Food interaction pharmacokinetic study of cordaflex 20 mg retard filmtablet in healthy volunteers.

The aim of the present study was to investigate the effect of food consumption on the pharmacokinetics of Cordaflex 20 mg retard filmtablet in healthy volunteers through measuring nifedipine plasma levels by an HPLC-ED method both after fasting and food ingestion. The food interaction pharmacokinetic study of Cordaflex 20 mg retard filmtablet was carried out in 12 healthy male volunteers treated with a single dose of the preparation both after fasting and after food ingestion, in a crossover design allowing 1 week of wash-out period between the 2 treatments. Nifedipine concentration of plasma samples were determined by an isocratic HPLC-ED method [Horvai et al. 1994] with robotic sample processing [Horváth et al. 1995, 1996]. The pharmacokinetic parameters (AUC0-infinity, AUC0-t, Cmax, MRT) were analyzed by calculating 90% confidence interval for logarithmic transformed test/reference ratio values, and Schuirmann's statistical tests, the tmax and HVD values were analyzed by Wilcoxon's nonparametric statistical test. The above statistical tests of the present food interaction study indicated significant differences for each one of the respective pharmacokinetic parameter pairs calculated for treatments after fasting and after food ingestion. On the basis of the above findings and also by comparing the mean pharmacokinetic curves, it was evident, that, in agreement with the data of literature [Kleinbloesem et al. 1993, Schall et al. 1994], food ingestion increased the relative bioavailability and maximum plasma concentration (Cmax). Considering the average of the parameter values and also the respective statistical tests, it was also apparent that the time to maximum plasma concentration (tmax), the mean residence time (MRT), and the half-value duration (HVD) all decreased significantly upon the effect of food ingestion.

Human bioequivalence study of a new nifedipine containing retard filmtablet after single and repeated administration.

A clinical pharmacokinetic bioequivalence study with two retard filmtablet preparations, both containing 20 mg of nifedipine (CAS 219829-25-4) was carried out. The investigated test preparation was Cordaflex 20 mg retard filmtablet. The pharmacokinetic parameters were determined after single and repeated administration in 15 and 16 healthy male volunteers, respectively, in open, randomised studies of cross-over design. Plasma levels of nifedipine were determined by HPLC with electrochemical detection using a robotic sample preparation technique. Statistical comparison of the pharmacokinetic parameters (AUC0-infinity, AUCss, tau tmax, Cmax, Css,min, Css,av, MRT, etc.) calculated from plasma concentration-time curves by ANOVAlog, confidence interval, Schuirman's, Westlake's, Anderson's and Wilcoxon's tests, furthermore the comparison of the clinical results did not show any significant difference between the two preparations. It is concluded that the two preparations are bioequivalent after repeated administration.

Sensitive high-performance liquid chromatographic determination of nifedipine in dog plasma using an automated sample preparation system with laboratory robot.

Nifedipine, a calcium-channel blocking drug was analysed in dog plasma after oral dosing with two different formulations. Sample preparation was automated with a laboratory robot. Quantitative determination of the drug was performed on a reversed-phase HPLC system with electrochemical detection (ED) using an internal standard. Validation of the analytical method showed that the system is well suited for pharmacokinetic studies on dogs. The assay was linear in the range 1-50 ng/ml. Inter-day and intra-day variability were between 6.43-18.15% C.V. and 1.57-5.53% C.V., respectively.