2-溴-4-氟乙酰苯胺在雄性大鼠体内的毒物动力学行为

Toxicokinetics of 2-bromo-4-fluoroacetanilide in male SD rat

2-溴-4-氟乙酰苯胺(2-bromo-4-fluoroacetanilide,BFAA)是多种N-苯基酰胺类化合物合成的中间体,也是合成农药时的主要杂质。本研究建立了一种快速、特异的超高效液相色谱-串联质谱(UPLC-MS/MS)检测方法,用于测定大鼠血浆、组织、尿液和粪便中的2-溴-4-氟乙酰苯胺含量,以获得该化合物的吸收、分布及排泄等动力学信息。大鼠经不同剂量的2-溴-4-氟乙酰苯胺灌胃和静脉注射染毒处理后,取血浆及不同组织样品,经蛋白质沉淀法处理后采用所建立的UPLC-MS/MS方法测定,分别计算2-溴-4-氟乙酰苯胺的血药浓度达峰时间(t_(max))、血药峰浓度(C_(max))和药-时曲线下面积(AUC(0-t))等血浆毒物动力学参数和绝对生物利用度(F),考察了药物在组织中的分布和经尿液、粪便排泄的特征。血浆毒物动力学研究表明:大鼠灌胃后药物可被迅速吸收,给予200、500和1 000 mg/kg的2-溴-4-氟乙酰苯胺后,其t_(max)值分别为(0.2±0.1)、(0.4±0.2)和(0.5±0.3) h;C_(max)和AUC(0-t)值分别为(32.4±5.0)、(45.2±1.8)、(38.5±3.2)mg/L和(121.2±40.9)、(393.3±51.1)、(321.9±38.0)(mg/L)·h;F值在34.1%~83.3%之间。其血浆药-时曲线具有双峰现象,推测可能存在重吸收或肠-肝循环。组织分布研究表明:2-溴-4-氟乙酰苯胺在组织中分布较广,且主要分布在小肠、胃和脂肪中;此外在脑和睾丸中发现了少量该化合物,表明其可以穿过血脑屏障和睾丸屏障;24 h后大部分组织中已检测不到该化合物,表明其总体不存在蓄积现象;靶向分配系数均小于1.0,提示2-溴-4-氟乙酰苯胺对组织无明显的选择性。排泄研究结果表明:2-溴-4-氟乙酰苯胺经尿液和粪便的排泄主要发生在0~48 h内,分别占总排泄量的93%和92%;经尿液和粪便的总排泄量为(80.6±29.8)μg,仅占总染毒量的(0.03±0.01)%,提示经尿液和粪便的排泄并非2-溴-4-氟乙酰苯胺母体化合物主要的体内消除途径。

2-Bromo-4-fluoroacetanilide(BFAA) is an intermediate in the synthesis of many Nphenylamides and an important impurity in the synthesis of pesticides. An ultra performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) method was developed for the rapid and specific determination of BFAA in rat plasma, tissue, urine and feces to obtain the toxicokinetic information of absorption, distribution and excretion of the compound. Plasma and different tissue samples of rats were obtained and processed by protein precipitation method after intragastric and intravenous administration with different doses of BFAA, and the validated UPLC-MS/MS method was used for detection. The absorption toxicokinetic parameters such as the peak time(t_(max)), the peak plasma drug concentration(C_(max)) and the area under the drug concentration-time curve(AUC(0-t)), and bioavailability of BFAA were calculated. And the tissue distribution and excretion characteristics of urine and feces were investigated. The results of plasma toxicokinetic studies indicated that the drug was rapidly absorbed after intragastric administration, and the t_(max) value of the plasma concentration of BFAA was(0.2 ± 0.1),(0.4 ± 0.2) and(0.5 ± 0.3) h after given at 200, 500 and 1 000 mg/kg,respectively. The C_(max) and AUC(0-t) value were(32.4±5.0),(45.2±1.8),(38.5±3.2) mg/L and(121.2±40.9),(393.3±51.1),(321.9±38.0)(mg/L)·h, respectively. The bioavailability(F) of BFAA reached 34.1%-83.3%, and the plasma drug time curve had a double-peak phenomenon. It is speculated that there may be reabsorption or intestinal-hepatic circulation in animals. The results of tissue distribution studies showed that BFAA was widely distributed in the tissues and mainly distributed in small intestine, stomach and adipose tissue. In addition, a small fraction of BFAA was found in the brain and testis which indicated that the compound could cross the blood-brain barrier and testicular barrier. BFAA was eliminated in most tissues within 24 hours which indicated that there was no accumulation of the compound. The target distribution coefficient study suggested that BFAA has no obvious selectivity for tissues. Excretion through urine and feces mainly occurred within 0 to 48 hours,accounting for 93% and 92% of total excretion, respectively. The total excretion amount in urine and feces is(80.6 ± 29.8) μg, which only accounts for(0.03 ± 0.01) %, suggesting that the excretion in urine and feces is not the main elimination way of BFAA prototype compound in vivo.