Pharmacokinetics of Enrofloxacin in Macrobrachium rosenbergii

The pharmacokinetics of enrofloxacin(ENR)and ciprofloxacin(CIP)in hemolymph,hepatopancreas and muscle of the Macrobrachium rosenbergii were investigated using the reverse-phase high performance liquid chromatography(RP-HPLC).The average recovery rates of ENR in three tissues were 86.54%±2.39%,85.43%±2.75%,and 95.01%±1.99%,respectively,and the average recovery rate of CIP in three tissues were 94.34%±8.30%,75.17%±5.42%,and 80.42%±1.67% respectively in the three tissues;The intra-day precision rates of ENR and CIP were 3.39%±0.53% and 3.92%±1.24%,respectively,and the inter-day precision rates were 5.11%±1.73% and 5.28%±2.10%,respectively.The lowest detected limit of enrofloxacin in tissues was 0.02 μg/ml,and that of ciprofloxacin was 0.01 μg/ml.The data were analyzed with the pharmacokinetic computer program MCPKP.The main pharmacokinetic parameters of ENR in hemolymph were t_ 1/2α 0.581 h,t_ 1/2β 69.315 h,V_d/F 7.230 L/kg,C_L/F 0.035 L/h·kg,K_ 12 0.01/h,K_ 21 0.005/h,AUC 291.898 μg/ml·h,T_ max 0.083 h,and C_ max 6.293 μg/ml;the main pharmacokinetic parameters of NER in hepatopancreas and muscle were t_ 1/2α 1.941 h,t_ 1/2β 70.732 h,AUC 308.07 μg/ml·h,t_ 1/2α 0.000 h,t_ 1/2β 59.456 h,and AUC 217.039 μg/ml·h.Ciprofloxacin,the main active metabolite of enrofloxacin,exists in relatively low levels in all the main tissues of the shrimp,but its kinetics in the hemolymph could not be described by a one-or two-compartment open model.