Study On The Pharmacokinetics Of Thiamphenicol And HPLC Determination Of Its Residues In Chicken

The pharmacokinetics of thiamphenicol(TAP) were studied following single intravenous (i.v.) (15 mg/kg b.w.) and oral (30 mg/kg b.w.) administration of the drug in healthy chickens. Twenty birds with body weights of 1.71 to 1.79 kg were randomly divided into 2 equal groups of 10 birds each. Blood samples were collected at different interval (0.083~24h) after administration of TAP. TAP in plasma was extracted and de-proteined by ethyl acetate. The concentrations in plasma were determined by high performance liquid chromatography (HPLC) with UV detector at a detective limit of 0.0625ug/ml. The concentration-time date of TAP in plasma were analysed with 3p97 computer program.The concentration-time data of TAP in plasm after single i.v. adminstration in healthy chickens were fitted to a two-compartment open model with first-order absorption. The main pharmacokinetic parameters of TAP in chicken were as follows: V(c) 0.92±0.01 L/kg, t1/2α0.27±0.02 h, t 1/2β3.46±0.74 h, AUC 11.67±0.57 (mg/l)·h, CL(s) 1.29 L/kg/h.The concentration-time data of TAP in plasm after single oral adminstration in healthy chickens were fitted to a one-compartment open model with first-order absorption. The main pharmacokinetic parameters of TAP in chicken were as follows: Lagtime 0.043±0.01 h, t1/2ka 0.76±0.11 h, t1/2ke 2.16±0.58 h, T(peak) 1.73±0.11 h, C(max) 6.03±0.92μg/ml, AUC 32.43±0.75 mg/l·h, F 138.58±0.07%.The results of the studies showed that TAP was widely distributed, and the oral administration of TAP was rapidly absorpted. The bioavailability was high by the oral routes, these findings suggested that oral administration of TAP may be therapeutically useful aganist susceptible microorganisms in chicken.A HPLC method was delveloped for determining residues of TAP in chicken tissue. The sample was extracted with ethyl acetate, defatted with hexane, re-extracted with ethyl acetate, and cleaned up by alumin B cartridge. The cartridge was eluted with methanol-water(95:5). The standard calibration curve of drugs solution was linear in the range of 0.02~2.0μg/ml (r=0.9999). the analytes were determined with HPLC. At the fortified levels of 0.02, 0.05, 0.2 mg/kg, the mean recoveries of TAP ranged from 72.15%~76.78%; CV ranged from 3.20%~9.18%, LOD was 0.01 mg/kg, and LOQ was 0.02 mg/kg.