Phosphorous ester

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The in vitro study was conducted according the OECD guideline 429 and the EU-Guideline 42 (LLNA- Local Lymphe Node Assay) to assess the skin sensitisation potential of GARDO TP. In the study (08/625 -03E) 16 female CBA/Ca mice (approximate age of 9 -10 weeks)were allocated into four groups. Three groups received the appropriate formulation of GARDO TP 10451 at concentration of 50 %, 25% or 10% in Acetone : Olive oil 4 : 1 mixture (AOO), the negative control group received the solvent (AOO). Each animal was dosed once a day on three consecutive days (day 0, 1 and 2). There was no treatment on Days 3 and 4. No mortality occurred but slight irritation with recovery was observed in all of the test item treated groups. A lymphoproliferative response (SI >= 3) was noted for GARDO TP 10451 at concentrations of 50% and 25%. The EC3 value of GARDO TP 10451 was 24.2% in this LLNA.

Thus, under the conditions of the LLNA assay, GARDO TP10451, dissolved in an appropriate solvent up to the maximum feasible concentration (50 %), was shown to have weak sensitisation potential (weak-sensitiser).

Although irritation was observed in the main assay it was not excessive. It is known that some non-sensitising irritant chemicals (such as sodium dodecyl sulphate) can give a slight positive response in the LLNA but there are also many irritants which do not give such a response. It is plausible that the slight increase in proliferation seen in this study could be secondary to the irritation effect, but there is no specific evidence to make this argument. So in line with the guidelines, the test item must be considered to be positive.

An in vivo study should be performed to verify this test result. For this reason, the performance of an in vivo study (Guinea-Pig Maximisation Test (GPMT)) is proposed and will be performed after approval by the authority.

Migrated from Short description of key information:
The test substance GARDO TP 10451 was examined in a skin sensitisation study in mice.
EC3: 24.2%

Justification for classification or non-classification

The EC3 value of GARDO TP 10451 derived from the skin sensitisation study (local lymph node assay) was 24.2% in CBA/Ca mice.

On the basis of published classification of contact allergens according to their potency, GARDO TP10451 can be ranked among weak sensitisers (100 >= EC3 (%) >= 10).