A total of 8 subjects will be randomly assigned in a 3:1 ratio to receive a single dose of either CNM-Au8 (n=6) or placebo (n=2) at an initial dose level of 15 mg CNM-Au8. Additional cohorts of 8 subjects will be enrolled to investigate escalating single doses of CNM-Au8 at 30, 60, and 90 mg. Cohorts will be balanced by sex with no more than 2/3rd of subjects being of one sex.