The pharmacokinetics and bioavailability of urapidil. in vitro/in vivo correlations of different experimental formulations
Gielsdorf, W.; Nieder, M.; Molz, K.H.; Jaeger, H.; Haerlin, R.; Radtke, H.W.
Arzneimittel-Forschung 36(8): 1265-1267
1986
ISSN/ISBN: 0004-4172 PMID: 3778565 Document Number: 270170
The pharmacokinetic parameters, including the relative bioavailabilities of two experimental batches of a 60-mg urapidil slow release-capsule and a 30-mg urapidil drinking ampoule (Ebrantil) had to be evaluated in a randomized, three-period change-over study with 12 healthy volunteers after single dosing. The appropriate parameters for the capsule formulations were compared with their dissolution rates obtained by different in vitro models. The capsules showed different half-change, but comparable single-fluid dissolution profiles. Both batches of the capsules showed equivalence with respect to the extent of absorption, in connection with 100% relative bioavailability on average. A correlation of the in vivo parameters Tmax and Cmax with the half-change model can be assumed.