Cesium tungsten oxide

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Adopted 22 Jul 2010

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Commission Regulation (EC) No. 440/2008

Deviations:

no

Species:

mouse

Strain:

CBA/Ca

Remarks:

CBA/CaOlaHsd

Sex:

female

Key result

Parameter:

SI

Value:

ca. 1.07

Test group / Remarks:

10% (w/w) in propylene glycol

Remarks on result:

other: Result: Negative

Key result

Parameter:

SI

Value:

ca. 0.96

Test group / Remarks:

25% (w/w) in propylene glycol

Remarks on result:

other: Result: Negative

Key result

Parameter:

SI

Value:

ca. 1.58

Test group / Remarks:

50% (w/w) in propylene glycol

Remarks on result:

other: Result: Negative

Cellular proliferation data / Observations:

CLINICAL OBSERVATIONS: none

BODY WEIGHTS: no significant changes

Disintegrations per minute, Disintegrations per minute/node, Stimulation Index, and Result

Concentration (% w/w) in propylene glycol	dpm	dpm/node^a	Stimulation Index^b	Result
Vehicle	6946.46	868.31	NA	NA
10	7433.47	929.18	1.07	Negative
25	6665.40	833.18	0.96	Negative
50	10986.49	1373.31	1.58	Negative

dpm = disintegrations per minute

^a= dpm/node obtained by dividing the dpm value by 8 (the total number of lymph nodes)

^b= Stimulation Index of 3.0 or greater indicates a positive result

NA = not applicable

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

OECD 429 (2017) - In a dermal sensitization study with the test item: propylene glycol young female adult mice (CBA/CaCrl) were tested using the Local Lymph Node Assay (LLNA).

Three groups were treated with 25 μL of the test item in solution in the vehicle at concentrations of 50, 25 and 10 % w/w. A further group was treated with the vehicle alone. A concurrent positive control test was also performed with the known sensitiser.

The Stimulation Index, expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group, was determined for each treatment group.

The test was considered valid. 

The test item did not elicit a Stimulation Index ≥ 3 when at any testing level. The test item was therefore considered not to be a sensitiser under the conditions of the test. 

Based on the condition of this study, the test item was not classified as a sensitiser in accordance with Regulation (EC) No 1272/2008.

 

The study was conducted on the particulate nanoform (i.e. not the dissolved form). Based on dissolution study results (Rosenfeldt, 2021, Section 4) this aligns with the draft ECHA guidance (Appendix R7-1 for nanoforms applicable to Chapter R7a and R7c Endpoint specific guidance, draft v3.0, 2021), whereby testing on the nanoform should be conducted if the nanoform is not highly soluble in water (>33,3 g/L) and/or does not have a half-life of water dissolution ≤ 10 min (Appendix R7-1 for nanoforms applicable to Chapter R7a and R7c Endpoint specific guidance, draft v3.0, 2021; Figure 1).  This is further supported by the lack of dissolution seen in any vehicle.

Justification for classification or non-classification

The simulation index during the an OECD 429 study was < 3 %.  Therefore, in accoradance with Regualtion (EC) 1272/2008 (CLP), the test item is not a skin sensitiser.