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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vitro
Type of information:
experimental study
Adequacy of study:
key study
Study period:
27.08.2018 - 13.09.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method)
GLP compliance:
yes
Type of study:
activation of keratinocytes

Test material

Constituent 1
Chemical structure
Reference substance name:
Potassium hydrogen phthalate
EC Number:
212-889-4
EC Name:
Potassium hydrogen phthalate
Cas Number:
877-24-7
Molecular formula:
C8H6O4.K
IUPAC Name:
phthalic acid
Test material form:
solid: crystalline

In vitro test system

Details on the study design:
This in vitro study evaluates the potential of the test item Potassium Hydrogen Phthalate to activate the Nrf2 transcription factor (sensitizing potential) by using the LuSens cell line. This test is part of a tiered strategy for the evaluation of skin sensitization potential. Thus, data generated with the present Test Guideline should be used to support the discrimination be-tween skin sensitizers and non-sensitizers in the context of an integrated approach to testing and assessment.
The assay included a cytotoxicity range finder test (CRFT) and two independent experi-ments (experiment I and II) with a treatment period of 48 h. The CRFT was performed to detect a potential cytotoxic effect of the test item. Based on the results of this test the con-centrations for the two experiments were determined.
In the experiments, the highest nominal applied concentration (2000 μM) was chosen based on the results obtained in the CRFT. A geometric series (factor 1.2) of eleven dilutions thereof was prepared. DMEM (final concentration: 1 %) was used as solvent control and medium no. 3 as growth control. Lactic acid (5000 μM) was used as negative control and p-Phenylenediamine (80 μM) as positive control.

Results and discussion

Positive control results:
p-Phenylenediamine (80 μM) was used as positive control. The viability was above 70 % and a distinct increase in luciferase induction above 2.5 fold in comparison to the solvent control was detected. This luciferase induction is well within the historical data range of the positive control.

In vitro / in chemico

Results
Key result
Parameter:
other: Sensitisation
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
no indication of skin sensitisation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In conclusion, it can be stated that under the experimental conditions of this study, the test item, Potassium Hydrogen Phthalate, was negative in the LuSens assay and is therefore considered not to have the potential to activate the Nrf2 transcription factor (no sensitizing potential).
Executive summary:

This in vitro study was performed to investigate the potential of Potassium Hydrogen Phthalate to activate the Nrf2 transcription factor (sensitizing potential), by using the LuSens cell line.

The assay was performed in two independent experiments. 12 concentrations of the test item were evaluated. No cytotoxic effect was observed in all tested test item concentrations. Therefore, all tested concentrations could be evaluated for luciferase induction. In all tested concentrations of the test item no increase ≥ 1.5 fold in luciferase induction in comparison to the solvent control was measured.

Therefore, both experiments are clearly negative.

In conclusion, it can be stated that under the experimental conditions of this study, the test item, Potassium Hydrogen Phthalate, was negative in the LuSens assay and is therefore considered not to have the potential to activate the Nrf2 transcription factor (no sensitizing potential).