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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Data is from publication.

Data source

Reference
Reference Type:
publication
Title:
Assessment of the sensitizing potency of preservatives with chance of skin contact by the loose-fit coculture-based sensitization assay (LCSA)
Author:
Anna Sonnenburg • Maximilian Schreiner, Ralf Stahlmann
Year:
2015
Bibliographic source:
Arch Toxicol (2015) 89:2339–2344

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: As mention below
Principles of method if other than guideline:
To evaluate the skin sensitizing potential of isopropyl 4-hydroxybenzoate in vitro method of loose-fit coculture-based sensitization assay(LCSA).
GLP compliance:
not specified
Type of study:
other: loose-fit coculture-based sensitization assay (LCSA)
Justification for non-LLNA method:
Not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Isopropyl 4-hydroxybenzoate
EC Number:
224-069-3
EC Name:
Isopropyl 4-hydroxybenzoate
Cas Number:
4191-73-5
Molecular formula:
C10H12O3
IUPAC Name:
propan-2-yl 4-hydroxybenzoate
Test material form:
solid
Details on test material:
- Name of test material (as cited in study report): isopropyl 4-hydroxybenzoate
- Molecular formula : C10H12O3
- Molecular weight : 180.202 g/mole
- Smiles notation : c1(C(OC(C)C)=O)ccc(O)cc1
- InChl : 1S/C10H12O3/c1-7(2)13-10(12)8-3-5-9(11)6-4-8/h3-7,11H,1-2H3
- Substance type:Organic
- Physical state:Solid
Specific details on test material used for the study:
- Name of test material: Isopropyl p-hydroxybenzoate
- IUPAC name: isopropyl 4-hydroxybenzoate
- Molecular formula: C10H12O3
- Molecular weight: 180.202 g/mol
- Substance type: Organic
- Physical state: No data

In vitro test system

Details on the study design:
Skin sensitisation (In vitro test system) - Loose-fit coculture-based sensitization assay
Keratinocytes were isolated from skin which was received as residual material from plastic surgery. Peripheral blood mononuclear cells were enriched from buffy coats by density centrifugation. Cells were cocultured in serum-free Keratinocyte growth medium 2 on 12-well cell culture plates. Increasing concentrations of test substances were tested until significant cytotoxicity or decreased solubility occurred.

Viability of cells was measured by 7-AAD staining. Each substance was tested with three different DC-rc/KC-donor pairs to account for interindividual variability

The LCSA is based on a co -culture of primary human keratinocytes and allogenic dendritic cell-related cells (DC-rc) which upregulate the expression of the maturation marker CD86 when incubated with sensitizers.

Results and discussion

Positive control results:
At least 1.4-fold increase in CD86-expression compared to zero controls.

In vitro / in chemico

Results
Key result
Run / experiment:
other: In Loose-fit coculture-based sensitization assay ,the EC50 value for test material was 157.84 μmol/l.
Parameter:
other: EC50
Remarks:
Substance concentration causing a half-maximal increase in CD86-expression
Value:
157.84
Positive controls validity:
valid
Remarks on result:
positive indication of skin sensitisation
Other effects / acceptance of results:
OTHER EFFECTS:
According to the study ,the EC50 value for test material was 157.84 μmol/l. which falls into the wekk category of skin sensitization .



ACCEPTANCE OF RESULTS:
- Acceptance criteria met for positive control: yes

Any other information on results incl. tables

For categorization of sensitizing potency, the substance concentration which led to a half-maximal increase in CD86-expression (EC50sens) was assessed. Substances

were categorized as follows: half-maximal increase in CD86-expression

<12.5 μM: extreme;

 <50 μM: strong;

<100 μM: moderate;

>100 μM: weak.

Substances failing to elicit significant rise in CD86-expression up to the maximum test concentration were deemed non-sensitizers.

Paraben

EC50sens/(μmol/l)

Categorya

Isopropyl

157.84

Weak

Applicant's summary and conclusion

Interpretation of results:
other: sensitizing
Conclusions:
Isopropyl 4-hydroxybenzoate (4191-73-5) was observed for its skin sensitizing potential by Invitro method of loose-fit coculture-based sensitization assay (LCSA) .Isopropyl 4-hydroxybenzoate was considered to be sensitizing by Invitro method .
Executive summary:

Isopropyl 4-hydroxybenzoate (4191-73-5) was assessed for its skin sensitizing potential by In-vitro method. For this purpose isloosefit coculturebased sensitization assay(LCSA)was performed usingHuman keratinocytes.Human keratinocytes were used for the study. 12-well cell culture plates were used for the cocultured of the cell. Substances were tested for three different DC-rc/KC-donor pairs to account for interindividual variability.Sensitization potency of the test substances was assessed by flow cytometric analysis of the DC-rc maturation marker CD86. Determination of the concentration required to cause a half-maximal increase in CD86-expression (EC50sens) allowed a quantitative evaluation. Substances were categorized as follows: half-maximal increase in CD86-expression

<12.5 μM: extreme;

 <50 μM: strong;

<100 μM: moderate;

>100 μM: weak.

The EC50 sensitization was found to be 157.84 μmol/l forIsopropyl 4-hydroxybenzoate.Therefore,Isopropyl 4-hydroxybenzoate (4191-73-5)) was considered to be sensitizing to human keratinocytes cells.