Pharmacokinetics and bioavailability of three different galenic nifedipine preparations

In a randomized three-way crossover study with twelve volunteers the bioavailability and main pharmacokinetic parameters of three different galenic formulations of nifedipine (hard gelatine capsule with pellets = preparation A, soft gelatine capsule with liquid nifedipine = preparation B, retard-tablet = preparation C) were determined. Plasma concentrations of nifedipine were measured by capillary gas-liquid chromatography up to 24 h after single dosing as well as up to 48 h after multiple doses of the drugs (steady state). Statistically significant differences between the preparations were found for AUC, Cmax, and Tmax. In all respects preparation A was intermediate to the other preparations. Plasma levels of 40 ng/ml or more were reached for most subjects within the first half hour after application of a single dose of preparation A and under steady state conditions plasma concentrations of 25 ng/ml or more could be upheld with this preparation for a longer time than with the reference retard tablet (preparation C). No accumulation of nifedipine in plasma occurred following multiple dosing.