Metabolic fate of FCE 22716, a new antihypertensive agent, and of its N-oxide (FCE 24220) in the rat.

[3H]-FCE 22716 and [3H]-FCE 24220 were given both orally and intravenously to the rat. Radioactivity was mainly eliminated by the faecal route after oral administration in both cases. After intravenous administration, renal excretion was twice the faecal one in the case of FCE 22716, whereas for FCE 24220 the two routes were equal. In urine FCE 22716 was eliminated almost completely unchanged after both oral and intravenous administration. FCE 24220 was extensively reduced to FCE 22716 after oral administration, whereas after intravenous treatment, this reduction, although important, was not complete.