Pharmacokinetics and Tissue Residues of Minocycline in Carp ( Cyprinus carpio ) after Oral Administration

The pharmacokinetics and residues elimination of Minocycline(MINO) were studied in healthy carp (Cyprinus carpio, 400 +/- 30 g) kept at water temperatures of 10 and 25 degrees C. The concentrations of MINO in plasma and tissues were determined using high-performance liquid chromatography (HPLC) using an ultraviolet detector. The plasma concentrations of MINO concentration-time data were fitted using a single-compartment model at 10 and 25 degrees C. The absorption half-life (t(1/2ka)) of MINO was 2.65 h at 10 degrees C and 1.65 hat 25 degrees C, whereas the elimination half-life (t(1/2ke)) was 11.16 h at 10 degrees C and 16.343.78 h at 25 degrees C; the maximum plasma concentration (C-max) and the time-point of maximum plasma concentration (T-p) were calculated as 2.34 mu g mL(-1) and 7.21 h at 10 degrees C, 2.97 mu g mL(-1) and 3.50 h at 25 degrees C. The distribution volume (V-d/F) of MINO was estimated to be 4.09 L kg(-1) at 10 degrees C and 2.66 L kg(-1) at 25 degrees C; the total body clearance (CLb) of MINO were computed as 0.25 and 0.49 L/(h.kg) at 10 and 25 degrees C, respectively; the areas under the concentration-time curve (AUC) was 59.07 mu g mL(-1)h at 10 degrees C and 30.72 mu g mL(-1)h at 25 degrees C. The concentrations of MINO were detected in muscle, skin, liver and kidney. The MINO could still be detected at 5 d time-point after administration at both temperatures in all tissues. The results revealed that the depletion of MINO in carp was slower with a long half-life time, especially at lower water temperature. If fish were administered MINO orally with a single dose (10 mg/kg.bw) for several days, the withdrawal periods of MINO could be not less than 19 d at winter water temperature (10 degrees C) and 8 d at summer water temperature (25.).