COMPARATIVE ENTRY OF CARBOPLATIN AND SUCROSE IN ENDOLYMPH IN THE RAT COCHLEA

The permeability of the perilymphatic-endolymphatic interface for carb oplatin was determined after lateral cerebral ventricle infusion of ra dioactive carboplatin ine[1,1-cyclobutane-1-C-14-dicarboxylate]platinu m) to rats. [C-14]sucrose, a similar weight molecule was used for comp arison of the kinetics in the inner ear fluids. C-14-radioactivity was measured in perilymph and endolymph. The rate of elimination of the t racers from perilymph was equivalent indicating no difference in trans port across the blood-perilymph barrier. The transport from perilymph to endolymph was very restricted for both substances. The present stud y indicates that the ototoxic effect of carboplatin cannot be explaine d by a specific endolymphatic transport mechanism.