Cesium formate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 13, 2008 to October 28, 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Limited, Bicester, Oxon, UK
- Age at study initiation: 8-12 week
- Weight at study initiation: 15-23 g
- Housing: Individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): 2014 Teklad Global Rodent diet supplied by Harlan Teklad, Blackthorn, Bicester, Oxon, UK
- Water (e.g. ad libitum): Tap water, ad libitum
- Acclimation period: 5 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 30-70 %
- Air changes (per hr): 15 air changes per h
- Photoperiod (hrs dark / hrs light): 12 h light/12 h dark cycle

Vehicle:

other: Ethanol/distilled water (7:3)

Concentration:

50, 25 and 10 % w/w in ethanol/distilled water (7:3)

No. of animals per dose:

Four

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: Test substance solution was prepared in ethanol/distilled water (7:3)
- Irritation: No
- Lymph node proliferation response: No

Preliminary Screening Test: Test substance (25 µL) at concentration of 50 % w/w in ethanol/distilled water (7:3) was applied to the dorsal surface of each ear of the mouse for 3 consecutive days (Days 1, 2 and 3) and then observed for systemic toxicity twice daily on Days 1, 2 and 3 and once daily on Days 4, 5 and 6. Body weights were recorded on Day 1 and 6.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: Stimulation index ≥ 3

INDUCTION EXPOSURE
- No. of exposures: Three
- Exposure period: Three consecutive days (Day 1-3)
- Test groups: 50, 25 and 10 % w/w
- Control group: Ethanol/distilled water (7:3)
- Site: Dorsal surface of the ear
- Frequency of applications: Once daily
- Duration: 1-3 d
- Concentrations: 50, 25 and 10 % w/w in ethanol/distilled water (7:3)

CHALLENGE CONTROLS
Negative control (vehicle): Ethanol/distilled water (7:3), four female mice
Positive control: α-Hexylcinnamaldehyde, Tech, 85 % (5, 10 and 25 % w/w in ethanol/distilled water 7:3), five animals in each group

TREATMENT PREPARATION AND ADMINISTRATION:
25 μL of the test substance (50, 25 and 10 % w/w) was applied to the entire dorsal surface of each ear of individual mouse using an automatic micropipette. The application was repeated on days 2 and 3. On day 6, 250 μL phosphate buffered saline (PBS) containing 20 μCi of 3H-methyl thymidine (3H-TdR: 80 μCi/mL, specific activity 2.0 Ci/mmol, GE Healthcare UK Ltd) was injected into the tail vein of each experimental mouse. Five hours later, all mice were killed by CO2 asphyxiation and the draining Auricular lymph node of each ear was excised into PBS. A single cell suspension of lymph node cells (LNC) bilaterally from individual mouse is prepared by gentle mechanical disaggregation through 200 μm-mesh stainless steel gauze. Lymph node cells are washed with an excess of PBS and precipitated with 5% trichloroacetic acid (TCA) at 4 °C for 18 h. Pellets were re-suspended in 1 mL TCA and transferred to scintillation vials containing 10 mL of scintillation fluid for 3H-counting. The number of radioactive disintegrations per minute (DPM) was measured using the Beckman LS6500 scintillation system.

Positive control substance(s):

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

Positive control results:

The stimulation Index for α-Hexylcinnamaldehyde at concentrations of 5, 10, 25 % v/v in ethanol/distilled water 7:3 was as follows:

Concentration (% v/v) in ethanol/distilled water 7:3 Stimulation Index Result
5 4.70 Positive
10 10.57 Positive
25 17.76 Positive
where, Stimulation Index = Mean radioactivity of each treatment group / Mean radioactivity of vehicle control group

Key result

Parameter:

SI

Value:

0.97

Test group / Remarks:

10% w/w

Key result

Parameter:

SI

Value:

1.02

Test group / Remarks:

25% w/w

Key result

Parameter:

SI

Value:

1.52

Test group / Remarks:

50% w/w

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Vehicle = 3761.32 dpm Test material (10 % w/w) = 3638.16 dpm Test material (25 % w/w) = 3838.19 dpm Test material (25 % w/w) = 5700.98 dpm

Neither mortality nor any signs of systemic toxicity were observed in the test or control animals during the study. No significant changes in the body weight were observed in the animals during the study.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the study conditions the test substance was determined to be non-sensitizing.

Executive summary:

A study was conducted to determine the skin sensitisation potential of the test substance in CBA/Ca strain mice according to OECD Guideline 429 and EU Method B.42 (Local Lymph Node Assay), in compliance with GLP. In the preliminary screening test, neither mortality nor clinical signs of toxicity were observed at concentration of 50% w/w, so this was selected as the highest dose for the main study. In the main study, three groups, each of four animals, were applied with 25 µL of the test substance (10, 25 and 50% w/w in ethanol/distilled water 7:3) to the entire dorsal surface of each ear. The negative control (vehicle) group was applied with ethanol/distilled water (7:3). Historic data of α-hexylcinnamaldehyde (5, 10 and 25% w/w in ethanol/distilled water 7:3) was used as the data for positive control group. The Stimulation Index for 10, 25 and 50% w/w of the test substance were observed to be 0.97, 1.02 and 1.52, respectively. The disintegrations per minute (dpm) for vehicle, 10, 25 and 50% w/w of the test substance were observed to be 3,761.32, 3,638.16, 3,838.19 and 5,700.98, respectively. The dpm/node for vehicle, 10, 25 and 50% w/w of the test substance were 470.17, 454.77, 479.77 and 712.62, respectively. Neither mortality nor symptoms of systemic toxicity were observed in the vehicle and treatment groups. Also, no significant changes in the body weights were seen in the animals during the study. Under the study conditions, the test substance was determined to be non-sensitizing (Sanders, 2009).

Reference 2

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A study was conducted to determine the skin sensitisation potential of the test substance in CBA/Ca strain mice according to OECD Guideline 429 and EU Method B.42 (Local Lymph Node Assay), in compliance with GLP. In the preliminary screening test, neither mortality nor clinical signs of toxicity were observed at concentration of 50% w/w, so this was selected as the highest dose for the main study. In the main study, three groups, each of four animals, were applied with 25 µL of the test substance (10, 25 and 50% w/w in ethanol/distilled water 7:3) to the entire dorsal surface of each ear. The negative control (vehicle) group was applied with ethanol/distilled water (7:3). Historic data of α-hexylcinnamaldehyde (5, 10 and 25% w/w in ethanol/distilled water 7:3) was used as the data for positive control group. The Stimulation Index for 10, 25 and 50% w/w of the test substance were observed to be 0.97, 1.02 and 1.52, respectively. The disintegrations per minute (dpm) for vehicle, 10, 25 and 50% w/w of the test substance were observed to be 3,761.32, 3,638.16, 3,838.19 and 5,700.98, respectively. The dpm/node for vehicle, 10, 25 and 50% w/w of the test substance were 470.17, 454.77, 479.77 and 712.62, respectively. Neither mortality nor symptoms of systemic toxicity were observed in the vehicle and treatment groups. Also, no significant changes in the body weights were seen in the animals during the study. Under the study conditions, the test substance was determined to be non-sensitizing (Sanders, 2009).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available in vivo data suggests that the substance is not sensitizing. No classification for this endpoint is therefore warranted according to CLP (EC 1272/2008) criteria.