Evaluation of the bioequivalence and pharmacokinetics of two tablet formulations of isosorbide-5-mononitrate after single oral administration in healthy volunteers.

The pharmacokinetic parameters of two oral formulations of 20 mg tablets of isosorbide-5-mononitrate (CAS 16051-77-7, Dilavenil as test and another commercially available preparation as reference) were compared in an open-label, randomized, single oral dose, two-period cross-over design in 20 healthy volunteers under fasting conditions. Plasma concentrations of isosorbide-5-mononitrate were measured by a validated gas chromatographic assay. The parametric 90% confidence intervals of the geometric mean values of the test/reference ratios were 101.2% to 108.5% (point estimate: 104.7%) for AUC0-variation of, 101.6% to 110.7% (point estimate: 106.2%) for AUC0-t, and 98.1% to 115.5% (point estimate: 106.1%) for Cmax, within the acceptance criteria for bioequivalence (80%-125%). Tmax values were analyzed by the nonparametric Wilcoxon test and the difference was not statistically significant. Therefore, it is concluded that the test and reference isosorbide-5-mononitrate formulations are bioequivalent for both the extent and the rate of absorption.