OECD 442C Direct Peptide Reactivity Assay (DPRA)



The OECD 442C: Direct Peptide Reactivity Assay Test (DPRA) investigates the molecular initiating event of the AOP for skin sensitisation – haptenation. Utilising HPLC, the potential for the reactivity of a test substance to cysteine and lysine peptides is detected. Depletion of these peptides via test substance reactivity is used to support the discrimination between skin sensitisers and non-sensitisers.

DPRA has been validated, and laboratory proficiency under OECD 442C has been established at Gentronix. Services are available in both GLP and non-GLP formats.

OECD guidelineOECD 442C
Adverse Outcome Pathway Key EventNumber 1 – the molecular initiating event (MIE)
What is being assessedPeptide reactivity; the depletion of cysteine and lysine by test substance
Why is this importantCovalent binding of a substance to skin proteins is considered the first step in skin allergenicity
Test SystemHPLC-UV
Test Item Requirements 1 g

DPRA OECD 442C Proficiency Data

Test Chemicalin vivo classificationReactivity ClassDPRA ClassificationClassification Correct?
DNCBSensitiser (extreme)HighSensitiser
OxazoloneSensitiser (extreme)HighSensitiser
FormaldehydeSensitiser (strong)ModerateSensitiser
Benzyliden acetoneSensitiser (moderate)HighSensitiser
FarnesalSensitiser (weak)ModerateSensitiser
2,3-butanedioneSensitiser (weak)HighSensitiser
6-methyl coumarinNon-sensitiserNo/MinimalNon-sensitiser
Lactic acidNon-sensitiserNo/MinimalNon-sensitiser
4-methoxy acetophenoneNon-sensitiserNo/MinimalNon-sensitiser

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