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Diss Factsheets

Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
2012-02-01 until 2012-02-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and Guideline compliant study
Justification for type of information:
Background: To induce sensitization, metal ions need to penetrate through the outer stratum corneum barrier layer of the skin and reach the underlying viable epidermis. Then, to become immunologically reactive, metal ions must bind to macromolecules such as proteins to form a hapten complex. Antigen presenting cells display this hapten complex on their cell surfaces and when the hapten is recognized as foreign by naïve T-lymphocyte cells, these cells undergo differentiation to form hapten-specific effector and memory helper T-cells (e.g., a person becomes sensitized). Upon repeated contact with the offending metal, at exposure levels that result in sufficient metal ion release and stratum corneum penetration, memory T-cells are recruited to the site of skin contact and elicit an inflammatory reaction (Stefaniak et al., 2014; Gibbs et al., 2018).
Regarding skin sensitization of cesium acetate as requested under REACH regulation 1907/2006, no data are currently available. To meet the skin sensitization endpoint requirement, read-across strategy with cesium salts was used (e.g. CsI, CsNO3 and CsOH).
Literature
Gibbs S, Kosten I, Veldhuizen R, Spiekstra S, Corsini E, Roggen E, Rustemeyer T, Feilzer AJ, Cees J. Kleverlaan CJ. 2018. Assessment of metal sensitizer potency with the reconstructed human epidermis IL-18 assay. Toxicology 393: 62–72.

Stefaniak AB, Duling MG,Geer L, and Virji MA. 2014. Dissolution of the metal sensitizers Ni, Be, Cr in artificial sweat to improve estimates of dermal bioaccessibility. Environ Sci Process Impacts 16: 341–351.
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 2017 (Protocole) to June 2017 (Final report)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 105 (Water Solubility)
Version / remarks:
adopted by the Council on 27 July 1995
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of method:
other: Two tests were performed concurrently using separate pyknometers
Key result
Water solubility:
> 1 000 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
100 mg/L
Remarks on result:
completely miscible
Conclusions:
Test substance was found to have a solubility of greater than 1000 g/L of water.
Executive summary:

The water solubility of the test item was determined according to OECD Guidelines for Testing of Chemicals (Method 105). The test substance was found to have a solubility of greater than 1000 g/L of water.

Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non GLP and non guideline study, but sufficient for hazard assessment together with read-across to other cesium nitrate.
Justification for type of information:
Background: To induce sensitization, metal ions need to penetrate through the outer stratum corneum barrier layer of the skin and reach the underlying viable epidermis. Then, to become immunologically reactive, metal ions must bind to macromolecules such as proteins to form a hapten complex. Antigen presenting cells display this hapten complex on their cell surfaces and when the hapten is recognized as foreign by naïve T-lymphocyte cells, these cells undergo differentiation to form hapten-specific effector and memory helper T-cells (e.g., a person becomes sensitized). Upon repeated contact with the offending metal, at exposure levels that result in sufficient metal ion release and stratum corneum penetration, memory T-cells are recruited to the site of skin contact and elicit an inflammatory reaction (Stefaniak et al., 2014; Gibbs et al., 2018).
Regarding skin sensitization of cesium acetate as requested under REACH regulation 1907/2006, no data are currently available. To meet the skin sensitization endpoint requirement, read-across strategy with cesium salts was used (e.g. CsI, CsNO3 and CsOH).
Literature
Gibbs S, Kosten I, Veldhuizen R, Spiekstra S, Corsini E, Roggen E, Rustemeyer T, Feilzer AJ, Cees J. Kleverlaan CJ. 2018. Assessment of metal sensitizer potency with the reconstructed human epidermis IL-18 assay. Toxicology 393: 62–72.

