Pharmacokinetics, Tissue Distribution and Elimination of Sulfadiazine and Trimethoprim in Mud Crab (Scylla paramamosain) After Oral Administration

Abstract:

The pharmacokinetics, tissue distribution and elimination of sulfadiazine (SD) and trimethoprim (TMP) in mud crab (Scylla paramamosain) were investigated in order to provide scientific data to support its safe use. SD and TMP were orally administrated at a single dose of SD (83.3 mg/kg) and TMP (16.7 mg/kg) at temperature of (27±1) ℃ and seawater salinity of 10. The hemolymph concentration-time curve for SD and TMP were described by a two-compartment model with first order absorption. Peak hemolymph concentration (Cmax) for SD and TMP was 49.56 mg/L and 2.79 mg/L, respectively, and area under curve (AUC) for SD and TMP was 1417.6 mg/L·h and 82.7 mg/L·h, respectively. Of the tissues analyzed, the hepatopancreas was the tissue with the highest SD and TMP concentrations, and Cmax was 59.36 mg/kg and 74.82 mg/kg, respectively. Thus, a large amount of TMP was accumulated in the hepatopancreas, while only a small amount of TMP entered blood circulation. In gill, peak concentration for SD and TMP was 51.89 mg/kg and 42.58 mg/kg, respectively, and elimination half-life was 23.28 h and 25.29 h, respectively. The drug concentration in gill tissue was relatively high and the elimination rate was fast, suggesting crab gill plays a role in drug elimination. In muscle, peak concentration for SD and TMP was 44.95 mg/kg and 10.09 mg/kg, respectively, and elimination half-life was 25.09 h and 35.08 h, respectively. According to SD and TMP elimination and the maximum residue limit of 0.1 mg/kg for SD and 0.05 mg/kg for TMP, the theoretical withdrawal time of SD/TMP in muscle and hepatopancreas, was 290.6 h/302.8 h and 340.4 h/377.0 h, respectively.