Delayed elimination of the ototoxic compound atoxyl from the inner ear

Whether an active accumulation of ototoxic substances or their metabolites occurs in the cochlea, or whether there exists a delayed elimination of these products from the endo-and perilymphatic fluids, following a passive equilibrium between the blood and the body tissues, is still a subject for discussion. To investigate the cochlear distribution of an ototoxic substance and its elimination rate, compared to other organs in the body, atoxyl, with known ototoxic effects (Anniko and Wersäll, 1975a, b; Anniko, 1976a, b) was used as a test substance. The neutron activation analysis technique was used to measure the atoxyl concentration in various parts of the body (cochlea, blood, muscle, kidney and cortical femoral bone) after various lengths of time following a subcutaneous injection of 100 mg/kg b.w. of atoxyl. Atoxyl was retained in the cochlea for a long period and a delayed elimination occurred from the inner ear. The excretion of atoxyl was likely to appear via the kidneys.