Pharmacokinetics/Pharmacodynamics Integration of Florfenicol against E.coli in Pigs ex vivo

For the rational usage of florfenicol to treat the colibacillosis of pigs,the integration of pharmacokinetics in vivo and pharmacodynamics in vitro was used to study the antibacterial activity of florfenicol against E.coli in pig serum ex vivo.The accurate MIC of florfenicol against E.coli in MH broth and serum was 3.25 and 8.75 μg·mL-1,respectively.Florfenicol was absorbed slowly and anomaly in pigs after intramuscular administration(20 mg·kg-1).The Cmax was(5.28±1.48) μg·mL-1 at(3.60±1.52) h.The elimination of florfenicol was slow in pigs.Mean residence time(MRT) was(26.61±9.81) h.Elimination half-life(t1/2β) was(17.49±8.04) h.EC50 was(7.76±4.53) h.AUC0→24/MIC was(7.69±1.48) h and Cmax/MIC was(0.60±0.17).Because of the poor activity of florfenicol against E.coli and the lower plasma Cmax of florfenicol in pigs,it may fail to get desirable treatment result when curing the infection of E.coli in pigs by the routine regimen.