[Pharmacokinetics of low-dose isosorbide dinitrate and metabolites after buccal or oral administration]

The kinetics of isosorbide dinitrate (ISDN; CAS 87-33-2) and its metabolites isosorbide-5-mononitrate (IS-5-MN) and isosorbide-2-mononitrate (IS-2-MN) were examined after buccal and oral administration of 5 mg ISDN. Twelve healthy volunteers were included in a randomized cross-over study. The mean dose-corrected AUCs for total nitrate in serum after the two different preparations were in the same range. The relative bioavailability of ISDN applied buccally, however, was more than twice that after oral application. The metabolism of ISDN differed depending on the route of administration, where the AUC-ratios ISDN: IS-2-MN: IS-5-MN were 1:2.7:19.4 after buccal and 1:5.7:53.4 after oral application respectively. The absorption rate constants Ka for ISDN and the MRT after buccal and oral application did not differ significantly. The same holds for the mean residence time.