The effects of food and posture on the pharmacokinetics of a biphasic release preparation of nifedipine.

The pharmacokinetics of a novel 20 mg biphasic release tablet of nifedipine were compared with the conventional 10 mg capsule and 20 mg sustained release preparations in healthy volunteers. The influence of food and posture on the pharmacokinetics of the biphasic tablet were studied. In the fasting state, the time to peak concentration of nifedipine was not significantly different between the 20 mg biphasic and 20 mg sustained release tablets, but plasma concentrations were higher between 2 and 4 h after the biphasic tablet. The terminal elimination half-lives of the two formulations were similar. In subjects who fed prior to nifedipine administration there was no significant difference between either the peak plasma concentration or terminal half-life of the biphasic tablet and two 10 mg capsules of nifedipine. When the biphasic preparation was given after a standard breakfast, the time to peak plasma concentration was significantly longer and the terminal half-life shorter than when given in the fasting state. The dissolution characteristics of the biphasic tablet were influenced by prior administration of food to an extent which may be of clinical significance during twice daily administration.