Studies on pharmacokinetics of oxytetracycline in Paralichthys olivaceus in vitro

The pharmacokinetic of oxytetracycline in healthy Paralichthys olivaceus was studied by using the high performance liquid chromatography.Data were analyzed with the pharmacokinetic computer program DAS.The results showed that the plasma concentration time course of oxytetracycline can be described by a one-compartment open model with the first order absorption after oral administration(200 mg/kg).The main pharmacokinetic parameters were as follows: distribution half-life(T(1/2)a) was 10.043 h,time to peak(Tmax) was 4.000 h,peak concentration(Cmax)was 0.54 mg/L,area under the concentration-time curve from 0 to 72h(CAU0-72) was 17.15(mg h/L),rate constant for distribution(Ka) was 0.223,and rate constant for elimination(k) was 0.476 h-1.The kinetics process of oxytetracycline in muscle can be described by a one-compartment model with the first order absorption.Its theoretical equations were as follows: T(1/2)a was 74.893 h,Tmax was 4.000 h,Cmax was 3.58 mg/L,CAU0-72 was 148.56(mg h/L),Ka was 0.731,k was 2.991 h-1.The kinetics process of oxytetracycline in liver was found to be a one-compartment with the first order absorption.Its theoretical equations were as follows: T(1/2)a was 31.376 h,Tmax was 4.000 h,Cmax was 13.78 mg/L,CAU0-72 was 494.136(mg h/L),Ka was 0.876,and k was 4.940 h-1.