title: Availability of tritium from non-aqueous solutions of [1,2-3H]methyltestosterone, administered orally to rats.
abstract: The solvent-water distribution coefficients of 17 alpha-methyltestosterone have been determined in selected alkanes, alkanols and alkane-alkanol blends. The oral availability of tritium from solutions of [3H]methyltestosterone in these solvents and blends was studied in rats by measuring radioactivity in plasma, faeces and urine. Disappearance of radioactivity from the gut and biliary recirculation of 3H were also examined. Variation of the solvent led to marked changes in the absorption of radioactivity, suggesting a possible method of varying bioavailability from soft gelatin capsules. Neither distribution coefficients nor tritium concentrations changed significantly from one homologue to another, but there was a marked difference when the alkane series was compared with the alkanol series. Blends of octane and octanol, together with the pure solvents, provided a suitable spread of distribution coefficients and tritium concentrations, but no simple relationship could be established between the two properties.
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D004064:Digestive System / Q000378:metabolism; D007408:Intestinal Absorption; D008297:Male; D008777:Methyltestosterone / Q000378:metabolism*; D051381:Rats; D012995:Solubility; D012997:Solvents; D014316:Tritium / Q000378:metabolism*
chemical_list: D012997:Solvents; D014316:Tritium; D008777:Methyltestosterone