[Pharmacokinetics of AR-L 115 BS in the rat (author's transl)].

Following i.v. and p.o. administration, blood concentration, tissue distribution and excretion as well as metabolic pattern was investigated in rats for 14C-labelled 2-[(2-methoxy-4-methylsulfinyl)phenyl]1H-imidazo[4,5-b]pyridine (AR-L 115BS). The absorption following oral application was so rapid that no further rise in blood level could be seen 5 min after administration. The radioactivity was eliminated from blood with a half-life of 1 h. Only very low levels were measurable after 8 h. There was a rapid distribution into the tissues, especially into the live and the concentration of radioactivity in skeletal and heart muscle was comparably high. The elimination of radioactivity via bile and urine was also rapid. After intravenous or intraduodenal administration 70% and 63% of the dose were excreted via bile over 6 h. This indicates a good enteral absorption. During metabolism especially polar metabolites were found but only a few conjugates were identified. The metabolite level increases in the plasma shortly after oral application. The metabolites detected in plasma are also seen in bile and urine. Only small amounts of parent substance were detected in bile and urine.