Stefaniak AB, Duling MG,Geer L, and Virji MA. 2014. Dissolution of the metal sensitizers Ni, Be, Cr in artificial sweat to improve estimates of dermal bioaccessibility. Environ Sci Process Impacts 16: 341–351.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
equivalent or similar to guideline
Guideline:
other: Landsteiner and Jacobs (1935) Studies on the sensitization of animals with simple chemical compounds. J. Exp. Med. 61, 643-657
Deviations:
not specified
Principles of method if other than guideline:
similar to that described by Landsteiner and Jacobs (1935) Studies on the sensitization of animals with simple chemical compounds. J. Exp. Med. 61, 643-657

A 0.1 ml vol of a 0.1% solution of the test compound was injected intracutaneously to separate skin sites of the animals three times weekly, for a total of nine treatments. Following a 2-wk period in which no further injections were made, a challenge dose of 0.1 ml of test compound was administered to both test and control animals in the same manner. Skin reactions were examined and recorded at 24,48, and 72 hr following the challenge dose.
GLP compliance:
no
Type of study:
other: SKIN SENSITIZATION BY INTRAPERITONEAL INJECTIONS
Justification for non-LLNA method:
The current endpoint has been fulfill with current available data. The current available data was made using a non-LLNA method. In addition and due to the available data rubisdium salts are not considered as a skin sensitizer. Therefore, no other test will be conducted for this endpoint.
Specific details on test material used for the study:
high purity material "99%"
Species:
guinea pig
Strain:
other: albino
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: young adult
- Weight at study initiation: 300 - 400 g
Route:
intradermal
Vehicle:
water
Concentration / amount:
0.1 mL vol of 0.1% solutionof the test compound
Day(s)/duration:
2 weeks
Route:
other: not specified
Concentration / amount:
0.1 ml of the test compound
Day(s)/duration:
after 2 weeks after first injection and then, skin examined at 24, 48 and 72 hours.
Adequacy of challenge:
not specified
No. of animals per dose:
control: 5 males
test group: 10 males
Details on study design:
RANGE FINDING TESTS: no data

MAIN STUDY
Fifteen young adult male albino guinea pigs weighing between 300 and 400 grams were used. Five animals served as a control group and 10 animals were assigned to the test group. The backs of the animals were clipped free of hair and the clipping repeated at various intervals during the study. The test materials, 0.1 ml (0.1 %), were injected intradermally to separate skin sites of the animals three times weekly for a total of nine treatments. The five control animals were treated in a manner identical to the test group but using the solvent, distilled water, as a control material. Twenty-four hours following each injection the reaction was measured for size. The animals in both the test and control groups were rested for a two-week period following the ninth injection. At the end of the two-week rest period a challenge dose of 0.1 ml was administered
to both the test and control animals in the same manner as before. Test sites were examined and reactions recorded at 24, 48 and 72 hours.
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.1 mLof test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
0.1 mL of the test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
72
Group:
test chemical
Dose level:
1 mL of the test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation

If the response to the challenge injection is greater in terms of intensity or local inflammatory response than to tbe sensitizing doses, or the numher of animals responding is substantially greater, then the material is considered to be a skin sensitizer.

There was no evidence of erythema, swelling or dicolorartion of the test sites after each of the nine sensitizing cutaneous injections or after the challenge dose. These results indicate that Cesium iodide did not induce cutaneous sensitisation in guinea pigs in any of the 10 test animals. On this basis the results of these guinea pig study indicate that cesium iodide is a non-sensitizer.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Cesium iodide did not induce cutaneous sensitisation in guinea pigs.
Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non GLP and non guideline study, but sufficient for hazard assessment together with read-across to other cesium nitrate.
Justification for type of information:
Background: To induce sensitization, metal ions need to penetrate through the outer stratum corneum barrier layer of the skin and reach the underlying viable epidermis. Then, to become immunologically reactive, metal ions must bind to macromolecules such as proteins to form a hapten complex. Antigen presenting cells display this hapten complex on their cell surfaces and when the hapten is recognized as foreign by naïve T-lymphocyte cells, these cells undergo differentiation to form hapten-specific effector and memory helper T-cells (e.g., a person becomes sensitized). Upon repeated contact with the offending metal, at exposure levels that result in sufficient metal ion release and stratum corneum penetration, memory T-cells are recruited to the site of skin contact and elicit an inflammatory reaction (Stefaniak et al., 2014; Gibbs et al., 2018).
Regarding skin sensitization of cesium acetate as requested under REACH regulation 1907/2006, no data are currently available. To meet the skin sensitization endpoint requirement, read-across strategy with cesium salts was used (e.g. CsI, CsNO3 and CsOH).
Literature
Gibbs S, Kosten I, Veldhuizen R, Spiekstra S, Corsini E, Roggen E, Rustemeyer T, Feilzer AJ, Cees J. Kleverlaan CJ. 2018. Assessment of metal sensitizer potency with the reconstructed human epidermis IL-18 assay. Toxicology 393: 62–72.

