysis by atomic absorption spectroscopy (AAS). Particle size distribution measurements were made weekly over the exposure period.
- Mean measured (target) exposure concentrations were 1.33 (1.0), 7.17 (10), and 9.54 (30) mg Sn/m³ (ca. 2.4, 23.8 and 71.3 mg test material/m³ target conc). The median particle diameter in the exposure chambers ranged from 0.98-1.7 µm. The particulate level in the low concentration exposure chamber (1 mg/m³) was comparable to that found in room air, indicating the test material was respirable to the rat.
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
Daily, 6 hours/day, 5 days/week
Total 20 exposures/sex/group
Dose / conc.:
1 mg/m³ air
Remarks:
Target concentration
Dose / conc.:
10 mg/m³ air
Remarks:
Target concentration
Dose / conc.:
30 mg/m³ air
Remarks:
Target concentration
No. of animals per sex per dose:
35 per sex per dose
Control animals:
yes, concurrent no treatment
Details on study design:
- Post-exposure recovery period: 0 weeks (15 animals/sex/dose), 2 weeks (10 animals/sex/dose), or 4 weeks (10 animals/sex/dose).
- The test material concentrations were calculated from the target tin (Sn) concentrations using the conversion factor [282.17/118.69] consisting of the molecular weights of the test material and Sn, respectively. All measured Sn was attributed to the test material.
Positive control:
None
Observations and examinations performed and frequency:
In-life observations:
- For mortality and gross signs of toxic effects - twice daily, once in the morning and once in the afternoon.
- Animals underwent physical examination pre-test and weekly thereafter.  
- Ophthalmoscopic examinations were performed pre-test and on weeks 5, 7, and 8.
- Body weights were recorded prior to testing, weekly during exposure, and prior to sacrifice (after fasting).  
Sacrifice and pathology:
- After 4 weeks exposure, 10 animals/sex/group were sacrificed and subjected to clinical study, postmortem examination, organ weight determination, and histopathological evaluation. An overnight urine sample was collected from an additional 5 animals/sex/group. These animals were then sacrificed and selected tissues (blood, lungs, liver, kidneys and brain) were removed and sent to the sponsor for assay. No postmortem examinations of these animals were conducted at the test laboratory.
- The remaining animals were retained for a 2- or 4-week recovery period. After the 2- and 4-week recovery periods, 10 animals/sex/group were sacrificed. Five animals/sex/group underwent clinical study, postmortem  examination, organ weight determination, and histopathological evaluation (when visibly abnormal organs were noted) at the test laboratory. The remaining 5 animals/sex/group were processed as described previously and sent to the sponsor for assay.
- Sacrifice method: Exsanguination under ether anaesthesia.
Other examinations:
- Blood samples were obtained from fasted animals, and separated into two aliquots for haematology and clinical chemistry.
- Urinalysis was also performed.
Statistics:
Body weights, haematology and clinical chemistry parameters, organ weights and organ/body weight ratios were analysed. Mean values of all treated groups were compared to control at each time interval.
Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Physical observations, including mucoid nasal discharge, rales, lacrimation, salivation, rough coat, abdominal distension (males), ano-genital staining, and fur discolouration, were observed primarily in the high-exposure group (30 mg/m³). These symptoms reduced during the recovery period.
Mortality:
mortality observed, treatment-related
Description (incidence):
- Three male rats and one female rat in the high exposure group (30 mg/m³) died during exposure. The deaths occurred after 13-15 days of exposure and were considered test material-related.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Mean body weights of male and female rats in the high-exposure group (30 mg/m³) were significantly lower than controls during all (male) or part (females) of the 4-week exposure period. The differences in animal weights (i.e., treated vs. control) decreased during the recovery period.
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:
no effects observed
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
- Post-exposure (pre-recovery) haematology data indicated slight to sometimes-significant differences from the control group. In the high-exposure group (30 mg/m³) these included increased mean haemoglobin values (males and females), increased mean erythrocyte counts (males and females), and increased mean haematocrit values (females). Female rats in all exposure groups exhibited increased mean erythrocyte counts. Differences from controls were slight, though sometimes significant.
- Haematology results in female rats in the recovery groups were comparable to controls. Male rats in the recovery groups exhibited increased mean erythrocyte counts (high dose group - 2 weeks recovery) and increased haematocrit, haemoglobin, and erythrocyte counts (mid and high dose group - 4 weeks recovery).
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Necropsy results reported primarily involved lung tissue. Observations related to exposed males and females included increased discolouration, amorphous material in lungs (potential test material or hydrolysis product), alveolar oedema (dose-related), peribronchial lymphoid cell accumulation, perivascular lymphoid cell infiltrate, extravasated alveolar erythrocytes (males only, dose-related), and accumulation of alveolar macrophages and neutrophilic infiltrates.
- The lesions and their severity scores represent the expected response of pulmonary tissue to introduction of a foreign and known corrosive material. Low-, mid- and high-dose males and females had increased lesion mean severity scores for amorphous material in their lungs compared to controls. The no-effect-level would be expected to be < 1 mg Sn/m³ (< 2.4 mg test material/m³).
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Other effects:
effects observed, treatment-related
Description (incidence and severity):
Skin sections from high-dose males and females showed epidermal acanthosis and hyperkeratosis.
Key result
Dose descriptor:
NOAEC
Effect level:
< 3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
Key result
Dose descriptor:
LOAEC
Effect level:
3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
other: local effects (microscopic findings in lung). 3 mg/m³ (test material) = 1.33 mg Sn/m³
Key result
Dose descriptor:
NOAEC
Effect level:
16.18 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
other: Systemic effects. Mortality and several clinical signs were observed at 21.53 mg/m³ (test material). 16.18 mg/m³ (test material) = 7.17 mg Sn/m³
Critical effects observed:
not specified

