Abstract
Macroautoradiographic studies on distribution of14C-pipemidic acid in the guinea pig ear were performed after administration of the drug to provide its disposition for its application in the otolaryngological field. Petrosal bone, cochlea and auditory ossicles contained extremely low levels of14C-pipemidic acid; blood, mucous tissues of tympanic cavity and tympanic membrane, low levels; tissues of external ear, moderate levels; and outer surface tissues of petrosal bone possibly including periosteum, significant levels. These otological tissue distributions of pipemidic acid suggest the effective applicability of the drug in the field.