Dibismuth trisulphide

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-09-19 to 2012-09-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and Guideline compliant study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

adopted 22.07.2010

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

(30 May 2008 Amendment 06.07.2012)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

March 2003

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Dibismuth trisulphide

EC Number:

215-716-0

EC Name:

Dibismuth trisulphide

Cas Number:

1345-07-9

Molecular formula:

Bi2S3

IUPAC Name:

dibismuth trisulphide

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

Sex: female, nulliparous, non pregnant
Age of animals: young adult mice, 11-12 weeks (at start of the experiment)
Body weight range at starting: 17.9 -22.8 g
The weight variation in animals involved in the study did not exceed ± 20 % of the mean weight.
Acclimatization time: 7 days
Housing during acclimatization period: grouped caging in small groups
Housing during the test: grouped caging (5 animals/cage)
Cage type: type II. polypropylene/polycarbonate
Bedding: laboratory bedding
Light: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 22 ± 3 °C
Relative humidity: 30 – 70 %
Diet: ssniff® SM R/M-Z+H complete diet for rats and mice produced by ssniff Spezialdiäten GmbH, D-59494 Soest, Germany
Water: tap water from municipal supply, as for human consumption, from a bottle ad libitum

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, open

Vehicle:

DMSO

Challenge

Route:

other: not applicable because LLNA

Vehicle:

DMSO

Positive control substance(s):

yes

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

Based on the preliminary test results 100 % concentration of the test item (formulated in the selected vehicle of DMSO) was selected as the maximum concentration used in the main test in order to test the highest concentration possible. The test item was tested also at two additional, lower concentrations (50 % and 25 %) according to the relevant guidelines.

No. of animals per dose:

5

Details on study design:

Each mouse was topically treated with 25 μL of the appropriate formulations of the test item, of the positive control substance (positive control
group) or of the vehicles (negative control groups). The formulations were applied, with a pipette, on the dorsal surface of each ear. Each animal wasdosed once a day for three consecutive days (Days 1, 2 and 3). There was no treatment on Days 4, 5 and 6.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Use of the individual approach enabled the performance of a statistical analysis of the data. Statistical analysis was performed by SPSS/PC+ (4.0.1) software package. The heterogeneity of variance between groups was checked by Bartlett's test for the measured DPM values corrected with the mean background value. Since no significant heterogeneity was detected, a one-way analysis of variance was carried out. Since the result was positive Duncan's Multiple Range test was used to assess the significance of inter-group differences. Significance of the positive control response was evaluated by T-test versus control. Significance of the dose-response was evaluated by linear regression made with Microsoft Excel Software.

Results and discussion

Positive control results:

The positive control group animals were treated with 25 % HCA solution (dissolved in AOO) concurrent to the test item groups. No mortality, cutaneous reactions or signs of toxicity were observed in the positive control group.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

The mean DPM values per treatment group were as follows: negative control for the PC:AOO: 946.3 DPM positive control 25% HCA in AOO: 13518.3 DPM Test item: 100 % in DSMO: 2462.7 DPM 50 % in DMSO: 2394.9 DPM 25 % in DMSO: 3711.5 DPM Negative (vehicle) control for the test item DMSO: 1126.3

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

The mean DPM values per treatment group were as follows: negative control for the PC:AOO: 946.3 DPM positive control 25% HCA in AOO: 13518.3 DPM Test item: 100 % in DSMO: 2462.7 DPM 50 % in DMSO: 2394.9 DPM 25 % in DMSO: 3711.5 DPM Negative (vehicle) control for the test item DMSO: 1126.3

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Under the conditions of the present Local Lymph Node Assay, Dibismuth trisulfide tested at the maximum attainable concentration of 100 %
(i.e. 1 g/mL) and at concentrations of 50 % and 25% as suspension in a suitable vehicle (Dimethyl sulfoxide) was shown to have no sensitization
potential.

Executive summary:

The aim of this study was to determine the skin sensitization potential of Dibismuth trisulfide in the Local Lymph Node Assay (LLNA). Visually larger lymph nodes than the control was observed in the positive control group only. The observed SI values were 2.2, 2.1 and 3.3 at concentrations of 100 %, 50 % and 25 % test item, respectively. The observed proliferation values were statistically significant in all test item treated groups (Mann-Whitney U-test was performed using the individual DPM values corrected with the mean background value) compared to the relevant vehicle control (DMSO). No biologically relevant dose-related response was observed. Since the test was valid and no sign of systemic toxicity or irritation was observed, the proliferation values obtained are considered to reflect the real potential of the test item to cause lymphoproliferation in the Local Lymph Node Assay. Although the observed proliferation values were statistically significantly increased in all test item treated groups compared to the control and the SI value observed at concentration of 25 % was above the threshold value of 3, it was considered that these observations did not indicate sensitization potential of the test item Dibismuth trisulfide. This is also being supported by the fact that no effect was observed at 50% test concentration and therefore the effect observed at 25 % test concentration was considered to be coincidental. No dose-response effect was observed. It is also considered that the increased proliferation values and the borderline result at 25% might have been a consequence of a slight irritation effect rather than a sensitization effect. According to evaluation criteria of the relevant guidelines, although borderline result was observed for the test item and the increase of the lymphoproliferation proved to be statistically significant, the lack of a biologically relevant dose-related response is considered as evidence that Dibismuth trisulfide is not a sensitizer.