[Plasma levels, renal excretion and metabolism of orciprenaline after administration in sustained-release form (author's transl)].

A newly developed sustained-release form of orciprenaline-sulfate (Alupent) was tested in 13 patients. Determination of 3H-radioactivity in blood, urine and faeces was used to elucidate its pharmacokinetic properties. Maximum plasma levels of radioactivity were obtained between 8 and 12 h after administration. 10.7 +/- 2.5% of the administered radioactivity were excreted in urine over a period of 72 h. Orciprenaline was mainly excreted as the sulfate-conjugate. Approximately five percent of the radioactivity were excreted as 4,6,8-trihydroxy-N-isopropyl-tetrahydroisoquinoline--the condensation product of formaldehyde and orciprenaline.