Pharmacokinetics and Metabolism of Streptochlorin and Its Synthetic Derivative, 5-Hydroxy-2′-isobutyl Streptochlorin, in Mice

• Published in: Biological & pharmaceutical bulletin Vol. 41; no. 3; pp. 326 - 337
• Main Authors: Zhou, Yuanyuan, Choi, Yeon Jung, Kim, Eunyeong, Oh, Mun Hwan, Shin, Hee Jae, Kim, Sang Kyum, Lee, Kiho
• Format: Journal Article
• Language: English
• Published: Japan The Pharmaceutical Society of Japan 2018; Pharmaceutical Society of Japan; Japan Science and Technology Agency
• Subjects: 5-hydroxy-2′-isobutyl streptochlorin; Bioavailability; Indoles; Intravenous administration; Liability; Liver; Metabolic pathways; Metabolism; Metabolites; Microsomes; Optimization; Oral administration; Pharmacokinetics; Plasma; Radioactive half-life; streptochlorin; pharmacokinetics; metabolism; streptochlorin; 5-hydroxy-2′-isobutyl streptochlorin
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.b17-00654

The purpose of this study was to investigate the pharmacokinetics and metabolism of streptochlorin and its derivative 5-hydroxy-2′-isobutyl streptochlorin (HIS) in mice. Plasma concentration of streptochlorin declined rapidly resulting in a high sustemic plasma clearance (CLp) (5.8±1.7 L/h/kg), a large volume of distribution (Vss) (1.4±0.9 L/kg) and a short half-life (t1/2) (0.4±0.1 h) after a single intravenous administration (5 mg/kg). Oral bioavailability (F) was 10.3±3.4% after a single oral administration (10 mg/kg). HIS also showed a rapid plasma decline with a high CLp (11.3±8.8 L/h/kg), a high Vss (0.8±1.0 L/kg) and a short t1/2 (0.070±0.004 h) following intravenous administration. It was not detected in plasma after oral administration. Metabolic stability studies using mouse liver microsomes and S9 fractions predicted a high hepatic clearance for both compounds, consistent with the in vivo data. Metabolite identification studies revealed three metabolic pathways for streptochlorin: monooxygenation, glucuronidation of the indole moiety and oxidative opening of the 4-chlorooxazole ring. HIS was metabolized via monooxygenation of the isobutyl chain and glucuronidation of the indole ring. These results may aid in structural optimization to mitigate the metabolic liability of streptochlorin.