Antimony pentachloride

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study is considered to be of limited reliability for the assessment of local lung effects predominantly because the incidence of interstitial chronic pneumonia and interstitial fibrosis in controls was higher than or equal to that of exposed animals.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Subchronic and Chronic Inhalation Toxicity of Antimony Trioxide in the Rat

Author:

Newton P.E., Bolte H.F., Daly I.W., Pillsbury B.D., Terrill J.B., Drew R.T., Ben-Dyke R., Sheldon A.W. and Rubins L.F.

Year:

1994

Bibliographic source:

Fund. Appl. Toxicol. 22, 561-576

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Guideline:

other: no guideline specified

Principles of method if other than guideline:

In a whole-body inhalation study, the sub-chronic toxicity of antimony trioxide was evaluated.

GLP compliance:

yes

Remarks:

self certified

Test material

Test material information

Constituent 1

Reference substance name:

Diantimony trioxide

EC Number:

215-175-0

EC Name:

Diantimony trioxide

Cas Number:

1309-64-4

Molecular formula:

Sb2O3

IUPAC Name:

dioxodistiboxane

Test material form:

not specified

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: male and female Fischer 344 rats from Charles River Breeding Laboratory (Kingston, NY)
- Age at study initiation: approx. 7 weeks old
- Weight at study initiation: 93 - 125 g (males and 83 - 100 g (females)
The animals were distributed in the exposure groups by a computerized random sort programm so that the mean group body weight were comparable.
- Housing: animals were doubly housed in elevated, stainless-steel, wire mesh cages during the first week of acclimation period and were individually housed thereafter
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 12 days
The animals were individually eartagged for identification.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 23°C
- Humidity (%): 40 - 60%
- Air changes (per hr): not stated
- Photoperiod (hrs dark / hrs light): 12/12-hours light/dark cycle


IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Remarks on MMAD:

MMAD / GSD: The mass medium aerodynamic diameter (MMAD) was 3.05 +- 0.21 micrometers with a geometric standard deviation (GSD) of 1.57 +- 0.06.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: four 6000 L chambers (Hartford, Aberdeen, MD)
- Method of holding animals in test chamber: each chamber held two 80-animal racks; each rack had 16 stainless-steel open mesh cages on each of five levels
Each test animal's location was rotated on a weekly basis throughout the chamber.
- Pressure in air chamber: chambers were operated at a slight negative pressure of -0.5 cm H2O relative to the surrounding area
- Air flow rate: chambers were operated dynamically at flow rates of 1880 - 2510 L/minute
- Air change rate: complete air change every 2.4 - 3.2 minutes
- Method of particle size determination: Particle size distribution measurements were made prestudy and during weeks 1-4, 8 and 13 using scanning electron microscopy and quantitative image analyses. During the studies the measurements were made using a TSI Aerodynamic Particle Sizer (Model 3300).
Chamber airflow, temperature and relative humidity were recorded hourly during the exposures.
The antimony trioxide exposure atmosphere was generated using fluidizing bed generators (Models 3400 and 9310; TSI, Inc., St. Paul, MN). In both
generators the powdered test material was metered from a reservoir into the fluidizing bed. The resultant dust-loaded stream were then delivered
from the top of the fluidizing bed to the respective inlet turrents of the chambers. Control animals were exposed to clean air only.
TEST ATMOSPHERE
- Brief description of analytical method used: Samples were analysed gravimetrically and analytically. Samples were collected on preweighted Whatman glass microfibre membrane filters held in close-faced filter holders.
The gravimetric concentration was calculated by dividing the filter weight gain by the sampling air volume.
The analytical concentration of antimony trioxide was determined by atomic absorption. Exposure concentrations were monitored by three 90-min
samples and one all-day sample.
- Samples taken from breathing zone: yes

Duration of treatment / exposure:

- 13 weeks followed by a 27-week observation period

Frequency of treatment:

- exposure for 6 hours/day, 5 days/week for

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0.000 mg/m³
Basis:
analytical conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
0.25 mg/m³
Basis:
analytical conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1.08 mg/m³
Basis:
analytical conc.

