@article {INABA69, author = {T. INABA and T. UMEDA}, title = {BILIARY EXCRETION OF DIPHENYLHYDANTOIN IN THE RAT}, volume = {3}, number = {2}, pages = {69--73}, year = {1975}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {The role of biliary excretion in the dose-dependent elimination of diphenylhydantoin (DPH) was investigated in the rat. During 6 hr, following iv injection of 10 mg of [14C]DPH per kg, 28\% of the radioactivity was excreted in bile and following 1 mg/kg, 54\% was excreted. The rate of biliary excretion of total radioactivity following the higher dose of DPH reached a plateau and remained constant over a period of 6 hr, whereas, with the lower dose, the excretion was a first order process (half-life 165 {\textpm} 34 (SE) min). When the major metabolite of DPH. 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH, 14C-labeled), was administered (1 and 10 mg/kg iv), the rates of biliary excretion of total radioactivity were first order, with half-lives of 49 {\textpm} 3 and 57 {\textpm} 4 min, respectively. Therefore, the conjugation of p-HPPH and the transfer of the conjugate from liver cells into bile were not saturable with the two doses studied. The data are consistent with the assumption that the dose-dependent elimination of DPH is due to the saturable conversion of DPH to p-HPPH. Copyright {\textcopyright} 1975 by The American Society for Pharmacology and Experimental Therapeutics}, issn = {0090-9556}, URL = {https://dmd.aspetjournals.org/content/3/2/69}, eprint = {https://dmd.aspetjournals.org/content/3/2/69.full.pdf}, journal = {Drug Metabolism and Disposition} }