Nifedipine Bioequivalence Study

The study was on the basis of Nifedipine sustained-release tablets.The pharmacokinetic study was conducted by measuring the Nifedipine plasma concentration and calculating the pharmacokinetic parameters using the developed and validated bioanalytical method.The bioequivalence between the two treatments was evaluated.The study developed and validated the LC-MS method for the quantitation of Nifedipine in the plasma samples.The chromatographic conditions were as following:Column-Kromasil C₁₈,mobile phase-acetonitrile:water,the Nifedipine m/z 347.05([M+H]⁺)and Diazepam m/z 285.00([M+H]⁺)for quantitation.The ether was used as extraction solvent and the internal standard was diazepam.The method was accurate,simple,reliable and suitable for Nifedipine pharmacokinetic and bioequivalence study.The human plasma samples were obtained at certain time points after the single or multiple-dose studies.Plasma samples were prepared by liquid-liquid extraction using diazepam as the internal standard.The pharmacokinetic parameters were calculated and the bioequivalence of Nifedipine sustained-release tablets was evaluated.The main pharmacokinetic parameters of Nifedipine test and reference treatment after the single-dose studies were as following:t_max(2.2±0.7)and(2.3±0.8)h;C_max(68.3±23.2)and(71.1±18.6)ng·mL^-1;t_1/2(6.0±2.1)and(6.2±3.4)h。The relative bioavailability of Nifedipine sustained-release tablets was(102.1±18.4)%.The main pharmacokinetic parameters after the multiple - dose studies were as following:t_max(2.0±0.8)and(2.2±0.9)h;C_max(63.1±26.8)and(63.5±24.7)ng·mL^-1;t_1/2(7.1±2.6)and(7.2±2.6)h;The relative bioavailability of Nifedipine sustained-release tablets was(103.3±39.8)%.The statistical analysis results show that the two treatments are bioequivalent.The formulation shows the characteristic of sustained.