Bioequivalence of nifedipine sustained release tablets in healthy volunteers

Objective To evaluate the bioequivalence of nifedipine sustained release tablets in healthy volunteers.Methods The study was designed as an open randomized crossover study.Twenty healthy male volunteers were carried out with orally single-dose and multiple-dose nifedipine in test and reference preparations.The concentrations of nifedipine in plasma were determined by LC-MS/MS.The pharmacokinetic parameters and correlative bioavailabilities were statistically calculated with DAS 2.1 software.Results The main pharmacokinetic paramerters of test and reference preparations after a single dose were as follow: Cmax were(92.68± 34.98),(112.39±47.98)ng·mL-1;tmax were(2.68±0.69),(2.70±0.57) h;t1/2 were(5.01±1.65),(4.83±2.16)h;AUC0-36 h were(648.09±332.98),(659.62±376.95)ng·h·mL-1,respectively.F was(104.1±25.6)%.The CIs for the ratios of AUC0-36 h,AUC0-∞,Cmax were 94.6%-108.2%,93.9%-106.9%,72.8%-100.6%.The main pharmacokinetic paramerters of test and reference preparations after a multiple dose were as follow: Cmax were(122.85±45.46),(141.29±53.51)ng·mL-1;tmax were(2.55±0.65),(2.70±0.66) h;t1/2 were(5.57±1.91),(3.83±1.25) h; Cav were(57.36±26.31),(59.26±25.25) ng·mL-1;AUCSS were(688.26±315.67),(711.09±303.01)ng·h·mL-1;F was(99.8±29.9)%.The CIs for the ratios of AUCss,Cmax were 85.8%-107.3%,73.5%-103.2%.Conclusion The two kinds of tablets are bioequivalent.