(R)-thiazolidine-4-carboxylic acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.59 (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

GLP compliance:

yes

Type of study:

direct peptide reactivity assay (DPRA)

Test material

Test material information

Constituent 1

Reference substance name:

(R)-thiazolidine-4-carboxylic acid

EC Number:

252-106-3

EC Name:

(R)-thiazolidine-4-carboxylic acid

Cas Number:

34592-47-7

Molecular formula:

C4H7NO2S

IUPAC Name:

(R)-thiazolidine-4-carboxylic acid

Test material form:

solid: particulate/powder

In chemico test system

Details of test system:

cysteine peptide, (Ac-RFAACAA-COOH)

lysine peptide (Ac-RFAAKAACOOH)

Details on the study design:

Two experiments were performed. The Cys-peptide assay of experiment 1 was not valid,
because the mean peptide concentration was not in the range 0.50 ± 0.05 mM for the ref-
erence controls A and C (ACN). In Experiment 2 only the Cys-peptide assay was per-
formed and was valid.
The test item was incubated for 22 h at 25 °C together with Cys- and Lys-peptides, respec-
tively. The peptide concentration after the incubation period was measured using HPLC-UV.
Three replicates were prepared using 1:10 and 1:50 molar ratio of the test item with the Cys-
and Lys-peptides, respectively. Triplicate samples of the solvent without test item were in-
cubated and measured simultaneously.
For the calculation of the mean pepide depletion the value of the Lys-peptide depletion of
experiment 1 and of the Cys-peptide depletion of experiment 2 were used.

Results and discussion

In vitro / in chemico

Results

Results 1

Group:

test chemical

Run / experiment:

mean

Parameter:

mean cystein depletion

Value:

31.39 %

Results 2

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

lysine depletion

Value:

0.16 %

Results 3

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

cysteine depletion

Value:

62.62 %

Applicant's summary and conclusion

Conclusions:

The DPRA prediction is ”positive” according to the Cysteine 1:10/Lysine 1:50 pre-
diction model. Thus, under the experimental conditions reported, the test item L(-)-
Thiazolidine-4-carboxylic acid (TCA) shows a reactivity towards the two model syn-
thetic peptides.

The mean peptide depletion in the Cys-peptide and Lys-peptide assay was 31.39%, therefore the test item was classified with:
DPRA Prediction: Positive
Reactivity class: Moderate

Executive summary:

Two experiments were performed. The Cys-peptide assay of experiment 1 was not valid, because the mean peptide concentration was not in the range 0.50 ± 0.05 mM for the ref-
erence controls A and C (ACN). In Experiment 2 only the Cys-peptide assay was performed and was valid.
As the peptide assays are independent, for calculation of the mean peptide depletion, the results of the valid Lys-peptide assay of experiment 1 and the results of the Cys-peptide assay of experiment 2 were used.
The main peptide depletion was 31.39%.
The mean area ratio of the positive control 2,3-Butanedione in the Lys-peptide assay in experiment 1 was 85% and therefore not in the required range 90 – 110%. This value is a
sign for co-elution and peak purity and the co-elution control shows a small peak at 258 nm. The mean area ratio is no acceptance criterion and no co-elution is observed at 220 nm. Therefore, the mean area ratio has no influence on the result of the peptide depletion measured at 220 nm.
The DPRA prediction is ”positive” according to the Cysteine 1:10/Lysine 1:50 prediction model (see chapter 10.3). Thus, under the experimental conditions reported, the test item
L(-)-Thiazolidine-4-carboxylic acid (TCA) shows a reactivity towards the two model synthetic peptides.
This assignment supports the discrimination between skin sensitisers and non-sensitisers in the framework of an integrated approach (IATA).
For sensitising potency assessment within an IATA, the test item L(-)-Thiazolidine-4-carboxylic acid (TCA) could be assigned to the reactivity class that covers moderate reactivity under the conditions of this study.