Stefaniak AB, Duling MG,Geer L, and Virji MA. 2014. Dissolution of the metal sensitizers Ni, Be, Cr in artificial sweat to improve estimates of dermal bioaccessibility. Environ Sci Process Impacts 16: 341–351.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Qualifier:
equivalent or similar to guideline
Guideline:
other: Landsteiner and Jacobs (1935) Studies on the sensitization of animals with simple chemical compounds. J. Exp. Med. 61, 643-657
Deviations:
not specified
Principles of method if other than guideline:
similar to that described by Landsteiner and Jacobs (1935) Studies on the sensitization of animals with simple chemical compounds. J. Exp. Med. 61, 643-657

A 0.1 ml vol of a 0.1% solution of the test compound was injected intracutaneously to separate skin sites of the animals three times weekly, for a total of nine treatments. Following a 2-wk period in which no further injections were made, a challenge dose of 0.1 ml of test compound was administered to both test and control animals in the same manner. Skin reactions were examined and recorded at 24,48, and 72 hr following the challenge dose.
GLP compliance:
no
Type of study:
other: SKIN SENSITIZATION BY INTRAPERITONEAL INJECTIONS
Justification for non-LLNA method:
The current endpoint has been fulfill with current available data. The current available data was made using a non-LLNA method. In addition and due to the available data rubisdium salts are not considered as a skin sensitizer. Therefore, no other test will be conducted for this endpoint.
Specific details on test material used for the study:
high purity material "99%"
Species:
guinea pig
Strain:
other: albino
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: young adult
- Weight at study initiation: 300 - 400 g
Route:
intradermal
Vehicle:
water
Concentration / amount:
0.1 mL vol of 0.1% solutionof the test compound
Day(s)/duration:
2 weeks
Route:
other: not specified
Concentration / amount:
0.1 ml of the test compound
Day(s)/duration:
after 2 weeks after first injection and then, skin examined at 24, 48 and 72 hours.
Adequacy of challenge:
not specified
No. of animals per dose:
control: 5 males
test group: 10 males
Details on study design:
RANGE FINDING TESTS: no data

MAIN STUDY
Fifteen young adult male albino guinea pigs weighing between 300 and 400 grams were used. Five animals served as a control group and 10 animals were assigned to the test group. The backs of the animals were clipped free of hair and the clipping repeated at various intervals during the study. The test materials, 0.1 ml (0.1 %), were injected intradermally to separate skin sites of the animals three times weekly for a total of nine treatments. The five control animals were treated in a manner identical to the test group but using the solvent, distilled water, as a control material. Twenty-four hours following each injection the reaction was measured for size. The animals in both the test and control groups were rested for a two-week period following the ninth injection. At the end of the two-week rest period a challenge dose of 0.1 ml was administered
to both the test and control animals in the same manner as before. Test sites were examined and reactions recorded at 24, 48 and 72 hours.
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
0.1 mLof test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test chemical
Dose level:
0.1 mL of the test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
72
Group:
test chemical
Dose level:
1 mL of the test compound
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation

If the response to the challenge injection is greater in terms of intensity or local inflammatory response than to tbe sensitizing doses, or the numher of animals responding is substantially greater, then the material is considered to be a skin sensitizer.

