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Description of key information

An appropriate oral repeated dose toxicity study is available in methods comparable to OECD guideline 407.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Dose descriptor:
NOAEL
50 mg/kg bw/day
Study duration:
subchronic
Species:
rat

Additional information

A repeat dose study was performed in male rats as a part of a Reproduction/Developmental Toxicity Screening test. 10 males per dose were treated via oral gavage with 25, 50 and 100 mg/kg bw MMP for 28 days. 50 kg bw was determined to be the NOAEL, based on four males in the high dose group displaying a minimal to slight hyperplasia of the forestomach squamous epithelium partly associated with a minimal to slight hyperkeratosis and minimal inflammatory cell infiltrations. Although these effects were considered to be treatment related, proliferative lesions of the rodent non-glandular stomach region are relatively common in gavage and feeding studies and are not relevant to humans because of lack of a forestomach. Liver weights relative to body weight and brain weight were dose-dependently increased in the mid and high dose groups, but in the absence of a histological correlation the increases were considered toxicologically irrelevant. However, the study was conducted for 28-days (instead of a 90-days) and failed to report on possible adverse histological effects at dose levels above 100 mg/kg bw. A classification for the repeat dose toxicity endpoint cannot be made due to insufficient data.

Justification for classification or non-classification

Specific target organ toxicity repeated - Reason for no classification: inconclusive.

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