Pharmacokinetics and Bioavailability of Enrofloxacin Microcapsules in Pigs

The plasma pharmacokinetics and bioavailability of enrofloxacin microcapsules and enrofloxacin in pigs were studied using HPLC method.Ten healthy pigs were assigned to two groups and dosed the two drugs following a single oral administration,respectively.Blood samples were collected at different intervals and extracted by methanol.Finally,the samples were detected by HPLC and were analysed using the MCPRP software package.The two drugs' concentration-time data were both fitted to a one-compartment open model with first-order absorption after a single oral administration in pigs.The main pharmacokinetic parameters of the two drugs in pigs were as follows,respectively: t1/2Ka1.73 h±0.93 h and 0.36 h±0.31 hP0.01);Tmax5.69 h±1.68 h and 2.04 h± 1.06 hP0.01);t1/2Ke16.53 h±5.23 h and 10.17 h±1.87 h(P0.01);Cmax1.71 μg/mL±0.47 μg/mL and 2.51 μg/mL±0.45 μg/mL,P0.01);AUC 51.98 μg/mL±16.08 μg/mL and 40.58 μg/mL±6.40 μg/mL per-hour.The relative bioavailability of enrofloxacin microcapsules was 128%.Results showed that,enrofloxacin microcapsule was completely absorbed with a slowly absorption rate,and which was eliminated slowly in the blood after single oral administration.