Studies on the absorption, distribution, metabolism and excretion of 1-(3,5-dihydroxyphenyl)-1-hydroxy-2-[(4-hydroxyphenyl)isopropylamino]-ethane hydrobromide (Th 1165 a, fenoterol hydrobromide) in mice.
Absorption, distribution, metabolism and excretion of 1-(3,5-dihydroxyphenyl)-1-hydroxy-2-[(4-hydroxyphenyl)-isopropylamino]-ethane labelled with 3H (3H-fenoterol) were investigated in mice. After oral administration, 3H-fenoterol was absorbed quickly, reaching a maximum concentration level within 0.5 h after administration, and decreased thereafter with a half-life of about 2 h. Concerning the distribution in tissues after oral administration, digestive tracts showed the highest radioactivity concentration, with lesser concentrations in the kidneys, trachea and liver. The radioactivity concentrations in the other tissues were lower than or equal to that in blood. The concentration in brain tissue was especially low. 24 h after administration, radioactivity was hardly observed in any of the tissues except for intestinal contents. The rates of excretion in urine and in feces in 72 h were ca. 81% and 16%, respectively, with i.v. administration and ca. 45% and 45%, respectively, with oral administration. Metabolites were investigated in urine, serum, liver and kidneys. With every sample the mother compound was hardly observed at all, and most of what was observed were conjugates of fenoterol. The binding rate of 3H-fenoterol with serum protein was investigated with a gel-filtration method. As a result, the binding rate with serum protein was 3--5%.
D000818:Animals; D001711:Biotransformation; D001798:Blood Proteins / Q000378:metabolism; D004983:Ethanolamines / Q000378:metabolism*; D005243:Feces / Q000032:analysis; D005260:Female; D005280:Fenoterol / Q000378:metabolism* / Q000652:urine; D007408:Intestinal Absorption; D051379:Mice; D008813:Mice, Inbred ICR; D011485:Protein Binding; D014018:Tissue Distribution
D001798:Blood Proteins; D004983:Ethanolamines; D005280:Fenoterol