Oxytetracycline And Sulfamethoxazole In Three Freshwater Fish In Vivo Pharmacokinetic And Residue Studies,

It's indispensable to prevent and treat aquatic diseases. And drug prevention has taken a leading position for a long time in aquaculture. It's very general to abuse drugs for pharmacokinetics and residues of drugs in aquatic product are not studied, which results in antibiotic residues. Drug residues not only influence our country's export earning of aquatic product, but also do harm to consumers. So it's urgent for us to do some researches on pharmacokinetics and residues of drugs, in order to avoid residues in aquatic products. The present study deals with pharmacokinetics and residues of oxytetracycline (OTC) and sulfamethoxazole (SMZ) in three freshwater fishes, the results are as. follows:Grass carp were treated orally via stomach tube at a single dosage of 100 mgOTC/kg at water temperature (21±1) °C. The data of pharmacokinetics were conformed to a two-compartment model. The absorption half-life (t₁/2 (ka)) was 1.57 h and the distribution half-life(t1/2(a)) was 6.52 h and the elimination half-life(t1/2(B)) was 86.85 h in serum. The present study dealt with the pharmacokinetic profile and residue elimination of OTC in grass carp. The results showed that absorption and elimination of OTC were slow, suggesting a need for long withdrawal periods (at least 25 days) prior to use of dosed fish for human consumption following oral administrations with feed at a dose of 100 mg/kg/day for 7 days at water temperature (21±1) ℃.Comparative pharmacokinetics in serum and distribution in tissues were studied in Carassius auratus administrated following two administration routes at water temperature(10±1)℃. The results indicated that OTC can be absorbed faster in serum of Carassius auratus administrated by intramuscular injection than orally via stomach tube. OTC concentrations were highest in kidney and lowest in muscle and redistribution existed in liver of Carassius auratus administrated following two administration routes.Grass carp were treated orally at a single dosage of 150 mgSMZ/kg at water temperature(21 ±1)℃. The absorption half-life (t1/2(ka) was 2.03 h and the distribution half-life(t1/2 (a) ) was 2.44 h and the elimination half-life(t1/2 (B) ) was 36.40 h in serum.The present study dealt with residue elimination of SMZ in grass carp administrated orally at a dosage of 150 mg SMZ and 30 mg TMP/kg/d for 10 days via stomach tube and with feed. And the results showed that SMZ concentrations in muscle were higher than those in kidney and liver during SMZ-elimination periods. SMZ concentrations were (0.10±0.15)mg/kg on the 19th day and fell bellow the detection limit (0.05 g/ml) on the 24th day in muscle of grass carp administrated orally via stomach tube. SMZ residues were (0.09±0.02 ) mg/kg on the 24th day and fell below the detection limit on the 27th day in the muscle of grass carp orally with SMZ-medicated feed. The residue elimination in grass carp showed that TMP concentrations in serum were lower than tissues during TMP-elimination periods. TMP concentrations fell below detection limit on the 24th day in muscle of grass carp administrated orally via stomach tube. TMP concentrations were 0.18 mg/kg on the 24th and fell below detection limit on the 27th day in muscle of grass carp administrated orally with feed. We suggested a withdrawal periods (at least 27 days) prior to use of dosed fish for human consumption following oral administrations at a dose of 150 mgSMZ and 30 mgTMP/kg/d for 10 days at water temperature ( 21 ±1) .Pengze crucian carp were treated orally at a single dosage of 150 mgSMZ /kg at water temperature (18±2.5 ) . The absorption half-life (U/2 (ka)) was 2.54 h and the distribution half-life(t1/2(a) was 3.86 h and the elimination half-life(t1/2tB>) of SMZ was 38.94 h in serum. The present study dealt with residue elimination of SMZ in pengze crucian carp administrated orally at a dosage of 150 mgSMZ and 30 mgTMP/kg/d for 10 days via stomach tube and with feed. And the results showed that SMZ concentrations in muscle were higher than those in kidney and liver during SMZ-elimination periods. The residue elimination in Pengze crucian carp showed that SMZ concentrations in muscle were higher than those in kidney and liver during SMZ-elimination periods. SMZ concentrations were highest in serum and tissues of pengze crucian carp administrated both orally via stomach tube and with feed on the 1st day. SMZ residues fell below 0.1 g/ml on the 21th and fell bellow the 0.05 jug/ml on the 22th and 24th day in muscle of pengze crucian carp administrated orally via...