Yoshimura H, Yanai A, Matsumoto H, Ida K, Kurami M, Yonekura Y, Torizuka K
Central Research Laboratory, Nihon Medi-Physics Co., Ltd., Chiba.
Kaku Igaku. 1995 Sep;32(9):1037-43.
The biodistribution, metabolism and excretion of 123I-iomazenil have been studied in rats, rabbits and humans following i.v. administration. In all the species, 123I-iomazenil was rapidly metabolized and more than 90% of the administrated radioactivity was excreted within the first 24 hr. Dominant metabolites were acid metabolite (R-COOH), glucuronide of the acid (R-COOH-Glc) and free iodide (I-) in rats and humans. On the other hand, R-COOH, oxidative metabolite (R'-CH2COOH) and I- were found in rabbits. Thus, the possible metabolic pathways of iomazenil were hydrolysis, oxidation, conjugation and deiodination. The radioactivity was excreted into both urine and feces in rats, while primary route of excretion in rabbits and humans was from the kidneys. At 3 hr after injection, more than 97% of the radioactivity in rat brain was found in the form of the parent compound. This result indicates that metabolites of 123I-iomazenil do not cross the blood-brain barrier.
静脉注射给药后，已在大鼠、兔子和人类中研究了123I-碘美西泮的生物分布、代谢和排泄情况。在所有物种中，123I-碘美西泮均被迅速代谢，超过90%的给药放射性在最初24小时内排出体外。在大鼠和人类中，主要代谢产物为酸性代谢物（R-COOH）、该酸的葡糖醛酸苷（R-COOH-Glc）和游离碘化物（I-）。另一方面，在兔子中发现了R-COOH、氧化代谢物（R'-CH2COOH）和I-。因此，碘美西泮可能的代谢途径为水解、氧化、结合和脱碘。放射性物质在大鼠中经尿液和粪便排出，而在兔子和人类中的主要排泄途径是通过肾脏。注射后3小时，大鼠脑中超过97%的放射性以母体化合物的形式存在。这一结果表明，123I-碘美西泮的代谢产物不会穿过血脑屏障。
