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Toxicological information

Skin sensitisation

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Administrative data

skin sensitisation: in vitro
Type of information:
experimental study
Adequacy of study:
key study
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
other: OECD Test Guideline 442E: human Cell Line Activation Test (h-CLAT)
Version / remarks:
The study was performed using the h-CLAT method as detailed in XCellR8 SOP L0094 which complies with OECD TG 442E and EURL ECVAM DB-ALM Protocol No. 158.
Principles of method if other than guideline:
To determine the In Vitro skin sensitisation potential of Crodateric CYAP-100 using the human Cell Line Activation Test (h-CLAT) method as detailed in OECD TG 442E (adopted 29 Jul 2016) and also in EURL ECVAM DB-ALM Protocol No. 158 human Cell Line Activation Test (h-CLAT); Skin Sensitisation and Allergic Contact Dermatitis (Issued: 01 Jul 2015).
GLP compliance:
yes (incl. QA statement)
Type of study:
other: human Cell Line Activation Test (h-CLAT)

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium 2-heptyl-2,3-dihydro-3-(2-hydroxyethyl)-1H-imidazole-1-propionate
EC Number:
EC Name:
Sodium 2-heptyl-2,3-dihydro-3-(2-hydroxyethyl)-1H-imidazole-1-propionate
Cas Number:
Molecular formula:
sodium 3-[2-heptyl-3-(2-hydroxyethyl)-2,3-dihydro-1H-imidazol-1-yl]propanoate
Test material form:
Details on test material:
Product name: Crodateric CYAP
Batch Number: PS-196-555
Appearance: The sample has been produced from drying of the aqueous solution of the material as sold commercially. It is observed to be a brown sticky solid
Specific details on test material used for the study:
Supplier Croda
Test Item Name Crodateric CYAP-100
Supplier Code DEV080817DS3
Supplier Batch/Lot Number PS-196-562
CAS Number 70983-43-6
Purity 99.41% (from CofA)
Expiry Date 3 July 2018
Physical State Solid, Dark
Storage Conditions Room Temperature
Solubility Ethanol, Isopropanol
XCellR8 Test Item Code CRO1026
Study Test Item Code TA1

In vitro test system

Details on the study design:
Skin sensitisers have been reported to induce the expression of cell membrane markers associated with Dendritic Cell (DC) activation. The h-CLAT method is an in vitro assay that quantifies these changes in cell surface marker expression (i.e. CD86 and CD54) on a human monocytic leukaemia cell line, THP-1 cells (a cell line that mimics DCs), following 24-hour exposure to the test item. The changes of surface marker expression are measured by flow cytometry following cell staining with fluorochrome-tagged antibodies. Cytotoxicity measurement is also conducted concurrently to assess whether upregulation of surface maker expression occurs at sub-cytotoxic concentrations. The relative fluorescence intensity of surface markers compared to the solvent/vehicle control are calculated and used in the prediction model, to support the discrimination between sensitisers and non-sensitisers.

Results and discussion

Positive control results:
Several criteria were not considered acceptable when assessing Runs 1 and 2. The responses were considered to be negative for sensitisation however the viability at the top concentration (348.84 µg/ml) was not less than 90%. In addition, the positive control in Run 2 did not produce an upregulated CD54 signal. Therefore, these runs were repeated using a higher dose in order to yield a cytotoxic response at the top concentration (552 µg/ml top concentration).
In the positive control (Nickel Sulphate), RFI values of both CD86 and CD54 should meet the positive criteria (CD86 RFI ≥ 150 and CD54 RFI ≥ 200) and cell viability should be greater than 50%. This was achieved and the control was considered to be a Pass.

In vitro / in chemico

Key result
other: The dose that gave 75% cell viability in µg/ml.
Vehicle controls validity:
not applicable
Negative controls validity:
not applicable
Positive controls validity:

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
In this study, the skin sensitisation potential of Crodateric CYAP-100 was assessed using the in vitro human Cell Line Activation Test (h-CLAT) method according to OECD Test Guideline 442E. After a 24h incubation with the test item the expression of cell surface markers CD54 and CD86 on THP-1 cells was measured by flow cytometry.
For Crodateric CYAP-100 the dose that yielded 75% cell viability was found to be 290.7 µg/ml. CD54 and CD86 expression were not upregulated above the sensitisation threshold by the test item at concentrations where the cell viability was ≥ 50% and therefore, Crodateric CYAP-100 was classified as a Non-Sensitiser as per the prediction model.