Pharmacokinetics and pharmacodynamics of cicaprost in healthy volunteers after oral administration of 5 to 20 micrograms.

In a Phase I study, the tolerability, pharmacodynamics and pharmacokinetics of cicaprost have been investigated in 6 male volunteers given 5, 10, 15 and 20 micrograms as tablets of the beta-cyclodextrin clathrate. Individual inhibition of platelet aggregation and changes in facial colour (measured by chromametry) were dose-dependent and reached a maximum 30 to 60 min post-dose. The maximum inhibition of platelet aggregation was about 40%. After 3 to 4 h pre-treatment values had returned. Blood pressure remained within the normal range. The peak plasma level of cicaprost was reached within 15 to 90 min after drug intake. Both Cmax- and AUC were individually dose-dependent. The terminal half-life in plasma of cicaprost was approx. 1 h, and its total clearance amounted to 4-7 ml.min-1.kg-1. The time courses of the plasma levels and of the pharmacodynamic actions were in agreement. Interindividual differences were observed in the occurrence of unwanted effects (e.g. headache). Thus, cicaprost is an orally available PGI2-mimetic, for which effects on platelet aggregation and vascular perfusion have been demonstrated in healthy volunteers after doses of 5 to 15 micrograms.