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An In Vitro Skin Irritation Test (SIT) using the EpiDerm Reconstructed Human Epidermal (RHE) Model
Published on: July 13, 2009
Performance standards and alternative assays: practical insights from skin sensitization
Susanne N Kolle1, David A Basketter, Silvia Casati
1BASF SE, Experimental Toxicology and Ecology, Ludwigshafen, Germany. susanne.kolle@basf.com
Regulatory Toxicology and Pharmacology : RTP
|January 3, 2013
Summary
Performance standards (PS) streamline toxicity test validation. However, the standard local lymph node assay (LLNA) may not always meet its own PS, highlighting the need to account for biological variability in alternative testing.
Area of Science:
- Toxicology
- Regulatory Science
- In vitro testing
Background:
- Performance standards (PS) are crucial for efficient validation of alternative toxicity test methods.
- The Organisation for Economic Co-operation and Development (OECD) has established harmonized PS for the local lymph node assay (LLNA).
Purpose of the Study:
- To evaluate the performance of a lymph node cell count alternative (LNCC) method against the regulatory LLNA and its associated PS.
- To identify factors influencing the discrepancies observed between test methods and performance standards.
Main Methods:
- Simultaneous conduct of the regulatory LLNA and the LNCC method.
- Comparison of results from both methods and against established PS.
- Analysis of discrepancies, particularly for "borderline" substances.
Main Results:
- The LNCC method yielded results comparable to the concurrent LLNA.
- Discrepancies were noted between the PS, LLNA, and LNCC, primarily with "borderline" substances.
- Biological variability in both endpoints significantly influenced the observed results.
Conclusions:
- The standard LLNA may not consistently meet its own performance standards, indicating potential issues with the standards or the assay's inherent variability.
- Biological variability is a key factor to consider when evaluating toxicity test results, especially for substances near hazard classification thresholds.
- Variability in standard assays should be considered when selecting reference chemicals for performance standards to ensure robust validation of new methods.