Doses / concentrations 4

Remarks:

Doses / Concentrations:
4.92 mg/m³
Basis:
analytical conc.

Doses / concentrations 5

Remarks:

Doses / Concentrations:
23.46 mg/m³
Basis:
analytical conc.

No. of animals per sex per dose:

25 males and 25 females per dose group, were exposed to an antimony trioxide concentration of 0, 0.25, 1.08, 4.92, or 23.46 mg/m³

Control animals:

yes

Details on study design:

values cited are target, not actual measured, concentrations

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Animals were observed twice daily for viability and overt signs of toxicity. Detailed observation were conducted weekly and body
weight were measured twice pretest, weekly hereafter, and at termination.
- Cage side observations checked in table were included.


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Hematological and clinical chemistry indices were evaluated in five animals per sex per group after 1, 2, 4, 8 and 13 weeks of
exposure. Blood samples were obtained. Hematological indices were determined on an ELT-8 Hematology Analyzer. Differential leukocyte counts and erythrocyte morphology were determined manually. Serum biochemical evaluations were determined using a CentrifiChem System 500. Sodium and
potassium determinations were performed using an Electrolyte 2 Analyzer.


BODY WEIGHT: Yes
- Time schedule for examinations: body weight were measured twice pretest, weekly hereafter, and at termination


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Ophthalmoscopic examinations were performed on all animals pretest and on the day before their scheduled
termination.
- Dose groups that were examined:


HAEMATOLOGY: Yes
- time schedule: after 1, 2, 4, 8 and 13 weeks of exposure
- Anaesthetic used for blood collection: Yes (identity) : light ethyl ether anesthesia
- Animals fasted: Yes
- How many animals: five animals per sex per group


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 1, 2, 4, 8 and 13 weeks of exposure
- Animals fasted: Yes
- How many animals: five animals per sex per group

Sacrifice and pathology:

GROSS PATHOLOGY: Yes: complete gross postmortem examinations were performed on all animals:
-the external surface
- all orifices
- the cranial cavity
- carcass
- the external and sectioned surface of the brain and spinal cord,
- nasal cavity and paranasal sinuses
-the thoracic, abdominal and pelvic cavities and their viscera
- the cervical tissues and organs

HISTOPATHOLOGY: Yes: sections of the following tissues from all animals were examined histologically:
- heart
- nasal turbinates
- larynx
- trachea
- lung
- peribronchial lymph node

Statistics:

Parametric data were analyzed using an analysis of variance. Statistically significant differences that were noted were further analyzed using either
Tukey's (equal population) or Scheffe's (unequal population) test of multiple comparisons. Nonparametric data were analyzed using Kruskal-Walis
analysis of variance and a test of multiple comparison. Survival was analyzed using the method of Thomas et. al (1977). The criterion for statistical
significance was set at 0.05.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

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:

effects observed, treatment-related

Haematological findings:

no effects observed

Clinical biochemistry findings:

not specified

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY
- no exposure-related mortalities were reported


BODY WEIGHT AND WEIGHT GAIN
- Male body weight gains were significantly lower in the highest dose group compared to the controls.
- The difference was small, approximately 6% and statistically significant from week 3 to the end of the study, except for week 12.
- Female body weight gains were unaffected by antimony trioxide exposure.


OPHTHALMOSCOPIC EXAMINATION
- Corneal irregularities were observed with about equal incidence, 30%, in all groups, including controls.
- The irregularities appeared after about 2 weeks of exposure and did not abate during the 27-week observation period.

HAEMATOLOGY
- No exposure-related changes in haematological parameters were noted.


ORGAN WEIGHTS
- In both sexes, the mean absolute and relative lung weights were significantly increased at the two highest dose levels by week 13 of exposure but
returned to normal after the 3rd week of the observation period.


GROSS PATHOLOGY
-no antimony trioxide related effects were found.


