The Tissue Distribution of ³H‐Terbutaline (Bricanyl®) in Mice

Abstract

Abstract The tissue distribution of 3 H‐terbutaline. a new β‐stimulaing tagent, was investigated in mice by whole‐body autoradiography as well as by determinations of unchanged and biotransformed terbutaline in serum, lung, heart, and liver. The radioactivity was localized mainly to the extracellular space and the levels in most tissues were of the same magnitude as that in blood; no uptake and storage of the drug was observed. Neither terbutaline nor its metabolites penetrated the blood‐brain barrier or the placenta barrier. High relative concentrations of unchanged drug were found in the tissues studied, especially in the lung. A low rate of biotransformation is considered to be the cause for this.