Neurotoxic properties of musk ambrette.

Musk ambrette (2,6-dinitro-3-methoxy-4-tert-butyltoluene), a nitro-musk compound widely used as a fixative in fragrance formulations and found to a lesser degree in flavor compositions, produces hindlimb weakness when administered in the diet or applied to skin of rats for periods up to 12 weeks. Underlying neuropathologic changes consist of primary demyelination and distal axonal degeneration in selected regions of the central and peripheral nervous system. Murine neurological disease induced by musk ambrette occurs at doses well above estimated maximum daily human exposure. Lifetime experimental neurotoxicology studies using lower concentrations of musk ambrette for prolonged periods would be needed for the estimation of human risk.