[Pharmacokinetics of tienocarbine in rats]

1,9-Dimethyl-7,8,9,10-tetrahydrothieno[3,2-e]pyrido[4,3-b] indole lactate (tienocarbine) 1, is absorbed and distributed very fast after a single oral or i.v. dose in rats. Half-lives (beta-phase) (i.v./p.o.) 1.9 and 2.2 h, respectively, VD 6.1/6.4 l/kg, oral bioavailability approx. 50%. After dosage for 28 days (2.5 mg/kg/d) all organs investigated contained tienocarbine, the N-desmethyl derivate was also found in lung and kidneys. 3 days after the last dose no 1 could be found in any organ. The quotient brain/blood is approx. 31 after single or repeated doses. With these low values of VD, the high brain/blood ratio and the constancy of these values tienocarbine differs from many other CNS active substances. 1 is intensively metabolised in rats; unchanged substance was found neither in urine nor in feces. Besides the N-desmethyl derivative, several as yet not identified metabolites occur.