Cross-Species Comparison of the Metabolism and Excretion of Zoniporide: Contribution of Aldehyde Oxidase to Interspecies Differences
作者:Deepak Dalvie、Chenghong Zhang、Weichao Chen、Teresa Smolarek、R. Scott Obach、Cho-Ming Loi
DOI:10.1124/dmd.109.030783
日期:2010.4
Excretion and metabolism of zoniporide were investigated in humans after intravenous infusion of [14C]zoniporide at an 80-mg dose. Bile was the primary route of excretion because 57% of dose was recovered in the feces after intravenous infusion. Zoniporide was primarily cleared via metabolism in humans. 2-Oxozoniporide (M1) was the major excretory and circulating metabolite in humans and was catalyzed by aldehyde oxidase ( K m of 3.4 μM and V max of 74 pmol/min/mg protein). Metabolites M2 (17% of the dose) and M3 (6.4% of circulating radioactivity), in which the guanidine moiety was hydrolyzed to a carboxylic acid, were also detected in human feces and plasma, respectively, suggesting that hydrolysis was another route of metabolism of zoniporide in humans. The metabolism and excretion of [14C]zoniporide in rats and dogs were also evaluated. As in humans, bile was the primary route of excretion of the radiolabeled material in both species, and metabolism was the primary route of clearance. A comparison of plasma metabolites showed that for M3, rats had a higher concentration than human or dog. M1 was absent in dog and present in human and rat plasma at comparable levels, whereas comparison of excreta showed that the total body burden of M1 was greater in rat than that in human. No further evaluation of M2 was considered because it was detected only in the human fecal extracts. Hence, no further toxicological evaluation of the three human metabolites was undertaken.
在静脉注射 80 毫克剂量的 [14C]zoniporide 后,研究人员对人体内 zoniporide 的排泄和代谢情况进行了调查。胆汁是主要的排泄途径,因为静脉注射后有 57% 的剂量从粪便中排出。唑尼哌主要通过人体代谢清除。2-Oxozoniporide (M1)是人体的主要排泄和循环代谢物,由醛氧化酶催化(K m 为 3.4 μM,V max 为 74 pmol/min/mg蛋白质)。在人的粪便和血浆中也分别检测到了代谢物 M2(占剂量的 17%)和 M3(占循环放射性的 6.4%),其中胍基被水解为羧酸,这表明水解是唑尼哌在人体内代谢的另一个途径。我们还评估了[14C]佐尼坡里德在大鼠和狗体内的代谢和排泄情况。与人类一样,胆汁是这两种动物排泄放射性标记物质的主要途径,而代谢则是清除的主要途径。对血浆代谢物的比较显示,大鼠的 M3 浓度高于人类或狗。狗体内没有 M1,而人和大鼠血浆中的 M1 含量相当,而排泄物的比较表明,大鼠体内 M1 的总负荷量高于人类。由于只在人的粪便提取物中检测到 M2,因此没有考虑对其进行进一步评估。因此,没有对这三种人体代谢物进行进一步的毒理学评估。