The pharmacokinetics of a new sustained release tablet (40 mg, "test") of isosorbide-5-mononitrate (CAS 16051-77-7, IS-5-MN) was investigated together with a reference preparation (20 mg, "reference") after single and multiple oral administration in ten healthy human subjects using an open, randomised two-way crossover experimental design. Based on the statistical evaluation of the area under the plasma concentration-time curve (AUC), the two tablet formulations are judged to be the same with regard to the amount absorbed. Pharmacokinetic data showed that with the test tablet significantly lower and delayed mean peak plasma levels (Cmax) were reached compared with the reference preparation in both single and multiple dose studies. The test formulation also produced lower minimum plasma concentration (Cmin). However, there was no statistically significant difference for other pharmacokinetic parameters, including the elimination rate constant (Kel), the elimination half-life (t1/2) and the peak-trough fluctuation constant (PTF) between the two treatments. It was demonstrated that the new sustained release formulation of isosorbide-5-mononitrate could be useful in clinical practice for the treatment of angina pectoris and congestive heart failure.