[Pharmacokinetic profile and bioavailability of a new pharmaceutical formulation of isosorbide-5-mononitrate sustained-release formulation]

Abstract

The pharmacokinetic profile and the bioavailability of a new galenic formulation of isosorbide-5-mononitrate sustained released capsules (Olicard 40 retard) was tested under standardized conditions. 12 healthy, male volunteers (mean age 24.9 +/- 3.0 years) in a randomized, intraindividual crossover design (wash-out phase: 6 days) received the isosorbide-5-mononitrate sustained-release capsules (testformulation) and a standard-release formulation of the same active substance as single dose (40 mg each). Venous blood sampling for analysing the plasma concentration of isosorbide-5-mononitrate was done before and at 21 fixed times after medication. The AUC0----36h of the concentration/time curve was calculated using the linear trapezoidal rule and the AUC0----infinity extrapolated after computing the half-life of the terminal elimination phase. The leading variable was the AUC0----infinity. For the sustained-release preparation an AUC0----36h of 5764.5 +/- 909 ng/ml.h was measured, an AUC0----infinity of 5863.9 +/- 981.9 ng/ml.h was calculated, with a peak maximum (Cmax) of 472.5 +/- 29.7 ng/ml after 2.9 +/- 0.5 h (tmax). For the standard-release formulation an AUC0----36h of 5679.8 +/- 690.3 ng/ml.h was measured, an AUC0----infinity of 5688.7 +/- 695.7 ng/ml.h was calculated, with a peak maximum (Cmax) of 842.4 +/- 100.2 ng/ml after 1.2 +/- 0.2 h (tmax). The bioavailability of the standard-release formulation was postulated to be 100%. The non-parametric calculation of the bioavailability-ratio (geometric Walsh-averages) was 101.47% (95% confidence limits 85.24% to 121.09%). There was no statistically significant difference between the both galenical formulations, the sustained-release preparation has no influence on the total amount of resorption.(ABSTRACT TRUNCATED AT 250 WORDS)