Study of Escalating Doses of NRL001 Given in Slow-release Rectal Suppositories of Different Weights

Four single doses of NRL001 or placebo. NRL001 is administered at lower (5, 7.5 and 10 mg) or higher (10, 12.5 and 15 mg) doses in a slow release rectal suppository weighing either 1 g or 2 g.