Table 1 : Mean Body Weight Values

Sex

Dose (mg/m³)

Exposure period

Recovery period

W0

W1

W2

W3

W4

W5

W6

W7

W8

M

0

308

+/-13

342

+/-18

367

+/-20

388

+/-21

405

+/-27

422

+/-30

438

+/-34

463

+/-32

480

+/-35

M

1

308

+/-13

344

+/-18

353*

+/-20

378

+/-23

398

+/-26

417

+/-30

437

+/-37

441

+/-38

455

+/-36

M

10

308

+/-14

339

+/-17

356

+/-20

376

+/-23

398

+/-27

419

+/-29

444

+/-30

470

+/-41

483

+/-43

M

30

307

+/-13

331*

+/-15

346**

+/-17

354**

+/-19

376**

+/-23

394*

+/-25

425

+/-29

451

+/-41

467

+/-41

F

0

182

+/-11

240

+/-12

222

+/-14

237

+/-14

248

+/-15

261

+/-19

261

+/-19

271

+/-21

277

+/-23

F

1

182

+/-10

204

+/-11

218

+/-12

236

+/-13

248

+/-14

254

+/-16

263

+/-17

266

+/-16

276

+/-18

F

10

183

+/-11

229**

+/-15

218

+/-15

233

+/-16

246

+/-17

248

+/-18

256

+/-19

262

+/-21

268

+/-20

F

30

182

+/-10

198

+/-13

214

+/-14

227*

+/-15

235**

+/-17

243*

+/-18

254

+/-21

259

+/-22

266

+/-19

*, ** results statistically significant (*p < 0.05, **p < 0.01)

Table 2 : Mean Haematology Values – Week 5

Sex

Dose (mg/m³)

HGB (g/dl)

