磺胺甲噁唑和磺胺嘧啶在青石斑鱼组织中的分布及代谢规律

通过一次性投喂各含有200 mg/kg磺胺甲噁唑（sulfamethoxazole，SMZ）和磺胺嘧啶（sulfadiazine，SDZ）的饲料，研究两种药物在青石斑鱼中各组织分布与消除规律。采用超高效液相色谱-串联质谱检测青石斑鱼各组织中SMZ和SDZ的含量，并用内标法定量。结果表明，SMZ在青石斑鱼各组织中的最大含量：肝脏、背肌、血浆、肾脏和鳃依次为827.97μg/kg、776.70μg/kg、610.29μg/L、432.14μg/kg和345.18μg/kg。SDZ在青石斑鱼各组织中的最大含量：肝脏、背肌、鳃、血浆和肾脏依次为895.30μg/kg、660.55μg/kg、431.88μg/kg、419.56μg/L和310.67μg/kg。SMZ在青石斑鱼各组织中的半衰期：肾脏、鳃、背肌、血浆和肝脏半衰期依次为26.65、21.00、20.38、18.73h和16.90h。SDZ在青石斑鱼各组织中的半衰期：肾脏、血浆、鳃、背肌和肝脏依次为31.50、27.72、24.75、21.66h和18.24h。SMZ和SDZ在青石斑鱼肝脏中半衰期最短，代谢速度最快；在肾脏中半衰期最长，代谢速度最慢。在水温（25±2）℃条件下，SMZ和SDZ各200mg/kg的剂量同时单次投喂青石斑鱼，建议休药期不低于3d。SMZ和SDZ代谢规律研究为磺胺类药物在水产品中的合理使用提供了参考。

Distribution and Metabolism Patterns of Sulfamethoxazole and Sulfadiazine in Yellow Grouper (Epinephelus awoara) Tissues

In this study, yellow grouper (Epinephelus awoara) were administered with a single dose (200 mg/kg) of sulfamethoxazole (SMZ) and sulfadiazine (SDZ) incorporated in the diet to investigate the distribution and elimination patterns of SMZ and SDZ in various fish tissues. Both sulfonamides were detected by high performance liquid chramotography-tandem mass spectrometry (HPLC-MS/MS) and quantified by the internal standard method. The results showed that SMZ concentrations in fish tissues were in the following order: liver 827.97 (μg/kg) > muscle (776.70 μg/kg) > blood (610.29 μg/L) > kidney (432.14 μg/kg) > gill (345.18 μg/kg), while SDZ concentrations in fish tissues were in the following order: liver (895.30 μg/kg) > muscle (660.55 μg/kg) > gill (431.88 μg/kg) > blood (419.56 μg/L) > kidney (310.67 μg/kg). The elimination half-life of SMZ in fish tissues was in the following order: kidney (26.65 h) > gill (21.00 h) > muscle (20.38 h) > blood (18.73 h) > liver (16.90 h), while that of SDZ in fish tissues was in the following order: kidney (31.50 h) > blood (27.72 h) > gill (24.75 h) > muscle (21.66 h) > liver (18.24 h). The elimination half-lives of two sulfonamides in liver were much shorter than all other tissues and they were metabolized at a faster rate in liver. On the contrary, the sulfonamides showed the longest elimination half-life and were metabolized at the fastest rate in kidney among the tissues tested. After simultaneous administration of single-dose SMZ and SDZ to fish living at (25 ± 2) ℃, the withdrawal period should last at least 3 days. In conclusion, our study provides a theoretical and experimental basis for reasonable application of SMZ and SDZ in fish farming.