Dibismuth trisulphide

Endpoint summary

Description of key information

No 28-day or 90-day repeated dose toxicity study was available for dibismuth trisulfide. Since bismuth and dibismuth trisulfide represent both almost insoluble inorganic compounds and exhibit comparable properties the most reliable study from bismuth was used for read-across. In a 28 -day study in rats the NOEL for bismuth was determined to be 1000 mg/kg bw for males and females. Calculated for dibismuth trisulfide the NOEL was 1230 mg/kg bw  for males and females.
A non-GLP 14-day oral gavage dose range finding study on dibismuth trisulphide is available and supports the above derived value. In addition also an OECD 421 study with dibismuth trisulfide in pregnant animals supports the very low systemic toxicity of this compound.
In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test on repeated dose toxicity after inhalation and repeated dose toxicity after dermal exposure do not need to be conducted as a repeated dose toxicity study for oral application is available. In addition also a OECD 421 study with dibismuth trisulfide in pregnant animals showed the very low systemic toxics of this compound.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2005

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: No GLP, according to OECD

Qualifier:

according to guideline

Guideline:

other: Chemical Substances Control Law (1986)

Deviations:

not specified

GLP compliance:

not specified

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

Test animals:
-Crj: CD(SD) IGS rats (SPF) 36 female rats for the 28-d repeated oral dose toxicity study from Charles River Japan, Inc.
Age of animals: 5 weeks old
-Body weight range at starting of administration: 128-154g, 154-176g and 128-147g, repectively
- Diet: Pellet diet (MF, Oriental Yeast Co., Ltd.)
- Water: ad libitum, tap water irradiated by UV rays after passing through a 5µm filter
- Acclimatisation time: 7 days quarantine and acclimatization period

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2 °C
- Humidity (%): 55 % ± 15%
- Air changes (per hr): about 12 air exchanges/hour
- Lighting for 12 hours per day (7:00 to 19:00)

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

Prior to the 28-d oral toxicity study, a preliminary dose-finding study entitled "A Fourteen-Day Repeated Oral Toxicity Preliminary Study in Rats"
(dose Ievels: 0, I 00, 500, and 1,000 mg/kg; number of animals, 3 males and 3 females per group) and found no changes attributable to the test
substance in clinical signs, body weights, hematology, organ weights (brain, thymus, liver, kidney, adrenal glands, spieen, testis, and ovary),
on necropsy. On account of these findings, the highest dose Ievel was set at 1,000 rrig/kg, and the medium and lower dose Ievels were set at 200 and 40 mg/kg, respectively.
Thereafter, oral administration (gavage) was performed once a day in the morning throughout the 28-d dosing period according to the Chemical
Substances Control Law ( 1986), to 6 rats of each sex in the 200 and 40 mg/kg groups and to 12 rats of each sex in the control and 1,000
mg/kg groups. The dosing volume (10 ml/kg) for individual animals was calculated based upon the mostrecent body weight. Moreover, 6 rats in the control and 1,000 mg/kg groups were given to a 14-d recovery period after the completion of the dosing period.

Duration of treatment / exposure:

28 days

Frequency of treatment:

daily

Remarks:

Doses / Concentrations:
40, 200 and 1,000 mg/kg
Basis:
actual ingested

No. of animals per sex per dose:

6 rats of each sex in the 200 and 40 mg/kg groups and 12 rats of each sex 1,000 mg/kg groups

Control animals:

yes

Details on study design:

Testing Procedure
Prior to the 28-d oral toxicity study, we conducted a preliminary dose-finding study entitled "A Fourteen-Day Repeated Oral Toxicity Preliminary
Study in Rats" (dose Ievels: 0, I 00, 500, and 1,000 mg/kg; number of animals, 3 males and 3 females per group) and found no changes
attributable to the test substance in clinical signs, body weights, hematology, organ weights (brain, thymus, liver kidney, adrenal glands, spieen,
testis, and ovary), on necropsy. On account of these findings, the highest dose Ievel was set at 1,000 mg/kg, and the medium and lower dose Ievels were set at 200 and 40 mg/kg, respectively. Thereafter, oral administration (gavage) was performed once a day in the morning throughout the 28-d dosing period according to the Chemical Substances Control Law ( 1986), to 6 rats of each sex in the 200 and 40 mg/kg groups and to 12 rats of
each sex in the control and 1,000mg/kg groups. The dosing volume (10 ml/kg) for individual animals was calculated based upon the most recent
body weight. Moreover, 6 rats in the control and 1,000 mg/kg groups were given to a 14-d recovery period after the completion of the dosing
period.