HCT (%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

17.3

+/-0.5

40

+/-1

7.65

+/-0.21

9.76

+/-1.59

1.9

+/-0.4

13.8

+/-3.4

M

1

17.5

+/-0.9

40

+/-2

7.66

+/-0.41

9.78

+/-0.84

1.7

+/-0.4

13.5

+/-4.2

M

10

18.2

+/-1.6

40

+/-1

7.75

+/-0.36

9.81

+/-1.18

2.4

+/-0.6

13.3

+/-2.7

M

30

18.0

+/-0.7

40

+/-2

7.91

+/-0.44

9.55

+/-1.25

1.9

+/-0.7

13.8

+/-3.4

F

0

16.2

+/-0.5

37

+/-1

6.79

+/-0.20

10.72

+/-2.08

2.4

+/-0.5

9.0

+/-1.9

F

1

16.7

+/-0.5

39*

+/-1

7.13*

+/-0.19

10.21

+/-1.64

2.2

+/-0.6

10.4

+/-2.4

F

10

16.8

+/-0.6

39

+/-2

7.06*

+/-0.33

9.69

+/-1.76

1.9

+/-0.4

11.4

+/-2.5

F

30

17.4**

+/-0.5

40**

+/-1

7.33**

+/-0.21

9.92

+/-0.76

2.6

+/-0.8

11.5

+/-3.5

*, ** results statistically significant (*p < 0.05, **p < 0.01)

HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Table 3 : Mean Haematology Values – Week 7

Sex

Dose (mg/m³)

HGB

(g/dl)

HCT

(%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

16.3

+/-0.3

46

+/-1

7.25

+/-0.23

11.39

+/-1.21

1.1

+/-0.3

13.6

+/-3.6

M

1

16.7

+/-0.5

48

+/-1

7.65

+/-0.27

9.76

+/-1.28

1.2

+/-0.4

15.6

+/-3.6

M

10

16.9

+/-0.6

48

+/-3

7.61

+/-0.22

11.11

+/-1.29

1.0

+/-0.4

13.4

+/-2.8

M

30

16.8

+/-0.5

47

+/-2

7.73*

+/-0.28

10.05

+/-1.34

0.9

+/-0.3

14.0

+/-4.4

F

0

16.4

+/-0.2

46

+/-2

6.85

+/-0.29

10.57

+/-0.62

0.9

+/-0.3

8.7

+/-1.1

F

1

16.5

+/-0.5

48

+/-2

7.11

+/-0.21

9.82

+/-1.28

0.8

+/-0.3

10.8

+/-3.1

F

10

16.6

+/-0.3

48

+/-1

7.18

+/-0.26

10.34

+/-1.34

0.7

+/-0.2

9.1

+/-1.3

F

30

16.9

+/-0.2

49

+/-1

7.24

+/-0.19

11.62

+/-2.58

0.8

+/-0.4

9.9

+/-1.2

*, ** results statistically significant (*p < 0.05, **p < 0.01)

HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Table 4 : Mean Haematology Values – Week 9

Sex

Dose (mg/m³)

HGB

(g/dl)

HCT

(%)

RBC (mil/ul)

PLAT (100 T/ul)

RETIC (% RBC)

WBC (thous/ul)

M

0

15.9

+/-0.3

46

+/-1

7.43

+/-0.34

9.59

+/-1.77

0.7

+/-0.3

12.8

+/-1.9

M

1

16.1

+/-0.4

47

+/-1

7.58

+/-0.25

9.75

+/-1.38

0.7

+/-0.2

15.3

+/-2.3

M

10

16.9*

+/-0.7

48

+/-3

7.75

+/-0.39

10.97

+/-2.00

0.8

+/-0.4

13.7

+/-1.0

M

30

17.2**

+/-0.7

49*

+/-1

7.60

+/-0.43

9.43

+/-1.19

0.5

+/-0.2

13.3

+/-3.5

F

0

16.5

+/-0.2

48

+/-1

7.19

+/-0.19

9.65

+/-1.43

0.7

+/-0.2

9.7

+/-3.0

F

1

16.5

+/-1.3

48

+/-4

7.32

+/-0.68

9.16

+/-0.86

0.5

+/-0.2

8.9

+/-1.4

F

10

16.0

+/-1.5

46

+/-5

6.96

+/-0.60

9.09

+/-1.22

0.6

+/-0.2

8.6

+/-1.3

F

30

16.4

+/-1.6

48

+/-5

7.22

+/-0.48

9.37

+/-0.95

0.7

+/-0.2

9.9

+/-2.9

*, ** results statistically significant (*p < 0.05, **p < 0.01)

