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Toxicological information

Neurotoxicity

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Description of key information

Hazards identified by BG Chemie Toxicological Evaluation, last updated: 06/2000:
"Technical-grade diphenyl cresyl phosphate may cause delayed polyneuropathy (ataxia, paralysis of the extremities, histopathological changes of the nerve tissue), particularly in chickens. Only the o-cresyl isomer of diphenyl cresyl phosphate is neurotoxic, as are diphenyl cresyl mixtures which contain the o-cresyl isomer. This is the only isomer capable of forming phenyl saligenin phosphate, a metabolite which is considered responsible for the neurotoxic effects. On single and multiple administration of diphenyl o-cresyl phosphate, hens have been observed to develop signs of neurotoxicity 2 to 3 weeks after dosing, including limping, ataxia and paralysis of the extremities as well as demyelinisation in the cerebrum, the cerebellar folia and the spinal cord. In addition, there are reports that the enzyme, NTE (neuropathy target esterase), is inhibited in the brain, the spinal cord and the peripheral nerves. This inhibition occurs within 24 hours. In the rat, single intraperitoneal administration of 300 mg and of 150 mg diphenyl cresyl phosphate leads to a reversible decrease in plasma pseudocholinesterase activity. The findings obtained with o-cresyl-containing diphenyl cresyl phosphate, however, are now only of historical interest. Today, the product is manufactured from synthetic cresol which contains no o-isomers and hence is not neurotoxic. "
Updated relevant information: None

Key value for chemical safety assessment

Additional information

Justification for classification or non-classification

Based on the available studies, the test substance needs no classification for neurotoxicity according to EU guidelines.