[Bioavailability of isosorbide-5-mononitrate from delayed-action formulations].

The relative bioavailability of isosorbide-5-mononitrate (IS-5-MN) has been determined after a 3-day period of dosing with 20 mg in standard-release reference tablets and sustained-release capsules at 12-h intervals, 40 mg in sustained-release capsules (Olicard 40 retard) at 24-h intervals and after single oral dose of 60 mg sustained-release capsules (Olicard 60 retard), in a cross-over study with 12 human subjects. Accumulation factors of 1.1-fold or 1.2-fold occurred during administration of 20 mg in standard- or sustained-release tablets and capsules respectively at 12-h intervals, and negligible accumulation of drug occurred after administration of 40 mg in sustained-release capsules at 24-h intervals or was calculated by the superposition principle to occur after doses of 60 mg in sustained-release capsules at 24-h intervals. The mean extent of bioavailability of IS-5-MN from the 20 mg, 40 mg and 60 mg sustained-release capsules was 79%, 67% and 70% respectively, of that from the standard-release reference tablets. The posterior probability that the bioavailability of IS-5-MN was included within the limits 60%-90% of the reference tablets was 97%, 86% and 95% for the 20 mg, 40 mg and 60 mg sustained-release capsules respectively. Means of peak plasma levels of IS-5-MN after administration of the sustained-released capsules were linearly related to the doses administered.(ABSTRACT TRUNCATED AT 250 WORDS)