[Bioavailability and pharmacokinetics of a new nifedipine preparation in healthy volunteers].

In the course of this trial the bioavailability and the essential pharmacokinetic parameters of a newly developed 10 mg nifedipine preparation were to be determined in comparison to a marketed reference preparation after single oral administration. For this purpose, the test and the reference preparation were examined in 16 healthy volunteers according to a randomized 2-way cross-over design (latin square), blood samples were withdrawn up to 16 h p.a. and plasma concentrations of nifedipine and NPO (primary metabolite of nifedipine) were quantified by a HPLC method. Both preparations led to mean maximum concentrations of nifedipine in plasma of 110 mg/ml about 0.5 h p.a.; the mean termial half-lives were 1.8 h (test preparation) and 1.7 h (reference preparation). The data found for the metabolite NPO largely corresponded to those of the parent substance, thus equal metabolisation and adequate pharmaceutical quality of the two galenics may be presumed. Statistical comparison (ANOVA, Pratt-Wilcoxon test) did not reveal any significant differences between the test and reference preparation and, apart from a minor deviation, confidence intervals according to Westlake were sufficiently small, such that the two formulations may be considered bioequivalent. No differences of clinical relevance were detected between the two preparations in assay. The undesired side effects/concomitant symptoms known after nifedipine administration were observed.