Pharmacokinetics of isosorbide mononitrate in a new sustained release oral form in comparison with a conventional formulation.

40 mg of isosorbide mononitrate (isosorbide-5-mononitrate, IS5MN) in conventional (Ismo 20) and sustained release formulations (Ismo Diffutab) were administered to 5 male healthy volunteers. The administration of the sustained release formulation was repeated for seven days in order to evaluate the possible occurrence of accumulation. Pharmacokinetic data showed that the sustained release formulation reached significantly lower and delayed mean peak plasma levels compared with the conventional formulation, respectively 452.8 +/- 67.8 ng/ml and 706.7 +/- 57.3 (mean +/- SE) (p less than 0.05). Peak times were 4.6 +/- 0.2 and 2.4 +/- 0.2 (p less than 0.005) h, respectively. A longer plasma half-life together with larger AUC for the sustained release formulation was also observed. The pharmacokinetic parameters of the sustained release formulation are consistent with a therapeutic usefulness and suggest further clinical evaluation.