There was no evidence of erythema, swelling or dicolorartion of the test sites after each of the nine sensitizing cutaneous injections or after the challenge dose. These results indicate that Cesium hydroxide did not induce cutaneous sensitisation in guinea pigs in any of the 10 test animals. On this basis the results of these guinea pig study indicate that cesium hydroxide is a non-sensitizer.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Cesium hydroxide did not induce cutaneous sensitisation in guinea pigs.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
, adopted 2012
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
, adopted 2008
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Version / remarks:
, adopted 2003
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
Caesium nitrate
EC Number:
232-146-8
EC Name:
Caesium nitrate
Cas Number:
7789-18-6
Molecular formula:
Cs.HNO3
IUPAC Name:
cesium nitrate
Test material form:
solid: crystalline

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: TOXI-COOP ZRT. H-1103, Budapest, Cserkesz u. 90.
- Age at study initiation: young adult mice, 9-10 weeks (at start of the experiment)
- Weight at study initiation: 16.8 - 21.5 g
- Housing: grouped caging (5 animals/cage)in type II. polypropylene/polycarbonate cages
- Diet: Animals received ssniff® SM R/M-Z+H complete diet for rats and mice produced by ssniff Spezialdiäten GmbH, D-59494 Soest, Germany, ad libitum
- Water: tap water for human supply, ad libitum
- Acclimation period: 7 days (pre-test) and 21 days (main study)

ENVIRONMENTAL CONDITIONS
- Temperature: :22 ± 3 °C
- Humidity: 30 – 70 %
- Photoperiod: 12 hours daily, from 6.00 a.m. to 6.00 p.m.

Study design: in vivo (LLNA)

Vehicle:
other: 1 % Pluronic®PE 9200
Concentration:
25 %, 10 %, 5 % and 2.5 %
No. of animals per dose:
5 animals per dose
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: Solubility of the test item was evaluated in different solvents recommended by the relevant guideline. Appropriate solubility was achieved with aqueous 1 % Pluronic®PE 9200 (1 % Pluronic) with a maximum concentration of 25 % (w/v). The formulation was a real solution and applicability on the ears of animals was acceptable.

- Irritation: A preliminary irritation/toxicity screen was conducted in a similar experimental manner to the exposure phase of the main assay except there was no assessment of lymph node proliferation and fewer animals were used per dose group. Two groups of 2 CBA/Ca mice were treated with the test item formulations of 25 % or 10 % (w/v) in the vehicle (1 % Pluronic) once daily for 3 consecutive days.
No mortality was observed during the preliminary test.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay (Individual Approach)
- Criteria used to consider a positive response: The test item is considered as a skin sensitizer, if the following criteria are fulfilled:
That exposure to at least one concentration of the test item resulted in an incorporation of 3HTdR at least 3-fold or greater than recorded in control mice, as indicated by the stimulation index.


TREATMENT PREPARATION AND ADMINISTRATION:
Each mouse was topically treated with 25 µL of the appropriate formulations of the test item, of the positive control substance (positive control group) and of the vehicles (negative control groups). The formulations were applied, with a pipette, on the dorsal surface of each ear. Each animal was dosed once a day for three consecutive days (Days 1, 2 and 3). There was no treatment on Days 4, 5 and 6.
On Day 6 each mouse was intravenously injected via the tail vein with 250 µL of sterile PBS containing 20 µCi of
3H-methyl-thymidine using a hypodermic needle with 1 mL sterile syringe. Once injected, the mice were left for 5 hours
(± 30 minutes).
Five hours (± 30 minutes) after intravenous injection the mice were anesthetized by inhalation of Isofluran CP® and sacrificed. A single cell suspension was prepared and incorporated radioactivity was measured accordingly.

