TY - JOUR T1 - Oseltamivir (Tamiflu) Is a Substrate of Peptide Transporter 1 JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 1676 LP - 1681 DO - 10.1124/dmd.109.026922 VL - 37 IS - 8 AU - Takuo Ogihara AU - Takashi Kano AU - Tamae Wagatsuma AU - Sho Wada AU - Hikaru Yabuuchi AU - Shigeki Enomoto AU - Kaori Morimoto AU - Yoshiyuki Shirasaka AU - Shoko Kobayashi AU - Ikumi Tamai Y1 - 2009/08/01 UR - http://dmd.aspetjournals.org/content/37/8/1676.abstract N2 - Oseltamivir, an ester-type prodrug of the neuraminidase inhibitor [3R,4R,5S]-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate phosphate (Ro 64-0802), has been developed for the treatment of A and B strains of the influenza virus but has neuropsychiatric and other side effects. In this study, we characterized the transport across intestinal epithelial cells and the absorption of oseltamivir in rats. Uptake by Caco-2 cells (human carcinoma cell line) and HeLa cells transfected with peptide transporter 1 (HeLa/PEPT1) was time- and temperature-dependent and was inhibited by typical PEPT1 inhibitors such as glycyl-sarcosine (Gly-Sar). The uptake by Caco-2 cells and HeLa/PEPT1 was saturable, with similar Km values. Oseltamivir absorption in adult rats was greatly reduced by simultaneous administration of milk, casein, or Gly-Sar. Furthermore, the plasma and brain concentrations of oseltamivir were higher in fasting than in nonfasting rats after oral administration. These results suggest that oseltamivir is a substrate of PEPT1 and that PEPT1 is involved in its intestinal absorption. ER -