Studies On Pharmacokinetics Of Danofloxacin In Chicken And Postantibiotic Effects Of Danofloxacin In Vitro

Danofloxacin is one of the floroquinolones only used for animals infectious diseases. The pharmacokinetic characteristics and bioavailability of danofloxacin following intravenous and oral administration were conducted with chicken by using the (High performance liquid chromatography , HPLC) interal method in this study. The post-antibiotic effects (PAE) of danofloxacin in vitro against E. coli and S. aureus were tested by routine colonial counting method. And the multiple-dose pharmacokinetic parameters were assessed according to the single-dose pharmacokinetic parameters, so this can provide bases for the clinical uses of danofloxacin.The data were analyzed with the pharmacokinetic computer program MCP-KP. The pharniacokinetics showed that the plasma concentration-time course of danofloxacin by intravenous administration (5mg/kg) can be described by a two-compartment open model. The main pharmacokinetics parameters were as follows: tii2a0.33l3~0.0966h t112~5.9940~1.4089h .~ Vd7.5246*0.7515l/kgAUC5.6916~0.8178~ig/ml~h~ CLB0.8935~0.1311l/kg~h.The theoretical equation was as follows: C=1.3995e?3+0.5947&0 .1203:The concentration-time course of danofloxacin in plasma following oral administration (5mg/kg) in chicken can be described by one-compartment open model with first-order absorption. The primary parameters were showen below:tI/2Ka 0.3029~0.1754h~ tI/2K 6.5128~3.7449h tmax 1.2l00~0.4364 h~ Cmax 0.5l59~0.0399p.tg/ml AUC 5.l329~1.2849j.tg/mlh . The bioavailability was0 1236:3 3152t90.18%. The theoretical equation was as follows: C0.5598(& -&The inhibited experiment in vitro showed that the minimum inhibited concentration(MIC) of both E.coli and S.aureus was 0.25jig/ml. The post-antibiotic effects (PAE) of danofloxacin against E.coli and S.aureus in vitro at three different concentration levels were tested by routine colonial counting method. The PAE of danofloxacin against E.coli and S.aureus in vitro at the concentration levels of 0.5MIC, 2MIC and 4MIC were 0.6464~0.0294h~ l.2077~0.0284h~ 1.6529*0.0496h for E.coli, and 0.5660~0.0075h~ 1.1746~0.0057h. 1.49l3h for S.aureus respectively.The results of pharmacokinetic investigation show that after danofloxacin taking orally in chicken , it has many characteristics ,for example , it can be absorbed quickly , the distribution invitro is widespread; the precluding half time is long ; the bioavailability is excellent , the effect of absorption is well ; and so on The results showed that the PAE of danofloxacin against E.coli and S.aureus was more stronger. So binding the pharmacokinetic characteristics of danofloxacin following oral administration and the PAE in vitro , we suggest that the reasonable administration project is that the chicken can take danofloxacin once one day with oral adminstration.Postgraduate: Liu FangpingMajor: Basic Veterinary MedicineTutor:Prof. Tong Hengmin...