Comparative blood level of dihydroergotoxine (DHET) after administration of two oral forms (solution & tablet): a preliminary study.

In this preliminary study, using a radioimmunoassay, we demonstrate that the DHET blood levels observed after administration of an oral solution to human subjects, were different from those obtained after administration of a slow-release table. After administration of the oral solution, the DHET blood levels rose quickly, reached a peak between 1 and 2 hours and the decrease rapidly. On the contrary, after ingestion of a slow-release tablet of DHET, the plasma levels took 6 hours to reach the maximum due to the slow release of the drug from this dosage form. In both cases, the areas under the curves were very similar but the relative bioavailability of DHET in these two forms is very different if one considers the two components of availability extent and rate. The equality of the areas under the curves indicated that the extent of DHET available was the same, but time-course of the plasma levels showed that the rate at which DHET became available was significantly slower. Therefore the tablet form has given the desired "slow-release" availability for which it was designed.