文章基本信息

标题：Identification of Human Drug-Metabolizing Enzymes Involved in the Metabolism of SNI-2011
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作者：Takuo WASHIO ; Hirohiko ARISAWA ; Kazuhiro KOHSAKA 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2001
卷号：24
期号：11
页码：1263-1266
DOI：10.1248/bpb.24.1263
出版社：The Pharmaceutical Society of Japan
摘要：In vitro studies were conducted to identify human drug-metabolizing enzymes involved in the metabolism of SNI-2011 ((±)-cis-2-methylspiro [1,3-oxathiolane-5,3'-quinuclidine] monohydrochloride hemihydrate, cevimeline hydrochloride hydrate). When ¹⁴C-SNI-2011 was incubated with human liver microsomes, SNI-2011 trans-sulfoxide and cis-sulfoxide were detected as major metabolites. These oxidations required NADPH, and were markedly inhibited by SKF-525A, indicating that cytochrome P450 (CYP) was involved. In a chemical inhibition study, metabolism of SNI-2011 in liver microsomes was inhibited (35-65%) by CYP3A4 inhibitors (ketoconazole and troleandomycin) and CYP2D6 inhibitors (quinidine and chlorpromazine). Furthermore, using microsomes containing cDNA-expressed CYPs, it was found that high rates of sulfoxidation activities were observed with CYP2D6 and CYP3A4. On the other hand, when ¹⁴C-SNI-2011 was incubated with human kidney microsomes, SNI-2011 N-oxide was identified as a major metabolite. This N-oxidation required NADPH, and was completely inhibited by thiourea, indicating that flavin-containing monooxygenase (FMO) was involved. In addition, microsomes containing cDNA-expressed FMO1, a major isoform in human kidney, mainly catalyzed N-oxidation of SNI-2011, but microsomes containing FMO3, a major isoform in adult human liver, did not. These results suggest that SNI-2011 is mainly catalyzed to sulfoxides and N-oxide by CYP2D6/3A4 in liver and FMO1 in kidney, respectively.
关键词：SNI-2011;cytochrome P450;flavin-containing monooxygenase;human liver microsome;human kidney microsome