Absorption of the stable prostacyclin analogue iloprost through the ulcer base in chronic venous insufficiency.

Iloprost, a stable prostacyclin analogue, is known to have beneficial effects on the disturbed microcirculation. To develop a topical application for venous leg ulcers it is necessary to know the extent to which iloprost might be absorbed through the ulcer base. The aim of this study was to measure the absorption kinetics of iloprost solutions in increasing concentrations and doses (0.004% [15 micrograms]-0.006% [30 micrograms]) in 23 patients. There was considerable variation amongst the patients in the amount of iloprost absorbed. In 40% of patients no iloprost could be detected in the plasma, whereas in others up to 82% of the iloprost applied was absorbed through the ulcer base. High iloprost plasma levels provoked flushing in two patients. The highest plasma levels were always reached during the first hour after application. There was no direct relation between the ulcer size and the amount of iloprost absorbed. Iloprost concentrations up to the highest concentration applied (0.006%) were well tolerated locally.