+/- HGB = haemoglobin; HCT = haematocrit; RBC = red blood cells ; PLAT = Platelet count; RETIC = reticulocyte count; WBC = white blood cells

Conclusions:
Under the conditions of the study the LOEC for local effects (microscopic findings in lungs) was 3.00 mg test material/m³ (1.33 mg Sn/m³).
For the systemic effect, the NOAEL was 16.18 mg test material/m³ (7.17 mg Sn/m³). Mortality and several clinical signs were observed at 21.53 mg/m³. As the mode of action of the test material's apparent toxicity seen in the repeat dose inhalation study is not deemed to be as a result of systemic toxic effects as a result of inhalation, but rather the test materials particular mode of action (corrosive effects) it is proposed that the test material is not classified for repeated toxicity.
Executive summary:

This study was designed to assess the toxic effects of the test material when administered by inhalation as a vapour/aerosol to Sprague-Dawley derived rats for six hours per day, five days per week, for four weeks at target concentrations of 1, 10 and 30 mg/m³. Control animals received house-supply air only while in chamber.

After four weeks of exposure (week 5), up to 15 animals/sex/group were sacrificed. The first 10 animals/sex/group were pre-designated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations (Groups I and IV animals only). An overnight urine sample was collected on the remaining 5 animals/sex/group (week 5) prior to sacrifice. No gross post-mortem examination was performed on these animals; however, selected tissues (blood, lungs, liver, kidneys and brain) were removed, weighed and shipped frozen to the sponsor for assay.

The remaining animals remained on test for a two- or four-week recovery period. After two and four complete weeks post-exposure, 10 animals/sex/group were sacrificed (week 7 and week 9). Five animals/sex/group were evaluated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations, while the remaining 5 animals/sex/group were processed for chemical assays by the sponsor.

Animals were exposed to cumulative mean analytical concentrations of 1.33, 7.17 and 9.54 mg/m³ of organic tin and target concentrations of 1, 10 and 30 mg/m³, respectively. Daily weighted mean nominal concentrations were 4.6, 25.1 and 484 mg/m³ tin, respectively. Particle size distribution measurements indicated the test atmosphere contained particles having a mass median aerodynamic diameter in the range 0.98 to 1.5 microns. The particle size distribution measurement revealed a significant level of aerosol in all chambers containing test material. The level of particulate in the Group I chamber was comparable to the level or particulate found in room air. This result indicated the test material was respirable to the rat.

Three high dose goup males and one high dose group female died during the exposure phase of the study. These deaths all occurred after 13 to 15 days of exposure and were considered related to exposure to the test material.

A number of findings were notable in the physical observation data of the treated animals. For the most part, these findings occurred at the high exposure level during the exposure phase of the study. These findings included mucoid nasal discharge, rales, lacrimation, salivation, rough coat, abdominal distension (males only), ano-genital staining and discolouration of the fur. In general these findings were not evident during the recovery phase of the study.

The mean body weights of the males and females in the high-exposure level were significantly reduced compared to their respective controls during part (females) or all (males) of the 4-week exposure phase of the study. The differences from control noted in the mean body weights of the high-exposure level animals progressively decreased during the recovery period.

The haematology data of the treated males and females exhibited slight, though in some cases, statistically significant differences from control. These included increased mean haemoglobin value and erythrocyte counts in the high-dose males at week 5 (end of the exposure phase) and, increased mean haemoglobin and haematocrit values and erythrocyte counts in the high-dose females at week 5 as well as increased erythrocyte counts in the low- and mid-dose female groups. Differences from control noted following 2 weeks and 4 weeks of recovery (weeks 7 and 9) included increased mean erythrocyte counts in the high-dose males (week 7) and, increased mean haemoglobin, haematocrit and erythrocyte counts in the mid- and high-dose males (week 9). The haematology data of the females following 2 and 4 weeks of recovery were considered unremarkable.

