Pharmacokinetics of Enrofloxacin in Lutjanus sanguineus

The pharmacokinetics of enrofloxacin(EF) were investigated with a single dose of 5mg/kg body weight after peritoneal injection and oral administration in Lutjanus sanguineus at the water temperature of 26±2 ℃ and salinity of 28.Plasma and tissue concentrations of EF were simultaneously detected by the RP-HPLC.The results showed that EF concentration-time data in plasma of L.sanguineus following two different forms of administration were described as a two-compartment model with first-order absorption.The time of peak concentration(tP)were 0.75 and 1.5 h,and the maximum EF concentration(cmax) were 5.22 and 3.94 μg/mL,and the area under the concentration-time curve(AUC) were 36.98 and 17.24 mg/(L.h),and the elimination half-life(t1/2β) were 13.28 and 9.18 h.The present results indicated that enrofloxacin in L.sanguineus after peritoneal injection and oral administration had the ability to distribute widely to diverse tissues.cmax of muscle,liver and kidney were 3.53 and 3.40 μg/g,4.08 and 3.98 μg/g,11.23 and 5.40 μg/g,and tp were 1.5 and 2.0 h,1.0 and 2.0 h,0.75 and 1.5 h,and AUC were 33.17 and 23.12 mg/(L.h),39.36 and 18.20 mg/(L.h),98.97 and 56.69 mg/(L.h),respectively.Enrofloxacin eliminated slowly,and t1/2β of muscle,liver and kidney were 22.08 and 83.32 h,41.52 and 94.47 h,20.94 and 21.81 h,respectively.These results indicated the quicker absorption and faster elimination after peritoneal injection administration than that after oral administration.