Pharmacokinetics of Atenolol-Nifedipine Sustained-release Tablets in Dogs

According to an open randomized crossover test,the pharmacokinetics of single and multiple oral dose of atenolol-nifedipine sustained-release tablets in six dogs were studied.Atenolol tablets and nifedipine sustained-release capsules were used as the reference preparations,respectively.The concentration in plasma was determined by LC-MS.The pharmacokinetic parameters of atenolol for the reference and test preparations after single dose were t1/2(7.26± 1.09) and(7.48±1.02)h,AUC0-t(5 737±423) and(5 957±430)ng·ml-1·h,respectively.The relative bioavailability of atenolol was(102.55±2.55)%.The pharmacokinetic parameters of nifedipine for the reference and test preparations after single dose were t1/2(7.53±0.27) and(7.33±0.29)h,AUC0-t(37.92±2.59) and(36.58±1.99)ng·ml-1·h,respectively.The relative bioavailability of nifedipine was(95.77±5.65)%.For multiple oral doses,the steady state plasma concentration of atenolol for the reference and test preparations were(296±18.1) and(306±17.7)ng·ml-1,while that of nifedipine were(1.89±0.14) and(1.87±0.18)ng·ml-1.