Necropsy was performed on animals marked for the terminal, first and second recovery sacrifices as well as unscheduled deaths. Grossly, the incidence of lung discolouration was increased in exposed males and females. Microscopically, amorphous material, (perhaps the test material or hydrolysis products) and alveolar oedema were evident in the lungs of exposed males and females. Other lung changes which occurred with increased incidence and severity in the exposed groups included peribronchial lymphoid cell accumulation and perivascular lymphoid cell infiltrate, extravagated erythrocytes (males only), and accumulation of alveolar macrophages. Dose related responses were shown only by alveolar oedema in both sexes and by alveolar erythrocytes in males only.

For the local effects (microscopic findings in lungs), the LOAEL was 3.00 mg test material/m³ (1.33 mg Sn/m³).

For the systemic effect, the NOAEL was 16.18 mg test material/m³ (7.17 mg Sn/m³). Mortality and several clinical signs were observed at 21.53 mg test material/m³.

The specific mode of action of the test material i.e. corrosiveness, does not support the need for any classification for repeated exposure systemic effects. Animals in the study were exposed whole body to very small particles of the test material (mass mean aerodynamic diameter in the range 0.98 to 1.5 microns) and actually signs of the same irritating action exerted on all the sites-of-contact (i.e. lungs, skin and stomach) were noted. These included clinical signs such as mucoid nasal discharge, rales, lachrymation, salivation, rough coat and discolouration of the fur, all indicative of irritation, and macro- and microscopic findings. Alveolar oedema and extravagated erythrocytes (accompanied by peribronchial/perivascular lymphoid accumulation/ infiltration and accumulation of alveolar macrophages) were observed in the lungs; mucous/purulent exudates were found in the nose turbinate sections; acanthosis and hyperkeratosis were noted microscopically in the skin but also purulent dermatitis involving the more exposed areas of the body (i.e. the external ear, extremities and skin) were observed, especially in animals which died. In the stomach, infarction (haemorrhage in one case) was also present, especially affecting animals which died. These findings are all most feasibly of local, site-of-contact origin, and are addressed by classification for site-of-contact effects.

There is no evidence of other organ toxicity. The haematological changes in the number of erythrocytes and mean haemoglobin concentration were slight, although attaining statistical significance, and were considered secondary to the lesions, often haemorrhagic, occurring in affected organs and tissues. Clinical chemistry did not evidence any change indicative of specific organ toxicity, either on liver function, as was instead noted in the 90-day dietary oral study.

Based on the lack of indications of any specific target organ systemic toxicity and on the specific mode of action of the test material, no classification for repeated exposure on the basis of this study is proposed for the test material.

Endpoint:
short-term repeated dose toxicity: inhalation
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:
NOAEC
Effect level:
< 3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
Key result
Dose descriptor:
LOAEC
Effect level:
3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
gross pathology
other: local effects (microscopic findings in lung). 3 mg/m³ (test material) = 1.33 mg Sn/m³
Key result
Dose descriptor:
NOAEC
Effect level:
16.18 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
other: Systemic effects. Mortality and several clinical signs were observed at 21.53 mg/m³ (test material). 16.18 mg/m³ (test material) = 7.17 mg Sn/m³
Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LOAEC
3 mg/m³
Study duration:
subacute
Species:
rat

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3).

Oral repeated toxicity :

The toxicity of the test material was examined in Wistar rats using continuous administration in the diet for 13 consecutive weeks. In satellite groups of female rats, a reproduction/developmental screening study was also performed. The repeated dose toxicity study was conducted in accordance with the standardised guideline OECD 408, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

During the study, four groups of 10 rats per sex per group received diets containing 300, 1500, and 7500 mg/kg (ppm) of the test material in the feed. The control group was kept on an untreated diet.

