Pharmacokinetics And Residual Eliminating Regularity Of Florfenicol In Sciaenops Ocellatus

As a new generation of antibiotics chloramphenicols, with rapid absorption, extensivetissue distribution, low incidence resistance and low toxicity, florfenicol have been widelyused in treatment of bacterial diseases of aquaculture economic animals. Drugconcentration in plasma and tissues of Sciaenops ocellatus were detected by a highperformance liquid chromatography~tandem mass spectrometry method (HPLC-MS-MS).In this paper, the pharmacokinetic characteristics of florfenicol in Sciaenops ocellatus wasstudied after single dose intraperitoneal injection and oral administration. Residueselimination regularity of florfenicol in Sciaenops ocellatus was study after mutiple doseoral administration.1. Pharmacokinetic characteristics of florfenicol in Sciaenops ocellatus after single doseintraperitoneal injection and oral administrationPharmacokinetic characteristics of florfenicol in Sciaenops ocellatus was studied after asingle dose of10mg/(kg.bw) following intraperitoneal injection and oral administration inthe conditions of temperature22±2℃. The concentration~time data in plasma wasanalysed by the software DAS3.0, the concentration-time data of the other tissues wasprocessed with non-compartmental statistical moments. The results showed that plasmaconcentration-time curves was best described by a two-compartment model with1st orderabsorption in intraperitoneal injection group, while the oral administration group was bestdescribed by a one-compartment model with1st order absorption. In the intraperitonealinjection group, The peak time(Tp) in plasma and liver were0.5h, which is faster than inmuscle and kidney, the maximum concentration were plasma(15.465μg/mL)>liver(9.896μg/mg)> kidney(6.831μg/mg)> muscle(2.732μg/mg). In the oraladministration group, the peak time were liver(1.5h)<plasma(2h)<kidney(4h)<muscle(4h), the maximum concentration were kidney9.095(μg/mg)> plasma(6.307μg/mL)> liver (5.439μg/mg)> muscle (5.121μg/mg). It show that florfenicol wasrapidly aborpted and distributed to the tissues, the intraperitoneal injection group was morerapidly and deeply than the oral group. The area under concentration(AUC) in muscle,liver, kidney of intraperitoneal injection group were as follow:147.643,148.108,293.408mg/(L·h), while the oral group were183.956,178.997,223.932mg/(L·h), the apparentvolume of distribution (Vd) were as follow,0.709,26.515L/h. It showed that florfenicol were widely distributed in tissues. The elimination half–life (t1/2β) in intraperitonealinjection group were muscle (40.298h)<liver (59.805h)<kidney (97.464h), while the oralgroup were muscle (34.788h)> liver (31.634h)> kidney (21.982h). It showed thatflorfenicol was slowly eliminated in tissues; in addition, the drug elimination inintraperitoneal injection group was slower than in the oral group. Moreover, drug in kidneyof intraperitoneal injection group was slowest eliminated, while drug in muscle of oraladministration was slowest eliminated.2. Residual eliminating regularity of florfenicol in Sciaenops ocellatusThe concentration time data of the other tissues was processed with non~compartmentalstatistical moments, after a multiple dose of10mg/(kg.bw) florfenicol was taken toSciaenops ocellatus with oral administration for continuously5d. The elimination half~life(t1/2β) were as follow, plasma (23.00h)<(muscle and skin)(24.57h)<liver (27.14h)<kidney (28.80h). It showed that florfenicol was slowly eliminated in tissues, the drug wasmost quickly eliminated in plasma, whereas slowest eliminated in kidney.The concentration of florfenicol in muscle and skin was far lower than in plasma andkidney after12h from stopping administration, concentration of drug in muscle and skinwas not exceeding to the Chinese and European Union’s MRLs3d later;5d later,concentration of florfenicol was below in Japanese MRLs. For the reason of no detectingflorfenicol amine, using muscle and skin for target tissue, we suggest that the withdrawalperiod of is not less than3d to reach the requirement of Chinese and European Union’sMRLs, not less than5d to reach the requirement of Janpanese MRLs.