Metabolism and Pharmacokinetics of 3-<i>n</i>-Butylphthalide (NBP) in Humans: The Role of Cytochrome P450s and Alcohol Dehydrogenase in Biotransformation
作者:Xingxing Diao、Pan Deng、Cen Xie、Xiuli Li、Dafang Zhong、Yifan Zhang、Xiaoyan Chen
DOI:10.1124/dmd.112.049684
日期:2013.2
3- n -Butylphthalide (NBP) is a cardiovascular drug currently used for the treatment of cerebral ischemia. The present study aims to investigate the metabolism, pharmacokinetics, and excretion of NBP in humans and identify the enzymes responsible for the formation of major metabolites. NBP underwent extensive metabolism after an oral administration of 200 mg NBP and 23 metabolites were identified in human plasma and urine. Principal metabolic pathways included hydroxylation on alkyl side chain, particularly at 3-, ω -1-, and ω -carbons, and further oxidation and conjugation. Approximately 81.6% of the dose was recovered in urine, mainly as NBP-11-oic acid (M5-2) and glucuronide conjugates of M5-2 and mono-hydroxylated products. 10-Keto-NBP (M2), 3-hydroxy-NBP (M3-1), 10-hydroxy-NBP (M3-2), and M5-2 were the major circulating metabolites, wherein the areas under the curve values were 1.6-, 2.9-, 10.3-, and 4.1-fold higher than that of NBP. Reference standards of these four metabolites were obtained through microbial biotransformation by Cunninghamella blakesleana . In vitro phenotyping studies demonstrated that multiple cytochrome P450 (P450) isoforms, especially CYP3A4, 2E1, and 1A2, were involved in the formation of M3-1, M3-2, and 11-hydroxy-NBP. Using M3-2 and 11-hydroxy-NBP as substrates, human subcellular fractions experiments revealed that P450, alcohol dehydrogenase, and aldehyde dehydrogenase catalyzed the generation of M2 and M5-2. Formation of M5-2 was much faster than that of M2, and M5-2 can undergo β -oxidation to yield phthalide-3-acetic acid in rat liver homogenate. Overall, our study demonstrated that NBP was well absorbed and extensively metabolized by multiple enzymes to various metabolites prior to urinary excretion.
,在口服200毫克NBP后,NBP在人体内经历了广泛的新陈代谢,在人体血浆和尿液中发现了23种代谢产物。主要代谢途径包括烷基侧链的羟基化,特别是3-、ω-1-和ω-碳的羟基化,以及进一步的氧化和结合。大约81.6%的剂量在尿液中回收,主要形式为NBP-11-酸(M5-2)以及M5-2和单羟基化产物的葡糖苷酸结合物。10-酮-NBP(M2)、3-羟基-NBP(M3-1)、10-羟基-NBP(M3-2)和M5-2是主要的循环代谢产物,其中曲线下面积值比NBP高1.6、2.9、10.3和4.1倍。这四种代谢产物的参考标准是通过Cunninghamella blakesleana的微生物生物转化获得的。体外表型研究表明,多种细胞色素P450(P450)同工酶,特别是CYP3A4、2E1和1A2,参与了M3-1、M3-2和11-羟基-NBP的形成。以M3-2和11-羟