These dose levels were based on the results of a preceding dose-range finding study that used doses of 0, 100, 300, 1000, and 5000 mg/kg diet. Clinical observations, growth, food consumption, food conversion efficiency, neurobehavioral testing, ophthalmoscopy, haematology, clinical chemistry, renal concentration test, urinalysis, organ weights and gross examination at necropsy, histopathology examination were used for detection of toxicity.

The calculated intake values for the three test groups receiving 300, 1500, and 7500 mg/kg diet were 19, 96, and 521 mg/kg bw/day for males and 20, 101, and 533 mg/kg bw/day in females. A treatment-related increase in urinary pH was seen in males of 1500 and 7500 mg/kg groups, but this change was not considered toxicologically relevant. The males of the 7500 mg/kg group showed significant increases in reticulocytes, total white blood cells, lymphocytes, ALP, ASAT, GGT, bile acids, triglycerides, potassium, and absolute and relative liver weights, and decreased prothrombin time. In females of the 7500 mg/kg group, triglycerides and relative liver weights were significantly increased and prothrombin time was decreased. These changes were considered treatment-related and toxicologically relevant. No other treatment-related changes that were significant were observed in the high dose group, or the lower groups.

Although not accompanied by histopathological findings, the changes in haematology, clinical chemistry, and liver weights are indicative of liver damage. On the basis of increases in ASAT, GGT, bile acids, triglycerides, and relative liver weights in animals of the 7500 mg/kg diet group, the NOAEL in this subchronic toxicity study was placed at 1500 mg/kg diet. This level is equivalent to 96 mg/kg bw/day in males and 101 mg/kg bw/day in females.

Inhalation repeated toxicity:

The toxic effects of the test material were assessed when administered by inhalation as a vapour/aerosol to Sprague-Dawley derived rats for six hours per day, five days per week, for four weeks at target concentrations of 1, 10 and 30 mg/m³. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

After four weeks of exposure (week 5), up to 15 animals/sex/group were sacrificed. The first 10 animals/sex/group were pre-designated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations (Groups I and IV animals only). An overnight urine sample was collected on the remaining 5 animals/sex/group (week 5) prior to sacrifice. No gross post-mortem examination was performed on these animals; however, selected tissues (blood, lungs, liver, kidneys and brain) were removed, weighed and shipped frozen to the sponsor for assay.

The remaining animals remained on test for a two- or four-week recovery period. After two and four complete weeks post-exposure, 10 animals/sex/group were sacrificed (week 7 and week 9). Five animals/sex/group were evaluated for clinical laboratory studies, gross post-mortem examinations, organ weight measurements and histopathological evaluations, while the remaining 5 animals/sex/group were processed for chemical assays by the sponsor.

Animals were exposed to cumulative mean analytical concentrations of 1.33, 7.17 and 9.54 mg/m³ of organic tin and target concentrations of 1, 10 and 30 mg/m³, respectively. Daily weighted mean nominal concentrations were 4.6, 25.1 and 484 mg/m³ tin, respectively. Particle size distribution measurements indicated the test atmosphere contained particles having a mass median aerodynamic diameter in the range 0.98 to 1.5 microns. The particle size distribution measurement revealed a significant level of aerosol in all chambers containing test material. The level of particulate in the Group I chamber was comparable to the level or particulate found in room air. This result indicated the test material was respirable to the rat.

Three high dose goup males and one high dose group female died during the exposure phase of the study. These deaths all occurred after 13 to 15 days of exposure and were considered related to exposure to the test material.

A number of findings were notable in the physical observation data of the treated animals. For the most part, these findings occurred at the high exposure level during the exposure phase of the study. These findings included mucoid nasal discharge, rales, lacrimation, salivation, rough coat, abdominal distension (males only), ano-genital staining and discolouration of the fur. In general these findings were not evident during the recovery phase of the study.

The mean body weights of the males and females in the high-exposure level were significantly reduced compared to their respective controls during part (females) or all (males) of the 4-week exposure phase of the study. The differences from control noted in the mean body weights of the high-exposure level animals progressively decreased during the recovery period.