HISTOPATHOLOGY:
- Microscopic changes observed in the lungs.
- Chronic interstitial inflammation (minimal to moderate severity) and interstitial fibrosis (minimal to slight severity) was seen in the lungs of both
control and treated animals from the exposure and observation periods.
- During the observation period, these effects were most frequent in the highest dose group. Also, granulomatous inflammation (minimal to
moderate severity) in the lungs was most frequent in the highest dose group during the observation period.
- Bronchiolar/alveolar hyperplasia (minimal to mild severity) was seen in only two males from the highest dose group terminated following the
exposure period of the study. Alveolar macrophages were more numerous (minimal to moderate severity) in the lungs of the treated animals than in
their comparable controls.
- The exposed rats had scattered macrophages containing small particles of foreign material in the lungs and in the peribronchial lymph nodes
(minimal to moderate severity). The incidence and severities of these findings were greater during the observation period than during the exposure
period.
- No histopathologic findings were reported in any other tissues examined.

Effect levels

Basis for effect level:

other: see 'Remark'

Remarks on result:

not measured/tested

Remarks:

Effect level not specified (migrated information)

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Table 1: Microscopic findings after a 13-week inhalation exposure period to antimony trioxide.

.	Males					Females
Dose (mg/m^3)	0	0.25	1.08	4.92	23.46	0	0.25	1.08	4.92	23.46
Number of animals examined	25	25	25	25	25	25	25	25	25	25
Effect
Interstitium: chronic inflammation	17	15	11	13	16	15	11	13	11	15
Granulomatous inflammation	0	0	0	0	1	0	1	0	0	1
Interstitium: frosis	12	13	8	10	10	8	7	6	4	12
Bronchiolar/alveolar hyperplasia	0	0	0	0	2	0	0	0	0	0
Alveolar/intraalveolar macrophages	3	1	5	11	9	2	0	4	10	11
Alveolar/intraalveolar macrophages: foreign particulate material	0	8	11	17	23	0	4	11	20	23
Perronchial lymph node macrophages: foreign particulate material	0	1	0	1	3	0	0	0	3	3

Table 2: Microscopic findings related to the 13-week inhalation exposure period to antimony trioxide seen during the 27-week observation period.

.	Males					Females
Dose (mg/m^3)	0	0.25	1.08	4.92	23.46	0	0.25	1.08	4.92	23.46
Number of animals examined	25	25	25	25	25	25	25	25	25	25
Effect
Interstitium: chronic inflammation	15	13	17	17	25	9	14	12	16	25
Granulomatous inflammation	2	0	4	1	6	1	0	0	5	7
Interstitium: frosis	8	12	6	9	21	7	5	4	11	20
Bronchiolar/alveolar hyperplasia	0	0	0	0	0	0	0	0	0	0
Alveolar/intraalveolar macrophages	6	10	5	21	24	1	3	11	21	25
Alveolar/intraalveolar macrophages: foreign particulate material	0	17	22	25	25	0	13	23	25	25
Macrophages in the perivascular/perronchiolar aggregates of lymphoid cells: foreign particulate material	0	0	0	0	3	0	0	0	3	2
Perronchial lymph node macrophages: foreign particulate material	0	0	2	15	15	0	0	4	16	18

A reliable LOAEC or NOAEC can not be derived from this study, since this study can be regarded inconclusive for the local lung effects as the incidence of interstitial chronic pneumonia and interstitial fibrosis in controls is higher than or equal to exposed animals.

Applicant's summary and conclusion

Conclusions:

In conclusion, this study did not indicate any systemic toxic effects of diantimony trioxide after sub-chronic inhalation exposure in rats. For the local effects (chronic inflammation and fibrosis) in the lungs the study is regarded inconclusive since it is noted that the incidence of interstitial chronic inflammation and interstitial fibrosis in controls (17 and 12 out of 25 males and 15 and 8 out of 25 females, for the respective conditions) after 13 weeks is high and too severe in degree as to be completely satisfying. Thus, the study might reflect sub-chronic disease of moderate severity due to other causative agent than diantimony trioxide. However, the increase in alveolar macrophages may be regarded as a normal pulmonary response to the foreign particles entering the lung.