[The pharmacokinetics of dihydroergocristine after intravenous and oral administration in rats].

The pharmacokinetic properties of dihydroergocristine (DHEC, CAS 17479-19-5) were investigated in rats using a specific radioimmunoassay technique specific for non-metabolized drugs. DHEC, administered intravenously at the dose of 6 mg/kg, showed a plasma profile conforming to an open two-compartment pharmacokinetic model with a long terminal half-life (t1/2 = 13.6 h). DHEC kinetics after oral administration (6 mg/kg) showed two peaks. The first peak (C = 37 micrograms/l) occurred at the first collection point (0.5 h) indicating a quick absorption of the drug. The second peak (C = 34 micrograms/l) occurred at 2 h and may be considered an indication of an enterohepatic cycle. A long terminal half-life (t1/2 = 18.1 h) was observed. An extensive biotransformation of DHEC was indicated by an almost complete absence of unchanged drug in the urine and a high systemic clearance (2.65 l.h-1 x kg-1). A large volume of distribution (52 l.kg-1) was calculated.