1. Faculty of Pharmaceutical Sciences; Hokkaido University; Kita-12, Nishi-6, Kita-ku, Sapporo Hokkaido 060-0812 Japan
2. Pharmaceutical Research Center; Shionogi & Co., Ltd.; 3-1-1, Futaba-cho, Toyonaka Osaka 561-0825 Japan
3. Center for Research and Education on Drug Discovery; Hokkaido University; Kita-12, Nishi-6, Kita-ku, Sapporo Hokkaido 060-0812 Japan