Positive control:

not required

Observations and examinations performed and frequency:

For the 28-d repeated-dose toxicity study, the parameters described below were examined. Clinical signs, body weight, andfood consumption:
Clinical signs of the animals were observed four times on the dose day and thereafter once a day in the acute oral toxicity study, and twice a day
(before and after administration) throughout the dosing period, and once a day in the morning during the recovery period in the 28-d repeated-
dose toxicity study. The body weightof all animals and the gross weights of the feeders were measured before dosing and on days 4, 8, and 15 (the day of administrationwas designed as day 1) in the acute oral toxicity study, and once a week in the 28-d repeateddose toxicity study.
Hematology and blood chemistry:
On days of the scheduled necropsy, the animals were anesthetized by intraperitoneal injection of sodium thiopental
(Ravonal, Tanabe Seiyaku Co., Ltd.). Thereafter, blood samples were collected via the posterior vena cava. For hematology, we measured the
erythrocyte count (RBC), hemoglobin concentration (Hb), hematocrit value (Ht), mean corpuscular volume (MCV), mean corpuscular hemoglobin
(MCH), mean corpuscular hemoglobin concentration (MCHC), reticulocyte count, p1 atdet~.:uu nt (PLT), prulhrumbiu time (PT), aclivated partial
thromboplastin time (APTT), leukocyte count (WBC), and differential leukocyte count. For blood chemistry, we used the obtained serum samples to
measure the aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), y-glutamyltransferase (y G T), alkaline phosphatase (ALP),
total bilirubin, blood urea nitrogen (BUN), creatinine, glucose, total cholesterol, triglycerides, total protein, albumin, A/G ratio, calcium, inorganic
phosphorus, sodium (Na), potassium (K), and chlorine (Cl). Urinalysis: Fresh urine samples from s ix males and six females in each group were
collected on day 27, and the following test items were measured: pH, protein, glucose, ketone bodies, bilirubin, occult blood, urobilinogen.
No changes attributed to bismuth were found in the examinations during the dosing period. Therefore, examinations were not conducted during the recovery period.
Pathological and histopathological examination:
After the blood sampling, all animals were sacrificed by exsanguinat ion via the abdominal aorta and then subjected to necropsy. The fol lowing
organs of all animals were weighed: brain, liver, kidney, adrenal glands g land, thymus, spieen, testis, and ovary. Relativeorgan weights were
calculated from body weights on each necropsy day. Histopathological examination was performed on the heart, liver, spieen, kidneys, and
adrenals obtained from the animals of the control and I ,000 mg/kg groups, and on gross lesions of any group. The hematoxylin and eosin
staining specimens were prepared according to the standard procedure and then microscopically examined. No -changes attributed to bismuth
were found. Therefore, histopathological examination of argans and tissues except for gross lesions in the animals of the recovery group was not
conducted.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

There were no changes in clinical signs , body we ights, foodconsumption, hematology, urinalysis, organ weights, necropsy, or histopathological
findings in the 28-d repeated oral dose toxicity study. As a result of these findings, we determined the no-observed-effect Ievel (NOEL) of bismuth to be 1000 mg/kg for males and females and calculated on dibismuth trisulphide the no-observed-effect Ievel (NOEL) was 2460 mg/kg for males and females.

Dose descriptor:

NOEL

Effect level:

1 230 other: mg/kg bw/day

Based on:

other: calculated for dibismuth trisulfide

Sex:

male/female

Dose descriptor:

NOEL

Effect level:

1 000 other: mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Critical effects observed:

not specified

Conclusions:

The NOEL for bismuth was determined to be 1000 mg/kg bw for males and females. Since bismuth and dibismuth trisulfide are both almost insoluble inorganic compounds and exhibite comparable properties the results from bismuth were used used via read-across as supporting data. The calculated LD50 for dibismuth trisulfide is above 1230 mg/kg bw.