Clinical Observation:
During the main test (from Day 1 to Day 6) all animals were observed at least once a day for any clinical signs, including systemic toxicity and local irritation. Irritation was monitored by erythema scoring. Individual records were maintained.

Body Weight:
Individual body weights were recorded on Day 1 (beginning of the test) and on Day 6 (prior to 3HTdR injection) with a precision of ± 0.1 g.

Evaluation of the Results:
DPM was measured for each animal. The results were expressed as DPN (DPM divided by the number of lymph nodes). The mean DPM and DPN values were calculated for each treatment groups.
The stimulation index (SI = the mean DPN of a treated (positive control or test item) group divided by the DPN of the respective negative control group) for each treatment group was calculated. A stimulation index of 3 or greater is an indication of a positive result.

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 % (w/v) Hexyl cinnamic aldehyde (HCA) solution concurrent to the test item treated groups. No confounding effects of irritation or systemic toxicity were observed in the positive control group. Significant lymphoproliferative response (SI 3) was noted for HCA with stimulation index value of 11.82. The result of the positive control item demonstrated the appropriate performance of the test in accordance with the Guidelines and confirmed sensitivity and validity of the assay.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: The Stimulation index values per treatment group were as follows: negative control: 1.0 SI positive control: 11.82 SI Test item: 25 %: 0.91 SI 10 %: 0.72 SI 5 %: 0.97 SI 2.5 %: 1.05 SI
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: The mean DPM values per treatment group were as follows: negative control: 818.4.0 DPM positive control: 18398.6 DPM Test item: 25 %: 743.0 DPM 10 %: 588.0 DPM 5 %: 795.0 DPM 2.5 %: 858.6 DPM

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Cesium nitrate tested at 25 %, 10 %, 5% and 2.5 % as a solution in 1 % Pluronic was shown to have no sensitisation potential.
Executive summary:

The aim of this study was to determine the skin sensitisation potential of cesium nitrate in the Local Lymph Node Assay (LLNA) according to the OECD Guideline 429 and EU Method B.42. The individual approach was used in this test whereby the lymph nodes of each animal were evaluated individually (in comparison to a pooled test group approach). The maximum attainable test item concentration, resulting in a homogenous formulation in an appropriate vehicle, was examined.

A preliminary solubility test was performed to select a suitable vehicle. The maximum attainable test concentration based on solubility was 25 % (w/v) in aqueous 1 % Pluronic. No higher test concentration was available in this test.

Based on results of a preliminary irritation/toxicity test 25 % was selected as the highest test concentration in the main test.

In the main test, 35 female CBA/Ca mice were allocated to seven groups of five animals each:

-four groups received cesium nitrate at 25 %, 10 %, 5 % or 2.5 %,

-the negative control group received the vehicle (1 % Pluronic) only,

-the positive control group received 25 % alpha-Hexylcinnamaldehyde

-the negative control group for the positive control group received Acetone: Olive oil 4:1 mixture (v/v/) (AOO) only.

Each substance was applied on the external surface of each ear (25 µL/ear) of the animals for three consecutive days (Day 1, 2 and 3).

There was no treatment on Days 4, 5 and 6. On Day 6, the cell proliferation in the local lymph nodes was measured by determining incorporation of tritiated methyl thymidine (3HTdR) and the obtained values were used to calculate stimulation indices (SI). No mortality was observed during the test. No local effects at the application sites (ears) were observed in any treatment group. Larger lymph nodes than the control were observed in the positive control group only. No statistically significant lymphoproliferation was observed in any group treated with the test item. The obtained SI values for the test item were 0.91, 0.72, 0.97 and 1.05 at concentrations of 25 %, 10 %, 5 % and 2.5 %, respectively. No dose-related response was observed. The positive control item induced the appropriate stimulation (SI = 11.82), thus confirming the validity of the assay. Since the mean SI value was below 3 at the maximum attainable test concentration of 25 % and at concentrations of 10 %, 5 % and 2.5 % and no dose-related response was observed, the test item was considered to be a non-sensitiser in the LLNA.