The haematology data of the treated males and females exhibited slight, though in some cases, statistically significant differences from control. These included increased mean haemoglobin value and erythrocyte counts in the high-dose males at week 5 (end of the exposure phase) and, increased mean haemoglobin and haematocrit values and erythrocyte counts in the high-dose females at week 5 as well as increased erythrocyte counts in the low- and mid-dose female groups. Differences from control noted following 2 weeks and 4 weeks of recovery (weeks 7 and 9) included increased mean erythrocyte counts in the high-dose males (week 7) and, increased mean haemoglobin, haematocrit and erythrocyte counts in the mid- and high-dose males (week 9). The haematology data of the females following 2 and 4 weeks of recovery were considered unremarkable.

Necropsy was performed on animals marked for the terminal, first and second recovery sacrifices as well as unscheduled deaths. Grossly, the incidence of lung discolouration was increased in exposed males and females. Microscopically, amorphous material, (perhaps the test material or hydrolysis products) and alveolar oedema were evident in the lungs of exposed males and females. Other lung changes which occurred with increased incidence and severity in the exposed groups included peribronchial lymphoid cell accumulation and perivascular lymphoid cell infiltrate, extravagated erythrocytes (males only), and accumulation of alveolar macrophages. Dose related responses were shown only by alveolar oedema in both sexes and by alveolar erythrocytes in males only.

For the local effects (microscopic findings in lungs), the LOAEL was 3.00 mg test material/m³ (1.33 mg Sn/m³).

For the systemic effect, the NOAEL was 16.18 mg test material/m³ (7.17 mg Sn/m³). Mortality and several clinical signs were observed at 21.53 mg test material/m³.

The specific mode of action of the test material i.e. corrosiveness, does not support the need for any classification for repeated exposure systemic effects. Animals in the study were exposed whole body to very small particles of the test material (mass mean aerodynamic diameter in the range 0.98 to 1.5 microns) and actually signs of the same irritating action exerted on all the sites-of-contact (i.e. lungs, skin and stomach) were noted. These included clinical signs such as mucoid nasal discharge, rales, lachrymation, salivation, rough coat and discolouration of the fur, all indicative of irritation, and macro- and microscopic findings. Alveolar oedema and extravagated erythrocytes (accompanied by peribronchial/perivascular lymphoid accumulation/ infiltration and accumulation of alveolar macrophages) were observed in the lungs; mucous/purulent exudates were found in the nose turbinate sections; acanthosis and hyperkeratosis were noted microscopically in the skin but also purulent dermatitis involving the more exposed areas of the body (i.e. the external ear, extremities and skin) were observed, especially in animals which died. In the stomach, infarction (haemorrhage in one case) was also present, especially affecting animals which died. These findings are all most feasibly of local, site-of-contact origin, and are addressed by classification for site-of-contact effects.

There is no evidence of other organ toxicity. The haematological changes in the number of erythrocytes and mean haemoglobin concentration were slight, although attaining statistical significance, and were considered secondary to the lesions, often haemorrhagic, occurring in affected organs and tissues. Clinical chemistry did not evidence any change indicative of specific organ toxicity, either on liver function, as was instead noted in the 90-day dietary oral study.

Based on the lack of indications of any specific target organ systemic toxicity and on the specific mode of action of the test material, no classification for repeated exposure on the basis of this study is proposed for the test material.

Justification for classification or non-classification

No systemic toxic effects were seen in the repeated dose oral study at the appropriate dose levels that would trigger classification for toxicity via this route of exposure.

The effects seen in the inhalation repeated dose toxicity study were considered to be secondary to local effects of a corrosive ttest material. The major effects observed secondary to the corrosive local effects were substantiated by local effects at the portal of entry of the test material, changes in the lungs due to the expected response of pulmonary tissue following the introduction of a known corrosive material, small changes in haematalogy but no other target specific organs and no systemic adverse toxicity were reported.

Based on the lack of indications of any specific target organ systemic toxicity and on the specific mode of action of the test material, it is therefore proposed that the test material is not classified for repeated toxicity according to Regulation EC no.1272/2008.