Pharmacokinetics and Bioequiavailability of Norfloxacin Intragastric Floating Sustained-release Tablets in Dogs

OBJECTIVE:To study the pharmacokinetics and bioavailability of norfloxacin intragastric floating sustained-release tablets(NIFST)vs.its conventional tablets in dogs.METHODS:By a randomized crossover self-control design,6 healthy dogs were randomly assigned to receive 400 mg NIFST(1 tablet)or its conventional tablets(4 tablets).Femoral venous blood samples were taken at 0.5,1,2,3,4,6,8,10,13,16 and 24 h respectively after oral medication.The concentration of norfloxacin in plasma was determined by RP-HPLC and fitted using 3p97 pharmacokinetic program.The main pharmacokinetic parameters were computed and the relative bioavailability of the NIFST was evaluated.RESULTS:The pharmacokinetic parameters of the conventional tablets vs.NIFST were as follows:Cmax:(3.51±0.57)vs.(2.51±0.55)μg·mL-1;tmax:(1.79±0.65)vs.(3.72±0.48)h;AUC0～24:(21.10±3.14)vs.(21.31±4.32)μg·h·mL-1;MRT:(5.68±0.51)vs.(7.71±0.67)h.The relative bioavailability of NIFST was 103.5%.CONCLUSION:As compared with the conventional tablets,the NIFST had longer MRT and remarkable sustained release characteristics.The two kinds of tablets were proved to be bioequivalent.