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Additional information

Ro 31 -9373/000 was tested in four strains of S. typhimurium (TA97, TA98, TA100 and TA102) in a standard plate incorporation and pre-inubation modification of the Ames test for mutagenic activity. The test material was disolved in DMSO and administered at concentrations ranging from 50 to 5000 ug/plate, in the presence or absence of metabolic activation in the form of rat liver induced S-9. Ro 31 -9373/000 was not toxic up to the maximal concentration tested in the standard plate incorporation assay but signs of toxicity were evident in the pre-incubation assay at 1666 ug/ml.

No increase in the his+ revertants was evident, PTH-decahydroamide was not found to be mutagenic under the conditions of this assay.

In a replicated assay to determine the effects of PTH-decahydroamide on the induction of chromosomal aberrations in cultured peripheral human lymphocytes, cultures were prepared with or without metabolic activation (rat liver S-9 mix) and tested using concentrations of up to 1000 ug/ml for 24 or 48 hour fixation periods. None of the concentrations evaluated gave a postive response under the test conditions. Vehicle and positive control cultures gave responses consistent with historical ranges and met the acceptance criteria for the assay. PTH-decahydroamide was not clastogenic under the conditions of this assay.

Short description of key information:
Negative responses are seen in an Ames test and a study of clastogencity in human pepripheral lymphocytes in vitro. Studies were performed in the presence and absence of metabolic activation.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Both in vitro studies - a clastogenicity investigation with human cultured peripheral lymphocytes and an Ames test using four strains of S.typhimurium - gave negative responses for mutagenicity. No classification is warranted for PTH-decahydroamide based on the available data.