Executive summary:

There were no changes in clinical signs , body weights, food consumption, hematology, urinalysis, organ weights, necropsy, or histopathological findings in the 28-d repeated oral dose toxicity study with bismuth. As a result of these findings, the NOEL for bismuth was determined to be 1000 mg/kg for males and females. Since bismuth and dibismuth trisulfide are both almost insoluble inorganic compounds and exhibite comparable properties the results from bismuth were used used via read-across as supporting data. The calculated LD50 for dibismuth trisulfide is above 1230 mg/kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 230 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

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

Waiver

In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test on repeated dose toxicity after inhalation and repeated dose toxicity after dermal exposure do not need to be conducted as a repeated dose toxicity study for oral application is available.

 

Repeated dose toxicity study for oral application

Read-Across to Bismuth Repeated dose toxicity (28 day)

No repeated oral dose toxicity study is available for dibismuth trisulfide. Since bismuth and dibismuth trisulfide are both almost insoluble inorganic compounds and exhibit comparable properties the most reliable study from bismuth was used for read-across. In a 28 -day study in rats no changes in clinical signs, body weights, food consumption, hematology, urinalysis, organ weights, necropsy, or histopathological findings were seen. As a result of these findings, the NOEL for bismuth was determined to be 1000 mg/kg bw for males and females. Calculated for dibismuth trisulfide the NOEL was 1230 mg/kg bw for males and females.

 

14-day oral gavage dose finding study

A non-GLP 14-day oral gavage dose range finding study on dibismuth trisulphide is available and supports the above derived value. The test substance was administrated rats in the doses of 100, 300 and 1000 mg/kg bw. 5 animals per sex and dose were used. No clinical signs were observed at the highest dose tested.

OECD 421 Reproduction/Developmental Toxicity Screening Test

Furthermore, an OECD 421 Reproduction/Developmental Toxicity Screening Test with dibismuth trisulfide is available. The test substance was administrated for up to 43 or 49 days to the rats.

Observations included mortality, clinical signs, body weight, food consumption, mating, pregnancy and delivery process, as well as development of offsprings.

Under the conditions of this study dibismuth trisulfide did not cause toxic changes and did not influence the reproductive performance (gonad function, mating behavior, conception, pregnancy, parturition) in parental male and female Hsd.Brl.Han: Wistar rats or development of the F1 offspring from conception to day 4 post-partum after repeated dose oral administration at 1000, 300 or 100 mg/kg bw/day. Based on these

observations the No Observed Effect Levels (NOEL) were determined as follows:

NOEL for male rats: 1000 mg/kg bw/day

NOEL for female rats: 1000 mg/kg bw/day

NOEL for reproductive performance of the male rats: 1000 mg/kg bw/day

NOEL for reproductive performance of the female rats: 1000 mg/kg bw/day

NOEL for F1 Offspring: 1000 mg/kg bw/day

The result of the OECD 421 Reproduction/Developmental Toxicity Screening Test shows that the test substance is not toxic after repeated application at the limit dose concentration and supports the findings in a subacute study with dibismuth trisulfide and in a 14 day range study.

 

Conclusion

Summing up the repeated toxicity studies the endpoint for repeated dose toxicity is covered and no further testing is required especially as no effects at all were noted up to the limit dose in all tests at hand.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
No study with dibismuth trisulphide is available. Since bismuth and dibismuth trisulfide are both almost insoluble inorganic compounds and exhibit comparable properties the most reliable study from bismuth were used for read-across. This value is also supported by an OECD 421 study with dibismuth trisulfide (see reproduction toxicity).

Justification for selection of repeated dose toxicity inhalation - systemic effects endpoint:
In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test repeated dose toxicity after inhalation does not need to be conducted as a repeated dose toxicity study for oral application is available.

Justification for selection of repeated dose toxicity inhalation - local effects endpoint:
In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test repeated dose toxicity after inhalation does not need to be conducted as a repeated dose toxicity study for oral application is available.

Justification for selection of repeated dose toxicity dermal - systemic effects endpoint:
In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test repeated dose toxicity after dermal application does not need to be conducted as repeated dose toxicity studies for oral application are available.

Justification for selection of repeated dose toxicity dermal - local effects endpoint:
In accordance with column 2 of REACH Regulation EC (No) 1907/2006 Annex IX, section 8.6, the test repeated dose toxicity after dermal application does not need to be conducted as repeated dose toxicity studies for oral application are available. In addition, acute tests give us indication at all that the test substance might cause local effects at dermal contact.

Justification for classification or non-classification

According to the results of a repeated oral dose toxicity study, no classification and labelling is required according to Regulation No (EC) 1272/2008 (CLP) or Directive 67/548/EEC (DSD) criteria.