Dose-Dependent Intestinal Absorption and Significant Intestinal Excretion (Exsorption) of the β-Blocker Pafenolol in the Rat

摘要: The elimination of [3H]pafenolol and metabolites was investigated in fasted fed rats. Separate groups received intravenous doses (0.3 3.0 µmol/kg) oral (1 25 µmol/kg). After iv administration pafenolol, the excretion unchanged drug into urine feces about 50 25–30% given dose, respectively. predominating mechanism for pafenolol intestinal (exsorption) directly from blood gut lumen, since only 3% a dose recovered as bile. When raised 1 to µmol/kg, mean (±SD) bioavailability, calculated data, increased 14 ± 9 30 11% (P < 0.05) starved rats 3 16 animals. In parallel, fraction absorbed (fa) 19 31 10% 4 5% animals, This indicates that low bioavailability is due primarily poor uptake.